MOVEMENT DETECTOR AND SEWING SYSTEM

Abstract

A movement detector is attachable to a presser bar of a sewing machine. The movement detector includes a sensor and a housing. The sensor is configured to emit light toward a sewing workpiece and to detect the light reflected from the sewing workpiece to detect a movement amount of the sewing workpiece. The housing accommodates the sensor. The housing includes a wall surface spaced from the sensor in a detachment direction. The detachment direction is perpendicular to an emission direction in which the sensor emits the light. The wall surface is formed with an insertion opening for inserting a presser foot.

Claims

1. A movement detector attachable to a presser bar of a sewing machine, the movement detector comprising: a sensor configured to emit light toward a sewing workpiece and to detect the light reflected from the sewing workpiece to detect a movement amount of the sewing workpiece; and a housing accommodating the sensor, the housing including a wall surface spaced from the sensor in a detachment direction, the detachment direction being perpendicular to an emission direction in which the sensor emits the light, the wall surface being formed with an insertion opening for inserting a presser foot.

2. The movement detector according to claim 1, further comprising: a lock plate accommodated in the housing and configured to lock the presser foot, the lock plate including a fitting portion having a protruding shape or a recessed shape, the fitting portion being configured to fit with a fitted portion of the presser foot in a state where the presser foot is inserted in the housing, the fitted portion having a recessed shape or a protruding shape.

3. The movement detector according to claim 2, wherein the lock plate extends in an emission surface direction perpendicular to the emission direction.

4. The movement detector according to claim 3, wherein a direction opposite the detachment direction is defined as an attachment direction; wherein a direction opposite the emission direction is defined as a reflection direction; wherein a direction including both the detachment direction and the attachment direction is defined as a slide direction; wherein movement detector further comprises a slider that is slidable in the slide direction with respect to the housing; wherein the housing further includes a slider wall surface spaced from the sensor in the reflection direction, the slider wall surface being formed with a slider opening, the slider opening extending in the slide direction; wherein the slider includes: a slider plate accommodated in the housing and extending in the emission surface direction; and a lever provided at the slider plate, the lever being exposed in the reflection direction through the slider opening; wherein the lock plate is a leaf spring; wherein the lock plate includes a protruding portion inclined with respect to the slide direction, the protruding portion protruding from the lock plate in an approach direction toward the slider plate, the protruding portion being arranged on a movement path of the slider that slides in the slide direction; and wherein, when the slider slides in the detachment direction, the slider plate contacts the protruding portion and the lock plate elastically deforms in a separation direction opposite the approach direction, thereby releasing engagement between the fitting portion and the fitted portion.

5. The movement detector according to claim 4, wherein the protruding portion is located on the movement path of the slider and downstream of the presser foot in the attachment direction in a state where the presser foot is locked; and wherein, when the slider slides in the detachment direction in a state where the presser foot is locked, the slider plate is configured to contact the protruding portion and the presser foot in this order, the engagement between the fitting portion and the fitted portion is released, and the presser foot is pushed out in the detachment direction.

6. The movement detector according to claim 1, wherein the housing includes an eaves portion, the eaves portion being provided at an end of the insertion opening in a reflection direction, the reflection direction being a direction opposite the emission direction, the eaves portion protruding in the detachment direction.

7. The movement detector according to claim 3, wherein a direction opposite the detachment direction is defined as an attachment direction; wherein a direction including both the detachment direction and the attachment direction is defined as a slide direction; wherein the lock plate is a leaf spring; wherein the lock plate includes an inclined portion that is inclined with respect to the slide direction; wherein the inclined portion is arranged on an insertion path of the presser foot that is inserted in the attachment direction through the insertion opening; and wherein, when the presser foot is inserted in the attachment direction through the insertion opening, the presser foot contacts the inclined portion and the lock plate elastically deforms by being pressed by the presser foot, and then the fitting portion fits with the fitted portion.

8. The movement detector according to claim 7, wherein the fitting portion has a protruding shape protruding in an approach direction from the lock plate toward the presser foot in a state where the presser foot is inserted in the housing, the fitting portion being configured to fit into the fitted portion having a recessed shape; and wherein the fitting portion includes the inclined portion.

9. The movement detector according to claim 1, further comprising: a guide portion arranged on an insertion path of the presser foot that is inserted in an attachment direction through the insertion opening, the attachment direction being a direction opposite the detachment direction, the guide portion being a groove or a protrusion, wherein the guide portion is configured to, when the presser foot is inserted into the housing, fit to a guided portion of the presser foot, the guided portion being a protrusion or a groove.

10. A movement detector attachable to a presser bar of a sewing machine, the movement detector comprising: a sensor configured to emit light toward a sewing workpiece and to detect the light reflected from the sewing workpiece to detect a movement amount of the sewing workpiece; a housing accommodating the sensor, the housing including a wall surface spaced from the sensor in a detachment direction, the detachment direction being perpendicular to an emission direction in which the sensor emits the light, the wall surface being formed with an insertion opening; and a presser foot including: an insertion plate inserted into the housing through the insertion opening, the insertion plate being locked in the housing; a presser plate located at a position toward the emission direction and the detachment direction from the insertion plate, the presser plate extending in a slide direction, the slide direction being a direction including both the detachment direction and an attachment direction, the attachment direction being a direction opposite the detachment direction; and a connection plate connecting the insertion plate and the presser plate, the connection plate extending in the emission direction from the insertion plate, the connection plate being formed with a connection plate opening extending in the emission direction from the insertion plate.

11. The movement detector according to claim 10, wherein a direction opposite the emission direction is defined as a reflection direction; wherein a direction perpendicular to the emission direction and the slide direction is defined as a width direction; wherein the connection plate includes a connection portion connected to the presser plate; and wherein a size in the width direction of a first end of the connection portion is smaller than a size in the width direction of a second end of the connection portion, the first end of the connection portion being an end in the emission direction, the second end of the connection portion being an end in the reflection direction.

12. The movement detector according to claim 10, further comprising a lock plate accommodated in the housing and configured to lock the insertion plate, wherein the lock plate includes a fitting portion having a protruding shape or a recessed shape; wherein the presser foot includes a fitted portion provided at the insertion plate, the fitted portion having a recessed shape or a protruding shape; and wherein the fitting portion is configured to fit with the fitted portion in a state where the insertion plate is inserted in the housing.

13. The movement detector according to claim 10, wherein a center of gravity of the presser foot is located on the insertion plate.

14. A movement detector attachable to a presser bar of a sewing machine, the sewing machine including a bed, the movement detector comprising: a sensor configured to emit light downward toward a sewing workpiece and to detect the light reflected from the sewing workpiece to detect a movement amount of the sewing workpiece, the sewing workpiece being arranged on the bed and below the presser bar, the presser bar extending in an upper-lower direction; and a housing accommodating the sensor, the housing including a wall surface spaced from the sensor in a forward direction perpendicular to the upper-lower direction, the wall surface being formed with an insertion opening for inserting a presser foot.

15. The movement detector according to claim 14, further comprising: a lock plate accommodated in the housing and configured to lock the presser foot, the lock plate including a fitting portion having a protruding shape or a recessed shape, the fitting portion being configured to fit with a fitted portion of the presser foot in a state where the presser foot is inserted in the housing, the fitted portion having a recessed shape or a protruding shape.

16. A sewing system comprising: a sewing machine configured to perform sewing on a sewing workpiece; and a movement detector configured to detect a movement amount of the sewing workpiece, the sewing machine comprising: a needle bar extending in an upper-lower direction, the needle bar being configured that a sewing needle is attachable to a lower end of the needle bar; a bed located below the needle bar; and a presser bar extending in the upper-lower direction, the needle bar and the presser bar being arranged in a front-rear direction perpendicular to the upper-lower direction, the movement detector comprising: a sensor configured to emit light downward toward the sewing workpiece and to detect the light reflected from the sewing workpiece to detect the movement amount of the sewing workpiece; and a housing accommodating the sensor, the housing including a wall surface spaced from the sensor in a forward direction, the forward direction being a direction from the presser bar toward the needle bar in the front-rear direction, the wall surface being formed with an insertion opening for inserting a presser foot.

17. The sewing system according to claim 16, wherein the movement detector further comprises: a lock plate accommodated in the housing and configured to lock the presser foot, the lock plate including a fitting portion having a protruding shape or a recessed shape, the fitting portion being configured to fit with a fitted portion of the presser foot in a state where the presser foot is inserted in the housing, the fitted portion having a recessed shape or a protruding shape.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0012] FIG. 1 is a perspective view of a sewing machine 1 to which a movement detector 2 is attached, as viewed from an upper right front side.

[0013] FIG. 2 is a left side view of the sewing machine 1 around the movement detector 2.

[0014] FIG. 3 is a perspective view of the sewing machine 1 around the movement detector 2 as viewed from a front upper side.

[0015] FIG. 4 is a perspective view of the movement detector 2 with a presser foot 5 attached thereto, as viewed from the upper right front side.

[0016] FIG. 5 is a perspective view of the movement detector 2 from which the presser foot 5 is detached, as viewed from the upper right front side.

[0017] FIG. 6 is a perspective view of the movement detector 2 with the presser foot 5 attached thereto, as viewed from a lower left front side.

[0018] FIG. 7 is a perspective view of the movement detector 2 from which an upper housing 30 is removed, as viewed from the upper right front side.

[0019] FIG. 8 is a perspective view of the movement detector 2 from which the upper housing 30 is removed, as viewed from a left front upper side.

