Abstract: A bidirectional flow communication passageway is provided by the present invention in a multiple-circuit fluid pressure responsive system on a motor vehicle to allow a gradual reduction of pressure in a parking brake circuit which is a part of such system. The passageway is restricted to limit such bidirectional flow to a predetermined level. The pressure reduction permitted is sufficient to activate a parking brake valve in such parking brake circuit when a defect occurs in an operating service brake circuit which is also a part of such system.

Abstract: A bidirectional flow communication passageway is provided by the present invention in a multiple-circuit fluid pressure responsive system on a motor vehicle to allow a gradual reduction of pressure in a parking brake circuit which is a part of such system. The passageway is restricted to limit such bidirectional flow to a predetermined level. The pressure reduction permitted is sufficient to activate a parking brake valve in such parking brake circuit when a defect occurs in an operating service brake circuit which is also a part of such system.

Abstract: The present invention is a braking value transmitter with a pedal to modulate the braking pressure. The pedal is braced against a spring. The force exerted by the pedal or the position of the pedal is sensed by an electronic sensor. The output signal of the sensor is fed to an electronic system, which transforms the approximately linear characteristic of the sensor into a progressive characteristic.

Abstract: A level control system for motor vehicles having pneumatic springs which function in accordance with the vehicle load. A specified distance is normally maintained between the vehicle body the vehicle axle. This distance is maintained by charging or discharging the pneumatic springs. The level control system includes an air dryer and a pneumatic relay type of controllable discharge valve having a relatively large cross-sectional port by which the air dryer is connected to the atmosphere. The discharge valve operates against a spring return force. The magnitude of the spring return force corresponds to a preselected minimum pneumatic spring pressure. The system counteracts an icing action of the discharge valve and prevents an unintentional and complete discharging of the pneumatic springs.

Abstract: The present invention teaches an activation apparatus for a differential pawl. Such activation apparatus is designed to prevent damage to components of the differential pawl and/or of the drive train resulting from operator error. According to the invention, when a drive wheel slips, a first apparatus acquires a slip signal; and when a slip signal is present, a second apparatus prevents the pressurization of a pressure-medium-operated actuator apparatus of the activation apparatus.

Abstract: An apparatus which measures and regulates the braking torque of a brake unit in long-term operational use. The brake unit includes both a brakable element and the braking device. An output signal from at least one temperature-dependent measuring element, located on or in one of the brakable elements and the braking device, is supplied to an evaluation apparatus. The evaluation apparatus determines, from the current value of the output signal of the temperature-measuring element, a present braking torque, and adjusts such torque when desirable.

Abstract: A brake pressure control valve for regulating the braking pressure in the trailer brake system of a tractor-trailer vehicle, so as to develop the trailer brake pressure to a preset level ahead of the braking pressure in the tractor brake system during a pilot phase of brake operation. The preset level of this advance trailer brake pressure can be selected by an adjustable member that forms a part of the auxiliary valving that controls the point at which the pilot phase of operation is terminated. A limit stop is cooperatively arranged with this adjustable member in order to provide a means for limiting the point beyond which the auxiliary valving is activated, to thereby prevent the advance trailer brake pressure from exceeding a specified safe maximum value.

Abstract: A setpont adjuster for a brake pedal in a motor vehicle to control an electric brake system. The setpoint adjuster includes a displacement sensor and a force sensor in parallel-connection, in which the force sensor supplies the reference value. Electronic main circuits are connected subsequently to the sensors and test the signals of the sensors for reasonableness according to different criteria and control a warning light in case of a fault.

Abstract: An apparatus is disclosed for the control of brake pressure in a trailer pulled by a tractor. The apparatus includes a two-circuit controllable relay valve as the trailer control valve. The first circuit is controlled by the brake valve of the tractor with the pressure from the brake apparatus of such tractor. The second circuit can be optionally-connected to a distribution valve with a pressure medium source with a specified pressure or with atmosphere. Activation of the distribution valve is controlled so that the distribution valve connects the second circuit with the pressure medium source before or at the beginning of the activation of the first circuit. With this apparatus, the brake pressure can be increased in the brake apparatus of the trailer prior to increase of the brake pressure in the brake apparatus of the tractor. The level of brake pressure increased first in the brake unit of the trailer can be regulated by a set screw acting on the trailer control valve.

Abstract: A fluid-pressure-operated, three position working cylinder includes a cylindrical housing having a graduated bore formed therein and a movable primary piston dividing the bore into first and second pressure chambers. A movable secondary piston surrounds a portion of the primary piston and moves relative to the primary piston within the limits of a piston stop arrangement formed on opposing surfaces of the pistons. The piston stop arrangement includes an elastic stop on the primary piston which interacts with a sloped stop formed on the secondary piston so that upon initial insertion of the secondary piston onto the primary piston, the sloped stop compresses the elastic stop. The sloped stop includes a lip portion that can contact the elastic stop so as to restrain the secondary piston from further movement in one direction relative to the primary piston. A vent passage formed in the housing allows venting of the space between the two pistons.

Abstract: A level control arrangement for motor vehicles having air springs which are functionally responsive to the vehicle load. A predetermined distance of the vehicle frame from the vehicle axis can be maintained by charging or discharging the air springs. The control arrangement includes a safety valve which can be controlled by the pressure in the air springs. When the vehicle is overloaded, or if a malfunction occurs in the control apparatus of the level control arrangement, the safety valve limits the pressure in the air springs to a preselected maximum safe pressure.

Abstract: An air-drying apparatus for use with compressed air-operated systems such as, for example, a vehicle suspension system, includes a housing having an inlet portion, a drying material portion, and an outlet portion. An activation piston is disposed within the inlet portion and is influenced by an operating compressed air in an operating phase, and is movable under the influence of a regenerative compressed air to open an exhaust valve during a regenerative phase. A throttle bypass opening between the inlet portion and drying material portion allows a secondary regenerative compressed air to contact the activation piston, thereby achieving a standby phase. An inlet check valve having a deflectable sealing lip portion is also formed on the activation piston. A discharge valve is disposed in the outlet portion to control the flow of compressed air to and from the vehicle-operating systems.

Abstract: An anti-locking braking control system in which each one of at least two wheels of an axle provides a speed signal for use by a respective control channel of an electronic control unit having "modified individual wheel control" logic. A pair of control valves are connected in series to regulate the respective wheel brake pressure to obtain a "select-low wheel control" mode, the "individual wheel control" logic of the control channels assuring that the series-connected control valves are operated synchronously when reapplication of braking pressure is called for by a respective control channel.

Abstract: An antilocking system is being proposed which does not generate unplanned control signals when axle oscillations occur. To this purpose, a threshold value stage 6 for the wheel deceleration signals (-b) has an increased threshold value. After separation of the wheel velocity V.sub.R from the vehicle reference velocity V.sub.ref, this value is again decreased in stages so that a normal controlled braking process is not affected.

Abstract: Disclosed is a spring brake cylinder for use on motor vehicles. The cylinder is actuated to a release position in response to fluid pressure. The cylinder includes a spring actuator inserted between the brake cylinder base and a spring brake piston. A tensioning device is provided which mechanically acts upon the spring brake piston and facilitates adjustment of the distance between the spring brake piston and the cylinder base. The spring brake piston and the spring actuator can be assembled into a pretensioned unit outside the spring brake cylinder.

Abstract: An electronic control arrangement including a plurality of inputs and outputs, whereby the outputs are controlled in relationship with the inputs according to a predetermined program. Additionally, the outputs are coupled to another input by way of a special-function line. When the control is switched on, the external wiring is called upon to supply information regarding the state of certain controllable circuit elements. Through this, the electronic control circuit automatically checks which one of the several stored programs is appropriate under the circumstance.

Abstract: An automatic adjustment apparatus for the brake lever of a vehicle brake with a worm drive, an adjustment mechanism and a one-way coupling. The automatic adjustment of the brake lever on the brake shaft takes place by means of a one-way coupling. When there is a manual adjustment of the brake lever in the direction of the release of the brake jaws, the one-way coupling can be mechanically disengaged.

Abstract: A system for automatically overriding operator control of engine power delivered to the drive wheels of a motor vehicle when a wheel slip condition is detected during vehicle acceleration. A pneumatic actuator in the engine fuel control circuit is operated in a controlled manner to cause the engine fuel lever to initially decrease power at a relatively fast rate and then at a relatively slow rate to alleviate the wheel slip. Once the wheel slip condition is corrected, the actuator is reset in a controlled manner, which allows the fuel lever to restore engine power, initially at a relatively fast rate and subsequently at a relatively slow rate, such rate controlled adjustment of engine power during each wheel slip control cycle providing less cyclic control of the wheel slip correction process, and accordingly a smoother acceleration.

Abstract: A control apparatus is disclosed for a road vehicle, which contains a transmission control. The control apparatus includes, among other things, devices which recognize whether the vehicle is on the crest of a hill or in a valley, and whether the vehicle is travelling uphill or downhill over the crest of the hill or through a valley. For this purpose, the control apparatus includes a first devices which compares and calculates the difference between two stationary torques M.sub.stat calculated at different times which are necessary for nonaccelerating travel of the vehicle. In addition, the control apparatus contains a second devices which checks the mathematical sign of the difference .DELTA.M.sub.stat. Finally, the control apparatus contains a third devices which compares the stationary torque M.sub.stat with a specified value a.

Abstract: An overload protection and/or warning arragement for a vehicle brake which is activated by brake pressure so that overload protection and warning indication occurs essentially without any time-delay.In one embodiment of the invention, it is proposed to compare, by means of a comparison apparatus, a design brake pressure P(design) determined on the basis of a regulated variable imparted to an activation apparatus of the vehicle brake and of operating data of the vehicle and/or of the design data of the brakes and of the brake application apparatus with the actual brake pressure P(actual), and to initiate a warning signal if P(actual) differs by a specified amount from P(design).In another embodiment of the invention, it is proposed that the warning signal be initiated if the actual brake pressure produced by the existing brake pressure differs by a specified amount from a design brake force which is determined from the brake pressure and the design data of the brake and the brake-actuating apparatus.