Toggle clamp having a lock mechanism engageable as an over-center position is approached

Claim 1

A CLAMPING DEVICE COMPRISING A PAIR OF WORK ENGAGING JAWS, A JAW PIVOT INTERCONNECTING SAID JAWS, A CLAMP OPENING SPRING INTERCONNECTING SAID JAWS, A PAIR OF HANDLES HAVING TOGGLE LINK PINS SECURED THERETO, A TOGGLE JOINT PIVOTALLY INTERCONNECTING SAID HANDLES BETWEEN THE LINK PINS, ONE OF SAID JAWS BEING PIVOTALLY CONNECTED TO ONE OF THE HANDLES BY THE LINK PIN THEREON, A RIGID LINK MEMBER PIVOTALLY CONNECTED BETWEEN THE LINK PIN OF THE OTHER OF SAID HANDLES AND THE JAW PIVOT, YIELDABLE LINK MEANS INTERCONNECTED BETWEEN THE OTHER OF SAID JAWS AND SAID ONE OF THE HANDLES FOR RESISTING DISPLACEMENT OF THE TOGGLE JOINT TOWARD AN OVER-CENTER POSITION BETWEEN THE LINK PINS AFTER THE JAWS ENGAGE A WORKPIECE, CLAMP REGULATING LOCK MEANS MOUNTED ON THE LINK MEMBER FOR RIGID INTERCONNECTION THEREOF TO THE OTHER OF SAID JAWS AFTER ENGAGEMENT OF THE WORKPIECE AND CLAMP ADJUSTING RELEASE MEANS MOUNTED ON LINK MEMBER AND THE OTHER OF SAID HANDLES FOR HOLDING THE LOCK MEANS DISENGAGED UNTIL THE TOGGLE JOINT APPROACHES SAID OVER-CENTER POSITION.