Abstract:
A cable puller and associated methods are shown. Useful example methods include pipe bursting using cable pullers as shown. Cable pullers and methods shown provide a mechanical advantage that increases an amount of cable pulled in one cycle. Selected examples are shown that include a pulley located on a distal end of a moving portion of an extending and contracting beam. The pulley and the mechanical advantage it supplies helps to improve the efficiency of the cable puller and reduce manufacturing cost of the cable puller.

Description:
CLAIM OF PRIORITY 
       [0001]    This application claims the benefit of priority to U.S. Provisional Application Ser. No. 62/233,875, filed on Sep. 28, 2015, the contents of which are incorporated by reference herein in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    Embodiments described herein generally relate to cable pulling. Specific examples may include pipe bursting or pipe splitting using cyclic cable pullers. 
       BACKGROUND 
       [0003]    Trenchless pipe replacement is useful for replacement of pipes or other buried conduits without the need to excavate the length of pipe to be replaced. An example of trenchless pipe replacement includes pulling a cutting blade with an expander through the pipe to be replaced, and attaching a new pipe behind the cutting blade. The pipe to be replaced is split, and pushed into the surrounding soil, and the new pipe, of equal or larger diameter, is pulled into the new space within the split pipe. Splitters are commonly used for small diameter pipes, and for pipes of a material that lends itself to splitting. Another example of trenchless pipe replacement includes pipe bursting. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is a perspective view of a cable puller in accordance with some embodiments of the invention. 
           [0005]      FIG. 2A  is a side view of a gripping device in accordance with some embodiments of the invention. 
           [0006]      FIG. 2B  is another side view of the gripping device from  FIG. 2A  in accordance with some embodiments of the invention. 
           [0007]      FIG. 3A  is a perspective view of a splitter in accordance with some embodiments of the invention. 
           [0008]      FIG. 3B  is another perspective view of the splitter from  FIG. 3A  in accordance with some embodiments of the invention. 
           [0009]      FIG. 3C  is cross section diagram view of the splitter from  FIGS. 3A and 3B  in accordance with some embodiments of the invention. 
           [0010]      FIG. 4  is an end view of a portion of a cable puller in accordance with some embodiments of the invention. 
           [0011]      FIG. 5  is a side view of a cable puller in use in accordance with some embodiments of the invention. 
           [0012]      FIG. 6  is a flow diagram of a method of operating a cable puller in accordance with some embodiments of the invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0013]    The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims. 
         [0014]      FIG. 1  shows a cable puller  100  according to an example of the invention. An extending and contracting beam  110  is shown, including a stationary portion  112  and a moving portion  114 . In one example, the extending and contracting beam  110  includes a hydraulic cylinder. In one example, the extending and contracting beam  110  is composed solely of a hydraulic cylinder, and no other supporting structure is used. Although a hydraulic cylinder is used as an example, other extending and contracting devices may be used, such as an electric motor driven extender, etc. A portion of a cable  102  is shown within the cable puller  100  to aid in description of other components of the cable puller  100  and their functions. 
         [0015]    A soil reaction plate  120  is further shown coupled to an end of the extending and contracting beam  110 . In the example shown, a second soil reaction plate  122  is shown coupled at approximately 90 degrees to the soil reaction plate  120 . In one example, a pair or orthogonal reaction plates  120 ,  122  may be useful to abut against a side and a bottom of an exit pit in a pipe bursting or pipe removal application. Although two reaction plates are shown in  FIG. 1 , the invention is not so limited. Other examples may include a single reaction plate, or no reaction plate at all. In some examples a reaction plate may be a separate component from the cable puller. 
         [0016]    In the example shown, the soil reaction plate  120  includes a slot  124  the slot  124  is configured to allow the reaction plate  120  and in some examples the second reaction plate  122  to be sideways mounted onto a cable that may already be located within a pipe to be burst, with the cable  102  lying within an exit pit. In one example, the slot  124  is large enough to accept a bursting head. More details of this example are discussed in examples below with respect to  FIGS. 4 and 5 . 