[0020] FIG. 9 is a cross-sectional view of the movement detector 2, taken along a line IX-IX in FIG. 5 (a cross-sectional view cut in an upper-lower direction).

[0021] FIG. 10 is a cross-sectional view of the movement detector 2, taken along a line X-X in FIG. 4 (a cross-sectional view cut in the upper-lower direction).

[0022] FIG. 11 is a perspective view of a lock plate 70 and a slider 80 as viewed from the upper right front side.

[0023] FIG. 12 is a perspective view of the lock plate 70 and the slider 80 as viewed from the upper right front side in a state where the lock plate 70 locks the presser foot 5.

[0024] FIG. 13 is a perspective view of a presser foot 5A as viewed from the left front upper side.

[0025] FIG. 14 is a left side view of the presser foot 5A.

[0026] FIG. 15 is a perspective view of a presser foot 5B as viewed from the left front upper side.

[0027] FIG. 16 is a left side view of the presser foot 5B.

[0028] FIG. 17 is a perspective view of a presser foot 5C as viewed from the left front upper side.

[0029] FIG. 18 is a left side view of the presser foot 5C.

[0030] FIG. 19 is a perspective view of a movement detector 200 from which an upper housing 30 is removed, as viewed from an upper right front side.

DESCRIPTION

[0031] A sewing system 100 and a movement detector 2 according to an embodiment will be described with reference to the drawings. The sewing system 100 shown in FIG. 1 includes a sewing machine 1 and the movement detector 2. The sewing machine 1 performs sewing on a sewing workpiece C shown in FIG. 2. The movement detector 2 is attached to a presser bar 8 of the sewing machine 1 and detects a movement amount of the sewing workpiece C.

[0032] The structure of the sewing machine 1 to which the movement detector 2 is attached will be described with reference to FIG. 1. In the following description, the upper left, the lower right, the lower left, the upper right, the upper, and the lower in FIG. 1 are respectively the left, the right, the front, the rear, the upper, and the lower of the sewing machine 1 and the movement detector 2. The longitudinal direction of a bed 11 and an arm 13 is the left-right direction of the sewing machine 1. The side on which a pillar 12 is located in the left-right direction is the right side. The direction in which the pillar 12 extends is the upper-lower direction of the sewing machine 1. A light emission direction (emission direction) D of a sensor 18 of the movement detector 2 described later is downward. In the movement detector 2 described later, the direction from the sensor 18 toward a front wall 23 is forward.

[0033] As shown in FIGS. 1 to 3, the sewing machine 1 includes the bed 11, the pillar 12, the arm 13, and a head 14. The bed 11 is a base of the sewing machine 1 extending in the left-right direction. The pillar 12 is provided upright from a right end of the bed 11. The arm 13 extends leftward from an upper end of the pillar 12 and faces the bed 11 in the upper-lower direction. The head 14 is provided at a left end of the arm 13.

[0034] A needle plate 16 is provided on an upper surface of the bed 11. The needle plate 16 is a plate that extends horizontally, that is, in a direction perpendicular to the upper-lower direction. The bed 11 and the needle plate 16 support, from below, the sewing workpiece C which is sewn by the sewing machine 1. The bed 11 accommodates a hook (not shown) below the needle plate 16. The hook accommodates a lower thread (not shown) and entwines the lower thread with an upper thread (not shown). An LCD 15 is provided on a front surface of the pillar 12. The LCD 15 displays various images. The pillar 12 accommodates a sewing machine motor (not shown). The sewing machine motor drives the hook and a needle bar 6. The arm 13 accommodates the upper thread and a main drive shaft (not shown). The upper thread is guided in the arm 13 toward a sewing needle 7. The main drive shaft extends in the left-right direction and is rotationally driven by the sewing machine motor.

[0035] The head 14 is provided with the needle bar 6 and the presser bar 8. The needle bar 6 extends in the upper-lower direction. The lower end of the needle bar 6 protrudes downward from the lower end of the head 14. The sewing needle 7 is detachably attached to the lower end of the needle bar 6. The needle bar 6 is driven to reciprocate in the upper-lower direction by the rotation of the main drive shaft. The sewing machine 1 forms stitches on the sewing workpiece C by driving the needle bar 6 and the hook. The presser bar 8 extends in the upper-lower direction at a position rearward of the needle bar 6. The lower end of the presser bar 8 protrudes downward from the lower end of the head 14. The lower end of the presser bar 8 is located above the needle plate 16. The movement detector 2 is attached to the lower end of the presser bar 8.

[0036] The structure of the movement detector 2 will be described with reference to FIGS. 4 to 12. The movement detector 2 detects the movement amount of the sewing workpiece C that is disposed on the bed 11 below the presser bar 8, and outputs the detected movement amount to the sewing machine 1. The sewing machine 1 adjusts the pitch of stitches formed on the sewing workpiece C by controlling driving of the sewing machine motor based on the movement amount of the sewing workpiece C. The presser foot 5 is attachable to and detachable from the movement detector 2. Although details will be described later, the presser foot 5 contacts the sewing workpiece C from above and suppresses lifting (floating) of the sewing workpiece C (see FIG. 2). As shown in FIGS. 4 to 7, the movement detector 2 includes a housing 20, the sensor 18 (see FIG. 9), a cable 9, a lock plate 70, a slider 80, and a mount body 91. The housing 20 has a rectangular parallelepiped shape longer in the front-rear direction than in the left-right direction. The housing 20 accommodates the sensor 18, the lock plate 70, and the slider 80.

[0037] The housing 20 includes an upper wall 25, a lower wall 26, and a peripheral wall 27. Each of the upper wall 25 and the lower wall 26 extends horizontally. In a state where the movement detector 2 is attached to the presser bar 8 of the sewing machine 1, the lower wall 26 is separated upward from the needle plate 16 with a slight gap therebetween (refer to FIG. 2). The sewing workpiece C is disposed between the lower wall 26 and the needle plate 16, that is, the lower wall 26 is located above the sewing workpiece C supported by the needle plate 16.

[0038] The peripheral wall 27 extends in the upper-lower direction between a peripheral edge of the upper wall 25 and a peripheral edge of the lower wall 26. The peripheral wall 27 includes a left wall 21, a right wall 22, the front wall 23, and a rear wall 24. The left wall 21 and the right wall 22 extend perpendicularly to the left-right direction and are arranged in the left-right direction. The front wall 23 and the rear wall 24 extend perpendicularly to the front-rear direction and are arranged in the front-rear direction. The upper wall 25 faces upward, the lower wall 26 faces downward, the left wall 21 faces leftward, the right wall 22 faces rightward, the front wall 23 faces forward, and the rear wall 24 faces rearward. The front wall 23 is spaced from the sensor 18 in a detachment direction in which the presser foot 5 is detached.

[0039] The housing 20 includes an upper housing 30 and a lower housing 40. The upper housing 30 is an upper portion of the housing 20, and the lower housing 40 is a lower portion of the housing 20. The housing 20 is configured by stacking the upper housing 30 on the lower housing 40 from above.

[0040] The structure of the lower housing 40 will be described with reference to FIGS. 4 to 6. The lower housing 40 includes a lower wall 46, an inclined wall 48, a middle wall 47, a left wall 41, a right wall 42, a front wall 43, and a rear wall 44. The lower wall 46, the inclined wall 48, and the middle wall 47 are connected in this order from the front. Each of the lower wall 46 and the middle wall 47 extends horizontally. The middle wall 47 is located above the lower wall 46. The inclined wall 48 connects the rear end of the lower wall 46 and the front end of the middle wall 47, and extends rearward and upward. A sensor opening 49 is formed in the lower wall 46 to open through the lower wall 46 in the upper-lower direction. The lower wall 46 constitutes the lower wall 26 of the housing 20.

[0041] The left wall 41 extends upward from the left ends of the lower wall 46, the inclined wall 48, and the middle wall 47. The right wall 42 extends upward from the right ends of the lower wall 46, the inclined wall 48, and the middle wall 47. The front wall 43 extends upward from the front end of the lower wall 46. The rear wall 44 extends upward from the rear end of the middle wall 47. That is, the lower housing 40 is a box that is open upward.

[0042] The lower housing 40 accommodates a circuit board 17 (see FIG. 7) and the sensor 18 (see FIG. 9). The circuit board 17 is a plate extending horizontally. The circuit board 17 has a plate shape longer in the front-rear direction than in the left-right direction. The circuit board 17 extends from the front wall 43 to the rear wall 44 over substantially the entirety of the lower housing 40 in the front-rear direction. Various electronic components are mounted on the circuit board 17. The circuit board 17 is connected to one end of the cable 9 (see FIG. 2). Although not shown, the other end of the cable 9 is connected to the sewing machine 1.

[0043] As shown in FIG. 9, the sensor 18 is provided below the circuit board 17. The sensor 18 is located above the lower wall 46. Although not shown, the sensor 18 includes a light emission portion (not shown) and a light detection portion (not shown). The light emission portion and the light detection portion are located above the sensor opening 49. The light emission portion emits light to the sewing workpiece C in order to detect the movement amount of the sewing workpiece C. The light emission portion is, for example, an infrared light emitting diode that emits infrared light. In a state where the movement detector 2 is attached to the presser bar 8 of the sewing machine 1, the light emission direction D of the light emission portion is downward. The emitted light passes through the sensor opening 49, reaches the sewing workpiece C, and is reflected. The light reflected by the sewing workpiece C passes through the sensor opening 49. The light detection portion detects light reflected from the sewing workpiece C and converts the light into an electric signal. The light detection portion is, for example, an infrared imaging element that detects infrared rays. The sensor 18 periodically emits light to the sewing workpiece C by the light emission portion, and detects the movement amount of the sewing workpiece C per unit time. The movement detector 2 outputs the movement amount of the sewing workpiece C per unit time to the sewing machine 1 via the cable 9.

