Patent Publication Number: US-6659096-B1

Title: Split-buss-cable single-cam compound archery bow

Description:
FIELD OF THE INVENTION 
     The field of the present invention relates to archery bows. In particular, a split-buss-cable single-cam archery bow is described herein including a splitter adjustable in position and width. 
     BACKGROUND 
     Solo or single-cam compound bows are well known in the art. A plurality of these have been previously disclosed, some of which are described in U.S. Pat. Nos. 5,505,185, 5,368,006, 5,975,067, and 6,098,607, each of said patents being incorporated by reference as if fully set forth herein. Dual-cam compound bows are also well known in the art, some of which are described in U.S. Pat. Nos. 4,739,744 and 5,040,520, each of said patents being incorporated by reference as if fully set forth herein. In these prior patents are described in detail the mechanics of a compound bow including non-circular single or dual cam members which impart dynamic forces on the bow limbs. 
     Whether single-cam or dual-cam, the purposes and advantages of compound bows are well known to those skilled in the art and need not be repeated herein. Compound bows typically comprise: a handle from which resilient bow limbs extend oppositely; pulley means comprising cams, levers, and/or pulleys and typically being disposed at the tips of the limbs of the bow; and one or more cables coupled to the bow limbs and/or pulley means to give assorted mechanical advantages. One important characteristic of compound bows is the “let-off” (i.e., an abrupt decrease) of the draw force at the end of the draw, thereby allowing an archer to more readily maintain the bow in a fully drawn position while accurately aiming the arrow and/or waiting for game to pass within shot. 
     A prior single-cam archery bow  1  is shown in FIGS. 1 and 2. Upper and lower bow limbs  11   a  and  11   b  are shown extending from central handle portion  10  and terminating at limb tips  12   a  and  12   b . Each limb tip is divided to accommodate a pulley assembly  20 / 30  and is provided with an axle for rotatably mounting each pulley assembly thereon. In a typical single cam bow, one pulley assembly (pulley assembly  20  in this example) comprises a substantially circular idler wheel substantially concentrically mounted on the corresponding axle. The other pulley assembly (pulley assembly  30  in this example) typically includes multiple cams, pulleys, and/or levers and is eccentrically mounted on the corresponding axle. A draw cable  40  is secured to pulley assembly  30  and passes around pulley assembly  20 , continuing as cable  41  (sometimes referred to as a let-out/take-up cable). Cable  41  is secured to pulley assembly  30 . A buss cable  45  (also referred to as a power cable) is secured to the axle of pulley assembly  20  and to pulley assembly  30 . As the bow is drawn, draw cable  40  is let out by pulley assembly  30 , while cable  41  is let out by pulley assembly  30  and passes around pulley assembly  20 . Buss cable  45  is taken up by pulley assembly  30 . The lengths of the cables and size, shape, and configuration of pulley assembly  30  determines the force vs. draw distance characteristics of the bow. 
     Bow  1  may typically be provided with a cable guard  50  and cable guard slide  52 . Cable  41  and buss cable  45  may pass through cable guard slide  52 , which in turn slides along cable guard  50 . The cable guard and slide serve to pull cables  41  and  45  laterally out of a draw/flight path of the arrow. An undesirable effect of cable guard  50  and slide  52  is the torque exerted on the pulley assemblies and bow limbs due to the lateral displacement of the cables, and the additional stress and wear on the cables themselves. These may degrade the accuracy and velocity of the bow, and may increase the frequency of string failure and replacement. One solution to this problem for a dual-cam compound bow is illustrated in U.S. Pat. No. 5,623,915 (hereinafter, “Kudlacek”), said patent being incorporated by reference as if fully set forth herein. The buss cables (two in the case of a dual-cam bow) are split after leaving the pulley assembly and the two split ends are secured to the two ends of the axle of the other pulley assembly (see FIGS. 1 and 2 of Kudlacek). A “splitter” holds apart the two split ends of the cable, preferably in a substantially parallel arrangement. The arrow may pass unimpeded between the split portions of the buss cables, and the substantially parallel arrangement and substantially symmetric attachment of the split ends to the axle substantially eliminates torque exerted on the bow by the buss cables as the bow is drawn. The location of the splitter is typically fixed along the length of the buss cables, and the width of the split buss cables often results in interference between the buss cables and the archer&#39;s arm as the bow is drawn and released. 
