SEWING DEVICE, WORKPIECE HOLDING JIG, AND SEWING METHOD

Abstract

A sewing device that, when interposing a workpiece-to-be-sewn between a post head and a pressing mechanism and sewing same by penetrating a machine needle therethrough, shapes the workpiece-to-be-sewn in a prescribed shape and sews same, by seating the workpiece-to-be-sewn in a workpiece holding jig having a plurality of seats arranged along a sewing line for the workpiece-to-be-sewn.

Claims

1. A sewing device for performing sewing along a certain sewing line on a workpiece-to-be-sewn in a state of the workpiece-to-be-sewn having been shaped in a certain shape, the sewing device comprising: a sewing mechanism including: a sewing machine needle configured to, by moving in a reciprocating manner, penetrate through or withdraw from the workpiece-to-be-sewn; a post bed that faces the sewing machine needle across the workpiece-to-be-sewn; and a pressing mechanism configured to press the workpiece-to-be-sewn against the post bed from a side of the sewing machine needle; a drive mechanism configured to move the sewing mechanism; and a workpiece holding jig configured to hold the workpiece-to-be-sewn, wherein the workpiece holding jig includes: a plurality of seating portions disposed in a moving direction of the sewing mechanism, each of the seating portions being configured to hold the workpiece-to-be-sewn shaped in a certain shape by the workpiece-to-be-sewn being seated on a seating surface of a certain shape; and a retraction mechanism configured to, according to a position of the sewing mechanism, retract at least one of the seating portions from the workpiece-to-be-sewn in such a manner that interference between the sewing mechanism and the seating portion is avoided.

2. The sewing device according to claim 1, wherein in a retraction region where both surfaces of the workpiece-to-be-sewn have been set adrift due to retraction of the seating portion, sewing is performed with the sewing mechanism pinching the workpiece-to-be-sewn to adjust the surface of the workpiece-to-be-sewn to a flat surface.

3. The sewing device according to claim 1, comprising a plurality of suction holes provided in the seating surface of the seating portion, wherein the workpiece-to-be-sewn is held by being sucked through the suction holes.

4. The sewing device according to claim 1, further comprising a second workpiece holding jig disposed in a position not interfering with the moving direction of the sewing mechanism, and configured to support the workpiece-to-be-sewn.

5. The sewing device according to claim 1, wherein the retraction mechanism is configured by a cylinder or cam mechanism.

6. A workpiece holding jig used in a sewing device that includes a sewing mechanism and a drive mechanism configured to move the sewing mechanism, the sewing mechanism including: a sewing machine needle configured to, by moving in a reciprocating manner, penetrate through or withdraw from a workpiece-to-be-sewn; a post bed that faces the sewing machine needle across the workpiece-to-be-sewn; and a pressing mechanism configured to press the workpiece-to-be-sewn against the post bed from a side of the sewing machine needle, the workpiece holding jig comprising: a plurality of seating portions disposed in a moving direction of the sewing mechanism, each of the seating portions being configured to hold the workpiece-to-be-sewn maintained in a certain shape by the workpiece-to-be-sewn being seated on a seating surface of a certain shape; and a retraction mechanism configured to, according to a position of the sewing mechanism, retract at least one of the seating portions from the workpiece-to-be-sewn in such a manner that interference between the sewing mechanism and the seating portion is avoided.

