Abstract:
A hole opener ( 10 ) having a tubular body ( 11 ) with threaded ends ( 12, 14 ) for connection in a drill string. The hole opener provides slots or grooves ( 21, 21 ′) along its longitudinal axis ( 16 ) into which are inserted cutter arm support members ( 30, 30′, 60, 60 ′) which may be screwed, ( 43 ) pinned ( 68 ) or bolted ( 168 ) to the body ( 11 ) to permit easy replacement of the support arms ( 30 ). The grooves ( 21, 21 ′) in the body ( 11 ) of the hole opener ( 10 ) also provide a spindle ( 20 ) spatially aligned with the groove ( 21, 21 ′) to support the proximal end of a rotatable journal body ( 28 ) supporting the cutter body ( 25 ) providing hard facing for grinding of the bore hole to be enlarged. The support arms ( 30 ) at their distal end provide further support for the cutter journals ( 70 ). The hole opener ( 10 ) also may provide pressure compensated lubrication mechanism ( 71 ) to provide grease to the bearing surfaces to increase their service life and thereby extend the useful life of the tool.

Description:
RELATED CASES 
     This application claims priority to my provisional patent applications, Application Ser. No. 60/134,100, filed May 14, 1999, and application Ser. No. 60/160,771, filed Oct. 21, 1999, for the same invention. 
    
    
     BACKGROUND-FIELD OF INVENTION 
     The present invention relates to an improved hole opener for use in increasing the diameter of holes in drilling and more specifically, to a hole opener having a set of arms that may be changed to increase the size of the cutter allowed to be used so that a variety of different sized holes might be drilled using the same hole opener body. 
     In the drilling industry, whether for exploration of oil and gas, mining, water well development or the like, an operator may desire to widen the existing diameter of a hole previously drilled. A number of prior art devices have been used for enlarging such holes. Most hole openers currently in use provide a fixed-arm arrangement which supports a pin through the cutter shell and are prone to failure when excessive wear allows the arm to fail and the pin to collapse, with the possibility that such devices might then be stuck in the hole, necessitating an expensive retrieval job. 
     SUMMARY OF THE INVENTION 
     The present invention provides a tubular body with threaded connections at either or both ends to enable connection in a drill string, and further providing a passage therethrough for the passage of drilling fluid, including air. The tubular body supports a plurality of detachable support arms for each cutter which are bolted, pinned, or otherwise removably attached to the tubular body and which engage the outer or distal end of a journal body. The journal body is engaged at its proximal end on a spindle providing an eccentric or otherwise non-circular profile so that the journal cannot be rotated on the spindle. Alternatively, the spindles may also be recessed in the tubular body providing additional structural support for the journals, and further providing a restraint to movement of the journal on the spindle. The journal provides bearings to facilitate rotation of a cutter on the journal. The cutter shell is carried on the journal body and eliminates the customary pin arrangement through the axis of rotation of the cutter body, which was used to support all known prior art hole openers. A pressure compensated means of lubricating the bearings on the journal is also provided thereby increasing the life of the bearings and the useful life of the hole opener. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side cut-away view of a form of the invention showing a smaller cutter shell and arm. 
     FIG. 2 is another cut-away view of a form of the invention showing the tubular body with a larger cutter shell and arm. 
     FIG. 3 is an enlarged cross-sectional view of the cutter support arm, journal and cutter shell supported on the tubular body. 
     FIG. 4 is an end view of the small cutter shells on the tubular body. 
     FIG. 5 is an end view of the larger cutter shells on the same tubular body shown in FIG.  4 . 
     FIG. 6 is cross-sectional side view of an alternative embodiment for use in larger diameter holes. 
     FIG. 7 is an end view of the large diameter hole opener of FIG.  6 . 
     FIG. 8 is a sectional view of a second form of embodiment of the invention with a pinned cutter arm. 
     FIG. 9 is a sectional view of the second form of embodiment with a larger cutter arm and larger cutter cone. 
     FIG. 10 is an enlarged cross-sectional view of the cutter support arm of FIG.  8 . 
     FIG. 11 is a sectional view of the cutter body through the section line of FIG.  8 . 
     FIG. 12 is a partial sectional view of the large diameter opener showing the attachment of the cutter arm secured to the body by the pins. 
     FIG. 13 is a partial sectional view of the large diameter opener showing an alternative attachment of the cutter arm secured to the body by cap head screws and secured by smaller diameter cap head screws. 
     FIG. 14 is a partial sectional view of another embodiment of the large diameter opener having a recessed seat for the journal body for strength and rigidity and further providing a lubrication reservoir and system for lubricating the bearings during operation. 
