Abstract:
An archery bow and cam apparatus having an anti-rotation cam stop mechanism which permits loosening of the bow string, loosening of a cable, or loosening of the bow string and a cable. The anti-rotation means may comprise an aperture or series of apertures through the cam and a member insertable in the aperture. The member can extend through the cam assembly and contact the limb of the bow to prevent the cam from rotating back to a resting or static position. The invention is particularly suited for a compound bow or compound crossbow having one or more cams, and a combination of a bow string and power cable, such the bow string may be detensioned by increasing the tension on the power cable, and vice versa, upon stopping free rotation of the cam.

Description:
FIELD OF THE INVENTION 
     The invention relates to archery bows, and specifically to a compound bow or compound cross bow of the type having a bow string, one or more power cables, and a cam or cams for tensioning the string and cable. The invention further relates to a system and method for loosening the bow string or one of the power cables to enable maintenance to be carried out on the loosened cable or string. 
     BACKGROUND 
     A compound archery bow typically comprises a rigid center riser, a handle grip and a pair of flexible limbs extending from the opposing end portions of the riser. The compound bow has the bow string attached to one or more pulleys (cams), + the pulleys to turn. This causes the pulleys to pull the cables, which in turn causes the limbs to bend and thus store energy. A single cam bow typically includes a wheel mounted to the upper limb and a cam assembly mounted to the lower limb (the terms upper and lower are purely for convenience of description). A dual cam bow includes a cam assembly on each of the upper and lower limbs. Power or tension cables are also connected between the two limbs via the cams and wheels. The cam assembly provides a mechanical advantage. 
     Proper stringing and tensioning of the bow strings and cables is important for achieving optimum performance. The bow string, and cables are adjusted to set the proper cam positioning and the desired length, by changing the position or replacing the draw module mounted to the cam assembly of the bow. Adjustments and maintenance also may be performed as the bow, materials in the limb, bow string and power cable change due to age and use. Other adjustments and maintenance may be performed to replace components such as the bow string or power cable; to add accessories to the bow such as a peepsight or silencer; or to change or modify other components. It is sometimes necessary or desirable to perform these operations in the field, often under adverse conditions. 
     Since the bow string and power cables are constantly under tension, repair work or maintenance on the bow, cam and strings or cables themselves requires a compressive force to squeeze or compress the bow limbs together and provide slack in the bow string or cables. Typically, a bow press is used for this purpose. A bow press is often relatively large and heavy, and usually is located in a repair shop and is not readily available in the field. Without a bow press, adjustments or repair to equipment in the field are difficult or impossible to perform. 
     One solution has been to provide a portable bow press, such as those disclosed in U.S. Pat. No. 5,022,377 to Stevens and U.S. Pat. No. 4,077,385 to Fredrickson. Another proposed solution is disclosed in U.S. Pat. No. 4,195,397 to Saunders and U.S. Pat. No. 4,074,409 to Smith, which disclose apparatus for use in the restringing of a compound bow which include a number of hooks attachable to string segments of the bow. 
     SUMMARY 
     In one embodiment, the disclosed and claimed concept relates to a cam and an associated cam stop which permits the user to prevent rotation of the cam in a selective fashion so as to permit loosening of the bow string, loosening of a cable or loosening of the bow string and a cable. The cam stop may comprise an aperture through the cam, which receives a pin or other lock member in a fashion which permits the pin to protrude laterally from the cam so as to engage a portion of the bow to prevent the cam from rotating past the engagement position and back to a static position. A series of apertures, may be provided in the cam to permit multiple engagement positions. A lock mechanism may be used on the limb of the bow for engaging the cam and locking the cam in a position rotated away from the static position. The lock mechanism may include a rigid stop or ratchet mechanism mounted on the limb and activated to prevent the cam from rotating in one or more directions. 
