Sprag assembly for one-way clutches

Abstract

An overrunning clutch is disclosed herein providing a structure whereby a drive and driven member are interconnected to provide a drive condition therebetween in one direction, of relative rotation thereof and an overrunning condition therebetween in the other direction of relative rotation thereof. A sprag assembly is shown in conjunction with the overrunning clutch and possesses a structure which provides for total disengagement of the sprags from the overrun portion of the clutch during the overrunning thereof.

I claim: 
     
       1. A sprag assembly for one-way overrunning clutches having an inner and an outer race comprising a sprag cage for retaining sprags between the inner and the outer races, a series of sprags rotatably mounted in said cage and about axis fixed with respect to the cage, said sprags having inner and outer race cam surfaces normally engaging the inner and outer races respectively when rotated in one direction to provide a drive between said races and tending to disengage and drag on adjacent races in the other direction to provide a nondriving overrunning condition between said races, .Iadd.friction drag means between said cage and one of said races, .Iaddend.and means in engagement with said sprags for urging said sprags rotatably in said one direction, said sprags having a counterweight portion for rotatably urging said sprags in the other direction under the effects of centrifugal force when said cage is rotated in overrunning condition with .Iadd.said .Iaddend.one of said races for overcoming the effects of said sprag engaging and urging means at a predetermined rotational speed to cause said sprags to completely disengage from said races during overrunning above said predetermined speed. 
     
     
       2. A sprag assembly as recited in claim 1, wherein said sprags have trunnions supported by said cage, the longitudinal centers thereof defining said axes and the centers of rotation of said sprags. 
     
     
       3. A sprag assembly as defined in claim 2 whereby said sprag cam surfaces (31) adjacent said inner race have a center of curvature spaced outwardly from the center of rotation of said sprags. 
     
     
       4. A sprag assembly as defined in claim 2 wherein said sprag outer cam surfaces have a center of curvature spaced inwardly from the center of rotation of said sprags. 
     
     
       5. A sprag assembly as defined in claim 2, wherein said sprags are provided with a transverse surface spaced radially outwardly from the center of rotation thereof, and said means for rotatably urging said sprags in the one direction is a resilient radially expanding means in engagement with said transverse surface. 
     
     
       6. A sprag assembly as defined in claim 5 wherein .[.a.]. .Iadd.said friction drag .Iaddend.means is provided for yieldably urging said cage to rotate with an overrunning race to impart rotation to said cage and effect said sprag centrifugal rotation. 
     
     
       7. A sprag assembly as defined in claim 2 wherein .[.a.]. .Iadd.said friction drag .Iaddend.means is provided for yieldably urging said cage to rotate with an overrunning race to impart rotation to said cage and effect said sprag, centrifugal rotation. 
     
     
       8. A sprag assembly as defined in claim 7 wherein said yieldably urging means is a resilient member secured to said cage and is spring biased into frictional engagement with said overrunning race. 
     
     
       9. A sprag assembly as defined in claim 8 whereby said sprag cam surface (31) adjacent said inner race have a center of curvature speed outwardly from the center of rotation of said sprags. 
     
     
       10. A sprag assembly as defined in claim 8 wherein said sprag outer cam surfaces have a center of curvature spaced inwardly from the center of rotation of said sprags.