US1211399A - Sighting apparatus. - Google Patents

Description

OR 1.211.3Q9 5R W. A. BURNS.

SIGHTING APPARATUS.

APPLICATXON FILED ocT. 30. 1915.

Patented Jan. 9, 1917.

UNITED STATES PA ENT OFFICE.

WILLIAM ALBERT BURNS, OF DRUMMONDHILL, SCOTLAND.

SIGHTING APPARATUS.

Application filed. October 30, 1915.

To all whom it may concern:

Be it known that I, WILLIAM ALBERT BURNS, a subject of the King of Great Britain, residing at Drummondhill, in the county of Inverness, Scotland, have invented certain new and useful Improvements in Sighting Apparatus, of which the following is a specification.

This invention relates to sights embodying devices to enable the line of sight to be corrected to compensate for deviation of the projectile due to movement of the gun platform at the moment of firing. This deviation is often known as the speed error and requires speed allowance or speed correction to compensate for it.

According to the first portion of the present invention, the raising or lowering of one of the sights to correct for gun platform speed is effected automatically, as the gun is laid by mechanism of such a character that the ratio between the respective distances (measured horizontally from the two sights to a vertical plane perpendicular to the line between them, is equal to the ratio of muzzle velocity of the projectile to the gun-platform speed, this vertical plane passing through the pivot of the foresight.

In the accompanying drawings, Figure 1 is an end elevation, and Fig. 2 is a side elevation of a Maxim machine gun provided with one constructional form of device according to the first portion of the invention for mechanically compensating for speed error in the vertical plane only. Fig. 3 is a similar side elevation showing the position of the movable parts of the device when the gun muzzle is depressed 30. Fig. 4 is a side elevation of the muzzle end of a rifle fitted with a modified form of the device.

Figs. 1 and 2 show .a simple link motion by which the foresight of a Maxim gun may be raised or lowered. J represents the back sight of the gun and F the foresight. The foresight F is carried by two short links (or parallel motion arms) L L the lower arm L being actuated by an arm D. This arm D is so connected by a rod R to a point on an extension C formed on the cross-head C of the pivoting rod H, that it is always parallel or at a given small inclination, as shown in Fig. 2, to the vertical axis of the pivot H. Consequently the arms L L are kept horizontal at all inclinations of the gun assuming the gun platform itself to be horizontal. For example, as shown in Fig.

Specification of Letters Patent.

Patented Jan. 9, 1917.

Serial No. 58,911.

3, the line of sight, which was originally the line nn, is raised to the line ee. Now if the distance SP (Fig. 2) is to the forward speed of the gun platform as the distance V E L is to the muzzle velocity of the gun, this arrangement will correctly lower or raise the sight at all inclinations of the gun, to put on the required vertical speed correction. The distance SP may be made variable to enable the same gun to be.

used on platforms of different speeds or at different speeds of one platform. For this purpose the arms L L are formed with a series of holes for the reception of pins carried by the foresight.

While this link motion system provides a relatively simple method of effecting the necessary vertical movement of one of the sights or one end of a sight bar, it is to be understood that the invention is not confined to it. For, assuming conditions to be for the moment reversed and the gun held stationary while the pivot H is swung forward and backward around the trunnion axis, what .actually occurs is that the partially rotary movement of the point of attachment of R and C is translated into vertical movement of the foresight. Obviously any known means by which rotary or partially rotary movement is converted into reciprocating motion may be employed to raise or lower the sight in the aforesaid manner instead of the construction illustrated in the figures, and any such known means for this purpose may be employed.

In the case of rifles, or other small arms or machine guns, unprovided with a regular pivotal mounting, the connecting rod may as shown in Fig. 4) be replaced by a vertical pendulum PL W for the purpose of effecting the necessary raising or lowering of the sight. The pendulum may be inclosed in a suitable casing CS to prevent wind blowing it about, and the casing may be partially filled with viscous liquid or other means may be provided to prevent minor vibrations or movement affecting the hang of the pendulum.

What I claim and desire to secure by Letters Patent of the United States is 1. Sighting apparatus having a foresight and a rear sight, in combination with means for automatically varying the position of one of the sights as the gun is being laid, said means being of such construction that the ratio between the respective distances,

measured horizontally, from the two sights to a vertical plane perpendicular to the line between them is equal to the ratio of muzzle "velooity of the prgjectilemto ithe, gun-platform speed.

Q'J Sighting apparatus having a foresight and a rear sight, the former being pivotally connected to a part moving in elevation with the gun, in combination with means for automatically moving the foresight as the gun is being laid, said means being of such construction that the ratio between the respective distances, measured horizontally from the two sights to a vertical plane perpendicular to the line between them and passing through the point of connection between the foresight and the part moving with the gun, is equal to the ratio of muzzle velocity of the projectile to the gun-platform speed.

3. Sighting apparatus having a foresight in combination with parallel link mechanism carrying the foresight from a part moving with the gun in elevation, and means for automatically actuating said link mechanism to vary the distance of the fore-sight from the gun am's to compensate for the gun-platform speed.

4:. Sighting apparatus having a fore-sight in combination with parallel link mechanism carrying the fore-sight from a part moving with the gun in elevation and mechanism interposed between the gun and its mounting for automatically raising and lowering the fore-sight as the gun is depressed and elevated.

5. Sighting apparatus having a fore-sight in combination with parallel link mechanism carrying the fore-sight from a part moving with the gun in elevation, and means for automatically actuating said link mechanism to vary the distance of the fore-sight from the gun axis to compensate for the gun-platform speed, said fore-sight being adjustable relatively to the pivots of the link mechanism to set the apparatus to agree with different gun-platform speeds.

In witness whereof, I herewith afiix my signature at New London, Conn, this 4th day of November, 1915.

WILLIAM ALBERT BURNS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. 0.

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