[0044] As shown in FIG. 7, a wall 33 is provided at the upper end of the front wall 43. The wall 33 extends horizontally. The front end of the wall 33 is located at substantially the same position as the front end of the front wall 43 in the front-rear direction. The rear end of the wall 33 is located rearward of the rear end of the front wall 43 (see FIG. 9) and forward of a rod 92 (see FIG. 8). The left end of the wall 33 is located between the center of the front wall 43 in the left-right direction and the left end of the front wall 43. The right end of the wall 33 is located between the center of the front wall 43 in the left-right direction and the right end of the front wall 43. The wall 33 constitutes a lower end of an opening end 37 that defines an insertion opening 29 described later. The wall 33 and the front wall 43 constitute the front wall 23 of the housing 20.

[0045] Recesses 331 and 332 are formed in the wall 33. The recesses 331 and 332 are portions recessed downward from the upper surface of the wall 33. The recess (groove) 331 extends rearward from the front end of the wall 33. The rear end of the recess 331 is located between the center of the wall 33 in the front-rear direction and the rear end of the wall 33. The recess 331 is located between the center of the wall 33 in the left-right direction and the left end of the wall 33. The recess 331 is located leftward of the center of the lower housing 40 in the left-right direction. The recess 331 is located on an insertion path of the presser foot 5 (see FIG. 8), and a protrusion 55A of the presser foot 5 described later fits to the recess 331. The recess 332 is located at the right rear end of the wall 33. The front end of the recess 332 extends in the left-right direction and is located at substantially the center of the wall 33 in the front-rear direction. The left end of the recess 332 extends in the front-rear direction and is located between the recess 331 and the right end of the wall 33.

[0046] The lock plate 70 is provided above the circuit board 17. The lock plate 70 is a leaf spring and is elastically deformable in the upper-lower direction. The material of the lock plate 70 is, for example, a metal such as phosphor bronze. The lock plate 70 locks the presser foot 5 (see FIG. 10). The slider 80 is provided above the lock plate 70. The slider 80 functions as a lock release mechanism for releasing the lock of the presser foot 5 by the lock plate 70.

[0047] The structures of the lock plate 70 and the slider 80 will be described with reference to FIGS. 9 to 12. The lock plate 70 includes a base portion 71, extending portions 72 and 73, a fitting portion 74, and a protruding portion 75. The base portion 71 is a plate that extends horizontally and is longer in the front-rear direction than in the left-right direction. An opening 711 is formed in a front end portion of the base portion 71 to open through the base portion 71 in the upper-lower direction. An opening 712 is formed in a rear end portion of the base portion 71 to open through the base portion 71 in the upper-lower direction. The base portion 71 is fixed to the lower housing 40 by screws (not shown) at a position above the circuit board 17 through the openings 711 and 712. The base portion 71 is located at substantially the same position as the bottom surface of the recess 332 in the upper-lower direction.

[0048] The extending portion 72 is a plate extending upward from the front end of the base portion 71. The upper end of the extending portion 72 is located at substantially the same position as the upper end of the wall 33 in the upper-lower direction. The extending portion 73 is a plate extending forward from the upper end of the extending portion 72. The extending portion 73 extends horizontally, and the size of the extending portion 73 in the front-rear direction is larger than the size of the extending portion 73 in the left-right direction. The front end of the extending portion 73 is located rearward of the front end of the recess 332 and upward of the bottom of the recess 332. A front end portion of the extending portion 73 is located at a position overlapping the recess 332 in a plan view.

[0049] A cutout 79 is formed in the extending portion 73. The cutout 79 is a portion of the extending portion 73 that is cut out rightward from the left end of the extending portion 73. The right end of the cutout 79 is located at substantially the center of the extending portion 73 in the left-right direction. The front end of the cutout 79 is located between the center of the extending portion 73 in the front-rear direction and the front end of the extending portion 73. The front end of the cutout 79 is located at a position overlapping the recess 332 in a plan view, and is located at substantially the same position as the rear end of the recess 331 in the front-rear direction. The rear end of the cutout 79 is located substantially at the center of the extending portion 73 in the front-rear direction. The rear end of the cutout 79 is located at substantially the same position as the rear end of the wall 33 in the front-rear direction.

[0050] The fitting portion 74 is a plate shape that is bent in a protruding shape that protrudes upward with respect to the extending portion 73 as a whole. The fitting portion 74 includes an inclined portion 741 and an extending portion (horizontal portion) 742. The inclined portion 741 extends rearward and upward from an edge of the extending portion 73 that defines the front end of the cutout 79. The extending portion 742 extends rearward from the rear upper end of the inclined portion 741. The fitting portion 74 is located on the insertion path of the presser foot 5 (see FIG. 7), and fits to an opening 54A of the presser foot 5 described later.

[0051] The protruding portion 75 is a plate that is bent in a protruding shape protruding upward from the upper surface of the extending portion 73. The protruding portion 75 is spaced rearward from the fitting portion 74. The protruding portion 75 has extending portions (inclined portions) 751 and 752. The extending portion 751 extends forward and upward from an edge of the extending portion 73 that defines the rear end of the cutout 79. The front upper end of the extending portion 751 is located at substantially the same position as the upper end of the extending portion 742 in the upper-lower direction. The extending portion 752 extends forward and downward from the front upper end of the extending portion 751. The front lower end of the extending portion 752 is located at substantially the same position as the extending portion 73 in the upper-lower direction.

[0052] The lock plate 70 extends horizontally as a whole. In the lock plate 70, the base portion 71 is fixed to the upper housing 30, whereas the extending portion 73 forms a free end that is not fixed to a component other than the lock plate 70. Thus, when a load is applied to the extending portion 73 from above, the extending portion 73 is elastically deformable, and thus bends downward via the extending portion 72 with the base portion 71 as a support.

[0053] As shown in FIGS. 9 to 12, the slider 80 includes a base portion 81, a lever 82, plates 83 and 84, and a compression coil spring 89. The base portion 81 is provided on the left side of the base portion 71. The base portion 81 has a box shape longer in the front-rear direction than in the left-right direction. An opening 86 and a cutout 87 are formed in the base portion 81. The opening 86 is formed to open the base portion 81 forward. The cutout 87 is formed to cut out the upper wall of the base portion 81 rearward from the front end of the upper wall of the base portion 81.

[0054] The compression coil spring 89 extends in the front-rear direction and is accommodated in the base portion 81. The rear end of the compression coil spring 89 is connected to the rear wall of the base portion 81. The front end of the compression coil spring 89 is connected to a protrusion 28 described later. The base portion 81 is always urged rearward by the compression coil spring 89.

[0055] The lever 82 protrudes upward from a rear upper end of the base portion 81. An upper end of the lever 82 is exposed to the upper side of the housing 20 from a slider opening 38 described later (see FIG. 4). The plate 83 protrudes forward from the front end of the base portion 81. The plate 83 extends longer in the front-rear direction than in the left-right direction in horizontal directions. The plate 83 is located at substantially the center of the base portion 81 in the upper-lower direction. In a state where the presser foot 5 is attached to the movement detector 2, the plate 83 is located rearward of an insertion plate 53A described later.

[0056] The plate 84 protrudes rightward from the right end of the plate 83. The plate 84 extends longer in the front-rear direction than in the left-right direction in horizontal directions. The plate 84 is located rearward of the protruding portion 75. The rear end of the plate 84 is located at substantially the same position as the rear end of the plate 83 in the front-rear direction. The front end of the plate 84 is at the same position as the front end of the plate 83 in the front-rear direction. Hereinafter, the plate 83 and the plate 84 are collectively referred to as a slider wall 85. The slider wall 85 is located above the extending portion 73, and is located at substantially the same position as the protruding portion 75, the fitting portion 74, and the insertion plate 53A in the upper-lower direction.

[0057] The slider 80 is not fixed to the housing 20, and is slidable in the front-rear direction while being guided by the slider opening 38. The slider wall 85 slides in the front-rear direction inside the housing 20. The base portion 81 and the slider wall 85 of the slider 80, which slide in the front-rear direction inside the housing 20, are collectively referred to as a slider plate 88. The slider plate 88 extends horizontally as a whole.

[0058] The structure of the upper housing 30 will be described with reference to FIGS. 4 to 6 and 9. The upper housing 30 includes an upper wall 35, a left wall 31, a right wall 32, a rear wall 34, a front wall 39, and the protrusion 28. The upper wall 35 extends longer in the front-rear direction than in the left-right direction in horizontal directions. The front end of the upper wall 35 is located forward of the front end of the front wall 23. The upper wall 35 constitutes the upper wall 25 of the housing 20.

[0059] The left wall 31 extends downward from the left end of the upper wall 35. The right wall 32 extends downward from the right end of the upper wall 35. The rear wall 34 extends downward from the rear end of the upper wall 35. The front wall 39 extends downward from the front end of the upper wall 35. That is, the upper housing 30 is a box that is open downward. The left wall 31 and the left wall 41 constitute the left wall 21 of the housing 20. The right wall 32 and the right wall 42 constitute the right wall 22 of the housing 20. The rear wall 34 and the rear wall 44 constitute the rear wall 24 of the housing 20.

