Safety lock loose-leaf ring binder mechanism

Claim 1

In a loose-leaf binding mechanism whcih includes an elongated spring case, a pair of relatively stiff but resilient elongated hinge plates pivotally mounted within the case, the outer longitudinal edge of each plate defining its pivot axis with the inner longitudinal edges of the plate disposed in abutting relationship for all angular positions of the hinge plates, at least one prong on each hinge plate projecting externally of the case with each prong on one hinge plate being positioned in alignment with a prong on the other hinge plate, and actuator means for moving said hinge plates between a prong-closed position wherein each pair of aligned prongs form a substantially closed loop for retaining loose-leaf sheets and a prong-open position wherein each pair of aligned prongs are spread apart to permit insertion and removal of loose-leaf sheets, the improvement wherein the actuator means comprises: a. a pivotally mounted lever member positioned in an opening in the hinge plates and pivotally-operated around the opening in the hinge plates; b. hinge plate depressor means carried on said lever member for moving the hinge plates from said prong-open position to said prong-closed position upon pivoting of the lever member in one direction through a first predetermined arcuate segment of the path of movement of the lever member; c. plate lifting means carried on said lever member for moving the hinge plates from said prong-closed position to said prongopen position upon pivoting of the lever member in the opposite direction through said first arcuate segment; d. one poRtion of said lever member which portion includes lug elements being selectively movable along a second predetermined arcuate segment of the path of movement of the lever member between a first position where it is wedged tightly between the case and prong-closed hinge plates such that an imaginary line interconnecting any point of contact between said one portion and the case with any point of contact between said one portion and the hinge plates is oriented at an upwardly inclined outwardly extending attitude and a second position where it is wedged tightly between the case and prong-closed hinge plates such that said imaginary line is oriented at an upwardly inclined inwardly extending attitude, said second predetermined arcuate segment being adjacent to the said first arcuate segment and further being on the inward side of said first segment; e. lock stop means capable of preventing pivotal movement of the lever member inwardly out of wedged-in engagement between the case and outwardly bowed hinge plates, said stop means including: i. a stationary seating surface mounted on the case in the path of movement of said lever member which surface is along the centerline of the case and a substantial distance to either side of the centerline; and ii. a retaining element mounted on said lever member for engagement along the centerline of the case and for engagement a substantial distance to either side thereof with said seating surface upon movement of said one portion of the lever member into said second wedged-in position; and f. said case being transversely arched with the crown of the arch facing up and said one portion of the lever member including a transversely arched body conforming generally to the curvature of the case with its crown extending generally inwardly or upwardly depending on the angular position of the lever member, said body having a lower surface and a transversely arched upper surface conforming generally to the curvature of the case, said lug elements depending downwardly from the lower surface with one lug element positioned on one side of center and another lug element positioned on the other side of center with each lug element extending into engagement with one of said hinge plates, said upper surface engaging the case and the terminal ends of said lugs engaging the respective hinge plates at all wedged-in angular positions of said one portion of the lever member.