Abstract:
A pipe wrench is provided having a elongated housing, a motor disposed within the housing, and a pipe attachment structure connected to the housing. A rotatable shaft extends from within the housing, transverse to the axis of the housing, and is rotated by the motor. A pair of drive rollers are mounted on the shaft. The pipe wrench further includes a support structure on the housing, a curved retaining arm pivotally mounted on the support structure, and a plurality of free-spinning rollers mounted on the retaining arm. In use, a pipe is placed within the retaining arm in contact with the free-spinning rollers and the handle is moved to bring the drive rollers into contact with the pipe. The motor causes the shaft to rotate which then rotates the pipe.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is continuation-in-part of U.S. application Ser. No. 09/325,767, filed Jun. 4, 1999.  
     
    
     
       TECHNICAL FIELD  
         [0002]    The present invention relates generally to a hand tool for rotating and installing pipes, and more particularly, to a powered pipe wrench.  
         BACKGROUND OF THE INVENTION  
         [0003]    Both powered and manually operated pipe wrenches for assembling and disassembling lengths of threaded pipe have long been known. Manual pipe wrenches include a jaw portion that can be tightened about a section of pipe and a handle that is used to rotate the pipe. Powered pipe wrenches generally include a chain or similar flexible element that wraps around the pipe, a mechanism for tightening the chain about the pipe, rollers for engaging the sidewall of the pipe, and a drive mechanism for moving the chain or rollers to rotate the pipe while the handle of the wrench is held in one position.  
           [0004]    A relatively large amount of force is required to keep a wrench in position on a pipe when the pipe is turned, and it is often difficult to hold a pipe tightly enough to prevent such relative motion.  
           [0005]    While some prior art devices for rotating a pipe adequately prevent relative movement between the pipe and the wrench, these devices, especially powered pipe wrenches, can be cumbersome and require considerable labor and time to attach securely to the pipe. Therefore, there is a need for a powered pipe wrench that can quickly and effectively be secured into a use position to grip a pipe or similar object.  
         SUMMARY OF THE INVENTION  
         [0006]    These problems and others are addressed by the present invention which comprises a pipe wrench having an elongated housing, a motor disposed within the housing, and a pipe attachment structure connected to the housing. A rotatable shaft extends from within the housing, transverse to the axis of the housing, and is rotated by the motor. A pair of drive rollers are mounted on the shaft. In a preferred embodiment, the pipe wrench further comprises a support structure on the housing, a curved retaining arm pivotally mounted on the support structure, and a plurality of free-spinning rollers mounted on the retaining arm. In use, a pipe is placed within the retaining arm in contact with the free-spinning rollers and the handle is moved to bring the drive rollers into contact with the pipe. The motor is then engaged to rotate the drive rollers and rotate the pipe while it is held securely between the drive rollers and the free-spinning rollers on the support structure.  
           [0007]    It is therefore a primary object of the present invention to provide an improved powered pipe wrench that is simple and easy to use.  
           [0008]    It is a further object of the present invention to provide a powered pipe wrench that is adjustable to fit pipes of various sizes.  
           [0009]    It is another object of the present invention to provide a powered pipe wrench having removable drive rollers that can be replaced with rollers suited for use with a particular type of pipe.  
           [0010]    It is still another object of the invention to provide a powered pipe wrench having exteriorly mounted rollers that are easy to clean and that are not prone to jamming.  
           [0011]    It is still a further object of the present invention to provide a powered pipe wrench with a mechanism for limiting the torque imparted by the wrench to a preset level.  
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0012]    These and other objects of the present invention will be appreciated and understood by those skilled in the art after reading the detailed description of the preferred embodiments of the invention together with the following drawings wherein:  
         [0013]    [0013]FIG. 1 is a perspective view of a pipe wrench according to the present invention;  
         [0014]    [0014]FIG. 2 is an exploded perspective view of the pipe wrench of FIG. 1 illustrating different structural components of the wrench;  
         [0015]    [0015]FIG. 3 is a perspective view of the retaining arm of the pipe wrench of FIG. 1;  
         [0016]    [0016]FIG. 4 is an exploded perspective view of a second embodiment of the present invention; and,  
         [0017]    [0017]FIG. 5 is a perspective view of a roller having embedded diamond chips for use with the wrench of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    Referring now to the drawings, wherein the showings are for the purpose of illustrating several embodiments of the invention only and not for the purpose of limiting same, FIG. 1 shows a pipe wrench  10  including an elongated housing  12  configured and dimensioned to be gripped by a user&#39;s hand. Elongated housing  12  has a receiving compartment  14  for housing a power source  16  such as, but not limited to, an electric motor, a hydraulic pump, or a pneumatic air pump for operating pipe wrench  10 . An operating switch  18  for turning power source  16  on and off is mounted on the outer surface of elongated housing  12  allowing the user to turn switch  18  on and off using his or her thumb while at the same time gripping pipe wrench  10 .  