[0060] The protrusion 28 protrudes downward from the upper wall 35. The lower end of the protrusion 28 is located between the lower end of the upper housing 30 and the center of the upper housing 30 in the upper-lower direction. Although not shown, the protrusion 28 is inserted into the base portion 81 via the cutout 87. The protrusion 28 is connected to the front end of the compression coil spring 89 inside the base portion 81. The protrusion 28 is located at substantially the center of the upper wall 35 in the left-right direction and the front-rear direction.

[0061] The upper wall 35 is formed with the slider opening 38, a cable opening 98, and a shaft opening (not shown). The slider opening 38 is formed through the upper wall 35 in the upper-lower direction. The slider opening 38 extends in the front-rear direction. The front end of the slider opening 38 is located between the center of the upper wall 35 in the front-rear direction and the rear end of the upper wall 35. The rear end of the slider opening 38 is located at substantially the rear end of the upper wall 35. The lever 82 is inserted through the slider opening 38, and the slider opening 38 guides the slider 80 to slide in the front-rear direction.

[0062] The cable opening 98 is formed through the left rear end of the upper wall 35 in the upper-lower direction. The cable 9 is inserted through the cable opening 98. The shaft opening is formed through a left end portion of the upper wall 35 in the upper-lower direction. The shaft opening is located between the front end of the upper wall 35 and the center of the upper wall 35 in the front-rear direction. The rod 92 protrudes above the upper wall 35 through the shaft opening.

[0063] As shown in FIG. 8, the rod 92 is fixed to the upper housing 30. The rod 92 is located between the center of the housing 20 in the front-rear direction and the front end of the housing 20. The rod 92 is located between the center of the housing 20 in the left-right direction and the left end of the housing 20.

[0064] The mount body 91 is provided at the upper wall 35. As shown in FIG. 8, the mount body 91 includes a lower wall 95, an upper wall 94, and a mount wall 93. The lower wall 95 and the upper wall 94 extend perpendicularly to the upper-lower direction. The lower wall 95 is formed with an opening 97 that is formed through the lower wall 95 in the upper-lower direction. The upper wall 94 is formed with an opening 96 that is formed through the upper wall 94 in the upper-lower direction. The opening 96 and the opening 97 are arranged in the upper-lower direction. The rod 92 is inserted through the openings 96 and 97 and fixed to the lower wall 95 and the upper wall 35.

[0065] As shown in FIGS. 4 to 6 and 9, the mount wall 93 extends in the upper-lower direction between the right end of the lower wall 95 and the right end of the upper wall 94. The mount wall 93 is located at substantially the center of the upper wall 35 in the left-right direction. The front end of the mount wall 93 is attached to the presser bar 8. The movement detector 2 is mounted to the sewing machine 1 by fixing the mount wall 93 of the mount body 91 to the presser bar 8.

[0066] The lower end of the front wall 39 is located at substantially the same position as the upper end of the front wall 43 in the upper-lower direction. The front end of the upper wall 35 is located forward of the front end of the front wall 23, and thus the front end of the front wall 39 is located forward of the front end of the front wall 23. The rear end of the front wall 39 is located at substantially the same position as the front end of the front wall 23 in the front-rear direction.

[0067] A cutout 36 is formed in the front wall 39. The cutout 36 is recessed upward from the lower end of the front wall 39. The upper end of the cutout 36 is located between the upper end of the front wall 39 and the center of the front wall 39 in the upper-lower direction, and is located above the upper end of the wall 33. The left end of the cutout 36 is located at substantially the same position as the left end of the wall 33 in the left-right direction. The right end of the cutout 36 is located at substantially the same position as the right end of the wall 33 in the left-right direction. Thus, the insertion opening 29 is formed in the front wall 23 of the housing 20. The insertion opening 29 causes the housing 20 to open forward. The opening end 37 of the insertion opening 29 is defined by the upper end of the wall 33 and the cutout 36. The insertion opening 29 is an opening for inserting the presser foot 5 into the housing 20. A portion of the front wall 39 that protrudes forward from the upper end of the insertion opening 29 is referred to as an eaves portion 361.

[0068] The structure of the presser foot 5 will be described with reference to FIGS. 13 to 18. The presser foot 5 is available in a plurality of types, and has different shapes according to sewing operations. One selected from a plurality of types of presser feet 5 is attachable to and detachable from the movement detector 2. The plurality of types of presser feet 5 of the present embodiment include a presser foot 5A (see FIGS. 13 and 14), a presser foot 5B (see FIGS. 15 and 16), and a presser foot 5C (see FIGS. 17 and 18). The material of the presser feet 5A and 5B and portions of the presser foot 5C other than a presser plate 51C described below are metals such as aluminum alloys, for example.

[0069] As shown in FIGS. 13 and 14, the presser foot 5A includes a presser plate 51A, a connection plate 52A, and the insertion plate 53A. The presser plate 51A is perpendicular to the upper-lower direction and has a substantially circular shape in a plan view. In a state where the presser foot 5A is attached to the movement detector 2, the presser plate 51A contacts the sewing workpiece C from above, and suppresses lifting (floating) of the sewing workpiece C (refer to FIG. 2).

[0070] The connection plate 52A extends rearward and upward from the rear end of the presser plate 51A and then bends upward. A portion of the connection plate 52A extending rearward and upward is referred to as a connection portion 56A, and a portion of the connection plate 52A extending upward is referred to as an extending portion 57A. A size (width) L2 of the lower end of the connection portion 56A in the left-right direction is smaller than a size (width) L1 of the upper end of the connection portion 56A in the left-right direction. This allows the user located forward of the sewing machine 1 to easily check the state of the sewing workpiece C that is disposed below the presser plate 51A. The state of the sewing workpiece C is, for example, an interval between stitches formed on the sewing workpiece C, a direction to be sewn next, and so on.

[0071] The insertion plate 53A extends rearward from the upper end of the extending portion 57A. The insertion plate 53A is perpendicular to the upper-lower direction and has a substantially rectangular shape in a plan view. The size of the insertion plate 53A in the left-right direction is substantially the same as the size of the insertion opening 29 in the left-right direction. The size of the insertion plate 53A in the upper-lower direction is substantially the same as the size of the insertion opening 29 in the upper-lower direction (see FIG. 4). The size of the insertion plate 53A in the front-rear direction is substantially the same as the size of the wall 33 in the front-rear direction (see FIG. 10).

[0072] The insertion plate 53A is provided with the opening 54A and the protrusion 55A. The opening 54A is formed through the insertion plate 53A in the upper-lower direction. The opening 54A is located between the right end of the insertion plate 53A and the center of the insertion plate 53A in the left-right direction. The opening 54A is located between the rear end of the insertion plate 53A and the center of the insertion plate 53A in the front-rear direction. When the presser foot 5A is attached to the movement detector 2, the fitting portion 74 of the lock plate 70 is disposed on the insertion path of the opening 54A, and the opening 54A is fitted to the fitting portion 74 (see FIGS. 7 and 12).

[0073] The protrusion 55A is formed by, for example, press-molding the insertion plate 53A from above. The protrusion 55A protrudes downward from the insertion plate 53A. The protrusion 55A is located between the left end of the insertion plate 53A and the center of the insertion plate 53A in the left-right direction. The protrusion 55A is arranged with the opening 54A in the left-right direction. When the presser foot 5A is attached to the movement detector 2, the protrusion 55A fits to the recess 331 of the wall 33 (see FIG. 8).

[0074] Openings 61A and 62A are formed in the presser foot 5A. The opening 61A is formed through the presser plate 51A in the upper-lower direction and extends in the left-right direction. In a state where the presser foot 5A is attached to the movement detector 2, the opening 61A is aligned with the sewing needle 7 in the upper-lower direction. When the sewing machine 1 performs sewing, the sewing needle 7 is inserted through the opening 61A.

[0075] The opening 62A is formed by a cutout 63A, an opening 64A, and a cutout 65A. The cutout 63A is a portion of the presser plate 51A that is cut out forward from the rear end of the presser plate 51A. The cutout 63A is located at substantially the center of the presser plate 51A in the left-right direction. The opening 64A is formed through the connection plate 52A in the front-rear direction over the entirety of the connection plate 52A in the upper-lower direction. The opening 64A is located at substantially the center of the connection plate 52A in the left-right direction. The lower end of the opening 64A is continuous with the rear end of the cutout 63A. The cutout 65A is a portion of the insertion plate 53A that is cut out rearward from the front end of the insertion plate 53A. The cutout 65A is located at substantially the center of the insertion plate 53 A in the left-right direction. The front end of the cutout 65A is continuous with the upper end of the opening 64A. That is, the opening 62A is formed through the presser foot 5A in the front-rear direction over the entirety of the presser foot 5A in the upper-lower direction. In a state where the presser foot 5A is attached to the movement detector 2, the user located forward of the sewing machine 1 checks the state of the sewing workpiece C through the opening 62A (refer to FIG. 3).

[0076] As shown in FIG. 14, a center of gravity GA of the presser foot 5A is located on the insertion plate 53A. Thus, when the presser foot 5A is placed on a plate that extends horizontally, such as the needle plate 16, the presser foot 5A rotates counterclockwise in a left side view, and the rear end of the insertion plate 53A contacts the plate.

[0077] The presser feet 5B and 5C will be described mainly in terms of differences from the presser foot 5A. In the presser feet 5B and 5C, the description of the configuration having the same shape or function as the presser foot 5A will be omitted or simplified. As shown in FIGS. 15 and 16, the presser foot 5B includes a presser plate 51B, a connection plate 52B, and an insertion plate 53B.

