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Патент USA US2132913

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Octf 11, 1932s.
B. s.> AIKMAN
2,132,913’
BRAKE CONTROL MEANS
Filed July 6, 1955
INVENTOR
EmRToN _5. AIKMAN
:.2:
A
ì
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M ß
ATTORN EY
Patented Oct. 11, 1938
2,132,913
?UMTED STA-TES » PATENT OFFICE i
BRAKE coN'rrRoL MEANS
Burton S. Aikman, Wilkinsbur'g, Pa., assignor to
The Westinghouse Air Brake Company, Wil
merding, Pa., a corporation of Pennsylvania
Application July 6, 1935, Serial No. 30,121
'
Q 2s claims.V
(o1. soséiy
My invention relates to brake control means .
for vehicles and more particularly to means for
controlling braking equipment to' prevent the
Wheels from sliding.
My invention has application to iiuid pressure
5
ates intermittently to progressively reduce brake
cylinder pressure during a brake application.
’It is a further object of my invention to pro
vide a brake force releasing device for inter
brake equipment employed on railway trains and’
traction vehicles and is effective to intermittently
mittent reduction'of brake cylinder pressure, the
counteract the eñect of high brake cylinder pres- '
10
sure during a brake application, at sufficiently
frequency of operation of which is such that a
high brake cylinder pressure will not be in force
frequent intervals, to prevent a highk braking
a suñicientvlength of time at any one time, as 10
force from being maintained for a length of time
at any one time that is suiiicient to cause actual
wheel sliding as the vehicle speed reduces, and
to simultaneously cause a gradual reduction in
high brake cylinder pressure to a predetermined
low value.
It is well known that for a given braking pres
sure, friction type brakes are less effective in re
tarding the motion of a vehicleiat'high speed
the vehicle speed decreases, to cause actual Wheel
sliding at the existing vehicle speed.
`
comprising a brake equipment arranged in ac
cordance with one preferred embodiment of the
invention,
tion between the rubbing Vparts is lowerV at high
20
Fig. 2 is a view in vertical section through the
speed than at low speed. When a full service
or emergency brake application is made at high
brake cylinder and the braking force releasing
mechanism, and
speed the brake cylinder pressure developed will
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Fig. 3 is a sectional view taken on line 3_3
- exceed the pressure required to slide the wheels
on the rails as the speed of the vehicle decreases.
of Fig. 2.
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Referring to the drawing, a ñuid pressure
In order to bring a vehicle to a stop quickly, it brake equipment is illustrated in Fig. 1 in which
has been the usual practice for an operator to`> a brake cylinder VI is provided and is supplied
apply the brakes with a high degree of braking with fluid under pressure from an auxiliary res
pressure at high speed, and, as the speed of the _ ervoir 2 through a brake cylinder pipe 4 in ac
vehicle decreases,fto so operate the brakes as to cordance with the operation of a triple valve
cause the braking pressure to decrease rin such device 3 as controlled by the pressure in a brake
manner that the vehicle is brought to alstop pipe 5 in the usual way. A brake cylinder piston
quickly and smoothly, without sliding of the rod or stem 6 is operated in accordance with the
supply of fluid under pressure to the brake cyl
When railway trains and traction vehicles are inder I and is connected to the lever system in
operated at very high speeds, a correspondingly cluding levers 1, 8 and 9, the lever ‘I being con
Wheels.
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Other advantages and objects of my invention
Will appear from the following description of a
specific embodiment thereof taken in connection 15
with the accompanying drawing, in which
Fig. l is a diagrammatic view of apparatus
. than at low speed because the coeñicient of fric
,
It is another object of my invention to pro
vide a braking force releasing device which oper
25
v
high braking force must be employed to Ybring
nected to operate the levers I0, II, I2 and I3,
which -are pivotally connected together for oper
length of time. When such braking force isk ating theA brake shoes I5 and I6 against the
applied the problem of properly reducing the YWheels I1 and I8, respectively, that roll along the
braking force by manual operation as the vehicle rail> I9. 'The upperend of the lever I3 being
the train or vehicle to a stop in KVa reasonableY
slows down becomes a difficult one and there is pivctally'connected to the car frame I4, the lever
considerable danger of the wheels sliding on the ' V9 of the brake equipment similarly controls the
L rails. It is therefore desirable to provide, as a , operation ofthe pivotallyfinterconnected levers
part of the brake equipment on high speedtrains
21,22, 23 and 24, for pressing the shoes 26 and
and vehicles, means for automatically'reducing
2'! against the wheels 28 and 29', respectively.
the braking force suiiiciently to permit the'wheels
to maintain rotation and prevent their sliding
The'upper end of the lever 24 is pivotally‘ con
nected by the pin 25 toa point on the Vcar frame.
As illustrated, the'upper end of the lever 1 is 50
5.0.
