Two speed magnetic clutch drive

Claim 1

A double magnetic friction coupling having, in combination, armature disks axially fixed and spaced apart along a common axis, means supporting at least one of said disks for rotation about said axis, an axially fixed hub rotatable about said axis, a magnet unit surrounding and concentric with said hub and comprising two back-to-back magnets of U-shaped cross-section rigid with each other and having concentric pole pieces with ends facing axially in opposite directions and separated from the opposed armature disks by narrow air gaps when the magnets are in a centered position, each of said magnets having a multiple turn winding disposed between the pole pieces thereof cooperating with the opposed armature to define a toroidal path for flux causing attraction of the magnet to and gripping engagement with such disk when the winding of the magnet is energized, and generally flat spring means joining said hub and said magnet unit and providing therebetween a torque transmitting connection which is free of rubbing friction and supports said magnet unit for free axial floating relative to said hub from said centered position in opposite directions into engagement with said armature disks undeR the attractive force of the respective magnets, said spring means being substantially unstressed when free with the magnet unit in said centered position but oppositely stressed in the attraction of said unit to and against the respective armature disks whereby to develop in each instance an axially directed force for returning said unit to said centered position when the magnet producing the attraction is deenergized.