A hole opener for use in the Horizontal Directional Drilling (HDD) Industry is provided having an interchangeable sleeve reamer. The hole opener is in the form of a three-piece tool comprising a top shaft member, an interchangeable sleeve member and a bottom sub member, the interchangeable sleeve member being configured to be securely and removably mounted onto the top shaft member such that is does not rotate freely about the axis of the shaft member. In one embodiment, the bottom sub member also is interchangeable with other bottom sub members.

RELATED APPLICATION INFORMATION  
       [0001]    This application claims the benefit of priority of U.S. provisional application Serial No. 60/260,266, filed in the United States Patent & Trademark Office on Jan. 9, 2001 in the names of Donald G. Morris, Sr. and David R. Morris, Sr. 
     
    
     
       FIELD OF INVENTION  
         [0002]    The present invention relates to a hole opener having a replaceable and interchangeable sleeve reamer for use in the Horizontal Directional Drilling (HDD) industry. In particular, the present invention relates to a hole opener in the form of a three-piece tool comprising a top shaft member, an interchangeable sleeve member, and a bottom sub member. The interchangeable sleeve member is configured to be securely and removably mounted onto the top shaft member such that it does not freely rotate about the axis of the shaft member. The hole opener having the interchangeable sleeve reamer can be used to cut into dirt, clay, soft rock and hard rock by quickly and easily interchanging the sleeve member.  
         BACKGROUND OF THE INVENTION  
         [0003]    The present invention is directed to a replaceable and interchangeable sleeve reamer for a hole opener for use in the Horizontal Directional Drilling (HDD) industry. The HDD industry generally pertains to the formation of holes for the laying of product, for example, water pipes, sewer lines, fiber optic cables, and the like. Included in the HDD industry are the River Crossing and Road Boring communities. In the HDD industry, the formation of the hole often requires the opening of a hole under a river bed or under existing roadway. When opening a hole under a river bed, existing roadway or other physical barrier, the hole is opened first at an certain angle to a desired depth, then continued horizontally to a desired distance and then back upward at a certain angle to an exit site. Typically, the hole is predrilled (i.e. pilot bored) by a one-piece drilling tool on a drill string, the drilling tool opening the hole first at the specific angle to the desired depth, then horizontally to the desired distance, then upwardly at a specific angle to the exit site. Once the hole is pilot-bored, the drilling tool is removed from the drill string and a hole opener is mounted on the drill string and pulled back through the hole with the drill string to open the hole to a larger diameter.  
           [0004]    Typically, a hole is opened in several stages, the number of stages depending upon the size (i.e. diameter) required for the hole. Although the actual cutting ability of the reamer is one reason why several stages are required, the main reason is the ability of the fluid to remove the cuttings from and out of the hole. For example, to form a 16″ diameter hole, in the first stage, a 4¾″ hole is pilot bored; in the second stage an 8 or 9″ reamer is used to widen the hole; in the third stage, a 12 or 13″ reamer is used, and in the fourth stage, a 16″ reamer is used, fluid being used in each stage to remove additional cuttings from the hole.  
           [0005]    In conventional practice, in each stage, a different hole opener is required to open the hole to a larger size. The typical hole opener currently used in HDD is a one-piece tool having a top shaft, a bottom sub and a reamer element. Therefore, after each stage, the existing hole opener must be removed from the drill string and a new hole opener capable of opening a larger diameter hole must be mounted to the drill string. This practice not only requires the purchase and use of several hole openers to complete one hole opening, it also significantly increases the amount of time necessary to open the hole since each existing hole opener must be removed from the drill string and a successive hole opener must be mounted on the drill string.  
