Abstract:
A sight pin assembly for an archery bow sight having a shaft portion and a base portion. The base portion is adapted to engage a pin holder on the bow, and has an elongate fiber-receiving aperture therein. The light-gathering optical fiber is engaged by the shaft of the sight pin and has one end closely received in the fiber-receiving aperture. The base portion has a bore which contains a light emitting member. The member is adjacent to the light-gathering fiber.

Description:
This application claims priority from U.S. Provisional Application Ser. No. 60/249,564, filed Nov. 17, 2000, the disclosure of which is hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to sight pins for archery bows, and more particularly to a sight pin having an optical fiber disposed therein that provides an aiming indicia. 
     BACKGROUND OF THE INVENTION 
     Sight pins are commonly used in archery bows, either singly or in multiple units, to provide aiming indicia for an archer. Typically, the pins are vertically adjustable so that the archer can control the vertical position of the aiming indicia as a function of target distance. More recently, light-gathering fluorescent fibers having spaced apart ends at which light gathered along exposed longitudinal surfaces of the fiber is emitted at the ends of the fiber to provide a bright dot, have been mounted in archery pins. The small dots are readily observable when the axis of the end portion of the fiber is aligned with the user&#39;s eye. 
     In previous attempts to mount light-gathering flourescent fibers in an archery pin, one end of the fiber has been mounted in a hole provided in the distal end of the pin and a second end of the fiber has been inserted through a base portion of the pin or received within a groove or ring provided on the base portion of the pin. In these arrangements, the second end of the optical fiber is also exposed. Such arrangements are not only distracting, with two aiming indicias mounted on the same pin being visible, but can actually lead to confusion and distraction, which result in decreased concentration on the correct exposed optical fiber end. 
     Therefore, it is desirable to have an archery pin for a bow in which only one end of an optical fiber is viewable by the archer. It is also desirable to have such a pin in which the light gathering optical fiber emits light that provides a bright aiming indicia even under low light conditions. 
     SUMMARY OF THE INVENTION 
     The present invention is drawn to a sight pin assembly having an optical fiber wherein only one end of the optical fiber is viewable by the archer, and can optionally incorporate a light emitting member to provide a bright aiming indicia under low light conditions. The sight pin assembly includes an elongate pin having a first end and a second end. An elongate light-gathering optical fiber has a first end supported at the first end of the elongate pin such that it is visible when viewing a front of the elongate pin. The second end of the light-gathering optical fiber is supported at a second end of the elongate pin and obscured from view when viewing the front of the elongate pin. 
     The light-gathering optical fiber is received in the second end of the elongate pin. The elongate pin has a cavity in the second end and the second end of the light-gathering optical fiber is received within the cavity. The cavity contains a light emitting member disposed adjacent the second end of the light-gathering optical fiber. The light emitting member may be tritium. At least a portion of the cavity is threaded for attachment to a pin holder of an archery bow sight. The light-gathering fiber enters the second end of the elongate pin at an obtuse angle to an axis of the elongate pin as measured between the second end of the elongate pin and the light-gathering optical fiber. Alternately, the light-gathering optical fiber enters the second end of the elongate pin at a right angle to an axis of the elongate pin. This can be concentric about an elongate cavity which is perpendicular to the axis of the elongate pin. A support fin can extend outwardly from the elongate pin which bridges a space between the light-gathering optical fiber and the elongate pin. The second end of the elongate pin may have a rectangular cross-section. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings, FIG. 1 is a top view of an archery pin assembly embodying the present invention, showing the archery pin assembly secured in a pin holder that is mountable on a bracket that is attachable to a bow, the pin holder being shown in section; 
     FIG. 2 is an end view of the archery pin illustrated in FIG. 3, embodying the present invention; 
     FIG. 3 is a side view of the archery pin illustrated in FIG. 1, embodying the present invention; 
     FIG. 4 is a perspective view of a colored flourescent optical fiber having a clear core; 
     FIG. 5 is a cross-sectional view of an alternate embodiment of the archery pin assembly embodying the present invention; and 
     FIG. 6 is a cross-sectional view of an alternate embodiment of the archery pin assembly embodying the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the illustrated embodiment, a sight pin for an archery bow is generally indicated in the drawings by the reference numeral  10 . The pin  10  shown in FIG. 1 is secured on a pin holder  12  that is attachable to an archery bow, not shown. The pin holder  12  has a vertical slot  14  that permits the pin  10  to be adjusted vertically along the slot  14 . The slot  14  has an enlarged opening  16  at the pin side of a slot that it is sized to intimately receive a square or rectangular shank  18  of a base portion  20  of the pin  10 , and thereby inhibit rotation of the pin  10  within the enlarged opening  16  of the slot  14 . At an opposite end of the slot  14 , an enlarged opening  22  is provided to receive a washer  24  or screw head therein. The pin  10  is adjustably secured to the pin holder  12  by a threaded adjusting screw  26  that engages threads provided in a threaded cavity  28  extending inwardly into the base portion  20  from an end wall  30  of the base portion  20 . Tightening the adjusting screw  26  pulls the base portion  20  of the pin  10  into fixed contact with the pin holder  12 , with the shank portion  18  of the base portion  20  non-rotatably seated and fixed in the slot  14 . By loosening the adjusting screw  26 , the position of the pin  10  can be adjusted vertically whereupon, when the pin  10  is at the desired position, the adjusting screw  26  is again tightened. 