         [0019]    Pipe wrench  10  further includes a support structure  20  substantially surrounding the outer surface of housing  12  and having a rectangular shape and including a pair of sidewalls  22 , a first end wall  24 , a second end wall  26 , and a top surface  30  defining a receiving area  28  therewithin. Receiving area  28  houses a drive mechanism  25  such as, but not limited to, a gear assembly. Such gear assembly is commonly known in the art, and for example, is described in U.S. Pat. No. 4,178,817 issued to Gibson on Dec. 18, 1979, which is incorporated by reference herein. Support structure  20  is connected to elongated housing  12  at first end wall  24  through which power source  16  operably connects to the gear assembly.  
         [0020]    Sidewalls  22  extend peripherally beyond the outer surface of housing  12  and above top surface  30  of support structure  20 , and define a channel  32  which extends in the direction of the housing axis  23  from second end wall  26  to first end wall  24  between top surface  30  and inner faces of sidewalls  22 .  
         [0021]    A plurality of apertures  34  are disposed in a line on each sidewall  22  in the direction of axis  23 . Each aperture  34  on one sidewall  22  is mirrored and aligned with a corresponding aperture  34  on the opposing sidewall  22 . Each aperture  34  is disposed slightly above top surface  30  and is configured and dimensioned to receive a mounting pin  36  having sufficient length to extend from one aperture  34  on one sidewall  22  to the corresponding mirrored aperture on the opposing sidewall  22 . As will be described herein, mounting pin  36  removably mounts a retaining arm  38  to support structure  20 . Mounting pin  36  is preferably configured and dimensioned to be frictionally fitted within aperture  34 , or alternatively, may be threaded at its opposing ends for receiving a bolt (not shown) to secure the mounting pin to the support structure.  
         [0022]    Support structure  20  further includes an extension piece  40  extending outwardly from second end wall  26 . Extension piece  40  mounts and supports a rotating shaft  42 . Extension piece  40  is integral with support structure second end wall  26  at one end and includes a shaft-receiving aperture  44  extending the width of extension piece  40 . Shaft-receiving aperture  44  is configured and dimensioned to removably and operably receive a rotating bushing  45  linked with drive mechanism  25 , such as the gear assembly described in the Gibson patent mentioned above. Rotating shaft  42 , preferably having a square cross section, is secured through rotating bushing  45  and is rotatable with the bushing in both clockwise and counter clockwise directions.  
         [0023]    A pair of drive rollers  46  are removably mounted on opposite ends of rotating shaft  42 . Each drive roller  46  has a square axial bore  48  which matches with the square cross sectional shape of rotating shaft  42 . One advantage of having an non-circular bore is to provide a non-slip engagement between drive rollers  46  and bushing  45 . Each drive roller  46  includes an outer toothed surface  50  for a better frictional contact with the outer surface of the pipe. Alternatively, each drive roller  46  may have a rubber outer surface  51  allowing the wrench to be safely used on different types of pipes, such as PVC pipes. A roller with a rubber outer surface is shown in FIG. 4. An alternate roller with a rubber or elastomeric surface impregnated with diamond chips  53  is shown in FIG. 5. These rollers snap on and off shaft  42  and can be changed quickly to match pipe material. Other types of rollers suited for other types of pipes could also be used. It should also be appreciated that the removable nature drive rollers  46  allows for access and cleaning of the dust and dirt build up around the rollers and the shaft  
         [0024]    Each drive roller  46  may also include a torque limiting clutch which can limit the amount of torque produced by the drive rollers. Such torque limiting clutches are well known from the torque wrench art and will not be described further herein.  
         [0025]    Referring now to FIG. 2, retaining arm  38  has a hook-shape configuration and is preferably manufactured from steel having a rectangular cross section with a pair of side walls  52 , a top wall  54 , and a bottom wall  56 . Retaining arm  38  further includes a first portion  58 , a second portion  60  extending from first portion  58  at an angle, preferably 90 degrees, a third portion  62  extending from the end of second portion  60  at an obtuse angle, and a fourth portion  64  extending from the end of third portion  62 , also at an obtuse angle. The portions are integral with one another and together form the hook-shaped retaining arm  38 .  
         [0026]    First portion  58  of the retaining arm includes an aperture  66  for receiving mounting pin  36  which extends between sidewalls  22 . Retaining arm  38  pivotally mounts on support structure  20  through mounting pin  36  where it can pivot in first or second directions about mounting pin  36 .  
