Abstract:
An arrowhead for bowfishing supports pivoting barbs that may refracted rearward to pass through a fish and then extended to retain the fish on the arrow. The barbs provide a truncated stop surface striking a rear of the arrow tip when the arrow tip is tightened on the arrowhead to prevent their forward motion from the extended position when the tip is tightened on the arrowhead and yet to allow such motion when the tip is slightly loosened but not removed. The barbs are offset with respect to their pivot point so that a slight loosening of the arrow tip also allows the barbs to pass forward over the arrow tip for retraction of the fish from the arrow while the tip is retained on the arrowhead.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to arrowheads for hunting and the like and in particular to an improved arrowhead with retractable barbs useful for bowfishing. 
     Arrowheads for bowfishing may have radially extending barbs that swing rearward as the arrowhead passes through the fish, but then open to prevent the fish from slipping off of the arrow when the arrow is retrieved. In order to remove the fish from the arrow after the arrow is retrieved, the barbs may be folded forward over the arrow tip so that the arrow may be pulled backward through the fish. This forward folding of the barbs normally requires releasing a mechanical stop. 
     A first type of mechanical stop is released by, loosening the arrow shaft with respect to the arrowhead holding the barbs, for example, by relative rotation of a threaded coupling between the two. Separation of these components may withdraw a stop surface on the front of the arrow shaft from a stop on the barbs that normally operates to limit rotation of the barbs forward. An example of this type of stop system is shown in U.S. Pat. No. 4,819,360. 
     In a second type of mechanical stop, a threaded connection between the arrow head holding the barbs and the sharpened arrow tip is employed. This type of stop allows the arrowhead to be permanently attached to the arrow shaft. In this stop system, the rear of the arrow tip provides a stop surface that blocks forward rotation of the barbs. Removal of the tip allows the barbs to swing forward to extract the arrow from the fish. An example of this type of stop system is shown in U.S. Pat. No. 7,311,621. 
     In this latter design, the arrow tip, after being removed from the arrow, is subject to being dropped or misplaced as the fish is removed. 
     SUMMARY OF THE INVENTION 
     The present invention provides a barb design for a bowfishing arrowhead that allows the barbs to rotate forward to be extracted from the fish with only a minor loosening of the tip. In this way, the tip is always retained in connection with the arrowhead minimizing risk of loss of the tip during this process of removing the fish. The invention provides a shortened stop surface on the barb that allows the barb to rotate with only minor displacement of the tip together with an offset to the barb arm allowing the barb to swing around the diameter of the tip without interference from the tip when the tip is in place. 
     Specifically then the present invention provides an arrowhead with an arrowhead body extending along an arrow axis between a first and second end. The first end of the arrowhead body may attach to an arrow shaft that may extend rearwardly from the arrowhead body along the arrow axis and a second end may provide a threaded coupling extending along the arrow axis to receive an arrow tip. The arrow tip may be threaded onto the arrowhead body to be movable by rotation between a tightened and loosened position (both as attached to the arrowhead body), the loosened position displaced forwardly with respect to the tightened position. The arrowhead includes at least one arrow barb attached to the arrowhead body to pivot about a pivot axis perpendicular to the arrow axis. The barb may swing between a retracted rearward position extending rearwardly from the pivot axis along the arrow axis, through an extended position extending from pivot point in a direction perpendicular with respect to the arrow axis, and a retracted forward position extending forwardly from the pivot axis along the arrow axis. 
     The arrow barb may include an eye portion attached to an arm portion, the eye portion having a hole about which the arm portion pivots and the arm portion may extend from the eye portion at an offset from a line of radius of a center of the hole so that the arm portion is removed from interference with a rear edge of the arrow tip when the arm portion is in the retracted forward position and the arrow tip is in the loosened position. 
     It is thus a feature of at least one embodiment of the invention to allow removal of the fish from the arrow by moving the barbs to the forward retracted position without completely separating the tip from the arrowhead where it can be dropped or lost. 
     The offset may displace a front edge of the arm portion from the center of the hole by a distance at least equal to a radial distance between the rear edge of the arrow tip and the center of the hole measured perpendicular to the arrow axis. 
