Firearm telescopic range finder

[57] ABSTRACT

A range finder device with a range telescope mounted parallel to and laterally spaced from a conventional gun sight telescope adapted to be mounted on a rifle. The range telescope has an optical and mechanical mechanism for sweeping its line of sight in a generally horizontal plane so that it crosses the line of sight of the gun telescope. A manually rotatable wheel with graduations thereon drives the mechanism for sweeping the line of sight of the range telescope. The graduations are spaced on the wheel in proportion to the included angle formed by the crossing of the lines of sight to provide an indication of the distance between a target at the point of crossing and the rifle on which the range finder device is mounted.

Claims, 5 Drawing Figures

<img file="US3737232A_D0001.tif" />

PATENTED JUN 51973

3.737,232

SHEET 1 OF 2

<img file="US3737232A_D0002.tif" />

INVENTOR /P/9Y/MOA/D £. ///ZAW, J-/?.

BY ''^AAsnAAs /

<img file="US3737232A_D0003.tif" />

<img file="US3737232A_D0004.tif" />

ATTORNEYS

SHEET 2 OF 2

PATENTEDJUN 5 1973

3,737,232

<img file="US3737232A_D0005.tif" />

<img file="US3737232A_D0006.tif" />

400 YDS

OD

MAMSZ M/MSte/? 5CO/te —

CE/V7&amp;?Z/7Vf AMD ZJ//A OX S/OJ/7YDS

<img file="US3737232A_D0007.tif" />

£/M£ OYO/GAT 07? 7?/WGS£/7VD£7?

SCOAS___3—

I / ZOO YDS //Z /tell/

OYDS

INVENTOR 7?AYMO/VD S. M/4-DC//?A/, J/?. BY

ATTORNEYS

3,737,232

FIREARM TELESCOPIC RANGE FINDER

This invention relates to range finders and more particularly to a range finding device for use in conjunction with a telescopic sight for a gun.

Objects of this invention are to provide a range finder particularly suitable for use by sportsmen in conjunction with a gun sight telescope of a rifle which is of comparatively simple design, economical manufacture and assembly, and relatively service and maintenance free.

These and other objects, features and advantages of this invention will be apparent from the following description and accompanying drawings in which:

FIG. 1 is an isometric view of a range finder device constructed in accordance with this invention and mounted on a gun sight telescope of a rifle.

FIG. 2 is an end view through the eyepieces of the range finder with the device zeroed in on a target.

FIG. 3 is a fragmentary plan view of the periscope of the range finder.

FIG. 4 is a fragmentary plan view partially in section of the range finder and gun sight.

FIG. 5 is a schematic diagram of the manner in which the range finder functions.

Referring to the drawings:

FIG. 1 illustrates a range finder device 10 constructed in accordance with this invention mounted by supports or brackets 12 and 14 on a conventional gun sight telescope 16 with a reticle a barrel 18 and eyepiece 20 mounted on a rifle 22. Device 10 has a range finder telescope 24 with a barrel 26, objective lens 28, eyepiece 30 and adjusting screws 33 and 35 for optically shifting the line of sight of cross hairs 32 and 34 of the reticle thereof. Barrel 26 of range telescope 24 is received in yokes 36 at one end of brackets 12 and 14 and retained in the yokes by clamp members 38 secured to the brackets by screws 40 (FIG. 4). The other end of brackets 12 and 14 have yokes 42 which engage barrel 18 of telescopic sight 16 and are fixed thereto by clamping members 44 secured to the brackets by cap screws 40. Range telescope 24 is mounted by brackets 12 and 14 with the longitudinal axis of barrel 26 laterally spaced from and parallel to the axis of gun sight telescope 16. Cross hairs 32 and 34 of range telescope 24 are fixed to one end of a tube 46 slidably received in firm frictional engagement with the inner wall of barrel 26 and having a lens 48 mounted therein adjacent its other end.

As shown in FIGS. 1 and 3, a person using the range finder can simultaneously look through both gun and range telescopes 16 and 24 due to a periscope 50 with a viewing window or eyehole 52. The lateral spacing between eyehole 52 of periscope 50 and eyepiece 20 of gun telescope 16 can be adjusted to accommodate a wide range of eyespacings for various viewers. A hollow tubular L-shaped body 54 with a window 56 of a transparent material such as glass is slidably received in an L-shaped tubular body 58 and is locked in various positions of sliding adjustment by a threaded locking screw 60 received in a slot 62 in body 54. Body 54 is retained in body 58 by a screw 64 extending through bracket 12 and riding in an elongated pocket 66 in body 54. Tubular body 58 has a reduced shank 67 adjacent one end which is generally coaxial with eyepiece 30 of range telescope 24 and is received in yoke 36 and clamping member 38 of bracket 12 to fixedly mount periscope 50 on the end of telescope 24. Flat silvered mirrors 68 and 70 are mounted in bodies 54 and 58 respectively generally parallel to each other and at 45° to the longitudinal axis of periscope 50 so that the image formed by eyepiece 30 of range telescope 24 can be viewed through eyehole 52.

As shown in FIG. 4, the line of sight or elevation and windage of horizontal hairline 32 and vertical hairline 34 respectively of range telescope 24 is optically adjusted by arcuate movement of a pair of lenses 72 and 74 in barrel 26. Lenses 72 and 74 are fixedly mounted in a sleeve 76 with a flange 78 adjacent one end slidably received in barrel 26 for generally pivotal movement about flange 78. Adjusting screws 33 and 35 optically shift the elevation and windage of the horizontal and vertical cross hairs by pivotally moving sleeve 76 in vertical and horizontal planes respectively. Adjusting screws 33 and 35 are threadingly received in a bracket 80 secured to barrel 26 by screws 82 threadingly engaging a ring 84 slidably received in barrel 26. Adjusting screws 33 and 35 are positioned so that they bear on sleeve 76 adjacent its free end at a right angle to each other and sleeve 76 is urged into firm engagement with the adjusting screws by a leaf spring 86 with its opposed ends engaging in slots in sleeve 76 and ring 84 to retain sleeve 76 is spaced relation to ring 84. A range telescope 24 including adjusting screws 33 and 35 for optically shifting the line of sight or elevation and windage of cross hairs 32 and 34 is commercially from the Savage Arms Division of Emhart Corp., Westfield, Mass., U.S.A., Zip Code 01085, and can be ordered as Savage — SUWA Model 0420A.

As shown in FIGS. 1 and 4, a knurled wheel 88 connected to windage adjusting screw 35 can be manually rotated to sweep the line of sight of range telescope 24 in a generally horizontal plane to provide in cooperation with gun sight telescope 16 an indication of the range of distance from a target to the rifle or gun 22 on which range finder device 10 is mounted. Wheel 88 has a plurality of graduation 90 and yardage indicia 92 and is fixed to a drive shaft 94 by a set screw 96. A pointer 93 is fixed to bracket 14 adjacent wheel 88 to cooperate with graduations 90 and indicia 92. Shaft 94 is mounted for rotation in bronze bushings 98 pressed into axially aligned holes 100 extending through arms 102 of bracket 14. Shaft 94 has a tang 104 adjacent one end which is received in a slot in windage screw 35 and is urged into firm engagement with screw 35 by a compression spring 106 bearing on the other end of shaft 94. Spring 106 is retained in the bushing 98 adjacent the other end of shaft 94 by a set screw 108.

The way in which range finder device 10 functions to indicate the distance to a target is schematically illustrated in FIG. 5. In FIG. 5 both the center line and line of sight of gun sight telescope 16 are represented by line 112 with rifle 22 and gun telescope 16 located at point 114 on the zero yard line. With gun sight telescope 16 in this position range telescope 24 will be located at point 116 on the zero yard line with its center line laterally spaced from and generally parallel to center line 112 as indicated by center line 118. Graduated wheel 88 is rotated so that screw 35 is retracted which allows spring 86 to sweep the free end of sleeve 76 in a horizontal plane to the right (as viewed in FIG. 4). This sweeps the line of sight of range telescope 24 as indicated by broken line 120 in FIG. 5 in a generally horizontal plane to the right across the line of sight 112

3,737,232 of gun telescope 16. The distance between the location 114 of gun telescope 16 and the point at which lines 120 and 112 cross will be proportional to the angular displacement of line of sight 120 of range finder telescope 24 with respect to line of sight 112 of telescope 16 as indicated by θι through 0_t. By knowing the lateral distance or spacing between the center lines 112 and 118 of gun sight telescope 16 and range finder telescope 24 and the angle between the lines of sight 112 and 120, the distance from point 114 or the range finder 10 to the point of crossing of lines 112 and 120 can be calculated by the methods of plane geometry. If line of sight 120 is swept or shifted until the point at which it crosses line of sight 112 is coincident with a target then the distance between the target and device 10 is equal to the distance between point 114 and the point of crossing of lines of sight 112 and 120. The angular position of line of sight 120 is dependent upon the pivotal position in a horizontal plane of the longitudinal axis of sleeve 76 and lenses 72 and 74 with respect to the center line of telescope 24 and is thus proportional to the displacement of windage adjusting screw 35. Hence, the displacement per revolution or pitch of screw 35 is proportional to the angular displacement of line of sight 120 and the distance between range device 10 and the target or point of crossing of lines of sight 112 and 120 of gun and range telescopes 16 and 24. Thus the graduations 90 and indicia 92 are spaced about the periphery of wheel 88 in proportion to the displacement of screw 35 by rotation of the wheel to provide an indication of the distance between a target and range finder device 10.

In operating range finder device 10, gun sight telescope 16 of rifle 22 is sighted on or aimed at the bull’seye of a target 122 as shown in eyepiece 20 of FIG. 2 and then knurled wheel 88 (FIGS. 1 and 4) is rotated to turn adjusting screw 35 and optically shift the image of vertical hair line 34 of range telescope 24 from the phantom to the solid line position shown in eyehole 52 of FIG. 2 so that the lines of sight of both telescopes 24 and 16 are simultaneously sighted on or aimed at the bull’s-eye of target 122. The graduation 90 which is most nearly aligned with pointer 93 and indicia 92 on wheel 88 are then viewed to determine how far away target 122 is from the range finder device 10 on rifle 22. For example, if wheel 88 is manipulated so that both range and gun telescopes 24 and 16 are sighted on the bull’s-eye of target 122 when their lines of sight 120 and 112 cross at point 124 of FIG. 5, a graduation 90 on wheel 88 will be aligned with pointer 93 and the graduation’s associated indicia 92 will indicate that target 122 is 300 yards away from rifle 22 and range finder 10 mounted thereon.