Abstract:
The visibility of an arrow after it has been fired is increased by illuminating arrow fletchings in which light injected into the nock is further injected into the fletching.

Description:
FIELD OF THE INVENTION 
     This invention relates to increasing the visibility of an arrow after it has been fired by illuminating the fletchings of the arrow. 
     BACKGROUND OF THE INVENTION 
     As described in U.S. Pat. Nos. 4,340,930; 6,364,499; 7,021,784; 7,837,580; 7,927,240; 7,931,550; and 7,993,224, what is shown is the utilization of lighted nocks to find an arrow once it has been fired. Note further that a related case U.S. patent application Ser. No. 13/101,137, now published as U.S. 2012/0100942, also describes a prior art nock light and assembly. 
     In addition to the above-mentioned patents there is a product brand called Nockturnal™ manufactured by the Assignee hereof in which a lighted nock is actuated upon firing to inject light into the nock itself. 
     The problem is there is insufficient light to be able to see the nock under all conditions, especially for instance when the arrow goes into a leaf pile. The reason is that the light from these nocks are primarily transferred out the back of the nock and not significantly from the side. 
     Thus, in the past lighted nocks have been visible from the rear but not from the side and when they end up in the forest under leaves and the like they are often not retrievable because they cannot be seen from any distance, especially when the nock itself is obscured. 
     It will be appreciated that in the prior art nock lights include an LED assembly and battery which is secured within the arrow shaft or bolt in which the LED light has a hemispherical dome projecting into the transparent nock. In several of the abovementioned patents the light is turned on or activated when the bow string presses against a plunger or pin which forces the LED assembly into contact with battery contacts to turn on the nock light. Other methods of turning the LED on also exist in prior art such as incorporating an accelerometer, or other subassembly motion caused by the string motion; all of which could be used with the innovations in this patent application to produce lighted fletchings. 
     SUMMARY OF INVENTION 
     In order to provide more visibility for an arrow that has been fired, the aforementioned nock lights inject light into translucent fletchings such that the light that is injected into the nock is also injected into a portion of the fletching. As a result the fletching not only projects light towards the back of the arrow in the direction of the hunter but also causes the fletchings to glow and thereby be visible. 
     The key to the subject invention is that the light from the nock is transmitted into the fletchings because they are mounted on the arrow shaft such that light from the LED enters a bottom edge of the fletching. Thus in one embodiment the fletchings are partially on top of the nock such that the trailing end of the fletchings is illuminated by nock illumination. 
     Also because it is not desirable to have too much light coming from the front of the fletchings, in one embodiment the fletchings are two piece fletchings that are comolded. The forward portion of the two piece fletching is opaque or colored. The trailing edge of the forward portion has a parabolic shape for reflecting light back toward the rear clear piece of the fletching that then lights up for the hunter. 
     The interface between the opaque portion and the transparent portion of each of the fletchings is parabolic in one embodiment so that light that comes from the nock light goes into the fletching and is reflected back along the axis of the arrow or bolt so that it provides a brighter rear view for the hunter. 
     In one embodiment the LED light and battery assembly are contained at the trailing edge of the arrow adjacent a clear polycarbonate nock. In this embodiment the clear polycarbonate nock has a raised lip portion that physically engages a clear under edge of the fletchings so as to be able to transmit light from the LED injected into the lighted nock into the fletchings. 
     The fletchings in one embodiment are formed from a molded piece of clear urethane which has good light transmission capability but has also elastomeric properties such as to enable it to be press fit onto the polycarbonate nock to establish a robust interface between the polycarbonate nock and the urethane fletchings. As a result there is minimal light transmission lost across this interface. 
     While it is not required that the fletchings have an opaque or colored forward portion with a parabolic interface between the colored portion and the transparent portion, the fletchings themselves may be co-molded in two parts such that the rearward portion of the fletching is molded onto the forward portion of the fletching which is an opaque piece of urethane. In such a co-molded embodiment the trailing portion of the fletchings is clear and is optically transparent as possible a urethane fletching. In the comolding process the same tool may be utilized to establish threshold integrity between the opaque portion and the transparent portion of the fletching. The interface between the opaque portion at the front of the fletching and the clear piece at the back of the fletching functions to reflect light that is introduced into the fletching back along the axis of the arrow or bolt. Thus, any light that gets into the fletching reflects off the front opaque portion and is transmitted across the interface out the back of the fletchings. 
     Because the urethane utilized in the fletching does not have 100% optical transparency light will scatter within the fletching to cause a significant amount to come out the side of the fletching as fletching glow as well as exiting from the rear of the fletching. 
     The result is that not only is a large majority of the light transmitted back towards the hunter so that he can see where his arrow has landed, the light is also scattered to the side causing the fletchings to exhibit a glow which is readily visible from all angles when a hunter is looking for his arrow. 
