Note: Descriptions are shown in the official language in which they were submitted.
~ 1~380~L
BACKGROUND OF THE I~VENTION
Field of the Invention:
~ This invention relates to a relay valve for use in an
¦ air brake system wherein brake actuators are operated by fluid
pressure~
This Application is a dilision of Canadian Patenl
~pplication Serial No. 233,078, fiLed August 7, 1975
¦ Description of the Prior Art:
In air brake systems, especially in tractor-
trailer combinations, a problem exists in that air
pressure applied at the tractor portion must actuate
the trailer brakes which are physically located substan-
tial distances from the tractor. ~s a result, time delays
I exist between the air brake ~ppli.cat:Lon at the -tractor and
air bra]se actuatio~ at the trailer. To reduce such time
delays, valves and systems were devised whereby an air
supply was provided in proximity to the trailer brakes
and a relay valve was provided adjacent that air supply.
' In àddition, since an electrical impulse can move between
two points faster than an impulse moved by air pressure,
j electrical means were provided to actuate the relay valve
for releasing air pressure to actuate the trailer brakes in-
asmuch as electrical signals could actuate the trailer brakes
almost simultaneously with application of the brakes at
the tractor thus avoiding the previously known time delays.
Such systems are of the type shown and described in U.S.
Patents 3,7~7,992 and 3,796,~68. Uneortunately, the systems
of the prior art are not compatible with skid control systems
un:less a novel relay valve is provided in the sys-tem.
-- 2 --
~3~
SUMMARY OF THE INVENTION
According to a broad aspect of the present
invention there is provided a relay va~lve for use in an
air brake system wherein brake actuators are operated by
fluid pressure. The valve comprises first port means in
the valve for receiving a first impulse of fluid pressure
from a first source. A second port means in khe valve is
provided for receiving a second impulse of fluid pressure
from a second source. A first solenoid means normally
opening in the first port permits the first tmpulse o~
pressure to enter tho valve and a second solonoid moan~
normall~ closing the second port and oporably connected
for permitting the second impulse of pressure to enter
the valve simultaneously with the first impulse.
, ~, .A\ . .. , `
~3~
Other advantages and novel features of the
invention will become apparent from the following
detailed description of the invention when considered
in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings wherein Like parts are markeA
¦ alike:
¦ FIG. 1 is a diagrammatic illustration of the
system of this invention'
j 10 FIG. 2 is a partially cutaway side elevation of
¦ the novel relay valve of this invention,
FIG. 2a :is an exploded part:ial s:Lde elevation
oE the lower hous:ing o~ FIG. 2,
FIG. 3 :is a cutaway p:Lan view oE the novcl
relay valve of this invention taken along line 3-3 of
FIG. 2,
FIG. 4 is a diagrammatic illustration of the
first logic circuit of this invention' and
FIG. 5 is a graphical illustration of the
deadband effect included in -this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates an electro-pneumatic air
brake system generally designated 10 which comprises a
first portion 12 mounted on the tractor o-f a tractor-
¦ trailer combination and a second portion 14 mounted on
the trailer. Electro-pneumatic air brake systems are
- 4
~1~380~
w911 known and generally include various interconnected
electrical and fluid operated components including
contained sources of fluid, such as air, under pressure.
Tractor portion 12 ineludes first or application
valve 16 having a foot pedal ~4 to be actuated or
d~pressed by the vehicle oper~.tcr. Air is contai.ned
under pressure in first reservoir 18. Conduit 20
interconnects reservoir 18 and valve 16. Also, conduit
' 28 interconnects reservoir 18 and tractor relay valve
l'.~ 10 26. Conduit 24.guides control al.r to relay valve 26 to
actuate valve 26 to apply air to the rear tractor brakes
,
and cvndult 30 guides air from relay valve 26 ~o ~ha
rear tractor brakes ag shown ln the drawlng, Conduit 23
delivers air from relay valve 26 to the front tractor
brakes. Conduit 38 interconnects first reservoir 18
~ .with second or trailer reservoir 36 so that the tractor
=~ and trailer fluid pressure systems can reach an equilib-
: rium pressure. Conduit 22 interconnects first or appli-
: cation valve 16:with first port 72 of second or trailer
relay valve 40. First transducer 42 is provided along
conduit 22 adjacent valve 16 to sense pressure in that
conduit and convert the pressure sensed into an electri-
cal signal for sending that signal along el~ctrical
. ~ connector 44 to first logic means or electronic control
46 of trailer portion 14. Air conduits 22, 38 are
.l continued at the tractor-trailer interface by well.known
gladhands connectors 34, 32, respectively.
Trailer portion 14 includas relay valve 40. In
addition to air supplied to first port 72 of rel.ay valve
40 from first reservoir 18 of tractor portion 12, second
I _ 5 _
~(i38~
reservoir 36 supplies air to second port 74 of relay
valve 40 via conduit 70. Also, air may be supplied from
r~servoir 36 to another portion of relay valve 40 via
conduit 68 and ultimataly to some of the brake actuators
such as the rear trailer brakes via conduit 48, Fir~t
logic means ~i6 is electrically c^~ îected to a first
solcnoid adjacent first port 72 o~ relay valve 40 via
I electrical connsctor 62 and to a second solenoid adjacent
second port 74 of relay valve 40 via electrical connector
10 60, Second transducer 50 is provided along conduit 48
adjacent valve 40 to sense pressure in that conduit and
conv0rt the pxessur0 sensed lnto an elactrlcal signal
~or sendlng ~hat signal to ~irs~ lo~lc mean~ 46 vla
electrical connector 52. Second or skid control logic
means 54, well known, receives input sensor signals from
the vehicle wheels via electrical connector 66 to deter-
I mine impending skid conditions. A slcid control output
logic signal is sent to first logic means 46 via electri-
cal connector 56 and to the electrical connector 62
~ 20 leading to the first sol~noid via electrical connector
: FIG~ 2 generally illustrates relay valve 40
having an upper housing portion 102 and a lower housing
portion 204. Each housing portion is pre~erably formed
by casting a suitable metal ~or Elnishing as by machining
or the like, although other sui.table casting or molding
materials ar.e contemplated.
