Patent Publication Number: US-7717814-B1

Title: Expandable arrow broadhead with spring biased sliding shaft and pointed tip

Description:
This application is a Continuation-In-Part patent application of an application filed on Apr. 24, 2006, Ser. No. 11/410,771, now U.S. Pat. No. 7,226,375 by the subject inventor and having a title of “EXPANDABLE ARROW BROADHEAD FOR ATTACHMENT TO ONE END OF AN ARROW SHAFT. The inventor claims the benefit of the earlier filed application. 

   BACKGROUND OF THE INVENTION 
   (a) Field of the Invention 
   This invention relates broadly to an expandable arrow broadhead and more particularly, but not by way of limitation, to an arrow broadhead having a rotating, sliding shaft received through a hollow collar mounted on a sliding shaft housing. An end of the hollow collar is used for extending outwardly at least two cutting blades, and preferably three cutting blades, upon impact on a target. During arrow flight, the cutting blades are held in a retracted position using a coil spring for biasing the sliding shaft in the sliding shaft housing forward and toward the direction of the target. 
   (b) Discussion of Prior Art 
   Heretofore, there have been a number of arrow broadheads having blades that extend outwardly when contacting a surface of a target. U.S. Pat. No. 6,935,976 to Grace, Jr. et al., discloses a mechanical broadhead having blades, mounted in longitudinal channels in a ferrule, that slide outwardly on a camming surface formed in an inward edge of each blade. U.S. Pat. No. 6,270,435 to Sodaro illustrates an arrowhead having spring loaded blades that expand outwardly upon contact with a target. U.S. Pat. Nos. 6,910,979, 6,626,776 and 6,517,454 to Barrie et al. disclose blades having longitudinal grooves in the blades and a camming member for extending the blades outwardly upon target impact. U.S. Pat. Nos. 6,669,586 and 6,200,237 to Barrie disclose blades mounted on a sliding body mounted on a length of the broadhead. As the sliding body moves rearwardly upon target impact, the blades engage a camming surface and are moved outwardly in an extended position. 
   None of the above mentioned prior art broadhead patents particularly disclose or teach the structure and function of an arrow broadhead having a rotating, sliding shaft with a pointed, scalloped grooved tip and cutting blades attached. The sliding shaft with pointed tip is biased forward during arrow flight by a coil spring mounted inside the sliding shaft housing. The bias force is used to hold the cutting blades in a retracted position. Also, the sliding shaft is designed to move rearward upon target impact with the blades expanding outwardly upon engaging a threaded collar attached to a sliding shaft housing. 
   SUMMARY OF THE INVENTION 
   In view of the foregoing, it is a primary objective of the subject invention to provide an aerodynamic, arrow broadhead that maintains cutting blades in a retracted folded, compact profile position, typically having an in-flight diameter of 0.55 inches, and next to a sliding shaft housing for little or no deflection at target contact. The arrow broadhead flight is similar to an arrow with field tip flight. This feature eliminates the need to adjust sight pins, which is a common complaint of mechanical and fixed broadheads, especially with bows that shoot over 300 fps. The cutting blades are held in the retracted position using a coil spring. The coil spring is mounted inside a collar bore hole in a sliding shaft housing. This feature eliminates the need of using a stretchable band received around a portion of the cutting blades during allow flight. 
   Another primary objective of the invention is using the broadhead&#39;s forward inertia and using a rotating, sliding shaft moving rearward in a hollow collar mounted on a sliding shaft housing, to almost instantaneously upon target contact to move the cutting blades into a fully open and locked position. The forward inertia of the arrow broadhead, the rotation of the cutting blades and the rotation of a spirally wound, scalloped-grooved pointed tip provide for an ultimate penetration of the target. This feature results in larger entry and exit holes, better blood trails and higher game recovery. 
   Yet another object of the broadhead is a unique streamlined, spirally wound, scalloped grooved pointed tip, which rotates during flight and upon target. This feature during flight reduces planning and wind resistance with improved flight accuracy. Also, this feature during target contact provides a drill-like motion for penetration through skin, bone and muscle and then into an animal&#39;s vital organs. 