     To loosen the bow string in order to perform maintenance, the cam is rotated a few degrees, for example by a user pulling the bow string a few inches. At this point, the cam stop is actuated. The bow string may be released and the cam stop prevents rotation of the cam back to a resting position. As a result, the bow string is then maintained in loosened state. The force of the limbs diverging away from each other is wholly counteracted by the tension in the power cable. The cam stop prevents equalization of the tensioning force through the bow string, thereby permitting the bow string to remain loose and for maintenance on or replacement of the bow string. To loosen a power cable in order to perform maintenance, a similar procedure may be performed by pulling the power cable to cause rotation of the cam and actuating the cam stop. The cam stop prevents equalization of the tensioning force through the power cable and the limbs are held under tension by the bow string, thereby permitting the power cable to remain loose and for maintenance on or replacement of the power cable. 
     For a single cam bow, the power cable can be placed under tension and the bow string is loosened, allowing work to be performed on the bow string. Alternatively, for a single cam bow, the bow string can be placed under tension and the power cable is loosened, allowing work to be performed on the power cable. Additional work or maintenance may be performed on the cam, bow, bow string or cables with the rotation of the cam locked. For a dual cam bow, one of the bow strings or cables may be pulled to rotate the cam at the upper or lower limb, placing one of the power cables under tension and loosening the bow string and the second power cable. 
     According to an embodiment of the present disclosure, there is provided a cam for engaging a bow string and power cable of an archery bow, the archery bow having opposed limbs. The cam comprises: a cam body; a mount for rotatably mounting the cam body to one of the limbs about an axis; at least one first cam surface on the cam body for receiving the bow string; at least one second cam surface on the cam body for receiving the power cable; and a selectively actuatable cam stop to prevent rotation of the cam about the axis in a first direction beyond a first circumferential position when the cam stop is actuated. The first circumferential position permits detensioning of the bow string or the power cable when engaged to the cam surfaces. The cam stop may be de-actuated to permit free rotation of the cam body about the axis in either direction to restore tension on the bow string or power cable. 
     According to another embodiment of the present disclosure there is provided an archery bow comprising: a pair of opposed limbs; a bow string routed between said limbs; at least one power cable routed between said limbs; and at least one cam rotatably mounted to one of said limbs. The cam comprises a cam body, at least one first cam surface on the cam body for receiving the bow string and at least one second cam surface on the cam body for receiving the power cable. The bow includes a selectively actuatable cam stop to prevent rotation of the cam about the axis in a first direction beyond a first circumferential position when actuated. The first circumferential position permits detensioning of the bow string or the power cable. The cam stop may be de-actuated to permit free rotation of the cam body about the axis in either direction to restore tension on the bow string or power cable. 
     According to another embodiment of the present disclosure there is provided a method for decreasing tension in a bow string or power cable of an archery bow to perform maintenance thereon. The method comprising the steps of: providing an archery bow comprising a pair of opposed bow limbs, a bow string, at least one power cable, and at least one cam rotatably mounted to one of the limbs, the cam configured to equalize the tension on the power cable and bow string, the power cable and the bow string being under tension; rotating the cam in a first direction; and actuating a cam stop to prevent back-rotation of the cam in a second direction opposed to the first direction. Actuating the cam stop locks the cam at a first circumferential position thereby increasing tension in the power cable or the bow string, and decreasing tension in the other of the bow string or the power cable. 
     According to another embodiment of the present disclosure there is provided a method for decreasing tension in a bow string or power cable of an archery bow to perform maintenance thereon. The method comprises the steps of: providing an archery bow comprising an upper limb and an opposed lower limb, a bow string, at least two power cables, an upper cam rotatably mounted the upper limb, and a lower cam rotatably mounted to the lower limb, the upper cam and lower cam configured to equalize the tension on the power cables and the bow string, the power cables and the bow string being under tension; rotating one of the upper cam or the lower cam in a first direction; and actuating a cam stop to prevent back-rotation of the rotated upper or lower cam in a second direction opposed to the first direction. Actuating the cam stop locks the upper cam or lower cam at a first circumferential position thereby increasing tension in one of the power cables and decreasing tension in the bow string and in the other of the power cables. 
