Patent GB-871717-A (GB)
Title: Improvements in or relating to shoe upper conforming machines
IPC: A43D21/12
Filed: 1957-02-21
Abstract: 871,717. Shoe-making machine tacking mechanisms. BRITISH UNITED SHOE MACHINERY CO Ltd., and CHOICE, F. C. Feb. 20, 1958 [Feb. 21, 1957], No. 5843/57. Class 89(3) In a shoe upper conforming machine tacks on their way to the work are driven by a tack driver between a pair of tack controlling fingers which are restrained against opening during a predetermined part of each cycle of operation of the machine. In Fig. 4 a tack delivered by compressed air along a passage 224 in a pivoted tack conductor 220 passes through a tack passage 55 in a tack block 62 into a tack receiving pocket 252 formed between closed tack controlling fingers 240 provided in a recess 242 in the underside of a wiper 194. The tack controlling fingers 240 are pivoted about members 248, 250, Fig. 2 and are normally held closed by a wedge member 256 located between the tails 260 of the fingers 240 and carried by a lug 258 on the tack conductor 220. As the tack driver 98 is impelled upwards to drive the tack in the pocket 252 the end portion of the driver engages a cam face on the tack conductor and swings the tack conductor about its pivot 70 so as to withdraw the wedge 256 from between the tails 260 to allow the fingers 240 to open to permit passage therethrough of the tack. During their initial opening movement the fingers 240 are frictionally restrained from opening unduly by an upwardly spring loaded poppet 264 positioned between the tail portions 260 and having a frusto-conical head 268 the conical part of which receives inclined faces 270 on the undersides of the inner portions of the tail portions 260. When the inclined faces 270 have ridden over the conical part of the poppet head 268, flat faces on the tail portions ride over a flat upper face of the poppet head to provide a reduced restraining force to allow the fingers to open far enough to permit passage of the tack head between them. The driver 98 is one of a pair in a double tacker unit which is associated with a single tacker unit in a side tacker assembly. The single tacker unit, which includes a side plate 50, Fig. 2, and the double tacker unit, which includes a side plate 60, are mounted in the side tacker assembly for movement towards or away from the shoe edge and are interconnected by a centrally pivoted lever 172 having outwardly spring urged ball ended plungers 178 engaging cup-shaped recesses in the plates 50, 60, so that they are constrained for equal but opposite movements towards or away from the shoe edge, which in combination with a stop member 186 on each unit, enables the tacker units to automatically position themselves in accordance with the outline of the shoe bottom when the side tacker assembly is swung towards the shoe. Upon return of the side tacker assembly the tacker units are centralised by a fixed frusto-conical pin 200 engaging tail portions 206 on the lever 172. The single tacker unit is also mounted for adjustment relative to the double tacker unit in a direction heightwise of the shoe, to ensure a " tight-wipe " in the event of the shoe bottom having heightwise curvature. To allow for variation in height of the single tacker unit the slide 106 Fig. 3 which carries the driver 104 is coupled to the driver bar 90 by means of yieldable plunger 118. By disconnecting the ball ended plunger 178 of the lever 172 from either of the recesses in the plates 50, 60, the associated tacker unit can be retracted to detach the driver slide 96 to 106 from the driver bar 90 or plunger 118 respectively, to allow removal of the driver slide in order to replace a driver. The apparatus is intended for driving tacks with shanks shorter than <SP>5</SP>/ 16  inch. Specifications 550,831 and 712,654 are referred to.