Patent GB-915349-A (GB)
Title: Compound stitching devices
IPC: D05B1/20
Filed: 1961-07-12
Abstract: 915,349. Sewing-machines. MAN-SEW CORPORATION. July 12, 1961 [July 18, 1960], No. 25208/61. Class 112. A sewing-machine has three independent stitching stations producing three separate lines of stitching in superimposed upper and lower fabric plies, one station stitching the plies together and each of the others producing overedge stitching which overcasts each ply edge separately, members being provided for separating the ply edges and directing one ply edge out of the path of one of the overcasting stations as the edge of the other ply is being overcast at that station, and for directing the overcast ply edge out of the path of the other overcasting station as the other ply edge is overcast at the latter station, the overcasting of the ply edge and the joining stitching being performed during one passage of the plies through the machine. Seams.-Two embodiments of the machine are described, that of Fig. 1 produces a seam in which the overcast edges lie together while in that of Fig. 11 the overcast upper ply is bent back on itself before being stitched to the lower ply to form an opened seam which requires no subsequent ironing. The joining seam may be formed of lock stitches or by one- or twothread chain stitches, and the overedge stitching may be formed of two threads, as shown, or three. Overedge stitching, multiple needle machines, trimming work, throat plates, presser feet.-The machine is a modification of the lock-stitch machine described in Specification 802,833 and includes a work-trimming blade 96 which cooperates with a fixed blade secured to the throat plate. Three needles are provided in a single holder 216, a forward overedge sewing needle 100 (see Fig. 3), co-operating with loopers 251, 260 and a stitch finger 311, a plyjoining needle 12 and a rear overedge sewing needle 200 co-operating with loopers 253, 262 and a stitch finger 304 formed on the throat plate 298. The finger 311 extends rearwardly from adjacent a needle hole 308 in a ply separator 306 mounted on the throat plate and is spirally twisted so that the upper ply passing above the separator 306 and receiving an overedge stitch formed around the finger by the needle 100 &c. follows the twist of the finger (see Fig. 5) and is deflected around the contour of a wall 219 provided on the presser foot 214 which maintains the upper ply edge in a vertical position out of the path of needle 200. Meanwhile the lower ply passing beneath the separator 306 is deflected out of the path of the needle 100 by passing into a guide channel formed between a projection 310 on the undersurface of the separator and the edge 300 (see Fig. 8) of a relief formed along the edge of the throat plate, a guard 315 curling the edge of the ply out of the path of loop 251. After passing through the passage the ply returns to its horizontal position and receives its overedge stitch at the position of the needle 200. The plies have been, meanwhile, stitched together by the needle 12. In the second embodiment, Fig. 11, the overedge stitching stations are positioned in advance of the ply-joining stitching station, and the spiral finger 311 is replaced by a wire finger 327 (see Fig. 14) on a presser foot 314. In this embodiment the plies are separated by a sharp edge 402 formed on the throat plate in advance of the hole for the needle 100 and the lower ply is deflected through passage 399 and bent away from the needle by the contour of projection 401. A spring- biased adjustable depressor 328 on the presser foot coaots with the edge 402 to separate the plies. The upper ply receives its overedge stitching formed around the finger 327 by the needle 100 as before. The wire finger 327 is directed to the rear side of the presser foot so that the upper ply is folded back on itself before passing under part 322 of the presser foot, the needle 12 finally stitching through the two plies to produce the opened seam referred to. Alternatively, the finger may be shaped as in Fig. 15 (not shown), to produce the seam made by the first embodiment. The presser foot 314 comprises three sections 321, 322 and 333, each of which is separately biased downwards by a respective spring. Specification 779,132 and U.S.A. Specification 2,448,495 also are referred to.