Improvements in the Mechanism of Fluid or other Pressure Brakes.
Year: 1890

page_text: Date of Application, 14th Aug., 1890-Accepted, 22nd Nov., 1890
COMPLETE SPECIFICATION.
Improvements in the Mechanism of Fluid or other Pressure Brakes.
We, HENRY SHAW and EDWARD SHAW, of No. 9 Central Arcade, Sydney, in the
Colony of New South Wales, Australia, Engineers, do hereby declare the nature of
our invention for "IMPROVEMENTS IN THE MECHANISM OF FLUID OR OTHER PRESSURE
BRAKES," and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement, that is to say :—
Our invention relates to inprovements in the mechanism of fluid or other pressure
brakes, and consists in the interposition, at any suitable part between the continuous
connection pipe, the auxiliary reservoir, and the brake cylinder usually employed for
operating fluid or other pressure brakes, of two classes of valves, to be designated :-
The automatic self-releasing exhaust air valve, in combination with the hand brake
shunting valve.
The office of these valves is to utilize the waste or exhaust air used in operating
the mechanism of railway or tramway brakes, and applying such waste or exhaust
air to the purpose of removing the pressure from the brake blocks when required
to do so, instead of allowing it to pass into the open air; and also for the purpose
of shunting single or detached carriages by operating the valve mechanism from the
side of such carriage, and using the air which remains in the auxiliary reservoir.
By the aid of these valves we are enabled to do away absolutely with the use of
spiral or other springs such as are now in use for performing the operation of
releasing the brake blocks, and which necessitate the application of additional power
to counteract the pressure incident to the placing of such springs on the reverse side
of the brake piston and in the other parts of the valve mechanism.
Our improvements further consist in constructing the brake cylinder with two (2)
separate compartments, to be called respectively, the brake pressure cylinder, and
the brake release cylinder, the piston of the former being of smaller area than the
latter, so that the air which has been used for putting on the brake, when it enters
by the medium of the interposed valve into the brake release cylinder, may perform
a similar work to that which it performed in the brake pressure cylinder, with the
exception that it operates in the reverse direction.
To carry out the object of our invention, we construct a series of chambers and
passages and place same in close contiguity to the ordinary brake cylinder; these
chambers and passages are of suitable dimensions and are fitted with self-adjusting
valves so arranged that the pressure of the exhaust air shall operate on the reverse
side of the piston instead of passing away direct to the atmosphere.
A small
We construct a cylinder which we term a drip cup, to receive the air from the
continuous connection pipe which is usually connected with the air pump.
aperture suitably placed in said drip cup, conveys the air into an adjoining chamber
fitted with a cup headed piston having a central stem, to which is attached a slide
valve of the ordinary description, seated so as to cover ports or air-ways com-
municating with a double valve in the one case, and a single valve in the other
case, the respective areas of these valves being arranged according to the pressure
operating them.
The stem of the double valve at one end is prolonged for the purpose of securing
contact with the single valve, which, when moved the desired distance, allows the air
to pass into the release cylinder, in which position a communication is also established
between the auxiliary reservoir and the brake cylinder whose induction pipe also
acts as an eduction pipe to convey the air back to valve chamber and thence to the
release cylinder, so that the releasing spring which is usually placed against the piston
is not required, and thus the exhaust air is made to perform the same duty as the

page_text: spring for the time being, and after performing such duty, when the brakes are
again put on, will return by the connection referred to, and thence to the open air,
thus allowing the operation of putting on the brakes to be effected without the
resistance or back pressure consequent upon the existence of the spring.
In combination with the apparatus just described we use a hand brake valve, so
placed, that the air remaining in the auxiliary reservoir may be used to operate the
brake by hand during the performance of shunting and like work, when the air
pipe is detached from the engine or air pumps. This valve is attached to any suit-
able part of the drip cup, as shewn, and consists of a double seated valve operated
by a cam or eccentric, and having also a stem for moving a single seated valve.
