Abstract:
An insert, a motion-transmitting mechanism and a method of operating a motion-transmitting mechanism. The insert may include an insert body receivable in a bore, the insert body having an outer surface at least partially engageable in a driving relationship with a bore surface, the insert body defining an insert bore operable to receive a shaft in a driving relationship, torque transmission between the shaft and the motion-transmitting member through the insert body causing a portion of the insert body to compress toward the shaft.

Description:
RELATED APPLICATION 
       [0001]    This application claims priority to co-pending, prior-filed U.S. Provisional Patent Application No. 62/279,307, filed Jan. 15, 2016, the entire contents of which are incorporated by reference. 
     
    
     FIELD 
       [0002]    This invention generally relates to a coupling for removable axial locking of a hub on a rotating power transmission shaft. 
       SUMMARY 
       [0003]    In one independent aspect, an insert for a motion-transmitting mechanism may be provided. The motion-transmitting mechanism may include a member defining a bore with a bore surface, and a shaft. The insert may generally include an insert body receivable in the bore, the insert body having an outer surface at least partially engageable in a driving relationship with the bore surface, the insert body defining an insert bore operable to receive the shaft in a driving relationship, torque transmission between the shaft and the motion-transmitting member through the insert body causing a portion of the insert body to compress toward the shaft. 
         [0004]    In another independent aspect, a motion-transmitting mechanism may generally include a motion-transmitting member defining a bore with a bore surface; a shaft; and an insert including an insert body receivable in the bore, the insert body having an outer surface and defining an insert bore operable to receive the shaft, engagement between the bore surface and the outer surface providing torque transmission between the insert and the motion-transmitting member and causing a portion of the insert body to compress toward the shaft. 
         [0005]    In yet another independent aspect, a method of operating a motion-transmitting mechanism may be provided. The motion-transmitting mechanism may include a motion-transmitting member defining a bore with a bore surface, a shaft, and an insert, the insert having an insert body received in the bore, the insert body having an outer surface and defining an insert bore for receiving the shaft. The method may generally include transmitting torque between the shaft and the motion-transmitting member, transmitting including engaging the bore surface and the outer surface to transmit torque between the insert and the motion-transmitting member; and by torque transmitted between the insert and the motion-transmitting member, causing a portion of the insert body to compress toward the shaft. 
         [0006]    In a further independent aspect, an insert for a yoke assembly may be provided. The assembly may include a yoke, and a hub connected to the yoke, the hub defining a bore with a bore surface. The insert may generally include an insert body receivable in the bore, the insert body having an outer surface at least partially engageable in a driving relationship with the bore surface, the insert body defining an insert bore operable to receive a shaft in a driving relationship, torque transmission between the shaft and the motion-transmitting member through the insert body causing a portion of the insert body to compress toward the shaft. 
         [0007]    In another independent aspect, a yoke assembly may generally include a yoke; a hub connected to the yoke, the hub defining a bore with a bore surface; and an insert including an insert body receivable in the bore, the insert body having an outer surface at least partially engageable in a driving relationship with the bore surface, the insert body defining an insert bore operable to receive a shaft in a driving relationship, torque transmission between the shaft and the motion-transmitting member through the insert body causing a portion of the insert body to compress toward the shaft. 
         [0008]    In a yet another independent aspect, a method of operating a yoke assembly may be provided. The assembly may include a yoke, a hub connected to the yoke, the hub defining a bore with a bore surface, and an insert including an insert body received in the bore, the insert body having an outer surface and defining an insert bore for receiving a shaft. The method may generally include transmitting torque between the shaft and the hub, transmitting including engaging the bore surface and the outer surface to transmit torque between the insert and the hub; and, by torque transmitted between the insert and the hub, causing a portion of the insert body to compress toward the shaft. 
         [0009]    In a further independent aspect, a method of manufacturing an insert for a motion-transmitting mechanism may be provided. The motion-transmitting mechanism may include a motion-transmitting member defining a bore with a bore surface, and a shaft. The method may generally include providing bar stock having a polygonal outer surface, when the insert is formed, the outer surface being at least partially engageable in a driving relationship in the bore; cutting the bar stock to a length for the insert; forming an insert bore in the insert for receiving the shaft in a driving relationship, forming including providing a side wall having adjacent wall sections; and forming a slot in at least one wall section to accommodate compression of the insert, in operation, torque transmission between the shaft and the motion-transmitting member through the insert causing a portion of the insert to compress toward the shaft. 
