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Jan. l0, 1950
H.
TREVASKlS
FLUID OPERATED BRAKE SYSTEM
Filed May 2. 1947
2,494,461
Patented Jan. 10, 1950
UNITEDi STATES PATE-NT OFI-‘lcs
FLUID OPERATED BRAKE SYSTEM
nem wuunm 'r1-mms. sounuu, Birmingham,
England, assignor to Dunlop Rubber Company
Limited, London County, England, a British
corporation
Application May 2, 1947, Serial No. 745,479
In Great Britain May 20, 1946
4Claims. (CL 18S-152)
2
l
My invention relates to fluid operated brake
systems for aircraft provided with duplicate sets
of‘controls for the iiuid transmission lines, one
pair of duplicate controls operating the brakes on
-one side of the aircraft'and the other pair of
_duplicate controls operating the brakes on the
other side oi' the aircraft.
In such brake systems it is known to provide,
in the iluid transmission lines from each pair of
duplicate controls to the corresponding brake 10
applying means, a valve unit which on the release
of iluid pressure by one control of the pair to
operate the brakes seals oil the nuid transmission
line connected to the other control. With brake '
systems of this type, however, it is possible for
one pilot to release the brakes inadvertently after
they have been applied by the other pilot for
parking purposes.
The present invention providesl means which
renders the pairs of duplicate controls inopera
tive when the brakes are in a parking condition.
According to the invention duid-operated
brake systems of the above type are provided
with a master control device adapted to place
through a line I1 and branches I l to the control
umts III and II, and similarly through a line I9
and branches 20 to the control umts Il and Il.
The pressure fluid supplied from the main i6
to the control units I0 andl I4 may be admitted
or released through supply pipes 2i and 22 to
one unit 23 oi a master control unit and thence
through a connecting line or delivery pipe 24 to
or from the brake I2 or to a suitable mechanism
to control the admission of iluid to the brakes.
Similarly fluid supplied from the main I6 may
be admitted or released through the supply pipes
' 25 and 26 to a second unit 21 of the master
control and thence through a supply pipe 28 to_
or from the brake apparatus I3. Each oi' the
brake apparatus I2 and I3 is, therefore, under
the independently acting controls III and II and
I4 and I5 respectivelythrough the master control
units 23 and 21.` These units may, however, be
set in “parking' position in which brake iluid
cannot be released from the brakes.
'I'he construction and operation of the master
control- unit 23 is shown in Figs. 2 and 3, it being
understood that control unit 21 is the same in
both the valve units simultaneously either in an 25 all respects. This unit comprises a box or cham
ber having a pair of spaced cylindrical bores 2l
operative position in which either pilot can re
and 30, the upper ends of which are closed re
lease iluid pressure through the valve units for
spectively by screw plug connectors 3l and 32
application of the brakes or in an inoperative
having passages for connection tothe supply
position in which the iiuid transmission lines
pipes 2|, 22, respectively.
for both pairs of controls to the valve units are
In the cylindrical bores 29 and 20 are valve
sealed oir. „
pistons 33 and 34 which `may move upwardly to
'I‘he various features of my invention are illus
close against valveseats formed on the bottoms
trated by way of example in the accompanying
of the connecting plugs BI and 32 respectively, or
'
'
Fig. 1 is a' diagrammatic representation of a 85 downwardly toward open position.
The chamber or box 23 is also provided with an
i'iuid operated aircraft braking system embody
outlet connector plug 35 which connects to the
lng my invention;
_
delivery pipe 2l.
Y
Fig. 2 is a sectional view on a larger scale of
The valve pistons 33 and 2| are pivotally con
a master control device to place the braking units
nected to the ends of a iloating lever 38 which is
simultaneously in operative or in inoperative po
secured at a point mid way of the valve pistons
sition and showing the parts in position to permit
23 and 34 to a bracket 31 movable vertically by
operation of the brakes;
means of a link 3B. This link passes through a
Fig. 3 is a view similar to that of Fig. 2 but
showing the parts'in “parking” or inoperative 45 fluid-tight packing gland 39 in the cover of the
chamber and is connected at its upper end in an
position.
