ARROW DRAW CHECK FOR ARCHERY BOWS
United States Patent 3861051
A mirror is mounted for movement with an archery bow sight and is arranged to reflect to the eye of the archer the image of the tip of a drawn arrow in registry with an index mark on the mirror. Adjustment means interengages the mirror and sight mount for automatically adjusting the mirror angularly during vertical adjustment of the sight, to maintain said registration of the arrow tip and index mark at the eye of the archer throughout the range of the vertical adjustment of the sight.
US Patent References:
Bow sight
Bradley - December 1950 - 2534946
ARCHERY SIGHT
Duplechin - July 1970 - 3521362
ARCHERY BOW INCLUDING MIRROR TYPE SIGHTING DEVICE
Hill - August 1970 - 3524440
ARCHERY BOW SIGHT
Crosby - September 1970 - 3526037
ARCHERY BOW SIGHT
Heffer - February 1973 - 3715807
Bow sight
Bradley - December 1950 - 2534946
ARCHERY SIGHT
Duplechin - July 1970 - 3521362
ARCHERY BOW INCLUDING MIRROR TYPE SIGHTING DEVICE
Hill - August 1970 - 3524440
ARCHERY BOW SIGHT
Crosby - September 1970 - 3526037
ARCHERY BOW SIGHT
Heffer - February 1973 - 3715807
Application Number:
05/308270
Publication Date:
01/21/1975
Filing Date:
11/20/1972
View Patent Images:
Export Citation:
Primary Class:
International Classes:
F41G1/467; F41G1/00; F41G1/46
Field of Search:
33/265
Primary Examiner:
Rothberg, Samuel B.
Assistant Examiner:
Stearns, Richard R.
Attorney, Agent or Firm:
Olson, Oliver D.
Claims:
Having now described my invention and the manner in which it may be used, I claim
1. In combination with an archery bow sight supported on an elongated base for movement longitudinally thereof, a draw check comprising:
2. In combination with an archery bow sight mounted on a carriage supported on an elongated base for movement longitudinally thereof, a draw check comprising:
1. In combination with an archery bow sight supported on an elongated base for movement longitudinally thereof, a draw check comprising:
2. In combination with an archery bow sight mounted on a carriage supported on an elongated base for movement longitudinally thereof, a draw check comprising:
Description:
BACKGROUND OF THE INVENTION
This invention relates to the art of archery, and more particularly to a draw check by which to insure the repeated drawing of an arrow consistently to the same position relative to a bow.
Most archery bows are provided with a sight element which is adjustable vertically through a distance of 6 or more inches, in correspondence with the range capability of the bow, to provide proper trajectory of an arrow to a target.
It is the fundamental principal in archery that the arrow should be drawn back from the bow consistently to the same length, in order to achieve corresponding consistency of arrow speed and trajectory. Various means, referred to in the art as draw checks, have been provided heretofore to provide the archer with a visual check of the length to which the arrow has been drawn. However, all known forms of draw checks provided heretofore are mounted on a bow in a fixed position, while the sight element is adjustable vertically through a substantial range.
One such draw check comprises a wire mounted pivotally on the bow and arranged to engage an arrow a predetermined distance forwardly of the bow. When the arrow has been drawn to the proper distance, the wire falls downwardly from in front of the arrow, to give visual indication to the archer that the arrow has been drawn to the proper distance. A second form of draw check provided heretofore utilizes the metal tip of an arrow to complete an electric circuit of an indicator light mounted on the bow. Thus, when the arrow has been drawn to the proper distance, the metal tip thereof completes the electric circuit of the lamp. A third form of draw check provided heretofore comprises a mirror mounted on the bow at an appropriate angle to reflect to the eye of an archer the tip of a drawn arrow. The mirror is provided with an index mark with which the arrow tip is to be aligned, when the arrow has been drawn to the proper distance.
Accordingly, with the fixed draw checks of the prior art, the eye of the archer must be shifted by as much as 6 or more inches alternately to focus on the draw check and the sight. This not only introduces a disturbing factor to the archer, but it also contributes adversely to slow and inaccurate sighting.