It is an object of >my invention tovprovide a connected to the crosshead end 3I of the piston
brake equipment having a braking force releas-vk , stem 6,- and the upper end of the lever 9 is con
Von
the
rails.
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ing characteristic to intermittently relieve 'the'> neoted to a bifurcated portion 32 of the pressure
eilîect of high brake cylinder pressurersuiiiciently head ’of the brake cylinder I, so that movement
"
to prevent wheel sliding.
' ~
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e
of the crosshead 3| away from the pressure head, 55
2
2,132,913
and of the interlinked lever system connected
thereto, causes an equalized application of brak
» ing forces to the wheels l1, I9, 28 and 29.
The operating mechanism for the braking
force release device 33 is connected to the pres
sure head of the brake cylinder l, as best shown
in Fig. 2, and operates from brake cylinder pres
sure to partially reduce the braking force below
a value corresponding to brake cylinder pressure
10 at intervals determined by the timingr of the
releasing
device.
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The brake cylinder l comprises a casing en
closing a piston chamber 34 containing a piston
35 that is connected tc the piston stem or rod 5
which lextendsr outwardly kthrough the non
pressure head 39 of the brakecylinder I, and
mally limited by the average adhesion of the
car wheels to the rails. If the brake shoe forces
exceed this permissive value the adhesion of the
car Wheels to ,therails is insufficient to prevent
the wheels from sliding. Tests show, however, CTI
that'a brief period of time exists between what
is known as incipiency of Wheel sliding .and actual
wheel sliding, that is, a brake shoe pressure suffi
cient to cause wheel sliding can be exerted for a
short time without actually causing such sliding
Y `due to the time element involved.
. As the brakes are applied and brake cylinder
pressure increases within the piston chamber 34
to a predetermined value, the spring-weighted
valve piston 39 will be forced from its seat 49
toward the right against the bias of the spring
which is surrounded by a release spring 31, one Y 4|, 'thus permitting fluid under pressure to ñow
end of which engages the piston 35 and the other from the piston chamber 34 at piston chamber
end of which engages the non-pressure head 3G pressure, through passage 43,. to the piston
20 to bias the piston 35 toward-the right to a brake chamber 44 to force Vthe piston 45 and piston rod 20
releasing position. The braking force release
mechanism 33 comprises ak casing enclosing a
valve chamber 38 containing a spring-Weighted
valve piston 39 that is urged toits seat by a
25 spring 4| to close communication from the pis
ton chamber 34 through' passages 42 and 43, to
a piston chamber 44 containing a piston 45 that
is provided with a stem or piston rod Gil.
The braking force releasing mechanism also
contains a piston chamber 46 containing a piston
41, illustrated as positioned against a stop 48, and
provided with a stem49 that extends centrally
through the spring 4I, the end acting as a stop
` for limiting the movement of thev valve piston
35A 39 away from its seat. A chamber 5l between the
valve piston 39 and the piston 41 is connected to
the atmosphere through an exhaust port 52 so
that the pressure Within the chamber 5l is con
tinuously at atmospheric pressure. A restricted
passage 53 through the piston 41 permits the
gradual escape of ñuid under pressure from the
piston chamber 46 to the atmosphere.
A valve chamber 54 is provided, containing a
spring-weighted valve piston 55 that is urged to
45 its seat 56 by a spring 51, the lower end of which
engages the valve 55 and the upper end of which
engages the wall or partition forming the under
side of the chamber 5I. The valve piston 55 con
trols communication between the passage 43 and
the piston chamber 44 through passage 58 to the
piston chamber 46.
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The piston 45 is attached by a pin 59 to a piston
rod 6l that is pivoted by the pin 62 to a lever 63,
the Vupper'portio-n of which is provided with jaws
94 and 55 for gripping the piston rod 6 and
moving it slightly to the right, against the pres
sure in the piston chamber 34, upon the move
ment of the piston 45 and the piston rod 5| to
ward the left, The lever 93 is pivotallyy sup
60 ported upon .a pin 66 carried -by a link 61, the
, other end of which is pivotally supported by a`
6Iy toward the left, and to rock the lever 63 in
a clockwise direction to cause the jaws 54 and 65Y
at the upper end thereof to grip the piston rod 5,
through which the brakes are applied, and exert
force thereon opposing the force exerted by the 25
pressure within the piston chamber 34, thus
slightly decreasing the degree of application of
the brakes below that corresponding to brake
cylinder pressure. The degree of application of
the brakes will be reduced both by reason of the 30
force exerted through the lever 63, and because
of the reduction in the pressure of the fluid in
the brake cylinder chamber 34 as. the result of
the supply of fluid under pressure therefrom to
the release mechanism 33. As the pressure builds 35
up in the piston chamber 44 and in the passage
43 to brake cylinder pressure, the weighted valve
piston 55 is, at a predetermined pressure, also
forced upwardly from its seat 55 against the bias
of the spring 51, thus permitting the flow of ñuid 40
under pressure at brake cylinder pressure from
the passage 43 through passage 58 to the piston
chamber 46 to move the piston 41 against the
bias of the spring 4I until the piston stem 49
engages the valve piston 39 and forces it to its
seat 40.
