Electromagnetic synchronizing and shifting clutch

A transmission comprising a rotatable input shaft having a first toothed member and further comprising a rotatable output shaft having a second toothed member, and an electromagnetic clutch selectively operable to couple said first toothed member to said second toothed member and thereby couple said output shaft for rotation in unison with said input shaft, said clutch comprising a rotor associated with said input shaft, an armature associated with said output shaft and normally disposed in axially spaced opposing relation with said rotor, a rotationally stationary field having a coil which is operable when energized to produce magnetic flux for attracting said armature axially toward said rotor, means mounting said rotor to rotate with and to slide axially relative to said input shaft, spring means biasing said rotor axially relative to said input shaft and toward said armature, and a third toothed member rotatable with said armature and disposed in meshing engagement with said second toothed member, energization of said coil attracting said armature axially into frictional engagement with said rotor to cause said armature, said third toothed member, said second toothed member and said output shaft to rotate at substantially the same speed as said input shaft, continued energization of said coil causing said rotor, said armature and said third toothed member to shift axially against the bias of said spring means and thereby bring said third toothed member into engagement with said first toothed member while maintaining said third toothed member in meshing engagement with said second toothed member.

A transmission comprising a rotatable input shaft having a first toothed member and further comprising a rotatable output shaft having a second toothed member, a third toothed member normally disposed in meshing engagement with said second toothed member and normally disposed out of meshing engagement with said first toothed member, and an electromagnetic clutch for first causing said third toothed member to rotate at substantially the same speed as said first toothed member and for thereafter causing said third toothed member to shift axially into meshing engagement with said first toothed member while remaining in meshing engagement with said second toothed member, said clutch comprising a rotor rotatable with and slidable axially along said input shaft, an armature rotatable with said third toothed member and disposed in opposing relation with said rotor, means biasing said rotor axially along said input shaft and toward said armature, means for normally holding said rotor and said armature in axially spaced relation, and coil means which are operable when energized to produce magnetic flux for (a) attracting said armature axially into frictional engagement with said rotor to cause said armature, said third toothed member, said second toothed member and said output shaft to rotate at substantially the same speed as said input shaft, and for (b) thereafter causing said rotor, said armature and said third toothed member to shift axially against the opposition of said biasing means and thereby bring said third toothed member into engagement with said first toothed member while maintaining said third toothed member in meshing engagement with said second toothed member.