     Directional references employed in the specification or claims, such as “upper,” “lower,” “left,” “right,” “clockwise,” “counter-clockwise” and the like are employed for ease of description and are not intended to limit the scope of the invention in any respect. It will be readily apparent that an archery apparatus according to the present disclosure may be oriented in any direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following detailed description when read in connection with the accompanying drawings describes embodiments of the invention. The various features of the drawings are not necessarily to scale. 
         FIG. 1  is a perspective view of an single cam bow according to the present disclosure; 
         FIG. 2  is a detailed side view of the cam portion of a single cam bow and a cam lock, and related components according to the present disclosure; 
         FIG. 3  is a perspective view of a dual cam bow according to the present disclosure; 
         FIG. 4  is a detailed side view of a cam of a dual cam bow and a cam lock and related components according to the present disclosure; 
         FIG. 5  is a bottom view of the cam and cam lock of  FIG. 4  for a solid limb bow; 
         FIG. 5A  is a bottom view of the cam and cam lock of  FIG. 4  for a split limb bow; 
         FIG. 6  is a detailed side view of a bow and cam lock in a stored position; 
         FIG. 7  is a detailed side view of a cam and various alternative cam locks; 
         FIG. 8  is a detailed side view of the cam portion of a single cam bow and a cam lock, and related components according to an alternative embodiment of the present disclosure; and 
         FIG. 9  is a bottom view of the cam and cam lock of  FIG. 8 . 
     
    
    
     While the invention will be described in conjunction with the illustrated embodiments, it will be understood that it is not intended to limit the invention to such embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the scope of the invention as defined by this specification as a whole, including the appended claims. 
     DETAILED DESCRIPTION 
     In the following description, similar features have been given similar reference numerals. The apparatus and method are described below in relation to single and dual cam archery bows but will be understood by those skilled in the art to apply to other types of compound bows, including a cam and a half bow, binary cam bow or compound cross bow. 
       FIG. 1  illustrates a single cam archery bow  10  having a rigid riser  12  with an integral carrying handle  14 . Upper and lower limbs  16  and  17  extend from opposing ends of the riser  12 . Limbs  16  and  17  may be substantially parallel to each other or disposed at a diverging angle, depending on the desired features of the bow. Limbs  16  and  17  terminate at their distal ends in spaced forks  16   a ,  16   b  and  17   a ,  17   b  respectively. A freely rotatable wheel  20  is mounted to upper limb  16  at the top of the bow  10 , journalled on an axle (not shown) for free rotation in either direction. The axle spans the forks  16   a ,  16   b . A cam  22  is mounted to lower limb  17  on an axle  32  which spans the forks  17   a ,  17   b . A bow string  24  and power cable  26  are strung between the wheel  20  and cam  22 . A first end loop  24   a  of the bow string  24  is attached to the cam  22 . The bow string  24  is then routed around the wheel  20  and returns to cam  22 , and is fastened to cam  22  at a second end loop  24   b .  FIG. 1  also illustrates a member  28 , which comprises a component of the cam stop described below, stored in a slot in the carrying handle  14  for storage adjacent to a tool supporting body  30 . The member  28  can be stored in any convenient fashion, for example a clip may be provided at any convenient location on bow  10 , or the member  28  may be stored in a convenient receptacle within the bow  10 . 
       FIG. 2  provides a detailed view of the cam  22  of  FIG. 1 , showing a side view opposite the side illustrated in  FIG. 1 , wherein loop  24   a  of bow string  24  appears on left hand side of  FIG. 2 . The cam  22  includes a hub  23 , which is rotatably mounted on axle  32  extending between forks  17   a  and  17   b . The hub  23  is located at an eccentric position within cam  22 , so as to provide eccentricity as the cam  22  is rotated. 
