Abstract:
Rotation of the cylindrical handle rotates the geared sprocket which biases the linear slide member, which selectively raises and lowers the cylindrical bow sight housing. A locking knob releasably secures the cylindrical handle during rough handling. The cylindrical bow sight includes a circular ring on the front face of the circular bow sight housing, and a bubble level provides a level indication. A fiber optic sight is centered in the bow sight housing in optical communication with a fiber optic band to improve the visibility of the bow sight in low light conditions. A sliding keyway and adjustment screw adjusts the cylindrical bow sight elevation. Indicia on the cylindrical handle provides alignment data responsive to the position of the cylindrical bow sight in relation to the distance to a remote target.

Description:
CROSS REFERENCE TO RELATED TOPICS 
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   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
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   REFERENCE TO SEQUENCE LISTING A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX 
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   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a geared bow sight for archery, and more particularly to a geared linearly adjustable archery bow sight. 
   2. Background of the Invention 
   Vertically adjustable bow sights are known to adjust for trajectory of the arrow in response to the distance to the target. Some of these devices utilize a trial and error adjustment means, which are tested and adjusted by the user in response to actual field use. The bow sights typically utilize scale or distance marks to estimate the distance adjustment required to reach the target. Distance adjustments vary by the bow type, the draw strength, the target elevation, the target distance, wind conditions, terreign elevation, etc. 
   U.S. Pat. No. 5,975,069 issuing to Harold M. Hamm et al. on Nov. 2, 1999, discloses an archery bow sight apparatus, which has a fiber optic bow sight mounted in an elongated housing, and is adjustably positioned by manually moving a cam member to raise or lower the bow sight in response to the distance of the user from the target. The bow sight housing is not adjustable to accommodate various bow thickness configurations; and gears are not used to precisely position and maintain the cam member in position during use. A large block of light absorbing material is used to intensify the light received by the fiber optic bow sight. 
   U.S. Pat. No. 5,092,052 issuing to Samuel Godsey on Mar. 3, 1992 utilizes a linear track on the mounting plate and a complimentary linear track on the rear edge of the sight plate. A slot is required in the sight plate to compensate for the arcuate movement of the adjustable arm. The linear track is subject to jamming in the presence of particles and debris that become lodged in the track. 
   U.S. Pat. Nos. 4,109,179; 4,418,479; 4,497,116 and 4,541,179 each utilize a form of quadrilateral linkage to obtain linear movement of the bow sight. 
   Other U.S. patents relating to adjustable bow sights include, for example, U.S. Pat. Nos. 2,642,661; 2,667,692; 3,318,298; 4,473,959; 4,567,668; 4,977,677; and 4,986,001. 
   Thus, what is needed is a geared archery bowsite, which is linearly responsive to adjustment by the user, by rotating a cylindrical handle portion, with a locking knob positioned adjacent to the cylindrical handle portion to reliably secure the elevated position of the bowsite in relation to the bow. The cylindrical handle portion further has indicia about its outer periphery for identifying the distance from the bowsite to the target. The geared archery bowsite is rugged in contruction, yet simple in operation, is viewable in a variety of light conditions, is compact in design, light weight, and does not interfere with the operation of the bow or its user during normal hunting or target conditions. 
   The above mentioned and other features and objects of the invention, and the manner of attaining them will be best understood by reference to the following description of an embodiment of the invention, when considered in conjunction with the accompanying drawing: 
   BRIEF SUMMARY OF THE INVENTION 
   Accordingly, it is an object of the present invention to provide a geared archery bow sight apparatus, that addresses these needs. 
   It is another object of the present invention to provide a rotatable cylindrical handle portion for ease of linearly adjusting the elevation of the bow sight apparatus to correspond to the distance to a target. 
   It is still another object of the present invention to provide a locking knob to releasably secure the geared cylindrical handle portion in place during use and while traversing difficult terreign. 
