Patent Publication Number: US-7900365-B1

Title: Archery sight assembly

Description:
BACKGROUND 
     The field of the present invention relates to archery sights. In particular, an archery sight assembly is disclosed herein that includes a linear bearing, an adjustable pointer, or a rack coupled by one or more gears to an adjustment knob. 
     A wide variety of archery sights have been developed previously. Ideally, in most archery sights a pin, reticle, cross-hair, or other reference marker is positioned relative to the bow so that when lined up on a target object at a given distance (i.e., when the archer holding the drawn bow looks through the sight with the reference marker on the target object), an arrow shot by the bow will hit the target object. To achieve that goal requires precise adjustment of the position and orientation of the sight with respect to the bow. In addition, to accurately aim at objects at other distances or to account for crosswinds requires known, repeatable adjustments of the sight. To that end, a typical archery sight includes an adjustable positioning mechanism coupling the sight to the bow, and the positioning mechanism often includes some sort of scale for indicating the position of the sight (equivalently, the target position that results from aiming with the sight). 
     SUMMARY 
     An archery sight assembly comprises an archery sight, a mounting bracket, and a positioning mechanism. The archery sight defines a longitudinal sighting direction. The mounting bracket is arranged to be substantially rigidly attached to an archery bow. The positioning mechanism couples the archery sight to the mounting bracket and is arranged to provide adjustment of the position or orientation of the archery sight relative to the mounting bracket. The archery sight assembly can be mounted on an archery bow by substantially rigidly attaching the mounting bracket to the bow. 
     In one embodiment of an archery sight assembly, the positioning mechanism includes at least one linear bearing for providing substantially linear motion of the archery sight along a corresponding direction substantially transverse to the sighting direction. The linear bearing comprises a bearing track, a bearing slide, and a pair of cylindrical bearing members. The bearing track has along at least a portion of its length a U-shaped cross-section transverse to a direction of motion defined by the linear bearing. Each of two side portions of the U-shaped cross section of the bearing track has a corresponding groove on its inner surface arranged substantially parallel to the defined direction of motion. The grooves of the corresponding side portions face one another across the bearing track. The bearing slide is positioned between the side portions of the bearing track and reciprocally moveable within the bearing track along the defined direction of motion. The bearing slide has a groove on each of two opposite sides, each arranged substantially parallel to the defined direction of motion and facing a corresponding one of the bearing track grooves. Each cylindrical bearing member is positioned with its corresponding cylinder axis substantially parallel to the defined direction of motion and is engaged with corresponding facing bearing track and bearing slide grooves. Each cylindrical bearing is arranged to slide along at least one of the corresponding engaged grooves as the bearing slide moves along the defined direction within the bearing track. 
     In another embodiment of an archery sight assembly, the positioning mechanism includes (i) a scale arranged to indicate motion along or about a corresponding direction or axis of motion and (ii) a pointer arranged so that the scale moves relative to the pointer during the indicated motion. The pointer includes an adjustment mechanism that enables it to be repositioned relative to the scale and a locking mechanism that enables it to be released and repositioned by the adjustment mechanism and to be retained at a desired position relative to the scale. 
     In another embodiment of an archery sight assembly, the positioning mechanism comprises a rack, an adjustment knob, and one or more gears coupling the rack to the adjustment knob. The rack provides substantially linear motion of the archery sight along a corresponding direction substantially transverse to the sighting direction. 
     A method for making the archery sight assembly comprises coupling the archery sight to the mounting bracket using the positioning mechanism. A method for using the archery sight assembly comprises adjusting the position or orientation of the archery sight relative to the mounting bracket using the positioning mechanism. 
     Objects and advantages pertaining to archery sights may become apparent upon referring to the exemplary embodiments illustrated in the drawings and disclosed in the following written description or appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front right perspective view of an exemplary archery sight assembly. 
         FIG. 2  is a front left perspective view of the exemplary archery sight assembly. 
         FIG. 3  is a rear left perspective view of the exemplary archery sight assembly. 
         FIG. 4  is a rear right perspective view of the exemplary archery sight assembly. 
         FIG. 5  is an enlarged right perspective view of a portion of the exemplary archery sight assembly. 
         FIG. 6  is a left side view of the exemplary archery sight assembly. 
         FIG. 7  is a right side view of the exemplary archery sight assembly mounted on a bow. 
         FIG. 8  is an enlarged right side view of a portion of the exemplary archery sight assembly. 
         FIG. 9  is a top view of the exemplary archery sight assembly mounted on a bow. 
