Abstract:
A broadhead is formed from a ferrule, at least one blade pivotally coupled to the ferrule, and a biasing member positioned under the blade between the ferrule. The biasing member applies pressure upward to a trailing edge of the blade, which is prevented from pivoting forward beyond a pre-determined angle in relation to the ferrule by a point coupled to the ferrule.

Description:
FIELD OF INVENTION 
     The invention relates generally to the field of archery, and more specifically to an archery broadhead with movable blades responsive to external forces. 
     BACKGROUND 
     Bowhunting arrow tips have been in use for years. Typically, bowhunting arrow tips are comprised of broadheads like the Vortex 100-125, Rocky Mountain Snyper, Sonoran 100-125, NAP Spiffire 100-125, Rockets Steelheads 100-125, Wasps Jackhammer 100-125, Game Tracker Silvertip 100, and Ironheads Expandables. 
     The main problem with conventional bowhunting arrow tips is the amount of penetration is insufficient to allow these broadheads to penetrate below-the-surface hard objects (such as hunted animal&#39;s ribs and shoulder blades). The resultant poor penetration creats a high probability for deflection, a high probability for catapulting and needlessly wounding game that cannot be recovered by the hunter. Another problem with bowhunting arrow tips designed to open on impact is the high level of deflection due to ineffectiveness of the blade actuation. Unless the shot is perpendicular to the target, this open, or cut-on-contact design flaw allows the broadhead&#39;s tip and/or blades to divert or steer the arrow off its course, wasting the kinetic energy that should be used for penetration. Another problem with conventional bowhunting arrow tips are in all other broadhead designs to date, very high levels of wedge exist when the blades are actuated to deploy. This occurs because whatever hole or cavity the tip created on impact is now too small for the rest of the body and/or blades to pass through without wedging. Even with perfect conditions and shot placement, the design flaws consume considerable amounts of the arrow&#39;s kinetic energy as frictional heat before some or any penetration occurs. This results in inhumane kills or permanent wounding of game that cannot be recovered by the hunter. 
     While these devices may be suitable for the particular purpose to which they address, they are not as suitable for providing a bow-hunting broadhead that has the ability to penetrate bone and soft tissue deeply and without wedging in the hole created by the tip. 
     In these respects, the anti-wedging broadhead according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing, provides an apparatus primarily developed for the purpose of providing a bow-hunting broadhead that has the ability to penetrate bone and soft tissue deeply and without wedging in the hole created by the tip while conserving the highest possible amount of kinetic energy. 
     SUMMARY OF INVENTION 
     The present invention relates to an archery broadhead that maintains a large broadhead surface area and cutting path while at the same time providing for maximum penetration. The broadhead functions by providing one or more retractable blades pivotally connected to a ferrule. A biasing member is positioned between the blade and ferrule. The biasing member applies pressure upward to a trailing edge of the blade, which is prevented from pivoting forward beyond a pre-determined angle in relation to the ferrule by a point coupled to the ferrule. 
     When penetrating a target, the blade will remain in its maximally extended position unless inward pressure greater than the outward pressure applied by the biasing member is applied to the leading edge of the blade. In such a situation, the blade pivots inwardly toward the ferrule until the broadhead passes through the source of the inward pressure at which time the blade will return to its maximally extended position because the upward pressure applied by the biasing member is greater than any inward pressure applied by an external force. 
     Other features and advantages will be explained in relation to the following embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. Additionally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears. 
         FIG. 1  is a perspective top view of one of many possible embodiments of a broadhead of the present invention; 
         FIG. 2  is a planar side view of the broadhead; 
         FIG. 3  is a planar side view of a ferrule; 
         FIG. 4  is a perspective side view of a blade; and 
         FIG. 5  is a planar side view of a point and ferrule. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is of the best mode or modes of the invention presently contemplated. Such description is not intended to be understood in a limiting sense, but to be an example of the invention presented solely for illustration thereof, and by reference to which in connection with the following description and the accompanying drawings one skilled in the art may be advised of the advantages and construction of the invention. 
       FIG. 1  is a top view of an archery broadhead (broadhead) that includes a ferrule  102 , at least one blade  104  pivotally connected to the ferrule  102 , and a biasing member  106  positioned under the blade  104  between the ferrule  102  and the blade  104  such that the biasing member  106  applies upward pressure to the blade  104 . The broadhead  100  also can include a point  124  detachably connected to the ferrule  102 . A collar  120  can be included at the end of the broadhead opposite the point  124  for holding the biasing member  106  in place relative to the ferrule  102  and blade  104 . A pin can be inserted through an aperture  132  in the ferrule  104  and positioned to receive the blade  104 . The ferrule  102  has a middle blade mounting portion  108 , a shaft engaging end  110  at one end of the blade mounting portion  108 , and an opposed point end  112 . The ferrule  102  can be fabricated from an aluminum alloy, carbon fiber composite material, stainless steel, or other materials such as alternative metals and plastics known to those skilled in the art. 
     The shaft engaging end  110  of the ferrule  102  can include an integral shaft mounting extension  114 , which is comprised of an alignment shoulder  116  and a threaded insertion member  118  extending from the alignment shoulder  116 . The shaft engaging end  110  of the ferrule  102  also can include a collar  120  against which the transverse face of the engaging end of an arrow shaft abuts when the broadhead  100  is secured to an arrow. The diameter of the ferrule  102  adjacent the collar  120  preferably is substantially equal to the diameter of the arrow shaft to prevent an abrupt change in diameter from the ferrule  102  to the arrow shaft that may tend to alter the aerodynamic balance of an arrow-broadhead combination during flight. 
