Abstract:
A method and an apparatus for truing the interface between an arrow shaft or insert and the arrow tip is provided. A squaring tool having a frame with at least one V-shaped channel supports an arrow shaft in parallel with the frame longitudinal axis. A cutting tool is mounted on the frame. A cutting surface of the cutting tool is perpendicularly aligned to both the tool frame longitudinal axis and the V-shaped channels. Each channel supports the arrow wherein an arrow longitudinal axis aligns in parallel with the frame longitudinal axis. The arrow is placed in the tool having the interface adjacent to the cutting surface and the assembly is rotated within the channels as the arrow shaft is translated against the cutting surface. The interface is cut by the cutting surface to perpendicularly align the interface with the arrow longitudinal axis.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application No. 60/358,227, filed on Feb. 20, 2002. The disclosure of the above application is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates generally to a method and apparatus to true archery arrows and more specifically to a method and apparatus to true either an arrow insert or the arrow end for subsequent mounting of an arrow tip in line with the longitudinal axis of the arrow. 
   BACKGROUND OF THE INVENTION 
   A modern arrow comprises several components, some of which are designed to be assembled and/or replaced by an archer with the intent of facilitating interchangeability or repair in a simple home workshop environment or, if need arise, in the field. One group of such components are 1) the arrow tip, 2) the arrow shaft and 3) the threaded insert that connects the arrow tip to the arrow shaft. 
   To achieve true flight, the longitudinal axis of the tip should be collinear with the longitudinal axis of the arrow shaft. Any deviation of the tip away from the longitudinal axis of the shaft must be minimized to prevent inadvertent arrow flight. An arrow is generally constructed having a hollow cylindrical inner diameter. A threaded insert is placed within the hollow center of the arrow shaft such that a face of the threaded insert is perpendicularly aligned to the longitudinal axis of the arrow shaft. The arrow tip is normally threaded onto or into the threaded insert and abuts the face of the threaded insert. A drawback of the conventional method of installing the threaded insert to the arrow shaft is that assembly is often done by the archer and includes an adhesive to join the threaded insert to the arrow shaft. The following situations are known to cause alignment problems: 1) the face of the threaded insert not being perpendicularly aligned to the centerline of the insert, 2) the combined misalignment of the threaded insert and arrow shaft joint, 3) the build-up of excessive amounts of adhesive between the threaded insert and the arrow shaft forcing the threaded insert face out of perpendicular alignment with the longitudinal axis of the arrow shaft. When any of these situations occur, the tip when threaded into or onto the threaded insert will abut the misaligned insert face forcing the tip out of collinear alignment with the longitudinal axis of the arrow shaft. 
   The adhesive used to join the threaded insert to the arrow shaft is normally an epoxy or a hot-melt glue. When applying the adhesive, an archer who is performing this operation will not have the necessary tools to ensure that the runout between the threaded insert and the arrow shaft is minimized when the threaded insert is assembled. A small error in runout (i.e., misalignment) on the mounting surface is greatly magnified at the arrow tip. The minimum magnification ratio of this error is normally about 10:1. An exemplary 0.025 mm (0.001 inch) error in runout will therefore magnify to a 0.25 mm (0.01 inch) misalignment of the arrow tip from the desired longitudinal axis of the arrow shaft. 
   A further drawback exists if the alignment of the machined or squared end of the arrow shaft is not perpendicular with the longitudinal axis of the arrow shaft. An archer when joining the threaded insert to the arrow shaft normally has no means of truing the end of the arrow shaft before insertion of the threaded insert. This error is further magnified when the threaded insert is joined with the arrow shaft. Most arrow shafts are now constructed of aluminum or a carbon fiber composite material. At the present time, there is a need for an effective means to machine, clean, or de-burr the end of an arrow shaft, and, when the shaft material is a carbon fiber composite, an effective means that minimizes splintering of the arrow shaft. 
   SUMMARY OF THE INVENTION 
   According to one aspect of the present invention, an apparatus is provided to perpendicularly align an end face on an arrow shaft with the arrow longitudinal axis. In this regard, the present invention may be utilized at the forward (tip) end of the arrow shaft with or without an arrow insert or the rear (nock) end of the arrow shaft. Furthermore, the present invention may be used in the first instance to assemble a new arrow during maintenance of an arrow or to re-square an arrow. The apparatus comprises a frame having at least one longitudinal channel. The channel is in parallel alignment with the frame&#39;s longitudinal axis. A cutting surface is mounted on the frame perpendicularly aligned to the frame longitudinal axis. An assembly which includes an insert and an arrow shaft is rotatably supported by the channel. The insert end of the assembly is placed adjacent to the cutting surface. The assembly is rotated within the channel and a face of the insert end is cut against the cutting surface to perpendicularly align a face of the insert end with the arrow longitudinal axis. 
