Automatic retaining catch for manhole cover - consists of pawl which is held in engaged position by offset weight

摘要

A manhole cover (3) is held in place by means of a catch which is automatically engaged when the cover is placed over the manhole. The catch consists of a pawl (11) which incorporates a balance weight (18) which causes the pawl to swing outwards and engage the underside (19) of a ratchet tooth fixed to the wall of the manhole. The sloping upper faces (20) of the ratchet teeth swing the pawl (11) inwards as the cover is placed in position. The pawl can be released by a tool which is inserted through a hole in the cover. USE - Manhole covers.