UPPER FABRIC FEED DEVICE FOR SEWING MACHINE, UTILIZING PARALLEL MOTION MECHANISM FOR RECIPROCATING FEED FOOT AND PRESSER FOOT

摘要

An upper fabric feed device for a sewing machine, including a feet reciprocating mechanism for reciprocating feed and presser feet for feeding the work fabric on a throat plate. The reciprocating mechanism includes a first swing arm pivoted by a drive device, a pivotally supported parallel motion mechanism, a drive link mechanism which pivotally connects the first swing arm to the parallel motion mechanism, a pivotally supported second swing arm, a first connecting link pivotally connected to the parallel motion mechanism, a triangular lever connected to the first connecting link and second swing arm, and a second and a third connecting link connecting the triangular lever to the feed and presser feet, respectively. The parallel motion mechanism is supported pivotally about one of four apexes of the parallelogram defined by four motion links thereof. The feed and presser feet are both placed in fabric-contact positions when the distance between the two diagonally opposed apexes including the above-indicated one apex is the smallest.