         [0010]    Other independent features and independent aspects of the invention will become apparent by consideration of the following detailed description, claims and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a front perspective view of a collet locking yoke. 
           [0012]      FIG. 2  is another front perspective view of the yoke of  FIG. 1  with the insert retaining ring removed. 
           [0013]      FIG. 3  is a front perspective view of the yoke of  FIG. 1  with the insert removed. 
           [0014]      FIG. 4  is a rear perspective view of the yoke of  FIG. 1 . 
           [0015]      FIG. 5  is an exploded view of the yoke of  FIG. 1 . 
           [0016]      FIG. 6  is a partially exploded view of the yoke of  FIG. 1 . 
           [0017]      FIG. 7  is a front perspective view of the yoke of  FIG. 1  with the insert and the retaining ring removed. 
           [0018]      FIG. 8  is a front view of the yoke of  FIG. 1 . 
           [0019]      FIG. 9  is a front view of the yoke of  FIG. 1  with the retaining ring removed. 
           [0020]      FIG. 10  is a front view of the yoke of  FIG. 1  with the insert removed. 
           [0021]      FIG. 11  is a rear view of the yoke of  FIG. 1 . 
           [0022]      FIG. 12  is a top view of the yoke of  FIG. 1 . 
           [0023]      FIG. 13  is a bottom view of the yoke of  FIG. 1 . 
           [0024]      FIG. 14  is a side view of the yoke of  FIG. 1 . 
           [0025]      FIG. 15  is an opposite side view of the yoke of  FIG. 1 . 
           [0026]      FIG. 16  is a cross-sectional view of the yoke of  FIG. 1 , taken generally in a vertical plane through the axis. 
           [0027]      FIG. 17  is a cross-sectional view of the yoke of  FIG. 1 , taken generally in a horizontal plane through the axis. 
           [0028]      FIG. 18  is a cross-sectional view of the yoke of  FIG. 1 , taken generally through the shaft retaining pawls. 
           [0029]      FIG. 19  is a cross-sectional view of the yoke of  FIG. 1 , taken generally through the insert retaining members and the shaft retaining pawls. 
           [0030]      FIG. 20  is a cross-sectional view of the yoke of  FIG. 1 , taken generally through the insert retaining members. 
           [0031]      FIG. 21  is a perspective view of an insert of the yoke of  FIG. 1 . 
           [0032]      FIG. 22  is another perspective view of the insert of  FIG. 21 . 
           [0033]      FIG. 23  is a front view of the insert of  FIG. 21 . 
           [0034]      FIG. 24  is a rear view of the insert of  FIG. 21 . 
           [0035]      FIG. 25  is a top view of the insert of  FIG. 21 . 
           [0036]      FIG. 26  is a bottom view of the insert of  FIG. 21 . 
           [0037]      FIG. 27  is a side view of the insert of  FIG. 21 . 
           [0038]      FIG. 28  is an opposite side view of the insert of  FIG. 21 . 
           [0039]      FIG. 29  is a cross-sectional view of the insert of  FIG. 21 . 
           [0040]      FIG. 30  is another cross-sectional view of the insert of  FIG. 21 . 
           [0041]      FIG. 31  is a front perspective view of an alternative construction of a collet locking yoke. 
           [0042]      FIG. 32  is a front perspective view of the yoke of  FIG. 31  with the retaining ring removed. 
           [0043]      FIG. 33  is another front perspective view of the yoke of  FIG. 31 . 
           [0044]      FIG. 34  is a front perspective view of the yoke of  FIG. 31  with the retaining ring removed. 
           [0045]      FIG. 35  is a front perspective view of the yoke of  FIG. 31  with the insert and the retaining ring removed. 
           [0046]      FIG. 36  is a front view of the yoke of  FIG. 31 . 
           [0047]      FIG. 37  is a front view of the yoke of  FIG. 31  with the retaining ring removed. 
           [0048]      FIG. 38  is a rear view of the yoke of  FIG. 31 . 
           [0049]      FIG. 39  is a top view of the yoke of  FIG. 31 . 
           [0050]      FIG. 40  is a bottom view of the yoke of  FIG. 31 . 
           [0051]      FIG. 41  is a side view of the yoke of  FIG. 31 . 
           [0052]      FIG. 42  is an opposite side view of the yoke of  FIG. 31 . 
