Lever arch binder mechanism with complementary ring tips

摘要

A ring binder mechanism has D-shaped rings formed by a straight, stationary part, and a movable mating part having an arcuate shape. A recess is formed in the tip of the movable part, and a protrusion at the tip of the stationary part seats in the recess. A lateral window in the recessed tip, intersecting the recess, enables the protrusion to seat smoothly in the recessed tip notwithstanding the fact that the relative motion between the approaching tips has a large lateral component.