lZ6~
The present invention relates generally to pneumatic rail
brake systems and more specifically to improved components for th.e
system.
The prior art brake systems were gener~lly standarized to
include an ABD or equivalant braking valve connected by conduits
to the brake pipe, auxuliary and emergency reservoirs and brake
cylinders. These brake valves would control all the brakes on the
trucks of a single car. If more than two trucks were to be
controlled by the brake valve, relay valves were included. These
systems include a substantial amount of conduits connecting the
elements of the brake system on each of the cars. The ABD and
- equivalant brake valves include the service application, emer~ency
application, release and accelerated release function. With the
development of non-conventional car designs, brake systems which
are adapations of the preexistlng brake systems were developed.
These and the conventional brake systems include an unnecessary
amount of conduits per car and unnecessarily large reservoirs.
Thus, it is an object of the present disclosure to provide a
simplified flu~d brake system for rail vehicles.
Another object of the present disclosureis to provide a
braking system which reduces the size of the auxiliary and
e~ergency reservoirs.
A further object of the-present aiSclosureis to eliminate
unnecessary piping and reduce the number of sources o~ fluid
leakage.
- 2 ~ ~,~
1Z69:12~D
Another object is to provide a group
of standard parts or modules which can ~e economically applied to
any type of freight car without special engineering, including
articulated cars having any number of trucks between couplers.
Here described is a triple valve assembly
having reduced auxiliary and
emergency reservoirs mounted directly thereon. ~he assembly is
connected only to the brake pipe and to the brake cylinder of one
truck and controls the interconnection between the brake pipe,
brake cylinder, auxiliary reservoir and emerqency reservoir to
produce charging of the reservoirs, service application and
emergency application of the brakes and release of air to the
brake cylinder. The unique triple valve, in response to the
venting of brake pipe which characterizes,an emergency brake
application, provides a sequential application of pressure to the
brake cylinder. Fir~t the auxiliary reservoir pressure is
equalized with that of the brake cylinder, followed by
disconnection of the auxiliary reservoir from an application of
the emergency reservoir to the brake cylinder. This sequential
operation allows increased brake cylinder pressure while allowing
redùction in the volume of the emergency reservoir used to
accomplish this pressure.
~ n both service and emergency applications, a variable flow
rate valve is co,nnected between the supply portion'of tne triple
valve and the brake cylinder to allow a high flow during the
initial application of the air to the brake cylinder with a
decreased flow rate during t~e second stage.
" lZ69~Z~i
The triple valve assembly is easily adaptable for receiving a
load responsive fixture. This fixture includes a first path for
connectirlg the supply to the brake cylinder and to a volume
reservoir and providing a predetermined portion of supply pressure
to the brake cylinder. A second path contrvlled by the load is
connected in parallel with the first path, and bypasses the
proportioning path and cuts off the volume reservoir for a loaded
sensed condition. ~ double acting piston is providea to
simultaneously open the bypass and close the dummy reservoir or
connect the dummy reservoir and close the bypass. The bypass is
also responsive to a brake released signal to bypass the
proportioning device during a ~rake release sequence.
A modulating valve is also provided independent of the triple
valve assemblies, which enhances brake pipe pressure reduction by
filiing a quick service volume wit-l fluid from the brake pipe for
a service signal, and sequentially venting a bulb volume to the
atmosphere and refills the bulb volume from the brake pipe as a
function of the magnitude of the service signal. The modulating
valve also charges the brake pipe with previously stored fluid so
as to enhance the rise of brake pipe pressure, hence release o'
- the brakes from a release reservoir in response to a release
' signal. The filling of the quick service volume occurs at a rate
- controlled as a function of the diffential pressure between the
release reservoir and the brake pipe. A quick action chamber is
included for providing accelerated response for filling the quick
1~6~126
service volume and venting the bulb volume. The quick action
chamber is vented after the accelerated initiation and has no
effect during further brake pipe pressure reduction activity.
