Patent Publication Number: US-10767957-B2

Title: Compound bow with servicing strings

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Patent Application No. 62/473,155, filed Mar. 17, 2017, the entire content of which is hereby incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates generally to archery bows and more specifically to compound archery bows. 
     Compound bows are known in the art. Compound bows often include rotating members, a bowstring and at least one cable segment. 
     Servicing and maintenance of compound bows often requires a bow press, which tends to be a large machine capable of flexing the limbs of the bow to relieve tension from the bowstring and cable segments. Bow presses are often required in order to change bowstring and cable segments, to change cam track modules on rotatable members, etc. 
     There remains a need for novel archery bow designs that allow for servicing and maintenance of a compound bow without the need for a bow press. 
     All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety. 
     Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below. 
     A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims. 
     BRIEF SUMMARY OF THE INVENTION 
     In some embodiments, a method comprises attaching a servicing string to the first rotatable member and the second rotatable member of a compound archery bow. The servicing string retains the first rotatable member and the second rotatable member in a non-brace orientation, for example in a partially drawn orientation. The bowstring is removed from the compound archery bow. A servicing cable is attached to the first rotatable member and the second rotatable member, and the servicing string is detached from at least one of the first rotatable member or the second rotatable member. The servicing cable is let down, unloading the compound archery bow. In some embodiments, letting down the servicing cable comprises rotating the first rotatable member and second rotatable member past their orientations in a brace condition. 
     In some embodiments, a power cable is removed from the archery bow. In some embodiments, a replacement power cable is installed on the archery bow. 
     In some embodiments, the servicing string is reinstalled on the bow and the servicing cable is removed. 
     In some embodiments, a replacement bowstring is installed on the bow and the servicing string is removed. 
     In some embodiments, a kit comprises a compound archery bow, a servicing string and a servicing cable. The bow comprises a first rotatable member, a second rotatable member and a bowstring. The servicing string is arranged to engage the first rotatable member and the second rotatable member. A length of the servicing string is less than a length of the bowstring. The servicing cable is arranged to engage the first rotatable member and the second rotatable member. A length of the servicing string is greater than the length of the bowstring. 
     These and other embodiments which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages and objectives obtained by its use, reference can be made to the drawings which form a further part hereof and the accompanying descriptive matter, in which there are illustrated and described various embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A detailed description of the invention is hereafter described with specific reference being made to the drawings. 
         FIG. 1  shows an embodiment of a compound bow with an embodiment of a servicing string and an embodiment of a servicing cable. 
         FIGS. 2 and 3  show a bowstring being removed from an archery bow using a servicing string. 
         FIGS. 4-8  show a procedure for removing power cables from a bow using a servicing cable. 
         FIG. 9  shows an embodiment of a bowstring along with an embodiment of a servicing string and an embodiment of a servicing cable. 
         FIG. 10  shows another embodiment of an archery bow. 
         FIG. 11  shows an embodiment of a crossbow. 
         FIG. 12  shows an embodiment of a single cam bow. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While this invention may be embodied in many different forms, there are described in detail herein specific embodiments of the invention. This description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated. 
     For the purposes of this disclosure, like reference numerals in the figures shall refer to like features unless otherwise indicated. 
       FIG. 1  shows an embodiment of an archery bow  10  comprising a first rotatable member  20 , a second rotatable member  30 , a bowstring  40  and at least one power cable  50 . 
     In some embodiments, an archery bow  10  comprises a riser  12 , a first limb  14  supported by the riser  12  and a second limb  16  supported by the riser  12 . In some embodiments, the first limb  14  supports the first rotatable member  20  and the second limb  16  supports the second rotatable member  30 . 
     In some embodiments, the first rotatable member  20  comprises a first bowstring track  21  and a first bowstring terminal  22 . In some embodiments, the second rotatable member  30  comprises a second bowstring track  31  and a second bowstring terminal  32 . In some embodiments, the bowstring  40  is attached between the rotatable members  20 ,  30 . In some embodiments, the bowstring  40  comprises a first end  41  comprising a loop and a second end  45  comprising a loop. In some embodiments, the first end  41  of the bowstring  40  is attached to the first bowstring terminal  22 , and the bowstring  40  comprises a first wrapped portion  42  oriented in the first bowstring track  21 , for example when the bow  10  is in a brace condition. In some embodiments, the second end  45  of the bowstring  40  is attached to the second bowstring terminal  32 , and the bowstring  40  comprises a second wrapped portion  44  oriented in the second bowstring track  31 , for example when the bow  10  is in a brace condition. 
