Abstract:
An archery bowstring release includes a hand grip having a forwardly extending post pivotally mounting a bowstring hook member releasably engaged by a locking mechanism that serves to adjust the position of the hook on the hook member for releasing a bowstring and projecting an arrow to a target. In one embodiment, the hook member is secured adjustably to the post. In another embodiment, the hook member is mounted pivotally on a support frame carried pivotally on a cam member pivoted to the post and arranged to engage the hook member for release by pivotal movement of the support frame through a small angle by adjustment of the cam member rotationally relative to the post. The hook member may be secured adjustably to the post or cam member either by a pin and groove assembly or by a worm gear engaging a gear on the hook or cam member.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to archery bows, and more particularly to a novel bowstring release. 
     Release devices are employed by archers to protect the fingers from injury and to enable release of a bowstring with minimum adverse influence of an archer&#39;s involuntary movements during the aiming and bowstring release actions. 
     In manner analogous to the aiming and firing of a rifle or handgun, in which involuntary movements of the hand, finger or other component of the body results in inaccurate striking of a target, so also do such involuntary movements result in inaccurate hitting of an archery target with an arrow. A major source of such errors stems from the mental anticipation of moving the fingers of a hand to pull the trigger of a gun or to release an archery bowstring. In both activities the mental instructions to the fingers induce anxiety and tension in those and other components of the body, causing involuntary movements which adversely affect the accuracy of aiming at and striking the target. 
     U.S. Pat. Nos. 5,694,915; 3,965,884; and 3,853,111 disclose triggerless bowstring release devices in which a bowstring hook is arranged to release a bowstring by pivoting the device laterally, by movement of the archer&#39;s hand or fingers. However, none of these devices provides faithfully reproducible, substantially infinite degrees of sensitivity adjustments for insuring consistent shooting accuracy. 
     SUMMARY OF THE INVENTION 
     This invention provides a bowstring release in which a bowstring hook member is held releasably in a reproducibly repeatable locked position against a locking member until the hook member is moved a distance sufficient to disengage from the locking member, the distance to be moved being adjustable for variable sensitivity and the disengagement being unpredictable, whereby to avoid involuntary hand and body movements. 
     It is the principal objective of this invention to provide a bowstring release that overcomes the aforementioned limitations and disadvantages of prior bowstring releases. 
     Another objective of this invention is the provision of a bowstring release of the class described that allows aiming and release of an arrow from an archery bow without adverse influence from involuntary movements of the archer. 
     Still another objective of this invention is to provide a bowstring release of the class described in which release from a bowstring is achieved by movement of a bowstring hook member from a locked position holding a bowstring in drawn condition to a bowstring release position, without the archer knowing in advance at what position or condition the bowstring is released. 
     A further objective of this invention is the provision of a bowstring release of the class described in which movement of a bowstring hook member from locked to release position is adjustable, whereby to vary the position of draw and sensitivity of bowstring release, and thereby further remove from the archer the knowledge of the position of bowstring release. 
     A still further objective of this invention is the provision of a bowstring release of the class described which is of simplified construction for economical manufacture, which is precise in its operation and provides faithfully reproducible, substantially infinite degrees of sensitivity of release throughout a predetermined range. 
     The foregoing and other objects and advantages of this invention will appear from the following detailed description, taken in connection with the accompanying drawings of preferred embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a longitudinal sectional view of a first embodiment of bowstring back tension release embodying the features of this invention, showing details of internal construction of a first form of adjustment mechanism for varying the distance of movement of the hook member of the release. 
     FIG. 2 is a longitudinal cross section, similar to FIG. 1, showing details of internal construction of a second form of adjustment mechanism for varying the distance of movement of the hook member of the release. 
     FIG. 3 is a longitudinal cross section of a second embodiment of bowstring back tension release embodying features of this invention, the adjustment mechanism being the same as in FIG.  1 . 
     FIG. 4 is a longitudinal cross section of the hook release mechanism of FIG. 3 but with the adjustment mechanism of FIG.  2 . 
     FIG. 5 is a longitudinal cross section similar to FIG. 4 showing in full lines the positions of the components securing an archery bowstring to the hook component in the latched position for drawing a bowstring, and showing the hook release position in broken lines. 
     FIG. 6 is a longitudinal cross section of a third embodiment of bowstring back tension release embodying features of this invention, the adjustment mechanism being the same as in FIG.  1 . 
     FIG. 7 is a longitudinal cross section similar to FIG. 6 showing in broken lines adjustment of the hook member and associated components to a more sensitive release position of the bowstring. 
     FIG. 8 is a longitudinal cross section of a fourth embodiment of bowstring back tension release embodying features of this invention, the structure being similar to FIG. 4 but including a positive safety mechanism for the hook. The components are shown in the bowstring retaining position. 
