Note: Descriptions are shown in the official language in which they were submitted.
TIRE INFLATION VALVE
HAVING OVERPRESSURE ,~ND FLON CONTROL 1 3 3 2
BACKGROUND OF THE INVENTION
Naintenance of adequate pressure in pneumatic tires is
acknowledged as a critical requirement. In particular, high
performance tires used on the wheels of modern aircraft of
large size and heavy weight, which land at high ,3peeds have
a critical requirement for accurate tire pressure.
In practice, in the maintenance of aircraft and other
vehicles employing pneumatic tires such as highway trucks,
and off the road vehicles, it i8 difficult and in some cases
impossible to provide a regulated source of pressurizing gas
to prevent over inflation. Also, high performance tires are
oft~n inflated with nitrogen in order to reduce the
lS oxidation of such tires at high temperatures. Nitrogen is
further preferred because of the relatively large size of
its molecule, in comparison to the other constituents of -~
air, which reduces tire leakage. A convenient and economic
source of nitrogen is a high pressure tank wherein the
delivered nitrogen is regulated from a typical tank pressure
of 3,000 P.S.I.G., down to a tire delivery pressure, which
typically is 300 P.S.I.G.
However, conventional tank regulators are of~en ~;
inaccurate in regulated output pressure, or fail to control
delivery~ flow, or in many ca,ies limit the delivery flow to
low values that result in excessive inflation time. Also in
many cases, it is exigent to utilize unregulated sources,
such as secondary~ tank, filled to an intermediate pressure
from a primary source. These secondary tanks are in co~mon
use and are economical, convenient and normally do not have
an attached regulator. Tire filling or pressurization from
an unregulated, secondary tank i8 essentially a cut and try
operation. The usual technigue involves approaching a
desired pressure by gauging and filling in small steps.
Since individual filling steps are by #feel n ~ over
pressurization can easily occur.
The avoidance of over pressurization is critical -~
because it can cause excessive tire wear, 108,5 of structural
integrity and in extreme cases explosive failure. In many
cases these explosions have caused ~erious in~ury and de~th ~`
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to attending personnel. Unfortunatelyj the correct
inflation pressure varies from vehicle to vehicle, and
varies with location on a vehicle. Therefore, if a
regulator is present on the pressure source, it constantly
must be adjusted. Every time a regulator is ad~usted, there
is a chance that it will be improperly ad~usted.
In view of the above mentioned difficulties, it is
desireable to provide means to accurately regulate flow and
delivery pre~sure for each individual tire. In this way
correct inflation is assured.
These difficulties including Fiafety related
difficulties encountered with presently used tire
pressurizing valves are overcome through the use of
Applicants' invention. As disclosed, Applicants' invention
provides a small, light weight and economical self-contained
pressure and flow limiting valve as a replacement for the
conventional tire valve. In use, the valve of the invention
provides pressure relief and limits flow there through when
in the relief position through positive shutoff, providing a
convenient means for rapidly maintaining tire pressure from
unregulated sources.
It is therefore an object of this invention to provide ~-
a pneumatic tire pressurization valve incorporating pressure
relief at a predetermined pre~sure setting along with
further overpressure protection through flow limiting and
positive shutoff of the pressurizing gas when in the valve
i8 in its relief position.
It is an additional ob~ect of this invention to provide
a pneumatic tire fill valve having size, weight, and cost
features which allow permanent mounting on individual tires~
thereby providing automatic control of tire pressurization
without the need for a separate tire gauging operation.
It i8 a further ob~ect of this invention to provide a
mall, lightweight and economically designed tire fill valve
directly replacing the individual original tire valve,
wherein correct tire pressure can be assured even when the
tire fill gas source is of substantially greater pressure
and flow capacity than the tire and the valve respectively.