     FIG. 14 a  is a cross-sectional view of the recessed groove area formed on the body of the hole opener. 
    
    
     DESCRIPTION OF THE INVENTION 
     The present invention is for a hole opener providing the means to use the tool for opening more than one diameter with the same tubular body by changing the support arm, the journal supported by that arm and the cutter shell. 
     In FIG. 1, the hole opener  10  provides a threaded pin  12  and a threaded box  14  at the other end to connect the tubular body  11  to a drill string or the like (not shown). The tubular body  11  provides a passage  16  through its longitudinal extent to allow the passage of drilling fluid, which can be liquid or air used to carry the cuttings from the well bore (not shown). The tubular body  11  is integrally formed with a larger diameter portion  19 . A stair-stepped groove or rabbet  21  extending from adjacent the larger diameter portion  19  to adjacent the eccentric spindle  20  formed on the body  11  to accept support arm  30 . Support arm  30  is secured to the tubular body by a plurality of socket head cap screws  43 ,  43 ′ and  43 ″ of varying lengths that attach the support arm body  30  to the body  11 . Each of the socket head cap screws is further secured in the support arm body  30  by retainer ring  45  which is inserted in a groove  45 ′ formed on the interior surface of the support arm. The support arm body  30  provides a spindle  31 , which fits into the space formed by a journal  28  at its distal end. Journal  28  is formed with an eccentric or non-circular profile  22  on its proximal end to mate with spindle  20  on the tubular body  11  to prevent rotation of the journal  28  in either direction, allowing the hole opener to be used in either direction. Journal  28  provides bearings  27  and bearing races  29  to facilitate rotational movement of cutter shell body  25  on the journal  28 . Each of the cutter shells supported on the multiple support arms may be provided with hard facing in a manner well known to those skilled in the art, or may be provided with tungsten carbide buttons (not shown) also in a well known commercial manner. In the preferred embodiment, three support arm-cutter assemblies are provided on the hole opener  10 , but any number greater than three may be provided depending on the size of the hole desired. 
     Adjacent the cutter shell spindle  20 , the diameter of the body  11  is only increased to an amount equivalent to the smallest hole which the operator may wish to open and provides hard facing (not shown) or tungsten carbide buttons  18  to minimize wear on the tubular body  11  as it moves through the formation to be widened. 
     Tubular body  11  is additionally formed to provide passageway  50  which permits communication of the drilling fluid from the longitudinal passageway  16  to adjacent the cutter bodies through nozzle holder  52  and nozzle  53  in a manner well known in the drilling industry. The jetting nozzle  53  is recessed in the body of the largest diameter portion of the tubular body  11  spaced between each of the support arms. 
     FIG. 2 describes the hole opener with the same sized body as shown in FIG. 1, with the larger support arm  60 , journal  70  and cutter body  80  for widening the diameter of a larger hole with the same tubular body  11 . The tubular body  11  may be fitted with alternative sets of support arms  60 , larger journals  70 , and larger cutter shells  80  for a variety of wider hole sizes desired. The socket head cap screws  65 ,  66 , and  67  are longer to support the larger support arm  60  on the body, but otherwise function in the same manner and are installed on the body in the same manner as the bolts for the smaller diameter hole opener of FIG.  1 . The function and operation of the hole opener would be equivalent to the hole opener described in connection with FIG.  1 . 
     FIG. 3 is an enlarged partial view of the hole opener of FIG. 2 showing the stair-stepped groove  21  formed in the large diameter portion body of the tubular body  11 , with the socket head cap screws  65 ,  66 , and  67 , and retainer rings  45  seated in retainer ring grooves  45 ′. Cutter shell journal  70  provides additional roller bearings to support the additional cutting surface of the cutter shell  80  and facilitate rotational movement of the cutter shell on the journal. FIG. 3 more clearly shows the hard facing, which may be placed on the exterior surface  81  of the dihedral shaped cutter shell body. The face of cutter shell  80  may again be provided with either hard facing with grooves commonly referred to as a mill tooth cutter in the manner well known in the art or may provide tungsten carbide buttons (not shown). 
     Socket head cap screws  65 ,  66 , and  67 , shown in FIG. 3 are one side view of two adjacent rows of bolts (for a total of six bolts) securing the support arm  60  to the tubular body  11  in the stair-stepped groove  21 ,  21 ′, fashioned in the largest diameter portion  19  of the body  11 . Other arrangements of bolts and grooves may be made to the tool body without departing from the spirit of the invention made. 
