Patent Publication Number: US-8534269-B2

Title: Compound archery bow with replaceable draw length adjustment modules

Description:
This application claims priority from U.S. application 61/156,495 filed Feb. 28, 2009. 
    
    
     The present disclosure relates to compound archery bows having pulleys at the ends of the bow limbs to control the force/draw characteristics of the bow, and more particularly to compound archery bows having a draw length module removably mounted on at least one of the pulleys for adjusting bow draw length. 
     BACKGROUND AND SUMMARY OF THE DISCLOSURE 
     Single-cam and dual-cam compound archery bows have a power cam mounted on one or both ends of the bow limbs to control the draw force on the bowstring and the bending of the bow limbs as the bowstring is drawn. In single-cam bows, there is a power cam on the end of one bow limb with two let-out groves to facilitate let-out of bowstring as the bow is drawn, and a power take-up groove to take up a cable that can be anchored to the axle of a single groove idler wheel located on the opposite limb. In dual-cam bows, power cams are mounted on the ends of both limbs, with each including grooves or groove segments to control let-out of the bowstring on the opposing cam and power take-up grooves to take up cable that can be anchored at its opposing cam axle. More recently there have been hybrid cam systems that incorporate a mixture of both systems; there is a power cam on the end of one bow limb, and a two groove wheel on the end of the other bow limb to facilitate control or time take-up of a power cable at the power cam, and let-out of bowstring and control cables at the power cam as the bowstring is drawn. The power cam or cams may include a draw length control module adjustably and/or removably mounted on the power cam for adjusting the draw length of the bow. 
     In conventional bows of the described character having one or more adjustably or replaceably mounted draw length modules, adjustment and/or replacement of the module(s) can be made without concern for cable length because the power cable typically is anchored independently of its cam to an axle of the cam or wheel opposite its take-up and its effective length is not affected when draw length modules are changed to alter draw length. More recently there has been a new two-cam design where the power cable groove has both a let-out portion and a take-up portion on each cam. When modules are used to change draw length with this cam system, there is a problem with increasing cable slack as the draw length is decreased. A way to address this situation is to change power cables when the bow draw length is adjusted. A general object of the present disclosure is to provide a compound archery bow with draw length adjustment modules that automatically compensate for slackening that would otherwise occur in the power cable(s) as the draw length is adjusted. 
     The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other. 
     A compound archery bow in accordance with one aspect of the present disclosure includes a bow handle having projecting limbs, and first and second pulleys mounted on the limbs for rotation around respective axes. A bowstring cable extends from a bowstring anchor through a bowstring let-out groove on the first pulley and then toward the second pulley. A first power cable extends from a first power cable anchor toward the second pulley, and a second power cable extends from the second pulley through a power cable take-up arrangement on the first pulley to a second power cable anchor on the first pulley. Draw of the bowstring cable away from the handle lets out bowstring cable from the bowstring let-out groove, rotates the first pulley around the first axis, and takes up the second power cable into the second power cable take-up arrangement on the first pulley. A set of at least first and second bowstring cable draw length adjustment modules is provided for alternate mounting on the first pulley to adjust draw length of the bowstring cable away from the handle. Each of the modules includes a first portion for mounting adjacent to the first axis, an intermediate portion that includes a power cable take-up groove that constitutes at least part of the power cable take-up arrangement on the first pulley, and a heel portion for mounting spaced from the first axis and adjacent to the power cable anchor such that the power cable take-up groove extends around the heel to a position adjacent to the power cable anchor. The heel is larger on one of the modules than on the other. 
