Abstract:
An improved archery bow press used to relieve tension in the bow string of a compound archery bow so that maintenance and repair of the bow string and its components may be safely and easily accomplished. A threaded rod is mounted adjacent and parallel to an elongate beam allowing brackets slidable along the beam to be positioned at differing spacings therebetween. The threaded rod is turned by a crank perpendicularly extending from the threaded rod. Limb engaging arms are hinged to the slidable brackets. Link members are pivotably retained to the limb engaging arms and the link members are retainable to a telescoping part of a screw jack which is retained to the beam. At least one of the link members includes a pin support bracket along its length. The pin support bracket supports a tapered pin extending laterally from the pin support bracket over a bow placed in the bow press. While the bow is urging the limbs around their connections to the bow riser, the bow string may be passed over the pin after which the bow press may relax the limbs and provide tension on the bow string in a position deflected laterally from the plane of the bow riser.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 USC §119 to provisional application 61/142,426 filed Jan. 5, 2009, which is incorporated herein by reference. 
    
    
     BACKGROUND 
     A typical compound archery bow includes a pulley at one end and an eccentric cam at the appropriate end around which the cable of the bowstring is passed. The stringing or tuning of a twin cam bow, with its eccentrically mounted cam and its pulley, tension cable and bow string is critical to achieve a proper balance of the eccentrically mounted pulleys or cams. The complexity of the stringing and the sensitivity to proper tuning of the bow, makes it very difficult to string and tune a compound bow without the aid of a bow press. 
     Periodic retuning of compound bows is often required to maintain desired performance levels. For this and to change, replace or repair components of the compound bow, such as the bowstring, string sights, dampers, the tension cable, the cams and other components, a bow press is essentially required. 
     Through the years a number of bow presses have been developed for facilitating stringing and maintenance of compound bows. In general, these presses have included a stationary base having a pair of spaced apart inside surface supports, in the form of pegs or rollers, for contacting the inside of the bow, and a pair of limb supports, in the form of pegs or rollers, attached to a movable mechanism for applying a bending force to the limbs of the bow. Such a bow press is described in Gibbs, U.S. Pat. No. 6,968,824. 
     It is very important that the inside surface support and the limb supports of the bow press be precisely positioned in such a manner that the bow is properly loaded into the press in a manner that when the limbs are bent, the forces will not overstress or otherwise damage the bow. Because compound bows vary dimensionally, particularly in riser length, it is necessary that the inside surface support and the limb supports on the bow press be adjustable. In the past, it has been customary to provide incremental holes in the bow press so that the position of the inside surface support and the limb supports could be moved to achieve a satisfactory fit with regard to a given bow. The incremental nature of this adjustment approach often results in a fit of the bow press to the bow which is not quite ideal, and can result in damage to the bow. In the patent to Gibbs, U.S. Pat. No. 6,968,834, an improvement is made to allow manually adjustable sliding clamps which are selectively moveable along a beam and where located properly, may be clamped to the beam by tightening bolts or set screws. 
     Prior bow presses are not easy to adjust, in that the movable components are typically bolted to the bow press or clamped along a beam, thereby requiring the use of wrenches or special care for making necessary adjustments. A more expeditious and convenient adjustment apparatus is needed. 
     It is desirable, therefore, to provide an improved bow press apparatus and method which overcomes one or more of the problems described above, or other problems and shortcomings of prior bow presses. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improved archery bow press used to relieve tension in the bow string of a compound archery bow so that maintenance and repair of the bow string and its components may be safely and easily accomplished. 
