Patent Publication Number: US-7713151-B2

Title: Mechanical broadhead with expandable blades

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   The present application claims priority to U.S. Provisional Application Ser. No. 60/756,971 filed Jan. 6, 2006. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to a mechanical broadhead for attachment to an arrow and, in particular, to a mechanical broadhead that has blades which are retracted into the body of the broadhead during flight and open upon impact with the target. 
   2. Description of Related Art 
   Previously designed mechanical broadheads that are well-known in the art were constructed to lessen the wind effects on the arrow and to provide a wounding shot that would kill the animal more quickly. There have been various designs that enable the blades to be held in during flight and to expand outward upon impact. The retractable blades in various prior art designs enable the arrow to fly straighter than a fixed blade broadhead because of the elimination of the extended blades that are able to deter the arrow off target (wind plane). Also, as the blades are extended, the intention is to cut a hole that will lead to hemorrhaging, resulting in a faster kill of the target animal. Some of the past designs have put much stress on the blades, which posed the threat that the blades would crack upon striking the target. Also, many of the past broadheads had blades that would extend from the front to the back, which slowed the arrow upon entry and decreased shot inertia, thus creating less penetration. 
   U.S. Pat. No. 6,517,454 to Barrie et al. describes a broadhead body as a single, longitudinally extending passage for receiving blades. The blades are held within their respective grooves with friction holding members which permit rearward sliding movement, resulting in outward expansion. During flight, the blades are not fully contained within the body. 
   U.S. Pat. No. 6,398,676 to Mizek describes a broadhead with blades that can be maintained in a normally closed position, with a major portion of each blade being housed within a slot of the body, and the blades pivoting rearwardly into an open position upon target impact. The blades have a rounded blunt tip portion that initially contacts a target. The arrowhead also contains various types of springs and engaging elements that can be used to maintain the blades in a normally closed position, which also provide a bias force that can be overcome by an opening force applied to the blade when in the closed position. 
   U.S. Pat. No. 6,270,435 to Sodaro describes spring-loaded blades that release and penetrate a target as the target is struck by the arrow. The externally exposed blades are not concealed within the body and are held together by a releasable ring. 
   U.S. Pat. No. 6,015,357 to Rizza discloses a broadhead for use as both an expandable blade head and a fixed blade head. The broadhead is described as a blade assembly that has an elastic ring which extends around the hypotenuse of each blade and in one annular groove in the body when the blade is in the retracted mode, with the tension of the elastic ring and the annular groove chosen determining the amount of force necessary for the blade assembly to achieve an expanded position, and with the blade assembly achieving the expanded position after the blade assembly has entered a prey. The barb on each blade contacts hard tissue causing the three blades to pivot outwardly and backwardly until the base of each blade sits in the associated slot and the elastic ring jumps out of the groove and becomes lodged around the base of each blade, causing the blade assembly to be maintained in the expanded position. 
   U.S. Pat. Nos. 5,112,063, 5,100,143, and 4,998,738 to Puckett and 5,082,292 to Puckett et al. describe broadheads for hunting arrows wherein the broadheads have deployable cutting blades which are held against the broadhead body during flight. U.S. Pat. No. 5,112,063 teaches the use of a tubular restraint for holding the cutting blades against the broadhead body during flight. When the broadhead impacts against an animal, a plunger, which is slidably mounted in the front of the body, is forced into the body and causes the blades to be deployed out of the slots. As the blades are moved out of the slot, the tubular restraint is cut from the body by the cutting edge. U.S. Pat. Nos. 5,100,143 and 4,998,738 teach a broadhead that includes a pair of upper blades and a pair of lower blades which are held within slots in a cylindrical body while the arrow is in flight. Upon impact with an animal, a plunger tip slides into the cylindrical body and upper and lower blades are forced to their open position by acting against the cam surfaces positioned within the cylindrical body. A C-shaped ring performs the function of holding the plunger tip in its extended position in flight and locking the blades in their open position upon impact. U.S. Pat. No. 5,082,292 to Puckett et al. teaches a broadhead with deployable cutting blades which are cammed open from slots in a cylindrical body as the plunger impacts against a game animal. The cutting blades are connected by pivot pins to the plunger. The cutting blades are pivotable when the broadhead is in an open position from the open, cutting configuration, which causes maximum hemorrhaging to a non-barbed configuration. Similarly to the &#39;063 patent, a tubular restraint serves to hold the cutting blades within their respective slots during the flight of the arrow. 
