Abstract:
An arrowhead assembly includes a blade tube that may rotate in flight at a rate during flight that is independent from the arrow shaft rotation. The assembly, upon and after impact with the target, continues rotational motion of the blade tube to penetrate a substantial distance into the target. Such characteristics are facilitated by the spiral-shaped, or twisting, nature of the blades as well as the rotational motion that is imparted by a spring arrangement of the assembly after compression and expansion of the spring arrangement upon impact.

Description:
FIELD 
       [0001]    The present invention relates generally to arrowhead assemblies for use in bow-and-arrow target shooting and hunting; and, more specifically, to an improved broadhead-type arrowhead assembly having improved flight and performance characteristics achieved through the use of curved blades and rotational motion occurring during flight and continuing after impact of the arrowhead assembly. 
       BACKGROUND 
       [0002]    A bow and arrow arrangement is a popular form of hunting game. The arrangement allows for improved accuracy and a quieter presence in the field as opposed to hunting with a rifle or a shotgun. An arrow typically comprises an arrowhead assembly with a pointed or tapered end and a shaft, an end of which shaft engages with a tension wire arrangement on the bow. A user may draw the shaft against the tension wire arrangement, and thereafter release the shaft, which propels the arrow away from the bow and the user after the tension wire arrangement returns to its rest position. 
         [0003]    Arrowhead assemblies (also referred to herein as “broadheads”) of arrows known in the art usually have straight blades that are in-line with regard to the shaft of the arrow. In this configuration, the arrow may rotate in flight after it is propelled away from the bow. However, the rotational motion will cease upon or shortly after impact on a target. Accordingly, upon striking a target, only the arrow&#39;s linear momentum will carry the arrow into the target. In such a case, the arrow may exit the mass of the target after entry. In the case where wild game is the target, the exiting of the arrow will decrease the probability that the game will be felled or killed by the arrow, and that the game will only be injured by the arrow. However, the game most likely will eventually bleed to death, which delay is an inhumane end to the game&#39;s life. 
         [0004]    Attempts have been made to improve the rotational motion of an arrow and arrowhead assembly after the user has released the arrow from the bow, however, these attempts do not solve the problem of the cessation of rotational motion after impact of the arrowhead assembly. 
         [0005]    Accordingly, there exists a need for an arrowhead assembly, and more specifically, an arrowhead assembly for use with a bow and arrow, that allows for still accuracy and consistency in flight before imparting rotational motion of the arrowhead assembly after the arrow&#39;s impact on a target. Further, the arrowhead assembly should be capable of manufacture in a lightweight, easy-to-use, and cost-effective manner. 
       SUMMARY 
       [0006]    Briefly described, in a preferred embodiment, the present invention overcomes the above-mentioned disadvantages and meets the recognized need for such a device by providing an improved arrowhead assembly design which includes curved blades of increasing width as measured from the leading edge thereof to the central axis of the arrowhead assembly. The curved blades of the arrowhead assembly provides the arrowhead assembly improved rotational motion that effectively promotes true flight, enhanced and more forceful target penetration, and stable and predictable flight path. 
         [0007]    Additionally, a spring arrangement, retained within the arrowhead assembly, is utilized to provide rotational motion of the arrowhead assembly upon impact with a target. The spring arrangement permits independent rotation of the arrowhead assembly relative to the arrow shaft, wherein the rotation of the arrowhead assembly is preferably substantially along the longitudinal axis of the shaft. 
         [0008]    The spring arrangement insert of the present invention preferably enables the broadhead-type arrowhead assembly to rotate at a rate during flight that is independent from the arrow shaft rotation; and, further, upon impact with the target, allows the arrowhead assembly to continue in its rotation to penetrate a substantial distance into the target. Such characteristics are facilitated by the spiral-shaped, or twisting, nature of the blades as well as the rotational motion that is imparted by the spring arrangement after compression and expansion of the spring arrangement upon impact. 
         [0009]    Accordingly, a feature and advantage of the present invention is its ability to overcome the deficiencies in prior art arrowhead assemblies by providing an improved arrowhead assembly in accordance with the disclosure herein. 
         [0010]    Another feature and advantage of the present invention is its ability to provide an improved arrowhead assembly having improved cutting and target penetration characteristics. 
         [0011]    Still another feature and advantage of the present invention is its ability to provide an improved arrowhead assembly having improved flight and accuracy characteristics. 