     The cam  22  consists of a structure having an irregular generally disc-shaped body rotatable about an axle  32 . The rim of the disc-shaped body is configured to provide a cam surface around a portion of its perimeter. The cam  22  includes one or more tracks  34 ,  38 ,  40  that each provide a cam surface that receives a corresponding bow string or cable, for progressively retracting and releasing the bow string  24  or power cable  26 . Each track comprises a groove  35 ,  39 ,  41  for receiving either the bow string  24  or a power cable  26 . Track  34  receives the bow string  24  within the groove  35 . Track  34  extends substantially around the periphery of cam  22  and thus has essentially the same configuration as the periphery of cam  22 . End loop  24   a  of the bow string  24  is attached to the cam  22  at a string anchor  36 , located near the middle of cam  22 . The second end loop  24   b  of the bow string  24  is routed around second track  38  and groove  39  and also is attached to the string anchor  36 . Power cable  26  is routed around a third track  40  and groove  41  and is attached to the cam  22  at a cable anchor  42 . 
     Both ends of the bow string  24  engage the cam  22  adjacent circumferential locations of the tracks  34 ,  38 . Power cable  26  engages cam  22  at a circumferential location generally opposed to the location where the bow string engages cam  22 . As a result, tensioning of power cable  26  rotates cam  22  so as to tighten bow string  24  and vice versa. 
     When the bow  10  is in a static, tensioned configuration, wherein bow  10  is ready for use and the bow string  24  is not drawn, the cam  22  remains in a static position wherein respective rotationary forces of the bow string  24  and the power cable  26  balance each other. As the bow string  24  is drawn, cam  22  rotates in a first direction and the power cable  26  is wound around the track  40  and groove  41 , thereby drawing the limbs  16 ,  17  of the bow  10  together. When the bow string  24  is released, the cam  22  rotates in an opposite, second direction from the first direction, releasing tension on the power cable  26  and wrapping the bow string  24  around tracks  34 ,  38 . Cam  22  rotates back to the static position. During use, the cam  22  rotates approximately 180 to 270 degrees, depending on the type of bow and the draw length of the user. 
     Performing maintenance on the bow  10 , cam  22 , bow string  24  or power cable  26  typically requires reducing or removing the tension on the bow string  24  or the power cable  26 . By rotating the cam  22  in either a clockwise or counter-clockwise direction, and preventing rotation of the cam  22  back to the static position, tension in the bow string  24  or the power cable  26  is reduced or removed. To prevent rotation of the cam  22 , a cam stop is provided. It will be seen that various types of cam stops may be employed, which serve to selectively prevent the cam from rotating and returning to its original static position. Depending on the type of cam stop used it may prevent the cam from rotating in either a clockwise or counterclockwise direction or the cam stop may prevent rotation of the cam  22  in both clockwise and counterclockwise directions. In the described embodiment, the cam stop comprises one or more apertures  44  within the cam  22  for receiving a removable member  28 . Apertures  44  extend in a linear array adjacent to the periphery of cam  22 . The array is curved to match the periphery of cam  22  and is sufficiently long to provide a range of cam stop positions, in order to accommodate various configurations and tensions on the respective string and cables. The apertures  44  are spaced reasonably close together, but with sufficient spacing to ensure robustness of the cam  22 . For example, in one embodiment, the series of apertures  44  comprises 8 apertures extending across a span approximately 1.5 inches long at the periphery of the cam  22 ; the apertures  44  are approximately 3/16 inches in diameter and spaced apart ¼ inch from center to center. 
     Apertures  44  are located on cam  22  so as to be adjacent to forks  17   a ,  17   b  when the bow is in its normal tensioned configuration. The array of apertures  44   a - 44   g  allows for a range of circumferential or stop positions of cam  22  as described below. Member  28  is preferably cylindrical to match apertures  44 , but may alternatively have other configurations. Member  28  fits snugly within aperture  44  so as to prevent inadvertent slippage, but can still be readily removed without undue difficulty, even in adverse conditions. Member  28  protrudes outwardly in a lateral direction from one and preferable both sides of cam  22  when properly inserted, so as to contact one or both of forks  17   a  and  17   b  when cam  22  is rotated. Member  28  is thus brought into contact with the forks  17   a ,  17   b  as cam  22  rotates in the direction of the forks  17   a ,  17   b . When thus engaging one or both of forks  17   a ,  17   b , member  28  prevents further rotation of the cam  22  in the direction of contact. 
