Improvements in Apparatus for Aiming or Directing Ordnance.
Year: 1888

page_text: Date of Application, 19th Sept., 1888
Complete Specification Left, 19th June, 1889-Accepted, 3rd. Aug., 1889
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Aiming or Directing Ordnance.
I, HUBERT HENRY GRENFELL, of Elswick Works, Newcastle on Tyne, Captain R.N.
do hereby declare the nature of this invention to be as follows:-
According to this invention the inclination of the line of sight to the axis of the
gun or line of fire is adjusted not as is usual by moving one of the sight points
relatively to the other but by the movement through a socket or guide of a curved
stem or part on which both the sights are carried. In this manner both the vertical
and lateral direction is obtained.
The construction is as follows:-the sights are carried upon a single support which
is a circular are working in a guide fixed to or moving with the gun. As the arc is
then moved in this guide, the line of sight is inclined, in a vertical plane, more or less
to the axis of the bore of the gun.
In order to allow the gun to be inclined in a horizontal plane to the line of sight
to allow for wind or drift the sights are mounted on a curved slide working in a
curved guide carried by the circular support and a rack and pinion is provided to
traverse the slide along the guide. In order to correct for the movement of the gun
and object when either or both of them are in motion, in place of fixing the last
mentioned guide directly to the circular support I make it in the form of a curved
slide inovable by a rack and pinion in a curved guide fixed to the support--all the
slides are graduated.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Aiming or Directing Ordnance.
I, HUBERT HENRY GRENFELL, of 5 Astwood Road, Cromwell Road, in the County
of Middlesex, late Captain R.N. 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:
My invention relates to apparatus for aiming or directing ordnance.
In sighting apparatus as heretofore constructed, the required inclination of the line
of sight relatively to the longitudinal axis of the gun or line of fire is obtained by
moving one of the sights or sight-points relatively to the other sight or sight-
point. But according to my invention I provide for obtaining the required inclination
of the line of sight by the simultaneous adjustment of two sights or sight-points about
an imaginary pivot or axis. When I speak of two sights or sight-points, I include
amongst other devices the eye-glass and object-glass of a telescope."
My said invention, moreover, comprises the construction of a sighting apparatus
in such a manner that the adjustments for lateral deflection and for the speed and
course of a moving object against which the gun may be directed, can be effected
separately or independently of each other on the same sight-bar.
In the accompanying drawings
Figure 1 is a side elevation of a gun fitted with an ordinary sighting apparatus.
Figures 2, 3 and 4 are diagrams hereinafter explained.
Figure 5 is a side elevation of one form of my improved sighting apparatus.
Figure 6 is a rear elevation of the said apparatus, some of the parts being removed,
and
Figure 7 is a plan of the said apparatus, the telescope hereinafter mentioned being
removed.

page_text: The sighting of ordnance is usually effected by means of a fixed fore-sight on or
near one of the trunnions, and an adjustable rear sight on the breech carried by a
straight bar provided with a graduated scale.
Taking the case of a gun with a fixed foresight on one of the trunnions, as at A,
and with an adjustable straight-bar rear sight on the breech of the gun, as at B,
Figure 1; if with the point A as a centre and with the distance A B as a radius, an
are of a circle be described as in Figure 2, this are will represent approximately
the path in which the head of the rear sight will move when the gun is turned
about its trunnions for vertical pointing or elevation. If this arc be divided into
equal parts BC, CD, DE, each subtending an angle of say ten degrees, and the
lines AC, A D, A E be prolonged until they intersect the vertical line B H, which
indicates the position of the sight-bar-when the gun is horizontal, the distances B F,
F G, G H will represent respectively the distances through which the sight-bar must
be raised to correspond with the several angles of elevation subtended by the arcs
B C, C D, D E. It will be seen that these distances are not equal but continually
increase, that is to say, the greater the angle of elevation of the gun, the greater is
the distance through which the sight-bar must be moved to correspond with a given
angular movement of the gun about its trunnions. The divisions of the graduated
scale on the sight-bar must, therefore, be at unequal distances apart, those at the upper
part of the bar being much nearer to each other than those at the lower part
thereof.
