Anti-tamper fire hydrant stopcock opener has rotary square to receive key equipped with moving feeler and inner nut to engage with lower bearing

摘要

The hydrant stopcock opener, turned by a key (1) with a square socket (11), consists of a rotary square component (21) to receive the socket, having an inner sliding feeler (24) with a nut (23) on its lower end to engage with a recess (26) in a lower bearing (25). The nut and recess have magnets or a spring to hold the nut in a normally disengaged position, the nut being engaged when the feeler is pressed down by the key.