Abstract:
A tree stump removal device is disclosed. The device includes an annular housing having cutters attached thereto. A method of removing a tree stump is disclosed that includes lowering a tree stump removal device into the ground surrounding the tree stump to severe some or all of the horizontal roots extending from the tree stump.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to tree stump removal devices. It relates more particularly to a tree stump removal device that severs the surrounding root system from a stump. 
       BACKGROUND OF THE INVENTION 
       [0002]    It has long been a problem to remove the remaining tree stump from the ground once the tree trunk has been severed there from. This problem exists for both professional tree services including orchardists, foresters and landscapers as well as the everyday homeowner. Present stump removal methods are costly and most often remove the tree stump without removing the roots. Another disadvantage of present methods is that they often disturb a large area of soil around the tree stump. 
         [0003]    The present disclosure is directed to overcoming one or more of the problems set forth above. 
       SUMMARY OF THE INVENTION 
       [0004]    The present disclosure relates to a tree stump removal device including a tubular body having a predetermined length extending from a first end to a second end, a cap attached to the first end, and cutters connected to the second end of the tubular body. The cutters may be integral with the second end of the tubular body or may be mechanically attached to the second end of the tubular body. The cap includes a releasable coupling that can be attached to a power rotational device to operate the tree stump removal device. 
         [0005]    The present disclosure further relates to a tree stump removal device including a tapered tubular body comprising a length extending from a first end to a second end, a cap removably attached to the first end, and cutters connected to the second end. 
         [0006]    The present disclosure further relates to a method of tree stump removal including cutting a circular slot with a tree stump removal device around a tree stump to a predetermined depth into ground around the tree stump. 
         [0007]    One advantage of the present disclosure is to provide an improved tree stump removal device that severs all or some of the roots horizontally extending from the tree stump. 
         [0008]    Another advantage of the present disclosure is to provide a tree stump removal device that is simple to operate and economical to manufacture. 
         [0009]    Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective view of an exemplary embodiment of a tree stump removal device according to the invention. 
           [0011]      FIG. 2A  is a perspective view of another embodiment of a tree stump removal device shown disassembled. 
           [0012]      FIG. 2B  is a perspective view of the tree stump removal device shown in  FIG. 2A  disassembled. 
           [0013]      FIG. 3A  is a perspective view of another embodiment of a tree stump removal device shown disassembled. 
           [0014]      FIG. 3B  is a perspective view of a partial section of  FIG. 3A . 
           [0015]      FIG. 4A  is a perspective view of another embodiment of a tree stump removal device according to the invention. 
           [0016]      FIG. 4B  is a partial perspective view of a bottom portion of the tree stump removal device of  FIG. 4A . 
           [0017]      FIG. 4C  is a partial sectional view of a bottom portion of the tree stump removal device of  FIG. 4A . 
           [0018]      FIG. 4D  is a partial perspective view of a bottom portion of another embodiment of a tree stump removal device according to the invention. 
           [0019]      FIG. 5A  depicts an embodiment of the present invention depicting a cutter portion body with notches for accepting a cutter assembly. 
           [0020]      FIG. 5B  depicts a bottom view of the cutter portion body of  FIG. 5A  viewed from the bottom. 
           [0021]      FIG. 6A  depicts a side view of a cutter holder as part of the cutter assembly. 
           [0022]      FIG. 6B  depicts a front view of the cutter holder of  FIG. 6A . 
           [0023]      FIG. 7  depicts a cutter insert as part of the cutter assembly. 
           [0024]      FIG. 8  depicts a cutter assembly comprising the cutter insert assembled to the cutter holder to form a cutter assembly and the cutter assembly assembled to the cutter portion body of the tree stump removal device. 
           [0025]      FIG. 9  represents a method for removing a tree stump having a diameter larger than the diameter of the tree stump removal device according to the invention. 
       
    
    
       [0026]    Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0027]      FIG. 1  shows an exemplary embodiment of a tree stump removal device  100  according to the invention. As can be seen in  FIG. 1 , the tree stump removal device  100  includes a body portion  110  and a top portion or cap  120 . The body portion  110  includes a housing portion  111  and a cutting portion  112 . 
         [0028]    The housing portion  111  may have a generally tapered tubular shape having a length L extending from a top end  113  to a bottom end  114 . The housing portion  111  has a first outside diameter OD1 at the top end  113  and a second outside diameter OD2 at the bottom end. The housing portion  111  further has a first inside diameter ID1 at the top end and a second inside diameter ID2 at the bottom end  114 . ID1 is greater than ID2. The change in diameter from ID1 to ID2 is proportional to L. In one embodiment, the ratio of decreasing diameter to length is between about 0.125:12 to about 2.0:12. In another embodiment, the ratio of decreasing diameter to length is between about 0.25:12 to about 1.0:12. In yet another embodiment, the ratio of decreasing diameter to length is between about 0.5:12 to about 0.75:12. In yet another embodiment, the housing portion  111  may have a constant internal diameter over L. In yet another embodiment, the housing portion  111  may have a discontinuous internal diameter over L. The housing portion  111  may be formed of a metal, metal alloy or composite, such as, but limited to ferrous or nonferrous metals, and composites, such as, but not limited to a steel or aluminum alloy. 
