US561383A - fiske - Google Patents

Description

(No Model.) 2 Sheets-Sheet 2. B. A. FISKE.

-TELESCOPIG SIGHT. A No. 561,383. VPartentcedJune 2,1896.

.mwnmwm u i lwww UNITED STATES BRADLEY A. FISHE, OF THE PATENT UFEI'CE.

UNITED S"TES NAV-Y. I

TELESCOPC SIGHT.

SPECIFICATION forming' pari; of Letters :Patent NO. 561,383, 'dated June 2, 1896. Application'led May 20. 1893. Serial No. 474,872. (No model.)

To all whom it mag/.concerm 13e it known that I,- BRADLEY A. FISKE, of-

the United States Navy, have invented a new and useful Improvement in Telescopic Sights, of which the following is a specification.

My invention relates -to an apparatus for sighting guns.

My invention consists in the combination of a telescope orsi ght-bar and a gun,each movable about a transverse horizontal axis, and means for indicating the angle in a vertical plane between the longitudinal axes of said telescope and gun; also in apparatus for electrically indicating said angle; also in apparatus for compensating for the error in the line of sight dueto the bodily movement of the gun, the target, or both; also in apparatus for compensating for the drift of the projectile when the gun is rifled; also in the various instrumentalities and combinations, mechanical and electrical, as hereinafter set fortl1,and more particularly pointed out in the claims.

In the accompanying drawings, Figure l. is a side elevation of my device applied to a ships gun. Fig. 2 is a rear elevation of the gun. to my apparatus for the purpose of supplying a correction to compensate for themovement of either the ship or the target. Fig. i is an end elevation thereof. V Fig. is a detail view ofthe drum of insulating material represented at 18 in Fig. 1. trical diagram illustrating the connections in the apparatus.

Similar letters and Iigurc's of reference indicate like part-s.

1 .represents so much of an ordinary naval gun as ,is necessary to illust ate the application of my device thereto.

2 is the gun-carriage.

3 is the gun-shield. On one side ot' said shield there is a shelf or ledge 4, upon which my telescopic sight is supported. I

5 is an ordinary telescope or spy-glass, preferably provided with-eross-hairs in its objec- -tive for the purpose of more accurately brin ging the line of sight upon the target. The telescope is mounted in trunnions 1l in the standard 6., Journaled in the standard C is a shaft', which carries a worm-wheel 8, and which on its outer end is provided with a hand-wheel 0. 'lhe telescope carries the Fig. 3 is a plan View of an attachment` Fig. G is an elec-- however, there is here shown a rack lil, connected to the gun, with which a pinion 1l cn-` gages. ]:ly turning the pinion ll by means of any suitable crank-handle the gun may be elevated and depressed as desired. Of cou rse this arrangement of rack and pinion 13 li is no part of my invention, inasmuch as the gun to which my device is attached may be elcvated or depressed by any suitable means.

Connected to the carriage 2 by means of the arm l5 is an lare 1U*. This are carries astrip of wire 1G or other conducting material, insulated from it. l, 17 is a contact-point of metal which is fastened upon the gun, but. insulated therefrom, and which bears against the wire 1G. v The are 16* is struck. from the trnnnion 12.0f the gun asa center., so that .when the breech oi' the gun is raised or lowered the contact-point 17 always bea-rs against said wire lo, the arc moving, of course,'in front of the contactpoint., The shaft 7 is made in two parts 7 -and 7, as shown in; Fig. 5, and these parts terminate in a drum 18, of hard rubber or other insulatingmaterial. In the periphery of the drum 1S iscut a spiral thread, and in this thread is laid a strip of metal or wire 19, which exactly corresponds to the wire 1G in its resistance from end to end. Of course this could bc produced by making the wire 19 precisely similar to the wire 1U in point of material, cross-section, and length.