   U.S. Pat. No. 5,102,147 to Szeluga discloses a ballistic broadhead assembly that maintains the blades, pivotably mounted on an actuating plunger, in a retracted condition until impact, thereupon thrusting them outwardly and forwardly for maximum effect, and ultimately constraining them against full retraction in a partially extended, optimal position. An additional pair of fixed blades may be mounted adjacent the rearward end of the body. 
   U.S. Pat. No. 4,932,671 to Anderson, Jr. describes an expandable blade broadhead that has a plurality of blades pivotally mounted on a circular ring. The ring is retained between a cap mounted on a stud extending from the front end of a ferrule and the ferrule. A hardened steel tip is slidably mounted in a bore in the cap, and is formed with a rearwardly facing cam surface. The blades are normally held retracted in slots in the ferrule body and cap, and the tip is normally held in an extended position. When the broadhead impacts a target, the tip is forced rearwardly, forcing the cam surface against the blades pivoting them out of the slots to a rearwardly inclined position. To facilitate extraction, the blades may pivot freely to a forwardly inclined position and the rear edges of the blades are sharpened. 
   U.S. Pat. No 4,099,720 to Zeren describes an expanding arrowhead having pivotally mounted blades within slots of a housing. The blades are retracted for minimum outward extension during flight but expanded and retained in an outwardly extended position upon impact with a target. The blades are retained in the retracted position by frictional engagement with the slots or by frangible or resilient members. Minimal size with maximum blade mounting strength can be obtained by orienting the blade mounting slots within the body in an offset relation to the central axis thereof. The blades are retained by transverse set screws, retaining pins or the like for easy attachment or removal. The blades can be retained in a forwardly oriented direction by a frictional engagement means, an elastic or frangible band, slotted frangible cap, or the like. 
   Each of the above-described previously used arrowheads operate differently and utilize different arrangements for retaining the blades in a retracted position. Some arrangements, which use frictional engagement for retaining the blades, do not appear as though they will work properly. Some arrangements are complex and require a large number of working parts. Other arrangements require specially machined components in order for the blades to deploy properly. What is needed is a simple yet effective design for holding cutting blades of a broadhead in a retracted position during flight and can quickly and effectively deploy these blades upon contact with a target, which is generally capable of use on most broadheads with deployable blades. 
   SUMMARY OF THE INVENTION 
   It is, therefore, an object of the present invention to provide a mechanical broadhead that will address the problems of previous designs and will provide an innovative broadhead for the future. It is another object of the present invention to provide a broadhead that flies like a field tip with no blade exposure, with the blades fully enclosed within the body, but when deployed, the blades lock and enable the broadhead to perform like a fixed blade broadhead. It is a further object of the present invention to provide an efficient broadhead that creates a minimal amount of difficulty when resetting, eliminates the possibility of material breakdown and eliminates the need for disposable parts. It is another object of the invention to provide an overall stronger broadhead by the use of stronger materials and an effective design, thus allowing the transition of kinetic energy from the direct connection of the front tip through the broadhead body into the arrow which enables easier entry into the target without putting the impact on susceptible parts like hinge pins or blades. It is yet another object of the invention to provide non-barbing back-cut on the cutting blades to ease withdrawal of the deployed broadhead from the body of the target. Another object of this invention is to minimize deployment stroke and provide a forward moving blade deployment that will allow a better arrow flight, better transition of kinetic energy from the front tip through the arrow, a more deadly cut when there is not a complete pass through, and minimal inertia reduction upon deployment and entry into the target. Yet another object of the invention is to provide a broadhead front tip design that allows for an increased front load and deeper penetration upon contact with the target. 
   I have invented a mechanical broadhead for attachment to an arrow comprising a broadhead body having a first end capable of removable attachment to an end of an arrow, a second end including a frontal post extending therefrom, and a body portion including a plurality of blade windows formed therein. A retractable blade is attached within each of the blade windows. The blades have a geometrically angled shape and an aperture at one end thereof for attachment within each of the blade windows. A retaining spring retains each of the blades in a retracted position within each of the blade windows. A front body is provided having a frontal end and a rearward end. The rearward end is slidably mounted onto the frontal post extending from the broadhead body. The front body includes at least one aperture extending through a sidewall portion thereof. Connecting members enter through the apertures of the front body and the apertures of each of the blades to slidably secure the front body to the broadhead body and to pivotally secure each of the blades within the broadhead body. A front tip is removably secured to the forward end of the front body, such that upon contact with a target, the front tip and front body slide rearwardly and apply a force into an end of the geometrically angled blades, causing each of the blades to pivot outwardly through the blade window into a deployed position. 