         FIG. 10  is an enlarged top view of a portion of the exemplary archery sight assembly. 
         FIGS. 11A-11C  are cross-sectional views of a bearing slide, a bearing track, and an assembled linear bearing of the exemplary archery sight assembly. 
         FIG. 12  is a left side view of a knob, gear, and rack of the exemplary archery sight assembly. 
         FIG. 13  is a left side view of a knob, gear set, and rack of another exemplary archery sight assembly mounted on a bow. 
     
    
    
     The embodiments shown in the Figures are exemplary, and should not be construed as limiting the scope of the present disclosure or appended claims. 
     DETAILED DESCRIPTION OF EMBODIMENTS 
     An archery sight assembly  10  comprises an archery sight  12 , a mounting bracket  14 , and a positioning mechanism  20  ( FIGS. 1-10 ). The archery sight  12  defines a longitudinal sighting direction  13  (z-axis in  FIGS. 1-10 ). The mounting bracket  14  is arranged to be substantially rigidly attached to an archery bow  99  (shown in  FIGS. 7 and 9 ), thereby mounting the archery sight  12  on the bow  99 . The positioning mechanism  20  couples the archery sight  12  to the mounting bracket  14  and is arranged to provide adjustment of the position or orientation of the archery sight  12  relative to the mounting bracket  14 . The positioning mechanism  20  can include any desired components arranged in any suitable way to provide the desired adjustments of the position or orientation of archery sight  12 . Some archery sights can provide adjustment along all six degrees of freedom, i.e., linear motion along three translational directions and rotary motion about three rotation axes; other archery sights might only provide a subset of those motions. Most archery sights provide linear motion along two directions substantially transverse to the sighting direction (i.e., along the x- and y-axes in the Figures). In the example shown in  FIGS. 1-10 , loosening a locking screw with knob  16  enables adjustment parallel to the z-axis by sliding a support member through mounting bracket  14 , and the assembly  10  is arranged to provide adjustment parallel to the x-axis using knob  18  and parallel to the y-axis (i.e., along direction  15 ) using cylindrical member  22  (coarse) or knob  24  (fine). Adjustment along a substantially vertical direction (when the bow is held in a drawn position ready to shoot) can be used to correct for range, and adjustment along a horizontal direction can be used to correct for windage. Those directions can differ in their orientations relative to the bow  99  on which the archery sight  12  is mounted. For a regular bow (as shown in the Figures), the vertical adjustment typically is substantially parallel to the riser of the bow  99  along direction  15 . For a crossbow, the vertical adjustment typically is substantially perpendicular to the riser of the bow. 
     A method for making the archery sight assembly  10  comprises coupling the archery sight  12  to the mounting bracket  14  using the positioning mechanism  20 , and can further comprise substantially rigidly attaching the mounting bracket  14  to the archery bow  99 . A method for using the archery sight assembly  10  comprises adjusting the position or orientation of the archery sight  10  relative to the mounting bracket  14  using the positioning mechanism  20 , and can further comprise substantially rigidly attaching the mounting bracket  14  to the archery bow  99 . 
     In some embodiments of the archery sight assembly  10 , the positioning mechanism  20  includes at least one linear bearing  100  for providing substantially linear motion of the archery sight  12  along a corresponding direction  15  substantially transverse to the sighting direction  13 . The linear bearing  100  comprises a bearing track  120 , a bearing slide  140 , and a pair of cylindrical bearing members  160   a / 160   b . The bearing track  102  has along at least a portion of its length a U-shaped cross-section ( FIG. 11B ) transverse to the direction of motion  15  that it defines. In the exemplary assembly  10 , the U-shaped cross-section includes a slot  126  for accommodating a rack  302  formed on the bearing slide  140  (described further below), and is interrupted by a gap (not shown) through which a gear  304  extends to engage the rack  304 . Other arrangements can be employed, including ones that do not include slot  126  in the bearing track  120  or rack  302  on the bearing slide  140 . Each of two side portions  122   a / 122   b  of the U-shaped cross section of the bearing track  120  has a corresponding groove  124   a / 124   b  on its inner surface arranged substantially parallel to the defined direction of motion  15 . The grooves  124   a / 124   b  face one another across the bearing track  120 . 
