Patent GB-596489-A (GB)
Title: Improvements in or relating to sewing machines
IPC: D05B47/00
Filed: 1945-07-27
Abstract: 596,489. Sewing-machines. WILLCOX & GIBBS SEWING MACHINE CO., Ltd. (Willcox & Gibbs Sewing Machine Co.). July 27, 1945, No. 19257. [Class 112] Governing needle-thread; frames.-A rotary take-up, which may comprise an 'adjustable thread-engaging element, is provided with a guard which has yielding engagement with means to confine the thread within the guard while allowing easy threading of the take-up. The guard may be transparent, and may be hinged to allow easy access to the take-up. In the arrangement shown in Fig. 2, the take-up comprises a disc 24 rotating in a recess in the face of the machine head 11 and carrying a thread-engaging pin 26, which may be attached to the disc by an eccentric shank to permit of adjustment of its position; balancing holes 49 are cut in the disc. The guard 38, which is resilient and is preferably of transparent elastic material, is fixed to the head 11 by screws 41 passing through a spacing-plate 42 so that a narrow thread-space is left between the guard and the head; the guard is formed with an annular channel in which the take-up pin 26 moves, and its upper end yieldingly engages behind a bent finger 43 projecting from the machine head to prevent the thread from being thrown out while allowing it to be snapped past in inserting it. A flange 97 projecting from the head confines the thread at the side. In a modification the guard is fixed to, or formed integral with, a member mounted on a hinge pin at the bottom of the head, so that it can be swung down to allow access to the take-up. Before reaching the rotary take-up the thread passes over a tension device T and a resilient auxiliary take-up 53. The letter is formed by the projecting end of a spring 27, Fig. 4, surrounding the hub 67 of one of the tension discs 61, the inner end 51 of the spring being engaged in one of a number of holes in a cover 74 secured on the hub 67 by a set-screw. The part 53 of the spring passes through a slot 73 in the cover 74, normally bearing against one end of the slot; adjustment of the normal position of this take-up is effected by shifting the cover 74 on the hub 67, and adjustment of the stress in the spring 27 by inserting its end 51 in a different hole in the' cover. Thread-tensioning devices. - The tension device T comprises a wheel 62, over which the thread passes, mounted between two flanged discs 60, 61 on a spindle 56 carried in lugs on the machine head, the disc 61 being prevented from rotation on the spindle by a cross-pin 65 engaging a slot in the spindle, and the members being pressed together by a spring 81 with adjusting nut 86. In the form shown, washers 63, 64, preferably of felt, exert friction on the wheel 62 under the pressure of the disc 61, but the thread may also be gripped between the flanges of the discs 60, 61, and these may be the only devices retarding the motion of the thread. Presser-bars, lifting ; controlling threads otherwise than in stitch-forming.-A handlever 15, Fig. 2, pivoted on the spindle of the thread-tension device T, has a cam portion engaging the underside of a forked member 17 projecting from the presser-bar 14 to lift the latter to release the work, and a treadle-operated lever 18 has an arm engaging the fork for the same purpose. A third arm of the lever 18 engages a pin 89, Fig. 4, sliding in an axial bore in the spindle 56 of the tension device to engage the cross-pin 65 and release the tension when the presser-bar is lifted.