Patent Publication Number: US-11022413-B1

Title: Arrow insert with reinforcing collar

Description:
RELATED APPLICATIONS 
     This application claims the benefit of priority of U.S. Provisional Patent Application No. 62/801,035, filed on Feb. 4, 2019 by the same inventor, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates generally to archery, and more particularly to arrow insert/outsert assemblies. 
     Description of the Background Art 
     The demand for small-diameter arrow shafts is increasing in the archery industry. One advantage to small-diameter arrow shafts is that they have less exterior surface area. As a result, they experience less air drag and are, therefore, less affected by crosswinds during flight. Not only does mitigating air drag during flight result in more accurate shot placement, it also preserves more of the initial kinetic energy during flight. As a result, small-diameter arrows achieve higher velocities upon impacting the target. The reduced outer diameter also allows the arrow shaft to have a thicker and, therefore, stronger sidewall. 
     Although there are several advantages to small-diameter arrow shafts, there are also drawbacks. For example, the inside diameter of a small-diameter arrow shaft is not large enough to accept a standard arrow insert. As a result, special insert/outsert assemblies have to be used to fix arrowheads (e.g., target heads, broadheads, etc.) to small-diameter arrow shafts. 
     One prior art insert/outsert assembly, U.S. Pat. No. 9,638,499 (Perry), discloses an insert/outsert assembly including an insert coupled to an outsert. The insert includes a first end adapted to be adhered to the interior wall of an arrow shaft and a second end adapted to thread into the outsert. The outsert includes a first threaded end and a second threaded end. The first threaded end of the outsert is adapted to thread onto the second end of the insert. The second threaded end of the outsert includes a threaded bore (female threads) configured to receive complimentary male threads of an arrowhead. 
     For proper arrow flight, it is important that the arrowhead is coaxially aligned with the shaft of the arrow within some predetermined acceptable tolerance. Of course, such tolerances are dictated by a number of design, material, and manufacturing limitations. For example, in the insert/outsert assembly of Perry, the alignment of the arrowhead with respect the arrow shaft is dictated by a tolerance stack-up. This tolerance stack-up includes the alignment tolerance between the insert and the interior of the arrow shaft, the alignment tolerance between the outsert and the insert, and the alignment tolerance between the arrowhead and the outsert. Indeed, the tolerances become increasingly more strict and hard to achieve as the number of tolerances in the stack-up increases. 
     SUMMARY 
     What is needed is an insert/outsert assembly with more relaxed tolerances in the stack-up between the arrowhead and the arrow shaft. What is also needed is an insert outsert assembly that facilitates easy exchange of parts in a field situation. What is also needed is an insert/outsert assembly that is more robust than prior art assemblies. What is also needed is an insert/outsert assembly that remains assembled when the arrowhead is removed from the assembly. 
     Example assemblies for fixing an arrow tip to an arrow shaft are disclosed. An example assembly includes an insert and a sleeve. The insert has a first end and a second end. The first end of the insert is configured to be inserted into an end of the arrow shaft, and the second end of the insert is configured to receive a securing/anchoring end of the arrow tip. The sleeve is configured to surround at least a portion of the end of the arrow shaft and at least a portion of the insert. The insert includes an engagement mechanism, and the sleeve includes a complementary engagement mechanism. The engagement mechanism and the complementary engagement mechanism are configured to selectively engage one another. 
     In a particular non-limiting example, the second end of the insert defines a hollow cylindrical shell that has an internal surface and an external surface. The internal surface is configured to receive the end of the arrow tip (e.g., threaded, twist lock, etc.), and the external surface includes the engagement mechanism. The sleeve includes a cylindrical body having a first end, a second end, and an exterior surface. The cylindrical body defines an axial bore that passes through the first end and the second end of the cylindrical body. The axial bore is configured to fit around at least a portion of the end of the arrow shaft at the first end of the cylindrical body and to fit around the second end of the insert at the second end of the cylindrical body. The axial bore additionally defines the complementary engagement mechanism. 
