CERTAIN IMPROVEMENTS IN THE HYDRAULIC BRAKES OF GUN CARRIAGES
Year: 1875

page_text: LETTERS PATENT to Alfred Longsdon, of Queen Victoria Strect, in
the City of London, Engineer, for the Invention of "CERTAIN
IMPROVEMENTS IN THE HYDRAULIC BRAKES OF GUN CARRIAGES."-A com-
munication from abroad by Alfred Krupp, of Essen, in the Kingdom
of Prussia, Cast Steel Manufacturer.
PROVISIONAL SPECIFICATION left by the said Alfred Longsdon at
the Office of the Commissioners of Patents, with his Petition,
on the 7th September 1875.
I, ALFRED, LONGSDON, of Queen Victoria Street, in the City of
London, Engineer, do hereby declare the nature of the said Invention
for "CERTAIN IMPROVEMENTS IN THE HYDRAULIC BRAKES OF GUN CARRIAGES,"
communication from Alfred Krupp, of Essen, in the Kingdom of
Prussia, Cast Steel Manufacturer, to be as follows :—
The object of this Invention is to so construct the hydraulic brakes
of gun carriages that a perfect control can be had at will over the sliding
of the gun, so that when desired the gun may be retained in any position

page_text: on the slide. This will be found of great service for naval guns, par-
ticularly in bad weather, and when from the rolling or pitching of the
vessel the gun is liable to break away from its lashings. During the
firing of the gun however this hydraulic brake is self-acting, and checks
the recoil of the gun in the ordinary manner. This-is-effected-by-means-
of a specially constructed piston fitted with a series of valves and packed
with leather. The piston rods pass through both covers of the hydraulic
cylinder. The hydraulic brake of the ordinary construction only checks
the recoil of the gun carriage in connection therewith, and is therefore
only applicable to guns used in land batteries or on level platforms.
For naval purposes where the level of the platform is always liable
to alteration through the motion of the sea, the hydraulic brake used
until now does not act as a clicck from the gun in its forward sliding
and offers no means of fixing the gun carriage in any position that may
be desired.
By means of this improved arrangement the gun carriage can be
fixed in any desired position by preventing the liquid in the hydraulic
cylinder from passing through the valves in the piston, these valves
always being kept closed by a spring, which spring can however be
operated upon by means of a lever, and then the valves are opened and
the liquid in the cylinder allowed to pass through the piston and the
gun carriage is able to move upon its slide.
In the ordinary hydraulic brake the cylinder is fixed and the piston
rod is attached to the gun carriage and moves with it, but in this
improved arrangement the cylinder is attached to the gun carriage and
traverses with it.
The piston is made in two pieces, and has in its centre a hollow
chamber or space. The piston rod does not pass through the piston,
but is formed in two parts, the forward part being fixed at one end to
the slide of the gun carriage, and the other end to the forward half of
the piston. The hinder piston rod is hollow, one end being attached to
the back portion of the piston and the other end to a bracket fixed to the
slide. In the forward half of the piston are placed two, three, four, or
more valve spaces, the valves themselves being carried on a disc, which
disc can slide to and fro in the chamber in the piston, and has screwed
or otherwise attached to it one end of a rod, which passes through the
hollow piston rod, and the other end of which rod presses against a

