Kelsey-hayes Company

David T Ayers, Jr

John S Frait

Michael D Warner

Roger E Doerfler

William Stelzer

The present invention relates to a self-contained electric brake controller for energizing electrically operated brakes in a towed vehicle in response to a demand by a driver in a towing vehicle. The controller includes a unique deceleration sensing unit for generating a signal proportional to the magnitude of deceleration of the towing vehicle. The deceleration sensing unit includes an outer housing adapted to be secured relative to the towing vehicle, and a pendulum mounted on an axis for pivotal movement relative to the housing. The pendulum is movable in one direction from a resting position to a predetermined extended position when the vehicle is subjected to a predetermined magnitude of deceleration. The pendulum includes a magnet spaced from the pivot axis of the pendulum. A detector such as a Hall Effect device is carried by the housing and is responsive to the magnetic field produced by the pendulum magnet for generating a position signal representing the predetermined extended position of the pendulum. This position signal corresponds to the predetermined magnitude of deceleration of the vehicle. The deceleration sensing unit includes a second magnet carried by the housing and spaced from the pendulum for producing a magnetic field which, as the pendulum swings to its extended position, opposes the magnetic field of the pendulum magnet to produce a restoring force to resist further forward movement of the pendulum. The deceleration sensing unit also includes a damping element constructed of a ferromagnetic material spaced from the pendulum magnet for damping undesirable movement of the pendulum. Also, the circuit responsive to the deceleration signal includes several unique features.

Deceleration sensor for an electric brake controller

An electric brake control circuit is responsive to an activation signal and a vehicle deceleration signal for generating a brake control signal representing a predetermined amount of braking. A comparator compares the voltage level of the brake control signal with the voltage level of a sawtooth waveform to produce a pluse width modulated signal having a duty cycle corresponding to the predetermined amount of braking. This pulse width modulated signal is supplied to an output driver for generating a brake driving signal to energize the brakes. The activation signal is generated at the voltage level of the vehicle power supply when the driver actuates the vehicle stop light switch. The circuit is responsive to the activation signal for disabling the output driver when the voltage level of the activation signal is below a predetermined level. The circuit also senses the current load on the brake driving signal to protect the output driver in the event of a full or partial short circuit condition. As the sensed current load progressively exceeds a predetermined level, the circuit progressively increases the average voltage level of the sawtooth waveform, thus causing the comparator to reduce the duty cycle of the pulse width modulated signal.

Electric brake controller

A generally self-contained automatic adjusting strut having many uses including that of an automatic adjuster for the shoes of a friction brake. The unit comprises a carrier having a threaded strut expansible outwardly therefrom by means of a star wheel. The star wheel is periodically rotated to compensate for wear adjustment by an adjusting lever pivoted to the carrier and containing an actuating tang that extends between two abutments on the carrier which limit the rotation of the adjusting lever to a prescribed amount, as for example, 11/2 teeth of the star wheel. The actuating tang also projects through an opening in the adjacent brake shoe, which is spaced from an abutment edge of the shoe by a prescribed distance (for example 0.040 inches) less than a companion pair of abutments on the carrier, and one of which is the return stop for the actuating tang. The unit includes a combination torsion and compression spring for holding the actuating tang against one of the companion abutments of the carrier, and a second spring is provided for biasing the carrier towards the opposite shoe. The second spring, therefore, assures that the previously described clearance is maintained between the actuating tang and the adjacent shoe.

Automatic adjusting strut

A device for varying the proportion of brake pressure delivered to the front and rear brakes of a vehicle, and including a differential area piston for decreasing the proportion delivered to the rear brakes between the first and second inlet pressures, and an additional valve assembly actuatable in response to a predetermined pressure differential between the fluid pressure delivered to the piston and the fluid pressure delivered thereby to the rear brakes so as to establish a decreasing pressure differential between the pressure delivered to the front and rear brakes.

Growing community of inventors

Birmingham, MI, United States of America

David T Ayers, Jr