Bowstring release assembly

A bowstring release assembly 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. The pinion is formed on a first portion of the peripheral surface of a rotary member which rotates in response to operation of the rack. A cam is formed on a second portion of the peripheral surface of the rotary member. The cam cooperates with a roller disposed on one end of a restraint assembly mounted on a pivot pin within the housing to allow bowstring release. A peg disposed on a second end of the restraint assembly engages the bowstring for restraint and pivots away upon actuation for release. A rope loop anchored to the housing may be provided to wrap around the bowstring and hook onto the peg for restraint.

TECHNICAL FIELD 
The present invention relates generally to archery equipment and, more 
particularly, to a bowstring release assembly that provides control and 
consistency in the release of a bowstring. 
BACKGROUND OF THE INVENTION 
The flight path of an arrow is influenced by many factors. Some factors, 
such as air currents, cannot be controlled by the archer. The major 
influences, however, on arrow trajectory are the physical actions of the 
archer. Accordingly, it is important for an archer to command the 
physically controllable factors to facilitate consistency and accuracy. 
The draw and release of the bowstring play an important part in defining 
the flight path of the arrow. After the arrow is nocked to the bowstring, 
the archer pulls the bowstring to a drawn position in preparation for 
firing. This places the bowstring in considerable tension. The archer then 
releases the bowstring by relaxing his grip. The bowstring is energized 
and responds by advancing instantaneously from the drawn position. This 
firing action propels the arrow. While this technique may be mastered for 
consistency through repetition, it can be appreciated that slight 
unintended and unnoticed adjustments or twitches during the release motion 
can significantly alter the desired trajectory of the arrow. 
Various bowstring 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. 
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 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. 4,860,720 to Todd discloses a bowstring release device with a 
pivotable trigger that operates to extend and retract a sleeve mounted on 
the housing. 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. 
Even though the prior art designs have provided more consistency in the 
release of the bowstring, they still have disadvantages. More 
particularly, since bowstring release devices are exposed to tremendous 
force in restraining the bowstring in the fully drawn position, they are 
subject to significant wear with use over time. As a result, the trigger 
must be continuously adjusted in order to maintain consistent operation. 
In addition, component wear introduces the opportunity for jerkiness in 
release motion. This substantially reduces the advantage of consistent 
bowstring release for which the device was designed. In extreme cases, the 
release device may fail, creating a hazardous situation. 
Accordingly, there remains a need to provide an improved bowstring release 
assembly that functions with precision for its intended purpose. The 
device should not require constant adjustment in order to maintain uniform 
operation. In addition, the bowstring release assembly should have a long 
service life. Thus, the assembly should be formed of durable components 
while being of simple design. 
SUMMARY OF THE INVENTION 
Accordingly, it is a primary object of the present invention to provide a 
bowstring release assembly that facilitates the consistent release of a 
drawn bowstring. 
It is another object of the present invention to provide a bowstring 
release assembly that is durable and has a long service life. 
Still another object of the present invention is to provide a bowstring 
release assembly that is of compact construction for easy handling when 
not in use. 
Another object of the present invention is to provide a bowstring release 
assembly with a trigger mechanism that allows smooth and easy actuation 
during the release mode. 
It is a further object of the present invention to provide a bowstring 
release assembly that improves firing accuracy by substantially 
eliminating extraneous movement by the archer to release the bowstring. 
Still another object of the present invention is to provide a bowstring 
release assembly that is easy and economical to manufacture. 
It is an additional object of the present invention to provide a bowstring 
release assembly that is capable of retaining a drawn bowstring under 
substantial tension in recurrent use without the need for constant 
adjustment. 
Additional objects, advantages and other novel features of the invention 
will be set forth in part in the description that follows and in part will 
become apparent to those skilled in the art upon examination of the 
following or may be learned with the practice of the invention. The 
objects and advantages of the invention may be realized and obtained by 
means of the instrumentalities and combinations particularly pointed out 
in the appended claims. 
