Improvements in Pneumatic Brake Apparatus.
Year: 1892

page_text: Date of Application, 5th Jan., 1892-Accepted. 6th Feb
15:00
COMPLETE SPECIFICATION.
[Communicated from abroad by CHARLES GOODWIN EMERY, of New York City,
New York, United States of America, Manufacturer.]
Improvements in Pneumatic Brake Apparatus.
I, OLIVER IMRAY, of No. 28, Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
This invention relates to pneumatic brake apparatus of that kind in which a
cylinder contains a piston with an air reservoir at its one side communicating with
the working chamber on the other side through a valved passage, all so arranged
that when pressure in the train pipe is released, the compressed air in the reservoir
moves the piston so as to put on the brakes and when the pressure in the train pipe
is restored the brakes are taken off.
The chief objects of my invention are to simplify the apparatus of the automatic
air brake to provide against leakage at the stuffing box of the brake cylinder
causing the brakes to creep on, and to give means of applying the brakes several
times if required on a vehicle disconnected from the main reservoir of the train.
For this purpose, I construct and arrange brake apparatus as I shall describe
with reference to the accompanying drawings.
Fig. 1 is a plan and Fig. 3 a side view of parts of an automatic brake apparatus
to. which my invention is applied.
Fig. 2 is a longitudinal section of the brake cylinder.
Fig. 4 is an elevation partly in section showing a modification in the brake
piston, and
Fig. 5 shows part of the packing spring of the piston shewn in Fig. 4.
1. is the brake cylinder having at its one end a head 2, with a port 3, and at its
other end a head 4 with stuffing box 5 for the brake operating piston rod 6, which
is rigidly attached to the piston 7. The piston 7 has through it a passage 8 putting
the working cylinder 9 at the one side of the piston in communication with the
compressed air reservoir 10 on the other side of the piston.
The passage 8 is furnished with a check valve 14, which permits air to flow
from 9 to 10, but prevents air from passing back from 10 to 9.
In the compressed air reservoir 10 are arranged two retractile helical springs 15
of considerable power connected at one end to the piston and at the other end to
he cylinder head 4, so that they tend to draw the piston in a direction to release
he brakes, compressing the air in the reservoir 10.
The port 3 communicates with a release valve 16 with which the train pipe 17
nd a branch pipe 18 are connected. This valve 16 may be of any known con-
truction which will automatically allow air to escape from the brake chamber 9,
ither slowly into the brake pipe or rapidly into the atmosphere, when the pressure
the train pipe is gradually or suddenly reduced.
When the train pipe is charged with compressed air, air flows into the cylinder 9
d through the passage 8 into the reservoir 10, thus producing equal pressure on
oth sides of the piston 7.
On allowing the air to escape from 9. through the release valve, the air in 10
pands, moving back the piston so as to put on the brakes.
For releasing the brakes, the air is admitted to 9 to raise the pressure behind
e piston whereupon the springs 15 move the piston forward to take off the
akes.
The reservoir 10 can be put in communication with the cylinder 9 through a
-pass pipe 18 having a valve or cock 19

page_text: pipe or the part 17 thereof, so that if the vehicle be disconnected from the train,
and the guard's valve 20 be moved to release the pressure from the pipe 17 and
from the cylinder 9 the brakes can afterward be taken off by opening the
cock 19 allowing compressed air to flow through the by-pass pipe 18 to the
cylinder 9, whereupon the springs 15 draw forward the piston 7 to release
the brakes.
The valve 19 being then closed, the guard's valve 20 can again be moved to
release the pressure from the pipe 17 and cylinder 9, and so put on the brakes a
second time; and if then the guard's valve be closed, the brakes can be again taken
off by opening the valve 19.
Thus it is possible to apply and release the brakes several times on a vehicle
which has been disconnected from the train and therefore from the main reservoir
of compressed air.
When the release valve 16 is separate from the cylinder, it should be placed
between the cylinder and the point where the by-pass pipe 18 is connected to the
train pipe.
The valve 19 of the by-pass pipe as well as the valve 20 is preferably placed
inside the vehicle as shewn in Fig. 3, so that both can be conveniently worked by
the guard. The by-pass pipe and its valve may however be otherwise arranged
with any suitable means for conveniently working the valve.
As in case of reduction of pressure in the reservoir 10 the piston moves forwards
in a direction to take off the brakes, there is no danger of leakage at the stuffing
box 5 causing the brakes to creep on, and thus the arrangement of cylinder reservoir
and piston described effectually provides against accidents from this cause.
I do not confine myself to any particular construction of valve 14, which may be
of any suitable kind to allow air to pass from the cylinder 9 to the reservoir 10,
but to prevent return of air from the reservoir to the cylinder.
In the modification shewn by Figs. 4 and 5, instead of employing a check valve
such as 14, I construct the piston with a pair of discs 8" and 9 clamping between
them a cup shaped packing 10 of raw hide, leather or like material having a lip or
flange 12 at its edge bearing against the internal surface of the cylinder. An
expansible ring 13" consisting of a helical spring bent into circular form, is arranged
in an annular seat 14" and presses the flange 12" against the internal surface of the
cylinder preventing air from passing from 10 to 9 but permitting air to pass freely
from 9 to 10, the lip 12* thus operating as a check valve.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. In pneumatic brake apparatus, a combined cylinder and air reservoir separated
by a piston, a check valve which admits air from the cylinder into the reservoir but
prevents air from returning, a piston rod connected to the brake levers passing
through a stuffing box at the end of the reservoir, and springs which urge the
piston in a direction to take off the brakes and farther compress the air in the
reservoir, substantially as described.
2. In combination with the apparatus referred to in the preceding claim and the
train pipe connected therewith, a by-pass pipe with cock or valve for putting the
reservoir in communication with the cylinder so as to operate the brakes while
the vehicle is disconnected from the main air reservoir, substantially as described.
Dated this 5th day of January 1892.
ABEL & IMRAY,
Agents for the Applicant.