     The bearing slide  140  ( FIG. 11A ) is positioned between the side portions  122   a / 122   b  of the bearing track  120  ( FIG. 11C ) and is reciprocally moveable within the bearing track along the defined direction of motion  15  (along the y-axis in the Figures). The bearing slide  140  has a groove  144   a / 144   b  on each of two opposite sides, with each groove  144   a / 144   b  arranged substantially parallel to the defined direction of motion  15  and facing a corresponding one of the grooves  124   a / 124   b . The cylindrical bearing members  160   a / 160   b  are positioned with their corresponding cylinder axes substantially parallel to the defined direction of motion  15 . Each cylindrical bearing member  160   a / 160   b  is engaged with corresponding facing bearing track grooves  124   a / 124   b  and bearing slide grooves  144   a / 144   b , i.e., cylindrical bearing  160   a  is engaged with facing grooves  124   a  and  144   a , and cylindrical bearing  160   b  is engaged with facing grooves  124   b  and  144   b . Generally, each cylindrical bearing  160   a / 160   b  can be arranged to slide along one or both of the corresponding engaged grooves  124   a / 124   b / 144   a / 144   b  as the bearing slide  140  moves along the defined direction within the bearing track  120 . 
     In one example, the linear bearing  100  can be arranged so that each cylindrical bearing  160   a / 160   b  can move along both of its corresponding engaged grooves  124   a / 124   b / 144   a / 144   b , i.e., cylindrical bearing  160   a  can slide along both of the grooves  124   a  and  144   a  and cylindrical bearing  160   b  can slide along both of the grooves  124   b  and  144   b . The range of motion of each cylindrical bearing member  160   a / 160   b  need not be the same along both of its corresponding engaged grooves  124   a / 124   b / 144   a / 144   b . Alternatively, each cylindrical bearing  160   a / 160   b  can be constrained to slide along only one of the corresponding engaged grooves, i.e., cylindrical bearing  160   a  can slide along only one of the grooves  124   a  or  144   a  and cylindrical bearing  160   b  can slide along only one of the grooves  124   b  or  144   b.    
     In the exemplary assembly  10 , the bearing track grooves  124   a / 124   b  are arranged to receive the corresponding cylindrical bearing members  160   a / 160   b  in a snap-fit or press-fit arrangement, and the bearing track grooves  144   a / 144   b  are arranged as v-grooves. The cylindrical bearing members  160   a / 160   b  are therefore constrained to slide only along v-grooves  144   a / 144   b . Other arrangements or groove types can be employed 
     In the exemplary assembly  10  the bearing slide  140  is shown as being longer than bearing track  120  so that end portions of the bearing slide  140  extend beyond the ends of bearing track  120 . In alternative arrangements (not shown) the bearing track  120  and the bearing slide  140  can be substantially equal in length, or bearing track  120  can be longer than bearing slide  140 . 
     The bearing track  120  can be arranged to apply an adjustable level of compression to the cylindrical bearing members  160   a / 160   b  between the corresponding engaged grooves  124   a / 124   b / 144   a / 144   b . In the example shown, the linear bearing  100  includes one or more adjustment screws  110  that are arranged to urge the side portions  122   a / 122   b  toward one another, compressing the cylindrical bearings  160   a / 160   b  against the grooves  144   a / 144   b  of the bearing slide  140 . Such adjustment can be employed to ensure that the linear bearing  100  enables motion along the defined direction  15  but does not enable an unacceptable degree of motion along or about other directions or axes. For example, excessive compression can prevent the desired motion along the defined direction, or can cause that motion to require too much force to be applied (i.e., to be too “stiff”). Such stiffness would be perceived or assessed differently by different users. Alternatively, insufficient compression of the cylindrical bearing members  160   a / 160   b  can allow an unacceptable range of translational motion of the bearing slide  140  in directions transverse to the defined direction  15  (i.e., along the x- or z-axis in the Figures), or can allow the bearing track  140  to pitch, roll, or yaw. Such insufficient compression can arise over time due to wear of the cylindrical bearing members  160   a / 160  or the grooves  124   a / 124   b / 144   a / 144   b . Adjustment of the level of compression of the cylindrical bearing members  160   a / 160   b  between the facing grooves  124   a / 124   b / 144   a / 144   b  enables a user to set a desired level of “stiffness” to the motion along the defined direction  15 , or to readjust the compression to compensate for later wear. 