It is yet an additional object of this in~ention to
reduce the danger to maintenance personnel, engaged in
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~-- pressurizing a high pressure pneumatic tire from a source
having exces6ive pressure and flow capacity, through the use
of a pressure and flow limiting valve continuou~ly attached
to the tire. -
5 SUMNARY OF THE INVENTION -
The invention disclosed herein is a small, lightweight,
economical tire fill valve of 6uch 6ize and weight that it
can be permanently attached to the rim of a tire wheel
having a pneumatic tire mounted thereon. Pressurizing gas
from a source of high pressure and/or high flow capacity i8
admitted at the inlet of the valve through the usual spring
loaded poppet type inlet valve, commonly known to the
pneumatic industry as a Schrader valve. Pressurizing gas,
which is admitted through the Schrader valve by the
15 depression of it6 inlat or operating rod by a typical air -~
chuck, passes through a flow limiting orifice containing a
flow actuated poppet before entering a pressure sensitive
chamber. The pressure sen6itive chamber i6 in constant
fluid communication with the tire interior. Also in fluid
20 communication with the pressure 6ensitive chamber via a ~ -~
; multiplicity of orifices having a semicircular segmental
cross section, i6 a valve disk. The valve disk cooperates
with a vslve seat to normally seal an exhaust passage. The
valve disk is force biased against the valve seat by a `~
series of spring washers which produce a preload force. The
spring washers having a limited travel also limit lifting
travel of the valve disk at a predetermined chamber
pressure.
Nhen the pressure sensitive chamber reaches a pressure
wherein the valve disk force approaches that of the spring
washers, vertical movement or lifting of the valve disk ~ ~'
aIlows gas flow from the chamber to exit ~he valve through
~`' an additional multiplicity of segmental relief passages ;,;~
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- and/or vents arranged in a circular pattern circumferential
of the inlet valve.
In operation, as the tire pre~6ure reaches the value
determined by the force balance 6ystem, consisting of the
valve disk and the spring washers, any increase in tire
pressure above a predetermined value is prevented by disc
lit and venting of the fill gas. In cases where ga~
sources having extremely high gas delivery are in u~e,
overpressurization of the pressure sensitive chamber is
prevented since exce6s flow through the flow limiting
orifice is prevented by positive shutoff of flow sensitive
poppet contained in the flow limiting orifice.
BRIEF DESCRIPTION OF THE D~AWINGS
Other ob~ects and advantages of the invention will
become apparent upon reading the following detailed
description and indicated reference to the drawings, in
which:
Figure 1 is a side view of the finished valve, shown
essentially full size. In particular, the upper or inlet
valve, and the lower or tire attachment adapter are shown
along with a hexagonal installation shoulder.
Figure 2 iB a cross-sectional view of the valve of the
invention along the line 2-2 of Figure 1 (inlet cap ~i
omitted). Figure 2 particularly shows the valve of the
invention in its tire fill and non-relief position.
Figure 3 is a partial section at the line 2-2 of Pigure
1, showing the valve of the invention in overpressure and
overflow relief position, particularly showing the flow
sensitive poppet in positive shutoff.
Figure 4 is an additional section along the line 4-4 of
Figure 2, particularly showing the semi-circular segmented
or arcuate upper relief pa~sage~ of the valve of the
invention.
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Figure S is a ~ection of the valve of the invention
along the line 5-5 of Figure 2, particularly showing the
semi-circular segmented or arcuate lower relief ports. ~-~
Figure 6 i8 a partial enlarged section of the valve of
the invention along line 2-2 of Figure 1, particulsrly
showing the gas lnlet adapter and flow sensitive poppet, in
a fill and non-relief position.
While the pneumatic pressurization valve of this
invention will be described in connection with a preferred
embodiment, it is understood that the preferred embodiment
is not intended to limit the invention to that embodiment. ~`
On the contrary it is intended to cover all alternatives,
modifications, and equivalents as may be included within the
spirit and scope of the invention as defined by the appended ~ ;
15 claims. -~
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DETAILED DESCRIPTION OF THE INVENTION
With particular reference to Figures 1 and 2, there i8 '
; shown a pressure and flow relieving tire inflation or ~
20 pressurization valve 10 of the invention having a gas ~f
~- pressurization inlet 12 and a tire adapter and outlet end
14. The valve 10 al80 incorporates a hexagonal portion 16 l;
having safety or retention wire holes or ports 18 in keeping
with commonly used wire antiturn techniques in u6e in the `-
aircraft and/or automotive industries.
