Abstract:
Shaft locking assemblies for a drive shaft include an assembly hub configured to accommodate the drive shaft, the assembly hub including a stop plate; an assembly hub interior in the assembly hub; a contractible shaft locking sleeve disposed in the assembly hub interior and configured to accommodate the drive shaft, the shaft locking sleeve engaging the stop plate; at least one pusher sleeve engaging the shaft locking sleeve; a fluid pressure space disposed in pressure transmitting relationship to the pusher sleeve; and a fluid pressurizing mechanism disposed in fluid communication with the fluid pressure space. The pusher sleeve is adapted to push against the shaft locking sleeve and the shaft locking sleeve is adapted to contract and push against the stop plate and contract against the drive shaft responsive to introducing a pressurizing fluid into the fluid pressure space. Methods of locking a rotating element on a drive shaft are also disclosed.

Description:
FIELD 
     Illustrative embodiments of the disclosure generally relate to devices for securing a rotating element to a drive shaft. More particularly, illustrative embodiments of the disclosure relate to shaft locking assemblies and methods in which a drum or other rotating element is locked onto a drive shaft using a pressurizing fluid and which is suitable for applications in which a large magnitude of resistance is applied to the rotating element. 
     BACKGROUND 
     The background description provided herein is solely for the purpose of generally presenting the context of the illustrative embodiments of the disclosure. Aspects of the background description are neither expressly nor impliedly admitted as prior art against the claimed subject matter. 
     Various types of devices and techniques are used to attach a rotating element to a drive shaft. However, in applications in which a large magnitude of pressure is applied to the rotating element, such as in the operation of a draw works which raises and lowers a traveling block in oil and gas drilling and recovery operations, for example, the structural and operational integrity of these devices and techniques may be compromised. 
     Accordingly, shaft locking assemblies and methods in which a drum or other rotating element is locked onto a drive shaft using a pressurizing fluid and which is suitable for applications in which a large magnitude of pressure is applied to the rotating element may be desirable for some applications. 
     SUMMARY 
     Illustrative embodiments of the disclosure are generally directed to shaft locking assemblies for a drive shaft. An illustrative embodiment of the shaft locking assemblies includes an assembly hub configured to accommodate the drive shaft, the assembly hub including a stop plate; an assembly hub interior in the assembly hub; a contractible shaft locking sleeve disposed in the assembly hub interior and configured to accommodate the drive shaft, the shaft locking sleeve engaging the stop plate; at least one pusher sleeve engaging the shaft locking sleeve; a fluid pressure space disposed in pressure transmitting relationship to the pusher sleeve; and a fluid pressurizing mechanism disposed in fluid communication with the fluid pressure space. The pusher sleeve is adapted to push against the shaft locking sleeve and the shaft locking sleeve is adapted to contract and push against the stop plate and contract against the drive shaft responsive to introducing a pressurizing fluid into the fluid pressure space. 
     In some embodiments, the shaft locking assemblies may be adapted for a drive shaft having a drive segment, a driven segment and a shaft gap between the drive segment and the driven segment. The shaft locking assemblies may include an assembly hub including a stop plate; a distal pusher sleeve engaging the stop plate; a contractible shaft locking sleeve engaging the distal pusher sleeve, the shaft locking sleeve adapted to straddle the shaft gap between the drive segment and the driven segment of the drive shaft; a proximal pusher sleeve engaging the shaft locking sleeve; a push plate engaging the proximal pusher sleeve; a fluid pressure space disposed in pressure transmitting relationship to the proximal pusher sleeve; and a fluid pressurizing mechanism disposed in fluid communication with the fluid pressure space. The proximal pusher sleeve is adapted to push against the shaft locking sleeve, the shaft locking sleeve is adapted to push against the distal pusher sleeve and the shaft locking sleeve is adapted to contract and push against the drive shaft segment and the driven shaft segment of the drive shaft responsive to introducing a pressurizing fluid into the fluid pressure space. 
