Patent GB-686302-A (GB)
Title: A straight-bar knitting machine and a method for operating same
IPC: D04B11/32
Filed: 1948-10-01
Abstract: 686,302. Knitting-machines. LAMBACH, F. Oct. 1, 1948. [Nov. 26, 1947] No. 25601/48. Class 74 (ii). A welt-bar of a straight-bar machine is automatically disengaged from holding means, at the end of a predetermined number of courses, and drops freely under the action of gravity on to and in to engagement with the fabric, the welt rod being subsequently automatically connected with power-driven take-up means, whereby the drawing-off of the fabric is automatically transferred to the take-up means from a welt-bar which has hitherto drawn it off the fabric. The drive to the take-up shaft 156 is transmitted through a torsion spring 170, so that the shaft may be held stationary whilst the take-up ratchet 168 is racked round : the driving stroke of the driving pawl 172 is due to the pull of a spring 180. A rod 188 is reciprocated from a needle bar shaft 192 to free, periodically, a bell-crank lever 176 carrying the pawl 172, so that the ratchet 168 will be racked round if the effort of the spring 180 exceeds that of the spring 170 and to an extent depending on that excess. At the beginning of a knitting cycle, a button 42 on a pattern chain 40 moves an abutment 92 into the path of an arm 90 racked by a cam 88 on the main cam shaft 38 and so completes a linkage by which sliding members 258 are advanced, carrying a welt-bar 252 to the hooking-up position. The linkage is then retired and disabled again, leaving the members 258 under the pull of springs 260. At the same time, a cam 112 on a shaft 108, advanced by pawl and ratchet operated from the cam shaft under control of the pattern chain, moves a member 154 to render effective take-up racking pawl 172 and a co-operating locking pawl 194. The take-up shaft 156 is, however, prevented from rotating because take-up straps 164, fastened at one end to reels 160 on the shaft, are fastened at their other ends to pulleys 274 fast on a shaft 146 bearing a collar 144 in a notch 142 of which a locking latch 136 is engaged : the result is thus merely to wind up the spring 170. As the welt bar is retracted by the springs 260, it rocks a lever 298, which, in turn, rocks a member 286, to release a welt rod 306, the ends of which, as it falls onto the fabric, enter guiding channels 314. The latch 136 is now moved, to release the shaft 146, by a cam 110 on the shaft 108, and the previously stressed spring 170 rotates the take-up shaft 156, so that hooks 278 on the straps 164 are suddenly moved into engagement with the welt-rod. The take-up is thereafter continued through the straps 164, hooks 278 and welt-rod 306, the pull of spring 180 being varied, to vary the take-up tension in accordance with fabric width, by a suitable cam bar on the right-hand carrier spindle nut which, through linkwork, adjusts the position of a rod 182 to which the spring 180 is anchored. After a time, the machine is automatically stopped for welt-turning. The welt bar 252 is now placed by hand on holding guides 316, in such a position that it does not interfere with the narrowing fingers 354, so that the turn may be effected without lifting the narrowing machine, and the needles are brought into a forwardly inclined position. At this time, a link 334 which normally transmits backward and forward movement to the knocking-over bits 318 is moved into such a position that a pin 338 on the vertical bar 328 can snap from the position shown into an adjacent recess 348. This causes the bar 322 to rock, so that the knocking-over bits can co-operate with the now inclined needles. Easy access to the knocking-over bits, when the machine is at a standstill, is provided by so moving the link 334 as to allow the pin 338 to snap into a second recess 350, when the knocking-over bar will be still further advanced. At the end of the knitting cycle, the member 154 renders the pawls 172, 194 inoperative and the latch 136 is returned to the locking position. The shape of the notch 142 is such, however, that the shaft 146 may be rotated, by means of a handle, to unwind the fabric from the take-up reel. Specification 655,451 is referred to.