     It is desirable to provide a split buss cable and splitter adapted for use with a single-cam compound bow. It is desirable to provide a splitter that may be readily moved along the length of the buss cable and secured at varying locations thereof. It is desirable to provide a splitter having an adjustable width enabling its use with a variety of compound bows and bowstrings. It is desirable to position the splitter along the length of the buss cable so as to reduce interference between the buss cable and an archer&#39;s arm as the bow is drawn and released. 
     SUMMARY 
     Certain aspects of the present invention may overcome one or more aforementioned drawbacks of the previous art and/or advance the state-of-the-art of compound archery bows, and in addition may meet one or more of the following objects: 
     To provide a single-cam compound archery bow including a split-buss-cable; 
     To provide a single-cam compound archery bow including a split-buss-cable for reducing torque on the bow as it is drawn; 
     To provide a single-cam compound archery bow including a split-buss-cable for improving the accuracy and/or velocity of the bow; 
     To provide a single-cam compound archery bow including a split-buss-cable for reducing stress and wear on the buss cable; 
     To provide a single-cam compound archery bow including a split-buss-cable and an adjustable-width splitter; 
     To provide a single-cam compound archery bow including a split-buss-cable and an adjustable-position splitter; 
     To provide a single-cam compound archery bow including a split-buss-cable and a splitter positioned so as to reduce interference between the split buss cable and an archer&#39;s arm; 
     To provide an adjustable-width splitter for a split-buss-cable compound bow; 
     To provide a splitter than that may be used for a variety of different compound bows; 
     To provide an adjustable-position splitter for a split-buss-cable compound bow; 
     To provide a splitter for a split-buss-cable compound bow that may be positioned so as to reduce interference between the split buss cable and an archer&#39;s arm; 
     To provide a splitter for a split-buss-cable compound bow that does not require any splitter component to be tied directly into the buss cable; 
     To provide a splitter and a pre-stretched split buss cable for a compound bow, thereby reducing movement and/or misalignment of the splitter as the bow is used; and 
     To provide a splitter for a split-buss-cable compound bow that is adapted for tethering a fall-away arrow rest thereto. 
     One or more of the foregoing objects may be achieved in the present invention by a compound archery bow, comprising: a central handle portion; a first flexible bow limb and a second flexible bow limb terminating in first and second bow limb tips, respectively; a substantially circular pulley wheel rotatably mounted at the first bow limb tip; a cam assembly rotatably mounted eccentrically at the second bow limb tip; a draw cable secured to the cam assembly and passing around the pulley wheel; a let-out/take-up cable secured to the cam assembly and passing around the pulley wheel; a split buss cable having a first end secured to the cam assembly and a second end bifurcated into first and second split buss cable ends, each being secured at the first bow limb tip in a substantially bilaterally symmetric configuration; and a buss cable splitter including a substantially rigid member secured to the first and second split buss cable ends so as to hold the first and second split buss cable ends in a spaced-apart configuration separated by a splitter distance, the cam assembly being adapted for letting out the draw cable as the bow is drawn, for letting out the let-out/take-up cable as the bow is drawn, and taking up the first end of the split buss cable as the bow is drawn. 