         [0012]    A further feature and advantage of the present invention is its ability to provide an improved arrowhead assembly having more humane effects on a game target. 
         [0013]    These and other features and advantages of the present invention will become more apparent to one skilled in the art from the following description and claims when read in light of the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The present invention will be better understood by reading the Detailed Description with reference to the accompanying drawing figures, in which like reference numerals denote similar structure and refer to like elements throughout, and in which: 
           [0015]      FIG. 1  is a view of a rotary arrowhead assembly in a disassembled state, according to a preferred embodiment of the present invention; 
           [0016]      FIG. 2  is perspective views of a first blade and a cylindrical body of a rotary arrowhead assembly, according to a preferred embodiment of the present invention; 
           [0017]      FIG. 3  is a view of a push spring of a rotary arrowhead assembly, according to a preferred embodiment of the present invention; 
           [0018]      FIG. 4  is a view of a torsion spring of a rotary arrowhead assembly, in accordance with a preferred embodiment of the present invention; 
           [0019]      FIG. 5  is a view of a firing pin of a rotary arrowhead assembly, in accordance with an exemplary embodiment of the present invention; 
           [0020]      FIG. 6  is an alternate perspective view of a tubular body of a rotary arrowhead assembly, in accordance with a preferred embodiment of the present invention; 
           [0021]      FIG. 7  is perspective views of a tubular body of a rotary arrowhead assembly, in accordance with a preferred embodiment of the present invention; 
           [0022]      FIG. 8  is perspective views of alternate embodiments of a blade tube for a rotary arrowhead assembly, in accordance with preferred embodiments of the present invention; 
           [0023]      FIG. 9  is a perspective view of a blade tube with firing pin holes and a torsion spring hole, in accordance with a preferred embodiment of the present invention; 
           [0024]      FIG. 10  is perspective views of blades and blade arrangements, in accordance with a preferred embodiment of the present invention; 
           [0025]      FIG. 11  is a perspective view of a coupling shaft of a rotary arrowhead assembly, in accordance with a preferred embodiment of the present invention; and 
           [0026]      FIG. 12  is a view of a first blade of a rotary arrowhead assembly, in accordance with a preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    In describing the preferred and selected alternate embodiments of the present invention, as illustrated in  FIGS. 1-12 , specific terminology is employed for the sake of clarity. The invention, however, is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish similar functions. 
         [0028]    Referring now to  FIG.2 , in an embodiment, an arrowhead assembly comprises a first blade  100 , which blade comprises a pointed tip that is disposed at a first end of the assembly. In use, the pointed tip is the first point of contact of the assembly with a target as the assembly impacts a target. The blade  100  further comprises a plurality of beveled regions  102   a,    102   b,    102   c,  and  102   d,  which regions enable the assembly to pass through the mass of a target, and in one embodiment, shatter the bone matter of a game animal.  FIG. 12  shows another perspective view of a blade  100 . 
         [0029]    The first blade  100  is removably attached to a cylindrical body  106 , which body comprises a first end and a second end. The first end comprises a slot capable of receiving and securing a portion of the blade  100 . In an embodiment, the blade  100  is secured by roll pins  101   a  and  101   b  that project from a first and second point on the circumference of the body  106  through apertures in the blade and into a third and fourth point on the circumference of the body  106 . 
         [0030]    The cylindrical body  106  further comprises a first elongated hollow region  103   a  and a second elongated hollow region  104   a,  each of which hollow regions are oriented substantially along the longitudinal axis of the cylinder and permit passage through the entire diameter of the cylindrical body  106 . The first hollow region  103   a  will be discussed in further detail in connection with  FIG. 7A . The second hollow region  104   a  will be discussed in further detail in connection with  FIG. 5 . The second hollow region  104   a  further comprises opposing apertures  105   a  and  105   b  that extend from the interior of the cylindrical body  106  to the exterior of the cylindrical body  106 . The apertures  105   a  and  105   b  are aligned in a substantially linear configuration such that a roll pin (not shown) may be inserted through the apertures, which roll pin passes through the second hollow region  104   a.    
         [0031]    The cylindrical body  106  further comprises a shaft  107  disposed on and extending away from the second end of the body  107 . In an embodiment, the shaft  107  is cylindrical and is concentric to and of a smaller circumference than the body  106 . The shaft  107  is adapted to receive a push spring  120  (shown in  FIG. 3 .), around the circumference of the shaft  107 . 