. 2O is a eontact-arm which slides freely upon a rod 21, 'which is'supportcd in the insulated bracke 22 upon the table 23`of the appara-` tus. The contact-arm may be provided with a point, as shown in Fig. 5, which point 'always bears upon the wire 1'9. n .Consequently as'the whe'el 9, and hence the shaft 7, is rotated the arm 20 remains in the spiral groove of the drum 18, and of course follows that groove, this movement being permitted by the sliding oi the arm SO upenits rod or support For example,

A variety of same points on the respec'tive arc-wiresv 16 21. Therefore'eontaet between the arm 20 and the resistance-wire 19 is always maintained.

As best shown in Fig. 5, the ends of the Wire 19 on the drum 18 are connected, respectively, to insulated sleeves 19X on the sections 7 and 7b of the shaft 7. Secured upon the table 22 are two insulated contact-springs 24 25, and these bear, respectively, upon said insulated sleeves'. y

I will now describe the electrical connections in the apparatus. From the end fl' of the wire 16 a wire 26 extends to the contactspring 25. From the en'd c of the wire 16 a wire27 extends to the contact spring 2 Between the points and y of the wires 26 and 27 extends a wire 28, Awhich includes a battery 29. From the bracket which supports the arm 20, which bears on the wire 1.9 in the drum 1S, extends a wire 30 to a galvanometer 31.. From the galvanometer 31 extends another wire 32 tothe contactspoint 17. The relation of these connections will be more conveniently traced on l[he skeleton diagram,` Fig. 6. rlhis. diagram, as is obvious on inspection, represents the connections in the well-known Vheatstone-bridge relation; and here it will be obvious that when either of the are- wires 16 or 19 is moved al'ongthe contacts or 17, or, what is the same thing, if the contacts 2() or 17 be moved over the arc'- wires 19 or 16 the arms of the bridge will be lengthened or shortened, or, in other words, the resistances balanced in the bridge will be varied, and hence its equilibrium will be disturbed.

Now supposing that in Fig. 6 the parts marked 20 and 17 being the contact-points, are pivoted arms so arranged as to sweep over the arc-wires 16 and 1S), when these arms 20 and 17 stand parallel, touching the and 1f), clearly then the bridge willl balance and the galvanometer 3l will give no deection. moved so that its end meets the are-wire 19,

lf, however, the supposed arm 20 be at the point 2i of that wire, then, clearly, We

lhave lengthencd the'arm w24 of the bridge and shortened the-arm if", a-nd the bridge will then be thrown out of equilibrium and the galvanometer 31 will indicate the extent of this disturbance, which will of' course depend upon the resistance of the length of the wire 1f) included between' the original position of the arm 2() (full lines) and its new position. (Indicated by dotted lines.) Now, as the arc-wire 16 is assumed to be exactly like the arc-wire 1f) in point of resistance per unit length, and afs the electromotive force of the battery is, also assumed to be constant,

plainly if we move the supposed arm 17 to over an equal distance of the'fixed arc-wire 16,'or, in other words, to the point (l on that arc-wire, then the remaining` arms of the bridge will become, respectively, yd and dr, or, in other words, we shall have compensated for the disturbance `in the bridge made by the movement ot' the supposed-pivoted arm 20, and therefore the galvanolneter 3l will once more balance. The net result of all this is simply to show that the galvanometer 31 will always indicate zero whenever the two supposed pivoted. arms 2O and 17 are placed on corresponding points of their arc-v wires 16 and lJ-that is to say, whenever they are relatively parallel one t0 the otherbut Whenever they are not parallel then the galvanometer 31-will give a deflection which is proportional to the length of are-wire which isincluded between .the angle which they bear one to the other. Thus, if the arm 17 is left as shown in full lines andthe arm 2O be moved to make Contact at 24;, as shown bydotted lines, then the galvauoineter 31 will give a deflect-ion due to the .resistance included between the two positions of the arm 20. 0f course exactly the same thing would happen if the arms 2O and 17 of Fig. 'l 6, here supposed to be movable, were fixed and the arc- wires 16 and 19 were moved in front of the arms. v

Returning now to Fig. 1, it will be plain that when we rotate the wheel Qwe `move the wire 19 on the drum 1S beneath the couta-et-point 20, and at the same time by mea-ns of theworm S and rack 10 we turn the tele'- scope 5 on its trunnions. Y Therefore there is a relation between the length of wire which passes beneath the contact-point 2O and the angle over which the telescope 5 is turned.

Similarly when we elevate or depress the gun, which likewise turns it upon its trunnions 12, we at4 the saine time move the arc-wire 16 in front-ot the contact-point 17, so that there. is a relation between the extent of .angular elevation or depression ot" the gun and the length of the arc-wire 16 which moves in Contact with the point 17. Now if these parts be so adjusted, as in fact they are, that when the telescope 5- is elevated or depressed over a certain angle and the contact-point 2O therefore moves over a certain length of the wire 19, the gun, on being depressed or elevated over that same angle, will cause an equal vlength-of the arc-wire 16 to move in front of the contact-point 17.

Then clearly we shall have between the axis of the telescope and the axis ot' 'the gun the saine relations, with reference to the arewires 16 and 1f), as have the two supposed pivoted arms 17 and 20 in the diagram, Fig.

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(i. The shelf i is so placed on the shield that y when the axis of the bo're of the gun and the line of sight of the telescope are .parallel one tothe other the contact- points 17 and 20 will stand on the saine relative positions to their respective 'resistance-wires 16 and 19', and the galvanometer 31 will show no deflection, so that thus we have everat'tera means ot knowing, by the indication of the' galvanometer being zero, when the l'ine ofI sight of the telescope and the axis ot' the bore of the gun are relatively parallel. Of course these connections in practice. are adjusted once for all, and, therefore theuse of the device becomes,

in fact, exceedingly simple, for all that the observer has to do if the galvanometer .3l shows any deflection at all is to move either' gun or telescope on its trunnions until the Agalvanoineter shows no deflection, and then he knows that gun and telescope are parallel.

The relations of the parts now being established, I will explain their practical use. In order to make the projectile thrown by a gun reach its target, it is necessary to elevate the gun over a certain angle (dependent upon the distance of the target) above the line of sight drawn from the observers eye to the target; This distance may be determined by means of a range-finder or other apparatus especially adapted for that purpose, and the ordinary proceeding is, after the range has been determined or estimated, to suitably adjust a sight-bar on the gun, so that a notch in the upper part of this bar and a fixed projecting point or front sight at a distance therefrom along the gun shall be at a known angle tothe axis of the bore equal to the requisite angle of elevation ofthe gun. 'lhe observer ranges his eye so as to note the instant when these twoA points come into coineide'neewith the target, and then he lires the gun by any suitable means. Now oir-board ship this is a matter of consi deral )le difficulty and requires long training on the part of the person who is to direct the gun. It is an exceedingly diiiicult matter, especially when the ,.'hip ismoving, to catch the instantwhen `the sights and object come into alinenient'-,

