Controllable coupling assembly having forward and reverse backlash

Abstract

A controllable or selectable coupling assembly includes a plurality of forward locking elements, at least one reverse locking element and first and second coupling members supported for relative rotation about a common rotational axis. The coupling members include a first, second and third coupling faces. The first coupling face has a set of forward pockets angularly spaced about the axis. The second coupling face has a set of reverse locking formations adapted for abutting engagement with the at least one reverse locking element. The third coupling face opposes the first coupling face and has a set of forward locking formations. Either forward backlash is a non-zero integer multiple of reverse backlash or the reverse backlash is a non-zero integer multiple of the forward backlash to prevent the coupling assembly from inadvertently binding in both directions (i.e. a “lock-lock” condition) about the axis.

1 . A controllable coupling assembly having forward and reverse backlash, the assembly comprising:
 at least one forward locking element having a load-bearing surface;   at least one reverse locking element; and   first and second coupling members supported for relative rotation about a common rotational axis, the coupling members including:
 a first coupling face having a forward pocket to receive each forward locking element and defining a forward load-bearing surface adapted for abutting engagement with the load-bearing surface of its respective forward locking element; 
 a second coupling face having a set of reverse locking formations adapted for abutting engagement with the at least one reverse locking element to prevent the relative rotation in a reverse direction about the axis; and 
 a third coupling face that opposes the first coupling face, the third coupling face having a set of forward locking formations, each of the set of forward locking formations being adapted for abutting engagement with at least one forward locking element to prevent the relative rotation in a forward direction about the axis, wherein either the forward backlash is a non-zero integer multiple of the reverse backlash or the reverse backlash is a non-zero integer multiple of the forward backlash to prevent the coupling assembly from inadvertently binding in both directions about the axis. 
   
     
     
         2 . The assembly as claimed in  claim 1 , further comprising a fourth coupling face that opposes the second coupling face, the fourth coupling face having at least one reverse pocket, each reverse pocket receiving a reverse locking element and defining a reverse load-bearing surface adapted for abutting engagement with a load-bearing surface of its respective reverse locking element. 
     
     
         3 . The assembly as claimed in  claim 1 , wherein the first coupling face has a plurality of forward pockets and wherein the forward pockets are grouped into at least one set and wherein the forward pockets in each set are uniformly angularly spaced. 
     
     
         4 . The assembly as claimed in  claim 3 , wherein the forward pockets are grouped into two or more sets. 
     
     
         5 . The assembly as claimed in  claim 1 , wherein the first coupling member has the first and second coupling faces and the second coupling member has the third coupling face. 
     
     
         6 . The assembly as claimed in  claim 1 , wherein the first coupling face is oriented to face axially in a first direction along the axis, and wherein the second coupling face is oriented to face axially in a second direction opposite the first direction along the axis. 
     
     
         7 . The assembly as claimed in  claim 1 , wherein the forward and reverse locking elements are locking struts. 
     
     
         8 . The assembly as claimed in  claim 1 , wherein the forward and reverse locking formations are notches. 
     
     
         9 . The assembly as claimed in  claim 1 , wherein the first coupling member is a splined ring. 
     
     
         10 . The assembly as claimed in  claim 1 , wherein the first and third coupling faces are annular coupling faces that oppose each other. 
     
     
         11 . The assembly as claimed in  claim 1 , further comprising a plurality of reverse locking elements and a third coupling member having a fourth coupling face that opposes the second coupling face, the fourth coupling face having a set of reverse pockets angularly spaced about the axis, each of the reverse pockets receiving one of the reverse locking elements and defining a reverse load-bearing surface adapted for abutting engagement with a load-bearing surface of its respective reverse locking element. 
     
     
         12 . The assembly as claimed in  claim 11 , wherein the reverse pockets are grouped into at least one set and wherein the reverse pockets in each set are uniformly angularly spaced. 
     
     
         13 . The assembly as claimed in  claim 12 , wherein the reverse pockets are grouped into two or more sets. 
     
     
         14 . The assembly as claimed in  claim 11 , further comprising:
 a control member mounted for controlled, shifting movement between the second and fourth coupling faces relative to the set of reverse pockets and operable for controlling position of the reverse locking elements, the control member allowing at least one of the reverse locking elements to engage at least one of the reverse locking formations in a first position of the control member and wherein the control member maintains the reverse locking elements in their pockets in a second position of the control member.   
     
     
         15 . The assembly as claimed in  claim 14 , wherein the control member comprises a slide plate controllably rotatable about the rotational axis between the first and second positions. 
     
     
         16 . The assembly as claimed in  claim 14 , further comprising a control element coupled to the control member to controllably shift the control member. 
     
     
         17 . The assembly as claimed in  claim 11 , wherein the assembly further comprises:
 a generally round snap ring that is received by an annular groove in the third coupling member to retain the members together and prevent axial movement of the members relative to one another.   
     