More particularly, in accordance with the invention there is
provided, a modulating valve to be connected to a brake pipe
comprising:
brake pipe and atmosphere ports;
a quick service volume;
a bulb volume;
a release reservoir;
sensing means connected to said brake pipe port for sensing a
service signal, release signal and an emergency signal pressures
on said brake pipe port; and
valve means connected to said brake pipe port, atmosphere
port, said quick service volume, bulb volume, said release
reservoir and said sensing means for
(a) filling said quick service volume with fluid from said
brake pipe port for a service signal sensed by said sensing means;
(b) sequentially venting said bulb volume to said atmosphere
port and refilling said bulb volume from said brake pipe port as a
function of the magnitude of the service signal sensed by said
sensing means;
(c) charging said brake pipe port with fluid from said
release reservoir for a release signal sensed by said sensing
means.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described with
reference to the accompanying drawings wherein;
Figure 1 is a schematic perspective of a train brake system
made up of different types of cars.
Figure 2 is a perspective view of a truck mounted brake
incorporating a valve and reservoir.
Figure 3 is a perspective view of a modulation valve.
Figure 4 is a cross-section of a suppl~ valve.
Figure 5 is a cross-sectional view of a load fixture.
Figure 6 is a cross-sectional view of the modulation valve.
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~2~126
DETAILED DESCRIPTION OF THE DRAWINGS
A train 10 as illustrated in Figure 1 includes a plurality of
cars 12, 14, 16 and 18 of different styles for purpose of
illustration. Car 12 is a two-axle car, cars 14 and 16 are
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` 12691~6
articulated cars sharing a common axle and car 18 is a
conventional car having two axles per truck. A brake pipe 20
extends throughout the train 10. Each of the cars include a brake
system which for car 12 is a cingle axle brake 22 and for cars 14,
16 and 18 are double axle brake systems 24. Included at each
brake system are a truck 22 and 24 is a novel triple valve 100,
Also spread
throughout the train at approximately 75 foot intervals are
modulation valve systems 300. Thus, it can be seen that a braking
vaive is included at each truck irrespective of the truck and car
design.
The twin axle brake 24, as shown in Figure 2, consists of a
pair of brake beams 30, 32 and a single actuator 34 equipped with
double-acting slack adjuster 36 and cable 38 operated parking
brake, The a~ctuatar 34 is supported by, and lies along side, beam
30 and operates to spread a palr of bell cranks 40, whose ends are
attacned so as to drive the opposite brake beam 32 against its
wheels, The pivot points of the bell cranks 40 in the master bea~
30 react the equal and opposite force generated by this action
which pushes the master beam up against its wheels.
The 17~ total available stroke of the actuator is sufficient
to permit tbe beams to mount 2-1/2~ brake shoes and to operate
without adjustment through the life of these shoes and through a
full cycle of wheel wear.-
lZ6~126
The combined reservoir and triple valve 100, as shown inFigure 2, is designed to be mounted to the truck bolster and
connected with armored hoses 42 and 44 to both the brake actuator
and the brake pipe respectively. The triple valve is comprisea of
three die castings and includes: a simple triple valve to produce
service brake cylinder pressure, an emergency equalizing valve to
provide high brake cylinder pressure in emergency, and an inshot
valve to produce rapid filling of the actuator followed by a
controlled brake cylinder pressure rise, which should be
particularly important in an emergency brake application.
In connection with the triple valve portion, it should be
noted that no release insuring quick service or emergency brake
pipe related functions are included. When brake pipe pressure
reduces to zero, the triple valve reacts by raising the brake
cylinder pressure approximately 15~ higher than the value attained
at full service equalization. This will be described in detail
below with respect to Figure 4.
To provide cars having high gross-to-tare weight ratios with a
more even braking ratio over the entire load range, the triple
valve lOO brake equipment includes an optional empty load fixture
200, as snown in Figure 2. Because of the location of the basic
triple valve portion of the truck bolster, the empty load fixture
can be added by simply replacing a blanking plate with the
additional portion as shown -in the figure. The empty load portion
has a load arm 202, which can be connected to, or rest upon, the
1265~126
truck frame spring basket so as to detect empt~ or loaded
condition by the height of the bolster relative to this basket.
Since this dimension is unaffected by centerplate or side bearing
wear or truck swiveling, it provides a reliabli.e, repeatable
measure of spring deflection and, therefore, c.~r load.
In operation, the empty load fixtures operalte on the
proportioning principle, except that the dummy reservoir is on the
high pressure rather than the low pressure side of the
proportioning valve, resulting in its volume h~ing to be only 69
cu. in., which volume is easily enclosed in th~ empty load portion
itself.