     In an even more particular example, the engagement mechanism includes a first thread set, the complementary engagement mechanism includes a second thread set, which is configured to engage the first thread set. The axial alignment of the arrow tip and the arrow shaft is independent of a tolerance of engagement of the sleeve with the insert. In addition, the sleeve remains securely engaged with the insert, even without the arrow tip being coupled to the second end of the insert. Optionally, the insert is monolithic, and the sleeve is monolithic. 
     Some example embodiments optionally include a shoulder feature. For example, the axial bore can define a shoulder on an inner surface of the sleeve. When the sleeve is rotated about the insert, the engagement of the first thread set and the second thread set moves the shoulder toward the end of the arrow shaft or away from the end of the arrow shaft, depending on the direction of rotation of the sleeve with respect to the insert. Whereby, the shoulder can be urged against the end of the arrow shaft. 
     Some example embodiments also include a lip feature. The second end of the sleeve can include a circumferential lip extending into the bore. When the sleeve is rotated about the insert, the engagement of the first thread set and the second thread set moves the lip toward the second end of the insert or away from the second end of the insert, depending on the direction of rotation of the sleeve with respect to the insert. Whereby, the lip can be urged against the second end of the insert. 
     Multiple sleeves of different weights can be provided. For example, an example assembly can include a second sleeve. The original sleeve has a first weight, and the second sleeve has a second weight different than the first weight. The second sleeve is interchangeable with the first sleeve. In addition, the assembly can further include a third sleeve. The third sleeve has a third weight different than the first weight and the second weight. The third sleeve is also interchangeable with the original sleeve and the second sleeve. 
     In the example embodiments, the axial alignment of the arrow tip and the arrow shaft is independent of a tolerance of engagement of the sleeve with the insert. In addition, the sleeve remains securely engaged with the insert without the arrow tip being coupled to the second end of the insert. Optionally, the insert and/or the sleeve can be monolithic, and/or the sleeve can be directly connected to the insert. 
     Means for selectively, mechanically engaging a sleeve with an insert are disclosed. An example assembly for fixing an arrow tip to an arrow shaft includes an insert and a sleeve. The insert has a first end and a second end. The first end of the insert is configured to be inserted into (or otherwise fixed to) an end of the arrow shaft, and the second end of the insert is configured to receive an end (e.g., a threaded end) of the arrow tip. The sleeve is configured to surround at least a portion of the end of the arrow shaft and at least a portion of the insert. Means for selectively, mechanically engaging the sleeve with the insert are provided between the insert and the sleeve. 
     Example methods of manufacturing an assembly for fixing an arrow tip to an arrow shaft are also disclosed. One example method includes providing an insert having a first end and a second end, configuring the first end of the insert to be inserted into an end of the arrow shaft, and configuring the second end of the insert to receive an end of the arrow tip. The example method additionally includes forming an engagement mechanism on an outer surface of the insert. The method also includes providing a sleeve configured to surround at least a portion of the end of the arrow shaft and at least a portion of the insert, and forming a complementary engagement mechanism on an inner surface of the sleeve. The complementary engagement mechanism is configured to selectively engage the engagement mechanism of the insert. Optionally, the engagement mechanism can include a first thread set, and the complementary engagement mechanism includes a second thread set configured to engage the first thread set. As another option, the insert and/or the sleeve can be monolithic. 
