Patent Publication Number: US-10759639-B2

Title: Linear winch

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present invention is a 35 U.S.C. § 371 U.S. National Stage of International Application No. PCT/GB2016/051809, filed on Jun. 17, 2016, which claims priority to Great Britain Patent Application No. 1511015.8, filed Jun. 23, 2015, the entire content of each of which is incorporated herein by reference. 
     The present invention relates to linear winch assemblies which use grip assemblies to clamp and pull a winch cable, and in particular to an improved gripper assembly for use in such linear winch assemblies. Aspects of the invention include a linear winch assembly including such a gripper assembly and a method of use. 
     BACKGROUND TO THE INVENTION 
     During the installation and maintenance of load bearing cables such as in marine applications, it is necessary to lower and/or raise cables into position. Winch assemblies must be capable of withstanding heavy loads from the weight of the cables and loads attached to the cables. 
     In applications which use relatively short cable lengths with small loads conventional reel winches may be used. However, for longer cable lengths with heavy loads reel winches are not suitable as they require large drums to accommodate the longer cable and may result in unacceptable loading applied to the drum. Furthermore, the reel winch may prevent the tensioning and releasing of the cable from being accurately controlled. 
     It is known to use linear winches in combination with a reel winch. The linear winch is used to pull the cable and maintain the tension on the cable while the reel winch reels or unreels the cable on a reel drum. 
     Linear winches usually comprise two gripper assemblies which clamp and pull the cable in a coordinated operation. As a first gripper assembly grips and pulls the cable a second gripper assembly allows the cable to pass freely. As the second gripper assembly grips and pulls the cable the first gripper assembly releases the cable and slides over the cable to return to its initial position. The successive holding and releasing steps of the two gripper assemblies allows the tension of the cable to be maintained as it is pulled. 
     U.S. Pat. No. 4,569,507 describes a traction block for a linear winch comprising an elongate frame and two clamping blocks which are mounted between lateral flanges on the frame so that a relative longitudinal movement between each movable clamping block and the adjacent flange of the frame causes a transverse movement of the respective movable clamping block. The traction block also comprises a cover plate which is detachable fixed to the traction block. 
     A disadvantage of this system is that the winch must be taken offline, the winch assembly dismantled and components of the winch to be removed in order to lift the cable connector clear of the winch assembly. This is time consuming and dangerous operation especially when the cable is under tension. 
     SUMMARY OF THE INVENTION 
     It is an object of at least one aspect of the present invention to obviate or at least mitigate the foregoing disadvantages of prior art linear winches. 
     It is another object of an aspect of the present invention to provide a linear winch assembly with improved productivity and/or efficiency which is capable of reliably performing a range of winching tasks over a wide range of cable lengths, sizes and loads. 
     It is further object of at least one aspect of the present invention to provide an improved gripper assembly that is capable of improving the performance of a linear winch assembly in which the gripper assembly is deployed. 
     It is another object of an aspect of the present invention to provide a robust, reliable, sturdy linear winch assembly suitable for deployment in a wide range of winching applications which is capable of passing a cable connector whilst maintaining the tension on the cable and prolonging the working lifespan of the linear winch assembly. 
     Further aims and objects of the invention will become apparent from reading the following description. 
     According to a first aspect of the invention, there is provided a linear winch assembly comprising: 
     a first gripper assembly comprising a first gripper block; 
     a second gripper assembly comprising a second gripper block; 
     a first mechanism operable to move at least part of the first gripper block out of the pathway of a cable connector to allow the connector to pass through the first gripper assembly and 
     a second mechanism operable to move at least part of the second gripper block out of the pathway of a cable connector to allow the connector to pass through the second gripper assembly. 
     The above described linear winch assembly may facilitate the passing of a cable connector through the linear winch assembly whilst maintaining the tension on the cable. This may facilitate the efficient winching of long lengths of cable formed from a series of short cables joined by connectors. 
     By providing a linear winch assembly with at least part of the gripper blocks capable of moving out of the pathway of a cable connector, the winch assembly may facilitate the passing of a cable connector through the body of the winch assembly without the use of a crane or lifting mechanism. This may avoid dangerous, cumbersome and time consuming operations which are required when using a crane or lifting mechanism to lift the tensioned cable out of the pathway of components of the linear winch assembly. 
     Preferably the first mechanism is configured move the at least part of the first gripper block to a position which is out of the pathway of the cable connector, wherein the position may be within a linear winch housing. Further preferably the second mechanism is configured to move the at least part of the second gripper block to a position which is out of the pathway of the cable connector, wherein the position may be within a linear winch housing. 
     The first mechanism may be configured to move the at least part of the first gripper block laterally, vertically and/or horizontally to a position out of the pathway of a cable connector. The first mechanism may be configured to rotate, lower, raise and/or displace the at least part of the first gripper block to move out it out of the pathway of the cable connector. 
     The second mechanism may be configured to move the at least part of the second gripper block laterally, vertically and/or horizontally to a position out of the pathway of the cable connector. The second mechanism may be configured to rotate, lower, raise and/or displace the at least part of the second gripper block to move out it out of the pathway of the cable connector. 