           [0006]    Drilling tools for use in oilfield applications have been developed which use interchangeable drill bits, reamer-stabilizers and other cutting tools. For example, U.S. Pat. No. 1,562,449 to Herrin, issued Nov. 24, 1925 and U.S. Pat. No. 2,506,795 to Koeln, issued May 9, 1950, disclose drilling tools for pre-drilling the initial pilot bore for a wellbore, each tool utilizing an arrangement of keys and slots to selectively prevent relative rotation between the parts thereon. However, neither drilling tool is adapted for opening the hole to the desired size by pulling back the tool and drill string. Rather, each of these drilling tools are lifted out of the well bore while the drill string remains intact and in the wellbore. U.S. Pat. No. 4,953,640 to Kurt, issued Sep. 4, 1990, discloses a quick detach bit apparatus for quickly changing drill bits on an oil field drilling tool for use in a wellbore. Kurt uses an arrangement of alternating splines and grooves provided on a drill bit for mating engagement with a corresponding arrangement provided on a chuck. The arrangement enables quick release of the drill bit and also prevents relative rotation between the bit and chuck.  
           [0007]    Removable cutting elements for drilling implements in oil field applications also are known in the prior art. For example, U.S. Pat. No. 2,210,824 to Walker, Sr., issued Aug. 6, 1940, discloses a rotary drilling tool comprising a plurality of tool elements that are threaded over a portion of the tool body and are held captive between opposing locking collars. In U.S. Pat. No. 3,322,217 to De Orr Cook, issued May 30, 1967, a reaming tool is provided having a sleeve section that is threaded over a reduced diameter portion of a mandrel and held captive thereon by a section of drill pipe that is threaded onto the end of the mandrel. U.S. Pat. No. 4,549,613 to Case, issued Oct. 29, 1985, discloses a downhole tool for use as an oilfield tool, which utilizes a replaceable sleeve member. Case comprises two replaceable tool sleeve sections that are assembled about a drill stem. The sleeve sections are elongated cylindrical half sleeve sections which are mountable on and removable from a tool body.  
           [0008]    None of these oil field drilling tools can be used in the HDD industry since the drill string remains in the wellbore and that they are not configured for all types of angled drilling and horizontal drilling. Further, the use of the term “reamer”, when used in reference to oil field applications, is meant to indicate a drilling tool which centralizes and stabilizes the drill hole. In the oil field application, once a pilot bore is drilled, a tool is mounted on the existing drill string and reams the pilot bore to ensure a perfect cylindrical hole; hence the term “reamer”. Thus, if a 8¾″ hole is pre-drilled, an  8¾″ reamer is mounted somewhere near the top of the drill string to keep it centered in the hole and to maintain the hole at  8¾″ diameter. In the oil field application, the reamer is not used to further open the hole to a larger diameter.  
           [0009]    Accordingly, a need still exists for a hole opener having an interchangeable sleeve reamer. Such a hole opener should be configured such that an interchangeable sleeve reamer can be quickly and easily replaced with another interchangeable sleeve reamer. In addition, the interchanging of sleeve reamers should not require that the hole opener be removed from the drill string. Such a hole opener having an interchangeable sleeve reamer also should be capable of interchanging bottom sub members. Moreover, such a hole opener having an interchangeable sleeve reamer should be capable of opening a hole in successive stages and remove the cuttings or solids out of the hole in order to obtain a hole having the desired diameter.  
         SUMMARY OF THE INVENTION  
         [0010]    Accordingly, it is an object of the present invention to provide a hole opener having an interchangeable sleeve reamer.  
           [0011]    It is also an object of the present invention to provide a hole opener having an interchangeable sleeve reamer wherein the hole opener is configured such that an interchangeable sleeve reamer can be quickly and easily replaced with another interchangeable sleeve reamer.  
           [0012]    It is another object of the present invention to provide a hole opener having an interchangeable sleeve reamer which does not required that the hole opener be removed from the drill string during the interchanging of sleeve reamers.  
           [0013]    It is an additional object of the present invention to provide a hole opener having an interchangeable sleeve reamer which also includes an interchangeable bottom sub member.  
           [0014]    It is a further object of the present invention to provide a hole opener having an interchangeable sleeve reamer which can open a hole in successive stages to obtain a hole having the desired diameter simply by the sequential replacement of an interchangeable sleeve reamer with an interchangeable sleeve reamer having a larger diameter.  