   Still another object of the invention is the subject broadhead gives a hunter a distinct advantage during an angled shot, which will enter the target without deflection. This feature means the arrow with broadhead will enter the target exactly where it&#39;s aimed, thus resulting in better shot placement, better penetration and more target damage. Most mechanical broadheads can deflect on an angled shot, thereby causing poor penetration and missed vital organs. 
   The subject arrow broadhead includes a sliding shaft with a spirally wound, scalloped-grooved, pointed tip disposed in a front portion of the shaft. The pointed tip is tapered rearward and outward forming a tip base. The tip base includes cutting blade grooves formed therein and parallel to a length of the sliding shaft. The cutting blade grooves are used for receiving a pivot end of two or more of cutting blades. The pivot end of the cutting blades is pinned to sides of the grooves. Each of the blades includes an outer cutting edge and an inner edge. The inner edge of the blades includes a beveled cam surface disposed next to a portion of the length of the sliding shaft. The cam surface includes an inverted “V” shaped locking notch therein. A portion of the sliding shaft is slidably received inside a hollow collar. The collar is attached to a sliding shaft housing. In a retracted position, the blades are disposed next to and parallel to the length of the sliding shaft. The blades are held in a retracted position using a coil spring mounted in a collar bore in the sliding shaft housing and a blade catch extending outwardly from an inner edge of the cutting blades. When the pointed tip engages a target upon impact, the sliding shaft moves rearward sliding inside the collar. As the sliding shaft moves rearward, the blades are released from the blade catch and the beveled cam surface engages a portion of the collar and moves the blades outwardly into an extended position. At this time, the locking notch is received around a portion of the collar for holding the cutting blades in an extended, fixed and locked position during the engagement of the target. 
   These and other objects of the present invention will become apparent to those familiar with the use of arrow broadheads for hunting when reviewing the following detailed description, showing novel construction, combination, and elements as described, and more particularly defined by the claims, it being understood that changes in the embodiments to the disclosed invention are meant to be included as coming within the scope of the claims, except insofar as they may be precluded by the prior art. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings illustrate complete preferred embodiments in the present invention according to the best modes presently devised for it&#39;s practical application and in which: 
       FIG. 1  is a perspective view of the subject arrow broadhead rotating in flight and prior to target contact. The cutting blades with blade catch are shown in a retracted position next to a side of a sliding shaft housing. The sliding shaft housing with attached threaded, hollow collar is shown in cross-section. The sliding shaft housing is used for receiving a portion of a rotating, sliding shaft attached to a pointed tip. A coil spring is shown received inside a collar bore in the sliding shaft housing for biasing the sliding shaft with pointed tip forward and biasing the blade catch against a lower lip of a crown on top of the hollow collar. 
       FIG. 1A  is an enlarged sectional view of a cutting blade with a blade groove for engaging a portion of the crown on the hollow collar for holding the blade in a retracted position during arrow flight. 
       FIG. 1B  is another enlarged sectional view of the release of the cutting blade next to the side of the hollow collar and sliding shaft housing, when the pointed tip makes target contact. 
       FIG. 2  is a perspective view of the arrow broad with the cutting blades released and fully extended into a locked position at target contact. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In  FIG. 1 , a perspective view of the subject aerodynamic arrow broadhead is shown in flight and having general reference numeral  10 . In this drawing, the broadhead  10  is heading toward a target, having a general reference numeral  11 . The flight of the broadhead  10  is indicated by arrow  13 . The arrow broadhead  10  is adapted from mounting to an open end  12  of a hollow arrow shaft  14 . A portion of the arrow shaft  14  is shown in cross section. 
   The arrow broadhead  10  includes a rotating, sliding shaft  16  with a pointed tip  18  formed in a front portion  15  of the shaft  16 . The pointed tip  18  is tapered rearwardly and outwardly forming a tip base  20 . The tip base  20  includes cutting blade grooves  22  formed therein and parallel to a length of the sliding shaft  16 . The cutting blade grooves  22  are used for receiving a pivot end  24  of two or more of cutting blades  26  equally spaced around a circumference of the tip base  20 . In this drawing, two of the cutting blades  26  are shown. In  FIG. 2 , three of the cutting blades  26  are shown and equally spaced around the tip base  20 . The pivot end  24  of the cutting blades  26  is attached to the sides of the grooves  22  using pivot pins  28 . 
