Abstract:
A bowstring archery bow breech structure having a trigger for releasing the drawn bowstring solely by the physical action of the shooter, wherein a spring mechanism is provided which functions to impart a lost motion action to the pull at a preselected drawstring pull force, wherein the trigger is designed to be pulled by the shooter in an axial direction during the lost motion action and as the result of the lost motion movement of the shooters hand rather than by any independent manipulation of the trigger by the shooter fingers, and wherein the keeper structure is formed with a unique configuration of a shoulder and peg for holding a keeper loop and the bowstring in a more axial position with respect to the arrow axis during the non-firing and the bowstring release stages, and wherein shoulder means is provided for holding the pulled bowstring without the use of a keeper loop.

Description:
This application is a divisional of applicants pending (allowed) Ser. No. 10/824,558 filed Apr. 14, 2004 which is a continuation-in-part of applications Ser. No. 10/616,792, filed Jul. 10, 2003, now abandoned, of same title. 

   BACKGROUND OF THE INVENTION 
   1. Field 
   This invention concerns a unique breech device for archery bows, i.e., for target or hunting bows, especially for compound bows, and particularly concerns a firing mechanism therefore, wherein the bow string is retained by a releasable latch mechanism such as a conventional keeper, which breech device can be quickly removably mounted on the archer&#39;s hand (fingers) by a sling device. 
   2. Prior Art 
   Heretofore, many bowstring release or firing mechanisms have been proposed, a few of which are shown, for example, in U.S. Pat. Nos.: 4,041,926; 5,448,983; 4,567,875; 4,309,975; 4,458,659; and 4,022,181, the disclosures of which are hereby incorporated herein in their entireties. Such mechanisms typically are encumbered in one or more of the aspects of structural complexity, cost of manufacture, dimensionally too large for rapid deployment in the field, difficult to use rapidly and to recock, bulkiness when stored in pockets or the like or when simply being held in the archers hand, lack of smoothness and accuracy in use, excessive physical abuse of the bowstring upon repeated firings, cocking of the mechanism requiring excessive motion by the archer which is visible to game, a partial pull of the trigger cannot easily be retracted where the archer changes his mind not to shoot at that particular instant, or requires too much time to retrieve from a pocket or the like and properly affix to a bowstring. 
   A more sophisticated firing mechanism is shown in U.S. Pat. No. 6,173,706B1, the disclosure of which is hereby incorporated herein in its entirety. As shown in  FIG. 1  of this patent the type of bowstring keeper which is preferred for the present invention is shown as item  54  and the preferred latch arrest shoulder means is shown as roller  29 . Also useful with the present invention is the finger sling  80  of this parent and its operation. As will hereinafter become apparent, difficulties in the use of the trigger member  32  in this patent arises from the fact that the trigger is in a form which requires a conscious finger action of squeeze or pull for firing, wherein the finger action is essentially disassociated from the pulling action of the archer which emanates mainly from the archers shoulder and back muscles. This independent finger action generates its own force vectors which typically are not aligned with the archers pull axis and results, for example, in a sideways jerking of the bowstring, albeit of small degree but quite significant to shooting accuracy. 
   In U.S. Pat. No. 6,481,430B1, a firing mechanism is disclosed which automatically releases the bowstring when a threshold pull force is applied. However, a safety device is required to prevent premature release of the bowstring, which device is particularly necessary in the use of compound bows as will hereinafter be more fully explained, and the archer must manually unlatch the safety device by finger manipulation in order to fire. 
   OBJECTS OF THE INVENTION 
   A principal object therefore, of the present invention is to provide a unique trigger mechanism which uses, to a substantial degree, the bowstring pull action of one lateral set of the archers shoulder and back muscles and the bow push action of the other lateral set of the archers shoulder and back muscles, which actions are substantially on the same pull axis, whereby the trigger is moved in an entirely axial direction to fire the bow without generating sideways or other deflection forces which would impair shooting accuracy. 
