Patent GB-1254180-A (GB)
Title: Method and apparatus for stitching a succession of fabric workpieces
IPC: D05B73/12
Filed: 1969-02-27
Abstract: 1,254,180. Automatic sewing machine. UNION SPECIAL MACHINE CO. 27 Feb., 1969 [4 March, 1968], No. 10581/69. Heading D1G Sewing apparatus includes conveyors 34 for bringing workpieces to the stitching head of a sewing machine 70 which is mounted on a carriage 71 and moved in a direction parallel to the feed of the conveyors 34, the carriage 71 being first moved downstream in the direction of feed of the conveyors and then returned upstream in the opposite direction, manual control means, such as a treadle 249 operating pneumatic control means being provided to control changes in the direction of movement. The sewing apparatus comprises (Figs. 1 and 2) a frame 31 supporting the work conveyors 39, 41 and rails 81 supporting a carriage 71 on which is mounted the sewing machine 70. A motor 84 driving the sewing machine through a clutch operated by lever 86 is carried on the carriage, a similar motor 120 mounted on the frame drives the carriage along the rails through a belt 143 or a one way clutch as described later; the motor 84 also effects driving of the carriage.  Feed by chains, wheels &c. The work conveyors comprise endless belts 34 positioned below an upper belt 42 the lower run of the latter being pressed against the upper run of the former by spring rollers 56. Both upper and lower belts may be driven or the upper belt may be carried along by its frictional contact with the lower. A work guiding roller or a work loading conveyor (176, Figs. 21, 22 not shown) may proceed the upper belt. The shaft 48 carrying the belts 34 is driven through chain 116 from a shaft 113 driven by motor 84 as described later. Work placed in the nip of the belts is carried past the sewing machine to be stitched thereby. Driving. Motor 84 drives the sewing machine drive shaft 93 through a belt 91, the drive shaft pulley 93 driving, through belt 97 a shaft 95 connected through reduction gearing to a sprocket 101 (see Fig. 11) also mounted on the carriage and engaging a chain 105 which encircles a sprocket on shaft 113, providing the conveyor drive mentioned.  Feed by movement of stitch forming apparatus. The carriage is provided with belt grasping means (145, Figs. 14, 15, not shown) operated by fluid pressure to couple the carriage to the belt 113 driven by motor 120; alternatively that motor may drive shaft 113 through a one way clutch (166, Fig. 20, not shown). In either case the arrangement is such that when the carriage is driven along rails 81 the entraining of chain 105 by sprocket 101 increases the conveyor speed to keep the relative speed of the work and the sewing machine at a fixed value corresponding to the speed of the stitching instrumentalities and feed dog of the sewing machine. Work supports; uncurling edges; work guides; presser feet; indicating position of work. Work to be presented to the conveyor is laid on the loading platform 65 and aligned with an edge guide 35 or a line marked thereon and passes beneath an inclined rotary brush 188 driven from a separate motor and a presser device 186 (see Fig. 18). An edge guide 187 is adjustably mounted on the work plate 190. The brush device, the presser device and the sewing machine presser foot are movable vertically by fluid pressure devices controlled by a photo electric scanning device which detects the pressure or absence of a workpiece. Lowering of the sewing machine pressure foot permits sewing to commence. Operation. A control system employing air pressure is described (Fig. 16, not shown) but it is stated that relays and solid state circuiting may be employed.