     The first mechanism may be configured to move the at least part of the first gripper block from an operative position in which the first gripper block is in the pathway of a cable connector to an inoperative position in which the first gripper block is not in the pathway of a cable connector. 
     The inoperative position of the first gripper block may be laterally, vertically and/or horizontally offset from the operative position of the first gripper block. 
     The cable connector may extend radially outward from the cable to a first radial distance. The inoperative position of the first gripper block may be laterally, vertically and/or horizontally offset from the operative position of the first gripper block by a distance equal to or greater than the first radial distance of the cable connector to allow the cable connector to pass through the first gripper assembly. 
     The second mechanism may be configured to move the at least part of the second gripper block from an operative position in which the second gripper block is in the pathway of a cable connector to an inoperative position in which the second gripper block is not in the pathway of a cable connector. 
     The inoperative position of the second gripper block may be laterally, vertically and/or horizontally offset from the operative position of the second gripper block. 
     The cable connector may extend radially outward from the cable to a first radial distance. The inoperative position of the at least part of the second gripper block may be laterally, vertically and/or horizontally offset from the operative position of the at least part of the second gripper block by a distance equal to/or greater than the first radial distance of the cable connector to allow the cable connector to pass through the second gripper assembly. 
     Preferably, the first mechanism may be configured to move the at least part of the first gripper block to a vertically lower position which is out of the pathway of the cable connector, wherein the position may be within a linear winch housing. 
     Preferably, the second mechanism may be configured to move the at least part of the second gripper block to a vertically lower position which is out of the pathway of the cable connector, wherein the lower position may be within a linear winch housing. 
     The first mechanism may be configured to move the at least part of the first gripper block in a direction substantially transverse to the direction of travel of the cable and/or cable connector. The second mechanism may be configured to move the at least part of the second gripper block in a direction substantially transverse to the direction of travel of the cable and/or cable connector. 
     The first mechanism and/or second mechanism may comprise a hydraulic, pneumatic, electric or mechanical actuator. In some embodiments, the actuator is a hydraulic cylinder. Preferably the first gripper assembly and/or the second gripper assembly are configured to sequentially grip and release a cable. The first gripper assembly and the second gripper assembly may be configured to grip the cable simultaneously. One gripper assembly may be configured to grip the cable while the other gripper assembly releases the cable. 
     The linear winch assembly may facilitate a wide variety of cable lengths, sizes and loads which may result in improved productivity and/or efficiency. 
     The linear winch assembly may be used to winch a wide variety of cables including but not limited to lines, tether, rope, wire, wire rope, rods, umbilical, pipe, cord or conduit. 
     Preferably the first gripper assembly comprises a lid. Preferably the second gripper assembly comprises a lid. The lid may provide structural support and strength to the first and/or second gripper assembly. The lid may facilitate the gripper assembly and/or gripper block to direct a clamping force on the cable. 
     Preferably the first gripper assembly comprises a mechanism configured to open and close the lid. Preferably the second gripper assembly comprises a mechanism configured to open and close the lid. 
     The gripper block and/or lid may be configured to be moved to a position outside the winch assembly. The lid and/or gripper block may be configured to be moved to a position inside the winch assembly. 
     Preferably the linear winch assembly comprises a control unit. The control unit may be configured to control the operation of the linear winch. The control unit may be configured to control the reciprocating motion of the gripper assemblies along the longitudinal axis of the winch housing. 
     The control unit may be configured to control the laterally, vertically and/or horizontally positions of the gripper assemblies to enable controlled passing of the cable connector through the gripper assemblies. The control unit may be configured to control the position of the gripper assemblies in relation to one another to facilitate efficient winching. 
     The control unit may be configured to control the laterally, vertically and/or horizontally position of the gripper blocks and lids to control the passing of the cable connector through the gripper assemblies. 
     The control unit may be configured use feedback information relating to the position of the gripper assemblies, the positions of the cable connector and/or the stroke length of actuator to ensure that cable is winched and the cable connector is passed through the winch in the most efficient manner. 
     The control unit may be configured to monitor the position of the cable connector and/or gripper assemblies to ensure that the gripper assemblies are located in a correct position to allow the cable connector to pass in an orderly manner and mitigate cable tension, impacts and/or contact between the cable connector and the gripper assemblies. 
     Preferably the cable connector is selected from Spelter sockets, mooring sockets, wedge sockets and/or wire rope clips. 
     According to a second aspect of the invention, there is provided a linear winch assembly comprising: 
     a first gripper assembly comprising a lid and a first gripper block; 
     a second gripper assembly comprising a lid and a second gripper block; 
     a first mechanism operable to move at least part of the first gripper block out of the pathway of a cable connector to allow the connector to pass through the first gripper assembly; and 
     a second mechanism operable to move at least part of the second gripper block out of the pathway of a cable connector to allow the connector to pass through the second gripper assembly. 
     The first mechanism may be configured to move the at least part of the first gripper block laterally, vertically and/or horizontally out of the pathway of a cable connector. The first mechanism may be configured to rotate, lower, raise and/or displace at least part of the first gripper block to move out it out of the pathway of a cable connector. 
