Patent GB-736827-A (GB)
Title: Improvements in or relating to conveyor or transmission systems
IPC: B65G39/20
Filed: 1953-04-16
Abstract: 736,827. Driving-chains. CARVELL, E. R. July 15, 1954 [April 16, 1953], No. 10452/53. Class 24. [Also in Group XXX] An endless flexible conveyer or transmission member consists of plurality of pivotally connected elements e.g. the chain rollers 8, 8a, alternate ones of which are adapted to be displaced laterally to reduce the effective length of the member in one part of the system, wherein the member operates under compression and the system includes means for maintaining the elements in longitudinal alignment along part of the system, means for displacing the elements to a limited extent along another part of the system, and means for progressively reducing the displacement to restore the elements to longitudinal alignment. In one form, Fig. 1, the links of a chain are arranged in pairs 5, 6, having opposed abutments 14 adapted to come together in the collapsed condition of the chain so as to take up most of the compressive forces in the chain. Thus, while light guides 9, 10 only are required to maintain the links aligned in the portion of the chain having great effective length, light guides 23, 24, also a resufficient to guide the chain in the fully collapsed condition. Robust diverging guides 12, 12a are provided to guide the chain whilst allowing it to collapse and similar converging guides (not shown) restore the links to aligned condition. Preferably, collapsing of the links is ensured by the provision of a reciprocating cam 15a which deflects alternate rollers 8 of the chain upwards and is retracted as the intermediate rollers 8a pass. Instead of a reciprocating cam, a spring- loaded cam 35, Fig. 3, may be provided, and the chain (not shown) modified in that the pivots carrying rollers 8a are extended on opposite sides of the chain and carry further rollers on their ends which engage short guides 46, 47 of channel form to prevent rollers 8a from being deflected. Guides 23, 24 may be wholly or partially dispensed with if the links 5, 6 carry abutments 14 on both sides so that when collapsed a rigid structure is produced. In a further form, Fig. 8, the abutments are replaced by auxiliary links 119 which are provided on alternate links 106 and each of which have a recess 127 adapted to engage with roller 108 at the end of adjacent preceding link 105 when the chain is collapsed. The rollers intermediate rollers 108 are displaced by a reciprocating cam 115a and as the chain collapses rollers 126 on the ends of auxiliary links 119 engage the flared end 129 of a guide channel 128 which as the links reach the desired collapsed condition as defined by guides 123, 124 guides the rollers 126 towards the chain so that recesses 127 engage the rollers 108. Auxiliary links 119 are designed to be held in this position under the compression in the chain so that guide 128 is discontinued in the collapsed section. Links 119 return to outwardly extending position (by gravity, or spring if in horizontal plane) as soon as the chain rollers engage the converging guides at the end of the collapsed section. Guides 123, 124 may be wholly or partly dispensed with if auxiliary links 119 are provided on every link of the chain, alternate links having their rollers 126 engaging a guide 128 on one side of the chain and intermediate links having their rollers 126 engaging a guide 128 on the other side of the chain. The constructions described in Specification 653,434 can also be adapted for collapsing and extending the chain.