Abstract:
A pipe extraction tool that grips the inside of a pipe or other hollow tube to facilitate removal of the object. The extraction tool employs a pick that is rotated from an axial position to engage and pierce the inner diameter of the pipe for removal.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    Not applicable. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable. 
       REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX 
       [0003]    Not Applicable. 
       BACKGROUND OF THE INVENTION 
       [0004]    1. Field of the Invention 
         [0005]    The present invention relates to a pipe extraction tool. More specifically, the present invention relates to a tool for extracting pipe or the like by gripping the inside of the pipe to facilitate removal thereof 
         [0006]    2. Description of the Related Art 
         [0007]    Pipes or other hollow tube-shaped devices are used in many situations as conduits for liquids and gases, as connectors for mechanical devices, and for special applications such as holders for removable pylons that separate traffic lanes. It is not uncommon for removal of a pipe to be difficult because the section to be removed is underground or firmly embedded inside another element, and therefore difficult to grasp on the exterior. Several tools have been developed to facilitate such removal, but most have complex expanding mechanisms that are expensive to manufacture due to their complexity. These expanding mechanisms also tend to be inadequate for removal when excessive force is required because their gripping strength is limited to sliding frictional force. For example, U.S. Pat. No. 7,448,303 teaches a pipe extraction tool where wrench jaws are expanded to engage the internal diameter of the pipe. Such a tool relies solely on frictional sliding force to remove the pipe, and therefore, is ineffective for pipes that are extremely difficult to remove. Other tools have been developed that can be screwed into the pipe for removal, however these tools are only useful if the walls of the pipe are sufficiently thick to allow engagement without obliterating them. The screw mechanisms also cause complete destruction of the pipe to be removed, preventing re-use of the object. The present invention resolves these issues by providing an elegant and inexpensive mechanism that pierces the interior of the pipe, creating maximum gripping power while only impacting a small portion of the interior of the object to be removed. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The present invention is a Pipe Extraction Tool comprised of a threaded shaft with a positioning nut that drives a cylindrical collar into a rotatable pick. The cylindrical collar is moved axially along the threaded shaft by rotating the positioning nut on the threaded shaft. Prior to insertion of the tool in the pipe to be extracted, the positioning nut is moved upward such that the cylindrical collar is raised away from the rotatable pick. In that position, the rotatable pick is aligned generally axially with the threaded shaft so that it can easily slide inside the pipe. After insertion of the tool into the pipe, the positioning nut is tightened such that it forces the cylindrical collar to engage the rotatable pick, moving it into a horizontal position and driving the sharp pick end into the inner wall of the pipe. The tool can then be pulled axially to extract the pipe. After extraction of the pipe, the positioning nut is loosened, backing the cylindrical collar away from the rotatable pick, and allowing the rotatable pick to return to the axial position, thus releasing the tool from the pipe. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0009]    A more complete understanding of the present invention may be derived by referring to the detailed description when considered in connection with the figures, wherein like reference numbers refer to similar items throughout the figures, and: 
           [0010]      FIG. 1  is a side view of one embodiment of the Pipe Extraction Tool showing the cylindrical collar raised so that it is not engaging the rotatable pick; 
           [0011]      FIG. 2  is a side view of the Pipe Extraction Tool showing the cylindrical collar in the downward position such that the rotatable pick is forced into a horizontal position; 
           [0012]      FIG. 3  shows several close-up views of the cylindrical collar and rotatable pick; 
           [0013]      FIG. 4  shows the cylindrical collar in the downward position such that it is fully engaging the rotatable pick, and wherein the cross-section view is shown with the pipe in dotted outline and where the pipe is shown for illustrative purposes only and does not form a part of the invention; and 
           [0014]      FIG. 5  shows two alternate configurations, one where the handle of the Pipe Extraction Tool forms a loop that can accommodate a large cross-bar for additional leverage, and the other with no handle attachment so that any attachment can be screwed on to the threaded end. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    In the following detailed description of the invention, reference is made to the accompanying drawings which form a part of the disclosure and which show by way of illustration, and not of limitation, specific embodiments by which the invention may be practiced. The drawings, the foregoing discussion, and the following description are exemplary and explanatory only, and are not intended to limit the scope of the invention or its application in any manner. 