     FIG. 9 is a longitudinal cross section of the fourth embodiment shown in FIG. 8, but with the components in the bowstring released condition. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The drawings illustrate the common structural features of all embodiments to include a hand grip member  10  from which a center post  12  extends forwardly, intermediate the ends of the hand grip member. An end post  14  is provided with a thumb surface  16  by which to support a thumb of the archer&#39;s hand. An index finger pocket  18  is formed between the center post and end post. 
     Referring now primarily to FIGS. 1 and 2 of the drawings, a bowstring hook member  20  is disposed between the bifurcated end tabs  12 ′ of the center post and is secured to the post by pivot pin  22  which extends through the end tabs and an intermediate portion of the hook member. The outer end of the hook member is provided with a bowstring retaining hook  24  for capturing a bowstring S. 
     FIG. 1 shows the hook member  20  to have an arcuate inner portion provided with a gear thread  26  throughout a predetermined arc of pivotal movement of the hook member. A worm screw  28  is mounted in a transverse retainer bore  30  which is open at one end and closed at the opposite end  32 . The worm screw is provided with a screwdriver slot  34  which is exposed through the open end of the bore and serves to receive a screwdriver tool for rotating the worm screw and correspondingly rotating the hook member  20  about the axis of the pivot pin  22 . 
     The worm screw is retained in desired position of rotational adjustment by means of a clamp screw  36  received in a threaded portion of the bore  38  which extends forwardly from the rear side of the hand grip  10 . A soft plug  40  of plastic or other suitable material on the forward end of the clamp screw serves to bear against the worm screw to secure it frictionally against rotation from its desired setting. 
     In FIG. 2 the end of the bowstring hook member  20  opposite the hook  24  is configured arcuately and provided with a plurality of closely spaced sensitivity grooves  42  extending throughout a predetermined arc of adjustment. An elongated sensitivity pin  44  is mounted slidably in a bore  46  which extends from the rearward side of the hand grip member  10  forwardly through the center post  12  to the bifurcated tabs  12 ′. The pin is provided with a pointed forward edge  48 . The pin is round in cross section and provided with an elongated flat  50  which is engageable releasably by a stabilizer and lock screw  52 . The screw bears against the flat  50  to prevent rotation of the pin, and may be turned down to bear firmly against the flat to lock the pin against longitudinal movement when the pin edge  48  is secured in the desired one of the sensitivity grooves  42 . 
     The rearward end of the pin  44  is provided with a reduced diameter portion  54  which serves to center a coil spring  56  at its forward end. The rearward end of the coil spring engages an abutment screw  58  received in a threaded section of the bore  46 . The coil spring thus serves to retain the pointed edge  48  of the pin against the grooves  42  retractably to allow pivotal adjustment of the hook member  20 , for sensitivity adjustment, as explained more fully hereinafter. 
     The hook member  20  may be provided with holes  60  for the mounting of a conventional rope release, as will be understood. 
     Referring now to the embodiment illustrated in FIGS. 3-5, a cam member  62  is positioned between the bifurcated end tabs  12 ′ of the center post  12  and is secured therein by pivot pin  64 . In the embodiment illustrated in FIG. 3, the rearward portion of the cam member is arcuate in configuration and provided with a gear thread  66  for cooperative engagement with a worm screw  28 , as described hereinbefore. The forwardly facing side  68  of the cam member  62  is flat, and serves to engage a hook member described hereinafter. 
     A hook member support frame  70  is provided with spaced side walls  72  and back wall  74 . The side walls are provided with registering openings for reception of the pivot pin  64 . The hook support frame thus is pivotable about the axis of pivot pin  64 , independently of the cam member  62 . 
     A hook member  76  is positioned between the support frame side walls  72  on pivot pin  78 . The forward end of the hook member is provided with a hook  80  configured to retain an archery bowstrings. The rearward end of the hook member forms a finger  82  which releasably engages the cam member  62  adjacent the back wall  74  of the hook support frame  70 . The degree of interengagement between the finger and forward side  68  of the cam member is adjustable by rotation of the cam member by the worm screw  28 , in the manner previously described. The cam member preferably is provided with a notch  84  adjacent the flat side  68  of the cam member confronting the hook member finger  82 , to provide the archer with a “click” sound alert that the position of hook release is pending. 
     In FIG. 4 the assembly of cam member  62 , hook support frame  70  and hook member  76  are the same as in FIG. 3, with the exception that the arcuate rearward end of cam member  62  is provided with sensitivity grooves  86  for association with sensitivity pin  44  and related components shown in FIG.  2 . 