     The second mechanism may be configured to move the at least part of the second gripper block laterally, vertically and/or horizontally out of the pathway of a cable connector. The second mechanism may be configured to rotate, lower, raise and/or displace the at least part of the second gripper block to move out it out of the pathway of a cable connector. 
     The first mechanism may be configured to move at least part of the first gripper block to a position which is out of the pathway of a cable connector, wherein the position is within the housing of the linear winch assembly. 
     The second mechanism may be configured to move at least part of the second gripper block to a position which is out of the pathway of a cable connector, wherein the position is within the housing of the linear winch assembly. 
     Preferably, the first mechanism may be configured to lower at least part of the first gripper block to a position within the housing of the linear winch assembly. Preferably, the second mechanism may be configured to lower at least part of the second gripper to a position within the housing of the linear winch assembly. 
     Preferably the first gripper assembly comprises a mechanism configured to open and close the lid. Preferably the second gripper assembly comprises a mechanism configure to open and close the lid. 
     Embodiments of the second aspect of the invention may include one or more features of the first aspect of the invention or its embodiments, or vice versa. 
     According to a third aspect of the invention, there is provided a gripper assembly for a linear winch assembly comprising: 
     a lid; 
     a gripper block; and 
     a mechanism operable to move at least part of the gripper block out of the pathway of a cable connector to allow the cable connector to pass through the gripper assembly. 
     The mechanism is configured to move the at least part of gripper block in a rotary, linear and/or translational movement out of the pathway of the cable connector. 
     The mechanism may be configured to move the at least part of gripper block laterally, vertically and/or horizontally out of the pathway of the cable connector. 
     The mechanism may be configured to move the at least part of the gripper block to a position out of the pathway of a cable connector to allow the connector to pass through the gripper assembly, wherein the position is within a gripper assembly housing. 
     The mechanism may be configured to move at least part of the gripper block between an operative position in which the gripper block is in the pathway of a cable connector and an inoperative position in which the gripper block is not in the pathway of a cable connector. 
     The inoperative position of the gripper block may be laterally, vertically and/or horizontally offset from the operative position of the gripper block. 
     The cable connector may extend radially outward from the cable to a first radial distance. The inoperative position of the gripper block may be laterally, vertically and/or horizontally offset from the operative position of the gripper block by a distance equal to or greater than the first radial distance of the cable connector to allow the cable connector to pass through the gripper assembly. 
     The lid may be movably mounted on the gripper assembly. The lid may be configured to be moved to a position out of the pathway of the cable connector. Preferably the lid is pivotally mounted on the gripper assembly. 
     The gripper block may be configured to be rotated, lowered, raised and/or displaced to a position out of the pathway of the cable connector. Preferably, the mechanism may be configured to move the at least part of the gripper block to a vertically lower position which is out of the pathway of the cable connector, wherein the lower position may be within a gripper assembly housing. 
     Preferably the gripper block is movably mounted on a guide assembly. 
     The mechanism may be configured to move the at least part of the gripper block to a position parallel to the longitudinal axis of the cable connector and/or linear winch assembly housing. The mechanism may be configured to move the at least part of the gripper block to a position perpendicular to the longitudinal axis of the cable connector and/or gripper assembly housing. 
     Embodiments of the third aspect of the invention may include one or more features of the first or second aspect of the invention or their embodiments, or vice versa 
     According to a fourth aspect of the invention, there is provided a method of operating a linear winch assembly, the method comprising: 
     providing a linear winch assembly comprising: 
     at least one gripper assembly comprising a lid and a gripper block; and 
     a mechanism operable to move at least a part of the gripper block out of the pathway of a cable connector; 
     moving at least a part of the gripper block out of the pathway of a cable connector; 
     and passing the cable connector through the gripper assembly. 
     The method may comprise moving the at least a part of the gripper block around the cable connector to pass the cable connector through the gripper assembly. The method may comprise moving the at least one gripper assembly to pass the cable connector through the gripper assembly. 
     The method may comprise pulling in or paying out the cable to pass the cable connector through the gripper assembly. The method may comprise providing a second gripper assembly configured to pull in or pay out a cable. A second gripper assembly may be provided and may be configured to pull the cable and cable connector through the first gripper assembly. 
     The method may comprise moving the at least part of the gripper block laterally, vertically and/or horizontally out of the pathway of a cable connector. 
     The method may comprise: 
     providing a second gripper assembly comprising: 
     a second lid; 
     a second gripper block; and 
     a second mechanism operable to move at least a part of the second gripper block out of the pathway of a cable connector to allow the connector to pass through the second gripper block; 
     moving at least a part of the second gripper block out of the way of a cable connector; 
     pulling in or paying out a cable; and 
     passing the cable connector through the second gripper assembly. 
     Embodiments of the fourth aspect of the invention may include one or more features of the first to third aspects of the invention or their embodiments, or vice versa. 
