Patent ID: 8665046

Claim:
An electromagnetic coil assembly comprising: a magnetically susceptible pole piece having a channel structure and a first flange member, the channel structure having an annular inner side wall, an annular outer side wall and an annular end wall that fixedly couples the inner and outer side walls to one another on a first axial end of the pole piece, the channel structure being open on a second axial end of the pole piece that is opposite the first axial end, the first flange member being coupled to an end of one of the inner and outer side walls on the second axial end, the first flange member (i) extending in a radial direction of the pole piece towards an interior of the channel structure, and (ii) defining a first contact surface; a coil assembly fixedly coupled to the channel structure between the inner and outer side walls; and an armature plate defining a second contact surface, the first contact surface being in contact with the second contact surface in a first configuration when the coil assembly is energized so as to inhibit relative motion between the pole piece and armature plate, the first contact surface being separated from the second contact surface by a gap in a second configuration when the coil assembly is de-energized so as to allow relative motion between the pole piece and armature plate.