IMPROVEMENTS IN VACUUM BRAKES
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by John Audley Frederick Aspinall at
the Office of the Commissioners of Patents on the 23rd October 1878.
JOHN AUDLEY FREDERICK ASPINALL, of Inchicore, Dublin, in the County of
Dublin, Engineer. "IMPROVEMENTS IN VACUUM BRAKES."
The main object of this Invention is to render existing vacuum brakes, such as
Smith's and Hardy's automatic, and my Invention may be applied to trains already
fitted with such brakes.
According to this Invention I adapt a so-called "Hardy sack" to my automatic
system by fitting the same with a lower cover closed to the atmosphere, and I pass
the pulling rod connected to the diaphragm through a stuffing box or cup leather
in this cover. I also fit the leather diaphragm with a valve opening downwards,
and connected to a pipe leading to a three-way cock or valve referred to herein-after.
I also connect the interior of the sack with the said cock or valve.
I also according to this Invention adapt a so-called "Smith sack" to my
automatic system by placing the said sack inside a metal cylinder, the pulling rod
passing through a stuffing box or cup leather. I fit the top of the sack with a valve
opening downwards, so as to allow of air being drawn out of the metal cylinder
and the sack. I connect both with the aforesaid three-way cock or valve.
I place a. cock of such a description at each end of a carriage or engine, and
arrange them opposite or right-hand at one end and left-hand at the other. This
cock may be of the following construction:-It has a shank at the top communi-
cating with the two coupling hose pipes, and two shanks below or laterally, one
connected to the pipe leading to the bottom part of the sack, and which I call " the
automatic pipe," and the other connected to the pipe leading to the top part of
the sack, and called the "vacuum pipe."
By this arrangement I am enabled to work the brake either as an automatic
vacuum brake, or as an ordinary vacuum brake, such as the Smith system.
The mode of working the brake automatically, say with a "Hardy sack," is as
follows: The ejector or pump on the engine is made to produce and maintain a
vacuum in the automatic pipe, which runs throughout the train, and communicates
with the bottom of every sack in the train. The vacuum pipe communicates with
[Price 21

page_text: the top or interior of the sack, and is closed at both ends when the brake is working
as an automatic brake. When air is drawn out of the automatic pipe by the ejector
or pump the valve on the sack opens and allows the air to flow out of the interior
of the sack, and as long as a vacuum is maintained in the automatic pipes_the
leather diaphragm remains at the bottom of its casing because it is in equilibrium.
In order to apply the brakes air is admitted to the automatic pipes; the valve
on the sack then closes at once, and as there is a vacumm above the leather
diaphragm-it-is-by-the-force-of-the-atmospheric-air-pushed-to-the-top-of-its-casing,
and the pulling rod which is connected to the brake gear applies to the brakes.
To take off the brakes the valve admitting the air is closed, a vacuum is once
more formed in the automatic pipes and therefore under the leather diaphragm,
which falls and releases the brakes.
"
""
As in running into terminal stations the brake would remain on when the engine
is detached, air can be admitted at the top of the sacks by opening one of the three-
way cocks so as to communicate with the vacuum pipe" and the atmosphere.
When the automatic brake is being used the plug of this cock is so turned that the
automatic pipes communicate with the ejector or pump, and the "vacuum pipes
are closed to the atmosphere. When the simple vacuum brake is being used the
plug of the cock is turned so that the vacuum pipes" communicate with the
ejector or pump, and the automatic pipes through an opening in the end of the plug
communicate with the atmosphere, so that the air can enter below the diaphragm
and raise it and close the same, thus applying the brake as soon as a vacuum is
formed in the vacuum pipes and in the top of the sacks.
The brake gear on the engine may be so arranged in connection with a cock or
valve that when the driver applies the brake by admitting air to the automatic
pipes he at the same time throws the ejector in communication with the top part
of the sack under the engine only, and by creating a greater vacuum above the
diaphragm he can apply the brake with greater force to the engine and tender
wheels.
The bottom part of the "Smith sack" may as described be fixed to the iron case,
and the top part fitted with the valve opening downwards; or the sack may be
hung from the top of the casing, allowing it to be distended when the brakes are
off, and vice versa.