`
articulated
connection to a cross-rod 40 4which
In the embodiment' shown in Fig. 1 the brake
also connects a similar link of the second controll
system shows a pair of control units I0 and
unit 21.
,
.
II at one station for operation by one pilot to
As shown in Fig. 2 the link I8 is normally
control respectively the brakes I2 and I3 on oppo 50 pushed downwardly by a spring 4I con?ned be
site sides of the plane or aircraft, and a second
tween the bracket 31 and a recess in the top wall
pair of control units I l and I5 which may inde
or cover of the chamber 22 so as to hold one or
pendently control the operation of the brakes I2
both of the valve pistons Il and ll in open posi
and I3.
tion and thus to permit free passage of iluid from
Pressure duid is supplied from a main I6 55 the delivery pipe 2l to or from either of the pipes
drawings in which
2| and 22; When fluid is forced through the con
from its respective control unit to its respective
nector l2 and bore I0 it forces the piston valve
downwardly out of the bore and tilts the lever to
the position shown in Fig. 2 closing valve 33 and,
conversely, when valve 33 is forced downwardly
to open position the lever 38 is tilted to close valve
N. This is the normal position of the apparatus
brake applying means, a lever connecting- said
valves to close one when the other is opened by
fluid pressure, and a fulcrum for said lever mov
able to close both said valves.
nected to the fulcrums of both said master con
trols and means acting on said lever between’said
when the control units are not in “parking” posi
tion.
When the apparatus is set for parking the con
fulcrums to move said fulcrums.
-
«
3. The apparatus of claim 1 in which said mas
ter control has a cylindrical bore for each valve of
said pair in said unit between its open and closed
necting or cross-rod 4,0 is raised to the position
shown in Fig. 3 by means of a lifting rod l2 to
which it is pivotally connected at approximately
'
position.
4: A master control for fluid pressure operated
apparatus which comprises a hollow casing hav
ing an outlet and a pair of axially parallel inlets
its mid point and which in turn is lifted by a
cable 43, one end of which is secured'to the lifting
rod 42 and the other end of which is secured to a
parking lever M. When this lever is' moved to
the position shown in Fig. 3 it raises the lifting
rod l2 and the link 38 and thereby raises the -float
ing lever 36 until each of the piston valves 33 and
M is closed tightly on the lower valve face of its
respective plug 3l or I32. In this; position no fluid
opening into said casing, a rod-like member hav
ing one end extending into the casing, said mem
ber being equidistantly spaced between said in
lets, a lever pivoted on said end, and valves, one
pivotally mounted on said lever within the casing
on each side of the pivot, each valve being posi
tioned to close one of said inlets, said member
being movable parallel to said inlets between a
position wherein each valve is held on its respec
tive inlet and a position wherein the lever and
its associated valves are free to rock about its
can be released from the delivery pipe 24, or 2_8,
and the brakes once applied cannot be released
until the parking lever is moved to the position of
Fig. 2.
_
. 2. The apparatus of claim 1 having a lever con
-
When the plane is to be parked the brakes are
applied by operation of the control units I0 and l I
pivot.
.
HENRY WILLIAM TREVASKIS.
or Il and l5 and the parking lever M' moved to
the position shown in Fig. 3. The pressure ñuid -
REFERENCES CITED
cannot be released from any of the stations I0,
The following references are of record in the
Il, Il or.|5 until the parking lever is moved to
ille of this patent:
the position shown in Fig. 2. Accordingly it is
UNITED STATES PATENTS
impossible to release the brakes inadvertently 35
from their parking condition.
Number
Name
Date
Having described my invention, what I claim is:
1,517,956
Compton _e ________ __ Dec. 2, 1924
1. Fluid control brake apparatus which com
2,024,549
Tarris __________ __ Dec. 17, 1935
prises a pair of brake applying means, two pairs
2,148,268
Kerr ____ -_-_ ..... __ Feb. 21, 1939
is thereupon trapped in the brake system and
of manual control units, one for each brake ap
plying means, to control independently admission
of fluid to, or its release from, said brake apply
ing means, a master control for each brake apply
ing means having a pair of valves, one for each of
said control units, opening under fluid pressure
40
~
Number
427,829
FOREIGN PATENTS
Country~
`
Date
Great Britain _____ __ May 1, 1935
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