     In order to use the cam stop to detension the bow string  24 , a user holds the bow  10  in a position for maintenance. For example, by holding the riser  12 , the user may hold the bow string  24  with their foot and pull on the riser  12  slightly in order to initiate rotation of the cam  22 . For the purposes of illustration, and with reference to  FIG. 2 , the cam  22  is rotated in a clockwise direction in this step. The cam stop is then actuated to prevent back-rotation of cam  22  in the counter-clockwise direction. This is accomplished by inserting member  28  into an appropriate aperture  44  which is closest to the forks  17   a  and  17   b  so as to minimize the back-rotation of cam  22  when the bow string  24  is released. Upon insertion of member  28 , the bow string  24  is released, thereby permitting a small amount of back-rotation of cam  22  until member  28  engages and bears on forks  17   a  and  17   b , thereby stopping the cam  22  in a circumferential position, preventing further rotation and countering the tension applied by power cable  26 . Member  28  is firmly retained within the aperture  44  by its engagement of the limb  17 . Member  28  is thus urged against the forks  17   a ,  17   b  by the tension of cable  26  acting on cam  22 . At this stage, the bow string  24  is detensioned and maintenance or other work may be performed on the bow string  24 . Typically, the bow string  24  is pulled a few inches and the cam  22  rotated a few degrees before actuating the cam stop in order to relax tension on the bow string  24 . 
     To remove the member  28  and return the cam  22  to a static position, the bow string  24  is pulled slightly to initiate clockwise rotation of the cam  22  and release the member  28  from being urged against the limb  17  or forks  17   a ,  17   b . With the bow string  24  and cam  22  held in this position, the member  28  can be removed from the aperture  44 . The bow string  24  can be gently released to allow the cam  22  to rotate back to the static position. 
     In one embodiment, member  28  is a cylindrical pin approximately 1.5 inches long and is comprised of hardened stainless steel. It will be appreciated that the dimensions and configuration of member  28  may be varied depending on the configuration, spacing and dimensions of the cam  22 , limb  17 , forks  17   a ,  17   b  and apertures  44 . Further, member  28  and aperture  44  are illustrated as a cylindrical pin and corresponding circular hole. It will be appreciated that members and corresponding apertures of other configurations may be provided. Since member  28  is urged against the limb  17  and forks  17   a ,  17   b , the aperture  44  may be sized somewhat larger than the member  28 . Alternatively, member  28  may be curved to hook onto the forks  17   a ,  17   b . In another embodiment, member  28  may be non-removable from cam  22 , such as a releasable spring-loaded pin that can be moved between extended and retracted positions. 
     In a preferred embodiment, member  28  is dimensioned to engage both of the forks  17   a ,  17   b  of the limb  17  of a solid limb bow. Similarly, for a bow  10  having a split limb  17 ′ as shown in  FIG. 5A , member  28  may be dimensioned to engage both limbs  17 ′ a  and  17 ′ b.    
     To relax tension on the power cable  26  on the single cam bow  10  in  FIG. 2 , the power cable  26  is pulled to rotate the cam  22  in the direction of the power cable  26 . A user holds the bow  10  in a position for maintenance, such as by holding the riser  12 . For example, the user may pull the power cable  26  away from the riser  12  to initiate rotation of the cam  22 . For the purposes of illustration, and with reference to  FIG. 2 , the cam  22  rotates in a counter-clockwise direction. With the power cable  26  and cam  22  held in this position, the member  28  is inserted into an aperture  44   d  appearing adjacent or above the forks  17   a ,  17   b . The power cable  26  is released slowly, allowing cam  22  to rotate slightly in a clockwise direction. As the cam  22  rotates back, the member  28  is urged against the forks  17   a ,  17   b  thereby stopping the cam  22  in a circumferential position. Cam  22  is prevented from rotating further in the clockwise direction back to the static position. At this stage, the power cable  26  is relaxed and maintenance or other work may be performed on the power cable  26 . Typically, the power cable  26  is pulled a few inches and the cam  22  rotated a few degrees in order to relax tension on the power cable  26 . 