To achieve the foregoing and other objects, and in accordance with the 
purposes of the present invention as described herein, an improved 
bowstring release assembly is provided. The assembly includes a housing 
that is of compact construction to facilitate ease in handling. The 
housing supports the operating components of the bowstring release 
assembly. 
The assembly includes means cooperating with the housing for engaging the 
bowstring for restraint and release. Preferably, the engaging means is a 
restraint assembly that cooperates with other components of the bowstring 
release assembly for operative use. A rope loop may be anchored to the 
housing and used to engage and restrain the bowstring during the drawing 
motion. While the rope loop is advantageously used to facilitate 
operation, the release assembly may be used with the bowstring directly 
engaging the restraint assembly. 
In an important aspect of the invention, a gear assembly is provided for 
actuating the engaging means to release the bowstring. It is well-known 
that gears efficiently transmit motion in a variety of operational 
settings. They offer precision and uniformity and thus provide a 
significant mechanical advantage in their working environment. It can thus 
be appreciated that the novel use of a gear assembly to actuate the 
release of the drawn bowstring furnishes superior consistency as compared 
with prior art designs. 
In the preferred embodiment, the gear assembly comprises a rack and a 
pinion. A trigger cooperates with the rack to initiate the release mode of 
the bowstring. When the trigger is in its cocked position, the bowstring 
release assembly is in the restraint mode, holding the bowstring in the 
drawn position. The trigger translates with the rack as it is pulled by 
the archer from its cocked position to initiate release motion. With this 
design, the trigger does not pivot about a fixed point to act as a lever 
as in most prior art designs. 
The preferred embodiment contemplates the trigger being formed integral 
with the rack. With this arrangement, the force required to actuate 
bowstring release is easily generated and efficiently transmitted. 
The pinion is formed on a first portion of the peripheral surface of a 
rotary member held within the housing. More specifically, gear teeth are 
formed on a portion of the rotary member. The rotary member is positioned 
within the housing so that the teeth of the pinion are disposed in mating 
engagement with the teeth of the rack. 
A cam is provided on a second portion of the peripheral surface of the 
rotary member. The cam is designed with a profile that cooperates with a 
cam follower to actuate release of the bowstring as the rotary member 
rotates in response to the initiating action of the trigger. 
The cam follower is a roller that is disposed on a first end of a restraint 
assembly. A peg that projects from the housing comprises a second end of 
the restraint assembly. The restraint assembly is mounted on a pin 
substantially centered between the roller and the peg. This mounting 
arrangement allows the restraint assembly to pivot between a restraint 
position and a release position. In the restraint position, the peg 
operates to hold the bowstring during drawing motion and maintains the 
bowstring in its fully drawn position. As the archer pulls the trigger to 
initiate the release mode, the peg remains in the restraint position until 
the roller engages the cam surface of the rotary member. At this instant, 
the peg pivots to the release position, thereby releasing the bowstring. 
The structural cooperation of the components of the bowstring release 
assembly defines a unique functional approach to addressing the 
disadvantages of prior art designs. More particularly, as broadly defined, 
the assembly includes means for initiating through translational motion 
the release of the bowstring. There is further provided means responsive 
to the translational initiating means for actuating the engaging means. 
The preferred embodiment of the invention contemplates that the actuating 
means operates through rotary motion to act upon the engaging means. 
From the description above, it can be appreciated that the initiating means 
and the actuating means in this structural combination include the gear 
assembly. Furthermore, in the preferred embodiment described above, the 
initiating means comprises the trigger cooperating with the rack and the 
actuating means comprises the pinion. 
The bowstring release assembly also includes an adjustment screw that is 
received within the housing and extends through a bore in the rack. The 
screw is operated to adjust the sensitivity of the trigger as desired. A 
return spring cooperates with and acts to bias the rack with the 
associated trigger to its cocked position. The housing also receives an 
anchor screw that attaches a wrist strap to the assembly. The wrist strap 
may be secured around the wrist to stabilize the bowstring release 
assembly during operative use. 