           [0053]      FIG. 43  is front perspective view of the yoke of  FIG. 31  with the insert and the retaining ring removed. 
           [0054]      FIG. 44  is a front view of the yoke of  FIG. 31  with the insert and the retaining ring removed. 
           [0055]      FIG. 45  is a cross-sectional view of the yoke of  FIG. 31 , taken generally in a vertical plane through the axis. 
           [0056]      FIG. 46  is a front perspective view of an insert of the yoke of  FIG. 31 . 
           [0057]      FIG. 47  is another front perspective view of the insert of  FIG. 46 . 
           [0058]      FIG. 48  is a rear perspective view of the insert of  FIG. 46 . 
           [0059]      FIG. 49  is a front view of the insert of  FIG. 46 . 
           [0060]      FIG. 50  is a rear view of the insert of  FIG. 46 . 
           [0061]      FIG. 51  is a top view of the insert of  FIG. 46 . 
           [0062]      FIG. 52  is a bottom view of the insert of  FIG. 46 . 
           [0063]      FIG. 53  is a side view of the insert of  FIG. 46 . 
           [0064]      FIG. 54  is an opposite side view of the insert of  FIG. 46 . 
           [0065]      FIG. 55  is a cross-sectional view of the insert of  FIG. 46 . 
           [0066]      FIG. 56  is another cross-sectional view of the insert of  FIG. 46 . 
           [0067]      FIG. 57A  is a side view of the yoke of  FIG. 31 . 
           [0068]      FIG. 57B  is a top view of the yoke of  FIG. 31 . 
           [0069]      FIG. 58A  is a front view of the insert of  FIG. 46 . 
           [0070]      FIG. 58B  is a top view of the insert of  FIG. 46 . 
           [0071]      FIG. 58C  is a perspective view of the insert of  FIG. 46 . 
           [0072]      FIG. 58D  is a cross-sectional view of the insert of  FIG. 46 , taken along the line C-C in  FIG. 58E . 
           [0073]      FIG. 58E  is a cross-sectional view of the insert of  FIG. 46 , taken along the line A-A in  FIG. 58D . 
           [0074]      FIG. 58F  is a cross-sectional view of the insert of  FIG. 46 , taken along the line B-B in  FIG. 58D . 
           [0075]      FIG. 59A  is a front view of a hub of the yoke of  FIG. 31 . 
           [0076]      FIG. 59B  is a side view of the hub of  FIG. 59A . 
           [0077]      FIG. 59C  is an enlarged view of Detail A in  FIG. 59B . 
           [0078]      FIG. 59D  is an enlarged view of Detail B in  FIG. 59B . 
           [0079]      FIG. 60  is a partially exploded view of the yoke of  FIG. 31  showing magnitudes of stress from use. 
           [0080]      FIG. 61  is a front perspective view of another alternative construction of a collet locking yoke. 
           [0081]      FIG. 62  is a front perspective view of the yoke of  FIG. 61  with a retaining ring removed. 
           [0082]      FIG. 63  is an exploded view of the yoke of  FIG. 61 . 
           [0083]      FIG. 64  is a front view of the yoke of  FIG. 61  with the retaining ring removed. 
           [0084]      FIG. 65  is a rear view of the yoke of  FIG. 61 . 
           [0085]      FIG. 66  is a top view of the yoke of  FIG. 61 . 
           [0086]      FIG. 67  is a bottom of the yoke of  FIG. 61 . 
           [0087]      FIG. 68  is a side view of the yoke of  FIG. 61 . 
           [0088]      FIG. 69  is an opposite side view of the yoke of  FIG. 61 . 
           [0089]      FIG. 70  is a front perspective view of the yoke of  FIG. 61  with an insert and the retaining ring removed. 
           [0090]      FIG. 71  is a front view of the yoke of  FIG. 61  with the insert and the retaining ring removed. 
           [0091]      FIG. 72  is a cross-sectional view of the yoke of  FIG. 61 . 
           [0092]      FIG. 73  is a front perspective view of the insert of  FIG. 61 . 
           [0093]      FIG. 74  is another front perspective view of the insert of  FIG. 73 . 
           [0094]      FIG. 75  is a front view of the insert of  FIG. 73 . 
           [0095]      FIG. 76  is a rear view of the insert of  FIG. 73 . 
           [0096]      FIG. 77  is a top view of the insert of  FIG. 73 . 
           [0097]      FIG. 78  is a bottom view of the insert of  FIG. 73 . 
