Patent ID: 9620274
Date: 2017-04-11
CPC Classifications: F16K,H01F

Claim:
1. An apparatus comprising: a ferromagnetic housing defining a housing cavity, the cavity having an exterior surface with a first portion of a mechanically engageable structure on a portion of the exterior surface; an electrically-conductive coil disposed in the housing cavity and defining a coil cavity; a ferromagnetic core piece disposed in the coil cavity; a ferromagnetic pole piece comprising a first face in contact with the core piece and a projection extending from a second face of the pole piece opposite the first face; a flexible element defining an opening, where the projection is disposed within the opening and the flexible element is disposed between a portion of the projection and the first face of the pole piece; a ferromagnetic armature coupled to the flexible element, where the flexible element is disposed between at least a portion of the armature and the first face of the pole piece; the ferromagnetic armature including a guide spring attached to a back face of the ferromagnetic armature, and a second spring within the ferromagnetic armature; a body housing having a second portion of the mechanically engageable structure on an interior portion of the housing; the first portion of the mechanically engageable structure operatively coupled with the second portion of the mechanically engageable structure to create an adjustable preload tension on the guide spring and the second spring; and the adjustable preload tension selectively operable to modify an amount of coil current required to initiate motion in the armature.