     Upon insertion of member  28 , the bow string  24  is released, thereby permitting a small amount of back-rotation of cam  22  until member  28  engages and bears on forks  17   a  and  b , thereby stopping the cam  22  in a first circumferential position, preventing further rotation and countering the tension applied by power cable  26 . 
     It will be appreciated that in performing work on either the bow string  24  or power cable  26 , moderate rotation and release of the cam  22  are used to ensure the bow string  24  and power cable  26  remains in the appropriate tracks  34 ,  38 ,  40  and grooves  35 ,  39 ,  41  in the cam  22 . 
       FIG. 3  illustrates a dual cam bow  50  having a riser  12  and integral carrying handle  14 . Upper and lower limbs  16  and  17  extend from opposing ends of the riser  12 . The limbs  16 ,  17  terminate at their distal ends in spaced forks  16   a ,  16   b  and  17   a ,  17   b  respectively. An upper cam  52  is mounted to the limb  16  at the top of the bow  10  on an axle  53  which span the forks  16   a ,  16   b . A lower cam  54  is mounted to the limb  17  on an axle  55  which spans the forks  17   a ,  17   b . The upper cam  52  and lower cam  54  typically are mounted in a mirror image fashion. A bow string  60  and first and second power cables  62 ,  64  are mounted and routed between the cams  52 ,  54  in a conventional manner. 
     A detailed view of the lower cam  54  of the dual cam bow  50  is illustrated in  FIG. 4 . The cam  54  of the dual cam bow  50  typically includes two tracks  70 ,  72 . Each track  70 ,  72  has a corresponding groove  71 ,  73  respectively for receiving the bow string  60  and one of the power cables  62 ,  64 . The grooves form cam surfaces for receiving the bow string  60  or power cables  62 ,  64 . The bow string  60  is routed around the track  70  in the groove  71  and is attached at a string anchor  76 . The second end of the bow string  60  is routed around and attached at the upper cam  52  in a similar fashion. The first power cable  62  is routed around the track  72  in groove  73  and is attached at a cable anchor  78 . The second power cable  64  is attached to the lower cam  54  at the axle  55  and is routed to the upper cam  52 . 
     The first and second power cables  62 ,  64  are routed and attached at the upper cam  52  in complementary fashion. The first power cable  62  is attached at the axle  53  of the upper cam  52 . The second power cable  64  is routed around a second track and groove in the cam  52  and attached a cable anchor on the cam  52 . The upper cam  52  includes a similar cam stop as described below for the lower cam  54 , although configured as a mirror image thereof. 
     One or more apertures  80  for receiving the member  28  are located in the cam  54 . The apertures  80  are located adjacent to the paths of the forks  17   a ,  17   b  over the cam  54 . As described above, the apertures  80  may include a series of apertures  80   a - 80   h  located adjacent to the periphery of the first track  70  of the cam  54 . The apertures  80  may be circular for receiving a cylindrical member  28 , but a number of shapes and configurations may be used. 
     In order to relax tension in the bow string  60  and one of the power cables  62 ,  64 , the cam  54  may be rotated slightly and held in this circumferential position by actuation of the cam stop. As illustrated in  FIG. 5 , the cam stop may comprise a member  28  inserted through an aperture  80  in the track  70 . The member  28  is urged against the forks  17   a ,  17   b  of the limb  17 , thus preventing rotation of the cam  54  back to a static position. Member  28  is firmly retained within the aperture  80  by its engagement of the limb  17  member  28  is urged against the forks  17   a ,  17   b  by the tension of the one of the power cables  62 ,  64 . 
     When working on the dual cam bow  50 , tension in the bow string  60  and one of the two power cables  62 ,  64  may be relaxed at the same time, with the other power cable maintaining tension between the limbs  16 ,  17  of the bow  50 . Tension in the bow string  60  may be relaxed by locking either the upper cam  52  or lower cam  54 . Tension in the first power cable  62  may be relaxed by locking the upper cam  52  and tension in the second power cable  64  may be relaxed by locking the lower cam  54 . 