[0078] The presser plate 51B corresponds to the presser plate 51A. The presser plate 51B is different from the presser plate 51A in that an opening 61B is formed in the presser plate 51B, a cutout corresponding to the cutout 63A is not formed, and a cutout 66B is further formed. The opening 61B corresponds to the opening 61A. The cutout 66B is a portion of the presser plate 51B that is cut out rearward from the front end of the presser plate 51B to the opening 61B. The cutout 66B is located at substantially the center of the presser plate 51B in the left-right direction.

[0079] The connection plate 52B corresponds to the connection plate 52A. The connection plate 52B includes a connection portion 56B and an extending portion 57B. The connection portion 56B corresponds to the connection portion 56A, and the extending portion 57B corresponds to the extending portion 57A. A size (width) L4 of the lower end of the connection portion 56B in the left-right direction is smaller than a size (width) L3 of the upper end of the connection portion 56B in the left-right direction. An opening 64B is formed in the connection plate 52B. The opening 64B corresponds to the opening 64A.

[0080] The insertion plate 53B corresponds to the insertion plate 53A. The insertion plate 53B is provided with an opening 54B and a protrusion 55B. The opening 54B corresponds to the opening 54A, and the protrusion 55B corresponds to the protrusion 55A. A cutout 65B is formed in the insertion plate 53B. The cutout 65B corresponds to the cutout 65A. The opening 62B of the presser foot 5B is formed by the opening 64B and the cutout 65B. A center of gravity GB of the presser foot 5B is located on the insertion plate 53B. The position of the center of gravity GB of the insertion plate 53B is substantially the same as the position of the center of gravity GA of the insertion plate 53A.

[0081] As shown in FIGS. 17 and 18, the presser foot 5C includes the presser plate 51C, a connection plate 52C, and an insertion plate 53C. The presser plate 51C is made of a transparent member. The material of the presser plate 51C is, for example, a transparent acryl resin (PMMA) and so on. The presser plate 51C is perpendicular to the upper-lower direction and has a substantially circular shape in a plan view. The diameter of the presser plate 51C is longer than the diameter of the presser plate 51A.

[0082] An opening 61C formed in the presser plate 51C corresponds to the opening 61A. The presser plate 51C is different from the presser plate 51A in that the presser plate 51C is provided with upright columns 56C and 57C, and that the presser plate 51C is not formed with a cutout corresponding to the cutout 63A. The upright column 56C is provided upright from the left rear end of the presser plate 51C. The upright column 57C is provided upright from the right rear end of the presser plate 51C. The upright columns 56C and 57C are formed with openings opened forward and upward.

[0083] The connection plate 52C extends upward from the rear end of the presser foot 5C. The connection plate 52C is not bent, unlike the connection plate 52A. The size of the lower end of the connection plate 52C in the left-right direction is longer than the size of the lower end of the connection plate 52A in the left-right direction. An opening 64C is formed in the connection plate 52C. The opening 64C corresponds to the opening 64A. A left lower plate 58C at the left lower end of the connection plate 52C is fitted into the opening opened upward of the upright column 56C. The left lower plate 58C is fixed to the upright column 56C by a screw 68C. A right lower plate 59C at the right lower end of the connection plate 52C is fitted into the opening opened upward of the upright column 57C. The right lower plate 59C is fixed to the upright column 57C by a screw 69C.

[0084] The insertion plate 53C corresponds to the insertion plate 53A. The insertion plate 53C is provided with an opening 54C and a protrusion 55C. The opening 54C corresponds to the opening 54A, and the protrusion 55C corresponds to the protrusion 55A. A cutout 65C is formed in the insertion plate 53C. The cutout 65C corresponds to the cutout 65A. An opening 62C of the presser foot 5C is formed by the opening 64C and the cutout 65C. A center of gravity GC of the presser foot 5C is located on the insertion plate 53C. The position of the center of gravity GC of the insertion plate 53C is substantially the same as the position of the center of gravity GA of the insertion plate 53A.

[0085] With reference to FIGS. 7 to 12, attachment of the presser foot 5 to the movement detector 2 and detachment of the presser foot 5 from the movement detector 2 will be described. The following describes a case where the presser foot 5A among the presser feet 5 is attached and a case where the presser foot 5A is detached. Although not described, the same applies to a case where the presser foot 5B or the presser foot 5C is attached and detached.

[0086] First, the attachment of the presser foot 5A to the movement detector 2 will be described. The movement detector 2 is mounted on the presser bar 8, and the sewing workpiece C (refer to FIG. 2) is supported by the needle plate 16. When the presser foot 5A is attached to the movement detector 2, the user places the presser foot 5A on the sewing workpiece C at a position forward of the movement detector 2. Since the center of gravity GA of the presser foot 5A is located on the insertion plate 53A, the presser foot 5A rotates counterclockwise in a left side view, and the rear end of the insertion plate 53A contacts the plate (the sewing workpiece C).

[0087] The user moves the presser foot 5A rearward toward the front wall 23 of the movement detector 2 in a posture in which the insertion plate 53A is disposed at the rear end of the presser foot 5A. The presser foot 5A passes under the sewing needle 7. At this time, since the opening 62A (refer to FIG. 3) is formed in the presser foot 5A, the connection plate 52A is unlikely to contact (interfere with) the sewing needle 7. When the insertion plate 53A of the presser foot 5A reaches the front wall 23, the user rotates the presser foot 5A clockwise in a left side view about the lower end of the connection portion 56A. The insertion plate 53A is lifted up to the insertion opening 29.

[0088] The lifted insertion plate 53A contacts the eaves portion 361 from below. Since the eaves portion 361 protrudes forward from the upper end of the opening end 37, the insertion plate 53A in contact with the eaves portion 361 is aligned with the insertion opening 29.

[0089] The insertion plate 53A is inserted rearward from the insertion opening 29. The recess 331 is formed on the insertion path of the protrusion 55A of the insertion plate 53A. Thus, the recess 331 is fitted to the protrusion 55A inserted from the front. The fitting portion 74 of the lock plate 70 is disposed on the insertion path of the insertion plate 53A. When the insertion plate 53A is inserted into the insertion opening 29, the rear end of the insertion plate 53A contacts the inclined portion 741 of the fitting portion 74 from the front. The inclined portion 741 is inclined upward toward the rear. Thus, when the insertion plate 53A presses the inclined portion 741, the extending portion 73 of the lock plate 70 is elastically deformed downward as the inclined portion 741 is pressed by the insertion plate 53A.

[0090] When the insertion plate 53A is inserted further rearward, the opening 54A is disposed above the fitting portion 74. The pressing of the insertion plate 53A against the inclined portion 741 is released, the downward elastic deformation of the extending portion 73 is released, and the fitting portion 74 fits into the opening 54A. In this way, the presser foot 5A is locked and attached to the movement detector 2.

[0091] In a state where the presser foot 5A is locked, the slider wall 85, the protruding portion 75, and the insertion plate 53A are arranged in this order from the rear on a movement path of the slider wall 85 of the slider 80 in the front-rear direction. The insertion plate 53A contacts the wall 33, and the connection plate 52A contacts the front wall 23. Even if the presser foot 5A is tried to be pulled out forward from the insertion opening 29 in a state where the presser foot 5A is locked, the extending portion 742 contacts an inside wall of the opening 54A from the front, and thus the presser foot 5A is not pulled out from the insertion opening 29.

[0092] The detachment of the presser foot 5 from the movement detector 2 will be described. When detaching the presser foot 5A from the movement detector 2, the user slides the lever 82 forward. The slider plate 88 slides forward together with the lever 82 against the urging force of the compression coil spring 89. The protruding portion 75 of the lock plate 70 is disposed on the movement path of the slider plate 88 which slides in the front-rear direction. When the slider plate 88 slides forward, the slider wall 85 contacts the extending portion 751 of the protruding portion 75 from the rear. The extending portion 751 is inclined upward toward the front. Thus, when the slider wall 85 presses the extending portion 751, the extending portion 73 of the lock plate 70 is elastically deformed downward as the extending portion 751 is pressed by the slider wall 85. As a result, the fitting (engagement) between the fitting portion 74 and the opening 54A is released, and the locked state of the presser foot 5A is released and the presser foot 5A is movable forward.

[0093] When the slider wall 85 slides further forward, the slider wall 85 contacts the rear end of the insertion plate 53A of the presser foot 5A. Since the insertion plate 53A is movable forward, the slider wall 85 pushes the insertion plate 53A forward. When the insertion plate 53A is pushed forward, the connection plate 52A is less likely to contact (interfere with) the sewing needle 7 because the opening 62A is formed in the presser foot 5A.

[0094] When the insertion plate 53A is pushed forward through the insertion opening 29, the presser foot 5A rotates counterclockwise in a left side view because the center of gravity GA of the presser foot 5A is located on the insertion plate 53A. The user moves the presser foot 5A forward. The presser foot 5A passes under the sewing needle 7, and the detachment of the presser foot 5A is completed. The position of the center of gravity GA of the presser foot 5A causes the presser foot 5 A to rotate counterclockwise in a left side view, which allows the user to easily detach the presser foot 5A due to the opening 62A.