It will be noted that the area of the valve
chamber 38, subject to piston chamber pressure
after the valve piston 39 has been moved from
its seat, is of considerably greater area than the
central portion of the valve >piston 39 that is
subject to brake cylinder pressure when the valve
piston 39 is seated.
As the result ofthe differ- Y
ential force on the'valve piston 39 tending to
urge it against the bias of the spring 4i when the 4
valve piston is seated and when it is unseated, a
considerable drop in brake> cylinder pressure be
low the valve necessary to unseat the valve piston
39 is required before the valve piston will again
seat, due to the pressure ofthe spring 4I there 60
on.
It will also be noted that Ythe area of the
pin 98 on thenon-pressure head 33 of the brake piston 41, that is subject to'brake cylinder pres
cylinder'. A 'spring 69 is provided, one end of sure after the valve piston 55 has become un
which is connected to the lower end of the lever seated, is greater than the area of the valve
53 and the other rend of which is connected to the piston 39 that is subject to brake cylinder pres 65
non-pressure head 36 for urging the lever 53 in a ' sure in the valve chamber 38, so that, as soon as
counterclockwise direction and forcing the piston pressure-builds up to a predetermined value in
the piston chamber 45, the piston 41 acting
"rod 9 Iv and the piston 45 toward the rightto per
through the stem 49 will force the valve piston
mitV free movement of the piston rod 6 in ac
V cordance with changes in pressure in the piston 39 to its seat 49, and thereby cut off the supply
Yof fluid under pressure from the brake cylinder 70
chamber 34.
l '
.,
VIn order to understand the operation of ap
plicant’s invention, it should be borne in'mind
that the permissible braking forces exerted by
75 the brake shoes uponthe car wheels are nor
chamber 34 to the chamber 38 of the release
mechanism 33, and prevent a further reduction
in the pressure of the fluid in the brake cylinder
chamber 34.l Fluid under pressure is released 75
3
gradually from the piston'cnamßer 46,`Ã> and from prede't'ermi'ned> vdegree »to Veiïect a corresponding
the piston chamber 4'4ran`d the valve-‘chamber 38; application» ofthe brakes, the lever 63 -acting
'through the restricted passage 53"and¿port.52 through‘the jaws-64 and 65 exeïrts force on the
to the
atmosphere..
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It wur be noted that `when >the valve spis'toi‘r` 55
is unseated, permitting` fluid Vatm-brake ‘cylinder
pressure to flow tothe piston ‘chamber '46, the
full area of the valve piston is‘expos'ed to brake
piston rod in 'a' brake releasing direction to re
duce the degree of application of the brakes an C11
amount suilicient to prevent the wheels from
sliding on the rails».w At the same time the pres
sure ’of the fluid
the brake Vcylinder is reduced
cylinder pressure, so that, after the valve piston y by the supply of fluid under pressure from the
is opened, the valve piston will b'e held open un#> brake cylinder to the release «mechanism 33, with 10
til fluid pressure acting on the f'valve piston has . the result that the ydegreeof brake application
been» reduced to 'a vconsiderable degree 2less .than ' which 'the ¿brake cylinder can effect is correspond
the degree of ñuid Íp‘ressure required to open the _ingly reduced.1 At a short time interval there
valve. V-The effect of the differential-:areas be- ` after the lever ‘63 is` permitted to move in 4a
tweenV the central porti‘onffof the valve piston 55,y
that is subject to the pressure withinrthe pas’
sage 43, and the larger area o-Íf -th'e valvepiston,
that is subject to- the pressure :within the valve
chamber 54, is to require a ‘considerable vdecrease
in pressure within the passage :43 and fv'alve ch‘am
berV 54, after the valve piston has been unseated,
below the value necessary to unseat it, 4before :the
valve piston will again seat. _SW-hen, as `a result
of the release of fluid under pressure tothe'at
co'unterclockwise direction ïto release its grip upon 15
Ythe piston rod 6 and permit the >reapplimation »of
mosphere through the restricted .passagei53 `in
ïmeans of relieving the brake shoe -pressure
will reduce in small increments the brakecylinder
pressure and the 4brake shoe 'pressure resulting
therefrom, so that, -as the speed of the train is
reduced, 'and the coeflicient lof friction between
the brake shoes "and 'the ‘car 'wheels is increased, 30
the brake cylinder pressure >will be ’reduced ‘at
the Ípiston 4l, the pressure -in the valvechamber
54 has been reduced vsufñeient'ly’to permit the
valve piston 55 to seat, the pressure in the piston
chamber 44 will have permitted the piston '45
30 to be moved to its illustra-ted position by the
spring _ 69, thus disengaging lthe jaws; 64 and
65 from the »piston rodY v6 and permitting. the
brakes to be. applied to a value corresponding to
the pressure Within the piston. chamber '34 fof
the
' Asbrake
the pressure
cylinder within
AI.
the piston-chamber`
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'Y 46
the brakes tothe full value of brake cylinder pres
sure„,which~-, aspointed out above, has been vre
duced somewhat bythe release of vfluid therefrom.
