GB570909A - Improvements in tension arrangements for chain gearing - Google Patents

Abstract

570,909. Chain gearing. AVELING-BARFORD, Ltd., and PENN, O. S. Dec. 6, 1943, No. 20350. [Class 80 (i)] Consists in means for tensioning two driving chains associated with sprockets rotating about different axes supported intermediately of the driving and driven elements. A drive is transmitted from the shaft A<1> of a prime mover A to a shaft E, by chains C, D engaging sprockets on separate shafts B<1>, B<2> of a gear box B. This gear box is pivotally supported on a cross-head B<3> adjustable by a screw G along a slot in the base F, and at its upper end has an arcuate slot B<5> through which passes a clamping bolt H fixed to a support. To adjust the tensions, the bolt H is slackened and the screw G rotated to move the cross-head inwardly until arrested by the chain D, after which further rotation of screw G rotates the gear box bodily about the shaft B<2> counterclockwise to tighten the belt C, the bolt H then being tightened. In modifications, the chains C, D (1) extend from the gear box in the same direction, (2) are at an angle to one another. As applied to the transmission mechanism of a self-propelled dumper truck, the crankshaft 7 of an internal-combustion engine 6 drives through a sprocket 8, chain 9 and sprocket 10, the input shaft 11 of a gear box 12, the output shaft 13 of which drives the road wheels 3 through a sprocket 14 and chain 15. Two cheek plates 17 bolted to the gear box each terminates in a bearing boss 18 rotatably accommodating an eccentric 19 keyed on a spindle 20 supported at one end by a chassis member 2 and at the other end by a subframe member 21, and surrounded by a tubular distance piece 22. The eccentric is rotatable by an arm 23 and can be locked by nuts 24. The rear end of the gear box has pivoted thereto at 27 a yoke 28 of a rod 29 the lower end of which passes through an apertured block 30 pivoted at 31 in a bracket 32 to which it is secured by a bolt 33. To adjust the tensions, the nuts 24 and bolt 33 are slackened, the eccentrics 19 turned to tighten chain 15 and then turned still further to cant the gear box about the shaft 13 to tension the chain 9. The securing means are then tightened again, a head 20a, Fig. 7, on the eccentric spindle acting as a clamping device.