because the pupil of the eye must be kept exactly on the line produced joining the front and the rearsights. lVha-t I accomplish in this present device is greatly to increase the accuracy and rapidity with which the sighting of the gun can be accomplished. This will be apparent from the `following description: For all practical purposes the axis of the telescope', when parallel with the axis of thebo'rc of the gun, may be considered as coincident. In other words, the displacement of the axis of the telescope above or laterally to the axis of the bore oi' the gun is so small with reference to the distance, over which the shot is thrown that any error due thereto may be neglected altogether. Assuming, For convenience, that in the beginning both giin and telescope stand parallel to the. plane ofv the deck, as shown in Fig. l, the galvanometer I3] then giving no deflection, the telescope 5 is brought toybear upon the object, so that the object comes at the intersection of its crosshairs. The necessary elevation to be given to the-gun, having been determined by the ran ge'jlinder, is known Corresponding thereto is a certain deflection of the galvanometer 31. 'lhe needle inust goto a certain point on the galvanometer-scale corresponding to the extent to which the bridge will' be thrown out of equilibrium by the known anddesired elevationof the gun. Instead of marking the galvanometer 3l for differences of potential dependent upon these changeait may as well be marked for yards correspondingto the po` needle shows that range, and this he does by the ordinary elevating or lowering apparatus of the gun. IVhen the galvanometer-needle does show that range, then he knows that the nrun is adjusted with regard to the line of sight already established at the proper angle to throw its shot over that distance. Of course in practice these observations are notv made by one man. One observer standing at the telescope and having in his hand ,the firing-button directs the telescope upon the object. An assistant operates the gun-elevatin g apparatus and watches the galvanonieter. All that the first operator has to do is to direct the telescope properly, and all that the second operator has to do is to elevate or depress the gun until the galvan oineter-ncedle indicates the desiredrange. lVhen that range is reached, the first operator fires the gun soon as the rolling ol? the ship brings the cross-hairs on the target. The iirst operator has nothing to do with the elevation of the gun or its adjustment for range. IIe maynot even know what the range is. The second operator has nothing to do with the sighting of the gun and cannot know when the gun bears on the. object. justment of sights ,orI inaccuraeyin alinenient of sights and object arepraetically obviated.

I new pass toanothcrpart ofmy invention, i

which consists in a meanswhich serves the double purpose ol verifying the accuracy oi 4the galvanometer reading and also of accomplishing the saine results alrcadystated by mechanical means in case ot any injury vto the electrical connections.l On the tace of the wheel E) (see Fig. 2) l make graduations and arrange in proximity to said wheel an indicating-point 33. Aswill readily be understood, by means of these graduations, which may be, say, in` degrees, I -can indicate the extent of elevationor depression of the tele- All errors from maladlOO scope 5. -I also attach to the gun a graduated are Si, the graduations onwhich correspond exactly to the graduations on wheel i). i On the arm 15 is a projection 35, which is parallel to the graduated are 84, 'and this projection may be likewis'egraduated in the saine units as the are 34. Now-the'relatior-i of 'the graduations on the wheel '9 and the fixed arc 34 on the gun are to be suoli that when the axis of the telescope isfparallel vto theaxis ot `the bore of`,tl1e-gun'the saine"l graduationmark on the wheel 9 which comes oppositethe 'pointer 33 will be the saine as the grad-uation-mark on 'the arc 34 which cornes oppo-l This For site the zero-point on the projection 35: zero-point may be located as desired.

convenience I have shown it as being slibstantially the horizontal lower edge of the `arm. l5 between the part which carries the jection 35 is also graduated, it is clear that by this means the angle between gun and telescope can be easily read. For example, if the reading of the wheel 9 is thrcedegrees and the two-degree mark ou the projection 35 is opposite the three-degree mark on the arc 34, then it is clear that the bore of the gun is inclined at an angle of two degrees to the telescope, and, similarly, if the' reading of the wheel i) is three degrees and the one-degree mark on the projection is opposite the tl'iree-degree mark on the arc 34, then the gun is inclined at an angle of one degree to the telescope, so that by means of these graduations on the wheel 9, the are Bt, and the projection 35 it becomes easy to give the gun and telescope any relative angular convergence that may be desired. v In this way also, clearly, these graduations give a check to the indications ot' the galvanolneter 3l, because, whatever may be the position of the telescope and gun, the

