Improvements in Sighting Gear for Ordnance.
Year: 1897

page_text: Date of Application, 17th Apr., 1897-Accepted, 19th June, 1897
Improvements in Sighting Gear for Ordnance.
I, Lieutenant-Colonel Sir GEORGE SYDENHAM CLARKE, K.C.M.G. and GEORGE
HENRY BANISTER, Civil Engineer, both of the Royal Arsenal Woolwich, in the
County of Kent, 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:
-
This invention relates to improvements in sighting gear or apparatus for ordnance,
the said apparatus being so constructed that the sights, besides being available for
use in laying the gun in the ordinary manner, are adapted to be automatically
Either mode of
adjusted to the range of any object on which the gun is directed.
using the sights can be adopted at will, the change from one mode to the other being
effected very conveniently and expeditiously.
In the accompanying drawings we have illustrated two constructions of sighting
apparatus embodying our invention.
Figure 1 is a sectional side elevation of the sighting apparatus and shows so much
of the gun and its mounting as is necessary illustrate the construction and mode
of operation of the said apparatus.
Figure 2 is a side elevation of a modified form of the sighting apparatus.
Figure 3 is a transverse section on the line x, x Figure 2 looking from the rear,
and drawn to an enlarged scale, and
which
Figure 4 is a section taken at right angles to the plane of section in Figure 3.
Like letters of reference denote corresponding parts in the several figures.
The fore and rear sights are carried at the end of a hinged or pivoted bar
may be adjusted to suit any estimated range by worm gear controlled by a hand
wheel the desired range being indicated by graduations on a drum c.
a,
In sighting apparatus wherein the fore and rear sights are carried at the extremities
of a pivoted bar the said bar has heretofore been hinged directly to the gun cradle or
carriage, but according to our present invention we interpose between the bar a and
the cradle a movable arm, that is to say, we binge or pivot the bar a at a¹ to a bent
arm d which is pivoted at d' to a carrier bar e fixed to the gun cradle by the screws e¹ el.
Also pivoted at dis another arm or leverf which is controlled as hereinafter
described and which can be locked to the arm d by a pin f¹ so that the two arms d, f
will turn together about their common pivot d'. When the sights are in use in the
ordinary manner for sighting objects at estimated ranges, the locking pin f'is
removed and by the thrust of a spring contained in the case h, the arm d is brought
into contact with an adjustable screw-stop j, and then the arm d and the carrier bar e
will move together with the gun cradle as one piece and the action of the sights is in
effect the same as that of ordinary sighting apparatus. The gear controlled by the
hand wheel for raising and lowering the sight bar a independently of the arm dis
carried by the rear end of the said arm d.
For the purpose of adapting the apparatus to work so that in bringing the sights
into alignment with the object or target the gun will be automatically brought to the
required angle of elevation, the following gear is provided. The lower end of the
lever is furnished with a pin preferably provided with an antifriction roller f that
works in the groove of a cam g which is attached to the gun carriage. The cam is
accurately designed and constructed to control the position of the pivoted sight bar a
as follows, that is to say, the arm d having been lowered until it bears on the stop j,
the lever is locked to the arm d by the pin f'. Thereupon the movement of the

page_text: 2
gun about its trunnions will cause the roller to assume different positions in the
cam groove and so automatically produce the desired relative movement of the gun
and sights.
For accurate shooting over the sea it is absolutely necessary to provide for the
adjustment of the apparatus according to the variations of the target level due to
the ebb and flow of the tide. For effecting such adjustment the cam g is hinged to the
gun carriage at g', and the upper end of the cam is controlled by an eccentric k which
is operated by a lever l. is a scale and is an index for denoting thereon the
positions to which the lever / must be set to adapt the aim to the height of the tide at
the time when the gun is being fired, that is to say, by adjusting the lever the
position of the cam g relatively to the sighting gear gives the necessary corrections
for variations of the tide level.
1
For adjusting the aforesaid gearing to either method of sighting, it is necessary to
remove or to insert (as the case may be) the locking pin and as this is within the
armoured shield some delay may be thereby occasioned. In order to avoid this delay
and to provide a more accessible and readily operated method of adjusting the
sighting gear we have devised the alternative construction shown in Figure 2. The
cam for automatically controlling the position of the sights and the means for making
the corrections for variations in the tide level are the same as in Figure 1. The sight
bar a and the arm d are hinged or pivoted on a common pin d¹ at the end of the
carrier bar e which as previously described is secured to the cradle. The arm & in
this instance consists of one part only and not of two parts as in the first arrangement.
The said arm can at will be coupled to the sight bar a, or set free from it, in a manner
to be presently described. Moreover the gear operated by the hand wheel b may be
adjusted to work the sight bar a in relation to the gun, or may be released as herein-
after described. The act of adjusting the gear operated by the wheel b so that it will
work the pivoted bar a also serves to disconnect the arm & from the sight bar, so that
the sights will then act in the ordinary manner, as above described. The release of
the gear operated by the wheel b which in this modification is carried by the bar e
connects the sight bar a to the arm d so that the apparatus then becomes automatic as
above described.
The mechanism for effecting these changes is as follows viz.:-The adjustments are
made by means of the hand lever or trigger m which is carried by and is free to
rotate in a bearing n. The spindle m¹ of the trigger has an eccentric at m² and
about this eccentric and carried by it is a piece o shaped to bear against the periphery
of a ring p and so arranged that by turning the trigger m and thereby the eccentric m²
the piece o can be pressed against the ring p. In one position of the trigger the
ring p is jammed or held fast and prevented from rotating while in the other position
of the trigger the ring is free. This ring forms part of the worm wheel and pinion
gear for adjusting the sights in the ordinary use of the same.
When the hand wheel & is rotated, the worm wheel q is turned by the worm b' which
is formed or fixed on the spindle of the hand wheel b; the said worm wheel carries
with it a bevil wheel which is geared with bevil wheels r, r carried on radial
axles mounted in the ring p. The wheels r, r are also geared with a bevil
wheels which is fixed on the spindle t¹ of a spur pinion t. The said pinion t is
directly geared with the arc u which is fixed to one end of the sight bar a. Therefore,
if the hand wheel is turned while the ring p is jammed or held fast, the
gearing 9rs will cause the pinion t to rotate and thereby the sights on the sight
bar a will be set to the desired range which will be shown on the indicator drum c.
On the contrary if the ring p is set free, the arc u on the sight bar a cannot be
actuated by the hand wheel b, as the wheels q and then rotate freely on the
spindle t'.
The spindle m¹ of the trigger is made hollow to receive a shaft which is free
to move longitudinally and to oscillate slightly, but is unable to rotate independently
of the said spindle. This shaft v is connected at its upper end to a catch w which
is carried by the rear end of the sight bar a, and the said shit controls the catch so that
in one position of the trigger the catch is caused to engage with the jaws w¹ formed at