The frequency 'of operation oï the partial release 20
of¿ thebrakes is' such that high brake lcylinder
pressure willnot continue -`for a sufficient length
ofjti‘meftofeffect actual Wheel sliding 4but will beV
reduced at 'the incipient stage of ’wheel sliding. ~ '
a rate to provide 'the 1maximum rate of decelera
tion of the vehicle until a Alow vehicle speed is
reached, when the brake cylinder pressure will
have been reduced to such value that «the braking 35
Vforces will produce a smoothl stop.
While one preferred embodiment of-my-inven
decreases due to» the release ‘of fluid underpres
sure through the restricted passage 53, theiorce tion has been illustrated land described, it will >be
of the piston stem 49 against 'the valve :piston 39 Vapparent to those skilled in the lart ¿that many
40 is reduced, and the piston 41 and.stem«-r49 :are modifications `in the ïapparatus illustrated may
moved by the force of ‘the spring 4l ‘against v,the ~ be made within 'the spirit of my ’invention >and
l stop 48, as illustrated, thusjpermitting'the valve Iïdo not wish to‘be limited ’otherwise't'haniby'the
piston 39 to again be unseated due to themes'.-v »scope of the'appended claims.
sure withinïthe «piston chamber v34 ¿as >applied. to
Having 'now described my -invention, ‘what nI
the central smaller area Aof the valve piston 39> I claim'as new and desire to secure by-Letters Pat
through passage 42, thus repeating the-cycle ofV ent, is:
operation just above described, causing the ¿piston
1. Ina brake equipment for vehicles, 'a vbrake
45 -to be forced to the vleft to again/exert ~force` cylinder, means for supplying ‘fluid under :pres
on the piston rod l6 `tending A»to ~move Yit 4'toward
the right to decrease t-he brake shoe `pressure
somewhat below that corresponding to brake’cyl-A
inder pressure within Athe >piston Ichamber 34,
45
sure to said 'brake cylinder to apply the brakes,
and means subjectlto brake cylinder pressure and
operative upon a predetermined brake `cylinder
pressure for effecting va partial -release :df `the
while'the pressure ofthe -iluid in the ‘brake cyliri--` Vbraking force 'occasioned Vby the-brake >cylinder
der chamber 34 is further reduced -by'the supply pressure for a short interval vof time, and for
of fluid therefrom to the releasing mechanism33. thereafter interrupting said brake releasing force
-Likewise, as the pressure withinr'the piston cham: ' toipermitfreapplication'of ‘the brakes'to a value
.
ber 44 builds iup ‘to a »value‘suñicienttoexertf corresponding -to brake'cylinderl‘pressure.
‘2.’ Ina brakelequipment for vehicles, a‘brake
Vsubstantial force on the piston: 45, -the ¿pressure
of fluid supplied from the‘brake‘cylinderthrough cylinden‘meansl for supplying iiuid under pres
-
the passage 43 will build up to a `value sufiicient ’ sure to saidgbrake cylinder to'apply=the brakes, 60
to force the valve piston >55 upwardly' from its l ` and means subject -to brake cylinder pressure and
seat against the bias of the spring5'l -andreiïect operative upon a predetermined ‘brake -cylinder
the supply of `fluid under pressure `»to thepiston pressure for effecting a partial 'release of 'the
chamber 46 to again 'cause the seating-»of `the >braking force occasioned by .thebrake vcylinder
pressure, and means for Vintermittentlyreducing
valve pistonr 39.1
l,
These cycles ~of operation are repeated until
thepressurein the piston chamber 34 of the brake
cylinder I has Vdecreased to yavalue depending
upon the setting of the'spring 4l below‘which
the fluid vat brake cylinder lpressure, vsupplied
saidbrake cylinder pressure `in a step by step
manner toiprevent the wheelsffrom sliding on the
rails.
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` 3. >In -a brake Aequipmentfor vehicles, 'a'brake
cylinder, means -forl supplying -ñuid under -pres
through the passage'42 to the Vseated area;of Y sureto said brake cylinder to apply-the brakes,
valvepiston A3ilyis‘insuilicient to force the valve
means subjectV to brake :cylinder pressure .and
piston 39 from its seat 40.
operative Aupon ¿a predetermined brake cylinder
Y
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Y
-It will be noted 'that immediately after’the 3 pressure -for >effecting >a -reductionßin‘thelbraking
brake cylinder‘pressure has ‘been `increased tofa force below that correspondingzto‘lbrake cylinder
4
pressure, meansfsubject to the operation of said
last mentioned «means for aeffecting a predeter-A
pressure to said pressure operated means, and
means subject to the pressure inY said pressure
mined reduction in brake cylinder> pressure and
for effecting a reapplicationjof the brakes in ac
of said braking force reducing means.