     The collar  120  can be detachable and preferably is adapted to be journaled within a receiving bore contained within an arrow shaft at the engaging end of the arrow. The clearance between the outer peripheral surface of the collar  120  and the receiving bore provides precise alignment of the longitudinal axes of the broadhead  100  and the arrow shaft. The precise alignment of the broadhead  100  with the arrow shaft helps to maintain the aerodynamic balance of a complete arrow-broadhead assembly. The threaded insertion member  118  of the shaft mounting extension  114  is adapted to be received in a cooperating threaded aperture fainted within the arrow shaft. Those skilled in the art will appreciate that there are means other than the mounting extension  114  shown in the figures for engaging the broadhead  100  with an arrow shaft. For example, some broadheads may be provided with a cylindrical extension integral with the ferrule  102  which is adapted for receiving a glue-mounted to broadhead to a cooperating arrow shaft adapted for glue-mounted broadheads. Other broadheads may be provided with a female threaded cylindrical extension integral with the ferrule  102  which is adapted to engage a mating male threaded stud extending from the arrow shaft. Thus the integral shaft mounting extension  114  shown in the figures is provided for illustrative purposes and is not meant to limit the present invention to any specific means for mounting the broadhead  100  to an arrow. 
     The blade mounting portion  108  of the ferrule  102  comprises the majority of the length of the ferrule  102  and is the mounting site of the blades  104 . The blade mounting portion  108  defines a generally circular cross section and includes a forward section  122  which has a uniform diameter. A point  124  comprising a generally cylindrical barrel  126  and a tri-faceted tip  128  can be secured detachably to the forward section  122  of the blade mounting portion  108 . The point  124  can include a plurality of facet faces  130 , and can have various configurations, such as a four faceted or conical point, or other configurations known to those skilled in the art. The facet faces  130  may be planar in configuration or may define a curved surface configuration having an axis of rotation that is perpendicular to the longitudinal axis of the ferrule  102 . 
     The point  124  can include either a fixed or a detachable engaging member for connecting the point  124  with the ferrule  102 . Alternatively, the point  124  can include a recessed receiving portion adapted for mating with the forward section  122  of the ferrule  102 . The point  124  helps secure the blades  104  within the ferrule  102  by providing an adjacent surface beyond which the blades  104  cannot pivot forward. Preferably, the outside diameter of the cylindrical barrel  126  of the point  124  is substantially equal to the outside diameter of the forward section  122  of the ferrule  102 . This provides a smooth transition between the point  124  and the ferrule  102  to insure desirable aerodynamics of the broadhead  100  at the transition point between the point  124  and ferrule  102 . 
       FIG. 2  illustrates more clearly the shape of the ferrule  102 , which can include a rearward flared section  202  defining a varying diameter such that the diameter of the ferrule  102  tapers from the rearward section  202  to the forward section  122 , which has a diameter smaller than that of the flared section  202 . The reduced diameter of the forward section  122  allows for the addition of a detachable point  124  to the ferrule  102  while the flared section  202  provides a gradual transition from the forward section  122  of the ferrule  102  to the arrow shaft. The forward section  122  of the blade mounting portion  108  also defines one or more longitudinally extending recessed portions  204  each adapted to receive a blade  104  and a biasing member  106 . The recessed portion  204  begins at the rear face of the forward section  122  and extends rearward toward the rearward flared section  202 . The recessed portion  204  has a length approximately equal to the length of the blade  104  and a depth sufficient to accommodate the biasing member  106  and to accept the blade  104  if and when the blade  104  is forced downward into the recessed portion  204 . A forward facing section of the recessed portion  204  is adapted for receiving a mounting member  206  which extends transversely across the width of the recessed portion  204 . The recessed portion  204  may be formed by conventional machining techniques known to those skilled in the art. A collar  120  can be placed around the flared section  202  not only to provide a surface against which an arrow shaft can be secured, but also to help maintaining the biasing member  106  within the recessed portion  204 . More specifically, the collar  120  can go around a section of the biasing member  106  that is positioned longitudinally along the length of the recessed portion  202 . 
       FIG. 3  illustrates the recessed portion  204  within the ferrule  102 . The ferrule  102  has a shaft engaging end  110  which includes an insertion member  118  and an alignment shoulder  116 . The rearward flared section  202  of the ferrule  102  tapers and the diameter becomes smaller along the blade mounting portion  108  toward the forward section  122  of the ferrule  102 . The recessed portion  204  is sufficiently long and deep to accommodate a biasing member and a blade when it is retracted due to external forces. 
       FIG. 4  illustrates the front portion of a blade  104  which includes a forward curved section  402  having an aperture  406 . The aperture  406  is positioned around the mounting member to attached the blade  104  to the ferrule. A cutting region  404  of the blade  104  extends rearward from the curved section  402 . 
       FIG. 5  illustrates the relationship of the forward section  122  of the ferrule and the point  124 . The ferrule can include a threaded tip end  208  which receives the point  124  by matching internal threads in the point  124  to threads  210  on the tip end  208  of the ferrule. The point  124  can be removed easily be screwing or unscrewing the point  124  onto or off of the threaded tip end  208 . 
     While the invention has been described at some length and with some particularity with respect to the several described embodiments, it is not intended that it should be limited to any such particulars or embodiments or any particular embodiment, but it is to be construed with references to the appended claims so as to provide the broades possible interpretation of such claims in view of the prior art and, therefore, to effectively encompass the intended scope of the invention. 
     CONCLUSION 
     While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the invention should not be limited by any of the above-described exemplary embodiments.