         [0029]    The housing portion  111  further includes tabs  115 . The tabs  115  include openings  116  for receiving fasteners  117 . In this exemplary embodiment, the tabs  115  are joined to the housing portion  111 . The tabs  115  may be joined to the housing portion  111  by brazing, welding or other metal joining technique. In another embodiment, the tabs  115  may be an integral part of the housing portion  111 . As used herein, the term “integral part” and “integral to” means that the portion is a part of the initial forming of the part. In yet another embodiment, the housing portion  111  does not include tabs  115 , and the openings  116  are integral to the housing portion  111 . The housing portion  111  includes three tabs  115 . In another embodiment, the housing portion  111  may include two or more tabs  115 . The fasteners  117  may be, but is not limited to, pin, bolts, screws or other similar devices. 
         [0030]    The cutting portion  112  is fixed to the housing portion  111 . The cutting portion  112  includes a cutting portion body  112   a  and cutters  118 . The cutting portion  112   a  may be fixed to the housing portion  111  by a metal joining technique, such as, but not limited to brazing and welding. In another embodiment, the cutting portion  112   a  may be integral to the housing portion  111 . The cutting portion  112  may be formed of the same or different material as the main portion  114 . The cutting portion  112  has a same or approximately the same second inside diameter ID2 as the housing portion  111  at bottom end  114  of the housing portion  111 . 
         [0031]    In this exemplary embodiment, cutters  118  may be cutting teeth formed into the cutting portion body  112   a.  The cutters  118  may be integrally formed into the cutting portion  112  by cutting, grinding, machining or other metal forming method. In another embodiment, cutters  118  may be projections, inserts, attachments, or other frictional devices formed as an integral part of the cutting portion body  112   a.  In yet another embodiment, the cutters may be mechanically fastened to the cutting portion body  112   a.  In still another embodiment, the cutters may be integrally attached to the cutting portion body  112   a  by metallurgically joining the cutting portion to the cutting portion body  112   a.  For example, a cutting portion may be metallurgically joined by welding a separate cutting insert to the cutting portion body  112   a.  Alternatively, the cutting portion also may be provided metallurgically by hard facing projections in the cutting portion body with a wear resistant hard facing material such as stellite. In an embodiment, cutters  118  may be joined to the cutting portion body  112   a  by a material joining technique, such as, but not limited to brazing or welding. 
         [0032]    In one embodiment, the cutters  118  are directional, or in other words, pitched to cut in a particular rotational direction R of the tree stump removal device  100 . In another embodiment, the cutters  118  may be bi-directional. 
         [0033]    The cutters  118  include a cutting face or surface  118   a.  In one exemplary embodiment, the cutting surface  118   a  is the exposed surface of the cutters  118 . In another embodiment, the cutting surface  118   a  may be hardfaced with an appropriate hardfacing material. In another embodiment, the cutting surface  118   a  be a surface of an insert, bit, or other attachment, that is attached, mechanically fastened or otherwise joined to the cutters  118 . 
         [0034]    The cap  120  includes a cap body  120   a  and a coupling  130 . The cap body  120   a  may include optional openings (not show, but shown as  460  in  FIG. 4 ). The cap  120  is capable of joining to the housing portion  111 . The cap  120  has an outside diameter OD3. In this exemplary embodiment OD3 is approximately equal to OD1. In another embodiment, OD3 may be larger or smaller than OD1. For example, OD3 may be approximately equal to ID1. The cap  120  includes cap tabs  115 A that correspond to tabs  115 . The cap tabs  115 A have openings  116 A that correspond to openings  116 . In one embodiment, the openings  116   a  may be threaded. In such a manner openings  116  and  116 A are aligned when the cap  120  is joined to the housing portion  111 . The cap tabs  115 A may be joined to the cap  120  by brazing, welding or other metal joining technique, or the cap tabs  115  may be an integral part of the cap  120 . In yet another embodiment, the cap  120  is joined to the housing portion  111  by welding, brazing, or other metallurgical bonding technique, and no mechanical fastener is required. 
         [0035]    The coupling  130  is attached to the cap body  120   a.  In one embodiment, the coupling  130  is joined to the cap body  120   a  by a metal joining technique, such as, but not limited to, brazing or welding. In another embodiment, the coupling  130  is integral to the cap body  120   a.  The coupling  130  includes a recess  132  and an opening  133  through the coupling  130  that traverses the recess  132 . In this exemplary embodiment, the coupling  130  is a standard power take-off (PTO) coupling. In another embodiment, the opening  133  receives a pin (not shown) for temporarily locking a PTO in the recess  132 . The power take-off coupling may be connected to a tractor or drive of a vehicle or power equipment. In another embodiment, the coupling  130  may be a coupling capable of releasably connecting to a rotational and/or vibrational mechanical power device, such as, but not limited to a power take-off, drill or other power rotational device. 