         [0032]    Referring to  FIGS. 4A and 4B , the assembly further comprises a torsion spring  130 , which spring will be described in further detail below. 
         [0033]    Referring to  FIG. 5 , a firing pin  140  of an arrowhead assembly is shown. The firing pin comprises a flat ring portion and a cylindrical flange attached to and extending away from the ring portion. The firing pin  140  will be described in further detail below. 
         [0034]    Referring now to  FIGS. 6 ,  7 A, and  7 B, alternate views of a tubular body  170  of an arrowhead assembly are shown. The tubular body  170  comprises a first end, a second end, and a hollow interior portion. The first end of the tubular body includes a flange region  150  that extends along a portion of the tubular body  170  and extends away from the circumference of the tubular body  170 . The flange region includes a pair of apertures  103   b  and  103   c  that are disposed linearly on opposite points of the circumference of the flange region and that are configured to accommodate a roll pin.  FIG. 6  shows a perspective view of the first end of the tubular body  170 , including the interior region  180 , the exterior region  185 , and the apertures  103   b  and  103   c.  The flange region further comprises two substantially planar regions  108   a  and  108   b  that are adjacent to the apertures and are capable of accommodating a wrench for aiding in the installation and manipulation of the assembly. 
         [0035]    The tubular body  170  further comprises an elongate slot  109  disposed on a section of the body. The slot is parallel to the axis of the tubular body and is of a length that is approximately one fifth of the length of the body. The slot  109  is configured to accommodate the cylindrical flange of the firing pin  140  and the slot includes a shelf  160  disposed at the end of the slot that is proximate to the first end of the body. The shelf sits below the exterior surface of the tubular body and is capable of accommodating the distal end of the cylindrical flange of the firing pin  140  such that the shelf may prevent the firing pin from rotating such that the firing pin of the flange does not enter the interior of the tubular body. The interior of the second end of the tubular body  170  comprises a female threaded portion  111 , the threads of which threaded portion are of a left-handed orientation, and which threads will be described in further detail below. 
         [0036]    The tubular body  170  further comprises an access aperture  112  that is substantially opposite to the elongate slot  109 . The access aperture  112  is capable of accepting an instrument (not shown) to aid in the manipulation of the assembly in a pre-firing position (to be described in detail below). 
         [0037]    Referring to  FIGS. 8A ,  8 B, and  8 C, alternate embodiments of a blade tube  190  of an arrowhead assembly are shown. At least two blades  200  are disposed on and extend away from the blade tube  190 , which blades may be substantially planar or may be curved.  FIGS. 10A and 10B  show perspective views of a blade of the blades  200  that extend outwardly away from blade tube  190 . In an embodiment, a blade of the blades  200  comprises a cut-out portion that assists in reducing weight of the assembly. In another embodiment, the edge of a blade of the blades  200  that is distal to the tip of the assembly comprises a semi-cylindrical configuration, such that said distal edge may cause the blades to undergo a tunneling or spiral motion while passing through a target mass, which motion may reduce the resistance of the assembly&#39;s passage through the target and may increase the amount of mass of the target that is addressed by the assembly. In another embodiment, the edge of a blade of the blades that is distal to the tip of the assembly comprises a beveled region beginning at the side of the edge that is proximate to the interior of the cut-out portion and extending to the edge that is distal to the cut-out portion, which beveled region is disposed at an angle such that the region extends away from the semi-cylindrical edge of the blade. In an embodiment, the beveled region is at a 20 degree angle with respect to the flat edges of a blade. 
         [0038]    Referring now to  FIG. 9 , another view of blade tube  190  of an arrowhead assembly is shown. The blade tube comprises at least two blades  200  that extend outwardly away from the blade tube  190 . The blade tube  190  further comprises a hollow inner portion which is capable of accommodating a torsion spring and a shaft (which shaft will be described further in connection with  FIG. 11 ). The blade tube  190  further comprises a first torsion spring aperture  113 , which is capable of accommodating an end of a torsion spring. The blade tube  190  also comprises a plurality of firing pin apertures  114 , such as the apertures  114   a,    114   b,    114   c,  and  114   d,  which apertures  114   a  and  114   b  are disposed at substantially identical positions with regard to the distance from the tip of the assembly, and are spaced equidistant from each other along the circumference of the blade tube. In an embodiment, the blade tube comprises four firing pin apertures. With respect to the firing pin apertures  114 , the first torsion spring aperture  113  is situated near the end of the blade tube that is distal to the tip of the assembly, and the firing pin apertures  114  are disposed near the end of the blade tube that is proximate to the tip of the assembly. 
