A sewing machine includes a support surface for two plies of material to be sewn together and a sewing mechanism that is attached to the support surface and is in operative connection with a machine controller, wherein a plate element positioned between the two material plies is arranged in the material feed area thereof. A vertical adjustment device for the plate element that is actuatable by the machine controller adjusts a vertical distance between the support surface and the plate element, and thus also influences the feed of material to the sewing mechanism. The vertical adjustment device is equipped with an electromagnet for adjusting the position of the plate element. The plate element is equipped with a magnet, which cooperates with the electromagnet.

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 includes a needle plate, a feed dog configured to move a workpiece, a vertical drive mechanism configured to vertically drive the feed dog, a switch mechanism, a cutting mechanism, and an actuator. The switch mechanism is configured to switch from an active state where the feed dog is driven, by the vertical drive mechanism, above and below an upper surface of the needle plate to an inactive state where an upper surface of the feed dog is maintained below the upper surface of the needle plate. The cutting mechanism includes a blade configured to cut a thread at a position below the needle plate. The actuator is configured to commonly drive the switch mechanism and the cutting mechanism.

A sewing machine includes a needle plate, a feed dog configured to move a workpiece, a vertical drive mechanism configured to vertically drive the feed dog, a switch mechanism, a cutting mechanism, and an actuator. The switch mechanism is configured to switch from an active state where the feed dog is driven, by the vertical drive mechanism, above and below an upper surface of the needle plate to an inactive state where an upper surface of the feed dog is maintained below the upper surface of the needle plate. The cutting mechanism includes a blade configured to cut a thread at a position below the needle plate. The actuator is configured to commonly drive the switch mechanism and the cutting mechanism.

A sewing machine includes a needle plate, a bed portion, a first urging member, a first engagement member, a second engagement member, and a lock release mechanism. The bed portion is configured to support the needle plate. The first urging member is provided inside the bed portion and configured to urge the needle plate upward. The first engagement member is provided on the needle plate. The second engagement member is provided inside the bed portion, and is configured to fix the needle plate in a fixed position by being engaged with the first engagement member of the needle plate pressed downward against an urging force of the first urging member. The lock release mechanism is configured to release the engagement of the first engagement member and the second engagement member.

A sewing machine includes a needle plate, a bed portion, a first urging member, a first engagement member, a second engagement member, and a lock release mechanism. The bed portion is configured to support the needle plate. The first urging member is provided inside the bed portion and configured to urge the needle plate upward. The first engagement member is provided on the needle plate. The second engagement member is provided inside the bed portion, and is configured to fix the needle plate in a fixed position by being engaged with the first engagement member of the needle plate pressed downward against an urging force of the first urging member. The lock release mechanism is configured to release the engagement of the first engagement member and the second engagement member.

A feeding device of an industrial sewing machine comprises a shell base, a main connecting rack having a first bar portion and a second bar portion, a terminal driven rack mounted at the first bar portion and the second bar portion, a first driven rack, a raising-driven mechanism and a driving shaft. The first driven rack is mounted at the first bar portion and connected to the shell base, and has a first sliding recess. The raising-driven mechanism has a second driven rack mounted at the second bar portion and having a second sliding recess. A raising-connecting rod is mounted at the second driven rack and the terminal driven rack. The driving shaft has a first crank mounted through the first sliding recess and a second crank mounted through the second sliding recess. The feeding device has a compact volume to facilitate ease in maintenance.

A feeding device of an industrial sewing machine comprises a shell base, a main connecting rack having a first bar portion and a second bar portion, a terminal driven rack mounted at the first bar portion and the second bar portion, a first driven rack, a raising-driven mechanism and a driving shaft. The first driven rack is mounted at the first bar portion and connected to the shell base, and has a first sliding recess. The raising-driven mechanism has a second driven rack mounted at the second bar portion and having a second sliding recess. A raising-connecting rod is mounted at the second driven rack and the terminal driven rack. The driving shaft has a first crank mounted through the first sliding recess and a second crank mounted through the second sliding recess. The feeding device has a compact volume to facilitate ease in maintenance.

A sewing machine includes a support surface for two plies of material to be sewn together and a sewing mechanism that is attached to the support surface and is in operative connection with a machine controller, wherein a plate element positioned between the two material plies is arranged in the material feed area thereof. A vertical adjustment device for the plate element that is actuatable by the machine controller adjusts a vertical distance between the support surface and the plate element, and thus also influences the feed of material to the sewing mechanism. The vertical adjustment device is equipped with an electromagnet for adjusting the position of the plate element. The plate element is equipped with a magnet, which cooperates with the electromagnet.

A sewing machine includes a support surface for two plies of material to be sewn together and a sewing mechanism that is attached to the support surface and is in operative connection with a machine controller, wherein a plate element positioned between the two material plies is arranged in the material feed area thereof. A vertical adjustment device for the plate element that is actuatable by the machine controller adjusts a vertical distance between the support surface and the plate element, and thus also influences the feed of material to the sewing mechanism. The vertical adjustment device is equipped with an electromagnet for adjusting the position of the plate element. The plate element is equipped with a magnet, which cooperates with the electromagnet.