Abstract:
The present invention is an improved compound bow. In particular the present invention is directed to an adjustable compound bow for hunting and archery with noise reduction features. The preferred embodiment of the bow comprises a riser having a main riser length with two ends, each end attached to an adjustable hub with a limb base. Each limb base preferably has a pocketless flat surface with vibration dampening material. Each hub is secured to the main riser length by an adjustment screw and a hub pivot. A limb is preferably secured to each limb base at two points on the pocketless flat surface. A bowstring is strung under tension between the limbs. The bowstring&#39;s tension can be adjusted by adjusting the adjustable hubs with the adjustment screws. The bow preferably has a storage position and an in-use position caused by rotating the limbs around the adjustable hubs. Adjustment of the bow can be accomplished without use of a bow press.

Description:
TECHNICAL FIELD 
   The present invention is an improved compound bow. In particular, the present invention is directed to an adjustable compound bow for hunting and archery with noise reduction features. 
   BACKGROUND ART 
   Generally, a compound bow is a bow using pulleys, e.g. wheels or cams, attached to each bow limb to create, along with the bowstring, a block and tackle effect that provides force multiplying characteristics and a reduced draw weight at full draw. The invention of the compound bow is attributed to Holless W. Allen and his invention is disclosed in U.S. Pat. No. 3,486,495. 
   However, typical compound bows create substantial vibration and noises when fired. For example, compound bows often have limbs attached to risers in limb pockets. Limbs will typically rattle and vibrate within the limb pockets when the bow is fired. Such noises can disturb game during bow hunting and cause misses or non-fatal hits. Furthermore, bow noise often represents vibration and lost energy that could otherwise be imparted to an arrow for increased velocity and accuracy. 
   Moreover, typical compound bows often require the use of a bow press for adjustment and/or assembly purposes as the limbs and bowstring of a typical compound bow are under significant tension. Thus, it is often difficult, if not impossible, to adjust a compound bow while hunting. Therefore, an adjustable compound bow with reduced bow noise is desired. 
   SUMMARY OF THE INVENTION 
   The present invention is an improved compound bow. In particular, the present invention is directed to an adjustable compound bow for hunting and archery with noise reduction features. The preferred embodiment of the bow comprises a riser having a main riser length with two ends, each end attached to an adjustable hub with a limb base. Each limb base preferably has a pocketless flat surface with vibration dampening material. Each hub is secured to the main riser length by an adjustment screw and a hub pivot. A limb is preferably secured to each limb base at two points on the pocketless flat surface. A bowstring is strung under tension between the limbs. The bowstring&#39;s tension can be adjusted by adjusting the adjustable hubs with the adjustment screws. The bow preferably has a storage position and an in-use position caused by rotating the limbs around the adjustable hubs. Adjustment of the bow can be accomplished without use of a bow press. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The objects and features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings. 
       FIG. 1  is a side view of a preferred embodiment of the invention in an in-use position; 
       FIG. 2  is a side view of a preferred embodiment of the invention in a storage position; 
       FIG. 3  is a side view of a preferred embodiment of a riser for the invention; 
       FIG. 4  is a front view of a preferred embodiment of a riser for the invention; 
       FIG. 5  is a side view of a preferred embodiment of an adjustable hub for the invention; 
       FIG. 6  is a side view of another preferred embodiment of the invention with a cable guide roller; 
       FIG. 7  is a side view of another preferred embodiment of the invention with a cable guide roller mounted to a removable bridge; 
       FIG. 8  is a side view of another preferred embodiment of the invention with a cable guide roller mounted in a bridge; and, 
       FIG. 9  is a front view of the preferred embodiment shown in  FIG. 8 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventor of carrying out his invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the general principles of the present invention have been defined herein specifically to provide an improved compound bow. 
   Referring now to  FIG. 1 , a preferred embodiment of the invention  10  is shown. The invention  10  is a compound bow comprising a riser  20  having main riser length  25 , a first end  22  and a second end  24 . Side and front views of the preferred embodiment of the riser  20  are shown in  FIGS. 3 and 4  respectively. The preferred embodiment of the riser has an arrow shelf  26  and a grip  28 . The riser  20  can be made of, inter alia, aluminum, aluminum-magnesium alloy, and/or aluminum-magnesium-carbon composite material. 