         [0017]    A pulley  130  is shown coupled to an end of the extending and contracting beam  110  opposite from the reaction plate  120 , or otherwise opposite a location where a cable will exit the ground during a bursting or removal operation. In the example shown, a pair of plates  132  are included to provide improved guidance to the cable being pulled, and to protect a user from exposed rotating portions of the pulley  130 . In one example, a bolt or other retainer may be inserted or through holes  133  to further capture the cable  102  being pulled during an operation. 
         [0018]    A cable gripping device  140  is shown coupled to the stationary portion  114  of the extending and contracting beam  110 . More details of the cable gripping device  140  are discussed below with respect to  FIGS. 2A and 2B . In one example, a guide pulley  148  is located adjacent to the cable gripping device  140 . The guide pulley  148  may be used to pull a loose end easily away from the cable puller  100  as the cable  102  exits the cable puller  100 . An operator may stand at a distance of a number of feet away from the cable puller  100 , and the guide pulley  148  easily keeps the loose cable  102  from becoming tangled as the cable puller  100  cycles through a number of strokes. 
         [0019]    In operation, the moving end  114  of the extending and contracting beam  110  is cycled back and forth to pull the cable  102  in a series of strokes. The cable gripping device  140  engages and releases the cable  102  between successive strokes of the extending and contracting beam  110 . The pulley  130  provides a mechanical advantage to the extending and contracting beam  110 . Specifically, because the extending and contracting beam  110  lengthens a portion of cable  102  on both sides of the extending and contracting beam  110  the mechanical advantage of the pulley doubles an amount of cable pulled in one cycle. 
         [0020]    This can be useful in cable pulling, especially over long distance pulls. If an amount of cable pulled in a single cycle is too short, the cable may merely stretch out and spring back in each cycle, and a bursting or splitting head may not move within the pipe to be burst at all. By using a heavier rated hydraulic cylinder, and doubling the amount of cable pulled for each stroke, the above detailed problem is avoided entirely, or greatly reduced. 
         [0021]    Some cyclic cable pulling systems have employed the use of both a pulling cable gripping device, and a holding cable gripping device to hold the cable in tension while the pulling cable gripping device cycles back for another stroke. By using configurations of the present invention, an amount of cable pulled for each stroke is doubled. As a result, in some examples, only a single cable gripping device is needed, because some amount of cable stretch can be accommodated with such a long amount of cable being pulled for each stroke. 
         [0022]    Using only one cable gripping device simplifies the cable puller  100  and reduces the cost of the machine. By doubling the amount of cable pulled for each stroke, a bursting operation can performed much faster than with a shorter stroke cyclic puller. 
         [0023]    In one example, a splitter  150  is attached to the stationary portion before the cable gripper. More details of the splitter  150  are discussed below with respect to  FIGS. 3A-3C . 
         [0024]    In one example, a pivot  162  is included to allow the extending and contracting beam  110  to be oriented within a range of angles with respect to the soil reaction plate  120 . In one example, the pivot  162  works in conjunction with a number of selector holes  170  and pins (not shown). 
         [0025]      FIGS. 2A and 2B  show close up views of an example of a cable gripping device  140 . A first jaw  142  and a second jaw  144  are located opposite one another, with a linkage mechanism  141  to apply a gripping force to a cable. In one example, the linkage mechanism  141  is actuated by friction in the cable, which pulls the second jaw  144  tight onto the cable, In one example, a release trigger  146  is included on a portion of the cable puller  100 , and positioned to bump into the second jaw  144  at the end of a contracting stroke of the extending and contracting beam  110 . In this way, the cable will be released, and the slack may be pulled tight by an operator, who may pull the slack cable over the guide puller  148 , and away from the cable puller  100 . 
         [0026]      FIG. 2A  shows a pair of plates  145  that may be included in select examples to protect from moving parts of the cable gripping device  140  during operation. In one example the cable gripping device  140  may be configured to be capable of side loading. A space  143  is located between the first jaw  142  and a side plate  145 . In use, an operator may insert a side surface of a cable into the space  143 , and then laterally between the first jaw  142  and the second jaw  144 . In many cases, it is convenient to be able to side load a cable onto the cable puller  100  and into the cable gripping device  140 . As discussed above, cables may be first pulled through a pipe to be replaced, and the cable puller  100  may be dropped into an exit it after the cable is already there. In such a case, it is desirable to be able to side load a cable into one or more components of the cable puller  100 . 