     With reference to the cam  54  illustrated in  FIG. 4 , to relax tension on the bow string  60  and the second power cable  64  of the dual cam bow  50 , a user holds the bow  50  in a position for maintenance, such as by holding the riser  14 . The bow string  60  is pulled to rotate the cam  54  in the direction of the bow string  60 . For the purposes of illustration, and with reference to  FIG. 4 , the cam  54  is forced to rotate in a counter-clockwise direction. With the bow string  60  and cam  54  held in this position, the cam stop is actuated. For example, the member  28  is then inserted into an aperture, such as aperture  80   e , appearing adjacent to the forks  17   a  and  17   b . The bow string  60  is slowly released, allowing the cam  54  to rotate back slightly in a clockwise direction. As the cam  54  rotates back, member  28  is urged against the forks  17   a ,  17   b  thereby stopping the cam  54  in a circumferential position. The cam  54  is prevented from rotating back to a static position. At this stage, both the bow string  60  and second power cable  64  are relaxed. Tension between the limbs  16 ,  17  of the bow  50  is maintained by the first power cable  62 , and maintenance or other work may be performed on the bow string  60  and second power cable  64 . Typically, the bow string  60  is pulled a few inches and the cam  54  rotated a few degrees in order to relax tension on the bow string  60  and the second power cable  64 . 
     To remove member  28  and return the cam  54  to a static position, the bow string  60  is pulled slightly to initiate counter-clockwise rotation of the cam  54 . With the bow string  60  and cam  54  held in this position, the member  28  is then removed. The bow string  60  can be gently released to allow the cam  54  to rotate in a clockwise direction and return to a static position. 
     To relax tension in the first power cable  62 , and again in the bow string  60 , a similar procedure is performed with the bow string  60  and the upper cam  52 . In this configuration, the bow string  60  and first power cable  62  are relaxed. Tension between the limbs  16 ,  17  of the bow  50  is maintained by the second power cable  64 . 
     As illustrated in  FIG. 4 , locking of the cam  54  against rotation allows other maintenance to be performed on the bow  50  or cam  54 . A shooting module (not shown) may be mounted to a side of the cam  54  at module attachment points  90 . For example, a module may be screwed or bolted to the attachment points  90 . With the cam  54  in a static position, the attachment points  90  may be blocked by the forks  17   a ,  17   b  of the limb  17  of the bow  50 , thus preventing easy replacement or tightening of the module. Rotation and locking of the cam  54  as described above may be performed to move the attachment points  90  away from the forks  17   a ,  17   b  and enable clear access to the attachment points  90 . 
     As illustrated in  FIG. 1  and in the close-up view of  FIG. 6 , the member  28  may be attached to the bow  10  for storage when not in use. The member  28  may be retained in slot  94  in the riser  14  or clipped or otherwise attached to the bow  10 ,  50 . In one embodiment, the member  28  may have the same dimensions and construction as an axle  32 ,  53 ,  55  for the bow  10 ,  50  so that the member  28  may be used as a replacement axle if repairs are needed when the bow is in use. 
     It will be appreciated that a similar cam and cam stop, lock or anti-rotation mechanism may be applied for other compound bow configurations such as a cam and a half bow, compound cross-bow or a binary cam bow. For a cam and a half bow, the bow string may comprise two portions with a first portion routed from the cam on the lower limb and terminated at the wheel and a second portion routed from the wheel and terminated at the cam. In this configuration a cam and cam stop may be used on the cam on the lower limb in order to relax the tension on the bow string or the power cable. In another embodiment of the cam and a half bow, a lock may be provided on the wheel on the upper limb to lock the wheel in a rotated position and relax tension on the bow string only. 
       FIG. 7  illustrates alternative cam stop mechanisms. For example, an aperture  95  may be non-circular; for example, it may be triangular for receiving a similarly triangular shaped member (not shown). An aperture  96  may be irregular in shape and include a notched portion  97  for engaging member (not shown). An aperture may be defined by portions of the cam such as spokes  98 . Alternatively, an aperture  99  also may be provided through the forks  17   a  and  17   b  and aligned with an aperture in the cam  22 . The apertures in the cam  22  and forks  17   a ,  17   b  thus receive the member  28  to block rotation of the cam  22  in any direction. 
