Cam and roller overcenter handle mechanism

摘要

An overcenter mechanism (10) includes a housing (12) and a first shaft (14) mounted on the housing. The first shaft has a first axis (34). A second shaft (20) is mounted on the housing and the second shaft has a second axis (41) that parallels the first axis. A lever (16) is attached to the first shaft, and the lever pivots about the first axis in response to a force (F op ) applied to the lever. A cam (18) is attached to the first shaft, and the cam pivots about the first axis. The cam has a cam surface including a first surface portion (58) and a second surface portion (60). The first and second surface portions form a cusp (62) therebetween. A cam follower (21) has a cam follower surface, and the cam follower pivots about the second axis. A biasing member (26) urges the cam follower surface against the cam surface in pressure contact. The cam follower and the pressure contact cooperate with the cam to generate torque (Ä roller ) on the cam until the cam follower surface contacts the cusp. The pressure contact creates an instability about the cusp when the cusp contacts the cam follower surface, and the torque pivots the cam so the cusp and the cam follower move away from each other.