Abstract:
A peep sight for an archery bow. The peep sight can define a peep aperture bounded by a curvilinear bulge optionally constructed from magnesium or a magnesium alloy. The peep sight bulge can circumferentiate the peep aperture, and can form an apex about midway between a forward surface and a rearward surface of the peep sight. The peep sight can define a serving slot and two or more angled bowstring strand slots for receiving portions of the bowstring strands to mount the peep sight to a bowstring. The peep sight can be blue in color. A method is provided including: machining a magnesium, magnesium alloy and/or other material blank into a peep body; and removing a portion of a peep body to define a peep aperture bound by a curvilinear bulge. Optionally, a strand slot and/or a serving slot can be machined into a surface of the body.

Description:
[0001]     This application claims benefit of U.S. provisional patent application 60/727,626, filed Oct. 19, 2005, which is hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to archery sighting devices, and more particularly to a peep sight for an archery bow.  
         [0003]     Peep sights generally are used on archery bows to assist in aiming. A peep sight usually is mounted on the string of the bow at a predetermined distance above a nocking point on the bowstring. The peep sight is secured to the string by separating strands of the bowstring and securing the peep between those strands. The peep sight includes a peep aperture alignable with a line of sight of an archer when the archer aims at a target. Specifically, when the archer draws the bowstring, the archer aims at a target by viewing it through the peep aperture and by aligning the peep aperture and a front sight mounted on the bow with the target. In effect, the peep sight ensures that the archer consistently aims the bow, which thereby improves accuracy.  
         [0004]     Conventional peep sights are manufactured from aluminum or plastics. Both materials present issues with respect to energy imparted by the bowstring to which the peep sights are mounted. Specifically, because peep sights are mounted on the bowstring, the additional weight of an aluminum peep sight on the bowstring has a deleterious affect on kinetic energy of the string, and thus the energy and velocity imparted to an arrow shot from the bow. Theoretically, plastic peep sights are lighter than aluminum sights; however, plastic peep sights usually are the same weight as aluminum peeps due to the material added to the plastic peep to provide strength comparable to an aluminum peep. Accordingly, conventional aluminum and plastic peeps have weight issues that affect performance.  
         [0005]     Another issue with many peep sights is that the peep aperture construction can make it difficult to aim in low light conditions, such as that encountered when bow hunting at dusk or dawn. For example, most peep apertures of aluminum or plastic peeps are cylindrical bores. In low light conditions, the cylindrical bore impedes visual clarity and targeting visibility. One solution to this problem is presented in U.S. Pat. No. 6,981,329 to Strathman, wherein the peep aperture of a plastic or aluminum sight includes two opposing, intersecting frusto-conical recesses which are tapered equally at approximately 35° to 45° to equally deflect light and form an inside, defined edge of the peep sight aperture. Although the Stratham peep construction can sometimes provide improved target visibility, many times it can deflect too much light. This can sometimes make it difficult to focus through the peep sight, particularly in low light conditions.  
       SUMMARY OF THE INVENTION  
       [0006]     The aforementioned problems are overcome by a peep sight, optionally manufactured from magnesium or a magnesium alloy, that defines an hourglass-shaped peep aperture.  
         [0007]     In one embodiment, the peep sight includes a curvilinear bulge that defines the peep aperture. This bulge can circumferentiate the peep aperture, and thereby contribute to and/or form the hourglass-shaped peep aperture. Optionally, the bulge includes a constant or uniform radius. Further optionally, the curvilinear bulge includes an apex centered generally between a front surface and a rear surface of the peep sight.  
         [0008]     In another embodiment, the peep defines one or more bowstring strand slots which enable the longitudinal axis of the aperture to be aligned along a preferred axis of viewing for the archer.  
         [0009]     In a further embodiment, the peep sight includes a generally circular outer surface which defines a circumferential serving groove. This circumferential groove can intersect the one or more bowstring strand slots and provide a location for a serving to secure the peep on the bowstring.  
         [0010]     In yet another embodiment, the peep sight is substantially blue, at least on its exterior surface. Being of this color, the peep sight provides improved aiming ability in low light conditions.  
         [0011]     In yet a further embodiment, the present invention provides a method of manufacturing a peep sight. The method includes providing an optional magnesium or magnesium alloy blank; machining the blank to define a peep sight aperture bounded by a curvilinear bulge. Optionally, the curvilinear bulge circumferentiates the aperture and is of a uniform radius.  
         [0012]     The present invention provides a light, simple and efficient peep sight. The hourglass peep aperture facilitates rapid target acquisition and aiming, enhances contrast between the peep and the target, and is suitable for low light shooting conditions. When the peep is constructed from a magnesium or magnesium alloy, it provides a significant weight advantage over conventional aluminum and/or plastic peep sights. Specifically, the magnesium or magnesium alloy peep can provide at least a one-third reduction in weight over a conventional aluminum peep, but also can provide strength characteristics comparable to and/or better than aluminum. Furthermore, when implemented, the method of manufacturing the present peep sight can provide a precisely and consistently manufactured peep sight having extremely precise tolerances.  