   While one or two cutting blades  26  can be used on the broadhead  10 , three cutting blades are preferred. Also, up to five cutting blades could be mounted equally well on the broadhead. 
   It should be mentioned that a key feature of the broadhead  10  is the pointed tip  18  with spirally wound, scalloped grooves  29  therein. The scalloped grooves  29 , during flight and during target contact, provide for rotating the pointed tip  18 , the tip housing  20  with attached cutting blades  26  and the sliding shaft  16 , as indicated by arrows  31 . As mentioned above, this feature during arrow flight reduces planning and wind resistance with improved flight accuracy. 
   Each of the cutting blades  26  include an outer cutting edge  30  and an inner edge  32 . The inner edge  32  of the blades  26  is disposed next to a portion of a length of the sliding shaft  16 . Also, the inner edge  32  of the blades  26  is characterized by having a forward portion  34  with a beveled cam surface  36  and a rearward portion  38 . The rearward portion  38  is also parallel to the length of the sliding shaft  16 . 
   While the beveled cam surface  36  is shown in the forward portion of the blades  26 , it should be kept in mind various cam surfaces can be designed on the inner edge  32  of the blades  26 . Also, the entire length of the inner edge  32  can be sloped slightly upward from front to rear of the blade and provide a cam surface for expanding the blades on target contact. 
   A middle portion  39  of the sliding shaft  16  is slidably received inside and through a hollow collar  40 . The exterior of the collar  40  is treaded or press fitted on a top portion  42  of a sliding shaft housing  44 . The hollow collar  40  acts as a cylinder for allowing the shaft  16  to both slide and rotate therein during arrow flight and during target contact. Also, the arrow shaft  14 , attached to the sliding shaft housing  44 , is free to rotate around the sliding shaft  16 . 
   In another embodiment of the broadhead  10 , the cutting blades  26  can be folded into elongated, parallel grooves along a length of the sliding shaft housing  40 . This feature will provide a smaller and more streamlined profile of the broadhead  10  during flight. This feature of the elongated, parallel grooves is not shown in the drawings. 
   In this drawing, the cutting blades  26  are shown held in a retracted position using a blade catch  45  extending outwardly from a portion of the inner edge  32 . The blade catch  45  is biased against a lower lip of a crown  47  on top of the hollow collar  40 . While the blade catch  45  is shown engaging the hollow collar  40 , it can be appreciated that there is any number of catches or grooves that can be incorporated into the inner edge  32  of the cutting blade  26  and along the length of the sliding shaft housing  44 . 
   The sliding shaft housing  44  includes a collar bore hole  46  with an threaded upper end  48 . The threaded upper end  48  of the collar bore hole  46  is used for threading the hollow collar  40  thereon. Also, the hollow collar  40  can be press fitted in the collar bore hole  46 . Further, the hollow collar  40  can be threaded or press fitted around the outside of the top portion of the sliding shaft housing  44 . The feature of the collar being threaded or press fitted around the outside of the top portion of the sliding shaft housing is not shown in the drawings. 
   In the lower end of the middle portion  39  of the shaft  16  is an annular groove  50  for receiving a ring keeper  52 . The ring keeper  52  prevents the sliding shaft  16  from being removed from inside the threaded hollow collar  40 . While the ring keeper  52  is shown in the drawings, various types of shaft retaining devices such as a threaded nut, key, pin or a widened area in the shaft  16  can be used equally well. 
   Also, the sliding shaft housing  44  includes a smaller, sliding shaft lower bore hole  54  for receiving a lower end portion  56  of the sliding shaft  16 . While the lower bore hole  54  is shown to add strength to the sliding shaft housing  44  for receiving the sliding shaft  16 , the shaft can be shortened and slide only inside the collar bore hole  46 , thus eliminating the need of the lower bore hole  54 . 
   A threaded lower end  58  of the sliding shaft housing  44  is used for attachment to an arrow shaft insert  60  in the hollow arrow shaft  14 . The lower end  58  can also be without threads and attached to the arrow shaft insert  60  in a press fit. Typical, hunting arrows include the arrow shaft insert  60 , therefore, the arrow broadhead  10  can be easily attached to different types of arrows by merely threading the sliding shaft housing  44  into the arrow shaft insert  60  as shown. 