     The archery bow press provides a support base supporting an elongate beam oriented horizontally. An upright screw jack is located midway along the beam and is retained to the beam. An elongate threaded rod is mounted to the base adjacent and parallel to the elongate beam. The threaded rod is supported at each opposing end and the rod is also supported in a central bearing where the rod contains no threads. The first half of the rod is threaded with right hand threads and the second half of the rod is threaded with left hand threads. A pair of pivot arm bracket members is slidable along the beam with one bracket member on each opposing side of the midpoint of the beam. The pivot arm bracket members are coupled to the threads of the threaded rod such the rotation of the rod will cause the pivot arm bracket members to be drawn together or moved apart depending on the direction of rotation of the threaded rod. A gear box is mounted at one end of the threaded rod which provides a coupling for a crank handle such that the crank handle may have an axis perpendicular to the axis of the threaded rod. Limb supporting arms are hinged to each of the pivot arm bracket members and each limb support arm has a limb support bracket member slidable along its length. Each of the limb support bracket members is hinged to an elongate link member with each of the link members selectively and adjustably mounted to the screw jack which is retained to the midpoint of the beam. A laterally extending rod which is physically cushioned is retained to each pivot arm bracket such that a bow can be removably retained to each laterally extending rod by elastomeric bands with the bow suspended under the laterally extending rods. The pivot arm brackets are caused to move along the beam by use of the crank handle which rotates the elongate threaded rod, so that the pivot arm brackets can be placed below the connections of each of the bow limbs to the bow riser. Another set of cushioned retaining rods is mounted to each limb support bracket member such that each cushioned retaining rod may support the underside of a limb near its distal end. A pin support bracket is adjustably retained to each of the elongate link members by a clamping device. Each pin support bracket supports a horizontally projecting tapered pin having a generally conical shape and having an annular groove near the tip of the pin into which the bow string of the compound bow may be temporarily placed during repair and maintenance of the bow string. 
     In another use of the archery bow press, with the limbs of the bow urged toward each other to reduce tension on the bow string, a cable section of the bow string may be detached from the bow and attached to one of the tapered pins, whereupon the screw jack may be lowered to relieve deflection of the limbs relative to the riser. A flexible strap may be employed to temporarily connect a segment of the bow string to the bow riser in order to place tension on the bow string. With this application, the cable section attached to a pin may then be refurbished. 
     Because of the gear box permitting a crank to be used which extends perpendicularly from the axis of the threaded rod, a user need not move from a position near the riser of a bow in the bow press while adjusting the spacing of the pivot arm bracket members away from the opposing ends of the beam because when the spacing between the pivot arm brackets is being selected, it is to conform the distance between the retaining rods which are to engage the inner face of the bow riser so that the those retaining rods are spaced just inboard of the connection of the bow limbs to the bow riser. 
     It is accordingly an object of the invention to provide an improved bow press which allows easy adjustment of the bow press to accommodate the length of bow riser of a bow to be pressed while the user suspends the bow below the lateral rids extending from the pivot arm brackets of the bow press. 
     Further objects of the invention are: to provide a bow press which allows a continuous variety of spacings between the pivot arm brackets, to provide an improved bow press which allows the bow string to be deflected and retained forward of the plane of the bow riser and limbs, to provide an improved bow press which provides a terminal to which to attach a cable end detached from the cam or pulley of the bow, to provide an easy to use bow press which allows operation of the bow press by a lone user without assistance from a helper. 
     These and other objects of the invention will be understood from the detailed description of the invention which follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS ACCORDING TO THE PRESENT INVENTION 
         FIG. 1  is a front elevation of the archery bow press with a compound bow installed on the bow press. 
         FIG. 2  is a side plan view of the archery bow press of  FIG. 1 . 
         FIG. 3  is a front elevation of the archery bow press of  FIG. 1  with a compound bow installed thereon and with one end of the bow string cable disconnected from one limb of the bow and secured to an element of the bow press 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-3  illustrate an exemplary embodiment of an archery bow press  10  according to the invention for deflecting the limbs  12 ,  14  of an archery bow  16  relative to the riser  20  thereof, to allow installation, replacement, repair or adjustment of a bow string  18  of the bow  16 . The bow  16  includes a riser  20  from which limbs  12 ,  14  extend from opposing ends thereof. The bow  16  includes a pulley  25  at the distal end of limb  12  and a cam  22  at the distal end  15  of the limb  14 . 
     Bow press  10  includes an elongate main beam  26 , first and second pivot arms  28 ,  30 , and pivot arm brackets  56 ,  58  which retain the first and second pivot arms  28 ,  30  to the main beam  26 . First and second pivot arms  28 ,  30  are adapted for urging the limbs  12 ,  14  toward each other to relieve tension on the bow string  18 . 
     The first and second pivot arms  28 ,  30  are spaced from one another along the main beam  26 , with each of the first and second pivot arms  28 ,  30  having a hinged end  38  and a distal end  40 . The pivot arm brackets  56 ,  58  are slidingly retained to the main beam  26 . 