Upper housing portion 102 includes generally
annular portion 10~ having an outer annular peripheral
surface lOSa and an inner annular bore 108b extending
.. , ~
.' 6 -
~(~38~
inwardly from first annular end 110 and terminating at
inner surface 112a of annular endwall 112. First end
110 includes groove 110a for accommodating sealing 0 ring
114. Outer surface 108a extends upwardly from end 110
and terminates at and extends into outer surface 112b of
endwall 112. ~nnular bore 106 is centrally located in
endwall 112 and includes annular lip 116 having inner
and outer annular surfaces 116a and 116b respectively.
Vertical passageways 118 and 120 are formed in endwall
112 and extend therethrough from inner surface 112a
continuing upwardly into extended portions 122, 124
respectively integratedly formed with upper portion 102.
In FIG. 3, passageways 118, 120 terminake at
openinys 123, 125, respectively. Transverse or horizontal
passageways 126, 128, respectively interconnect openings
123, 125 with vertical passageways 130, 132 which, as
shown in FIG. 2, terminate in enlarged openings or ports
72, 74, respectively, adapted for being threadedly secured
to appropriate high pressure fluid connectors to res-
pectively accommodate fluid conduits 22 and 70.
Returning to FIG. 3, well known solenoids 134,136 of the type generally shown and described in U. S.
application Serial Number 369,966 filed June 14, 1973 now
U S. Patent Number 3,854,501, entitled "Antilock Brake
System and Control Valve Therefor" issued on December 17,
1974 to John A, Machek and assigned to the ass.i~nee o~ th'is
invention, are mounted in side by side annular openings 101,
103, respectively, formed in upper portion 102 and having
centroidal axes transverse to the centroidal axis of
annular bore 106. Openin~s 101, 103 extend inwardly from
~Q380~1
first end 105 and terminate at endwalls 107, 109,
respectively. Threaded recesses 142, 144 are formed in
endwalls 107, 109, respectivaly. Threaded mounting
portions 138, 140 of solenoids 134, 136, respectively,
S are secured into correspondingLy threaded recesses 142~
144. Threaded recesses 142, 1~4 cLi~ integratedly formed
with openings 123, 125 respectively for accommodating
plunger sealing portions 146, 148 of solenoids 134, 136,
respectively. Electrical connector 143 is appropriately
mounted in housing portion 102 ~or lnterconnecting
~_~ electrical power supplled to receptacle 145 with the
conductlve portions or coi:Ls 1~9 whlch surround ,~xlally
reciprocable arm~tur~s 156 o~ the well known solenoids
via conductive ~lux plate 111. Coils 149 are insulatedly
mounted in housing portion 102 by appropriate nonconduc-
tive insulators 147 in the well known manner. Also,
plunger shaft portions 150, 152 of solenoids 134, 136,
respect-Lvely are provided to interconnect armatures 156
with sealing portions 146, 148 for sealing engagement
with seating areas or lands 123a, 125a, respectively,
formed at the intersecting portions of openings 123, 125
and horizontal passageways 126, 128, respectively.
Exhaust passage 158 is formed iTI firs-t extended portion
122 and includes relativaly large passage portion 160
.25 integratedly and coaxially formed with relativaly small
passage portion 162 so that exhaust passage 158 inter-
connects plunger passage 164 with annular opening 101.
In this manner, first sealing sur~ace lll6a o~ solenoJd
sealing portion 146 may seat against lalld 138a formed on
threaded mounting portion 138 of first solenoid 134 to
- 8 -
~L0 3~ ~
interrupt ~luid communication between plunger passageway
154 and opening 123 when in a first, or non-actuated
position, or in the alternative, second sealing surface
146b of solenoid sealing portion 146 may seat against
land 123a to interrupt fluid cotnmunication be~ween
horixontal passageway 126 and ope~ 123 when in a
second or actuated position, Thus, plunger shaft 150 is
normally biased by spring 166 so that second sealing
curface 146b is normally out of sealing engagement with
land 123a and ~luld communication between passage 126 and
opening 123 is normally open, Plunger 152 extends through
plunger passage 168 o~ threaded mountill~ portion 1~0 o~
second solenoicl 136 mounted in almular opening 103.
Sealing portion 148 is mounted on plunger sha~t 152 and
includes first sealing surlace 148a for sealing engagement
with seating area 125a to limit flui.d communication
between horizontal passageway 128 and opening 125 when
in a first or non-actuated position, or in the alternative,
second sealing surface 148b of solenoid sealing portion
148 ~ay seat against land 140a of threaded mounting
portion 140 to open fluid communication between horizontal
passageway 128 and openi.ng 125 when in a second or
actuated position. Thus plunger sha~t 152 is normally
biased by spring 170 so that first sealing surface 148a
is normally in sealing engagement with seating area or
land 125a and fluid communication between passa~e 128
and opening 125 is normally closed. Nonconductive closure
member 154 including receptacle 145 seats in recess 105a
ormed in end 105 of upper portion 102 to position flux
plate 111 in recess 105a against displacement, the closure -
. _ 9 _
~L~3~ Q~
mamber being sacured to the housing by some suitable means.
