Abstract: A single-operation cam mechanism includes a cam body with a cam surface extending along the body from an entrance location to an exit location. A cam follower is retained in a waiting position adjacent a part of the cam body at which the exit location is found. When the cam follower is moved free of the retainer, a spring forces the cam follower to the part of the cam where the entrance location is found. Then, as the cam rotates, the cam surface engages the follower and forces it back through the exit location and past a resilient trap to the waiting position. The trap snaps shut after the follower has been forced past it, and the surface of the trap then prevents the follower from moving back into engagement with the cam surface except by way of the entrance location. In an underbed thread trimmer, a support member for the cam follower engages a pin connected to blade-like members, some of which have hooks, to carry one set of such members to a position in which their hooks engage looptaker thread.

Abstract: A single-operation cam mechanism includes a cam body with a cam surface extending along the body from an entrance location to an exit location. A cam follower is retained in a waiting position adjacent a part of the cam body at which the exit location is found. When the cam follower is moved free of the retainer, a spring forces the cam follower to the part of the cam where the entrance location is found. Then, as the cam rotates, the cam surface engages the follower and forces it back through the exit location and past a resilient trap to the waiting position. The trap snaps shut after the follower has been forced past it, and the surface of the trap then prevents the follower from moving back into engagement with the cam surface except by way of the entrance location.

Abstract: A picking arm for an underbed thread trimmer which engages the bobbin thread and one limb of the needle thread and holds them so that a thread catching arm may engage the bobbin and needle threads and draw them into severing relation with a cutting edge of a thread cutting blade. After the threads have been cut, the picking arm returns to a rest position with the end of the bobbin thread retained in a channel contained in its thread engaging extremity. The bobbin thread is held in a position where it will be available for concatenation with a needle thread for the production of lockstitches.

Abstract: The upper one of two spherical bearings supporting the needle bar of a sewing machine for endwise reciprocation is carried in a gate that is pivotally mounted between bifurcated portions of a fixed support located on the rear side of the machine casing. A link is pivotally mounted between bifurcated portions of the gate and operably connected to driving means effective to impart reciprocating movements to the gate resulting in zig-zag motion of a needle attached to the lower end of the needle bar.

Abstract: A work feeding mechanism for sewing machines including a feed dog with two pair of mutually orthogonal serrated teeth to drive a fabric past a stitch forming area in directions defined by mutually orthogonal axes. The feed dog is pivotally fastened to one extremity of a feed bar whose opposite extremity is suspended by gimbals from a slidable member carried in the bed. Means are disclosed to selectively impart oscillations of a varying amplitude and direction to the slidable member in timed synchronization to the motion imparted to the feed dog, to drive the feed dog in lateral and longitudinal directions of fabric feeding motion which extend along the length of the sewing machine bed and normal to the length of the bed. Fabric feeding information for the work feeding mechanism may be stored in an electronic memory to permit the production of ornamental stitch patterns.

Abstract: A mechanism for selecting the tension setting of a needle thread tension device for sewing machines. A slot is formed in the face of the sewing machine arm top cover through which extends an operator influenced tension selecting knob. The tension device for influencing the needle thread tension is connected to the tension selecting knob by a leaf spring and lever fulcrummed to the arm top cover. Movement of the tension selecting knob along the slot in the arm top cover varies the force exerted on the needle thread by the tension discs contained within the tension device.

Abstract: A sewing machine work feeding mechanism of the drop feed variety having a feed dog adjustably supported at one end of an elongated feed bar. The pivot end of the feed bar is supported between a pair of pintles by a trunnion pin. The trunnion pin is journalled in a threaded pivot pin which is supported within the feed bar by a threaded sleeve which is free to rotate within the pivoted end of the feed bar. The inclination of the feed dog with respect to the throat plate may be adjusted by turning the threaded sleeve against the threaded pivot pin, thereby changing the height of the feed bar with respect to the plane of the support pintles. The feed dog is attached to the feed bar by a feed dog carrier and a threaded stud which permits the height of the feed dog carrier to be adjusted relative to the feed bar, thereby allowing independent adjustment of the height of the feed dog above the throat plate.