Proportional and latching pressure control device

Claim 1

A proportional pressure control device, comprising: a motor having a housing and a reciprocally movable armature therein movable between first and second limits; a valve body secured to said housing; a plate-like poppet valve member on at least one end of said armature, said plate-like poppet valve member having a flat surface thereon oriented in a plane that extends perpendicular to the direction of movement of said armature and on a side thereof remote from said one end of said armature; means defining a fluid pressure port in said valve body adapted to be connected to a fluid pressure source, said pressure port extending into the interior of said valve body to further means defining a chamber; wherein a flow restrictor means is provided in said pressure port to restrict fluid flow from a pressure source into said pressure port and said chamber; nozzle outlet means in said chamber having an annular flat valve seat thereon directly opposing said plate-like poppet valve member, the spacing between said valve seat and said valve member controlling the magnitude of the fluid pressure in said chamber; means for preventing a magnetic holding of said armature at said first limit position; means for effecting a movement of said armature in a manner that is substantially proportionally related to a variable current signal between a position of said armature at said first limit position and a position of said one side of said plate-like poppet valve member whereat it engages said flat valve seat; magnetic latching means for releasably magnetically holding said armature in at least said second limit position, said plate-like poppet valve member engaging said valve seat and restricting fluid flow out of said nozzle outlet means when said armature is magnetically held in said second limit position as well as oriented a finite distance away from said second limit position whereat said armature is free of said magnetic latching means and said poppet valve member engages said valve seat; and compensating means coupled between said plate-like poppet valve member and said armature for compensating for a continued movement of said armature from said finite distance away from said second limit position toward said second limit position following an engagement of said plate-like poppet valve member with said valve seat.