The brake pipe modulation group 300, in Fi~re 3, consists of
an E-l modulation valve 302 and KM-2 vent valve 304 mounted to the
ends of a 10 x 20 release reservoir 3060 The ~nctions of this
valve are to provide all of the brake pipe st~lizing and
accelerating features of both the service and oemergency portions
of the present ABDW control valve. In particu.~r, the following
are carried out:
a) The quick service function detects bra~e pipe pressure
eeductions beyQnd a fixed amount and opens bra~e pipe to a quick
service volume so as to produce rapid serial t~ansmission of
.' service application and assure a minimum brake ,pipe reduction.
~ ) An accelerated application valve provi.~es continuous quick
service activity for brake pipe.reduction at a service rate beyond
quick service.
1269iZ6
.
c) An accelerated release valve provides <a dumpback to brake
pipe of the 1600 cu. in. release volume, any t~me brake p-pe
pressure rises more than a fixed amount, whet~er as a result of
service or emergency release. There is no accelerated release
after emergency because the 318 cu. in. of air stored in the two
actuators on a typical car would provide a ne~ligible improvement
in brake pipe release when compared with the ~256 cu. in.
available on a 10 x 12 cylinder at 8~ piston travel.
d) Rapid transmission of emergency brake application from any
cause is propagated solely by the KM-2 vent v~ve portion.
TRIPLE VALVE 100
The triple valve 100 as illustrated in Fi~re 4 includes three
devices: the rA~ triple valve 102, the ~B~ e~ergency equalizing
valve 104 and 2 brake cylinder inshot valve 1~l6.
Positions of the triple valve are release ~nd charging,
service, service lap and emergency. During ~h service and
emergency brake application, there is both a ~rst and second
stage of brake cylinder pressure development c~ntrolled by the
inshot valve lQ6. In emergency, a third staqe of development
increased brake cylinder pressure by approximæ~tely 15% above full
service.
Operation of the equipment foz each of the above positions is
as detailed below.
lZ69126
In the release and charging position, brake pipe air from the
brake pipe enters triple valve 102, through passage 14 to Chamber
A, moving the valve stem 121 downward and flows through Passage
11.2 to equalizing reset piston, Chamber C, a~d *hrough Passage 113
to the underside of the emergency reservoir ch~ging check 122.
Air flowing through this check 122 and Passage 114 charges the 150
cu. in. emergency reservoir and.flows by Passa~e 114a to the
emergency equalizing valve spool 123 where it ts blocked. Note
than when the triple valve piston 124 moves do~ward, Pilot Pin
125 raises the auxiliary reservoir charging che~k 126 from its
seat, permitting brake pipe air to flow from C~mber A through the
open charging check 126 and the hollow stem of ~he triple valve
piston 124 into Chamoer B, below the triple piston 1~4, from
whence it flows through Passage 116 into Chamb.e~ E to the lower
face of the emergency equalizing valve piston ~32 holding this
valve in its upper position. From chamber ~, alr flows through
Passage 115 to the emergency equalizing valve. sæool 123 and
simultaneously through Passage 115b to the 650- ~. in. auxiliary
reservoir.
With.both reservoirs charged, pressure acr~ss the triple valve
piston 124 will equalize; and it will move upw.a~d allowing the
charging check 126 to close cutting off commun~ation between the
brake pipe and auxiliary reservoir. This is t~e release lap ~
position of the triple valve 102.
-- 10 --
~26~3~L26
Note that with the emergency equalizing va~w~ 104 in its upper
position, air from Passage 115 passes upward thr~ugh the hollow
123a of stem 123 of this valve through Passage 1il7 to Chamber ~ of
the closed brake cylinder supply valve of th~ t~iple valve 102.
During a service application of brakes, brake pipe pressure
reduction in Chamber A will cause the triple valwe stem 121 to
move upward, unseating the supply valve 127 fro~ its outer seat
and connecting auxiliary reservoir pressure fro~ Chamber G past
the supply valve seat to Passage 118, through ~lch it flows to
the top of the open inshot valve check 128, th~gh this valve to
Chamber H, thence, through Passage 119 and the e~pty load blanking
plate 129 to brake cyiinder.