With particular reference to Figure 2, the tire
pressurization and relief valve 10 includes an outer shell ;~
~ or housing 20. Internal of the outer shell or housing 20 at ~; ;
;~ its inlet end 22 is the hexagonal portion 16 suitable for
proper installation, and a gas inlet adapter 24. ~he outer
shell 20 further includes at its outlet end 14, a threaded
outlet or tire adapter 26 having an outlet port 28 suitable
for direct mount~ng on the rim inlet of the wheel mounting a ;~
pressurized pneumatic tire (not shown). Intermediate of the
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outlet port 28 and gas inlet adaptex 24 i~ a valve spool 30
incorporating a spool spring chamber and/or relief passage
32 that contains an annular spring and/or spring washers 34
and an annular valve disk 36. The spring washer~ 34 and
valve disk 36 are concentric with and cixcumferentially
disposed around a lower cylindrically shaped portion 38 of
the gas inlet adapter 24.
A lower portion 40 of the valve spool 30 further
incorporates a plurality of segmental, semi-circular flow
passages or orifices 42 each having a raised lip seat 44
facing a concentric valve disk seal 46 for sealing
cooperation therewith.
The lower ends 48 of the lower relief passages 42
defined by the valve spool 30 terminate in a pressure
sensing chamber 50 further defined by the lower portion 40
of the valve spool 30 and the upper 6urface 52 of a
deflector disk 54. The upper surface 52 of the deflection
disk 54 forms the lower surface of the pressure sen~ing
chamber 50 and includes tire fill ports 58 passing
therethrough. The fill ports 58 fluid communicate the
pressure sensing chamber 50 and the interior of the tire to
be filled via the valve outlet port 28. A suitable pressure
seal 60 i8 positioned between the valve housing 20 and the
lower corners 62 and 64 of the valve spool 30, and deflector ;~
disc 54 respectively.
As indicated above, internal and of surrounded by the
hexagonal portion 16 and valve spool 30 is a gas inlet
adapter 24. The adapter 24 includes a valve inlet port 66
having external threads 68 for incorporation of a dust cover
or additional leak preventing cap 70 (reference Figure 1).
The inlet port 66 threadably engages a tire fill valve 72 of
a conventional type, commonly known as a "Schrader~ valve
having its inlet 74 ad~acent the inlet port 66 and it8
outlet 76 internal of the gas inlet adapter flow passage or
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cavity 78. The lower end 80 of the flow passage 78 defines
and/or i8 terminated by a control orifice 80 80 that g~s
pressure communicates between the passage or cavity 78 and
the pressure sensing chamber 50.
As shown in Figure 6, a flow sensitive poppet 84 i~
mounted in the flow pa~sage 78. The poppet stem 86 is
centrally maintained in longitudinal alignment with the
lower base 88 of the inlet adapter pa~sage 78. A conical
spring 90 provides al~gnment and vertical preload force to
the poppet 84, maintaining the poppet closure end 92 with
its alignment pin 94 above a cooperating seat 96.
Also internal of the housing hexagonal portion 16 i8 a
plurality of concentrically disposed fill gas exit ports 98 ::.
each having a semi-circular arc like cross Rection. The
15 exit ports 98 fluid communicate the ~pool spring chamber 32 ..
with ambient air. An annular circular dust cover 100 of
flexible elastomeric material such as natural rubber or ':~
neoprene provides protection to the ports 98 from external
contamination, readily allowing venting of the pressurizing
gas during relief operation of the valve 10.