     According to a fifth aspect of the invention, there is provided a method of operating a linear winch assembly comprising the steps of: 
     providing a linear winch assembly comprising: 
     a first gripper assembly comprising: 
     a lid; 
     a first gripper block and 
     a first mechanism operable to move at least a part of the first gripper block from an operative position in which the first gripper block is in the pathway of a cable connector to an inoperative position in which the first gripper block is not in the pathway of a cable connector; 
     moving at least a part of the first gripper block from the operative to the inoperative position; and 
     passing the cable connector through the first gripper assembly. 
     The method may comprise moving the first gripper block around the cable connector to pass the cable connector through the gripper block. 
     The method may comprise moving the at least part of the first gripper block laterally, vertically and/or horizontally out of the pathway of the cable connector. 
     The inoperative position of the first gripper block may be laterally, vertically and/or horizontally offset from the operative position of the first gripper block. 
     The method may comprise pulling in or paying out the cable to pass the cable connector through the gripper assembly. 
     The method may comprise moving the at least part of the first gripper block from an inoperative position to the operative position when the cable connector has passed through the gripper assembly. 
     The method may comprise providing: 
     a second gripper assembly comprising a lid; 
     a second gripper block and 
     a second mechanism operable to move at least a part of the second gripper block from an operative position in which the second gripper block is in the pathway of a cable connector to an inoperative position in which the second gripper block is not in the pathway of a cable connector; 
     moving at least a part of the second gripper block from the operative to the inoperative position; and 
     passing the cable connector through the second gripper assembly. 
     The method may comprise moving the at least part of the second gripper block from the inoperative position to the operative position when the cable connector has passed through the second gripper assembly. 
     The method may comprise moving the at least part of the first and/or second gripper block laterally, vertically and/or horizontally out of the pathway of the cable connector. 
     The method may comprise moving the second gripper block around the cable connector to pass the cable connector through the second gripper block. 
     The method may comprise the step of moving the at least part of the first and/or second gripper assembly to pull in or pay out a cable. 
     The method may comprise rotating, lowering, raising and/or displacing at least part of the first and/or second gripper blocks to move out it out of the pathway of a cable connector. 
     Embodiments of the fifth aspect of the invention may include one or more features of the first to fourth aspects of the invention or their embodiments, or vice versa 
     According to a sixth aspect of the invention, there is provided a method of operating a gripper assembly comprising the steps of: 
     providing a gripper assembly comprising a lid; 
     a gripper block; and 
     a mechanism operable to move at least part of the gripper block; 
     moving at least part of the gripper block out of the pathway of a cable connector; and 
     passing the cable connector through the gripper assembly. 
     The method may comprise actuating the mechanism to move the gripper block out of the pathway of a cable connector. 
     The method may comprise moving the at least part of the gripper block laterally, vertically and/or horizontally out of the pathway of the cable connector. 
     The method may comprise moving the lid out of the pathway of the cable connector. 
     Embodiments of the sixth aspect of the invention may include one or more features of the first to fifth aspects of the invention or their embodiments, or vice versa. 
     According to a seventh aspect of the invention, there is provided a method of operating a linear winch assembly, the method comprising: 
     providing a linear winch assembly comprising: 
     a first gripper assembly comprising a first lid and a first gripper block; 
     a first mechanism operable to move at least a part of the first gripper block; 
     a second gripper assembly comprising a second lid and a second gripper block; 
     a second mechanism operable to move at least a part of the second gripper block; 
     actuating the first mechanism to move at least a part of the first gripper block out of the pathway of a cable connector; 
     passing the cable connector through the first gripper assembly; 
     actuating the second mechanism to move at least a part of the second gripper block out of the pathway of a cable connector; and 
     passing the cable connector through the second gripper assembly. 
     The method may comprise actuating the first mechanism to move the at least part of first gripper block laterally, vertically and/or horizontally out of the pathway of the cable connector. 
     The method may comprise actuating the second mechanism to move the at least part of second gripper block laterally, vertically and/or horizontally out of the pathway of the cable connector. 
     The method may comprise pulling in or paying out the cable to pass the cable connector through the first and/or second gripper assemblies. 
     The method may comprise moving the second gripper assembly to push or pull the cable connector through the first gripper assembly. The method may comprise moving the first gripper assembly to push or pull the cable connector through the second gripper assembly. 
     The method may comprise moving the first gripper assembly to move the cable connector through the first gripper and/or first gripper assembly. The method may comprise moving the second gripper assembly to pass the cable connector through the second gripper block and/or second gripper assembly. 