           [0015]    It is yet another object of the present invention to provide a hole opener having an interchangeable sleeve reamer which can remove the cuttings or solids out of the hole during the opening of the hole.  
           [0016]    Additional objects, advantages and novel features of the invention will be set forth in part of the description and claims which follows, and in part will become apparent to those skilled in the art upon examination of the following specification and claims or may be learned by practice of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    The present invention will be better understood with reference to the appended drawing sheets, wherein:  
         [0018]    [0018]FIG. 1 is an exploded side perspective view of the hole opener having an interchangeable sleeve reamer of the present invention.  
         [0019]    [0019]FIG. 2 is a cross-sectional view taken along the line A-A of the top shaft member of the hole opener of the present invention.  
         [0020]    [0020]FIG. 3 is a bottom perspective view of the interchangeable sleeve reamer of the hole opener of the present invention.  
         [0021]    [0021]FIG. 4 is a perspective view of a formed keyway slot and key member arrangement of the present invention.  
         [0022]    [0022]FIG. 5 is a perspective view of an alternative embodiment of the hole opener having an interchangeable sleeve reamer of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0023]    Referring to FIG. 1, the hole opener having an interchangeable sleeve reamer, generally designated  1 , comprises a top shaft member  10 , an interchangeable sleeve member  20  and a bottom sub member  30 . As particularly shown in FIGS. 1 and 2, the top shaft member  10  comprises a externally threaded lower end  11 , a distal second end  12 , an elongated cylindrical body  13  and at least two external keyway half-slots  14  disposed longitudinally along a portion of the outer surface  15  of the elongated cylindrical body  13 , each external keyway half-slot  14  having a lower end  16  proximal to lower end  11 . Preferably, three external keyway half-slots  14  are spaced 120° apart about the outer circumference of the elongated cylindrical body  13  as shown in FIG. 2. In a preferred embodiment, each external keyway half-slot  14  is about one quarter inch (¼″) in depth and about five inches (5.0″) in length. However, it is to be understood that other dimensions of the keyway half-slots  14  are contemplated to be within the scope of the present invention.  
         [0024]    Interchangeable sleeve member  20  comprises an upper end  21 , a lower end  22 , a body  23  and at least two internal keyway half-slots  24  as particularly shown in FIGS. 1 and 3. The internal keyway half-slots  24  are configured with the same dimensions as the corresponding external keyway half-slots  14 . Each internal keyway half-slot  24  is disposed from the lower end  22  and longitudinally along a portion the internal surface  25  of body  23 .  
         [0025]    Preferably, three internal keyway half-slots  24  are spaced 120° apart about the inner circumference of the body  23  as shown in FIG. 3. In a preferred embodiment, each internal keyway half-slot  24  is about one quarter inch (¼″) in depth and about five inches (5.0″) in length. However, it is to be understood that other dimensions of the internal keyway half-slots  24  are contemplated to be within the scope of the present invention, provided that each internal keyway half-slot  24  is configured with the same dimensions as the dimensions of a corresponding external keyway slot  14 .  
         [0026]    The bottom sub member  30  comprises an internally threaded first end  31 , an elongated cylindrical body  33  and a distal second end  32  as particularly shown in FIG. 1. Internally threaded first end  31  is configured to engage the externally threaded first end  11  of top shaft member  10 . In this manner, top shaft member  10  and bottom sub member  30  can be removably secured to one another by threadingly engaging first ends  11  and  31 .  
