Patent ID: 8123256

Claim:
A safety lock for a cam lock fitting, comprising: a) male and female conduits adapted for being connected to each other, said male conduit having an end thereon and an external circumferential groove adjacent said end, said female conduit having an end thereon and internal circular recess disposed therein adjacent said female end, a seal being disposed in said recess, wherein said end of said male conduit contacts said seal of said female conduit when said male and female conduits are connected, first and second cam levers being disposed on opposite sides of said female conduit each having a lever portion and a cam portion wherein each said cam portion of said cam levers is adapted to rotate through a wall of said female conduit portion and into said groove so as to removably join said male conduit to said female conduit, wherein each said cam lever has a first closed position when said male and female conduits are joined together and a second open position when said male and female conduits are disconnected from each other; b) a housing being disposed external said female conduit containing a bore adjacent said first cam lever; c) said housing containing a bore communicating with said bore in said female wall extending into an interior of said female conduit; d) a piston slidable within said bores, an inward surface of said piston being exposed to pressure within said female conduit; e) a chamber formed between an outward surface of said piston and a top closure of said bore; f) a locking pin extending out through a side wall of said housing from said chamber and bore, said locking pin being slidable between a deployed position overlapping said lever portion when said first cam lever is in said closed position effectively blocking said first cam lever from being rotated into an open position and a retracted position substantially fully within said chamber allowing said first cam lever to be rotated into said open position; and g) a linkage between said locking pin and said piston adapted to move said locking pin into said deployed position when there is sufficient fluid pressure within said female conduit to move said piston outwardly thereby urging said locking pin into said locking position, said locking pin having a distal end which is adapted to be pushed to retract said locking pin when pressure drops in said female conduit and said piston moves inwardly, thereby unlocking said first cam lever.