US1440291A - Sighting device - Google Patents

Description

33*260 OR 194409291 SR Dec. 26, 1922. 1,440,291. J.- w. HARKOM.

SEGHTING DEVICE.

FILED MAR, 3, I920.

36 W V25 1 E'B G35 when/0r Ja/m 14K liar/ram iar JOHN W. HARKOM, 0F MELBOURNE, QUEBEC, CANADA.

SIGHTING DEVICE.

Application filed March 8, 1920. Serial No. 364,136.

To all whom it may concern:

Be it known that 1, JOHN WV. HARKoM, a subject of the King of Great Britain, and resident of the village of Melbourne, in the Province of Quebec and Dominion of Canada, have invented certain new and useful Improvements in Sighting Devices, of which the following is a full clear, and exact description.

This invention relates to improvements in sighting devices for small arms and ordnance, and the object of the invention is to provide small, compact and easily adjusted sights which are not liable to get out of order and by means of which small adjustments may be accurately made.

One object is to provide a front sight cooperating with a rear sight to give accurately measured compensation for windage without adjustment of the parts.

A further object is to provide a sight in which elevation may be adjusted by minutes without the use of a micrometer screw.

Another object is to provide a sight in which the same aperture is used as a battle or point blank range sight and as a long distance sight.

Still another object is to provide a rear sight specially adapted for use with a telescope or periscope.

Various other objects and advantages will appear from the following description.

The invention consists briefly in providing a sighting aperture whichis raised and lowered by means similar to a parallel rule, but differing in that the axis of the aperture is increasingly inclined as it is raised whereby it remains erected at a single point which is the tip of the foresight. The aperture is raised by means of a lever operating over a venier scale, which is arranged preferably to give readings in minutes as well as for fixed ranges. The foresight is preferably provided with two very low strong blades or points between which the normal sight is taken. These blades and the distance between them bear an exact relation to their distance from the rear sight, whereby deflection or windage may be given by aiming over different parts of the foresight.

In the drawings which illustrate the invention;

Fig. 1 is an elevation of the right hand side of a rear sight, according to this invention, showing the sight in its extreme positions.

Fig. 2' is an elevation of the left hand side of the sight.

Fig. 3 is a plan view.

Fig. 4 is a rear elevation, the sight being about half raised.

Fig. 5 is an enlarged side elevation partly in section.

Fig. 6 is a front or rear elevation of a foresight adapted for use with the rear sight shown in Figure 1.

Fig. 7 is a side elevation of the foresight.

Fig. 8 is a diagram illustrating the operation of the invention.

The device comprises as its main elements a rear sight bed or body 11, a block 12 which corresponds with the slide of an ordinary leaf sight, an adjusting or elevating lever 13, and a pair of links 14 and 15 by means of which the block is mounted in the bed and which corresponds with the leaf of an ordinary rear sight. The present sight differs in principle from the ordinary leaf sight in that the vertical adjustment of the block is effected by the angular adjustment of the levers 1% and 15.

The body 11 is of any suitable shape and size and adapted for attachment to the stock or other part of a rifle and includes a pair of parallel upstanding flanges 16, between which the block 12 is slidable. Pins 17 are secured between these flanges and each support one end of the levers 14 and 15 which may have double or single arms. Each flange or web 16 of the bed is provided with a quadrant-shaped slot 18.

The block 12'is longitudinally curved at its upper edge and pivotally connected toward the extremities of its lower edge to the rockers 14 and 15 by pivot-s 19. The lower edge of the block is designed to normally rest on the hubs of the rockers and thus to limit the lowering movement of the block and at the same time to support the same upon the bed through the medium of the pins 17, so that the rockers are relieved of all load. The block is provided with sight apertures 20 at front and rear ends, the common axis of which aligns with the tip of the foresight and is substantially parallel with the axis of the rifle barrel when the sight is in its lowered position. The upper edge of the block may be provided at its front end with a lip 21 and at its rear end with an upward projection 22 rounded on the top, as clearly shown in Figure 4. The upper edge of the block is provided with a Vernier scale 23 reading in minutes, an elevation scale 24 reading in hundreds of yards or other suitable sub-divisions, and with a series of shallow depressions 25 for locating fixed ranges.

