Abstract: A device for engaging and releasing of wheels by fluid control, applied in vehicles equipped with more than one drive shaft, and with hydraulic, pneumatic or vacuum system responsible for its operation, with such device being mounted within a housing (1) fixed to the wheel hub (2) of the vehicle, within which there is the engaging hub (4) with a serrated portion (4') coinciding with the inner teeth (6') of the engaging element, surrounded by a spring (7); in front of the engaging element (6) there is a cam (8), the inner face of which has a channel (9) in which the studs (10) provided in the outer edge of the cam following part (11) move, with the cam following part being kept in contact with the driving element (12) of the device due to the action of an engaging spring (13) with the cam (8) being mounted directly on the housing (1) or being surrounding the guiding ring (14), provided with horizontal grooves ( 14').

Abstract: A diaphragm control is disclosed for a free-wheeling hub assembly that selectively engages a four-wheel drive. A venting arrangement is disclosed for the diaphragm chamber of the free-wheeling hub assembly. The venting arrangement extends through the body of the free-wheeling hub assembly to a space within the engine compartment of the vehicle thus ensuring that the vent will not become clogged thus preventing the venting of the diaphragm chamber. Venting of the diaphragm chamber is important in predicting the pressure within the diaphragm chamber and thus the engagement of the free-wheeling hub assembly.

Abstract: The device for disconnecting the wheels from a vehicle's optional drive is mounted inside the support of the axle shaft, and the wheel hub is splined onto the axle shaft. The universal joint is diametrically positioned in relation to the support of the axle shaft by a bearing. The universal joint has an internal splined section which corresponds to an internal splined section on the clutch disc for "engage" and "disengage" positions. A fluid responsive actuating device is provided including a movable member in the form of a diaphragm or a piston connected to the clutch disc for axially moving, in response to the pressure or pressure differential from a fluid source to effect the engagement and disengagement of the clutch disc splines in relation to the axle shaft and universal joint splines.