     The hinged end  38  of each pivot arm  28 ,  30  is attached by pivot arm bracket  56 ,  58  to the main beam  26 , for pivoting motion about pivot axles  42 ,  44  which retain pivot arms  28 ,  30  to pivot arm bracket  56 ,  58 , such that pivot arms  28 ,  30  move in a common plane with main beam  26 . 
     An upstanding screw jack  50  is mounted to main beam  26  by mounting assembly  52  and extends upward perpendicularly from the main beam  26  at its midpoint  27 . 
     An adjustment rod  64  is interconnected with each pivot arm bracket  56 ,  58  by screw followers  57 ,  59  such that simultaneous selective sliding movement of the first and second pivot arm brackets  28 ,  30  may be effected along the main beam  26 , toward or away from the midpoint  27  of beam  26 . 
     The adjustment rod  64  is retained to the main beam  26  by central bracket  29  which allows adjustment rod  64  to turn freely. Adjustment rod  64  is provided with screw threads therealong with the pitch of the threads  61  of the left end  63  reversed to the pitch of the threads of the right end  65 , that is threads  61  may be right hand threads and threads  67  may be left hand threads, or vice versa. Adjustment rod  64  is operatively connected to the first and second pivot arm brackets  56 ,  58  such that both pivot arm brackets  56 ,  58  move at the same rates of travel along the main beam  26  though in opposing directions. 
     The exemplary embodiment of the bow press  10  includes a first inside surface support  78 , adapted for contacting an inside surface  80  the first limb  12  near its connection to the riser  20 . The invention allows the first inside surface support  78  to be placed as close as possible to the connection of the first limb  12  to the riser  20 , so that the bow  16  can bend in the bow press  10  about the interconnection of the first limb  12  and the riser  20 . Similarly second inside surface support  84  contacts inside surface  86  of limb  14  near its connection to riser  20 . Preferably inside surface supports  78 ,  84  are cushioned cylindrical rods. Elastic bands  87  selectively are applied to bow  16  to retain bow  16  to inside surface supports  78 ,  84 . 
     The first inside surface support  78  is attached to the first pivot arm bracket  56  so that its axis is at a short fixed distance inboard of the first pivot axle  42 , with respect to the midpoint  27  of beam  26 . This closely adjacent but slightly inboard positioning of the first inside surface support  78  with respect to the pivot axle  42  of the first pivot arm  28 , together with having both the first inside surface support  78  and first pivot axle  42  located at a fixed distance from one another on the first pivot arm support bracket  56 , provides an advantageous arrangement for properly supporting the inside surface  80  of the bow  16  in a manner that allows the first limb  12  to flex during use of the bow press  10  in a manner that is very similar to the way the first limb  12  flexes when the bow  16  is in normal use. 
     The second inside surface support  84  is attached to the second pivot arm bracket  58  so that the axis of second inside surface support  84  is a short fixed distance inboard of the second pivot axle  44 , with respect to the midpoint  27  of beam  26 . This closely adjacent but slightly inboard positioning of the second inside surface support  84 , with respect to the pivot axle  44  of the second pivot arm  30 , together with having both the second inside surface support  84  and second pivot axle  44  located at a fixed distance from one another on the second pivot arm bracket  58 , provides an advantageous arrangement for properly supporting the inside surface  86  of the limb  14  in a manner that allows the second limb  14  to flex during use of the bow press  10 . 
     The bow press  10  further includes a first limb deflector bracket  88  slidingly attached to the first pivot arm  28 , with a first limb engaging arm  90  extending laterally from the first limb deflector bracket  88 . The first limb engaging arm  90  is adapted for contacting an outside surface  97  of the first limb  12  at a point along the first limb  12  displaced from its connection to riser  20 . The first limb deflector bracket  88  includes a locking mechanism  94  for locking the first limb deflector bracket  88  to the first pivot arm  28  at a selected location with respect to the first pivot axle  42 . Limb engaging arms  90 ,  92  are relatively short but preferably extend perpendicularly from each of pivot arms  28 ,  30 . 