   In a further aspect of the present invention, a hand tool for machining true an arrow insert is provided. This hand tool comprises a tool frame having a head portion and a base portion. The first channel is provided in the head portion. A second channel is provided in the base portion, wherein the second channel is collinearly aligned with the first channel. A cutting tool is supported from the head portion by a tool support channel. A cutting face of the cutting tool is perpendicularly aligned with both the channels. An arrow shaft which has an insert end is longitudinally aligned within both the channels and the insert end is rotated against the cutting face to perpendicularly true the insert end to the arrow shaft. 
   In a further aspect of the invention, a hand tool for machining true an arrow insert is provided. The hand tool comprises a tool frame having a head portion, a base portion, and a longitudinal axis. A V-shaped first channel is provided in the head portion. The first channel is parallel to the longitudinal axis. A V-shaped second channel is provided in the base portion. The second channel is also parallel to the longitudinal axis and collinearly aligned with the first channel. A cutting tool is supported from the head portion, the cutting tool adjacent to the first channel. A cutting face of the cutting tool is perpendicularly aligned with both the first and the second channels. An arrow shaft having an insert is longitudinally rotatably aligned along an arrow shaft longitudinal axis within both the first and the second channels. The insert is positioned adjacent to the cutting face, and the insert is perpendicularly trued by the cutting face to the arrow shaft longitudinal axis by rotating the arrow shaft within the first and second channels. 
   In still a further version of the invention, a method for truing an arrow insert is provided. The method comprises the steps of providing a tool frame having a head portion, a base portion, and a longitudinal axis; disposing a V-shaped first channel in the head portion, the first channel parallel to the longitudinal axis; disposing a V-shaped second channel in the base portion, the second channel parallel to the longitudinal axis; supporting a cutting tool from the head portion, the cutting tool adjacent to the first channel; perpendicularly aligning a cutting face of the cutting tool with both the first and second channel; rotatably aligning an arrow shaft within both the first and second channels; positioning the insert end of the arrow shaft and insert assembly adjacent to the cutting face; and rotating the arrow shaft within the first and second channels to remove material from a face of the insert and perpendicularly true the insert face to the arrow shaft longitudinal axis. 
   Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
       FIG. 1A  is a plan view of the tool frame of the present invention; 
       FIG. 1B  is a plan view of an alternate embodiment of the tool frame; 
       FIG. 2  is a sectioned side elevation view of the tool frame of the present invention taken through Section  2 — 2  of  FIG. 1 ; 
       FIG. 3A  is an end elevation view of the tool frame of the present invention shown in  FIG. 1A ; 
       FIG. 3B  is an end elevation view of the alternate embodiment of the tool frame shown in  FIG. 1B ; 
       FIG. 4  is a partial cross sectional view showing the cutting face of the cutting tool and the face of the insert perpendicularly aligned with the longitudinal axis of both the insert and arrow shaft; 
       FIG. 5  is a partial cross sectional view of the insert and arrow shaft following insertion of the insert into the body bore of the arrow shaft; 
       FIG. 6  is a perspective view of the tool frame of the present invention showing the installation of the cutting tool and the orientation of a typical arrow for truing the end of the arrow insert applying the present invention; 
       FIG. 7  is an elevation view showing the cutting tool of the present invention inserted in the support channel of the tool frame; and 
       FIG. 8  is a cross section view taken along section III—III of  FIG. 6  showing greater than 50% contact between the arrow insert face and the cutting tool face of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
   Referring to  FIGS. 1A and 3A , a tool frame  10  of the present invention is shown. Tool frame  10  comprises a head  12 , a body  14  and a base  16 . A first V-channel  18  is formed in the head  12 . A second V-channel  20  is formed in the base portion of the tool frame  10 . Both first V-channel  18  and second V-channel  20  are parallel to a longitudinal axis F of tool frame  10 . A tool clearance channel  22  is formed perpendicular to the alignment of first V-channel  18 . A tool support channel  24  is formed as an extended portion of the first V-channel  18 . 
