Hinge with a locking device

Claim 1

A hinge comprising: a hinge arm; a hinge casing; a first hinge link having first and second opposite ends, said first end of said first link being connected to said hinge arm by a first axle, and said second end of said first link being connected to said hinge casing by a second axle; a second hinge link having first and second opposite ends, said first end of said second link being connected to said hinge arm by a third axle, and said second end of said second link being connected to said hinge casing by a fourth axle; said first and second links cooperating to form a quadrangular linkage connecting said hinge casing to said hinge arm, such that said hinge casing is movable about said quadrangular linkage between an open position and a closed position; one of said hinge links having a first oblique surface which extends in a plane which is non-parallel to the axes of said axles; a pressure lever having a second oblique surface which is complementary to said first oblique surface and which extends in a plane which is non-parallel to said axes of said axles; said pressure lever being mounted for sliding movement axially of at least one of said first and third axles between a first position at which said first and second oblique surfaces are aligned and in mutual contact, thereby retaining said hinge casing in said closed position thereof, and a second position at which said first and second oblique surfaces are out of alignment and mutual contact; spring means operatively positioned for urging said pressure lever from said second position thereof to said first position thereof; and movement of said hinge casing from said closed position thereof to said open position thereof causing said first oblique surface of said one hinge link to be cammed against said second oblique surface of said pressure lever, thereby moving said pressure lever from said first position thereof to said second position thereof against the force of said spring means.