Patent Publication Number: US-8974328-B1

Title: Tunable broadhead with lockable blade assembly from shaft extending from broadhead tip

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application No. 61/731,249, filed Nov. 29, 2012, the entirety of which is incorporated herein. 
    
    
     FIELD OF THE INVENTION 
     This invention is directed generally to broadheads attachable to archery arrows used for hunting, and more particularly to tunable broadheads having features enabling the broadheads to be tuned relative to the arrows to which the broadheads are attached to enhance the flight characteristics of the broadheads. 
     BACKGROUND 
     Modern broadheads are tips attachable to a distal end of an arrow shaft and include one or more blades having cutting arrises. The blades extend outwardly from a generally cylindrical broadhead body. The blades typically extend from the broadhead such that the cutting arris of each blade are at an acute angle relative to a longitudinal axis of the broadhead body and extend from a distal point at an intersection at an outer surface of the broadhead body to near the tip at an outer surface of the broadhead body to a proximal point radially outward of the outer surface of the broadhead body. In this position, the blades are capable of cutting flesh as the broadhead passes through an animal. 
     Modern compound bows can propel arrows at speeds of greater than 300 feet per second. Accurate arrow flight at such speeds is typically only accomplished when all components of the bow and arrow system are tuned properly. For instance, cam timing, cam and wheel alignment, rest position, arrow nock position, fletching clearance, arrow weight consistency, arrow spline consistency, broadhead configuration, and broadhead alignment are all factors that can each greatly affect accuracy. Broadheads have always proved challenging to tune. A longitudinal axis of a broadhead must be aligned with a longitudinal axis of the arrow shaft. Otherwise, the blades can act as airfoils and cause the arrows to plane, which severely affects accuracy. 
     Broadheads often need to be aligned relative to the arrow shaft to insure adequate clearance of the broadhead past the arrow shelf of a bow. In addition, the blades of a broadhead often need to be aligned with the fletching of an arrow and relative to the bow riser. In particular, in connection with broadheads having two bladed designs, it is often desirable to align the blades of the broadhead such that the blades are generally aligned with the riser of the bow. Sometimes, the blades may need to be aligned differently to create the most consistent arrow flight, which is often determined through repeated use. 
     Broadheads are commonly attached to arrows through use of a threaded insert glued into the end of a hollow aluminum or carbon arrow. Broadheads typically include a threaded post sized to be inserted into the insert and tightened down with a broadhead wrench. Once the broadhead is tightened into position, the alignment of the blades of the broadhead is examined. The alignment of the blades may be changed in aluminum arrows by heating the insert to loosen or melt the glue so that the insert may be rotated within the aluminum shaft. Carbon arrows may not be heated because the heat can easily damage the carbon fibers. While heating the arrows enables the inserts to be rotatable within the arrow shaft, repeated heating typically reduces the strength of the glues and often creates poor connections between the inserts and the arrows. 
     SUMMARY OF THE INVENTION 
     This invention relates to a tunable broadhead with a lockable blade assembly capable of being indexed relative to an arrow to which it may be attached for archery hunting. In at least one embodiment, the lockable blade assembly enables one or more blades extending from the lockable blade assembly to be circumferentially positioned relative to a support base attached to an arrow. The broadhead may be formed from a blade assembly that is secured in place by a tip having an elongated engaging shaft that extends through the blade assembly and is attachable to the support base. The support base may in turn be attachable to an arrow. The blade assembly may be rotated into any position before the tip is tightened such that the blade assembly is placed under compression between the tip and the support base. Once the tip has been tightened, the blade assembly does not rotate. Such a configuration enables the blades of the broadhead to be indexed relative to the fletching on the arrow and enables the blades to be oriented consistently between multiple arrows in an archer&#39;s quiver, thereby enhancing accuracy regardless of the position of the insert within the arrow tip to which the broadhead is attached. 
     In at least one embodiment, a broadhead for an archery hunting arrow may include a tip configured to facilitate penetration of the blade into an object. The tip may include a pointed distal end and an elongated engaging shaft extending from a proximal end of the tip. The elongated engaging shaft may extend from the tip and may include a tip connection assembly at a proximal end of the elongated engaging shaft. The broadhead may include a hollow blade support body with at least one blade extending radially outward therefrom, wherein the blade assembly has a central shaft receiving chamber extending therethrough. The broadhead may also include a support base configured to engage a proximal end of the blade assembly. The support base may include a distal support base connection assembly on a distal end that is configured to be attached to the elongated engaging shaft and may have a proximal support base connection assembly on a proximal end of the support base that is configured to be attached to an end of an arrow. The blade assembly may be secured between the tip and the support base with the elongated engaging shaft positioned within the central shaft receiving chamber and engaging the support base. The blade assembly may be rotated about the elongated shaft such that orientation of the blade may be changed to extend from any position circumferentially about the blade assembly. 