     The pin  10  is conventionally formed of metal, plastic, or a combination of metal and plastic. If a combination one portion of the pin  10 , e.g., the base portion  20 , is formed of plastic and the remaining portion, i.e., a sighting indicia support portion  32  extending outwardly from the base portion, is formed of metal. As described above, desirably at least the base portion  20  of the pin  10  has a square or rectangular external shape to provide flat surfaces that engage the slot  14  whereby rotation of the pin  10  is prevented when the adjusting screw  26  is tightened. 
     A distal end  34  of the support portion  32  has an aperture  36  that is sized to intimately receive a first end  38  of an elongated light-gathering optical fiber  40 . A support fin  41  bridges the space between elongated light-gathering optical fiber  40  and the pin  10  to provide support to the fiber  40 . The support fin  41  can be constructed of either plastic or metal. Light-gathering optical fibers gather light along exposed circumferential surfaces of the optical fiber and focus the gathered light onto the end faces of the fiber. In the present invention, the exposed circumferential surface of the optical fiber  40  is generally indicated by the reference numeral  42 . The light gathered through the exposed circumferential surface  42  is directed to the first end  38  of the optical fiber whereat the end face provides a brilliant dot, especially when the optical fiber  40  has fluorescent properties, for use by an archer as an aiming indicia. Light gathered through the exposed circumferential surface  42  is also directed to a second end  44  of the optical fiber  40 , which is disposed within an end portion  45  of the threaded cavity  28  provided in the base portion  20  of the pin  10 . As best shown in FIG. 1, a portion of the optical fiber  40  adjacent the second end  44  is disposed within an elongated aperture  46  extending between the end portion  45  of the threaded cavity  28  and an external surface of the pin  10 . The elongated aperture  46  is preferably disposed at an obtuse angle α with respect to a longitudinal axis  48  of the threaded cavity  28  to avoid sharp bends in the optical fiber  40 . Thus, the light directed to the second end  44  of the optical fiber is effectively blocked from view by the archer, thus avoiding any distraction or other impediment to the archer from focusing his sole attention on the bright dot at the first end  38  of the optical fiber  40 . 
     To more clearly illustrate the pin  10 , the optical fiber  40  is not shown in FIGS. 2 and 3. However, when the present invention is considered as a pin assembly, the assembly includes not only the pin  10 , but also the optical fiber  40  mounted within the pin as illustrated in FIG.  1 . 
     It should also be recognized that, if desired, a light emitting source, such as a capsule containing a phosphor and a radioactive gas, e.g., tritium gas, could be disposed in the end portion  45  of the threaded cavity  28  at a position adjacent to and touching or slightly offset from the second end  44  of the optical fiber  40 . If the light source is not touching the fiber  40 , a distance of within approximately 0.01 inches is preferred, though greater offsets are operable and within the scope of this invention. Such an arrangement provides an additional light source for use of the pin  10  under very low light conditions when the ambient light gathered through the circumferential surface  42  of the light gathering flourescent optical fiber  40  may be diminished. Further, in situations where a light source is utilized, a clear optical fiber, colored optical fiber, or an optical fiber  40  having a clear core with an colored exposed circumferential surface  42 , for example a colored flourescent cladding, (FIG.  4 ), can be used. When using a light source, the fiber  40  having a clear core and colored circumferential surface  42  is preferred. The clear core ensures maximum transmission of light from the light source through the optical fiber  40  in low light conditions, while the colored circumferential surface  42  produces a colored aiming indicia in moderate to bright lighting. 