SUMMARY OF THE INVENTION
In its basic concept, the draw check of this invention involves the mounting of a draw check mirror for simultaneous vertical movement with a bow sight and angular adjustment with respect to the axis of the sight, to maintain at the eye of an archer the image of a predetermined point on a drawn arrow in registry with an index mark on the mirror, throughout the range of a vertical adjustment of the sight.
It is by virtue of the foregoing basic concept that the principal objective of this invention is achieved; namely, to overcome the aforementioned disadvantages of prior draw checks.
Another important object of this invention is the provision of a draw check of the class described which is of simplified construction for economical manufacture and which is operable with precision throughout the range of adjustment of the bow sight.
The foregoing and other objects and advantages of this invention will appear from the following detailed description, taken in connection with the accompanying drawing of a preferred embodiment.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a fragmentary view in side elevation of an archer in ready position for shooting an arrow from a bow equipped with a vertically adjustable sight supporting a draw check embodying the features of this invention.
FIG. 2 is a fragmentary view in side elevation of the sight elevation adjustment mechanism and draw check illustrated schematically in FIG. 1.
FIG. 3 is a fragmentary plan view as viewed from the top in FIG. 2.
FIG. 4 is a fragmentary view in front elevation as viewed from the left in FIG. 2.
FIG. 5 is a fragmentary enlarged rear elevation of the draw check as viewed from the right in FIG. 2, portions being broken away to disclose details of internal construction.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1 there is illustrated a conventional form of archery bow 10 provided with a hand grip 12, an arrow rest (not shown) above the hand grip, and a draw string 14 with knocking point (not shown) for receiving an arrow 16.
The sight elevation adjustment mechanism illustrated is described in detail in my co-pending application entitled ELEVATION ADJUSTMENT MECHANISM FOR ARCHERY BOW SIGHTS, filed June 16, 1972 under Ser. No. 263,419. It includes an elongated arm 18 adapted to be mounted on the side of an archery bow. The forward end of the arm is connected to a bracket 20 which, in turn, is connected to the rear side of a vertically elongated base 22. The base includes a correspondingly elongated guide 24 of dove-tail cross section which slidably mounts a carriage 26 by means of a correspondingly shaped dove-tail groove. The carriage mounts a sight-supporting block 28, as by screws 30 and 32, for movement therewith.
The sight-supporting block is provided with a transverse bore which slidably receives a collar 34 for longitudinal movement therein. A tapped central bore in the collar adjustably supports an elongated, threaded sight-mounting rod 36. The rod extends through the block, and one projecting end thereof mounts an adjusting knob 38. The opposite projecting end of the rod mounts an archery bow sight 40 integrated with a bubble level 42 contained in a cylindrical housing 44 secured to and projecting from the rod.
The structural arrangement of the sight-supporting block assembly accommodates lateral adjustment of the sight relative to the block, by appropriate rotation of the adjusting knob. This lateral adjustment is a windage compensation adjustment, as will be understood.
A latch member 46 is mounted pivotally intermediate its ends for movement with the carriage 26. One end portion 48 of the latch member forms a finger button, while the opposite end portion 50 is bent outwardly away from the carriage and is formed with an arcuate notch arranged releasably to engage an elongated mircometer screw 52 mounted for axial rotation on the base 22 by means of a pair of spaced bearing members 54. One end of the screw is provided with a knurled knob 56 to facilitate its rotation. The rotational axis of the screw is disposed parallel to the line of movement of the carriage and sight-supporting block on the guide 24. Thus, rotation of the knob effects movement of the carriage, and hence the sight 40, along the length of the guide.
In the use of the elevation adjustment mechanism it is necessary that it be calibrated for the bow on which it is mounted. Thus, a strip 58 of paper is glued to a recess in the guide 24 and various test shooting are made at various ranges. The desired elevation adjustments for the various ranges then are marked on the paper in registry with an index marker 60 projecting from the carriage.
