Gear change device for selectively switching on one of two ratios of a distribution- or intermediate-gearing

摘要

A gear change device for selectively switching on one of two ratios (4, 6 or 5, 7) of a distribution - or intermediate gearing (15), in particular for selectively switching on the cross-country gear in heavy-duty trucks, has a gear change element (9 to 12) which is designed as a socket (9) having a synchronising mechanism (10, 11), which socket (9) is adjustable via an actuating device (22, 23) during driving when clutch (2) is disengaged. To prevent overspeeding of the engine, a locking mechanism (26) is provided which, controlled by a speed monitor (27), only permits switching back into the cross-country gear (5, 7) if the engine speed is in a predeterminable lower range when the clutch (2) is disengaged. IMAGE