Improvements in and relating to Apparatus for Sighting Guns.
Year: 1893

page_text: Date of Application, 24th May, 1893-Accepted, 29th July, 1893
COMPLETE SPECIFICATION.
[Communicated from abroad by THE AMERICAN RANGE FINDER COMPANY,
a corporation organized and existing under the laws of the State of West
Virginia, and having its principal place of business at corner of Greenwich
and Thames Street, in the City of New York, United States of America.]
Improvements in and relating to Apparatus for Sighting Guns.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45 Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
The invention is an improved apparatus for directing or sighting guns upon
distant objects. It also includes devices for correcting the line of sight to allow
for displacement of the projectile due to movement of the gun or of the object or
both, and, if the gun is rifled, due to drift of the projectile.
Fig. 1 is a side elevation of the device applied to a ship's gun.
elevation thereof.
Fig. 3 is a plan view of the device for compensating for speed.
elevation thereof.
Fig. 5 is a detail view of the drum of insulating material.
Fig. 6 is a diagram showing the connections in the apparatus.
Fig. 7 is a diagram illustrating the correction for speed.
Fig. 2 is an end
Fig. 4 is an end
Fig. 8 shows the application of the device in elevation to a rapid-fire gun.
Fig. 9 is a plan view thereof.
Fig. 10 represents the device of Fig. 8 as arranged to correct for drift.
Similar numbers and letters of reference indicate like parts.
7 is a
15 is an
1 is a naval gun. 2, its carriage. 3, the gun shield. 4, a shelf or ledge on
the shield. 5, a telescope mounted on trunnions, 11, in the standard 6.
shaft having a worm wheel, 8, and which engages with a rack, 10, carried by the
telescope; so that, by turning wheel 9 on shaft 7, the telescope may be turned
on its trunnions and so elevated or depressed. 12 are the gun trunnions.
13 and 14 are respectively a rack and pinion for elevating or depressing the
gun. Any other known device for this purpose may be substituted.
arm on the carriage 2 which carries an arc, 16", which arc is concentric with
the gun trunnion. On the arc 16* is a wire, 16, against which bears an insulated
point, 17, secured to the gun. Shaft 7 is made in two parts, 7 and 7b, Fig. 5,
which terminate in a drum, 18, of rubber. On the drum is a spiral thread in which
is a wire, 19, exactly corresponding to wire 16 in its resistance from end to end.
20 is a contact arm sliding on rod 21, which is supported on insulated bracket 22
on the base or table, 23, of the apparatus. When wheel 9, and hence shaft 7, is
rotated, a point carried by arm 20 entering the groove of drum 18 follows that
groove; the arm 20 sliding on support 21. The ends of wire 19 are connected to
insulated sleeves 19* on the insulated sections 7 and 7 of shaft 7. Upon these
sections bear two insulated contact springs, 24 and 25, which are secured upon
table 23.
The electrical connections are as follows: From the ends of wire 16 extend
wires, 26 and 27, respectively to contact springs 25 and 24. Between the points x
and y of wires 26 and 27 is a wire, 28, including a battery, 29.
From arm 20
extends wire 30 to through bracket 22 galvanometer 31. From contact point 17
to galvanometer 31 extends a wire, 32. From Fig. 6 it is seen that the relation of
these connections is that of a Wheatstone bridge, and that when either of the arc
wires 16 or 19 is moved along the contacts 20 or 17, or, what is the same thing, if
D

page_text: the contacts 20 or 17 be moved over the wires 19 or 16, the resistances balanced in
the bridge will be varied, and hence its equilibrium will be disturbed.
Assuming, for convenience, in Fig. 6, that the parts 20 and 17 are movable and
are pivoted arms, the galvanometer 31 will always indicate zero whenever these
arms 20 and 17 are placed on corresponding points of the arc wires 16 and 19,
these wires being exactly similar in point of resistance of unit length; that is to
say, whenever the arms are relatively parallel one to the other, the galvanometer 31
will indicate zero, but whenever they are not parallel, then the galvanometer 31
will be deflected proportionately to the length of arc wire which is included between
the angles which the arms bear one to the other. Thus, if the arm 20 be moved to
make contact at 24 (dotted lines), then galvanometer 31 will give a deflection due
to the resistance of are wire 19 included between the two positions of arm 20.
When the wheel 9 is rotated, the wire 19 is moved beneath the contact arm 20,
and the telescope 5, at the same time, is turned on its trunnions; therefore there
is a relation between the length of wire which passes beneath the contact point 20
and the angle over which the telescope is moved. There is also a relation between
the extent of angular movement of the gun on its trunnions and the length of arc
wire 16 which moves in contact with point 17. The shelf 4 is so placed on the
shield that when the axis of the bore of the gun and the line of sight of the
telescope are parallel, the contact points 17 and 20 will stand in the same relative.
positions to their respective resistance wires 16 and 19, and the galvanometer 31
will show no deflection; so that thus we have ever after a means of knowing, by
the indication of the galvanometer being zero, when the line of sight of the
telescope and the axis of the bore of the gun are relatively parallel.
