Abstract:
A pipe puller apparatus includes a body and a main actuator mounted on the body. A strut assembly is also mounted on the body and includes a first shoe and a second shoe. The first shoe is adapted to engage a first interior wall of a pipe and the second shoe is adapted to engage a second interior wall of the pipe. The strut assembly includes a strut actuator that is adapted to increase the distance between the first shoe and the second shoe.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/928,274, filed Jan. 16, 2014, the disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates in general to an apparatus for pulling a first pipe into contact with a stationary second pipe, and more particularly to an improved apparatus for pulling a first pipe into contact with a stationary second pipe. 
         [0003]    Large pipes are often installed in situations in which it is desired to provide a path for water to flow where it is not desirable to have an open channel. For example, a sewer may be installed below grade in a location where a road will pass over the sewer. Large pipes may be sections of precast, concrete pipe that are abutted end-to-end to provide the desired total length of channel. Each individual section of pipe is typically pulled against a neighboring section, in order to provide an acceptable seal between the sections of pipe. 
         [0004]    Known apparatus for pulling pipe can be large, extremely heavy, expensive, and difficult to position within a pipe. It would therefore be advantageous to provide an improved apparatus for pulling pipe that is smaller, lighter, less expensive, and easier to use than known apparatus. 
       SUMMARY OF THE INVENTION 
       [0005]    The invention relates to a pipe puller apparatus. The pipe puller apparatus includes a body and a main actuator mounted on the body. A strut assembly is also mounted on the body and includes a first shoe and a second shoe. The first shoe is adapted to engage a first interior wall of a pipe and the second shoe is adapted to engage a second interior wall of the pipe. The strut assembly includes a strut actuator that is adapted to increase the distance between the first shoe and the second shoe. 
         [0006]    Another embodiment of the invention further relates to a pipe puller apparatus that includes a strut mounted on the body for rotation about a strut axle, and a pivot plate mounted on the body for rotation about the strut axle. In this embodiment, the first shoe is mounted on the strut and the second shoe is mounted on the pivot plate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a cross-sectional side view of a first pipe section, a second pipe section, and a pipe puller. 
           [0008]      FIG. 2  is a exploded view of the pipe puller. 
           [0009]      FIG. 3  is a side view of the pipe puller, located in the first pipe section in a transport position. 
           [0010]      FIG. 4  is a view similar to that of  FIG. 3 , showing the pipe puller in an initial use position. 
           [0011]      FIG. 5  is a view similar to that of  FIG. 4 , showing the pipe puller in a set position. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0012]    This application describes an improvement to the pipe puller described in U.S. Pat. No. 6,969,217, the disclosure of which is hereby incorporated by reference. In reference to FIG. 7 of U.S. Pat. No. 6,969,217, the improvement described herein relates in part to a mechanism to release the strut  42  from its wedged position without requiring the use of the release mechanism or push-off tube assembly  74 . 
         [0013]    Referring to  FIG. 1 , there is illustrated a cross-sectional side view of a first pipe section  10  and a second pipe section  12 . The illustrated first pipe section  10  and second pipe section  12  are preformed concrete pipes, but may be any desired type of pipe. Each of the illustrated first pipe section  10  and the second pipe section  12  are cylindrical culverts having the same inner width indicated at  14 . However, it should be appreciated that the first pipe section  10  and the second pipe section  12  may have any desired shapes and dimensions. 
         [0014]    The first pipe section  10  includes a first male end  10   a  and a first female end  10   b  and defines a first longitudinal axis  10   c.  Similarly, the second pipe section  12  includes a second male end  12   a  and a second female end  12   b  and defines a second longitudinal axis  12   c.  The second pipe section  12  is disposed so that the second longitudinal axis  12   c  is generally collinear with the first longitudinal axis  10   c.  A pipe puller, indicated generally at  16 , is positioned within the first pipe section  10 . The pipe puller  16  is provided to apply a force to pull the second pipe section  12  toward the first pipe section  10  so that the second male end  12   a  engages the first female end  10   b.    
         [0015]    Referring now to  FIG. 2 , an exploded view of a portion of the pipe puller  16  is shown. The pipe puller  16  includes a body  18  that extends along a pipe puller axis  20  between a front end  22  and a rear end  24 . A wheel axle  26  extends from the body  18  perpendicularly to the pipe puller axis  20 . A pair of wheels  28  (one is visible in  FIG. 2 ) is attached to the wheel axle  26  in order to allow the assembled pipe puller  16  to be moved by rolling A frame handle  30  extends from the body  18  to be used by an operator maneuvering the pipe puller  16 . The illustrated body  18  is made of ⅜ inch plate steel, but the body  18  and other components of the pipe puller  16  may be made of any desired materials. 
         [0016]    Referring to  FIG. 3 , a side view of the assembled pipe puller  16  is shown. The wheels  26  are shown illustrated transparently, so that the other components of the pipe puller  16  are visible. The pipe puller  16  includes a strut assembly, indicated generally at  32 , that is rotatably attached to the body  18 . 
         [0017]    The strut assembly  32  includes an adjustable length strut  34 . The illustrated adjustable length strut  34  is a telescoping strut that includes an inner section slidable relative to an outer section. However, the strut  34  may be any other type of adjustable length member, or may have a fixed length, if desired. A first end  36  of the strut  34  is pivotally attached to the body  18  by a strut axle  38  that extends perpendicularly to the pipe puller axis  20  and parallel to the wheel axis  26 . A second end  40  of the strut  34  is pivotally attached to a first shoe  42 . The illustrated first shoe  42  is made of ¾ inch plate steel, but may be made of any desired material. 
