Transmission and variable radially expanding spring clutch assembly

Abstract

A transmission generally includes a shaft member having a continuous cylindrical surface portion longitudinally disposed next to a cylindrical outer surface portion interrupted by longitudinal grooves. A first gear assembly has a first clutch spring that holds a first set of rolling members between lobes that extend from a first output gear. A second gear assembly has a second clutch spring that holds a second set of rolling members between lobes that extend from a second output gear. The first gear assembly and the second gear assembly are configured to move longitudinally along the shaft member to a position where at least one of the first gear assembly and the second gear assembly is engaged for rotation with the shaft member when a value of torque at the shaft member is below a torque threshold value.

1 .- 24 . (canceled) 
     
     
         25 . A transmission comprising:
 a shaft member having a continuous cylindrical surface portion longitudinally disposed next to a cylindrical outer surface portion interrupted by longitudinal grooves;   a first gear assembly having a first clutch spring that holds a first set of rolling members between lobes that extend from a first output gear; and   a second gear assembly having a second clutch spring that holds a second set of rolling members between lobes that extend from a second output gear,   wherein said first gear assembly and said second gear assembly are configured to move longitudinally along said shaft member to a position where at least one of said first gear assembly and said second gear assembly is engaged for rotation with said shaft member when a value of torque at said shaft member is below a torque threshold value.   
     
     
         26 . The transmission of  claim 25 , wherein said torque threshold value is at least based on an angle between a surface of one of said longitudinal grooves and a surface of one of said lobes of said first output gear between which said first set of rolling members is disposed such that when a value of said angle decreases, said torque threshold value increases. 
     
     
         27 . The transmission of  claim 25 , wherein said longitudinal grooves define a curvature that varies longitudinally along said shaft member. 
     
     
         28 . The transmission of  claim 25 , wherein said first clutch spring and said second clutch spring have different spring constants. 
     
     
         29 . The transmission of  claim 25 , wherein said first clutch spring includes helical coils that form a helical spring and wherein each of said helical coils contacts a successive coil. 
     
     
         30 . The transmission of  claim 25 , wherein said first clutch spring includes helical coils that form a helical spring and wherein each of said coils is spaced apart from each other. 
     
     
         31 . The transmission of  claim 30 , wherein an end of said first clutch spring is configured to contact a successive coil of said helical coils. 
     
     
         32 . The transmission of  claim 25 , wherein said first clutch spring and said second clutch spring have spring constants that are equal. 
     
     
         33 . The transmission of  claim 25 , wherein said longitudinal grooves are each substantially flat. 
     
     
         34 . The transmission of  claim 25 , wherein a portion of said longitudinal grooves has a curvature that defines at least one of a plane, a v-shape, a radius, a ramp and one or more combinations thereof. 
     
     
         35 . The transmission of  claim 25 , wherein said first clutch spring is an annular unitary sleeve around said rolling members and said lobes of said first output gear. 
     
     
         36 . A transmission comprising:
 a shaft member having a continuous cylindrical surface portion longitudinally disposed next to a cylindrical outer surface portion interrupted by longitudinal grooves; and   a first gear assembly having a first clutch spring that holds a first set of rolling members between lobes that extend from a first output gear,   wherein said first gear assembly is configured to move longitudinally along said shaft member to a position where said first gear assembly is engaged for rotation with said shaft member when a value of torque at said shaft member is below a torque threshold value that is based on an angle between a surface of one of said longitudinal grooves and a surface of one of said lobes between which said first set of rolling members is disposed such that when a value of said angle decreases, said torque threshold value increases.   
     
     
         37 . The transmission of  claim 36  further comprising a second gear assembly having a second clutch spring that holds a second set of rolling members between lobes that extend from a second output gear wherein said first gear assembly and said second gear assembly are configured to move longitudinally along said shaft member to a position where at least one of said first gear assembly and said second gear assembly is engaged for rotation with said shaft member. 
     
     
         38 . The transmission of  claim 36 , wherein said longitudinal grooves define a curvature that varies longitudinally along said shaft member. 
     
     
         39 . The transmission of  claim 37 , wherein said first clutch spring and said second clutch spring have different spring constants. 
     
     
         40 . The transmission of  claim 36 , wherein said first clutch spring includes helical coils that form a helical spring and wherein each of said helical coils contacts a successive coil. 
     
     
         41 . The transmission of  claim 36 , wherein said first clutch spring includes helical coils that form a helical spring and wherein each of said coils is spaced apart from each other. 
     
     
         42 . The transmission of  claim 41 , wherein an end of said first clutch spring is configured to contact a successive coil of said helical coils. 
     
     
         43 . The transmission of  claim 36 , wherein a portion of said longitudinal grooves has a curvature that defines at least one of a plane, a v-shape, a radius, a ramp and one or more combinations thereof.