The apparatus is used as follows: In order to cause a projectile from a gun to
reach a distant object, it is necessary to elevate the gun over a certain angle
dependent upon the range above the line of sight from the observer's eye to the
target. This distance may be found by a range finder, for example. Practically,
the axis of the telescope, when parallel with the axis of the bore of the gun, may
be considered as coincident. The gun and telescope being laid parallel, the
galvanometer gives no deflection. The telescope 5 is then brought to bear upon
the object.
The necessary elevation to be given to the gun for the determined
range is known, and corresponds to a certain deflection of galvanometer 31. The
needle must go to a certain point on the scale corresponding to the extent to which
the bridge will be thrown out of equilibrium by the known and desired elevation.
Instead of marking the galvanometer 31 for differences of potential dependent upon
these changes, it may be marked for yards or meters corresponding to the potential
differences; therefore, the observer, knowing the range, has simply to elevate or
depress his gun so that the galvanometer needle shows that range, and then he
knows that the gun is placed, with regard to the line of sight already established,
at the proper angle to throw its shot over the determined distance. In practice,
one observer, standing at his telescope and controlling the means of firing the
gun, directs the telescope upon the object; and, as soon as the rolling of the
ship brings the target upon the cross-hairs of the telescope, he fires the gun. An
assistant operates the gun-elevating apparatus and watches the galvanometer.
In order to verify the indications of the galvanometer and provide a substitute
apparatus in case of injury to the device above described, the following arrange-
ment is employed: On the face of wheel 9 are graduations, and near said wheel is
an indicating point, 33. The extent of elevation or depression of telescope 5 is
shown by these graduations. On the gun is a similarly graduated arc, 34, and on
the arm 15 is a projection, 35, similarly graduated and parallel to arc 34. The
relation of the graduations on the wheel 9 and the fixed arc 34 on the gun are such
that, when gun and telescope are parallel, the mark on wheel opposite pointer 33
is the same as the mark on arc 34 opposite the zero point on projection 35. This
zero point may be the lower edge of arm 15 between the part which carries arc 16*
and projection 35; hence, when pointer 33 indicates two degrees on wheel 9 and
the zero mark on arm 15 is opposite the two degree mark on arc 34 which is on

page_text: the gun, then telescope and gun will be parallel; and so on for all other corre-
sponding graduations. As projection 35 is also graduated, by this means the angle
between gun and telescope can be read. Thus, if wheel 9 reads three degrees and
the two degree mark on 35 is opposite the three degree mark on 34, then the bore
of the gun is inclined at an angle of two degrees to the telescope. By this means,
the gun and telescope may be given any relative angular convergence, and the
graduations are a check on the indications of galvanometer 31; because, whatever
may be the position of the telescope and gun, the mark on 35 which is opposite to
that mark on 34 corresponding to the reading of wheel 9 should be the same as the
indication of galvanometer 31. Instead of graduating 35 in degrees, it may be
graduated in yards or meters once for all.
In Fig. 7, if the ship A fires at the ship B and meanwhile advances to A¹, the
shot will not strike B, but D; so that the gun must be pointed at an angle, BA C,
from the line of sight A B equal to the angle DA' B. This angle is easily deduced
for any
and all speeds of ships, the velocity of the shot being known. The same
is true for the correction, in the opposite sense, of the speed of the other ship B.
To compensate for this, I secure the base, 23, of the instrument to the shelf 4 by a
bolt, 36, Fig. 3, on which the base 23 may be turned, as on a pivot. In 23 is an
opening, 37, which receives the pin 38 on shelf 4. On 23 is a pin, 39, and between
pins 38 and 39 is placed a bent spring, 40. An adjusting screw, 42, passes through
This screw bears on
a support, 41, on base 23, and has a graduated head, 43.
pin 38, and when it is turned, the plate 23 will be rotated around the pivot 36.
The pitch of screw 42 being known, and the head 43 being appropriately graduated,
the telescope 5 may thus be turned to any angle. In practice, this angle is seldom
as great as two degrees. This movement of the telescope in azimuth compensates
The
for the displacement of either the target or the ship which carries the gun.
head 43 can be marked in units of speed, if desired.