         [0018]    The strut assembly  32  includes a strut actuator  44  that is pivotally connected to the strut  34  and to a pivot plate  46 . The illustrated strut actuator  44  is a hydraulic cylinder, but may be any desired force generating device. The illustrated strut actuator  44  is powered by a power unit  45 , which may be a motor, a pump, or any desired source of power to operate the strut actuator  44 . 
         [0019]    The pivot plate  46  is pivotally attached to the body  18  at an axis that coincides with the strut axle  38 . The illustrated pivot plate  46  is pivotally attached to the strut axle  38 , but may be attached to the body  18  using a separate component if desired. The strut assembly  32  includes a second shoe  48  that is pivotally attached to the pivot plate  46  at a second shoe axis  50 . 
         [0020]    In  FIG. 3 , the pipe puller  16  is shown in a transport position. While in the transport position, the pipe puller  16  may be maneuvered by the operator to a desired location by rolling the pipe puller  16  on the wheels  28 . While in the transport position, the pipe puller  16  may be maneuvered to a location where it will be used to pull the second pipe section  12 . As shown, the pipe puller  16  is located within the first pipe section  10  and the pipe puller axis  20  is generally aligned with the first longitudinal axis  10   c.    
         [0021]    The pipe puller  16  is then placed in an initial use position, shown in  FIG. 4 . The pipe puller  16  is tipped by rotating the body  18  about the wheel axis  26  so that the front end  22  is in contact with a first wall  10   e  of the first pipe section  10 . The strut assembly  36  is rotated about the strut axle  38  so that the first shoe  42  is in contact with a second wall  10   f  of the first pipe section  10 . It should be appreciated that it may be necessary to adjust the length of the strut  34  so that the first shoe  42  is in contact with the second wall  10   f.  It should be appreciated that the illustrated first wall  10   e  may be considered the floor of the first pipe section  10  and the illustrated second wall  10   f  may be considered the ceiling of the first pipe section  10 . However, the first wall  10   e  and second wall  10   f  may be other desired surfaces of the first pipe section  10 . 
         [0022]    With the pipe puller  16  in the initial use position, the strut actuator  44  is extended to move the pipe puller  16  to a set position, shown in  FIG. 5 . As previously described, the strut actuator  44  is pivotally connected to the strut  34  and to the pivot plate  46 . When the strut actuator  44  is extended, it causes the pivot plate  46  to rotate relative to the body  18  about the strut axle  38 . This causes the second shoe  48  to move downward relative to the body  18  until the second shoe  48  engages the first wall  10   e  of the first pipe section  10 . At this point, further extension of the strut actuator  44  continues to rotate the pivot plate  46  relative to the body  18 , and will cause the body  18  to rise relative to the second shoe  48  and relative to the first wall  10   e.  In the illustrated embodiment, the strut actuator  44  is extended until the second shoe axis  50  is in-line with a centerline  52  of the strut. 
         [0023]    It should be appreciated that in the set position, the first shoe  42  is compressed against the second wall  10   f  and the second shoe  48  is compressed against the first wall  10   e.  The strut  34  is wedged in the first pipe section  10 , while the body  18  is able to rotate relative to the strut assembly  36  about the strut axle  38 . The pipe puller  16  includes a main actuator  54  that may be used to pull the second pipe section  12 . The illustrated main actuator  54  is a hydraulic cylinder, but may be any desired force generating device. The main actuator  54  may be driven by the power unit  45 . The operation of the main actuator  54  to pull the second pipe section  12  is conventional in the art and will not be described in detail. It should be appreciated that both the strut actuator  44  and the main actuator  54  may be operated using a wireless remote control (not shown). 
         [0024]    It should be appreciated that when the pipe puller  16  is in the initial use position (shown in  FIG. 4 ), the body  18  is supported on the second wall  10   f  by the wheels  28 , and the supporting surface of the wheel  28  is farther from the body  18  than the second shoe  48  is. However, when the pipe puller  16  is in the set position (shown in  FIG. 5 ), the body  18  is supported on the second wall  10   f  by the second show  48 , and the second shoe  48  is farther from the body  18  than the wheel  28  is. 
         [0025]    When the operator wishes to remove the pipe puller  16  from the set position, the strut actuator  44  is retracted. This causes the pivot plate  46  to rotate relative to the body  18  and causes the pipe puller to move from the set position shown in  FIG. 5  to the initial use position shown in  FIG. 4 . It should be appreciated that the body  18  initially moves downward relative to the second shoe  48  until the wheels  28  are in contact with the first wall  10   e.  Then the second shoe  48  will be raised relative to the body  18  until the pipe puller  16  is in the initial use position. The strut  34  may then be rotated relative to the body  18  so that the first shoe  42  is not in contact with the second wall  10   f,  and the pipe puller  16  is then in the transport position shown in  FIG. 3 . 
         [0026]    Referring back to  FIG. 4  and  FIG. 5 , the pipe puller  16  has an initial overall strut height  56  when the pipe puller  16  is in the initial use position (shown in  FIG. 4 ), and a set overall strut height  58  when the pipe puller is in the set position (shown in  FIG. 5 ). The initial overall strut height  56  and the set overall strut height  58  of the pipe puller  16  are measures of the distance between the first shoe  42  and the second shoe  48 . The set overall strut height  58  is greater than the initial overall strut height  56 . This is caused by the rotation of the pivot plate  46  moving the second shoe  48  downward relative to the body  18 . In the illustrated embodiment, the rotation of the pivot plate  46  causes the set overall strut height  58  to be 1.75-inches greater than the initial overall strut height  56 . However, it should be appreciated that the change in the set overall strut height  58  may be any other desired value. It should be appreciated that the increase in set overall strut height  58  may be changed by using different dimensions for the pivot plate  46 , or by changing the clearance between the second shoe  48  and the first wall  10   e  when the pipe puller  16  is in the transport position. 
         [0027]    The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.