Air brake antilock control

Claim 2

In an antilock air brake system for a vehicle having means to signal the presence and absence of a lock condition at a wheel of a vehicle and a relay valve responsive to air pressure in a control line to apply and release the brakes at the wheel, the combination comprising: a wheel lock control mechanism including a housing forming an inlet connected to said control line, an outlet connected to atmosphere, and a control chamber communicating with said relay valve, passage means communicating said inlet with said control chamber, valve means having a first position in which said control chamber is open to said inlet and closed to said outlet for admitting air to apply the brakes and a second position in which said chamber is open to said outlet and closed to said inlet for releasing the brakes, solenoid means movable in response to the signal means for moving said valve means between said first and second positions, passage restricting means having a normal position adjacent to said passage means and being movable into said passage means to restrict the latter in response to a first signal from the signal means, and pressure responsive means operatively connected to said passage restricting means for maintaining the latter in said passage in the presence of air under pressure at said inlet, and independently of the movement of said valve means for reducing the flow of air from said inlet.

Claim 3

The combination set forth in claim 1 in which said passage restricting means includes a plunger slidably disposed transversely of said passage means and having an end portion movable into and out of said passage means.

Claim 4

The combination set forth in claim 1 in which said housing forms a regulating cavity connected to said passage means at a point between said valve means and said restrictor means, and one way check valve means normally closed to isolate said regulating cavity from said passage means and being movable to an open position when said valve means is in said second position to admit air from said passage means to said regulating cavity, said pressure responsive means being exposed to the pressure in said regulating cavity.

Claim 5

The combination set forth in claim 3 in which said check valve means is movable to said open position in response to movement of said solenoid means.

Claim 6

The combination set forth in claim 3 in which said pressure responsive means is in the form of a piston having a face portion exposed to the pressure in said regulating cavity.

Claim 7

The combination set forth in claim 5 in which said restrictor means is in the form of a plunger movable transversely to said passage means and in which said plunger is connected to said piston means.

Claim 8

The combination set forth in claim 3 and further comprising biasing means urging said check valve to a closed position with a predetermined force, said check valve being movable to an open position when said valve means is in said first position and in response to a pressure at said inlet acting on said check valve with a force in excess of said predeteRmined force.

Claim 9

The combination set forth in claim 3 and further comprising additional one way check valve means communicating said regulating cavity with said passage means at a point intermediate said inlet and said restrictor means, said additional check valve means being responsive to a pressure in said regulating cavity greater than the pressure at said inlet to open and release the pressure from said regulating cavity to permit said restrictor means to return to its normal position.

Claim 10

The combination set forth in claim 1 and further comprising a storage cavity formed by said housing and connected to said passage means at a point between said control chamber and said restrictor means, said storage cavity delivering air to said control chamber when said valve means moves from said second to said first position for initial rapid increase in pressure in said control chamber.

Claim 11

An antilock brake control mechanism for use with an air brake relay valve adapted to receive variable pressure control air to apply and release the brakes at a wheel of a vehicle and comprising: a housing having a control chamber adapted to communicate with the relay valve, an inlet port adapted to communicate with said variable pressure control air and an outlet port connected to the atmosphere, passage means between said inlet port and said control chamber, valve means having a first position in which said control chamber is open to said passage means for admitting air pressure to apply the brakes and a second position in which said chamber is open to said outlet port for exhausting air and releasing the brakes, solenoid means responsive to a wheel lock condition to move said valve means from said first to said second position and responsive to the end of the wheel lock condition to move said valve means from said second to said first position, a regulating cavity formed by said housing, first check valve means normally being closed and being responsive to movement of said valve means from said first to said second position to admit air from said passage means to said regulating cavity, second check valve means between said regulating cavity and said passage means and being responsive to pressure in said regulating cavity greater than at said inlet port to move from a normally closed position and release pressure from said cavity, and restrictor means including a plunger movable transversely of said passage and having a first position in which said plunger is out of said passage and a second position in which said plunger is disposed in said passage means to restrict fluid flow therein, said plunger having a pressure responsive portion in said regulating cavity responsive to pressure therein to move said plunger to said second position to restrict fluid flow from said inlet port to said control chamber.

Claim 12

An antilock brake control mechanism for use with an air brake relay valve adapted to receive variable pressure control air to apply and release the brakes at a wheel of a vehicle and comprising: a housing having a control chamber adapted to communicate with the relay valve, an inlet port adapted to communicate with said variable pressure control air and an outlet port connected to the atmosphere, passage means between said inlet port and said control chamber, valve means having a first position in which said control chamber is open to said passage means for admitting air pressure to apply the brakes and a second position in which said chamber is open to said outlet port for exhausting air and releasing the brakes, solenoid means responsive to a wheel lock condition to move said valve means from said first to said second position and responsive to the end of the wheel lock condition to move said valve means from said second to said first position, a regulating cavity formed by said housing, first check valve means normally being closed and being responsive to movement of said valve means from said first to said second position to admit air from said passage means to said regulating cavity, second check valve means between said regulating cavity and said passage means and being responsive to pressure in said regulating cavity greater than at said inlet port to move from a normally closed position and release pressure from said cavity, and restrictor means including a plunger movable transversely of said passage and having a first position in which said plunger is out of said passage and a second position in which said plunger is disposed in said passage means to restrict fluid flow therein, said plunger having a pressure responsive portion in said regulating cavity responsive to pressure therein to move said plunger to said second position to restrict fluid flow from said inlet port to said control chamber.

Claim 13

The antilock brake control mechanism defined in claim 10 and further comprising a storage cavity formed in said housing and communicating with said passage means between said restrictor means and said control chamber, said storage cavity delivering air to said control chamber when said valve means moves from said second to said first position for initial rapid increase in pressure in said control chamber.

Claim 14

The antilock brake control mechanism defined in claim 10 in which said first check valve means is responsive to pressure in said passage means in excess of a predetermined amount and in the absence of a wheel lock signal to open and admit air to said regulating cavity.