US2354720A - Low altitude bomb sight - Google Patents

Description

. Aug. 1, 1944. w. J. WAGNER 2,3

LOW ALTITUDE BOMB SIGHT I Filed May 18, 1943 s Sheets-Sheet 1 Aug. 1, 1944. w. J. WAGNER LOW ALTITUDE BOMB SIGHT s She ts-Sheet 2 Filed May 1a, 1945 Aug. 1, 1944. w. J. WAGNER 2,354,720

Low ALTITUDE BOMB SIGHT Filed May 18, 1943 5 Sheets-Sheet 3 Av vs 704 a I #4742": a/. we

' TMEA/E/fl Patented Aug. 1, 1944 LOW ALTITUDE BOMB SIGHT Walter J. Wagner, Eglin Field, Fla.

Application May 18,

3 Claims.

1943, Serial No. 487,485

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for Government for govemmental purposes, without the payment to me of any royalty thereon.

This invention relates to a combined gun sight and low altitude bomb sight for aircraft, and more particularly to an attachment for use with a standard fixed gun sight of the collimator type, which is readily adjustable for use as a gun sight, or a low altitude bomb sight.

An object of the invention is the provision of a combined gun and bomb sighting means for aircraft having fixed guns, whichis selectively adjustable to accurately perform either bombing or gun sighting operations.

Another object is the provision of a combined bomb and gun sighting device which is quickly adjustable for accurate bombing at selectable low altitudes, together with self-adjusting means for quickly and accurately readjusting the sighting device for gun sighting.

The more specific objects and advantages of the invention will be in part hereinafter pointed out, and otherwise become apparent from a consideration of the detailed description taken in connection with the accompanying drawings showing operative embodiments of the invention.

Referring to the drawings,

Fig. 1 is a side elevation of my improved convertible sight, parts being broken away and shown in section, and the lower portion of the sight carrying the light source and optical system being shown in section.

:Fig. 2 is a front elevation of the improved sight, in which the lower portion of the casing containing the light source, reticle and optical systems having been broken away.

Fig. 3 is a fragmentary side elevation of the sight as viewed from the side opposite to that disclosed in Fig. 2 of the drawings.

Fig. 4 is a sectional view. takenapproximately on the plane indicated by the line 44 of Fig. 3.

Fig. 5 is a fragmentary vertical longitudinal sectional view of a slightly modified form of combination sight, and

Fig. 6 is a sectional view taken approximately on the plane indicated by the line 6-5 of Fig. 5.

Like reference characters refer to like parts in the several figures of the drawings, in which I indicates the base portion of a well-known gun sight of the optical or collimator type. This sight comprises the usual reticle 2, and source of light 3, which projects the outline of the reticle onto the mirror 4, where it is reflected through the la mounted on the upper end of the stationary supporting base i.

In the conventional sight, the transparent reflector is usually fixed above the main lens 5 at an angle of approximately 45, and the position of the entire sight must be adjusted so that the reflected image of the reticle appears in the reflector as though it were projected through the reflector to a point materially in front of the reflector, where it will center on a point at a predetermined distance in front of the sight Where the fixed guns of the craft would strike a target if positioned at this point. The sight is ordinarily used in sighting fixed guns, and also gun cameras mounted on airplanes, and, when the guns, or the camera, and the sight are properly aligned, it is only necessary to bring the target observable through the transparent reflector into coincidence with the image of th reticle observable on the reflector or window for the proper sighting operation.

I have discovered that by making the frame 8 adjustable on the pivots, as indicated at 9, and providing a dial indicating mechanism, which is generally indicated at l4 on the drawings and operable by the frame -8, incident to adjustment thereof on its pivots 9, my improved sight may beeifectually employed for accurate low altitude 40 bombing, as well as normal gun sighting.

The indicator mechanism I4 is of well-known 7 construction, including a head or casing l5, having a dial I6, which may be suitably calibrated in sight depression angles, in elevation in feet above the ground, or other suitable indicia, and a cooperating pointer or hand H, which is rotated in proportion to the inward movement of the actuating plunger Ill. The dial indicating mecha- -nism I4 is rigidy carried on a supporting stand-,

ard l9, which is in turn secured in a suitable receiving opening in a bracket 20 rigidly carried by the flanged portion of the upper end of the casing l.

In order to quickly adjust the sight back to gun a main lens system 5 which transfers the *other- 6 5 sighting position, the bracket ll carries a stop screw 2| adjustable to limit the return movement of the frame 8 and its transparent reflector to gun sighting position, as shown in full lines in Fig. 1 of the drawings. A compression spring 22 is disposed between the frame 8 and bracket II, to urge tilting movement of the frame to its normal gun sighting position, resting against the stop screw member 2|. In order to accommodate the spring 22, the side of the reflector frame 8 has projecting laterally therefrom an arm 23 recessed to receive one end of the spring, while the other end of the spring is seated in a recess formed in a laterally offset portion 24 projecting from the side of the bracket H.