Lower housing 204, FIG. 2, is generally annular
and includes upper surface 202 including a centrally
located aperture 206 therein .for co~xial disposition with
bore 106 of upper housing 102, Recess 208 is ~ormed a~
the intersaction o~ outer annular n~riphery 214 and sur- .
face 202 for accommodating l~wer annular end 110 o upper
housing 102. Also, recess 210 is formed in upper surface
202 and extends downwardly into housing 204, Threaded
outlet or port 212 is formed in outer per-Lph~ry 214 for
accommodating an appropriate ~lxture ~or conduct~ng ~luld
under pressure rom r~J.ay valve l~o to th~ v~h~.cl.e brake~
via condui.t 48, Ou~ 212 ~x~ncls inwardly :Lnto low~r
housing 204 and intersects rocess 210, Threaded inlet
or port 216 is formed in ou~er periphery 214 Eor accommo-
dating an appropriate ixture for conducting ~luid under
pressure from fl.uid pressure source 36 to rela~ valve 40
via conduit 68~
Stepped annular bore 218, FIG. 2a, is formed in
l~wer housing 204 and extends from lc~er surface 220
toward its intersection with aperture 206 in upper surface
202 to accommodate exhaust port or passageway 219 through
lower housing 204 coincidental with tha centroidal axis
thereof, Bore 218 includes first portion 218a intersect-
ing with lower surEace 220 and extellding inwardly ~o
intersect with snap ring groove 218b, Retainer groove
218c of bore 218 is adjacent snap ring groove 218b and
second portion 218d extends inwardly ~rom retainer groove
218c to its intersection with third bore portion 218e
forming shoulder 221, Annular saating portion 222 is
- 10 -
~ 0 3 ~
ormed at the on shoulder 224 intermediate of bore portion
Z18e and aperture 206. First annular insert 226 is
preferably of metal and includes xetaining surface 228,
inner annular surface 230 including inner groov~ 232,
outer annular surface 234 lncluding outer groove 236, ,and
upper suraco 238 axially oppos;te ~etaining surace 228
and interposed between inner and outer grooves 232, 236,
Second annular insort 240 is preerably of metal and ''
includes lower suraco 242 and axially opposed upper land
or sur~ace 244, inner annular suraca 246 and outer
annular surace 248. ~nnular pi9ton or plungar 250 ls
preerably oE matal and is genQrally ~ubular includ-lng
lower end 252 and upp~r El~n~ad ancl 25l~ Int~rm~diate
tubular or cylindrical portion 256 interconnects upper
and lower ends 254, 252, respectively and includes
outer periphery 258 and inner periph~ry ~60. Uppcr
flanged end 254 includes resilient seal member 262 held
in place by metal retainer 259 forming a lower spring
seating surface 259a of flanged end 254. Piston 250 may
be inserted into bore 218 so that seal me~ber 262 engages
annular seating portion 222. Second insert 240 is placed
in bore 218 ~o that inner annular surface 246 engages
outer periphery 258 of piston 250 and outer annular
surface 248 engages bore portiorl 218d. Second insert 240
is axialLy retained by shoulder 221 ln~ermedia~e o~ bore
portions 218d and 218e~ First insert 226 is placed in
bore 218 so that upper surEace 238 engages lower surface
2~2 of second lnsert 2~0, outer peripl~ery 23l~ engage~
bore portion 218d and inner periphery 230 engages outer
periphery 258 of piston 250. Resilient sealing 0 rin~s
~3800~ -
261, 263 are placed in inner and outer annular grooves
232, 236, respec~ively, R~tainer 264 is snapped into
retain~ groove 218c to abut retainer surface 228 of
first insert 226 and snap ring 266 is snapped into snap
ring groove 218b to abut and .secure retainer 264 in place.
Sprlng 268 is disposed between ~pring s~ating sur~ace
259a and upper land 244 to normally urge sealing member
262 into sealing engagement with annular seating portion
222,
Annular piston 306 is preferably of metal and
~_~ includes upp~r surface 308 including extended por~n 310
centrally loca~ed and provlded to slLdably ang~ inner
surface 116a of upper housing 102, O ring groove 312 is
provided in annular periphery 310a ~or acco~nodating
resilient 0 ri.ng 314 in sealing and sliding en~agement
¦ . with surface 116a, Outer annular peripheral sur~ace
316 of piston 306 includes O ring groove 318 for
accommodating resilient O ring 320 in sealing and sliding
engagqment with inner surface 108b of upper housing por-
¦ 20 tion 102. Lower surface 322 of piston 306 includes
e xtended portion 324 axia-Lly opposed to extended portion
310, Extended port`ion 324 terminates at annular seat 326
engageable with sealing portion 262 of piston 250.
Compression spring 328 is disposed between sur~ace 322
of piston 306 and upper sur~ace 202 oE lower houslng 204
for urging piston 306 upwardly away from lower housing
204 and.toward housing 102 so that annular seat 326 do~s
no~ normally engage seal~262 o~ piStOII 250.
Main piston chamber 506 is ormed by inner surface
112a of upper housing 102, upper surEace 202 o Lower
, .