page_text: the rear end of the lever d and in the other position of the trigger the catch is set.
free from the said jaws. When the catch is engaged with the jaws w¹ the sight bar is
caused to turn with the arm d and the automatic adjustment of the sights is thereby
effected. The catch w is formed on a spindle y (Figure 3) that can turn in a sleeve y¹
carried by the sight bar. The lower end of the said sleeve has formed on it a helix or
screw thread y which engages with suitable jaws y (Figure 4) fixed to the sight
bar a. These jaws form, in effect, a nut for the helix or screw thread to work in..
The upper end of the sleeve y¹ is connected to a graduated drum y having a milled
head by which it can be conveniently turned. It will be seen that rotation of the
graduated drum y' will raise or lower the sight line, relatively to the catch w and we
thereby provide for the correction of any errors in the shooting that may be due to.
atmospheric conditions or to varying qualities of the powder. A pointer or index y'
is arranged at the side of the drum.
With the arrangement above described the adjustments for the automatic or..
ordinary use of the sights are effected as follows, that is to say-On the one hand by
placing the trigger m at one end of its movement the catch w is engaged with the
jaws w, w and the ring p is set free and the mechanism is thus adapted for automatic.
sighting. On the other hand by setting the trigger m at the other end of its
movement the catch w is set free and the ring p janimed, the mechanism being then
arranged for ordinary sighting. The trigger m is in a convenient position for operation,
by the gunner and can be instantly moved from one position to the other.
The above described combination whereby we provide for either the automatic-
sighting or the ordinary sighting of guns, permits a ready and accurate use of the sights
when firing at objects elevated above the sea level, say, for example, the tops of a warship.
That is to say, when the apparatus is set for automatic sighting the sight line may be
laid on the water line of the vessel, the gun being thereby brought to the proper-
elevation for the range of such vessel, and when the gun is so laid, the position of the
trigger m may be changed to set the apparatus for ordinary sighting, and the sight
line may then without further adjustment of the sights be laid on the ship's tops the
correct elevation being thereby given to the gun.
Having now particularly described and ascertained the nature of our said inven-.
tion and in what manner the same is to be performed, we declare that what we-
claim is :-
:-
1. Sighting apparatus so constructed and combined with a gun that the same fore
and rear sights can be used at will for either ordinary or automatic sighting, substan--
tially as described.
2. The combination of the pivoted sight-bar with a lever pivoted to the carrier bar
and capable of being locked to and released from an arm by the agency of which the-
automatic adjustment of the sights is effected, substantially as described.
3. The combination with the pivoted arm d of the cam g secured to the gun
cradle and engaging with the said arm, substantially as described, and for the
purpose specified.
4. The means for adjusting the cam 9 to correct the sighting gear for variations in.
the tide level, substantially as described.
5. The means for adjusting the sight line relatively to the catch w for the correction
of errors due to atmospheric or other conditions as above set forth.
6. The apparatus constructed substantially as described with reference to Figure 1
or to Figures 2, 3 and 4 of the accompanying drawings, and operating as, and for the.
purposes, specified.
721 1
1007
HASELTINE, LAKE & Co.,
45 Southampton Buildings, W.C., Agents for the Applicants.