   It is yet another object of the present invention to provide a circular sighting ring on the front face of the fiber optic bow site to improve visual alignment of fiber optic sight in relation to the target, in varying light conditions. 
   It is still another object of the present invention to provide a fiber optic light gathering ring extending about the outer periphery of the cylindrical bow sight housing, wherein the light gathering ring is in optical communication with the fiber optic bow sight centered within the cylindrical bow sight housing. 
   It is a further object of the present invention to adjustably position the bow sight mounting bracket to the cylindrical bow sight housing to accommodate various bow sizes and styles. 
   It is also an object of the present invention to provide two spaced linear grooves in the linear slide member, with first and second guide bushings slidably received in the first linear groove, and a third guide bushing slidably received in the second linear groove, to improve precise linear adjustment of the bow site in relation to movement of the cylindrical handle. 
   It is still another object of the present invention to provide a fourth guide bushing slidably received in a transverse slot located in the linear slide member, and to precisely position the fourth guide bushing to eliminate play between the linear slide member and the articulated cam member. 
   It is yet another object of the present invention to provide indicia on the outer periphery of the cylindrical handle to identify the elevation of the bow sight mounting bracket in relation to the distance to a target. 
   The above mentioned and other features and objects of the invention, and the manner of attaining them will be best understood by reference to the following description of an embodiment of the invention, when considered in conjunction with the accompanying drawings: 

   
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a perspective view of the assembled geared archery bow sight apparatus with the articulated cam member positioned on-center, prior to installing the geared archery bow sight apparatus on a bow. 
       FIG. 2  is a detailed view of the mounting frame member. 
       FIG. 3  is a detailed view of the linear slide member. 
       FIG. 4  is a detailed view of the articulated cam member. 
       FIG. 5A  is a partial side view of the cylindrical bow sight housing showing the sliding keyway and screw used to adjust the position of the cylindrical bow housing in relation to the mounting frame member. 
       FIG. 5B  is a cross sectional view of the keyway taken along lines  5 B- 5 B in  FIG. 5A . 
       FIG. 6  is a bottom assembly view of the bow sight apparatus with the articulated cam member positioned off-center, as shown from the opposite side of  FIG. 1 . 
       FIG. 7  is a side view of the assembled geared archery bow sight apparatus shown in  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The geared archery bow sight apparatus  10 , as shown in  FIG. 1  through  FIG. 7 , shows the geared archery bow sight apparatus  10  of the present invention. As shown in  FIG. 2 , the mounting frame member  20  has a first linear slot  22 , with a second linear slot  24  in spaced parallel alignment with the first linear slot  22 . One or more lightening holes  38  extend through the mounting frame member to reduce the weight of the geared archery bow sight apparatus  10 . A convex gear member  26  with a plurality of fixed teeth  28  is secured in a gear aperture  32  provided in the mounting frame member  20 . The convex gear member  26  is preferably secured to the mounting frame member  20  with a suitable screw  30 , or other known fastening means. A rotatable gear sprocket  66  engages the fixed teeth of a convex gear member  26 , as disclosed in further detail herein. 
   As shown in  FIG. 1 , the linear slide member  40 , is adjustably positioned in relation to the mounting frame member  20  by a first and a second slidable guide bushings  42 ,  44  sized to be slidably received within the first linear slot  22 . A third slidable guide bushing  46  is sized to be slidably received within the second linear slot  24 . The third guide bushing  46  is preferably slightly offset from center, providing a cam action to precisely position the third guide bushing  46  in the second linear slot  24 , eliminating tolerance concerns. The guide bushings  42 ,  44 ,  46  are preferably made of a low friction material, such as teflon, nylon, or other suitable plastic material. Any low friction material known in the art may be used, without departing from the scope of this disclosure, or the accompanying claims. The guide bushings  42 ,  44 ,  46  are each secured to the linear slide member  40  with a fastening means  48 , such as with a suitable screw and nut. 