     A compound archery bow in accordance with another aspect of the present disclosure includes a bow handle having projecting limbs, and first and second pulleys mounted on the limbs for rotation around respective axes. A bowstring cable extends from a bowstring anchor through a bowstring let-out groove on the first pulley and then toward the second pulley. A first pulley power cable let-out portion of a power cable groove extends a power cable from the first pulley toward the second pulley take-up portion of the power cable groove, and a second pulley power cable let-out portion of the power cable groove extends a power cable from the second pulley to a power cable take-up arrangement on the first pulley. Draw of the bowstring cable away from the handle lets out bowstring cable from the bowstring let-out groove, rotates the first pulley around the first axis as it lets out the first power cable and takes up the second power cable into the second power cable take-up arrangement on the first pulley and rotates the second pulley around the second axis as it lets out the second power cable and takes up the first power cable into the first power cable take-up arrangement on the second pulley. A set of at least first and second bowstring cable draw length adjustment modules is provided for alternate mounting on the pulleys to adjust draw length of the bowstring cable away from the handle. Each of the modules includes a first portion for mounting adjacent to the first axis, an intermediate portion that includes a power cable take-up groove that constitutes at least part of the power cable take-up arrangement on the first pulley, and a heel portion for mounting spaced from the first axis and adjacent to the power cable anchor such that the power cable take-up groove extends around the heel to a position adjacent to the power cable anchor. In accordance with this aspect of the present disclosure, the size varies from one set to another and becomes larger as the draw length becomes shorter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure, together with additional objects, features, advantages and aspects thereof, will best be understood from the following description, the appended claims and the accompanying drawings, in which: 
         FIG. 1  is a side elevational view of a compound archery bow in accordance with one exemplary embodiment of the present disclosure; 
         FIGS. 1A and 1B  are fragmentary enlarged elevational views of the portions of  FIG. 1  within the areas  1 A and  1 B respectively; 
         FIG. 2  is a side elevational view of the bow in  FIG. 1  with draw length adjustment modules on the pulleys, which are different from those in  FIGS. 1-1B ; 
         FIGS. 2A and 2B  are fragmentary elevational views on an enlarged scale of the portions of  FIG. 2  within the respective areas  2 A and  2 B; 
         FIG. 3  is a side elevational view of the bow of  FIGS. 1 and 2  with a third draw length adjustment module mounted on each of the pulleys; 
         FIGS. 3A and 3B  are elevational views on an enlarged scale of the portions of  FIG. 3  within the respective areas  3 A and  3 B; 
         FIG. 4  is a fragmentary elevational view of the upper and lower pulleys in  FIGS. 1-3  with all three draw length adjustment modules superimposed for purposes of comparison; 
         FIGS. 5A-5C  are elevational views of the draw length adjustment modules in  FIGS. 1-3  respectively; 
         FIG. 6  is an elevational view of the cam base in the upper pulley of  FIGS. 1A ,  2 A and  3 A; 
         FIG. 7  is a side elevational view of the bow in  FIG. 1  in the fully drawn condition; 
         FIG. 8  is a side elevational view of a compound archery bow in accordance with another exemplary embodiment of the present disclosure; 
         FIG. 8A  is an end elevational view of the bow in  FIG. 8 ; 
         FIG. 8B  is a fragmentary elevational view on an enlarged scale of the pulleys in the bow of  FIGS. 8 and 8A ; 
         FIG. 9  is a fragmentary side elevational view of pulleys in a compound archery bow in accordance with another exemplary embodiment of the present disclosure with the bow handle and limbs removed for illustration; 
         FIG. 9A  is a fragmentary elevational view of the pulleys in  FIG. 9  viewed from the opposite side; 
         FIG. 9B  is an end elevational view of the pulleys in  FIG. 9 ; and 
         FIG. 9C  is an end elevational view similar to that of  FIG. 9B  but with the cables removed for illustration. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  illustrates a dual-cam compound archery bow  30  in accordance with one exemplary embodiment of the present disclosure as including a handle  26  of aluminum or other relatively rigid construction having spaced risers with limb-mounting surfaces at each end. A pair of flexible resilient limbs  25  of fiber-reinforced resin or other suitable resilient construction are mounted on the respective handle risers and project away from handle  26 . A lower pulley  32  ( FIGS. 1 and 1B ) is mounted on an end of limb  25  for rotation around the axis of an axle  14 , and an upper pulley  34  ( FIGS. 1 and 1A ) is mounted on an end of upper limb  25  for rotation around the axis of an associated axle  14 . Bow  30  of  FIGS. 1-1B  is a dual-cam bow in which pulleys  32 ,  34  are similar in function and preferably near minor images of each other. (One of the pulleys may be slightly larger than the other to compensate for the handle arrow rest not being at the true center of the bow. Some pulleys also can be made non-identical in areas that are non-functional to create a desired difference in appearance.) 
