IMPROVEMENTS IN APPARATUS FOR SIGNALLING PURPOSES
Year: 1880

page_text: LETTERS PATENT to Mark Charles Denne, of 1, Christchurch Road, Eastbourne,
"
in the County of Sussex, and Thomas James Denne, of Holmesdale Lodge,
Red Hill, in the County of Surrey, for an Invention of IMPROVEMENTS IN
APPARATUS FOR SIGNALLING PURPOSES."
PROVISIONAL SPÉCIFICATION left by the said Mark Charles Denne and
Thomas James Denne at the Office of the Commissioners of Patents on the
19th November 1880.
MARK CHARLES DENNE, of 1, Christchurch Road, Eastbourne, in the County of
Sussex, and THOMAS JAMES DENNE, of Holmesdale Lodge, Red Hill, in the County
of Surrey. "IMPROVEMENTS IN APPARATUS FOR SIGNALLING PURPOSES."
Our improvements consist in placing alongside the line of rails at convenient
distance apparatus consisting of two cylinders arranged side by side, each open at
one end; pistons fitted to these cylinders travel or move backwards and forwards,
each having three distinct motions of a certain length. At the closed ends of the
cylinders each have a pipe fitted communicating with the inside; these pipes are carried
from the apparatus to the signal box wherever placed, and attached to an appliance
which we call a disc valve. A pipe is fixed to the middle of each cylinder at the
side or most convenient place cominunicating with the inside; these pipes are also
carried to the signal box, and are connected with an appliance acting as an indicator
or telltale, which, for convenience, we purpose calling an indicator; upon the top
of and also in the middle of each cylinder is placed a whistle, constructed on the
same principle as those used on locomotives, or any appliance which will produce
sound by the action of compressed air; these whistles also communicate with the
inside of the cylinders. The pistons working in the cylinders are recessed or
nicked out in the middle of their length; both ends of the piston are hollow,
leaving a solid portion in the middle, to which is attached the ends of connecting
rods, the other ends of the rods being fitted to levers working on a rocking shaft

page_text: or stud, as may be most convenient. These levers are connected to other levers by
rods, the levers working on rocking shaft; on these shafts are also short levers
connected to bridge pieces at one end; the other ends of the bridge pieces are
carried by short levers to keep them parallel while in motion up and down.
Connected with the whistles are pipes, one to each, with check valves placed in
them to prevent a return current or pressure of air when the communication is
made between the cylinders and whistles.
The front of the disc valves are made with three openings, one communicating
with each of the cylinders by means of the pipes before mentioned, the other
acting as an exhaust pipe. The disc is made with a slot of a certain length at an
equal distance from the centre, sufficiently long to open communication with the
two pipes from the cylinders and a pipe at the back of the valve, the said pipe
being connected with a vessel charged with compressed air of sufficient density to
produce the results required. In the disc of the valve is also a recess sufficiently
long to cover the openings of all three pipes when desired; the disc is worked by
a handle fixed to it by means of a short shaft passing through the .front of the
valve; the disc is free to revolve between the front and back of the valve, yet
perfectly tight to prevent the escape of the compressed air.
From the inside ends of the pistons holes are made as a means of communication
between the recess and the interior of the cylinders, and by that means the pistons
are in the right position to make the communication between the compressed air
in the cylinders and the whistle. The pipes attached to the sides of the cylinders
are also made to receive a portion of the compressed air from the same motion of
the pistons, and allow a current being sent along the pipe to the indicator in the
signal box, thereby telling the position of the train on the line.
By a movement of the disc in the valve communication is made between the
store of compressed air and one or both of the pipe leading to the cylinders; if of
one only, the other is by means of the recess made to communicate with the
exhaust pipe. By the relative positions of the slot and recess in the disc, and also
the openings to the two pipes leading to the cylinders, and also the exhaust pipe, a
means of signalling is established between the signalınan in the box and the driver
of the train by means of the whistles fixed to the apparatus alongside the line.
The depression of one or both of the bridge picces by a roller fixed to the engine
causes the piston to return to the middle of the cylinders, having previously been
sent to the extreme length of their stroke by the pressure of air; the return to the
middle opens communication, as before described.
The pipes direct to the whistles, with the check valves in them, are carried to
the signal box to enable the signalman to communicate with the driver of the train
independently of the other signals, so that he may notify to the driver what to do
either before or after the train has passed over the bridge pieces connected with
the apparatus.
The return current of air to the indicator strikes a disc placed over the opening
of the pipe in the sigual box, which causes the hammer of the indicator to fall
upon a bell, and also a pendulum to vibrate if necessary.
These apparatus can be placed in an iron box with a lid on the top; this lid is
raised by the compressed air forcing the piston to its extreme length of stroke,
acting on the lever connected to it by the rod; this lever in passing strikes a
tappet, and by means of rocking shaft, lever, and links, the lid is raised to allow
the sound of the whistle to escape; the lid is kept in position by a balance weight,
which is thrown over the centre by the same motion that is used to raise it. The
lid remains open so long as the apparatus is in use, but when the pressure of air is
taken off a counter balance placed on the rocking shaft connected with the bridge
piece forces the piston back to the bottom of the cylinder, thereby giving a reverse
motion to the tappet, throwing the balance over the centre on the other side, and
causes the lid to close.
We purpose actuating this system of signalling (by means of compressed air

