Improvements in or relating to Fluid Pressure Brakes for Railway Vehicles.
Year: 1895

page_text: Date of Application, 8th Oct., 1895-Accepted, 14th Dec., 1895
COMPLETE SPECIFICATION.
Improvements in or relating to Fluid Pressure Brakes for Railway
Vehicles.
A communication from ERNEST CARLETON WEBB, Attorney-at-Law, 181 Broad-
way, New York City, State of New York, United States of America.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
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 an improvement in the appliances, hitherto employed as
a feature of or in connection with "triple-valves," for bringing about a quick-
action emergency operation under abnormal reduction of train-pipe pressure in the
air-brake systems of railway trains. Hitherto, it has been the practice in bringing
about the quick-action emergency stop, to cause pressure to vent from the train-
pipe to the brake-cylinder, to a limited extent and in advance of the flow of
pressure from the auxiliary-reservoir to the brake-cylinder, the train-pipe venting
thus effected operating to quicken the action of the triple-valves on succeeding
cars of the train. While an emergency action is quickened to a very material
extent by the flow of pressure from the train-pipe to the brake-cylinder in the
construction hitherto employed, this quick action is due to the lowering of the
train-pipe pressure, and not, to any material extent at least, to the fact that
the pressure thus vented flows to the brake-cylinder. It has been claimed by
competent experts that the extra flow of pressure to the brake-cylinder from the
train-pipe is a detriment rather than an advantage, for the reason that the pressure
of the auxiliary-reservoir when expanded into the brake-cylinder on top of, or in
addition to, that which has previously entered from the train-pipe, produces
injurious strain upon the lever mechanism, besides skidding the wheels.
In practice the auxiliary-reservoir is usually of sufficient capacity, with relation
to the brake-cylinder, to cause the reservoir pressure under full service or
emergency action to bring about the maximum pressure of the brake-shoes against
the car-wheels, which the brake mechanism is designed to stand or to exert without
skidding the wheels; and, as when the comparatively large emergency port or
passage, between the auxiliary-reservoir and brake cylinder is opened, equalization
of pressure between the two is brought about almost instantaneously, the pressure
vented from the train-pipe to the brake-cylinder does not materially hasten the
movement of the brake-shoes.
The object of this invention is to provide an improved appliance for use in
connection with, and preferably incorporated in the structure of, a triple-valve,
which will operate under the movement of the triple-valve abutment or piston,
when abnormal reduction of train-pipe pressure is brought about, to open and
then close communication between the train-pipe and outside air to vent a limited
extent of pressure from the train-pipe and thus produce the quick-action emergency
operation without danger of straining the brake mechanism.
In the drawings, wherein this appliance is shown as forming a part of a triple-
valve structure,―
Figure 1 is a central vertical section of a triple-valve provided with the
improvements;
Figures 2, 3 and 4, are broken sections taken respectively on lines 2, 3 and 4 of
Figure 1 and viewed in the direction of the arrows ;

page_text: Figure 5, is a bottom-pian view OL the main snde-valve or the triple-valve
device;
Figure 6, is a plan-sectional view of a bushing, the section being taken on line 6
of Figure 3 and showing the seat upon which the valve shown in Figure 5
slides; and
Figure 7, is a broken section taken on line 7 of Figures 4 and 6 and viewed as
indicated by the arrows.
g
A is the main shell or body-portion of a triple-valve containing a piston-
chamber B, having a bushing t; a main valve-chamber C, fitted with a bushing C¹;
and a drip-chamber D. The chamber B is closed by means of a cap-plate E which
is holted to the main body-portion against an intervening gasket . The drip-
chamber D, in practice, communicates at r with the main train-pipe or brake-pipe
of the brake-system, and has a port q opening into the piston-chamber B adjacent
to the cap plate E. In the shell A is a chamber or passage which communicates
with the brake-cylinder, and a port n which communicates with the auxiliary
reservoir. The lower inner side of the bushing C¹ forms a valve-seats, having a
comparatively large port s leading to the brake-cylinder passage p; a port s²,
leading to an exhaust passage m which goes to the outside air; a port s³, of
comparatively small dimensions leading to the brake-cylinder passage p; and a
comparatively large quick-action inlet port * leading to the drip-chamber D.
In the shell A, preferably, though not necessarily, in the position shown, is a
valve-chamber F provided with an exhaust port and a vent passage ¹. In the
valve-seats is a quick-action outlet port which communicates with a passage 2,
preferably cored or cut in the shell about the bushing C and leading to the
chamber F in line with the exhaust port l. Also in the valve-seat s is a small
port communicating with a passage 1³, preferably provided in the outer surface
of the bushing C¹, and extending to the chamber Fat the end of the latter opposite
the vent opening .
C2 is the main slide valve, which may carry the usual spring k. In the end of
the slide-valve is a passage terminating in a valve seat ², beyond which is the
service-passage k³, extending through to the working face of the valve. The end
of the slide-valve at its under side is cut away as indicated to form an emergency
passage k.
In the under face of the main slide-valve are grooves
recesses 5, 6, 7 and 8, all preferably of the relative sizes and in the relative
positions shown in Figure 5.
or
In the chamber B is a piston B¹ having a stem B2 which passes through the
main slide-valve, and at its end carries, or is shaped into, a graduating valve i which
closes against the valve-seat k". Extending transversely through the stem B" is an
elongated slot which receives a pin fastened at its opposite ends in the sides of
the main slide-valve. In the bushing t is a feed-groove t¹, and, in the position shown
at the bushing C, is a feed-groove t². In the chamber F is a velve F, which is
preferably a piston slide-valve, provided with a central circumferential recess h,
which, when the valve is in the normal position shown, registers with and opens
communication between the porte 12, 1. At its end adjacent to the passage the
valve carries a stop-projection which prevents the valve from seating, over its
entire area, against the end of the chamber F. Confined between the valve F¹
'and a screw-plug t³ is a spring 2, which tends to force the valve F¹ to the normal
position shown. In the cap-plate E is a chamber E' closed by means of a screw
plug E. The chamber El opens into the chamber B and contains a buffer Es³
comprising a stem g provided with a collar g' and working in a guide-recess g³ in the
screw-plug E2, and a spring y confined between the screw-plug E and the collar g',
and operating normally to press the latter against a stop 9' afforded by an inward
projecting flange on the cap-plate E. On the pistou B¹ is a stop or buffer
projection B.
This improved valve device is made to conform to standard requirements, in that
it i made to register with the standard fittings provided for triple valve at the
auxiliary-reservoir, brake-cylinder and train-pipe. The firm thow the nuin

