in Railway- Brakes
Year: 1888

page_text: FREDERIK ARNOLD HOLLEMAN of Oisterwyk Netherlands, Holland Gentleman
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 has reference to certain new and useful improvements in Railway-
Brakes and I do hereby declare the following to be a full, clear, and exact description
of the invention, such as will enable others skilled in the art to which it appertains
to make and use the same, reference being had to the accompanying drawings and to
the letters or figures of reference marked thereon which form part of this
specification.
Referring to the drawings Fig. 1. is a sectional end view illustrating the connections
between the distributing-main connected with the source of supply, an auxiliary
reservoir and a brake-cylinder and my improved controlling-valve interposed in said
connections. Fig. 2 is a longitudinal axial section of the valve and valve-casing on
an enlarged scale. Fig. 3 is a section of Fig. 2 on line XX and Fig. 4. is a sectional
view shewing the valve in another position.
This invention relates to that system of air-brakes for railway-trains in which the
main reservoir for the compressed air is connected with auxiliary reservoirs that
supply the brake-cylinders.
The invention consists in the combination with the main and auxiliary reservoirs
the brake-cylinder and their connections of a controlling valve interposed in said
connections and in the construction of said valve substantially as hereinafter fully
described and as set forth in the claims.
In the drawings a' indicates the main through which the compressed air is conveyed
to the auxiliary storage-cylinders from the source of supply. a is the valved con-
necting pipe that connects the main with the auxiliary storage-cylinder b¹ through
the valve-casing and connection b, and c is the pipe that connects the auxiliary
reservoir 6 with the brake-cylinder c¹ through said valve-casing and connection b.
The controlling-valve interposed in these connections comprises a cylindrical
valve casing, d provided with the branches d'ď ď ď. To the branch d¹ is con-
nected the pipe b that leads to the auxiliary reservoir & and to the branch. dis

page_text: connected the pipe c that leads to the brako-cylinder c¹. The pipe has a stop-
cock, s¹ for cutting off the connection between the auxiliary reservoir band
valve-casing d.
The branch is connected with the pipe a that leads to the compressed-air
main a¹ and S is the stop-cock in said pipe a for cutting off the communication
between the main a' and the valve-casing d.
To the branch d is connected the exhaust-pipe k and Im are the cylinder-heads
screwed into the cylinder ends and provided with inwardly projecting abutments l¹ m²,
respectively that serve to limit the movements of the valve.
In the inner periphery of the valve-casing and the outer periphery of the valve V
are formed two grooves or passages g and i respectively. The groove or passage g
extends from the branch d¹ toward the length of the casing and serves to establish
communication between the auxiliary cylinder & and the main a' through the valve-
casing and the groove or passage i serves to establish communication between the
brake cylinder c¹ and the exhaust-branch d when the valve is in proper position.
The valve V comprises an open-ended cylinder e divided into two chambers by a
partition e¹.
The said cylinder has a longitudinal groove h formed in its outer periphery into
which projects the end of a screw ¹ Fig. 3 screwed into the valve casing to hold the
valve V against rotation therein yet allowing the valve the necessary reciprocation in
said casing.
The chambers of the valve are provided with buffers p, q, secured therein by means
of pins n, o, respectively Figs. 2, 3 & 4 which buffers I preferably make of wood.
more
The object of using wood for the buffers will be readily comprehended by those
conversant with the operations of these valves as it is obvious that were
elastic buffers employed the recoil of the valve would be sufficiently great to destroy
its function.
It will be seen by an inspection of Fig. 2 that the buffer p does not completely fill
the chamber on the left of the partition e¹ of the cylindrical valve, a chamber being
formed at the left end thereof that communicates by a port or passage f with tho
groove g. The cylindrical valve is fitted within the casing d so as to permit it to
reciprocate freely therein and operates automatically under varying pressures of the
air in the main a¹ and auxiliary cylinder 1.
The operation of the valve may be briefly described as follows: When compressed
air is admitted to the valve-casing from the main a¹ through pipe a and branch d
the valve under the pressure of the incoming air is moved towards the right
to the abutment m' as shown in Fig. 2. The compressed air now passes freely
through, gd into the auxiliary reservoir slight differences in the pressure
in 6 a being always equalized through ƒ and g. The valve V therefore remains
in the position described and cannot be displaced by any lateral movements of the
cars, the valve being held in said position by the pressure of the air above it.
This not only insures the stability of the valve when in the position referred to
but also produces an air-tight closure of d d by the valve V.
Inasmuch as the valve V lies in a plane at right angles to the longitudinal
axis of the car a shock in the direction of said longitudinal axis or a sudden
thrust or motion thereof in said direction will not displace said valve. However
as soon as the pressure in the main a' is reduced or falls below the pressure in
the reservoir say one fourth of an atmosphere for instance--the valve V under
the greater pressure of the air in the reservoir moves to the left of the valve
casing first cutting off the communication between 2 and d next between fand g
Fig. 4 then uncovering the passage leading to pipe c. Compressed air now
passes freely from 6 through 6 the valve-casing d and pipe c to the brake-cylinder c²
to operate the brakes. As soon as the pressure in 6 has been reduced by the
outflow of air to that in the main a' the motion of the valve V toward the left
ceases said valve being again held in its position by the pressure of the air on
the right thereof and above it.
When the pressure in 6' falls below that in a! by reason of the continued outflow of