         [0027]    In assembling the hole opener  1  of the present invention, the upper end  21  of the interchangeable sleeve member  20  is slidingly introduced over the lower end  11  of the top shaft member  10  and upwardly onto the elongated cylindrical body  13  such that the lower end  22  of the interchangeable sleeve member is parallel with the lower ends  16  of the external keyway half-slots  14 . The interchangeable sleeve member is rotated about the top shaft until each external keyway half-slot  14  is aligned with a corresponding internal keyway half-slot  24 , thereby forming at least two (2) keyway slots  44 , as shown in FIG. 4. In the preferred embodiment, each keyway slot  44  is about one-half inch (½″) in width and about five inches (5″) in length. However, it is to be understood that other dimensions of the keyway slots  44  are contemplated to be within the scope of the present invention.  
         [0028]    In order to prevent the interchangeable sleeve member from freely rotating about the axis of the top shaft  10 , a key member  40  is inserted into each keyway slot  44 . Each key member  40  comprises a first end  41  and a second end  42  and is dimensioned to have the same length and a slightly larger width than the keyway slot  44 . Thus, in the preferred embodiment, each key member  40  is about five inches (5.0″) in length and slightly more than one-half inch (½″) in width. With this configuration, once second end  42  of the key member is introduced into the keyway slot  40 , the first end  41  is tapped such that the entire length of the key member is snugly secured within the keyway slot  44 . First end  41  can be provided with a tab or notch to facilitate removal of the key member from the keyway slot.  
         [0029]    The keyway slot/key member arrangement enables the user to quickly and easily replace the interchangeable sleeve member  20  with another interchangeable sleeve member. Suitable interchangeable sleeve members include, for example, a Split Bit Reamer for dirt, soft and hard rock, a Wing Cutter for dirt and soft rock, and a Fly Cutter for dirt and soft rock. In this manner, the versatility of the hole opener with an interchangeable sleeve reamer provides numerous possibilities for utilizing the hole opener with other downhole devices.  
         [0030]    Once the interchangeable sleeve member  20  is placed over the top shaft  10 , the bottom sub member  30  is removably secured to the top shaft  10  by the threaded engagement of lower end  11  and first end  31 . The bottom sub member  10  also can be interchanged other sub tools when different work in the hole is required. Suitable interchangeable bottom sub members include, for example, a Solid Sub to keep fluid passage stopped at the back of the reamer, a Pulling Eye Sub which hooks up to a Swivel to pull product (sewer line, optic cable) through the hole, a Barrel Reamer which swabs out the hole, and like sub members.  
         [0031]    Referring again to FIG. 1, the top shaft member  10  is provided with a plurality of fluid holes  17  and interchangeable sleeve member  20  is provided with a plurality of fluid holes  27 . Preferably the top shaft member  10  and interchangeable sleeve member  20  each have three fluid holes spaced 120° apart and which can be aligned along with the keyway half-slots. Thus, all such constructed interchangeable sleeve members can be interchangeable. These fluid holes  17  and  27  are for the passage of fluid such that cuttings and other solids can be removed from the hole.  
         [0032]    Referring now to FIG. 5, an alternative embodiment for removably mounting the interchangeable sleeve member  120  over the top shaft member  110 . In this embodiment, rather than the use of the keyway slot/key member arrangement to prevent the interchangeable sleeve member from rotating about the axis of the top shaft member, the top shaft member is provided with a plurality of apertures  114 , preferably six apertures, about its circumference. The interchangeable sleeve member  120  is provided with a plurality of apertures  124 , preferably six apertures, dimensioned with the same diameter as apertures  114 . A rod or bolt member  140  is provided having a slightly larger diameter than the apertures  114  and  124 . When the apertures  124  are aligned with the apertures  124 , a bolt member  140  is tapped into and through aperture  114  and into aperture  124 . Although this arrangement is meant to be an alternative means for removably mounting the interchangeable sleeve member to the top shaft member, it will be apparent to those skilled in the art that other arrangements can be utilized to enable the interchangeable sleeve member to be removably mounted over the top shaft member and that such other arrangements are considered to be within the scope of the present invention.  
         [0033]    While particular embodiments of the invention have been described, it will be understood, of course, that the invention is not limited thereto, and that many obvious modifications and variations can be made, and that such modifications and variations are intended to fall within the scope of the appended claims.