05301921 is referenced by 126 patents and cites 6 patents.

A rectilinear motion proportional solenoid assembly includes a cylindrical housing containing an electromagnetic coil having a longitudinal coaxial bore. The housing contains magnetic material for providing a flux path for the magnetic field produced by the coil. A generally cylindrical magnetic pole piece element is inserted into the bore and a movable armature assembly of magnetic material is supported within the bore for movement along the longitudinal axis of the coil by a pair of thin, flexible suspension springs. One of the springs is located within the bore adjacent to one end of the magnetic pole piece whereat an axial gap between the pole piece and the armature is formed. A second spring is located within the housing within the vicinity of a radial air gap between the armature and the housing. The pole piece contains an auxiliary region adjacent to the axial air gap for shunting a portion of the axially directed magnetic flux, for effectively causing the force imparted to the movable armature by the application of a current to the electromagnetic coil to be substantially constant irrespective of the magnitude of the axial gap for a variation in the axial gap over a prescribed range.

Title
Proportional electropneumatic solenoid-controlled valve
Application Number
360429
Publication Number
5301921
Application Date
August 31, 1990
Publication Date
April 12, 1994
Inventor
Viraraghavan S Kumar
Palm Bay
FL, US
Agent
Charles E Wands
Assignee
Puritan Bennett
KS, US
IPC
H01F 7/13
F16K 31/06
View Original Source