         [0039]    Referring now to  FIG. 11 , a substantially cylindrical coupling shaft  210  of an arrowhead assembly is shown. The shaft  210  comprises a first end and a second end. The first end comprises a male threaded region  116 , which male threaded region comprises left handed threads for coupling with the female threads  111  of the tubular body  170 . At the end of the threaded region  116  that is distal to the first end of the shaft a thread stop  117  extends outwardly from the shaft, which stop  117  limits the extent of coupling of the shaft and tubular body. Disposed between the thread stop  117  and a first stop flange  119  is a mandrel  118  which is capable of insertion through the interior of and retaining a torsion spring. Disposed at approximately the midpoint of the shaft is a stop flange  119 , which flange extends outwardly away from the circumference of the shaft. The flange  119  is substantially cylindrical and may comprise oppositely disposed planar regions  108   c  and  108   d  about its circumference, which planar regions  108   c  and  108   d  are capable of accommodating a wrench for aiding in the installation and manipulation of the assembly. A second torsion spring aperture  115  is disposed on the side of the flange  119  that abuts the mandrel  118 , which aperture  115  extends inwardly into the flange  119  and which aperture is capable of accepting an end of a torsion spring. 
         [0040]    The second end of the shaft comprises a male threaded portion  121 , the threads of which are capable of mating with female threads of an arrow shaft known in the art to permit the assembly to securely attach to the arrow shaft to allow the assembly to be fired from a bow. 
         [0041]    In use, the components of the assembly are put together to provide an arrowhead assembly with improved characteristics, including, but not limited to, the capability to rotate in flight and after impact. 
         [0042]    To assemble an embodiment of assembly, the first blade  100  is inserted into the slot of the cylindrical body  106 , and the blade  100  is thereafter secured to the cylindrical body by roll pins  101   a  and  101   b.  A push spring is placed onto the shaft  107  of the cylindrical body  106 . A firing pin  140  is thereafter placed in the second hollow region  104   a  of the cylindrical body  106  such that the flat ring portion of the firing pin  140  is received in the second hollow region  104   a  of the cylindrical body. A roll pin may be inserted through aperture  105   a  of the cylindrical body  106 , on through the ring portion of the firing pin  140 , and on through aperture  105   b  of the cylindrical body to secure the firing pin  140  within the cylindrical body  106 . 
         [0043]    The tubular body  170  is thereafter slid over the cylindrical body  106  such that the apertures  103   b  and  103   c  of the tubular body  170  are aligned with the first elongated hollow region  103   a  of the cylindrical body  106 , and the elongate slot  109  of the tubular body  170  is aligned with the second hollow region  104   a  of the cylindrical body  106 . When the tubular body  170  and cylindrical body  106  are so situated, a user thereafter may insert a roll pin (not shown) into the aperture  103   b  of the tubular body, such that the roll pin extends from the aperture  103   b  through the hollow region  103   a  of the cylindrical body and on into the aperture  103   c  of the tubular body. In such an embodiment, the roll pin secures the cylindrical body within the tubular body. 
         [0044]    When the cylindrical body  106  is so secured within the tubular body  170 , the cylindrical flange of the firing pin  140  will extend out of the second hollow region  104   a  of the cylindrical body  106 , past the shelf  160  of the elongate slot of the tubular body  170  and out of the elongate slot  109  of the tubular body  170 , such that at least a portion of the cylindrical flange of the firing pin  140  protrudes out of the tubular body  170 . In an embodiment, a user may position an awl, a pin, or any other similar tool through the access aperture  112  to manipulate the firing pin into the preferred orientation. In this configuration of the cylindrical body and tubular body, the firing pin may pivot such that the cylindrical flange of the pin may be positioned against the shelf of the elongate slot of the tubular body or may be positioned substantially perpendicular to the axis of the cylindrical and tubular bodies, or any point in between. 