- mark on the projection 35 which is opposite to that mark on the arc 34 corresponding to the reading of the wheel should be the same as the indication in similar units of the galvanometer 3l, so that, further, even supposing all the electrical connections to -be destroyed, the gun and telescope can be laid parallel and the gun laid at any angle with reference to the telescope simply by observing the relation of the graduations -on the parts named. 0f course in practice the electrical apparatus is `much vmore rapid, and in other respects preferable but the value of the last-described arrangement as a check on the galvanometer and as a means of meeting casualties in action will be readily appreciated. 0f course instead of graduating 35 in degrees it may be graduated in yards' or meters once for all, because for any given gun, as already stated, the distance to which the shot Will go Ais entirely dependent upon the angular elevation of the muz` zle above the line of sight from gun to target. I now pass to another part of myin vention,

which consists in means for applying to the apparatus a correction for relative movement This of course involves p of gun and target. the following conditions; Either the target is fixed and the gun is movable, as in the case ,when the ship which carries the gun is under way, or the gun is fixed and the target is moving, which is the condition when the ship which carries the gun is stationary and tires, for example, at a movingship, and, third, when both the ship which carries the gun and the target which is fired at are moving one relatively t0 the other. 0f course in both lthe flrst and last cases the projectile will have not mcreljr the velocitydue toits `impelling charge, but also the velocity ot' the ship, acting in a different direction and tending to carry it in advance ofl the point aimed at. ln the second case, when the target is moving, the projectile will tend to fall in rear of the point aimed at. A single illustration will suice to make this clear. if, as in Fig. 7, the ship A fires at the ship l, and meanwhile advances to A', the shot will not strike B, but D, the distance l; D being merely equal to the 4distai'icc A A', so that the gun must in fact be pointed not directly at ll, but at an angle represented by l A C if rom the line of sight A l equal to the angle l) A l. This angle can be easily deduced for any and all speeds of ships, the speed or velocit y of the shot being known. In fact, itis always now deduced for everygun on board ship for use in, say, the ordinary sights, and it is usually called the correction for speed. The same is truc for the correction of the speed of the other ship 3, bearing in mind, of, course, that the correction must bein the opposite sense. I compensate 'for this in the following manner, (see Figs. 3 and riz) The base 22 of the instrument is secured to the shelf l. en the gunshield 3 by means of a strong vertical holt 3G, about which the table Q2 may berotated as on a pivot. In the table Q2 is cut a rectangular opening 3T, and on the shelf i there is a pin 258, having one side flat and the other side curved, which projects up through this opening. On the plate is a xed pin Si), and between the pins 3U 39 is interposed the bent spring 40. On the plate 22 is also a threaded support 4l, which receives the adwhich is provided with a graduated head 43. 'lhe end of the screw 42 bears against the flat side of the pin 3S. YWhen 43, the table or base-plate will be rotated around the pivot 3G, the spring i() acting in opposition to thc screw 2, so that this adjustment maybe mad-e in either direction. It is also clear that if the pitch of the screw 42' be known and the head 4:3 be appropriately grad-v uated the telescope 5, which is supported on the base-plate 22, may be turned to any desired angle by simply rotating the head 1S and noting the graduation. angle is seldom, if ever, as great asftwo degrecs,so that thc construction dcscri hed abundantly provides for this necessary limited extent of movement. It willbc readily under In practice this IOO the screw 42 is turned by means oi its head IIO stood that by this means thetelescope may be moved in azimuth to compensate for thel displacement oi' ci'lher the target or the ship which carries the jun. It is also plain that the microm-eter-head can be at once marked in units of speed instead ot' in degrees and minutes of ar'c.

