Patent ID: 7111625

Claim:
A demand valve having a movable diaphragm and valve means operable by movement of the diaphragm from a first position wherein the valve means is closed to a second position wherein the valve means is opened to supply gas to a user, the demand valve comprising: a housing; a resilient latching arrangement operable to retain the diaphragm in the first position, wherein the resilient latching arrangement comprises: a first detent mounted to the diaphragm; the second detent mounted to the housing and facing in the opposite direction to the first detent; and a resilient swinging arm pivotally mounted to the housing for swinging movement between a latched position and a released position; and wherein: in the latched position the resilient swinging arm engages the second detent to retain the resilient swinging arm in the latched position and the resilient swinging arm engages the first detent to retain the diaphragm in the first position wherein the valve means is closed; in the released position the resilient swinging arm is disengaged from the second detent and the diaphragm is free to move to the second position in which the valve means is opened; the arrangement being such that the resilient latching arrangement is released when the diaphragm is exposed to a predetermined pressure differential; the resilient swinging arm comprises two spaced cantilever arms spreadable away from each other against resilient force; and the second detent comprises a pair of divergent inclined surfaces engageable with respective ones of the cantilever arms.