   Returning to  FIG. 1 , the first end  22  of the riser  20  is attached to a first adjustable hub  30  by a hub pivot  32  and a first adjustment means  33 . The second end  24  of the riser is attached to a second adjustable hub  35  by a hub pivot  32  and a second adjustment means  37 . The first end  22  and second end  24  are preferably forked to hold the respective hubs  30  and  35 . 
   The first adjustment means  33  and second adjustment means  37  are preferably screws. However, the adjustment means  33  and  37  can also be, e.g., a pin, cam or a latch. The adjustment means are preferably used to adjust the poundage of the bow. Tension pins  80  and  82  pass through the adjustment means  33  and  37  respectively. The tension pins roll to allow movement of adjustment means  33  and  37 . 
   The first adjustable hub  30  has a first limb base  31 . The second adjustable hub  35  has a second limb base  36 . A preferred embodiment of the first adjustable hub  30  with limb base  31  is shown in  FIG. 5 . Preferably, the limb bases  31  and  36  have a flat or convex surface where limbs can be attached. Additionally, the limb bases can have a vibration dampening material, e.g. elastomer, plastic, cloth, or a composite material on the flat or convex surface. The preferred embodiment of the first adjustable hub  30  (and the second adjustable hub  35  as well) also has an adjustment spur  39  to which the first adjustment means  33  attaches the hub  30  to the riser  20 . The preferred embodiments of the first and second adjustable hubs  30  and  35  do not have limb pockets into which limbs are inserted and attached to the hubs and/or riser. The hubs  30  and  35  can have available spaces and/or slots which can be filled with dampening material, e.g. urethane, silicone, rubber, etc., to reduce vibrations. 
   Returning to  FIG. 1 , a first limb  40  is attached to the first limb base  31  and a second limb  45  is attached to the second limb base  36 . Preferably, the first limb  40  is attached to the first limb base  40  at two points  41  and  42  and the second limb  45  is attached to the second limb base  36  at two points  46  and  47 . The limbs  40  and  45  are preferably secured to their respective limb bases  31  and  36  by flat head socket cap screws. Other securing means such as bolts, rivets and/or cam locks can be used. Alternatively, the limbs  40  and  45  can be attached to their respective limb bases  31  and  36  along a span of the limb contacting the limb base, or a portion thereof. Multiple or extended attachment points between the limbs and bases provide a more fixed base and reduce noise and vibration. The limbs  40  and  45  can have limb savers mounted on their surface to reduce vibrations. The limbs  40 ,  45  are preferably made of, inter alia, fiberglass or carbon composite material. 
   A first cam  50  is preferably attached to the first limb  40  and a second cam  55  is preferably attached to the second limb  45 . A bowstring  60  is strung around the cams  50  and  55  to create the “block and tackle effect” of the typical compound bow. Sound and vibration dampening items such as “cat whiskers,” “string leeches,” and “beaver balls,” can be applied to the bowstring  60  to further reduce sound and vibration during firing. 
   Referring now to  FIG. 2 , a preferred embodiment of the invention  10  is shown in a storage position. The preferred embodiment of the invention is shown in an in-use position in  FIG. 1 . As shown in  FIG. 2 , the bowstring  60  has been unstrung from the bow  10 . The first and second adjustment means  33  and  37  (not shown in  FIG. 2 ) have been released from the adjustment spurs  39 , thus releasing the spurs  39  from the main riser length  25 . This allows the hubs  30  and  35  to rotate around the hub pivots  32  and place the limbs  40  and  45  in the more compact storage position shown in  FIG. 2 . 
   Less drastic adjustment of the adjustment means  33  and  37  allows a user to adjust a bow&#39;s brace height. The brace height of a bow is the distance between the bowstring  60  and the grip  28 . An increased brace height generally means that the bow is more accurate but has less power. A decreased brace height generally means that the bow is less accurate but has more power. The general range of draw weight for the preferred embodiment of the invention is 15-100 pounds. 