     An advantage of this invention is that the blades may be oriented in any position independent of the orientation of the insert within an end of the arrow shaft. Thus, the blades may be oriented in any positioned about a longitudinal axis of the arrow shaft to improve clearance and accuracy. For instance, the blades of three blade embodiments may be aligned with the fletching on the arrow. In other embodiments, such as two blade embodiments, the blades may be aligned to reduce planing upon the broadhead leaving the bow during the initial moments of the shot. 
     These and other embodiments are described in more detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the presently disclosed invention and, together with the description, disclose the principles of the invention. 
         FIG. 1  is an exploded side view of a tunable broadhead of the invention. 
         FIG. 2  is a partially exploded side view of the broadhead of  FIG. 1 . 
         FIG. 3  is an assembled side view of the broadhead of  FIG. 1 . 
         FIG. 4  is an exploded side view of an alternative embodiment of the tunable broadhead shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIGS. 1-4 , this invention is directed to a tunable broadhead  10  with a lockable blade assembly  12  capable of being indexed relative to an arrow  14  to which it may be attached for archery. The broadhead  10  may be formed from a blade assembly  12  that is secured in place by a tip  16  having an elongated engaging shaft  18  that extends through the blade assembly  12  and is attachable to a support base  20 . The support base  20  may in turn be attachable to an arrow  14 . The blade assembly  12  may be rotated into any position, as shown by the arrow  21  in  FIG. 2 , before the tip  16  is tightened such that the blade assembly  12  is placed under compression between the tip  16  and the support base  20 . Once the tip  16  has been tightened, the blade assembly  12  does not rotate. Such a configuration enables the blades  22  of the broadhead  10  to be indexed relative to the fletching on the arrow  14  and enables the blades  22  to be oriented consistently between multiple arrows  14  in an archer&#39;s quiver, thereby enhancing accuracy regardless of the position of the insert within the end of an arrow to which the broadhead  10  is attached. 
     The broadhead  10  may include a tip  16  configured to facilitate penetration of the blade  22  into an object with a pointed distal end  24  and an elongated engaging shaft  18  extending from a proximal end  26  of a head  25  of the tip  16 . The elongated engaging shaft  18  may extend from the tip  16  and may include a tip connection assembly  28  at a proximal end  19  of the elongated engaging shaft  18 . A proximal end  19  of the elongated engaging shaft  18  may terminate within the blade assembly  12 . The elongated engaging shaft  18  and the tip  16  may be a unitary structure. In another embodiment, the elongated engaging shaft  18  and the tip  16  may be separate components attachable via connection system  13 , such as, but not limited to, a threaded connection, as shown in  FIG. 4 . The elongated engaging shaft  18  may include threads to which the tip  16  maybe attached, or vice versa. 
     The tip  16  may be pointed and include any appropriate configuration facilitating penetration of the tip  16  into a target, such as an animal or other target. The tip  16  may taper from a point to a cylindrical aft section or have another appropriate cross-sectional shape. In one embodiment, as shown in  FIGS. 1-3 , the tip  16  may include three cutting arrises  70  that extend from the point  24  and are separated by surfaces  74 . As such, the tip  16  may be is formed from a trocar having a plurality of cutting arrises  70 . The number of cutting arrises  70  may or may not correspond to the number of blades  22 . In one embodiment, the pointed tip  16  may not have any cutting arrises  70 . In other embodiment, the pointed tip  16  may have one or more cutting arrises  70 . The blades  22  may be aligned with the cutting arrises  70 . The tip  14  may be generally cylindrical or have another appropriate shaped outer surface. 
     The broadhead  10  may include a blade assembly  12  formed from a hollow blade support body  30  with at least one blade  22  extending radially outward therefrom. The blade assembly  12  may include a central shaft receiving chamber  32  extending therethrough. The blade assembly  12  may be secured between the tip  16  and the support base  20  by the elongated engaging shaft  18  extending throughout the central shaft receiving chamber  32  and engaging the support base  20 . A distal end  64  of the hollow blade support body  30  may include a tapered outer edge  68  that is configured to mate with a proximal surface  26  of the head  25  of the tip  16 . 