         [0036]      FIGS. 2A and 2B  shows a another embodiment of a tree stump removal device  200  according to the invention. As can be seen in  FIG. 2 , the tree stump removal device  100  includes a body  210  and a top portion or cap  220 . The body  210  includes a housing or housing portion  211  and a cutting portion  212 . The housing portion  211  includes a first portion  211   a  and a second housing portion  211   b.  The first housing portion  211   a  and second housing portion  211   b  have a groove  251  and tongue or projection  252 , respectively, for aligning and stabilizing the first and second housing portions  211   a,    211   b  during assembly. The first and second housing portions  211   a,    211   b  include openings  216  for receiving fasteners  253 . In another embodiment, the openings  216  may be omitted. 
         [0037]    When assembled as shown in  FIG. 2A , the housing portion  211  has a generally tapered tubular shape having a length L extending from a top end  213  to a bottom end  214 . The housing portion  211  has a first outside diameter OD1 at the top end  213  and a second outside diameter OD2 at the bottom end  214 , that are similar to those shown in  FIG. 1 . The housing portion  211  further has a first inside diameter ID1 at the top end and a second inside diameter ID2 at the bottom end  214  similar to those shown in  FIG. 1 . In this exemplary embodiment, ID1 is greater than ID2. The change in diameter from ID1 to ID2 is proportional to L. In one embodiment, the ratio of decreasing diameter to length is between about 0.125:12 to about 2.0:12. In another embodiment, the ratio of decreasing diameter to length is between about 0.25:12 to about 1.0:12. In yet another embodiment, the ratio of decreasing diameter to length is between about 0.5:12 to about 0.75:12. In yet another embodiment, the housing portion  211  may have a constant internal diameter over L, or in other words ID1 is equal to ID2. In yet another embodiment, the housing portion  211  may have a discontinuous internal diameter over L. The housing portion  211  may be formed of a metal, metal alloy or composite, such as, but limited to ferrous or nonferrous metals, and composites, such as, but not limited to a steel or aluminum alloy. 
         [0038]    The cutting portion  212  is attached to or integral with and extends from the bottom end  214  of the housing portion  211 . The cutting portion includes a slot  264  that receives a corresponding protrusion  265  of the main portion  211  to fasten or join the cutting portion  212  and body portion  211  together. In another embodiment and cutting portion  212  and main portion  211  may be joined by a fastener, such as, but not limited to a pin, bolt, or clip. 
         [0039]    The cutting portion  212  includes a cutting portion body  212   a  and cutters  218 . The cutters  218  may be referred to as cutting teeth. The cutting portion  212  has a same or approximately the same second inside diameter ID2 as the bottom end  214  of the housing portion  211 . In this exemplary embodiment, the cutters  218  are formed into the cutting portion  212 . The cutters  218  may be formed into the cutting portion  212  by cutting, grinding or other metal forming method. In this embodiment, the cutters  218  are directional, or in other words, pitched to cut in a particular rotational direction R of the tree stump removal device  200 . In another embodiment, the cutters  218  may be bi-directional. In another embodiment, the cutters  218  may be hardfaced with an appropriate hardfacing material. In another embodiment, the cutters  218  may be inserts or bits joined to the cutting portion  212  by a metal joining technique, such as, but not limited to, brazing or welding. 
         [0040]    The cutters  218  include a cutting face or surface  218   a.  In this exemplary embodiment, the cutting surface  218   a  is the exposed surface of the cutters  218 . In another embodiment, the cutting surface  218   a  may be hardfaced with an appropriate hardfacing material. In another embodiment, the cutting surface  218   a  be a surface of an inserts or the like that are attached, fastened or otherwise joined to the cutters  218 . 
         [0041]    The cap  220  includes a cap body  220   a,  a coupling  230 , and an insertion portion  282 . The cap  220  is capable of joining to the main portion  211 . The insertion portion  282  includes holes  283  that correspond to openings  216 . The holes  283  are threaded to receive a threaded fastener  253 , such as, but not limited to a bolt and screw, to releasably fasten the first and second main portions  211   a,    211   b  to the cap  220 . In another embodiment, the first and second main portions  211   a,    211   b  may be releasably attached to the cap  220  by any suitable releasable fastener including, but not limited to, tabs, pins, and couplings. The insertion portion  282  has an outside diameter OD3B. In this exemplary embodiment OD3 is approximately equal to the interior diameter ID1 ( FIG. 1 ) of the assembled main portion  213  at the top end  213 . 
