US3433552A

US3433552A - Telescopic bow sighting device

Info

Publication number: US3433552A
Application number: US518319A
Authority: US
Inventors: James R Benford; Herbert D Korones
Original assignee: Bausch and Lomb Inc
Current assignee: Bausch and Lomb Inc
Priority date: 1966-01-03
Filing date: 1966-01-03
Publication date: 1969-03-18
Anticipated expiration: 1986-03-18

Description

March 18, 19 9 J. R. BENFORD ETAL TELESCOPIC BOW SIGHTING DEVICE Filed Jan. 3, 1966 V' -QJQ 2 ATTORNEY United States Patent TELESCOPIC BOW SIGHTING DEVICE James R. Benford, Irondequoit, and Herbert D. Korones,

Brighton, N.Y., assignors to Bausch & Lomb Incorporated, Rochester, N.Y., a corporation of New York Filed Jan. 3, 1966, Ser. No. 518,319

US. Cl. 350-10 Int. Cl. G02b 27 /36 5 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a telescopic sighting device and more particularly it relates to the optical system of a sighting device for use on an archers bow.

Although telescopic sighting devices for guns are well known in the art, special and distinct problems are encountered when attempts are made to use such devices on on archers bow. Because of the exceedingly high trajectory angle which an arrow must trace in its flight compared to guns, telescopic gun sights cannot be used easily in archery installations since to elevate the bow (as is usual in shooting at long range) requires a large angular rotation of the front of the arrow about the anchor point which is usually on the face in close approximation to the eye. Such rotation would result in the sight not pointing at the target, and a counter-rotation of the sight would be necessary to restore the aiming axis. However, such counter-rotation would result in elevation of the eyepoint of the sight so that in order for the archer to see the target, a vertical translation of the sight would be required. Considerations such as these indicate that the mechanical construction and adjustments necessary to use a standard telescopic sight would be very complicated and costly to assure satisfactory performance. In remedying this difficulty, an exceedingly large elevation adjustment must be incorporated in the sighting device and additionally other means must be provided to compensate for the characteristic stance and position of the shooter with reference to said trajectory.

In view of the foregoing statements, it is an object of the present invention to provide a telescopic sighting device for an archers bow, said device being compact and convenient to use while providing a superior aiming capa- :bility, together with a wide range of adjustments in both elevation and windage as well as a long eye-relief.

It is a further object to provide an optical sighting device which is comparatively light in weight and contains few movable parts so that reliability is increased.

Further objects and advantages will be apparent in the combination and arrangement of parts of the invention by reference to the following specification taken together with the accompanying drawing, wherein:

FIG. 1 is a general optical diagram showing one form of the present invention;

FIG. 2 is a plan view of an operating unit shown in FIG. 1; and

FIG. 3 is a partial optical diagram showing another form of said invention.

Optical sighting devices for use on an archers bow such as described herebelow may be constructed in various detailed forms, a preferred form thereof being shown in the drawing. As shown in FIG. 1 of the drawing, the telescopic bow sighting device is generally designated by numeral 10 and it comprises an objective lens 11 which is aligned on an optical axis 12.

According to the present invention, the advantages of a long telescope are obtained in a short length by folding the optical axis 12 to form an offset portion which results in a compact and sturdy design. The offset portion of the optical axis is provided by a system of fiat mirrors, the first mirror 14 being located obliquely on said axis near said objective lens 11. From the first mirror 14, the

image rays

15 and 16 are reflected laterally to a second oblique mirror 17, the optical axis 12 intersection the second mirror at a point 18 thereon.

The U-shaped offset optical axis portion 19 is extended from point 18 toward the eyepiece 13 where a third deviating mirror 20 is located. On the U-shaped offset axis portion 19, the objective lens 12 forms an image plane 21.

Advantageously for the purposes of this invention, a two member type of erecting lens system is provided consisting of a pair of erecting

lenses

22 and 23 which are spaced on opposite sides of the third deviating mirror 20 for a purpose to be explained hereinafter. The image formed by the objective at the image plane 21 is reimaged by said erecting lenses at a second image plane 24 located on rearmost leg of the offset axis portion 19.

Rearwardly of the erector lens system is aligned the aforementioned eyepiece 13 which is focused on the image plane 24, the optical axis thereof being substantially aligned with point 27 on the optical axis of the objective 11 by interposition of the oblique mirror 25. Thereby the sighting device 10 may be used by either right or left handed shooters, the only change being inversion of the device.

For the purpose of providing the elevation adjustments of the bow sighting device 10, the objective lens 11 is pivotally mounted in any preferred manner such as shown .at 26 in FIG. 1 so that it may be moved in an are which is centered at point 27. In order to maintain the position and direction of the optical axis coincident with the point 18 on the mirror 17, the first mirror 14 is pivoted at the point 27 on axis 12. Said mirror 14 is pivoted about the point 27 at half of the speed of the objective 11 by any preferred mechanism such as shown at 29 in FIG. 1. Any suitable mechanism such as there shown may be provided for moving the mirror 14 through an angle 04/2 while the objective is moved through the angle a.

This motion permits the objective lens to be pivoted about point 27 so as to scan the vertical meridian while retaining central imagery of highest quality. Thus, pivoting the objective avoids the introduction of off-axis aberrations which would degrade the image quality, The halfspeed compensatory mirror rotation maintains the optical axis rearward of point 27 unchanged during the elevation adjustment, maintaining the fidelity of image quality.

For the purposes of providing windage adjustments in the bow sighting device,

erector lenses

22 and 23 together with the mirror 20 are mounted as a unit as indicated by the dotted lines 30 which is movably mounted on suitable rails 31 or otherwise to provide lateral motion in a horizontal direction. By varying the off-axis position of the erecting

lenses

22 and 23, the optical axis 12 of the sighting device is deviated horizontally through a given angle 5 from normal in much the same manner as if an optical wedge were used. As mentioned above, the erector lens system may be of any desired form, but preferably the movable unit 30 includes the mirror 20.

A sighting reticle of any preferred configuration is located in the second image plane 24. The above-mentioned J lateral movement of the erector lenses moves the image of the target in the second focal plane 24, thereby introducing the necessary windage.

In order to compensate for the horizontal olfset between the archers eye and the bow, it is possible to laterally dispace the eyepiece of the sight thereby deviating optical axis 12 of the sight in towards the eye of the archer.

A modification of the above-described optical system is shown in FIG. 3 wherein the means for elevating the line of sight of the aiming device involves pivoting of the first mirror per se. In the modified form of the invention, image rays from a distant object are directed parallel to the zero deflection axis 37 and are incident on an inclined flat mirror 32.

For the purpose of adjusting the elevation of the line of sight of the bow sighting device, mirror 32 is pivotally mounted at a transverse pivot point 33 which is coincident with the face of the mirror and the zero deflection axis 37. In optical alignment with and above the mirror 32, an objective lens 34 is mounted in a stationary position so that an image is formed thereby at a subsequent image plane corresponding to image plane 21 of FIG. 1. The optical axis 37 is deflected along an offset portion of axis 35 by a fixed inclined mirror 36 which is optically aligned above the objective lens 34. The remaining parts of the modified bow sight are the same as shown in FIG. 1 and have a similar function. As indicated by the arrow a, the mirror 32 may be adjusted to move through the indicated angle of deflection.

Since the modified optical system Shown in FIG. 3 is much simpler in form than that shown in FIG. 1, the cost thereof is somewhat lower but it necessarily occupies more space.

It is especially noteworthy that the above-described bow sighting device is short and compact so that it is handy to use and requires a minimum of mounting space on the bow. In spite of its small size, the sighting device is capable of optical performance comparable to larger instruments, and without optical changes may be adapted for either right or left hand mountings.

Although only a preferred form of the invention has been shown and described in detail, numerous changes may be made in the form and arrangement of the optical parts without departing from the spirit of the invention as defined in the claims herebelow.

We claim:

1. A telescopic bow sighting device characterized by the combination of an objective lens which is optically aligned on the optical sighting axis of said device,

an eyepiece spaced therefrom and aligned optically therewith,

an erector lens system optically aligned on a vertically offset folded portion of the optical axis between said objective and eyepiece,

a reticle located at a focal plane of the optical system between said erector lens system and the eyepiece,

a first mirror optically aligned with said objective and located adjacent thereto which is tiltable about an axis of tilt which is substantially horizonta and intersects the optical sighting axis, the mirror being tiltable so as to deviate the optical axis in a vertical plane along said oflset portion, whereby elevation adjustments are effected,

a second mirror located on said offset axis portion and aligned to receive rays from said first mirror and direct said rays through said erector lens system,

a third mirror aligned on said oflset axis portion adjacent to said erector lens system, and

a fourth mirror optically aligned between the erector lens system and the eyepiece so as to deflect the rays coming from the third mirror toward said eyepiece.

2. A telescopic bow sighting device characterized by the combination of an objective movably supported for movement in a vertical plane about a horizontal axis perpendicular to the vertical plane with an angular motion designated a,

an eyepiece spaced therefrom and aligned optically therewith,

an erector lens system optically aligned on a vertically oflset folded portion of the optical axis between said objective and said eyepiece,

a reticle located at a focal plane of the optical system between said erector lens system and said eyepiece,

a first mirror aligned with said objective and located adjacent thereto which is also tiltable about the aforesaid horizontal axis so as to deviate the optical axis in a vertical plane along said offset portion, the amplitude of angular tilt being a/ 2 simultaneously and unidirectionally with the movement of said objective whereby elevation adjustments are effected,

a second mirror located on said oflset axis portion and aligned to receive rays from said first mirror and direct said rays through said erector lens system,

a third mirror aligned on said offset axis portion adjacent to said erector lens system, and

3. A telescopic bow sighting device according to claim 1 further characterized by means for holding said erector lens system for movement transversely of the optical system in a horizontal plane whereby said erector system additionally performs the function of deviating the image rays in a horizontal direction to effect windage adjustments in said device.

4. A telescopic bow sighting device as set forth in claim 1 further characterized by said third mirror being located between two component lenses of said erector system and being mounted as a unit therewith for common movement to effect windage adjustments in said device,

5. A telescopic bow sighting device as set forth in claim 4 further characterized by means for adjusting the optical axis of the erecting system including means for moving said unit bodily laterally in said horizontal plane.

References Cited UNITED STATES PATENTS 683,204 9/1901 Grubb 882.4 2,949,816 8/1960 Weaver 35010 X 3,081,670 3/1963 Weisglass 882.4 X 3,202,047 8/1965 Lawler 350-49 3,302,292 2/1967 Akin 3346.4 3,339,450 9/1967 Reed.

FOREIGN PATENTS 769,444 7/ 1954 Great Britain.

DAVID SCHONBERG, Primary Examiner.

T. H. KUSMER, Assistant Examiner.

US. Cl. X.R. 33--46.4