     Illustrative embodiments of the disclosure are further generally directed to methods of locking a rotating element on a drive shaft. An illustrative embodiment of the methods includes mounting the rotating element on an assembly hub of a shaft locking assembly, applying a pressurizing fluid against at least one pusher sleeve, applying the pusher sleeve against a shaft locking sleeve and applying the shaft locking sleeve against the drive shaft and the assembly hub. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Illustrative embodiments of the disclosure will now be described, by way of example, with reference to the accompanying drawings, in which: 
         FIG. 1  is a front view of a swab rig having a draw works including an illustrative embodiment of the shaft locking assembly in exemplary implementation of the shaft locking assembly; 
         FIG. 2  is a front view of a drum on the draw works, a drum motor drivingly engaging the drum and the illustrative shaft locking assembly coupling the drum to the drum motor in exemplary application of the shaft locking assembly; 
         FIG. 3  is an end view of the drum illustrated in  FIG. 2 , with the shaft locking assembly coupling the drum to the drum motor (not illustrated); 
         FIG. 4  is an exploded side view, partially in section, of an exemplary fluid inlet conduit of the shaft locking assembly, more particularly illustrating detachable coupling of a fluid inlet hose to the fluid inlet conduit in exemplary application of the shaft locking assembly; 
         FIG. 5  is an exploded side view, partially in section, of an exemplary fluid outlet conduit of the shaft locking assembly, more particularly illustrating detachable coupling of a fluid outlet hose to the fluid outlet conduit in exemplary application of the shaft locking assembly; 
         FIG. 6  is a functional block diagram of an exemplary fluid pressurizing system suitable for implementation of an illustrative embodiment of the shaft locking assembly; 
         FIG. 7  is a longitudinal sectional view of the drum of the draw works with an illustrative embodiment of the drum locking assembly coupling the drum to the drum motor; 
         FIG. 8  is a side view of an exemplary shaft locking sleeve of the drum locking assembly; 
         FIG. 9  is a rear view of the exemplary shaft locking sleeve; 
         FIG. 10  is a front view of the exemplary shaft locking sleeve; 
         FIG. 11  is a side view of an exemplary pusher sleeve of the drum locking assembly; 
         FIG. 12  is a rear view of the exemplary pusher sleeve; 
         FIG. 13  is a front view of the exemplary pusher sleeve; 
         FIG. 14  is an enlarged longitudinal sectional view of the drum locking assembly; 
         FIG. 15  is an enlarged longitudinal sectional view of the drum locking assembly disposed in a depressurized shaft-disengaging configuration; 
         FIG. 16  is an enlarged longitudinal sectional view of the drum locking assembly disposed in a pressurized shaft-engaging configuration; 
         FIG. 17  is a longitudinal sectional view of the drum of the draw works with an alternative illustrative embodiment of the drum locking assembly for coupling the drum to the drum motor; 
         FIG. 18  is an enlarged longitudinal sectional view of the drum locking assembly of  FIG. 17 , disposed in a depressurized shaft-disengaging configuration; 
         FIG. 19  is an enlarged longitudinal sectional view of the drum locking assembly of  FIG. 17 , disposed in a pressurized shaft-engaging configuration; and 
         FIG. 20  is a flow diagram of an illustrative embodiment of a shaft locking method. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable users skilled in the art to practice the disclosure and are not intended to limit the scope of the claims. Moreover, the illustrative embodiments described herein are not exhaustive and embodiments or implementations other than those which are described herein and which fall within the scope of the appended claims are possible. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. While the description of the shaft locking assemblies and methods will be hereinafter described with respect to operation of a swab rig which is used to remove water from a hydrocarbon-producing well, it will be recognized and understood that the shaft locking assemblies and methods are equally applicable to drilling and workover rigs as well as applications outside the oil and gas drilling and recovery industry. 