         [0042]    The coupling  230  is attached to the cap body  220   a.  In one embodiment, the coupling  230  is joined to the cap body  220   a  by a metal joining technique, such as, but not limited to, brazing or welding. In another embodiment, the coupling  230  is integral to the cap body  220   a.  The coupling  130  includes a recess  232  and an opening  233 . In this exemplary embodiment, the coupling  130  is a standard power take-off (PTO) coupling. In another embodiment, the opening  233  receives a pin (not shown) for temporarily locking a PTO in the recess  232 . The power take-off coupling may be connected to a tractor or drive of a vehicle or power equipment. In another embodiment, the coupling  230  may be a coupling capable of releasably connecting to a rotational device, such as, but not limited to a rotational mechanical power device, such as, but not limited to a power take-off, a drill or other power rotational device. The coupling  230  may be joined to the cap body  220   a  by brazing, welding or other metal joining technique, or the coupling  230  may be an integral part of the cap  220 . 
         [0043]      FIGS. 3A and 3B  shows another embodiment of a tree stump removal device  300  according to the invention. As can be seen in  FIGS. 3A and 3B , the tree stump removal device  300  includes a body portion  310  and a top portion or cap  320 . The body  310  includes a housing portion  311  and a cutting portion  312 . The housing portion  311  has a preselected length L extending from a top end  313  to a bottom end  314 . The main portion  311  includes slots  311   a  that pass through to an interior space  391  defined by the main portion  311 . In this embodiment, the main portion  311  includes three slots  311   a.  In another embodiment, the main portion  311  may include one or more slots  311   a.    
         [0044]    The housing  311  further includes tabs  315  having openings  316  for receiving fasteners  317 . In this exemplary embodiment, the housing  311  has a constant internal diameter ID1′ over the length L of the housing portion extending from the top end  314  to the bottom end  314 . In another embodiment, the housing  311  may have a discontinuous internal diameter ID1′ over L. In yet another embodiment, the housing  311  may have a decreasing, tapered internal diameter from the top end  313  to the bottom end  314 . 
         [0045]    The cutting portion  312  is joined to the bottom end  214  of housing  311 . In this exemplary embodiment, the cutting portion  312  are projections or cutters that have been formed from a portion of the housing  311 . In one embodiment, the cutting portion  312  may be hardfaced. In this exemplary embodiment, the cutting portion  312  includes three cutters (one cutter hidden in rear). In another embodiment, the cutting portion  312  may include one or more cutters. In another embodiment, the cutting portion  312  may be joined by a metal joining technique such as, but not limited to brazing or welding. In one embodiment, the cutting portion  312  includes a cutting portion body joined to the main body  311  to which teeth or cutters are joined. 
         [0046]    The cap  320  includes a cap body  320   a,  a coupling  330 , and a core screw  340 . The cap  320  is capable of joining to the housing  311 . The cap body  320   a  includes slots or openings  322  for receiving tabs  315  and holes or fastener openings  316   a  for receiving a fastener  317 . The fastener  317  may be a bolt, pin, hitch pin, or other engaging device for securing the cap  320  to the body  310 . The fastener  317  may be threaded or unthreaded. The cap body  320  includes openings  322  radially distributed at different radius from the centerline or vertical axis Z of the tree stump removal device  300 . In such a manner, the cap  320  may be releasably attached to a body  310  of various diameters. 
         [0047]    The coupling  330  includes a recess  332  and an opening  333 . In this exemplary embodiment, the coupling  330  is a power take-off (PTO) coupling. In another embodiment, the opening  333  receives a pin (not shown) for temporarily locking a PTO in the recess  332 . The power take-off coupling may be connected to a tractor or drive of a vehicle or power equipment. In another embodiment, the coupling  330  may be a coupling capable of releasably connecting to a rotational device, such as, but not limited to a rotational mechanical power device, such as, but not limited to a power take-off, drill or other power rotational device. The coupling  330  may be joined to the cap body  320   a    320  by brazing, welding or other metal joining technique, or the coupling  330  may be an integral part of the cap  320 . 
         [0048]    The core screw  340  is received in the opening  332 . The core screw is releasably attached within the opening  332  by a fastener  317   b  received through openings  333   b  and  333   c.  The fastener may be a bolt, pin, hitch pin, or other engaging device for releasably engaging the core screw  340  to the coupling  330 . In another embodiment, the core screw  340  may be omitted. In yet another embodiment, the core screw  340  and the opening  333   b  may be omitted. The core screw  340  includes a threaded portion  340   a  for releasably engaging a material, such as a tree stump, in the interior of the main portion  311   a.  In such a manner, the core screw  340  may engage and extract a tree stump from the ground after the cutting portion  312  cuts and/or severs roots extending from the tree trunk. 