   SUMMARY OF THE INVENTION 
   The above and further objects hereinafter becoming evident have been attained in accordance with the present invention which, in one of its broad embodiments and as viewed and interpreted from the drawings herein, is defined as an archery bow breech structure having a body means with a bowstring keeper device mounted thereon, trigger means axially slidably mounted on said body means, spring means attaching said body means to a hand pull sling means whereby at a predetermined bowstring pull force, e.g., about 16 lbs for a hump pull of 52 lbs., of the sling means by the shooter a lost motion action will be initiated and said body means, said keeper device and said trigger means will essentially remain in position relative to the bowstring during said lost motion action while said sling means will start to move away axially therefrom and from said bowstring, wherein said trigger means is adapted to be pinched between the thumb and forefinger of the shooters hand which is pulling said sling means during said lost motion action, whereby said trigger means when so pinched will follow said sling means and hand, and wherein shoulder means on said trigger means is adapted either to engage or to disengage a portion of said keeper device as said trigger means is slid axially on said body means during said lost motion action whereby said bowstring will be released from said keeper device. The strength of the spring means tested is such as to require a pull of about 25–30 lbs. to compress the spring to ½ its relaxed length. 
   A very important aspect of the above summarized invention is that the shooters fingers (includes thumb) do not impart any significant longitudinal or firing pull to the trigger, but only grips the trigger on its sides. The actual pull of the trigger derives from and during the lost motion action generated by the pull force of the sling means by the shooters hand, arm, and mainly shoulder and back muscles. In other words, without the lost motion action, movement of the trigger means would have to result from longitudinal pulling of the trigger means by crooking the fingers, which of course, would generate unwanted lateral forces. With the present invention, the consequent sliding motion of the trigger means to its firing position necessarily is axial to the bowstring draw axis and results solely from the lost motion action. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be further understood from the following description and drawings wherein the various structures are not drawn to scale or relative proportions and are intended to illustrate the concepts inherent in the present invention, and wherein: 
       FIG. 1  is a side view, with portions broken away from clarity, of the present breech structure; 
       FIG. 2  is an end view taken along line  2 — 2  in  FIG. 1 ; 
       FIG. 3  is a rear view of the breech structure being pinched between a shooters thumb and forefinger, 
       FIG. 4  is a longitudinal cross-sectional view taken generally thru line  4 — 4  in  FIG. 2 ; 
       FIG. 5  is a longitudinal cross-sectional view taken generally thru line  5 — 5  in  FIG. 2 ; 
       FIG. 6  is a view as in  FIG. 4  showing a variation in the device structure; 
       FIG. 6A  is a cross-sectional view taken along line  6 A— 6 A in  FIG. 6 ; 
       FIG. 7  is a partially sectioned view taken generally along line  7 — 7  in  FIG. 6 ; 
       FIG. 8  is a view as in  FIG. 6  showing a further variation in device structure; 
       FIG. 8A  is a cross-sectional view taken along line  8 A— 8 A in  FIG. 8 ; 
       FIG. 9  is a view taken along line  9 — 9  in  FIG. 8 ; 
       FIG. 10  is a view as in  FIG. 4  showing the positions of the device components, the haft means and the trigger means at firing; 
       FIG. 11  is a longitudinal cross-section showing the use of a pinching device for use axially moving the trigger means; 
       FIG. 12  are bowstring pull force graphs for a conventional bow and for a compound bow, e.g., having a peak draw force of about 52 lbs.; 
       FIG. 13  is a top view of a preferred construction for the present breech; 
       FIG. 14  is a side view of the breech of  FIG. 13 ; 
       FIG. 15  is a longitudinal cross-section taken generally along line  15 — 15  in  FIG. 13 ; 
       FIG. 16  is distal end view of the isolated trigger slide taken along line  16 — 16  in  FIG. 13 ; 
       FIG. 17  is a longitudinal cross-sectional view as in  FIG. 15 , of a further variation of the present breech with the body (barrel) not cross-sectioned; 
       FIG. 18  is a top down view of the isolated body of the breech of  FIG. 17 ; 
       FIG. 19  is a top view of the distal portion of the trigger slide in cross-section in  FIG. 17 ; 
       FIG. 20  is a longitudinal cross-section as in  FIG. 15  of the distal end portion of another variation of the present breech; 
       FIG. 21  is a top down view of the body of the breech of  FIG. 20  showing only the relative position of the roller in dotted line; 
       FIG. 22  is a top down view of the trigger slide of  FIG. 20  showing the position of the roller arm retracting pin mounted thru the sides of the trigger slide; 
       FIG. 23  is a side view of a preferred structure of a bowstring keeper; 
       FIG. 24  is a bottom up view taken along line  24 — 24  of  FIG. 23 ; 
       FIG. 25  is an end on view taken along line  25 — 25  in  FIG. 24 ; 
       FIG. 26  is a side view, partially sectioned, of the keeper means of  FIG. 23  showing the use and positioning of a keeper loop; and 
       FIG. 27  is a bottom up view taken along line  27 — 27  in  FIG. 26 . 
