Constant displacement dual position cam stop assembly

Abstract

A dual position handle and cam stop assembly is provided which is adapted for limiting rotational movement of an associated valve sealing element such as a ball for a ball valve. However, the assembly is applicable to other types of valves such as butterfly and plug valves. The assembly comprises a cam disc and a valve handle having associated first and second handle stop and direction indicators. The indicators are disposed relative to the cam disc for engagement against the disc at first and second handle stop limit locations, respectively. The locations are selectively positionable by rotation of the cam disc while maintaining a constant relative angular spacing for limiting the rotational movement of the valve handle to the constant relative angular spacing. The cam disc has a cardioid-like contour about its peripheral wall for a constant angular displacement of the stop limit locations per a unit degree of cam rotation. The handle stop and direction indicators preferably comprise a symmetrical flat-faced cam follower.