TENSIONER FOR THE HEADER OF A HARVESTER

摘要

A chain or belt tensioner is provided in a header for a harvester having a pair of rollers, each supported on separate pivot arms and engagable with the slack and taut strands of the chain or belt. The pivot arms are mounted about a common pivo t and are spring biased into engagement with the chain or belt by a common spring. Whe n the drive direction is reversed, the normally slack side of the chain becomes taut and assumes a straight-line position between the sprockets or sheaves. The pivot arms will rotate about the pivot and the pivot arm on the strand that has now become slack will rotate to tension the slack strand. The biasing spring coupled to the two pivot arms biases the rollers against the two strands of the chain and provides a fixed tensioning force on the chain that does not require adjustment.