     Another example method further includes providing an additional plurality of sleeves. Each additional sleeve is interchangeable with the original sleeve and has a weight different from a respective weight of each of the other sleeves of the additional plurality of sleeves and from a weight of the original sleeve. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described with reference to the following drawings, wherein like reference numbers denote substantially similar elements: 
         FIG. 1  is a side view of an example arrow assembly; 
         FIG. 2  is a side view of an insert/outsert assembly of the arrow of  FIG. 1 ; 
         FIG. 3  is an exploded side view of the insert/outsert assembly of  FIG. 1 ; 
         FIG. 4  is a cross-sectional side view of the insert/outsert assembly of  FIG. 1 ; 
         FIG. 5  shows specific dimensions of the insert of  FIG. 3 ; 
         FIG. 6  shows specific dimensions of the outsert of  FIG. 3 ; 
         FIG. 7  shows specific dimensions of an alternate outsert; 
         FIG. 8  shows specific dimensions of another alternate outsert; and 
         FIG. 9  is a flowchart summarizing a method of manufacturing an insert/outsert assembly. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention overcomes the problems associated with the prior art, by providing an insert/outsert assembly having a reduced number of tolerances in the tolerance stack-up between an arrowhead and an arrow shaft. In the following description, numerous specific details are set forth (e.g., materials, weight, etc.) in order to provide a thorough understanding of the invention. Those skilled in the art will recognize, however, that the invention may be practiced apart from these specific details. In other instances, details of well-known machining practices (e.g., turning, thread cutting, adhesives, etc.) and components have been omitted, so as not to unnecessarily obscure the present invention. 
       FIG. 1  shows a side view of an insert/outsert assembly  100  mounted to the end of an arrow  102 . Insert/outsert assembly  100  is fixed to the front end of arrow  102  to facilitate the removable coupling of an arrowhead  104  to arrow  102 . Insert/outsert assembly  100  also facilitates the removal of arrow  102  from a target (e.g., the tapered contour of the assembly reduces the rear-facing edge). In this example, arrow  102  further includes a small-diameter shaft  106 , a set of fletchings  108 , and a nock  110 . 
       FIG. 2  is close-up view of insert/outsert assembly  100  mounted to the front end of shaft  106 . In the example embodiment, arrowhead  104  is a target head. However, those skilled in the art will recognize that arrowhead  104  can be unscrewed from insert/outsert assembly  100  and replaced with any screw-in type arrowhead. As shown, the outer diameter of insert/outsert assembly  100  is greater than the outer diameter of shaft  106 , but gradually reduces and is smaller at the rear end of assembly  100 . 
       FIG. 3  is a side view of insert/outsert assembly  100  exploded from shaft  106 . In this example embodiment, insert/outsert assembly  100  includes a monolithic metal insert  300  and a monolithic metal outsert  302 . In this example embodiment, insert  300  can be formed from 416 stainless steel or 7075 aluminum with a hardened finish, and outsert  302  is machined out of billet of 7075 aluminum. However, any other suitable material(s) can be used to manufacture insert  300  and/or outsert  302 . 
     Insert  300  facilitates the mounting of arrowhead  104  to shaft  106  and includes a first end  304  and a second end  306 . First end  304  is configured to be inserted into the open end and adhered to the interior of the front end of shaft  106  by, for example, friction fit and/or epoxy or the like. First end  304  defines a plurality of barb features  308  formed thereon to prevent insert  300  from being pulled out of shaft  106  when arrow  102  is pulled from a target. Second end  306  is configured to receive arrowhead  104  and is configured to receive outsert  302 . More specifically, second end  306  includes a hollow, cylindrical shell that defines an interior threaded bore  310  (shown in  FIG. 4 ) and a smooth bore  311  ( FIG. 4 ), which are configured to receive a complimentary thread set  312  and a smooth shank  313  of arrowhead  104 , respectivley. Furthermore, second end  306  includes an external thread set  314  on an exterior surface of insert  300 , which is configured to thread into a complimentary thread set  316  (shown in  FIG. 4 ) formed on an interior bore  318  (also shown in  FIG. 4 ) passing through outsert  302 . 