page_text: slide-valve at release position whereby air entering at r from the train-pipe fills the
drip-chamber and chamber B and passes through the grooves t¹t to the chamber C
and thence through the port n to the auxiliary reservoir charging the latter, to
equalize its pressure with that of the train-pipe. The slide-valve groove A³ registers
with the ports s¹², whereby any pressure in the brake-cylinder is vented through
the passage m to the outside air. The groove k³ registers with the ports s³ 36 whereby
the chamber F is open through the passage 13. ports s6, 3, chamber or passage p
and ports s¹, s2 and passage m to the outside air. The absence of air under
pressure in the chamber F causes the spring ² to hold the valve Fin normal
position whereby the passage 2 is open through the port to the outside air.
Under a reduction of train-pipe pressure for a service-stop, the piston B₁ is moved
by the preponderance of reservoir-pressure until the projection B³ strikes the
buffer E³. In moving from release to service-stop position the stem B2 advances
until the end of the groove i engages the pin 2 to unseat the valve, and then the
main slide-valve is moved by the engagement of the stem B with the pin i² to
advance the service-stop passage to the port s'.
When the slide-valve is in this
position all the other ports in the valve-seat are closed whereby pressure flows
from the auxiliary reservoir through the passages k, k, s, p to the brake-cylinder.
When pressure in the auxiliary reservoir, through its venting to the brake-
cylinder, falls slightly below that in the train-pipe the piston B₁ is moved to seat
the graduating-valve i and close the passage in the usual manner. A rise of
train-pipe pressure, to release brakes, will move the valve-mechanism back to the
position shown whereby the brake-cylinder is vented.
Under abnormal reduction of pressure, for an emergency-stop, the piston B' is
forced the full limit of its traverse, under the auxiliary-reservoir pressure, to
compress the buffer Es and bear against the cap-plate E. This causes the slide-
valve to be moved to the position wherein the recess k registers with the ports st so
causing air from the drip-chamber D, and the train-pipe, to flow through the
ports, s, passage 12 and
port 1, to the outside air. It also causes the groove k to
register with the ports and the emergency passage to register with the
port s'. Owing to the large size of the passage full reservoir pressure expands
almost instantly into the brake cylinder to set the brakes with full force As
pressure from the auxiliary reservoir enters the passage p, it also flows through the
port s³, groove k', port s6 and passage 13 to the chamber F, and, by overcoming the
resistance of the spring ², slides the valve F¹, in the direction of the screw-plug t³,
to close communication between the passage 12 and the exhaust-port 1. In practice
the quick-action passage between the train-pipe and outside air (through the
ports, valve-recess, port 85, passage 12, recess of the valve F' and port 1)
should be large enough to cause the desired extent of pressure to vent from the
train-pipe before the quick-action passage is closed by the valve F¹ under the
action of the reservoir or brake-cylinder pressure flowing through the passage 13.
The valve F will remain closed until train-pipe pressure is again raised sufficiently
to move the main slide-valve to release position, when the pressure in the chamber F,
which holds the valve F¹ closed, will vent through the passage 1³, port 6, slide-
valve groove and port to the chamber p, and pass out at m with the brake-
pipe pressure. By providing the passages of proper size with relation to each
other and to the tension of the spring 2, the quick-action emergency operation
may be produced, to all intents and purposes, with the same speed and effect as
with the quick-action appliances hitherto in general use.
The gist of this invention lies, broadly stated, in providing a normally closed
vent passage, between the train-pipe and outside air, at or adjacent to the triple-
valve, main-valve mechanism movable only under emergency reductions of train-
pipe pressure to open said passage, and supplemental valve-mechanism governed by
and following the action of the main valve-mechanism to again close said passage;
and although the mechanism shown and described is that which is preferably
employed, the invention may be carried out with mechanism variously modified.
The improvements are not therefore confined to the details shown and described,

