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An air brake system augments the braking force available while parking without interfering with the operation of the parking brakes. The brake system includes a service brake, a pilot check valve and, typically, a quick release valve. The quick release valve and pilot check valve are interconnected

An air brake system augments the braking force available while parking without interfering with the operation of the parking brakes. The brake system includes a service brake, a pilot check valve and, typically, a quick release valve. The quick release valve and pilot check valve are interconnected in two alternative ways among the service and spring brake lines and the service brake cylinder. When the spring brake line is pressurized the system acts normally. However, when the pressure on the spring brake line is eliminated the pilot check and quick release valves trap the pressurized air within the service brake. This keeps the service brake for each individual wheel actuated. Pressurizing the service brake line pressurizes the service brake regardless of the condition of the spring brake line. Safety valves can be incorporated in the brake systems to insure that the pressure within the service brake chamber does not exceed a predetermined value.

대표청구항 ▼

An air service brake exhaust control system adapted for controlling the exhaust of air from an air service brake assembly, the assembly including a housing, a service chamber defined by said housing, a housing inlet formed in said housing and fluidly communicating with the service chamber, and an ac

An air service brake exhaust control system adapted for controlling the exhaust of air from an air service brake assembly, the assembly including a housing, a service chamber defined by said housing, a housing inlet formed in said housing and fluidly communicating with the service chamber, and an actuator responsive to the pressure within said service chamber, the system comprising: exhaust valve means, having an exhaust port, for fluidly connecting said housing inlet to a service brake pressure source or to said exhaust port for discharge to atmosphere; and a pilot check valve having a first port fluidly coupled to said exhaust port, a second/exhaust port fluidly coupled to said first port, check valve means for blocking fluid flow from said fluid port to said second/exhaust port, a control port, and means, responsive to the presence of a control pressure at said control port of at least a first value, for overriding said check valve means to allow relatively free flow of fluid from said first port to said second/exhaust port; whereby when said control pressure is at least said first valve and said housing inlet is fluidly connected to the service brake pressure source, fluid from said service brake pressure source is fluidly connected to said service chamber to actuate said actuator; when said control pressure is at least said first value and said housing inlet is fluidly connected to said exhaust port, said housing inlet is fluidly connected to said second/exhaust port to allow the fluid in said service chamber to be exhausted through said second/exhaust port; and when said control pressure is less than said first value, fluid flow from said housing inlet through said exhaust port and to said first port of said pilot check valve is blocked by said check valve means so the pressure within said service chamber is not dissipated by exhausting fluid within said service chamber through the second/exhaust port.