Patent ID: 6918571

Claim:
A solenoid operated valve assembly comprising: (a) a valve body with a moveable valve member disposed therein and a first annular flux collector attached to the body with a first bearing surface and an electrical coil having one end thereof proximate said first flux collector; (b) an armature disposed within the coil with an operating rod disposed for movement therewith, the rod having an end thereof guided by said bearing surface and contacting said valve member; (c) a second annular flux collector disposed at an end of the coil remote from said first flux collector and with one axial end of said second flux collector defining a working air gap with the armature and with an end of said rod distal said first end extending within said second flux collector; (d) an adjustment member with a second bearing surface disposed on said second flux collector with an end of said rod distal said one end guided for movement in said second bearing surface; and, (e) a spring disposed about the rod and having one end registered against said adjustment member and an end opposite said one end registered against said armature for biasing said armature in one direction, wherein said adjustment member is rotatable on said second flux collector for varying the preload on said spring.