A presser foot position retainer includes a presser foot and a restricting member. The presser foot is swingably attachable to a presser holder of a sewing machine. The presser foot includes a shaft extending in an axial direction, a restricted portion, and a pressing surface configured to press a workpiece. The restricting member includes a restricting portion capable of contacting the restricted portion. The restricting member is attachable to the presser holder. The restricting member is configured to move between a first position and a second position by a user operation. When the restricting member is located at the second position, the restricting portion is in contact with the restricted portion to limit a swingable range within which the presser foot attached to the presser holder is swingable about the shaft to less than that when the restricting member is located at the first position.

A presser foot position retainer includes a presser foot and a restricting member. The presser foot is swingably attachable to a presser holder of a sewing machine. The presser foot includes a shaft extending in an axial direction, a restricted portion, and a pressing surface configured to press a workpiece. The restricting member includes a restricting portion capable of contacting the restricted portion. The restricting member is attachable to the presser holder. The restricting member is configured to move between a first position and a second position by a user operation. When the restricting member is located at the second position, the restricting portion is in contact with the restricted portion to limit a swingable range within which the presser foot attached to the presser holder is swingable about the shaft to less than that when the restricting member is located at the first position.

A pressing device includes a first member including an attaching portion attachable to a presser bar and being configured to move in an up-down direction together with the presser bar urged downward; a second member including a contact portion contactable to a pressing portion including at least a portion of the first member or at least a portion of the presser bar and being configured to support a presser foot capable of downwardly pressing a workpiece on a bed, and in a state where the first member is attached to the presser bar and the second member supports the presser foot, move between a first position where the contact portion is in contact with the pressing portion and a second position where the contact portion is spaced from the pressing portion; and a first guide portion configured to guide movement of the second member relative to the first member.

A pressing device includes a first member including an attaching portion attachable to a presser bar and being configured to move in an up-down direction together with the presser bar urged downward; a second member including a contact portion contactable to a pressing portion including at least a portion of the first member or at least a portion of the presser bar and being configured to support a presser foot capable of downwardly pressing a workpiece on a bed, and in a state where the first member is attached to the presser bar and the second member supports the presser foot, move between a first position where the contact portion is in contact with the pressing portion and a second position where the contact portion is spaced from the pressing portion; and a first guide portion configured to guide movement of the second member relative to the first member.

A sewing machine includes: a needle vertical movement mechanism which moves a sewing needle; a moving mechanism which holds a workpiece by a holding frame; an inner presser-foot device which moves an inner presser foot on an upper side of the workpiece held by the holding frame; a control device which controls the moving mechanism based on sewing data in which stitch positions are defined in order in a series of sewing; and a height detector which detects a height of the inner presser foot. The control device lowers the inner presser foot to an upper surface of the workpiece held by the holding frame, detects the height of the inner presser foot by the height detector, and determines suitability of a thickness of the workpiece, at one or plural stitch positions defined in the sewing data before starting the sewing in accordance with the sewing data.

A sewing machine includes: a needle vertical movement mechanism which moves a sewing needle; a moving mechanism which holds a workpiece by a holding frame; an inner presser-foot device which moves an inner presser foot on an upper side of the workpiece held by the holding frame; a control device which controls the moving mechanism based on sewing data in which stitch positions are defined in order in a series of sewing; and a height detector which detects a height of the inner presser foot. The control device lowers the inner presser foot to an upper surface of the workpiece held by the holding frame, detects the height of the inner presser foot by the height detector, and determines suitability of a thickness of the workpiece, at one or plural stitch positions defined in the sewing data before starting the sewing in accordance with the sewing data.

A pressure adjustment mechanism of the sewing machine presser foot comprises a motor, a screw actuated by the motor, a spiral spring and a pressing plate for pressing against an upper end of the presser foot. A nut is screwed and connected on the screw, and the nut is lifted or lowered by the screw. The pressing plate is underneath the nut. The circumferential direction of the nut is unfixed. The spiral spring is located between the nut and the pressing plate, an upper end of the spiral spring is pressed against the nut, and a lower end of the spiral spring is pressed against the pressing plate. The spiral spring is being compressed under the effects of the nut and the pressing plate.

A pressure adjustment mechanism of the sewing machine presser foot comprises a motor, a screw actuated by the motor, a spiral spring and a pressing plate for pressing against an upper end of the presser foot. A nut is screwed and connected on the screw, and the nut is lifted or lowered by the screw. The pressing plate is underneath the nut. The circumferential direction of the nut is unfixed. The spiral spring is located between the nut and the pressing plate, an upper end of the spiral spring is pressed against the nut, and a lower end of the spiral spring is pressed against the pressing plate. The spiral spring is being compressed under the effects of the nut and the pressing plate.

A sewing machine comprises a crank shaft, a first drive shaft, a second drive shaft, a needle assembly, a presser foot, and an upper walking foot. A first crank arm assembly is connected to the crank shaft to the first drive shaft. A first linkage assembly is connected to the first drive shaft to the needle assembly. A second crank arm assembly is connected to the first drive shaft to the second drive shaft. A second linkage assembly is connected to the second drive shaft to the presser foot and the upper walking foot. The second linkage assembly is configured to cause out-of-phase reciprocatory movement of the presser foot and the upper walking foot. The second crank arm assembly has a variable length that is selectably adjustable by an operator to yield at least first and second different stepping heights of the upper walking foot.

A sewing machine comprises a crank shaft, a first drive shaft, a second drive shaft, a needle assembly, a presser foot, and an upper walking foot. A first crank arm assembly is connected to the crank shaft to the first drive shaft. A first linkage assembly is connected to the first drive shaft to the needle assembly. A second crank arm assembly is connected to the first drive shaft to the second drive shaft. A second linkage assembly is connected to the second drive shaft to the presser foot and the upper walking foot. The second linkage assembly is configured to cause out-of-phase reciprocatory movement of the presser foot and the upper walking foot. The second crank arm assembly has a variable length that is selectably adjustable by an operator to yield at least first and second different stepping heights of the upper walking foot.