To do away with existing brake cylinders and springs, we provide a combined
brake and release cylinder, having two (2) pistons connected with cross heads and
stays, the one to perform the duty of putting on the brake, and the other to receive
the exhaust air, through the medium of the combined automatic releasing exhaust air
valve, or, through the medium of the air brake shunting valve, to put off the brake,
as shown in Figure 7.
The brake pressure cylinder is of a smaller area than the brake release cylinder,
which admits of part of the exhaust air being retained in the former to act as a
sort of cushion, and to be supplemented when required for putting on the brake.
Where existing brake cylinders are utilized we add a release cylinder, to receive
the exhaust air for the purpose of putting off the brake.
Our apparatus is fitted with all the usual attachments for connecting the auxiliary
reservoir, the continuous connection pipe, and the brake cylinder, such as are now
ordinarily used in operating air and fluid pressure brakes.
Our invention is illustrated by the accompanying drawing, in which similar
numerals used throughout the different views indicate similar parts, and in which
Figure 1 is a side elevation of our combined automatic self-releasing exhaust air
valve, and air brake shunting valve.
Figure 2 is a plan of Figure 1.
Figure 3 is a sectional elevation of Figure 1.
Figure 4 is a longitudinal section of our combined brake pressure cylinder, and
brake release cylinder.
Figure 5 is a plan of Figure 4.
Figure 6 is an end elevation of Figures 4. and 5.
Figure 7 is a plan, showing the combination of our mechanism, with attachment
to continuous connection pipe. auxiliary reservoir, and brake cylinders.
In Figure 7, the combined automatic self-releasing exhaust air valve is shewn
without the double and single valve and direct communication established by the
medium of the slide valve, and an exhaust port provided for the escape of the
exhaust air when leaving the brake release cylinder.
In Figures 1. 2. and 3. No. 1 is the lower casing-2 the upper casing of the
exhaust cylinder 3 drip cup-4 inlet passage from continuous connection pipe-
5 inlet passage from shunting valve-6 sleeve and nut forming guide for piston valve
spindle piston valve spindle-8 spring for seating valve, 7,-9 induction passage
.connecting with piston chamber-10 piston chamber-11 pin valve controlling air
supply through central passage in piston head--12 cup headed piston with valve
seating on reverse side-13 central passage in, 12,-14 stem of 12,-15 port or
passage in 14 for admission of air on reverse side of 12,-16 slide valve-17 valve
chamber-18 induction passage for connecting pipe from auxiliary reservoir-19 air
passage to double valve and also return passage for exhaust air-20 small end of
double valve-21 large end of double valve 22 escape passage for exhaust air-
23 outlet in 22,-24 induction passage to brake pressure cylinder and also eduction
passage for exhaust air-25 stem of 21,-26 induction passage for exhaust air to
brake release cylinder and also eduction passage for same-27 valve for outlet of
exhaust air-28 passage for exhaust air-29 escape for exhaust air-30 casing of
shunting valve 31 single seated valve-32 double seated hand valve-33 eccentric
for moving 32, 34 inlet pipe from auxiliary reservoir.

page_text: In Figures 4. 5. and 6.-35 is the brake pressure cylinder-36 piston for 35,-
37 brake release cylinder-38 piston for 37,-39 piston rods-10 cross heads-
41 stays connecting 40,-42 end of 39 for attachment to brake levers.
In Figure 7 similar numbers are used where parts are identical with those
described in previous figures; in this figure-43 is the stop collar on. 39,-
44 continuous connection pipe-45 shunters lever connecting with lever of 33-
46 lever attached to 33,-47 connection between 44 and 3 at 4, 48 cut off tap-
49 auxiliary reservoir-50 connection between 49 and 18,-51 connection between
50 and 34, 52 connection between 24 and 35,-53 connection between 26 and 37,-
29 exhaust into open air.
The method of operating our mechanism for putting on the brake is as follows:-
The air is admitted by 44 and 47 into drip cup 3, and passing through passage 9
into 10, enters through 13 into 15, flowing thence into auxiliary reservoir, which
when fully charged, allows the application of the pressure on the reverse side of
piston 12 to commence.
This movement takes place as the result of a diminution of pressure in chamber 10.
This is an essential safeguard in the event of accident to the continuous connection
pipe.