           [0098]      FIG. 79  is a side view of the insert of  FIG. 73 . 
           [0099]      FIG. 80  is an opposite side view of the insert of  FIG. 73 . 
           [0100]      FIG. 81  is a cross-sectional view of the insert of  FIG. 73 . 
           [0101]      FIG. 82  is another cross-sectional view of the insert of  FIG. 73 . 
       
    
    
     DETAILED DESCRIPTION 
       [0102]    Before any independent embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other independent embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
         [0103]    Use of “including” and “comprising” and variations thereof as used herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Use of “consisting of” and variations thereof as used herein is meant to encompass only the items listed thereafter and equivalents thereof. 
         [0104]      FIGS. 1-82  illustrate motion transmitting mechanisms and components, such as yoke assemblies for coupling a farm implement to a tractor. Exemplary devices are shown and described in U.S. Pat. No. 5,779,385, filed Jan. 16, 1997, the entire contents of which are hereby incorporated by reference. 
         [0105]    Referring to  FIGS. 1-30 , a collet locking yoke  10  generally includes a yoke  14 , a hub  18 , and a collar  22  slidable on the hub  18 . The illustrated hub  18  defines a hub bore  26  which receives an insert  30  through an end  102 , and a retaining ring  168  abuts the front end  40  of the insert  30  and the hub bore  26  proximate the front end  102 . The opposite end  106  of the hub  18  mates with an end  110  of the yoke  14 . The hub  18  defines a number of radial openings  68  and  72 , and an outer surface of the hub  18  also defines a circumferential groove  148  proximate the front end  102 . 
         [0106]    The collar  22  (see  FIGS. 5-7 ) is annular and has opposite ends  114 ,  118 . The rear end  118  is larger in diameter than the front end  114 . As best shown in  FIGS. 16-17 , the collar  22  has an outer surface  122  that expands from the front end  114  to the rear end  118 . Further, the collar  22  has an inner surface  140  defining (see  FIG. 16 ) a pocket  144  between the ends  114 ,  118 . A snap ring  160  fits within the circumferential groove  148  in the hub  18 . A spring  164  (i.e., a compression spring), shown in  FIGS. 16-17 , abuts the outer surface  122  of the hub  18  and extends from the inner surface  140  of the collar  22  to a radially-outwardly extending ridge of the hub  18 . 
         [0107]    The insert  30  is shaped and sized to receive a splined shaft (not shown) through an end  40  of the insert  30 . In the illustrated construction, the splined shaft may be, for example, a six-spline power take off (PTO) shaft of a tractor. As best shown in  FIGS. 21-24 , the insert  30  has a side wall  42  and defines an insert bore  44  defining insert grooves  48  separated by radially-inward extending splines  52 . The splines  52  have generally trapezoidal-shaped cross-sections and sloped surfaces facing towards the end  40 . The insert bore  44 , the grooves  48 , and the splines  52  together define an inner surface  56  which mates with the shaft. 
         [0108]    The insert  30  has an outer surface  60  shaped and sized to mate with the hub bore  26 . In the illustrated construction, the outer surface  60  of the insert  30 , as best seen in  FIGS. 23-24 , has a hexagonal cross-section. The hub bore  26  (see  FIG. 10 ) has a cross-section which is complementary to and provides a driving engagement with the outer surface  60  of the insert  30  (in the illustrated construction, also hexagonal). 
         [0109]    In the illustrated construction, a releasable insert retainer assembly is provided between the hub  18  and the insert  30 . The insert  30  defines a number of retainer openings  70  extending from the outer surface  60  toward the inner surface  56  aligned with the openings  68  in the hub  18  when the insert  30  is supported in the hub  18 . Each retainer opening  70  (and each associated hub opening  68 ) is shaped (e.g., round (as shown), rectangular, etc.) and sized to receive an insert retaining member  74  (e.g., a pin, a ball, etc.). In the illustrated construction, the insert retainer assembly includes four openings  70  and members  74 . As shown in  FIG. 5 , the illustrated insert retainer members  74  are generally cylindrical with rounded ends. 
         [0110]    Each retainer opening  70  has a reduced diameter at its radially inward end to prevent the retaining member  74  from extending too far into the bore  44  and/or from falling radially into the bore  44  (e.g., to limit or prevent interference with the shaft). In the illustrated construction, the insert retainer assembly is arranged proximate a rear end  78  of the insert  30  and along a center of the associated side of the insert  30 . 