         [0045]    A torsion spring  130  is thereafter inserted into the hollow inner portion of the blade tube  190  such that the hooked end of the torsion spring is received in by the torsion spring aperture  113  of the blade tube  190 . In this embodiment, the hooked end of the torsion spring  130  extends through the aperture  113  and outwardly away from the blade tube  190 , with a substantial portion of the remaining length of the torsion spring being contained within the blade tube  190 . In this embodiment, after attachment of the torsion spring  130 , the blade tube  190  is slid over the tubular body  170  such that the tubular body is accepted within a portion of the hollow inner portion of the blade tube  190  and such that the firing pin apertures  114  of the blade tube  190  are proximate to the blade end of the assembly. 
         [0046]    In this embodiment, the coupling shaft  210  is thereafter slid into the blade tube such that the shaft  210  and mandrel  118  pass through the interior of the torsion spring until the substantially straight end of the torsion spring is received in the second torsion spring aperture  115  of the stop flange of the coupling shaft  210 . 
         [0047]    Within the blade tube  190 , the threaded end of coupling shaft  210  is thereafter disposed against the corresponding threaded end of the tubular body  170 , and the threaded portions thereof are mated for attachment of the coupling shaft  210  to the tubular body  170 . In this attached configuration of the coupling shaft and the tubular body, the torsion spring and mandrel are received within the hollow portion of the blade tube  190  such that blade tube  190  covers the full length of the torsion spring. In this embodiment, the firing pin apertures  114  of the blade tube  190  may be substantially aligned with the cylindrical flange of the firing pin  140 , when the flange extends upwardly out of the cylindrical body  106  and tubular body  170 . 
         [0048]    Further in this embodiment, the diameter of the tubular assembly corresponds to the diameter of inner hollow portion of the blade tube to allow the blade tube to rotate freely about the tubular body and to prevent the blade tube from moving in any other vector with respect to the stop flange. 
         [0049]    With the hooked end of the torsion spring inserted in to the first torsion spring aperture  113  of the blade tube, the blade tube is operatively coupled with the torsion spring. In this embodiment, the blade tube may be rotated such that the torsion spring is compressed and mechanical energy is stored therein. After the blade tube  190  is so rotated to the user&#39;s preference, the firing pin may be inserted through a firing pin aperture  114  of the blade tube to secure the blade tube in place around the tubular body  170 . 
         [0050]    In this embodiment, the end of the blade tube  190  that is proximate to the tip end of the assembly sits flush against the flange region  150  of the tubular body  170 , and the end of the blade tube that is distal to the tip end of the assembly sits flush against the first stop flange  119  of the coupling shaft  210 . In an embodiment, a second stop flange  129  that is concentric the first stop flange of the coupling shaft extends away from the distal end of the coupling shaft  210  and into the blade tube  190 , the diameter of which second stop flange corresponds to the diameter of inner hollow portion of the blade tube to allow the blade tube to rotate freely about the second stop flange and to prevent the blade tube from moving in any other vector with respect to the stop flange. 
         [0051]    Before use, the male threaded portion  121  of the coupling shaft are mated with corresponding female threads of an arrow shaft (not shown) to permit the assembly to securely attach to the arrow shaft and to allow the assembly to be fired from a bow. 
         [0052]    In use after assembly, the assembly may be fired from a bow. In flight, the assembly may rotate to improve aerodynamics and accuracy. Upon impact, the force of the impact causes the firing pin to move from its outwardly-projecting position to a position where its flange is disposed on the shelf of the elongate slot  109  of the tubular member  170 . In this position, the firing pin ceases its restriction of the rotation of the blade tube  190 , and the torsion spring thereafter imparts rotational motion upon the blade tube such that the blade tube rotates around the tubular member and about the longitudinal axis of the assembly. The rotational motion of the blade tube, combined with the configuration of the blades disposed on the blade tube, causes a boring effect inside the target after impact of the assembly upon the target. The boring effect improves the ease of passage of the assembly through the target as compared to existing arrowheads and arrow shafts, and, as further compared to existing arrowheads and arrow shafts, may cause a larger diameter and volume of the target&#39;s mass to be disrupted or removed upon passage of the assembly through the target. As a result, the assembly provides for a higher probability that a game target will be killed due to impact and passage therethrough of the assembly. This is as contrasted to the case of known arrowheads and arrow shafts, which may leave a small diameter of interruption after passing through a target, the result of which may not immediately kill a game target and may instead result in the target slowly bleeding to death. 
         [0053]    The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions, substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but is intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.