| 摘要 |
An operating mechanism for a gas valve e.g. for use in a pre-payment gas meter or other gas supply system includes a cam (20), a cam follower (22) and an operating arm (26) mounted for movement with the gas valve mechanism so that movement of the operating arm (26) operates the gas valve mechanism to control the flow of gas. The cam follower (22) is coupled to the operating arm (26) by means of a solenoid actuator (28) operable to move the cam follower (22) from a first position relative to the operating arm to a second position relative thereto. In the first position, the cam follower (22) does not contact the cam (20). In the second position, the cam follower (22) engages the cam (20). The cam (20) is rotatable manually and when the cam follower (22) is in the second position causes the cam follower (22) and, hence, the operating arm to move to operate the gas valve mechanism. When the cam follower (22) is in the first position, rotation of the cam is ineffective. A pull-action or push-action solenoid actuator may be used. |
