Parking apparatus for a heavy vehicle during a loss of electrical power

A parking brake valve for a vehicle comprising:

• a valve body having (i) a first port connected in fluid communication with air inlet ports of spring brake chambers to supply air pressure to the air inlet ports to allow air pressure to be applied to a number of spring brake chambers to maintain parking brakes of the vehicle in released position, and (ii) a second port connected in fluid communication with the air inlet ports of the spring brake chambers to vent air pressure from the air inlet ports to allow air pressure from the spring brake chambers to exhaust down and thereby to apply parking brakes of the vehicle to park the vehicle in response to an electrical signal indicative of loss of electrical power;
• wherein the first and second ports of the valve body are controllable independent of each other to vent air pressure from the spring brake chambers.

A parking brake apparatus for a vehicle comprising:

• an electronic parking brake (EPB) valve having (i) a first air outlet port in fluid communication with a number of air inlet ports of a number of associated tractor spring brake chambers, and (ii) a second air outlet port in fluid communication with a number of air inlet ports of a number of associated trailer spring brake chambers;
• and
• electro-pneumatic means for, without vehicle driver intervention, venting air pressure from at least one of the first and second air outlet ports of the EPB valve to apply either tractor parking brakes associated with the tractor spring brake chambers or trailer parking brakes associated with the trailer spring brake chambers, or both.