Patent ID: 9701297
Date: 2017-07-11
CPC Classifications: B60T,F16D

Claim:
1. A pneumatic brake actuator, comprising: a spring brake actuator comprising a spring chamber and a spring brake pressure chamber; a service brake actuator coupled with said spring brake actuator and comprising a service brake pressure chamber and a pushrod chamber; an actuator tube comprising a side wall that defines an interior space which is in fluid communication with said spring chamber, wherein said actuator tube comprises a first end positioned adjacent said spring chamber and a second end positioned in said service brake pressure chamber, wherein said second end presents an opening; a valve body that is at least partially positioned within said interior space of said actuator tube through said opening, wherein said valve body defines a channel; and a seal positioned within said channel in said valve body, wherein said seal and said valve body enclose a valve chamber that is not in fluid communication with said spring chamber and said service brake pressure chamber, wherein said seal is moveable between an open position in which fluid can flow through said channel between said spring chamber and said service brake pressure chamber and a closed position in which fluid is blocked from flowing through said channel between said spring chamber and said service brake pressure chamber, wherein said seal is biased to said open position, wherein said seal comprises a first surface that is in fluid communication with said service brake pressure chamber, and wherein said seal comprises a second surface that is in fluid communication with said valve chamber.