Patent GB-191303342-A (GB)
Title: Improvements in or relating to Sewing Machines.
Inventor: WADE HAROLD
IPC: D05B69/22
Filed: 1913-02-08
Granted: 1914-04-08
Abstract: 3342. Wade, H., [United Shoe Machinery Co.]. Feb. 8. Boot - sole sewing - machines; stopping - gear, non-automatic; needles, hook, threading-devices for.-The needle-threading looper of a chainstitching machine is rendered inoperative by the abnormal movement of one part of the operating-mechanism relative to another part. The abnormal movement may be caused by part of the stop-gear when the machine is being stopped and thereby the threading of the needle during the last revolution of the machine may be prevented. In one construction, the movement of a rod 38, Fig. 6, forming part of the stop-gear described in Specifications 19,679/11 and 5453/12 is used to render inoperative the movement of the cam-actuated slide 60, 61, which normally imparts one of the movements to a needle-threading looper body 53 as described in Specification 17,328/08. The slide 60, 61 is telescopic; the front portion 60 being capable of sliding within the rear portion 61 but being compelled normally to move with the latter by a connexion between the two portions comprising links 62, 63 forming a toggle. Normally, the toggle is held straight by means of an eye-piece pivoted on the link 63 and sliding upon a rod 64 which is held parallel to the slide 60, 61. The rod 64 is carried by a shaft which is connected to the rod 38 of the stop-gear by means of a block 77 upon the rod 38, a lever 74 in pin-and-slot connexion with the block 77. a link 71 and a lever-arm 70. When the rod 38 moves to the right as the machine is being stopped, the rod 64 is turned to point downwards and thereby causes the subsequent movement of the link 63 to break the toggle and prevent the transmission of movement to the looper body 53. In another construction, the lever 120, Fig. 12. corresponding to the lever 57, Fig. 6, is not keyed to its shaft 58 but receives the oscillatory motion, which it communicates to the looper body, from a pin 122 on an additional keyed lever 121. The pin 122 fits into a hole in the lever 120 and when the lever 120 is moved axially away from the lever 121, into the position shown, it is disengaged therefrom and is rendered inoperative. Pins on a lever 123 engage an annular groove in the boss of the lever 120 to move it axially, and the lever 123 may be connected with a part of the stop-gear. The band brake 49<a>, Fig. 5, which brings the machine to rest, is tightened by means of a toggle 79, 80, Fig. 6; the outer end of the link 80 being slotted and supported on a lever 82 integral with the lever 74. A spring 85, Fig. 5, on the boss of the lever 49 normally keeps the toggle bent in opposition to a weaker spring 84, which is attached to the lever 82 and pulls upon a lug 83 formed on the link 80. When, in the stopping operation, the rod 38 is moved outwards, the lever 82 is moved with it and the spring 85 is enabled to straighten the toggle. Thereafter, the spring 85 is sufficient to maintain the toggle straight and on the return of the rod 38 under the pressure of its spring, the movement of the lever 82 is transmitted by the toggle to the lever 49 and the brake band is tightened. The end of the brake band embraces an eccentric 115 mounted in the end of the lever 49 and provided with a slotted lever which engages the starting-rod. In the starting operation, the eccentric 115 is rotated first of all, and during the first revolution of the main-shaft, a cam 119 breaks the toggle and completes the release of the brake. Governing needle thread.-The lever 49 is connected with known means for releasing the thread tension and the cam 119 is timed to break the toggle and thereby to re-establish the thread tension after the completion of the first loop-drawing stroke of the take-up so that the take-up draws thread freely from supply and does not pull the thread end from the thread-end holding-device. Welting and turnshoe guides. The welt-guide slide is withdrawn or stopped beyond the normal retracted position by means of a toggle connexion 112, 113 between the lever 97<a> and the lever 49. A cam-lever 110 is pivoted upon the arm 109 of the lever 97<a> and is coupled to the mid-pivot of the toggle by a link 114. In the normal position of the lever 49, the links 112, 114 are closer together than is shown, and the mid-position of the link 112 is in line with the pivot 111 so that the levers 109, 110 and the links 113, 114 move as one body. As the machine stops, the lever 49 assumes the position shown, and the link 112 so acts on the links 114, 113 that they increase the movement received from the lever 110 as they transmit it to the lever 109, and the welt-guide slide consequently receives an increased retraction.