The tiltable reflector frame 8 has a comparatively long gauge or dial operating arm 25 projecting therefrom, as best observed in Figs. 2 and 4. This arm carries an actuating screw member 26, adjustably received in a threaded opening, having an actuating head disposed in engaging relation with the end of the actuating plunger l8 for the dial indicating mechanism l4. The screw member 26 initially is adjusted so that the indicator mechanism reads zero while the tiltable sighting frame is in gun or camera sighting position, resting against stop member 2|, and a jam nut 21 is provided on the screw member 26, which istightened to secure the screw'member against; accidental rotational displacement.

In order to adjust the tilting frame for low altitude bombing, I provide a thumb screw 28, threaded in the upper end of the bracket II, as seen in the drawings, having its extremity engaging the offset portion 29 of the tilting frame 8.

Rotation of the thumb screw 28 to the right forces the upper end portion of the tiltable reflector frame 8 away from the upper end of the bracket ll, thus tilting the frame 8 to a position somewhat as shown in dotted lines in Fig. 1 of the drawings, while the arm 25 on the lower end of the frame causes a corresponding relative actuation of the indicating mechanism l4. It is only necessary to adjust the thumb screw 28, while watching the pointer l1 until the same registers with the proper indicia on the 'dial, indicating the altitude or angle at which it is intended to bomb. When the frame 8 is tilted to the proper reference angle, as observed on the indicating mechanism l4, the effective sighting position of the reflected reticle image will be correspondingly depressed, as, for instance, to some lower position similar to that shown in dotted. lines on the reflector 1 in Figure 2 of the drawings. A jam nut 29 is preferably provided on the thumb screw 28 to secure the reflector frame 8 in its adjusted bombing position against accidental displacement.

In the operation of my improved sight, assuming that the stop screw 2| has been previously set to position the reflector so that the projected image of the reticle thereon is in proper relation to the line of fire of the guns of the aircraft, and the operator desires to drop bombs at a predetermined elevation on a target, he will rotate the thumbscrew 28, causing the reflector frame 8 to be tilted, thus depressing the apparent image of the reticle as seen on the transparent reflector 1. As the frame is tilted, the headed screw member 26 in the elongated arm 25 projecting 7 'from the frame 8 moves the actuating plunger l8 of the indicating device inwardly, causing the pointer l1 to be moved from its previous zero position. By observing the indicia on the dial I6 of the indicator device l4, and the position of the pointer, the operator may readily and quickly having been previously calibrated,

adjust the transparent reflector for bombing at any specific altitude from the ground, the dial taking into consideration the speed of the aircraft, angle of descent of the bombs, and other necessary calculations. The jam nut 29 may then be tightened, if desired, to secure the sight in bombing position.

When it is necessary to quickly readjust the sight for gun fire, the operator has only to loosen the jam nut 29 and rotate the thumb screw to withdraw it from its engagement with the tiltable frame 8 carrying the reflector I. The pressure of the return spring 22 on the lower portion of the tiltable frame 8 returns the frame to its correct sighting position for the guns of the aircraft as it comes to rest against the stop member 2|, carried in the bracket II on the supportingside frame l3.

Referring now to Figs. 5 and 6, disclosing a slightly modified form of myimproved combination sight, as applied to cowl mounted types of optical or collimator sights, the numeral 30 indicates the cowl of the aircraft, just back of the windshield, while the base portion of the sight containing the light source, reticle, mirror and optical lens system, is indicated at 3|, the apparent image of the reticle being projected upwardly through an opening in the cowl onto the inclined transparent reflector 32, as previously set forth.

In this type of sight, the transparent reflector 32 is rigidly carried in a frame 33 pivotally carried in a second frame 34, supported at four points 35 on the inclined standard 36, which standard is, in turn, rigidly secured to the cowl, as seen in the drawings. The standard 36 carries a fixed bracket 31, in which the mounting stem 38 for an indicating device 39 is secured. This indicating device is similar to the indicatin device 14, and carries an actuating plunger 49, surrounded by a compression coil spring 4| which bears at one end against the head of the plunger 40, and at the other end against the case of the indicating device.

The sighting frame 33 is pivoted at opposite sides, intermediate its ends, as indicated at 42, to the second frame 34. The lower end portion 43 of the sighting fram is provided with an adjustable actuating screw 44 having a head 45 engaging the end of the plunger 40 of the indicating device 39. The opposite end of the sighting frame 33 rests against a pair of stop shoulders 46 formed on the second frame 34, at the upper portion thereof.

