Electromagnetic assembly

Claim 1

An electromagnetic apparatus comprising: (a) an axially elongated metallic ferromagnetic core having (i) inner and outer axially extending walls radially spaced from each other to thereby define a cavity for enclosing a coil assembly, (ii) an annular opening in the core between the walls at one axial end thereof in order to permit the insertion or removal of a coil assembly. (iii) an annular closure between the walls at the other axial end thereof defining the axial limit of the coil assembly cavity, (iv) an axial bore extending radial outward from the longitudinal axis of the core to the inner wall, open at both ends of the core and adapted to accommodate a reciprocating armature. (b) a coil assembly adapted to fit in the core cavity and including (i) a cylindrical body, (ii) radial flanges on each end of the cylindrical body and sized to easily pass axially into the annular opening and between the walls of the core and into the core cavity, (iii) a coil of wire wound around the cylindrical body between the flanges thereof, and (iv) interference means carried by the coil assembly extending radially beyond the flanges and positioned abutting against at least one core wall in order to primarily support and removably hold the coil assembly in the core cavity between the walls thereof.