7. A sewing method for performing sewing along a certain sewing line on a workpiece-to-be-sewn in a state of the workpiece-to-be-sewn having been shaped in a certain shape, the sewing being performed using a sewing mechanism including: a sewing machine needle configured to, by moving in a reciprocating manner, penetrate through or withdraw from the workpiece-to-be-sewn; a post bed that faces the sewing machine needle across the workpiece-to-be-sewn; and a pressing mechanism configured to press the workpiece-to-be-sewn against the post bed from a side of the sewing machine needle, the sewing method comprising: a step of shaping the workpiece-to-be-sewn in a certain shape by the workpiece-to-be-sewn being seated on a plurality of seating portions disposed along a sewing line of the workpiece-to-be-sewn; a step of forming a retraction region where both surfaces of the workpiece-to-be-sewn have been set adrift by retracting some of the seating portions; and a step of performing sewing with the both surfaces of the workpiece-to-be-sewn being pinched by the sewing mechanism, in the retraction region of the workpiece-to-be-sewn.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0019] FIG. 1 is a schematic configuration diagram of a sewing device according to a first embodiment of the present invention;

[0020] FIG. 2 is a side view of a workpiece holding jig of FIG. 1;

[0021] FIG. 3A is a front view of immediately before retraction of a first seating portion of the workpiece holding jig of FIG. 1, and FIG. 3B is a front view showing a state where the first seating portion has retracted;

[0022] FIG. 4 is a front view of a state where a second seating portion of the workpiece holding jig has retracted;

[0023] FIG. 5 is an enlarged perspective view of a sewing portion of the sewing device of FIG. 1;

[0024] FIG. 6 is an enlarged perspective view showing dispositions of a workpiece-to-be-sewn and a seating portion thereof according to a second embodiment of the present invention;

[0025] FIG. 7A is a cross-sectional view showing a cross section taken along the line VIIA-VIIA of FIG. 6, along with an enlarged view of part thereof, and FIG. 7B is a cross-sectional view taken along the line VIIB-VIIB of FIG. 6; and

[0026] FIGS. 8A to 8C are schematic views showing a retraction mechanism according to a third embodiment, along with operation thereof.

DESCRIPTION OF EMBODIMENTS

[0027] Preferred embodiments of the present invention will be presented and described in detail below with reference to the accompanying drawings. Note that “up”, “down”, “left”, and “right” in the description below respectively correspond to upward, downward, leftward, and rightward in the drawings. However, this is an indication of directions which has been adopted for convenience in order to facilitate understanding, and does not define directions when a sewing device, a workpiece holding jig, and a sewing method are actually used.

First Embodiment

[0028] As shown in FIG. 1, a sewing device 10 according to the present embodiment includes: a workpiece holding jig 12; a sewing mechanism 14; and a conveyor robot 16 as a drive mechanism for conveying the sewing mechanism 14. The sewing mechanism 14 is fitted to a tip arm 18 of the conveyor robot 16.

[0029] As shown in FIG. 2, the workpiece holding jig 12 comprises a seating portion 20, a guide pin 22, an air cylinder 24, a vacuum generator 40, and a frame body 26. The seating portion 20 has a seating surface 20a formed in its upper portion. The seating surface 20a is formed in the same shape as a workpiece-to-be-sewn 58 (refer to FIG. 3A), in order for shape of the workpiece-to-be-sewn 58 to be maintained. Note that in the example illustrated, the seating surface 20a includes in its uppermost portion a portion which is curved at an acute angle. That seating surface 20a has a plurality of suction holes 30 formed therein. These suctions holes 30 communicate with a negative pressure passage 32 on an inside of the seating portion 20, and that negative pressure passage 32 communicates with an air hose 36a connected to a lower end portion of the seating portion 20. This seating portion 20 is supported by the guide pin 22 via a supporting member 22a.

[0030] The guide pin 22 is fitted to the frame body 26 via a guide bush 42. Moreover, a lower end portion of the guide pin 22 is connected to a piston rod 24a of the air cylinder 24. The guide pin 22 is configured capable of moving in an up-down direction integrally with the piston rod 24a while being guided by the guide bush 42.

[0031] The air cylinder 24 has its lower end portion fixed to a base portion 28 of the frame body 26, has its upper end portion (its end portion on the piston rod 24a side) upwardly disposed, and has its piston rod 24a configured capable of moving in an up-down direction of the drawing. This air cylinder 24 is connected with an air hose 44a and an air hose 44b, and operates by supply of compressed air from an external air supplying means (not illustrated).