There is also another small, but important,- correction necessitated by what is termed in gunnerythe drift of a projectile when .ired from a riled gun, this drift being a deviation from the line of fire to the right or the left, a right-handed riiiing causing the projectile t deviate to the right and aloft-handed ri fi ing causing the projectile to deviate toward the left. The distance to the right or left to which the shot is thus deviated increases with the distance to which the shot is fired, and it becomes necessary, therefore, to apply a correction which also increases' with the distance to which the shot is fired. lVith the ordinary sight-bar this correction is accomplished by placing the support of each sight-bar t one side of aline parallel to the boreof the gun from the front sight and by inclining it at an angle, so' that the rear sight-bar as it is raised does not rise in arvertical plane, but in one at an angle thereto. In my present device I provide for this correction in the followingl manner: Upon the base-plate 22 and in'proximity to the graduated head 43 is supported a small iixed graduated arc 44, which is graduated in degrees and minutes of arcor pret'- erably in terms of the ranges corresponding to these angles of drift. l In the ordinary use of a micrometer thercading is that of the graduation:D on the micrometerhead, such ris-13, which is opposite to a certain fixed zero or reference mark. In using the micrometerhead 43 I bring thc speed-graduation thereon opposite to the zero-mark on 44 in the supposititious case where the distance of the target is zero; but as the distance is of course not zero I bring the spoed-mark on 43 opposite to the graduation-mark on 44 which corresponds to the distance of the target. In case, for example, the speed of the ship were ten knots and the dista-nee of the target tiftcen hundred Yyards I bring the mark 10" on 43 opposite the mark 1500 on 44 5 and in ease the distance is two thousand yards and the speed zero, as when the iilrin g ship is at anchor an d the target stationary or when both are going in the same direction at equal speeds, I bring the zero -mark on 43 opposite the 200()77 mark on 44. Of course the relations of these parts depend upon known determinassv tions with which all persons skilled in the art are fully familiar and which need no description here, so that it is evident by this arrangement I am able,quickly and conveniently and with sufficient accuracy, to make at the same time the two corrections for speed and drift.

I claimo 1. The combination of the gun 1, movable on a transverse, horizontal axis, the elongated body 16 of conducting material and contactarm 17, the said body 16 .and arm 17 being movable with reference one to the other by the movement of said gun on its said axis; the telescope 5 also movable on. a transverse, horizontal axis and supported in proximity to said gun, shaft 7, intermediate mechanism,

for communicating motion from said shaft to said telescope, drum 18 on said shaft 7 carrying the elongated body 19, contact-arm 20 bearing on said body 19, a source of electricity, an electrical indicating apparatus and circuit connections arranged in Wheatstone bridge, substantially as described.

2. In combination with a telescope, 5, a gun and a support, 3, movable bodily With said gun and carrying said telescope 5, the baseplate 22 pivoted on saidl support and having .an opening, 37, a fixed pin, 38, on said suppqrt in said opening, an abutment, 39, on said base-plate 22, a spring, 40, interposed between said pin 3S and said abutment 39, a screw, 42, journaled on said base-plate 22 and bearing upon said pin 38, substantially as described.

In combination with a telescope, 5, a gun and a support, 3, movable bodily with said gun, a base-plate, 22, carrying said telescope pivoted on said support and having an opening, 37, a fixed pin, 38, on said support in said opening, an abutment, 39, on said base-plate 22, a spring, 40, interposed between said pin 3S and said abutment 39, a screw, 42, journaled on said base-plate 22 and bearing upon said pin 3S, and a micrometer-head, 43, on said screw and a fixed mark or index in proximity to said head: the said head being suitably y graduated to enable the telescope to be adj usted in azimuth to compensate for displacement of thelprojectile due to the movement of the gun, orsaid distant object, or both, substantially as described.

4. In combination with a telescope 5, a baseplate, 22, carrying said telescope, pivoted on said support and having an opening 37, a pin 38 on said support in said opening, an abutment S9 on said base-plate, a spring 40 interposed bet-wcen said pin 3S and said abutment, 39, a screw 42 j ournaled on said base-plate and bearingupon said pin 38, a micrometer-head 43 on said screw and a fixed, graduated arc 44 in proximity to said micrometer-head: the

said head 43 being suitably graduated to en-v able the telescope to be adjusted in azimuth to compensate for displacement of its line of sight to a distant object due to the bodily movement of said telescope or said distant Object, or both, and the said fixed are 44 being suitably graduated to allow of adjustment of said telescope in azimuth to compensate for drift of the projectile thrown from a gun, substantially as described.

WM. ARNOUX, JOHN C. SANDERS.

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