Patent ID: 8851580

Claim:
A control valve for a pneumatic braking system, comprising: a pilot signal inlet for communicating with a control pressure; a supply pressure inlet for communicating with a system supply pressure; an exhaust outlet for communicating with atmosphere; and a delivery outlet for communicating with an associated spring brake and selectively communicating with the exhaust outlet and the supply pressure inlet; wherein the supply pressure inlet communicates with the delivery outlet to deliver system supply pressure through the control valve to release the associated spring brake when a first momentary positive control pressure signal is applied to the pilot signal inlet; and the supply pressure inlet remains in communication with the delivery outlet until at least one of a second momentary positive control pressure signal is applied to the pilot signal inlet or the system supply pressure air received at the supply pressure inlet is below a predetermined pressure, wherein the delivery outlet communicates with the exhaust outlet to exhaust system supply pressure through the control valve to apply the associated spring brake.