« cordance with brake cylinder pressure.
4. In
operated means for interrupting> the operation
10. In abrake equipment for vehicles, a brake '
brake equipment for vehicles, .a brake
`cylinder, meansfor supplying fluidr under pres
sure to said .brake cylinder to apply the brakes,
means for preventing the sliding of the Wheels
comprising means responsive to a predetermined
brake cylinder pressure for effecting a reduction
in the braking force below the value correspond
ing to brake cylinder pressure, a reduction in
lbrake cylinder pressure, and a full application of
” the brakes in accordance with the reduced brake
cylinder, means for supplying fluid under pres
sure to said brake cylinder,V to apply the brakes,
means for reducing the sliding of the Wheelson
the railsV comprising a pressure operated’brak
_ing force reducingmeans for reducing >the degree
l0
of application of the brakes below a value cor
responding to the pressure on the brake cylinder
pistoma weightedÍvalve` subject to .brake cylin
ïder pressure foreifecting the supply of fluid un
der pressure from said brake (cylinder to said 15
cylinder pressure.v
pressure operated means, and means subject to
. 5. In abrake equipment .for vehicles', a brakel the pressure irl-said pressure operated means fory
cylinder, meansgfor supplying iiuid under pres
surewto said brake cylinder to apply the brakes,
from said brake cylinder and for gradually re
leasing fluidrunder pressure from said pressurel
means subject to Vbrake, _cylinder pressure andV
operative upon a predetermined brake cylinder
operated braking forcereducing means to effect
pressure for effecting a recurring decrease in
a reapplication >of the brakes in accordance with
braking force belowthat corresponding to brake
brake cylinder.- pressure.
« cylinder Vpressure-¿ai reduction in brake cylinder
pressure, and a reapplication of the brakes in ac-Y
` cordance with brake. cylinder pressure.
6. In a brake equipment for vehicles, a brake
cylinder, means'for supplying fluid under pres
sure to said brake cylinder tofapply the brakes,
means for preventing wheel slipping comprising
means for intermittently effecting a reduction in
brake cylinderv pressure and for effecting an al
ternate reduction in the braking force below
brake cylinder pressure and a reapplication of
the’brakes in accordance with the reduced brake Y
cylinder pressure.
49
interrupting the 'flowA of fluid runder pressure
v
'7. In a brake equipment for vehicles, a brake
cylinder, means for supplying fluid under pres
sure to said brake cylinder to apply the brakes,
a braking force reducing means subject to brake
cylinder pressure and operative upon a brake
cylinder vpressure above a predetermined value
for effecting a 4reduction in braking force below
that corresponding to brake cylinder'pressure,
4.5 means responsive >to the operation of said last
Y.
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V11. In a brake equipment-for vehicles, a brake
cylinder, means for supplying fluid under pres 25
sure to said brake cylinder to apply the brakes,
means forreducing the sliding of the wheels on
the rails comprising a pressureoperated brak
ing force reducing means for reducing the de
grec of application of the brakes'below a valve 30
corresponding to the pressure on the brake cyl
inder piston, a weighted valve'subject to brake
cylinder pressure for effecting the supply of fluid'
under pressure from said brake cylinder to said
pressure operated means upon anincrease in
brake cylinder pressure above a predetermined
value, and means subject tothe pressure in said
pressure operated means .for interrupting the
operation of said braking force reducingV means
and for effecting a reduction in brake cylinder
pressure upon the increase in pressure in said
pressure operated means above a predetermined
value.V
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12. Ina brake equipment for vehicles, a brake
cylinder, means for supplying fluid under pres- ,
named means for effecting a reduction in brake v sure to said brake cylinder to apply the brakes,
cylinder pressure and for` interrupting the op
50
eration of said braking force reducing means to
permit a reapplication of the braking force to a
valve corresponding to the reduced brake cyl
inder pressure.
.
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8. In a brake equipment for vehicles, a brake
cylinder, means for supplying fluid under pressure
means for reducing the sliding of the wheels on
the rails comprising a pressure operated braking
force reducing'means forY reducing the degree of
application of the brakes below a value corre
sponding to the pressure on the brake cyiinder .
piston, a Weighted valvey subject to brake cylinder
pressure for effecting the supply of fluid under
to said brake cylinder to apply the' brakes, a brak
ing force reducing means subject to brake cyl
pressure from said ubrake cylinder to said pres
sure operated means, a weighted valve subject
inder pressure and operative upon a Ybrake cyl-V to the pressure in said pressure operated means
inder pressure above a predetermined value for >forv effecting the _movement of said ñrst named
effecting a recurring cycle of operation to effect weighted valve to close communication to said
a reduction in braking force below that corre
pressure operated means, and means for reduc
sponding to brake cylinder pressure, a reduction ing the pressure in said pressure operated means 60
in brake Cylinder pressure, and the'interruption to permit a reapplication of the -brakes
cor
of the operation of said braking force reducing
respondence with brake cylinder pressure.