     Note that when the light emitted diodes are utilized, the LED lamps typically have a hemispherical cover. There is also an annulus in the nock that extends out from the nock, such that any light that comes out of the hemisphere goes straight back through the nock and also goes sideways through the annular portion of the nock in an orthogonal direction. Thus light is injected into clear nock and goes into the fletching at the rear portion of the fletching thus to inject light into the fletching. While a hemispherical light cover is not required to enable light transmission into the fletchings and nock, it is one embodiment that can achieve such function. Other shapes of light cover could be used as well, as long as they allow light to transmit both to the rear and the sides of the nock to allow simultaneous lighting of fletchings and nock. 
     A hemispherical light cover is the preferred embodiment because the LED in essence produces a ring of light at the nock, with a portion of the fletching on top of the ring. 
     One of the unique characteristics is that the fletching simply extends back onto the nock, with the majority of the fletching still forward on the arrow. Thus there is no contact between the majority of the fletching and the nock. The overlap in one embodiment is approximately one-fifth of an inch which is enough to take light that is propagating into the nock barrel and transmit it into the overlying edge of the fletching. 
     The result is that while a large portion of the light exits the nock in the usual fashion, since the fletchings are not 100 percent transparent not all of the light is transmitted out the end of the nock but rather into the fletchings which results in a glowing fletching. 
     When the parabolic interface is utilized between opaque portion and transparent portions of the fletching a significant amount of the light is refracted and bent and bounced around inside the fletching such that a not small amount of the light exits the side of the fletching causing the fletching to glow and therefore be perceivable by the hunter. 
     In summary, an arrow or bolt is provided with a LED battery-powered module in which the light from the LED is transmitted up into transparent fletchings whereupon the fletching are made to glow from the side as well as to provide a large amount of light back towards the hunter along the axis of the arrow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features of the subject invention will be better understood in connection with the Detailed Description, in conjunction with the Drawings, of which: 
         FIG. 1A  is a diagrammatic representation of an arrow buried in leaves after having been fired at a deer, wherein in  FIG. 1B  a light emitting diode within the arrow illuminates the fletchings such that they glow due to an overlap between the bottom edge of the fletchings and an associated lighted nock; 
         FIG. 2  is a diagrammatic illustration of the arrow of  FIG. 1  in which light from an internally carried LED is injected into the fletchings; 
         FIG. 3  is a diagrammatic illustration of the lighted fletchings of  FIG. 2  in which a bow string activates the internally carried LED through a plunger assembly that turns on the LED; 
         FIG. 4  is an exploded view of the lighted fletching of  FIGS. 1-3  illustrating that the fletching overlies the battery/LED assembly, also showing a pin which pushes on the LED to connect the LED to the battery, also showing an aperture in the nock which permits transmission of the light from the LED into the fletchings; 
         FIG. 5  is a diagrammatic illustration of the completed lighted fletching assembly of  FIG. 4  illustrating one embodiment in which apertures in the nock permit light from a lighted ring within the nock to exit into the fletchings; 
         FIG. 6  is a diagrammatic illustration of one embodiment of a nock utilizable for crossbows in which the crossbow bolt is provided with the assembly of  FIG. 4 , but with a metal retaining system utilized to secure and control the lighted nock such that upon impact of the crossbow string the nock is not shattered; 
         FIG. 7  is a diagrammatic illustration of the radiation pattern from the rear of the lighted nock showing a subtended angle of about 90 degrees; with additional light transmitted from side apertures to illuminate the fletchings and therefore increase the angle from which the assembly would be readily visible. 
         FIG. 8  is a diagrammatic illustration of the two part fletching assembly illustrating the opaque or colored portion of the fletching that provides a parabolic interface between the opaque and transparent portions of the fletching at the rear; 
         FIG. 9  is an exploded view of the system of  FIG. 8  showing the lighted nock having an aperture which when inserted into a cylindrical channel in the fletching aligns the rearward portion of the fletching with the light emitted from the lighted nock, thus to illuminate the fletchings; 
         FIG. 10  is a diagrammatic illustration of the completed fletching nock light assembly of  FIG. 9  in which light from the aperture enters the rearward portion of the fletchings and is reflected by the parabolic surface backwards towards the hunter as well as exiting to the side of the fletchings; 
         FIG. 11  is an exploded view of the interconnection of the forward portion of the fletchings which is opaque versus the transparent rear portion of the fletching, illustrating the interlocking connection between the two portions of the fletching; 
         FIG. 12  is a diagrammatic illustration of a nock light assembly in which rather than having a notch in the nock, the nock is provided with a flat impact surface which nonetheless activates the internally carried nock light module to emit light around a ring beneath the apertures; with this embodiment being commonly used for crossbows; and 
         FIG. 13  is a diagrammatic illustration of the utilization of a pin actuated LED light assembly, with the pin depressed against the top of the dome of the LED to push the assembly forwardly upon impact with the bow string that in turn turns on the LED. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIG. 1A , an arrow  10  is shown having been fired at an animal  12  which has missed the animal and lies in the underbrush or leaves  14  that are obscuring the arrow from view of the hunter. The arrow as illustrated in  FIG. 1B  is provided with a lighted nock  16  which is only visible over a small angle directly behind the arrow such that the arrow, which may be hidden by the underbrush or leaves is not visible to the hunter and is therefore not subject to retrieval. On the other hand the fletchings  20  of the arrow are lighted from light injected into the nock so that they are extremely visible. 
