Patent ID: 6392516
Filing Date: 2002-05-21
Classification: H01F

Abstract:
A latching solenoid comprising:a pole member of a magnetic material, said pole member including a pole face; an armature of a magnetic material, said armature including an armature end portion having an armature face opposing said pole face, said armature being supported for movement relative to said pole face between first and second positions, said armature face being spaced apart from said pole face defining an air gap between said armature face and said pole face when said armature is in said first position; a coil assembly for producing magnetic flux along a magnetic flux path for moving said armature from said first position to said second position, said armature being maintained in said second position by the effects of a magnetic force; and a magnetic flux shunt member of a magnetically permeable material carried by said armature, said magnetic shunt member being located adjacent to said pole face, said magnetic shunt member being configured and arranged to shunt at least a portion of the air gap between said armature face and said pole face when said armature is in said first position to provide a low reluctance magnetic flux path between said pole member and said armature, wherein said magnetic shunt member is of a material that is different from the material of said armature, and wherein the coil assembly includes a step-wound coil, the step-wound coil including a first winding portion having a first inner diameter, and a second winding portion having a second inner diameter which is larger than the first inner diameter and which is larger than an outer diameter of said armature end portion, defining a region of increased diameter receiving at least a portion of said magnetic flux shunt member, allowing at least said portion of said magnetic flux shunt structure to overlap said end portion of said pole piece when said armature is at said second position member to overlap said end portion of said pole piece when said armature is at said second position.