Patent GB-430984-A (GB)
Title: Improvements in or relating to sewing machines
IPC: D05B15/00
Filed: 1933-11-28
Abstract: 430,984. Sewing-machines. BRITISH UNITED SHOE MACHINERY CO., Ltd., GOULDBURN, J., and KESTELL, T. A., Belgrave Road, Leicester. Nov. 28, 1933, No. 33257. Addition to 410,463. [Class 112] In a lockstitching-machine of the kind described in Specification 198,430, [Class 112], for sewing suit-cases, the machine is enabled to run at higher speeds by arranging that the needle and awl co-operate with the work support to impart a continuous feed and providing ample time in the movements of the needle to ensure that the loop of thread laid on the barb of the needle is properly engaged by the thread lifter and by the beak of the rotating shuttle. The machine illustrated has the two-speed driving device for stitching at different rates along the edges and corners as described in Specification 429,746. The needle and awl actuating mechanism and the thread-measuring device is as described in the parent Specification. The thread locking and stitch-setting device is as described in Specification 416,002. The construction and operation of the horn is as described in Specification 415,480. A curved hooked needle 21 and a curved awl 23 remain in a common plane and are operated by simple linkages. A needle guide 39 also moves along the line of feed with the needle and awl. A looper 41 and thread hook 43 co-operate to lay the needle thread in the hook of the needle and a thread lifter 45 engages one limb of the loop of needle thread to open the loop for the reception of the shuttle beak. The work support 49 has right angled faces with slots for the passage of the needle and awl. The work support is moved to-and-fro to assist the needle and awl to impart a smooth continuous feed. The horn has a pair of rotable frusto-conical rolls 55, 57. The work support 49 pivoted at its opposite ends to the upper ends of pins 85 freely rotatable on the ends of a pair of arms 87 with sleeves surrounding shafts 89. One of these sleeves has an arm 91 connected to a horizontal cam lever 93 which is oscillated in a horizontal plane by the cam 61 on the main shaft 15 to impart a to-and-fro feeding movement to the support 49. The connection between the arm 91 and the cam lever 93 is adjustable to vary the extent of the feed movement. The needle segment 113, the needle guide segment 115 and the awl segment 117 are all arranged to move in company along the line of feed by a reciprocating sleeve carrier connected to a cam mechanism including a collar 147, pins 159, arms 161, 165, pin 167 and parallel links 169, 171, link 175, lever 177 and cam 135. The needle reaches a position close to the shuttle at the end of the work-feeding movement imparted to the needle and awl. The needle and awl dwell in this position for a sufficient period of time to ensure that the loop pulled through the work is properly opened by the thread lifter 45 and engaged by the shuttle beak in spite of the high speed at which the machine works. The external work support 49 makes its idle return movement while the awl is extending into the work and commences to feed the work before the needle enters. The support 49 continues to assist the needle to feed the work as the needle and awl move to the left and continues to feed after the needle and awl have moved to their stationary position and retire from the work. Threads, cutting. To enable the threads to be severed close to the work for attaching a reinforcing metal corner piece, the work support 49 has a knife 359. To leave a long length of thread for tying by hand, or for weaving this into the stitches of a seam, the thread severing devices 365, 367 are provided.