   First V-channel  18 , second V-channel  20  and tool support channel  24  are shown in the arrangement of  FIGS. 1–3  as V-shaped channels. This configuration can be modified to suit the arrangement of the arrow design which will be supported by these channels. Other options for the arrangement of the channels include, but are not limited to, U-shaped, rounded or other concave geometric shapes, in place of first V-channel  18  and second V-channel  20  to provide means for longitudinally supporting and aligning an arrow shaft (shown in  FIG. 6 ). 
   Referring now to  FIGS. 1B and 3B , an alternate embodiment of a tool frame  10 ′ of the present invention is shown. Tool frame  10 ′ comprises a head  12 ′, a body  14 ′ and a base  16 ′. In this alternate embodiment, a dynamic locator is utilized in place of the first and second V-channels to provide means for longitudinally supporting and aligning an arrow shaft. Specifically, the dynamic locator includes a first roller mechanism  18 ′ formed in head  12 ′ and a second knife edge roller  20 ′ formed in the base portion  16 ′ of the tool frame  10 ′. In this regard, the knife edge rollers include a pair of disks which are supported on the tool frame  10 ′ so as to define a cradle for supporting the arrow shaft. Each of the disks are journally supported within the frame to allow for rotation therein. As such, the knife edge rollers function in a manner similar to the first and second V-channels  16 ,  18 . Other dynamic locators such as ball or roller bearing mechanisms may be utilized in a similar matter, and thus are contemplated by the present invention. 
   Referring now to  FIG. 2 , a side elevation view of the tool frame  10  is shown. Tool clearance channel  22  is shown having a tool stop end  26 . Flattened support faces comprising head support face  28  and base support face  30  are shown. Head support face  28  is formed at the head  12  end of tool frame  10 . Base support face  30  is formed at the base  14  end of tool frame  10 . Both head support face  28  and base support face  30  are co-planer and are formed such that the tool frame  10  may be supported by a flat surface to provide non-rotational support for tool frame  10 . In a preferred embodiment of the invention, both the head support face  28  and the base support face  30  are provided with a non-slip surface material minimizing the potential for movement of the tool frame when put to its intended use. Head support face  28  and base support face  30  are generally formed at about a 180° rotated position from the V-shaped channel locations of the tool frame  10 . This arrangement provides access to the V-shaped channels  18 ,  20  and the tool support channel  24  for use of the tool.  FIG. 2  also shows a length A of tool frame  10 . In a preferred embodiment of the invention, length A is about 15.2 cm (6 inches). 
   Referring now to  FIG. 3 , an end elevation view of tool frame  10  of the present invention is shown for the head  12  end. Head  12  comprises a diameter B. In a preferred embodiment of the invention diameter B is about 3.2 cm (1.25 inches). Tool support channel  24  comprising a V-shape is also shown. Head support face  28  is also shown in  FIG. 3 . 
   Referring now to  FIGS. 4 and 5 , a partial cross-sectional view of a normal assembly of an insert to an arrow body in relation to a cutting tool of the present invention is shown.  FIG. 4  shows a cutting tool  32 , comprising a tool body  34  and a cutting head  36 . A cutting face  38  of the cutting head  36  is provided such that cutting face  38  is perpendicular to a central longitudinal axis formed by the group including the cutting tool  32 , the insert  40  and the arrow shaft  46 . The insert  40  comprises an insert flange  42  and an insert body  44 . Insert body  44  is slidably disposed into an arrow shaft  46  within an inner bore  48  of the arrow shaft  46  in a conventional manner. Arrow shaft  46  also includes an end face  50  which abuts the insert flange  42  when the insert  40  is disposed within the arrow shaft  46 . 
     FIG. 5  shows the after-installed sub-assembly of insert  40  and the arrow shaft  46 . After assembly, the insert body  44  is slidably disposed within inner bore  48  of arrow shaft  46  as shown. The insert flange  42  abuts the end face  50  of the arrow shaft  46 . A plurality of retention grooves  52  are provided on insert body  44  to retain insert  40  within inner bore  48 . The gap between the retention grooves  52  and the inner bore  48  is normally filled with an adhesive (not shown) to form a positive seal between the insert body  44  and the inner bore  48 . The use of the adhesive often causes a misalignment, i.e., runout of the longitudinal axis of the insert  40  with respect to the longitudinal axis of the arrow shaft  46 . 