Brake cylinder air is also fed back throug~ ~assage ll9a to
Chamber F above the emergency equalizing valve ~4.
: - As brake cylinder pressure continues to bui~ up during a
second stage of a service or emergency applicat~on, it passes
through Chamber ~ of the open inshot valve chedk 128. When
sufficient air has flowed into the brake cylin~ to raise its
pressure to approximately 15 psi, the diaphragm ~iston 130 of
Cha~ber H moves down allowing the inshot valve c~eck 128 to
close. Further build up of brake cylinder press~re is under the
control of Choke Z. Thus, inshot valve 106 is a variable flow
rate valve allowing high flow during the initi~l stage of brake
pressure build-up and a low flow rate in the la~~ter stages.
"` 1~69126
As air flows from the auxiliary reservoir to the brake
cylinder, the pressure in Chamber ~, beneath the triple valve,
piston 124 falls until it nearly equals that of Brake Pipe in
Chamber A, at which point the valve stem 121 will move downward
and allow the supply valve 127 to close on its outer seat. This
will prevent the supply of further auxiliary reservoir air to
brake cylinder and, hence, terminate the reduc ion of pressure in
the auxilia~ry reservoir and Chamber B, placing the valve 127 in
service lap position.
With the supply valve 127 initially in the service lap
position, any increase in brake pipe pressure ~ill cause thé
pressure in chamber A to rise above Chamber B, ~hich will pull the
triple valve stem 121 down away from the supply valve 127, opening
the inner seat and permitting brake cylinder air to flow back
through the inshot check valve 128, opening it, hence, tnrough
Passage 118a and 118 past the open supply valve inner seat,
thence, through the hollow 131 of stem 12i of the triple valve 102
to atmosphere. Simultaneously with the above, brake ~ylinder
feedback pressure in Chamber F will reduce through Passage ll9a
along with brake cylinder.
Note that reduction of brake cylinder pressure in this manner
does not upset the balance of brake pipe pressure over auxiliary
reservoir, and the triple valve 102 remains in its release
position until brake-cylinder pressure reduces to zero.
- 12 -
lZ6~2~
Note also that if the brake pipe-pressure is only slightly
higher than auxiliary reservoir, the supply valve 127 inner seat
will be open; but because of the length of the auxiliary reservoir
charging check valve pllot pin 125, the charging check 126 will
remain on its seat preventing premature charging of the auxiliary
reservoir and, thus, assuring that no air will be trapped in the
brake cylinder. Only when a slightly greater pr~ssure exists in
the brake pipe than in auxiliary reservoir will the triple valve
stem 121 be forced downward sufficiently to open ~he charging
valve 126.
A modification to the triple valve could be m~de in which
further travel of the triple valve downward woul~ lead to a
retarded recharge position on cars near the head ~f the train.
~owever, the 650 cu. in. auxiliary reservoir take~ so little
charging air that this may not be necessary.
In an emergency brake applicatlon, brake pipe ~ressure is
suddenly reduced to zero. Triple valve 102 acti~ is iden~ical
with that descrlbed above under service brake application, and a
15 lb. inshot of air to the brake cylinder will ~e made prior to
closing of the inshot valve check 128, as in ser~ice From the
point of closing of the inshot valve check 128 u~il brake
cylinder pressure rises to within 2 psi of auxil-ary reservoir
pressure, brake cylinder pressure development is affected only by
the triple valve 102 and inshot valve check 128. Note, however,
that when brake pipe pressure is reduced to zero ln the emergency
_ 13 -
lZ6912~i
application, pressure in Chamber C beneath the eme gency
equalizing valve return piston 133 is also reduced ~o zero,
_ allowing the spring in Chamber D of this diaphragm piston 133 to
move it down so that it no longer holds up the eme~gency
equalizing valve stem 123. The emergency equalizing valve 123
will, however, be held up by the differential of a~xiliary
reservoir in Chamber E over brake cylinder pressure in Chamber F.