The adjusting lever 13 is U-shaped as viewed from the front or rear and spans the body or bed flanges 16, to which it is pivoted by a pin 26 screwed into the lever and journalled in the bed. A pin 27 disposed eccentrically to the pin 26, passes through the lever through the slots 18 of the bed flanges and through the block. One end of this pin is provided with a head 28 fixed to the lever by a screw 29, while the other end carries a small screwed-on lever 30, which serves to clamp the sight in any position in which it may be adjusted. The head 28 holds the pin 27 against revolution and the lever 30 is held against turning through one or more complete revolutions by the head of the pin 26, so that the lever 30 is guarded against loss. This pin limits the upward movement of the block by striking the ends of the slots 18. The axis of the pin 26 is arranged in the same plane as the axes of the pins 17 and, when the sight is in its lowered position, the axis of the pin 27 is preferably in the same plane as the axes of the pivots 19. The back rocker 14 is slightly longer than the front rocker 15 and the distance between the axes of the pins 26 and 27 is proportional to the rocker lengths according to the position of the pin 26 between the pins 17. This is obviously necessary in order that the relation between the pin 27 and the block pivots 19 may remain the same in all positions of the block. Obviously, the bed slots 18 are described from centres in the axial line of the pin 26. The bridge 31 of the lever 13, that is the lever portion overlying the top edge of the block 12, rests in the normal position of the sight on the lip 21. The rear edge of this bridge is sharpened to an edge and forms an indicator 32 travelling over the Vernier and yard scales on the block. A finger piece 33 is secured to the bridge and holds in place a spring-pressed detent 32 adapted to enter the depressions 25 of the block 12.

The foresight designed for use with the rear sight just described comprises a block 35 having a pair of low wide blades 36 at the upper edge thereof. These blades are of calculated width and distance apart, so that by holding the target over any given part of the foresight a known amount of defiection may be obtained. The proportions of the space between the blades 36 are preferably-depth equals half the width-and the tops of the blades should correspond in level with the top of the blade of an ordinary sight.

As previously stated, the back rocker 14: is longer than the front rocker 15. The result is that as the sight block is raised, the back end thereof will rise more than the front end. The lengths of these rockers are such as to produce a regularly increasing inclination of the block as it rises, for the purpose of keeping the axis of the sight apertures in alignment with the tip of the foresight. This action is illustrated in the diagram, Figure 8. It will be understood that as the diagram is greatly contracted in length and exaggerated in height, it is accurate only at the extreme positions indicated. This inclination of the aperture axis is of no importance when the aperture is formed in a thin plate but, when the apertures are spaced apart as in the present instance, such inclination becomes necessary for two reasons. In the first place without inclination, the line of sight through the apertures would soon miss the foresight altogether and the device would be useless for its purpose. In the second place, the spaced apertures act as a telescope and looking through the same has a peculiar efi'ect on the eye which urges one to centre the object looked at in the apertures. This inclination of the axis of the sight aperture enables a telescope or periscope to be attached to the block and the aiming to be effected without any adjustment of the telescope or periscope apart from that given by the sight. The scales shown in Figure 3 are not necessarily in proportion with one another and are merely for the purposes of illustration.

The operation of the device is extremely simple. The clamping lever 30 is swung rearwardly and the operating lever 13 raised as desired, preferably by placing the fore finger in front of the part 33. This leaves the thumb free to throw the clamping lever 30 forward to lock the sight in set position. while the fore finger holds the sight against movement during the clamping. The shooter looks through the sighting aperture 20 and, as these are always alinged with the foresight, there is no ditiiculty in bringing the foresight into the field of vision. In effect, the shooter really looks through the rear sight at the target and instinctively centres the target in the circular field of vision, so that at the same time the foresight is automatically brought into line. This lining up of the sights and target renders the target normally visible between the blades of the foresight. It will be found much easier to hold the target between these blades than it is to hold the target centered above and ust clear of the tip of a single sharpedged sight blade. If it is found that the elevation is slightly too great or too little,

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a knowledge of the size of the target enables the shooter to determine as the shots are reported how many inches high or low the bullets are striking and to readily calculate the number of minutes elevation to add or subtract, in order to have the shots strike the bulls eye. This calculation is very easy when it is remembered that an angle of one minute subtends at a radius of one hundred yards an arc of one inch. Thus, if when shooting at six hundred yards, a magpie at 6 oclock is reported, the shooter knows that the bullet must be raised twelve inches and that therefore two minutes additional elevation is required. This additional elevation is put on by means of the Vernier scale. Each of the cross lines of the scale indicates a difference of five minutes and the longitudinal intersecting lines divide the cross lines into five parts, so that each intersection represents one minute. The lever 13 is unclamped and the sight raised until the knife-edged indicator 32 reaches the proper intersection of the Vernier.

While the block 12 has been described as supported by the links or rockers 1a and 15 it will be observed that it has a third support namely, the lever 13. As the distance between the pivot pins 26 and 27 of this lever is proportionate to the length of either rocker and the distance of the pin 26 from either of the rocker pins 17, it will be obvious that if either of the rockers is removed the block when raised or lowered will be inclined as already described.

The sizes of the sight apertures should be properly proportioned to the distance be tween them and the normal distance from the shooters eye, in order to secure field of vision for quick shooting, such as is necessary in a sporting rifle or in a military rifle. For purely range purposes, the front aperture may be greatly restricted, thus giving a still sharper definition of the foresight and target but reducing the field of vision. The area of the field of view is governed by the angle which the diameter of the front end of the opening makes with the eye at the rear of the sight. The interior or cavity of the sight block between the apertures is thus obscured and the definition further improved.