[0032] The above-described air cylinder 24 and guide pin 22 configure a retraction mechanism of the seating portion 20, and the seating portion 20 is configured retractable in the up-down direction. Note that a retracting direction of the seating portion 20 is not limited to the up-down direction, and there may be movement in a horizontal direction or movement with three-dimensional displacement.

[0033] The vacuum generator 40 is fitted to the frame body 26. This vacuum generator 40 is supplied with compressed air via air hoses 36c, 36d and an electromagnetic valve 39. The vacuum generator 40 is configured by the likes of a vacuum ejector, for example, and can generate a negative pressure under action of compressed air supplied via the electromagnetic valve 39. The negative pressure generated by the vacuum generator 40 is supplied to an air manifold 38 via an air hose 36b.

[0034] The air manifold 38, as well as including passages that branch on its inside, comprises valves that control opening/closing of each of the passages. That air manifold 38 is connected with the air hose 36a. As shown in FIG. 1, in the workpiece holding jig 12, a plurality of the seating portions 20 are provided, and a plurality of the air hoses 36a connected to these plurality of seating portions 20 are connected to the air manifold 38 of FIG. 2. ON/OFF of suction of the individual seating portions 20 can be switched with opening/closing of the valves on the inside of the air manifold 38. In the case of there being several seating portions 20, a plurality of the air manifolds 38 and vacuum generators 40 may be provided. Note that a configuration may be adopted whereby ON/OFF of suction of the individual seating portions 20 is switched by the electromagnetic valves 39, instead of by the air manifold 38. In this case, the air manifold 38 need not be provided with the valves, and the air manifold 38 functions solely as a branching path of a passage joining the vacuum generator 40 and the seating portion 20.

[0035] Note that instead of the air manifold 38 being connected with the air hoses 36a from the plurality of seating portions 20, it is also possible for each of the seating portions 20 to be individually provided with the vacuum generator 40.

[0036] As shown in FIG. 1, a plurality of the seating portions 20 are disposed along a sewing direction of the sewing mechanism 14. The seating surfaces 20a of these seating portions 20 are provided along a sewing line where the sewing mechanism 14 performs sewing, and have substantially the same shape as a shape of the workpiece-to-be-sewn 58 lying along the sewing line (refer to FIG. 5).

[0037] The seating portions 20 are each respectively provided with the air cylinder 24 and the guide pin 22, and the individual seating portions 20 are configured to be retractable. That is, the seating portions 20 are configured to be retractable, in order, with approach of the sewing mechanism 14.

[0038] As shown in FIG. 1, the sewing mechanism 14 comprises a main body 50 formed in a U shape when viewed from the side, and projections 50a, 50b facing each other of that main body 50 are provided with a post bed 46, a pressing mechanism 48, and a sewing machine needle 49. As shown enlarged in FIG. 5, the pressing mechanism 48 and the sewing machine needle 49 are provided on a side of one of the projections, that is, the projection 50a, and extend out toward the other of the projections, that is, the projection 50b. The post bed 46 is provided on a side of the other projection 50b, and extends out toward the pressing mechanism 48 and the sewing machine needle 49.

[0039] The pressing mechanism 48 is configured projectable toward the post bed 46 via a shaft 48a, and is configured in such a manner that, when sewing is performed on the workpiece-to-be-sewn 58, the pressing mechanism 48 presses the workpiece-to-be-sewn 58 against a tip of the post bed 46. A tip of the pressing mechanism 48 is provided with a pair of through-holes 48b allowing insertion therethrough of a tip of the sewing machine needle 49.