[0095] In the above embodiment, the sewing machine 1 is an example of a sewing machine of the present disclosure. The presser bar 8 is an example of a presser bar of the present disclosure. The sewing workpiece C is an example of a sewing workpiece of the present disclosure. The movement detector 2 is an example of a movement detector of the present disclosure. The sensor 18 is an example of a sensor of the present disclosure. The housing 20 is an example of a housing of the present disclosure. The emission direction D and downward are examples of an emission direction of the present disclosure. The forward is an example of a detachment direction of the present disclosure. The front wall 23 is an example of a wall surface of the present disclosure. The presser feet 5, 5A, 5B, and 5C are examples of a presser foot of the present disclosure. The insertion opening 29 is an example of an insertion opening of the present disclosure. The lock plate 70 is an example of a lock plate of the present disclosure. The fitting portion 74 is an example of a fitting portion of the present disclosure. The openings 54A, 54B, and 54C are examples of a fitted portion of the present disclosure. The horizontal direction is an example of an emission surface direction. The rearward is an example of an attachment direction of the present disclosure. The upward is an example of a reflection direction of the present disclosure, an example of a first approach direction of the present disclosure, and an example of a second approach direction of the present disclosure. The front-rear direction is an example of a slide direction of the present disclosure. The slider 80 is an example of a slider of the present disclosure. The slider opening 38 is an example of a slider opening of the present disclosure. The slider plate 88 is an example of a slider plate of the present disclosure. The lever 82 is an example of a lever of the present disclosure. The downward is an example of a separation direction of the present disclosure. The protruding portion 75 is an example of a protruding portion of the present disclosure. The eaves portion 361 is an example of an eaves portion of the present disclosure. The inclined portion 741 is an example of an inclined portion of the present disclosure. The recess 331 is an example of a guide portion of the present disclosure. The protrusions 55A, 55B, and 55C are examples of a guided portion of the present disclosure. The insertion plates 53A, 53B, and 53C are examples of an insertion plate of the present disclosure. The presser plates 51A, 51B, and 51C are examples of a presser plate of the present disclosure. The openings 62A, 62B, and 62C are examples of a connection plate opening of the present disclosure. The connection plates 52A, 52B, and 52C are examples of a connection plate of the present disclosure. The left-right direction is an example of a width direction. The connection portions 56A and 56B are examples of a connection portion of the present disclosure. The bed 11 is an example of a bed of the present disclosure. The sewing system 100 is an example of a sewing system of the present disclosure. The needle bar 6 is an example of a needle bar of the present disclosure.

[0096] In the embodiment described above, the main operations and effects of the movement detector 2 and the sewing system 100 including the movement detector 2 will be described. The movement detector 2 of the sewing system 100 includes the sensor 18, the housing 20, and the insertion opening 29. The sensor 18 emits light toward the sewing workpiece C and detects light reflected from the sewing workpiece C in order to detect the movement amount of the sewing workpiece C. The housing 20 accommodates the sensor 18. The insertion opening 29 is formed in the front wall 23 of the housing 20. The presser foot 5 is inserted through the insertion opening 29. The movement detector 2 locks the presser foot 5 inserted into the housing 20 through the insertion opening 29. In the movement detector 2, the presser foot 5 is attached and detached in the front-rear direction through the insertion opening 29 formed in the front of the housing 20. Thus, the presser foot 5 is easily attached to and detached from the housing 20 of the movement detector 2, compared with a case where the presser foot 5 is attached and detached in the upper-lower direction.

[0097] The movement detector 2 further includes the lock plate 70 accommodated in the housing 20. The lock plate 70 includes the fitting portion 74. The fitting portion 74 has a protruding shape with respect to the extending portion 73. The fitting portion 74 fits into the opening 54A (recess) formed in the presser foot 5A. The presser foot 5 is easily attached to the lock plate 70 of the movement detector 2 by fitting the fitting portion 74 into the opening 54A.

[0098] In the movement detector 2, the lock plate 70 extends horizontally (that is, perpendicularly to the upper-lower direction) as a whole. Compared with a case where the lock plate 70 extends also in the upper-lower direction, the lock plate 70 of the movement detector 2 reduces the size of the housing 20 in the upper-lower direction.

[0099] The movement detector 2 further includes the slider opening 38 and the slider 80. The slider opening 38 is formed in the upper wall 25 of the housing 20 and extends in the front-rear direction. The slider 80 is supported so as to be slidable in the front-rear direction with respect to the housing 20. The slider 80 has the slider plate 88 and the lever 82. The slider plate 88 extends horizontally. The lever 82 is provided on the base portion 81 of the slider plate 88, and is exposed above the housing 20 through the slider opening 38. The lock plate 70 is a leaf spring. The lock plate 70 further has the protruding portion 75. The protruding portion 75 is disposed on the path of the slider 80 sliding in the front-rear direction, and protrudes upward from the extending portion 73 toward the slider plate 88. The protruding portion 75 includes the extending portion 751 inclined with respect to the front-rear direction. When the slider 80 slides forward, the slider wall 85 of the slider plate 88 contacts the extending portion 751 of the protruding portion 75 from the rear, and the extending portion 73 of the lock plate 70 is elastically deformed downward to release the fitting (engagement) between the fitting portion 74 and the opening 54A. The user slides the slider 80 forward in a state where the presser foot 5 is locked, thereby releasing the fitting (engagement) between the fitting portion 74 and the opening 54A. Thus, in the movement detector 2, the presser foot 5 is easily detached from the housing 20. The lever 82 is exposed through the slider opening 38 above the housing 20. When stitches are formed on a large sewing workpiece C, a portion of the sewing workpiece C on which sewing is not performed may be rounded at the rear of the housing 20 (refer to FIG. 2). For example, in a case where a lever is exposed to the rear of the housing 20, there is a possibility that the lever contacts (interferes with) the rounded portion of the sewing workpiece C. In contrast, the lever 82 of the movement detector 2 is exposed through the slider opening 38 above the housing 20, and thus, the movement detector 2 suppresses contact (interference) of the lever 82 with the sewing workpiece C.

[0100] In the movement detector 2, the protruding portion 75 is disposed rearward of the presser foot 5 in a locked state on the movement path of the slider 80 in the front-rear direction. When the slider 80 slides forward in a state where the presser foot 5 is locked, the slider plate 88 contacts the protruding portion 75 and the presser foot 5A in this order. The slider plate 88 pushes forward the presser foot 5 which becomes movable forward by releasing the fitting (engagement) between the fitting portion 74 and the opening 54A. By sliding the slider 80 forward, the fitting (engagement) between the fitting portion 74 and the opening 54A is released, and the slider plate 88 pushes the presser foot 5 forward toward the insertion opening 29. Thus, the protruding portion 75 of the movement detector 2 enables the presser foot 5 to be easily detached from the housing 20.

[0101] In the movement detector 2, the eaves portion 361 is provided at the upper end of the insertion opening 29 in the housing 20. The eaves portion 361 protrudes forward from the upper end of the insertion opening 29. A member other than the movement detector 2, such as the needle bar 6, may be provided forward of the housing 20. In this case, in order to avoid contact (interference) with the other member, the presser foot 5 may be aligned with respect to the insertion opening 29 from below. Since the caves portion 361 is provided at the upper end of the insertion opening 29, when the presser foot 5 contacts the eaves portion 361 from below, the presser foot 5 is aligned (positioned) with respect to the insertion opening 29. Thus, the eaves portion 361 of the movement detector 2 enables the presser foot 5 to be easily aligned with respect to the insertion opening 29.

[0102] In the movement detector 2, the lock plate 70 is a leaf spring. The lock plate 70 further includes the inclined portion 741 inclined with respect to the front-rear direction. The inclined portion 741 is disposed on the insertion path of the presser foot 5. When the presser foot 5 is inserted rearward from the insertion opening 29, the presser foot 5 contacts the inclined portion 741 from the front. As a result, the extending portion 73 of the lock plate 70 is elastically deformed downward as the inclined portion 741 is pressed by the presser foot 5. When the presser foot 5 is inserted further rearward, the fitting portion 74 fits into the opening 54A. When the presser foot 5 is inserted rearward from the insertion opening 29, the presser foot 5 contacts and slides on the inclined portion 741, and the lock plate 70 is elastically deformed downward as the inclined portion 741 is pressed by the presser foot 5. When the presser foot 5 is inserted further rearward, the fitting portion 74 fits into the opening 54A and the presser foot 5 is locked. In this way, in the movement detector 2, the presser foot 5 is attached to the housing 20 simply by inserting the presser foot 5 rearward from the insertion opening 29. Thus, the lock plate 70 of the movement detector 2 enables the presser foot 5 to be easily attached to the housing 20.

[0103] In the movement detector 2, the fitting portion 74 has a protruding shape that protrudes upward from the extending portion 73 toward the presser foot 5 in a state where the presser foot 5 is inserted into the housing 20. The fitting portion 74 fits into the opening 54A which is recessed with respect to the insertion plate 53A of the presser foot 5. Since the fitting portion 74 protrudes toward the presser foot 5, the fitting portion 74 is easily fitted into the opening 54A by the lock plate 70 which is elastically deformed. Thus, the fitting portion 74 of the movement detector 2 enables the presser foot 5 to be easily attached to the housing 20.

[0104] The movement detector 2 further includes the recess 331 having a recessed shape (groove shape). The recess 331 is disposed on the insertion path of the presser foot 5. The recess 331 is fitted with the protrusion 55A of the presser foot 5 inserted from the front. When the presser foot 5 is inserted into the housing 20 through the insertion opening 29, the recess 331 is fitted with the protrusion 55A to guide the insertion of the presser foot 5. Thus, the recess 331 of the movement detector 2 suppresses the presser foot 5 being inserted into the housing 20 in a posture different from the correct posture. For example, the posture of the presser foot 5 different from the correct posture is a posture in which the presser foot 5 is rotated by 180 degrees in a front view.

