US 5,839,304 A · Locking device for a parking brake

Abstract

A locking device for a parking brake on a bus having air brakes prevents accidental release of the parking brake when a sensing switch indicates that the bus should not move (e.g., when the driver is absent from the driver's seat, or a passenger-access door is open). The locking device of the invention is affixed to a portion of the bus adjacent a parking brake air valve that has an air valve shaft moving along its axis between a fully extended position, in which the valve is in a brake-applied status, and a frilly retracted position in which the valve is in a brake-released status. The locking device has a locking arm moving between a locked position in which it prohibits the parking brake valve shaft from moving into the fully retracted position and an unlocked position in which it does not affect the motion of the valve shaft. Conventionally, the valve shaft has a knob on the end distal from the valve body, and the locking arm in the locked position, prevents the knob from being pushed in all the way. Because this arrangement does not require opening the brake lines, but instead merely limits the motion of an existing moving part, the locking device does not become part of the manufacturer's brake system, nor does it affect that system's certification to meet applicable motor vehicle safety standards.

Claims11

Dependent claims

In a vehicle having a parking brake adapted to be manually engaged by an operator moving a shaft of a parking brake valve from a retracted position wherein the parking brake is disengaged to an extended position wherein the parking brake is engaged, the parking brake valve fixedly attached to a body of the vehicle, a protrusion extending radially outward from the shaft adjacent an end thereof distal from a body of the valve, an improvement for prohibiting the parking brake from being disengaged during the persistence of a predetermined condition, the improvement comprising:

means for attaching an electromechanical actuator and a locking member to the vehicle adjacent the parking brake valve;
a source of electric power for energizing the actuator;
and
a sensing switch for sensing the persistence of the predetermined condition;
wherein the electromechanical actuator is operably connected to the locking member so that, when energized, the actuator moves the locking member from an unlocked position wherein the locking member is not interposed between the protrusion and the body of the valve into a locked position wherein the locking member is interposed between the protrusion and the body of the valve, thereby prohibiting the shaft from attaining die retracted position.

2 more elements

A method of keeping a parking brake on a vehicle in a brake-applied state during the persistence of a predetermined condition that begins subsequent to an operator of the vehicle placing the brake in the brake-applied state by pulling a knob attached to a parking brake shaft from an initial brake-released position rearwardly of a body of the vehicle, the method comprising the steps of:

(a) initiating, by means of an act by the operator, the predetermined condition;
(b) sensing, by means of a sensing switch, the predetermined condition;
(c) energizing, responsive to the sensing switch sensing the predetermined condition, an electromechanical actuator operatively connected to a locking member, whereby the locking member moves into a locked position adjacent the shaft, the locking member in the locked position cooperating with the knob to prohibit the shaft from moving into the brake-released position.

Dependencies are inferred from the claim text.

Locking device for a parking brake

Life of this patent

Locking device for a parking brake

Life of this patent

Abstract

Claims11