         [0049]      FIG. 4A  illustrates another exemplary embodiment of a tree stump removal device  400 . As can be seen in  FIG. 4A , the tree stump removal device  400  includes a body portion  410  and a top portion or cap  420 . The body portion  410  includes a housing portion  411  and a cutting portion  412 . The housing portion  411  has a generally cylindrical tubular shape having a length L extending from a top end  413  to a bottom end  414 . The body portion  411  has an outside diameter OD1* and an inside diameter ID1*. 
         [0050]    The housing portion  411  includes a first housing portion  411  a and a second housing portion  411   b.  The first and second housing portions  411   a,    411   b  are joined by a material joining technique, such as, but not limited to welding or brazing. In another embodiment, the first and second housing portions  411   a,    411   b  may be joined by mechanical fastening. In another embodiment, the housing portion  411  is a single, unitary body. In yet another embodiment, the housing portion  411  is formed to two or more body portions. The housing portion  411  further includes openings  416  for receiving fasteners  417 . In this exemplary embodiment, the housing portion  411  includes three openings  416 . In another embodiment, the housing portion  411  may include two or more openings  416 . The fasteners  417  may be, but is not limited to, a pin, bolt or screw. The housing portion  411  may be formed of a metal, metal alloy or composite, such as, but limited to ferrous or nonferrous metals, and composites. For example, the housing portion  411  may be formed of steel or aluminum alloy. 
         [0051]    The cap  420  includes a cap body  420   a  and a coupling  430 . The cap  420  is capable of joining to the housing portion  411 . The cap  420  has an outside diameter OD3*. In this exemplary embodiment OD3* is approximately equal to or slightly less than ID1* so that the cap body  420   a  may be at least partially received in the housing portion  411 . The cap  420  includes openings  416   a  that correspond to openings  416  so as to further receive fasteners  417 . In such a manner openings  416  and  416 A are aligned when the cap  420  is joined to the housing portion  411 . In another embodiment, the openings  416   a  may be threaded. The cap  420  may further be attached to the housing portion  411  by a metal joining technique, such as, but not limited to brazing or welding. In another embodiment, the openings  416  and  416   a  may be omitted, and the cap  420  may be joined to the housing portion  411  by a metal joining technique, such as, but not limited to brazing or welding. 
         [0052]    The coupling  430  is joined to the cap body  420   a.  In one embodiment, the coupling  430  is joined to the cap body  420   a  by a metal joining technique, such as, but not limited to, brazing or welding. In another embodiment, the coupling  430  is integral to the cap body  420   a.  The coupling  430  includes a recess  432  and an opening  433 . The opening  433  traverses through the coupling  430  and recess  432 . The opening  433  may receive to pin, bolt, or other fastener. In this exemplary embodiment, the coupling  430  is a standard power take-off (PTO) coupling. In an embodiment, the recess  432  is configured to receive a standard PTO (not shown), and the opening  133  receives a pin, bolt or other fastener (not shown) for temporarily coupling the PTO to the tree stump removal device  400 . The power take-off coupling may be connected to a rotational drive of a tractor, vehicle, post hole drill, drill or other power equipment. 
         [0053]    Referring to  FIGS. 4A ,  4 B and  4 C, the cutting portion  412  includes a cutter portion body  414  and cutters  418 . The cutter portion body  414  includes an insert portion  414   a.  The insert portion  414   a  is received in and along the inside wall  411   a  of housing portion  411 . The cutter portion  412  is metallurgically joined to the housing portion  411  by a joining technique, such as, but not limited to brazing or welding. In another embodiment, the cutter portion  412  is mechanically fastened to the housing portion by a fastener, such as, but not limited to a pin, bolt, screw or clip. 
         [0054]    In this exemplary embodiment, the cutter portion  412  includes eight cutters  418 . In another embodiment, the cutter portion  412  may include one or more cutters  418 . The cutters  418  include a cutter body  418   a  and a cutter insert  418   b.  The cutter body  418   a  is machined into the cutting portion  412 . 
         [0055]    The cutter insert  418   b  is formed of a cutter material. In one embodiment, the cutting insert  418   b  is formed of a hardened material. In one embodiment, the cutting insert  418   b  is a tungsten carbide insert. In another embodiment, the cutting insert  418   b  may be formed of a cermet, ceramic, metal, metal alloy or any combination thereof. The cutting insert  418   b  includes a through hole  418   c  through which a mechanical fastener (not shown) is inserted joining the cutting insert  418   b  to the cutter body  418   a.  The mechanical fastener may be a bolt, screw, or other like device. In one embodiment, the cutting insert  418   b  is releasably attached to the cutter body  418   a,  so the cutting insert  418   b  may be replaced when worn or broken. In another embodiment, the cutting insert  418   b  may be joined to the cutter body by a metallurgical bond, mechanical fastener, or combination thereof. In yet another embodiment, the cutting insert  418   b  is continuous part of a cutter  418 , or in other words, the cutters  418  are a single, unitary body. In yet another embodiment, the cutter insert  418   b  may be omitted, ant the cutters  418  may be hard faced with an appropriate hard facing material. 