     
         18 . A controllable clutch assembly having forward and reverse backlash, the assembly comprising:
 at least one forward locking element having a load-bearing surface;   at least one reverse locking element; and   first and second clutch members supported for relative rotation about a common rotational axis, the clutch members including:
 a first coupling face having a forward pocket to receive each forward locking element and defining a forward load-bearing surface adapted for abutting engagement with the load-bearing surface of its respective forward locking element; 
 a second coupling face having a set of reverse locking formations adapted for abutting engagement with the at least one reverse locking element to prevent the relative rotation in a reverse direction about the axis; and 
 a third coupling face that opposes the first coupling face, the third coupling face having a set of forward locking formations, each of the set of forward locking formations being adapted for abutting engagement with at least one forward locking element to prevent the relative rotation in a forward direction about the axis, wherein either the forward backlash is a non-zero integer multiple of the reverse backlash or the reverse backlash is a non-zero integer multiple of the forward backlash to prevent the coupling assembly from inadvertently binding in both directions about the axis. 
   
     
     
         19 . The assembly as claimed in  claim 18 , wherein the first coupling face has a plurality of forward pockets and wherein forward pockets are grouped into two or more sets. 
     
     
         20 . A controllable coupling assembly having forward and reverse backlash, the assembly comprising:
 at least one forward locking element having a load-bearing surface;   a plurality of reverse locking elements, each of the reverse locking elements having a load-bearing surface; and   first, second and third coupling members supported for relative rotation about a common rotational axis, the coupling members including:
 a first coupling face having at least one forward pocket receiving the at least one forward locking element and defining a forward load-bearing surface adapted for abutting engagement with the load-bearing surface of its respective forward locking element; 
 a second coupling face having a set of reverse locking formations, each of the set of reverse locking formations being adapted for abutting engagement with one of the reverse locking elements to prevent the relative rotation in a reverse direction about the axis; 
 a third coupling face that opposes the first coupling surface, the third coupling face having a set of forward locking formations, each of the set of forward locking formations being adapted for abutting engagement with the at least one forward locking element to prevent the relative rotation in a forward direction about the axis; and 
 a fourth coupling face that opposes the second coupling face, the fourth coupling face having a set of reverse pockets angularly spaced about the axis, each of the reverse pockets receiving one of the reverse locking elements and defining a reverse load-bearing surface adapted for abutting engagement with a load-bearing surface of its respective reverse locking element wherein either the forward backlash is a non-zero integer multiple of the reverse backlash or the reverse backlash is a non-zero integer multiple of the forward backlash to prevent the coupling assembly from inadvertently binding in both directions about the axis. 
   
     
     
         21 . The assembly as claimed in  claim 20 , wherein the reverse pockets are grouped into at least one set and wherein the reverse pockets in each set are uniformly angularly spaced. 
     
     
         22 . A controllable coupling assembly having forward and reverse backlash, the assembly comprising:
 at least one forward and at least one reverse locking element; and   first and second coupling members supported for relative rotation about a common rotational axis, the coupling members including:
 a first coupling rotatable inner ring containing the at least one forward locking member having a biasing member allowing it to engage into an outer member that has locking formations and the at least one reverse locking member contained in the outer member that can be controlled to engage or disengage with locking formations contained on the inner ring, wherein either the forward backlash is a non-zero integer multiple of the reverse backlash or the reverse backlash is a non-zero integer multiple of the forward backlash to prevent the coupling assembly from inadvertently binding in both directions about the axis. 
   
     
     
         23 . A controllable coupling assembly having forward and reverse backlash, the assembly comprising:
 at least one controllable forward and at least one reverse locking element; and   first and second coupling members supported for relative rotation about a common rotational axis, the coupling members including:
 a first coupling rotatable inner ring containing the at least one controllable forward locking member allowing it to engage into an outer member that has locking formations and the at least one reverse locking member contained in the outer member that can be controlled to engage or disengage with locking formations contained on the inner ring, wherein either the forward backlash is a non-zero integer multiple of the reverse backlash or the reverse backlash is a non-zero integer multiple of the forward backlash to prevent the coupling assembly from inadvertently binding in both directions about the axis. 
   
     
     
         24 . A controllable coupling assembly having forward and reverse backlash, the assembly comprising:
 at least one forward and at least one reverse locking element; and   first and second coupling members supported for relative rotation about a common rotational axis, the coupling members including:
 a first coupling rotatable inner ring containing opposing locking formations radially distributed on the outer circumference of the inner ring and an outer member containing at least one each, forward and reverse locking elements radially distributed that can be controlled to engage and disengage with locking formations contained on the inner ring, wherein either the forward backlash is a non-zero integer multiple of the reverse backlash or the reverse backlash is a non-zero integer multiple of the forward backlash to prevent the coupling assembly from inadvertently binding in both directions about the axis. 
   
     
     
         25 . A controllable coupling assembly having forward and reverse backlash, the assembly comprising:
 at least one forward and at least one reverse locking element; and   first and second coupling members supported for relative rotation about a common rotational axis, the coupling members including;
 a first coupling rotatable inner ring containing opposing locking formations radially distributed on the outer circumference of the inner ring and an outer member containing at least one each, forward and reverse locking elements radially distributed, one of which can be controlled to engage or disengage with locking formations contained on the inner ring and the other locking element having a biasing member allowing it to engage into the outer member in the forward direction, wherein either the forward backlash is a non-zero integer multiple of the reverse backlash or the reverse backlash is a non-zero integer multiple of the forward backlash to prevent the coupling assembly from inadvertently binding in both directions about the axis