Abstract: An electromagnetic device includes a stator having a first closed flux carrying path including a core and an air gap opening in the core. Flux is generated in the flux carrying path by a coil, with the direction of flux flow across the air gap being perpendicular to pole surfaces defining the air gap. An armature is mounted to be movable between the pole surfaces and to overlap varying areas of the pole surfaces in dependence upon the position of the armature. The overlap areas are directly proportional to the position of the armature. In one embodiment a bi-directional device having two such closed flux carrying path simultaneously acts on a single armature. The equilibrium position of the armature is dependent on the relative flux flow through the two flux carrying paths. A further embodiment is disclosed in which an air gap opening is inclined to the direction of flux flow in the core of the flux path. The area of each pole surface defining the inclined air gap exceeds the cross-sectional area of the core.

Abstract: A wet plunger solenoid is formed with a three-piece spool assembly including a base and a hub joined by a nonmagnetic sleeve. An electric coil is wound directly onto the sleeve to compress the sleeve about the telescopically interfitted base and hub parts to form a fluid-tight joint, thus forming an armature or plunger cavity which has high resistance to deformation when fluid pressure is applied to the interior. A fluid-tight joint is formed which is free of threaded connections and is reinforced by reason of the fact that the coil is wound in tension, and the cumulative compression effectively joins the parts into a unitary structure.

Abstract: A solenoid includes a base formed with an external taper and an adjacent hub sleeve also formed with an external taper, the base and hub being joined by an alignment piece of non-magnetic material formed with a pair of internal tapers which are proportioned to mate with the external tapers of the hub and the base. The alignment insert assures and maintains a predetermined concentric coaxial alignment of the hub and base with respect to a common movable armature.