page_text: accumulated and closed in a convenient place, and in quantities and pressure) to
produce the result of giving motion to the pistons, blowing the whistle, communi-
cating direct by means of the third pipe with the driver of the train, and sending
a return current back to the signal box after the train has passed over the bridge
pieces.
The apparatus is described with reference to railway signalling, but it is
applicable to ships and signalling purposes generally.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Mark Charles Denne and Thomas James Denne in the Great Seal
Patent Office on the 19th May 1881.
MARK CHARLES DENNE, of 1, Christchurch Road, Eastbourne, in the County of
Sussex, and THOMAS JAMES DENNE, of Holmesdale Lodge, Red Hill, in the County
of Surrey. *IMPROVEMENTS IN APPARATUS FOR SIGNALLING PURPOSES."
Our improvement consists in placing alongside the line of rails at convenient
distances apparatus consisting of two cylinders arranged side by side, each open at
one end; pistons fitted to these cylinders travel or move backwards and forwards,
each having three distinct motions of a certain length. At the closed ends of the
cylinders each have a pipe fitted communicating with the inside; these pipes are
carried from the apparatus to the signal box wherever placed, and attached to an
appliance which we call a disc valve. A pipe is fixed to the middle of each
cylinder at the side or most convenient place communicating with the inside; these
pipes are also carried to the signal box, and are connected with an appliance acting
as an indicator or telltale, which for convenience we purpose calling an indicator;
upon the top of and also the middle of each cylinder is placed a whistle, constructed
on the same principle as those used on locomotives, or any appliance which will
produce sound by the action of compressed air; these whistles also communicate
with the inside of the cylinders. The pistons working in the cylinders are recessed
or nicked out in the middle of their length; both ends of the pistons are hollow,
leaving a solid portion in the middle to which is attached the ends of connecting
rods, the other ends of the rods being fitted to levers on a rocking shaft or stud, as
may be most convenient. These levers are connected to other levers by rods, the
levers working on rocking shafts. On these shafts are also short levers connected
to bridge pieces at one end; the other ends of the bridge pieces are carried by short
levers to keep them parallel while in motion up and down.
Connected with the whistles are pipes, one to each, with check valves placed in
them to prevent a return current or pressure of air when the communication is made
between the cylinders and whistles.
The front of the disc valve has three openings, one communicating with each
of the cylinders by means of the pipes before mentioned, the other acting as an
exhaust pipe.

