Abstract: A pneumatic control device for a vehicle clutch has at least one clutch disk and includes a pneumatic cylinder operatively connected to the clutch disk operating the clutch disk as a function of pneumatic pressure applied to the cylinder. A displacement sensor measures an amount of travel of the clutch pedal and emits a signal based thereupon. An electronic package responsive to the signal from the displacement sensor outputs a control signal which follows a predetermined law as a function of the signal from the displacement sensor. A pneumatic circuit is connected to the pneumatic cylinder for supplying the pneumatic pressure thereto, the pneumatic circuit including an electropneumatic modulator which receives the control signal and outputs a pneumatic pressure as a function of the control signal.

Abstract: A pneumatic boost device includes a booster input including a manually actuatable upstream pusher and a downstream pusher positioned such that the movement of the upstream pusher towards the piston causes the upstream pusher to contact and move the downstream pusher toward the piston. A compressed gas is supplied to the cylinder such that the piston is moved in a direction away from the booster input by a system including a gas flow path having a first check valve, the first check valve being seatable on a seat moving with the downstream pusher. Movement of the downstream pusher thus applies a gas pressure to the piston which moves by an amount corresponding to that of the upstream pusher. The downstream pusher has a piston in the additional cylinder. Another gas flow path has a second check valve, the second check valve being seatable on a seat moving with the upstream pusher by movement of the upstream pusher toward the piston.

Abstract: A device designed to actuate the positive clutches of gearbox sliding gears following synchronization of the respective pairs of gears. A cylinder mechanism is provided on each sliding plate of the gearbox, as well as solenoid valves which are controlled by an electronic calculator to select and actuate the cylinders. Each cylinder mechanism includes two oppositely acting pistons, each connected to the sliding plate, and each sliding in its own cylinder which also includes a return spring which operates against each piston and which practically eliminates the clearance above the piston as the piston is about to be actuated.

Abstract: Fluid actuation device with compensation for wear, particularly for friction clutch mechanisms of the type having a cylinder in which there are placed a first piston resting on a spring and a second piston extended by a declutching control rod, and in which the space between the pistons is filled with an incompressible fluid. The cylinder carries a separation wall between two compartments which house respectively the first and the second pistons. An orifice for communication between said compartments carried by the separation wall is associated with a stopper valve rigidly connected to a membrane that is subjected to a pressure for control and transmission of a thrust force on the cylinder and for driving the control rod.