     A bowstring cable  24  ( FIGS. 1-1B ) extends from an anchor  17  ( FIGS. 1A ,  1 B and  6 ) on upper pulley  34  through a bowstring let-out groove  12  extending around the periphery of pulley  34  and then toward pulley  32 . In the exemplary embodiment, bowstring cable  24  extends at pulley  32  ( FIG. 1B ) through a peripheral bowstring let-out groove  12  to an anchor  17 . A first power cable  27  extends from an anchor  18  on pulley  34  around a let-out groove  23  ( FIG. 1A ) toward pulley  32 , and then at pulley  32  through a portion of a cable take-up groove  7  to an anchor  16  ( FIG. 1B ). A second power cable  28  extends from a power cable let-out groove  23  on pulley  32  toward pulley  34 , at which cable  28  extends through a take-up groove  7  to an anchor  16 . 
     Upper pulley  34  preferably comprises a generally flat base  36  ( FIG. 6 ) of plastic or, more preferably, metal construction having bowstring let-out groove  12  extending around its periphery. As shown in  FIGS. 1-1B  and  6 , base  36  preferably includes a full or partial hub  38  with a full or partial peripheral groove that forms part of power cable let-out groove  23 . A plurality of draw stop adjustment openings  15  are provided for purposes to be described. Power cable anchor  18  and power cable anchor  16  are mounted on base  36 , as is bowstring anchor  17  on the reverse side (see  FIG. 9A ). A plurality of openings  10  are provided for mounting a draw length adjustment module  19  ( FIGS. 1-1B  and  5 A),  20  ( FIGS. 2-2B  and  5 B) or  21  ( FIGS. 3-3B  and  5 C). (Three sets of modules are illustrated for the exemplary embodiment. There are at least two sets for each pulley, and there could be more than three sets for a greater range of adjustment, for example.) 
     Referring now to  FIGS. 5A-5C , each draw length module  19 ,  20 ,  21  includes a boss  8  for registry with partial or complete hub  38  both for aligning the draw length module on the base and continuing the let-out groove  23  that extends around the hub and boss. From boss  8 , groove  7  in each module extends in an arc to a heel  9  remote from the boss. The lengths of the arcs in the several modules and the sizes of the heels are coordinated with the adjustment length associated with each module both for adjusting bowstring draw length and for taking up the associated power cable slack, as will be described. Each module also includes openings  40 , preferably internally threaded openings, for alignment with openings  10  in base  36  for removably mounting the modules on the base.  FIGS. 1-1B  illustrate bow  30  and pulleys  32 ,  34  with draw length modules  19  mounted on the respective pulleys. The modules  19  are the draw length modules associated with the shortest draw length in this exemplary embodiment, with modules  20  ( FIGS. 2-2B  and  5 B) being medium draw length modules and modules  21  ( FIGS. 3-3B  and  5 C) being long-draw modules. Short draw module  19  has an enlarged heel  9   a  as compared with the medium heel  9   b  on module  20  and the short heel  9   c  on module  21 . 
     With short-draw module  19  mounted on pulleys  32 ,  34  as shown in  FIGS. 1-1B , cable  28  extends around heel  9   a  to anchor  16  on upper pulley  34  and cable  27  extends around heel  9   a  to anchor  16  on lower pulley  32 . As bowstring cable  24  is drawn away from handle  26  from the undrawn condition of  FIG. 1  toward the fully drawn condition of  FIG. 7 , upper pulley  34  rotates counterclockwise in  FIG. 1A  and lower pulley  32  rotates clockwise in  FIG. 1B . The upper end of cable  27  and the lower end of cable  28  are let out from grooves  23  while the upper end of cable  28  and the lower end of cable  27  are taken up into grooves  7  that extend around heels  9   a  on the respective modules. The extended dimensions of heels  9   a  provide extra area for take-up of the power cables to eliminate slack, and may also provide an enhanced lever on the respective pulleys to take up the power cables. Medium-length draw modules  20  in  FIGS. 2-2B  and  5 B have smaller heels  9   b  because the medium-length module requires less taking up of slack in the power cables. Likewise, the long-draw modules  21  in  FIGS. 3-3B  and  5 C have still shorter heels  9   c  because even less slack needs to be taken up when this module is used.  FIG. 4  provides a comparison of the geometries of modules  19 - 21  on pulleys  32 ,  34 . (It will be understood in practice that the modules are mounted individually and not simultaneously on base  36 .) 