     One or more of the foregoing objects may be achieved in the present invention by a buss cable splitter, comprising: a first cable clamp adapted for securing the splitter to a first split cable end of a split buss cable; a second cable clamp adapted for securing the splitter to a second split cable end of the split buss cable; and a substantially rigid central member connected to the first and second cable clamps, the central member being adapted for holding in a spaced-apart configuration the first and second split cable ends of the split buss cable when said first and second split buss cable ends are clamped within the first and second cable clamps, respectively. The clamps may each include a main clamp member secured to the central member and a secondary clamp member urged toward and secured to the main clamp member by a clamp fastener, with the split buss cable ends being clamped between the corresponding main clamp members and secondary clamp members. The length of the splitter, and hence a splitter distance, may be adjustable, preferably by providing the splitter including multiple threadedly engaged members. 
     The split buss cable reduces torque on the bow and stress and wear on the buss cable, and may increase the accuracy and/or velocity of the compound bow. The clamping arrangement of the splitter enables a variety of placements along the length of the split buss cable ends, and eliminates the need for directly tying the splitter into the buss cable, facilitating later adjustment of the splitter position. The splitter may also be positioned so as to reduce or eliminate interference between a split cable end and an archer&#39;s arm. Adjustable width of the splitter enables adjustment to achieve substantially parallel arrangement of the split buss cable ends, and use of the splitter with any of a variety of different compound bow types. 
    
    
     Additional objects and advantages of the present invention may become apparent upon referring to the preferred and alternative embodiments of the present invention as illustrated in the drawings and described in the following written description and/or claims. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1 and 2 are side and back views, respectively, of a prior single-cam compound archery bow. 
     FIGS. 3 and 4 are side and back views, respectively, of a single-cam compound archery bow according to the present invention. 
     FIGS. 5A,  5 B, and  5 C are top exploded, top assembled, and front assembled views, respectively, of a splitter according to the present invention. 
     FIGS. 6A,  6 B, and  6 C are top exploded, top assembled, and front assembled views, respectively, of a splitter according to the present invention. 
     FIGS. 7A,  7 B,  7 C, and  7 D are top views of alternative splitters according to the present invention. 
     FIGS. 8A and 8B are side views of a splitter, tether, and fall-away arrow rest according to the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED AND ALTERNATIVE EMBODIMENTS 
     FIGS. 3 and 4 show an exemplary embodiment of a single-cam compound archery bow  100  according to the present invention. Upper and lower bow limbs  111   a  and  111   b  are shown extending from central handle portion  110  and terminating at limb tips  112   a  and  112   b . Each limb tip is divided to accommodate a pulley assembly  120 / 130  and is provided with an axle for rotatably mounting each pulley assembly thereon. In this example of a single cam bow, one pulley assembly (pulley assembly  120  in this example) comprises a substantially circular idler wheel substantially concentrically mounted on the corresponding axle. The other pulley assembly (pulley assembly  130  in this example) may include multiple cams, pulleys, and/or levers and is eccentrically mounted on the corresponding axle. In the exemplary embodiment of FIGS. 3 and 4, pulley assembly  130  includes three eccentrically mounted cams. A draw cable  140  is secured to pulley assembly  130  and passes around pulley assembly  120 , continuing as cable  141  (also referred to as a let-out/take-up cable). Cable  141  is secured to pulley assembly  130 . A buss cable  145  (also referred to as a power cable) is secured to pulley assembly  130  at a first end, and splits into split buss cable ends  145   a  and  145   b  at the second end. Split buss cable ends  145   a  and  145   b  are secured to the axle of pulley assembly  120  on opposite sides of bow limb tip  112   a . A substantially rigid buss cable splitter  160  is secured to split buss cable ends  145   a  and  145   b  and employed to hold split buss cable ends  145   a  and  145   b  in a spaced-apart configuration. A cable guard  150  and cable guard slide  152  serve to pull cable  141  laterally out of the flight path of an arrow, with cable  141  passing through cable guard slide  152  and cable guard slide  152  sliding along cable guard  150 . One split buss cable end  145   b  may also pass through cable guard slide  152 , and preferably freely slides therethrough with little or no lateral displacement. The cable guard and slide serve to pull cable  141  laterally out of the flight path of an arrow. As the bow is drawn, draw cable  140  is let out by pulley assembly  30 , while cable  141  is let out by pulley assembly  130  and passes around pulley assembly  120 . Buss cable  145  is taken up by pulley assembly  130 . The lengths of the cables and size, shape, and configuration of pulley assembly  30  determines the force vs. draw distance characteristics of the bow, and may vary widely while remaining within the scope of inventive concepts disclosed and/or claimed herein. 