The air is then admitted through 18 and allowed to pass into 19 by movement
of 16, and operating the double valve at its small end 20 passes thence into 24
and through 52 (see Figure 7) into brake pressure cylinder 35, thus putting on the
brake.
To utilize the exhaust air for the purpose of taking off the brake our mechanism is
operated as follows:-
Upon the increase of pressure, which is brought about in the usual manner by
operating the ordinary driver's brake valve, the piston 12 is put in operation, and
the slide valve 16 moved, so as to cause a return of the air through pipe 52 into 24
and thence, by 26, to release cylinder 37. Upon the application of the air to the
brake pressure cylinder, the exhaust air remaining in 37 returns by pipe 58 through
port 26 and passes into the open air.
The manner of operating our shunting valve when the carriages are detached is
as follows:
The air passos from auxiliary reservoir 49 by pipe 50 into 51, and enters shunting
valve at 34 where the pressure is upon the reverse side of single seated valve 31.
By movement of the shunting lever 45, 46, which is attached to eccentric 33,
causes 33 to rotate sufficiently to lift double seated valve 32 and prevent escape of
air from upper seating lifts 31 and allows the air to pass into drip cup 3 through
passage 5, where the operation previously described for putting on or taking off the
brake is repeated, and this operation may be continued until the air in the auxiliary
reservoir is exhausted.
A partial movement of the eccentric 33 of say th revolution is necessary to lift
double valve 32, causing an escape of air from underside of piston 12 through
passage 5 into open air, and so applying the brake. To release the brake a further
motion of say th revolution of eccentric 33 will seat valve 32, and open valve 31,
establishing communication between auxiliary reservoir 49 thus establishing con-
nection between under side of piston 12 and auxiliary reservoir 49, at the same time
cutting off escape.
It is to be observed that upon the pressure in brake pressure cylinder, 35, and
brake release cylinder, 37, becoming pretty equally divided, the valve 21 being
greater in area than valve 20, will move in the direction of escapement 23, thus
allowing valve 27 to seat itself, and destroying communication between brake
pressure cylinder, 35, and brake release cylinder, 37, the further motion of the
valve 21 will unseat 20, allowing air remaining in 35 to escape through escape-
ment 23 to open air. The pressure in release cylinder thus preponderating will
take off brake, at the same time restoring brake cylinder piston 36 to its normal
position.

page_text: Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In fluid pressure automatic brake mechanism, the use of an automatic self-
releasing exhaust air valve, comprising a primary piston operating a slide valve for
opening and closing passages communicating with a double and single valve, for the
purpose of utilizing the air which has been used for putting pressure on the brake,
to take the pressure off the brake, such primary piston, passages, and valves, being
severally connected with the continuous connection pipe, auxiliary reservoir, brake
cylinder, and release cylinder, substantially as described and shewn.
2. In fluid pressure automatic brake mechanism, the use of a band brake shunting
valve, comprising a double seated valve for actuating a single seated valve, and an
eccentric operated by a lever; such valve being interposed between the auxiliary
reservoir and the automatic self-releasing exhaust air valve referred to in claim 1,—
as described and shewn, and for the purposes set forth.
3. In fluid pressure automatic brake mechanism, the use of a double cylinder
consisting of a brake pressure cylinder and a brake release cylinder, the air for
operating the piston in the latter being obtained from the former through the medium
of an automatic self-releasing exhaust air valves, as described and shewn in Figures 4.
5. 6. and 7.
4. In fluid pressure automatic brake mechanism, the use of an automatic self-
releasing exhaust air valve in combination with a hand brake shunting valve and a
double cylinder comprising a brake pressure cylinder and a brake release cylinder,
such mechanism being severally connected with the continuous connection pipe and
auxiliary reservoir, all substantially as described and shewn, and for the purposes set
forth.
Datad at Sudnay this Samanth day of T.L.. 1900
HENRY SHAW.
EDWARD SHAW.
Witness,
HENRY SHAW.
EDWARD SHAW.
H. A. SMEDLEY.
Haseltine, Lake & Co.,
45, Sonthampton Buildings, London, Agents for the Applicants.