- 12 -
housing 204 and i~ar annulax bore 108b of upper housing
102. Piston 306 sealingly slidably engages inner annular
bore 108b via sealing ring 320 to separate main chamber
506 into upper chamber portion 508 and lower chamber
portion 510, The upper chamb~r is formed by inner sur.
face 112a, upper sur~aca 308 of n; ~t~n 306 and inner
annular bore 108b. The lower chamber is formed by lower
sur~ace 322 of piston 306, upper surface 202 and inner
annular bore 108b~
FIG, 4 includes the logic circuitry o: first
logic means 46 whi.ch is the electronic control connectad
to roceive ~irs~ and s~cond signn~.s Ero~n ~:Lrst nnd sacond
transducors 42, 50, resp~ctlvaly, Inasmuch as first
sensor or transducer 42 senses fluid prassure in condui~
22 and produces a ~irst signal proportional ther~to and
inasmuch as second sensor or transducer 50 senses ~luid
pressurc in conduit 48 and producas a seconcl signal
proportional thereto, the first logic means 46 is, capable
of discriminately controlling communication of a second
-
pressure impulse to the trailer brakes (not shown)
dependent upon impulse communication of a first.pressure
from ~irst valve 16 to second valve 40. It can be seen
from the logic system o FIG. 4 that ~or example where
the system pressure is within a range of 0-100 pounds
2S per 9quare inch (psi) th~ transducars 42? 50 may produca
a proportional signal within the ringe of 0-10 millivolts
(mv). Thus ? in the application mode, for example,
wherein a pressure o~5~ psi is procluced a~ application
valve 16 and into conduit 22, a proportional signal o~
S mv will ba sent from transducer 42 to logic means 46
- 13 -
~ ~ 3 ~
via connection 44~ This signal enters the logic means
at line 44 and is sent to inverter 462 via line 402 and
also sent to adder 408 via lines 404, 406 and to compara-
tor 412 via lines 404, 410. Thus, inverter 462, aclder
408 and comparator 412 each raceive a 5 mv signal frol,l
transducar 42. The 5 mv signal rec~ived by inve~ter 462
is inverted to a minus (~) 5 mv signal and sent to adder
420 via line 418. At this point there is no significant
pressure sensed at transducer 50 so that a zoro ~0) mv
signal is reallzed by logic means 46 relative to trans-
ducer 50. Th:Ls 0 mv si~nal ent~rs ~he loglc means at
line 52 and is sent to inverter 436 v:i.a line ll2~ and
also sent to acldar 420 vi.~ lines 424, l~28 ancl to
comparator ~30 via lines 424, 426. Thus, inverter 436,
adder 420 and comparator ~30 each receive a 0 mv signal
from transducer 50, Tha 0 mv si~nal received by inverter
436 is inverted to a minus (-) 0 mv signal and sent to
adder 408 via line 438.
At this point adder 408 is receiving a 5 mv input
~20 signal from transducer 42 and a -0 mv input signal from
transducer 50 via inverter 436. The adder, as is well
j known, will algebraically add the values of these inputs
! and produce a resultant output signal which, in this case,
, is a 5 mv signal which is sent to comparator 442 via line
¦25 440. Similarly, adcler 420 i5 receiving a ~5 mv input
signal from transducer 42 via inv~rter 462 and a 0 mv
input signal from transducer 50, ~dder 420, as is well
known, will algabraically acld the values of these ir;puts
and produce a resultant output signal which, in this case,
i5 a -5 mv signal which i9 sent to comparator 454 via
~ ~ 3~0
line 452.
Comparators, as it i5 w~ll known, can receive
various signals and compare them to produce either a
signal of some value (e.g. l) or no signal (e.g. 0).
Comparator 412 is provided to receive a predet~rmined
signal from an ~xtcrnal pow~r ~OUL~C~, e.g. a predetermined
signal of .5 mv to simulate a pressure sensed of 5 psi.
Comparator 442 is provided to receive a pre~etermined
signal ~rom an external power source, e.g. a predetermined
s ignal o~ -~25 mv to simulate a pressure sensed o~ -2.5
psi. SimiLarly, comparators 432 and 454 are receiving
signals o~ ~5 mv and -~25 MV, raspectivcly. Thus, com-
parator 412 is re~civ~lng signals o 5 mv and .5 mv~ com-
parator 442 is receiving signals of 5 mv and - 25 mv, com-
parator 430 is receiving signals of 5 mv and 0 mv and
comparator 454 is receiving signals of -5 mv and -.25 mv.
In logic means 46, comparator 412 is provided to produce
a signal of value (eOg. a 1 signal) if the value of the
signal it receives via line 410 is greater than the value
2V of the signal it re~eives via line 414, and to produce no
signal (e.g. a 0 signal) if the value of the signal it
receives via line 414 is greater than the value of the
signal it r~ceives from line 410 In this case, comparator
412 reccivas the signal of greater value from line 410 and
thus produces a 1 signal communicated to "and" gate 448
via line 416 Comparator 442 is provided to produce a 1
signal if the value oE the signal it receives via line 440
is greater than the value of thc signal it receives via
line 444, and to produce a 0 signal if th~ value of the
signal it receives via line 444 is greater than the value
- 15 -
~3~0Q~
of the signal it recsives from line 440c In this case
comparator 442 receives the signal of greater value from
line 440 and thus produces a l signal communicated to
"and" gate 448 via line 446. Comparator 430 is provided
to produce a l signal if the value of ~he signal it
receives via line 426 is greater ~ha~ the value of the
signal it recelves via line 432 and to produce a 0 signal
if the value of the signal it receives via line 432 is
1 greater than tho valu~ of the signal it receives via line
426. In thl9 case comparator 430 receives the signal of
greater value from line 432 and thus produces a 0 sign~l
, communl.cated to "ancl" gate 460 vln lin~ 43~ omparator
454 i9 provLdcd ~o produc~ a l signal i~ the v~lua oL- the
signal it receives via line 452 is greater than the value
t lS of the signal it receives via line 456 and to produce a
0 signal if the value oi the signal it receives via line
456 is greater than the value of the signal it rec~ives
from line 452. In this case comparator 454 receives tha
signal of greater value from line 456 and thus produces
j 20 a 0 signal communicated to "and" gate 460 via line 458.