When brake cylinder pressure in Chamber F rises to within 2
psi of auxiliary reservoir pressure in Chamber E, ~he emergency
equallzing valve stem 123 will begin to move downward under the
influence of emergency spring 134 in Chamber J. C~amber J is
connected to atmosphere through Choke Y and the sm~ll hole 135
through the center of the equalizing valve stem 12~ to Chamber K
- beneath the spool 127, opening 137, and Chamber ~ aDove the
emergency equalizing valve return piston 133. Whe~ the emergency
equalizing valve stem 123 begins to move downward, supply valve
air in Passage 117 flows upward through Passage l~a; and at the
first motion of the emergency equalizing spool 123 downward,
Passage 117a is connected to Chamber J past the u~er land of the
emergency equalizing valve spool 123, causing auxillary reservoir
pressure present in Passage 117 to vent into Cham~er J where it
acts on the top of the emergency equalizing valve Sfem 123 urging
it rapidly downward. since Choke Y is much smaller than the
passage 117a admitting this air to Chamber J, presure developing
in Chamber J assures full motion of the emergency e~ualizing spool
123 downward until its motion is stopped by the ru~er seat 136 at
the bottom of Chamber K.
- 14 -
1~6912~
When the emergency equalizing valve rests on this seat 136,
communication through Choke Y to atmosphere through ~penings 137
is blocked and brake cylinder pressure is maintaineæ .in Chamber F,
where along with spring 134, it continues to hold t~e emergency
equalizing valve 123 downward against its lower seat 136.
Motion of the emergency equalizing valve stem 12~ to its lower
seat cuts off communication via Passage 115 of auxi~l~ry reservoir
to brake cylinder and the hollow 123a of the emerge~y equalizing
valve stem 123. In its lower position, this hollow stem 123a of
123 is connected to the emergency reservoir providi~ passage of
air to the brake cylinder from the emergency reserv~i~. Thus,
using emergency reservoir air only to increase brake ~yinder
pressure and not wasting it by needlessly increasins a-~xiliary
reservoir pressure as in earlier components with the ~mergency
equalizing valve in its lower position, emergency re~rvoir air
flows through the hollow 123a of stem 123 of the e~:~lizing valve
to Passage 117, thence, past the open supply valve t~ ~assage 118,
and through Choke z of the inshot valve check 128 t~ ~he brake
cylinder, addlng a third or high pressure phase to ~rake cylinder
pressure development.
With the brake applied in emergency, brake cyli~er pressure,
with an initial 70 psi brake pipe, would be 60 psi; auxiliary
reservoir pressur~ would be 50 psi (lower than brake cylinder~
because of the emergency equalizing valve). Thus, w~en brakes are
released, the brake pipe need only be restored to s~ething above
- 15 - .
- 126912~
50 psi to raise the pressure in Chamber A above the auxiliary
reservoir pressure in Chamber B. This reduced brake pipe pressure
requirement,..along.with_the,.dumpback o,f,air from the modulatlng
valve 300 should overcome the,need for the present accelerated
emergency release feature.
, As with service release, when the triple valve piston 124
moves down, it unseats its hollow spool 131 from the inner seat of
the supply valve 127, permitting brake cylinder alr to flow from
brake cylinder to Passage 119 back through the insho~ check valve
128, unseating this check 128, through Passages 11~ and 118 and
past the inner seat of the supp~y valve 127 to atmosDhere through
the hollow center 131 of the triple valve piston.
This action reduces brake cylinder pressure at a'rate
- independent of inshot choke z. As brake cylinder pressure
reduces, so does the pressure in Chamber F above the emergency
equalizing valve 132. At the same time this pressure is be~ng
reduced, pressure in Chamber C, beneath the emergency equalizing
valve return piston 133, is acting to force the emergency
equalizing valve 123 upward to its service position_ When the
brake cylinder.pressure in chamber F above the emergency
equalizing valve piston 132 drops to the point where the combined
' effort of auxiliary reservoir pressure in Chamber E and return
piston pressure in Chamber C are sufficient to urge it upward, it
will begin to move upward'and will cut off communication through
Passage 117a to Chamber J allowing Chamber J pressure to reduce to
- 16 -
.
691Z~i
atmosphe~e through Choke Y, assuring that once the emergency
equalizing valve 123 has started to move upward, this motion will
be continued_to its upper most stop and the release position.