When it is desired to give windage, the muzzle of the rifle is moved slightly to one side, so that the target is partly obscured by the blades 36 or appears outside the blades. As these blades and the space between them have a definite relation to the distance between sights, it follows that knowing the range and wind velocity, the shooter may calculate the exact relation of the target and the foresight blades necessary to give the desired correction. Having once obtained the proper correction, it

is a very easy matter to re-align the sights and target in the same manner for further shots, so that great accuracy may be obtained. Obviously, the accuracy will be greater than if the shooter holds the fore- 7 sight to one side of the target and then attempts to hold the same distance off for successive shots.

' It will be observed that to obtain windage, the rear sight is not affected in any 7 way. This is a valuable feature for a sporting or military rifle as there is no possibility of the sight being used with adjustment for windage on it where none is re quired. F or either sporting or military purposes, the sight has the further advantage that the same aperture is used at all times, so that there is no possibility of the shooter becoming confused and endeavoring to find the sight aperture which is not 8 in use. A change from zero to maximum elevation is obtained by the movement of a lever through approximately Obviously this may be effected much more rapidly than where elevating screws are used. hen shooting in very poor light, the proper setting of the sights may be obtained by counting the clicks as the detent slips from one depression 25 to the next. Even if these cannot be heard, they can be felt 9 and counted. The sight is very simple and rugged in construction in addition to being small. If the sight should receive a blow or the rifle be allowed to fall while the sight is elevated, the probabilities are that the block will simply be driven down on to its bed without any damage to the parts, as the clamping levers hold the parts merely by slight friction. The foresight is larger and therefore more rugged than sights ordinarily used and less likely to be damaged.

While the sight has been illustrated and described as pertaining to rifles, it will be understood that it may be employed on a larger scale for machine guns or ordnance. 1 It will also be understood that the same principle may be employed to impart lateral movement as well as vertical movement, especially in connection with ordnance where there is not the same necessity for compact- 1 ness and small space as with small arms. It will be observed that the lever 13 is pivoted to the bed at a different point from either of the rockers. Obviously, the same result might be produced as regards block move- 1 ment by extending either of the pivots 17 into operative connection with the lever and utilizing an extension of the corresponding pivot 19 to connect the lever and block.

Having thus described my invention, what 1 I claim is 1. The combination with a foresight, of an apertured rear sight block, an elevating means therefor adapted to incline the block proportionately to the elevation, whereby the 1 axis of the aperture remains in alignment with the foresight, said elevating means including a lever operatively connected to the block, and a setting scale on the block, according to which the movement of the lever is regulated.

2. The combination with a foresight, of a rear sight bed, a movable apertured block,

connected at one end to the bed and at an intermediate point to the block.

3. In a device of the class described, a bed, an apertured block, a pair of rockers pivotally mounted in the bed and pivotally connected to the block, one of said rockers being longer than the other, and means for raising and lowering the block.

4. A device according to claim 6, in which the upper edge of the block is quadrantshaped and provided with elevation and range scales, in combination with an indicator carried by the lever and moving over said scales.

5. A device according to claim 6, in which the elevating means comprises a lever pivoted to the bed, a pin connecting the lever and block, and means on said pin for clamping the lever, block and bed together.

6. In a rear sight, the combination with a graduated sight block of members to movably support the block including, a lever adjustable to the block graduations to adjust the block to different elevations.

7. In a rear sight a block curvedin its upper surface having a degree scale formed longitudinally on said curved surface, and having a minute scale disposed transversely of said degree scale, means for moving the block to different elevations, and an inclicator carried by said means moving over both of said scales.

8. In a rear sight, an apertured movable block, having a setting scale thereon of greater length than the travel of the block whereby very small block movements may be accurately gauged, means for raising and lowering the block, and an indicator carried by said means travelling over the scale.

9. In a rear sight, a movable apertured sighting block, formed with a, setting scale, a plurality of depressions in predetermined relation to the scale, a setting lever for the block, and a resilient locating device carried by the lever engageable in and disengageable from the recesses of the block.

10. In a rear sight, a bed comprising a pair of parallel flanges provided with curved slots, a sight block normally housed between said flanges, means swingingly connecting the block with the bed, means for raising and lowering the block and means connected to the block passing through said slots and adapted to clamp the block to the flanges in any position to which the block is adjusted.

11. In a rear sight, a movable sighting member having a setting scale formed thereon, a pair of supports for said member relatively formed and mounted to incline the sighting member proportionately to its movement, one of said supports being formed to traverse the setting scale of the sighting member to gauge movement thereof.

12. In a rear sight, a movable sighting member having a setting scale formed thereon of greater length than the path of movement of the member, a pair of supports for said sighting member relatively formed and mounted to confine the member movement to an arcuate path, and an elevating handle for the sighting means secured to one of said supports and traversing the scale of the sighting member, said handle having a greater travel than the sighting member whereby minute adjustments of the sighting member may be readily effected.

In witness whereof, I have hereunto set my hand.

JOHN IV. HARKOM.

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