Electromagnetic positioner for a servovalve or the like

Abstract

An electromagnetic positioner for positioning the drive arm of a servovalve or the like, comprising an armature extending between laterally spaced pairs of vertically disposed and vertically spaced coils for pivotal movement in a plane which includes the axes of said coils, a drive arm assembly comprising a flexure tube secured to the base or lower pole of the positioner, and extending upwardly to a position above the level of the armature, and an adapter secured at its lower end to the armature and its upper end to the upper ends of the flexure tube and drive arm so that the pivot point of the armature is adjacent but above the center of rotation of the drive arm. Also provided is a null adjusting arrangement in which the driven parts are located partly in the body of the positioner and partly in the body of the pilot valve, thereby freeing space in the positioner and reducing the height thereof. Means are provided to prevent escape from the positioner body of components of the null adjusting mechanism prior to assembly of the positioner and the related pilot valve assembly. Permanent magnets are entrapped and prevented from moving substantial distances within the positioner by studs which also secure parts of the positioner assembly and by the cover for the positioner.