Parking brake assembly

Abstract

A parking brake assembly for an air actuated disc brake includes a pneumatic actuator having a push rod for applying a brake force to brake pads. The push rod is generally translatable between a rest position at which the brake force is not applied and an actuated position at which a brake force is applied. The parking brake assembly includes a clamp assembly operable to retain the push rod in the actuated position and thereby apply the parking brake. The clamp assembly is configured for fitment within a caliper housing of the brake.

1 . A parking brake assembly for an air actuated disc brake comprising: 
 a pneumatic actuator including a push rod for applying a brake force to brake pads, wherein the push rod is generally translatable between a rest position at which the brake force is not applied and an actuated position at which the brake force is applied; and    a clamp assembly to retain the push rod in the actuated position and thereby apply a parking brake, wherein the clamp assembly is configured for fitment within a caliper housing of the parking brake assembly.    
   
   
       2 . The parking brake assembly as defined in  claim 1  wherein the clamp assembly self clamps the push rod when the push rod is moved to the actuated position to apply the brake force.  
   
   
       3 . The parking brake assembly as defined in  claim 1  wherein the clamp assembly includes a clamp housing substantially fixed in an axial direction of the push rod relative to the parking brake assembly and a wedgeable element to retain the push rod in the actuated position by a wedging action between the clamp housing and the push rod.  
   
   
       4 . The parking brake assembly as defined in  claim 3  wherein the clamp housing includes a clamp housing wedge surface engageable by the wedgeable element to create the wedging action.  
   
   
       5 . The parking brake assembly as defined in  claim 3  wherein the clamp housing includes a bearing surface that allows the clamp housing to move generally in a lateral direction as the push rod moves in the lateral direction during operation.  
   
   
       6 . The parking brake assembly as defined in  claim 5  wherein the clamp housing includes lugs that provide the bearing surface.  
   
   
       7 . The parking brake assembly as defined in  claim 3  wherein the clamp housing includes a pivot arrangement that allows the clamp housing to pivot as the push rod pivots during operation.  
   
   
       8 . The parking brake assembly as defined in  claim 7  wherein the clamp housing includes lugs that provide a bearing surface of the clamp housing and the lugs provide the pivot arrangement.  
   
   
       9 . The parking brake assembly as defined in  claim 3  wherein the wedgeable element includes a wedgeable element wedge surface engageable by the clamp housing to create the wedging action.  
   
   
       10 . The parking brake assembly as defined in  claim 9  wherein the wedgeable element includes a plurality of resiliently mounted projections, and the wedgeable element wedge surface is provided on the plurality of resiliently mounted projections.  
   
   
       11 . The parking brake assembly as defined in  claim 1  further including a power actuator to release the clamp assembly and release the parking brake, wherein the clamp assembly includes a clamp housing substantially fixed in an axial direction of the push rod relative to the parking brake assembly and a wedgeable element to retain the push rod in the actuated position by a wedging action between the clamp housing and the push rod, and the power actuator moves the wedgeable element to a non-wedging position to release the parking brake.  
   
   
       12 . The parking brake assembly as defined in  claim 11  wherein the power actuator moves the wedgeable element in an application direction of the push rod to the non-wedging position.  
   
   
       13 . The parking brake assembly as defined in  claim 11  further including a pivotable lever, wherein the power actuator acts via the pivotable lever to release the parking brake.  
   
   
       14 . The parking brake assembly according to  claim 1 , wherein the clamp assembly is located within the caliper housing.  
   
   
       15 . The parking brake assembly according to  claim 14  wherein the caliper housing includes a wall and a portion of the clamp assembly is located within the wall of the caliper housing.  
   
   
       16 . The parking brake assembly according to  claim 15  wherein the caliper housing includes an opening and the portion of the clamp assembly is located near the opening in the caliper housing to receive the push rod.  
   
   
       17 . The parking brake assembly according to  claim 14  further including a power actuator to release the clamp assembly and release the parking brake, wherein the power actuator is located within the caliper housing.  
   
   
       18 . The parking brake assembly according to  claim 17  wherein the caliper housing includes a rear wall and a base wall and the power actuator is located near the rear wall and the base wall of the caliper housing.  
   
   
       19 . The parking brake assembly according to  claim 17  wherein the power actuator is located substantially along a centerline of the caliper housing in alignment with a line of action of the push rod.  
   
   
       20 . The parking brake assembly according to  claim 18  wherein the rear wall of the caliper housing includes a projection extending rearwardly to accommodate the power actuator.