In operation, the release assembly is set in the restraint mode, with the 
trigger in the cocked position and the restraint assembly locked in the 
restraint position. With the bowstring held by the peg, it is drawn to its 
firing position. When ready to fire, the archer initiates the release mode 
by pulling the trigger. 
As the archer pulls the trigger, the rack translates within the housing. As 
a result of the mating engagement between the teeth of the rack and the 
teeth of the pinion, the rotary member is caused to rotate. The cam 
surface of the rotary member engages the roller of the restraint assembly 
at which time the roller looses restraining contact. At this instant, the 
tension of the bowstring is unopposed, allowing the bowstring to overcome 
the resistance offered by the peg of the restraint assembly. As the peg 
rotates about the pin from the restraining position to the release 
position, the bowstring is released to propel the arrow. 
Still other objects of the present invention will become apparent to those 
skilled in this art from the following description wherein there is shown 
and described a preferred embodiment of this invention, simply by way of 
illustration of one of the modes best suited to carry out the invention. 
As it will be realized, the invention is capable of other different 
embodiments and its several details are capable of modification in 
various, obvious aspects all without departing from the invention. 
Accordingly, the drawings and descriptions will be regarded as 
illustrative in nature and not as restrictive.

DETAILED DESCRIPTION OF THE INVENTION 
A preferred embodiment of the bowstring release assembly 10 according to 
the teachings of the present invention is shown in operative use in FIG. 1 
of the drawing. The inventive bowstring release assembly 10 provides 
consistent and uniform release motion during repeated use. Furthermore, 
the improved assembly 10 is compact and durable and thus has a long 
service life. 
In use, the bowstring release assembly 10 engages the bowstring 12 of a bow 
14 as it is drawn in preparation for launching an arrow (not shown). The 
archer firmly grasps the bow 14 with the appropriate hand while the other 
hand draws the bowstring 12 for firing as described by action arrow A. The 
drawing hand holds the bowstring release assembly 10 to functionally 
cooperate with the bowstring 12. 
For a right-handed compound bow 14 as shown in FIG. 1, the left-hand grasps 
the bow and the right hand pulls the bowstring 12 with the release 
assembly 10. The hand positions are reversed for left-handed compound 
bows. While the bowstring release assembly 10 is illustrated in use with a 
compound bow, the assembly functions effectively with other types of bows. 
It is important that the bowstring release assembly 10 is firmly held by 
the archer to take full advantage of its functional operation. To assist 
in stabilizing the release assembly 10 during operative use, it is mounted 
to a wrist strap 16 as is generally known in the art. The wrist strap 16 
typically has cooperating bands that ar secured together with a buckle 
assembly and/or a hook-and-loop fastener. The wrist strap 16 is attached 
to the bowstring release assembly 10 with a connector, such as an anchor 
screw 18. The anchor screw 18 is shown covered with a sleeve 19 in FIGS. 1 
and 2. The anchor screw is threadedly received in screw cavity 17 (see 
FIG. 3-5). 
Preferably, the wrist strap 16 is rotatably mounted to the bowstring 
release assembly 10. This allows the relative orientation to be reversed 
so that the assembly accommodates use with both right-handed and 
left-handed bows. The wrist strap 16 is wrapped around and secured to the 
archer's wrist in preparation for operative use. The wrist strap 16 not 
only enhances the consistent operation of the release assembly 10 but also 
secures it against loss or misplacement when not in use. This is 
particularly important when the archer is engaged in hunting activities in 
densely wooded areas. 
The bowstring release assembly 10 includes a housing 20 that receives the 
operational components. These components broadly include means 22 for 
engaging the bowstring for restraint and release. There is further 
included means 24 for initiating the release mode of the assembly 10. 
Finally, there is included means, in the form of a gear assembly 28, for 
actuating the engaging means 22 to release the bowstring 12 in response to 
the initiating means 24. 
The gear assembly 28 that functions to initiate and actuate the bowstring 
release motion. Gears have long been used to transmit motion generated by 
driving elements to driven elements. They have proven their functional 
value in many severe applications such as automobile transmissions and 
industrial machinery. When manufactured according to exact specifications, 
they offer operational precision through conjugate action and stand up to 
tremendous loads over extended periods of continuous use. Accordingly, it 
can be appreciated that the use of the gear assembly 28 in the inventive 
bowstring release assembly 10 provides superior consistency and improved 
uniform motion transmission as compared with known designs. 
As best shown in FIGS. 3-5, the gear assembly 28 preferably takes the form 
of a rack 30 that meshes with a pinion 32. The rack 30 is disposed for 
translational movement within the housing 20. The pinion 32 is formed on a 
first portion of the peripheral surface of a rotary member 34 mounted in 
the housing on a pivot pin 35. 
The rack 30 and pinion 32 are relatively positioned within the housing 20 
to allow cooperative meshing engagement between their respective teeth. 
Thus, efficient mechanical action occurs and uniform motion transmission 
results during operative use. Accordingly, the translation of the rack 30 
(see action arrow B in FIG. 4) causes the pinion 32 and thus the rotary 
member 34 to rotate as indicated by action arrow C. 
The bowstring release assembly 10 further includes a trigger 36 that 
cooperates with the rack 30 and is pulled by the archer (see FIG. 1 where 
the trigger is engaged by the index finger) to initiate the release mode. 
The trigger 36 translates in concert with the rack 30 as it initiates the 
release mode. Thus the trigger 36 does not pivot about a fixed point in 
operation as with most prior art bowstring release triggers. This 
advantageously improves the uniformity of trigger action and smooths 
overall operation for more accurate shooting. 
In the preferred embodiment, the trigger 36 is formed integral with the 
rack 30. The unitary construction provides a significantly stronger 
trigger mechanism as compared with prior art releases. Thus the 
opportunity for material wear failure is substantially reduced. In 
addition, the invention provides greater efficiency in the generation and 
transmission of release motion. 
The rotary member 34 further includes a cam 38 on a second portion of its 
peripheral surface. The rotary member 34 thus serves as the actuating 
means and responds to the initiation of the release mode by the trigger 
36. The cam 38 of the rotary member 34 is formed with a profile that 
cooperates with a cam follower to actuate the release of the bowstring 12 
during the release mode as is more fully described below. 
The cam follower is preferably a roller 40 disposed on one end of a 
pivotable restraint assembly 42. It can be appreciated from the following 
description that the restraint assembly 42 broadly comprises the engaging 
means 22 for the bowstring release assembly 10. 
Engagement of the bowstring 12 is effected by a peg 44 disposed on a second 
end of the restraint assembly 42. The peg 44 projects from the housing 20 
and acts to restrain the bowstring 12 when in its restraint position as 
the bowstring is drawn and held for firing. 
The restraint assembly 42 is mounted on a pivot pin 46 to secure the 
assembly to the housing 20. The pin 46 is substantially centered between 
the peg 44 and the roller 40. Thus, in operation, as the release mode is 
initiated, the roller 40 engages the cam surface 38 of the rotating rotary 
member 34. As this occurs, the peg 44 pivots away to allow the bowstring 
12 to be released for firing. 
As shown in the drawing, the bowstring release assembly 10 preferably 
includes a rope loop 48 that directly engages the bowstring 12 as it is 
drawn. The rope loop 48 is anchored to the housing 20 by a securing means 
such as rivet 49 (see FIG. 2) and is wrapped around the bowstring 12 prior 
to the drawing motion. The rope loop 48 is then hooked to the peg 44. With 
the peg 44 securely held in the restraint position by the rotary number 
34, the bowstring 12 is drawn with the release assembly 10 to the firing 
position. While the use of the rope loop 48 is most beneficial to the 
operation of the bowstring release assembly 10, the assembly may be used 
with direct engagement between the peg 44 and the bowstring 12 if desired. 
A return spring 50 is provided to bias the trigger 36 to the cocked 
position corresponding to the restraint position of the restraint assembly 
42. Thus, following the present firing cycle, the peg 44 is pivoted to the 
restraint position in preparation for the succeeding firing cycle. The 
return spring 50 urges the rack 30 forward and, through the cooperation of 
the pinion 32, rotates the rotary member 34 in the direction opposite to 
that occurring during actuation. In the restraint position, the roller 40 
is held against relative travel by the rotary member 34 (see FIG. 3). This 
locks the restraint assembly 42 in the restraint position until the 
trigger 36 is pulled from the cocked position. 
Advantageously, an adjustment screw 52 is provided to adjust the trigger 
force required to effect bowstring release motion. The screw 52 is 
received in an aperture 54 in the housing 20 and passes through a bore 56 
formed in the rack 30 (see FIGS. 3-5). The screw 52 includes an operable 
head 58 at a proximal end and a stop shoulder 60 at a distal end. The stop 
shoulder 60 abuts the edge of the rack 30 when the trigger 36 is in the 
cocked position. By manipulating the head 58 of the adjustment screw 52 
with the appropriate operating tool (e.g. screwdriver), the longitudinal 
position of the stop shoulder 60 is adjusted. As a result, the cocked 
position of the trigger is changed. Thus, the trigger stroke required to 
cause the release of the bowstring 12 may be adjusted. Accordingly, the 
adjustment of the screw 52 alters the sensitivity of the bowstring release 
assembly 10 as desired. 
The operation of the firing cycle utilizing the inventive bowstring release 
assembly 10 will now be described. The release assembly 10 is secured to 
the archers hand with the wrist strap 16. As stated above, the peg 44 is 
pivoted to the restraint position and the return spring 50 biases the 
trigger 36 to the cocked position. The rope loop 48 is wrapped around the 
bowstring 12 and hooked over the peg 44. The hand holding the release 
assembly 10 is retracted, drawing the bowstring 12 to the firing position. 
It can be appreciated that the tension in the drawn bowstring 12 creates a 
tremendous force on the peg 44. The bowstring 12 seeks to alleviate the 
tension through the release motion. However, uninitiated release is 
prevented due to the resistance force created by the stationary engagement 
of the roller 40 with the edge of the rotary member 34. Thus, the release 
of the bowstring 12 and firing of an arrow is under the strict control of 
the trigger 36. 
With particular reference to FIG. 2, when ready to fire, the archer grasps 
the trigger 36 and pulls to initiate the release mode as shown by action 
arrow D. The rack 30 translates in response to manipulation of the trigger 
36. This drives the pinion 32 and thus the rotary member 34 to rotate. As 
the rotary member 34 rotates, its cam surface 38 is presented for 
engagement with the roller 40. At this instant, the stored energy of the 
tensed bowstring 12 is released, forcing the peg 44 to pivot away from the 
restraint position (see action arrow E) to release the bowstring 12 for 
firing action according to action arrow F. 
In summary, numerous benefits result from employing the concepts of the 
present invention. Advantageously, the gear assembly 28 provides 
significant mechanical advantage for consistent and uniform release of the 
bowstring 12. The translational capability of the rack 30 provides smooth 
motion as the archer pulls the trigger 36 to initiate bowstring release. 
The rotary member 34 upon which the pinion 32 is formed rotates in 
response to the translational motion of the cooperating rack 30. The 
roller 40 of the restraint assembly 42 cooperates with the cam surface 38 
of the rotary member 34 to actuate bowstring release. The components 
cooperate efficiently to offer a well-balanced, reliable and durable 
bowstring release assembly 10. 
The foregoing description of a preferred embodiment of the invention has 
been presented for purposes of illustration and description. It is not 
intended to be exhaustive or to limit the invention to the precise form 
disclosed. Obvious modifications or variations are possible in light of 
the above teachings. The embodiment was chosen and described to provide 
the best illustration of the principles of the invention and its practical 
application to thereby enable one of ordinary skill in the art to utilize 
the invention in various embodiments and with various modifications as is 
suited to the particular use contemplated. All such modifications and 
variations are within the scope of the invention as determined by the 
appended claims when interpreted in accordance with breadth to which they 
are fairly, legally and equitably entitled.