   

   DETAILED DESCRIPTION 
   Referring to the drawings wherein equivalent structures in the various figures are generally numbered the same, and with particular reference to the claims herein, the present bow breech structure comprises body means  10  having an elongated outer surface portion  12 , a longitudinal pull axis  14 , a front portion  16  and a rear portion  18 . A segment  29  of a bow string keeper means, wherein the various parts thereof fall under the general numeral  20 , is shaped to provide a keeper notch  25  into which the bowstring is held during bowstring draw. Segment  29  is pivotally mounted on said front portion by pin  27  and is pivotal between a cocked position  22  and a firing position  24  ( FIG. 13 ). 
   A trigger slide means  26  is slidably mounted on said outer surface portion  12  of said body means and has a finger contact surface  28  adapted to be pinched between the shooters thumb  31  and forefinger  33 , or equivalent, when firing is intended. Cooperating first shoulder means  30  is provided on said trigger means and second shoulder means  32  is provided on said keeper means, wherein said trigger means is generally axially movable with respect to and independently of movement of said body means to a first axial position  34  wherein said keeper means can be moved to its cocked position, and further axially movable to a second axial position  36  to engage said first and second shoulder means and release said keeper means to its firing position. 
   A haft means  38  is mounted on said body means for hand pulling said body means along with a bowstring  40  held by said keeper means  20 , wherein said haft means is attached to said body means by a lost motion spring means  42  of increasing or constant reactive force and confined between third shoulder means  21  and fourth shoulder means  23 . This spring is selected to impart a desired lost motion action to said haft means at a preselected bowstring pull resistance whereby the relative axial positions of said bowstring, body means, keeper means and trigger means remain substantially fixed during said lost motion action until said trigger means is physically rearwardly moved on said body means by the shooter to said second axial position. 
   The present inventive concept of employing the combination of a keeper means structure and an axially movable trigger structure which can release the bowstring from the keeper means solely thru axial movement of the trigger means independently of any motion of the body means to which the keeper means is attached, allows the use of any of a large variety of shapes and configurations of the keeper means structure. 
   For example, in  FIGS. 4  thru  9  the keeper means structure employs a keeper segment  44  and roller  46  which are the equivalents of items  46  and  29  respectively of the aforesaid U.S. Pat. No. 6,173,706 B1. However, in  FIGS. 4–7  the trigger means or trigger slide  26  is affixed by a pin  48  to a roller support shaft  50  which is slidable in a bearing bore  52  in body means  10 . In these embodiments a light compression spring  54  is preferably employed to urge shaft  50  and trigger slide  26  forwardly on body  10  to prevent inopportune disengagement of roller  46  from keeper segment  44 . A slot  56  in body  10  allows pin  48  and trigger slide  26  to slide longitudinally of body  10  between cocked position  22  and firing position  24  ( FIG. 10 ). 
   In  FIGS. 8 and 9  trigger slide  26  is not affixed in position to any portion of the keeper means but rather is provided with a slot  58  in which the top portion  60  of roller support arm  62  can longitudinally slide as the arm is rotated on shaft  61  which is mounted in brackets  63  affixed to body  10 . In this embodiment, trigger slide  26  is completely free to slide on body  10  within the limits imposed by its engagement with portion  60  of arm  62  of the limits of slot  58 . Compression spring  54  urges stud  65  slidably in bore  66  and thus arm  62  and roller  46  toward the cocked position  22  of the keeper means and trigger slide. A trigger adjustment screw such as  64  is threadably mounted on the front portion  16  of body  10  and is a substantial equivalent of screw  60  in the aforesaid 6,173,706 B1 patent and can be used with any of the keeper embodiments shown. 
   Referring to  FIG. 11 , a gripping means  68  is provided with resilient fingers  70  having barbs  72  adapted to be brought by light finger squeeze pressure into engagement with complimentary barbs  74  on the trigger slide  26 . This gripping means may be used for impart a more positive sliding force to the trigger. It is noted that alternatively, slide  26  may be knurled or the like to enhance the frictional grip of the shooter, although no more than a light finger and thumb squeeze is seldom needed. 
   Referring to  FIG. 12 , the following explanation of the operation of compound bows will further elucidate the significance and uniqueness of the present invention. 
   Before attempting to understand the principles of operation and the advantages of the present release (trigger means), one must understand the technique used during the final draw and release of the bowstring as well as understand the force-draw curve of a compound bow. 
   The shooting technique is called “power archer”. With this technique a shooter continues to apply draw force to the bowstring, primarily with shoulder and back muscles, while he is aiming at the target, as opposed to simply holding and aiming. During this push and pull activity, the shooter pulls the conventional trigger to release the bowstring. This pushing and pulling tends to prevent creep and allows the shooter to hold more steadily on the target, thus resulting in higher scores. The major problem that occurs when the shooter anticipates pulling the trigger to release the bowstring is that he flinches or jerks which generates lateral forces on the bow and string and causes a poor shot. 
   Plots of the force-draw curve for a compound bow and conventional bow are shown in  FIG. 12 . There are three terms that should be noted in particular. The “hump”, the “valley” and the “wall”. The hump is the first phase of the draw which requires the greatest force, and the force then drops off into the valley. If a shooter attempts to further draw the bow, he is pulling against the wall. At this point the bow cams have run out of travel and the bowstring is pulling directly against heavy bow limbs that are difficult to bend without the leverage of the cams. However, it should be noted that the wall is not completely vertical. During the push and pull activity, the draw length can still be increased slightly because some of the bow&#39;s component parts are continuing to bend, stretch or move slightly. 
   Further to this explanation and to emphasize the difficulties inherent in trigger design with respect to compound bows, in the trigger or release design concept, for example, of the aforesaid U.S. Pat. No. 6,481,430 B1, the bowstring is attached to one end of the release and the shooters drawing hand is attached to the other end of the release. As pull force is applied, a spring inside the release begins to compress. After the spring is compressed by a given prescribed force, the shaft thru the spring plus the string keeper will move, allowing the string to be released. The problem with this design is that the spring setting must be higher than the hump force in order to prevent premature and dangerous release. To overcome this problem a hand-actuated lock is built into the release. This lock is actuated before starting to draw the bowstring and then it is released when the draw force is in the valley (full draw). With this lock design, the spring setting must be set slightly above the valley force. The term slightly is an ambiguous amount because the judgement of different archers and at different times makes it difficult to known if the force he is feeling on the string is in the bottom of the valley or up the wall or perhaps up toward the hump by a few pounds. 
   Stated another way, the potential problem which this condition creates is that if the spring setting is too low when the hand held lock is released, the bowstring will be released prematurely. To overcome this problem, the spring pressure must be set high enough to be sure of no premature release. This situation creates the problem of how high to set the spring tension. The higher the spring pressure setting the more difficult it is for the shooter to accurately aim, push and pull until the bowstring is released. Also, if the shooter decides that he does not want to shoot after he has reached full draw, the lock must be engaged before the bow can be let down without accidentally releasing the bowstring. 
   In applicants design however, when near maximum draw force is applied to the breech, only the lost motion spring compresses and not parts of the keeper or trigger move until the shooter pinches the trigger slide. The draw force which initiates the lost motion action can be set, by screwing bushing nut  35  further in or out of body  10 , at whatever force the shooter desires, but typically at the valley pressure (or force) or slightly lower without any chance of causing accidental release. There is not need for a locking mechanism and the bow can be let down at anytime as if the bowstring were being held with one&#39;s fingers. 
   To use the present release, after the lost motion spring pressure has been properly set, the string keeper is hooked onto the bowstring. Once the bow has been drawn to full draw and the lost motion action has begun, and while the aiming process is in progress, the trigger slide is lightly pinched between the thumb and forefinger of the pulling hand. As the push, pulling and aiming process continues during the lost motion period the pinched trigger slide will move rearwardly on body  10  until the bowstring is released. This process which results in firing only during the lost motion period ensures a near perfect axial pull at the motion of surprise release, without sideways deflection or jerking of the bowstring or other bow components. 
   In  FIGS. 13  thru  27 , structures which are the same as or the equivalent in function to those shown in  FIGS. 1–12  are numbered the same, where practical. It is noted that the general body or barrel structure  10 , spring means  42 , shaft portion  37 , bushing nut  35 , half means  38  and finger sling  80  which provide for the lost motion action  43  are substantially the same in all of the embodiments shown in the drawings. 
   Referring to the embodiment of  FIGS. 13–16  and to claim  6  herein the breech structure comprises body means  19  having an elongated outer surface portion  12 , a longitudinal pull axis  14 , a front (distal) portion  16  and a rear (proximal) portion  18 , bow string keeper means  20  mounted on said front portion and movable between a cocked position  22  and a firing position  24 , trigger means  26  slidably mounted on said outer surface portion  12  of said body means and having a finger contact surface  28 , cooperating shoulder means  30  on said trigger means and shoulder means  46  on said keeper means, said trigger means  26  being generally axially movable relative to and independently of said body means to a first axial positions  34  wherein said keeper means  20  can be moved to its cocked position  22 , and further axially movable to a selected axial position  36  to cause said first  30  and second shoulder means  46  to release said keeper means to its firing position  24 , and haft means  38  mounted on said body means  10  for hand pulling said body means along with a bowstring held by said keeper means, wherein said haft means  38  is attached to said body means by spring means  42  selected to impart a desired lost motion action  43  to said haft means  38  at a preselected bowstring draw force whereby the relative axial positions of said bowstring, body means, keeper means and trigger means remain substantially fixed during said lost motion action until said trigger means  26  is physically moved rearwardly on said body means  10  by the archer to said second axial position  36 . 
   In this embodiment the shoulder means, e.g., roller  30  is mounted on shaft  11  which is pressed into apertures in sides  13  and  15  of a bridge portion  17  protruding axially on the distal end  39  of the trigger slide  26 . A proximal surface  41  of portion  17  is in constant contact with a plunger  65  which is urged distally by compression spring  54  to thereby position roller  30  to the cocked position of the keeper structure. The machine screw  45  is threaded into the distal end of the body  10  and its head  47  limits the distal motion and position of roller  30  such that the contact tip or shoulder  82  of the keeper means  20  is positioned slightly to the proximal side of the roller axis  49  to provide a hair trigger. Gripping ridges  51  are shown on only portions of the trigger sleeve but, of course, can extend along the full length of sleeve  26 . 
   Referring to  FIGS. 17–19 , body  10  is provided at its distal end with upstanding supports  53  and  55  between which a roller arm  62  is pivotally mounted by pin  67 . This arm is inserted thru a slot  69  in the distal end  57  of sleeve  26 . An adjustment screw  71  sets the trigger sensitivity by limiting distal motion of sleeve  26 , arm  62  and shoulder means (roller)  30  with respect to contact shoulder  82 . Supports  53  and  55  slide thru slots  73  and  93  respectively in sleeve  26 . 
   Referring to  FIGS. 20–22 , supports equivalent in function to  53  and  55  pivotally support arm  62  at  67 . A pin  100  is pressed thru side portions  101  and  102  of the distal end of sleeve  26  and is nested in a recess in the lower end  103  of arm  62 . Retraction of sleeve  26  upon firing pivots arm  62  and roller to the firing position. 
   Referring to  FIGS. 23–27 , a most preferred keeper construction embodiment is shown, wherein the structure comprises a base  75  having a longitudinal axis  76 , a proximal end  77 , a distal end  78 , top surface  79 , a bottom surface  81 , and a keeper segment  44  extending longitudinally from said proximal end and providing a contact shoulder  82  downwardly facing, bowstring hooking wall means  83  extending generally downwardly from said bottom surface  81  and having a bowstring hooking surface  84  slanting longitudinally toward said proximal end  77  at an angle to said axis  76  of from about 20° to about 40° to provide a keeper notch  85 , said wall means  83  having a bottom edge  86  and being curved generally concavely in a distal direction to provide a distally opening cavity  87 , a keeper post  88  extending generally downwardly thru said cavity  87  from said bottom surface  86  and slanting longitudinally toward said proximal end  77  at an angle to said axis  76  of from about 2° to about 30°, and said base further having tether tie means  89  to which a keeper loop  90  can be attached. The contact shoulder  82  preferably is a sharp edge  92  and the tie means  89  preferably comprises a side-by-side pair of apertures extending thru said base from said bottom surface  81  to said top surface  79 . 
   The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications will be effected with the spirit and scope of the invention.