         [0111]    The retaining members  74  extend through the hub openings  68  and partially into the insert openings  70  to releasably retain the insert  30  in the hub  18 . As best shown in  FIGS. 16-29 , the retaining members  74  abut the inner surface  140  of the collar  22  proximate the rear end  118  of the collar  22 . 
         [0112]    In the illustrated construction, a shaft retainer assembly is provided between the hub  18  and the shaft. To accommodate the shaft retainer assembly, the insert  30  also defines a number of openings  82  aligned with the openings  72  in the hub  18  when the insert  30  is supported in the hub  18 . Each opening  82  (and each associated hub opening  72 ) is, each shaped (e.g., round, rectangular (square (as shown)), etc.) and sized to receive a shaft retainer member (e.g., a pawl  84 , a pin, a ball, etc.) such that the pawls  84  engage the shaft when the shaft is received in the bore  44  to limit relative movement. In the illustrated construction, the shaft retainer assembly includes two openings  82  and pawls  84 . 
         [0113]    The illustrated pawls  84  are generally rectangular with angled end surfaces to facilitate insertion and removal of the shaft. Each opening  82  allows movement of the associated pawl  84  during insertion and removal of the shaft. Each opening  82  is also arranged along a center of the associated side of the insert  30  and more toward the rear end  78  than the front end  40 . 
         [0114]    The pawls  84  engage the inner surface  140  of the collar  22  proximate the rear end  118 . The pawls  84  further extend through the hub openings  72  and through the insert openings  82  into the insert bore  44 . The ends of the pawls  84  extending into the insert bore  44  mate with a groove in the shaft when the shaft is received in the bore  44  to limit relative movement. 
         [0115]    The hub  18  and the insert  30  cooperate to apply a clamping force to the shaft when torque is applied. The insert  30  further defines one or more slots  90  in the side wall  42  to allow movement of the side wall  42  (e.g., compression and expansion of the insert  30 ). The arrangement of the outer surface  60  of the insert  30  and the inner surface of the hub bore  26  causes compression of the insert  30  when torque is applied, and this compression causes the insert  30  to flex inwardly and apply a clamping force on the shaft. 
         [0116]    In general, the outer surface  60  of the insert  30  and/or the inner surface of the hub bore  26  are configured to transmit torque and to provide an inwardly-directed force on the insert  30 . In other words, the outer surface  60  of the insert  30  and/or the inner surface of the hub bore  26  have an orientation between a solely circumferential orientation and a solely radial orientation. When torque is applied, the arrangement provides both a torque-transmitting force vector and an inwardly-directed insert-compressing force vector. As mentioned above, in the illustrated construction, the outer surface  60  of the insert  30  and the hub bore  26  have a hexagonal shape, with each engaging surface portion providing both torque transmission and compression. 
         [0117]    The clamping force to be applied and the torque to apply the clamping force may be adjusted by changing the engagement between the outer surface  60  of the insert  30  and the hub bore  26 . For example, looking at  FIGS. 9-10 and 23 , increasing the angle (becoming closer to a radial orientation) at the interface between the outer surface  60  of the insert  30  and the hub bore  26  (e.g., proximate the vertex) increases the force vector for torque transmission while decreasing the inwardly-directed insert-compressing force vector. Thus, compared to the illustrated angles, more torque is required to provide a comparable compression of the insert  30 , and the insert  30  may be “activated” (to apply a clamping force) relatively later, after reaching the higher torque level. Also, in this arrangement, for a given torque, compression of the insert  30  would be reduced, and less clamping force would be applied by the insert  30 . 
         [0118]    Meanwhile, decreasing the angle (becoming closer to a circumferential orientation) at the interface decreases the force vector for torque transmission while increasing the inwardly-directed insert-compressing force vector. Thus, compared to the illustrated angles, less torque is required to provide a comparable compression of the insert  30 , and the insert  30  may be “activated” (to apply a clamping force) relatively earlier, after reaching the lower torque level. In this arrangement, for a given torque, compression of the insert  30  would be increased, and more clamping force would be applied by the insert  30 . 
         [0119]    Accordingly, the outer shape of the insert  30  may be initially selected for a desired clamping force/torque relationship. Compared to the illustrated hexagonal cross-section, a square cross-section would provide an increased angle and require more torque to activate the insert  30  while an octagonal cross-section would provide a decreased angle and require less torque to activate the insert  30 . In still other constructions (not shown), the outer surface  60  of the insert  30  and/or the hub bore  26  may have a different shape (e.g., star-shaped, scallop-shaped, etc.) with convex portions, non-linear surfaces, etc. 
