Patent GB-1352199-A (GB)
Title: Cyclic sewing machine
IPC: D05B19/00
Filed: 1971-07-06
Abstract: 1352199 Sewing machines BROTHER KOGYO KK 6 July 1971 [6 July 1970] 31615/ 71 Heading D1G In a cyclic sewing machine having a first cam disc 43 operatively connected by respective follower means to a clutch control device, a thread cutter and a thread tensioner, the follower means are rendered ineffective until actuated by a cam portion 19c of a feed cam disc 19, at the completion of a feed cycle by the cam disc 19, the feed cycle taking a number of stitches which is an integral multiple of the stitches corresponding to a rotation of the first cam disc. The cam disc 19 has two grooves 19a, 19b controlling feed transversely and longitudinally of the bed 12, In a first embodiment follower rollers 66, 74 and 103 (Fig. 6) engage the periphery of a disc 45 preventing roller 67, follower 76 and roller 104 from entering cam depressions of the respective cam discs of the assembly 43 until a roller 52a enters the cam disc portion 19c (Fig. 2) at the end of a feed cycle pivoting a shaft 51, arm 50 and hence the disc 45 so that the rollers 66, 74, 103 fall into depressions 45a, b and c and the cam followers can operate effectively. The roller 67 pivots arms 65 and 61 and a shaft 63 (Fig. 6) to raise catch 62 from a lever 53 which then rotates anticlockwise in Fig. 2 when a curved wire 68 (Fig. 3) displaces a drive belt from a driving pulley 57 to a free pulley 58 to disconnect the drive and an arm 56 engages a groove in the pulley 57 to stop it.  The follower 76 pivots a lever 73 to actuate the thread cutter mechanism 81 (Fig. 7) until stopped by a pedal operated stop 96. The roller 104 actuates a rod 109 (Fig. 9) and attached cam block 110 to release the thread tension until an arm 114 abuts an adjustable stop 115 on a lever 42. On depressing a pedal and pulling chain rod 100 downwards the stop 96 is lowered permitting the upper and lower threads to be cut by the blades 93b and 95 and the blade 91b, and groove 92 respectively and held by pawl 91a and holder 94. The rod also rotates the lever 42 lowering the stop 115 from the arm 114 and permitting complete release of the upper thread tension and rotation of part 18a to hold the thread. Further depression of the pedal. raising the needle causes an arm 39 (Fig. 3) to raise the work clamp against the force of a spring 37. A catch 72 on the lever 42 engages end 70 of lever 69 to prevent restarting of the machine until release of the pedal 7. In a first alternative construction (Figs. 11, 12 not shown) the second cam disc is arranged horizontally and has grooves engaged by levers coupled to followers engageable with the inner periphery of the vertically disposed first disc (127), the grooves having enlarged portions (135a, 136a, 137a) to permit operation of the clutch control device, thread cutter and thread tensioner.  In a further alternative, Fig. 14, the disc assembly 43 is movable axially on splines by linkage coupled to a peripheral groove 149 on the feed cam disc 19, the portion 149a of the groove causing the followers 67, 76 and 104 to be moved from the constant radius discs 45d, e, and f to the cam discs 46, 47 and 48.  As shown in Figs. 15A and 15B (not shown) the feed cam disc may have a plurality of evenly spaced cam portions 19c to render the first disc effective. To vary the stitch pattern the discs may be changed or gearing by which they are coupled to the main shaft may be changed.