Overcenter hinge

Claim 1

A thermoplastic biasing spring integrally formed with first and second plate members, said plate members being hingedly connected one to the other along a first hinge line, said plate members being pivotably moveable about said first hinge line from a first position to a second position, and said second plate member having a rigid post longitudinally displaced from said first hinge line, said biasing spring comprising: a first arm and a second arm resiliently connected at one of their ends and said first arm being hingedly connected at its other end to said first plate member to form a second hinge line and said second arm being hingedly connected at its other end to the furtherest extent of said rigid post to form a third hinge line, said third hinge line being longitudinally displaced from said first hinge line whereby pivoting movement of one or both of said plate members about said first hinge line from one of said positions to the other said positions causes said second hinge line to move closer to said third hinge line thereby placing said biasing spring in compression, said compression urging said plate members to one of said positions dependent upon the location of said second hinge line with respect to said first hinge line as said plate members accomplish said pivoting movement.