UNIT OF HOLD-DOWN LUG OF SEWING MACHINE MECHANISM FOR MATERIAL FEED Russian patent published in 1998 - IPC

FIELD: machine equipment of light industry and services. SUBSTANCE: unit has rod 3 with coupling 7 and hold-down lug 1 and cam 9 for lifting and lowering of lug 1 secured with rotary axle to body. Rod 3 is spring-loaded by upper spring 4 and has lower spring consisting of two parts 13 and 145 engageable with rod in the course of sewing. They are perpendicular to the first spring and rest on coupling 7 and bracket 15 with through hole to pass rod and is movable relative to machine body guides. One end of lower spring is connected with rod coupling and its other end with bracket. With lug 1 lifted from cam 9, only upper spring 4 operates, and with lug 1 lifted from rack 12, all springs 4, 13 and 14 operate. At this moment, bracket 15 is locked by cam 9 through cantilever 18 with pin and shaped recess 19 on cam 9. In this case, shape of shaped recess is similar to cam working surface kinematically locked with bracket through cantilever 18 with pin. Axis of cam rotation lies in the plane square to parallel planes of location of longitudinal axes of rod of hold-down lug 1 and cantilever 18 of bracket 15 and crosses these axes. Tangent to profile of cam working surface on the line of rod of hold-down lug, at the moment of bracket locking, coincides with plane of touching of bracket by cam and square to rod. EFFECT: simplified design and higher reliability. 3 cl, 2 dwg