   Without releasing the adjustment spurs  39  from the riser  20 , the adjustment means  33  and  37  can adjust the brace height of the bow  10 . The adjustment means  33  and  37  can be tightened or loosened to rotate the adjustable hubs  30  and  35  to move the limbs  40  and  45  and set the brace height of the bow  10 . Thus, the brace height of the bow  10  can be adjusted without the use of a bow press. Moreover, the adjustment means  33  and  37  and hubs  30  and  35  allow the bow to be changed from the storage position to the in-use position (and back) without the use of a bow press. 
   It should be noted that when longer limbs  40 ,  45 , e.g. 13-16 inches, are attached to the hubs  30 ,  35  (or a shorter riser is used), the tips of the limbs can touch each other when placed in the storage position and possibly prevent the bow from being placed in an optimum storage position. To avoid this, an alternative embodiment of the invention can comprise a riser  20  with a twist at its forked ends. The forked ends of the riser  20  are machined, cast or otherwise manufactured to cause the upper and lower forks to twist or be rotated in opposition to one another. Preferably, the upper fork is twisted 5-10 degrees clockwise and the lower forks twisted 5-10 counterclockwise. Accordingly, the hubs  30 ,  35  in this embodiment each preferably have an opposing twist such that when the bow is in an in-use position, the limbs  40 ,  45  are parallel and square to each other for accurate shooting. When the limbs  40 ,  45  are folded to the storage position, the twist in the riser  20  will cause the limbs  40 ,  45  to rotate away from each other to prevent the tips of the limbs from touching when in storage. In the storage position, the limbs  40 ,  45  preferably lay side by side. Another alternative would be to have a radius slot in one of the two mounting holes ( 41  or  42  and  46  or  47 ) on the limbs  40 ,  45 . The screws or other mounting means for limbs could then be loosened when relocation to the storage position is desired. The limbs  40 ,  45  then rotate on the hub  30 ,  35  allowing the limbs to lay side by side as mentioned above. 
   Referring now to  FIG. 6 , a side view of an alternate preferred embodiment is shown. Prior art compound bows can have a cable guide roller for the bowstring. This roller helps the bow draw more smoothly and moves the bowstring away from an arrow to be fired. However, the prior art cable guide roller is typically mounted to the riser with a cable guide roller arm or a cable guide bar with slider to distance the roller from the riser. However, when the preferred embodiments of the invention described above are placed in a storage position, a cable guide roller arm or cable guide bar with slider reduces their effectiveness for storage purposes. Thus, as shown in  FIG. 6 , a cable guide roller  100  mounted directly to the riser  20  is useful. By placing the cable guide roller  100  on the surface of the riser  20 , the bow can be placed in both storage and in-use positions with little or no impairment. 
   Referring now to  FIG. 7 , a side view of another alternative preferred embodiment is shown. In this embodiment, the cable guide roller  100  is mounted to a bridge  110  removably attached to the riser  20 . The bridge  110  and roller  100  can be removed from the riser  20  when the bow is placed in a storage position. This feature can simplify manufacture of the riser  20 . 
   Referring now to  FIGS. 8 and 9 , another alternative preferred embodiment is shown.  FIG. 8  is a side view of another alternative preferred embodiment with a cable guide roller  100 . However, the roller  100  is mounted within a cable guide roller compartment  120  (also visible in  FIG. 9 ) on the bridge  110 . This embodiment is advantageous because it has fewer parts and a better control cable angle between the tips of the limbs. This improved angle places the control cables deeper into the grooves of the cable guide rollers. The roller  100 , compartment  120 , and bridge  110  structure can also be referred to as a cable guide mount. The bridge  110  can be removably attached to the riser  20  or fixedly attached. 
   Thus, an improved compound bow is described above that is adjustable without a bow press and has reduced firing noise characteristics. In each of the above embodiments, the different positions and structures of the present invention are described separately in each of the embodiments. However, it is the full intention of the inventor of the present invention that the separate aspects of each embodiment described herein may be combined with the other embodiments described herein. Those skilled in the art will appreciate that adaptations and modifications of the just-described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.