Self-adjusting electromagnetic clutch

Claim 2

An electromagnetic friction device for torque transmission comprising: input means; output means; driving means for transferring torque from said input means to said output means, said driving means including a cone shaped friction ring member, said member having a helical thread along its inner diameter; an annular ferro-magnetic armature, said armature being threadably received in the helical thread of said cone member for relative rotation therewith, the threaded connection of said cone member and said armature being such that said cone member is adapted to advance on its thread into axial engagement with the output means; and electromagnetic means for actuating said friction device, said means producing a circuitous flux path through said armature when energized.

Claim 3

An electromagnetic clutch apparatus for torque transmission comprising: an input shaft; output means mounted in axially fixed position on said input shaft and free to rotate thereon, said output means having a frustro-conical friction face tapering radially inward and a flat annular pole face disposed normally to the axis of said input shaft; clutch actuating means mounted adjacent to said output means, said actuating means including an electromagnetic winding; an armature drivingly connected to said input shaft, said armature being axially movable along said input shaft toward and away from said pole face of said output means in response to said clutch actuating means, said armature having an outer cylindrical threaded surface; a driving friction member having an inner cylindrical threaded surface adapted To threadably engage the outer surface of said armature, said friction member having a frustro-conical face for frictionally engaging the frustro-conical face of said output means; and a resilient torque transmitting member rotatably connecting said driving member to said input shaft, said member adapted to flex axially upon energization and de-energization of said actuating means; whereby said actuating means produces a circuitous flux path when energized which flux path passes through said pole face and said armature, moving said armature into contactive engagement with said pole face thereby imparting rotational momentum to said output means, said armature being threadably related to said driving friction member such that upon engagement of said armature and said output means said driving member advances on said threads of said armature thereby engaging the mating frustro-conical friction surface of said driving member and said output means until nearly all the torque transmitted between input and output is carried by said mating frictional surfaces.

Claim 4

An electromagnetic clutch apparatus for torque transmission comprising: an input shaft; output means mounted in axially fixed position on said input shaft and free to rotate thereon, said output means having a frustro-conical friction face tapering radially inward and a flat annular pole face disposed normally to the axis of said input shaft; clutch actuating means mounted adjacent to said output means, said actuating means including an electromagnetic winding; an armature drivingly connected to said input shaft, said armature being axially movable along said input shaft toward and away from said pole face of said output means in response to said clutch actuating means, said armature having an outer cylindrical threaded surface; a driving friction member having an inner cylindrical threaded surface adapted To threadably engage the outer surface of said armature, said friction member having a frustro-conical face for frictionally engaging the frustro-conical face of said output means; and a resilient torque transmitting member rotatably connecting said driving member to said input shaft, said member adapted to flex axially upon energization and de-energization of said actuating means; whereby said actuating means produces a circuitous flux path when energized which flux path passes through said pole face and said armature, moving said armature into contactive engagement with said pole face thereby imparting rotational momentum to said output means, said armature being threadably related to said driving friction member such that upon engagement of said armature and said output means said driving member advances on said threads of said armature thereby engaging the mating frustro-conical friction surface of said driving member and said output means until nearly all the torque transmitted between input and output is carried by said mating frictional surfaces.

Claim 5

In combination with an electromagnetic clutch of the type wherein torque is transmitted from an input means to an output means upon energization of an electromagnetic coil means and wherein the armature is disposed normally to the clutch axis for engagement with a magnetic pole face, the improvement which comprises: an annular frustro-conically shaped nonmagnetic friction member advanceably threaded to said armature for driving said output means when said electromagnetic coil means is energized; and resilient torque transmitting means fixedly interconnecting said friction member to said input means for imparting rotational motion to said friction member whereby the electromagnetic engaging force is axial through said armature, and the primary torque transferring surface is the frustro-conical surface of said friction member, therefore maintaining close contact between said armature and said pole face while simultaneously allowing said friction member to self-adjust for wear.

Claim 6

In combination with an electromagnetic clutch of the type wherein torque is transmitted from an input means to an output means upon energization of an electromagnetic coil means and wherein the armature is disposed normally to the clutch axis for engagement with a magnetic pole face, the improvement which comprises: an annular frustro-conically shaped nonmagnetic friction member advanceably threaded to said armature for driving said output means when said electromagnetic coil means is energized; and resilient torque transmitting means fixedly interconnecting said friction member to said input means for imparting rotational motion to said friction member whereby the electromagnetic engaging force is axial through said armature, and the primary torque transferring surface is the frustro-conical surface of said friction member, therefore maintaining close contact between said armature and said pole face while simultaneously allowing said friction member to self-adjust for wear.

Claim 7

The combination as claimed in claim 3 including further means for retarding said friction member from reversing its direction of rotation relative to said armature.

Claim 8

The combination as claimed in claim 3 wherein said friction member is composed of an organic friction material.