WHEEL BRAKE COOLING APPARATUS FOR AIRCRAFT

DISPOSITIF REFROIDISSEUR DES FREINS DE ROUES D'AERONEFS

English Abstract

ABSTRACT


A wheel brake cooling apparatus for aircraft comprises
a clamp assembly (14) for attachment to an aircraft
tyre (12)
a duct (22) with a seal (30) which mates with the
wheel hub (2) and contains an axial flow fan (32),
the duct being suspended from clamp assembly by a
hook assembly (18) fixed to struts (36) which brace
the duct. When activated, the fan draws air through
the wheel brakes and wheel hub preventing tyre damage
after high energy stops.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A wheel brake cooling apparatus for aircraft
comprising a clamp assembly for attachment to an
aircraft tyre,
a duct adapted to be clamped by the clamp assembly
against an aircraft wheel upon which the tyre is
fitted,
and a fan arranged, when activated, to draw cooling
air through the wheel brake assembly via the duct.
2. Apparatus as claimed in claim 1 wherein the
clamp assembly comprises a tyre-straddling, U-shaped
frame with a first tyre engaging pad for one sidewall
of the wheel and a second tyre engaging pad for the
opposite side wall and means to clamp the pads against
the tyre.
3. Apparatus as claimed in claim 2 wherein the frame
is made of a major part, the length of which exceeds the
greatest sidewall to sidewall width of the tyre, which
part carries an inwardly directed pad for engaging one
sidewall and a minor part which is pivoted to the major
part, which minor part carries a complementary pad for
engaging the opposite sidewall and a lever operated
linkage for clamping the pads on the two parts of the
frame to the tyre.
4. Apparatus as claimed in any one of claims 1 to 3
wherein the duct is of circular cross-section and has a
ring seal at the front edge thereof in order to mate with


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the wheel hub.
5. Apparatus as claimed in claim 1 wherein the fan
is an axial flow fan supported in a cylindrical
housing of smaller cross-sectional area than the duct
and the duct extends from the housing on the input
side of the fan.
6. Apparatus as claimed in claim 1 wherein the duct
is releasably attached to the clamp assembly by a hook
assembly which affords pivotal connection between the
frame and the duct, the hook assembly being of adjust-
able length so as to permit the duct to mate closely
with the wheel.
7. Apparatus as claimed in claim 5 or 6 wherein the
duct is made of sheet metal and the mouth of the duct
is braced by struts which extend between the mouth of
the duct and the fan housing and the hook assembly
extends from a cross bar joining a pair of struts to
a cross bar on the minor part of the frame.

Description

BAC~GRO~ND OF THE INVENTION
This invention concerns an aircraft wheel brake
cooling apparatus.
When large aircraft make high energy stops that is
they use perhaps reverse thrust and maximum application
of the wheel brakes the latter heat up considerably and
due to the mass of the brake assembly and associated
wheel and the good conductivity to the aircraft tyre there
follows when the aircraft is at rest a dangerous increase
in tyre pressure which must be relieved. Defla-tion of
the tyres is hazardous because of the possibility that the
two bolted halves of the wheel may burst apart while
deflation is being attempted.The brakes may not cool to
ambient for two hours.
If the aircraft IS scheduled to take off shortly
after landing which is common on short routes the brakes
wiil De subject to a further application before cooling
adequately from the high energy stop.
OBJECTIVE AND SUMMAR~ OF THE INVENTI~N
This ir~ention seeks to prov~de an apparatus which red~ces
the risk of damage to the wheel and tyre by overheating
during the period following a hiyh energy stop.
This invention provides a wheel brake cooling
apparatus for aircraft comprising a clamp assembly for
attachment to an aircraft tyre,
a duct adapted to be clamped by the clamp assembly
against an aircraft wheel upon which the tyre is fitted,




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and a fan arranged, when activated, to draw cooling
air through the wheel brake assembly via the duct.
A clamp assembly may comprise a tyre-straddling,
U-shaped frame with a first tyre engaging pad for one
sidewall of the wheel and a second tyre engaging pad
for the opposite side wall and means to clamp the pads
against the tyre. The frame may be made of a major part,
the length of which exceeds the greatest sidewall to
sidewall width of the tyre, which part carries an inwardly
directed pad for engaging one sidewall, a minor part which
IS pivoted to the major part, whlch minor part carries a
complementary pad for engaging the opposite sidewall and a
lever operated linkage for clamping the pads on the parts
of the frame to the tyre. The duc~ may be of circular cross-

sec~ie~ and may have a ring seal at the front edgethereof in order to mate with the wheel hub. Preferably the
fan is an axial flow fan supported in a cylindrical housing
of a smaller cross-sectïonal area than the duct and the duct
may extend from the housing on the input side of the fan.
The duct may be releasably attached to the clamp assembly by
a hook assembly which affords pivotal connection between
the frame and the duct, the hook assembly being of adjustable
length so as to permit the duct to mate closely with the
wheel.
~5 BRIEF DESCRIPTION OF DRAWINGS
.
One embodiment of the invention is now described by way
of example with reference to the accompanying drawings
wherein


Fig. 1 is a diagrammatic section of the apparatus
and the aircraft wheel to which it is applied
Fig. 2 is a side view of the clamp assembly
Fig. 3 is a plan of the clamp assembly.
S DESCRIPTION OF PREFERRED EMBODIMENT
Referring to Fig. l, the aircraft wheel has two hub
sections 2, 4 clamped together by bolts 6. A multiple
disc brake assembly 8 is located within hub section 4.
Hub section 12 is pierced by cut-outs 10. The wheel
10 supports a tyre 12~ A frame 14 straddles the tyre 12
~ .
and crossbar 16 thereon supports a hook assembly 18 which
is welded to the struts 20 of the duct 22. The duct is
a sheet aluminium frustrum whîch coaxially overlaps an
aluminium motor housing 24 the open end of which is
protected by a grid 26. The ~nlet end of the frustrum
has a rolled edge 28 which is protected by a rubber seal 30.
An a~ial flow fan 32 IS mounted wIthin the housing 24 on
arms 34 ~only one shown) and is supplied with 115v DC from
a ground supply or from the a~rcraft generators. The fan
produces a flow of 1400 cfm. The duct is stiffened by six
tubular struts 36. The hook assembly 18 welded to the
upper pair of struts consists of two slotted plates 38
which locate a pin 40 and a pair of tubes 42 each provided
with adjustable screws 44 and hooks 46 for engaging cross
bar 16.
Referring now to Figs. 2 and 3 the clamping frame 14
consists of a Major tubular part 48 provided with a pair of



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pads 50 which abut a sidewall of the tyre 12. A minor
part 52 of the frame carries complementary pads 54. The
major and minor parts of the frame are pivotally connected
by pins 56, 58 and normally urged into a clamping position
by spring 60 but are openable by use of the lever and linkage
62. After a high energy stop the discs may reach 850 F.
The clamp assembly is fitted to the tyre and the duct sealed
to the wheel. Air is drawn through the cut outs creating an
air stream over the discs which cool rapidly in the first
five minutes. Twenty minutes is generally required to reduce
the wheel mass to ambient.
We have found the advantages of the apparatus to be
1.: Ease of use due to lightness of construction
2. Adaptability to different sizes of tyres
3. The apparatus can be applied from positions fore
and aft of the wheel so that personnel need not stand in
line with the direction of separation of the h~bs.
4. The rapid cooling reduces the risk of distortion
in the brakes.




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