     In similar fashion, a second limb deflector bracket  96  is slidingly attached to the second pivot arm  30  and includes a second limb engaging arm  92  extending laterally and perpendicularly from the second limb support bracket  96 , with the second limb engaging arm  92  contacting an outside surface  99  of the second limb  14  at a point along the second limb  14  spaced away from riser  20 . The second limb deflector bracket  96  includes a locking device  102  such as a locking screw which selectively locks the second limb deflector bracket  96  against movement along the second pivot arm  30  at a selected location with respect to the second pivot axle  44 . 
     The bow press  10  further includes a screw jack  50  substantially centered On beam  26 , as well as a first link  108  and a second link  110 . The screw jack  50  has a stationary base section  112  attached to the main beam  26  of the bow press  10  by jack mounting brackets  52 . The screw jack  50  further includes an extensible section  113  telescoping from base section  112  of the screw jack  50 . The screw jack  50  is attached to the main beam  26  at its midpoint  27  in such a manner that when first screw crank  115  is turned, the extensible section  113  of the screw jack  50  extends or retracts from base section  112 . 
     The first and second links  108 ,  110  each have a first end  109 ,  111  pivotably attached respectively to the first and second limb engaging arms  90 ,  92 , so that each pivots freely with respect to pivot arms  28 ,  30 . The first and second links  108 ,  110  cross and are each removably joined to the other by a pin  116  mounted to and extending perpendicularly from the extensible section  113  of the screw jack  50 . 
     The first and second links  108 ,  110  have equal lengths between their respective first ends  109 ,  111 , and the common connection provided by the pin  116 . The screw jack  50  functions to raise and lower both pivot arms  28 ,  30  together thereby exerting lifting force to limb engaging arms  90 ,  92  and hence applying bending force to the limbs  12 ,  14  of bow  16  mounted in the bow press  10 . 
     Each of first and second links  108 ,  110  includes a pin support bracket  120 ,  121  which may be selectively slideable along the respective link  108 ,  110 . Adjustment of pin support brackets  120  along links  108 ,  110  is accomplished by loosening lock screws  128  of each pin support bracket  120 ,  121 . Each pin support bracket  120 ,  121  includes a protrusion, preferably a cylindrical pin  122 , extending horizontally therefrom generally perpendicular to links  108 ,  110  and extending over bow  16 . From  FIG. 2  it can be seen that cylindrical pins  122  are preferably tapered and each includes a groove  124  near its free end  126 . The grooves  124  are selected to receive the bow string  18  when deflected from its ordinary use position. The length of pins  122  and placement of grooves  124  on each pin  122  are selected such that they preferably lie outside the plane defined by the centerline of the bow riser  20  and the beam  26 . Therefore, with the tension on bow string  18  relaxed by flexing of limbs  12 ,  14 , the nock portion  17  of the bow string  18  may be displaced from the cable sections  19 ,  21  of the bow string  18 . Then the extensible section  113  of screw jack  50  may be lowered, returning tension to bow string  18 . Replacement of worn or broken serving wrapped around nock portion  17  may be easily accomplished when the nock portion  17  is pulled upward and placed on grooves  124  of pins  122 . Pins  122  serve to laterally and vertically separate nock portion  17  from the remainder of bow string  18 . 
     First end  140  of adjustment rod  64  is coupled to a gear box  142  adapted to allow adjustment rod  64  to be rotated from a perpendicular direction. Specifically gear box  142  houses a spider gear which allows a second crank  118  to apply rotational force to crank coupling  144  of gear box  142  with the result that adjustment rod  64  rotates. As adjustment rod  64  rotates, threaded couplers within each of screw followers  57 ,  59  are driven by opposing threads  61 ,  67  causing pivot arm brackets  56 ,  58  to converge or diverge at equal rates. Thus pivot arms  28 ,  30  are symmetrically adjusted to accommodate the length of a bow  16  to be pressed. Because the bow  16  to be pressed in bow press  10  must be supported by the user as the pivot arms  28 ,  30  are moved, having a crank coupling  144  facing the holder of the bow  16  eases the chore of adjusting the bow press  10  to fit the bow  16  such that inside surface supports  78 ,  84  are positioned just outboard of the limb connections of limbs  12 ,  14  to riser  20 . Then elastic straps  87  can be applied to suspend bow  16  from inside surface supports  78 ,  84 . 