     It is thus a feature of at least one embodiment of the invention to allow the barbs to rest against the outer surface of the tip when the tip is loosened. 
     The eye may further include a stop surface abutting a rear end of the arrow tip when the barb is in the extended position and the arrow tip is in the tightened position to restrain pivoting of the barb from the extended position to the forwardly retracted position and removed from abutment with a rear end of the arrow tip when the barb pivots between the extended position and the forward retracted position and the arrow tip is in the loosened position. 
     It is thus a feature of at least one embodiment of the invention to prevent forward retraction of the barbs when the arrow and fish are being retrieved. 
     The stop surface may extend radially in a direction perpendicular to the arrow axis when abutting a rear end of the arrow tip by a distance less than a displacement of the rear edge of the arrow tip between the tightened and loosened positions. 
     It is thus a feature of at least one embodiment of the invention to permit disengagement of the stop surface without removal of the tip. 
     The loosened position may be displaced along the arrow axis by a distance substantially equal to a radial distance between the rear edge of the arrow tip and the center of the hole measured perpendicular to the arrow axis. 
     It is thus a feature of at least one embodiment of the invention to practically reduce the necessary loosening of the tip while providing a robust stop mechanism. 
     The arrow tip may provide a substantially cylindrical rear end and the rear edge of the arrow tip may be an edge defining the interface between a cylinder base defined by the rear end and a cylinder wall defined by surfaces of the arrow tip extending along the arrow axis. 
     It is thus a feature of at least one embodiment of the invention to provide a system that works with standard arrow tips. 
     These particular objects and advantages may apply to only some embodiments falling within the claims and thus do not define the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevational view in partial cross-section of an arrowhead and arrow tip of the prior art showing a stop surface provided by the rear face of the arrow tip against the leading edge of the barb when the tip is fully tightened onto the arrowhead; 
         FIG. 2  is a figure similar to that of  FIG. 1  showing the arrow tip removed such as allows the barb to swing forward without interference; 
         FIG. 3  is a figure similar to that of  FIG. 1  showing the present invention with the tip in the tightened position such as limits forward rotation of the barb in an extended position; 
         FIG. 4  is a figure similar to that of  FIG. 3  showing rearward retraction of the barb with the tip in the tightened position when the arrow is in forward flight; 
         FIG. 5  is a figure similar to  FIG. 3  with the tip in a loosened position but still retained on the arrowhead showing the ability of the barbs to rotate to a forward retracted position; 
         FIG. 6  is a fragmentary side elevational view of a simplified version of the barb and arrow tip showing dimensions allowing operation of the bath; and 
         FIG. 7  is a cross-sectional view along line  7 - 7  of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Prior Art 
     Referring now to  FIGS. 1 and 2 , a prior art arrowhead  10  may provide for an arrowhead body  12  that can attach to an arrow tip  14  by means of the threaded boss  16 . The threaded boss  16  may project along an arrow axis  18  from the front end of the arrowhead body  12  and be received by a threaded bore  20  opening axially into a rear end of the arrow tip  14 . 
     One or more slots  26  extending along the axis  18  may be cut radially into a front end of the arrowhead body  12  each to receive proximal ends of barbs  22 . Within the slots  26 , the barbs  22  are held by roll pins  24  passing through holes in the proximal ends of the barbs  22 . 
     The barbs  22  may pivot about roll pins  24  so as to extend in a direction generally perpendicular to the axis  18  (an extended position) shown in  FIG. 1  where a distal tip  27  of the barb  22  is distant from the arrowhead body  12 . This position may be reached from a rearward retracted position (not shown) where a distal tip  27  of the barb  22  lies adjacent to the outer surface of the rear end of the arrowhead body  12 . Forward pivoting of the barbs  22  from the position shown in  FIG. 1 , with a distal tip  27  extending forward, is prevented by interference between a rear edge  30  of the arrow tip  14  and a stop surface  32  being a front edge of the barb  22 . 
     As shown in  FIG. 2 , with full removal of the tip  14 , barb  22  may swing forward within an exposed extension of the slot  26  passing into the threaded boss  16  until stopped by interference between the stop surface  32  and a rising wall of the slot  26 . This forward retracted position allows removal of the fish from the arrow. 