Finally, when brake cylinder pressure drops below 15 psi, this
pressure acting in Chamber G will no longer be sufficient to keep
the inshot valve piston 130 down and will allow this piston 130 to
move up, aiding the back flow of air to keeping open the inshot
valve check 128 and assuring complete release of brake cylinder
air to the atmosphere.
Charging of the 650 cu. in. auxiliary reservo-r ~ill begin
when sufficient differential of brake pipe pressure over auxiliary
reservoir pressure exists to open the charging check 126 in the
triple valve stem, and charging of the 150 cu. in. e~ergency
reservoir will resume when auxiliary reservoir pressure has been
restored above 60 psi so that pressure can flow from ~assage 2
through Chamber C and the emergency reservoir charging check 122
to recharge this 150 cu. in. volume.
EMPTY LOAD FIXTURES 200
In the event that an empty load brake system 200 is requried,
the empty load blanking plate 129 shown in Figure 4 ~ay be removed
and the empty load device 200 shown diagrammatically in Figure 5
is mounted to it with the load arm 202~connected to the car as
shown in FigUre 2. This valve contains a simple ratioing valve
204, lock over piston 206, change over valve 208 and dummy volume
210, as shown in FigUre 5, and operates in the following manner:
6~12¢;
When a brake application is made, brake cylinder p~essure
enters from the triple valve in Passage 221 and flows. ~o Chamber A
on the left side of the..ratio valve. Simultaneously, air flows
through Passage 211a to the semi-circular area on top ~f the
change over valve key 208. In the event that the car ~s light,
the load arm 202 will be positioned downward; and bra~ cylinder
air will flow from Passage 211a past the key 208 to P~ssage 213,
thence to ~hamber C on the right hand side of the lock over piston
2Q6. Moving this piston 206 to the left requires onlyt 5 psi or
less; and in its left most position, the piston is de~nted by an
annular spring engaging a detent groove.
As air pressure continues to rise in the supply pressure in
Chamber A on the left hand side of the ratio valve 204 ~xerts less
force on the spool of this valve 204 than does the bra~e cylinder
pressure in Chamber B on its right hand side, forcinq ~e double
piston spool to the left against the ratio valve seat at a ratio
of 50, 60 or 70% of input pressure, as determined by t~
particular diaphragms used. As supply pressure from th~ triple
valve continues to rise, Chamber A pressure will build ~p, forcing
the spool to the right, allowing further passage of air through
the hollow spool to Chamber B causing it, again to close, with
- Chamber B pressure always at the desired ratio to Chamber A
pressure.
- 18 -
`" ~269126
Air also flows from Chamber A through Passage 211b and the
unseated dummy volume cut-off check valve 230 into Passage 212 and
the dummy volume 210. since the dummy volume 210 is only 69 cu.
in., this volume will accept the additional air supplied by the
triple valve and not needed by the brake cylinder at the lower
pressure of the ratio valve 204, thus, bringing about an e~ual
reduction in auxiliary reservoir pressure in response to brake
pipe pressure reduction whether the car is empty or loaded. Thus,
at final equalization in either service or emergency, the output
pressure of the triple valve in Passage 211 will be exactly the
same, whether the car is loaded or empty. Brake cylinder
pressure, however, whether service or emergency, will be 50, 60 or
70~ of that provlded by the triple valve as determined by the
ratio of Chamber A area to Chamber B area.
Note that during the above light, car operation, brake
cylinder air from Chamber B also flows through 114a to the face of
bypass check valve 232 but cannot open th-s valve because of the
higher supply pressure behind it, which holds it to its seat.
When brake cylinder pressure is released, air flows from
Chamber A out to the triple valve, through the triple valve~ and
to atmosphere causing the ratio valve 204 to close more tightly to
its seat. However, air from brake cylinder in Passage 214 can
flow through Chamber B, through Pas-sage 214a, and will unseat~the
bypass check 232 because of its differential over the now reduced
supply pressure in Passage 211c. Thus, during release, brake
-- 19 --
~Z6~1Zf~
c~linder pressure flows from brake cylinder into Passage 214,
through Chamber B, Passage 214a, past the bypass check ~alve 232,
unseating it, into Passage 211c, Passage 211b, Chamber A, and out
Passage 211 to the triple valve and exhaust.
