Improvements in Sighting Apparatus for Guns.
Year: 1891

page_text: Die of Application, 13th Apr., 1851
Complete Specification Left, 13th Jan., 1892-Accepted, 13th Feb., 1892
PROVISIONAL SPECIFICATION.
Improvements in Sighting Apparatus for Guns.
1, JAMES HORNE, of 2 Victoria Mansions in the City of Westminster, Engineer,
do hereby declare the nature of this invention to be as follows :-
:―
My invention relates to automatic sighting apparatus for turret and other guns.
My improvements are intended to be applied to that kind or class of sighting
apparatus where the sights are not upon the gun but are carried by sight bars one
of which is stationary and the other of which moves with the gun.
When the gun is used for high angle fire the system of automatic sights
heretofore employed necessitates a very large vertical movement of the rear
sight bar, and unduly long lengthening pieces on the fore and rear sights.
Moreover in this system the rear sight bar does not have imparted to it such
movement as to cause the angular motion of the line of sight to correspond
accurately with that of the gun, and at high angles of elevation the error from
this cause is very appreciable.
According to one part of my invention I obvinte the necessity of employing
lengthening pieces for the sights, and avoid the great inconvenience caused to
the gunner by reason of his having to be continually changing his position to
adapt himself to the vertical movement of the sight bar as follows, that is to say,
make the rear sight bar stationary and the fore sight bar movable with the
gun. I connect the said fore sight bar to the gun in such a manner that the
relative angular movement of the sights will truly coincide with the angular
movement of the gun. I arrange the tangent bar on the rear sight bar as
heretofore but in my improved apparatus the said tangent bar has a vertical
movement corresponding to the changes required for varring the range only and
the movement being comparatively small no inconvenience is caused to the
gunner in laying the gun. The fore sight bar is carried in such a manner that
it can work through the roof of the shield or turret, and it is geared to the
gun by suitable mechanism which will communicate to it the required movement
for accurately laying the gun to any desired elevation.
According to another part of my invention I provide the mechanism or
gearing which connects the gun and fore-sight bar with a compensating apparatus
that operates to correct the error due to the difference between the tangential
One form of
motion of the sight bar and the circular motion of the gun.
compensating apparatus which I sometimes employ comprises a sleeve mounted
so as to be capable of sliding endwise on a shaft while being compelled by a
feather key or equivalent means to rotate with the shaft. The said shaft is
connected by suitable mechanism with the gun and is rotated thereby when the
worin
I provide on the sleeve a
gun moves about its trunnions.
or spiral
groove and arrange the same to work in a stationary nut so that when the
sleeve is rotated it is caused by the said nut and worm or spiral groove to
I also
have an end wise sliding motion in one or other direction on the shafi.
form in the said sleeve one or more cam-like grooves for the purpose herein-
after described. The fore sight bar is connected by suitable gearing with a
pinion mounted on the aforesaid sleeve. I do not however rigidly key the
pinion to the sleeve but mount it loosely thereon and provide the pinion
with one or more pins that project into the aforesaid cam-shaped groove or
grooves which pins operate to drive the pinion when the sleeve is rotatel.
while allowing of the sleeve sliding through the pinion. Suitable bearings or
stops are provided to prevent end wise movement of the pinion.