     In some embodiments, the first rotatable member  20  comprises a first cam track  23 , and the first power cable  50  is arranged to be taken up by the first cam track  23  as the bow  10  is drawn. In some embodiments, the first rotatable member  20  comprises a first power cable terminal  24 . In some embodiments, a first end  51  of the first power cable  50  is attached to the first power cable terminal  24 , and the first power cable  50  extends toward the second rotatable member  30 . In some embodiments, the first power cable  50  attaches to the second rotatable member  30 , although the first power cable  50  can also attach to an axle, to the second limb  16 , or any other suitable portion of the bow  10 . As shown in  FIG. 1 , the second rotatable member  30  comprises a first force vectoring anchor  35 , and a second end  53  of the first power cable  50  is attached to the first force vectoring anchor  35 . 
     In some embodiments, the archery bow  10  comprises a second power cable  56 . In some embodiments, the second rotatable member  30  comprises a second cam track  33 , and the second power cable  56  is arranged to be taken up by the second cam track  33  as the bow  10  is drawn. In some embodiments, the second rotatable member  30  comprises a second power cable terminal  34 . In some embodiments, a first end  57  of the second power cable  56  is attached to the second power cable terminal  34 , and the second power cable  56  extends toward the first rotatable member  20 . In some embodiments, the second power cable  56  attaches to the first rotatable member  20 , although the second power cable  56  can also attach to an axle, to the first limb  14 , or any other suitable portion of the bow  10 . As shown in  FIG. 1 , the first rotatable member  20  comprises a second force vectoring anchor  25 , and a second end  59  of the second power cable  56  is attached to the second force vectoring anchor  25 . 
     In some embodiments, the first rotatable member  20  comprises a first servicing post  26 . In some embodiments, the second rotatable member  30  comprises a second servicing post  36 . A servicing post  26 ,  36  can have any suitable size, shape or configuration. In some embodiments, a servicing post  26 ,  36  comprises a stem and an enlarged flange portion. 
     In some embodiments, a servicing string  70  is provided with the bow  10 . In some embodiments, a servicing string  70  comprises a tool that allows a user to change a bowstring  40  without any other tools. In some embodiments, a length of the servicing string  70  is less than a length of the bowstring  40 . In some embodiments, the first end  72  of the servicing string  70  is arranged to engage the first rotatable member  20  and the second end  74  of the servicing string  70  is arranged to engage the second rotatable member  30 . In some embodiments, each end  72 ,  74  comprises a hook, a loop, or another suitable shape. In some embodiments, the first end  72  of the servicing string  70  is arranged to engage the first servicing post  26  and the second end  74  of the servicing string  70  is arranged to engage the second servicing post  36 . 
     In some embodiments, a length of the servicing string  70  is less than a distance between the first servicing post  26  and the second servicing post  36  when the bow  10  is in the brace condition. 
     The servicing string  70  can be made of any suitable material and can have any suitable configuration. In some embodiments, the servicing string  70  acts as a tension member when used to service the bow  10 . In some embodiments, the servicing string  70  comprises a material similar to the material of the bowstring  40 , such as a polymeric material or materials disclosed in U.S. Pat. No. 7,231,915, the entire disclosure of which is hereby incorporated herein by reference. 
     In some embodiments, the servicing string  70  is made to be as small, light and compact as possible. In some embodiments, the servicing string  70  consists of polymeric material. In some embodiments, the servicing string  70  consists of a body length of cable and end loops  72 ,  74 . 
     In some embodiments, a servicing cable  80  is provided with the bow  10 . Desirably, a length of the servicing cable  80  is greater than the length of the bowstring  40 . In some embodiments, the first end  82  of the servicing cable  80  comprises a loop or other structure suitable to engage a rotatable member  20 , and the second end  84  comprises a loop or other structure suitable to engage a rotatable member  30 . In some embodiments, the first end  82  is arranged to engage the first bowstring terminal  22  and the second end  84  is arranged to engage the second bowstring terminal  32 . 
     In some embodiments, a servicing cable  80  comprises materials similar to the servicing string  70 . In some embodiments, the servicing cable  80  consists of polymeric material. In some embodiments, the servicing cable  80  consists of a body length of cable and end loops  82 ,  84 . 
