Abstract:
An archery bow comprising a riser extending between opposing first and second ends. A limb is coupled to each end of the riser. Each limb has a first end for connecting to the riser and a second distal end. A pocket axle pivotally connects the first ends of each limb to one end of the riser. A strut assembly is operatively coupled between each of the limbs and the riser adjacent the pocket axle for selectively pivoting the limbs relative to the riser thereby allowing manual assembly and tuning of the bow by varying the distance between the distal ends of the limbs.

Description:
This application claims the benefit of provisional application No. 60/325,376 filed Sep. 27, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to archery bow assemblies, and more particularly, to a strut assembly for mounting the limbs of the bow to the riser. 
     2. Description of the Related Art 
     Archery bows typically include a riser defining a handle for holding the bow and a pair of limbs extending from opposite ends of the riser to distal ends. A wheel or cam is commonly rotatably attached to the distal end of each limb and a string and harness system is wound between the wheels or cams of the limbs. The limbs are often flexed and the string and harness system is loaded under high tension to define the draw weight or force required to pull the string of the bow to its full draw position. 
     It is often desirable to change the string of the bow due to excessive wear or to change the draw weight of the bow. To change the string or other component of the bow typically requires the use of a bow press to flex the limbs of the bow and release the tension on the string and harness allowing removal from the wheels or cams. The bow press may then be used to release the flex on the limbs for complete disassembly of the bow. 
     The draw weight of the bow may be changed by attaching a different length string between the wheels or cams or by change the angle or orientation of the limbs relative to the bow. It is common to connect the limbs of the bow to the riser with a bolt or connector which extends through the limb and is threaded into the riser. The connector may be loosened to change the orientation of the limbs on the riser and slightly adjust the draw weight of the bow. However, significant shearing forces are exerted on the connector as the orientation of the limbs relative to the riser is changed. Additionally, the connector does not allow the bow to be assembled or disassembled without the use of a bow press. 
     Therefore, it remains desirable to provide a bow which may be manually assembled and disassembled without the need of a bow press and also an assembly which provide for full adjustment of the draw weight and tuning of the bow. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention there is provided an archery bow comprising a riser extending between opposing first and second ends. A limb is coupled to each end of the riser. Each limb has a first end for connecting to the riser and a second distal end. An axle pivotally connects at least one of the limbs to one end of the riser. A strut assembly is operatively coupled between at least one of the limbs and the riser adjacent the axle for selectively pivoting the limb relative to the riser thereby allowing manual assembly and tuning of the bow by varying the distance between the distal ends of the limbs. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
     FIG. 1 is a side view of an archery bow assembly according to one aspect of the invention; 
     FIG. 2 is a fragmentary exploded view of the archery bow assembly and strut assembly for attaching the limbs to the riser; 
     FIG. 3 is an enlarged perspective view of the strut assembly connected between the limb and the riser; 
     FIG. 4 is another enlarged perspective view of the strut assembly connected between the limb and the riser with a portion of the limb removed; and 
     FIG. 5 is a cross-sectional view of the strut assembly between the limb and riser. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, FIG. 1 illustrates a compound archery bow  10  having a riser  12  with a pair of limbs  14 ,  16  extending from opposing ends  18 ,  20  of the riser  12 . The limb  14  has a first end  22  connected to the end  18  of the riser  12  and a second distal end  24 . Similarly, the limb  16  has a first end  26  connected to the opposite end  20  of the riser  12  and a second distal end  28 . A wheel or cam  30 ,  32  is rotatably attached to each distal end  24 ,  28  of the limbs  14 ,  16 . Additionally, a harness or cable system  34  and bow string  36  are wound around and between each wheel or cam  30 ,  32  and pulled in tension by the limbs  14 ,  16 . 
     The bow  10  further includes a pair of limb pockets  38 ,  40  for pivotally attaching the respective limbs  14 ,  16  to the opposing ends  18 ,  20  of the riser  12 . A pocket axle  42  pivotally couples each of the respective limbs pockets  38 ,  40  to the opposing ends  18 ,  20 . Finally, a strut assembly  44  adjustably couples each of the limb pockets  38 ,  40  to the opposing ends  18 ,  20  of the riser. The strut assembly  44  allows for assembly and disassembly of the limbs  14 ,  16  and limb pockets  38 ,  40  to the riser  12  as well as the harness system  34  and string  36  between the wheels or cams  30 ,  32 . Additionally, the strut assembly  44  further allows for selective micro-tuning and adjustment of the bow  10 , such as for example, the adjustment of the bow&#39;s draw weight and/or axle to axle length between the wheels or cams  30 ,  32 . 
