Patent ID: 8678343

Claim:
A solenoid device comprising: a stator assembly comprising: a stator having a generally cylindrical magnetic housing of generally U-shaped cross-section including an open end in communication with a hollow, interior portion, and a flux ring, defining a magnetic pole, coupled to the opened end, the flux ring having an opening there-through, a coil associated with the stator and constructed and arranged to be energized to generate a magnetic field, an armature having a generally ring-shaped base of a constant, first diameter and a generally rod-shaped stem portion of a constant, second diameter extending transversely from the base such that the base and stem portion define a generally T-shaped cross-section with the first diameter being substantially greater than the second diameter, the base being able to be received in the opening of the flux ring with the stem portion extending into the interior portion, the armature being constructed and arranged to move with respect to the stator assembly between a closed position and an open position in response to the generated magnetic field, and a spring biasing the armature to the closed position, wherein the stem portion of the armature includes a bore, the spring being disposed in the bore, wherein the stator and armature are constructed and arranged such that a force on the armature decreases as a portion of the armature moves further into the interior portion of the housing of the stator, towards the open position thereof.