Assuming the gun to be elevated to the position A E (Figure 3), it will be necessary
to raise the straight sight-bar from E to Bi in order to bring the line of sight into a
horizontal position, B₁ E being equal to B H.
Now according to my invention, instead of a straight bar as at BH Figure 2 I
employ a curved bar as at B E (Figure 4) having at its head a telescope or other
device comprising two sights or sight-points J J and so arranged upon a horizontal
bar K that a straight line passing through the two sight-points or through the axis of
the telescope will, if extended, pass through the point A, when the sight-bar is in the
position indicated in Figure 4. It is evident that this straight line will also pass
through the point A when the curved bar is adjusted to any other position about an
imaginary pivot or axis extending through the point A. It follows, therefore, that
the fixed fore-sight may be dispensed with. It is evident, moreover, that the curve
of the sight bar may, if desired, form an arc of a circle having a radius longer or
shorter than A B as may be found most convenient, and that the centre or imaginary
pivot or axis about which the sight-bar moves may be situated either within the
length of the gun or beyond the muzzle thereof, the line of sight always extending
through the sight-points or through the axis of the telescope carried by the sight-
bar.
By thus mounting two sights upon a curved sight-bar arranged to move about an
imaginary pivot or axis, I am enabled to use sight-bars having the same curvature
for guns of different sizes, with the following advantage, viz. :-When the distance
A B is limited, as with the ordinary sighting apparatus on short guns, the sub-
divisions on the sight-bar for degrees and yards must be inconveniently minute and
are consequently difficult to discern; moreover, in the case of large guns, if the
distance A B great, the subdivisions must be correspondingly large, thus necessi
tating the use of a bar of inconvenient length. But by my invention, such a cur-
vature of the sight-bar may be adopted as will give, in all cases and with guns of
any size, the length of subdivisions of the graduated scale and consequently the total
length of bar which may be found most suitable for general use.
I provide in a similar manner to that above described for the horizontal adjustment
of the line of sight, to obtain the required inclination of the same relatively to the
line of fire to allow for drift or deflection of the projectile by the wind, or for the
speed of a ship or vessel on which the gun.is mounted, or for the speed and course
of an enemy's ship or other object against which the gun is directed.
For this purpose, the horizontal bar carrying the sights is mounted on a horizontally
curved bar or slide working in a grooved guide carried by the vertical sight-bar, or by

page_text: another horizontally curved bar or slide arranged to work in a grooved guide on the said
vertical sight-bar; racks and pinions or other suitable devices are, moreover, provided
for effecting the adjustment of the said slides.
In Figures 5, 6 and 7, I have shown how my said invention may be conveniently
and advantageously canried into practice.
Like letters indicate corresponding parts throughout these figures.
a is the curved sight-bar which is provided with a rack a' and which is arranged
in a suitable guide or socket a² attached to, or movable with the gun; the said guide
or socket is provided with a pinion geared with the said rack; or other suitable
means are employed for adjusting the said sight-bar in a vertical plane about an
imaginary pivot or axis.
b is a telescope which is mounted on the curved bar a as follows, that is to say, the
said telescope is held in brackets e which are secured in any convenient manner to a
horizontal bar or plate d, so that the telescope can be readily removed and replaced.