   Arrow shaft  46  normally comprises aluminum or carbon fiber composite materials. Most modern arrow shafts are provided in aluminum material. End face  50  of arrow shaft  46  is normally provided perpendicular to the longitudinal axis of arrow shaft  46  such that an insert face  54  of the insert  40  inserted into the arrow shaft  46  is perpendicular to the longitudinal axis of the arrow shaft  46 . 
   Referring now to  FIGS. 6 and 7 , the tool frame  10  having cutting tool  32  in its installed position is shown with an assembly comprising the insert  40  and arrow shaft  46  in preparation for truing the insert face  54  of the insert  40 . The cutting head  36  of cutting tool  32  is arranged such that the cutting head  36  abuts the tool stop  26 . The tool body  34  is supported within the tool support channel  24  of the tool frame  10  so that the cutting tool may be fixedly secured to the tool frame  10  with a fastener (not shown) or suitable adhesive. The tool clearance channel  22  is dimensioned such that the diameter of the cutting head  36  of the cutting tool  32  is provided with clearance to maintain parallel alignment between the cutting tool  32  and the longitudinal axis of the tool frame  10 . When supported by the tool frame  10 , the cutting face  38  of the cutting tool  32  is aligned perpendicular to the longitudinal axis of tool frame  10 . An arrow shaft  46  having the insert  40  previously installed is shown in position to cut the insert face  54  of insert  40  perpendicular to the longitudinal axis of both the arrow shaft  46  and the longitudinal axis F of tool frame  10 . Tool frame  10  is supported on any flat surface (not shown) by head support face  28  and base support face  30 . The arrow shaft  46  is rotatably supported within both first V-channel  18  and second V-channel  20  of the tool frame  10  such that the longitudinal axis of the arrow shaft  46  is parallel to the longitudinal axis F of tool frame  10 . 
   To cut or true the insert face  54  of the insert  40 , the arrow shaft  46  is rotated in direction of arrow C as shown and simultaneously translated in direction D. A combination of rotation and translation of the arrow shaft  46  presses the insert face against the cutting face  38  to cut or true the insert face  54 . It is necessary that a minimum of 50% of the surface area of insert face  54  contact the cutting face  38  of cutting tool  32 . This ensures that perpendicularity of the insert face is maintained when the insert face  54  is trued. 
   Referring now to  FIG. 7 , an end view of the tool frame  10  is shown.  FIG. 7  shows the head  12  and the head support face  28 . The cutting tool  32  is shown supported within the first V-channel  18  along the tool support channel  24 . A portion (in dashed lines) of the cutting head  36  of the cutting tool  32  abuts the tool stop  26  to retain the cutting tool  32  against the translation of the arrow shaft  46  in the direction D shown in  FIG. 6 . 
   Referring to  FIG. 8 , a section view is shown through the end of arrow shaft  46  looking toward the cutting face  38  of the cutting tool  32 . It is important to maintain a minimum of 50% engagement between insert face  54  of insert  40  and the cutting face  38  of cutting tool  32 . As shown in  FIG. 8 , this is accomplished by having the arrow longitudinal axis H positioned below the top of the cutting face  38 . A 360° rotation of arrow shaft  46  will therefore allow the entire surface of insert face  54  to contact cutting face  38 . 
   Referring back to  FIG. 2 , the vertices of first V-channel  18  and second V-channel  20  lie in the plane E defined by tool support channel  24 . It is critical that this relationship be maintained in order to retain the collinear alignment of these channels in parallel with the longitudinal axis F of the tool frame  10 . Dimension A, the length of tool frame  10 , and dimension G, the distance between first V-shaped channel  18  and second V-shaped channel  20 , are controlled such that an arrow shaft  46  supported between the V-shaped channels will not be separated by too great a distance allowing the arrow shaft to skew or bend between V-shaped channel support points. Dimension G is also controlled to maintain sufficient clearance between V-shaped channels to prevent an arrow shaft from ‘rocking-out’ of V-shaped channel  18  due to insufficient support length, and subsequent non-perpendicular cutting of the insert  40 . It is also necessary to size and position the V-shaped channels to maintain clearance between the diameter of the body  14  and the arrow shaft. This clearance ensures that an arrow shaft  46  supported by the tool frame  10  will not contact the body  14  as the arrow shaft  46  rotates. 
   Cutting tool  32  can be affixed to tool frame  10  in a permanent or semi-permanent installation. Means (not shown) of attaching cutting tool  32  to tool frame  10  can be by a strap (not shown) or other mechanical devices. It is necessary to retain the cutting tool  32  against the tool support channel  24  such that the cutting tool  32  is not allowed to rotate as the arrow shaft  46  rotates against the cutting face  38  of the cutting tool  32 . A semi-permanent means of affixing the cutting tool  32  is preferred as it permits replacement of the cutting tool  32 . The end face  50  of the arrow shaft  46  may also be trued, de-burred, or cleaned using the cutting tool  32  of the present invention. If the arrow shaft  46  material is aluminum, the invention can readily be used to true the end of the arrow shaft  46 . If the arrow shaft  46  is a carbon fiber composite material, however, the material of the arrow shaft may splinter against the cutting face  38  of cutting tool  32 . The truing of the face of an arrow shaft of carbon fiber composite material must therefore be performed with greater care. When truing, de-burring, or cleaning the end face  50  of an arrow shaft of carbon fiber composite material, the preferable material for the cutting face  38  of the cutting tool  32  would be an abrasive such as a diamond impregnated adhesive, aluminum oxide or carborundum in place of carbide. 
   In one version of the invention the V-shaped channels  18  and  20 , as well as the tool support channel  24  are anodized with a hard plastic coating impregnated in the face of each V-channel. Providing this anodized face reduces the friction when the arrow shaft rotates within the V-shaped channels. In another version of the invention, the V-shaped channels are not anodized with a plastic coating because the material of tool frame  10  comprises a metallic material such that the V-shaped channels are hardened to a Rockwell hardness in the range of about C60 to about C70 Rockwell hardness. This degree of hardness promotes minimum sliding friction between the V-shaped channel and the outside body of the arrow shaft. In yet another version of the invention, the use of dynamic locating devices (e.g. knife-edge rollers, ball or roller bearings, etc.), in place of V-channels, would promote minimum friction in the rotation of the arrow shaft. 
   Modern arrow shafts vary in diameter up to about 0.89 centimeters (0.35 inches). The use of V-shaped channels or an alternate to the V-shaped channel identified herein assures that the longitudinal axis of the arrow shaft is parallel to the longitudinal axis F of the tool frame  10  regardless of its diameter. 
   The preferable material for the cutting face  38  of the cutting tool  32  is a high strength steel or carbide material. Other materials can be substituted for the cutting face  38  including Carborundum, aluminum oxide, diamond impregnated, or similar abrasives in place of carbide. A smooth finish is desired for the insert face  54  after truing by the present invention. The material for tool frame  10  is preferentially aluminum. Plastic materials can also be used for tool frame  10  provided that the material chosen provides sufficient stiffness to maintain collinear alignment of the V-shaped channels (including the tool support channel). Collinear alignment of the V-shaped channels is critical to permit truing of the insert face  54  perpendicular to the longitudinal axis of the arrow shaft. 
   The geometry of the V-shaped channels can be varied from that shown by the figures provided herein without departing from the spirit and scope of the present invention. A V-shaped channel is preferred in order to accommodate a wide range of arrow shaft diameters with the present invention. While V-shaped channels  18 ,  20  and  24  as shown have an included angle of 90°, a greater or less than 90° separation between walls of the channels can be used without departing from the spirit or scope of the invention. Likewise, other geometric shapes or dynamic locating devices can also be provided as long as the requirement for a minimum of 50% engagement between insert face  54  of insert  40  and the cutting face  38  of cutting tool  32  is provided. 
   It is desirable to cut or true the insert face of the insert to within about 0.008 mm (0.003 inches) perpendicularity to the longitudinal axis of the arrow shaft. In use it is also desirable to identify when the insert face has been trued over its entire face. This can be accomplished by first marking the insert face, prior to engaging the insert face with the cutting tool, with a material such as a bluing agent, a chalk material, or an ink, i.e. from a permanent ink marker. Visual indication of complete cutting of the insert face will therefore be provided by removal of the marking material from the insert face by the cutting tool. 
   The present invention provides several advantages. A user in the field can improve the collinear alignment of an arrow tip to the longitudinal axis of the arrow shaft, thus improving arrow flight accuracy. The cutting tool is provided on a tool frame which is relatively small to be easily transported and used in the field. The cutting tool is replaceable and the overall tool frame can be supported on any flat surface. 
   The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.