     FIG. 3 further more clearly demonstrates the angle of the eccentric support spindle  20  from a normal (perpendicular) to the longitudinal axis of the tool. In prior art hole opener devices, the angle between the cutter axis and a plane perpendicular to the longitudinal axis of the tool supporting was approximately 30°; however, in the present device the angle of the spindle  20  to a perpendicular normal to the body  11  is approximately 20° or less. This lower angle requires less material be removed from the body to allow free rotation of the cutter. This additional material strengthens the overall body leading to longer service life and fewer failures in the field. 
     FIG. 4 is a partial schematic description of the end view of the hole opener with the smaller cutter shell bodies of FIG.  1 . This view clearly shows the dihedral shape of the cutter faces and the profile of the cutter in the hole. The profile of the hole opener  10  from the end demonstrates that the flow of drilling and fluids is not restricted with bracing or support for cutters permitting the free flow of drilling fluid and cuttings from the cutting face back along the periphery of the hole opener body  11  in the well bore annulus. 
     FIG. 5 is a similar schematic view of the end of FIG. 2 showing the larger cutter shells on the same hole opener body as FIG. 1 for opening a larger hole. Both FIG.  4  and FIG. 5 are shown without the tungsten carbide buttons shown in FIGS. 1,  2 , and  3 . As the cutter shells are enlarged the flow area around the cutter body is increased because the support arm only increase relative to the size of the cutter attached and does not encroach upon the fluid passage for the larger hole sizes. 
     FIG. 6 is a side view of a hole opener for use in large diameter holes, which functions in the same manner as the smaller diameter hole openers shown in FIGS. 1,  2  and  3 . A spindle block support gusset  119  is permanently attached to tubular body  111  and spindle block  117  is affixed to said gusset. Threaded pins  112  and threaded boxes  114  are again provided to permit connection of the hole opener  100  in the drill string. The spindle support block provides the attachment support for socket head cap screws  65 ,  66 , and  67  to attach the support arm body  60  identical to that used in either FIGS. 1 or  2 . The cutter shell may be changed in a similar manner to go from a smaller diameter hole with hole opener  100  to a larger diameter hole by easily changing the support arm, journal and cutter shell as described herein. 
     Adjacent each spindle block support gusset, a pilot guide gusset  118  supporting a fluid spout  150 , jetting nozzle holder  152  and jetting nozzle  153  may be permanently attached to the body of the hole opener permitting fluid communication from the longitudinal passage formed through the body  111  of the hole opener to provide means for carrying the cuttings from the cutters up the periphery of the body  111  through the annulus of the well bore (not shown). The pilot guide gusset may be hard faced to prevent wear in a manner well known to the drilling trades such as shown in  121 . 
     FIG. 7 shows an end view of the large diameter hole opener  100  with threaded box  114  at the center and disclosing the preferred arrangement of the three spindle support block gussets  119 ,  119 ′ and  119 ″ on which is affixed the spindle support block  117  into to which is attached the spindle support arms which provide engagement with the journals and cutters on said journals. Adjacent each of the three cutter support spindle blocks are the three fluid communication ports  150  with nozzle holder  152  and nozzle  153  supported on their respective pilot guide gussets  118 ,  118 ′ and  118 ″. Each of the support gussets may be connected by support gussets  120  to provide additional lateral support for the gussets. 
     FIG. 8 is a view of the preferred embodiment of the hole opener with the support arms removably connected to the larger diameter portion  19  of body  11  by pins  68 ,  68 ′, and  68 ″. As may be more clearly seen from cross-sectional view shown in FIG. 11, pin  68  is inserted in the enlarged portion  19  of body  11  through passage intersecting the stair-stepped groove  21 . Pin  68  is formed by any material of sufficient strength to secure arm  30 ′ in said groove  21  in a manner well known to those skilled in the art of manufacture of drilling equipment. A cap head bolt  69  is inserted in a slot  69 ″ formed in said body  19  to secure said pin in said body. A passage  69 ′ is provided on the opposite side of body  19  of lesser diameter than the passage provided for the pin  68  to permit the knock-out removal of the pin by an operator to remove or change the cutter arm  30 ′. As may be readily appreciated from FIG. 8, three pins are disclosed to hold the cutter arm in the stair stepped groove. Greater or lesser number of pins may be formed in the enlarged portion  19  of the tool body  11  to accommodate differing service requirements and drilling or hole enlarging environments. 
     In FIGS. 8 and 9, respectively, cutter arm  30 ′ and  60 ′ support cutter journals  28  and  70  and cutter bodies  25  and  80  in the same manner and operate in the same manner as the hole opener disclosed in FIGS. 1 and 2. The pins  68 ,  68 ′ and  68 ″ which are used to secure the cutter arms on the body in FIG. 8 are an alternative and preferred methods of attachment to the cap head bolts of FIG. 1 and 2. 