     The bearing track  120  or bearing slide  140  can be arranged or adapted in any suitable way to provide the adjustable compression of the cylindrical bearing members  160   a / 160   b . In one example, the side portions  122   a / 122   b  of the bearing track  120  can be sufficiently deformable (plastic or elastic) so as to permit the adjustment screws  110  (or other suitable adjustment actuator;  FIGS. 3 and 6 ) to move the side portions  122   a / 122   b  of the bearing track  120  toward one another. In another example (shown in  FIGS. 1-10 ), the bearing track  120  can comprise discrete longitudinal portions  120   a / 120   b  ( FIG. 10 ), each including a corresponding one of the side portions  122   a / 122   b . The adjustment screws  110  (or other suitable adjustment actuator) are arranged to urge the bearing track longitudinal portions  120   a / 120   b  (along with the side portions  122   a / 122   b ) toward one another. Methods for making or using the archery sight assembly  10  can include adjusting the compression of the cylindrical bearing members  160   a / 160   b  between the facing grooves  124   a / 124   b / 144   a / 144   b.    
     The bearing track  120 , the bearing slide  140 , and the cylindrical bearing members  160   a / 160   b  can be made of any suitable material or combination of materials. In one example, bearing track  120  and bearing slide  140  are made of aluminum and the cylindrical bearing members  160   a / 160   b  are made of stainless steel. Any other suitable metal, alloy, or polymer materials, friction materials, or combinations thereof, can be employed as needed or desired. 
     In other embodiments of the archery sight assembly  10 , the positioning mechanism  20  includes (i) a scale  21  arranged to indicate motion along or about a corresponding direction or axis of motion and (ii) a pointer  200  arranged so that the scale  21  moves relative to the pointer  200  during the indicated motion. The pointer  200  includes an adjustment mechanism that enables it to be repositioned relative to the scale  21 , and includes a locking mechanism that enables it to be released and repositioned by the adjustment mechanism and to be retained at a desired position relative to the scale  21 . 
     In the exemplary assembly  10 , the indicated motion is linear motion along the direction  15  (along the y-axis in the Figures), and the positioning mechanism  20  includes a cylindrical member  22  arranged to rotate about its axis in synchrony with the indicated linear motion along direction  15 . The scale  21  is disposed around an outer circumference of the cylindrical member  22 . Scale  21  can be arranged in any other suitable way on the positioning mechanism  20 , e.g., a linear scale and pointer can be positioned on linear bearing  100 . In the exemplary assembly  10  the pointer  200  is coupled to the positioning mechanism  20  so that the adjustment mechanism moves the pointer along an arc-shaped path substantially concentric with the cylindrical member  22 . A portion  202   b  of the pointer is curved in the form of an arc that is substantially concentric with the cylindrical member  22 . 
     In the exemplary assembly  10 , the pointer  200  comprises a wire  202 , a threaded block  212 , an adjustment screw  214 , and a locking screw  232 . The wire  202  is bent to form (i) a first wire segment  202   a  substantially parallel to an axis of the cylindrical member  22  and positioned at its outer circumference over the scale  21 , and (ii) a pair of parallel, spaced-apart wire segments  202   b  curved in the form of an arc that is substantially concentric with the cylindrical member  22 . The threaded block  212  is mounted on or between the pair of wire segments  202   b . The adjustment screw  214  is threadedly engaged with the threaded block  212  and rotatably engaged with the positioning mechanism  20  so that turning the adjustment screw  214  moves the wire  202  along an arc-shaped path defined by the pair of curved wire segments  202   b . The adjustment mechanism in this example therefore comprises the threaded block  212  and the adjustment screw  214 . Any other suitable adjustment mechanism can be employed. The locking screw  232  passes between the pair of curved wire segments  202   b  and is threadedly engaged with the positioning mechanism  20  so that tightening the locking screw  232  locks the pair of curved wire segments  202   b  against the positioning mechanism  20 . The locking mechanism therefore comprises locking screw  232 . Any other suitable locking mechanism can be employed. 
     In the exemplary assembly  10 , the cylindrical member  22  is substantially rigidly connected to a substantially coaxial gear  304  and the gear  304  is arranged to couple motion of an adjustment knob to the indicated motion  15  of the positioning mechanism  20  by engaging rack  302  on bearing slide  140 . In this example (shown in  FIG. 12 ), a fine-adjustment knob  24  can be arranged to rotate cylindrical member  22  and gear  304  (in this example employing a worm drive  26 ), which in turn drives rack  302 . Alternatively, cylindrical member  22  can act as the knob when the fine-adjustment knob  24  is disengaged from cylindrical member  22  and gear  304  (e.g., by disengaging the worm drive  26 ). 