In operation, gas from a high pressure and/or high : :
capacity source is introduced through a conventional air
chuck (not ~hown) having a deflector tongue for depressing
the inlet or Schrader valve actuating pin 102. As those
skilled in the art will readily recognize, operation of the
Schrader valve 72 i8 such that depressing the pin-102 moves
the lower member or poppet 104 vertically downwardly,
opening a concentric port (not shown) internal of the
Schrader valve 72, and admitting pres~urized fill ga~ to the
upper end of gas.inlet adaptex flow passage or chamber 78.
` ! Under fill conditions at pressures below valve calibration
as shown in Figure 2, the pressurization gas flows through
the chamber 78, seat 96, and the flow control orifice 82
into the pre~sure sen~ing chamber 50 through the tire fill
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ports 58 and into the tire to be inflated through the outlet
port 28.
At the completion of the filling process, or for any
other reason when the pres~ure in chamber 50 reaches a value
which act6 on the under~ide 106 of the valve di~k 36 via the
orifices 42 in the valve spool 30 to exceed the
predetermined preload of the ~pring washers 34, the disk 36 ~ :
lift6, as indicated in the right-half portion of Figure 3,
allowing relief flow of the pres6urizing gas to exit the
valve 10 via the 6pring chamber 32 and exit ports 98. As
discussed above, the flexible dust cover 100 i6 easily
deflected by the exiting gas and as shown in the right-half
of Figure 2, allows easy venting. Venting of the fill gas ~;
: under relief conditions limits the pressurization of the ~:
tire being filled to a predetermined value. Typically~ fill
pressure is limited to 300 P.S.I.G. and hence the pressure
causing lifting of the disk 36 is 300 P.S.I.G.
: A highly important feature of the disclosed invention :
arises from the fact that under conditions where the fill
source pressure and/or capacity for one reason or another is
a multiple or even an order of magnitude greater than the ::
desired tire maximum, venting of a conventional relief
device would still result in over pressuring of the tires
since the restricted flow through the exit ports 98 would
25 not limit the pressure possible in the chamber 50
sufficiently to prevent overpressure from existing at the
tire inlet or valve outlet port 28. However, Applicants
have discovered that inclusion of the flow sensitive poppet :~
~: 84, maintained in an open or flowing position as shown in
30 Figures 2 and 6, where the poppet 84 is maintained away from
" bhe valve $eat 96 by the preload or bias force of the
conical spring 90, controls tire filling gas flow through :~
said seat 96 for both relief and normal flow conditions of ~ ~;
~: the valve 10. ~ ~i
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In operation, ~hould fill pressure in chamber 50 exceed
a predetermined relief pressure, venting fill gas through
ports 98 reduces filling gas pressure entering the tire at
the outlet port 28. However if the pressure differential
5 between the poppet 84 and the outlet port 28 i8 too high, ;
venting through ports 98 may be insufficient to hold the
pressure in chamber 50 below a predetermined value, ~-
typically 20~ in excess of the desired tire pressure. In -~
this instance, the poppet 84 contained in the flow pas~agei ;~
10 i8 of the gas inlet adapter 24, moves downwardly due to the ~-
flow induced pressure drops across the poppet head 108,
thereby contacting the seat 96 and reducing the pressure
within the chamber 50 and the flow into the tire through the
outlet port 28. Control of the downward motion of the
poppet 84 and the quantity of flow past ~he seat 96 i8 aided
by the flow drag of peripheral grooves 110 in the poppet
head 108. An alignment pin 112 extending from the poppet
104 into the poppet head 108 centers the head 108 in the ;
flow passage 78.
Thus it ~ apparent that there has been provided in
accordance with the invention the tire fill valve that fully
satisfies the ob~ects, aims and advantages as set forth
above. While the tire fill valve disclosed here has been
described in con~unction with specific embodiments thereof,
25 it i8 evident that in the alternativeæ modifications end -~
variations will be apparent to those skilled in the art in
the light of the foregoing description. Accordingly it i~
intended to e~brace all such alternatives, modifications and
variations as fall within the spirit and broad scope of ~he
30 appended claims. `
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