         [0027]      FIGS. 3A-3C  show an example of a splitter that may be included in one embodiment of the invention.  FIG. 3A  shows a splitter base  152  and a pulley  154  located opposite the splitter base  152 . A pair of side plates  156  are included to hold the pulley  154  in place. 
         [0028]    In an operation such as pipe bursting or splitting, a pipe that is being burst may instead start to be pulled out of the ground with the cable still located inside the pipe. This may be undesirable, as the pipe may foul up the working of components of the cable puller  100  such as the pulley  130  or the cable gripping device  140 . 
         [0029]      FIG. 3B  shows a blade  158  that is located in the path of a pipe that may be undesirably pulled out of the ground. The blade  158  splits the pipe as it is pulled into the cable puller  100 , and the spit pipe may be more easily removed from the cable puller  100  before it fouls up any downstream components. In the example shown, the blade  258  is a stationary blade, however, other examples such as a wheel cutter may be used. 
         [0030]    In one example, the blade  158  is replaceable, such as if the blade  158  becomes worn. In the example shown, the blade  158  is formed on a base that slides down into a slot in the splitter base  152 . In one example, the blade  158  is held in place in the slot by one or more spring loaded balls that correspond to a detent.  FIG. 3C  shows a ball  155  being biased by a spring  153 . The ball  155  is thereby urged into a detent  157  on the base of the blade  158 . In one example, if a blade  158  is to be replaced, a screwdriver or other tool may be wedged from underneath the blade  158  or the splitter base  152  to dislodge the ball  155  from the detent  157 . In other examples, the blade  158  may be gripped with pliers and pulled out with force sufficient to overcome the ball  155  and detent  157 . Although a replaceable blade  158  is shown, other example of splitters  150  may not include replaceable blades  158 . 
         [0031]      FIG. 4  shows a front view of the soil reaction plate  120 . A pulley  160  is shown attached to the stationary portion  112  adjacent to the soil reaction plate  120 . In the example shown, the pulley  160  includes an inner groove  164  sized for a cable to be pulled, and an outer surface  166  to guide a bursting head  200  around the pulley  160 . In the example shown, the soil reaction plate  120  includes a slot  124  large enough to accept a bursting head  200 . 
         [0032]    In operation, it is difficult to remove a bursting head from an end of the new pipe that is being pulled into the soil after the old pipe is burst or split. It is much easier to remove the bursting head from the end of the new pipe, if the bursting head is pulled a larger distance into the exit pit before ending the pull. By having a slot  124  large enough to accept a bursting head  200 , and an outer surface  166  to guide a bursting head  200  around the pulley  160 , the bursting head can be pulled past the soil reaction plate  120 , and further into the exit pit, to better facilitate the removal of the bursting head, and still have a large amount of new pipe extending into the exit pit with which to work on. 
         [0033]      FIG. 5  shows a diagram view of an example operation using a cable puller  100  as described in examples above. An entry pit  402  and an exit pit  404  are shown. A pipe to be replaced  410  is shown, and a new pipe  210  is being pulled in to replace the pipe to be replaced  410 . A bursting head  200  is shown coupled to a cable  420  and to the new pipe  210 . 
         [0034]    An example of a cable puller  100  is shown located in the exit pit  404 . As described above, the extending and contracting beam  110  moves as indicated by arrows  430 , and pulls the cable  420  over the pulley  130  at the top of the extending and contracting beam  110 . As described above, a first portion of cable  422  and a second portion of cable  424  are both lengthened by the motion  430  of the pulley  130  and the extending and contracting beam  110 . This feature doubles the amount of cable pulled in each stroke. A loose end  426  of the cable may be pulled out of the way of the cable puller  100  by a user between cycles. 
         [0035]      FIG. 6  shows one example method of operating a cable puller as shown in  FIG. 5 . In operation  602 , a cable is placed through a pipe to be replaced having a bursting head attached to a distal end of the cable. In operation  604 , the cable is routed around a pulley attached at a distal, moving end of an extending and contracting beam. In operation  606 , the cable is gripped on a stationary portion of the extending and contracting beam, and in operation  608 . the moving end of the extending and contracting beam is extended. The mechanical advantage of the pulley is used to double an amount of cable pulled in an extension of the extending and contracting beam. 
