Patent GB-223801-A (GB)
Title: Buttonhole sewing machine
IPC: D05B3/06
Filed: 1924-02-27
Abstract: 223,801. Fairweather, W., (Singer Manufacturing Co.). Feb. 27, 1924. Button-hote sewing-machines; starting and stopping gear. - A machine of the general type described in Specification 15049/15 is provided with thread-cutting mechanism by which the upper thread is cut in the stitching position and the work-holder is then moved rearwardly to a position in which the lower thread-cutting mechanism comes into action to sever the drawn out length of looper thread. In the machine described the needle-bar operating shaft 9 and looper-operating shaft 15 are geared to a main shaft 13 to be driven at double its speed. The needle-bar and a turret 14 are turned by usual connections with a feed-wheel 17. The work-plate and holder are of usual construction, the longitudinal movement of the work-clamp being derived from the feed-wheel 17 and the lateral movement from a wheel 38 on the rapid-feed shaft 39 geared to the wheel 17. The shaft 39 and wheel 17 are driven at slow speed during sewing by the vertical shaft 11, driving the needle-bar shaft, and during rapid feed are automatically geared to a shaft 42. The connection and disconnection of the shafts 39, 42 are effected bv continuously-reciprocating levers which are held in inoperative positions by latches, the throw-out latch being operated by cams on the wheel 38 and the throw-in latch by a cam on the cuttershaft 56 and by the stop-motion mechanism, which controls the connection of the sewing-shaft 13 with the continuously moving pulley 59. The cutting mechanism is operated in known manner by means including a device for coupling the shaft 56 to a continuously-running pulley which also operates the clamp mechanism. The period of stitch-forming is controlled by usual means operated by the controlling wheel 38. After the button-hole has been cut a cam 100, Fig. 1, on the button-hole cutter shaft engages a T-shaped lever 101 and moves it to operate the clampspreading device. Just before the machine comes to rest a tooth 102, Fig. 2, on the control wheel 38 engages the end of a lever 104 connected by a linkage 106, 107 to a push-rod 108 carrying an arm 109. The push-rod engages the arm 30 of the work-clamp to open it and at the same time the arm 109 engages the clamp-spreading toggle to unspread it. Thread-cutters and thread-end holders. - The upper-thread cutter and nipper is of the type described in Specification 142,561 and comprises a spring-stressed rod which is released by a latch 83. The latch is tripped at the end of a sewing cycle, and before the work holder is shifted from sewing position, by means of a vertical bar 89 connected to the upper-thread tension-release lever which in turn is operated in usual manner from the stop-motion device. The rapid feed is at the same time tripped into action and withdraws the work-clamp, drawing out suitable lengths of under-thread and cord for the next button-hole. A scissors device 126, 127 is then projected below the work and closed by the action of a cam-slot 133. This device is similar to that described in Specification 223,124 but is simpler and actuated independently of the button-hole cutter. The cutter-lever 129 is connected by a link to a lever 135 actuated by a cam groove 139 on the rapid-feed shaft 39. Specifications 126,119, 179,278, 183,873, 184,134, 184,135, 197,463, 197,629, and 198,628 are referred to.