Patent GB-133053-A (GB)
IPC: D05B3/08
Abstract: 133,053. United Shoe Machinery Corporation, (Assignees of Leveque, B. T.). Sept. 26, 1918, [Convention date]. Button-hole sewing-machines.-An eye-ended buttonhole is sewn with a usual form of overedge stitch by means of an upper eye-pointed needle, a lower straight eye-pointed needle which passes obliquely through the work, and an under work looper. These parts are mounted in revoluble heads of a known type, and at the completion of stitching are stopped in their retracted positions by being disconnected from their driving mechanisms. The buttonhole is cut progressively by a knife reciprocating in advance of the needles and parallel with the lower needle. It cuts up one edge, round the eyed end and down the other edge of the button-hole and, during the stitching of the bar end, is removed to an inoperative position without being stopped. The work clamp is divided and used to stretch the material along the length of the button-hole and not transversely. Special grippers are provided, which, after a buttonhole is finished, move the work into position for the next buttonhole. The work plate is cylindrical and is moved axially for spacing the side stitches, and is turned about its axis for the necessary lateral adjustment. The main controlling cam is driven by a worm which is clutched to the single main shaft for rapid movement during the turning of the stitching heads, and is clutched intermittingly to a reciprocating member for the stepby-step movement during stitching. Stitch-forming mechanism.-The upper needle 2, Fig. 4, is carried by a bar 10 which reciprocates within a revoluble sleeve 16 and is actuated by a crank 188, Fig. 30, a connecting-rod 190, Fig. 4, a toggle 192, levers 186 and 178, and a link 184. The lower needle bar 50, Fig. 20, and the threadless looper 6 are carried in a turret 18 and are actuated from a central reciprocating rod 60, which is connected to the lever bar 50 by levers pivoted at 54 and a link 56, and imparts loopengaging and needle-avoiding movements to the looper by means of a linkage 80 with a crank 82 on a cross-shaft 74, a crank 72 and a link 70 between it and the looper carrier 64, and a cam 76 engaging an arm 78 on a rocking sleeve 68 upon which the looper carrier 64 is pivoted. The rod 60 has a ball-and-socket connexion with a lever 62, which is actuated from a crank 140, Fig. 30, by a connecting-rod 142 and a lever 144. The revoluble sleeve 16 and the turret 18 are turned by gears 16, 26 and shafts 14, 24 which are partially rotated by means of toothed quadrants actuated from the main cam At the completion of the stitching, the levers 62, 178, when at their extreme retracted positions, are disconnected from the driving levers 144, 186 by similar devices shown in Figs. 4 and 27. The levers 62, 178 are normally held against stops on the levers 144, 186, so as to move with them, by powerful springs 148, 196 and are also locked to them by spring-held latches 152, 198. Stop levers 156, 200 are urged towards the plane of the levers 62, 178 by springs, but are normally held back by levers 168, 282, When these levers are moved at the close of stitching by cam-actuated rods 174, 204, the stop levers press against the side of the levers 62, 178 and snap past them, to restrain them from further movement, as they reach their extreme positions. In the movement into contact with the side of the levers 62, 178 the levers 156, 200, &c. carry projecting inclines 160, 199 into the path of the latch levers 152, 198 so that, as the levers 62, 178 reach their extreme positions, the latch-hold is removed and thereafter the levers 144, 186 are free to oscillate without effecting movement of the stitching parts. A projection on the stop-lever 200 is used, through the lever 207, to release the thread tension. Buttonholes, cutting.-The cutting-knife 86, Fig. 8, is carried by a bar 90 which is reciprocated from the needle-bar 10 by the linkage 98, 94, 96. Its direction of reciprocation is parallel to that of the lower needle. The lever 94 is pivoted upon a bracket 92 supported upon a sleeve 104 which can slide vertically in the machine head. When raised to the position shown in Fig. 8, the knife reciprocates ineffectually above the work. This movement of the bracket 92 is imparted to it by a lever 126, Fig. 4, actuated by a cam 132 on the shaft 14. The bracket 92 is rotated, during the formation of the eyed end, independently of the stitch-forming devices by gear 116, a shaft 114, and a toothed cam-actuated quadrant. The connexion between the gear wheel 116 and the sleeve 104 supporting the bracket 92 is a long toothed dog clutch 112, which permits the vertical movement of the sleeve and bracket, without disengagement from the gear wheel. Work clamps.