US 3492733 A
Description (OCR text may contain errors)
1970 J. M. LEATHERWOOD VARIABLE POWER SIGHTING SCOPE Filed April 23, 1968 mluJ 24 500 OM RWN 0N ud hul WIN Nahum- 00 JAMES M. LET'HEHWQQZD INVENTOR.
TTORNE'Y United States Patent 3,492,733 VARIABLE POWER SIGHTING SCOPE James M. Leatherwood, Rte. 1, Box 120, Stephenville, Tex. 76401 Filed Apr. 23, 1968, Ser. No. 723,523 Int. Cl. F41g 1/38 US. CI. 33-50 1 Claim ABSTRACT OF THE DISCLOSURE A variable power sight pivotally mounted for movement in a vertical plane on a gun barrel and including a trajectory adjustment. The variable power sight referred to is conventional and includes a front focus, a rear focus and an external ring for varying the magnifying power of the sight. The trajectory adjustment of the present invention is generally comprised of a fixed target framing reference of a preselected height in the rear focus and a cam rotatable with the external ring, the rise of the cam making contact with a stationary portion of the gun.
This invention relates to telescopic sights for guns in which the adjustment of the telescope to the range automatically raises or lowers the trajectory of the bullet according to the distance of the target, and which is an improvement on my Patent No. 3,340,614 in which the desired result is achieved by adjusting a pair of cross hairs to include an object of known height, during which process a cam changes the alignment of the scope with the gun barrel, raising or lowering the same so that the allowance for distance is automatically made when the scope is sighted directly on the target.
There is now in common use a telescopic sight including a variable power or zoom element whereby the apparent size of the target image in the scope can be changed by turning an external ring which is connected by an internal linkage to the lenses making up the zoom system. By comparing an object of known height to the space between two permanent cross hairs on the upper portion of the reticle an estimate of the range can be made, but an allowance for the trajectory of the bullet still has to be made according to this estimate and there is possibility of considerable error.
One object of this invention is to provide an automatic coupling between the external ring operating the zoom system in the telescope and the body of the gun so that the line of sight and the barrel of the gun are exactly or nearly exactly related to provide the proper trajectory when the distance of the target has been determined.
Another object of the invention is to provide an adjustable connection between the telescope and the gun which is rugged, reliable and trouble free.
Another object of the invention is to provide means whereby the sight adjusting element can be easily altered to match the type of ammunition being used.
A still further object of the invention is to provide a sight adjusting arrangement which can be simply and economically adapted to zoom type telescopes presently 1n use.
These and other objects will become apparent from the following description and the accompanying drawing, in which:
FIGURE 1 is a side elevational view of a variable power or zoom type telescope and its attachment to a gun according to this invention.
FIGURE 2 is a cross sectional view taken along line 22 in FIGURE 1.
FIGURE 3 is a diagram of the optical system of the scope used in the invention.
3,492,733 Patented Feb. 3, 1970 FIGURE 4 is a diagram of a target seen through the scope when the latter is not adjusted to the range.
FIGURE 5 is a diagram of the target seen through the scope when the latter is adjusted to the range, and
FIGURE 6 is a diagram of the target seen through the scope after the range has been determined and the gun has been aimed ready for firing.
As illustrated in FIGURE 1, the type of telescopic sight herein considered, and designated generally by the number 10, includes an eyepiece 11, an objective 12 and a barrel 13 containing the erecting and magnifying lenses assembled in a zoom system, which are not illustrated except diagrammatically in FIGURE 3.
An adjusting ring 14, operates (by means of internal linkage not shown) the zoom element of the scope so that the image of the target can be made to look larger or smaller in proportion to the field, as well known in the art. A handle 15 on the adjusting ring 14 facilitates its adjustment. The scope 10 is mounted securely on the gun by means of a bracket 17 and screws '18. A rear clamp 19 is integral with the bracket 17 and a forward clamp 20 is connected to the bracket by means of a substantial and relatively tight pivot 21. A stationary stud 22 extends upwardly from the gun 16 toward the adjusting ring 14- and is surrounded by a ring 23 integral with the rearward end of the bracket 17. The bracket 17 is thinned just behind its attachment to the gun 16 to provide a spring portion 24 which is stressed to hold the rearward end of the sc0pe 10 tightly against the stud 22.
A cam 25, sized at the inside to fit the adjusting ring 14, is held rigidly to the latter by means of a machine screw 26. The outer surface 27 of the cam 25 is shaped to align the scope -10 with the gun 16 in a manner hereinafter described.
Referring now to FIGURE 3, a standard sighting telescope has within it two points of focus at which the reticle holding the cross hairs can be located. In a nonzoom type scope the reticle is located at the front focus and thus the cross hairs remain clear to the observer even though the field focus is changed by moving the ocular lens. In the zoom type telescope the field is in permanent focus and because of the optical characteristics of the scope it is necessary to place the reticle at the point of rear focus. In the scope used with this invention the reticle is provided with two upper horizontal cross hairs 28 and 29 spaced apart a mathematically determined distance, and with the usual aiming cross hairs 30 and 31 to indicate the exact center of the field. This pattern of cross hairs remains the same throughout the operation of the scope.
The upper cross hairs 28 and 29 are spaced to bracket a target 32 of a known dimension, for example, 18 inches high, at a known distance, such as 200 yards. If the target appears in the scope as shown in FIGURE 4, the scope is set for too great a distance and the adjusting ring 14 is in the position indicated by the dotted handle outline 15a in FIGURE 2. This would raise the rear end of the scope 10 in relation to the gun 16 and cause the pro jectile to overshoot the target. If the adjusting ring 14 is turned to where the handle is in the position 15b in FIG- URE 2, the pattern will appear as shown in FIGURE 5. The target fits between the cross hairs 28 and 29' and the scope is adjusted to the targets true distance. The cam 25 is turned to where its thin portion rests on the stud 22, lowering the rear end of the scope to where the gun will be aimed on target when it is sighted as in FIGURE 6. When the adjusting ring 14- and the cam 25 are in the position shown by solid lines in FIGURE 2 the target will appear approximately as shown by the dotted outline 32a in FIGURE 5.
As an example of how to use the scope in hunting deer, for instance, if the head and chest of the deer are sighted 0n the cross hairs 28 and 29 and the adjusting ring 14 turned until that part of the deer, which measures approximately 18 inches, falls exactly between the cross hairs, the gun can then be aimed directly on the target and the trajectory will have been automatically adjusted to the distance.
If the hunter chooses to switch to a difierent type of ammunition for some reason, a new cam 25 shaped to match the velocity and weight of the new projectile, can be placed on the adjusting ring -14 in a few minutes, and no other adjustment is necessary and no mental calculations are required to compensate for the new type of ammunition.
What is claimed is:
1. In a variable power type telescopic gun sight longitudinally and pivotally mounted on a gun barrel and having an external zoom adjusting ring rotatable about the References Cited UNITED STATES PATENTS 3,340,614 9/1967 Leatherwood 3350 SAMUEL S. MATTHEWS, Primary Examiner