         [0013]     These and other objects, advantages and features of the invention will be more readily understood and appreciated by reference to the detailed description of the invention and the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a side view of an archery peep sight in accordance with the present invention mounted on a conventional archery bow;  
         [0015]      FIG. 2  is an enlarged side view of the peep sight with the bowstring in a drawn position;  
         [0016]      FIG. 3  is a view of the peep sight from the shooter side of the peep sight;  
         [0017]      FIG. 4  is a side view of the peep sight;  
         [0018]      FIG. 5  is a cross-sectional view taken along line  5 - 5  in  FIG. 3 ; and  
         [0019]      FIG. 6  is a cross-sectional view of an alternative embodiment of the peep sight. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
     I. Construction  
       [0020]     A peep sight in accordance with a current embodiment is shown in  FIGS. 1-5  and generally designated  10 . With reference to  FIG. 1 , the peep sight  10  can be used on a compound archery bow  100 . Although described here in connection with a compound archery bow, it is to be understood that the peep sight can be used with a recurve bow, a long bow, or any other bow or projectile shooting device.  
         [0021]     The compound bow  100  shown in  FIG. 1  includes upper and lower limbs  105  and  107  joined with a riser  110 . The compound bow further includes a front sight  120 , a nocking point  123  and a bowstring  130 . The bow  100  is shown in full lines in a drawn state, and is shown in broken lines in an undrawn state.  
         [0022]     Referring to  FIGS. 2-5 , the peep sight  10  construction will now be described in more detail. The peep includes a body  12  having opposing surfaces—a front surface  14  and a rear surface  16 . Because the front surface  14  is on the target side relative to the archer, it is also referred to herein as a target surface. Because the rearward surface  16  is on the archer side, it is referred to herein as the shooter surface. These target and shooter surfaces  14  and  16  can be parallel to one another as desired.  
         [0023]     As shown in  FIGS. 3-5 , the body  12  generally forms a circular disc; however, the body can take other geometric forms depending on the application. The body  12  also defines a peep aperture  20  that passes completely through the body. The peep aperture  20  can include a longitudinal axis  22  that is substantially orthogonal to the target surface  14  and/or the shooter surface  16 . The aperture  20  is bounded by a curvilinear bulge  24 . This bulge  24  forms or at least contributes to an hourglass configuration of the aperture when a cross section of the body  12  ( FIG. 5 ) is considered. Where the curvilinear bulge circumferentiates the entire peep aperture, it can be referred to as a circumferential curvilinear bulge.  
         [0024]     The bulge  24  can be uniformly radiused around the entire circumference of the peep aperture. For example, as shown in  FIG. 5 , radius R 1  is equal to radius R 2  in the cross-sectional view shown there. Of course, the curvilinear bulge can be void of any true radius, for example, the bulge can be a parabolic shape that forms the circumferential boundary of the aperture. Further optionally, the bulge  24  can include an apex  26 . This apex  26  can be positioned about midway between the target surface  14  and the shooter surface  16 . As desired, however, this apex  26  can be closer to either surface. In effect, the apex, or area immediately adjacent the apex, usually forms the innermost, smallest boundary of the peep aperture when an archer peers through the aperture as shown in  FIGS. 2 and 3 . With the curvilinear bulge  24 , a slight misalignment of the peep relative to a vertical plane when the bowstring is in the drawn position will not cause a significant distortion in the viewing aperture, and therefore will not be detrimental to aiming.  
         [0025]     The body  12  can also include an outer surface  18  that surrounds the peep sight. This outer surface can be circumferential and can define a serving slot  40  around a substantial portion of the outer surface. The serving slot  40  can be of a uniform or varied depth and cross section. As shown, the cross section of the serving slot  40  is generally of a rectangular shape; however, square, rounded, elliptical or other geometric configurations can be used for the slot  40  as desired.  
         [0026]     The peep sight body  12  can further define bowstring strand slots  30 , which are designed to receive generally equal sized strand bunches from a multi-strand bowstring. The slots can be generally circular cross section; however, square, rounded, elliptical or other geometric configurations can be used for the slots  30  as desired. Where the slot cross section is circular so that it forms a cylindrical recess, the bottom of the recess can be common with the bottom of the serving slot  40 . Regardless of the shape of either of the slots  30  and  40 , these slots  30  and  40  can intersect one another.  
         [0027]     Generally, as shown in  FIGS. 2 and 3 , the slots  30  are positioned at an angle a relative to the longitudinal axis  22  so that when the bowstring is in its drawn state, and thus at an angle different from an undrawn state, the longitudinal axis  22  is generally aligned with the front sight  122  and/or a target along the archer&#39;s line of sight. Further, the slots  30  can be defined by the outer surface  18  of the body  12  at approximately mirrored locations. This can facilitate balancing the peep  10  between the strands of the bowstring and alignment.  