         [0056]      FIG. 4D  illustrates another embodiment of the cutter portion  412  and cutters  418 . As can be seen in  FIG. 4D , the cutter portion  412  includes a slot  412   a  for receiving cutters  418 . The cutters  418  are metallurgically joined to the cutter portion  412  by a bonding technique, such as, but not limited to brazing or welding. In another embodiment, the cutter  418  is received in a housing slot  411   b  and joined to the cutting portion by a metallurgical and or mechanical joining technique. The mechanical joining technique may use a mechanical fastener, such as, cut not limited to a screw, bolt or pin. 
         [0057]    The cutters  418  include a cutter body  418   a  and a cutter insert  418   b.  The cutter body  418   a  may be formed of metal, metal alloy, ceramic, or composite. In one embodiment, the cutter body  418   a  may be formed of a hardened steel or aluminum. In one embodiment, the cutter insert  418   b  is tungsten carbide composite. In another embodiment, the cutter insert  418   b  may be formed of a cermet, ceramic, composite, metal, metal alloy or any combination thereof. 
         [0058]    In an embodiment of a method of operating the tree stump removal device  400 , the tree stump removal device  400  is coupled via coupling  430  to a mechanical rotary device (not shown), such as, but not limited to, a power take off of an industrial machine, such as, but not limited to, a tractor, post hole driller, drill, or other like device. In one embodiment, the tree stump removal device  400  is selected to have the main portion  411  having an inside diameter greater than the diameter of a tree stump selected for removal. 
         [0059]    The tree stump removal device  400  is then place over the tree stump. The rotary mechanical device is switched on so as to rotate the tree stump removal device  400  about the Z axis. The tree stump removal device  400  is then lowered towards the ground. The tree stump removal device  400  is continued to be lowered as the cutters  418  engage the ground and/or tree roots. The tree stump removal device  400  is lowered until the cutting portion  412  enters the ground to a desired depth. The desired depth is selected to sever some, most, or all of the roots of the stump horizontally extending therefrom. The tree stump removal device  400  is then raised from the desired depth and the severed tree stump is removed. In one embodiment, the tree stump is partially retained in the main portion  411  when the tree stump removal device  400  is raised. In another embodiment, tree stump removal device  400  includes a core screw  340  ( FIG. 3A ), and the tree stump is engaged by a core screw  340  and is partially retained in the main portion  411  when the tree stump removal device  400  is raised. In yet another embodiment, the tree stump remains in the ground after the tree stump removal device  400  has been raised, and the tree stump may be removed from the ground or left to decay in the ground. 
         [0060]      FIGS. 5-9  depict a preferred embodiment of the tree stump removal device of the present invention.  FIG. 5A  depicts only the cutter portion body  514  of the body portion of the preferred embodiment, as the cap portion and the housing portion may assume any of the configurations depicted in the previously described embodiments depicted in  FIGS. 1-4 . In this embodiment, cutter portion body is integral with body portion  410 . Cutter portion body  514  may be attached to housing portion  411  metallurgically, as previously described, or it may be machined as part of the body portion, forming for example a body portion fabricated as a single cylindrical piece. Cutter portion body  514  as shown in  FIG. 5A and 5B  does not include any cutter assemblies or cutter inserts. Cutter portion body  514  includes a plurality of notches  535  machined into its lower circumference. The notches are formed in the circumference a distance of 1-d from the bottom surface of cutter portion body. While a plurality of notches  535  may be formed in cutter portion body  514 , three notches are preferred, as shown in  FIG. 5B  which is view of cutter portion body  514  from the bottom looking toward the cap. The notches may span any circumferential distance c. Also depicted in  FIG. 5A  is a radially oriented aperture  539 . One aperture  539  is positioned above each of the plurality of notches  535  formed in cutter portion body  514 . 
         [0061]    Referring now to  FIGS. 6 and 7  are cutter holder and cutter insert  555 .  FIG. 6A  is a side view of cutter holder  545 .  FIG. 6B  depicts a front view of the cutter holder of  FIG. 6A . Cutter holder  545  includes a pair of arms  547  extending from a base  549 . Cutter holder has a length of 1 as shown in  FIG. 6A , while the arms extend a distance of d toward a cutter holder base  549 . The base thus has a size of 1-d which corresponds to the notch dimension 1-d depicted in  FIG. 5 , so that base matches the notch, fitting into notch  535 . Pair of arms  547  are separated by a distance t. Distance t corresponds to the thickness of the cutter portion body  514  which may vary from 100-500 mils (1/10-½ inch). Base  549  of cutter holder  545  further includes a countersink  551  which receives cutter insert  555 . Countersink  551  has a radius r (and a diameter of 2r). Radius r is less than (1-d)/2 or 2r is less than (1-d). [(1-d)-2r] is a dimension that represents a wall thickness y of the countersink, that is [(1-d)-2r]=2y. Countersink  551  further includes countersink aperture  553  which is threaded to receive a correspondingly threaded fastener. The preferred thickness of cutter portion body is about 0.25 inches. While the thickness of the cutter portion body may be reduced, as the thickness is reduced, the potential for damage to the cutter portion body due to deformation during tree stump removal increases. The thickness of the cutter portion body  514  may also be increased; however increasing its thickness, which increases rigidity, also increases weight, encumbering handling of the tree stump removal device. The dimensions are set forth as variables because the dimensions may have any physical sizes that meet these general parameters, and the invention should not be restricted to specific physical dimensions. 