     FIG. 10 is an expanded view of spindle support arm  60 ′ mounted on the expanded portion  19  of body  11  (as in FIGS. 1 and 2) with a larger cutter  80  and journal body  70  to permit a larger diameter hole to be enlarged utilizing the same tubular body  11 . 
     It may be appreciated that the cutter support arm of each FIGS. 1,  2 ,  3 ,  7 ,  8 ,  9  and  12 , may be attached in a number of ways to the tubular body (or to the spindle support block of FIG. 7 and 12) without departing from the disclosure and intent of the present invention. For example, the pins  68 ,  68 ′ and  68 ″ could have alternatively been bolts or cap head screws with locking bolts or cap head screws. Additionally, the proximal end of the cutter support spindle might be affixed in a recess provided in the body  11  and either pinned or bolted by one or more screws onto the surface of the expanded body surface  19 . 
     In FIG. 13, an alternative embodiment of the cutter support arm connection is disclosed. Body  19  is tapped to provide threads at  150  for seating cap head screws  168 . A cap head screw  168  is inserted in the body  19  and through the hole machined into the proximal end of the cutter support arm  30 ′ and into the threaded body portion  150 . The cap head screw  168  seating in the threads  150  provides additional support for the cutter arm assembly and lessens the chance of fatigue failure from movement of the arm in the body. A smaller cap head screw  69  is seated adjacent the head of the cutter arm support cap head screw  168  to prevent loosening of the cap head screw  168  during operation. 
     FIG. 14 shows an alternative embodiment of the opener in which the body  19  is provided with a recess  23  into which is fitted the proximal end of the cutter body journal  70 . The profile shown in FIG. 14 provides rigidity and support for the journal  70  and allows the load placed on the cutter to be more evenly distributed to the body  19 . A cross-sectional view in FIG. 14 a  shows the spatial relationship of the spindle  20 , the non-concentric recess  23 , and the upraised surface  17  against which the proximal end of the journal  20  is seated and supported off of the surface of groove  21 . The recess prohibits the movement of the journal which is urged into movement by the movement of the cutter shell around the center post or spindle  20  of the profile thereby reducing the wear on the journal surfaces which mate with the enlarged portion  19  of the opener body  11  and increasing the life of the journal  70 . In this alternative embodiment, the journal body provides a longitudinal pathway through and is fitted with a grease plug  71  and grease nipple  72  in a manner well known to those in the industry, which provides a grease reservoir to provide lubrication during operation. The proximal end of the journal body  70  is fitted with a slotted retainer sleeve  73 , which prevents the bearing plug  24  in the body of the journal  70 , while at the same time allowing communication of grease from the reservoir to the bearing race. 
     After the cutter body  80  and journal  70  are assembled and mounted on the spindle  20  and secured by cutter arm  60 , grease is injected through the nipple  72  and into the reservoir between the floating grease plug  71  and the top of the spindle  20 . The distal end of the cutter support arm  60  is machined to provide a path for a standard grease gun, in a manner well known to those in the industry. The floating grease plug  71  is assembled with a seal  73  which fits in a groove provided on the surface of the plug  71 , providing sealing engagement of the floating grease plug  71  with the interior surface of the journal body  70 . Grease is retained within the reservoir and bearing surfaces by seal  73 ′ seated in a groove on the inner periphery of journal body  70 , which seals against the exterior surface of spindle  20 . Seals are also provided for grooves machined on the exterior surface of the journal body  70  to prevent ingress of drilling fluid into the bearing surfaces in a manner well known to those in this industry. 
     Grooves are provided in the journal and bearing race to allow lubrication to occur during operation. The floating grease plug  71  balances the pressure acting on the grease reservoir and the bearing surfaces. As hydrostatic pressure builds against the seal surfaces around the bearings a proportionate pressure moves the floating grease plug  71  down the reservoir to balance the pressure on the interior of the reservoir and bearing surfaces. As the volume of lubricant changes during operation of the cutter, the equalizing pressure also forces the lubricant from the reservoir and around the bearings thereby extending bearing life. 
     These lubrication features may be used on hole openers with either cap headed screw as described in FIGS. 1,  2 ,  3 ,  6 , or with pins or screw supports as described in FIGS. 8,  9 ,  10 , and  12 . 
     The present invention permits multiple hole sizes to be worked with one body. The support arm arrangement provides a safe, expedient means for changing the size of the hole sought to be enlarged without significant loss of time. The pin, which supported the spindle of the cutter found in many prior art devices, has been eliminated and the journal, which carries the cutter shell, is supported on both ends minimizing the bending moment associated with prior hole opener devices. The interchangeability of cutter support arms provides an efficient economic means for using a single tool for a variety of hole sizes.