IMPROVEMENTS IN THE MEANS AND APPARATUS FOR WORKING BRAKES ON RAILWAY TRAINS
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Edward Tyer at the Office of the
Commissioners of Patents on the 28th January 1878.
EDWARD TYER, of No. 4, Old Street, Finsbury, in the County of Middlesex.
"IMPROVEMENTS IN THE MEANS AND APPARATUS FOR WORKING BRAKES ON RAILWAY
TRAINS."
My Invention relates to means and apparatus whereby the lateral oscillation or
play of a railway carriage in relation to its wheels and axles is utilised in
accumulating power for the purpose of working the brakes attached to such
carriage.
Within the
For this purpose I mount on the carriage a lever, one arm of which has a roller
adjusted so as nearly to bear on or against the boss or other convenient portion of
one of the wheels of the carriage, or against a disc or collar on the axle. The other
arm is pressed downwards by a spring or weight. The axle of the roller works an
eccentric or crank which gives motion to the piston of an air pump for the com-
pression or exhaustion of air or other fluid contained in a reservoir.
cylinder of this pump I arrange two pistons and rods, the one being the working
piston, and the other piston in its normal position being pressed against a fixed stop
by means of a spring. I pack both these pistons with cup leathers, having their
lips turned in the same direction, so that they act as suction and discharge valves
respectively.
The end of the cylinder beyond the second piston communicates with a reservoir
on the carriage, into which air is compressed, or from which air is exhausted, by
every stroke of the working piston.
The spring piston forming the bottom of the pump allows for variation of stroke,
jar, or concussion, and at the same time ensures that the whole stroke of the
working piston is effective.
The roller is set a short distance from the boss of the wheel, and only comes into
contact therewith during the lateral play or side shake of the carriage with relation
to its wheels and axles. When this lateral movement takes place the roller is
caused to rotate by frictional contact working the pump.

page_text: When the lateral play of the carriage takes place in the opposite direction, then
the roller ceases to rotate and the pump stops. By this arrangement the action
of the pump is rendered intermittent, thus preventing the generation of great
heat.
From the reservoir pipe provided with a three-way cock or valve is connected to
any suitable brake working apparatus, which consists of cylinders, fitted with
pistons, or of extensible vessels, such as bellows, or flexible bags, constructed and
connected by brake gearing to the brake blocks in any known manner.
The lever carrying the roller may be connected to the piston of a small cylinder
communicating with the reservoir so arranged that when the pressure in the
reservoir has attained the maximum required, the piston of the small cylinder with-
draws the roller from the range of action, thus preventing the action of the
pump.
When by an application of the brakes the pressure in the reservoir has been
altered, the piston in this small cylinder ceases to keep the roller out of range, and
the pump is again worked till the pressure is restored to its normal amount.
There may be more than one cylinder or extensible vessel for working the brakes
on each carriage, and in this case I connect them all by branch pipes with the one
three-way cock or valve.
In order to work simultaneously these cocks or valves on several carriages of the
train, I provide a cord or chain connected from carriage to carriage, and passing
round pullies fixed to weighted arms that work the cocks or valves, so that when
this cord or chain pulled either forwards or backwards at any point, the several
coks or valves are shifted so as to put on the brakes of the several carriages; and
when the cord or chain is slacked out, these cocks or valves are shifted back to
their normal position by the weighted arms as above described so as to take off the
brakes. In this manner, by extending the cord or chain throughout the train,
brakes may be applied to all the wheels thereof by a pull of the communicating
cord or chain from the engine, or from a guard's van, or other part of the
train.
'
In order to provide for keeping the brakes on when a train is divided, I arrange
a spring buffer which forms a stop for each of the weighted arms that work the
cocks or valves when it is subjected to its ordinary working pull. When these arms
are subjected to an unusual strain, such as would break the communicating cord or
chain on the division of the train, the spring buffers yield, allowing the arms to
move a little beyond their usual extent or stroke, so that they become engaged by
catches which hold them in the position for keeping the brakes applied, notwith-
standing the fracture of the communicating cord or chain.
When pumps worked as above described, instead of being used for compression of
air, are applied for the rarefaction of air in a reservoir, the excess of atmospheric
pressure in that case causes the application of the brakes.