         [0062]      FIG. 7  provides a view of cutter insert  555 .  FIG. 7  provides a perspective view of cutter insert  555 . It can be seen that cutter insert  555  is frustoconical in shape in the preferred embodiment. Cutter insert is dimensioned to fit into countersink  551  of cutter holder  545 . Cutter insert  555 , being frustoconical, has a major radius of r+y+e where e is a dimension no greater than 160 mils (0.160 inches) and a minor radius  576  less than r. Cutter insert  555  also includes a cutter aperture  563  corresponding to countersink aperture  553 , allowing a threaded fastener to be inserted through cutter aperture and threaded into countersink aperture  553 , thereby securing cutter insert  555  into countersink  551  of cutter holder. Since the minor radius of cutter insert  555  is less than r, the narrow end of cutter insert  555  fits into countersink  551  allowing cutter insert  555  to be secured within countersink  551  of cutter holder  545  by a fastener. The major radius of cutter insert  555  extends below cutter holder  545  by the dimension e, which is no greater than 160 mils, preferably no greater than 150 mils, and most preferably 50-125 mils. This dimension e represents the cutting edge of cutter insert  555 . When the cutting edge represented by e is greater than about 160 mils, it has been found that any binding that occurs during tree stump removal can result in distortion or bending of the body portion when a body portion and cutter portion body have the preferred thickness of ¼ inch. Of course, increasing the thickness of the body portion when the cutting edge extends beyond 160 mils can alleviate this problem, providing a thicker and stiffer tool, but with increased weight and decreased handleability. Although cutter insert  555  is described in its preferred embodiment as having a frustoconical shape, one skilled in the art would recognize that cutter insert  555  may also be fabricated in other shapes, such as but not limited to a cylindrical part having a plurality of radii, a first radii at one end being smaller than radius r and a second radius at the opposite end sized to r+y+e. Cutter insert  555  preferably comprises a carbide tool steel although it may comprise a hard-faced part, where the hard faced material is a wear resistant material. 
         [0063]      FIG. 8  depicts cutter insert  555  assembled to cutter holder  545 , and cutter holder assembled into a corresponding notch  535  of cutter portion body  514 . The plurality of notches  535 , which are radiused to correspond to the radius of the cutter portion body, slide over the cutter portion body  514  as one cutter holder  545  is assembled into each notch of the plurality of notches  535 . A second aperture  554  extending through arms  547  of cutter holder  545  align with aperture  5339  in cutter portion body  514 , allowing cutter assembly  575  comprising cutter insert  555  and cutter holder  545  to be secured to cutter portion body  514 . As can be seen from  FIG. 8 , cutting edge e of cutter insert  555  extends below cutter portion body  514 . Once assembled, the major diameter (twice the radius) of cutter insert edge extends below cutter portion body perpendicular to the direction of rotation of the tool by a distance e which, as discussed may extend up to 160 mils (0.160 inches) maximum. 
         [0064]    This preferred design is easy to assemble and disassemble. It allows for ready replacement of the cutter inserts  555  as they wear, the cutter inserts experiencing most of the wear, while the cutter holder  545  and cutter portion body  514  experience very little wear allowing them to be used until they experience wear, which may be indefinitely. Surprisingly, this design also allows for easy removal of the tree stump after it has been extracted. As the cut around the tree stump is made, severing side roots, debris and soil accumulates between the stump and the inner diameter of the tree stump removal tool, compacting as the tree stump removal tool rotates. After all side roots have been cut, the stump and the compacted debris and soil are captured within the inner diameter of the tree stump removal tool. The stump eventually rotates with the tree stump removal tool and causes loosening or breaking of any tap root that may be present. The stump (along with the debris and compacted soil) may then be lifted out of the ground. With this preferred design, the tree stump and compacted soil and debris captured within the tree stump removal tool are readily removed by shaking the tree stump removal tool. The soil and debris are held tightly within the inner diameter by one of arms  547  for each cutter holder, but soil and debris are readily removed adjacent arms  547  by shaking, ultimately resulting in release of the stump from the tree stump removal tool. 