In order to compensate for the deviation of a projectile during its flight, due to
the rifling of the gun, or, as it is termed, the "drift," I attach to base plate 23, and
in proximity to the head 43, a small fixed arc, 44, which is graduated in degrees
and minutes, or, preferably, in terms of the ranges corresponding to the angles of
drift. I then bring the speed mark on 43 opposite the graduation mark on 44
which corresponds to the distance of the target. Thus, if the speed of the ship is
ten knots, and the distance of the target 1500 meters, I bring the mark 10 on 43
opposite the mark 1500 on 44; and in case the distance is 2000 meters and the
speed zero (as when the firing ship is at anchor and the target stationary, or when
both are going in the same direction at equal speeds), I bring the zero mark on 43
opposite the 2000 mark on 44. The relations of these parts depend upon known
determinations familiar to artillerists generally, and need no further description
here.
Referring now to Figs. 8, 9 and 10, there is here illustrated the combination of
my sighting device with that class of guns which are arranged to recoil in the
direction of their line of fire, and in this respect are different from guns which,
whatever may be their angular position, always recoil along the plane of the deck
or other support on which they rest. The so-called "quick-fire" guns belong to
this class. The gun A" is supported by its trunnions in blocks, B, which move
upon slides, C¹, of the saddle D". The saddle D has trunnions, E", which are
received in bearings, F", of the upright standard G". The standard G" may be
rotated on its vertical axis so as to train the gun in azimuth, and the saddle Du
turns on its trunnions E" so as to raise or lower the muzzle of the gun. K" is the
lever for moving the breech block, H" the firing trigger, I" the shoulder piece and
J the handle for moving the gun.
Upon the saddle D" is a shelf which supports the sighting apparatus, the general
construction of which is similar to that already described, and is correspondingly
numbered. It is obvious that the axis of the bore of the gun is always parallel to
the slide on the saddle; so that practically the upper edge of the saddle on which
the sighting device rests may be regarded as the axis of the bore; so that it is only

page_text: necessary to consider the angle of the telescope 5 to its base 23. In practice, the
operator places the telescope 5, by means of the hand-wheel 9, so that its axis is
parallel to the plane of its base. Then he elevates the sight end of the telescope
over an angle corresponding to the desired range. This angle will be, of course,
the angle to which the gun must be elevated in order to throw its projectile over
that desired range. Then he lowers the rear end of the saddle until the telescope
comes on the object, when, of course, he must then have raised the object end of
the telescope, and hence the gun itself, over the proper angle. When the object
appears on the cross-wires of the telescope, the gun trigger is pulled. If the vessel
is rolling or pitching, that action is utilized as follows: The observer sets his
telescope as before; but, instead of actually lowering the shoulder end of the
telescope, he merely waits immovably until the upward roll of the ship carries
the telescope upward until the object is seen through it. Then he fires the gun as
before. The placing of the telescope parallel to the gun is easily done by simply
bringing the graduation on its wheel 9 to a definite mark in which the angle at
which the telescope is laid determines, of course, the elevation angle of the gun.
It is to be understood that the invention comprehends the combination of a telescope
with any projection to the gun carriage which has motion coincident with the gun
in elevation and train, but which does not recoil with the gun. For instance, the
telescope may be secured to a bar pivoted to a fixed part of the carriage in line
with the trunnions and supported at its rear end on the breech of the gun.
In this device, in order to provide for drift, I incline the trunnions whereon the
telescope 5 is supported substantially as shown in Fig. 10. In this way the vertical
cross-wire in the telescope is inclined to a vertical plane, and hence it has the same
motion as the inclined sight-bars commonly employed on guns for making this same
correction. This inclination of the telescope is effected by simply cutting away the
base of the instrument at an angle.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondents I declare that what I claim is
1. The combination of a telescope or sight-bar and a gun, each movable about a
transverse, horizontal axis and graduated scales and pointers arranged in connection
with gun and telescope for indicating the angle in a vertical plane between the
longitudinal axes of telescope and gun.
2. The combination of a telescope or sight-bar and a gun, each movable about a
transverse axis, and connected in Wheatstone bridge circuit similar bodies of
conducting material, a source of electricity, and an electrical indicating instrument;
the aforesaid parts being constructed so that the relative movements of gun and
telescope may modify the balance in the circuit, and cause the electrical indicating
instrument to show the angle in a vertical plane between the longitudinal axes of
said telescope and gun, or the range thereunto corresponding.
3. The combination of a telescope or sight-bar, a gun recoiling in the direction
of its line of fire and a support for said telescope and said gun which does not
recoil with the gun; the said gun and telescope being each movable about a
transverse axis, and operating as and for the purpose described.
4. The combination of a telescope or sight-bar, and a gun, each movable about
transverse, horizontal axis and provided with means for showing the angle in a
vertical plane between the longitudinal axes of telescope and gun, and with devices,
as described, for displacing the line of sight of the telescope laterally in order to
apply corrections for speed and for drift.
Dated this 24th day of May 1802
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.