AN IMPROVED PNEUMATIC SIGNAL APParatus
Year: 1871

page_text: PROVISIONAL SPECIFICATION left by Charles Wedderburn Granville
at the Office of the Commissioners of Patents, with his Petition,
on the 17th October 1871.
I, CHARLES WEDDERBURN GRANVILLE, late of Mansfield Chambers,
St. Ann's Square, Manchester, but now of Arundel Street, Strand, in the
County of Middlesex, Merchant, do hereby declare the nature of the
said Invention for "AN IMPROVED PNEUMATIC SIGNAL APParatus,” to be as
follows:-
.
My said Invention relates to a simple, economical, and efficient
pneumatic apparatus, which may be used in railway, trains for com- .
munication between the passengers and guard or driver, or between
the guard and driver; on board steam ships for transmitting orders to
the engine room; in houses and other buildings to give alarm in cases
of attempted burglary; and for other similar purposes.
The construction and operation of this apparatus will be essentially
the same for all of these purposes, although its details may be modified
to adapt it to the circumstances, of cach particular case.
'

page_text: The said apparatus is constructed with a strong air-tight chest or
chamber. This chamber has on one end or at any other convenient part
a small tube, which carries a whistle or horn. This tube is also provided
with a valve or cock, placed between the chamber and the whistle. The
said chamber also has a valve for admitting air into it; the air is forced 5
into the said chamber by an ordinary air pump or other suitable
contrivance, which may be attached permanently to the apparatus, or
may be connected to the chamber when required, and disconnected when
the chamber is filled with air. I prefer that the chamber should also
be provided with a pressure gauge. The valve in the whistle tube is 1
connected to a cord or line which is extended to any desired position,
and by pulling this cord the valve is opened and the whistle sounded.
When the said apparatus is used for effecting communication between
the passengers and guard or driver of a railway train, the apparatus has
a flag attached to the rod of a small piston fitted in a tube projecting 1
from the top of the air chamber. When the said chamber is filled with
air this piston is kept up in the tube and the flag is plainly exhibited,
but when the air is exhausted or partially so the piston falls in the tube
and the flag is drawn down. The cord or line connected to the whistle
valve is conducted over suitable guide pullies to a convenient position 2
inside the carriage. I can obtain a sufficient pressure of air in the chest
to blow the whistle or horn very loudly, and so that it can be plainly
heard from one end of the train to the other. I prefer to place one
apparatus on each carriage, as I then avoid all difficulty about
connections in making up or dividing a train; but this arrangement is 2
not absolutely necessary. A cord or line attached to the valve of each
apparatus is also secured to the next carriage to give an alarm if the
train separates. .
When used on board steam vessels for the transmission of orders to
the engine room,
the different orders may be indicated by the number of 3
times the whistle is blown; or the whistle may be sounded simply to
attract attention to signals given by an index or pointer moved by a
piston in the same manner as the flag above described, or by other
suitable contrivances in connection with the air chest or chamber.
For preventing burglary I place the aforesaid apparatus in a bedroom, 3
and connect the whistle valve by cords or lines to the doors or windows
desired to be protected or guarded in such a manner that the opening

page_text: of either of such doors or windows will pull the cord or line, or break
the same, and so open the valve and sound the whistle. When the
apparatus is applied to the purposes first above named,. I prefer that by
a spring or otherwise the whistle should close as soon as the cord is
released, but when used for preventing burglary the valve must remain
open so that the whistle will give a prolonged sound. Instead of
connecting the cords or lines to the doors or windows, I may arrange
them in such positions in the rooms or passages or on the staircases of
the house, that any persons unacquainted or unfamiliar with the same
will be sure to disconnect or disturb the said lines, and thereby give the
I however do not consider the arrangement of these cords or lines as
forming any part of my Invention, which relates solely to the apparatus
constructed and operating as above described.