     Embodiments of the seventh aspect of the invention may include one or more features of the first to sixth aspects of the invention or their embodiments, or vice versa 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       There will now be described, by way of example only, various embodiments of the invention with reference to the following drawings (like reference numerals referring to like features) in which: 
         FIGS. 1A and 1B  present a linear winch comprising two gripper assemblies in accordance with an embodiment the present invention, shown in perspective view; 
         FIGS. 2A and 2B  present gripper assembly of the linear winch of  FIG. 1B , shown in an enlarged perspective views; 
         FIGS. 3A, 3B and 3C  present enlarged plan, perspective and cross-sectional views of the gripper assembly of the linear winch of  FIG. 1B ; 
         FIGS. 4A, 4B and 4C  presents the gripper assembly of  FIG. 1B  in cross-sectional view and perspective views during stages of moving to a inoperative position with a wall of the gripper assembly removed for clarity; 
         FIGS. 5A and 5B  shows perspective views of the linear winch during stages of the cable connector passing through the gripper assembly; and 
         FIGS. 6A to 6D  show perspective views of the linear winch to provide details on the gripper assembly  14  reverting to an operative state after passage of the cable connector through the gripper assembly. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     An embodiment of the present invention is illustrated in  FIG. 1  and provides a number of advantages over prior art linear winches, specifically by providing robust and sturdy gripper assemblies, components of which are capable of being moved out of the pathway of a cable connector such as a socket so that the connector may pass through the winch. The linear winch is capable of performing a wide range of winching and tasks in a safe and time efficient manner. 
       FIGS. 1A and 1B  shows perspective views of linear winch assembly  10 . The linear winch assembly  10  has a housing  12 . One side of the winch assembly in  FIG. 1B  has been removed to improve the clarity of the drawing. The winch housing  11  can be seen to comprise a first gripper assembly  14  and a second gripper assembly  16 . The first gripper assembly  14  and a second gripper assembly  16  are slidably mounted within housing  12 . 
     Hydraulic cylinders  18  and  20  are mounted in the housing  12  and are connected to the gripper assemblies  14  and  16  respectively. The gripper assembly  14  is configured to be moved in reciprocating action along the longitudinal axis of the housing  12  by the extension and retraction of hydraulic cylinder  18 . The gripper assembly  16  is configured to be moved in reciprocating action along the longitudinal axis of the housing  12  by the extension and retraction of hydraulic cylinder  20 . 
     The gripper assemblies  14  and  16  are designed to engage and grip a cable  17 . The hydraulic cylinders  18  and  20  are configured to move the gripper assemblies and the gripped cable  17  along the longitudinal axis of the linear winch assembly. 
       FIG. 1B  shows hydraulic cylinder  18  in a fully extended position and hydraulic cylinder  20  in a fully retracted position. A connector socket  19  is used to connect two sections of cable  17   a  and  17   b . The socket  19  is shown in  FIG. 1B  positioned close to the gripper assembly  14  but is unable to pass though the gripper assembly  14  as there is not sufficient clearance to allow the socket  19  to pass through gripper assembly  14 . 
       FIGS. 2A and 2B  shows an enlarged perspective view of the gripper assembly  14 . The gripper assembly  14  comprises a gripper housing  24  having a base  24   a  and four walls  24   b ,  24   c ,  24   d  and  24   e . Wall  24   e  has been removed from  FIG. 2  to improve the clarity of the drawing. The walls  24   b  and  24   d  are perpendicular to the longitudinal axis of the winch assembly and have slots  26  which are dimensioned to allow a cable  17  and socket  19  to pass through the walls  24   b  and  24   d.    
     Hydraulic cylinder  18  is connected at one end to the wall  24   b  of the gripper housing  24  and is configured to slidably move the gripper housing  24  along the longitudinal axis of the winch housing  12 . 
     The gripper housing  24  comprises a lid section  28   a  and a gripper block  28   b . The lid section  28   a  is slidably mounted on the gripper block  28   b . Hydraulic cylinders  21  and  23  are connected to the gripper block  28   b  and are configured to engage with lid members  29  to slide the lid section  28   a  relative to the gripper block  28   b  along the longitudinal axis of the housing  12  by the extension and retraction of hydraulic cylinders  21  and  23 . The lid section  28   a  is configured to be slidably moved between a locked position shown in  FIG. 2A  and an unlocked position shown in  FIG. 2B . 
     The lid section  28   a  is pivotally and slidably mounted on the gripper housing  24  via a rod  34  which is connected to the walls of the gripper housing  24 . A hydraulic cylinder  36  is connected to rod  34  via a coupling  37 . The rod  34  has a hexagonal cross-section. The hydraulic cylinder  36  and coupling  37  are configured to engage rod  34  to pivotally move the lid section  28   a  between open and closed positions. Although, this example shows a hexagonal cross-section rod and hydraulic cylinder to pivotally move the lid section between open and closed positions it will also be clear that other rod cross sections and/or other mechanisms may be used. 
     The gripper block  28   b  is movably mounted on guide rails  30  via guide wheels  31  mounted on a base section of the gripper block  28   b . Hydraulic cylinders  32  and  33  are connected at one end to the gripper block  28   b  and to the base  24   a  of the gripper housing  24  at the other end. The hydraulic cylinders  32  and  33  are configured to move the gripper block  28   b  along the sloped pathway of the guide rails  30 . By moving the guide wheels  31  of the gripper block  28   b  along the sloped pathway of the guide rails  30  the gripper block  28   b  is lowered out of the pathway of the cable  17  and/or socket  19 . 
     Although, this example shows guide rails  30  and guide wheels  31  are used to lower the gripper block  28   b  out of the pathway of the cable  17  and socket  19  other guide arrangements and/or mechanisms may be used. It will also be clear that other assembly components may be moved in other directions to move the assembly out of the pathway of the cable  17  and socket  19 . 