         [0016]    The present invention is comprised of a Threaded Shaft  101 , a Positioning Nut  102 , a Cylindrical Collar  103 , an End. Nut  106  with a Dowel Assembly  301 , and a Rotatable Pick  104 . The Threaded Shaft  101  is preferably made of steel and has a Handle  105  at the top suitable for manual gripping. In an alternate configuration as shown in  FIG. 5 a   , the Threaded Shaft  101  may be configured with a Loop  501  at the top that is suitable for inserting a long shaft for improved leverage to extract the pipe. In yet another alternate configuration, as shown in  FIG. 5 b   , there is no handle attachment so that any attachment can be screwed on to the top threaded end of the Threaded Shaft  101 . An End Nut  106  is permanently attached or firmly secured onto the bottom of the Threaded Shaft  101 . 
         [0017]    A Dowel Assembly  301  is inserted horizontally through the End Nut  106  such that it secures the Rotatable Pick  104  to the End Nut  106 , while allowing the Rotatable Pick  104  to rotate around the Dowel Assembly  301  axis. The Dowel Assembly  301  may be either a simple metal dowel with a nut or welded component on each end, or it may be made from a screw, nut and washer combination, or other suitable configuration, as long as the Rotatable Pick  104  is free to rotate around the Dowel Assembly  301  axis, and the overall length of the Dowel Assembly  301  does not exceed the inner diameter of the Pipe  401  that is to be extracted. The End Nut  106  preferably has a flat surface on the side where the Rotatable Pick  104  is located so the Rotatable Pick  104  may rotate without obstruction or friction around the Dowel Assembly  301  axis. 
         [0018]    The Rotatable Pick  104  is made of steel or other suitable material that is stronger than the material of the Pipe  401  that is to be extracted such that when the Rotatable Pick  104  is forced into the side of the Pipe  401 , it pierces the material of the Pipe  401  and the Rotatable Pick  104  is not deformed. The Rotatable Pick  104  preferably has a sharp point on both ends, but in an alternate configuration, may have a single sharp point as shown in  FIG. 5   b.    
         [0019]    In a preferred embodiment, there is a Pick Stop  302  inserted in or attached to the End Nut  106  that prevents the Rotatable Pick  104  from moving past a vertical angle when the Cylindrical Collar  103  is in the raised position. The Pick Stop  302  ensures that when the Cylindrical Collar  103  is moved against the Rotatable Pick  104 , the Cylindrical Collar  103  engages the side of the Rotatable Pick  104  so that it is forced into a horizontal position as shown in  FIGS. 2 and 4 . 
         [0020]    The Cylindrical Collar  103  is preferably made of steel and has an inner diameter that is large enough to fit over the End Nut  106 , but is small enough to engage the Rotatable Pick  104 . After the tool is inserted into the Pipe  401  that is to be extracted, the Positioning Nut  102  is tightened downward, forcing the Cylindrical Collar  103  against the Rotatable Pick  104  and moving it into a horizontal position. The Rotatable Pick  104  and the outer diameter of the Cylindrical Collar  103  are configured such that when the Rotatable Pick  104  is in approximately the horizontal position, the Cylindrical Collar  103  is forced against one side of the Pipe  401 , and the Rotatable Pick  104  digs into the other side of the Pipe  401 , providing maximum gripping power as shown in  FIG. 4 . With the Rotatable Pick  104  digging into the inner diameter of the Pipe  401 , the tool is used to extract the Pipe  401 . 
         [0021]    After extraction of the Pipe  401 , the Positioning Nit  102  is loosened to allow the Rotatable Pick  104  to return to an axial orientation and releasing it from the inner diameter of the Pipe  401 . 
         [0022]    Many modifications and variations of this invention may be made without departing from its spirit and scope, as will be appreciated by those skilled in the art. For example, rather than using a Pick Stop  302  to ensure the Cylindrical Collar  103  properly engages the Rotatable Pick  104 , a Rotatable Pick  104  with only a single sharp point could have a symmetrical shape with a rounded back end that would serve the same purpose. The embodiment as described herein was chosen and described in order to best explain the principles of the invention and its practiced applications.