Robinet à gaz

摘要

The gas tap consists of a housing (10) with an inner valve (24) which seals against a seat (26). A handwheel (36) is used to operate the valve and a stem (22) transmits the movement of the handwheel to the valve. The valve is situated so that it is held against the seat by the pressure of the gas, while the handwheel is equipped with a double-threaded bush (38). The bush has one thread which causes it to move axially when rotated by the handwheel and another which runs in the opposite direction and has a different pitch to modify the effect of the first thread on the valve.