     In some embodiments, a method comprises using a servicing string  70  to remove the bowstring  40  of the bow  10 . In some embodiments, the method further comprises installing a replacement bowstring  40  on the bow  10 . 
     In some embodiments, a method comprises using a servicing cable  80  to remove one or more power cables  50 ,  56 . In some embodiments, the servicing cable  80  is used to unwind the rotatable members  20 ,  30 , thereby dissipating stored energy in a controlled manner and relaxing the limbs  14 ,  16 . When the bow  10  is at or near a relaxed condition, the power cable(s)  50 ,  56  can be removed from the bow  10 . In some embodiments, the method further comprises installing one or more replacement cable(s)  50 ,  56  on the bow  10 . In some embodiments, the method further comprises loading the limbs  14 ,  16  and returning the bow  10  to its brace condition. 
       FIGS. 2-9  illustrate a sequence of using a servicing string  70  to change a bowstring  40  and using a servicing cable  80  to change a power cable  50 . 
       FIG. 2  shows an embodiment of a servicing string  70  attached between servicing posts  26 ,  36  of the rotatable members  20 ,  30 . 
     In some embodiments, the limb fasteners  18  can be backed out as far as possible without removing the limb fasteners  18 , to reduce the loading on the limbs. 
     In some embodiments, a method comprises providing a bow  10  and attaching a servicing string  70  between the rotatable members  20 ,  30 . In some embodiments, from a brace condition of the bow  10 , the bowstring  40  can be pulled to orient the bow  10  in a partially drawn condition, wherein the rotatable members  20 ,  30  are advanced rotationally from their brace orientations. The servicing string  70  can be attached between the rotatable members  20 ,  30 , for example by attaching the first end  72  to the first servicing post  26  and attaching the second end  74  to the second servicing post  36 . When the servicing string  70  is properly installed, any force being applied to the bowstring  40  in the direction of draw can be removed. In some embodiments, the servicing string  70  will be placed in tension, thereby retaining the rotatable members  20 ,  30  in a slightly drawn orientation. The bowstring  40  is no longer in tension and can be removed from the bow  10 . 
       FIG. 3  shows the bow  10  of  FIG. 2  with the bowstring  40  removed from the bow  10 . The servicing string  70  is retaining the rotatable members  20 ,  30  is a slightly drawn orientation. In some embodiments, the first end  41  of the bowstring  40  is detached from the first bowstring terminal  22  and the second end  45  of the bowstring  40  is detached from the second bowstring terminal  32 . The bowstring  40  can be detached completely from the rotatable members  20 ,  30  and removed from the bow  10 . 
     At this point, in some embodiments, another bowstring  40  can be installed on the bow  10  and the servicing string  70  can be removed. Alternatively, if changing a power cable  50 ,  56  is desired, the servicing string  70  can remain attached between the rotatable members  20 ,  30 , and the servicing cable  80  can be used. 
       FIG. 4  shows the bow  10  of  FIG. 3  with an embodiment of a servicing cable  80  attached to the rotatable members  20 ,  30 . The servicing string  70  is still under tension and retaining the rotatable members  20 ,  30  in a fixed orientation. 
     In some embodiments, the servicing cable  80  is longer than the bowstring  40 . In some embodiments, the servicing cable  80  is installed in place of the bowstring during the servicing operation. In some embodiments, the first end  82  of the servicing cable  80  is attached to the first bowstring terminal  22  of the first rotatable member  20  and a length portion of the servicing cable  80  is oriented in the first bowstring track  21 . In some embodiments, the second end  84  of the servicing cable  80  is attached to the second bowstring terminal  32  of the second rotatable member  30  and a length portion of the servicing cable  80  is oriented in the second bowstring track  31 . 
     When the servicing cable  80  is properly installed between the rotatable members  20 ,  30 , the servicing cable  80  can act as a bowstring and be used to apply a draw force to the rotatable members  20 ,  30 . Forces applied by the servicing cable  80  can rotate the rotatable members  20 ,  30  and relieve tension in the servicing string  70 , and the servicing string  70  can be detached from at least one of the rotatable members  20 ,  30 . 