[0105] The movement detector 2 includes the sensor 18, the housing 20, and the insertion opening 29. The sensor 18 emits light toward the sewing workpiece C and detects light reflected from the sewing workpiece C in order to detect the movement amount of the sewing workpiece C. The housing 20 accommodates the sensor 18. The insertion opening 29 is formed in the front wall 23 of the housing 20. The presser foot 5A is inserted into the insertion opening 29. The presser foot 5A includes the insertion plate 53A, the presser plate 51A, and the connection plate 52A. The insertion plate 53A is inserted into the housing 20 from the insertion opening 29. The presser plate 51A is disposed below and forward of the insertion plate 53A and extends in the front-rear direction. The connection plate 52A extends downward from the insertion plate 53A and is connected to the presser plate 51A. The connection plate 52A is formed with the opening 62A extending downward from the insertion plate 53A. The movement detector 2 locks the insertion plate 53A inserted into the housing 20 from the insertion opening 29. A member other than the movement detector 2, such as the needle bar 6, may be provided forward of the housing 20. When the insertion plate 53A is detached forward from the insertion opening 29 or the insertion plate 53A is attached rearward from the insertion opening 29, the presser foot 5 may contact (interfere with) the other member. The opening 62A is formed in the connection plate 52A. Thus, even when the other member is provided forward of the housing 20, the housing 20 of the movement detector 2 suppresses contact (interference) between the presser foot 5 and the other member.

[0106] In the movement detector 2, the connection plate 52A includes the connection portion 56A connected to the presser plate 51A. The size L2 of the lower end of the connection portion 56A in the left-right direction is smaller than the size LI of the upper end of the connection portion 56A in the left-right direction. Thus, the connection plate 52A of the movement detector 2 makes it easier for the user to visually recognize the state of the sewing workpiece C that is disposed below the presser plate 51A, compared with a case where the size L2 is not smaller than the size L1.

[0107] While the present disclosure has been described in conjunction with various example structures outlined above and illustrated in the figures, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or that may be presently unforeseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the example embodiments of the disclosure, as set forth above, are intended to be illustrative of the present disclosure, and not limiting the present disclosure. Various changes may be made without departing from the spirit and scope of the disclosure. Thus, the disclosure is intended to embrace all known or later developed alternatives, modifications, variations, improvements, and/or substantial equivalents. Some specific examples of potential alternatives, modifications, or variations in the described disclosure are provided below.

[0108] A movement detector 200 of a modification will be described with reference to FIG. 19. The movement detector 200 of the modification differs from the movement detector 2 of the above embodiment in that the wall 33 is not provided, a lock plate 700 is provided instead of the lock plate 70, and a presser foot 5D is attached. In the following description, the same reference numerals are given to configurations having the same shapes or functions as those of the above-described embodiment, and the description thereof will be omitted or simplified.

[0109] The lock plate 700 differs from the lock plate 70 in that the fitting portion 74 is not provided, a cutout 790 is formed instead of the cutout 79, and an inclined portion 76 is provided. The cutout 790 corresponds to the cutout 79, and is widened in a horizontal direction by an amount corresponding to the fitting portion 74 not provided. The inclined portion 76 is a plate extending forward and downward from the front end of the extending portion 73. The left end of the inclined portion 76 is located at substantially the same position as the left end of the extending portion 73 in the left-right direction. The right end of the inclined portion 76 is located between the right end of the extending portion 73 and the center of the extending portion 73 in the left-right direction. The right end of the inclined portion 76 is located rightward of the right end of the cutout 790.

[0110] The presser foot 5D is different from the presser foot 5A in that plates 57D and 59D are provided instead of the connection plate 52A and that insertion plates 531 and 532 are provided instead of the insertion plate 53A. The plate 57D is a plate extending in the left-right direction and the upper-lower direction. The plate 57D extends longer in the left-right direction than in the upper-lower direction. The plate 59D extends downward from the right end of the plate 57D. A plate (not shown) extends downward from the left end of the plate 57D. The lower end of the plate 59D and the lower end of the plate extending downward from the left end of the plate 57D are connected to a presser plate (not shown). An opening 62D is defined by the plate 57D, the plate 59D, the plate extending downward from the left end of the plate 57D, and the presser plate. The opening 62D corresponds to the opening 62A. When the presser foot 5D is attached to the movement detector 200, the plate 57D is located forward of the front wall 43.

[0111] The insertion plates 531 and 532 extend rearward from the upper end of the plate 57D. The insertion plates 531 and 532 extend horizontally, and extend longer in the front-rear direction than in the left-right direction. The insertion plate 531 and the insertion plate 532 are symmetrical with respect to the center of the plate 57D in the left-right direction. A cutout 533 is formed in the insertion plate 531. The cutout 533 is formed by cutting out the insertion plate 531 from the left end of the insertion plate 531 to the right. The front end of the cutout 533 is located between the rear end of the insertion plate 531 and the center of the insertion plate 531 in the front-rear direction. The rear end of the cutout 533 is located between the front end of the cutout 533 and the rear end of the insertion plate 531. A portion of the insertion plate 531 that is rearward of the cutout 533 is referred to as a protrusion 535.

[0112] A cutout 534 is formed in the insertion plate 532. The cutout 534 is formed by cutting out the insertion plate 532 leftward from the right end of the insertion plate 532. The front end of the cutout 534 is located between the rear end of the insertion plate 532 and the center of the insertion plate 532 in the front-rear direction. The rear end of the cutout 534 is located between the front end of the cutout 534 and the rear end of the insertion plate 532. A portion of the insertion plate 532 that is rearward of the cutout 534 is referred to as a protrusion 536. The lower end of the protrusion 536 is located between the lower end of the inclined portion 76 and the upper end of the inclined portion 76 in the upper-lower direction. The right end of the protrusion 536 is located leftward of the right end of the cutout 790.

[0113] The presser foot 5D is attached to the movement detector 200 from the front. The protrusion 536 contacts the inclined portion 76. The protrusion 536 presses the inclined portion 76 and the extending portion 73 downward, and the inclined portion 76 and the extending portion 73 are bent downward. The protrusion 536 slides with respect to the inclined portion 76 and the extending portion 73. When the rear end of the protrusion 536 slides to a position farther rearward than the front end of the cutout 790, the front end of the cutout 534 is located forward of the front end of the inclined portion 76. The left end of the cutout 534 is located leftward of the left end of the inclined portion 76 and the left end of the extending portion 73. The rear end of the protrusion 536 is located forward of the protruding portion 75. Thus, the pressing on the inclined portion 76 and the extending portion 73 by the protrusion 536 is released, and the protrusion 536 fits into the cutout 790. Thus, the lock plate 700 locks the presser foot 5D.

[0114] Other modifications will be described. The configuration of the sensor 18 may be changed as appropriate. The sensor 18 may be configured by a red diode as a light emission portion and an imaging element that images red light as a light detection portion. The sensor 18 may be configured by a blue diode as a light emission portion and an imaging element that images blue light as a light detection portion.

[0115] The configuration of the housing 20 may be appropriately changed. The housing may be box-shaped. The housing 20 may be, for example, a rectangular parallelepiped longer in the front-rear direction than in the left-right direction.

[0116] The insertion opening 29 may be formed in the peripheral wall 27 spaced from the sensor 18 in a direction perpendicular to the emission direction D in which light is emitted from the sensor 18, and is not limited to the case where the insertion opening 29 is formed in the front wall 23. The insertion opening 29 may be provided in any of the left wall 21, the right wall 22, and the rear wall 24, for example. In this case, the presser foot 5 is attached to and detached from the insertion opening 29 in a direction perpendicular to the emission direction D. Thus, the movement detector 2 contributes to easy attachment and detachment of the presser foot 5 to and from the housing 20, compared with a case where the presser foot 5 is attached to and detached from the insertion opening 29 in the emission direction D. The position of the insertion opening 29 in the front wall 23 is not limited to the position in the above embodiment, and may be changed as appropriate. The shape of the insertion opening 29 is not limited to the shape in the above embodiment, and may be changed as appropriate.

[0117] In the above embodiment, the lower wall 46 is formed with the sensor opening 49 through which the light emitted from the sensor 18 passes. However, the lower wall 46 may have any configuration as long as the light emitted from the sensor 18 passes through the lower wall 46. For example, a transparent member such as an acrylic resin may be fitted into the sensor opening 49. The lower wall 46 may be entirely formed of a transparent member such as an acrylic resin. In this case, the sensor opening 49 may not be formed in the lower wall 46.

[0118] In the above embodiment, the fitting portion 74 has a protruding shape and fits into the opening 54A formed in the presser foot 5 and having a recessed shape. Alternatively, the fitting portion 74 may have a recessed shape and fit to a fitted portion provided on the presser foot 5 and having a protruding shape. In this case, an opening, a cutout, and so on that penetrates the extending portion 73 in the upper-lower direction, like the opening 54A of the presser foot 5, is also referred to as the fitting portion 74 having a recessed shape. The opening 54A of the presser foot 5 may be changed as appropriate in accordance with the fitting portion 74. For example, the presser foot 5 may have a recess that is recessed upward from the lower surface of the insertion plate 53A and is fitted with the fitting portion 74, instead of the opening 54A.

[0119] The position and shape of the fitting portion 74 may be changed as appropriate as long as the fitting portion 74 fits into the opening 54A. For example, the presser foot 5 may include a protrusion protruding rightward from the right end of the insertion plate 53A, and the cutout 79 of the lock plate 70 may be fitted with the protrusion from below. The cutout 79 may be fitted with the protrusion from the right side. In other words, the direction in which the fitting portion 74 fits into the opening 54A is not limited to the upward direction, and may be changed as appropriate.