     In an alternate embodiment, illustrated in FIG. 5, a pin  10 ′ has a stepped second elongated aperture  50  disposed at substantially a 90° angle with respect to the longitudinal axis  48 ′ of threaded cavity  28 ′. In this arrangement, the elongated aperture  50  extends horizontally through the base portion  20 ′ of the pin  10  with the end of the aperture  50 , facing an archer, plugged with a cap  52  to prevent visual observation of the second end  44 ′ of the optical fiber  40 ′. The cap  52  can thread into the base portion  20 ′ or can be retained frictionally or with an adhesive. Also, the cap  52  can optionally contain a light source  54  which transmits light into the end  44 ′ of the optical fiber  40 ′. In this arrangement, the light source  54  may comprise a vial or bulb containing a phosphor and tritium in a gaseous state. It is preferable that the light source  54  be optically coupled, for example through a lens or transparent glue, or within 0.01 inches of the end of the optical fiber  40 ′ to ensure the optimum transmission of light into the optical fiber  40 ′. Distances greater than 0.01 inches have been found to be operable and are within the scope of this invention. It is also preferable that the centerline of the light source  54  be substantially aligned with the center line of the optical fiber  40 ′ to ensure transmission of light from the light source  54  into the optical fiber  40 ′. 
     FIG. 6 depicts a detail of the pin  10 ′ utilizing an alternate configuration of light source  54 ″. As above, light source  54 ″ can be contained in a cap  52 ″; however, in this embodiment the light source  54 ″ is surrounded by a white protective sleeve  56 . The protective sleeve  56  can be, for example, a polymer material adapted to cushion the light source  54 ″ from impact and prevent breakage. Because sleeve  56  is white, it tends to reflect light from the light source  54 ″ inward toward optical fiber  40 ′. Sleeve  56  can be retained in the cap  52 ″ with an adhesive  62 . 
     Additionally, cap  52 ″ can incorporate a lens  58  between the light source  54 ″ and the second end  44  of the optical fiber  40 ′. Lens  58  can be configured to focus light from the light source  54 ″ into the optical fiber  40 ′. In a preferred embodiment the lens  58  is a hard transparent material, for example a sapphire lens, that in additional to its optical properties, serves to shield the light source  54 ″ from intrusion by the second end  44  of optical fiber  40 ′. Alternately, lens  58  can be an optical connector such as a deposit of transparent silicon, acrylic, glue or other transparent substance that transmits or focuses light from the light source  54 ″ into the fiber  40  and protects the light source  54 ″. 
     Referring again to FIG. 1, a preferred method for assembling the pin  10  with the optical fiber  40  is hereinafter described in detail. One skilled in the art will appreciate that the preferred method of assembly described herein applies to each of the embodiments described herein and depicted in FIGS. 1-6. First, the second end  44  of a length of optical fiber  40  is flared such that the diameter of the optical fiber  40  at the second end  44  is slightly greater that the diameter of the elongate aperture  46 . The first end  38  of optical fiber  40  is then inserted into the elongate aperture  46  from inside the threaded cavity  28 . The fiber  40  is pulled though the elongate aperture  46  until the second end  44  frictionally lodges in the aperture  46 . If needed, an adhesive can be provided on the flared second end  44  to additionally secure the second end  44  in the elongate aperture  46 . Also, the aperture can have a chamfered edge (best seen in FIG. 6 with respect to aperture  50  and chamfer  60 ). One of ordinary skill in the art will appreciate that in an embodiment utilizing a light source  54  (FIGS. 5 and 6) the flared second end  44  can act to collect and direct more light into the optical fiber  40 . 
     With second end  44  secured in the aperture  46 , the first end  38  is then inserted through the aperture  36  in the support portion  32  of the pin  10 . The optical fiber  40  is then trimmed at the first end  38  to an appropriate length. The optical fiber  40  is preferably trimmed to a length that allows the fiber  40  to arc substantially smoothly from the elongate aperture  46  to the aperture  36  of the support portion  32  without kinking. If a support fin  41  is provided, the length of the optical fiber  40  should allow the fiber  40  to rest on the fin  41  substantially without slack in the fiber  40 . Slack in the fiber  40  may allow the fiber  40  to shift and impact and possibly damage the light source  54 . 
     After the optical fiber  40  is trimmed, its first end  38  is then inserted through the aperture  36 . The first end  38  is then flared to be frictionally retained in the aperture  36  of the support portion  32 , and such that the optical fiber  40  is substantially without slack. One of ordinary skill in the art will appreciate that flaring the first end  38  of the optical fiber  40  can increase the size of the brilliant dot seen by the user. 
     It is to be understood that while the invention has been described above in conjunction with preferred exemplary embodiments, the description and examples are intended to illustrate and not limit the scope of the invention. Thus, the scope of the invention should only be limited by the following claims.