         [0036]    To better illustrate the method and apparatuses disclosed herein, a non-limiting list of examples is provided here: 
         [0037]    Example 1 includes cable puller, including an extending and contracting beam, including a stationary portion and a moving portion, a soil reaction plate coupled to the stationary portion, a pulley attached at a distal end of the moving portion, and a cable gripping device attached to the stationary portion. 
         [0038]    Example 2 includes the cable puller of example 1, wherein the extending and contracting beam includes a hydraulic cylinder to power the extending and contracting beam. 
         [0039]    Example 3 includes the cable puller of any one of examples 1-2, wherein the extending and contracting beam is a hydraulic cylinder. 
         [0040]    Example 4 includes the cable puller of any one of examples 1-3, further including a guide pulley located adjacent to the cable gripping device. 
         [0041]    Example 5 includes the cable puller of any one of examples 1-4, wherein the soil reaction plate includes a slot large enough to accept a bursting head. 
         [0042]    Example 6 includes the cable puller of any one of examples 1-5, wherein the soil reaction plate includes a vertical and horizontal reaction plate portion. 
         [0043]    Example 7 includes the cable puller of any one of examples 1-6, wherein the cable gripper is capable of side loading. 
         [0044]    Example 8 includes the cable puller of any one of examples 1-7, further including a splitter attached to the stationary portion before the cable gripper. 
         [0045]    Example 9 includes the cable puller of any one of examples 1-8, wherein the splitter includes a stationary blade that is replaceable. 
         [0046]    Example 10 includes the cable puller of any one of examples 1-9, wherein the stationary blade is held in place with one or more spring loaded balls that correspond to a detent. 
         [0047]    Example 11 includes 1 cable puller including an extending and contracting beam, including a stationary portion and a moving portion, a soil reaction plate coupled to the stationary portion, a first pulley attached to the stationary portion adjacent to the soil reaction plate, a second pulley attached at a distal end of the moving portion, and a cable gripping device attached to the stationary portion. 
         [0048]    Example 12 includes the cable puller of example 11, further including an actuator to disengage the cable gripping device during a cycle of the extending and contracting beam. 
         [0049]    Example 13 includes the cable puller of any one of examples 11-12, wherein the extending and contracting beam is a hydraulic cylinder. 
         [0050]    Example 14 includes the cable puller of any one of examples 11-13, wherein abeam angle with respect to the soil reaction plate is adjustable. 
         [0051]    Example 15 includes the cable puller of any one of examples 11-14, wherein the first pulley includes an inner groove sized for a cable to be pulled, and an outer surface to guide a bursting head around the first pulley. 
         [0052]    Example 16 includes the cable puller of any one of examples 11-15, wherein the soil reaction plate includes a slot large enough to accept a bursting head. 
         [0053]    Example 17 includes a method, including placing a cable through a pipe to be replaced having a bursting head attached to a distal end of the cable, routing the cable around a pulley attached at a distal, moving end of an extending and contracting beam, gripping the cable on a stationary portion of the extending and contracting beam, and extending the moving end of the extending and contracting beam and using the mechanical advantage of the pulley to double an amount of cable pulled in an extension of the extending and contracting beam. 
         [0054]    Example 18 include the method of example 17, further including routing the cable around a stationary pulley located on the stationary portion of the extending and contracting beam and pulling the cable at an angle upwards out of an exit pit. 
         [0055]    Example 19 includes the method of any one of examples 17-18, further including pulling the bursting head out of the ground at an end of a run, and through an opening in a reaction plate. 
         [0056]    Example 20 includes the method of any one of examples 17-19, wherein pulling the bursting head out of the ground at an end of a run includes pulling the bursting head through the opening in the reaction plate and around at least a portion of the stationary pulley. 
         [0057]    The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples.” Such examples can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples or one or more aspects thereof) shown or described herein. 
         [0058]    In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B hut not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. 
         [0059]    The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.