         [0120]    In some constructions (not shown), the angle proximate the interface may change during operation. For example, the shape of the outer surface  60  of the insert  30  and/or the inner surface of the hub bore  26  may not be constant but may change along the interface. As torque is applied, the location where the force is being applied may change along this non-constant interface, and the clamping force/torque level for activation may change. In a specific example, the shape of the outer surface  60  of the insert  30  and/or the inner surface of the hub bore  26  may be arranged to provide early activation of the insert  30  (a shallow angle at the interface) and then to provide a constant clamping force as torque increases (a rising angle). In another example, the shape of the outer surface  60  of the insert  30  and/or the inner surface of the hub bore  26  may be arranged to provide delayed activation of the insert  30  (a steep angle at the interface) and then to provide a rapidly-increasing clamping force as torque increases (a decreasing angle). 
         [0121]    In the illustrated construction, the slot(s)  90  extend from one end toward the other end of the insert  30 . Each illustrated slot  90  is arranged along the center of the associated side of the insert  30  and through a center of an opening  70  or  82 , where provided. A thickness  94  of material is provided at the base of each slot  90 , and, in the illustrated construction, the base of each slot  90  is curved. 
         [0122]    As illustrated, a number of slots  90   a  (e.g., three) extend from the front end  40  toward the rear end  78 , and a number of slots  90   b  (e.g., three) extend from the rear end  78  toward the front end  40 , such that, in the illustrated construction, as best shown in  FIGS. 21-30 , there are six such slots  90 . With grooves  90   a,    90   b  extending from each end  40 ,  78 , the insert  30  is compressed and clamping force is applied to the shaft at each end of the insert  30 . The illustrated slots  90   a,    90   b  alternate circumferentially about the insert  30  which contributes to centering of the shaft in the insert  30 . 
         [0123]    In other constructions (not shown), the insert  30  can define different numbers of slots  90 , including more or fewer than the six slots  90  as illustrated. The slot(s)  90  may be in different locations on the insert  30 . For example, in  FIGS. 73-82 , the slots  90 B extend only from one end  40 B. As other examples, the slot(s)  90  may not be along the center of the side of the insert  30 , may not extend through an end  40 ,  78  of the insert  30  (be located intermediate the ends  40 ,  78 ), etc. The slot(s)  90  may have a different orientation on the insert  30  (e.g., not aligned with the axis of the insert (skewed; not shown), non-linear (curved; not shown), combinations, etc.), shape (e.g., the base of each slot  90  may be square (see  FIGS. 73-82 )), the slot(s)  90  may have non-parallel walls, etc.), etc. 
         [0124]    The flexibility of the insert  30 , which may affect the clamping force applied, the torque to apply the clamping force, etc., may be adjusted. For example, the thickness  94  of material can be increased to reduce the flexibility or decreased to increase the flexibility. The thickness of the wall  42  of the insert  30  can similarly be adjusted to increase or decrease the flexibility of the insert  30 . Material(s) of the insert  30  may also be selected to provide a desired flexibility/range. 
         [0125]    To assemble the yoke  10 , the rear end  118  of the hub  18  is coupled to the front end  110  of the yoke  14 . The pawls  84  and the retaining members  74  are inserted into the respective openings  68 ,  72  in the hub  18 . The spring  164  is placed about the outer surface of the hub  18  and is compressed towards the rear end  106  of the hub  18 . The collar  22  is placed about the outer surface  122  of the hub  18 , and, with the spring  164  under compression, the snap ring  160  can be placed in the circumferential groove  148 . The spring  164  can then be uncompressed, as the snap ring  160  will hold the front end  114  of the collar  22  in place against the force of the spring  164 . The collar  22  radially retains both the pawls  84  and the retaining members  74  within the yoke  10 . 
         [0126]    To place the insert  30  into the hub  18 , the collar  22  is pushed back toward the rear end  106  of the hub  18 , allowing the pawls  84  and the retaining members  74  to move radially outwardly and into the pocket  144 . The insert  30  is then slip fit into the hub  18 , with the insert pawl openings  82  aligned with the hub pawl openings  72  and the insert retaining member openings  70  aligned with the hub retaining member openings  72 . 