     The Present invention 
     Referring now to  FIG. 3 , the present invention provides an arrowhead  36  providing an arrowhead body  38  having a rear end  40  that may be attached to an arrow shaft  42 , for example, by means of the cylindrical tendon  44  extending forward from the arrow shaft  42  received by a corresponding cylindrical bore  46  opening axially at a rear end  40  of the arrowhead body  38 . The arrowhead body  38  may be constructed of a metal material such as stainless steel to be resistant from the corrosive effects of water, and in one embodiment may be substantially cylindrical. A suitable material for an arrow shaft  42  may be a composite plastic such as a pultruded fiberglass or other composite material of a type known in the art. 
     An arrow tip  14  may attach at a front end  50  of the arrowhead body  38 , for example, by threading onto a threaded stud  52  extending forward from the arrowhead body  38 . This threaded stud  52  may be received by a corresponding threaded bore  54  opening axially at the rear of the tip  14 . A rear end of the tip  14  may be generally cylindrical and have the same outer diameter as the arrowhead body  38  and may present a rear circular base through which the threaded bore  54  is formed. A rear edge  56  of the tip  14  is defined by an interface between at an outer periphery of the rear circular base of the tip and a cylindrical outer periphery of the rear end of the tip  14 . 
     The tip  14  may be in a tightened position, as shown in  FIG. 3 , with a rear end (base) of the tip  14  abutting a front end of the arrowhead body  38 , the latter which may present a corresponding circular base from which the threaded stud  52  extends. This tightened position may be obtained by rotating the tip  14  clockwise about the axis  18  to tighten the threaded bore  54  about the stud  52 . 
     Alternatively, as shown in  FIG. 5 , the tip  14  can be loosened slightly to be displaced away from a front end of the arrowhead body  38  by displacement distance  59  in a loosened position. This loosened position may be obtained by rotating the tip  14  in a counterclockwise direction about the axis  18  to loosen the threaded bore  54  about the stud  52  and to separate the basis of the arrowhead body  38  and the tip  14 . 
     The front end of the tip  14  may be sharpened to taper to a penetrating point  58  generally aligned with the arrow axis  18 . The tip may be constructed of a machined stainless steel material. 
     Referring now to  FIGS. 3 and 7 , an outer periphery of the arrowhead body  38  may provide for one or more axial slots  60  radially cut into the arrowhead body  38 . One or more barbs  62  may be attached to the arrowhead body  12  by means of an eye portion  64  at a proximal end of the barb  62  having a hole  66 . A hole  66  of each barb  62  may be held in a slot  60  by a roll pin  68  passing through the holes  66  and extending along different axes  70  angularly equally spaced around the arrow axis  18  and perpendicular to the arrow axis  18 . The roll pins  68  may be retained by blind bores cut into the arrowhead body  38 . 
     During use of the arrowhead  36 , the eye portion  64  of a barb  62  may rotate about the roll pin  68  so that a distal end  72  of the barb  62  may fully extend along a perpendicular to arrow axis  18  to an extended position that operates to retain a fish on the arrow shaft  42  or rear end of arrowhead body  38 . When the tip  14  is in the tightened position shown in  FIG. 3 , a stop surface  74  extending upward from the eye portion  64  abuts the rear edge  56  of the tip  14  preventing further forward movement of the distal end  72 . 
     Referring now to  FIG. 4 , although forward motion of the distal end  72  is blocked when the tip  14  is in the tightened position, the barb  62  may rotate rearward so that the distal end  72  moves close to the periphery of the arrow shaft  42  or rear end of the arrowhead body  38  in a rearward retracted position that allows the arrowhead body  38  and barb  62  to pass with low resistance through the fish. In this configuration a proximal arm portion  76  of the barb  62  may lie partially within the slot  60  rearward of the eye portion  64  and be slightly angled with respect to arrow axis  18 , and a distal arm portion  77  may lie more closely parallel to the arrow axis  18  against the outer surface of the arrow shaft  42  or rear end of the arrowhead body  38 . 