     Referring initially to  FIGS. 1 and 2  of the drawings, a swab rig  1  ( FIG. 1 ) in exemplary implementation of an illustrative embodiment of the shaft locking assembly  40  is illustrated. The swab rig  1  may be used to remove water from a subterranean hydrocarbon production well for the purpose of enhancing production of hydrocarbons from the well. The swab rig  1  may include a derrick  2  which provides support for a crown block  23  and a traveling block  21  used to raise and lower a drill string  3  into and out of a subterranean well bore, typically in the conventional manner. A draw works  26  may be connected to the crown block  23  and the traveling block  21  via a hoist line  22  to selectively raise and lower the traveling block  21  via the hoist line  22 . 
     As illustrated in  FIG. 2 , the draw works  26  may include a pair of spaced-apart drum stands  27 . A drum  28  on which the hoist line  22  is wound may be rotatably mounted on the drum stands  27 . A drum motor  37  drivingly engages the drum  28  for rotation of the drum  28  on the drum stands  27 . A drum brake  36  engages the drum  28  typically through a taper lock hub  34  ( FIG. 7 ) to slow or stop rotation of the drum  28  on the drum stands  27 . In a manner which will be hereinafter described, the shaft locking assembly  40  may facilitate selective engagement of the drum motor  37  with the drum  28  for rotation of the drum  28  and winding and unwinding of the hoist line  22  on the drum  28  to facilitate raising and lowering of the traveling block  21  and the drill string  3  on the derrick  2 . Accordingly, while the shaft locking assembly  40  will be hereinafter described as applicable to facilitating driving engagement of the drum motor  37  with the drum  28  on the draw works  26  and raising and lowering of the traveling block  21  on the derrick  2  of the swab rig  1 , it will be recognized and understood that the shaft locking assembly  40  is amenable to a variety of other applications in which it is desired to drivingly couple a drive motor or drive shaft to a rotating element, particularly applications in which a large magnitude of resistance is applied to the rotating element. 
     Referring next to  FIGS. 3-16  of the drawings, the shaft locking assembly  40  may include an assembly hub  41 , as illustrated in  FIGS. 7 and 14 . The assembly hub  41  may include a generally cylindrical assembly hub wall  42  and a stop plate  43  which terminates a first end of the assembly hub wall  42 . The stop plate  43  may have a central shaft opening  43   a  which accommodates a drive shaft  38  that is drivingly engaged by the drum motor  37 . An assembly hub interior  45  may be formed by and between the assembly hub wall  42  and the stop plate  43 . 
     An assembly hub flange  44  may terminate a second end of the assembly hub wall  42 . A radial fluid inlet passage  46  and a radial fluid outlet passage  47  may extend through the assembly hub flange  44  for purposes which will be hereinafter described. An annular shaft hub  60  may have a shaft opening  61  which accommodates the drive shaft  38 . The assembly hub flange  44  of the assembly hub  41  may be secured to the shaft hub  60  via threads  68 , at least one hub fastener  49  and/or other suitable securing mechanism known by those skilled in the art. As illustrated in  FIG. 14 , an annular O-ring groove  53  may be provided in the assembly hub flange  44  at the interface with the shaft hub  60  and adjacent to the fluid inlet passage  46  and the fluid outlet passage  47 . An O-ring  53   a  may be provided in the O-ring groove  53  for fluid sealing purposes. 
     As further illustrated in  FIG. 7 , the drum  28  may include a generally elongated, cylindrical drum cylinder  29  opposite ends of which may be welded and/or otherwise secured or attached to the taper lock hub  34  and to the assembly hub  41  of the shaft locking assembly  40 . The taper lock hub  34  may include a drive shaft opening  35  which accommodates the drive shaft  38 . A brake end drum flange  30  and a motor end drum flange  31  may be provided at the respective ends of the drum cylinder  29 . 