     The cam stop also may be provided with a first portion for engaging one fork of a bifurcated limb and second portion for engaging the other fork of the limb. Alternatively, a cam stop may be provided on the forks of the limb to engage a portion of the cam and lock the cam in a selected rotational position. For example, one or more locks or hooks may be provided on the limb or on the forks to engage an aperture or corresponding lock or hook on the cam. 
       FIGS. 8 and 9  illustrate an alternative embodiment of the present disclosure. The cam  100  consists of a structure having an irregular generally disc-shaped body which is rotatably mounted on axle  32  extending between the forks  110   a  and  110   b  of the limb  110 . The cam has one or more tracks  34 ,  38 ,  40 , and grooves  35 ,  39 ,  41  for receiving either the bow string  24  or a power cable  26  as described above in respect of  FIG. 2 . The routing and mounting of the second end loop  24   b  and power cable  26  are not shown in  FIG. 8 . 
     A cam stop  112  is provided consisting of a ratchet  114  including a pawl  115  mounted on the limb  110  and a corresponding rack  116  located on the cam  100 . In one embodiment, the pawl  115  is mounted on a bottom side  111  of one of the forks  110   b  with the pawl  115  facing the cam  100  and rack  116 . The rack  116  is located along an outer periphery of the cam  100 , such as on one or both sides of the track  34 . The rack  116  protrudes outwardly in a lateral direction from the cam  100 . The ratchet  114  prevents rotation of the cam  100  in a first direction. A second ratchet (not shown) may be mounted on a top side  113  of the fork  110   b  to engage the rack  116 . The second ratchet may be set to prevent rotation of the cam  100  in a second direction, opposite the first direction. Alternatively, a second ratchet (not shown) may be mounted on the fork  110   a  and engage a second rack (not shown), similar to the rack  116 , on the opposite side of the cam  100 . 
     In a further alternative embodiment, a ratchet  120  may be provided between the forks  110   a  and  110   b  and facing the track  34  of the cam  100 . As shown in  FIG. 9 , the pawl  121  of the ratchet  120  may be mounted on the center of the limb  110  at the base of the forks  110   a  and  110   b  for engaging a second rack  122  on the cam  100 . The rack  122  is located along an outer periphery of the cam  100 , such as on the track  34 , and the teeth of the rack protrude radially outward from the cam  100 , the teeth of the rack facing the pawl  121 . 
     As best seen in  FIG. 9 , the ratchet  120  comprises a pawl  121  which may be rotatable about a pivot  124  so as to selectively engage the pawl  121  with the rack  122  to lock the cam  100 . The pawl  121  may be rotated away from the cam  100  when the cam  100  and bow are in operation. A spring  126  may be provided to bias the pawl  121  away from the cam  100  during normal operation. Alternatively, the ratchet  120  may be slidably mounted on the limb  110  and moved into a position to engage the rack  122  on the cam  110 . A similar spring (not shown) or slidable engagement mechanism may be provided on the ratchet  114 . 
     With reference to the ratchet  120  illustrated in  FIG. 9 , to perform maintenance on the bow, a user holds the bow  10  in a position for maintenance and the cam  100  is rotated in a first direction as described above. The ratchet  120  is actuated so that the pawl  121  engages the rack  122  to prevent rotation of the cam  100  back to the static position, thereby removing tension in the bow string  24  or the power cable  26 . Once maintenance is complete, the ratchet  120  may be de-actuated or released to allow the cam  100  to rotate back to a static position. A second cam stop (not shown) may be provided and actuated to prevent rotation of the cam  100  in the opposite direction. 
     While this invention has been described in conjunction with specific embodiments thereof, it is evident that the invention is not limited to these specific embodiments. Rather, numerous alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description, as well as the present specification as a whole including the claims. Accordingly, the purpose and intention of the inventors is to embrace and include all reasonably foreseeable alternatives, modifications and variations as fall within the broad scope of the invention as described and claimed herein.