IMPROVEMENTS IN APPARATUS FOR OPERATING CONTINUOUS BRAKES FOR RAILWAY TRAINS BY COMPRESSED AIR."
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by James Steel at the Office of the
Commissioners of Patents on the 21st March 1877.
JAMES STEEL, of Glasgow, in the County of Lanark, North Britain, Engineer.
"IMPROVEMENTS IN APPARATUS FOR OPERATING CONTINUOUS BRAKES FOR RAILWAY
TRAINS BY COMPRESSED AIR."
This Invention, which relates to improvements in apparatus for operating con-
tinuous brakes on railway trains by means of compressed air, consists of a hollow
cylindrical vessel which is placed horizontally underneath the floor of each vehicle.
This cylindrical vessel is provided with a hollow or recessed or flat cover at each
end, and, at or near or between the joint made by the covers with the cylindrical
vessel, an elastic diaphragm or bag of india-rubber or leather, preferably corrugated
so as the more easily to be expanded or contracted or moved horizontally is fixed.
Into the centre of each such elastic diaphragm or bag, a metallic draw bar, is fixed
by a strong metallic joint, so as to be air-tight, and each such draw bar is coupled
by rods to the brake levers at each end of a railway carriage or other vehicle, so
that when the diaphragms or bags are moved horizontally by the action of the com-
pressed air as herein-after set forth, the brake blocks are applied to or withdrawn
from the wheels. The hole through which the draw bar passes out of each of the
ends or covers of the cylindrical vessel is kept air-tight by means of an elastic sleeve
or tube surrounding it, after the manner of that set forth in the Specification of the
said James Steel, No. 2721, A.D. 1875, but it is preferred to pass it through a
stuffing box fitted with one or more cup leathers, acted upon by a spring and
gland.
Pipes or passages are provided for the purpose of admitting air to both sides of
the elastic diaphragms or bags, and when the air is on both sides the brakes are out
of action.
To apply the brakes the air is withdrawn from the space between the two
diaphragms or bags, which allowing that on the other side to expand forces the
diaphragms or bags inwards, so that they at once put the brake blocks on to the
wheels.
To withdraw the brakes compressed air is re-admitted to the space between the
diaphragms or bags, which forces them and the brake gear connected with them

page_text: inwards, that is to say, into their normal position of being off. The valvular and
cock arrangement for the foregoing purposes are on the engine, and operated by the
driver from the foot plate, being substantially the same as those set forth in the
aforesaid Specification No. 2721, A.D. 1875.
Another improvement comprised under the present Invention is applicable not
only to the apparatus herein-before set forth, but also to the other air brake
apparatus for which Letters Patent have been previously granted to the said James
Steel and John MoInnes, namely, No. 74, A.D. 1874, and to the said James Steel,
No 623 and 2721, A.D. 1875.
This improvement relates to apparatus for enabling passengers to at once apply
the brakes to a train on an occasion of emergency without incurring the dangerous
delay of first communicating with the guard or driver. It consists of a cock placed
on the end of each carriage, and communicating with the air escape side of each
piston, diaphragm, or bag, or to the spaces outside each pair of pistons, diaphragms,
or bags, or to pipes attached thereto. The plug of each cock is fitted with a lever,
to which a light chain or strap is connected passing to the interior of each carriage
over the heads of the passengers, and the rim of the eye of the lever is notched,
into the notches of which the point of a pawl or spring catches.
When a passenger pulls the chain or strap for the purpose of allowing the air to
escape in order to apply the brakes, the chain hangs loose inside the carriage, and at
the same time the lever on the cock or valve which has been opened is held up
by means of the catch or pawl, so that the carriage and compartment from which
the brake has been applied is at once detected, and thus a check is provided against
the improper use of the passenger brake appliance.
Another improvement comprised under the present Invention is an automatic
charging and escape valve for the purpose of admitting air to the cylinders, and
rapidly withdrawing it at the instant the brakes are to be applied. This consists
of a double valve, that is to say, one valve inside the other, the inner valve being
inverted. A hole is bored down through the inner valve through which the air
passes into the cylinders as it is admitted to the pipes throughout the train for
the purpose of putting the brakes off, and when the pressure is taken off the pipes
for the purpose of putting the brakes on, this allows a spring on the under side of
the valve to re-act, which at once shuts the inner valve and lifts it with the outer
valve, thereby exposing openings close to the cylinders through which the air at
once escapes into the atmosphere, so that the cylinders are instantly emptied, and
consequently the brakes are instantly applied with full force which cannot take place
when the air has to escape through a long length of pipe.