page_text: By the above described arrangement the pinion is caused to rotate faster than
the sleeve, the increment of speed depending upon the form of the groove or grooves
and the pitch of the spiral groove or worm in the sleeve, these being so arranged as
to give such movement to the sight bar as to cause the line of sight to have an
angular movement corresponding exactly with that of the gun.
Another form of compensating gear that I may use comprises a cam shaped
toothed wheel mounted on the driving shaft and gearing with a rack on the sight
bar, the said rack being suitably shaped to gear with the cam wheel. The shape
of the said cam wheel is arranged to give the desired true motion to the sight bar.
Although I have only described my compensating device as applied to the fore
sight bar of my improved arrangement of automatic sights where the fore sight bar
is movable, it is obvious that I may if desired apply it also to compensate the error
in the movements of the rear sight bar of automatic sights as heretofore constructed.
Dated this 13th day of April 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant,
COMPLETE SPECIFICATION.
Improvements in Sighting Apparatus for Guns.
I JAMES HORNE of 2 Victoria Mansions, in the City of Westminster, Engineer,
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 automatic sighting apparatus for turret and other guns.
My improvements are intended to be applied to that kind or class of sighting
apparatus where the sights are not upon the gun but are carried by sight-bars one
of which is stationary and the other of which moves with the gun. Heretofore the
rear sight bar has been the one that moves.
When the gun is used for high-angle fire the system of automatic sights heretofore
usually employed necessitates a very great range of travel of the rear sight-bar,
and unduly long lengthening pieces on the fore and rear sights and causes much
inconvenience to the gunner. Moreover in this system the angular movement of
the line of sight does not correspond accurately with that of the gun, and at high
angles of elevation the error or deviation from the true movement is very appreciable
and prevents accurate aim.
According to one part of my invention I obvinte the necessity of employing
lengthening pieces for the sights, and I avoid the inconvenience caused to the
gunner by reason of his having to be continually changing his position to adapt
himself to the vertical movement of the sight-bar. For this purpose I make the
rear sight-bar stationary and the fore sight-bar movable with the gun.
I arrange
the tangent bar on the rear sight-bar as heretofore but in my improved apparatus
the said tangent-bar has only such vertical movements as are required for varying the
range, and these movements being comparatively small no inconvenience is thereby
caused to the gunner in laying the gun. The fore sight-bar is carried in such a
manner that it can work rectilineaily through the roof of the shield or turret, and
it is geared to the gum by suitable mechanisin which will communicate to it the
required movement for accurately laying the gun to any desired elevation.
According to another part of my invention I connect the said fore sight-bar to
the gun in such a manner that the relative angular movement of the sights will
truly coincide with the angular movement of the gun. For this purpose I provide
the mechanism or gearing which connects the gun or the slide and fore sight-bar
with a compensating apparatus which in the conversion of the circular movement of
the gun or slide into the rectilinear movement of the sight-bar operates the movable
sight-bar in such a manner as to compensate for the difference between tangential
and circular movement of the fore sight relatively to the rear sight.

page_text: TO LAC ACCcompany
pair of guns mounted in a turret.
Figure 1 is a side elevation, and
Have SHOW MY Vention app
Figure 2 is a plan of a gun and fore and rear sights arranged and actuated
according to my invention, the said figures showing also the connecting gear of the
said sights with the gun.
Figure 3 is a longitudinal section on a larger scale through a portion of the gear
hereinafter described.
Figure 4 is a development drawn to a still larger scale of the sleeve illustrated in
Figure 3 and clearly showing the shape of the cam grooves, hereinafter described.
and
Figure 5 is an elevation of a modification of my invention showing a cain shaped
pinion and a rack designed to gear therewith.
Like letters of reference indicate corresponding parts throughout the drawings.
A is the gun, B, B are its trunnions carried by the recoil brake cylinders C, C,
which are mounted to recoil on the slides D, D. a is the rear sight, and is
the fore sight. The rear sight a is mounted on an ordinary tangent bar a
which is capable of being moved vertically on a fixed bar a' the latter bar
being secured in any suitable manner to the gun mounting. The said tangent
bar is provided with a deflection leaf as is usual in such sights. The fore
sight is mounted on a bar which is guided in suitable bearing brackets_c.
To the lower end of the bar is fixed a rack that is geared with the
elevating mechanism so that when the gun is turned about its trunnions to effect
the vertical pointing of the same the said bar is moved vertically and maintains
the line of sight in true relation to the axis of the gun. Any suitable gearing
may be employed for turning the gun about its trunnions. The arrangement
shown in the drawing comprises an are E fixed on the gun and gearing with a
pinion Figure 2 carried by a short transverse shaft supported in a bearing G.
This shaft is geared by bevel wheels H, I, with a square shaft carried by
bearings and arranged exactly parallel with one of the recoil slides D. A
wheel is carried by a bearing K supported by a bracket I. fixed to one of
the slides D; the said wheel is free to revolve in its bearing and is mounted
upon the square shaft J or otherwise arranged so that the shaft is free to slide
through the wheel when the gun recoils and runs out, but the shaft and wheel
are compelled to revolve together. The wheel K gears with another wheel M
fixed on a short shaft N supported by bearings N' fixed on the said bracket L.
On the shaft N in frictional gear therewith is a worm wheel which through a
worm shaft Q, bevel gears R and shaft S, is connected with one of the
hand wheels T used by the gunner when effecting the vertical pointing of the
gun. The above described gearing forms no part of the present invention except
as used in combination with other parts now to be described.
On the shaft N is mounted a sleeve d Figure 3 that is connected therewith by a
feather key so as to be compelled to rotate with the shaft while being free to slide
longitudinally thereon. The said sleeve is screw threaded externally at one end as
shown at and works in a stationary nute which is carried by the bracket L.
In the said sleeve is or are formed one or more spiral shaped grooves clearly
shown in the development in Figure 4. Upon the sleeved is placed another sleeve/
which is supported in one of the bearings and is free to rotate in the said bearing
but is prevented from endwise movement therein by suitable stops as for instance
by collars provided on the said sleeve. The sleeves and are compled together
by means of pins screwed or otherwise removably fixed in the latter and projecting
into the aforesaid spiral grooves in the former, one such pin being provided for each
spiral groove.
A toothed pinong is formed with or fixed on the sleeve and gears
with the rack on the fore sight-bar .
The mode of operation of this mechanism is as follows:-When the gunner
rotates the said hand wheel T to turn the gun about its trunnions the motion of
the shaft N is communicated through its feather key to the sleeve d, and this