-The lower clamp member or work-plate 206, Figs. 4 and 27, is supported by radial arms 208, 210 upon the cam-shaft 48 and a pin 212. The work-plate is curved and concentric with the shaft 48, and its edges enter between guide-plates 216. The upper clamping member is pivoted between pillars 244 on the work plate It is provided with front and rear foot members 234, 236, Fig. 37, pivoted upon branched arms 238, 246. The arm 238 is integral with the main tubular part 240 and the shank 248 of the arm 246 slides within, being pressed forwardly by a spring 250. When the work-damp is closed the arm 246 is drawn rearwardly by means of a. camedged collar 256, Fig. 4, forming the boss of a lever 258 which is raised by a cam 272. A threadcutting and end-holding implement 324 is pivoted on the forward foot 234, and is linked to a lever 328 on the back of the extension of the upper clamping member. The clamp is closed by a spring 260 and is opened by a cam lever 262 which also engages the lever 328, and through it causes the cutting of the thread when the clamp is opened. The clamp as a whole is moved step by step by direct connexion of an arm 226 with the cam 220, and is moved about the shaft 48 for the lateral displacement of the work by means of a cam-actuated lever 224 having a part 230 in sliding engagement with a pin 228 on the lower clamp member. Buttonhole-spacing mechanism.-A pair of grippers 274, 276, Figs. 4 and 2", are mounted on a lever 280. The stalk 282 of the upper gripper slides in the body of the lower one and is urged towards it by a spring 284. During the buttonhole-forming operation, the grippers are held open by a cam 286 and lever 288. When a buttonhole is completed, the grippers are permitted to close on to the work and a cam lever 302, Fig. 27, moves to the left. A rod 310 pivoted on the lever passes through a block 306 on the gripper carrying lever 280 and between the head of the rod and that block there is a spring 308 which, when the lever 302 moves to the left, carries the lever 280 with it until the latter is checked by a stop 314. The position of the stop 314, which determines the movement of the lever 280 and thereby the spacing of successive buttonholes, can be adjusted by turning a shaft 316 upon a screwed portion of which the stop is threaded. Driving.-All the machine parts are driven from one cord pulley 346, Fig. 30, mounted on a sleeve 344 which can be moved longitudinally by a lever 388. During stitching. the lever 388 is forced towards the left hand and the pulley 346 is clutched to the main shaft 138. In order to return the stitching devices to their initial positions rapidly, the lever 388 is moved to the right hand, the clutch 346, 350 is opened and a clutch surface at the other end of the sleeve 344 engages and drives a second sleeve carrying the worm 336 by which the cam-shaft 48 is driven. The step-by-step movement of the cam-shaft during stitching is obtained by means of an annular clutch member 354 which is oscillated from the main drive by a cam 368 and linkage 364, 356 and 358. This clutch member is moved to the right, to clutch and drive the sleeve carrying the worm 336 throughout each forward oscillation by means of an eccentric 374 and linkage 378, 382. The lever 388 has a toe 392 in engagement with a toe 394 on the lever 382 and when the lever 388 is moved to the right, the lever 382 is moved to the left against the pressure of a spring 384 which normally holds it in operative engagement with a shoulder on the connecting-rod 378. The clutch levers are connected by a rod 398 to a cam-lever 396 and a spring 402 holds the lever up against a stop-collar on the rod. The machine is stopped when the cam groove 404 brings the clutch levers to the neutral position and at that time a bowl on a lever 412 which is normally held by a concentric groove 414 is opposite to an enlarged part 416 of the groove. To start the machine, a lever 406 is depressed by a treadle and carries with it the cam lever 412 which the clearance at 416 permits to move. The forward portion of the lever 412 forces the rod 398 downwards against the spring 402 and clutches the pulley 346 to the sleeve of the worm 336. The treadle lever is held depressed until the neutral position part of the cam-groove 404 moves from the lever 396 and thereafter the machine is controlled by the cam.