If the car weighs heavy, the load arm 202 will be moved upward
to Position C; and Passage 211a will be connected through the
changeover valve key to Passage 215. Brake cylinder air will,
thus, enter Chamber D on the left side of the lock over piston
206, forcing it to the right, in which position it will be
detected, forcing the bypass check 232 off of its seat and
allowing the dummy volume cut-off check 230 to move to its seat.
As air pressure builds up in Passage 211 and Chamber A where,
again, it flows through the hollow piston rod of the rat~o valve
204 to Chamber B and the brake cylinder and, again, forces the
ratio va]ve to the left. ~owever, with the lock over piston 206
in its right hand position, air can flow from Chamber A through
Passages 211b and 211c and past the opened bypass check into
Passage 214, Chamber B, and out to the brake cylinder.
Since the dummy volume 212 is not desired cut in, as all air
suppiied by the triple valve in the loaded position must be passed
to the brake cylinder, the dummy volume cut-off check 23~, which
is permitted to move to its seat by the lock over piston 206, will
do so and prevent unnecessary loss of-air to the dummy ~olume-210.
- 2~ -
" ~Z69126
When brakes are released after an application with the empty
load fixtures in the loaded position, air flow out of the valve is
exactly the same as in the empty position with the exceptiOn that
brake cylinder pressure does not have to move the bypass ~heck 232
off of its seat as it is held open by the lock over piston 206 in
any case.
E--1 BRAKE PIPE MODULATION VALVE 302
The purpose of the E-l brake pipe modulating valve 3~2 shown
in Figure 3 and diagrammatically in Figure 6, is to provide quick
service propagation of an initial service application and to
provide a continuous quick service function. A third purpoSe is
to control the storage and release back to brake pipe of air in a
release volume so as to provide accelerated release of brakes
- -after both service and emergency brake applications.
The only connection to tbe E-l brake pipe modulating valve 302
is to the brake pipe and the augmentation of brake pipe pressure
change it provides will be comparable to those in the AB, ABD and
ABDW type control valves.
When charging this valve 302, air flows initially from brake
pipe by passage 311 to the underside of accelerated release valve
piston 320, Chamber A, thence through Passage 316 to Chamber C on
the underside of accelerated application pilot valve piston 322.
Air from Chamber C flows through Quick Action Chamber Charging
Choke Y and Passage 317 to the ~uick action chamber 308, and
- ~2691Z~
Passage 317a to the back of-the accelerated application pilot
valve check valve 324. Air flowing through Choke Y is at qUiCk
action chamber pressure and is communicated via Passage 317b to
Chamber D, above the accelerated application pilot valve piston
322 and Chamber B, above the accelerated release valve piSton 320.
Note that brake pipe pressure in Passage 316 also flows
through Passage 316a to Choke z and to the face of release
reservoir c~ontrol check 326 through Passage 316b. Brake pipe air
flows through Choke z into Passage 318 and the underside o~ the
accelerated release check 328, thence past this cbeck 328 into
Passage 319 whence it charges t~e release reservoir and through
Passage 319a to Chamber F above the quick service llmiting ~alve
piston 330.
With the equipment fully charged, pipe pressure may be reduced
to initate a brake application. When such a reduction is begun
simultaneous reduction-of pressure in Chambers A, C and E occurs.
No motion of the quick service limiting valve 332 will occur
because it is held up by a 3 psi differential spring 334 in
Chamber G. The accelerated release valve piston 320 will
initially be resting on the stabilizing spring cage 336, having
permitted the accelerated release check 328 to close at the
termination of release reservoir 306 charging. The accelerated
release valve piston 320-will not move down until the brake plpe
pressure drops-about 1/2 psi and will not move down until the
stabilizing spring has been overcome. When this occurs, the
- 22 -
126~
accelerated release valve diaphragm piston 320 will move do~n
opening the quick service check valve 338. ~hen the quick service
check valve 338 is moved off its seat, brake pipe air will ~low to
the quick service volume 340; and because of~the proximity ~f the
quick service check 338 to Chamber A, this flow will cause a
further downward motion of the accelerated release valve piston
320, thus, assuring that the quick service check 338 will o?en
wide, permitting brake pipe pressure to flow from brake p-pe
through Passage 311, Chamber A, Passage 312, past the open guick
service check 338 to the quick service limiting valve spool 332,
hence, into the quick service volume 340.