In accordance with this invention, a draw check mirror 62 is mounted for simultaneous vertical movement with the sight 40 and angular adjustment relative to the sight automatically during said vertical adjustment to maintain at the eye of an archer the image of a predetermined point on a drawn arrow in registry with an index mark 64 (FIG. 5) on the mirror, throughout the range of vertical adjustment of the sight.
In the embodiment illustrated, the draw check mirror is mounted in a retaining frame 66. A boss 68 projects laterally from the frame and secures firmly thereto one end of a laterally extending shaft 70. The shaft extends freely through a bearing 72 formed on a support plate 74. The plate is secured removably to the sight-supporting block 28 by means of the screw 30 which secures the block to the carriage. The screw extends through a laterally elongated slot 76 (FIG. 4) in the plate, the slot accommodating a degree of lateral adjustment of the plate and mirror, for alignment of the mirror with an arrow. In this regard, many bows are provided with a laterally adjustable arrow rest and hence it is desirable that the mirror also be similarly adjustable.
From a consideration of FIGS. 1 and 2 of the drawing, it will be apparent that, since the position of the drawn arrow 16 remains fixed relative to the bow 10, the angular disposition of the mirror 62 relative to the sighting axis 78 of the sight must be changed progressively as the sight is moved vertically along the guide 24, in order for the reflected image of the tip of the arrow be maintained in registry with the index 64 on the mirror, at the eye of the archer. In accordance with this invention, such angular adjustment of the mirror is made simultaneously and automatically as the sight is moved through its range along the guide.
In the embodiment illustrated, a sleeve 80 is mounted on the shaft 70 between the boss 68 and the bearing 72. Secured to the sleeve and projecting therefrom is an elongated cam follower arm 82. The outer end portion 82' of the arm is offset angularly toward the base 22 for sliding engagement with the operating surface 84' of an elongated cam plate 84. This plate is secured to the side of the base by means of attaching screws 86 which extend through openings in the cam plate and into threaded openings in the base. At least one of the screw openings in the cam plate, the lower screw opening 88 in the embodiment illustrated, is elongated arcuately to provide a degree of adjustment of the cam plate. This enables the draw check to be mounted upon a variety of types and sizes of archery bows and adjusted to accommodate the characteristics of the bow.
The sleeve 80 is secured releasably to the pivot shaft 70 of the mirror by such means as a set screw 90. Accordingly, the sleeve and shaft are adjustable rotationally relative to each other and secured in desired position of adjustment by the set screw. This accommodates angular adjustment of the mirror, as may be required for different bows.
Resilient means is provided for maintaining the cam-engaging portion 82' of the cam arm in engagement with the cam surface 84' of the cam plate. In the embodiment illustrated, such means is provided by a coil spring 92 which encircles the portion of the mirror shaft 70 projecting through the bearing 72. One end of the coil spring is secured to the shaft, as by engagement in a hole in the shaft. The opposite end of the spring abuts the support plate 74. The coil spring thus urges the shaft rotationally in the direction to maintain the cam arm in sliding engagement with the cam plate.
The operating surface 84' of the cam plate is contoured, relative to the longitudinal axis of the guide 24, to cause the mirror 62 to pivot progressively as the sight 40 moves vertically along the guide, to adjust the angle of the mirror relative to the sighting axis 78 of the sight, so as to maintain at the eye of an archer the image reflected from the mirror of a predetermined point on a drawn arrow 16 in registry with the index 64. This is best illustrated in FIG. 2 of the drawing by comaring the angular positions of the mirror relative to the sight axis in the full and broken line positions shown. Thus, in the full line position the angle of the mirror is such as to provide an angle a of reflection of the tip of the drawn arrow to the eye, the latter being located on the sighting axis 78 (FIG. 1). When the sight 40 has been lowered on the guide 24 to the broken line position, the point of engagement of the cam arm with the cam surface has caused the mirror to pivot counterclockwise to an angular position relative to the sight axis to provide the angle b of reflection of the arrow tip to the eye of the archer.
Accordingly, with the arrow maintained in properly drawn position and the archer's eye maintained in proper position relative to the bow, the reflected image of the tip of the arrow will be maintained in registry with the index 64 on the mirror, as viewed by the archer, throughout the range of vertical adjustment of the sight along the guide. Moreover, the distance between the sight and index mark on the mirror remains substantially constant throughout said range of adjustment. Since this distance is very short in relation to the distance from the sight to the eye of the archer, the amount of shifting of the eye alternately to view the sight and the index mark, is negligible.
It will be understood, of course, that when the sight is moved downward to the broken line position illustrated in FIG. 2, the entire bow assembly will be swung arcuately upward so that the sight once again is coincident with the line 78 of sight from the target to the eye of the archer.
In the embodiment illustrated, the operating surface 84' of the cam plate is slightly arcuate, having a radius of approximately 20 feet. Although the necessity of this curvature is not completely understood, it has been found that if the operating surface is formed as a straight line, the image of the arrow tip is displaced slightly from the index mark when the sight is moved to mid-position along the guide 24.
Also, in the embodiment illustrated, the tip of an arrow 16 is utilized as the predetermined point to be brought into registry with the index mark 64. It will be understood, of course, that any other point along the length of the arrow may be selected as the predetermined point for registry with the index mark. For example, a line may be scribed about the circumference of the arrow at any desired position along the length of the latter, to serve as the predetermined point for registry with the index mark, thus to establish the length to which the arrow is to be drawn.
FIGS. 2, 3 and 4 of the drawing illustrate in broken lines the position of an arrow 16, supported on a rest and properly drawn relative to the bow 10 and to the sight 40. It is to be noted that the arrow is positioned in vertical alignment with the sight. However, it is to be understood that the sight may be displaced laterally from this position of alignment, to correct for windage, as previously explained. In any event, the mirror 62 is adjusted laterally, by provision of the slot 76, for substantially vertical alignment with the mirror and index 64.
From the foregoing it will be appreciated that the present invention provides a draw check capable of use with a wide variety of types and sizes of archery bows. The draw check mirror is mounted for movement with the sight so as to maintain minimum spacing between the sight and mirror throughout the range of vertical movement of the sight, whereby to minimize the degree to which the eye of an archer must move alternately for viewing the mirror and the sight. This minimizes sighting time and maximizes sighting accuracy. The mirror is adjusted angularly relative to the sighting axis automatically as the sight is moved vertically through its range, so as to maintain at the eye of an archer registration of the image of a predetermined point on an arrow and an index mark on the mirror, throughout the range of vertical adjustment of the sight.
It will be apparent to those skilled in the art that various changes may be made in the size, shape, number, type and arrangement of parts described hereinbefore. For example, various other structural arrangements may be provided for interengaging the mirror shaft 70 and base 22 for effecting the automatic angular adjustment of the mirror 62 during vertical movement of the sight. Thus, a system of interengaging gears, rack and pinion, pulley and belt, and other mechanisms may be utilized in place of the cam and cam follower assembly illustrated. As another example, the inner margin of the supporting frame 66 for the mirror may be utilized as an index mark, although the straight horizontal index line 64 is preferred. These and other changes may be made, as desired, without departing from the spirit of this invention.
This invention relates to the art of archery, and more particularly to a draw check by which to insure the repeated drawing of an arrow consistently to the same position relative to a bow.
Most archery bows are provided with a sight element which is adjustable vertically through a distance of 6 or more inches, in correspondence with the range capability of the bow, to provide proper trajectory of an arrow to a target.
It is the fundamental principal in archery that the arrow should be drawn back from the bow consistently to the same length, in order to achieve corresponding consistency of arrow speed and trajectory. Various means, referred to in the art as draw checks, have been provided heretofore to provide the archer with a visual check of the length to which the arrow has been drawn. However, all known forms of draw checks provided heretofore are mounted on a bow in a fixed position, while the sight element is adjustable vertically through a substantial range.
One such draw check comprises a wire mounted pivotally on the bow and arranged to engage an arrow a predetermined distance forwardly of the bow. When the arrow has been drawn to the proper distance, the wire falls downwardly from in front of the arrow, to give visual indication to the archer that the arrow has been drawn to the proper distance. A second form of draw check provided heretofore utilizes the metal tip of an arrow to complete an electric circuit of an indicator light mounted on the bow. Thus, when the arrow has been drawn to the proper distance, the metal tip thereof completes the electric circuit of the lamp. A third form of draw check provided heretofore comprises a mirror mounted on the bow at an appropriate angle to reflect to the eye of an archer the tip of a drawn arrow. The mirror is provided with an index mark with which the arrow tip is to be aligned, when the arrow has been drawn to the proper distance.
Accordingly, with the fixed draw checks of the prior art, the eye of the archer must be shifted by as much as 6 or more inches alternately to focus on the draw check and the sight. This not only introduces a disturbing factor to the archer, but it also contributes adversely to slow and inaccurate sighting.
SUMMARY OF THE INVENTION
In its basic concept, the draw check of this invention involves the mounting of a draw check mirror for simultaneous vertical movement with a bow sight and angular adjustment with respect to the axis of the sight, to maintain at the eye of an archer the image of a predetermined point on a drawn arrow in registry with an index mark on the mirror, throughout the range of a vertical adjustment of the sight.
It is by virtue of the foregoing basic concept that the principal objective of this invention is achieved; namely, to overcome the aforementioned disadvantages of prior draw checks.
Another important object of this invention is the provision of a draw check of the class described which is of simplified construction for economical manufacture and which is operable with precision throughout the range of adjustment of the bow sight.
The foregoing and other objects and advantages of this invention will appear from the following detailed description, taken in connection with the accompanying drawing of a preferred embodiment.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a fragmentary view in side elevation of an archer in ready position for shooting an arrow from a bow equipped with a vertically adjustable sight supporting a draw check embodying the features of this invention.
FIG. 2 is a fragmentary view in side elevation of the sight elevation adjustment mechanism and draw check illustrated schematically in FIG. 1.
FIG. 3 is a fragmentary plan view as viewed from the top in FIG. 2.
FIG. 4 is a fragmentary view in front elevation as viewed from the left in FIG. 2.
FIG. 5 is a fragmentary enlarged rear elevation of the draw check as viewed from the right in FIG. 2, portions being broken away to disclose details of internal construction.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1 there is illustrated a conventional form of archery bow 10 provided with a hand grip 12, an arrow rest (not shown) above the hand grip, and a draw string 14 with knocking point (not shown) for receiving an arrow 16.
The sight elevation adjustment mechanism illustrated is described in detail in my co-pending application entitled ELEVATION ADJUSTMENT MECHANISM FOR ARCHERY BOW SIGHTS, filed June 16, 1972 under Ser. No. 263,419. It includes an elongated arm 18 adapted to be mounted on the side of an archery bow. The forward end of the arm is connected to a bracket 20 which, in turn, is connected to the rear side of a vertically elongated base 22. The base includes a correspondingly elongated guide 24 of dove-tail cross section which slidably mounts a carriage 26 by means of a correspondingly shaped dove-tail groove. The carriage mounts a sight-supporting block 28, as by screws 30 and 32, for movement therewith.
The sight-supporting block is provided with a transverse bore which slidably receives a collar 34 for longitudinal movement therein. A tapped central bore in the collar adjustably supports an elongated, threaded sight-mounting rod 36. The rod extends through the block, and one projecting end thereof mounts an adjusting knob 38. The opposite projecting end of the rod mounts an archery bow sight 40 integrated with a bubble level 42 contained in a cylindrical housing 44 secured to and projecting from the rod.
The structural arrangement of the sight-supporting block assembly accommodates lateral adjustment of the sight relative to the block, by appropriate rotation of the adjusting knob. This lateral adjustment is a windage compensation adjustment, as will be understood.
A latch member 46 is mounted pivotally intermediate its ends for movement with the carriage 26. One end portion 48 of the latch member forms a finger button, while the opposite end portion 50 is bent outwardly away from the carriage and is formed with an arcuate notch arranged releasably to engage an elongated mircometer screw 52 mounted for axial rotation on the base 22 by means of a pair of spaced bearing members 54. One end of the screw is provided with a knurled knob 56 to facilitate its rotation. The rotational axis of the screw is disposed parallel to the line of movement of the carriage and sight-supporting block on the guide 24. Thus, rotation of the knob effects movement of the carriage, and hence the sight 40, along the length of the guide.
In the use of the elevation adjustment mechanism it is necessary that it be calibrated for the bow on which it is mounted. Thus, a strip 58 of paper is glued to a recess in the guide 24 and various test shooting are made at various ranges. The desired elevation adjustments for the various ranges then are marked on the paper in registry with an index marker 60 projecting from the carriage.
In accordance with this invention, a draw check mirror 62 is mounted for simultaneous vertical movement with the sight 40 and angular adjustment relative to the sight automatically during said vertical adjustment to maintain at the eye of an archer the image of a predetermined point on a drawn arrow in registry with an index mark 64 (FIG. 5) on the mirror, throughout the range of vertical adjustment of the sight.
In the embodiment illustrated, the draw check mirror is mounted in a retaining frame 66. A boss 68 projects laterally from the frame and secures firmly thereto one end of a laterally extending shaft 70. The shaft extends freely through a bearing 72 formed on a support plate 74. The plate is secured removably to the sight-supporting block 28 by means of the screw 30 which secures the block to the carriage. The screw extends through a laterally elongated slot 76 (FIG. 4) in the plate, the slot accommodating a degree of lateral adjustment of the plate and mirror, for alignment of the mirror with an arrow. In this regard, many bows are provided with a laterally adjustable arrow rest and hence it is desirable that the mirror also be similarly adjustable.
From a consideration of FIGS. 1 and 2 of the drawing, it will be apparent that, since the position of the drawn arrow 16 remains fixed relative to the bow 10, the angular disposition of the mirror 62 relative to the sighting axis 78 of the sight must be changed progressively as the sight is moved vertically along the guide 24, in order for the reflected image of the tip of the arrow be maintained in registry with the index 64 on the mirror, at the eye of the archer. In accordance with this invention, such angular adjustment of the mirror is made simultaneously and automatically as the sight is moved through its range along the guide.
In the embodiment illustrated, a sleeve 80 is mounted on the shaft 70 between the boss 68 and the bearing 72. Secured to the sleeve and projecting therefrom is an elongated cam follower arm 82. The outer end portion 82' of the arm is offset angularly toward the base 22 for sliding engagement with the operating surface 84' of an elongated cam plate 84. This plate is secured to the side of the base by means of attaching screws 86 which extend through openings in the cam plate and into threaded openings in the base. At least one of the screw openings in the cam plate, the lower screw opening 88 in the embodiment illustrated, is elongated arcuately to provide a degree of adjustment of the cam plate. This enables the draw check to be mounted upon a variety of types and sizes of archery bows and adjusted to accommodate the characteristics of the bow.
The sleeve 80 is secured releasably to the pivot shaft 70 of the mirror by such means as a set screw 90. Accordingly, the sleeve and shaft are adjustable rotationally relative to each other and secured in desired position of adjustment by the set screw. This accommodates angular adjustment of the mirror, as may be required for different bows.
Resilient means is provided for maintaining the cam-engaging portion 82' of the cam arm in engagement with the cam surface 84' of the cam plate. In the embodiment illustrated, such means is provided by a coil spring 92 which encircles the portion of the mirror shaft 70 projecting through the bearing 72. One end of the coil spring is secured to the shaft, as by engagement in a hole in the shaft. The opposite end of the spring abuts the support plate 74. The coil spring thus urges the shaft rotationally in the direction to maintain the cam arm in sliding engagement with the cam plate.
The operating surface 84' of the cam plate is contoured, relative to the longitudinal axis of the guide 24, to cause the mirror 62 to pivot progressively as the sight 40 moves vertically along the guide, to adjust the angle of the mirror relative to the sighting axis 78 of the sight, so as to maintain at the eye of an archer the image reflected from the mirror of a predetermined point on a drawn arrow 16 in registry with the index 64. This is best illustrated in FIG. 2 of the drawing by comaring the angular positions of the mirror relative to the sight axis in the full and broken line positions shown. Thus, in the full line position the angle of the mirror is such as to provide an angle a of reflection of the tip of the drawn arrow to the eye, the latter being located on the sighting axis 78 (FIG. 1). When the sight 40 has been lowered on the guide 24 to the broken line position, the point of engagement of the cam arm with the cam surface has caused the mirror to pivot counterclockwise to an angular position relative to the sight axis to provide the angle b of reflection of the arrow tip to the eye of the archer.
Accordingly, with the arrow maintained in properly drawn position and the archer's eye maintained in proper position relative to the bow, the reflected image of the tip of the arrow will be maintained in registry with the index 64 on the mirror, as viewed by the archer, throughout the range of vertical adjustment of the sight along the guide. Moreover, the distance between the sight and index mark on the mirror remains substantially constant throughout said range of adjustment. Since this distance is very short in relation to the distance from the sight to the eye of the archer, the amount of shifting of the eye alternately to view the sight and the index mark, is negligible.
It will be understood, of course, that when the sight is moved downward to the broken line position illustrated in FIG. 2, the entire bow assembly will be swung arcuately upward so that the sight once again is coincident with the line 78 of sight from the target to the eye of the archer.
In the embodiment illustrated, the operating surface 84' of the cam plate is slightly arcuate, having a radius of approximately 20 feet. Although the necessity of this curvature is not completely understood, it has been found that if the operating surface is formed as a straight line, the image of the arrow tip is displaced slightly from the index mark when the sight is moved to mid-position along the guide 24.
Also, in the embodiment illustrated, the tip of an arrow 16 is utilized as the predetermined point to be brought into registry with the index mark 64. It will be understood, of course, that any other point along the length of the arrow may be selected as the predetermined point for registry with the index mark. For example, a line may be scribed about the circumference of the arrow at any desired position along the length of the latter, to serve as the predetermined point for registry with the index mark, thus to establish the length to which the arrow is to be drawn.
FIGS. 2, 3 and 4 of the drawing illustrate in broken lines the position of an arrow 16, supported on a rest and properly drawn relative to the bow 10 and to the sight 40. It is to be noted that the arrow is positioned in vertical alignment with the sight. However, it is to be understood that the sight may be displaced laterally from this position of alignment, to correct for windage, as previously explained. In any event, the mirror 62 is adjusted laterally, by provision of the slot 76, for substantially vertical alignment with the mirror and index 64.
From the foregoing it will be appreciated that the present invention provides a draw check capable of use with a wide variety of types and sizes of archery bows. The draw check mirror is mounted for movement with the sight so as to maintain minimum spacing between the sight and mirror throughout the range of vertical movement of the sight, whereby to minimize the degree to which the eye of an archer must move alternately for viewing the mirror and the sight. This minimizes sighting time and maximizes sighting accuracy. The mirror is adjusted angularly relative to the sighting axis automatically as the sight is moved vertically through its range, so as to maintain at the eye of an archer registration of the image of a predetermined point on an arrow and an index mark on the mirror, throughout the range of vertical adjustment of the sight.
It will be apparent to those skilled in the art that various changes may be made in the size, shape, number, type and arrangement of parts described hereinbefore. For example, various other structural arrangements may be provided for interengaging the mirror shaft 70 and base 22 for effecting the automatic angular adjustment of the mirror 62 during vertical movement of the sight. Thus, a system of interengaging gears, rack and pinion, pulley and belt, and other mechanisms may be utilized in place of the cam and cam follower assembly illustrated. As another example, the inner margin of the supporting frame 66 for the mirror may be utilized as an index mark, although the straight horizontal index line 64 is preferred. These and other changes may be made, as desired, without departing from the spirit of this invention.