page_text: air from 6 to c¹, the valve V will again be moved from left to right under the increased
pressure in a cutting off the communication between 6' and c¹ Fig. 4, the brakes
being held applied.
If the valve were moved to the limit of its stroke toward the right by the excess in
the pressure in a¹ the brakes would not be applied for the reason that communication
between d and d* would be established and the air in brake-cylinder c¹ exhausted and
lost. This cannot take place for the following reasons:
First the excess in the pressure of the air in a' is too slight to overcome the pressure
of the air in upon the valve, and, secondly because the excess in the pressure is
annulled as soon as the valve V has moved sufficiently toward the right to establish
communication between the port or passage f and the passage g. The brakes may
therefore be operated under any desired pressure with my improved valve. If the
pressure in the main a' is now restored to its normal pressure the excess of such
pressure will overcome the resistance to the motion of the valve exerted by the pressure
in and said valve will return to its normal position (shown in Fig. 2) thereby
establishing communication between the branches d' d' through the passage i exhausting
the air from the brake-cylinder c¹ and releasing the brakes.
Although the valve V is fitted in its casing to form a tolerably-tight joint so as to
cut off the communication between d³ & d¹ when the valve is in proper position yet
it has sufficient play in said casing so that the said joint cannot be regarded in any
manner as an absolutely hermetic one.
The valve only forms a tight joint with that part of the casing into which the
branches open that is to say with the lower part of the casing as hereinabové
set forth and for the purpose mentioned.
The valve operates therefore somewhat like a float between the two strata of air
in a and and their connections thereby insuring simultaneous operation of the
valve of every auxiliary cylinder of a train.
Although the valve does not fit absolutely air-tight in its valve-casing no loss of
compressed air can take place along the valve provided the engineer or the person
that controls the brake power will not allow a greater volume of compressed air to
escape from the main than that which corresponds to the reduction of the pressure in
the auxiliary cylinders.
In determining the diameter of the valve and its casing the co-efficient of friction
must be taken into consideration and said diameter should be so chosen that the
valve V will move readily and rapidly from m¹ to l under a given reduction in the
pressure in the main a' and that said valve will not at once move from back to m¹
under a slight increase in the pressure in a¹. The products of condensation in the
described valve cannot accumulate within the casing as they are completely exhausted
therefrom; hence there is no danger of the valve becoming inoperative in cold weather
and as the valve is more or less lubricated by the petroleum no water can find a
lodgment between the valve and its casing by capillary attraction.
:-
Having now described my invention, what I claim is :-
1. The herein-described valve for air-brakes, comprising a valve casing provided
with branches for connection with the compressed air main, the auxiliary cylinder and
the brake cylinder respectively also with a longitudinal groove or passage in its inner
periphery in communication with the auxiliary cylinder or branch and with an
exhaust-port diametrically opposite said longitudinal passage in combination with a
cylindrical valve fitting snugly but moving freely in the corresponding bore of the
casing said valve being provided with an admission port adapted to communicate with
the passage of the casing and with an exhaust-port communicating at all times with
the exhaust-port of the casing and adapted to establish communication between the
said port and the brake-cylinder branch substantially and for the purposes specified.
2. The herein-described valve for air-brakes comprising a valve casing provided
with branches for connection with the compressed air-main, the auxiliary cylinder and
the brake cylinder respectively also with a longitudinal passage in its inner periphery
in communication with the auxiliary cylinder branch and with an exhaust-port

page_text: diametrically opposite said passage, in combination with a cylindrical valve fitting
snugly in the corresponding bore of the casing and having a motion at right angles
to the direction of motion of the car, said valve being provided with a port adapted
to communicate with the longitudinal passage in the casing and with an exhaust-
passage communicating at all times with the exhaust-port of said casing and adapted
to establish communication between the said exhaust-port and the brake cylinder
branch, substantially as and for the purpose specified.
3. The combination with the main a' the reservoir and the brake-cylinder c' of
the valve-casing d provided with branches d' d³ respectively connected with the
main the reservoir and cylinder an exhaust-pipe or branch d' and a groove or
passage and the cylindrical valve V provided with a port or passage fadapted to
communicate with the groove g and a groove i communicating at all times with the
exhaust-port and adapted to establish communication between said port and the
branch a substantially as and for the purpose specified.
4. The combination with the valve-casing d constructed as described of the valve V
composed of a hollow cylinder divided interiorly into two chambers by a partition and
having a port f leading from one of said chambers and a longitudinal groove or
recess, in its periphery substantially as and for the purpose specified.
5. The combination with the valve-casing d constructed as described and having
inwardly-projecting abutments formed on the heads thereof of a valve composed of a
hollow cylinder divided interiorly into two chambers by a partition and buffers
arranged within said chambers substantially as & for the purposes specified.
6. The combination, with the valve-casing d, constructed as described, and having
abutments of unequal length projecting inwardly from the heads thereof, of a valve
composed of a hollow cylinder divided interiorly into two chambers of unequal length,
a buffer block completely filling the smaller chamber and adapted to contact with the
shorter abutment, and a buffer block partially filling the longer chamber and adapted
to contact with the longer abutment substantially as and for the purpose specified.
Dated this Second day of May One thousand eight hundred and eighty-eight.