page_text: The disc is made with a slot of a certain length at an equal distance from the
centre sufficiently long to open communication with the two pipes from the
cylinders, and with a pipe at the back of the valve, the said pipe being connected
with a vessel charged with compressed air of sufficient density to produce the result
required. In the disc of the valve is also a recess sufficiently long to cover the
openings of all three pipes when desired; the disc is worked by a handle fixed to
it by means of a short shaft passing through the front of the valve; the disc is free
to revolve between the front and back of the valve, yet perfectly tight to prevent
the escape of compressed air.
From the inside ends of the pistons holes are made as a means of communication
between the recess and the interior of the cylinders, and by that means when the
pistons are in the right position, communication is made between the compressed
air in the cylinders and the whistles. The pipes attached to the sides of the
cylinders are also made to receive a portion of the compressed air from the same
motion of the pistons, and allow a current being sent along the pipe to the indicator
in the signal box, thereby telling the position of, say, a train on the line.
By a movement of the disc in the valve communication is made between a storo
of compressed air and one or both of the pipes leading to the cylinders; if of one
only, the other is by means of the recess made to communicate with the exhaust
pipe.
By the relative position of the slot and recess in the disc, and also the openings
to the two pipes leading to the cylinders, and also the exhaust pipe, a means of
signalling can be established between the signalman in the box and the driver
of the train by means of the whistles fixed to the apparatus alongside the line.
The depression of one or both of the bridge pieces by a roller fixed to the engine
causes the pistons to return to the middle of the cylinders, having previously been
sent to the extreme length of their stroke by the pressure of air; the return to the
middle opens communication as before described.
The pipes direct to the whistles with the check valves in them are carried to the
signal box to enable the signalman to communicate with the driver of the train
independently of the other signals, so that he may notify to the driver what to do
either before or after the train has passed over the bridge pieces which are connected
with the apparatus. The return current of air to the indicator strikes a disc placed
over the opening of the pipe in the signal box, which causes the hammer of the
indicator to fall on a bell, and also a pendulum to vibrate if necessary.
These apparatus can be placed in an iron box with a lid on the top; this lid is
raised by the compressed air forcing the piston to its extreme length of stroke,
acting on the lever connected to it by the rod; this lever in passing strikes a tappet,
and by means of rocking shaft, lever, and links, the lid is raised to allow the sound
of the whistle to escape. The lid is kept in position by a balance weight, which is
thrown over the centre by the same motion that is used to raise it; the lid remains
open so long as the apparatus is in use, but when the pressure of air is taken off,
a counter balance placed on the rocking shaft connected with the bridge piece
forces the piston back to the bottom of the cylinder, thereby giving a reverse
motion to the tappet for throwing the balance over the centre on the other side,
and causes the lid to close.
We purpose actuating this system of signalling (by means of compressed air
accumulated and stored in a convenient place and in quantities and pressure) to
produce the result of giving motion to the pistons, blowing the whistle, commu-
nicating direct by means of the third pipe with the driver of the train, and sending
a return current back to the signal box after the train has passed over the bridge
pieces.
The apparatus is described with reference to railway signalling, but it is
applicable to ships and signalling purposes generally.
Our Invention will be clearly understood by reference to the annexed

page_text: By means of the openings in the disc valve compressed air is allowed to enter
the cylinders by means of pipes from store, which will force the piston out to its
extreme length of stroke, as shown, Figure 4, Sheet 2, at the same time raising the
bridge piece, so that the roller k in passing forces it down to the position shown at
Figure 3, Sheet 2, thereby allowing the air to flow through the passages b, Figure 5,

page_text: Sheet 2, into the neck a, Figure 5, Sheet 2, and the whistle B, Figure 2, Sheet 1,
and also into return pipe l, Figures 1, 2, and 3, Sheet 1, by means of a hole in line
with said pipe inside of cylinders.
The whistle is sounded by means of the compressed air allowed to pass into it
by the depression of the bridge piece (fixed alongside the rails) by means of the
roller on the engine of the passing train, thereby giving the driver instructions
what to do, either to go on or stop, according to prearranged plan; one or both of
the bridge picces can be raised by the signalman, and corresponding signals will
be given by means of the whistles.
The return current of air through the pipes L, Sheet 1, striking against the
disc a, Figures 6, 7, and 8, Sheet 3, causes it to rise, thereby carrying the hammer d
over the centre, which in falling strikes the bell B, at the same time causes the
pendulum to vibrate, and by that means the position of the train is shown.
By means of the disc valve, Figures 1 to 5, Sheet 3, the signalman has the power
of opening communication between the store of compressed air and one or both of
the cylinders; Figure 3, Sheet 3, shows that communication between the cylinders
and the store of air is cut off, and both pipes a and b. are connected with c, the
exhaust; Figure 4 shows a, communicating with D, Figure 2, the main, and also b
connected with c by means of the recess; Figure 5 shows both a and b commu-
nicating with the store of compressed air by means of D, Figure 2, Sheet 3, and
the connection cut off between the exhaust c and the two other pipes.
Having now described the nature of our said Invention, and in what manner
the same is to be performed, we declare that we claim as our Invention,
The arrangement of appliances, as herein described, for the purpose of sound
signalling on railways, ships, and other vehicles and places.
Secondly. The compensation piston shown in detail in Sheet 2, Figures 2, 3, 4,
and 5 of the annexed Drawings, said piston being actuated by compressed air on
one side and by the weight of the bridge piece on the other for the purposes set
forth.
In witness whereof, we, the said Mark Charles Denne and Thomas James Denne,
have hereunto set our hands and seals, this Eighteenth day of May, in
the year of our Lord One thousand eight hundred and eighty one.