       FIG. 5  shows the bow  10  of  FIG. 4  with the servicing string  70  detached from the first rotatable member  20 . The servicing string  70  no longer biases the rotatable members  20 ,  30 , and a force applied to the servicing cable  80  is used to counteract energy stored in the bow  10 . The servicing cable  80  can be let down in a controlled manner, allowing the rotatable members  20 ,  30  rotate back to the brace orientation, and then past the brace orientation to unwind and unload the bow  10 . 
     In  FIG. 5 , the rotatable members  20 ,  30  have rotated past their brace condition orientation and the limbs  14 ,  16  are less flexed than in the brace condition. The length of the servicing cable  80  allows the rotatable members  20 ,  30  to unwind further as the servicing cable  80  is let down. 
       FIG. 6  shows the bow  10  of  FIG. 5  with the servicing cable  80  almost fully let down. The limbs  14 ,  16  have straightened and relaxed. In some embodiments, the servicing cable  80  is wrapped around an entire perimeter of the first rotatable member  20  and the second rotatable member  30 . In some embodiments, the bowstring tracks  21 ,  31  extend around an entire outer perimeter of the rotatable member  20 ,  30 . In some embodiments, the servicing cable  80  wraps more than 360 degrees around the rotatable member  20 ,  30 , and in some embodiments, a portion (e.g.  86 ) of the servicing cable  80  overlaps another portion of the servicing cable  80 . In some embodiments, a depth of the bowstring track  21 ,  31  changes along its length. In some embodiments, a bowstring track  21 ,  31  is deep enough to contain two layers of servicing cable  80 . In some embodiments, certain portion(s) of the bowstring track  21 ,  31  are deep enough to contain two layers of servicing cable  80 , while other portion(s) have a depth suitable for one layer of servicing cable  80 . 
       FIG. 7  shows the bow  10  of  FIG. 6  with no external force being applied to the servicing cable  80 . Desirably, the bow  10  has relaxed sufficiently that the power cable(s)  50 ,  56  can be removed. The servicing cable  80  can also be removed if desired. 
       FIG. 8  shows the bow  10  of  FIG. 7  after the first end  51  of the first power cable  50  has been detached from the first power cable terminal  24  of the first rotatable member  20 , and the first end  57  of the second power cable  56  has been detached from the second power cable terminal  34  of the second rotatable member  30 . 
     The bow  10  is now completely unstrung. The power cables  50 ,  56  can be removed from the bow  10  entirely and replaced with new power cables  50 ,  56 . 
     The bow  10  can be strung using a servicing cable  80  and servicing string  70  is a procedure that is essentially reversed when compared to the unstringing process. In some embodiments, when power cables  50 ,  56  are properly attached to bow  10 , the servicing cable  80  can be used to wind the rotatable members  20 ,  30 , thereby loading the bow  10  and flexing the limbs  14 ,  16 . The rotatable members  20 ,  30  can be wound past their brace orientation to a slightly drawn condition, and the servicing string  70  installed between the rotatable members  20 ,  30 , resulting in a condition as shown in  FIG. 4 . The servicing cable  80  can be removed and a bowstring  40  can be installed, and the servicing string  70  can be removed, allowing the bow  10  return to its brace condition. 
     In some embodiments, a servicing string  70  and servicing cable  80  allow an archer to perform a complete unstringing of strings and cables from a bow  10  without the need for any tools. Strings and cables can be replaced in the field, without the need for a bow press or any external components arranged to apply large forces to the bow  10 . 
       FIG. 9  shows an embodiment of a bowstring  40 , an embodiment of a servicing string  70  and an embodiment of a servicing cable  80 . 
     In some embodiments, the bowstring  40  is longer than the servicing string  70  and the servicing cable  80  is longer than the bowstring  40 . The specific lengths of the servicing string  70  and the servicing cable  80  may be chosen depending upon the specifics of the bow  10 . 
       FIG. 10  shows another embodiment of a bow  10  and an embodiment of a servicing string  70 . In some embodiments, a length of the servicing string  70  is less than an axle-to-axle distance of the bow  10 . In some embodiments, a length of the servicing string  70  is less than a distance between servicing posts  26 ,  36  in the brace condition. In some embodiments, a length of the servicing string  70  is greater than a minimum distance between the rotatable members  20 ,  30  in the brace condition. 
     The rotatable members  20 ,  30  shown in  FIG. 10  include bowstring tracks  21 ,  31  having portions  86  that include a depth suitable to contain two layers of servicing cable  80 . 