     An annular shaft locking sleeve  72  is disposed in the assembly hub interior  45  of the assembly hub  41 . As illustrated in  FIGS. 8-10 , the shaft locking sleeve  72  may include an annular shaft locking sleeve base  73 . A conical or tapered shaft locking sleeve wall  74  may extend from the shaft locking sleeve base  73 . A flat or blunt shaft locking sleeve end  75  may terminate the shaft locking sleeve wall  74 . A shaft locking sleeve bore  76  ( FIGS. 9 and 10 ) may extend through the shaft locking sleeve wall  74  from the shaft locking sleeve base  73  to the shaft locking sleeve end  75 . In some embodiments, a shaft locking sleeve slot  77  which communicates with the shaft locking sleeve bore  76  may extend through the shaft locking sleeve wall  74  from the shaft locking sleeve base  73  to the shaft locking sleeve end  75 . Accordingly, as illustrated in  FIG. 14 , the shaft locking sleeve bore  76  accommodates the drive shaft  38  with the shaft locking sleeve base  73  engaging the interior surface of the stop plate  43  on the assembly hub  41  and the shaft locking sleeve end  75  proximate the shaft hub  60 . 
     An annular pusher sleeve  80  is disposed in the assembly hub interior  45  of the assembly hub  41  in meshing engagement with the shaft locking sleeve  72 . As illustrated in  FIGS. 11-13 , the pusher sleeve  80  may include a generally cylindrical sleeve body  81  having a wide bore end  82  and a narrow bore end  83 . A pusher sleeve bore  84 , having a tapered or conical interior sleeve surface  85 , may extend through the sleeve body  81  from the wide bore end  82  to the narrow bore end  83 . Thus, the wide end of the pusher sleeve bore  84  opens to the wide bore end  82  and the narrow end of the pusher sleeve bore  84  opens to the narrow bore end  83  of the sleeve body  81 . In some embodiments, a pusher sleeve slot  86  which communicates with the pusher sleeve bore  84  may extend through the sleeve body  81  from the wide bore end  82  to the narrow bore end  83 . Accordingly, as illustrated in  FIG. 14 , at the narrow bore end  83 , the pusher sleeve bore  84  accommodates the drive shaft  38 . From the narrow bore end  83  to the wide bore end  82 , the pusher sleeve bore  84  accommodates the diverging shaft locking sleeve wall  74  of the shaft locking sleeve  72 , with the interior sleeve surface  85  of the pusher sleeve  80  engaging the complementary shaped shaft locking sleeve wall  74  of the shaft locking sleeve  72 . The wide bore end  82  of the pusher sleeve  80  engages the stop plate  43  on the assembly hub  41 , and the narrow bore end  83  of the pusher sleeve  80  is proximate the shaft hub  60 . 
     An annular push plate  64  may be provided in the assembly hub interior  45  of the assembly hub  41  in engagement with the narrow bore end  83  of the pusher sleeve  80 . In some embodiments, the push plate  64  may include a push plate base  65  which engages the pusher sleeve  80 . A push plate flange  66  may extend from the push plate base  65 . A pair of elastomeric push plate seals  67  may be provided in the respective spaces on opposite sides of the push plate flange  66  and between the push plate base  65  and the shaft hub  60 . An annular fluid pressure space  70  may be formed by and between the shaft hub  60  and the push plate flange  66  of the push plate  64  and the push plate seals  67  for purposes which will be hereinafter described. The fluid pressure space  70  registers with the fluid inlet passage  46  and the fluid outlet passage  47  in the assembly hub flange  44  of the assembly hub  41 . 