'IAnd" gates, as it ls well known, can receive
both a l signal and a 0 signal to produce either a result-
ant l signal or 0 signal. "And" gates 448, 460 are
3 provided to produce a l signal when each signal it receives
is a l signal and to produce a 0 signal when any signal
, it receives is a 0 signal, At this point "and" gate 448
! is receiving a l signal from comparator 442 and a l signalfrom comparator 4l2. Thus, gate 448 produces a l signal,
"~nd" gate 460 is receiving a 0 sigllal fro1n comparators
430, 454, Thus, gate 460 produces a 0 signaL.
- 16 -
,j
.
1 ~ 3 ~
"Nor" gates, as it is wcll known, can receive a
0 signal and change it to a 1 signal, and in the alterna-
tive c~n receivH a 1 signal and.change it to a 0 signal.
The 1 signal ~roduced at "and" gate 4~8 is sent to "and"
S gate 474 via line 450, 478 an-l to "nor" gate 482 via li~qs
450, l~76 "Nor" gate 482 converts the 1 signal received
rom "and" gate 448 to a 0 signal which is sent to "and"
gate 486 via line 484. The 0 signal produced at "and"
gate 460 is sent to "and" gate 486 via lines 464, 466 and
to "nor" gate 470 via lines 46~, 468. "Nor" gate 470
converts the 0 signal received ~rom "and" gat~ 460 to a
1 sign~l which :is sent to "and" gclte 474 via line 472.
Thus "and" gata 47l~ rccelv~s a l signaL .Erom "mld" gate
448 and a 1 signal roln "nor" gate 470, whereas "and"
gate 486 receives a 0 signal ~rom "and" gate 460 and a 0
signal ~ro~ "nor" gate 482. ~s previously stated, the
"and" gates produce a 1 signal if they receive only 1
signals and produce a 0 signal if they receive any 0
signal. Thus, it can be seen that "and" gate 474 will
I ~
produce a 1 signal along line 480, and "and" gate 486 will
produce a 0 signal along li.ne 4~8. Any signal from "and"
gate 474 is sent along line ~80 to a power amplifier 481
and then is transmitted along lin~ 60 to second solenoid
¦ 136 which is normally closed. ~ly signal rom "and" gate
¦ 25 486 is sent along line 438 to a power ampll.Eier 489 and
then is transmitted along line 62 to Eirst solenoid 134
which is normal.ly open.
Still reerring to FIG. 4~ the above-described
logic means 46 beillg similar to those well known in
tractor-trailer fluid psessure eel-y systems, a novel
17
.. . . .
;:
1~38~
dimension is contemplated by this invention due to the
coupling of the first lo~ic means 46 with a known skid
control logic means 54 via line 56 so that tractor-
trailer fluid pressure relay systems may be adapted to
meet skid control requirements. S~id control logic means
54 may be o~ the type shown and described in United States
Patent Number 3,827,760 to Joseph ~. Fleagle, issued on
August 6, 1974 on application Serial Number 218,378 filed
January 17, 1972 and entitled "Wheel Slip Control System
For Automotive Vehicles And The Like", United States Patent
Number 3,842,355 to Joseph E. Fleagle, issued on October
15, 1974 on application Serial Number 3~0,735 ~iled March
13, 1973 and entitled "Signal Processing ~ircuit For Wheel
Slip Control Systems", a division of the above-mentioned
United States Patent Number 3,827,760, United States
Patent Number 3,833,268 to Joseph E. Fleagle, issued on
September 3, 1974 on application Serial Number 223,579
filed March 10, 1972 and entitled "Wheel Slip Control
System For Automotive Vehicles And The Like", and United
States Patent Number 3,840,816 to Joseph E. Flea~le issued
on October 8, 1974 on application Serial Number 340,915
filed March 13, 1973 and entitled "Wheel Speed Signal
Processing Circuit For Wheel Slip Control Systems", a
division of the above~mentioned United States Patent
Number 3,833,268, each of the above-mentioned patents
bein~ assigned to the Assignee of the present invention.
- 18 -
~3~Q~
Also, line 54 interconnects skid control logic 54 and
line 62 for direct electrical communication between the
skid control logic and normally open solenoid 134. Thus,
from the foregoing it can be seen that when impending
s~id conditions are sensed and transmitted to skid control
loyic means $4 via line 66, that logic means can 3end a
siynal to "nor" gate 470 of first logic means 46 and
directly to first solenoid 134 via line 62. In addition
to the aforementioned capability of "nor" gates, such
gates can receive more than a single signal. When "nor"
gates do receive plural signals and those ~ignals are
only 0 signals, the gate will produce a 1 siynal, and
when any signal received i~ a 1 signal a 0 signal will
be produced. Of course, any signal or the absence there-
of transmitted from skid control logic 54 directly to
line ~2 via line 54 is unaltered.
