Patent ID: 6050914
Filing Date: 2000-04-18
Classification: F16H

Abstract:
For a chain drive assembly having at least one driving side sprocket and at least one driven side sprocket, and a chain stretched between the sprockets with a tension run on one side of the driven sprocket and a slack run on the opposite side of the driven sprocket, a chain tension releasing device having a shoe surface and a biasing means positioned to produce a biasing force pushing said shoe surface against the tension run of the chain from an outer side forming a bowed surface of the chain in the tension run,wherein said biasing means comprises a fixed housing mounted adjacent the tension run of the chain, a plunger mounted in said housing for orthogonal movement relative to the direction of travel of the chain in the tension run, said plunger having an inner surface at its outer end, said housing having an outer surface, said outer surface positioned to engage the inner surface of said plunger to stop inward displacement of said plunger at a given advanced position of said plunger, said shoe surface being mounted at the inner end of said plunger beyond the inner surface of said plunger, and a compression spring seated between said plunger and said housing urging said plunger inwardly to the advanced position when tension of the chain at the tension side is a prescribed value or less, the shoe surface being held to the advanced position where the tension side of the chain is bowed by the biasing force of said biasing means, said inner surface of the plunger engaging said outer surface of the housing to prevent further inward displacement of the plunger, and when the chain tension exceeds the prescribed value, the tension side of the chain being straightened against the biasing force of said compression spring so that the shoe surface retreats from the advanced position.