         [0027]    [0027]FIG. 3 shows retaining arm  38  and a plurality of free spinning rollers that are mounted thereon. More specifically, a first pair of free spinning rollers  68  is rotatably mounted on each side  52  of arm  38  preferably at the angled connection point of second portion  60  with third portion  62  of the retaining arm. Similarly, a second pair of free spinning rollers  78  is mounted on opposing sides  52  of the retaining arm at the angled connection point of third portion  62  with fourth portion  64  of retaining arm  38 , and a third pair of free spinning rollers  80  is mounted on opposing sides  52  of the retaining arm at the end of fourth portion  64  of retaining arm  38 . It should be noted that a greater or lesser number of pairs of free spinning rollers could also be used without exceeding the scope of the present invention. It should further be appreciated that disposing the free spinning rollers in such configuration, i.e. at the angled connection points of each portion of the retaining arm, will allow the three pair sets of free spinning rollers to have good contact with, and therefore a better grip on pipes having a circular cross section, or other types of structures such as nuts, pipe fittings and the like. Furthermore, because the free spinning rollers are mounted on the outer portion of arm  38 , they are less likely to become jammed with dirt and other materials than are the interiorly mounted rollers known from the prior art. Each of the free spinning rollers includes a spindle  72  connected to the retaining arm, an outer portion  69  preferably made out of rubber or a similar material and a bore  70  for receiving spindle  72 .  
         [0028]    The gripping diameter of retaining arm  38  with respect to drive rollers  46  is adjusted by mounting the arm on different aperture  34  locations. This is done by removing retaining pin  36  from aperture  66 , moving the arm along the channel  32  and aligning aperture  66  on first portion  58  with the opposing pin receiving apertures  34  on each sidewall  22 . Mounting pin  36  is then inserted through one aperture  34  on one sidewall  22  and is extended through aperture  66  and the opposing aperture  34 , thereby pivotally mounting retaining arm  38  on support structure  20 .  
         [0029]    A range of pipe diameters can be accommodated by the subject pipe wrench when the arm is mounted in each of apertures  34 . This is because arm  38  rotates about mounting pin  36  to change the distance between the free spinning rollers and drive rollers  46 . There is some overlap between the diameters of pipe that can be accommodated when the pin is in adjacent apertures  34 , which allows the wrench to be used on pipes having a continuous range of diameters.  
         [0030]    The operation of the subject pipe wrench to rotate a given pipe will now be described. First, retaining arm  38  is attached to support structure  20  between sidewalls  22  at a location that will allow the pipe to fit between the free-spinning rollers and the drive rollers. If the space between the free spinning rollers and the drive rollers is too large or too small, the retaining arm is repositioned in a different set of apertures as necessary. Retaining arm  38  is then placed around the pipe with the free spinning rollers in contact with the pipe and held in place while the wrench housing is pivoted about connecting pin  36  to bring pipe drive rollers  46  in contact with the pipe. It should be appreciated that the resiliency of rubber type material of each outer portion  69  allows for a slight compression of the material. This slight compression helps third pair of free spinning rollers  80  mounted at the end of fourth portion  64  of retaining arm  38  to roll over the pipe as retaining arm  38  pivots to grip the pipe against drive rollers  46 .  
         [0031]    With the pipe firmly gripped between free spinning rollers  68  and the outer toothed surface  50  of drive rollers  46 , operating switch  18  is moved to actuate the power source which runs the drive mechanism to turn drive rollers  46  and rotate the pipe.  
         [0032]    Referring now to FIG. 4, a second embodiment of pipe wrench  10  is illustrated. Elements common to the both embodiments are identified with the same reference numerals. In this embodiment, one sidewall  22  of support structure  20  includes a plurality of notches  74  inclined away from retaining arm  38  and each notch  74  is aligned with a corresponding aperture  34  in the other sidewall. A shaft  82  is attached inside aperture  66  of first portion  58  of retaining arm  38 . Therefore, the retaining arm and the shaft are integral as one unit.  
         [0033]    In this embodiment, retaining arm  38  is pivotally mounted on support structure  20  by inserting one end of shaft  82  inside one aperture  34 , and placing the other end of shaft  82  inside corresponding notch  74  until the shaft rests on an arcuate surface  76  at the bottom of the notch. The gripping diameter of retaining arm  38  can be adjusted by placing the shaft at a different notch-aperture location on the support structure. The arm pivots about as the shaft pivots within the notch and the aperture.  
         [0034]    While preferred embodiments have been shown and described, various modifications and substitutions will become obvious to those skilled in the relevant arts upon a reading and understanding of the forgoing specification. For example, while the power source of the invention has been described as being a battery powered motor, a pneumatic or other device could be used to rotate the pipe engaging rollers without departing from the scope of this invention. Applicant intends that all such obvious modifications and additions be protected to the extent that they are defined by the several claims appended hereto.