A "deadband" portion is included in first logic
means 46 and is graphically illustrated in FIG. 5. The
purpose of the deadband is to preclude simultaneous
-20 actuation of both solenoids 134, 136 within a predeter-
minded band width. Without such a deadband it would be
possible for both solenoids to be simultaneously actuated
in which case the air supply from reservoirs 18, 36 would
be rapidly depleted. Such simultaneous actuation of both
solenoids could conceivably occur when transducers
42, 50 sensed equivalent pressures and sent identical
signals to logic means 46. The deadband may be of
-- 19 --
~3 ~ L
a predetermined width such as or example 5 psi
representing a 5 mv signal (i~e. from minus 2.5 psi
to plus 2.5 psi) as shown in FIG. 5. Thus,. the
deadband precludes simultaneous actuation of b~th
solenoids not only where pressures sensed at both
transducers ar~ ~q~ivalent but when those prassures
are wi~hin a predetermined pressure differentia:L
band width of, as in this case, 5 psi.
In FIG. 4, it can be seen that the deadband
is provided in logic means 46 due to the inclusion
of a constant signal input of minus (-) .25 mv to
simulate a pressure o~ mlnus (-) 2.5 p9i at compara~or
454 and a sinlllar input signa:l at complr~tor 4~2, ~llC]
further due to the inclusion of "nor" gates L70 and 482.
The deadband can be widened or narrowed by appropriately
changlng the values of the constant input signals at
comparators 454, 442. Thus, the values of the constant
input signals determine the width of the band whereas the
inclusion of "nor" gate 470 between "and" gates 460, 474,
. 20 and the inclusion of "nor" gate 482 between "and" gates
448, 486 preclude simultaneously actuated signals from
reaching solenoids 136, 134, respectively,
The foregoing is illustrated in FIG. 5 where it
I is shown by the line designated B, the inverse of which
! 25 is shown by the line designated C :Eor descrLptive,purposes,
that where the pressure sensed at transducer 50 is..greater
than that sens~d at transducer 42~ as the pressure differ-
ential decreases, the possibility oE both solenoids 134,
136 simultaneously actuating ~ precluded within a prede-
termined deadband of 5 psi (i.e. minus 2.5 to plus 2.5).
,
~ - 20 -
1 C338Q~
Similarly, as is shown by the line designated A, that
where the pressure sensed at transducer 42 is greater
than that sensed at transducer 50, as the pressure .
differential decreases, thc possibility of both solenoids
134, 136 simultaneously actuating is precluded within
the predctermined deadhand.
Oper at ion:
During the application mode, that is, when the
vehicle operator applies foot pressure to pedal 64, fluid
pressure is released rom first reservoir 18 through
~_~ application valve 16 to the :Eront tractor brakes via
conduit 23, to th~ rear tractor bralces vitl conduit 30 and
to relay valva 40 vi.a conduit 22. Thus a :~irsl: :impul~e
o~ :Eluid pressure is produced at :eirst valve 16 and
15 . con~nunicated toward second valve 40 via conduit 22. The
f irst impulse may enter valve 40 at port 72 and pass
through a first passageway comprising passages 130, 126
into opening L23 and furt:her through passage 118 to upper
~, chamber 508 to co~nunicate with and cause a ~irst downward
force on upper surface 308 of piston 306. This downward
force is opposed by an oppositely acting upward force due
to spring 328 acting on lower surf ace 322 of piston 306 .
However, due to the remotenass of valve 40 r~lative to
valve 16, a substantial delay is experienced in co~nuni-
cating the first impulse to valve 40,
Under the above-describel conditions, t:ransducer
42 connected to conduit 22 adjacent valve 16, senses a
pressure that is relatively hi~her than the pressurc sensed
by transducer 50 connected ko conduit 48 acljacent valve
40. Thus transducers 42 and 50 produce signals proportional
- 21 -
to their respective ~ ~ ensed, The signal from
transducer 42 is communicated to logic means 46 via
electrical connection 44 while the signal from transducer
50 is communicated to logic means 46 via elect~ical
connèctor 52. The signal fro~l transducer 42 to logic
means 46 is transmitted much aster than the ~irst
impulse can be communicated to valve 40 via condult 22.
With the logic means 46 provided as hereinabove
set forth a 1 signal is sent from logic means 46 to
solenoid 136 of valve 40 and a 0 signal is sent to
solenoid 134. The signal sent to solenoid 136 actuates
this normally clos~d solenoid and op~ns a second plssag~-
way çornpr:Lsing passages 132, 128 into opanlng 125 ancl
further into passags 120to admit a second impulse o~ fluid
pressure ~rom second reservoir 36 to upper chamber por-
tion 508 to con~lunicate with and cause a second downward
force on upper surface 308 o~ piston 306. This second
downward force precedes the irst force resulting from
the first impulse to act on piston 306. Since the
tractor-trailer fluid pressura systems are interconnected
via conduit 38, the first and second impulses can equalize.
Fluid pressure from second reservoir 36 is in
constant communication with inlet port 216 of valve 40.
This fluid pressure is normally precluded from communica-
tion with the lower surface 322 of piston 306 i.n lower
chambcr 510 due to sealing member 262 and s~ating portion
222 being urged into sealing engagement by spring 268,
Th~ second downward Eorce is opposed by the ~orce exerted
by spring 328 and since lower chamber 5L0 ;s in open ~luid
communication with the atmosphere via exhaust port 219,
.