   As shown in  FIG. 3 , the linear slide member  40  has a plurality of spaced apertures  50  positioned to adjustably receive suitable fasteners  52  to secure the optical mounting bracket  54  to the linear slide member  40 . The plurality of spaced apertures  50  provide a macro adjustment for locating the cylindrical bow sight housing  90  to the linear slide member  40  in one of several locations. A transverse slot  56  is positioned in the linear slide member  40  between the first and second slidable guide bushings  42 ,  44 . The transverse slot  56  is sized to receive a fourth guide bushing  58  therein. The fourth guide bushing  58  is secured in proximity to the second end  59  of the articulated cam member  60 , and extends at assembly into the transverse slot  56 . 
   The fourth guide bushing  58  is secured near the distal end  59  of the articulated cam member  60 , as shown in  FIG. 4 . The central portion of the articulated cam member  60  is pivotally secured by a suitable fastening means  62  to a suitable cam aperture  64  located in the mounting frame member  20 . The articulated cam member  60  also has a rotatable geared sprocket  66  which is positioned to engage the fixed teeth  28  on the convex gear member  26  within the enlarged aperture  32  provided in the mounting frame member  20 . A fastener  68  extends through the rotatable geared sprocket  66 , and through the articulated cam member  60  to engage a rotatable cylindrical handle  70 . When the cylindrical handle  70  is rotated, the geared sprocket  66  also rotates, moving the articulated cam member  60 , which in turn moves the linear slide member  40 , to adjustably position the optical mounting bracket  54 . The geared sprocket  66  maintains the adjusted position of the linear slide member  40 , and assures precise alignment during use. 
     FIG. 5A  is a partial side view of the cylindrical bow sight housing  90 , showing the cylindrical bow sight housing  90  mounted to a sliding keyway  82  which engages a complimentary keyway  84  secured to selected apertures  50  on the optical mounting bracket  54 . An adjustment screw  86  is threaded through the optical mounting bracket  54  to bias the position of the cylindrical bow sight housing  90  in relation to the optical mounting bracket  54 . This adjustment allows the user to adjust the position of the cylindrical bow sight housing  90  in relation to the mounting frame member  20 , to accommodate different bow sizes and styles (not shown). 
     FIG. 5B  is a cross sectional view of the sliding keyway  82  and the complimentary keyway  84  taken along lines  5 B- 5 B in  FIG. 5A . As the complimentary keyway  84  is biased by the adjustment screw  86 , the complimentary keyway  84  slidably engages the sliding keyway  82  to adjustably position the cylindrical bow site housing  90  in relation to the optical mounting bracket  54 . 
   A cylindrical handle  70  is best shown in  FIG. 6 , where the cylindrical handle  70  has been rotated to bias the articulated cam member  60 , which moves the linear slide member  40  to adjust the height of the cylindrical bow sight housing  90 . The cylindrical handle  70  includes an arcuate aperture  78  positioned to allow movement of the cylindrical handle  70  in relation to a locking knob  80  extending through the arcuate aperture  78 . The locking knob  80  is preferably knurled  72  about a portion of the outer periphery, for ease of rotating the cylindrical handle  70 . Markings, or other indicia  74  are preferably placed about a portion of the outer periphery of the cylindrical handle  70  to indicate a distance to a target (not shown). The tip  61  of the articulated cam member  60  preferably includes a pin  76  extending in spaced relation adjacent to a portion of the cylindrical handle  70  in close proximity to the indicia  74 , to indicate the distance to a target. 
   In a preferred embodiment, a printed strip  75  with markings or other indicia  74  thereon is positioned upon the outer circumference of the cylindrical handle  70 , and the user test fires an arrow at a target positioned 20 feet from the bow. A second target it then positioned at 60 feet from the bow, and a second arrow is fired. The markings on the printed strip are then compared with the position of the pin  76  in relation to the markings  74 , and the difference in the markings is used to determine the spacing required for each of the marks or indicia  74 . A second printed strip  75  with suitable spacing is then used, to accurately determine the elevation required to reach a target at a given distance. 
