Patent ID: 7293932
Filing Date: 2007-11-13
Classification: B42F

Abstract:
1. In a ring binder mechanism comprising a base plate supporting a plurality of rings, each ring comprising a stationary part and a movable part, and a crank for moving the movable part of each ring so that the rings can be opened and closed, the improvement wherein one of the parts substantially arcuate, terminating at a first tip, and the other of said parts is straight, terminating at a second tip, so that the tips approach one another in a direction substantially oblique to the length of the straight part as the rings are closed, one of said tips has a protrusion and the other of said tips has a complementary recess for receiving the protrusion when the rings are closed, and the tip with the complementary recess also has a lateral window intersecting the recess from only one side, the window being situated and shaped to permit the protrusion to enter the recess in said direction substantially oblique to the length of the straight part but to prevent it from moving in other directions with respect to the recess once seated in the recess.