Caliper type bow string release having push/pull trigger and automatic alignment and locking features

Abstract

A caliper type bow string release includes a reversible trigger which is operable selectively in either the push fire mode or the pull fire mode. The caliper jaws of the release include automatic alignment and locking features. Movement of the string into the release mechanism engages the automatic locking mechanism and closes the release into a string retaining position until the release is fired by activation of the trigger. A complex cam surface is provided on the actuator for permitting incremental linear adjustment of the trigger force.

1. A bow string release mechanism having a housing and a two-way trigger mounted in the housing, a sear assembly for selectively holding a bow string and for releasing the bow string upon actuation of the trigger, the bow string release mechanism including an actuator movable between a sear locking position and a sear releasing position for permitting movement of the sear assembly between a closed, string retaining position and an opened, string releasing position, respectively, and said trigger for controlling the actuator, the trigger and actuator being carried in the housing, the trigger further comprising:
 a. an elongated stem having one end extending outwardly of the housing and an opposite end;  
 b. an actuator engaging element on the stem, wherein the actuator engaging element is positioned on the stem intermediately of the opposite stem ends, and wherein the stem is adapted for rocking movement relative to the actuator engaging element; and  
 c. a mount for mounting the stem and the actuator engaging element for relative movement with respect to the housing in both a forward and a reverse direction, the actuator being responsive to each movement for activating the sear assembly to permit movement of the sear assembly from the closed, string retaining position to the opened, string releasing position:  
 d. wherein the actuator comprises a shaft mounted for axial movement relative to the housing and wherein the actuator engaging element is a through channel in the trigger stem and adapted for receiving the actuator shaft, the through channel having opposite outer edges disposed in axially spaced apart relationship along the axis of the actuator shaft, the through channel further including a shaft engaging element intermediately of the opposite outer edges, the channel opening at the outer edges being of a larger opening than the clearance between the shaft and the shaft engaging element, whereby the trigger stem is adapted to rock in a forward and reverse direction about the shaft in a plane of the axis of the shaft.  
 
     
     
       2. The release mechanism of  claim 1 , wherein the channel is wider at the outside edges and narrower therebetween to form a double V. 
     
     
       3. The release mechanism of  claim 1 , further comprising a selector associated with the trigger stem for selectively restricting the trigger stem movement to either the forward or the reverse direction, the selector including means for selectively restricting the rocking action of the trigger stem relative to the actuator shaft to either a forward action or a reverse action. 
     
     
       4. The release mechanism of  claim 3 , the shaft further including an abutment in communication with the trigger stem, whereby rocking movement of the trigger stem advances the trigger stem toward the abutment and generates axial movement of the actuator shaft. 
     
     
       5. The release mechanism of  claim 4 , wherein the selector further includes a stop member adapted to be selectively positioned in abutting engagement with the trigger stem either between the through channel and said one stem end or between the through channel and said other stem end, whereby the stem movements is limited by the stop for permitting the actuator to rock relative to the shaft for engaging the abutment and axially moving the shaft. 
     
     
       6. The release mechanism of  claim 4 , further including means for adjusting the position of the abutment relative to the shaft for controlling the rocking stroke of the trigger stem. 
     
     
       7. A bow string release mechanism having a sear assembly including a pair of pivotable jaws having a string retaining notch therein for selectively holding a bow string and for releasing the bow string upon actuation of a trigger, the bow string release mechanism including an actuator shaft movable between a jaw engaging and locking position and a jaw disengaging and releasing position for permitting movement of the jaws between an abutting, closed, string retaining position and a separated, opened, string releasing position, respectively, and a trigger for controlling the position of the actuator shaft, the trigger mounted in a housing including a handle portion adapted to be placed in the palm of the hand and gripped by the fingers with the trigger adapted to be engaged by the thumb, the trigger comprising:
 a. an elongated stem having one end extending outwardly of the housing;  
 b. an actuator engaging element on the stem;  
 c. a mount for mounting the stem and the actuator engaging element for relative movement with respect to the housing in both a forward and a reverse direction, the actuator being responsive to each movement for activating the sear assembly to permit movement of the sear jaws from the abutting, closed, string retaining, position to the separated, opened, string releasing, position; and  
 d. a selector associated with the trigger for selectively restricting the trigger movement to either the forward or the reverse direction, when engaged by the thumb.  
 