     As illustrated in  FIG. 7 , a fluid inlet conduit  50  and a fluid outlet conduit  54  may be disposed in fluid communication with the fluid inlet passage  46  and the fluid outlet passage  47 , respectively, in the assembly hub flange  44  of the assembly hub  41 . As illustrated in  FIGS. 3 and 7 , in some embodiments, the fluid inlet conduit  50  and the fluid outlet conduit  54  may be attached to the exterior surface of the motor end drum flange  31  of the drum  28  using at least one conduit clamp  57  and/or other suitable attachment technique known by those skilled in the art. As illustrated in  FIG. 4 , a fluid inlet valve  51  may be provided in the fluid inlet conduit  50 . An inlet hose connector  52  may terminate the fluid inlet conduit  50  at the fluid inlet valve  51 . The inlet hose connector  52  facilitates releasable fluid coupling of a fluid inlet hose  90  to the fluid inlet conduit  50  for purposes which will be hereinafter described. As illustrated in  FIG. 5 , a fluid outlet valve  55  may be provided in the fluid outlet conduit  54 . An outlet hose connector  58  may terminate the fluid outlet conduit  54  at the fluid outlet valve  55 . The outlet hose connector  58  facilitates releasable fluid coupling of a fluid outlet hose  92  to the fluid outlet conduit  54  for purposes which will be hereinafter described. In some embodiments, the fluid outlet valve  55  may be fitted with a valve handle  56  which facilitates selective opening and closing of the fluid outlet valve  55  for purposes which will be hereinafter described. 
     In exemplary application of the shaft locking assembly  40 , a fluid pressurizing system  32  ( FIG. 6 ) may be operated to pressurize the pusher sleeve  80  against the shaft locking sleeve  72  such that the shaft locking sleeve  72  is pushed against the drive shaft  38  and the stop plate  43  of the assembly hub  41 , as illustrated in  FIG. 16 , for transmission of rotation from the drive shaft  38  to the drum  28  by operation of the drum motor  37 . As illustrated in  FIG. 6 , the fluid pressurizing system  32  may include a fluid pressurizing mechanism  88 . The fluid pressurizing mechanism  88  may include any type of mechanism, device or technique which is known by those skilled in the art and suitable for pressurization of a pressurizing fluid  94  such as hydraulic fluid, oil or grease, for example and without limitation. The fluid inlet hose  90  and the fluid outlet hose  92  may be disposed in fluid communication with the fluid pressurizing mechanism  88 . The fluid inlet hose  90  and the fluid outlet hose  92  may be adapted for detachable coupling to the inlet hose connector  52  at the fluid inlet valve  51  and to the outlet hose connector  58  at the fluid outlet valve  55 , respectively, as was heretofore described with respect to  FIGS. 4 and 5 , for pressurization and depressurization, respectively, of the shaft locking assembly  40 . Accordingly, with the valve handle  56  ( FIG. 5 ) of the fluid outlet valve  55  in the closed position, the fluid inlet hose  90  is initially coupled to the fluid inlet conduit  50  at the inlet hose connector  52 . Operation of the fluid pressurizing system  32  facilitates flow of the pressurizing fluid  94  through the fluid inlet hose  90 , the inlet hose connector  52 , the fluid inlet valve  51 , the fluid inlet conduit  50 , the fluid inlet passage  46 , the fluid pressure space  70 , the fluid outlet passage  47  and the fluid outlet conduit  54 , respectively, until a predetermined target pressure of the pressurizing fluid  94  in the fluid pressure space  70  is achieved. The fluid inlet hose  90  may next be uncoupled from the inlet hose connector  52 . The fluid inlet valve  51  prevents backflow of the pressurizing fluid  94  from the fluid inlet conduit  50 . The closed fluid outlet valve  55  prevents flow of the pressurizing fluid  94  from the fluid outlet conduit  54 . 
     The pre-pressurized configurations of the pusher sleeve  80  and the shaft locking sleeve  72  are illustrated in  FIG. 15 . Upon flow of the pressurizing fluid  94  from the fluid inlet passage  46  into the fluid pressure space  70 , as was heretofore described, the pressurizing fluid  94  applies pressure against the push plate  64 , which in turn applies pressure against the pusher sleeve  80 , as illustrated in  FIG. 16 . The pusher sleeve  80  in turn applies pressure against the shaft locking sleeve  72 , which contracts and pushes against both the stop plate  43  of the assembly hub  41  and against the drive shaft  38  with a shaft compression force  62 . Consequently, the shaft locking sleeve  72  couples the drive shaft  38  to the drum  28  through the assembly hub  41  and transmits rotation from the drive shaft  38  to the drum  28  responsive to operation of the drum motor  37  to facilitate winding and unwinding of the hoist line  22  on the drum  28  and raising and lowering of the traveling block  21  ( FIG. 1 ) on the derrick  2 . It will be appreciated by those skilled in the art that the presence of the shaft locking sleeve slot  77  ( FIGS. 8 and 10 ) in the shaft locking sleeve  72  and the pusher sleeve slot  86  ( FIGS. 11-13 ) in the pusher sleeve  80  in some embodiments may enable the shaft locking sleeve  72  and the pusher sleeve  80  to contract in the assembly hub interior  45  and increase the pressure which the shaft locking sleeve  72  applies to the drive shaft  38  and the assembly hub  41 . 