     Outsert  302  is essentially a collar or sleeve that facilitates the removal of arrow  102  from a target and also provides structural reinforcement between insert/outsert assembly  100  and shaft  106 . In addition to thread set  316  of interior bore  318 , outsert  302  also includes a cylindrical exterior surface having a front region  320  and a rear region  322 . In the example embodiment, the outer diameter of front region  320  is substantially identical to the outer diameter of arrowhead  104 . This prevents damage to the target when arrow  102  impacts the target and/or is removed from the target. The outer diameter of rear region  322  is tapered down to provide a smooth surface transition between front region  320  and the exterior surface of shaft  106 . As previously mentioned, the tapered aspect of rear region  322  facilitates the extraction of arrow  102  from a target without destroying the target and/or pulling insert  300  from shaft  106 . 
     In addition to providing additional rigidity between shaft  106  and insert  300 , outsert  302  remains engaged with insert  300 , even when arrowhead  104  is removed from insert  300 . The engagement of threads  314  and  316  allow a lip at the front end  402  ( FIG. 4 ) to be urged against insert  300  when outsert  302  is rotated with respect to insert  300 . When the lip urges against insert  300 , the frictional force between threads  314  and  316  is increased, thereby preventing unintended rotation and/or loosening of outsert  302  with respect to insert  300 . This provides a substantial advantage, because it reduces the risk and inconvenience of outsert  302  falling off when changing arrowhead  104 . This advantage is even more valuable in field situations, where it is much more likely that a dropped insert would become lost. 
       FIG. 4  shows a cross-sectional view of insert/outsert assembly  100  and shaft  106  taken along line A-A of  FIG. 2 . The inner surface of outsert  302  defines a shoulder  324  that can be urged against the end of arrow shaft  106 , to provide some compression of outsert  302  and additional rigidity to assembly  100 . Rotating outsert  302  with respect to insert  300  with threads  314  and  316  engaged will cause shoulder  324  to move toward or away from the end of shaft  106 , depending on the direction of rotation. After bringing shoulder  324  into contact with the end of arrow shaft  106 , additional rotation of outsert  302  will selectively increase the force between shoulder  324  and shaft  106 . 
     In addition, the threaded engagement of insert  300  and outsert  302  can also facilitate the tuning of the orientation of an alternative arrowhead (e.g., a mulit-blade broadhead) with the orientation of fletchings  108 . For example, after a broadhead arrow is fully screwed into insert  300 , the blades of the broadhead might not be oriented properly with fletchings  108 . In that case, the broadhead can be backed out slightly to achieve the proper orientation of the broadhead blades, then outsert  302  can be backed off slightly to take up any slack in the threaded connection between the broadhead and insert  300 . 
     As illustrated by the previous examples, the adjustability of the position of outsert  302  along axis  326  provides multiple advantages. The coupling of outsert  302  to insert  300  via threads  314  and  316  provides the desired adjustability. 
     The structure of insert  300  also provides significant advantages. In particular, second end  306  of insert  300  includes threaded bore  310  and smooth bore  311  formed in the same unitary insert  300 . As explained above, threaded bore  310  receives thread set  312  of arrowhead  104 . In addition, smooth bore  311  has a larger diameter than threaded bore  310 , to closely receive almost the entirety of shank  313  of arrowhead  104 . Receiving both the threaded end and the larger shank  313  within unitary insert  300  substantially increases the strength of the attachment of arrowhead  104  to arrow shaft  106 . Indeed, the strength of the connection is increased sufficiently that arrow  100  could be safely fired into a target without outsert  302 . In contrast, in prior art devices, where an insert receives only the threaded end of an arrow head, impact with a target would cause the point end of the arrowhead to snap off of the threaded end. 
     The assembly of insert/outsert assembly  100 , arrowhead  104 , and shaft  106  will now be summarized. First, adhesive (e.g. an epoxy) is applied to first end  304  of insert  300 . First end  304  is then inserted into interior space  400  of shaft  106  and pressed in until second end  306  engages the planar front end of shaft  106 . Once the adhesive cures, outsert  302  is screwed onto insert  300  such that thread sets  314  and  316  engage one another. At this point, the interior of rear region  322  of outsert  302  fits against the outer surface of shaft  106  to provide additional structural support between insert/outsert assembly  100  and shaft  106 . Finally, arrowhead  104  is screwed into insert  300  through the front opening of outsert  302  until the front end  402  of outsert  302  frictionally engages the rear planar surface  404  of arrowhead  104 . 