     The broadhead  10  may include a support base  20  configured to engage a proximal end  34  of the blade assembly  12 . The support base  20  may have a distal support base connection assembly  36  positioned on a distal end  38  that is configured to be attached to the elongated engaging shaft  18 . The support base  20  may also include a proximal support base connection assembly  40  on a proximal end  42  of the support base  20  configured to be attached to an end of an arrow  14 . 
     The distal support base connection assembly  36  on the distal end  38  of the support base  20  may have an outer engagement surface  44  configured to engage an inner engagement surface  46  on the blade assembly  12 . The outer engagement surface  44  of the support base  20  may have a conical shape. The inner engagement surface  46  on the blade assembly  12  may have a conical shape that forms a conically shaped chamber sized to receive the conically shaped support base  20 . The size and slope of the outer engagement surface  44  of the support base  20  may match a size and shape of the inner engagement surface  46  of the blade assembly  12 . 
     The tip connection assembly  28  may be formed from threads  48  extending radially outward from the proximal end  19  of the elongated engaging shaft  18 . The distal support base connection assembly  36  on the distal end  38  of the support base  20  may be formed from a cavity  50  having threads  48  extending into a wall  52  forming the cavity  50  at the distal end  38  of the support base  20 . The threads  48  in the support base  20  may match the threads  48  on the tip connection assembly  28  by having the same degree, i.e. fine or coarse, and the same thread pitch. 
     Alternatively, as shown in  FIG. 4 , the tip connection assembly  28  may be formed from a cavity  54  having threads  48  extending into a wall  56  forming the cavity  54  at the proximal end  19  of the elongated engaging shaft  18 . The distal support base connection assembly  26  on the distal end  38  of the support base  20  may be formed from a threaded shaft  58  extending distally from the support base  20 . The threads  48  on the support base  20  may match the threads  48  in the tip connection assembly  28  by having the same degree, i.e. fine or coarse, and the same thread pitch. 
     As shown in  FIGS. 1-3 , the blade assembly  12  may have any appropriate configuration such that one or more blades  22  extend radially outward from the hollow blade support body  30 . The blades  22  may be releaseably or permanently attached to the hollow blade support body  30 . The blades  22  may also be separate elements that are attachable to the hollow blade support body  30 . In another embodiment, one or more blades  22  may be integrally formed with the hollow blade support body  30 . The blade assembly  12  may be formed from one or more blade slots  60  extending between an outer surface  62  of the hollow support body  30  and the central shaft receiving chamber  32  and extending from a distal end  64  of the blade assembly  12  to the proximal end  34  of the blade assembly  12 , but not through the proximal end  34 . The blade  22  may be positioned in one of the blade slots  60  and may extend radially outwardly from the hollow blade support body  30  such that a securing flange  66  extending from the blade  22  extends into the central shaft receiving chamber  32 . The securing flange  66  may be configured as shown in the numerous embodiments disclosed in U.S. Pat. No. 5,482,294, which is incorporated in its entirety by reference herein. 
     The broadhead  10  may be assembled by inserting the elongated engaging shaft  18  into the central shaft receiving chamber  32  until the head  25  of the tip  16  contacts the distal end  64  of the hollow support body  30  of the blade assembly  12 . The tip connection assembly  28  may then engage the distal support base connection assembly  36  positioned on a distal end  38  of the support base  20 . In doing so, the inner engagement surface  46  of the blade assembly  12  is brought into contact with the outer engagement surface  44  of the distal support base connection assembly  36 . The blade assembly  12  may be rotated about a longitudinal axis extending through the elongated engaging shaft  18  to position the blades  22  as desired. Once in the desired position, in at least one embodiment, the tip  16  and attached elongated engaging shaft  18  may be rotated to thread the tip connection assembly  28  to the distal support base connection assembly  36 . Such action causes the tip  16  to press the blade assembly  12  against the support base  20 . In one embodiment, the inner engagement surface  46  of the blade assembly  12  is pressed against the outer engagement surface  44  of the distal support base connection assembly  36 . As the tip  16  is tightened, the head  25  of the tip  16 , together with the support base  20 , places the blade assembly  12  in compression and retains the blades  22  in a desired orientation. The support base  20  may be attached to an arrow in any desired manner, such as, but not limited to being, releaseably or permanently attached. The support base  20  may be releaseably attached via a threaded connection with an insert in the arrow or via a releaseably adhesive. The support base  20  may also be attached via permanent or semi-permanent adhesives and the like. 
     The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention.