US2486400A - Firearm sight - Google Patents

Description

J. C. GARAND Nov. 1 1949.

FIREARM SIGHT Filed June 7, 1946 Jmhn E. EuTurLd A VLMMXM Patented Nov. 1, 1949 UNITED STATES PATENT OFFICE FIREARM SIGHT John C. Garand, Springfield, Mass.

Application June 7, 1946, Serial No. 675,126

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 4 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to an improved rear sight mechanism for firearms.

The components of those rear sights having means of adjustment for elevation and windage are subject to vibration and shock due to the firing of the weapons on which they are mounted. This is especially true in the case of such firearms as are designed for automatic fire. As a result, such rear sights and the components thereof tend to shake loose from the position in which they are intended to be fixedly set even to the extent where disassembly is apt to occur. In such case these components are apt to become lost due to their small size. Moreover, due to the number and size of these components, the problem of supplying rear sight spare parts to the soldier in the field has been found to be exceedingly complex.

Another disadvantage of present art rear sights exists in the resulting inaccuracy of sighting encountered when the components thereof jar loose. For instance, any loosening of the elevating pinion will cause the peep aperture to hop up due to the shock of recoil and thereby change the adjustment in elevation to which the sight has been set. Obviously such change in setting cannot be immediately detected by the user of the firearm.

Accordingly it is an object of this invention to provide means whereby the small components of 'a rear sight may be assembled to form two major assemblies and whereby such assemblies may be secured to a rear sight base so that unloosening of the components from set positions will not inadvertently occur.

It is a further object of this invention to provide a rear sight which will withstand the shocks encountered in continuous or automatic firing of a weapon without jarring loose to destroy the accuracy of the settings for elevation and windage.

It is a particular purpose of this invention to provide an improved adjustable rear sight for a firearm of the type disclosed in U. S. Patent No. 1,892,141.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is a right side elevational View of the sight shown mounted on the receiver of a firearm;

Fig. 2 is a rear end view of the sight;

Fig. 3 is a longitudinal cross-sectional view of the sight taken along line 3-3 of Fig. 1;

Fig. 4 is a right side elevational view of the fixed base of the sight;

Fig. 5 is a rear end elevational view of the windage assembly;

Fig. 6 is a left side elevational view of the fixed base of the sight;

Fig. '7 is a rear end elevational view of the elevation assembly;

Fig. 8 is an exploded perspective view of the locking nut and washer of the windage assembly; and

Fig. 9 is a rear elevational view of the dog of the elevating assembly.

The rear sight of this invention consists essentially of a fixed base 2 which may be formed as the integral part of the receiver I of a gun, a movable sight base 3 adjustable laterally by a windage assembly 4, and a sighting member 5 supported by movable base 3 and arranged to be elevated or depressed by an elevating assembly 6. The details and functions of the fixed and movable bases 2 and 3 and of the sighting member 5 are substantially identical to those described in U. S. Patent No. 1,929,418, the improvements residing in the means for securing the components of the rear sight into two distinct assemblies and in the means for securing such assemblies to the fixed and movable bases 2 and 3.

Fixed base 2 is provided with oppositely disposed supports I and 8 apertured to receive respectively windage assembly 4 and elevating assembly 6. A plurality of notches 9 are included on the exterior side of support I radially disposed about the aperture therein. Similarly located and disposed are a plurality of serrations In on support 8. Notches 9 and serrations I0 provide means of yieldingly securing the sighting member 5 in any desired position laterally and vertically as will be later shown.

The windage assembly 4 comprises a windage knob II, a locking nut I2 cooperating with a lock washer I3, and a split ring retainer I4. Windage knob II consists of a knurled thumbwheel I5 and a body I6 of smaller diameter provided with threads H at the outer end thereof. An axial hole extends through windage knob II and is counterbored at the thumbwheel end as shown at I8 to receive lock nut I2 and lock washer I3. An annular groove I9 is provided within the interior of counterbore I8 and the inner face of thumbwheel I is provided with a radial series of detents 20 for purposes to be explained.

Lock nut I2 is a short hollow cylindrical member threaded in the interior thereof at 2| for a purpose to be shown. Two oppositely disposed slots 24 are provided at one end of lock nut I2 to permit the use of a suitable tool for turning such nut. On the other end of lock nut I2 are provided two integral oppositely disposed lugs 25.

Lock washer I3 is provided with a substanially D-shaped axial hole 26 as shown in Fig. 8 and a pair of oppositely disposed notches 21. Both faces of lock washer I3 may be provided with notches 21 but in such case each pair of notches is spaced substantially 90 degrees apart with respect to one another. Notches 21 are adapted to mate with lugs 25 on lock nut I2.

An annular groove 28 is provided about the periphery of lock nut I2 and split ring retainer I4 is placed within groove 28. When lock nut I2 and washer I3 are inserted within counterbore I8, split ring retainer I4, first compressed slightly to permit such ring to enter counterbore I8, expands outwardly to engage annular groove I9. Thus lock nut I2 and washer I3 are permanently but rotatably retained within windage knob II.

The elevating assembly 6 comprises a shaft member 23, an elevating knob 29, a retaining Washer 30, a washer-like dog 3|, a washer-like spring 32, and a screw 33 on which a split ring retainer 34 is fitted.

Shaft member 23 consists of a serrated head portion 35 and an axial body portion 36 havin a pinion 3I integrally formed thereon. One end of shaft body portion 36 is threaded as shown at 22 and is longitudinally cut away so as to be substantially D-shaped in section as shown at 58. The serrated head portion 35 is provided with a hole which is internally threaded as shown at 41 in Fig. 3 for receiving screw 33 and counterbored at 38 for the clearance of split ring retainer 34.

Elevating knob 29 is provided with a series of indicia 39 for indication of the elevation setting of sight member 5. A serrated thumbwheel 49 and a detent 4| are provided on knob 29. Knob 29 is hollow in shape and the inner wall is provided with an annular groove 42 for the engagement of retaining washer 30. Two oppositely disposed longitudinal axial notches 48 are also formed in the inner wall for a purpose to be shown.

The right side of washer-like dog 3| is provided with a plurality of radially disposed serrations 43 which correspond to similar serrations on the outer surface of head portion 35 of shaft member 23 and engage therewith when proper assembly is made. Dog 3| is provided with a hole 44 which is tapered inwardly and acts as a stop for the head of screw 33. On the outer circumference of dog 3| are provided two 01 positely disposed integrally formed lugs 49 which are adapted to fit in longitudinal notches 48 in knob 29, to prevent rotation of dog 3| when screw 33 is loosened.

In assembling elevating assembly 6, the washerlike spring 32 is first placed over body portion 36 of shaft member 23 adjacent head portion 35 and then both are inserted into the hollow elevating knob 29. An integral inwardly projecting flange 46 at the rear face of knob 29 shown in Fig. 3 decreases the diameter of the hollow portion to less than that of spring 32 and head portion 35 thereby providing a seat for spring 32. Dog 3| is next inserted within knob 29 with lugs 49 engaging notches 48. Screw 33 is then inserted through tapered hole 44 of dog 3| and a split ring retainer 34 is placed around a reduced diameter portion of screw 33 just beyond the head thereof. Thus screw 33 can not be accidentally disassembled from dog 3|. Screw 33 is then threaded into head portion 35 of shaft member 23 and retaining washer 39 is forced into annular groove 42 on the inside of knob 29 to complete the assembly.

For complete assembly of the rear sight, elevating assembly 6 is inserted through the aperture in support 8 of fixed base 2 and windage assembly 4 is inserted through the aperture in support I and over threaded end 22 of shaft member 23. As lock nut I2 is tightened, lugs 25 thereon engage the corresponding notches 21 on lock washer I3 and can only be disengaged thereafter by exerting a counterclockwise turning force on lock nut I2 by means of a suitable tool inserted in slots 24. Upon tightening screw 33, serrations 43 on dog 3| engage the similar serrations on head portion 35 of shaft member 23 thereby enabling elevating assembly 6 to act as a unit with locking nut I2. But since locking nut I2 is rotatable within windage knob II, adjustments for windage and elevation can be made independently without one affecting the other. Pinion 3'! on shaft member 23 meshes with corresponding teeth provided on the underside of sighting member 5 (not shown) to raise or lower such member according to the direction of rotation of knob 29. When windage knob II is rotated, sight base 3 will move transversely with respect to fixed base 2 either to the right or left according to the direction of rotation of knob I I.

Rotating the elevating assembly 6 will not cause loosening of locking nut I2 therefrom since the threaded end 22 of shaft member 23 is substantially D-shaped in section and is inserted through the correspondingly D-shaped hole 26 in washer I3. Upon being tightened, nut I2 is locked to washer I3 and is consequently locked to shaft member 23 and resists loosening due to vibration of the firearm in use.

When the sight is completely assembled to the firearm, detents 20 on windage thumbwheel I5 engage notches 9 on fixed base 2 and are held in such position by the bias of spring 32. However, when a turning force is applied to thumbwheel I5, detents 20 will cam out of notches 9 and rotate past the raised portions therebetween until the turning force is stopped, whereupon alignment again occurs between detents 20 and notches 9, the bias of spring 32 insuring positive setting of thumbwheel I5 against vibration or jars to the firearm. In a similar manner, elevation knob 29' will be positively engaged against support 8 with detent 4| engaging serrations I0. Due to the fact that only one detent 4| is provided on knob 29, positive alignment with serrations I0 is assured regardless of the position of knob 29 when screw 33 is tightened.

Elevating knob 29 may be readily zeroed by loosening dog-securing screw 33 which releases some of the compression on spring 32. As a result, dog serrations 43 will cam past the serrations on head portion 35 of shaft member 23 as elevating knob 29 is rotated, since dog 3| is prevented from turning due to lugs 49 engaging notches 48. Thus detent 4| can be aligned with a zeroing mark 45 on fixed base 2 without disturbing the setting of sighting member 5.

set-rte ROQM Thus there is here provided an improved rear sight for firearm by means of which settings for elevation and windage can be accurately made independently of one another and such settings will not be disturbed by any vibration or shocks. Furthermore, the components of the rear sight are permanently held in two major assemblies which materially simplifies the problem of supply in the field and eliminates the possibility of loss of parts encountered in prior art rear sights of this type.

I claim:

1. In a firearm sight having a fixed base, a movable base adjustable laterally with respect to the fixed base, and an aperture member slidably mounted in the movable base for movement therein along a path having a vertical component, the combination of, an elevating member journaled in the fixed base and having a threaded shank end substantially D-shaped in section, a knurled windage knob journaled in the fixed base opposite said elevating member and threadably engaged by the movable base, said knob having a counterbore therein for rotatably housing a locking nut threaded on said elevating member shank end, said locking nut consisting of a hollow internally threaded body having integral locking lugs on one end and a tool engaging slot on the other end, and a washer on said elevating member shank end, said washer having a substantially D-shaped axial hole and a pair of oppositely disposed notches, all adapted and arranged whereby said locking nut lugs are engaged by said washer notches thereby securely locking said nut on said elevating member shank end against loosening, and whereby rotation of said windage knob for lateral adjustment of the fixed base is independent of rotation of said elevating member for movement of the aperture member.

2. In a firearm sight having a fixed base, a movable base, and an aperture member slidably mounted in the movable base for movement therein along a path having a vertical component, the combination of, a hollow knurled knob having an annular groove therein and an integral inwardly projecting flange, an elevating member having a counterbored threaded axial hole for receiving a screw, said elevating member having a head adapted to be retained in said hollow knob by said inwardly projecting flange, said head portion having radial serrations on the outer surface thereof, a washer-like spring confined in said hollow knob between said flange and said elevating head member, a washer-like dog having radial serrations on the outer edge thereof for engagement with said serrations on said elevating memher head, said dog having a tapered hole therein, a screw having a tapered head insertable within said tapered hole of said dog and threadably engageable in said threaded axial hole of said elevating member, and a retaining washer adapted to be forced into said knob and be retained in said annular groove whereby said spring, said elevating member and said dog are permanently assembled in said knob and whereby when said screw is tightened said dog acts as a driving member for said elevating member.

3. In an elevating knob assembly for a rear sight mounted to a fixed base on a firearm, means for zeroing said sight in elevation comprising, a knurled hollow knob having oppositely disposed axial notches therein and having indicia for indicating adjustments of elevation inscribed about the outer periphery thereof, a detent on said knob aligned with one of said indicia, an elevating member having radial serrations on the outer surface of the head thereof, said head housed Within said hollow knob, a washer-like dog having radial serrations thereon adapted to mate with and engage said elevating member serrations, oppositely-disposed lugs on the outer circumference of said dog, said lugs adapted to engage said notches in said knob whereby rotation thereof effects rotation of said dog, a screw adapted to releasably secure said dog to said elevating member head, and a zeroing mark on the fixed base, all adapted and arranged whereby when said screw is loosened said dog will be free to rotate independently of said elevating member when said knob is rotated for alignment of said zeroing mark with said detent.

4. In combination with claim 2, a, split ring retainer adapted to extend within said elevating member counterbore and surround said screw immediately in front of said tapered head whereby said screw when disengaged from said threaded hole is loosely but permanently restrained from disassembly with said dog.

JOHN C. GARAND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,821,576 Potter et a1. Sept. 1, 1931 1,929,418 Garand Oct. 10, 1933 2,004,951 Jensen June 18, 1935 2,078,858 Kuhn Apr. 27, 1937 2,406,011 Garand Aug. 20, 1946

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