Initial flow of air will be rapid enough to propagate this
quick service action to the next ca~ and will terminate when a 3
psi differential of release reservoir pressure over brake p pe
pressure is established, which differential will move the quick
service limiting valve spool 332 down cutting off further
communication with brake p-pe through the quick service check 338.
At this same time, accelerated application p-lot valve piston
322 also moves down forcing its check 324 from its seat and
perm tting quick action chamber 308 air to flow from Pass2ge 317a
past the open check valve 324 to atmosphere through Choke U, while
.' subjecting the inner area of the accelerated application valve
d-aphragm 342 to the pressure backed up by Choke V. - - -
If this backed up pressure is sufficient, it will cause the
accelerated application diaphragm 342 to move downward from its
12691Z~
seat exposing the larger outer area and permitting the upper
accelerated application check valve to seat 344, cutting off
communication between brake pipe in Passage 312 and the already
charged bulb volume 346. As ].ong as the accelerated application
pilot valve 322 is down, permitting quick action chamber 3~8 air
to flow to atmosphere, the accelerated application valve p ston
342 will be held down by air acting over its full upper diaphragm
face, and will drain the bulb volume 346 through Passage 314 and
its lower check valve 348. When quick action chamber 308 pressure
reduction exceeds that of the brake pipe, the accelerated
application pilot valve piston 322 will rise, allowing its check
324 to close and cut off the supply of quick action chamber 308
air to the accelerated application valve piston 342 ~hich will
allow its upper chambers to drain through Chokes U and T. This
action will allow the accelerated application valve piston 342 to
move upward, returning its lower check 348 to its seat to prevent
further draining of the bulb volume 346 and reopening its upper
check 344, thus, reconnecting the drained bulb volume 346 to brake
pipe causing a controlled volume of air to be withdrawn from it,
thus, causing a further reduction of brake pipe pressure by
allowing Passage 312 to communicate past the upper check 344 to
Passage 313 and through Choke V wi~h the now drained bulb volume
346. After quick service activity has terminated, any time brake
pipe pressure is reduced, the accelerated application pilot valve
piston 324 will, again, move down triggering this sequence o~
events much the same way the accelerated application valve
operates on the present A8DW emergency AAV portion.
- 24 -
lZ6~1Z6
Whenever ~rake pipe pressure rises above quick action chamber
pressure in Chamber B by more than a predetermined amount,
accelerated release valve piston 320 will be moved upward and
unseat the accelerated release check 328. This action will dump
accelerated release volume 306 back to brake pipe, aidins in the
restoration of brake plpe pressure by way of Passage 319, past the
open accelerated release check 328, Passage 318 and 318a, through
the release control check 326 bypassing Choke z, into Passage 316a
and 316b, Chamber A, and out Passage 311 to the brake pipe. At
the same time, the motion of the accelerated release valve piston
320 upward allows the quick service check 338 to seat, preventing
the exhaustior. of brake pipe air when the quick service limlting
valve 332 returns to its upper position. As brake pipe pressure
recharges and accelerated release reservoir air pressure
decreases, the differential of Chamber A over Chamber B in the
accelerated release valve will be decreased; and when brake pipe
pressure is less than 5 psi, higher than accelerated release check
328 pressure, the accelerated release check 328 spring will return
this check valve 328 to its seat and the E-l brake pipe modulating
valve 302 will.be returned to its fully charged posltion. Above
this pressure, brake pipe pressure can only be supplied from the
locomotive; and when a further 3 psi has been bullt up in the
brake pipe, its pressure will be higher than accelerated release
reservoir pressure and accelerated release reservoir 306 recharge
will begin through Choke Z and the accelerated release reservoir
charging check 328.
- 25 -
12~91~6
From the preceding description of the preferred embodiments,
it is evident that the desired objects are attained in that
reduced size reservoirs are mounted directly to the triple valve
which are mounted on each truck. The accelerated application and
release functions are separate from the triple valve and are
distributed throughout the train.
Although the invention has been described and illustrated in
detail, it is to be clearly understood that the same is by way of
illustration and example only and is not to be taken by way of
limitation. The spirit and scope of the invention are to be
limited only by the terms of the appended claims.
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