[0040] The sewing machine needle 49 is fitted so as to be enabled to move in a reciprocating manner in the up-down direction by a drive mechanism (not unillustrated) of the projection 50a. Reciprocating movement of the sewing machine needle 49 describes an elliptical locus when viewed from a front of the main body 50. This results in it being configured such that even when the main body 50 is moved at a constant speed, the sewing machine needle 49 is penetrated through the workpiece-to-be-sewn 58 while maintaining a constant position with respect to the workpiece-to-be-sewn 58. The tip of this sewing machine needle 49 has a thread 52 inserted therethrough, and is inserted into a receiving portion of the post bed 46 via the through-hole 48b. Although the sewing machine needle 49 is not specifically limited, two items of the sewing machine needle 49 are illustrated, and these can form two parallel stitch patterns S.

[0041] The post bed 46 is provided with an unillustrated looper that holds a loop portion of the thread 52 formed by penetration of the sewing machine needle 49. That post bed 46 catches the loop portion of the sewing machine needle 49 on the next loop portion formed by a penetrating portion of the sewing machine needle 49 to connect up the loop portions, whereby sewing is performed.

[0042] The conveyor robot 16 proceeds to convey the sewing mechanism 14 and move a sewing portion of the sewing mechanism 14 along the sewing line at a constant speed. The conveyor robot 16 inclines the main body 50 in accordance with a shape of a sewing position of the workpiece-to-be-sewn 58, and thereby disposes the sewing machine needle 49 at an inclination perpendicular to the sewing position of the workpiece-to-be-sewn 58.

[0043] In the above configuration, the workpiece holding jig 12, the sewing mechanism 14, and the conveyor robot 16 operate under control action of an unillustrated control circuit. The sewing device 10 according to the present embodiment is basically configured as above. Operational advantages thereof, along with operation of the sewing device 10, will be described below.

[0044] As shown in FIG. 3A, the workpiece-to-be-sewn 58 is placed on top of the workpiece holding jig 12. The workpiece-to-be-sewn 58 is held by the workpiece holding jig 12 in a state of being seated on the seating surface 20a by being sucked through the suction holes 30 of the seating portion 20. In the case of the workpiece-to-be-sewn 58 used in an interior material of a vehicle, the strength thereof is comparatively high, hence even if a back surface of the workpiece-to-be-sewn 58 is partially seated on the seating portion 20, without the entire back surface being seated thereon, posture can be maintained to a certain extent. In this case, a portion where the seating portion 20 has been retracted can be elastically deformed to a certain degree with respect to pinching by the sewing mechanism 14.

[0045] Immediately after the workpiece-to-be-sewn 58 has been placed on the workpiece holding jig 12, sewing is started in a state of the workpiece-to-be-sewn 58 being sucked by all of the seating portions 20. Subsequently, an end portion of the workpiece-to-be-sewn 58 is pinched by the pressing mechanism 48 and the post bed 46 of the sewing mechanism 14, and sewing is performed while penetrating and withdrawing the sewing machine needle 49 through/from the workpiece-to-be-sewn 58.

[0046] As shown in FIG. 5, the post bed 46 is arranged separated in a vertical direction from the back surface of the workpiece-to-be-sewn 58 in order to prevent interference with the workpiece-to-be-sewn 58. In the case of the present embodiment, it may be separated by about 5 mm to 10 mm, for example. As a result, the shape of the workpiece-to-be-sewn 58 shaped by the seating portion 20 can be prevented from being deformed by the post bed 46, and positional misalignment of the sewing line can be prevented. The pressing mechanism 48 pushes the workpiece-to-be-sewn 58 to a position of a tip surface of the post bed 46, whereby the pressing mechanism 48 forms a flat surface on a surface of the workpiece-to-be-sewn 58 at a portion between the post bed 46 and the pressing mechanism 48, and adjusts an inclination of the flat surface to be substantially perpendicular to the sewing machine needle 49.

