IMPROVEMENTS IN APPARATUS FOR SIGHTING ORDNANCE
Year: 1882

page_text: LETTERS PATENT to John Henry Johnson of 47 Lincoln's Inn Fields in the
County of Middlesex Gentleman for an invention of "IMPROVEMENTS IN
APPARATUS FOR SIGHTING ORDNANCE" communicated to him from abroad by
Albert Deport of Paris in the Republic of France
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 23rd May 1882.
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN APPARATUS FOR SIGHTING ORDNANCE a com-
munication to me from abroad by Albert Deport of Paris in the Republic of
France
:
This Invention relates to improvements in apparatus for pointing guns and it
has for its object enabling aim to be taken with speed and precision with proper
allowance for altitude range and windage. The said Invention is based on the
following principles vizt.
.:
At a given altitude the elements of pointing (angles of firing and windage) are
functions of the angle of inclination or depression of the butt. Consequently if a
piece of Ordnance is mechanically connected with a line of sight in such a manner
as to effect this mutual dependance of the elements of pointing and the angle of
inclination or depression it will suffice for the purpose of pointing the gun to move
it until the line of sight which automatically follows the movements of the gun
covers the object aimed at.
In carrying out this Invention the improved pointing or sighting apparatus is
composed firstly of a support rigidly attached to the trunnion of the gun Secondly
of an instrument provided with a telescope with cross hairs which is placed in
position for the operation of sighting being removed before firing and thirdly of a
stop fixed to the gun carriage.
The instrument is composed of two branches jointed with a hinge joint The
lower branch or base bears upon the support and partakes of all the movements of

page_text: the latter being secured in position by two upright pins or axes at right angles to
the support one of such pins being fixed and the other carried by a slider engaging
in recesses provided for its reception on the instrument The upper branch carrying
a spirit level bears upon an adjusting screw resting on the stop and serving to
adjust the level of the apparatus-The same branch also carries a telescope
provided with cross hairs--The Telescope is mounted on a T iron the stem of
which slides telescopically in the upper branch A groove is cut in this stem
corresponding with a similar groove formed on each side of the frame-A slider
provided with a horizontal axis may be fixed in the passage formed by these
grooves by means of a set screw The telescope is thus enabled to turn upon this
horizontal axis
At the other extremity of the T iron is jointed a sliding piece which is capable
of moving freely in a recess provided for its reception in the upright of the upper
branch This sliding piece rests by the intervention of a roller upon the edge of a
Cam of suitable shape mounted upon a horizontal axis marked by a crank and
connecting Link jointed to the lower branch-The edge of the Cam is provided
with webs or projections each of which corresponds to the use of a given class of
projectile and any one of these webs or projections may be brought into action as
required by shifting the Cam laterally on its axis.
A graduated scale is marked upon the side of the groove herein before referred to
and serves to indicate the position which the slider should occupy to correspond
with different altitudes
The deviation for windage is given automatically by means of a groove provided
for the purpose in the upper branch and in which works the fixed pin hereinbefore
described carried on the support.
This Groove is cut in a block mounted upon an axis and capable of a slight
lateral motion thereon which may be regulated by means of a scale for the purpose
of making the requisite allowance for windage
The apparatus works in the following manner viz-Two operators are required
to work the apparatus. The duty of the Assistant operator is to keep the level
horizontal by working the adjusting screw The other operator or sighter looks
through the Telescope and causes the gun to be moved laterally or to be raised or
lowered at the breech until the object aimed at is in line with the cross hairs.
When this has been accomplished the instrument is removed and the gun is ready
for firing.
The chief advantage of this apparatus is that it gives automatically all the
elements of sighting or pointing by simply taking a sight at the butt without
previously determining the distance. This method of pointing is eminently adapted
for firing at moveable objects and its employment enables the rapidity of firing to
be doubled and at the same time gives greater precision of aim-With this
apparatus the adjustment of the aim is easy quick and to a certain extent intuitive.
At an altitude of about eighteen yards it admits of firing with great precision.up
to about six thousand yards and thus greatly increases the efficiency of the Artillery
employed in the defence of hills.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Great Seal Patent Office on the
23rd November 1882.
"
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN
APPARATUS FOR SIGHTING ORDNANCE' a
communication to me from abroad by Albert Deport of Paris in the Republic of
France
This Invention relates to improvements in apparatus for pointing guns especially
adapted for guns used for Coast defences and it has for its object to enable aim to
be taken with speed and precision and with proper allowance for altitude range
and windage. The said Invention is based on the following principles videlicit
At a given altitude the elements of pointing (allowance for range and windage)
are functions of the angle of inclination and depression of the butt. Consequently
if a piece of ordnance (say for Coast defences) be mechanically connected with a
line of sight in such a manner as to effect this mutual dependence of the elements
of pointing and the angle of inclination or depression it will suffice for the purpose
of pointing the gun to move it until the line of sight which automatically follows
the movements of the gun covers the object aimed at.
Figure 1 is a longitudinal elevation of the apparatus placed upon the right
trunnion of a 24 ton gun 1870 Admiralty pattern.
Figure 2 is a plan of the support and base of the apparatus.
Figure 3 shows the projection of the cam of deviations and windage.
In carrying out this Invention the improved pointing or sighting apparatus is
composed firstly of a support C rigidly attached to the trunnion T of the gun
secondly of an instrument provided with a telescope L with cross hairs which is
placed in position for the operation of sighting and is removed before firing and
thirdly of a stop b fixed to the gun carriage
The instrument is composed of two branches jointed with a hinge joint. The
lower branch or base bears upon the support C and partakes of all the movements
of the latter being secured in position by two upright pins or axes at right angles
to the support one of such pins being fixed and the other carried by a slider
engaging in recesses provided for its reception on the instrument.
The upper
branch carrying a spirit level n bears upon an adjusting screw v resting on the
stop 6 and serving to adjust the level of the apparatus. The same branch also
carries a telescope L provided with cross hairs.
The telescope is mounted on a tee iron the stem of which slides telescopically
with slight friction in the upper branch. A groove is cut in this stem corresponding
with a similar groove formed on each side of the frame. A slider provided with
a horizontal axis may be fixed in the passage formed by these grooves by means
of a set screw. The telescope L is thus enabled to turn upon this horizontal axis.
At the other extremity of the tee iron is jointed a sliding piece which is capable
of moving freely in a recess provided for its reception in the upright of the upper
branch. This sliding piece rests by the intervention of a roller upon the edge of a
cam c of suitable shape mounted upon a horizontal axis worked by a crank m and
a connecting link d jointed to the lower branch. The edge of the cam c is pro-
vided with webs or projections each of which corresponds to the use of a given
class of projectile and any one of these webs or projections may be brought into
action as required by shifting the cam laterally on its axis.
A graduated scale is marked upon the side of the groove hereinbefore referred
to and serves to indicate the position which the slider should occupy to correspond
with different altitudes,