     The lid section  28   a  and gripper block  28   b  have a wedge shape. The dimensions of the lid section  28   a  and gripper block  28   b  are such that when the wedge shape lid section  28   a  is positioned on top of the corresponding wedge shape gripper block  28   b  and moved by the actuation of hydraulic cylinders  21  and  23  in a general direction Y along the longitudinal axis of the housing  12 , the inner surfaces of the wedged shape lid section  28   a  bears against the outer surfaces of the wedged shape gripper block  28   b . In this position the lid is clamped onto the gripper block  28   b .  FIG. 2A  shows the lid section  28   a  in a clamped position. 
     However, actuation of hydraulic cylinders  21  and  23  to move lid section  28   a  in a general direction Z along the longitudinal axis of the housing  12  causes the inner surfaces of the wedged shape lid section  28   a  to move away from the outer surfaces of the wedged shape gripper block  28   b . In this position the lid is released from the gripper block  28   b .  FIG. 2B  shows the lid section  28   a  in a released position. 
       FIGS. 3A, 3B and 3C  show an enlarged plan, perspective and cross-sectional views of the gripper assembly  14 . The lid section  28   a  has been removed for clarity. The gripper block  28   b  comprises two parallel bearing members  42  mounted on the gripper block  28   b  in a generally wedged shape. The gripper block  28   b  comprises a gripper slider  44  which houses two clamp members  46 . 
     The clamp members  46  have inner faces  46   a  which have longitudinal semi-cylindrical grooves  46   b  that are dimensioned to receive the cable  17 . The size and shape of the semi-cylindrical grooves  46   b  may be changed for different cable sizes and/or types. 
     The gripper block  28   b  is configured to restrain and grip the cable  17  and pull the cable in a first direction as shown by arrow Y in  FIG. 3A  and to release the cable and allow the cable to move freely relative to the gripper block in the opposite direction of travel represented by arrow Z in  FIG. 3A . 
     The outer surfaces  46   c  of the clamp members  46  have a wedge shape. The clamp members  46  are configured to move perpendicular to the longitudinal axis of the housing  12  to bear against bearing members  42  when the gripper block  28   b  is moved in a general direction Y. When the movable clamp members are moved in the direction Y, they transmit a force to the bearing members  42 . The bearing members  42  are fixed in the base section of the gripper block  28   b  which causes a reaction force against the inner surfaces of the clamp members  46  to clamp on to and grip the cable  17 . 
     When the gripper block  28   b  is moved in a direction shown by arrow Z in  FIG. 3A , clamp members  46  move away from the wedge bearing members  42 . The reaction force acting against the clamp members  46  by the bearing members  42  is reduced. The inner surfaces of the clamp members  44  are moved away from the cable  17 . The cable is free to move within the clamp members  46  and the gripper assembly  14 . 
       FIG. 3C  shows a hydraulic cylinder  45  connected at one end to the base section of the gripper block  28   b  and to gripper slider  44  at the other end. The gripper slider  44  is configured to be moved between a cable engaged position as shown in  FIG. 3B  and a cable release position as shown in  FIG. 4A . 
     In the cable engaged position as shown in  FIG. 3B  the gripper slider is located in the gripper block  28   b  between the bearing members  42 . The clamp members  46  are moved toward one another to engage the cable in the longitudinal semi-cylindrical grooves  46   b.    
     In the cable release position as shown in  FIG. 4A  the gripper slider  44  is located partially outside the gripper block  28   b . The clamp members  46  are moved away from one another to allow the cable to be removed from the longitudinal semi-cylindrical grooves  46   b.    
       FIG. 4A to 4C  presents the gripper assembly during stages of socket passing in cross-sectional view and perspective views with a wall of the gripper assembly removed for clarity. 
     The hydraulic cylinder  45  (shown in  FIG. 3C ) is actuated to move the gripper slider  44  from a cable engaged position to a cable release position as shown in  FIG. 4A . The gripper slider  44  is located partially outside the gripper block  28   b . The clamp members  46  are moved away from one another to allow the cable to be removed from the longitudinal semi-cylindrical grooves  46   b.    
     The gripper assembly comprises guide rails  30 . Each guide rail  30  comprises a first part  30   a  which positions the gripper block  28   b  at an operative position in which the gripper block is in the pathway of the cable connector at an elevated position above the base  24   a  of the gripper assembly  14 . Each guide rail  30  comprises a second part  30   b  provides a sloped guide path; and a third part  30   c  which positions the gripper block  28   b  at an inoperative position in which the gripper block is not in the pathway of a cable connector and is close to the base  24   a  of the gripper assembly  14 . 
     Upper guide rails  31  are located above the first part  30   a  of guide rail  30  and partially along second part  30   b  to ensure that the gripper block  28   b  is accurately positioned in the operative position. 
     The operative position of the gripper block  28   b  may be defined as the position that the gripper block  28   b  is located during normal winching of the cable by the gripper assembly  14 . The inoperative position of the gripper block  28   b  may be defined as the position wherein the gripper block  28   b  is located at the third part  30   c  of guide rail  30  out of the pathway of the socket  19  to allow socket  19  to pass through the gripper assembly  14 . 