     In some illustrative embodiments, the area of the assembly hub  41  in which the pusher sleeve  80  and the shaft locking sleeve  72  are contained may be about 41 square inches. The area of the drive shaft  38  which is contacted by the shaft locking sleeve  72  may be about 14.725 inches, corresponding to an area of about 26.275 square inches of push surfaces on the drive shaft  38  and the stop plate  43 . Thus, at a pressure of 9,000 psi for the pressurizing fluid  94  in the fluid pressure space  70 , the shaft locking sleeve  72  may apply a shaft compression force  62  ( FIG. 16 ) of about 236,475 psi to the drive shaft  38 . 
     After use, the shaft locking assembly  40  can be selectively depressurized by initially connecting the fluid outlet hose  92  to the outlet hose connector  58  and then manipulating the valve handle  56  ( FIG. 5 ) of the fluid outlet valve  55  from the closed position to the open position. This facilitates discharge of the pressurizing fluid  94  from the fluid outlet conduit  54  through the fluid outlet hose  92  and back to the fluid pressurizing mechanism  88  of the fluid pressurizing system  32  ( FIG. 6 ). Accordingly, the pressure of the pressurizing fluid  94  in the fluid pressure space  70  is released such that the drum  28  is uncoupled from the drive shaft  38 . 
     Referring next to  FIGS. 17-19  of the drawings, an alternative illustrative embodiment of the shaft locking assembly is generally indicated by reference numeral  140 . In the shaft locking assembly  140 , elements which are analogous to the respective elements of the shaft locking assembly  40  that was heretofore described with respect to  FIGS. 1-16  are designated by the same numeral in the  100 - 199  series in  FIGS. 17-19 . The shaft locking assembly  140  facilitates selective coupling of a driven segment  138   b  to a drive segment  138   a  of the drive shaft  138 , with the drive motor  137  drivingly engaging the drive segment  138   a . A shaft gap  139  may exist between the drive segment  138   a  and the driven segment  138   b . Accordingly, the shaft locking assembly  140  may include at least one annular pusher sleeve  180 ,  180   a  and an annular shaft locking sleeve  196  which engages the assembly hub  141  and the drive segment  138   a  and the driven segment  138   b  of the drive shaft  138 . In some embodiments, the shaft locking assembly  140  may include an annular proximal pusher sleeve  180  which is engaged by the push plate  164 , an annular shaft locking sleeve  196  which is engaged by the proximal pusher sleeve  180  and a distal pusher sleeve  180   a  which is engaged by the shaft locking sleeve  196  and engages the stop plate  143  of the assembly hub  141 . 
     As illustrated in  FIGS. 18 and 19 , the shaft locking sleeve  196  may include an outer sleeve surface  197  which engages the inner surface of the drum cylinder  129 , an inner sleeve surface  198  which engages the drive segment  138   a  and the driven segment  138   b  and straddles the shaft gap  139  of the drive shaft  138 , and a pair of pusher sleeve engaging surfaces  199  which diverge or taper outwardly from the outer sleeve surface  197  to the inner sleeve surface  198 . The proximal pusher sleeve  180  may include a narrow bore end  183  which is engaged by the push plate  164  and a tapered interior sleeve surface  185  which engages one of the pusher sleeve engaging surfaces  199  of the shaft locking sleeve  196 . The distal pusher sleeve  180   a  may include a narrow bore end  183  which engages the stop plate  143  of the assembly hub  141  and a tapered interior sleeve surface  185  which is engaged by the other pusher sleeve engaging surface  199  of the shaft locking sleeve  196 . In some embodiments, a shaft locking sleeve slot  77  ( FIGS. 8 and 10 ) may be provided in the shaft locking sleeve  196  and a pusher sleeve slot  86  ( FIGS. 11-13 ) may be provided in each of the proximal pusher sleeve  180  and the distal pusher sleeve  180   a.    