page_text: The deviation for windage is given automatically by means of a groove provided
for the purpose in the upper branch and in which works the fixed pin hereinbefore
described carried on the support. This groove is cut in a block mounted upon
an axis and capable of a slight lateral motion thereon which may be regulated
by means of a scale for the purpose of making the requisite allowance for
windage.
The apparatus works in the following manner videlicit. Two operators are
required to work the apparatus. The duty of the assistant operator is to keep
the level horizontal by working the adjusting screw v by means of a milled head r¹
on one end of the latter. The other operator or sighter looks through the telescope L
and causes the gun to be moved laterally or to be raised or lowered at the breech
until the object aimed at is in line with the cross hairs. When this has been
accomplished the instrument is removed and the gun is ready for firing.
"
The chief advantage of this apparatus is that it gives automatically all the
elements of sighting or pointing by simply taking a sight at the butt without
previously determining the distance. This method of pointing is eminently adapted
for firing at moveable objects and its employment enables the rapidity of firing to
be doubled and at the same time gives greater. precision of aim. With this
apparatus the adjustment of the aim is easy quick and to a certain extent intuitive.
At an altitude of about eighteen yards it admits of firing with great precision up
to about six thousand yards and thus greatly increases the efficiency of the artillery
employed in the defence of bills sea coasts or the like.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and
original and therefore claim as the Invention secured to me by the hereinbefore in
part recited Letters Pätent is.
The apparatus or instrument for sighting ordnance constructed or arranged
and combined substantially as herein before described with reference to the
accompanying drawings.
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal this twenty third day of November
One thousand eight hundred and eighty two.