     
     
       8. The release mechanism of  claim 7 , wherein the actuator shaft is mounted for axial movement relative to the housing and wherein the actuator engaging element is a through channel in the trigger stem and adapted for receiving the actuator shaft, the through channel having opposite outer edges disposed in axially spaced apart relationship along the axis of the actuator shaft, the through channel further including a shaft engaging element intermediately of the opposite outer edges, the channel opening at the outer edges being of a larger opening than the clearance between the shaft and the shaft engaging element, whereby the trigger stem is adapted to rock in a forward and a reverse direction about the shaft in a plane of the axis of the shaft, the shaft further including an abutment in communication with the trigger stem, whereby rocking movement of the trigger stem advances the trigger stem toward the abutment and generates axial movement of the actuator shaft. 
     
     
       9. The release mechanism of  claim 8 , the selector further comprising means for selectively restricting the rocking action of the trigger stem relative to the actuator shaft to either a forward action or a reverse action, and a stop member adapted to be selectively positioned in abutting engagement with the trigger stem either between the through channel and said one stem end or between the through channel and said other stem end, whereby the stem pivots about the stop for permitting the actuator to rock relative to the shaft for engaging the abutment and axially moving the shaft. 
     
     
       10. The release mechanism of  claim 8 , wherein the channel is wider at the outside edges and narrower therebetween to form a double V. 
     
     
       11. The release mechanism of  claim 10 , wherein including means for adjusting the position of the abutment relative to the shaft for controlling the rocking stroke of the trigger stem. 
     
     
       12. The release mechanism of  claim 11 , further including biasing means associated with the actuator for urging the actuator into a position for maintaining the sear assembly in the closed position. 
     
     
       13. The release mechanism of  claim 12 , wherein the sear jaws are mounted for full rotation relative to the housing. 
     
     
       14. A bow string release mechanism having a sear assembly movable between a closed, string retaining position and an opened, string releasing position, an actuator associated with the sear assembly for selectively engaging and maintaining the sear assembly in the closed, string retaining, position, the actuator responsive to a movable trigger to disengage the sear assembly and permit the sear assembly to move from the closed, string retaining, position to the opened, string releasing, position, the sear assembly comprising:
 a. a support element;  
 b. a pair of opposed jaws pivotably mounted on the support element and adapted for pivotal movement into and out of abutting engagement with one another, each jaw having opposite outer ends, a forward end of the jaws including a string retaining notch which is closed for holding a string when the jaws are in abutting engagement and which is opened for releasing the string when the jaws are separated;  
 c. a rearward end of each jaw adapted for receiving the actuator for holding the jaws in the abutting, closed, string retaining, position;  
 d. the pivot point of each jaw being positioned intermediately of the opposite outer ends;  
 e. each jaw having a string receptive notch intermediately of the forward end of the jaw and the pivot point; and  
 f. one jaw including a tab projecting outwardly from the notch toward the opposing jaw and a tab-receptive socket in said other jaw for receiving the tab of the opposing jaw to assure alignment of the jaws when in the abutting, closed position.  
 
     
     
       15. The release mechanism of  claim 14 , wherein each jaw has a tab and a tab-receptive socket for the opposing jaw. 
     
     
       16. The release mechanism of  claim 15 , wherein said bearing means is an integral element on the jaws and comprises a projecting, arcuate bearing member on one jaw and a complementary arcuate, recessed channel in the opposite jaw. 
     