- 22 -
1 ~ 3 ~
piston 306 is forced downwardly so that annular seat 326 of
piston 306 engages sealing portion 262 of piston 250 to
interrupt fluid communication between lower chamber 510 and
exhaust port 219 and open fluid communication between lower
chamber 510 and second container 36 whereby a third iippulse
o~ 1uLd pressure at lnlet 21fi ;.s adrnitted into ;~wer cham-
ber 510. This third impulse can equalize with the first
and second impulses due to the interconnection of reser-
voirs 18 and 36, This immediately causes an upward force
applied to lower piston surface 322 sufficient to drive pis-
ton 306 upward in chamber 506 slnce.~luid pressures acting
~J on opposite sldes of piston 306 are substantial:ly aqual and
the ~luid force on lower surfclce 3~2 is a:lcled by the upward
force exerted by sprLng 328. When ~he ~hird impulse of
fluid pressure is admitted into lower chamber 510 this
causes the third impulse of fluid ~ressure to be almost
immediately communicated to the trailer brakes via recess
210, outlet 212 and fluid conduit 48. ~s a result a sudden
pressure rise is sensed in conduit 48 by transducer 50 which
0 transmits a proportional signal to logic means 46 via lina 52.
The holding mode of this system follows the initial
application mode whereby the vehicle operator can forsee-
ably hold downward pressure on pedal 64 of application
valve 16 and the third impulse of fluid pressure has been
communicated to the trailer brakes, The pr~ssure rise
sensed by transducer S0 can increase to a pressure sub-
stantially equaL to the pressure sensed by tr:ansducer 42.
At this point it can be appreciated that, in view of ~he
foregoing description o ~irst logic mealls 46, when
pressure sensed by transducer S0 is at least as high as
- 2.3 -
~3~30~3L
the pressure sensed by transducer 42, a 0 signal is
produced from the first logic means and sent to second
solenoid 136 along line 60 and a 0 signal is sent to first
solenoid 134 along line 62. A 0 signal to the~second
solenoid causes that solenoid to return to its normally
closed positlon'thus ln~errupt~ng communicati,on of the
second impulse from reservoir 36 to upper chamber 508.
However, upper chamber 508 remainsin fluid communication
with conduit 22 in which the first impulse was generated.
Thus, the first impulse provides substantially the same
pressure in upper chamber 508 as was,provided by the
second impulse. Fluld pressure chambers 508, 510 beLng
exposed to substalltially ~qual pre~sure, plstorl 306 i9
provided to posltion it9elf within chamber 506 so th~t
both seating areas 326, 222 aro in sealing engagement
with sealing portion 262 thus interrupting flui~ communi-
cation between lower chamber 510 and inlet 216 and between
chamber 510 and exhaust passage 219, Thus, the third
impulse of fluid pressure remains isolated between lower
chamber 510 and the rear trailer brake actuators. In
this manner, the pressures sensed at transducers 42, 50
remain substantially equalO
The release mode of this system generally follows
the holding mode wh~rcin, as hereinbefore discussed,
pressures sensed at transducers 42 and 50 are substantially
equal. The release mode is caused by removal of foot
pressure from pedal 64 by the vehicle operator. Such
removal o Eoot pressure at valve 16 cuts oEf or in~er-
rupts the irst impulse of fluid pressure bein~ supplied
from Eirst reservoir 18 to relay valve 40 via conduit 22.
- 2~ -
J~ 1
~ ~3 ~
Thus, transducer 42 immediately senses a pressure drop
and sends a proportional signal to ~irst logic means 46.
At this point therefore, kransducer 50 is sensing pressure
higher than the pressure sensed by transducer 42 and is
sending a signa~ proportional thereto to ~irst logic
means 4~ via li.ne 52. Therefore~ 1~ can be appreciat~d
that in view o~ the ~oregoing description of logic means
46, when pressure sensed by transducer 50 is higher than
pressure s~nsed by transducer 42, a 0 signal is produced
10 from the first logic maans and sent to second solenoid
136 along line 60 and ca 1 signal is sent to :E:irst
~J solcnoid 134 along lin~ 62. ~ 1 signal to ~irst solanoid
134 actu~tes thcat solenold rom :Lts norml~lly op~n pos:L-
tion pcrmitting flui.d commulll.c~tion bctw~en condult 22
and upper chambar 508 via the first passageway to a
closed position whereby sealing swr~ace 146b seats
against seating area 123a to interrupt fluid communication
in.the first passageway particularly between passage 126
and opening 123, As a result, fluid pressure in upper
e~2o chamber 508 is permitted to exhaust back through passage
118 into opening 123 and then through passage 164, exhaust
passage 158 and ultimately to atmosphere through unsealed
solenoid chamber 101. Any ~xcess pressure remaining in
passagas 126 and 130 is cxhausted back through port 72
and conduit 22. Further exhau~ting o~ ch~mbar 508 is
accomplish~d due to a pressurc drop i.n challlber 508 which
permits relatively higher pressurc in lower challlber 510
to ~orce piston 306 upwardly, Thus, se~ting area 326 -ls
ur~ad out o~ sealing engagement with sealing portion 262
which permits pressure in conduit 48 to exhaust through
- 25 -
~ O ~ 8 0 0 ~
outlet 212, rocess 210, chamber 510 and ultimataly to
atmosphere via exhaust port 219,
The foregoing generally describes operational
characteristics of similarly known fluid pressure relay
brake systems although the above-d~scribed system
includes a relay valve 40 and lo~ic means 46 having novel
provisions incorporated ~herein.
