Abstract: For improving the cooling of the rotor armature disk (2) of an electromagnetic retarder, connected to an outer flange (10) by a circle of arms (9) forming ventilation fins, these arms are formed by two parallel dividing walls (12) defining a narrow elongate pocket (13) whose bottom is formed by the disk and which opens axially into the free face of the flange through a slit (14) formed in this flange.

Abstract: In vehicle retarding equipment having an eddy-current retarder with four windings, a battery, four control contactors, a five position actuating member and a multiple contactor for under-energizing the retarder by connecting the windings thereof in series, two by two this latter contactor is automatically controlled by opening an appropriate contact, when the real braking torque is reduced to a third of its nominal value at cold, this control being slaved either to the temperature of the rotor armature of the retarder, through a thermocontact mounted in a pocket formed in a pole-shoe of the stator opposite said armature, or to the shifting of the gear box to a low gear position, or to the time during which the actuating member is in its position corresponding to maximum energization.

Abstract: A circuit is provided for thermally regulating a vehicle equipped with an electric retarder (2), using the forced circulation of a liquid successively through the engine (1,5) of the vehicle, a radiator (7) and a drive pump (6). An auxiliary circuit section (10) is provided comprising a heat exchanger (11) adapted to remove heat coming from the retarder or to yield up heat to the air current thrown back by the rotor of this retarder and a three-way electro-magnetic valve (12) adapted to bring this section (10) into circuit depending on whether the retarder is energized or not and/or whether the temperature of the liquid in the radiator exceeds a certain threshold or not. A second auxiliary circuit section (15-17) allows the passenger space of the vehicle to be heated.

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.