     Operation of the shaft locking assembly  140  may be as was heretofore described with respect to operation of the shaft locking assembly  40  in  FIGS. 1-16 . The pre-pressurized configurations of the proximal pusher sleeve  180 , the shaft locking sleeve  196  and the distal pusher sleeve  180   a  are illustrated in  FIG. 18 . Upon flow of the pressurizing fluid  194  into the fluid pressure space  170 , as illustrated in  FIG. 19 , typically by operation of the fluid pressurizing system  32  ( FIG. 6 ), as was heretofore described, the pressurizing fluid  194  applies pressure against the push plate  164 , which in turn applies pressure against the proximal pusher sleeve  180 . The proximal pusher sleeve  180  pushes against the shaft locking sleeve  196 , which pushes against the distal pusher sleeve  180   a . The distal pusher sleeve  180   a  pushes against the stop plate  143 . Accordingly, the shaft locking sleeve  196  is compressed between the proximal pusher sleeve  180  and the distal pusher sleeve  180   a  and contracts against the drive segment  138   a  and the driven segment  138   b  of the drive shaft  138  with a shaft compression force  162 , exerting a shaft joining force  163  which couples the driven segment  138   b  to the drive segment  138   a . Thus, upon operation of the drum motor  137 , rotation is transmitted from the drive segment  138   a  to both the driven segment  138   b  of the drive shaft  138  and to the drum  128  through the shaft locking sleeve  196 . Fluid pressure may be released from the fluid pressure space  170  by coupling of the fluid outlet hose  192  to the outlet hose connector  158  and opening the fluid outlet valve  155  using the valve handle  156 , as was heretofore described with respect to  FIGS. 5 and 6 . 
     Referring next to  FIG. 20  of the drawings, a flow diagram of an illustrative embodiment of a shaft locking method is generally indicated by reference numeral  200 . The shaft locking method  200  may be used to drivingly couple a rotating element to a drive shaft. In some embodiments, the shaft locking method  200  may be used to selectively couple a drum to a drive shaft in a draw works which is operated to selectively raise and lower a traveling block on a derrick of a swab rig, for example and without limitation. At block  202 , a rotating element may be mounted on an assembly hub of a shaft locking assembly. In some embodiments, the rotating element may include a drum on a draw works. At block  204 , a pressurizing fluid may be applied against at least one pusher sleeve of the shaft locking assembly. At block  206 , the pusher sleeve may be pushed against a shaft locking sleeve. At block  208 , the shaft locking sleeve may be applied or contracted against the drive shaft and the assembly hub. In some embodiments, the force of a pressurizing fluid may be applied against a proximal pusher sleeve, the proximal pusher sleeve may be applied against the shaft locking sleeve and the shaft locking sleeve may be applied against a distal pusher sleeve. The shaft locking sleeve may be compressed between the proximal pusher sleeve and the distal pusher sleeve and against the drive shaft to couple a drive segment to a driven segment of the drive shaft. In some embodiments, the pressurizing fluid may be applied against a push plate and the push plate may be applied against the pusher sleeve. At block  210 , rotation may be transmitted from the drive shaft to the rotating element through the assembly hub. 
     While illustrative embodiments of the disclosure have been described above, it will be recognized and understood that various modifications can be made in the disclosure and the appended claims are intended to cover all such modifications which may fall within the spirit and scope of the disclosure.