     The operative position of the lid section  28   a  may be defined as the position that the lid section  28   a  is located during normal winching of the cable by the gripper assembly  14 . The inoperative position of the lid section  28   a  may be defined as the position wherein the lid section  28   a  is moved to an open position. 
     Guide rails  30  are configured to receive wheels which are connected to the base section of the gripper block  28   b  as shown in  FIG. 4A . Hydraulic cylinders  32  and  33  are actuated to pull the gripper block  28   b  along guide rails  30 . This action lowers the gripper block away from the lid section. The hydraulic cylinders  32  and  33  are configured to position the gripper block at the third part  30   c  of guide rail  30  when the cylinders are at their fully retracted position as shown in  FIG. 4B . At this lower position the gripper block  28   b  is moved out of the pathway of the socket  19 . 
     Hydraulic cylinder  36  is actuated to pivot the lid section  28   a  between a closed position and an open position.  FIG. 4C  shows the gripper assembly  14  in a socket pass position. In the socket pass position the gripper block  28   b  is located at the third part  30   c  of guide rail and the lid section  28   a  is pivoted to an open position. The gripper block  28   b  and lid section  28   a  have been moved out of the pathway of the cable socket  19 . The socket now has sufficient clearance to pass though the gripper assembly  14 . 
     Although this example describes the gripper block being moved vertically out of the pathway of the cable connector. It will be clear that alternatively the gripper block may be moved in laterally, horizontally and/or vertically out of the pathway of the cable connector. 
       FIGS. 5A and 5B  shows perspective views of the linear winch with the gripper assembly  14  in an inoperative socket pass configuration to provide details on the movement of the socket through the gripper assembly  14 . The hydraulic cylinder  18  is actuated to a retracted position to move the gripper assembly  14  in a direction shown as arrow Z in  FIG. 5A  to move the gripper assembly around the socket  19 . The socket  19  is able to pass through the slot  26  in the gripper assembly  14 . The inoperative state of the gripper assembly provides clearance for the socket  19 . The retraction of hydraulic cylinder  18  moves the gripper assembly  14  such that the socket is positioned within the gripper assembly  14 . In order to fully pass the socket through the gripper assembly  14  the cable and socket is pulled by the second gripper assembly  16 . 
     Hydraulic cylinder  20  is actuated to an extended position to move the gripper assembly  16  in a direction shown as arrow Y in  FIG. 5B . The cable  17  and socket  19  are pulled through the gripper assembly  14  in the inoperative state. 
     Hydraulic cylinder  18  may be dimensioned such that its stroke length is sufficient to move the gripper assembly  14  around the socket  19  so that the socket completely passed through the gripper assembly  14 . 
       FIGS. 6A to 6D  show perspective views of the linear winch to provide details on how the gripper assembly  14  reverts to an operative state after passage of the socket through the gripper assembly  14 . 
       FIG. 6A  shows the gripper block  28   b  located in an inoperative position where the gripper block  28   b  is located at the third part  30   c  of guide rail  30 . Hydraulic cylinder  36  is actuated to a retracted position to rotate the rod  34  and pivot the lid section  28   a  from a generally vertical open position to a generally closed horizontal position. The lid section  28   a  in the closed position is supported by tabs  71  on wall  24   e  of the gripper assembly housing  24 . Although in  FIG. 6A  wall  24   e  is removed for clarity, the location of tabs  71  is shown. 
     Hydraulic cylinders  32  and  33  are actuated to push the gripper block  28   b  along guide rails  30  from the third part  30   c  along the second part  30   b  to a first part  30   a  which positions the gripper block  28   b  at an operative position which is parallel with the longitudinal axis of in the housing  12  at an elevated position above the base  24   a  of the gripper assembly  14 . 
     As the gripper block  28   b  is moved from an inoperative position to an operative position the gripper slider  44  is located in the cable release position where the gripper slider  44  is located partially outside the gripper block  28   b . The clamp members  46  are spaced apart from one another to allow the clamp members  46  to be positioned around cable  17  such that the cable  17  is located within the longitudinal semi-cylindrical groove  46   b.    
     In this operative position shown in  FIG. 6B , the upper part of the gripper block  28   b  is surrounded by the lid section. The lid is in an unlocked position. 
     The hydraulic cylinder  45  is actuated to move the gripper slider  44  from a cable released position to a cable engaged position where the gripper slider  44  is positioned between the bearing members  42  as shown in  FIG. 6B . The clamp members are moved toward one another to engage the cable in the longitudinal semi-cylindrical grooves  46   b.    
       FIG. 6D  shows the actuation of hydraulic cylinders  21  and  23  in a general direction Y along the longitudinal axis of the housing  12  to move the lid section  28   a  from an unlocked position to a locked position. In the unlocked position the wedged shape lid section  28   a  is positioned on top of the corresponding wedged shape gripper block  28   b . The inner surfaces of the wedged shape lid section  28   a  do not bear against the outer surfaces of the wedged shape gripper block  28   b.    
