IMPROVEMENTS IN MACHINERY OR APPARATUS FOR SIGNALLING
Year: 1875

page_text: LETTERS PATENT to Edward Griffith Brower, of Ohancery Lane,
London, for the Invention of "IMPROVEMENTS IN MACHINERY OR
APPARATUS FOR SIGNALLING."—A communication from abroad by Isidor
Selten, of Vienna, Austria.
Sealed the 18th January 1876, and dated the 19th July 1875.
PROVISIONAL SPECIFICATION left by the said Edward Griffith
Brewer at the Office of the Commissioners of Patents, with his
Petition, on the 19th July 1875.
I, EDWARD GRIFFITH BREWER, of Chancery Lane, London, do
hereby declare the nature of the said Invention for "IMPROVEMENTS
IN MACHINERY OR APPARATUS FOR SIGNALLING," (a communication to me
from abroad by Isidor Selten, of Vienna, Austria,) to be as follows.―
The object of this Invention is to construct a signal apparatus
suitable for signalling in or on railway trains, simple in construction,
sure of action at any moment, and cheap in the make and mode of
application. For this purpose a cylinder containing compressed air or
gas is provided or made use of. A valve kept to its seat by a spring

page_text: admits pressure to a blowing trumpet through a regulator, consisting
of a diaphragm pierced with one or more very fine holes. The object
of this regulator is to enable a distinct, similar, and audible signal to be
made, whether the pressure of the air, gas, or other fluid is 2 or 10
atmospheres, or any intermediate pressure.
The signalling apparatus may be a whistle, but a blowing trumpet is
preferred, which at the root is made with a chamber containing a long
thin tongue which nearly closes the inlet or root, and which, when
pressure is admitted, comes into vibration. The trumpet mouth is
closed by a flap, and by pulling a string attached thereto and to the
aforesaid valve compressed air or gas is admitted to the trumpet and
a loud alarm signal is sounded.
f.
The valve spindle may if desired be fitted with a catch and spring
so that it remains open after being once-opened. The string or bell pull
ought to be fitted to cach compartment of the carriage, and the rest
of the apparatus itself may conveniently be placed on the top and end
of the carriage.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edward Griffith Brower in the Great Scal Patent
Office on the 19th January 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
GRIFFITH BREWER, of Chancery Lane, London, send greeting.
75
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing dato the Nineteenth day of July, in the year
of our Loid One thousand eight hundied 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 Edward Griffith Brewer, Her special
licence that I, the said Edward Griffith Brewer, my executors, admınış-
trators, and assigns, or such others as I, the said Edward Griffith Brewer,
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, usc,
excrcise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for

page_text: rest of the apparatus itself may conveniently be placed on the top and
end of the carriage.
And in order that this Invention may be fully understood, I will
now proceed to describe the same with reference to the accompanying
Sheet of Drawings, of which Figure 1 is a longitudinal section of a
pressure cylinder for a signalling apparatus constructed according to
this Invention; Figure 2 shows the blowing instrument itself in longi-
tudinal section, and Figures 3 and 4 shows the apparatus as applied to
a railway carriage.
A is the cylinder charged with compressed air or gas of, say, 6 to 10
atmospheres pressure A small pipe leads the air or gas from the
cylinder A to the trumpet B. It is well known that the strength or
pressure of the air current has a great influence on the sound it
produces in a blowing instrument, and that often- a too-strong or too
weak current produces no sound
An instrument which produces the same sound with a pressure of
10 atmospheres as with that of 6, or 2, or ½ has not heretofore, it is
believed, been produced The apparatus here described however accom-
plishes the desired object, it consists, when formed as a trumpet, mainly
of a conical sound tube b, a tube or chamber c with a long thin tongue c',
an air chamber d, and a regulating inlet diaphragm e having one or
more quite same holes about 1 to 1 millimeter in diameter, and serving
to break the force of the lughly compressed air or gas, so that a current
of equal force is always let into the trumpet, whereby the tongue c¹ 15
put into vibration. The compressed air is contained in the cylinder A.
Where compressed oil gas is used for lighting the carriages the
cylinder A may be supplied with it. The air or gas from the cylinder A
is supplied to the trumpet B by opening the valve v, and by pulling a
string in a carriage compartment this valve is opened. The valve v
15, by a spiral spring, kept against its seat which is formed in the
casing a. The valve is on the end of a rod 8, which is guided and
passes out through leather or other packing in a stuffing box; its outer
end rests in or against a lever h, which by wire or rope connection or
otherwise is connected to a bell pull in cach compartment.
A spring
may if desired be so arranged, as shewn, as to take into
a catch or nose on the rods, and thus when once the valve is opened
at remains in that position and the trumpet continues blowing; but m

page_text: general this may probably be dispensed with, for the sound will continuo
as long as the passenger pulls the bell pull in the compartment.
Figures 3 and 4 show, as aforesaid, how the apparatus may be fixed
on a carriage, but this is only given as an illustration, and it may
be left to railway companies to fit the apparatus in any desired
position.
The mouth of the trumpet may be closed by a flap, as shown, which
flap is opened simultaneously with the valve by means of the bell
pull in a carriage compartment.
And having thus fully described and ascertained the nature of tlic
said Invention, I declare that I claim, –
-
First The application of any compressed gas or air in a pressuro
cylinder or reservoir in combination with an acoustic sound instrument
for producing train danger signals, as described
Second. The application of an acoustic sound instrument for pro-
ducing sounds by high as well as by low pressure, as set forth and as
described with reference to Figure 2, that is, with regulator or diaphragm
e for admission of the air or gas through one or more very fine holes,
and with the peculiar chamber c and with tongue e for signalling.
Third The general arrangement of the valve casing a on the pressure
cylinder A, as described with reference to Figure 1, for signalling.
In witness whereof, I, the said Edward Griffith Brewer, have
hereunto set my hand and seal, this Nineteenth day of January,
in the year of our Lord One thousand eight hundred and seventy-
six.