Gear has third gearwheel which acting as tensioning element offset by rotational angle in relation to second gearwheel acts upon force transmission means to keep tensioning constant and compensate for tensioning fluctuations

摘要

The gear (1) has a drive pinion (6) acting upon a flexible force transmission means such as a chain (7) or toothed belt. The force transmission means revolves around a second (8) as well as a third gearwheel, with both gearwheels having the same number of teeth. The third gearwheel, acting as a tensioning element offset by rotational angle in relation to the second gearwheel, acts upon the force transmission means in such a way that it keeps the tensioning more or less constant and compensates for tensioning fluctuations created by the first gearwheel. Independent claims are included for a muscle-powered device with a pedal or crank handle drive, and for a bicycle whereby the transmission of force to the rear wheel is taken from the driven shaft of the gear.