page_text: strong spring, the effect of which spring is always to press the disc in
the hollow of the chamber of the piston light against the forward half
of the piston, and thus bring the valves down upon their seats and pre-
vent the liquid in the cylinder passing through the piston.
There are holes formed through the disc, and corresponding with
similar holes in the hinder half of the piston, so that when the disc is
drawn back the liquid in the cylinder passes through the valves, which
are then open and then through the holes in the disc and hinder portion
of the piston, and so through into the back part of the cylinder; but in
order to open the valves in the piston it is necessary to draw back the
spring, and this is done by means of a screw lever.
When the gun is fired the great pressure that is then exerted upon
the valves in the piston over and above the pressure of the spring opens
the valves and allows the liquid to flow through the piston, but as soon
as this pressure becomes less than the pressure of the spring then the
valves immediately close and the gun carriage cannot move in either
direction until the valves are opened by pressing back the spring by
means of the screw lover. It will thus be seen that there is a perfect
control over the sliding of the gun carriage, and that even in a heavy
sea the gun can be held perfectly secure without using lashings.
Although I have described using two, three, four, or more valves in
the piston, still the piston may have only one valve placed in the centre
and communicating with inlet and outlet apertures in the front land
back piston rods. The piston is also formed of two halves fastened
together by bolts. The valve is connected to the rod passing through
the hollow piston rod, and is acted upon by the spring, exactly as in the
construction of piston with two or more valves and just before described.
0
SPECIFICATION in pursuance of the conditions of the Letters Patent,.
filed by the said Alfred Longsdon in the Great Seal Patent Office.
on the 31st January 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
LONGSDON, of Queen Victoria Street, in the City of London, Engineer,
communication to him from abroad by Alfred Krupp, of Essen, in the
Kingdom of Prussia, Cast Steel Manufacturer, send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventh day of September, in the
year of our Lord One thousand eight hundred and seventy-five,
in the thirty-ninth year of Her reign, did for Herself, Her heirs and
_successors,_give_and_grant_unto_me,_the_said Alfred Longsdon, Her
special licence, that I, the said Alfred Longsdon, my executors,
administrators, and assigns, or such others as I, the said Alfred
Longsdon, my executors, administrators, and assigns, should at any.
time agree with, and no others, from time to time and at all times
. thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "CERTAIN IMPROVEMENTS IN THE HYDRAULIC BRAKES OF GUN
CARRIAGES," upon the condition (amongst others) that I, the said Alfred
Longsdon, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Alfred Longsdon, do hereby
declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and. by the following statement :-
The object of this Invention is to so construct the hydraulic brakes
of gun carriages that a perfect control can be had at will over the sliding
of the gun, so that when desired the gun may be retained in any position
on the slide. This will be found of great service for naval guns, par-
ticularly in bad weather, and when from the rolling or pitching of the
vessel the gun is liable to break away from its lashings. During the
firing of the gun however this hydraulic brake is self acting and checks
the recoil of the gun in the ordinary manner. This is effected by means
of-a-specially constructed piston fitted-with-a-series-of-valves-and-packed
with leather, the piston rods pass through both covers of the hydraulic
cylinder. The hydraulic brake of the ordinary construction only checks
the recoil of the gun carriage in connection therewith, and is therefore
only applicable to guns used in land batteries or on level platforms.

page_text: For naval purposes where the level of the platform is always liable to
alteration through the motion of the sea the hydraulic brake heretofore
used does not act as a check upon the gun in its forward sliding and
offers no means of fixing the gun carriage in any position that may be
desired.
By means of this improved arrangement the gun carriage can bo
fixed in any desired position by preventing the liquid in the bydraulic
cylinder from 'passing through the valves in the piston, these valves
always being kept closed by a spring, which spring can however be
operated upon by means of a lever, and thus the valves be opened and
the liquid in the cylinder allowed to pass through the piston, the gun
carriage is then able to move upon its slide.
In the ordinary hydraulic brake the cylinder is fixed and the piston
rod is attached to the gun carriage and moves with it, but in this
improved arrangement the cylinder is attached to the gun carriage and
traverses with it.
In the Drawings hereunto annexed is shown the method in which
this Invention is carried into effect, the hydraulic brake being
represented as applied to a naval gun carriage.
Figure 1, Sheet 1, is a side elovation, partly in section; and Figure 2, .
a plan of this improved construction of brake.
Figure 3, Sheet II., is a section through the hydraulic cylinder;
Figure 4 is an enlarged section of the piston taken through the lines
x, y, z, of Figure 5, which is an end view of the piston; Figure 6 is
a view of the piston, one half of which is removed in order to show the
valves in the other half.
The same letters of reference indicate similar parts in cach of the
Figures.
In this arrangement the piston is shewn fitted with four valves;
A is the cylinder fitted with a cover C, having formed upon it two
strong pins a, a; G, G, are two connecting rods attached at one end to
the pins a, a, the other ends being formed into forks, which embrace,
and are attached by strong bolts to brackets b rivetted firmly to the
under side of the gun carriage H. By this means the cylinder is
5 attached to the gun carriage and moves with it. The other or back end
of the cylinder is furnished with a wrought-iron flange c, to which the