   A locking knob  80  extends through an arcuate aperture  78  in the cylindrical handle  70 , and through the articulated cam member  60 , to engage the arcuate recess  34  provided in the mounting frame member  20 . The arcuate recess  34  preferably has a step  36  provided to engage the distal end  82  of the locking knob  80 . When tightened, the cylindrical handle  70  cannot be easily moved, even during rough handling in the field. When the locking knob  80  is loosened, the cylindrical handle  70  is free to rotate, which adjustably positions the cylindrical bow sight housing  90  to the desired distance from the target. 
   The optical mounting bracket  54  extends beyond the linear slide member  40  to engage a sliding keyway  82  with a complimentary keyway  84  extending from the cylindrical bow sight housing  90 , as best shown in  FIG. 5A  and  FIG. 5B . A threaded screw  86  is rotatably mounted to the sliding keyway  82 , and threadably engages the optical mounting bracket  54  to adjustably position the cylindrical bow sight housing  90  to suit various sizes and shapes of bows (not shown). 
   The cylindrical bow sight housing  90  includes a circular ring of paint  92  mounted about the circular front face  88  of the cylindrical bow sight housing  90 , to center the fiber optic bow sight  100  in relation to the circular ring of paint  92 , for ease of sighting a target in low light conditions. The cylindrical bow sight housing  90  also includes a fiber optic material  94  extending about the outer periphery of the cylindrical bow sight housing  90 . The fiber optic material  94  is in optical communication with the fiber optic bow sight  100 , centered in the circular bow site housing  90 . The fiber optic sight  100  provides improved visibility in low light conditions, to aid the user in framing the target within the cylindrical bow sight housing  90 . A bubble level  98  is also mounted within the cylindrical bow sight housing  90  to aid the user in aligning the bow with the target. 
   In operation, the geared archery bow sight apparatus  10  is mounted to a user&#39;s bow (not shown) in proximity to the bow handle using the mounting apertures  36  provided in the mounting frame member  20 , in a position which will not interfere with the normal operation of the bow during the shooting of a suitable arrow (not shown). Suitable fasteners (not shown) extend through the mounting apertures  36  for ease of mounting the geared archery bow sight apparatus  10  to the user&#39;s bow. 
   Once the geared archery bow sight apparatus  10  has been mounted to the user&#39;s bow, the user rotates the cylindrical handle  70 , which rotates the geared sprocket  66 , which acts against the fixed gear teeth  28 , to bias the articulated cam member  60 , which moves the linear slide member  40  to selectively raise or lower the cylindrical bow sight housing  90 . Marking indicia  74  on the cylindrical handle  70  may be used to align with the pin  76 , to select the preferred distance to the target, ensuring repetitive results. 
   The arcuate aperture  78  extending through the cylindrical handle  70  provides rotation of the cylindrical handle  70  in relation to the locking knob  80 , as the optical mounting bracket  54  is raised or lowered by rotation of the cylindrical handle  70 . The locking knob  80  extends through the arcuate aperture  78  in the cylindrical handle  70 , and through the linear slide member  40 , and is slidably received in the arcuate recess  34  located in the mounting frame member  20 . When the locking knob  80  is tightened by rotation of the locking knob  80 , the cylindrical handle  70  and linear slide member  40  are secured to the mounting frame member  20 , ensuring a fixed position of the circular bow sight housing  90  during rough handling. 
   When the locking knob  80  is loosened by rotation of the locking knob  80 , the cylindrical handle  70  is free to rotate, which biases the articulated cam member  60 , which acts through the geared sprocket  66  and the convex fixed gear member  26  to bias the linear slide member  40  in relation to the mounting frame member  20 , to selectively raise or lower the optical mounting bracket  54 . 
   Thus, while a preferred embodiment of the geared archery bow sight apparatus  10  has been disclosed, one of average skill in this art may make numerous changes and modifications without departing from the scope of this invention, and such changes or modifications are intended to fall within the scope of the following claims.