Engageable friction wheel drive for auxiliary drive

The friction wheel drive taken from a crankshaft (1), e.g. for a vehicle motor water pump drive wheel (4), has an intermediate wheel (3) to switch it on and off. The circumference surface of the intermediate wheel has at least one friction surface (7) and at least one toothed structure (10) around it. The teeth of the intermediate wheel are constantly keyed to the outer teeth (6) of a gear shaft (11) or the water pump drive wheel on it. The intermediate wheel is mounted on a rocker (12) which is given a rotary or sliding movement to connect and disconnect the friction surface at another friction surface or a further gear wheel keyed to a shaft. The energy flow can be adjusted or interrupted between the additional shaft and the shaft constantly meshed to the intermediate wheel.