page_text: sleeve drives the outer sleeve through the driving pins thereby operating
to raise or lower the fore sight-bar according to the direction in which the
gun is moving. Sinee however the sleeve d is screw-threaded and works in a
fixed nut it is obvious that the said sleeve when rotated with the shaft N is
by reason of its screwed part caused to slide longitudinally on the said shaft
and through the sleeve, that is to say, the said sleeve d has both a rotary and
a sliding movement imparted to it when the shaft N is rotated. It is further
obvious in consequence of the pin and spiral groove connection between the two
sleeves d, f, that a sliding movement of the sleeve d will cause a partial rotation
of the outer sleeve and by forming the grooves in the proper direction a
rotative movement of the outer sleeve due to the sliding movement of the
sleeve may be added to that caused by the rotation of the said sleeve d, or
in other words the sleeve is by this mechanism driven faster than the sleeve d.
The inclination of the spiral grooves is so arranged in relation to the pitch
of the screw threads that the increment of speed thereby given to the sight
bar in all positions is such as to cause the line of sihgt to have an angular
movement corresponding accurately with that of the gun.
In a modification of my compensating gear I dispense with the aforementioned
sleeves and employ instead thereof a cam shaped toothed wheel Figure 5 fixed
on the shaft N and gearing with a correspondingly shaped rack formed on the
fore sight bar 6. The shape of the rack is so designed that such movement of
the fore sight bar is obtained which ensures the line of sights moving accurately
with the gun at every angle of elevation.
In cases where a gun is mounted on a pivoted beam or slide
sight bar with the said beam or slide instead of with the gun.
provision is necessary to prevent disconnection of the gearing by
of the gun.
gear the movable
In such a case no
reason of the recoil
Although I have only described my compensating device as applied to the fore
sight bar of any improved arrangement of automatic sights where the fore sight bar
is movable it is obvious that I may if desired apply it also to compensate the error
in the movements of the rear sight bar of automatic sights as heretofore con-
structed.
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 do not claim generally or apart from the provision for ensuring true angular
movement the combination in automatic sighting apparatus of a rear sight or sighting
point which is automatically moved by or with the gun and a fore sight which is
unconnected with the gun as without such provision the apparatus would not serve
the purpose of my invention. Morcover I am aware that in the Specification of a
former Patent wherein there is described a fixed fore sight and an automatically
movable rear sight reference is made to true angular movement as the object
attained but inasmuch as in the apparatus described in the said Specification no
provision is made to compensate for the difference between circular and tangential
movement of one sight relatively to the other it is obvious that with such apparatus
true angular movement could not be obtained at high angles, but I claim:
First. For automatic sighting the combination, with a gun, of a fixed sight-bar
and a rectilinearly movable sight-bar arranged and operating in such a manner that
the angular movement of the line of sight between the two sighting points is true
with that of the gun.
Second. A gun provided with automatic sighting apparatus of which the fore-
sight bar is geared with and moved rectilinearly by or with the gun or slide in
combination with a fixed or stationary rear sight-bar substantially as and for the
purpose set forth.
Third. In automatic sighting apparatus a fore sight which is rectilinearly
movable with the gun arranged in combination with an adjustable tangent sight on
a fixed rear sight-bar substantially as and for the purpose specified,

page_text: Fourth. In apparatus for the conversion of circular into rectilinear movement the
combination of a part having a spiral groove or grooves with a part provided with
pins or studs projecting into the said groove or grooves the two parts operating to
compensate for the difference between circular and tangential movement of one
point relatively to another point as above set forth.
Fifth. The compensating apparatus constructed substantially as described with
reference to Figures 3 and 4 of the drawings and arranged to operate in com-
bination with the automatically movable sight-bar for the purpose specified.
Sixth. The modification of the compensating apparatus substantially as described
with reference to Figure 5 of the drawings.
Seventh. The combination of my improved automatic sighting apparatus with a
gun or guns in a turret or barbette substantially as described for the purpose
specified.
Dated this 12th dox of Lanu 1800
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.