   The current invention reduces stress on the blades, provides an improved cutting design, and has a geometrically unique design for the front tip, front body, broadhead body, cutting blades, and retaining springs to work together. The design of this invention, specifically the geometry of the blade angle and the outside and inside razor edges of the blades in conjunction with the front tip, the front body, and the broadhead body, will provide an improved broadhead that will achieve a better arrow flight, better transition of kinetic energy from front tip through arrow, and a more deadly cut when there is not a complete pass through. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing aspects and advantages will be better understood from the following detailed description of a preferred embodiment of the invention with reference to the drawings, in which the details and drawings are identified as follows: 
       FIGS. 1A and 1B  show perspective views of the broadhead in the loaded and deployed positions, respectively, according to the principles of the present invention; 
       FIG. 1C  shows a perspective view of the individual parts of the broadhead according to the principles of the present invention; 
       FIG. 2A  shows a side view of the broadhead body of  FIGS. 1A-1C ; 
       FIG. 2B  shows a cross-sectional view of the broadhead body taken along line  2 B- 2 B of  FIG. 2A ; 
       FIGS. 3A and 3B  show perspective and side views of the front body of  FIGS. 1A-1C ; 
       FIG. 3C  shows a cross-sectional view of the front body taken along line  3 C- 3 C of  FIG. 3B ; 
       FIG. 3D  shows a cross-sectional view of the front body taken along line  3 D- 3 D of  FIG. 3A ; 
       FIGS. 4A-4H  show various views of a chiseled front tip according to a first embodiment of the invention; 
       FIG. 5  shows a side view of the blade of  FIGS. 1A-1C ; 
       FIG. 6  shows a side view of the retaining spring of  FIGS. 1A-1C ; and 
       FIG. 7  shows a perspective view of the broadhead of the invention in a deployed position including a razor point front tip according to a second embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   For purposes of the description hereinafter, spatial or directional terms shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations, except where expressly specified to the contrary. It is also to be understood that the specific components illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting. 
   Referring now to the figures, there is shown a mechanical broadhead, generally indicated as  10 , capable of attaching to an arrow wherein the broadhead  10  comprises a broadhead body  12 , a front body  36 , a front tip  48 , retractable cutting blades  22 , retaining springs  28  and connecting members  46 , such as screws. 
   More specifically, the broadhead  10  comprises a broadhead body  12  having a first end  14  capable of removable attachment to an end of an arrow (not shown), a second end  16  including a frontal post  18  extending therefrom, and a body portion including a plurality of blade windows  20  formed therein. The retractable blade  22  is attached within each of the blade windows  20 . The blades  22  have a geometrically angled shape, at an end  27 , as shown in  FIG. 5 , and an aperture  24  at a front end  26  thereof for attachment within each of the blade windows  20 . The retaining spring  28  retains each of the blades in a retracted position within each of the blade windows  20 . The first, or rear, end  14  of the broadhead body  12  has a threaded rear shank that enables the broadhead  10  to be screwed onto the arrow shaft. The broadhead  10  weight was reduced by fluting excess aluminum out of the broadhead body  12 . 
   The front body  36  is provided having a frontal end  40  and a rearward end  38 . The rearward end  38  is slidably mounted via an opening  39  onto the frontal post  18  extending from the broadhead body  12 . The frontal post has an approximately .125″ diameter that inserts into the rearward end  38  of the front body  36 . The opening  39  includes a shoulder  37  that extends around the opening  39 . The front body  36  includes at least one aperture  42  extending through a sidewall portion  44  thereof. Connecting members  46 , such as screws, pins and the like, enter through the sidewall apertures  42  of the front body  36  and the apertures  24  of each of the blades through apertures  68  in the broadhead body  12  to slidably secure the front body  36  to the broadhead body  12  and to pivotally secure each of the blades  22  within the broadhead body  12 . The geometrically angled end  27  of the blades  22  contacts the shoulder  37 . Apertures  42  in the front body  36  have an elongated shape, preferably an approximate 20 degree twist, to permit movement of the front body  36  with respect to the broadhead body  12 . Upon application of a rearward force to the front body  36 , the 20 degree pitch for the aperture  42  causes a twisting action of the front body  36  with respect to the broadhead body  12 . This twisting action cooperates with the geometrically angled blade end  27 , which is in contact with the shoulder  37 , to cause the blades  22  to a twisting pivot about connecting members  46  in an outward direction with respect to the broadhead body  12 . 