   The collar bore hole  46  includes a coil spring  62 , mounted therein and shown in cross section, and received around the lower end portion  56  on the sliding shaft  16 . The coil spring  62  is biased against the ring keeper  52  for pushing the sliding shaft  16  and pointed tip  18  forward toward the direction of the target  11 . The bias force of the coil spring  62  is indicated by arrow  64 . Also, this bias force  64  urges the blade catches  45  of the cutting blades  26  against the lower lip of the crown  47  on the hollow collar  40 , thus holding the blades  26  in a retracted position during arrow flight. 
   Also in this drawing, the cutting blades  26  are shown with an inverted “V” shaped locking notch  66  formed in the inner edge  32  of the beveled cam surface  36 . The locking notch  66  is disposed in the forward portion  34  of the blade. The feature of the locking notch  66  is important in that when the cam surface  36  slides against a portion of the hollow collar  40  and when the cutting blade  26  is in an extended position, the locking notch  66 , as shown in  FIGS. 1B and 2 , drops into a locked position on a side of the hollow collar  40  thus holding the blade in the extended position. 
   Further shown in this drawing and as an option, the pointed tip  18  can include a removable, razor sharp, replaceable tip  68 . A dulled or damaged tip  68  can be removed and replaced by removing a locking pin  70 . The locking pin  70  is threaded into the tip base  20  and through a lower end portion  72  of the tip  68 . The end portion  72  is received in a groove in the front of the tip base  20 . This end portion  72  is shown in dashed lines. 
   In  FIG. 1A , an enlarged sectional view of a portion of the cutting blade  26  is shown with a blade groove  74  used for engaging a portion of an outwardly extending crown  47  on the hollow collar  40 . In this example, the crown  47  is used for holding the blade  26  in a retracted position during arrow flight. The forward bias force from the coil spring  62  on the shaft  16  and the blade  26  is shown as arrows  64 . Obviously, this is another way of holding the cutting blades next to the side of the sliding shaft housing  44  and in a retracted position. 
   In  FIG. 1B , another enlarged sectional view of a portion of the cutting blade  26  is shown and after target contact. In this drawing, rotating, sliding shaft  16  is moving rearward, as indicated by arrow  76 , in the sliding shaft housing  44 . At this time and as the blade  26  also moves rearward, the blade groove  74  is released from its engagement with the crown  47  of the hollow collar  40 . The cam surface  36  is now sliding along a portion of the crown  47  of the hollow collar  40  and rotating the cutting blade  26  outwardly into an extended position, as indicated by arrow  78 . 
   In  FIG. 2 , the broadhead  10  is shown with three cutting blades  26  in a fully extended and locked position upon contact of the pointed tip  18  on the target  11 . When the pointed tip  18  contacts the target  11 , the rotating, sliding shaft  16  moves rearward with the lower end portion  56  moving into the lower borehole  54  and compressing the coil spring  62  as shown. At this time, the blade catch  45  of each blade  26  is released from the lower lip of the hollow collar  40  and the cam surface  36  begins to ride along the side of the collar until the locking notch  66  drops into a locked position on the hollow collar  40  as shown. As mentioned above, the feature of the use of the coil spring  62  and the blade catch  45  on the blades  26 , or similar releasable securing means, eliminates the need of having to use an external, stretchable band around the blades to keep them in a retracted position during arrow flight. 
   It should be mentioned that should the pointed tip  18  contact a bone rib and be deflected in the target, the hollow arrow shaft  14 , the arrow shaft insert  60  and the sliding shaft housing  44  are free to rotate around the shaft  16  and thus maintain the broadhead&#39;s forward inertia moving through the target  11 . The is an added feature to the broadhead  10  through the use of the sliding shaft  16  in the sliding shaft housing  44 . 
   While the invention has been particularly shown, described and illustrated in detail with reference to the preferred embodiments and modifications thereof, it should be understood by those skilled in the art that equivalent changes in form and detail may be made without departing from the true spirit and scope of the invention as claimed except as precluded by the prior art.