     More specifically, referring to FIGS. 2-5, the strut assembly  44  is shown in more detail. Only one strut assembly  44  between the limb  14  and riser  12  will be described in detail, however, it should be appreciated that the strut assembly  44  between the opposite limb  16  and riser  12  includes the same elements and function. The strut assembly  44  includes an adjustable threaded strut power screw  46  coupled to and between the limb pocket  38  and the end  18  of the riser  12 . Referring more particularly to FIG. 2, the end  18  of the riser  12  includes an extended pair of spaced apart fingers  48 ,  50  each having a bore  52  therethrough for receiving the pocket axle  42  and pivotally securing the limb pocket  38  to the riser  12 . The limb pocket  38  includes a base  54  having a pivot post  56  extending therefrom with a through bore  58 . The pivot post  56  is seated between the fingers  48 ,  50  and the bores  52 ,  58  aligned axially to receive the pocket axle  42  therethrough. A spacer  60  is received on each side of the pivot post  56  around the axle  42  and an end cap or bushing  62  is secured to the distal end of the pocket axle  42  to pivotally secure the limb pocket  38  to the riser  12  while allowing pivotal movement of the limb  14  and limb pocket  38  about the pocket axle  42  and end  18  of the riser  12 . 
     Each limb  14 ,  16  may be a single unitary member, may be two spaced apart members or may be a split limb, as shown in FIG. 2, with a pair of substantially separate and parallel spaced apart limb posts  64  connected to a main member  66 . The base  54  of the limb pocket  38  includes spaced apart tunnels  68  for receiving and mounting the limb posts  64  to the limb pocket  38  along the longitudinal length thereof. The limb posts  64  may be secured to the limb pocket  38  by any suitable means. 
     The limb pocket  38  further includes a pair of spaced apart support posts  70 ,  72  extending longitudinally from the base  54  and attached by an end cap  74 . Each support post  70 ,  72  includes a bore  76  therethrough, the axis of which is parallel to the pocket axle  42 . A cylindrical strut pivoting power screw nut  78  is seated in each bore  76  between the spaced apart and parallel support posts  70 ,  72 . The screw nut  78  includes a longitudinal bore  80  extending therethrough and a transverse bore  82  extending perpendicular to the bore  80  for receiving the strut power screw  46 . Each of the bores  80 ,  82  are threaded and the screw nut  78  is freely rotatably seated in the bores  76  of the support posts  70 ,  72 . The power screw  46  is threaded through the bore  82  toward the riser  12  and retained in the limb pocket  38  by the screw nut  78 . 
     A ball plunger  84  is threaded into the bore  80  as shown in FIGS. 2 and 5. The ball plunger  84  includes a compression spring  86  seated between a cap  88  and ball bearing  90 . The ball plunger  84  is biased against the power screw  46  for indexing the rotational position of the power screw  46  relative to the screw nut  78  as will be further described hereinbelow. 
     The strut power screw  46  is a cylindrical threaded rod extending longitudinally between a first nut end  92  and a second distal end  94  having a concave recess  96  therein. The power screw  46  further includes a row of spaced apart indexing holes or recesses  98  extending along the longitudinal extent of the screw  46  for engagement with the ball plunger  84 . The power screw  46  may include one or more rows of indexing holes  98  around the perimeter of the screw  46  at any number of spaced apart degrees of separation with the individual holes  98  spaced apart longitudinally as desired. For example, the screw may include two parallel rows of indexing holes  98  spaced apart 180 degrees; three rows spaced apart 120 degree; four row spaced apart 90, etc. 
     Once the strut power screw  46  is threaded through the screw nut  78 , the nut end  92  is seated between the support posts  70 ,  72 . The second distal end  94  extends towards the end  18  of the riser  12  through a first strut shock absorber washer  100 , a cylindrical resilient strut shock absorber  102  (which is corrogated as shown) and a second strut shock absorber washer  104 . 
     Still referring to FIGS. 2 and 5, the riser  12  further includes spaced apart flanges  106 ,  108  each having a hole  110  therethrough with the axes of which are parallel to the axis of the pocket axle  42 . A cylindrical strut power screw ball bearing retainer  112  is rotatably seated between the flanges  106 ,  108  and aligned axially with the holes  110 . The retainer  112  includes an axial bore  114  aligned with the holes  110  and a transverse bore  116  extending perpendicular to and through the axial bore  114  for receiving the distal end  94  of the power screw  46 . 
     Finally, the strut assembly  44  includes a cylindrical strut pivot support  118  dimensioned to be rotatably received in the axial bore  114  of the retainer  112  and holes  110  of the riser flanges  106 ,  108 . The strut pivot support  118  includes a recessed detent  120  in the periphery outer wall thereof for seating and supporting a ball bearing  122 . The second distal end  94  of the power screw  46  is inserted through the transverse bore  116  in the ball bearing retainer  112  and the ball bearing  122  is rotatably seated between the recess  96  in the end of the power screw  46  and the detent  120  in the pivot support  118  to facilitate rotation of the strut power screw  46 . 
