Patent GB-637819-A (GB)
Title: Improvements in or relating to sewing machine
IPC: D05B3/20
Filed: 1947-08-08
Abstract: 637,819. Button-attaching machines. INTERNATIONAL BUTTON HOLE SEWING MACHINE CO. Aug. 8, 1947, No. 22016. Convention date, Feb. 3, 1944. [Class 112] Relates to a buttonattaching machine of the type described in Specification 476,039 in which, in making the normal fastening stitches, two opposed loopers 57, 58, Fig. 10, fixed-on one carrier 50, alternately engage a thread loop cast by the needle after passing through one button hole and carry it across to a position for entry by the needle when descending through the other button hole, each loop being engaged by the appropriate one of two spreaders 59, 60, Fig. 16, pivoted on the carrier 50 at 61, 62 and turned by the engagement of end pieces 63, 64 with a fixed plate 65. The stitch group is completed by a fastening stitch for which the needle descends twice through the same button hole, a, Fig. 10. The first thread loop is caught and spread in the normal fashion by the looper 59 and its spreader and then the movement of the carrier is quickened so as to make a complete oscillation, bringing the looper 58 into the position shown in Fig. 12, before the next descent of the needle. When the movement of the carrier is reversed the needle loop slips off the looper 57 and hangs free. It is then entered by the looper 58 and is brought back to and spread in the line of the needle's second descent through hole a. The free loop is held in position, for entry by the looper 58, by slots 107, 108, Figs. 16, 17, in plates 105, 106 into which the arms of the loop enter as the loop is spread. One wall of the slot 108 is extended downwards at 110 to increase the support against backward curling of the thread loop. The final needle thread loop is caught and spread by the looper 57 as the machine is stopped and the spread loop is cut by a cutter 100, Fig. 3a. The cutter 100 is pivoted at 75 on a part which can move axially with the shaft 52 and has a pin-and-slot connection 181 with a lever 182 pivoted on a stationary pivot 183. The lever 182 is connected by a link 185 and levers on a shaft 187 with a rod 163, which is slidingly mounted in the stop lever 164 and is moved downwards in the cushioning action of the stop arm. The machine may be used to attach a four-hole tab 120, Fig. 22. The stitches between the holes 128, 129 and between the holes 130, 131 are formed in the normal fashion. To make the stitch between the holes 128, 130, the carrier makes a complete oscillation between the two descents of the needle the loop thrown by the needle when in hole 128 is entered by the looper 57, left free in the notches 107, 108 and then brought back to the line of the hole 130 by the looper 58. The stitch between the holes 131, 129 is similarly formed. The looper carrier 50 is fast on a shaft 52, Fig. 3 which is mounted in a sleeve 53 and within a hollow actuating shaft 54. The sleeve 53 carries the plate 65 and is held from rotation but can slide axially in the machine frame. The shaft 52 and sleeve 53 are moved axially from the main cam when a four-hole button is being attached to co-operate with the needle and a dog clutch 85 maintains driving connection with the shaft 54. The carrier can be angularly adjusted by the screws 79, 80. The needle-vibrating mechanism is as described in Specification 579,253. Specifications 471,288, 476,080, 476,082, 541,058 and 546,300 also are referred to.