[0120] The lock plate 70 is not limited to extending horizontally as a whole. For example, the lock plate 70 may extend in a direction perpendicular to the left-right direction or in a direction perpendicular to the front-rear direction.

[0121] The configuration of the slider 80 may be changed as appropriate. The slider plate 88 may be appropriately changed in configuration. The slider plate 88 may extend horizontally as a whole. For example, the slider plate 88 may not include the plates 83 and 84, and the box-shaped base portion 81 may extend forward from the base portion 81 of the embodiment. The lever 82 may be provided on the slider plate 88, for example, on the plate 83 or the plate 84. The lever 82 may be provided on any one of the left wall, the right wall, and the upper wall of the base portion 81. The lever 82 may be exposed from the left wall 21 or the right wall 22. The slider 80 may not include the compression coil spring 89. The slider 80 may include a tension coil spring for urging the slider plate 88 rearward, instead of the compression coil spring 89.

[0122] The slider opening 38 is not limited to extending parallel to the front-rear direction, and may extend, for example, inclined with respect to the front-rear direction. The slider opening 38 may extend in the front-rear direction and may extend in an arc shape that is convex to the right or to the left. The slider opening 38 may be wave-shaped or zigzag-shaped.

[0123] The lock plate 70 is not limited to a leaf spring and may not be elastically deformed. In this case, the lock plate 70 may move in translation or rotate relative to the presser foot 5, and whereby the fitting portion 74 may fit into the opening 54A.

[0124] The lock plate 70 may not have the protruding portion 75. The configuration of the protruding portion 75 may be changed as appropriate. The extending portion 751 of the protruding portion 75 may extend upward perpendicularly from the extending portion 73. The extending portion 751 may extend forward and upward from the extending portion 73 while being convex forward or rearward. The front upper end of the extending portion 751 may not be located at substantially the same position as the upper end of the extending portion 742 in the upper-lower direction, and may be located above or below the upper end of the extending portion 742. The protruding portion 75 may not include the extending portion 752. The extending portion 752 is not limited to extending forward and downward from the front upper end of the extending portion 751, and may extend forward and upward from the front upper end of the extending portion 751, may extend forward from the front upper end of the extending portion 751, or may extend upward or downward from the front upper end of the extending portion 751. The front lower end of the extending portion 752 may not be located at substantially the same position as the extending portion 73 in the upper-lower direction, and may be located above or below the upper end of the extending portion 73. The protruding portion 75 may not be disposed on the movement path of the slider 80. The protruding portion 75 is not limited to being disposed on the movement path of the slider plate 88, and may be disposed on the movement path of the lever 82, for example.

[0125] The fitting (engagement) between the fitting portion 74 and the opening 54A may be released when the slider 80 slides rearward. In this case, the extending portion 751 may extend rearward and upward from the extending portion 73.

[0126] In a state where the presser foot 5 is locked, the positional relationship between the protruding portion 75 and the insertion plate 53A may be changed as appropriate. The protruding portion 75 may be disposed forward of the presser foot 5 in a state where the presser foot 5 is locked.

[0127] When the slider plate 88 slides forward in a state where the presser foot 5 is locked, the slider plate 88 may not contact the protruding portion 75 and the presser foot 5 in this order, but may contact the presser foot 5 and the protruding portion 75 in this order. When the slider plate 88 slides forward in a state where the presser foot 5 is locked, the slider plate 88 may not push the presser foot 5 forward toward the insertion opening 29. In the above embodiment, the slider wall 85 contacts the protruding portion 75 and the presser foot 5. However, for example, a portion of the slider plate 88 other than the slider wall 85, such as the base portion 81, may contact at least the protruding portion 75 or the presser foot 5. The front end of the plate 83 may not be located at the same position as the front end of the plate 84 in the front-rear direction. For example, the front end of the plate 83 may be located forward of the front end of the plate 84. In this case, the slider plate 88 may contact the protruding portion 75 and the presser foot 5 in this order, or may not contact the protruding portion 75 and the presser foot 5 in this order. In this way, the present disclosure is not limited to that at least the protruding portion 75 or the presser foot 5 contacts the front end of the slider plate 88. At least the protruding portion 75 or the presser foot 5 may contact a portion of the slider 80 other than the slider plate 88, such as the lever 82.

[0128] The eaves portion 361 may not be provided at the housing 20. The eaves portion 361 may protrude forward from the upper end of the insertion opening 29, and the configuration thereof may be appropriately changed. The eaves portion 361 may protrude forward and upward or forward and downward from the upper end of the insertion opening 29. The eaves portion 361 may protrude forward and downward while being convex forward or rearward, for example. In the embodiment described above, the cutout 36 is formed to cut out upward from the lower end of the front wall 39, and the cutout 36 defines the eaves portion 361. With this configuration, when the insertion plate 53A is lifted and positioned with respect to the insertion opening 29, the insertion plate 53A is guided by the cutout 36, and is positioned with respect to the insertion opening 29 in the left-right direction. However, the eaves portion 361 protruding forward from the upper end of the insertion opening 29 may be provided at the housing 20, without forming the cutout 36 in the front wall 39. In this case, the insertion plate 53A is positioned with respect to the insertion opening 29 in the upper-lower direction by the eaves portion 361.

[0129] In the above embodiment, the inclined portion 741 of the fitting portion 74 is inclined with respect to the front-rear direction, and when the presser foot 5 is inserted from the insertion opening 29, the presser foot 5 contacts the inclined portion 741, and the lock plate 70 is elastically deformed downward as the inclined portion 741 is pressed by the presser foot 5. However, the inclined portion 741 is not limited to being provided at the fitting portion 74. The inclined portion 741 may be provided at the front end of the extending portion 73 on the insertion path of the presser foot 5, instead of the fitting portion 74, for example. In this case, the inclined portion 741 extends forward and downward from the front end of the extending portion 73. When the presser foot 5 is inserted from the insertion opening 29, the presser foot 5 contacts the inclined portion 741 provided at the front end of the extending portion 73, and the lock plate 70 is elastically deformed downward as the inclined portion 741 is pressed by the presser foot 5. In this case, the shape of the fitting portion 74 may be changed as appropriate, and the presser foot 5 may or may not contact the fitting portion 74.

[0130] The inclined portion 741 may extend upward or downward perpendicularly from the extending portion 73. The inclined portion 741 may extend forward and upward from the extending portion 73 while being convex forward or rearward.

[0131] In the above embodiment, when the presser foot 5 is inserted from the insertion opening 29, the recess (groove) 331 formed on the wall 33 guides the protrusion 55A provided on the insertion plate 53A. Alternatively, a protrusion protruding upward from the upper surface of the wall 33 may guide a recess (groove) formed in the insertion plate 53A. The shape of the recess 331 may be changed as appropriate. The recess 331 may be recessed rearward from the front surface of the wall 33 and may extend in the upper-lower direction over the entirety of the front surface of the wall 33 in the upper-lower direction. The recess 331 is not limited to the case where the recess 331 is provided at the lower end of the opening end 37, and may be provided at the left end, the right end, or the upper end of the opening end 37.

[0132] The shape of the presser foot 5 may be changed as appropriate. The presser foot 5 is not limited to the shapes of the presser feet 5A, 5B, and 5C of the above embodiment, and may include presser foot 5 having a shape different from the shapes of the presser feet 5A, 5B, and 5C. Although modifications will be described below based on the function and shape of the presser foot 5A, portions of the presser feet 5B and 5C having the same function and shape as the presser foot 5A may be modified in the same manner as the presser foot 5A, and the description thereof will be omitted.

[0133] In the presser foot 5A, the insertion plate 53A may not be perpendicular to the upper-lower direction, and the shape may be changed as appropriate. The shape of the presser plate 51A may be changed as appropriate. The presser plate 51A may or may not contact the sewing workpiece C supported by the needle plate 16. The positional relationship of the presser plate 51A with respect to the insertion plate 53A may be changed as appropriate. For example, the presser plate 51A may be provided rearward of the insertion plate 53A or above the insertion plate 53A. The connection plate 52A may extend from the insertion plate 53A toward the presser plate 51A. The connection plate 52A may extend perpendicularly to the front-rear direction, like the connection plate 52C. The entirety of the connection plate 52A may extend to be inclined with respect to the front-rear direction. The connection plate 52A may extend in the upper-lower direction and may be convex forward or rearward.

[0134] The configuration of the opening 62A may be changed as appropriate. The opening 62A may not have at least the cutout 63A or the cutout 65A. In this case, the opening 64A may not extend from the upper end of the connection plate 52A to the lower end of the connection plate 52A. For example, the opening 64A may extend from the upper end of the connection plate 52A to the center of the connection plate 52A in the upper-lower direction. The presser foot 5A may not be formed with the opening 62A.

[0135] The shape of the connection portion 56A may be changed as appropriate. The size L2 of the connection portion 56A may be the same as the size L1 of the connection portion 56A or may be longer than the size L1.

[0136] The sewing system 100 includes the sewing machine 1 and the movement detector 2, and the configuration may be changed as appropriate. For example, the sewing system 100 may further include an embroidery frame that is attached to the sewing machine 1 and that intermittently presses the sewing workpiece C in synchronization with up-down movement of the needle bar 6.

[0137] Other modifications will be described. The configuration of the sewing machine 1 may be changed as appropriate. The sewing machine 1 may be an industrial sewing machine or a multi-needle sewing machine. The sewing machine 1 may be a chain-stitch arm sewing machine including a looper instead of a hook. The movement detector 2 and the sewing machine 1 may not be electrically connected by the cable 9. The movement detector 2 and the sewing machine 1 may communicate with each other by wireless communication.