     Referring now to  FIG. 5 , when the tip  14  is in the loosened position displaced by distance  59  forward from the arrowhead body  38  on the stud  52 , the barb  62  may rotate to move the distal end  72  to a forward retracted position that allows removal of the fish in a forward direction over the barbs  62 . In this position, a front edge of the proximal arm portion  76  may lie against an outer periphery of a rear end of the tip  14  and the stop surface  74  may be removed from interference with the rear edge  56  so as to allow pivoting of the eye portion  64  forward from the extended position shown in  FIG. 3  to a forward retracted position shown in  FIG. 5 . 
     Generally once the tip  14  has been loosened by at least the displacement distance  59 , it may continue to be loosened over an additional distance without further forward movement of the barbs  62  which are restrained only by contact between the arm portion  76  and the outer periphery of the tip  14 . Some additional forward movement of the barbs  62  may be possible when the tip  14  is fully removed; however, this removal of the tip  14  is not necessary for extraction of the fish over the barbs  62  which are substantially fully in the forward retracted position when the tip  14  is in the loosened position. 
     Referring now to  FIG. 6 , generally the periphery of the eye portion  64  will, over a portion, follow a constant radius  80  about a center  82  of the hole  66  so as to avoid interference in rotation from a bottom of the slot  60  with rotation of the barb  62  from the rearward retracted position of  FIG. 4  through the forward retracted position of  FIG. 5 . 
     When the barb  62  is in the extended position, a stop surface  74  may project upward along a tangent of the constant radius  80  from the periphery of the eye portion  64  by a distance no greater than the displacement distance  59 . When the tip  14  is in the tightened position, the stop surface  74  may be parallel to and abutting a rear face of the tip  14 . In particular, the furthest upward extent of the stop surface  74  may contact the edge  56  to best resist rotation of the barb  62 . When the tip  14  is in the loosened position, stop surface  74  may rotate within a second radius  84  to remain clear from a rear surface of the tip  14  and the rear edge  56 , both being displaced from the first radius  80  by less than the distance  59 . 
     A front edge  86  of the proximal arm portion  76  extends in offset with respect to the eye portion  64 , for example, to extend upward from the eye portion  64  when the barb  62  is in the extended position of  FIG. 3 , along a line displaced rearward along axis  18  from the center  82  of the hole  66  by an offset distance  88 . The offset distance  88  is greater in amount than a tip height  90  being measured perpendicular to the axis  18  from a center of the hole  66  to an outer peripheral edge of the tip  14 . In this way, the barb  62  when moved to the forward retracted position shown in  FIG. 5  may be free from interference with the rear edge  56  of the tip  14  once the tip  14  is displaced by the displacement distance  59 . Front edge  86  may then provide the only contact between the barb  62  and the tip  14  and may touch an outer periphery  85  of the tip  14  well in front of the edge  56  so as to provide a constant limitation in the forward rotation of the barb  62 , even as the tip is further removed, than the displacement distance  59  to the point of removal of the tip entirely. Generally, the displacement distance  59  will be a small portion, for example, less than one quarter, of the length of the stud  52 , ensuring that at the displacement distance  59  and in the loosened position, the tip  14  is still securely held on the arrowhead body  38  by the threaded stud  52 . 
     Referring still to  FIG. 6  anti-vibration features may be added to the tip  14  or to the threaded stud  52  in the form of a polymer insert  92  extending from the threads of the bore  54  to be deformed by the threads of the threaded stud  52  or by means of a slight distortion in the threads  94  of either element according to known locking techniques. Other forms of thread locking can also be employed. 
     Certain terminology is used herein for purposes of reference only, and thus is not intended to be limiting. For example, terms such as “upper”, “lower”, “above”, and “below” refer to directions in the drawings to which reference is made. Terms such as “front”, “back”, “rear”, “bottom” and “side”, describe the orientation of portions of the component within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the component under discussion. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. Similarly, the terms “first”, “second” and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context. 
     When introducing elements or features of the present disclosure and the exemplary embodiments, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of such elements or features. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements or features other than those specifically noted. It is further to be understood that the method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
     It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein and the claims should be understood to include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims. All of the publications described herein, including patents and non-patent publications, are hereby incorporated herein by reference in their entireties.