     Referring to  FIG. 1B , arrow  10  is provided with lighted fletchings  20  that overlie lighted nock  16  and which glow when the lighted nock is actuated. This glow is visible not only from the rear but also from the sides of the arrow making the arrow visible from all angles so that the arrow may be retrieved. 
     Referring to  FIG. 2 , what can be seen is that arrow  10  is provided with transparent fletchings  20  that are affixed over a lighted nock  22  which has a plunger  24  to activate the internally carried battery/LED assembly as is common. Here it will be appreciated that nock  22  is lighted so that the light from the nock is visible from the rear of arrow  10  as illustrated by arrow  26 . Simultaneously light which is refracted within the fletchings is directed outwardly as illustrated at  28  so that the fletchings are made visible from the side of the arrow in terms of a glow. While  FIG. 2  shows an embodiment with a plunger style lighted nock activation, other means of activating the LED light such as an accelerometer or movable subassembly would serve equally well in this case. Any means used to light the nock, can be used to light the fletching by having them overlap and transmit light between them. Alternatively, if the light is either molded into the fletching, or placed directly into the fletching, light from the fletchings could be transmitted to the nock and therefore light the nock. Lastly, it will be apparent that both the fletchings and nock could have a lighting source as well. 
     This is more clearly shown in  FIG. 3  in which as light  28  is visible to the side of the arrow after the arrow light emitting battery module has been activated when bow string  30  depresses pin  24  of  FIG. 2 . For the other embodiments that don not have a piston, or plunger, the motion of the string can be used to turn the light on in their respective fashions. In another embodiment the light is turned on prior to engagement with the string. In other words, the light activation and de-activation need not be controlled by the string and could be independently controlled. The key to the subject invention is that both the fletchings and the nock would be lit, preferably, but not necessarily, from one light source; and preferably, but not necessarily, string activated. 
     Referring to  FIG. 4 , an exploded view of the lighted fletching assembly is illustrated in which a cylindrical carrier  30  is slipped over arrow shaft  32 , with a battery LED assembly  34  is slipped within a cylindrical channel  36  on which fletchings  20  are carried. An activation pin, here shown at  24  contacts dome  36  of LED  40  to connect LED  40  to battery  42 . Assembly  34  is contained within a sleeve  44  of lighted nock  22 , with lighted nock  22  being provided with a number of holes or orifices  46  about the periphery of nock shaft  48 . In this way light which is omitted from dome  36  exits orifices  46  and is injected into the trailing edges of the fletchings. Nock  22  need not have holes  46  in its periphery if nock  22  is made of transparent or semi-transparent material such as polycarbonate, or clear ceramic. When nock  22  is made of transparent material, light from the LED subassembly  34  transmits through the nock body into the overlapping cylindrical carrier  30  and hence into fletchings  20 . 
     Referring now to  FIG. 5 , what is shown is the structure use in crossbow applications in which a nock is surrounded by a metal cylinder to prevent nock fracture during bow string slap. Here orifices  46  are provided through a metal support  48  for nock  22 . It will be seen that nock  22  is provided with an annulus  50  which captures the light from a dome shaped LED and transmits it through orifices  46  into the trailing edge of overlying fletchings. 
     As shown in  FIG. 6 , when a lighted nock is to be provided for a cross bow, a metal support  48  can be used to surround lighted nock  22  to prevent the nock and associated assemblies from shattering due to the close to 7000 psi that is exerted on the nock when a cross bow is fired. 
       FIGS. 5 and 6  are another embodiment that is suitable for some models of crossbow. Any style of crossbow nock would be suitable, so long as light is transmitted from the nock body either directly or via openings to the fletchings. Alternatively, light could be generated in the fletchings and transmitted to the nock, or light could be generated in both. The preferred embodiment would be to light the nock and transmit light to the fletchings. 
     Referring to  FIG. 7 , the light emitted from the lighted nock  22  is shown to exit in a cone  56  that subtends an angle  58 , for instance of 90 degrees. This cone while being visible to a hunter who is directly aft of the arrow is not easily seen when the arrow lands with its longitudinal axis facing away from the hunter. As noted above, light can be channeled to orifices or holes on the side of the nock to an overlapping fletching assembly to then light the fletchings and therefore increase the angle from which the assembly is visible. 