     The actuation of hydraulic cylinders  21  and  23  in a general direction Y moves the lid section  28   b  to a locked position such that the inner surfaces of the wedged shape lid section  28   a  bears against the outer surfaces of the wedged shape gripper block  28   b . In this locked position the lid is clamped onto the gripper block  28   b . In the locked position the lid provides structural support to the gripper block and may facilitate the gripper block to direct its clamping force to the cable. 
       FIG. 6D  shows the gripper assembly in an operative position where actuation of the hydraulic cylinder  18  to move the gripper assembly  14  in a direction shown by arrow Y results in the gripper assembly  14  gripping the cable and moving the cable in a direction Y. If the hydraulic cylinder  18  moves the gripper assembly  14  in a direction shown by arrow Z the gripper assembly in an operative position direction Y allows the cable to move freely within the gripper assembly. 
     The gripper assembly  14  is operable to move between an operative position and inoperative position. In the operative position the gripper assembly is configured to grip and release the cable. In the inoperative position the gripper assembly is configured to be moved out of the pathway of the cable socket. 
     In order to pass the socket  19  through the gripper assembly  14 , the gripper block  28   b  releases the cable and moves to an inoperative position to provide a pathway for the socket  19  to pass through the gripper assembly  14 . When the gripper assembly  14  is positioned in the inoperative position, the gripper assembly  16  is positioned in an operative position to grip, hold, pull and/or push the cable. The gripper assembly  16  is configured to maintain the tension of the cable when the gripper assembly  14  is positioned in an inoperative position. The gripper assembly  16  is configured to moves the cable along the longitudinal axis of the winch assembly to facilitates the passing of the socket  19  through the gripper assembly  14 . 
     The actions of passing the socket  19  through the gripper assembly  16  are the same as the above described method of passing the socket through the gripper assembly  14 . The gripper assembly  14  is maintained in an operative position during the passing of the socket through the gripper assembly  16  to hold, pull and/or push the cable. The gripper assembly  14  is configured to maintain the tension of the cable  17  when the gripper block of the gripper assembly  16  is positioned in an inoperative position to allow the socket to pass. The gripper assembly  14  is configured to move the cable  17  along the longitudinal axis of the winch assembly which facilitates the passing of the socket  19  through the gripper assembly  16 . 
     Although this example describes two gripper assemblies  14  and  16  in the winch to pull the cable  17 , additional gripper assemblies may be used in combination to provide additional pulling and/or pushing force when winching heavy loads. 
     Although this example describes a single hydraulic cylinders connected to each of the gripper assemblies  14  and  16 , additional hydraulic cylinders may be connected between the housing  12  and each gripper assembly which may be used in combination with the hydraulic cylinders  18  and  20  to provide additional pulling and/or pushing force when winching heavy loads. 
     Although, this example shows the lid section  28   a  being pivoted to an open position before the socket is able to pass through the gripper assembly  14 , it will be clear that the gripper block  28   b  and the lid section  28   a  may be dimensioned or arranged such that the socket may pass through the gripper assembly when the lid section  28   a  is in a closed position and the gripper block  28   b  is in an inoperative position. 
     Throughout the specification, unless the context demands otherwise, the terms ‘comprise’ or ‘include’, or variations such as ‘comprises’ or ‘comprising’, ‘includes’ or ‘including’ will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers. Furthermore, relative terms such as, “horizontal”, “vertical”, raise, lower and the like are used herein to indicate directions and locations as they apply to the appended drawings and will not be construed as limiting the invention and features thereof to particular arrangements or orientations. 
     The foregoing description of the invention has been presented for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed. The described embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilise the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Therefore, further modifications or improvements may be incorporated without departing from the scope of the invention as defined by the appended claims. 
     The invention provides a linear winch assembly, gripper assembly and a method of use. The linear winch assembly comprises a first gripper assembly comprising a first gripper block operable to grip a cable and a second gripper assembly comprising a second gripper block operable to grip a cable. The winch assembly comprises a first mechanism operable to move at least part of the first gripper block out of the pathway of a cable connector to allow the connector to pass through the first gripper assembly. The winch assembly also comprises a second mechanism operable to move at least part of the second gripper block out of the pathway of a cable connector to allow the connector to pass through the second gripper assembly 
     The sequential passing of the cable connector through each gripper assembly allows the winch assembly to maintain the cable tension. The first gripper assembly may be moved to an inoperative position out of the pathway of the socket while the second assembly maintains the cable tension and applied a pulling force to the cable. The second gripper assembly may subsequently be moved to an inoperative position out of the pathway of the cable connector while the first gripper assembly maintains the cable tension and applied a pulling force to the cable. 
     The linear winch assembly is able to perform tasks involving pulling in or paying out long cables with cable socket connections. The assembly is capable of passing the cable connector while maintaining cable tension from heavy loads. 
     Another benefit of the improved gripper assembly is that it may improve the performance of the winch assembly by facilitating the passage of a cable connector quickly and safely through the gripper assembly without having to use a crane or lifting equipment. 
     Various modifications to the above described embodiments may be made within the scope of the invention herein intended.