         [0028]     The peep sight  10  can be manufactured from a variety of materials. Preferably, it is manufactured from magnesium and/or magnesium alloy. Such a construction results in a weight reduction of a third over a similarly constructed aluminum peep. The peep of the present construction can be, however, constructed from other materials, such as aluminum, aluminum alloy or plastic, such as acrylic polyvinyl chloride, polypropylene, polyethylene and other polymers. When constructed from these other materials, the components may be cast, dipped, coated, extruded or injection molded. When constructed from magnesium or magnesium alloys or other metals such as aluminum, the peep can be manufactured using a Computer Numerical Control (CNC) machine, or any of the other manufacturing techniques mentioned above.  
         [0029]     The components of the peep sight  10  can be of a variety of sizes. The outer diameter of the body  12  can have a maximum width or diameter of about 3/16″ to about ⅝″. The peep sight aperture diameter, for example, the diameter at the apex  26  of the curvilinear bulge  24 , can vary in size from about 1/16″ to about ⅝″ depending on the application.  
         [0030]     Finally, the peep sight  10  optionally can be colored to enhance light gathering ability and to facilitate low light shooting conditions. For example, in the embodiment shown, the entire peep sight  10 , or merely the circumferential curvilinear bulge  24 , can be anodized or otherwise treated with a blue material, that is, a material that reflects substantially only light having a wavelength between about 475 nanometers and about 510 nanometers. As desired, the peep sight  10  and/or its components can alternatively be black, white or other colors depending on the shooting application.  
       II. Method of Manufacture  
       [0031]     The manufacture of the peep sight  10  will now be described. Generally, the peep sight  10  can be constructed from a magnesium, magnesium alloy or any other material. To begin manufacture, a material blank is positioned in a CNC machine. The machine performs a variety of operations, manipulating the blank to construct the peep  10 . In those operations, the CNC machine creates the curvilinear bulge  24 , forms the serving slot  40  and generates the string slots  30 . The machine can also remove any sharp edges around the target surface  14  and the shooter surface  16 , or elsewhere as desired. The machined peep optionally can be treated with a material to provide a blue color. Thereafter, the peep sight  10  is finished and readied for packaging.  
       III. Method of Mounting To An Archery Bow  
       [0032]     With reference to  FIGS. 1-2 , a method of mounting the peep sight to a bow will now be described. Specifically, the peep sight  10  is mounted to an archery bow by separating the strands of the bowstring into two approximately equal strand bunches, and sliding the peep between the two strand bunches so that the strands come to rest in the strand slots  30 . Preferably, the peep is inserted at a predetermined position along an archer&#39;s line of sight that is aligned when the bowstring is fully drawn as shown in full lines in  FIG. 1 . With the strands of the bowstring inserted in the slots  30 , an optional serving (shown in phantom in  FIG. 2 ) is wrapped around the serving slot  40  and tied to secure the peep sight  10  in the desired location on the bowstring. To prevent the peep sight  10  from misaligning with the archer&#39;s line of sight, a peep sight bowstring alignment tubing  129  ( FIG. 1 ) can be used as desired.  
       IV. Method of Use  
       [0033]     With reference to  FIG. 1 , the method of using the peep will now be described. As shown there, the bowstring is drawn from an undrawn state in broken lines to a drawn state in solid lines. Because the bowstring slots  30  are at an angle relative to the longitudinal axis  22  of the peep sight  10 , they compensate for the realignment of the bowstring at its drawn state angle. Accordingly, the peep is aligned vertically, and with the archer&#39;s line of sight. Therefore, the archer can further align a forward sight pin  122  with the axis  22  of the peep, or some other desired alignment axis.  
         [0034]     Because of the curvilinear bulge  24  and general construction of the peep, the peep provides improved contrast with a sight or target sighted through the peep aperture  20 . The quality of the image is improved in low light conditions as the peep is able to gather more light. Further, when colored blue, the peep is comfortable and easy to view due to its similarity to the color of the sky. With the peep sight  10 , an archer can aim consistently and easily, and accordingly, can achieve improved arrow groupings and overall accuracy.  
       V. Alternative Embodiment  
       [0035]     In an alternative embodiment, the curvilinear bulge  24  of the peep sight  10  can be modified. Specifically, with reference to  FIG. 7 , the peep sight  210  includes a curvilinear bulge  224  wherein the radius of the bulge, that is, R 3  and R 4 , which are of equal length (but optionally can be modified to be of varying length) are moved forward of the center in the direction of the arrows. Accordingly, the apex  226  is closer to the target face  214  than it is to the shooter face  216 . The radius R 3  and R 4  can be moved forward and/or rearward depending on the application. For example, in another embodiment, the apex  226  can be closer to the shooter surface  216  than to the target surface  214 .  
         [0036]     Further alternatively, the bulge  224  can include compound radii. For example, the bulge  224  can be formed from multiple intersecting arcs of circles having different radii (not shown). Additionally, although shown as a portion of an arc of a circle, the bulge can be configured in the shape of a portion of an ellipse, a parabola, or any other geometric, curvilinear configuration. As used herein, when the bulge is constructed in such a curvilinear configuration, it is considered a “curvilinear bulge”.  
         [0037]     The above descriptions are those of the preferred embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. Any references to claim elements in the singular, for example, using the articles “a,” “an,” “the,” or “said,” is not to be construed as limiting the element to the singular.