GB1298106A - Improvements in sewing machines - Google Patents

Abstract

1298106 Sewing-machine UNION SPECIAL MACHINE CO 1 April 1970 [1 April 1969] 15328/70 Heading D1G Presser foot, feeding foot. A sewing-machine having a work supporting surface (10a, Fig. 1 not shown) along which multi-layered work pieces may be advanced, has work retaining and advancing means comprising a presser foot 48d engageable with the top surface of the work to urge the work against the surface, a four motion feed foot 50a engaging the top surface of the work near the presser foot, a drive shaft 36 above and parallel with the surface, the shaft having eccentric surfaces 36a, 51 on the shaft, the surface 36a causing lifting of the presser foot while the surface 51 lowers, substantially simultaneously, the feed foot on to the work and imparts a longitudinal movement to the foot to advance the work. The presser foot and feed foot are provided at the ends of bars 48, 50 respectively, the other ends of the bars engaging the eccentrics 36a 51, the former by way of a block 49 and jaws 48c on the bar 48. Bar 48 pivots on a pin 55 which carries a block 50d slidably accommodated at 50c in bar 50 to permit longitudinal movement of that bar. Pin 55 is carried in a block 41 engaging leaf spring 42 and slidably received in a housing 40 attached to the machine frame. A spring biassed presser bar end 45a engages the end of spring 42 and may be raised by a knee lever or pedal (not shown) linked to the presser bar (45) by mechanism 60-63, (Fig. 2). The shaft 36 is driven from a main bed shaft by a toothed belt and pulleys disposed either near the stitching position (Fig. 1 not shown) or adjacent the column of the machine. Eccentric 52 may be replaced by another of suitable throw to match the stitch length motion selected from the under feed dog. Feed dog. (Fig. 4 not shown). The feed dog (27) is connected to a feed bar (28) having one end connected (at 29) to a feed advance rocker (30) driven from an adjustable eccentric (33, Fig. 2 not shown). Feed lift is imparted to the bar by a pitman (34) embracing an eccentric (35) on the bed shaft (14). Looper. The machine, which forms a two thread chain stitch, employs a looper (22, Figs. 1 and 4 not shown) rockably mounted on a sleeve (23a) mounted on a shaft (23) to rock about the shaft for needle avoiding movement and to rock with respect to the sleeve to impart the loop seizing and shedding motions.