     Importantly, gear box  142  at first end  140  of adjustment rod  64  permits rotation of adjustment rod  64  by a user using second crank  118  to rotate the crank coupler  144  while standing in front of bow press  10  and holding bow  16 . This allows the user to easily reposition the pivot arm brackets  56 ,  58  while suspending the bow  16  with one hand until the separation of pivot arm brackets  56 ,  58  is appropriate so the bow limbs  12  and  14  are supported properly. 
       FIG. 3  illustrates the bow press  10  in use to support bow  16  while cam end  131  of cable portion  21  of bow string  18  is repaired. With bow  16  placed onto bow press  10  with extensible section  113  retracted into stationary section  112  of screw jack  50  such that limb engaging arms  90 ,  92  do not touch limbs  12 ,  14 , and with bow string  18  attached to bow  16  in condition for use, extensible section  113  may be raised thereby flexing limbs  12 ,  14  toward screw jack  50 . Deflection of limbs  12 ,  14  toward each other relaxes tension on bow string  18  and permits detachment of first cam end  131  of cable portion  21  of bow string  18  from cam  22 . Cable portion  21  can then be passed around tapered pin  122  of second pin support bracket  121  and attached to pin  122  of first pin support bracket  120  which is attached to first link  108 . A variable length strap  160  may be placed around both cable portion  21  and riser  20  to retain cable portion  21  to riser  20 . Thereafter, extensible section  113  of screw jack  50  is lowered, returning tension to bow string  18 . By careful attention to the preservation of twist in bow string  18  when it is detached from cam  22  and hooked to pin  122  of first pin support bracket  120 , the tuning of bow string  18  can be preserved while repair to serving wound around cable portion  21  is accomplished. Once repair has been completed, such as by replacement of serving around the end section  23  of cable portion  21 , extensible section  113  can again be extended thereby pressing limbs  12 ,  14  toward each other and detensioning bow string  18 . This permits easy and safe removal of strap  160  and reattachment of cam end  131  to cam  22  while tuning of bow string  18  is maintained as previously set. 
     When the bow press  10  is to be used, the position of the inside surface supports  78 ,  84  and limb engaging arms  90 ,  92  are adjusted to fit the bow  16 . First crank  115  is applied to screw jack  50  to retract the extensible section  113  of the screw jack  50  to an initial position where the bow  16  can be inserted without resistance into the press  10  with the inside surface supports  78 ,  84  generally on the inside of the bow  16  and closely adjacent the attachments of the first and second limbs  12 ,  14  to the riser  20 . Adjustment of the spacing of pivot arm brackets  56 ,  58  is accomplished by turning adjustment rod  64  with second crank  118 . The limbs  12 ,  14  will be inboard of the first and second limb engaging arms  90 ,  92 . 
     The connection point between the first and second links  108 ,  110  may also be adjusted if necessary by repositioning pin  116  in different holes in links  108 ,  110  to allow placement of the bow  16  into the bow press  10 . Adjacent holes in the links  108 ,  110  are laterally offset from one another to aid in visually connecting the links  108 ,  110  to the pin  116  in such a manner that the links  108 ,  110  have equal lengths between their respective first ends at the first and second limb engaging arms  90 ,  92 , and the common connection provided by the pin  116 . 
     By virtue of the construction of the bow press  10  as described above, the position of the first and second pivot arm brackets  56 ,  58  along the beam  26  is easily adjustable to thereby allow for very precise and proper positioning of the location of the inside surface supports  78 ,  84  to match the bow  16 . Also, by virtue of the coupling of adjustment rod  64  to pivot arm brackets  56 ,  58 , as either of the first or second pivot arm brackets  56 ,  58  is moved along the beam  26 , the other pivot arm bracket moves an equal distance in the opposite direction along the beam  26 , so that the first and second bow supports  78 ,  84 , and the pivot pins  42 ,  44  are always maintained at symmetrical locations with respect to the upstanding screw jack  50 , regardless of where either of the pivot arm brackets  56 ,  58  is positioned along the beam  26 . 
     The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations of the embodiments are possible in light of the above disclosure or such may be acquired through practice of the invention. The embodiments illustrated were chosen in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto, and by their equivalents.