     The split arrangement of buss cable  145  and split buss cable ends  145   a  and  145   b  serve to keep the buss cable out of a flight path of an arrow, without undesirable torque being exerted on bow limb  111   a . This is achieved in part by securing the split buss cable ends  145   a  and  145   b  at opposite sides of bow limb tip  112   a  and pulley assembly  120 . Split buss cable ends  145   a  and  145   b  may preferably terminate in looped ends placed around opposite ends of an axle supporting pulley assembly  120 . Other suitable arrangements may be equivalently employed for securing the split buss cable ends, either directly or indirectly, to bow limb tip  112   a . This substantially symmetric attachment of spit buss cable ends  145   a  and  145   b  results in substantially reduced torque exerted on the bow as it is drawn, compared to bows having a non-split buss cable pulled to the side by the cable guard/slide. By making the first end (i.e., the non-split portion) of buss cable  145  sufficiently long, the splitter  160  and split buss cable end  145   a  may be positioned so as to substantially eliminate interference with the archer&#39;s arm as he/she draws and/or releases the bow. Splitter  160  is shown above a grip portion of central handle  110  in the exemplary embodiment of FIGS. 3 and 4. Preferably, the splitter position is chosen so that at substantially full draw of the bow the splitter does not reach the arm of the archer. Splitter  160  may preferably be constructed to enable removing and re-securing the splitter at varying positions along split buss cable ends  145   a  and  145   b . In this way various cable geometries may be employed for adjusting the performance of the compound bow. In previous splitter designs (for dual-cam compound bows), the splitter, or attachment hardware therefor, is tied directly into the split buss cable ends, thereby fixing the position of the splitter and preventing any subsequent adjustment of the compound bow. 
     To further reduce torque on the bow  100  as it is drawn, split buss cable ends  145   a  and  145   b  are preferably substantially parallel when held in a spaced-apart configuration by splitter  160 . A different splitter  160  may therefore be designed for each different compound bow so that the splitter width (alternatively, splitter distance) substantially matches the width of the attachments of split buss cable ends at the bow limb tip. Alternatively, the splitter may preferably be constructed so as to enable adjustment of the splitter distance. In this way, a single adjustable splitter may be used with a variety of compound bows having various widths for the attachment of the split buss cable ends. 
     A preferred embodiment for a splitter is shown in FIGS. 5A (top, exploded),  5 B (top, assembled), and  5 C (front). The splitter includes first and second cable clamps secured to a central member  166 . Each of the cable clamps preferably includes a main clamp member  162   a / 164   a  secured to the central member  166 , and a secondary clamp member  162   b / 164   b  secured to the corresponding main clamp member  162   a / 164   a  by at least one clamp fastener  162   c / 164   c . A split buss cable end may be clamped between a main clamp member and secondary clamp member urged together and secured together by clamp fastener(s). Threaded fasteners are shown, but any suitable fastener may be employed that enables removing and re-securing a split buss cable end between clamp members  162   a / 162   b  and /or  164   a / 164   b  while remaining within the scope of inventive concepts disclosed and/or claimed herein. Grooves  162   d / 164   d  may be provided for receiving the split buss cable ends  145   a / 145   b . The clamp arrangement enables removing and re-securing of splitter  160  at varying points along the lengths of split buss cable ends  145   a  and  145   b.    