[0047] The sewing mechanism 14 moves at a constant speed in a rightward direction in the drawings, by means of the conveyor robot 16. Accordingly, as shown in FIG. 3B, the first seating portion 20 at a position interfering with the sewing mechanism 14 is retracted. When the seating portion 20 is retracted, supply of negative pressure to the seating portion 20 is stopped, thereby releasing suction of the workpiece-to-be-sewn 58. Then, by the air cylinder 24 being lowered, the seating portion 20 is retracted to a position not interfering with the sewing mechanism 14.

[0048] As a result, the workpiece-to-be-sewn 58 attains a state where both surfaces thereof have been set adrift from the seating portion 20, and in that portion, the sewing mechanism 14 can be moved along the sewing line. Note that even when the first seating portion 20 has been retracted, the shape of the workpiece-to-be-sewn 58 is maintained by the second seating portion 20, hence sewing can be performed in a state where the workpiece-to-be-sewn 58 has been shaped.

[0049] Depending on the inclination of the surface at the sewing position of the workpiece-to-be-sewn 58, the sewing mechanism 14 may be obliquely inclined. In that case, a plurality of the seating portions 20 in a range interfering with the sewing mechanism 14 should be retracted.

[0050] Next, as shown in FIG. 4, the second seating portion 20 is retracted in accordance with movement of the sewing mechanism 14. Moreover, the seating portion 20 that has been passed by the sewing mechanism 14 is returned to its original position.

[0051] As described above, the seating portion 20 that interferes with the sewing mechanism 14 is retracted in accordance with movement of that sewing mechanism 14, whereby it can be prevented that the seating portion 20 interferes with the sewing mechanism 14. As a result, sewing can be performed by the sewing mechanism 14 while maintaining a state of the workpiece-to-be-sewn 58 having been shaped by the seating portion 20.

Second Embodiment

[0052] In the present embodiment, an example where sewing of the stitch pattern S is implemented assuming an interior material configuring an instrument panel of a vehicle to be a workpiece-to-be-sewn 68, will be described. Note that a configuration of the sewing device 10 used in the present embodiment is basically similar to that shown in FIG. 1, and a description thereof will be omitted.

[0053] As shown in FIG. 6, the workpiece-to-be-sewn 68 is supplied in a state of having been shaped in a shape of the instrument panel. As shown in the enlarged portion of FIG. 7A, this workpiece-to-be-sewn 68 is configured from: a base material 68b constituted by a hard synthetic resin, that is formed in a required shape; and a skin material 68a that is soft, and is adhered to a surface of the base material 68b. The base material 68b is constituted by extrusion-molded polypropylene, for example, and the skin material 68a is constituted by a soft elastomer material that has been applied with a leather-like pattern, for example.

[0054] As shown in FIG. 6, a curve L of the workpiece-to-be-sewn 68 is a sewing line where sewing is performed, and the stitch pattern S is formed along this sewing line L. In the present embodiment, a plurality of the seating portions 20 are provided along the sewing line L. The seating surface 20a of the seating portion 20 is configured with substantially the same shape as the workpiece-to-be-sewn 68, and is provided with the suction holes 30 (refer to FIG. 1). Each of the seating portions 20 is provided with a retraction mechanism (not illustrated) that retracts the seating portion 20 in the Z direction of FIG. 6. A configuration of this retraction mechanism is similar to that described with reference to FIG. 2.

[0055] The sewing mechanism 14 (refer to FIG. 1) proceeds to move along the sewing line L of the workpiece-to-be-sewn 68. By the seating portions 20 of portions interfering with the sewing mechanism 14 proceeding to be retracted with movement of the sewing mechanism 14, sewing can be performed while shape distortion and positional misalignment of the workpiece-to-be-sewn 68 are prevented. Moreover, a configuration may be adopted whereby the workpiece-to-be-sewn 68 is supported making combined use of a fixed type workpiece holding jig 60 (a second workpiece holding jig) that does not include the retraction mechanism, for a portion separated from the sewing line L where there is no risk of there being interference with the sewing mechanism 14.