'
means Vto permit a reapplication of the braking
13.» lnV abrake equipment for vehicles, a brake
fore-e to a value corresponding to the reduced A cylinder, means for supplying ñuid under pres
Y
65 brake cylinder pressure.
sure to said brake cylinder to applythe brakes,
9= In a’brake equipment for vehicles, a brake a braking force reducing meanssubject to brake
cylinder, means for-‘supplying fluid underY pres
cylinder pressure and operative upon a brake
sure to said'brake cylinder to apply the brakes,` cylinder pressure abovera predetermined value
means for reducing the sliding of the Wheels on for effecting a reduction in braking force below
the‘rails comprising a pressure operated braking
force reducing means for reducing the degree 'of'
V,application of the brakesbelow a value corre
spending to thepressure on the brake cylinder
piston, a weighted valve subject to lic-rake cylinder
7.5 pressure»foreiîectingthe supply of ñuid under
that correspondingr to brake „cylinder pressure -
comprising a pressure operated means for op
posing tl’ie effect of saidV brake cylinder pressure,
valve means for effecting the’ supply Vof fluid
under pressure thereto in 4accordance with brake
cylinder pressure, and> means for, Veffecting a 75
5
2,132,913
partial, release of fluid under pressure therefrom"
Y to Vinterrupt the operation of said braking _force
reducing means.
Y
14. In a brake equipment for vehicles, a brake
cylinder, means for supplying fluid under pres
sure to said brake cylinder to apply the brakes,
a braking force reducing means subject to brake
cylinder pressure and Aoperative upon‘ a Vbrake
¿17, In‘ a brake „equipment for vehicles, a 'brake
cylinder, means for supplying fluid under pres
sure toY said brake cylinder to‘apply the brakes,
a braking force reducing >means forv reducing
.the braking force below the value correspond
ing> to brake vcylinder pressure, having a brake
rreducing pressure chamber and a weighted valve
Vresponsive to brake cylindery pressure above a
predetermined _value for effecting the supply of
cylinder pressure above a predetermined-value
for effecting a reduction in braking force below l fluid under, pressurefrom said brake cylinder to
that corresponding to brake cylinder pressure ' said chamber, apressure operated means having
andl comprising pressure operated` means for
opposing the effect of 'said brake cylinder
pressure,1valve means for effecting the ‘supply
Yof fluid under'pressure thereto in accordance
a stem for urging said weighted valve to its seat,
and means responsive to the pressure in said
pressure chamber> above a predetermined value
for Vsupplying :fluid under pressure from said
withV the brake cylinder pressure, and means for pressurefvchamber to said pressure operated .
'effecting a partial release of ñuidunder pressure ~ means 4toeffecua’release of said braking force
from said brake cylinder and from said pressure
operated means toA eñect a reapplication of the
18.,In a fluid pressure brake, in combination,
20 brakes in Yaccordance lwith "the reduced. brake
cylinder pressure.
,
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15. In a brake equipment for vehicles, a, brake
a brake cylinder,- a,brake_ cylinder piston there
20
in, means for supplying fluid under pressure to
said brake cylinder, av piston, means for opera
tively connecting said piston to the brake cyl
sure to said brake cylinder to apply theibrakes, inder piston to oppose> the pressure on the rbrake
a braking force reducing means for reducing ¿the , cylinder pistonby the fluid pressure acting on> 25
braking force below the value corresponding to saidopposing piston,'and means operated upon
brake cylinder pressure and havingxa braking Va predetermined increase -in brake cylinder pres
forcereducingpressure chamber, means respon-'î sure for >supplying fluid under pressure toßsaid'
cylinder, means for supplying'fluid under pres- ,
30
sive to brake cylinder pressure abovea predeter
mined value for effecting the supply of'fluid
opposing
piston.
'
'
.