         [0065]    Referring again to  FIG. 6A  and  FIG. 6B , the countersink  551  is shown centered into cutter holder  545 . One skilled in the art will understand that by slightly varying the dimensions of cutter holder  545 , countersink  551  can be fabricated so that it is not centered but biased, either to the right or to the left of the configuration shown in  FIG. 6 . Thus when assembled into notches  535 , the cutting edge of cutter insert may extend downward but instead of being centered, either biased more toward the inside diameter of cutter portion body  514  or biased more toward the outside diameter of cutter portion body  514 . 
         [0066]    In one preferred embodiment in which three cutter inserts  555  are assembled to three cutter holders, one cutter insert  555  is centered in a cutter portion body  514  configured as shown in  FIG. 8 , one is biased more toward the inside diameter of cutter portion body  514  and one is biased more toward the outside diameter of cutter portion body  514 . This embodiment provides a cut having a maximum kerf as compared to an assembly in which all cutter inserts  555  are oriented in cutter holders the same way. 
         [0067]    The present invention has been described as a tree stump removal device, the tree stump removal device having preselected diameters up to 24 inches, and preferably from one foot (12 inches) to two feet (24 inches) in diameter. Although the tree stump removal device is described as limited to maximum sizes having diameters up to 24 inches, this limitation is related to costs, as the costs increase with increasing tree stump removal device diameter. Also, the stresses increase with increasing diameter, making it more likely for the tree stump removal device to bend during operation should binding occur unless the thickness of the cylindrical portion of the tool is increased as previously noted. 
         [0068]    In many situations, a tree stump removal device is selected from among devices having a size range of the cutting diameter varies from 1-2 feet. A tree stump removal device with a cutting diameter larger than the cutting diameter of the tree stump, preferably with a cutting diameter about 2 inches larger than the diameter of the tree stump. As previously discussed, the tree stump removal device is comprised of a tubular body having a preselected length from a first end to a second end, the length generally being longer as the cutting diameter increases. A cap including a releasable coupling is attached to the first end of the tubular body of the tree stump removal device. Cutters are located at the second end of the tubular body opposite the releasable coupling. 
         [0069]    A power rotational device is provided for attachment to the releasable coupling. Preferably, the power rotational device is self-propelled and includes a power take-off. The invention envisions a device such as a tractor, a payloader or other similar self-propelled device that can power rotation. The power rotational device is attached to the coupling either before or after the tree stump removal device is aligned over the tree stump. The cutters overlap at least some soil or debris adjacent to the tree stump and when the selected cutting diameter is larger than that of the tree stump, the cutter completely overlaps the tree stump and is aligned over the adjacent soil or debris. 
         [0070]    Once power is applied, a circular slot is cut at least partially into the soil and debris surrounding the tree as the tree stump removal device is lowered. The tree stump removal device is lowered to a predetermined depth into the ground up to the preselected length of the tubular body, cutting any side roots emanating from the stump. As the tree stump removal device is lowered around the tree stump, debris such as cutting chips from any side roots and soil is captured and compacted within the inside diameter of the tubular body. This compacted soil and debris assists in maintaining the tree stump within the tree stump removal device as the device is lifted out of the ground by the power rotational device. After lifting the tree trunk out of the ground, it may be necessary to shake or otherwise vibrate the tree stump removal device to remove the stump and the compacted debris and soil from the inside diameter of the tubular body, as these are held in position by friction forces. Of course, before initiating any stump removal, the cutters should be examined for damage and to assure that they can provide the appropriate depth of cut. When the cutters are removable, cutters that do not pass the examination should be replaced when the cutters are mechanically removable. For metallurgically integrated cutters, the worn cutters should be cut off and new cutting inserts should be welded on, or new hard facing should be applied to the cutting surface. 
         [0071]    However, a tree stump removal device within the specified range, up to 24 inches, can be used to remove stumps that are larger than the their maximum inside diameter. This is illustrated in  FIG. 9 . In  FIG. 9 , the tree trunk is represented by the circle  906  having the largest diameter. Also shown in  FIG. 9  are five smaller circles  901 - 905 . Each of the smaller circles represents the diameter of a tree stump removal device, the diameter of the tree stump removal device being smaller than the tree diameter. In this example, the tree stump is removed in five cuts, the first cut being made with circle  901  and the subsequent cuts being made sequentially and represented by circles  902 ,  903   904  and  905 . With each cut, a portion of the stump is cut and a cut is made in the soil adjacent to the cut. If there are any side roots, they are cut by the tree stump removal device. In each cut, soil and debris are compacted within tree stump removal device. After each cut is made, the cut stump and compacted debris are removed from the tree stump removal device by shaking the tree stump removal device before the next cut is initiated. This process is repeated until the tree stump has been removed, or at least has been removed to the depth of the tree stump removal device. A tree stump removal device having a cutting depth of at least two feet in usually enough to remove most stumps. If the stump cannot be removed with a tree stump removal device with this cutting depth, this cutting depth is sufficient to allow soil to be placed into the cut so that grass or other ground cover may be planted. 
         [0072]    While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.