[0056] Moreover, the conveyor robot 16 (refer to FIG. 1) detects an inclination of a surface of a sewing portion of the workpiece-to-be-sewn 68, and controls an inclination of the sewing mechanism 14 so that the sewing machine needle 49 of the sewing mechanism 14 is perpendicular to the surface of the sewing portion. That is, as shown in the enlarged perspective view of FIG. 6, the sewing device 10 (refer to FIG. 1) detects two tangents B, C that are orthogonal at a portion between the two sewing machine needles 49, and finds a direction of a perpendicular line D to those tangents B, C. Then, the sewing device 10 controls the inclination of the sewing mechanism 14 so that an axial direction of the sewing machine needle 49 coincides with the perpendicular line D. Note that when the shape of the workpiece-to-be-sewn 68 is fixed, there is no need for the inclination of its surface to be detected by the conveyor robot 16 on each occasion of sewing. In this case, a configuration may be adopted whereby the conveyor robot 16 moves according to a teaching operation that is input in advance.

[0057] For example, in the cross section taken along the line VIIA-VIIA of FIG. 6, the inclination of the perpendicular line D at the sewing position is greatly inclined in a horizontal direction, as shown in FIG. 7A. In sewing of this portion, a plurality of the seating portions 20 that may interfere with the sewing mechanism 14 are retracted.

[0058] Note that for a portion curved at an acute angle as shown in FIG. 7B, the shape of the workpiece-to-be-sewn 68 cannot be maintained by the fixed type workpiece holding jig 60 alone. Therefore, in a conventional sewing device, tilting where the workpiece-to-be-sewn 68 inclines to left and right of the drawing ends up occurring when the pressing mechanism 48 is pressed against the post bed 46 of the sewing mechanism 14, and sewing cannot be accurately performed. In contrast, according to the present embodiment, the shape of the workpiece-to-be-sewn 68 can be maintained by the seating portions 20 on both sides, that is, a frontward side and a rearward side in the moving direction of the sewing mechanism 14, hence sewing can be accurately performed even on a portion curved at an acute angle.

Third Embodiment

[0059] In the present embodiment, an example where a cam mechanism 70 has been adopted for the retraction mechanism of the workpiece holding jig 12 (refer to FIGS. 1 and 2), will be described. As shown in FIG. 8A, in the present embodiment, the cam mechanism 70 is provided under the guide pin 22.

[0060] The cam mechanism 70 of the present embodiment comprises: a roller 72; and a sliding portion 76 that abuts on that roller 72. The roller 72 is supported by a shaft portion 72a to rotate in an arrow direction of the drawing by that shaft portion 72a. A recess 74 receding in an axial direction is formed in the roller 72. The sliding portion 76 is connected to a base end portion of the guide pin 22. This sliding portion 76 is configured to slide along an outer peripheral portion of the roller 72.

[0061] As shown in FIG. 8B, the sliding portion 76 moves downwardly with passage of the recess 74 of the sliding portion 76, and, accordingly, the guide pin 22 and the seating portion 20 connected to an upper end thereof descend. As a result, a retraction operation of the seating portion 20 can be performed.

[0062] Moreover, as shown in FIG. 8C, by the sliding portion 76 coming out of the recess 74 with rotation of the roller 72, the guide pin 22 rises, and the seating portion 20 returns to its original position. The workpiece holding jig 12 (refer to FIG. 1) can be realized by a plurality of such cam mechanisms 70 being disposed in the moving direction of the sewing mechanism 14. In this case, by staggering phases of the rollers 72 of the cam mechanisms 70, there can be realized a retraction mechanism that retracts the seating portions 20 in synchronization with movement of the sewing mechanism 14. Thus, according to the present embodiment, a device configuration of the workpiece holding jig including the retraction mechanism can be simplified.

[0063] In the above description, the present invention has been described by presenting preferred embodiments thereof. However, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications thereof are possible in a range not departing from the spirit of the present invention.