Abstract: A differential feeding device for a sewing machine includes a spindle and a shaft. A cam is fixed on the spindle and two followers are engaged on the cam for allowing the cam to move the followers up and down. A lever is fixed on the shaft and has one end pivotally coupled to one of the followers and has the other end pivotally coupled to a lower end of another lever which has a groove and which has an upper end pivotally coupled to the other follower. A block is slidably received in the groove and moved along the groove for adjusting the relative movement between the followers.

Abstract: A device including an axle rotatably supported in a sewing machine, a shaft fixed in parallel to the axle, one or more cams fixed on the axle, a lever having one end pivotally fixed and having the other end slidably engaged with the cam, and a gripping device including a pair of members disposed on the shaft and a spring disposed between the lever and the members so that a thread can be gripped between the members, and the lever can be caused to move toward or to move away from the members so that a tension force applied to the thread can be adjusted.

Abstract: A presser of a sewing machine including a body movable downward for pressing an elastic band to be sewed, a roller rotatably disposed in one end of the body, a member having one end pivotally supported on a middle portion of the body and having a tapered surface formed in the bottom of the other end, a spring and a bolt engaged through the middle portion of the member for biasing the tapered surface downward against the roller, the elastic band being resiliently grasped between the tapered surface and the roller so that the elastic band can be stretched.

Abstract: An adjusting device for a lower knife being disposed in a support of a sewing machine and including a sleeve fitted in the support and having a pair of slots, a bolt rotatably received in the sleeve and having one end extended outward of the sleeve, a knob fixed to the bolt, a slide having an inner thread engaged with the bolt and having a pair of ribs slidably engaged with the slots of the sleeve so that the slide can be guided to slide longitudinally in the sleeve by rotation of the knob, the lower knife is fixed to the slide.

Abstract: A retaining device for coupling a cover to a sewing machine. A stop is fixed in the base. A lever has a middle portion pivotally supported on a support which is fixed on a bottom of the cover. A handle is formed on one end of the lever and is reachable from outside of the cover. A pawl is formed on the other end of the lever. A spring is provided to bias the pawl to engage with the stop so that the cover can be retained in a closed position. When the handle is pulled upward, the pawl can be separated from the stop so that the cover can be opened.

Abstract: A feeding apparatus includes a spindle and a shaft disposed in a base of a sewing machine. A lever is fixed on the shaft and can be caused to swing by the spindle. Two followers are engaged on the spindle. A pawl is fixed on each follower for feeding cloth. One follower is coupled to one end of the lever and the other follower is coupled to the other end of the lever by a link and a lever arm. The amplitude of swinging of the lever arm can be changed so that one of the pawls can be caused to move back and forth relative to the other pawl.

Abstract: A presser of a sewing machine including a body movable downward for pressing a cloth which includes one side edge, a rod laterally extended from the body, a bolt rotatably supported on the rod, and a guide including a back extended downward from one side of the guide for guiding the side edge of the cloth and a frame having a screw hole for threaded engagement with the bolt, so that the guide can be caused to move along a longitudinal direction of the rod and so that the back can be adjusted relative to the body by rotation of the bolt.

Abstract: A threading device for threading a lower looper of an overlock sewing machine, an orifice and a slot are formed in an arm of the lower looper, a hook if formed on a rear end of the arm and obliqued from the arm at a sharp angle, a holder is formed on one end of a lever, a thread threaded through the orifice of the arm can be carried by the holder toward the rear end of the arm, the thread will slip over the hook and located behind the hook when the holder moves beyond the hook, and the thread can be hooked by the hook and received in the slot of the arm when the lever is released.

Abstract: A feeding apparatus includes a spindle and a shaft disposed in a base of a sewing machine. A lever is fixed on the shaft and can be caused to swing by the spindle. Two followers are engaged on the spindle. A pawl is fixed on each follower for feeding cloth. One follower is coupled to one end of the lever and the other follower is coupled to the other end of the lever by a link and a lever arm. The amplitude of swinging of the lever arm can be changed so that one of the pawls can be caused to move back and forth relative to the other pawl.