Ordinary sights e, c² are also mounted upon the said bar or plated. This plate is..
attached to a horizontal segmental slide e arranged to move in a groove or channel f¹
in another horizontal segmental slide f. The segmental slide is arranged to move
in a groove or channel g₁ in a guide g firmly attached to the upper end of the curved
bar or vertical segmental slide a. The segmental slide is provided with a rack.ƒ³
with which is geared a pinion.h carried by the plate or bar d and provided with a
milled head or wheel h¹ for facilitating its operation. By means of this rack and
pinion, the plate or bar d, the telescope carried thereby and the segmental slidee may be
adjusted relatively to the segmental slidef. The segmental slide fis arranged to be
adjusted with the bar d, the telescope carried thereby and the slide e relatively to the
guide by means of another rack and a pinion operated by means of a milled
wheel j¹. The segmental slide fis formed with a slot, Figure 6, and with a graduated
scale as shown. The segmenta! slide is provided with a projection e' which extends
through the slot 2 and has formed upon it an arrow-head or pointer. A similar.
arrow-head or pointer is also formed on the guide g.
By turning the milled wheel ' in either direction, the segmental slide e with the
bar d'and telescope b will be moved in the corresponding direction relatively to the
graduated slide, thus effecting the required adjustment of the sights in a horizontal
plane about an imaginary pivot or axis to allow for the speed of the ship on which
the gun is mounted, or for deflection by the wind. By turning the milled wheel j' in
one or the other direction, the slide and the parts carried thereby will be moved
and the graduated scale thereon adjusted in the corresponding direction relatively to
the arrow-head on the guide g. The sights may thus be adjusted about the imaginary
pivot or axis to allow for the speed and course of an enemy's ship or other object
against which the gun is directed. A single graduated scale thus serves to indicate
these separate or independent lateral or horizontal adjustments. Moreover by these
means, after the sights have been adjusted to allow for deflection by the wind and
for the known speed of the ship on which the gun is mounted, the required adjust-
ment to allow for the estimated speed and course of an enemy's ship, at the time
when the gun is about to be fired, can be effected independently of and without
disturbing the previous adjustment.
It is obvious that the construction of my improved sighting apparatus can be
modified without departing from the nature of my invention. For instance, the
vertical curved sight-bar may be employed with devices other than those above
described for effecting the lateral or horizontal adjustment of the sights. Moreover,
the lower borizontal slide may, if desired, be used for the adjustment to allow for
deflection, and the upper horizontal slide for the adjustment to allow for the speed and
course of an enemy's ship. Or I can use means other than those above described
for effecting the separate or independent adjustments for deflection and for the speed
and course of a moving object against which the gun is directed.
By constructing a sighting apparatus in the manner hereinbefore described, I
provide for enabling the telescope or other device comprising the two sights or
sight-points to be very easily and quickly removed from and replaced upon the gun..

page_text: The gun can, therefore, be dismounted without risk of injury to the sights. Moreover,
by the removal of the sights, the gun can be rapidly and effectually disabled cr
rendered useless to an enemy by whom it may be captured.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed I wish it understood
that I claim :-
First. A gun provided with sights or sight-points which are simultaneously
adjustable about an imaginary pivot or axis for the purpose above specified.
Second. The combination, with a curved sight-bar or segmental slide adjustable
about an imaginary pivot or axis, of a telescope or other device comprising two
sights or sight-points mounted upon the said curved bar or slide, for the purpose
above specified.
Third. An apparatus for aiming or directing a gun, wherein a telescope or other
device comprising two sights or sight-points is mounted on a curved slide adjustable
in a horizontal plane about an imaginary pivot or axis and carried by a curved
sight-bar which is adjustable in a vertical plane about an imaginary pivot or axis, for
the purposes above specified.
Fourth. In a sighting apparatus wherein two sights or sight-points are simultaneously
adjustable about an imaginary pivot or axis, the provision of suitable means for
effecting separate or independent lateral or horizontal adjustments of the said sights
or sight-points, for the purposes above specified.
Fifth. The combination, with the vertical curved sight-bar, of the horizontal
segmental slides and means for operating the same, substantially as, and for the
purposes, set forth.
Sixth. The improved apparatus constructed substantially as described with reference
to Figures 5, 6 and 7 of the accompanying drawings and operating as, and for the
purposes, above specified.
Dated this 18th day of June 1889.
th day of June 1889.
H. H. GRENFELL.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.