'
‘
under pressure to said chamber at brake cylinder
pressure,.pressure operated means for interrupt
ing the supply of fluid under pressure to said
19. Inv a fluid pressure brake„in combination,
a brake cylinderya brake cylinder piston there
in, means-for supplying fluid under pressure to
said brake cylinder, a piston, means for opera
braking force reducing pressure chamber, means
tivelyconnectlng said piston to the brake cylin
35 responsive to the pressure in said pressure cham- Y
der piston <to oppose the pressure on the brake 35
ber‘above a predetermined Value for supplyingA >
cylinder piston;A by the fluid pressure acting on
fluid under pressure to‘VV said pressureoperated
means, and means forV releasing fluid under pres-
said opposing piston,»va1ve` meansy operated upon
sure from said braking force reducing pressure
40 chamber and from said pressure operated means
sure for'y supplying fluid under kpressure to said'
to effect the release of said braking force reduc- '
av predetermined increase in brake cylinder pres
opposingV piston, and means operated upon a pre 40
determinedzin‘crease vin `the pressure of fluid
supplied> to‘said .opposing piston for operating
ing means to» permit the reapplicationj of a brak
ing force Vin accordance Withbrake’cylinder pres
said pvalve meansto cut off the supply of fluid
sure, and the‘release of said'pressure operated'> to 'said opposing piston.
means to permitfurtheroperation of the means ,
responsive to brake cylinder vpressure for‘effect
ing a subsequent operation of saidbraking force
20. InA añuid pressure brake, inr combination,
a brake cylinder, means for supplying fluid un
der.. pressure toe the brake cylinder, Y.mechanism
operated upon a predetermined increase in brake
16. In` a brake equipment for`vehicles, a‘brake > cylinder pressure for reducing'the braking force
cylinder, means for supplying 'fluid under pres
eil‘ected by .the'increase'in brake cylinder pres
sure to said brake cylinder to apply the brakes,` sure,r and means operative after a predetermined
a braking force reducing means for.V reducing time intervalV for cutting said mechanism out of
the braking force below the value corresponding action. >.
'
reducing
means.
i
'
’
'
~
‘
to brake cylinderipressure having a brake re
' 21. Ina fluid pressure brake, in combination, a
ducing> pressure and chamber, means responsive
tobrake cylinder pressure above apredeterrnined
value for effecting the supply of fluid'under
brake cylinder, means for supplying fluid under
pressure to the Vbrake cylinder, mechanism oper
ated upon' a predetermined increase in brake cyl
pressure from said brake cylinder‘t'o said >cham-> , inder pressure for interposing a force to oppose
ber, pressure operated means Vfor’ interrupting the.` braking force set up by the increase in brakeV
the supply or" fluid under’pressure to saidbrake cylinderY pressure, Hand means operated after a (30
predetermined timelinterval‘for relieving said
reducing chamber, means responsive to the pres
sure in said pressure chamber above a 'predeter-Ä
mined value for supplying fluid under pressureV
from said pressure chamber to said pressure op
erated means, and means for. releasinggfluid
under pressure from saidbrake reducing pres
sureY chamber and from said pressure operated
means to effect a release of said` braking force
reducing means to permit a reapplication vof
the braking force in correspondence with brake
cylinder pressure, and a release of said pressure i
opposing
force.
.
`
.
Í
`
:ï
22. In aiñuid pressurebrake, in combination,
va.'«lîirake cylindena piston in said'brake cylinder
and operable on an increase in the'pressure of the
fluid therein to exertiforc'e to effect an application
of the brakes,>an ropposing piston `operative on
an increase in the pressure of the fluid supplied
thereto to exert force opposing the force exerted
by saidbrake‘cylinder piston,`and'means subject
to and operated on a. predetermined increase in
operated means to permit further operation of' ’
the pressureof the fluid supplied to the'brake
said means responsive to brake cylinder pressure
for effecting a subsequent operation of said brak
cylinder- to`supp1y fluid from the brake cylinder
to said opposing piston to'l reduce the -braking
ing force reducing means.
force below the value corresponding to the brake
'
'
6
areas 13
cylinder pressure >and to also reduce vbrake cylin for thereafter releasing fluid under pressure from
said pressure chamber to permit a reapplication
23. In a fluid pressure brake, in combination, a Y of the brakes in accordance with the reduced ap
brake cylinder, a piston in said brake cylinder plication chamber pressure.
'
der
pressure.
'
«
’
'
and operable on an increase in the pressure 0f
-the fluid therein to exert force to effect an appli
- 26. In a fluid pressure brake equipment for a
l)
vehicle having ra Wheel, in combination', a brake
cation of the brakes, `an opposing piston operative y cylinder, a piston mounted in said brake Ycylin
on'an lincrease in the pressure of the fluid sup
der and'having an application chamber vat the
plied’thereto to exert force opposingthe` force
lO Aexerted by said brake cylinder piston, means sub
ject to and operated on a predetermined increase
` in the pressure of the fluid supplied to the brake
cylinder to supply ñuid from »the brake cylinder
, to said opposing pistonv to reduce the braking
force below the value corresponding'to the brake
, cylinder pressure and to also reduce brake cyl
inder pressure, and means subject to and ’operat
~ ed on a predetermined increase in the pressure
of the fluid supplied to the opposing piston for
cutting off the supply of fluid to said piston and
for releasing fluid therefrom.
