Device for controlling discharge from a pneumatic enclosure under pressure, in particular for rapid and controlled deflation of a tire

A device for controlling discharge from a pneumatic enclosure under pressure, to a predetermined pressure value after the device has been assembled to a valve fitted to the enclosure, the valve including a deflation pin, said device comprising

• a case which provides a chamber, a pushbutton slidably mounted within said case, a striker adapted to cooperate with the deflation pin of the valve when said pushbutton is pressed, at least one vent hole in said case for exhausting the gaseous fluid contained in the enclosure to be deflated and a piston-washer received in said chamber wherein said striker is slidably mounted in said piston-washer, biasing means for maintaining said piston-washer in a first position when said device is in a non-use mode, and a locking abutment projecting into said chamber so as to inhibit movement of said piston-washer at one position thereof from movement against said biasing means,
• whereby when said pushbutton is pressed causing said striker to cooperate with the deflation pin of the valve to release gaseous fluid from the enclosure at a pressure greater than said predetermined pressure value, the gaseous fluid drives said piston-washer against said biasing means and causes said piston-washer to become wedged against said striker to hold said striker in a second position until the pressure falls to said predetermined pressure value.