     The strut assembly  44  enables the end user of the archery bow  10  to assemble, disassembly and micro-tune or selectively adjust the characteristics of the bow  10  without the necessity of a conventional bow press typically used to compress the bow limbs and allow removal of the cables and string. More specifically, once the limbs  14 ,  16  are secured to the limb pockets  38 ,  40 , the limb pockets  38 ,  40  may be pivotally attached to the opposing ends  18 ,  20  of the riser  12 . The strut assembly  44  is then coupled between the limb pockets  38 ,  40  and each end  18 ,  20  of the riser  12 . Next, the wheels or cams  30 ,  32  may be assembled to the distal ends of the limbs  14 ,  16  and then the harness or cable system  34  and string  36  are attached to the wheels or cams  30 ,  32 . The strut assembly  44  allows the limbs  14 ,  16  to be pivoted toward the riser  12  to reduce the distance between the distal ends of the limbs  14 ,  16  for attachment of the harness  34  and string  36  without tension. Once assembled, the nut end  92  of the strut power screw  46  may be rotated using a ratchet or wrench in a clockwise direction as shown in the drawings to increase the angle between the limbs  14 ,  16  and riser  12  until the limbs  14 ,  16  start to flex naturally due to the fixed length of the string  36  and harness  34  coupled between the wheels  30 ,  32 . Rotating the strut power screw  46  forces the power screw nut  78  to travel longitudinally along the threaded length of the screw  46  and pivot the limb pocket  38 ,  40  about the pocket axle  42  and riser  12 . As the strut power screw  46  is rotated and the limbs  14 ,  16  flex and pivot open relative to the riser  12 , the distance between the wheels or cams  30 ,  32  increases and the harness  34  and string  36  is pulled in tension to a desired draw weight. Additionally, the strut shock absorber  102  which encases and protects the strut power screw  46  may be compressed between the limb pockets  38 ,  40  and riser  12  to allow pivotal movement of the limbs  14 ,  16  while preventing dirt and debris from entering the strut assembly  44 . 
     In order to disassembly the bow  10 , the strut power screw  46  is simply rotated in the opposite, or counter-clockwise direction as shown, so that the screw nut  78  travels down the length of the screw  46  pivoting the limb pocket  38 ,  40  about the pocket axle  42  and riser  12  until the tension on the string  36  and harness  34  is loosened. The bow  10  may then be fully disassembled or part may be changed such as the string  36  without the need of a bow press to release the flex and tension on the limbs  14 ,  16  and string  36 . 
     Finally, the strut assembly  44  also allows selective adjustment of the bow  10  by rotation of the strut power screw  46  in either the clockwise or counterclockwise direction. As the screw nut  78  travels along the length of the threaded power screw  46  forcing the limb pocket  38 ,  40  to pivot about the riser  12 , the ball plunger  84  follows the outer perimeter of the power screw  46  and engages with each indexing holes  98  along the length of the power screw  46 . By counting or tracking the position of the ball plunger  84  relative to the indexing holes  98 , the bow  10  may be selectively adjusted by pivoting or tuning each limb  14 ,  16  position relative to the riser  12  to adjust the tension on the string  36  and the flex of the limbs  14 ,  16  which account for the draw weight of the bow  10  and also the axle to axle length defined between the wheels or cams  30 ,  32 . The location of the ball plunger  84  along the indexing holes  98  is maintain absent additional rotation of the power screw  46 . Therefore, by identifying the desired reference of the ball plunger  84  along the indexing holes  98 , the user may re-establish this adjustment after assembly and disassembly or after further tuning without having to go back to the factory recommended settings. Additionally, the user may selective adjust the bow  10  for different shooting conditions. For example, the strut assembly  44  allows the user to adjust the axle to axle distance to 37 inches during target practice and then adjust the axle to axle distance to 34 inches for hunting. The strut assembly  44  also allows the user to selectively adjust the bow draw weight infinitely by rotating the power screw  46  and pivoting the limbs  14 ,  16  relative to the riser  12 . 
     It should be appreciated to one skilled in the art that the strut assembly may be used on a recurve bow, compound bow or cross bow without varying from the invention. Additionally, the strut assembly may be coupled between only one of the limbs and the riser or both of the limbs and the riser. That is, one of the limbs may be fixedly attached to one end of the riser and the other limb pivotally attached to the opposite end of the riser with the strut assembly extending therebetween to selectively pivot the one limb relative to the riser sufficient to release the tension on the string and allow assembly, disassembly and tuning of the bow. 
     Finally, it should also be appreciated that the strut pivoting power screw nut  78  may be retained in the riser  12  and the strut pivot support  118  retained by the limb  14  or limb pocket  38  without varying from the scope of the invention or function of the strut assembly  44 . 
     The invention has been described in an illustrative manner, and it is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation. 
     Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practised other than as specifically described.