Locking mechanism for an adjustable spindle drive

摘要

A valve spindle drive is disclosed in which the travel of the spindle is limited by a locking mechanism. The spindle is driven by a gearing system on which locking rings are provided. Each locking ring permits rotation in one direction. Arms resiliently mounted on the valve housing carry a second pair of locking rings for mating with the rings on the gearing system. Deflection of the arms during travel of the spindle actuates switches for controlling a spindle motor drive. Movement of the spindle and gearing relative to the second pair of locking elements provides for engagement of a pair of respective locking rings to prevent further spindle travel. The other pair of rings is prevented from coupling by a cam device carried by the gearing.