     Referring now to  FIG. 8 , the fletching assembly  20  of  FIG. 4  is shown in which the fletchings are mounted on cylindrical carrier  30 , with the fletchings in this embodiment having two parts. The first part is the forward part  60  which is opaque or colored and has a parabolic rear interface surface  62  in one embodiment such that when the transparent rear portion  64  abuts the forward portion light that enters the transparent rear portion is reflected aft as illustrated by arrow  66  to the extent that light impinges upon parabolic interface  62 . The interface is not required to be parabolic and could suitably be made in any suitable shape or combination of shapes to reflect light primarily out the rear of the fletchings. This could include a hyperbola, a spherical, a surface trapezoid or other multi-faceted shape. 
     Referring to  FIG. 9 , the opaque portion  60  is shown with the preferably parabolic interface at  62  and with the transparent portions  64  of the fletchings clearly illustrated. Also shown is a nock extension  44  adapted to fit into cylindrical fletching assembly  30  which communicates with orifice  46  in lighted nock assembly extension  44  such that light from orifices  46  of  FIGS. 4-6  enters into the lighted nock assembly when it is press fit into the cylindrical interior portion of assembly  30 . As can be seen light  76  exiting orifice  46  bounces off the parabolic interface and is reflected back along the longitude center line of the arrow as illustrated at  78 . If nock  16 , nock assembly extension  44  and assembly  30  are made of transparent material, there need be no exit orifices from the nock, as light will escape from nock assembly extension  44  into the press fit transparent inner cylindrical portion of assembly  30  and thence into the fletchings. 
     Referring to  FIG. 10 , when the two portions of the fletchings are joined together namely portions  60  and  64  the preferably parabolic surface  62  is such that it reflects light from orifice  46  or annulus  70 , back out along the center line of the arrow. The forward portion of the fletching  60  is preferably opaque to light, while the rear portion  64  is preferably transparent or nearly so. The two portions  60  and  64  can be mechanically and/or chemically bonded together. In the preferred embodiment, one portion is injection molded, followed by co-molding or insert molding of that piece into a single unit in which both parts are inherently and permanently bonded to one another. 
     In the assembly of the two part fletching the forward part of the fletching  60  is illustrated having fletching portions  62  mounted to assembly  30 , with the parabolic surfaces  62  extending aft and with slots  80  adapted to coact with corresponding pins  82  in the after section of the fletchings as will be described in connection with  FIG. 12 . 
     It can be seen that the after section  64  slides into the forward section  60  in which pins  82  extend into slots  80  in the forward section such that the aft section is locked to the forward section. Here the aft section  64  is that into which light is injected causing fletching glow. 
     Referring now to  FIGS. 11 and 12 , the subject lighted fletchings may be adapted for use in cross bow bolts by providing a flat surface  90  adapted to be contacted by the cross bow string which then propels the bolt forward, with the lighting of the fletchings accomplished as described above. 
     In  FIGS. 5 ,  6 ,  11  and  12 , for crossbows, light from the internally carried LED module exits annulus  50  through orifices  46  in support structure  48  into the fletchings, with structural rigidity and strength being added when support structure  48  is utilized to stabilize the nock against fracture during crossbow firing. 
     In  FIGS. 11 and 12  the flat surface for the nock provides for secure firing of a bolt, while in  FIGS. 5 and 6  a different style, often called a capture style crossbow nock is used. However, this system of a supporting nock structure transmitting light to the fletchings may be used either for a crossbow bolt or a conventional bow. 
     Referring now to  FIG. 13 , what is shown in cross section is how pin  24  is contacted with a bow string  94  to push dome  36  in the direction of arrows  96  to close a switch between the LED underneath the dome and batteries  42 . Here it can be seen that when the whole assembly is moved in the direction of arrows  96  light through orifice  46  enters into fletchings  20  through orifice  46 . 
     As mentioned hereinbefore the fletchings themselves may be co-molded and made of a urethane which is transparent. If it is a two piece fletching, the opaque piece may be made of urethane, whereas the transparent piece is also made of urethane. Many suitable materials could be used for the leading vane portion such as vinyl, polyethylene, polyurethane or other materials that can be blended to be flexible. The trailing fletching material should be transparent or nearly so, so are more limited in material selection. Silicone blends, urethane blends, polycarbonate blends or acrylic blends would be the most likely candidate materials. 
     While the subject invention is described in terms of the use of urethane for the fletchings, it will be appreciated that any clear material for the fletchings is within the scope of the subject invention. Moreover, the fletchings can also be made out of synthetic feathers which also will light up with the introduction of light into the fletching. 
     While the present invention has been described in connection with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications or additions may be made to the described embodiment for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.