         [0127]    The retaining ring  168  is compressed and inserted into the hub  18  to abut the front end  40  of the insert  30  and to cooperate with the retaining members  74  to retain the insert  30  in the hub  18 . The collar  22  is released and moves forward under the force of the spring  164  until engaging the snap ring  160 . With assembly of the yoke  10  complete, the retaining members  74  axially retain the insert  30  in the hub  18 . 
         [0128]    In use, the shaft is inserted into the bore  44  of the insert  30  with a slip fit, with the splines of the shaft within the insert grooves  48  and the splines  52  of the insert  30  between the shaft splines. The pawls  84  move into a circumferential groove in the shaft and shaft splines to axially retain the shaft in the hub  18 . The pawls  84  also cooperate to retain the insert  30  in the hub  18 . 
         [0129]    During operation, a driving force is applied to the motion-transmitting mechanism (e.g., the shaft is driven by an external means (not shown, e.g., a tractor)). The splines of the shaft engage the splines  52  of the insert  30  to transmit torque on the insert  30 . The outer surface  60  of the insert  30  engages the hub bore  26 . Through engagement of the outer surface  60  of the insert  30  and the hub bore  26 , torque is transmitted to the hub  18  and therethrough to the yoke  14  and to any implement (not shown) coupled to the yoke  14 . 
         [0130]    As discussed above, as torque is applied, the engaging surface portions of the outer surface  60  of the insert  30  and the hub bore  26  provide both torque transmission and compression. The insert  30  is “activated”—compressed and flexes to apply a clamping force to the shaft. As also discussed above, the clamping force applied and the torque for activation of the insert  30  is related to the shape of the interface between the outer surface  60  of the insert  30  and the hub bore  26  as well as the arrangement of the slot(s)  90 . 
         [0131]    To remove the shaft, rotation of the shaft is first stopped. Ceasing rotation of the shaft and transmission of torque removes the clamping force exerted on the shaft by the insert  30 . The collar  22  is retracted to allow the pawls  84  to move outwardly and the shaft to be removed. 
         [0132]    To remove the insert  30 , the retaining ring  168  is removed. The collar  22  is retracted to allow the pawls  84  and the retaining members  74  to move outwardly from the respective openings  70 ,  82  in the insert  30 . The insert  30  can then be removed. The insert  30  or a new insert (not shown) can be replaced as described above. The new insert may be provided to replace a worn insert  30  or to provide an insert having a different configuration (e.g., different splines (number, shape), grooves, dimensions, material(s), etc.). 
         [0133]      FIGS. 31-60  illustrate an alternative embodiment of a collet locking yoke  10 A. The yoke  10 A and its components are similar to the yoke  10  and components shown in  FIGS. 1-30  and described above. Common components have the same reference number “A.” The yoke  10 A is assembled and operated in a similar fashion as the yoke  10 . 
         [0134]    The yoke  10 A is a larger version of a constant velocity yoke compared to the yoke  10  which is a middle size constant velocity yoke. As illustrated, the insert  30 A has (see  FIGS. 48  and  51 - 54 ) a flat surface at the rear end  78 A and (see  FIGS. 46-47 and 51-54 ) an increased taper of the edges at the front end  40 A, compared to the insert  30 . 
         [0135]      FIGS. 61-82  illustrate another alternative embodiment of a collet locking yoke  10 B. The yoke  10 B and its components are similar to the yoke  10 ,  10 A, and components shown in  FIGS. 1-30 and 31-60 , respectively, and described above. Common components have the same reference number “B.” The yoke  10 B is assembled and operated in a similar fashion as the yoke  10 ,  10 A. 
         [0136]    The yoke  10 B is a large standard yoke and includes an integral yoke  14 B and hub  18 B. The insert  30 B defines only slots  90 B extending from one end (e.g., the front end  40 B) toward the other end (e.g., the rear end  78 ). This arrangement of the slots  90 B provides clamping force on the shaft proximate the one end (e.g., the front end  40 ) during torque transmission. The base of the illustrated slots  90 B is square. 
         [0137]    In the illustrated constructions, the inserts  30 ,  30 A,  30 B are formed of steel. The illustrated hexagonal inserts  30 ,  30 A,  30 B may be formed from commonly-available steel hex bar stock by machining, forging, etc., to provide the illustrated structure (e.g., the bore  44  (with the grooves  48  and the splines  52 ), the openings  70 ,  82 , the slot(s)  90 ). In other constructions, the inserts  30 ,  30 A,  30 B may be formed of other suitable materials, such as powdered metal, and in an appropriate process (e.g., forging, investment casting, extrusion, etc.) to provide the illustrated structure. 