     As previously mentioned, the coaxial mounting of the arrowhead with respect to the shaft is essential for optimal arrow flight. Of course, in reality this can only be done within a realistic overall tolerance that is dictated by the tolerance stack-up between the arrow shaft and the arrowhead. In the prior art, the tolerance stack-up includes three tolerances: the alignment tolerance between the insert and the interior of the arrow shaft; the alignment tolerance between the outsert and the insert; and the alignment tolerance between the arrowhead and the outsert. In the present invention however, the tolerance stack-up includes only two tolerances: the alignment tolerance between first end  304  of insert  300  and the interior of shaft  106 ; and the alignment tolerance between arrowhead  104  and insert  300 . By eliminating one alignment tolerance (outsert with respect to insert) from the stack-up, the present invention is able to achieve a much higher degree of accuracy in terms of coaxial alignment between arrowhead  104  and shaft  106 . In addition to achieving improved alignment, the relaxed tolerances also provide for simpler manufacturing of insert/outsert assembly  100  as compared to the prior art. Unlike the prior art, the alignment of arrowhead  104  with respect to insert  300  does not depend on the alignment of the outsert with respect to the insert. 
       FIG. 5  shows a blueprint of insert  300  according to one embodiment of the present invention. 
       FIG. 6  shows specific dimensions of outsert  302  according to a non-limiting example embodiment of the present invention. 
       FIG. 7  shows specific dimensions of another example outsert  700 . Outsert  700  is similar to outsert  302 , except that outsert  700  is made slightly heavier (e.g., by adjusting the contour and/or dimensions of outsert  700  to include more of the same material, by using different material, etc.) than outsert  302 , to accommodate for archer preference and/or achieve improved flight stability. Thus, the weight of insert/outsert assembly  100  can be increased simply by replacing outsert  302  with outsert  700 , without ever having to remove insert  300  from shaft  106 . 
       FIG. 8  shows specific dimensions of another example outsert  800 . Outsert  800  is similar to outserts  302  and  700 , except that outsert  800  is made slightly heavier than outsert  700 . So, the weight of insert/outsert assembly  100  can be further increased simply by replacing outsert  700  with outsert  800 , without ever having to remove insert  300  from shaft  106 . 
     In general, any number of differently weighted outserts, each configured to removably couple to insert  300 , can be provided in combination with insert  300 , to facilitate the selective adjustment of the weight of insert/outsert assembly  100 . The mechanical coupling (e.g., a thread set) facilitates the selective removal/replacement of the outserts, which provides an important advantage over prior art collars which may be permanently adhered (e.g., glued, pressed, etc.) to the insert. 
       FIG. 9  is a flowchart  900  summarizing a method of manufacturing an insert/outsert assembly. In a first step  902 , a monolithic insert is provided. Then, in a second step  904 , a first end of the insert is configured to be inserted into an arrow shaft. Next, in a third step  906 , a second end of the insert is configured to directly receive an arrowhead. Then, in a fourth step  908 , an outsert is provided. Finally, in a fifth step  910 , the insert and the outsert are configured to engage one another. 
     The description of particular embodiments of the present invention is now complete. Many of the described features may be substituted, altered or omitted without departing from the scope of the invention. For example, alternate arrow engaging features (e.g., knurling, ridges, channels, etc.), may be substituted for the barbs of the insert. As another example, alternate metals (or other materials) and dimensions may be used to achieve different weight and strength characteristics for the insert/outsert assembly. As yet another example, alternate engagement and/or complementary engagement mechanisms (e.g., twist-lock, cam-lock, etc.) can be substituted for the complementary thread set disclosed. These and other deviations from the particular embodiments shown will be apparent to those skilled in the art, particularly in view of the foregoing disclosure.