   The front tip  48  is removably secured to the frontal end  40  of the front body  36 , such that upon contact with a target, the front tip  48  and front body  36  act as one to slide rearwardly into an end  27  of the geometrically angled blades  22 , applying a force as depicted by arrow “A” in  FIG. 5 , thus pushing each of the blades  22  outward, in a direction as depicted by arrow “B” in  FIG. 5 , through the blade windows  20  into a deployed position. 
   Once the front tip  48  and the front body  36  are slid rearwardly onto the broadhead body  12  and the blades  22  deployed, the front tip  48  and the front body  36  are solidly compacted, thus conveying kinetic energy from the front tip  48  and front body  36  into the broadhead body and into the arrow shaft. This total mechanical deployment function is carried out within 0.050″ from the time of target contact to complete deployment. While the drawings show the aperture  42  having a 20 degree twist, one having ordinary skill in the art would recognize that a straight aperture may be used in place of an angled aperture. 
   Preferably, the broadhead body  12  includes three windows  20  and associated blades  22  located diametrically at 120 degrees around the body  12 , as depicted in the cross-sectional view of the broadhead body  12  of  FIG. 2B . The front body  36  is secured to the broadhead body  12  through the use of three separate connecting members  46  which are positioned through apertures  42  which are also located diametrically at 120 degrees around the front body  36  and corresponding apertures  68  which are positioned around the broadhead body  12 . The three connecting members  46  continue through the apertures  42  in the front body  36  and the apertures  68  in the broadhead body  12 , thus continuing through the geometrical/hinging end apertures  24  of the cutting blades  22  and securely connecting into the inner core of the broadhead body  12  through assembly apertures  68 . 
   Once the cutting blades  22  are inserted into the broadhead body  12  with the geometrical end  27  of the blades  22  protruding from the top of the broadhead body  12 , the assembly, consisting of the front tip  48  and the front body  36 , will be slid over the end of the frontal post  18  of the broadhead body  12  and the cutting blades  22  will be secured in position with three connecting members  46 . Connecting members  46  will be flush with the sidewall  44  of the front body  36 . A hole  45 , capable of receiving an Allen wrench, is formed in the connecting member  46  to enable one to disassemble the broadhead. 
   Preferably, the front body  36  has a triangular shape. The blade windows  20  and blades  22  are positioned in alignment with apexes  74  of the triangular shape of the front body. The triangular shape of the front body minimizes weight of the broadhead  10  and aids in the aerodynamic flight of the broadhead. Cut-out openings  47  are provided in the rear end  38  of the front body  36  which are elongated in shape, and contact a notch  65  to assist in the deployment of the blades  22 , to permit a portion  66  of the blades  22  to extend therethrough when the broadhead  10  is in the deployed position. 
   The blade windows  20  accommodate blade deployment and have a size and shape such that when the front tip  48  is in a loaded position and the blades  22  are detracted, the blades  22  are completely contained within the broadhead body  12 . The blade movement out of blade windows  20  into the deployment position is such that it minimizes drag and resistance on impact with the target and allows deeper penetration. 
   Each of the blades  22  is held within the broadhead body  12  during flight by associated retaining springs  28 . For each retaining spring  28 , the broadhead body  12  includes pairs of retaining spring holes  70 ,  72 , as shown in  FIG. 2A . The retaining springs  28  mount into the broadhead body by the respective retaining spring holes, one rearward  72  and one forward  70 . As shown in  FIG. 6 , each of the retaining springs  28  comprises a stainless steel straight spring wire having an approximate 90 degree angle bend at the rear end  32  of the retaining spring  28 . A slight arcuate offset is provided on the rear end  32  of the spring thus forming a friction fit within the rearward retaining spring hole  72 . This design creates a downward force on a front end  30  of the spring that is contacting the side of the cutting blade  22  through the forward hole  70 , wherein the pressure produced by the spring  28  creates a resistance factor that will hold the blade  22  snugly within the broadhead body  12  to prevent the blades  22  from deploying on shot inertia and, upon contact, adequate shot pressure on the front tip  48  that will allow the blades  22  to slide out from under the retaining springs  28 . The front of the retaining springs  28  are bent at an approximate 90 degree angle to snap in behind the blades  22  thus locking them open. 