24. Ina vehicle fluid pressure brake equip
face thereof, said piston beingoperable on an in
crease in the pressure of the ñuid in said appli
cation chamber to exert braking force von said
Wheel to resistrotation thereof, the degree of
braking force varying in accordance with the in
crease in the‘pressure ofthe fluid’in said-appli
cation chamber, means for supplying fluidA under
pressure to said application chamber to increase
the pressure therein Vto a valuevwhich Vmay be
sufficient to produce braking force onV said Wheel
to a degree to prevent rotation thereof and to
thereafter cut off the supply of fluid under pres 20
sure to said application chamber', releasing means
operative on an increase in the pressure of the
ment,v in combination, brakingimeans, applica
ñuid in'a pressure chamber t0 exert force 0p
_tion means operative on an increase in the pres
posing that of the brake cylinder piston, means
sure of the-fluid in a pressure chamber to exert , for supplying ñuid under pressurefrom said ap 25
force to effectV an application'of saidY braking plication chamber to said _pressure chamber to
means, means for supplying'fluid under pressure thereby reduce the pressure of the ñuid in Vthe
to/said pressurechamber and to thereafter cut application chamber and reduce theV braking force
created by said brake cylinder piston and toalso
olf the supply of fluid under pressure thereto, re
30 leasing means 'op’erative’ on an increase in the
cause the releasing means to create aforce op
pressure ofthe fluid in a control chamber to ex
posing thatof the brake cylinder piston and
ert force-opposing said application means, and
thereby cause vthe effective braking force pro
duced by said brake cylinder piston to be re
duced below the- value corresponding lto appli
Y valve means for supplying fluid under pressure
from said pressure chamber to saidcontrol cham
ber, whereby the degree of application of said
f braking' means is reduced by the reduction in the
pressure `of the fluid in saidY pressure chamber
Y and by operation of'said releasing means, said
valve means-being thereafter operative to cut off
the supply of fluid under pressure from said pres
sure chamber to said control chamber and to re
. lease lluid from said control chamber to elîect
arreapplication of the braking means by said ap
plication means to a degree Vdetermined by the
cation chamber pressure, and ymeans for there
after releasing fluid‘under pressure from said
pressure chamber to permit a reapplication of
the brakes in accordance with the reduced ap
plication chamber pressure.
f
`
'
.
27. Vehicle brake apparatus comprising a brake a
cylinder, brake control means operative to con
trol kthe supply‘of fluid under pressure to and
the release of fluid under pressure from the
brake cylinder to effect Vapplication and release
pressure of the fluid remaining in the pressure
respectively of the brakes, means' providing a .
chamber(
chamber, means effective while said brake con
.~
‘
25. In a fluid pressure brakeequipment for a
vehicle having a Wheel, in combination, a brake
30
trol means'is conditionedto cause application ofVV
the brakes forA causing fluid under pressure to
cylinder, a’piston mounted in’said ‘brake cylin- . be supplied'from the brake cylinder to said cham
der and having an applicationv chamber Hfat the Y ber to reduce brake cylinder pressurefand con- ,
face thereof,said piston being operable on an in
sequéntly the degree of application of the brakes,
crease in the pressure of the fluid 5in said appli-V Vand means responsive to the pressure yin said
cation chamber to’exert braking. force varying chamber for exerting a force Yin opposition to
in accordance with the increase inthe pressure brake cylinder pressure to further reduce the
of the fluid in said application chamber, meansA
for supplying fluid under pressure to saidv appli-cation chamber and to thereafter Vcut off ‘the sup#
ply of' fluidunder pressure to said application
chamber, releasing means operative on' an 'in
effective degree of application of the brakes.
28. Vehicle brake apparatus comprising a brake
l cylinder, brakeV control means operative to con
trol the supply of‘iluid underY pressure to and
the release of fluid under pressure from the brake
crease‘in lthe pressure/of the fluid in a pressure ’ cylinder to effect application andVV release respec
60
chamber to exertforce opposing that of the brake tively of the -brakes, means providing a chamber,
' cylinder piston, means for releasing fluid ’under means automaticallyA effective while the brake
pressureV from said application ïchamber and to controlmeans .is conditioned‘tov cause applica
thereafter cut o'ffitherelease of fluid from said tion of the brakes for causing fluid under pres
- chamber to` maintainY the pressure Vtherein at a
lower value than that initially present therein
to therebyreduce the braking force created by
said brake 'cylinder piston, means for supplying
fluid under pressure to ’said pressure chamber
. concurrently with the release of ñuid from said
' application chamber to thereby cause'the effec
tive braking force created by said‘brake cylinder
piston to be reduced below‘the value correspond
ing to application chamber pressure, and means
sure to.V be supplied from vthe brake cylinder to
said chamber to reduce the brake cylinder pres
sure and consequently the ’degree of application
of the brakes, and means responsive to the pres
sure in? said chamber for exerting Va force in op
position to brakekcylinder pressure to further re 70
duce the effective degree of application of the
brakes.’ '
,
BURTON s. AIKMAN.'
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