     Methods for making or using the archery sight assembly  10  can include disengaging the locking mechanism to release the pointer  200 , repositioning the pointer  200  with the adjustment mechanism to a desired position relative to the scale  21 , and engaging the locking mechanism to retain the pointer  200  at the desired position. Such methods can be employed, for example, when the bow  99  and the archery sight  12  have been aligned so that a known distance corresponds to a reference marker in the sight  12  (e.g., pin  11 , cross-hairs, or a reticle). The pointer  200  can then be repositioned so that a chosen mark on the scale  21  corresponds to the known distance (making future adjustment of the sight  12  to that distance more accurately repeatable), or so that a different distance can be selected by adjusting the position of sight  12  to match a different selected mark on scale  21 . 
     In other embodiments of the archery sight assembly  10 , the positioning mechanism comprises a rack  302  (formed on the bearing slide  140  in the exemplary assembly  10 ), an adjustment knob, and one or more gears that couple the rack  302  to the adjustment knob. In the example of  FIGS. 1-10  and  12 , with the fine-adjustment knob  24  disengaged, cylindrical member  22  acts as the adjustment knob, and the coaxial gear  304  couples the cylindrical member  22  to the rack  304  (through a gap in the bearing track  120 ; not shown). With fine-adjustment knob  24  engaged with the cylindrical member  22  (by means of worm drive  26  shown in  FIG. 12 ), knob  24  acts as the adjustment knob that is coupled to rack  302  by the worm drive  26  and gear  304 . 
     In the exemplary embodiment of  FIG. 13 , one or more additional gears  310  couple coaxial gear  304  to rack  302 . As in the previous example, a fine-adjustment knob  24  or cylindrical member  22  can act as the adjustment knob, depending on whether fine-adjustment knob  24  is engaged to rotate cylindrical member  22 . With either adjustment knob (cylindrical member  22  or knob  24 ), the gears  304  and  310  couple the adjustment knob to the rack  302 . The adjustment knob, gears  304  and  310 , and the rack  302  can be arranged so that the portion of the mounting bracket  14  that is arranged to be attached to the archery bow  99  is positioned between the rack  302  and the adjustment knob. In that case, once the archery sight assembly  10  is attached to the archery bow  99  (via mounting bracket  14 ; bow  99  indicated by dashed lines in  FIG. 13 ), the rack  302  is positioned forward of the riser of the bow  99  and the adjustment knob is positioned rearward of the riser. This can be advantageous, for example, in that it enables an archer to see the position setting of the archery sight assembly  10  (e.g., the relative positions of scale  21  and pointer  200 ) while the archer holds the bow at full draw. A conventional archery sight positioning mechanism (based on a lead screw coupled via a mating nut on bearing slide  140 ) typically has a vertical adjustment knob located below the bearing side  140  in front of the riser, where it is difficult for the archer to see. 
     In addition to (or instead of) being arranged to position the knob behind the riser, the gears  304  and  310  can be arranged as a set of reduction gears to reduce the linear motion of the rack  302  relative to rotation of the adjustment knob. Such an arrangement enables more precise adjustment of the position of the archery sight  12 . Any desired degree of gear reduction can be employed; in the example of  FIG. 13 , a reduction ratio is determined by gear  304  and the gear  310  that is engaged with gear  304 . An analogous adaptation cannot be implemented conveniently for a conventional archery sight assembly that incorporates a lead screw. 
     It is intended that equivalents of the disclosed exemplary embodiments and methods shall fall within the scope of the present disclosure or appended claims. It is intended that the disclosed exemplary embodiments and methods, and equivalents thereof, may be modified while remaining within the scope of the present disclosure or appended claims. 
     For purposes of the present disclosure and appended claims, the conjunction “or” is to be construed inclusively (e.g., “a dog or a cat” would be interpreted as “a dog, or a cat, or both”; e.g., “a dog, a cat, or a mouse” would be interpreted as “a dog, or a cat, or a mouse, or any two, or all three”), unless: (i) it is explicitly stated otherwise, e.g., by use of “either . . . or”, “only one of . . . ”, or similar language; or (ii) two or more of the listed alternatives are mutually exclusive within the particular context, in which case “or” would encompass only those combinations involving non-mutually-exclusive alternatives. For purposes of the present disclosure or appended claims, the words “comprising,” “including,” “having,” and variants thereof shall be construed as open ended terminology, with the same meaning as if the phrase “at least” were appended after each instance thereof. 
     In the appended claims, if the provisions of 35 USC §112 ¶ 6 are desired to be invoked in an apparatus claim, then the word “means” will appear in that apparatus claim. If those provisions are desired to be invoked in a method claim, the words “a step for” will appear in that method claim. Conversely, if the words “means” or “a step for” do not appear in a claim, then the provisions of 35 USC §112 ¶ 6 are not intended to be invoked for that claim.