     
       17. The release mechanism of  claim 16 , wherein the center of the arcuate bearing member and the pivot points of the opposed jaws define a straight line when the jaws are in the closed position. 
     
     
       18. The release mechanism of  claim 17 , wherein each jaw includes an arcuate bearing member and a complementary arcuate, recessed channel for receiving the arcuate bearing member of the opposing jaw. 
     
     
       19. The release mechanism of  claim 14 , wherein each jaw further includes bearing means for assuring smooth, substantially simultaneous action of the jaws as they move from the closed, string retaining, position to the opened, string releasing, position. 
     
     
       20. A bow string release mechanism having a sear assembly movable between a closed, string retaining position and an opened string releasing position, an actuator associated with the sear assembly for selectively engaging and maintaining the sear assembly in the closed position, the actuator responsive to a movable trigger to disengage the sear assembly and permit the sear assembly to move from the closed string retaining position to the opened string releasing position, the sear assembly comprising:
 a. a support element;  
 b. a pair of opposed jaws mounted on the support element for pivotal movement into and out of abutting engagement with one another, each jaw having opposite outer ends, a forward end of the jaws including a string retaining notch which is closed for holding a string when the jaws are in abutting engagement and which is opened for releasing the string when the jaws are separated;  
 c. a rearward end of each jaw adapted for receiving the actuator for holding the jaws in the abutting, closed position;  
 d. the pivot point of each jaw being positioned intermediately of the opposite outer ends;  
 e. each jaw having a string receptive notch intermediately of the forward end of the jaw and the pivot point;  
 f. the string retaining notch of each jaw including a string engaging surface which is contoured to conform substantially to the outer periphery of the string when the jaws are in the closed position.  
 
     
     
       21. The release mechanism of  claim 20 , wherein the string engaging surface is contoured in both the radial and axial directions of the string. 
     
     
       22. The release mechanism of  claim 21 , wherein the radial contour is a concave surface. 
     
     
       23. The release mechanism of  claim 21 , wherein the axial contour is a convex surface. 
     
     
       24. A bow string release mechanism having a sear assembly movable between a closed, string retaining position and an opened, string releasing position, an actuator associated with the sear assembly for selectively engaging and maintaining the sear assembly in the closed, string retaining, position, the actuator responsive to a movable trigger to disengage the sear assembly and permit the sear assembly to move from the closed, string retaining, position to the opened, string releasing, position, the sear assembly comprising:
 a. an actuator engaging element on the sear assembly; and  
 b. the actuator having an adjustment surface which is selectively movable into and out of contact with the actuator engaging element in response to actuation of the actuator by the trigger, the adjustment surface being positionally adjustable relative to the actuator engaging element for calibrating the stroke required to release the string by actuation through the trigger, the adjustment surface being proportional to trigger movement such that an incremental change in position results in a predictable change in trigger stroke.  
 
     
     
       25. The release mechanism of  claim 24 , wherein the adjustment surface intercepts the axis of motion of the actuator at an inclined angle. 
     
     
       26. The release mechanism of  claim 25 , wherein the angular relationship between the adjustment surface and the actuator axis is progressively changing along the length of the adjustment surface. 
     
     
       27. The release mechanism of  claim 26 , wherein each angular portion of the adjustment surface is a linear element. 
     
     
       28. The release mechanism of  claim 26 , wherein the adjustment surface is a continuous curved surface. 
     
     
       29. The release mechanism of  claim 26 , wherein the adjustment surface defines a cam and the actuator element comprises a cam follower for engaging the cam, the actuator further including a biasing element for normally urging the actuator into engagement with the cam follower for maintaining the sear assembly in the closed, string retaining position, the trigger including a lever for applying a force to the actuator. 
     