     In some embodiments, a rotatable member  20 ,  30  comprises a first terminal arranged to engage a bowstring, a second terminal arranged to engage a first cable, a third terminal arranged to engage a second cable, and a servicing post  26 ,  36 . 
     In some embodiments, the servicing post  26 ,  36  of a rotatable member  20 ,  30  is not attached to a bowstring  40  or power cable  50 ,  56 . 
     In some embodiments, the servicing string  70  is constructed an arranged to engage a servicing post  26  but configured to not engage terminals or posts provided for the bowstring  40  or power cables  50 ,  56 . For example, in some embodiments, a servicing post  26  is smaller than terminals provided for the bowstring  40  and power cables  50 ,  56 , and the servicing string  70  comprises a loop that will fit around a servicing post  26  but not a terminal provided for the bowstring  40  or a power cable  50 ,  56 . 
     In some embodiments, the bow  10  comprises a crossbow. 
       FIG. 11  shows an embodiment of a crossbow  11  comprising rotatable members  20 ,  30  that include respective servicing posts  26 ,  36 . A servicing string and a servicing cable can be used to unstring the bowstring  40  and power cables  50 ,  56  as previously described herein. 
     In some embodiments, a rotatable member  20  comprises a bowstring terminal  22 , a first power cable terminal  24 , a second power cable terminal  27  and a servicing post  26 . 
     In some embodiments, a servicing post  26  comprises a stem portion  64  and a flange  66 . In some embodiments, the servicing post  26  is constructed and arranged such that a bowstring  40  and/or power cables  50 ,  56  arranged to engage their respective terminals  22 ,  24 ,  27  will be unable to engage the servicing post  26 . In some embodiments, a size of the servicing post  26  is larger than terminal loops provided at the ends of the bowstring  40  and/or power cables  50 ,  56 . In some embodiments, a servicing post  26  is larger in size than other terminal posts  22 ,  24 ,  27  on the rotating member  20 . 
     In some embodiments, a servicing string and a servicing cable can be configured for use on a single cam archery bow. 
       FIG. 12  shows an embodiment of an archery bow  10  comprising a first rotatable member  20  comprising a cam track, a primary bowstring track  21  and a secondary bowstring track. A second rotatable member  30  comprises a pulley. In some embodiments, a power cable  50  is arranged to be taken up on the cam track. In some embodiments, the bowstring  40  comprises a first end attached to the first rotatable member  20 , an elongate portion that wraps around the second rotatable member  30  and a second end attached to the first rotatable member  20 . 
     In some embodiments, the first rotatable member  20  comprises a servicing post  26 . 
       FIG. 12  shows two embodiments of servicing strings  70  that can be used to unstring the bowstring  40 . In some embodiments, a servicing string  70  comprises a first end  72  arranged to engage the servicing post  26  and a second end  74  arranged to engage the second rotatable remember  30 . As shown in  FIG. 12 , the first end  72  comprises a terminal loop suitable to engage the servicing post and the second end  74  comprises a hook suitable to engage the second rotatable member  30 . In some embodiments, a length of the servicing string  70  is less than an axle-to-axle distance defined by the archery bow  10 . 
     In some embodiments, a servicing string  70   b  comprises a first end  72  arranged to engage the servicing post  26 , an elongate portion  73  arranged to engage the second rotatable member  30 , and a second end  74  arranged to engage the servicing post  26 . Thus, in some embodiments, both ends of a servicing string  70  engage the same servicing post  26 . In some embodiments, the elongate portion  73  can be passed through an aperture in the second rotatable member  30  to engage the second rotatable member  30 . In such embodiments, a length of the servicing string  70   b  is greater than an axle-to-axle distance defined by the archery bow  10 . The servicing string  70   b  may have a length that is less than the bowstring  40 . The arrangement of servicing string  70   b  can also be used in bows configured as shown in  FIG. 1 . 
     A servicing cable (not shown in  FIG. 12 ) can further be used to unwind the first rotatable member  20  and unload the bow  10 . For example, a servicing cable that is longer than the bowstring  40  can be installed in place of the bowstring  40 , the servicing string  70 / 70   b  can be removed and the servicing cable can allow unwinding of the rotatable member(s)  20 ,  30 . When the bow  10  is unloaded, the power cable  50  can be changed. 
