Navistar International Transportation Corporation

Michael J Lehman

Brad A Hively

Terry E Hively

Roy S Zeitlow

Robert L Douglas

Richard B Davis

Burnell L Bender

David A Schaller

Anthony J Kraft

William R Heign

Charles D Sims

A circuit for the electrical system of an automotive vehicle, such as a truck, interfaces a two-speed axle selector switch (,) and a two-speed axle solenoid (,) with the vehicle ignition, or key, switch (,), the vehicle brake actuation switch (,), and the vehicle transmission neutral switch (,) to allow the axle to be shifted between its two speed ranges under certain conditions and to disallow such shifting under other conditions. The circuit includes a high range relay (,), a high range enable relay (,), a high range disable relay (,), and a low range relay (,).

Controlled two-speed axle shifting with automatic transmission

A parking brake lock-in key switch system for a truck or bus brake system. The system has two parking brake lock-in valves. One parking brake lock-in valve is installed in the air line piping between the primary air tank and the push pull double check valve and the second parking brake lock-in valve is in the air line piping between the secondary air tank and the push pull double check valve. The parking brake lock-in valves are air operated valves which when closed will look in actuated parking brakes. The parking brake lock-in valves are operated by a solenoid operated pilot valve which provides air from an air supply to close the lock-in valves when the ignition key is moved to the 'off' position. An actuated parking brake will be locked in because new air from the respective tanks will be prevented from flowing to the push pull double check valve and hence the brake chambers. The parking brake lock-in valve does not vent off downstream piping when it closes. Should the ignition key be positioned to the 'off' position with the vehicle in motion and the parking brake actuator is not engaged in the park position, air will be locked in the air line piping between the parking brake lock-in valves and the individual brake chambers including the piping in which the push pull double check valve is installed. This locked in air will prevent the brake chambers from locking the wheels, hence preventing inadvertent engagement of the parking brakes. One embodiment of the invention for vehicles with automatic transmissions will include an automatic apply-automatic release parking brake system which operates alone or in parallel with the parking brake lock-in key switch system. The automatic apply-automatic release parking brake system has a valve that acts to operate and engage the parking brake when the automatic transmission is placed in the &ldquo;Park&rdquo; position. The valve of the automatic apply-automatic release parking brake system in this embodiment will deactivate and release the parking brake when the transmission shifter is moved out of the &ldquo;Park&rdquo; position and the engine of the vehicle is running.

Parking brake lock-in key switch system for vehicle air brake system

A parking brake lock-in key switch system for a truck or bus brake system is disclosed. The system has two parking brake lock-in valves. One parking brake lock-in valve is installed in the air line piping between the primary air tank and the push pull double check valve and the second parking brake lock-in valve is in the air line piping between the secondary air tank and the push pull double check valve. The parking brake lock-in valves are air operated valves which when closed will lock in actuated parking brakes. The parking brake lock-in valves are operated by a solenoid operated pilot valve which provides air from an air supply to close the lock-in valves when the ignition key is moved to the `off` position. An actuated parking brake will be locked in because new air from the respective tanks will be prevented from flowing to the push pull double check valve and hence the brake chambers. The parking brake lock-in valve does not vent off downstream piping when it closes. Should the ignition key be positioned to the `off` position with the vehicle in motion and the parking brake actuator is not engaged in the park position, air will be locked in the air line piping between the parking brake lock-in valves and the individual brake chambers including the piping in which the push pull double check valve is installed. This locked in air will prevent the brake chambers from locking the wheels, hence preventing inadvertent engagement of the parking brakes.

A system for selectively locking a steering-column-mounted transmission shifter in a park position that places the transmission in one of two neutral positions. An electrically operated shift lock releasably locks the shifter in park position. The shift lock is under the control of an electric circuit that contains first and second shift lock relays having normally open contacts connected in series to the shift lock. The electric circuit operatively couples the relays' coils with the ignition switch, a transmission neutral position sensing switch, and a service brake sensing switch. When the service brakes are applied and the ignition switch is on, the shift lock is operated to release the shifter, allowing the shifter to be moved to other positions.

Park position locking system for steering column transmission shifter

A driver-controlled differential lock control system allows vehicles with automatic, electronic and single range manual transmissions and air pressure actuated differential locking devices to have the vehicle differential thereof locked on only at low speeds. The control system includes a vehicle speed sensor, such as a speedometer transmitter, and a speed switch responsive to the vehicle speed sensor to selectively actuate a normally-closed air solenoid valve disposed in a vehicle air supply line upstream of a manually controlled air valve which supplies the differential lock actuator. The speed switch normally supplies power to the air solenoid valve until the speed of the vehicle exceeds a predefined limit whereat power is discontinued to the air solenoid valve causing disengagement of the differential lock.

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Fort Wayne, IN, United States of America

Michael J Lehman