     
       30. The release mechanism of  claim 27 , wherein the sear assembly further comprises:
 a. a pair of opposed jaws mounted for pivotal movement into and out of abutting engagement with one another wherein the jaws are in a closed, string retaining, position when in abutting engagement and an open, string releasing, position when not in abutting engagement, each jaw having opposite outer ends, a forward end of the jaws including a string retaining notch which is closed for holding a string when the jaws are in abutting engagement and which is opened for releasing the string when the jaws are separated;  
 b. a rearward end of each jaw adapted for receiving the actuator for holding the jaws in the closed, string retaining, position;  
 c. the pivot point of each jaw being positioned intermediately of the opposite outer ends; and  
 d. each jaw having a string receptive notch intermediately of the forward end of the jaw and the pivot point.  
 
     
     
       31. A bow string release mechanism having a sear assembly movable between a closed, string retaining position and an opened, string releasing position, an actuator associated with the sear assembly for selectively engaging and maintaining the sear assembly in the closed, string retaining, position, the actuator responsive to a movable trigger to disengage the sear assembly and permit the sear assembly to move from the closed, string retaining, position to the opened, string releasing position, the sear assembly comprising:
 a. a support element;  
 b. a pair of opposed jaws mounted on the support element for pivotal movement into and out of abutting engagement with one another, each jaw having opposite outer ends, a forward end of the jaws including a string retaining notch which is closed for holding a string when the jaws are in abutting engagement and which is opened for releasing the string when the jaws are separated;  
 c. a rearward end of each jaw adapted for receiving the actuator for holding the jaws in the abutting, closed position;  
 d. the pivot point of each jaw being positioned intermediately of the opposite outer ends;  
 e. a string retaining notch in each jaw intermediately of the forward end of the jaw and the pivot point;  
 f. the actuator having a jaw engaging adjustment surface which is selectively movable into and out of contact with the jaw in response to actuation of the actuator by the trigger, the adjustment surface being positionally adjustable relative to the jaw for calibrating the stroke required to release the string by actuation through the trigger, the adjustment surface being proportional to trigger movement such that an incremental change in position results in an incremental change in trigger stroke.  
 
     
     
       32. The release mechanism of  claim 31 , wherein the adjustment surface intercepts the axis of motion of the actuator at an inclined angle. 
     
     
       33. The release mechanism of  claim 32 , wherein the angular relationship between the adjustment surface and the actuator axis is progressively changing along the length of the adjustment surface. 
     
     
       34. The release mechanism of  claim 33 , wherein each angular portion of the adjustment surface is a linear element. 
     
     
       35. The release mechanism of  claim 33 , wherein the adjustment surface is a continuous curved surface. 
     
     
       36. The release mechanism of  claim 33 , wherein the adjustment surface defines a cam and each jaw includes a cam follower element for engaging the cam, the actuator further including a biasing element for normally urging the actuator into engagement with the jaws and for maintaining the jaws in the closed, string retaining position, the trigger including a lever for applying a force to the actuator. 
     
     
       37. The release mechanism of  claim 36 , wherein the trigger force required to fire the release is determined by the following formula: 
               cos   ⁢           ⁢   C     =       ⁢               (       cos   ⁡     (     90   -   C     )       ×   A     )     +               Fs   (     (       sin   ⁡     (     90   -     C   ×   A       )       +     (     sin   ⁢           ⁢   A   ×   G     )       )             G                   tan   ⁢           ⁢   C     =       ⁢         [     G   -   FsA     ]       [     A   +   FsG     ]       ⁢           when   ⁢           ⁢   contact   ⁢           ⁢   angle   ⁢           ⁢   adds   ⁢           ⁢   to               load   ⁢           ⁢   on   ⁢           ⁢   trigger   ⁢           ⁢   pull   ⁢           ⁢   pin                           tan   ⁢           ⁢   C     =       ⁢         [     FsA   +   G     ]       [     A   -   FsG     ]       ⁢           when   ⁢           ⁢   contact   ⁢           ⁢   angle   ⁢           ⁢   subtracts               from   ⁢           ⁢   load   ⁢           ⁢   on   ⁢           ⁢   trigger   ⁢           ⁢   pull   ⁢           ⁢   pin                       
       Tf   =       G   +   S     MA         
 
       where:
 C=contact angle between cam and follower sear elements  
 A=two times the force on a follower  
 Fs=coefficient of friction static on cam and followers  
 G=force on trigger pull pin due to loading and Fs  
 S=force applied by the return spring  
 MA=mechanical advantage of the trigger lever  
 Tf=trigger force required to fire the release.  
 
     
     
       38. A trigger for a bow string release mechanism, the trigger adapted for actuating the release by translating the trigger action to an actuator for activating a string retaining and release element, the trigger carried in a housing, the trigger comprising:
 a. a stem having one end in communication with the actuator and an opposite end extending from the housing for engagement by an archer; and  
 b. an engagement pad on said opposite end of the trigger, the engagement pad having an ergonomic surface for matching the thumb of the archer at full draw, the engagement pad further comprising four primary surfaces defining a forward, rearward and two side surfaces, where each of the surfaces are angled such that the pad feels and functions in the same manner whether engaged by the left thumb or the right thumb when the release is properly held in the hand of the archer.  
 
     
     
       39. The trigger of  claim 38 , wherein the stem includes a central axis and the four primary surfaces each intercept the axis at a common point. 
     
     
       40. The trigger of  claim 39 , wherein each of the four surfaces are truncated below the common point to form an additional surface substantially orthogonal to the axis. 
     
     
       41. The trigger of  claim 40 , wherein the additional surface is of a diamond shape. 
     
     
       42. A bow string release mechanism having a sear assembly for selectively holding a bow string and for releasing the bow string upon actuation of a trigger, the bow string release mechanism including an actuator movable between a sear locking position and a sear releasing position for permitting movement of the sear assembly between a closed, string retaining position and an opened, string releasing position, respectively, and a trigger for controlling the actuator, the trigger and actuator being carried in a housing, the trigger further comprising:
 a. an elongated stem having one end extending outwardly of the housing;  
 b. an actuator engaging element on the stem;  
 c. a mount for mounting the stem and the actuator engaging element for relative movement with respect to the housing in both a forward and a reverse direction, the actuator being responsive to each movement for activating the sear assembly to permit movement of the sear assembly from the closed, string retaining position to the opened, string releasing position; and  
 d. a selector associated with the trigger for selectively restricting the trigger movement to either the forward or the reverse direction.  
 
     
     
       43. The release mechanism of  claim 42  wherein the selector comprises a stop member adapted to be selectively positioned in engagement with the trigger stem adjacent one of said ends for restricting the movement of the stem relative to the housing. 
     
     
       44. The release mechanism of  claim 42 , further including biasing means associated with the actuator for urging the actuator into a position for maintaining the sear assembly in the closed position. 
     
     
       45. The release mechanism of  claim 42 , wherein the housing includes a handle portion adapted to be placed in the palm of the hand and gripped by the fingers, with the extended portion of the trigger stem extending outwardly from the handle in a position to be engaged by the thumb. 
     
     
       46. The release mechanism of  claim 45 , further including a thumb pad on said one end of the stem. 
     
     
       47. The release mechanism of  claim 42 , wherein the sear assembly comprises a pair of pivotable jaws having a string retaining notch therein, the actuator being adapted for engaging the jaws and maintaining them in abutting, string retaining relationship and the trigger adapted for withdrawing the actuator from the jaws for releasing them to a separated position for releasing the bow string. 
     
     
       48. The release mechanism of  claim 47 , wherein the sear jaws are mounted for full rotation relative to the housing. 
     
     
       49. The bow string release mechanism of  claim 42  further comprising an engagement pad on said opposite end of the stem, the engagement pad having an ergonomic surface for matching the thumb of the archer at full draw, wherein the engagement pad has a raised central surface adapted to fictionally engage the thumb of the archer for accommodating both a forward fire and a rearward fire motion.