   As shown, particularly in  FIG. 5 , the cutting blades  22  have a slight radial notch  65  on the front cutting edge of the blade  22  to avoid contact with the rear end  38  of the front body  36 . As discussed above, the opening  47  is provided in this rear end  38  of the front body to accommodate a portion  66  of the blade  22  extending out from the broadhead body  12  during deployment. The blades  22  are comprised of stainless steel that has been ground on both sides of the blade  22  for sharpness and are geometrically designed to hinge into deployment when force is applied to the frontal hinge end of the blades  22 . The blades  22  have a cutting surface on both outside and inside edges  62 ,  64  of the blade such that the outside edge  62  of the blade  22  will cut on forward entry into the target and the inside edge  64  of the blade  22  will create a back cut upon removal of the blade from the target. This will allow for a greater amount of hemorrhaging of the wound and a quicker kill of the target, hence reducing suffering of the target. 
   As shown in  FIGS. 1A-1C  and particularly in  FIGS. 4A-4H , the front tip  48 , according to a first embodiment, comprises a sharp three-sided chisel point  50  containing a threaded shaft  52  that is removably secured within a threaded opening  41  of the frontal end  40  of the front body  36 . This chisel point  50  can be formed from stainless steel, titanium or any other known material having sufficient strength characteristics to obtain efficient penetration into the target and create sufficient front-end load which enables broadhead deployment. Preferably, chisel point  50  includes balled out portions  76 . These balled out portions  76  may be formed, for example, by the application of ball mills into the tip  48 . These balled out portions  76  form a “shelf”  78  which is at an approximate 90 degree angle behind the point  50  to increase the front end load of the broadhead  10  upon contact with the target and allow for a deeper penetration of the broadhead  10  into the target. This is achieved because, upon impact with the target, the shelf  78  forms a “bubble” around the front tip which retards the motion of the broadhead  10  enough to apply a backward force or front end load to the front body  36  such that is causes the blades to deploy after the front tip  48  has deeply penetrated the target. In other words, the shelf  78  on the front tip  48  acts as a “snowplow” behind the chisel point  50 , allowing for a deep penetration of the broadhead  10  into the target before deployment of the blades  22 . 
   According to a second embodiment, as shown in  FIG. 7 , the front tip  48  may comprise a cut-from-the-start razor tip or a two-sided razor  54  containing a threaded shaft that is removably secured to the front body  36 . In this embodiment, the razor  54  may be enclosed within a cone-shaped sacrificial plastic sleeve  56  wherein the plastic sleeve  56  breaks off upon contact with the target. 
   The broadhead  10  of the present invention may be reset by simply inserting a sharp object, such as a knife tip, under the front end  30  of the retaining spring  28  and using a screwdriver twisting type motion, as depicted by arrow “C” in  FIG. 6 . This twisting motion will allow the spring  28  to slide out from behind the blade  22  allowing it to retract back into the broadhead body  12  and into the loaded position. The tip of the front end  30  of the spring enters through the front hole  70  of the broadhead body  12  to contact the side of the blade  22 . This front end tip of the spring applies a frictional force to the blade  22  to maintain it in a retracted position. Upon application of a rearward force to the front tip  48  and front body  36 , the front body  36  slides rearwardly to cause movement of the blade  22  to overcome the frictional force applied thereto from the tip of the front end  30  of the retaining spring  28 . This causes the blades to deploy and the tip of the front end  30  of the retaining spring  28  to snap into place beneath the blade  22  and maintain the blade  22  in the deployed position. The blade  22  cannot be retracted until the front end  30  of the retaining spring  28  is manually lifted from behind the blade  22  and the blade  22  is then manually pushed back into the blade window in the loaded position. 
   While the figures depict a three-bladed broadhead device, two or even four or more bladed designs can be encompassed by the present invention. The current invention reduces stress on the blades, provides an improved cutting design, and has a geometrically unique design for the front tip, front body, broadhead body, cutting blades, and retaining springs to work together. The design of this invention, specifically the geometry of the blade angle and the outside and inside razor edges of the blades in conjunction with the front tip, the front body, and the broadhead body, will provide an improved broadhead that will achieve a better arrow flight, better transition of kinetic energy from front tip through arrow, and a more deadly cut when there is not a complete pass through the target. Additionally, the three-sided chiseled tip allows for a great front end load and deeper penetration of the broadhead into the target prior to deployment of the blades. 
   Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of this description. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.