     Main clamp members  162   a / 164   a  are shown threadedly engaged with central member  166 , thereby securing main clamp members  162   a / 164   a  to central member  166 . This threaded embodiment is preferred enabling adjustment of the splitter distance. Main clamp members  162   a / 164   a  may be threaded into central member  166  to varying degrees, thereby varying the splitter distance. The threads are preferably of opposite handedness for main clamp members  162   a /a 64   a  so that the splitter distance may be adjusted with the splitter already clamped onto the split buss cable ends. In an alternative embodiment, the threads may be of the same handedness, and adjustment of the splitter distance may be performed prior to clamping the splitter onto the split buss cable ends. In an alternative embodiment, central member  166  may be provided with one or more flat surfaces, one or more knurled surfaces, one or more holes, or other suitable structure(s) for facilitating adjustment of the splitter distance by hand or by using a wrench or other suitable tool. In an alternative embodiment, central member may be rigidly secured to one of main clamp members  162   a / 164   a  and threadedly engaged with the other. In an alternative embodiment, any other suitable mechanism for enabling adjustment of the splitter distance may be equivalently employed while remaining within the scope of inventive concepts disclosed and/or claimed herein. 
     In the embodiment of FIGS. 5A,  5 B, and  5 C, fasteners  162   c  and  164   c  urge clamp members  162   a / 162   b  and  164   a / 164   b , respectively, together in a direction substantially perpendicular to central member  166 . In an alternative embodiment shown in FIGS. 6A. 6B, and  6 C, clamp members are shown urged together by clam fasteners in a direction substantially parallel to central member  166 . In the embodiment of FIGS. 5A,  5 B, and  5 C, grooves  162   d / 164   d  are shown provided on main clamp members  162   a / 164   a  for receiving the split buss cable-ends. Grooves  162   d / 162   d  may alternatively be provided on secondary clamp members  162   b / 164   b  (alternative embodiment of FIG.  7 A), or on both main clamp members  162   a / 164   a  and secondary clamp members  162   b / 164   b  (alternative embodiments of FIGS. 6A,  6 B,  6 C, and  7 B). In an alternative embodiment shown in FIG. 7D, no grooves are provided. In an alternative embodiment shown in FIG. 7C, multiple grooves may be provided, enabling coarse adjustment of the splitter distance through the choice of groove for receiving a split buss cable end. Multiple grooves are shown in main clamp members  162   a / 164   a , but may alternatively be provided in secondary clamp members  162   b / 164   b , or in both main and secondary clamp members. In the alternative embodiment of FIG. 7B, only one fastener  162   c / 164   c  is shown for each cable clamp. Use of a single fastener or multiple fasteners may be employed in various of the embodiments disclosed herein as desired. 
     A groove or slot  169  may be provided on central member  166  for enabling attachment of a tether  170  for a fall-away arrow rest  180  (FIGS.  8 A and  8 B). Movement of the splitter during release of the arrow may therefore actuate the fall-away rest, allowing it to fall away from the arrow during the initial stage of the arrow&#39;s flight. 
     A split-buss-cable single-cam compound bow according to the present invention may preferably be constructed using pre-stretched cables. The use of pre-stretched cables reduces movement and/or mis-alignment of the splitter as the bow is repeatedly drawn and released during use. 
     It should be appreciated that an adjustable-width and/or adjustable-position splitter according to the present invention may be employed in constructing split-buss-cable dual-cam compound bows, in addition to the split-buss-cable single-cam compound bows of the present invention. Use of an adjustable-width and/or adjustable-position splitter in a dual-cam bow enables adjustment of cable configuration in a manner similar to that described hereinabove for a single-cam bow. 
     The present invention has been set forth in the forms of its preferred and alternative embodiments. These embodiments are illustrative and not intended to limit the scope of the claims set forth hereinbelow. It is intended that modifications to the disclosed split-buss-cable single-cam compound bow and/or adjustable-width/position splitter may be made without departing from inventive concepts disclosed and/or claimed herein.