     In the bow and module system of  FIGS. 1-7 , let-out grooves  23  and take-up grooves  7  on each pulley  32 ,  34  preferably are aligned effectively to form a continuous groove as disclosed in U.S. application Ser. No. 12/290,750, although this is not necessary in accordance with the present disclosure in its broadest aspects. 
       FIG. 7  is an elevational view of bow  30  in the fully drawn condition and long-draw modules  21  in place. A draw stop post  22  can be adjustably positioned in openings  15  on one or both pulleys to engage one or both limbs. Draw stop post  22  engages bow limb  25  at full draw, as best seen in  FIG. 7 . 
       FIGS. 8-8B  illustrate a dual-cam bow  50  that is similar in many respects to bow  30  discussed above. Elements of bow  50  (and of bow  60  in  FIGS. 9-9C ) that are the same as or similar to corresponding elements in bow  30  are indicated by correspondingly identical reference numerals. Only the differences between the bows will be discussed. In bow  50 , upper pulley  52  and lower pulley  54  feature draw length modules  21  (or  19  or  20 ) on both sides of the respective pulleys, rather than on just one side as in  FIGS. 1-4 . Power cable  28  is coupled by yokes  56  to pairs of split ends  28   a ,  28   b  that are received on respective opposite sides of upper pulley  52  and lower pulley  54 . In the same way, power cable  27  is coupled by yokes  58  to split ends  27   a ,  27   b  that are received on respective opposite sides of pulleys  52 ,  54 . This modification helps balance the forces applied to axles  14  and limbs  25 . 
       FIGS. 9-9C  illustrate a compound bow  60  (the bow handle and limbs are not shown for simplicity). In this embodiment, a draw length module  21  (or  19  or  20 ) is mounted on only one side of upper pulley  62  and lower pulley  64 . A power cable let-out groove  66  is mounted on the opposing side of each pulley and can be part of a hub or a module to be changed with the draw length module. Thus, power cable  28  is secured to anchor  16  at upper pulley  62 , and extends to a yoke  68  adjacent to lower pulley  64 , from which split cable ends  28   c ,  28   d  extend to module  21  and module  66  respectively. In the same way, power cable  27  extends from module  21  on lower pulley  64  to a yoke  69 , from which split ends  28   c ,  28   d  extend to module  21  and module  66  on upper pulley  62  respectively. This again helps balance forces on the pulley axles and the bow limbs. 
     There thus has been disclosed a compound archery bow that fully satisfies all of the objects and aims previously set forth. The bow has been disclosed in conjunction with several exemplary embodiments, and additional modifications and variations have been discussed. A dual cam bow preferably uses a portion of the same grove at each cam for the let-out and take-up of the power cables. The bow uses modules with heel extensions or levers to adjust cable length to take up cable slack without adjusting cable length when changing draw length modules. The bow preferably uses modules that are independent of the axle bosses. In the embodiment of  FIGS. 8-8B , there are two power cable let-out grooves and two power cable take-up grooves per cam to help reduce torque on the limbs. In the embodiment of  FIGS. 9-9C , there are two power cable let-out grooves and one power cable take-up groove per cam to help reduce torque on the limbs. The boss may use split cables when using two let-outs and one or two take-up grooves. Other modifications and variations readily will suggest themselves to persons of ordinary skill in the art in view of the foregoing description. The disclosure is intended to embrace all such modifications and variations as fall within the spirit and broad scope of the appended claims.