The means for moving the sightin reflector 32 from normal gun sighting position to bombing position is similar to that previously described in connection with Figures 1 to 4, and comprises a thumbscrew 41, carried in a bracket 48, which is secured to one of the side members of the inclined frame 36, the thumb screw being rotatable in one direction to engage its end with the face of one of the side members of the reflector frame 33 to tilt the frame. A jam nut 49 is provided on the thumb screw 41 for securing the sight in bombing position.

The operation of this form of the sight is the same as set forth in connection with the first described type. The sight is initially adjusted or sighted in so that when in sighting position for the guns of the .craft the reflector frame 33 will be held against the shoulders 46-46 on the second frame 34 by the extremity of the spring pressed actuating plunger 40 of the indicating device bearing against the headed end of the actuating screw 44, in the lower portion 43 of the reflector frame 33. The spring 4| on the plunger 40 provides the necessary seating pressure for the frame 33 against the shoulders 46-46 of the frame 34, and, of course, the pointer of the indicating device is at this time at the zero indication on the dial.

When the sight is to be set for bombing, the thumb screw 41 is adjusted until the dial pointer is opposite the desired indicia corresponding to altitude at which it is intended to bomb and the jam nut 49 tightened, if desired.

The operator need only to fly at the altitude as determined in accordance with the indicia on the indicating device, or at an altitude predetermined with respect to the bomb falling angle, as observed opposite the end of the pointer, and when the object or target to be bombed comes into alignment with the apparent reticle or sight image, as reflected on the transparent reflector 32, release his bombs, and they will hit the target squarely.

If a camera is used, the camera must be preset, and fixed in predetermined picture-taking position or direction, in accordance with a certain indicia on the indicating device. When the thumb screw 41 is manipulated to tilt the sighting frame 33, and the pointer is opposite this certain indicia, the camera will be centered on the object, as observed in, alignment with the apparent reticle image reflected on the reflector glass 32 of the sight.

Reverse rotation of the thumb screw 41 permits the sighting reflector to be immediately and ac- 1. In a combined and low altitude bomb ing optical sight of collimator type, a support, a light source, a lens system for receiving light rays from said light source and transforming said rays into substantially parallel light rays, a reticle disposed in the path of the light rays between the lens system and light source, a tiltable sighting frame including a transparent sighting reflector and horizontally pivoted on 'said support in the part of said substantially parallel light rays to receive the projected sighting image of the reticle, said sighting reflector being controllably tiltable to reflect the projected sighting image of the reticle at predetermined sighting angles in the line of vision of an operator, positive stop.

means on said support to engage said sighting frame when moved in one direction to position the same in gun sighting position, means for moving said sighting frame in said direction to-- ward and against said stop means, a visual indicator means for indicating predetermined angular sighting positions of said sighting frame for different low altitude'bomb sighting elevations including a shiftable operating connection between said sighting frame and the indicator means, and manually adjustable means on said support engaging said sighting frame for moving the sighting frame about its pivots away from said stop means and to the said predetermined angular bombing sighting positions indicated on said visual indicator means.

2. In a combined gun and low altitude bombing optical sight of the collimator type, a support, a light source, a lens system for receiving light rays from said light source and transforming said rays into substantially parallel light rays, a reticle disposed in the path of the light rays between the lens system and light source, a tiltable sighting frame including a transparent sighting reflector horizontally pivoted on said support and disposed in the path of said substantially parallel light rays to receive the projected sighting image of the reticle and controllably tiltable to reflect the same at predetermined sighting angles in the line of vision of an operator, positive stop means on said support to entween said sighting frame and the indicator means, manually adjustable means on said support for engaging and moving said sighting frame about its pivots away from-said stop means to the said predetermined low altitude bombing positions indicatedon said visual indicator means, and means for locking said sighting frame in any of said last mentioned positions.

3. A combined low altitude bomb and gun sighting attachment for optical sights of the collimator type comprising a casing containing a light source, an opaque reticle adjacent said light source having a transparent sighting image thereon and lens means for receiving the light rays passing through said reticle sighting image and transforming said light rays into substantially parallel light rays, said attachment comprising a flxed support adapted to be positioned above said collimator sight, a transparent sighting reflector horizontally pivoted on said flxed support to receive the substantially parallel light rays defining the reticle sighting image, and tiltable about its pivots to reflect said light rays at a selectable predetermined low altitude and gun sighting angle with respect to said support, and fixed guns thereon, stop means on the support engaging said transparent sighting reflector to prevent tilting movement of the said reflector in one direction past said predetermined gun sighting position, resilient means between said support and'said reflector means for yieldably holding said sighting means against said stop means, separate means for adjustably tilting said reflector in the opposite direction away from said stop means to said predetermined low altitude bomb sighting positions, and a shiftable indicator fixed on said support having actuating means therefor engaging said sighting reflector means and movable thereby to indicate predetermined gun and bomb sighting positions of said sighting reflector upon movement of said sighting reflector to said lastmentioned sighting positions.

. WALTER J. WAGNER.

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