With the advsnt of skid control systems, the
known ~luid pressure relay brake systems were found to be
incompatible t~ rewithO The novel relay valve 40 of ~his
invention ~unctions with the Eluid rel.ay brake syst~ms to
~J .
give simllar results to those given in Icnown systems
dur-.Lng the normal application, holdLng and rel~asa modos,
but due to the novel provisions o~ the valve and ~irst
logic means 46, compatibility between the fluid relay
system and skid control systems is achieved,
Thus, during the application mode, as h~reinabove
set forth, pressure sensed at transducer 42 is greater
than pressure sensed at transducer 50 and proportional
-
~0 signals are sent by the transducers to first logic means
46~ With the logic means 46 provided as stated above, it
can be appreciated that "nor" gate 470 receives a 0 signal
from "and" gate 460 via lines 464, 468, That 0 signal is
converted to a 1 signal. Thus, a 1 signal is produced at
"and" gate 474 and solenoid 136 is actuat~d to ultimatcly
permit vlave 40 to communicate 1uid pressure ~rom reser-
voir 36 to the rear trailer brakes while a 0 signal is
pxoduced at "and" gate 486 so that normally open solenoicl
134 remains Op~rl to permit 1uid communication between
reservoir 18 and piston 3Q6 of va].ve 40. However, should
- 26 -
~ ~3 ~
an impending skid condition exist~ skid control logic
means 54 sends a 1 signal to "nor" gate 470 via line 56
and also a 1 signal is sent directly to first solenoid
134 via line 58 to line 62. ~s earlier described, "nor"
S gate 470 having received multiple signals any o~ which,
is a 1 signal, then a 0 signal is produced. rhus, the
~esult is that a O signal is produced at "and" gate 474
to deactuate the actuated solenoid 136 so as to omit
fluid pressure communication from reservoir 36 to the
.10 rear trailer brakes. Also, a 1 signal is sent directly
to normally open solenoid 134 via lines 58 and 62 so that
solenoi~ 13l~ is actuat~d to close thus om:Ltting ~lui.d
communication between reservoir 1~ and piston 306 o.~
valve 40. Thus, the novel provi~:ions oE the intercon-
nection of logic means 46 and 54 and the novel provisions
of relay valve 40 provide a simulated release mode in
the fluid pressure relay system even though ~oot pressure
is still being applied to pedal 64. If, however, no
impending skid conditions exist, it can be seen that
~20 interconnection of logic means 46 and 54, when logic
means 54 is producing 0 signal, has no effect on the ,
normal functioning of the relay system,
- During the holding mode, as hereinbeore set
Eorth, pressure sensed at transducers 42 and 50 are
substantially equal and proportional signals are sen~ by
the transducers to first logic means 46. With logic
means 46 provided as stated above, it can be appreciated.
that "nor" gate 470 receives,a 1 signal from "and" gata
460 via lines 464, 468. That 1 signal is converted into
a 0 signal, Thus, a 0 signal is produced at "and" gate
- 27 -
~ ~3 ~
474 and solenoid 136 is deactuated to ultimately limit
valve 40 to further communicate fluid pressure from
reservoir 36 to the rear trailer brakes while a O signal
is produce~ at "and" gate 486 so that normally~open
solenoid 134 remains open to permit fluid communicatio
between reservoir 18 and piston ~n6 ~E valve 40,
~owever, should an impending skid condition exist, skid
control logic means 54 sends a 1 signal to l'nor'l gate 470
via line 56 and also a 1 signal is sent directly to first
solenoid 134 via line 58 to lin~ 62. ~s earlier described,
"norl' gate 470 having received multiple signals any of
which is a 1 si.gnal, then a O signal is produced Thus,
the result i.s that a O slgnal i9 produced at "ancl" ga~e
474 as befor~ so as to have no e~ect on sol~mo:Lcl 136
and omi~ 1uid pressure col~munication from reservoir 36
to the rear ~railer brakes, Also, a 1 signal is sent
directly to normally open solenoid 134 via lines 58 and
62 so that solenoid 134 is actuated to close thus omitting
fluid communication between r~servoir 18 and piston 306
O of valve 40. Thus, the novel provisions of the inter-
connection of logic means 46 and 54 and the novel provi-
sions of relay valve 40 provide a simulated release mode
in the fluid pressure relay system even though foot
pressure is still being applied to pedal 64. If, however,
no impending skid conditions exist, it can be seen that
interconnection of logic means 46 and 54, when lo~ic
means 54 is producing O signal, has no effect on the
normal functioning o~ the relay system.
Obviously, during the release rnode, no impending
skid conditi.ons are sensed inasmuch as the release mode
- 28 ~
~38~
is the mode during which there is no braking action
occurring at application valve 16.
With logic means 46 provided as hereinabove
described the minus (-) .25 mv constant signal~input at
comparator 454 and a similar signal input at comparator
442 can alter the signal receive~ from adders 420, 408,
respectively, Also "nor" gat~s 470, 482 can alter
the signals they receive and send on to 'land" gates
474, 486, respectiv~ly. As a result, the potential
simultaneous actuation o both solenolds is precluded.
The foregoing has described a system and a
valve for use therein to make that system compatible
with skid control systems in tractor-tr~iler
combinations, It is anticipated that modificatlolls
and variations of the present invention are possible
in the light of the above teachings. It is, therefore,
to be understood th~ within the scope of the appended
claims the invention may be practiced other~ise than
as specifically described.
,
- 29 -
