GB1225841A - - Google Patents

Abstract

1,225,841. Stretching devices. DENNISON MFG. CO. Ltd. 17 April, 1968, No. 18133/68. Heading B5A. A device for stretching injection moulded fastenings, each of which consists of a filament 1, a head 2 and a bar 3, comprises a series of cross-bars 16 carried between a pair of spaced apart rotating chains (not shown). Each crossbar carries a pair of transversely slidable shoes 26 and 27 which are guided by longitudinally extending track cams and which carry normally closed jaws 36 and 37. Fixedly mounted centrally of each cross-bar is a pair of lower jaws 63, 64 adapted to co-operate with jaws 61, 62 carried by a rotating chain 51 mounted above, and intermediate the ends, of the cross-bar carrying chains. In operation, batches of fastenings interconnected by sprues 8, 9 and 10 are fed to the feed end of the cross-bar carrying chains and are engaged by jaws 36, 37 which have been temporarily cammed open by stationary cams located in advance of the chain 51. The fastenings are then fed under chain 51, where they are engaged by jaws 61 and 62, and then through a region in which the cam tracks guiding the shoes 26 and 27 are made to diverge. Each pair of jaws 36, 37 is thus moved away from its associated pair of jaws 61, 63 or 62, 64 and the filaments are stretched. Finally the stretched filaments are fed through a station at which the track cams converge and are released from the jaws by movement of chain 51 and a second temporary opening of the jaws 36, 37 by stationary cams located beyond chain 51.