page_text: because they may, obviously, be mɔlifiel without departing from the spirit of th
invention as defined by the cinims.
Having now particularly described & ascertained the nature of the said
invention as communicated to me by my foreign correspondent & in what manner
the same is to be performed, I declare that what I claim is :-
1. In the triple-valve device of a fluid pressure automatic brake mechanism, the
combination of a chamber or casing having direct connections to a brake-pipe and
to the outside air, respectively, main slide-valve of the triple-valve device normally
closing the communication between said connections and movable only under the
emergency reduction of brake-pipe pressure to open said communication, and
supplemental valve-mechanism governed by and following the action of the main
slide-valve to close said communication, substantially as and for the purpose set
forth.
2. In the triple-valve device of a fluid pressure brake-mechanism, the combination
with the main slide-valve and its seat, of a quick-action emergency inlet-port in
the seat communicating directly with the brake-pive, a quick-action emergency
outlet port normally open through a passage to the outside air, the said main
slide-valve normally closing communication between said ports and movable only
under the emergency reduction of brake-pipe pressure to open communication between
said ports, and supplemental valve-mechanism governed by and following the said
action of the main slide-valve to close said passage, substantially as and for the
purpose set forth.
3. In a fluid pressure automatic brake-mechanism, the combination of a brake-
pipe, a brake cylinder, an auxiliary reservoir, and a triple-valve device having
main-valve mechanism whose preliminary traverse under service reduction of
brake-pipe pressure admits air from the auxiliary reservoir to the brake-cylinder,
and which by a further traverse under emergency reduction of brake-pipe pressure
vents air directly from the brake-pipe to the outside air, and having supplemental
valve-mechanism governed by and following the emergency action of, the main-
valve mechanism to close communication between the brake-pipe and outside air,
substantially as and for the purpose set forth.
4. In the triple-valve device of a fluid pressure brake mechanism, the combination
with the main slide valve mechanism and its seat, of a quick-action passage between
the brake-pipe and the outside air normally closed by the main slide-valve, a
chamber in said passage, ports in said seat governed by the main slide-valve and
communicating respectively with the brake-cylinder sage and with the said
chamber, a normally open supplemental valve in said chamber movable under
pressure from the brake-cylinder passage to close the said quick-action passage,
the main slide-valve operating only under an emergency reduction of the brake-
pipe pressure to move and open the quick-action passage and then establish
communication between the said ports whereby pressure from the brake-cylinder
passage flows to the said chamber and closes the said supplemental valve,
substantially as described.
5. In the triple-valve device of a fluid pressure brake-mechanism, the combination
with the main slide-valve mechanism and its seat, of a quick-action passage between
the brake-pipe and outside air normally closed by the main slide-valve, a valve
chamber interposed in said passage, ports in said seat governed by the main slide-
valve and communicating respectively with the brake-cylinder passage and with
the said valve chamber, a supplemental slide-valve in said valve chamber normally
maintaining the said quick-action passage open through said chamber and movable
to close the passage under pressure from the brake-cylinder passage, the main
slide-valve operating only under an emergency reduction of train-pipe pressure, to
move and open the quick-cetion passage and then establish communication between
the spid ports, whereby pressure from the brake-cylinder
ows to the
ebe her and moves the said supplemental slide-valve to d
passage, substantially as described.
the quick-t

page_text: 6. In the triple-valve device of a fluid pressure brake-mechanism, the combination
with the main slide-valve mechanism and its seat, of a normally closed quick-
action passage between the brake-pipe and outside air, opened only by movement
of said valve under an emergency reduction of brake-pipe pressure, a chamber in
said passage, ports in said seat, governed by the main slide-valve and communicating
respectively with the brake-cylinder passage and with the said chamber, a normally
open supplemental valve in said chamber movable, under pressure entering the
chamber from the brake-cylinder passage, to close the said quick-action passage,
the main slide-valve operating when at release and emergency positions only to
establish communication between said ports, substantially as and for the purpose
set forth.
11005
BOULT & WADE,
Agents for the Applicant.