Brake load sensing and control device

Claim 2

A load control device for a brake having a moving member associated with a wheel for coordinated movement with said wheel comprising a housing carrying a friction member and a fluid actuated piston and cylinder means for causing said friction member to engage said moving member at varying pressure in proportion to the fluid pressure exerted upon said piston, said housing including means for guiding movement of said friction member from a first position to a second position in the general direction of movement of said moving member when said friction member is engaged with said moving member, biasing means normally locating said friction member in its first position, said biasing means being yieldable to permit said friction member to shift into its said second position as relative movement between said friction member and moving member ceases during engagement of said friction and moving members, valve means associated with said friction member and movable therewith when said friction member shifts from its first into its second position for reducing the fluid pressure exerted upon said piston to permit relative movement between said friction member and said moving member.

Claim 3

The load control device of claim 1 wherein said valve means comprises a spool valve shiftably carried within a receiving chamber in said housing, one end of said spool valve being operatively associated with said friction member so that movement of said friction member from its first into its second position causes a correlated movement of said spool valve within said receiving chamber, said housing and spool valve cooperating when said friction member is in its first position to define passage means communicating with said piston and cylinder means and receiving chamber and through which actuating fluid passes to said piston and cylinder means for increasing the fluid pressure upon said piston, said housing and spool valve cooperating when said friction member is in its second position in restricting said passage means to reduce the fluid pressure upon said piston.

Claim 4

The load control device of claim 2 and including a brake shoe engageable with said wheel, a second piston and cylinder means for causing said brake shoe to engage said moving member at varying brake loads correlated to the pressure between said friction member and moving member.

Claim 5

The load control device of claim 1 wherein said housing has a receiving chamber formed therein, a shiftable valve seat member positioned within said receiving chamber, said valve seat member and housing defining passage means in communication with said piston and cylinder means for permitting actuating fluid to enter said piston and cylinder means and increase the fluid pressure exerted upon said piston, said valve means including a valve part shiftable into contact with said valve seat member to block said passage means when said friction meMber shifts into its second position.

Claim 6

The load control device of claim 4 and means permitting shiftable movement of said valve seat member within said receiving chamber upon contact of said valve part, said shiftable movement of said valve seat member causing an increase in volume in said passage means between said valve seat member and said piston and cylinder means to reduce the fluid pressure upon said piston, said biasing means being carried by said valve seat member, second biasing means for resisting shiftable movement of said valve seat member upon valve part contact until said friction member and movable member engage and rotative movement between said friction and movable members ceases.

Claim 7

The load control device of claim 2 wherein said passage means communicating with said piston and cylinder means and receiving chamber serves to permit accumulation of actuating fluid in said receiving chamber behind said spool valve at its opposite end to assist said biasing means in locating said friction member in its first position.

Claim 8

A load control device for a brake having a moving member associated with a wheel for coordinated movement with said wheel comprising a housing having a shiftable friction member engageable with said moving member for the purpose of applying a braking force to said wheel, fluid actuated piston and cylinder means for causing said friction member to engage said moving member at varying pressures in proportion to the fluid pressure exerted upon said piston, said housing including means for guiding reversible movement of said friction member from a first to a second position in the general direction of movement of said moving member when said friction member is engaged with said moving member, biasing means normally locating said friction member in its first position, said biasing means being yieldable to permit said friction member to shift into its second position as relative movement between said friction member and moving member ceases during engagement of said friction member and moving members, valve means associated with said friction member and movable therewith from an open position toward a flow restricting closed position when said friction member shifts from its first into its second position for reducing the fluid pressure exerted upon said piston to permit the resumption of relative movement between said friction member and said moving member.

Claim 9

A load control device for a brake having a moving member associated with a wheel for coordinated movement with said wheel comprising a housing having a shiftable friction member engageable with said moving member for the purpose of applying a braking force to said wheel, fluid actuated piston and cylinder means for causing said friction member to engage said moving member at varying pressures in proportion to the fluid pressure exerted upon said piston, said housing including means for guiding reversible movement of said friction member from a first to a second position in the general direction of movement of said moving member when said friction member is engaged with said moving member, biasing means normally locating said friction member in its first position, said biasing means being yieldable to permit said friction member to shift into its second position as relative movement between said friction member and moving member ceases during engagement of said friction member and moving members, valve means associated with said friction member and movable therewith from an open position toward a flow restricting closed position when said friction member shifts from its first into its second position for reducing the fluid pressure exerted upon said piston to permit the resumption of relative movement between said friction member and said moving member.

Claim 10

The load control device of claim 7 wherein said housing has a receiving chamber formed therein, a shiftable valve seat member positioned within said receiving chamber, said valve seat member and receiving chamber defining passage means in communication with said piston and cylinder means for permitting actuating fluid to enter said piston and cylinder means and increase the fluid pressure exerted upon said piston, said valve means including a valve part shiftable into contact with said valve seat member to block said passage means when said friction member is shifted into its second position.

Claim 11

The load control device of claim 8 and means permitting shiftable movement of said valve seat member within said receiving chamber upon contact of said valve part, said shiftable movement of said valve seat member causing an increase in volume in said passage means between said valve seat member and said piston and cylinder means to reduce the fluid pressure upon said piston, said biasing means being carried by said valve seat member, second biasing means for resisting shiftable movement of said valve seat member upon valve part contact until said friction member and movable member engage and rotative movement between said friction and movable members ceases.