page_text: cylinder cover D is attached by bolts and nuts; B is the piston, which
forms the essential part of this Invention.
This piston B is formed in two halves d and e, which are fitted into
each other with lap joints, as shewn, and then firmly secured by the
bolts and nuts f. E and F are two piston rods, the rod E being screwed
into the half d of the piston, and the rod F to the other half e. Both
piston rods pass through stuffing boxes in the covers of the cylinder.
The cylinder is always full of the ordinary fluid without reference to the
position of the piston; and the two piston rods have the same dimensions,
so that their displacement of the fluid in the cylinder is equal on each
side of the piston. The two halves of the piston are turned out on the
inside so as to form a cylindrical space in the combined piston, as
shewn. h, h, are four valve spaces formed in the forward half of the
piston; is a metal disc which is capable of moving to and fro in the
space in the piston, and has fitted to it four valves corresponding in
position to the valve spaces in the half piston d; k, k, are four holes
drilled through the disc i and corresponding with four holes drilled
through the back half e of the piston, so that when the valves h, h, are
open the fluid in the cylinder can freely pass through the piston;
m, m, are leather packings to the piston to prevent the liquid in the
cylinder passing at any time between the circumference of the piston
and the cylinder.
The forward piston rod E is fixed to the front end of the slide by
means of a cross head n and bolt o passing through the iron frames
forming part of the slide, while the hinder rod F is attached to the a
bracket P, and is thus secured against any lateral movement. This
hinder rod F is hollow, as shewn in the Drawings, and through it is
passed a rod q, one end of which is screwed into the disc i which carries
the valves, while the other end is connected with a strong spring $ by
means of the coupling 1. This spring S presses upon the rod 7 and 3
forces it forward, and thus brings the valves on the disc i down upon
their seats and closes them. t is a screw lever, the action of which
when it is raised up is to depress the spring and draw back the disc i
and open the valves in the forward half of the piston and allow free
passage of the liquid in the cylinder through the piston. The valves in g
the piston are closed by depressing the lover, and then the spring forces
the rod a forward, and with it the disc i, bringing the valves down upon
their seats.

page_text: The action of this breake is as follows:-Presuming the breake to be
n the position shewn in Figures 1 and 2, Sheet 1, the gun would then be
orward ready for firing. The liquid in the cylinder would be in front
of the piston. Directly. the gun is discharged the recoil of the carriage
commences and then the pressure on the liquid in the cylinder will be
very great and far beyond the pressure of the spring S, which will there-
fore be forced back by the pressure of the liquid against the valves which
will consequently be opened, and the liquid in the cylinder will pass
through the piston, as in the ordinary brake, and this passage of the
liquid will continue until the pressure due to the recoil falls below the
pressure of the spring S, and then the spring will come into action, and
forcing forward the rod q will bring the valves on the disc i down upon
their seats, and all further passage of the liquid will be stopped. It will
be thus seen that until the valves are opened by raising the levert the
capability of the gun to move in either direction is quite prevented, and
therefore the gun cannot be run forward until the lever is raised and the
valves are opened. This arrangement therefore admits of perfect control
over the action of the gun; and for naval purposes this brake will be
found of great advantage, as while the lever is down and the valves
closed the passage of the fluid is impossible through the piston, and
therefore in the heaviest sea there could be no danger of the gun
breaking loose even if no lashings were used to fasten the gun.
For greater security at sea and when the guns are not required for
use a block or stop may be placed so as to prevent any possibility of,
depressing the spring S, but care must be taken to remove this block or
stop before firing the gun.
The brake just described is shewn with four valves, but the Invention
is not confined to this number, as more or fewer may be applied with
equal facility; and in Figures 7, 8, 9, Sheet III., is shewn a piston
fitted with only one valve. The piston is made in two halves firmly
attached together by the bolts f,f. The front and back piston rods are
shewn in one piece with their respective portions of the piston. The
back piston rod is also hollow, and through it is passed the rod q
having attached to its front end the valve h. K, K, are holes drilled
5 through the neck of the piston rod E, and communicating with the
valve h; and 1, l, are holes through the boss of the piston rod F. The
rod Պ is attached to a spring exactly in the same way as described in
reference to the brake with four valves, and shown in Sheets I. and II.,

page_text: and the action of this arrangement is precisely similar. When the
recoil takes place the pressure forces back the spring, and thus opening
the valve the fluid can flow in through the holes K, K, and passing
through the valve escapes through the holes 1, 2, into the back part of
_the_cylinder. When_the_gun_is_to-be-run-forward-the-spring-is-
depressed which opens the valve h, and the flow of the liquid is thus
reversed, videlicet, it enters through the holes 1, 2, and passing through
the valve / escapes through the holes K, K. In all other respects the
brake is the same, and is attached to the gun carriage in a similar
manner, as before described.
And having now. described the nature of this Invention as communi-
cated to me, and the manner of putting the same into practical operation,
I declare that I claim, forming the piston in hydraulic brakes of gun
carriages in two parts and fitted with piston rods, valves, disc, and other
accessories, whereby a perfect control is obtained over tho traverse of
the gun carriage upon its slide, all constructed and operating sub-
tantially in the manner described.
In witness whereof, I, the said Alfred Longsdon, have hereunto
set my hand and seal, this
in the
day of
of In Low! One thousand night lundred and seventy