Self-adjusting electromagnetic clutch-brake

Claim 2

An electromagnetic friction device for torque transmission comprising: input means; output means; torque transmitting means for transferring torque from said input means to said output means, said torque transmitting 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; electromagnetic means for actuating said friction device, said means producing an axial engaging force for attracting said armature when energized; and means for braking said output means when said electromagnetic means is de-energized, said braking means being operatively integral with said torque transmitting means.

Claim 3

An electromagnetic clutch apparatus for torque transmission comprising: an input shaft; driving means rotatably mounted in axially fixed position to said input shaft, said driving 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 driving means, said actuating means including an electromagnetic winding; output means; an armature drivenly connected to said output means, said armature being axially movable along said input shaft toward and away from said pole face of said driving means in response to said clutch actuating means, said armature having an outer cylindrical threaded surface; a driven 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 driving means; a resilient torque transmitting member rotatively connecting said driven friction member to said output means, said member adapted to flex axially upon energization and de-energization of said actuating means; and means for braking said output means when said actuating means is de-energized, said braking means being operatively integral with said resilient torque transmitting member; 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 armature, said armature being threadably related to said driven friction member such that upon engagement of said armature and said pole face said driven friction member advances on said threads of said armature thereby engaging the mating frustro-conical friction surface of said driving member until nearly all the torque transmitted between the input and output is carried by said mating frictional surfaces.

Claim 4

An electromagnetic clutch apparatus for torque transmission comprising: an input shaft; driving means rotatably mounted in axially fixed position to said input shaft, said driving 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 driving means, said actuating means including an electromagnetic winding; output means; an armature drivenly connected to said output means, said armature being axially movable along said input shaft toward and away from said pole face of said driving means in response to said clutch actuating means, said armature having an outer cylindrical threaded surface; a driven 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 driving means; a resilient torque transmitting member rotatively connecting said driven friction member to said output means, said member adapted to flex axially upon energization and de-energization of said actuating means; and means for braking said output means when said actuating means is de-energized, said braking means being operatively integral with said resilient torque transmitting member; 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 armature, said armature being threadably related to said driven friction member such that upon engagement of said armature and said pole face said driven friction member advances on said threads of said armature thereby engaging the mating frustro-conical friction surface of said driving member until nearly all the torque transmitted between the 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; resilient torque transmitting means fixedly interconnecting said friction member to said output means for imparting rotational motion to said output means; and means for braking said output means when said electromagnetic coil means is de-energized, said braking means being operatively integral with said resilient torque transmitting means 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; resilient torque transmitting means fixedly interconnecting said friction member to said output means for imparting rotational motion to said output means; and means for braking said output means when said electromagnetic coil means is de-energized, said braking means being operatively integral with said resilient torque transmitting means 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 recited 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.

Claim 9

The combination as claimed in claim 3 wherein said means for braking said output means comprises an annular friction brake member mounted to said nonmagnetic friction member and operative to apply a braking action to said output means under the influence of said resilient torque transmitting member; and a rotatively fixed frame member for reacting against said brake member when said brake member is biased into contact with said frame member upon de-energization of said coil means.