     FIG. 5 illustrates the operation of the release embodiment of FIGS. 3 and 4. With the cam member  62  rotated and secured in a desired position of sensitivity of hook release, the hook support frame  70  is rotated counterclockwise about the axis of pivot pin  64  until the finger  82  of the hook member  76  can be brought into abutment with the adjacent end of the flat forward end  68  of the cam member. The hook support frame  70  then is rotated clockwise to draw the finger  82  of the hook member  70  into engagement with the cam member, whereby to lock the hook member against release. The forward hook  80  then may be brought into retaining engagement with a bowstring and the release assembly pulled rearward to a position approaching full draw of the bowstring. As the full draw position is approached, the rotation of the arm and hand of the archer rotates naturally to a position at which the tension in the back of the archer causes a further slight rotation of the hand and consequent lateral tilting of the hand grip member  10 . This movement is accompanied by a slight counterclockwise rotation of the hook support frame  70  and corresponding retracting movement of the finger  82  of the hook member  76  from the cam  62 . 
     If the alert notch  84  is provided, the finger  82  of the hook member first snaps into the notch, giving the archer an audible indication of the pending point of release of the hook member. A further slight, but imperceptible movement of the archer&#39;s arm and hand to complete the full draw position, results in the finger being disengaged from the can member, whereupon the hook member is instantly released and rotated to the broken line position of FIG.  5 . 
     The structural arrangement illustrated in FIGS. 3-5 is uniquely effective in allowing an archer to bring an archery bow to full draw and subsequent release of the bowstring at an unpredictable position, thereby avoiding all involuntary movements which mental anticipation would otherwise induce anxiety and tension, resulting in adversely effecting the accuracy of aiming at and striking a target. 
     In the embodiment of FIGS. 1 and 2, the hook member  20  is adjustable to a position of angular rotation about the axis of pivot pin  22 , either by the worm screw  28  or the sensitivity pin  44 . It is the movement of the archer&#39;s arm and hand at the position approaching full draw that the final condition of back tension in the archer causes a slight rotation of the archer&#39;s arm and hand to tilt the hand grip member  10  laterally to an extent allowing the bowstrings to slide off the hook  24 . The degree of sensitivity at which this disengagement occurs is adjustable throughout the substantially infinite number of increments of rotation of the hook member  20  through the predetermined arc afforded by the sensitivity gear  26  or sensitivity grooves  42 . 
     The embodiment of FIGS. 6 and 7 is similar to the embodiment of FIG. 3 but with a hand grip member  10 ′ shaped to fit the contour of the fingers of an archer&#39;s hand and to facilitate the lateral rolling of the hand grip member. The hook member  88  also is provided with a stop  90  spaced from the finger  92  by an intermediate cavity  94 . The stop  90  bears against the forward flat cam side  68  and cam  62  is rotated by the worm gear  28  to adjust desired overlapping engagement with the edge of cam  62 , to provide the corresponding degree of sensitivity of bowstring release from the hook  96 . In FIG. 7 the broken lines show rotation of the cam  62 , frame  70  and hook member  76  clockwise to positions affording a more sensitive release of bowstring S from hook  96 . 
     The embodiment of FIGS. 8 and 9 is similar in structural configuration to that of FIG. 4, but with the addition of a positive safety mechanism for preventing premature release of the hook  76 . The safety mechanism includes a safety lever  100  contained freely in a slot  102  in the hand grip member  10  and secured intermediate its ends on pivot pin  104 . One end of the safety lever is configured with a thumb piece  106  by which the thumb of an archer may be used to pivot the lever. A cavity  108  adjacent the end of the lever opposite the thumb piece  106  contains and seats one end of a coil spring  110  the opposite end of which abuts the bottom side of the slot  102 . Intermediate the pivot pin  104  and thumb piece  106  the lever  100  has a forwardly projecting node  112  arranged to engage the rearward end of pin  44 . Pivotal movement of the lever thus serves to extend or retract the pin relative to the cam member  62 . 
     When the thumb piece  106  is drawn rearward, against the resilient resistance of coil spring  110 , safety lever  100  is rotated counterclockwise and the pointed end  48  of pin  44  is retracted from the groove  86  in cam member  62 . The cam member thereupon is free to rotate to the position predetermined by the adjustment of the hook screw  114  which has a threaded shank received in a threaded bore in the hook member  76 . The hook screw establishes the amount of sear engagement between the cam member  62  and hook member  76 . 
     The spring  110  urges the safety lever  100  resiliently clockwise to its operative position in which the raised node  112  engages pin  44  and moves its pointed end  48  into engagement with one of the sensitivity grooves  86  in the arcuate rearward end of cam member  62 . The release then may be rotated by motion of the archer&#39;s hand until the cam member  62  is moved out from under the hook member  76 , thereby releasing the bowstring and projecting the arrow to its target. 
     It will be apparent to those skilled in the art that various changes may be made in the size, shape, type, number and arrangement of parts described hereinbefore. For example, the safety lever mechanism may be incorporated in the previously described embodiments by modification of the configurations of the pins  44  to enable their operative association with the node  112  on the lever  100 . This and other modifications may be made without departing from the spirit of this invention and the scope of the appended claims.