         [0138]    In the yokes  10 ,  10 A,  10 B, clamping of the insert  30 ,  30 A,  30 B on the shaft during rotation of the shaft and torque transmission reduces or eliminates vibrations during operation. In other words, play between the insert  30 ,  30 A,  30 B and the shaft (beneficial for insertion and removal of the shaft) is reduced when torque is transmitted. 
         [0139]    In some constructions, rotation of the shaft at “no load” is sufficient to cause the insert  30 ,  30 A,  30 B to compress and apply a clamping force on the shaft sufficient to eliminate vibration, play, etc. 
         [0140]    The six spline shaft with which the insert  30 ,  30 A,  30 B mates is designed to operate at 540 revolutions per minute (RPM). At higher speeds (e.g., 1,000 RPM), however, vibrations may be experienced. Such vibrations can cause unease to the operator, who may believe the machine is worn or starting to fail, discomfort, etc. Further, vibrations may lead to wear and eventual failure of the shaft and/or components of the yoke  10 ,  10 A,  10 B. 
         [0141]    With the illustrated slots  90 ,  90 A,  90 B spaced about the circumference of the insert  30 ,  30 A,  30 B compression of and the clamping force exerted on the shaft by the insert  30 ,  30 A,  30 B contributes to centering of the shaft in the insert  30 ,  30 A,  30 B and the hub  18 ,  18 A,  18 B. Centering the shaft provides smoother operation of the shaft and the yoke  10 ,  10 A,  10 B. 
         [0142]    This centering of the shaft may be especially useful in a straight sided “type 1” tractor PTO shaft (see, e.g., International Standards Organization (ISO) 500 for agricultural tractors), which is not self-centering, but may also be beneficial for self-centering shafts with involute or curved splines. Further, as discussed above, ceasing rotation of the shaft and torque transmission eliminates the clamping force on the shaft and allows the shaft to be easily removed, as needed. 
         [0143]    By using the yokes  10 ,  10 A,  10 B and the inserts  30 ,  30 A,  30 B shown above, a shaft designed to rotate at one speed (e.g., at 540 RPM) can be operated a higher speed (e.g., at 1,000 RPM or higher) without increased vibration or different components. This ability to increase the operating speed of the shaft without using a different shaft and/or yoke may meet a growing market need. For example, in many PTO systems, the type 1 shaft has to be replaced with a “type 2” or “type 3” shaft for applications at speeds higher (e.g., 1,000 RPM) than the type 1 shaft was designed (540 RPM). 
         [0144]    Further, even higher RPMs could be accommodated by use of the yokes  10 ,  10 A,  10 B, and the inserts  30 ,  30 A,  30 B described above. For example, new, larger and heavier drive shafts (e.g., shafts designed to run at 1540 RPM) are becoming more prominent. These heavier shafts and the associated yokes are even more sensitive to vibration than lighter shafts/yokes and may benefit even further from mating with vibration-reducing, shaft-centering yokes  10 ,  10 A,  10 B and inserts  30 ,  30 A,  30 B as described above. 
         [0145]    In other constructions (not shown), an insert may have a different construction (e.g., a different shaft interface (not shown) to mate with a different shaft, formed of different material(s), etc.) while still being usable with the yoke  10  and insertable into the hub bore  26 . For example, such an alternative insert may have an interface configured to receive a twenty-one splined shaft. In such a construction, the twenty-one spline insert may have an outer surface similar to the six spline insert  30  and/or complementary to the shape of/able to be in driving engagement with the hub bore  26 . 
         [0146]    Independent of the compressible, clamping features, the arrangement of a removable/replaceable insert  30 ,  30 A,  30 B in the hub bore  26 ,  26 A,  26 B of the yoke  10 ,  10 A,  10 B may provide a modular arrangement such that a given yoke  10 ,  10 A,  10 B may be used with machines having different shafts (e.g., type 1, 2, 3, etc.). This arrangement may also independently provide replacement of the insert  30 ,  30 A,  30 B, as needed, due to wear, failure, etc., for example, of the shaft interface in the insert bore  44 . 
         [0147]    One or more independent features and/or independent advantages of the invention may be set forth in the following claims: