Patent ID: 7871060

Claim:
A solenoid actuator, comprising: an electromagnetic coil defining an aperture therethrough; a non-ferromagnetic coil tube having a first end and a second end, at least a portion of said coil tube disposed within said aperture of said electromagnetic coil, said coil tube comprising a substantially annular tube having a first end, a second end, a first portion and a second portion, said first portion of said coil tube having a first inside diameter and said second portion of said coil tube having a second inside diameter smaller than said first inside diameter; a ferromagnetic coil tube end closure, said coil tube end closure substantially closing said first end of said coil tube; a top plate defining an aperture, at least a portion of said coil tube disposed within said aperture; a top compression plate defining an aperture, at least a portion of said coil tube disposed within said aperture; a top seal member engaged with said top plate, said top compression plate, and said coil tube; and a ferromagnetic armature comprising a generally cylindrical structure having a first end, a second end, a first portion having a diameter generally corresponding to said inside diameter of said first portion of said coil tube, and a second portion having a diameter generally corresponding to said inside diameter of said second portion of said coil tube; wherein said first portion of said armature is in sliding engagement with said first portion of said coil tube and said second portion of said armature is free to slide through said second portion of said coil tube; wherein said coil tube end closure prevents said armature from escaping from said coil tube through said first end of said coil tube; and wherein said second portion of said coil tube prevents said first portion of said armature from escaping from said coil tube through said second end of said coil tube.