Abstract: For automatically neutralizing the energization of a speed reducer adapted to brake an axle of a heavy vehicle, when the deceleration of this latter exceeds a predetermined threshold, the movements are used of a mass, such as a drop of mercury, adapted to ascend under the effect of its inertia a ramp inclined with respect to the axis of the vehicle by an angle A whose tangent is equal to (m/M) tg .alpha., M being the total mass of the vehicle, m the mass applied to the braked axle and tg .alpha. the coefficient of adhesion between the wheels of this axle and the ground.

Abstract: The invention concerns speed reducing equipment for vehicles, comprising an eddy current speed reducer itself comprising four inductor windings, a battery, and control means actuated by a five-position lever.Safety means are provided for automatically preventing the maintenance of the energization of the speed reducer corresponding respectively to positions 4 and 3 after respectively time delays of the order of 20 seconds and 3 minutes and the inductor windings are reinforced so that they may generate a number of ampere-turns greater than that which they are usually capable of producing, which makes it possible to obtain high torques when cold for a speed reducer of given dimensions.

Abstract: The invention relates to control devices for electrical, hydraulic or other forms of decelerator for heavy vehicles. For the purpose of avoiding skidding of the wheels of the vehicles when empty, in the case of a false maneuvre by the driver, the devices comprise means for automatically neutralizing the brake when the deceleration of the vehicle exceeds a predetermined level of the order of 1-3 m/s.sup.2.

Abstract: Apparatus for hydraulic control of friction brakes of an automobile vehicle which comprises a first master-cylinder directly connected to the hydraulic brake circuit and operated by the driver's brake pedal and a second master-cylinder operated by release of the gas pedal, and connected to the first master-cylinder in place of the reservoir thereof. The first master-cylinder is a tandem master-cylinder which comprises a first piston connected by the intermediary of a linkage to the brake pedal and a second piston dividing the interior of the first master-cylinder into first and second chambers. The first chamber is located between the two pistons and is connected to a first hydraulic brake control-circuit, while the second chamber is situated at an end of said cylinder and is connected to a second hydraulic brake control-circuit. The two chambers are supplied with liquid.

Abstract: The invention concerns an eddy-current retarder whose stator comprises a ring of electro-magnets mounted on a transverse common support 4, each electro-magnet comprising a core surrounded by a coil of wire 2. Each coil 2 is entirely enveloped in a case of hard insulating material moulded thereon and this case is wedged angularly on support 4 by cooperation of bosses 7 moulded therewith and notches 6 or other depressions hollowed out in support 4.

Abstract: A vehicle hydraulic braking installation includes a main master-cylinder 1 operated by the driver's brake pedal with or without servo-assistance and an additional master-cylinder 13 which is operated when the driver releases the accelerator pedal. The additional master-cylinder is connected to the braking circuit only through the main master-cylinder. As soon as the main master-cylinder begins to be operated, the main master-cylinder cuts off any communication between the additional master-cylinder and the braking circuit.

Abstract: A control device for an eddy current retarder having a plurality of energizing windings comprises an insulating support carrying a plurality of connecting terminals for connection to the retarder windings and a junction terminal for connection to one pole of a power supply. A plurality of contactors are provided for controlling the energizing of the retarder windings, each contactor corresponding to a connecting terminal and comprising first and second fixed contact members, a bridge contact co-operating with the first and second fixed contact members, and a pull-on contactor winding controlling the bridge contact. A first contact plate connects the first contact member of each contactor to the corresponding connecting terminal and a second common contact plate connects the second contact members of the contactors to the junction terminal. Each contactor winding is connected to a respective control terminal which is connected to a control selector for consecutively energizing the control terminals.

Abstract: A hydraulic retarder for braking a shaft has a rotor comprising a rotor shell mounted on the shaft end and rotatively movable relative to a stator shell forming part of a stator enclosing the rotor. The shaft end projects from a housing upon which the stator is mounted by an apertured structure surrounding a driving pulley mounted on the shaft end. The apertured structure comprises lugs on the housing and a toothed ring on the stator, the teeth in the ring co-operating with the lugs so as to hold the stator centred on the axis of the shaft end irrespective of the angular position of the stator. Recesses between the teeth of the ring are disposed and dimensioned so that they provide the necessary openings for moving an endless belt into or out of the structure simply by moving the stator through an angle.