     In some embodiment, the invention is directed to a method as described in the following paragraphs: 
     1. A method comprising: 
     attaching a servicing string to a first rotatable member and a second rotatable member of a compound archery bow, wherein the servicing string retains the first rotatable member and the second rotatable member in a non-brace orientation; and removing a bowstring from the compound archery bow. 
     2. The method of paragraph 1, wherein removing the bowstring comprises detaching the bowstring from the first rotatable member. 
     3. The method of paragraph 2, wherein removing the bowstring further comprises detaching the bowstring from the second rotatable member. 
     4. The method of paragraph 1, further comprising installing a replacement bowstring on the compound archery bow. 
     5. The method of paragraph 4, wherein installing the replacement bowstring comprises attaching the replacement bowstring to the first rotatable member. 
     6. The method of paragraph 5, wherein installing the replacement bowstring comprises attaching the replacement bowstring to the second rotatable member. 
     7. The method of paragraph 4, further comprising detaching the servicing string from the first rotatable member. 
     8. The method of paragraph 7, further comprising detaching the servicing string from the first rotatable member. 
     9. The method of paragraph 1, wherein the servicing string is shorter in length than the bowstring. 
     10. The method of paragraph 1, wherein the servicing string is shorter than an axle-to-axle distance of the compound archery bow. 
     11. The method of paragraph 1, further comprising attaching a servicing cable to the first rotatable member and the second rotatable member. 
     12. The method of paragraph 11, wherein the servicing cable is longer than the bowstring. 
     13. The method of paragraph 11, wherein the servicing cable is oriented in a bowstring track of the first rotatable member. 
     14. The method of paragraph 11, further comprising removing the servicing string. 
     15. The method of paragraph 14, further comprising allowing the first rotatable member and the second rotatable member to rotate past their brace orientations. 
     16. The method of paragraph 14, further comprising removing any external force being applied to the servicing cable. 
     17. The method of paragraph 14, further comprising removing a power cable of the compound archery bow. 
     18. The method of paragraph 17, further comprising installing a replacement power cable on the compound archery bow. 
     In some embodiments, an archery bow  10  is configured according to the following numbered paragraphs. 
     1. An archery bow comprising: 
     a first rotatable member comprising a body comprising an integrally formed first servicing post and a first bowstring track; 
     a second rotatable member comprising a body comprising an integrally formed second servicing post and a second bowstring track; 
     a bowstring extending between the first rotatable member and the second rotatable member; and 
     a servicing string constructed and arranged to engage the first servicing post and the second servicing post; 
     wherein the first servicing post and the second servicing post are separated by a distance when the bow is in a brace condition, a length of the servicing string being less than said distance. 
     2. The archery bow of paragraph 1, further comprising a servicing cable, the servicing cable being longer than the bowstring. 
     3. The archery bow of paragraph 1, wherein the first rotatable member defines a rotation axis, the first servicing post extending in a direction orthogonal to the rotation axis. 
     4. The archery bow of paragraph 1, wherein the first servicing post is integral portion of the first rotatable member. 
     5. An archery bow comprising: 
     a first rotatable member comprising a body comprising an integrally formed first servicing post and a first bowstring track; 
     a second rotatable member comprising a body comprising a second bowstring track; 
     a bowstring comprising a first end and a second end, the first end attached to the first rotatable member, the bowstring wrapping around the second rotatable member, the second end attached to the first rotatable member; and a servicing string comprising a first end arranged to engage the first servicing post, an elongate portion arranged to contact the second rotatable member and a second end arranged to engage the first servicing post. 
     The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this field of art. All these alternatives and variations are intended to be included within the scope of the claims where the term “comprising” means “including, but not limited to.” Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims. 
     Further, the particular features presented in the dependent claims can be combined with each other in other manners within the scope of the invention such that the invention should be recognized as also specifically directed to other embodiments having any other possible combination of the features of the dependent claims. For instance, for purposes of claim publication, any dependent claim which follows should be taken as alternatively written in a multiple dependent form from all prior claims which possess all antecedents referenced in such dependent claim if such multiple dependent format is an accepted format within the jurisdiction (e.g. each claim depending directly from claim  1  should be alternatively taken as depending from all previous claims). In jurisdictions where multiple dependent claim formats are restricted, the following dependent claims should each be also taken as alternatively written in each singly dependent claim format which creates a dependency from a prior antecedent-possessing claim other than the specific claim listed in such dependent claim below. 
     This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto.