Patent Publication Number: US-9404705-B2

Title: Rotary cam release trigger device for a crossbow

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Provisional Patent Application Ser. No. 61/713,555 filed Oct. 14, 2012 by Ben Kennedy and entitled “Rotary Cam Release/Trigger device for a Crossbow” and Provisional Patent Application Ser. No. 61/727,726 filed Nov. 18, 2012 by Ben Kennedy and entitled “An Improved Rotary Cam Release/Trigger device for a Crossbow”. 
    
    
     FIELD OF INVENTION 
     This invention relates to a rotary cam release/trigger device for a crossbow. The present disclosure is directed to an archery crossbow trigger or bowstring release device. Particularly the present disclosure is directed to a trigger mechanism having a cam operated release, an improved dry-fire prevention mechanism, and a convenient spring operated safety release. For archery equipment and, more particularly, a crossbow, the bowstring release assembly provides control and consistency in the release of a bowstring. 
     FEDERALLY SPONSORED RESEARCH 
     None. 
     SEQUENCE LISTING OR PROGRAM 
     None. 
     BACKGROUND—FIELD OF INVENTION AND PRIOR ART 
     Background 
     Crossbows in general have been used for many years as a weapon for hunting, fishing, and for target shooting. Significant development of the crossbow has occurred to increase the force with which an arrow is shot, to increase shooting accuracy, and to make the crossbow safe. In general, the crossbow includes a stock incorporating a trigger mechanism for selectively holding and releasing a bowstring used to propel an arrow. 
     The trigger mechanism used to hold and release a bowstring should allow a user to easily hold a drawn bowstring in a cocked position while prohibiting the bowstring from inadvertently releasing from the cocked position. The trigger mechanism must, therefore, positively hold a drawn bowstring, allowing release only upon actuation of a trigger. Unfortunately, in many instances, crossbow trigger mechanisms do not incorporate safe and reliable release mechanisms which positively hold a drawn bowstring while allowing a smooth release to improve shooting accuracy. 
     Another important characteristic of a crossbow trigger mechanism involves the pressure and actuation characteristics of the trigger, affecting the smoothness and accuracy with which a drawn bowstring is released. The release characteristics of the trigger mechanism are therefore very important to the shooting accuracy and repeatability of a crossbow. 
     Problems Addressed: 
     As target and sport archery increases in popularity, several shortcomings of the standard archery equipment limit many users and lead to safety concerns for all. In order to improve the experience and safety, changes and improvements to the standard equipment in the areas of releasing the bowstring, having a convenient safety mechanism and preventing dry-fires are needed. Once a crossbow is properly configured in the regular position, the user may cock the crossbow in preparation for loading and firing a crossbow arrow or bolt via the bowstring. In general, the crossbow imparts a substantial amount of force in order to accurately propel a bolt with respect to any intended target. In order to store in the crossbow mechanism the energy needed to impart such force to the bolt or arrow, the user must draw the bowstring back along the stock to a distance extent sufficient to preload or “cock” the crossbow. This task can also be quite strenuous, generally requiring the user to generate a large amount of force. 
     A user may cock the crossbow via direct manual cocking. For example, a user that has sufficient strength may elect simply to hold the stock with one hand, and draw the bowstring backward along the stock to a sufficient distance extent with the other. Alternatively, a user with less inherent strength may cock the crossbow via indirect manual cocking. For example, a user may choose to employ an “assist device” such as a cord assembly. The cord assembly may include a cord and a pair of manual gripping handles disposed at opposite ends of the cord. Such a user may then use their feet to hold a crossbow pointed downward against the ground, couple the cord of the cord assembly to a bowstring of the crossbow, and then pull upward as necessary with both hands using the gripping handles. Either way, the manual cocking of a crossbow requires a user to generate considerable force, which can be a safety concern if dry-fire is not prevented or if the safety hammer is not engaged with the release. 
     A cocked crossbow embodies a great deal of stored energy. Such stored energy may be released in different ways. For example, a user can load an arrow or “bolt” onto a cocked crossbow and thereafter actuate an associated trigger mechanism, thus firing the bolt from the crossbow (i.e., energy release via transfer/conversion). For another example, a user may decide not to fire a bolt, but rather to “de-cock” the crossbow by reversing (e.g., in a safe, controlled fashion) the process by which the crossbow was cocked (i.e., energy release via dissipation). In most if not all instances, however, it will generally be important to prevent the crossbow from releasing such stored energy prematurely, or as a result of an accident. For example, while the crossbow is being moved during hunting, but prior to firing, it may be advantageous for the hunter or user to keep the crossbow fully cocked (e.g., for purposes of readiness), but unloaded (e.g., for purposes of safety and/or convenience), such that all a user would need to do to fire the crossbow, once the decision to do so is finally made, is to load a bolt onto the crossbow stock, and then actuate an associated trigger mechanism (e.g., by pulling a trigger), allowing the bowstring to move forward and outward of the trigger mechanism, thereby rapidly propelling the bolt away from the crossbow along the same forward direction. 
     Keeping the trigger mechanism in such an advanced state of readiness can tend to minimize both the total amount of time needed, as well as the total amount of physical effort required to be expended in actually firing the crossbow, once the decision is finally made to do so. Unfortunately, however, the same advanced state of firing readiness in the trigger mechanism can tend to leave the crossbow vulnerable to so-called “dry fire”, in which a cocked bowstring of the crossbow is unintentionally released prior to a bolt being loaded in the crossbow, such that the time and effort needed to cock the crossbow in the first place must now be repeated. Dry fire can occur in any number of situations, including, for example, situations in which the crossbow is dropped, or in which the trigger mechanism is mistakenly actuated (e.g., while the crossbow is being moved, stowed, or retrieved during hunting). 
     In order to protect against dry fire, modern crossbow designs may include a corresponding safety mechanisms. For example, a crossbow may include a stock, a trigger mechanism, and a stop mechanism. The stop mechanism may include an arm that may be biased (e.g., via spring-loading) toward movement in the counter clockwise direction, but is deflectable as necessary in the opposite rotational direction. The stop mechanism may further include a manually operable handle. During a process of cocking the crossbow, the bowstring is drawn along the stock toward the trigger mechanism. Reaching the position of the stop mechanism, the bowstring will tend, as it passes the arm, to displace the arm upward and away from the rearward directed path of the bowstring along the stock. Upon further drawing of the bowstring into the trigger mechanism and past the position of the stop mechanism to complete cocking of the crossbow, the arm, now no longer in contact with the bowstring, is urged (e.g., via the aforementioned spring load) or otherwise allowed to rotate downward again, such that the arm is caused to rest against the stock. The current rotary cam version by Kennedy now has a dry-fire prevention mechanism in an simple yet improved configuration and requires nearly full cooperation of the arrow into the trigger slot prior to release. 
     In firing operation of the crossbow (i.e., after the same has been cocked as described above), the dry fire prevention function of the stop mechanism is overridden. More particularly, a bolt may be loaded onto the crossbow by being moved backward along the stock along the direction, toward and into the trigger mechanism. In the process of being loaded onto the crossbow, a tail end of the bolt “displaces” the arm upwards and out of the rearward path of the bolt. Conventionally, at this time, and up until a moment of firing the bolt, the arm may be allowed to rest atop a longitudinal shaft of the bolt. Upon the trigger mechanism being actuated, the bowstring is released. Since the arm of the stop mechanism remains displaced away from a forward path of the bowstring and of the bolt along the direction, the stop mechanism of the conventional device presents no obstruction with respect to continued forward motion of the string and bolt. 
     The crossbow with a conventional release is further operable in a dry fire prevention mode, with respect to which the arm of the stop mechanism, and tends to rest against the stock of the crossbow. More particularly, after the crossbow has been cocked (but before the crossbow has been loaded with a bolt as described above) the trigger mechanism may be vulnerable to an inadvertent actuation, normally leading to an unintended release of the bowstring from the trigger mechanism. This can lead to disastrous results such as splitting the limbs and causing irreparable harm to the crossbow or worse to the user. 
     Conventionally, upon the now released bowstring moving forward to the position of the stop mechanism, the arm serves to “catch” the bowstring at a position along the stock just forward of the trigger mechanism. Thereafter, the arm further can cooperate with the stock to block any further forward motion of the bowstring. The user is now permitted to re-cock the bowstring by drawing the bowstring back into engagement with the trigger mechanism, or, alternatively, to carefully allow a full, but now gradual release of the bowstring by a) partially drawing the bowstring back toward the trigger mechanism, b) manually displacing the arm upward and away from the bowstring by pulling downward on the handle, and c) permitting the bowstring to move slowly forward again along the direction. Here, by limiting unintended discharge of the bowstring to a relatively small throw during dry fire, the stop mechanism provides a very important safety feature. However, even when working as intended, the stop mechanism in conventional releases not only still fails to prevent dry fire, but also requires the bowstring to be redrawn to at least some extent backward along the stock and back into engagement with the trigger mechanism to restore the crossbow to the fully cocked state. Accordingly, apparatus and methods for preventing unintended discharge of a trigger mechanism of an unloaded crossbow remain both desirable and necessary. 
     Prior Art 
     Many prior art bowstring release devices utilize a trigger mechanism that is actuated by the archer. U.S. Pat. No. 3,937,206 to Wilson (1976) discloses a bowstring release device having a pivotable trigger mechanism that initiates the bowstring release mode. A rope loop is attached to the housing of the release device and extends around the bowstring for engagement. The rope loop is hooked in a notch formed in a release wheel to hold the bowstring as it is drawn. A sear block bears against the release wheel and is held against movement by a trigger block, thus holding the release wheel in position for drawing the bowstring. When the archer pulls the trigger lever on the trigger block, the trigger block pivots to disengage from the sear block. The sear block is no longer able to hold the release wheel which rotates to allow release of the bowstring. U.S. Pat. No. 5,598,829 issued to Bednar (1997) is entitled Crossbow dry fire prevention device. It demonstrates a device for a crossbow a dry-fire prevention mechanism. device for use with a crossbow. The crossbow includes a trigger mechanism which may have a guide slot into which a bowstring is drawn and retained for firing. A pivotal string catch member is positioned relative to the trigger mechanism to selectively extend into a string catching position which will catch and retain the bowstring should it be released from the trigger mechanism without an arrow in a firing position in the crossbow. The string catch member may include an arrow contacting surface to engage an arrow positioned to be fired from the crossbow, wherein, movement of the arrow to the firing position causes the string catch member to be moved out of the string catching position. 
     U.S. Pat. No. 5,649,520 also issued to Bednar (1997) is entitled Crossbow trigger mechanism. It demonstrates a mechanism providing improved bowstring retention and release characteristics. The invention further provides a safe and reliable trigger mechanism which enhances accurate shooting with the crossbow. The trigger mechanism comprises a pivotal string release latch for releasably holding a bowstring in a drawn position. The rearward extending portion of the trigger applies force on the rearward extending portion of the rocker latch member to cause pivoting thereof for disengagement of internal components. It also features an integral sight adjustment system for use with a rear sight of the crossbow. U.S. Pat. No. 5,224,463 issued to Townsend (1993) is entitled Bowstring release assembly. This device comprises a housing that receives the operative components that facilitate bowstring release motion. A gear assembly initiates and actuates the release motion. A rack and a pinion form the gear assembly. A trigger operates the rack to translate within the housing. Additionally, a rope loop anchored to the housing may be provided to wrap around the bowstring and hook onto the peg for restraint. 
     Various bowstring other release devices have been developed in order to normalize the release motion. The mechanics of these devices is intended to provide uniformity and consistency from use to use. U.S. Pat. No. 4,860,720 issued to Todd (1989) discloses a bowstring release device with a pivotable trigger that operates to extend and retract a sleeve mounted on the housing. Shown are a pair of ball bearings are mounted in the housing on opposing sides of a slot that receives the bowstring. When the sleeve is in the extended position, the ball bearings are pressed firmly together and restrain the bowstring in the slot. The sleeve retracts when the trigger is pulled, allowing the ball bearings to separate and release the bowstring. U.S. Pat. No. 7,770,567 issued to Yehle (2010) shows a safety trigger for a crossbow. It comprises a caliper, a trigger mechanism, a safety mechanism, and a bolt sensor. The caliper retains or releases a bowstring. The trigger mechanism holds the caliper against its bias to retain the bowstring, or releases the caliper to release the bowstring and fire the crossbow. 
     U.S. Pat. No. 8,091,540 issued to Matasic, et al. (2012) entitled Crossbow was a crossbow that includes several typical trigger mechanisms to releasably engage a crossbow bowstring brought within the trigger housing. The crossbow further includes a trigger adapted to releasably engage the bowstring catch, the trigger being further adapted to be selectively actuated by a user so as to cause the trigger to release the bowstring catch, thereby causing the bowstring catch to release a crossbow bowstring. Other options are shown. U.S. Patent Publication No. 2011/0197869 by Matasic, et al. published in 2011 shows a crossbow having improved limbs, safety mechanisms and release mechanisms. The disclosure provides improved bows (e.g., crossbows and/or vertical bows). More particularly, the present disclosure provides advantageous bows having improved limbs, trigger releases, safety mechanisms and/or dry fire mechanisms. 
     Finally, the field of the present invention have several other devices that relate to crossbows. For examples, U.S. Pat. No. 5,884,614 entitled “Crossbow with improved trigger mechanism” issued in 1999 to Darlington et al; U.S. Pat. No. 6,205,990 entitled “Dry-fire prevention mechanism for crossbows” issued in 2001 to Adkins; U.S. Pat. No. 6,736,123 entitled “Crossbow trigger” issued in 2004 to Summers et al; U.S. Pat. No. 6,802,304 entitled “Trigger assembly with a safety device for a crossbow” issued in 2004 to Chang; and U.S. Patent Publication No. 2006/0144380 entitled “Crossbow” published in 2006 in the name of Kempf. 
     As far as known, and based on the search, there are no rotary cam release/trigger devices for a crossbow or the like. The improved location below the arrow and the increased cam interference with the dry fire mechanism serves as an added feature to secure the bowstring from being released without the presence of a knock or arrow. It is believed that this product is unique in its design and technologies. 
     SUMMARY OF THE INVENTION 
     This invention is a rotary cam release/trigger devices for a crossbow. Taught here are the ways the present invention provides a safe and reliable trigger mechanism which enhances accurate shooting with the crossbow. The trigger mechanism comprises a spring operated pivotal/rotary cam string release mechanism for releasably holding a bowstring in a drawn position. The string release latch is pivotable about a pivot point and has associated therewith a first sear surface. The spring operated trigger mechanism further includes a pivotal rocker latch member having a second sear surface which engages the cam pivot mechanism. The sear has an extended arm that engages a spring operated safety hammer release. Finally there is a dry-fire prevention pivot mechanism that engages an arrow when loaded to launch. When no arrow is present the dry-fire rocker engages the rotary cam mechanism and prevents the movement of the cam to release the bowstring. 
     The preferred embodiment of the rotary cam release/trigger devices for a crossbow is comprised of a spring operated pivotal cam string release mechanism for releasably holding a bowstring in a drawn position, the pivotal/rotary cam release latch is pivotable about a pivot point and has associated therewith a first sear surface; a pivotal rocker latch member having a second sear surface which engages the cam pivot mechanism; the pivotal sear which has an extended arm that engages a safety hammer release; the safety hammer release; a dry-fire prevention pivot mechanism that engages an arrow when loaded to launch; a linkage to a trigger pull; the trigger pull; and an encasement that essentially contains all the components and provides the structure to maintain the pivots and the structural continuity to the release device for mounting the release to the crossbow between the side rails and wherein the release device provides a safe and reliable trigger mechanism which enhances accurate shooting with the crossbow. 
     The newly invented rotary cam release/trigger devices for a crossbow may be manufactured at low volumes by very simple means and in high volume production by more complex and controlled systems. 
     OBJECTS AND ADVANTAGES 
     There are several objects and advantages of the rotary cam release/trigger devices for a crossbow. There are currently no known crossbow trigger or release devices known that are effective at providing the objects of this invention. 
     The use of the rotary cam release/trigger devices for a crossbow offers several advantages as listed herein: 
     Advantages and Benefits 
     
       
         
           
               
               
             
               
                   
               
               
                 Item 
                 Advantages 
               
               
                   
               
             
            
               
                 1 
                 Fast release 
               
               
                 2 
                 Full spring operated safety (dry fire &amp; safety hammer) 
               
               
                 3 
                 Easy location for reaching safety release with the user&#39;s hand 
               
               
                   
                 and/or fingers 
               
               
                 4 
                 Smooth bowstring to arrow path (no interference) 
               
               
                 5 
                 Fewer parts compared with traditional trigger/release 
               
               
                 6 
                 May be interchanged with existing trigger/release mechanisms 
               
               
                   
                 in crossbow units 
               
               
                 7 
                 OEM and Replacement Sales 
               
               
                   
               
            
           
         
       
     
     Finally, other advantages and additional features of the present rotary cam release/trigger devices for a crossbow will be more apparent from the accompanying drawings and from the full description of the device. For one skilled in the art of crossbows and bowstring release mechanisms, it is readily understood that the features shown in the examples with this product are readily adapted to other types of crossbow and archery trigger mechanisms and devices. 
    
    
     
       DESCRIPTION OF THE DRAWINGS—FIGURES 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the rotary cam release/trigger devices for a crossbow that is preferred. The drawings together with the summary description given above and a detailed description given below serve to explain the principles of the rotary cam release/trigger devices for a crossbow. It is understood, however, that the rotary cam release/trigger devices for a crossbow is not limited to only the precise arrangements and instrumentalities shown. 
         FIGS. 1  A through  1  D are sketches of the general rotary cam release/trigger devices for a crossbows. 
         FIGS. 2  A and  2  B are sketches of the preferred and alternative rotary cam release/trigger devices with components and features noted. 
         FIG. 3  is a sketch of a rotary cam release/trigger device with components and features shown from generally a top view. 
         FIG. 4  is a sketches of a trigger encasement of a rotary cam release/trigger devices with the components and features shown from generally a top view. 
         FIG. 5  are sketches of the device components and feature shown from generally a top view. 
         FIGS. 6  A and  6  B are prototype parts of the rotary cam release/trigger devices. 
         FIGS. 7  A and  7  D are views of the rotary cam release/trigger devices mounted onto a crossbow. 
         FIGS. 8  A through  8  D are example steps of the rotary cam release/trigger device as it operates to release a bow string. 
         FIGS. 9  A through  9  F and  FIGS. 10  A through  10  F are parts and sketches of prior art devices. 
     
    
    
     DESCRIPTION OF THE DRAWINGS—REFERENCE NUMERALS 
     The following list refers to the drawings: 
     
       
         
           
               
             
               
                 TABLE B 
               
             
            
               
                   
               
               
                 Reference numbers 
               
            
           
           
               
               
            
               
                 Ref # 
                 Description 
               
               
                   
               
               
                  30 
                 general rotary cam trigger with preferred dry fire/release 
               
               
                   
                 device for a cross bow 
               
               
                  30A 
                 alternative embodiment rotary cam trigger/release 
               
               
                   
                 device for a cross bow 
               
               
                  31 
                 sketch of device with improved dry fire 
               
               
                  31A 
                 sketch of alternative device with an original alternative 
               
               
                   
                 dry fire 
               
               
                  32 
                 rotary cam trigger concept 
               
               
                  34++ 
                 crossbow 
               
               
                  35 
                 sample rotary cam trigger/release with improved dry fire 
               
               
                  40 
                 trigger housing 
               
               
                  40A++ 
                 side rails of the crossbow 
               
               
                  40B 
                 mounting apertures (and alternatives apertures) housing 40 
               
               
                   
                 to rails 40A 
               
               
                  40C 
                 arrow slot 
               
               
                  41 
                 spring pocket at sear pocket area 
               
               
                  41A 
                 spring pocket at dry-fire pocket area 
               
               
                  41B 
                 spring pocket safety hammer pocket area 
               
               
                  42 
                 rotary cam pivot pin 
               
               
                  43 
                 dry fire pivot pin 
               
               
                  44 
                 safety hammer pivot pin 
               
               
                  45 
                 sear pivot pin 
               
               
                  46 
                 cam pocket, cam spring pocket and shelf 46A 
               
               
                  46A 
                 additional clearance at cam pocket for tension springs 
               
               
                   
                 92A/92B 
               
               
                  47 
                 dry fire pocket for improved dry fire location 
               
               
                  48 
                 safety hammer pocket 
               
               
                  49 
                 sear pocket 
               
               
                  49A 
                 stop pocket 
               
               
                  50 
                 spring operated, pivotal Sear 
               
               
                  50A 
                 aperture 50A for connecting (pin 50B and aperture 50A, etc.)  
               
               
                   
                 sear 50 to linkage 85 
               
               
                  50B 
                 Pin for connecting sear 50 to linkage 85 and linkage 85 to trigger 
               
               
                   
                 86 
               
               
                  51 
                 sear to cam finger (extension) 
               
               
                  52 
                 sear to safety hammer flat (on sear) 
               
               
                  52A 
                 safety hammer to sear flat (on safety hammer) 
               
               
                  53 
                 sear to cam interference flat (angled approximately 7-10 
               
               
                   
                 degrees back angle or counter clockwise off 12 o&#39;clock/ 
               
               
                   
                 0 degrees i.e. 350 to 353 cam to mate with sear) 
               
               
                  54 
                 sear pivot pin aperture 
               
               
                  55 
                 sear spring pocket 
               
               
                  60 
                 rotary cam - spring operated pivotal cam bowstring release 
               
               
                   
                 latch mechanism 
               
               
                  61 
                 cam notch on alternative embodiment for engaging dry fire 
               
               
                   
                 80 above arrow slot 
               
               
                  62 
                 cam ball with spring detent for safety hammer interface 
               
               
                  63 
                 cam to sear interference flat (angled approximately 7-10 
               
               
                   
                 degrees back angle or counter clockwise off 12 o&#39;clock/ 
               
               
                   
                 0 degrees i.e. 350 to 353 cam to mate with sear) 
               
               
                  64 
                 bow string slot and radius 
               
               
                  65 
                 cam pivot aperture 
               
               
                  67 
                 cam stop flat 
               
               
                  68 
                 spring retention posts 
               
               
                  69 
                 bowstring retaining claw(s) 
               
               
                  70 
                 safety hammer 
               
               
                  70A 
                 trigger spring pocket 
               
               
                  71 
                 safety hammer thumb extension 
               
               
                  72 
                 safety hammer pivot pin aperture 
               
               
                  73 
                 cam ball lobe on safety hammer 
               
               
                  74 
                 sear stop extension leg 
               
               
                  80 
                 dry fire cam mechanism 
               
               
                  80A 
                 lobe from arrow or bolt shaft 
               
               
                  80B 
                 dry fire notch to interfere with cam pin 83 
               
               
                  82 
                 pivot aperture 
               
               
                  83** 
                 interference pin of rotary cam 60 with dry fire notch 80B 
               
               
                  84 
                 dry-fire spring pocket 
               
               
                  85++ 
                 linkage - sear to trigger pull 
               
               
                  85A++ 
                 means for connecting (pin and aperture, etc.) linkage 85 
               
               
                   
                 to sear 50 
               
               
                  85B++ 
                 means for connecting (pin and aperture, etc.) linkage 85 
               
               
                   
                 to trigger 86 
               
               
                  86++ 
                 trigger pull 
               
               
                  86A++ 
                 means for connecting (pin and aperture, etc.) trigger pull 
               
               
                   
                 86 to linkage 85 
               
               
                  88 
                 cross bow scope 
               
               
                  90 
                 bow string 
               
               
                  91 
                 compression spring - for sear, safety hammer and dry fire 
               
               
                  92A 
                 heavy duty spring (preferred) - helical/extension/tension springs 
               
               
                  92B 
                 torsion spring (alternative option) 
               
               
                  93 
                 cam stop cushion 
               
               
                  94 
                 arrow 
               
               
                  95 
                 release device in fully cocked and ready position with all 
               
               
                   
                 stops in place 
               
               
                  96 
                 dry fire lobe (81) and arrow (94) are engaged and rotate 
               
               
                   
                 the dry fire (80) about pivot (43) disengaging pin (83) 
               
               
                  97 
                 rotation of dry fire 
               
               
                  98 
                 insertion of arrow or bolt (loading) 
               
               
                  99 
                 safety hammer (70) rotated about pin (44) and disengaging leg 
               
               
                   
                 (74) and sear flat (52) 
               
               
                 100 
                 rotation of safety hammer 
               
               
                 101 
                 trigger (86) and linkage (85) pulled to rotate sear (50) about 
               
               
                   
                 pin (45) which disengage reference points (sear 53, cam 63) 
               
               
                   
                 which releases cam (60) to rotate [from compression spring 
               
               
                   
                 92A] and thrust bowstring (90) against arrow (98) in slots 
               
               
                   
                 (cam 64 and housing 40C). cam (60) stops when cam flat (67) 
               
               
                   
                 engages cushion stop (93). 
               
               
                 102 
                 trigger motion compresses spring (91) 
               
               
                 103 
                 sear pivots 
               
               
                 104 
                 main trigger spring 92A contracts 
               
               
                 105 
                 rotary cam 60 rotates and aligns rotary cam bow string slot and 
               
               
                   
                 radius 64 with arrow slot 40C of trigger housing 40 
               
               
                 106 
                 bowstring 90 thrusts to release tension and engages arrow 94 
               
               
                 107 
                 arrow 94 launches 
               
               
                 110 
                 prior art parts 
               
               
                 111 
                 prior art parts 
               
               
                 112 
                 prior art sketch 
               
               
                 113 
                 prior art parts 
               
               
                 114 
                 prior art parts 
               
               
                 115 
                 prior art parts 
               
               
                 116 
                 prior art patents 
               
               
                 117 
                 prior art patents 
               
               
                 118 
                 prior art patents 
               
               
                 119 
                 prior art patents 
               
               
                 120 
                 prior art patents 
               
               
                 121 
                 prior art patents 
               
               
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     The present development is a rotary cam release/trigger devices for a crossbow. Particularly the present disclosure is directed to a trigger mechanism having a cam operated release, an improved dry-fire prevention mechanism, and a convenient spring operated safety release. For archery equipment and, more particularly, a crossbow, the bowstring release assembly provides control and consistency in the release of a bowstring. 
     The advantages for the rotary cam release/trigger devices for a crossbow  30  are listed above in the introduction. Succinctly the benefits are that the device:
           1  Fast release     2  Full safety (dry fire &amp; safety hammer)     3  Easy location for spring operated safety release by the user&#39;s hand or fingers     4  Smooth bowstring to arrow path (no interference)     5  Fewer parts compared to traditional release/triggers     6  May be interchanged with existing trigger/release mechanisms in crossbow units.     7  OEM and replacement sales       

     The preferred embodiment is a rotary cam release/trigger devices for a crossbow comprised of a spring operated pivotal cam string release mechanism for releasably holding a bowstring in a drawn position, the cam release latch is pivotable about a pivot point and has associated therewith a first sear surface; a pivotal rocker latch member having a second sear surface which engages the cam pivot mechanism; the pivotal sear which has an extended arm that engages a safety hammer release; a spring operated safety hammer release; an improved dry-fire prevention pivot mechanism that engages an arrow when loaded to launch; a linkage to a trigger pull; the trigger pull; and an encasement that essentially contains all the components and provides the structure to maintain the pivots and the structural continuity to the release device for mounting the release to the crossbow between the side rails and wherein the release device provides a safe and reliable trigger mechanism which enhances accurate shooting with the crossbow. 
     There is shown in  FIGS. 1-10  a complete description and operative embodiment of the rotary cam release/trigger devices for a crossbow. In the drawings and illustrations, one notes well that the  FIGS. 1-10  demonstrate the general configuration and use of this product. The various example uses are in the operation and use section, below. 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the rotary cam release/trigger devices for a crossbow  30  that is preferred. The drawings together with the summary description given above and a detailed description given below serve to explain the principles of the rotary cam release/trigger devices  30  for a crossbow  34 . It is understood, however, that the trigger device  30  is not limited to only the precise arrangements and instrumentalities shown. Other examples of trigger/release devices  30  and uses are still understood by one skilled in the art of crossbows and bowstring release mechanisms to be within the scope and spirit shown here. 
       FIGS. 1  A through  1  D are sketches of the general rotary cam release/trigger device  30  for a cross Bow  34 .  FIG. 1  A shows a sketch of the rotary cam trigger concept  32 .  FIG. 1  B shows a sketch of device  31  with the preferred tension spring  92 A.  FIG. 1  C shows the alternative embodiment  31 A.  FIG. 1  D shows a sample rotary cam trigger/release  35 . 
       FIGS. 2  A and  2  B are sketches of the preferred and alternative rotary cam release/trigger devices with components and features noted.  FIG. 2  A is the preferred embodiment. Components are showed in more detail in  FIG. 3 , below. As a general introduction: Firstly shown is the main trigger housing  40 . Secondly is the sear  50 . Thirdly is the rotary cam  60 . Fourthly, is a spring operated safety hammer  70 . Fifthly is the dry fire cam  80 . More component details are in  FIG. 3 . 
       FIG. 2  B is a sketch of an alternative embodiment of a rotary cam release/trigger device  30 A with most of the components and features noted. Firstly shown is the main trigger housing  40  with the spring pocket  41  for holding the compression spring  91  at the sear, the spring pocket  41 A for holding the compression spring  91  at the dry fire cam, the rotary cam pivot pin  42 , the dry-fire pivot pin  43 , and the safety hammer pivot pin  44 . Other recesses and pockets are the arrow slot  40 C, the cam pocket  46 , the dry-fire pocket or recess  47 , the safety hammer recessed area  48 , the sear pocket  49 , and the stop pocket  49 A for holding the stop cushion  93  (pocket and stop not shown in all the views). Secondly is the sear  50  with its pin aperture  54 , the sear to cam finger or extension  51 , the sear and safety hammer flat configuration or plateau  52 ,  52 A, the spring pocket  55 , and the cam interference point  53  [essentially angled about 7-10 degrees minus or from perpendicular to mate with the cam]. Thirdly is the rotary cam  60  with the cam notch  61  for the dry-fire cam  80 , the cam/ball detent  62  for holding and then releasing the trigger lobe  73 , the cam to sear interference point  63  [essentially angled opposite to the sear point  53 —about 7 degrees plus or past perpendicular, the bowstring slot and radius  64 , the cam pivot pin aperture  65 , the spring apertures  66  (not shown in this view), the cam stop flat  67  (not shown in this view), the alternative cam torsion spring  92 B and retention posts  68  (posts not shown in this view but shown elsewhere), and the bowstring retaining claw  69 . Fourthly, is the safety hammer  70  with the pivot pin aperture  72 , the thumb extension  71 , the cam ball lobe  73  (for interference with ball detent  62 ), and the sear stop extension leg  74  that mates with the sear flat  52 . Fifthly is the dry fire cam  80  with the pin aperture  82 , the lobe  80 A for the arrow shaft  94 , the spring pocket  84 , the second compression spring  91 , and the interference point  83  for securing the cam  60 . Sixthly are the linkage  85  and trigger pull  86  pivotally linked to each other at one end of the linkage  85  and the linkage  85  pivotally linked to the sear  50  at the end of the linkage opposite to the pull  86 . Seventhly and finally, the side rail  40 B (not shown here) mounting apertures  40 C and the bowstring  90  are demonstrated. 
       FIG. 3  is a sketch of a preferred embodiment of a rotary cam release/trigger device with components and features shown from generally a top view. Firstly shown is the main trigger housing  40  with the spring pocket  41  for holding the compression spring  91  at the sear, the spring pocket  41 A for holding the compression spring  91  at the dry fire cam, spring pocket  41 B for holding the compression spring  91  at the safety hammer, the dry fire cam the rotary cam pivot pin  42 , the dry-fire pivot pin  43 , the safety hammer pivot pin  44  and the sear pivot pin  45 . Other recesses and pockets are the arrow slot  40 C, the cam pocket  46 , a relief  46 A for the heavy tension spring  92 A, the dry-fire pocket or recess  47 , the safety hammer recessed area  48 , the sear pocket  49 , and the stop pocket  49 A for holding the stop cushion  93 , the mounting apertures  40 B and the spring pin  68  for mounting the cam release spring  68 . Secondly is the sear  50 . This shows the its pin aperture  54 , the sear to cam finger or extension  51 , the sear and safety hammer flat configuration or plateau  52 , the spring pocket  55 , and the cam interference point  53  [essentially angled about 7 to 10 degrees back angle minus or Counter Clockwise from perpendicular to mate with the cam flat  63 ]. Thirdly is the rotary cam  60  with the cam pin  83  for holding the dry-fire cam  80  at detent  80 B, the cam/ball detent  62  for holding and then releasing the trigger lobe  73 , the cam to sear interference point  63  [essentially angled opposite to the sear point  53 —about 7 to 10 degrees plus or past perpendicular, the bowstring slot and radius  64 , the cam pivot pin aperture  65 , the spring pin  68 , the cam stop flat  67 , the preferred spring  92 A on the retention posts  68  at each end (note that one is in an aperture of the housing  40  and the other in an aperture of the cam  60 —not shown in this view but shown elsewhere), and the bowstring retaining claw  69 . Fourthly, is a spring operated safety hammer  70  with the pivot pin aperture  72 , the thumb extension  71 , the cam ball lobe  73  (for interference with ball detent  62 ), the sear stop extension leg  74  that mates with the sear at flat  52 A, and the spring pocket  70 A for another spring  91 . Fifthly is the dry fire cam  80  with the pin aperture  82 , the lobe  80 A for the arrow shaft  94 , the spring pocket  84 , the second compression spring  91 , and the interference point  80 B for engaging the stop pin  83  on the cam  60 . Sixthly are the linkage  85  and trigger pull  86  pivotally linked to each other at one end of the linkage  85  and the linkage  85  pivotally linked to the sear  50  at the end of the linkage opposite to the pull  86 . One notes the linkage  85  is connected by a means  85 A to the sear  50  and to the trigger pull  86  by a connecting means  85 B,  86 A. Seventhly and finally, the side rail  40 B (not shown here) mounting apertures  40 C and the bowstring  90  are demonstrated. 
       FIG. 4  is a sketch of a trigger encasement  40  of a rotary cam release/trigger device with the components and features shown from generally a top view. Here shown is the main trigger housing  40  with the spring pocket  41  for holding the compression spring  91  at the sear, the spring pocket  41 A for holding the compression spring  91  at the dry fire cam, spring pocket  41 B for holding the compression spring  91  at the safety hammer, the dry fire cam the rotary cam pivot pin  42 , the dry-fire pivot pin  43 , the safety hammer pivot pin  44  and the sear pivot pin  45 . Other recesses and pockets are the arrow slot  40 C, the cam pocket  46 , a relief  46 A for the heavy tension spring  92 A, the dry-fire pocket or recess  47 , the safety hammer recessed area  48 , the sear pocket  49 , and the stop pocket  49 A for holding the stop cushion  93 , the mounting apertures  40 B and the spring pin  68  for mounting the cam release spring  68 . 
       FIG. 5  are sketches of the device components and feature shown from generally a top view. Included is the sear  50 . This shows the its pin aperture  54 , the sear to cam finger or extension  51 , the sear and safety hammer flat configuration or plateau  52 , the spring pocket  55 , and the cam interference point  53  [essentially angled about 7 degrees minus or from perpendicular to mate with the cam]. Next is the rotary cam  60  with the cam pin  83  for holding the dry-fire cam  80  at detent  80 B, the cam/ball detent  62  for holding and then releasing the trigger lobe  73 , the cam to sear interference point  63  [essentially angled opposite to the sear point  53 —about 7 degrees plus or past perpendicular, the bowstring slot and radius  64 , the cam pivot pin aperture  65 , the spring pin  68 , the cam stop flat  67 , the preferred spring  92 A on the retention posts  68  at each end (note that one is in an aperture of the housing  40  and the other in an aperture of the cam  60 ) (not shown in this view but shown elsewhere), and the bowstring retaining claw  69 . Further shown is the spring operated safety hammer  70  with the pivot pin aperture  72 , the thumb extension  71 , the cam ball lobe  73  (for interference with ball detent  62 ), the sear stop extension leg  74  that mates with the sear flat  52 , and the spring pocket  70 A for another spring  91 . In addition is the dry fire cam  80  with the pin aperture  82 , the lobe  80 A for the arrow shaft  94 , the spring pocket  84 , the second compression spring  91 , and the interference point  80 B for engaging the stop pin  83  on the cam  60 . Finally is the cam bump pad  93 . Not shown are the linkage  85  and trigger pull  86  shown above in  FIG. 3  or the side rail  40 B shown below in  FIG. 7 . 
       FIGS. 6  A and  6  B are prototype parts of the rotary cam release/trigger device  30 .  FIG. 6  A shows the rotary cam  60  with the cam pin location for pin  83  for the dry-fire cam  80 , the cam/ball detent  62  for holding and then releasing the trigger lobe  73 , the cam to sear interference point  63  [angled opposite to the sear point  53 —about 7 degrees plus or past perpendicular, the bowstring slot and radius  64 , the cam pivot pin aperture  65 , the spring posts to hold the spring pins  68 , and the cam stop flat  67 .  FIG. 6  B shows the sear  50 , the safety hammer  70 , the dry fire cam  80 , the cam stop cushion  93 , and the spring  91 . The other features were described in Paragraph  2 , above. 
       FIGS. 7  A and  7  D are views of the rotary cam release/trigger device  30  mounted onto a crossbow  34 .  FIG. 7  A shows the trigger  86  and the scope  88 .  FIG. 7  B and FIG.  7  C show the scope  88 , the trigger housing  40 , and the crossbow side rails  40 A, between which the housing  40  is mounted with the apertures  40 C and fasteners.  FIG. 7  D shows the crossbow  34 , trigger  86 , the housing location  40  and the scope  88 . 
       FIGS. 8  A through  8  D are example steps of the rotary cam release/trigger device  30  as it operates to release a bow string  90  of the crossbow. These operational steps are described below in the operations section. 
       FIGS. 9  A through  9  F and  FIGS. 10  A through  10  F are parts and sketches of prior art devices. Here in the  FIG. 9  are shown: prior art parts  110 , prior art parts  111 , prior art parts  112 , prior art parts  113 , prior art parts  114 , prior art parts  115 , prior art parts  116 , prior art parts  117 , prior art parts  118 , prior art parts  119 , prior art parts  120 , and prior art parts  121 . One skilled in the art of trigger devices can readily see the improvements and fewer parts with the Kennedy rotary cam release/trigger devices for a crossbow. 
     Various materials may be utilized in the manufacturing of the rotary cam release/trigger device  30  for a crossbow  34 . As an example and not as a limitation, the components may be of various machined or cast metals including steel, steel alloys, stainless steel, composite materials including various plastics, both reinforced and virgin resins. The plethora of various materials are anticipated fully in the spirit and scope of the invention presented here. Also, the rotary cam actuation springs  92 A,  92 B may be a variety of compression or torsion springs as desired for the speed and smoothness of the cam action. 
     The details mentioned here are exemplary and not limiting. Other specific components and manners specific to describing a rotary cam release/trigger device  30  for a crossbow  34  may be added as a person having ordinary skill in the field of crossbows and bowstring release mechanisms and their uses well appreciates. 
     Operation of the Preferred Embodiment 
     The rotary cam release/trigger device  30  for a crossbow has been described in the above embodiment. The manner of how the device operates is described below. One notes well that the description above and the operation described here must be taken together to fully illustrate the concept of the rotary cam release/trigger device  30  for a crossbow. The preferred embodiment of the rotary cam release/trigger device  30  for a crossbow is comprised of a spring operated pivotal cam string release mechanism for releasably holding a bowstring in a drawn position, the cam release latch is pivotable about a pivot point and has associated therewith a first sear surface; a pivotal rocker latch member having a second sear surface which engages the cam pivot mechanism; the pivotal sear which has an extended arm that engages a safety hammer release; a spring operated safety hammer release; a dry-fire prevention pivot mechanism that engages an arrow when loaded to launch; a linkage to a trigger pull; the trigger pull; and an encasement that essentially contains all the components and provides the structure to maintain the pivots and the structural continuity to the release device for mounting the release to the crossbow between the side rails and wherein the release device provides a safe and reliable trigger mechanism which enhances accurate shooting with the crossbow. 
     The rotary cam release/trigger device  30  for a crossbow  34  is placed into a crossbow  34  somewhat similar to a conventional trigger/release mechanisms. The device  30  is contained within the housing  40 . That housing and all the contents secured within is placed between the side rails  40 A of the crossbow  34 . The mounting apertures  40 B of the housing  40  are aligned with the apertures in the side rails  40 A. Then the fasteners releasably yet rigidly secure the housing  40  between the side rails  40 A. 
     The operation of device  30  is significantly different. The rotary cam release/trigger device  30  for a crossbow  34  functions as shown in  FIGS. 8  A through  8  D. These figures are example steps of the rotary cam release/trigger device  30  as it operates to release a bow string  90 .  FIG. 8  A shows the release device  30  in fully cocked and ready position with all stops in place—Action/start position  95 .  FIG. 8  B shows dry fire lobe  81  and arrow  94  engaged and the cam lobe  80 A urges and rotates dry fire  80  about pivot  43  disengaging cam pin  83 —Action  96 . Shown here is the rotation of dry fire—Action  97  due to the movement and insertion of arrow  94  (loading) against the lobe  80 A—Action  98 .  FIG. 8  C shows the safety hammer  70  rotated about pin  44  and disengaging leg  74  and the sear flat  52 —Action/position  99 . Here is shown the rotation of safety hammer—Action  100 . Finally,  FIG. 8  D shows trigger  86  and linkage  85  pulled to rotate sear  50  about pin  45  which disengages sear  50  and cam  60  at shown reference points (sear  53 , cam  63 ). This then releases cam  60  to rotate [from torsion spring  92 A] and thrust the bowstring  90  against the arrow  94  in slots (cam  64  and housing  40 C). Again, please note the relationship of the bowstring  90  and the retention claw  69 . Cam  60  stops when cam flat  67  engages cushion  93 —Action  101 . As all this occurs, the trigger motion compresses sear spring  91 —Action  102 ; the sear pivots—Action  103 ; main trigger spring  92 A contracts—Action  104 ; rotary cam  60  rotates and aligns rotary cam bow string slot and radius  64  with arrow slot  40 C of trigger housing  40 —Action  105 ; Bowstring  90  thrusts to release tension of string and engages arrow  94 —Action  106 ; and arrow  94  launches—Action  107   
     With this description it is to be understood that the rotary cam release/trigger device for a crossbow  30  is not to be limited to only the disclosed embodiment of product. The features of the rotary cam release/trigger device  30  for a crossbow are intended to cover various modifications and equivalent arrangements included within the spirit and scope of the description. 
     While certain novel features of this invention have been shown and described and are pointed out in the annexed claims, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention. Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. 
     Unless they are defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which these inventions belong. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present inventions, the preferred methods and materials are now described above in the foregoing paragraphs. 
     Other of the embodiments of the invention are possible. Although the description above contains much specificity, these should not be construed as limiting the scope of the invention, but as merely providing illustrations of some of the presently preferred embodiments of this invention. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the inventions. It should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed inventions. Thus, it is intended that the scope of at least some of the present inventions herein disclosed should not be limited by the particular disclosed embodiments described above. 
     The terms recited in the claims should be given their ordinary and customary meaning as determined by reference to relevant entries (e.g., definition of “plane” as a carpenter&#39;s tool would not be relevant to the use of the term “plane” when used to refer to an airplane, etc.) in dictionaries (e.g., widely used general reference dictionaries and/or relevant technical dictionaries), commonly understood meanings by those in the art, etc., with the understanding that the broadest meaning imparted by any one or combination of these sources should be given to the claim terms (e.g., two or more relevant dictionary entries should be combined to provide the broadest meaning of the combination of entries, etc.) subject only to the following exceptions: (a) if a term is used herein in a manner more expansive than its ordinary and customary meaning, the term should be given its ordinary and customary meaning plus the additional expansive meaning, or (b) if a term has been explicitly defined to have a different meaning by reciting the term followed by the phrase “as used herein shall mean” or similar language (e.g., “herein this term means,” “as defined herein,” “for the purposes of this disclosure [the term] shall mean,” etc.). References to specific examples, use of “i.e.,” use of the word “invention,” etc., are not meant to invoke exception (b) or otherwise restrict the scope of the recited claim terms. Other than situations where exception (b) applies, nothing contained herein should be considered a disclaimer or disavowal of claim scope. Accordingly, the subject matter recited in the claims is not coextensive with and should not be interpreted to be coextensive with any particular embodiment, feature, or combination of features shown herein. This is true even if only a single embodiment of the particular feature or combination of features is illustrated and described herein. Thus, the appended claims should be read to be given their broadest interpretation in view of the prior art and the ordinary meaning of the claim terms. 
     Unless they are otherwise indicated, all numbers or expressions, such as those expressing dimensions, physical characteristics, etc. used in the specification (other than the claims) are understood as modified in all instances by the term “approximately.” At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the claims, each numerical parameter recited in the specification or claims which is modified by the term “approximately” should at least be construed in light of the number of recited significant digits and by applying ordinary rounding techniques.