Patent GB-1482562-A (GB)
Title: Sewing apparatus
Inventor: BOSER RONALD J
IPC: D05B35/06
Filed: 1974-10-01
Abstract: 1482562 Sewing fastener tapes B & W MFG CO INC 1 Oct 1974 [2 Oct 1973] 42580/74 Heading DIG Apparatus, (Figs. 1 and 4), for sewing a pair of tapes of a sliding clasp fastener chain to respective portions of an article having an opening between the portions which are joined at a terminal point at one end of the opening, comprises a pair 92 of stitch forming means each including a needle, means for feeding the tapes and the portions through the stitch forming means to form parallel seams each securing a tape to a respective portion, manual control means 614 for starting the stitching and feeding, means 88 sensing the terminal point of the opening and automatic control means respective to means 88 to stop the stitching and feeding. General Operation The article (69, Fig. 3 not shown) is placed on cover 81 and passed to the guiding mechanism 84 where it is fed by the normal feed dogs to the needles to be sewn to fastener chain 68 let out from spool 846 by a motor controlled by the known tension device 852 and fed up a curved guide to the sewing position. When the terminal point of the article opening operates 88 (lever 601) to stop the sewing short of the terminal point a cutter 89 severs the fastener chain. The machine then continues to sew the seams until the end of the severed chain is sensed by means described below. One (left) needle 93 is then retracted, the feed dog lowered and a transverse feed plate operated for needle 94 to sew a seam across the fastener and back to avoid the use of an end stop. The presser foot is then raised and threads severed, the upper threads being trapped. A pneumatic control system (Figs. 52, 53 not shown) which carries out the program is described. Folding Work, Work Guides The article guiding mechanism 84 (Figs. 4 and 28) comprises seam allowance folding plates 532, 533 movable towards and away from each other pneumatically by linkge 548; 552, 553, 557. Each plate has a seam closing tip 539 or 540 biassed by springs 541; the plates extend towards and into a double scroll guide of flexible portions 560-563 adjustable for size or capacity by a split block device (Figs. 29-31 not shown). The curved fastener feed and guide 82 comprises a back plate 804 with two front plates 810, 812 spaced therefrom to provide a gap receiving the fastener string and a spring advancing member 826, (Fig. 39) reciprocated by a piston rod to feed the fastener past spring pawls 830 and through a passageway 628 (Fig. 28) between plates 620, 622 where an adjustably positioned pair of pneumatic tubes (640, 642, Fig. 33 not shown), detects the end of the chain as described above. The Terminal Sensing Mechanism 88 comprises an arm 601 secured to a rotatable shaft 602 carrying a cam 605 operating a switch 608, while a flexible shaft 610 coupled to shaft 602 carries the manual operating lever 614 and is connected to an air valve 613. Feed by dogs; feed dog dropping; transverse plate feed; feed by needles. The needle and dog feed reversal shaft (450 Fig. 22 not shown) is movable by a pneumatic device to a position against an adjustable stop to stop the dog and needle feed. The feed lift cam 483 (Fig. 24) acting on follower 482 attached to feed bar 470 will not raise feed dog 86 sufficiently to contact the work unless air cylinder 480 is actuated to insert portion 487 of member 476 between the lift cam and its follower 482. Withdrawal of portion 487 drops the feed dog to allow an overlying transverse feed plate 226 (Figs. 6 and 7), slidable on the throat plate and apertured for the feed dog, to feed the work transversely. The plate feed is derived from a worm wheel 142 driven by worm 140 from the arm shaft pulley 114, to provide a rotating hollow shaft 144 rotatably and slidably supporting a cam 158 which can be raised or lowered by piston rod 174 to engage with a projection 152 on the shaft 144 (by means 154, 156) or with a fixed pin 168 on casing 138. The cam edge is followed by roller 196 of a bell crank lever urged into engagement therewith by air pressure in cylinder 201. A valve 180 detects the raising or lowering of the cam and a valve 186 detects the presence of a single projection 192 below the cam. A slotted disc 205 on worm shaft 122 is interposed between passages 207, 208 to sense the raised position of the needles. The bell crank lever moves axially a shaft 210 which mounts a bracket 224 attached to the feed plate 226 as well as a bracket 242 secured to a block 244 (Fig. 16) receiving guide shafts 248, 249 of a presser foot support block which is raised by a rod 256 controlled by a knee lever 106.  Disconnecting Needle Drive (Fig. 12) A hollow needle bar 274 contains two half cylinders respectively attached to needle holders 308, 310. Holder 308 is slotted to accommodate a pneumatically actuated cam 300, while holder 310 has detents 356, 358 receiving balls 304 or 306. Holder 310 is pinned to bar 274 and reciprocates therewith in a needle bar gate (280 Fig. 10, not shown). When cam 300 is lowered ball 306 enters detent 358 and needles 93, 94 penetrate work together. When cam 300 is raised as shown ball 304 enters detent 356 and needle 93 remains raised and does not enter the work during transverse stitching. Thread Cutters; End retainers (Fig. 20) Within channels formed by members 364, 366 lie snagging (hooked) blades 376, 380 moved outwards (rightwards) pneumatically to engage the upper threads, move them together and, as the blades return, draw the threads back on to a fixed blade 378 to sever them, the needle end of each thread being retained by a trapper member 434. The lower threads are cut by similar mechanism operated by cylinders 662 and 664 (Fig. 4). An upper thread tension release and thread drawer is also provided, a pneumatic cylinder 500 (Fig. 1) operating a camming arm 504 which actuates a tension release lever (508, Fig. 25 not shown). Arm 504 also mounts a thread encircling loop 516 which acts between guides 495, 496 to draw additional thread. Stopping; Fault indication. The fastener chain is provided with a piece of conductive foil (856, Fig. 41 not shown) at any defect such as a splice. The foil is detected electrically (Fig. 39, not shown) and the signal employed in a stop/start circuit (Fig. 42, not shown) and operates an indicating lamp (942) therein.