VEHICLE TIRE DEFLATION SIGNALLING SYSTEM

SYSTEME AVERTISSEUR DE DEGONFLEMENT DE PNEUMATIQUES

English Abstract

ABSTRACT OF THE DISCLOSURE

The invention is directed to means adapted for connection
to a gaseous fluid container for visually signalling a reduct-
ion of pressure in the container, for example a vehicle tire,
to indicate a decline or diminution of fluid in the container,
to enable an observer to initiate steps for restoring the
desired pressure when the presseure of the gaseous fluid in the
container is diminished for any reason below a predetermined
minimum desired pressure.

Claims

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

1. Vehicle tire deflation signalling system comprising
a substantially cylindrical housing having an axial bore and
adapted for securement to the tire with one end of said bore in
communication with the interior of the tire, said housing pre-
senting an annular valve seat facing toward said end of the
bore, an annular shoulder facing toward said end more remote
therefrom than said valve seat, and an annular sealing surface
converging toward the opposite end of the bore more remote from
the first end thereof than said shoulder, a valve poppet in the
bore engageable with said annular seat and adapted to be biased
thereagainst by fluid under pressure in the tire, yielding
means disposed in the bore in engagement with said shoulder and
said poppet biasing the poppet toward the tire and away from
said annular seat, a substantially cylindrical indicating unit
disposed in the bore adapted to be projected beyond the end
thereof remote from the tire upon release of gaseous fluid from
the tire by said poppet, resilient annular sealing means sur-
rounding said indicating unit and engageable with said converg-
ing annular sealing surface to confine within the bore gaseous
fluid released thereinto by movement of the poppet away from
its seat under bias of said gaseous fluid under pressure in the
tire, and yielding means biasing the indicating unit in the
bore in the direction to maintain said sealing means in engage-
ment with said sealing surface.

2. A signalling system as defined in Claim 1 in which
a spindle is carried by said indicating unit extending there-
from axially in the housing toward the poppet and engageable
therewith to displace the poppet from its seat.





3. A signalling system as defined in Claim 1 in which
a spindle is interposed between the indicating unit and the
poppet and is movable axially in the housing to unseat the
poppet in response to axial movement of said unit toward the
poppet.


4. A valve for normally confining a gaseous fluid in a
container comprising a tubular housing, a substantially annular
valve seat in the housing coaxial therewith, a valve poppet in
the housing biased by the gaseous fluid in the container into
sealing engagement with the valve seat, piston plunger means
movably contained in said housing, an end of said plunger extend-
ing through an open end of said housing remote from said valve
seat, seal means on said plunger end operatively coactible with
said housing proximate said open end, said valve poppet and
said seat constituting a first seal to prevent gas escape from
said container, said plunger end and seal means constituting a
secondary gas escape prevention means.


5. A valve for normally confining a gaseous fluid in a
container comprising an elongated tubular housing, a sub-
stantially annular valve seat in the housing, coaxial there-
with, said valve seat is proximate an end of said tubular hous-
ing operatively connected to said container, a valve poppet in
the housing biased by the gaseous fluid into the container into
sealing engagement with the valve seat and constituting there-
with primary seal means for prevention of escape of said gaseous
fluid from said container, a piston assembly movably contained
in said tubular housing and disposed therein beyond said valve

seat toward an opposite, open end of said tubular housing, said
piston assembly being operable upon a decrease of the bias on
said valve poppet to sealingly engage in said open end and




constituting therewith secondary seal means for prevention of
gaseous fluid escape from said container.

6. A valve as claimed in Claim 5, including first
spring means in said housing operatively engaged with said
poppet valve and operable upon a decrease of pressure of the
gaseous fluid in the container to overcome bias of the valve
poppet by the gaseous fluid in the container to disengage said
valve poppet from said valve seat whereupon gaseous fluid under
pressure will engage a portion of said piston assembly and move
the same outwardly with respect to said opposite open end of
said housing and thereby operatively activate said secondary
seal means in said housing.


7. A valve as claimed in Claim 6, said spring compris-
ing a compression spring and having a strength for movement of
said poppet upon decrease of pressure of the gaseous fluid in
said container below a predetermined value.


8. A valve as claimed in Claim 7, a spacing washer
disposed within said tubular housing intermediate the ends
thereof, an end of said compression spring opposite an end
thereof engageable with said poppet valve being operatively
engageable with said spacing washer.


9. A valve as claimed in Claim 8 and including a
return spring in said tubular housing disposed intermediate
said spacing washer and said piston assembly, said return

spring being operable to return said piston assembly to a
closed sealing engagement with said open end following an
operative depression of said piston assembly with respect to
said opening, for the purpose of gauging gaseous fluid pressure
in said container, and for venting or adding to the gaseous



medium in said container.

10. A valve as claimed in Claim 9, said tubular housing
having internal chambers therein of decreasing diameter from
said spacing washer to said open end, the smaller diameter
chamber terminating proximate to said open end and including
an annular seat disposed therebetween, said piston assembly
including an annular low pressure indicator head extendable
through said open end and a signalling piston axially spaced
therebelow, an annular groove between said indicator head and
said signalling piston, an O-ring seal in said groove, said O-
ring being sealingly engageable in said opening with said piston
assembly in retracted position wherein said signalling piston is
contained within the smaller diameter chamber, said O-ring pre-
venting entrance of contaminants into said tubular housing under
normal operating pressures of gaseous fluid in said container.

11. A valve as claimed in Claim 10, said piston
assembly including an annular piston spaced from said signalling
piston and having an annular groove therebetween, an O-ring seal
in said latter groove, said latter O-ring being engageable with
a valve seat formed by the merging area between said smaller
internal chamber and said opening and constituting said
secondary seal means.


12. A valve as claimed in Claim 11, a guide spindle
connected to the second larger said piston and extending within
said tubular housing, through said return spring, said spacing
washer and into said compression spring, said guide spindle

being operable to contact said poppet upon depression of said
piston assembly to disengage the poppet from its seat and
creating an air flow passage through said tubular housing from

11


said container to said open end thereof, said return spring
being operatively engageable between said larger piston and
said spacing washer in the depressed position of said piston
assembly.


13. A valve as claimed in Claim 11, wherein the
internal diameter of the outer of said chambers and the exterior
dimensions of said O-ring disposed intermediate said pistons
being substantially equal and in slidable sealing engagement
upon movement of said O-ring therethrough to the closing sealing
position constituting said secondary seal means.


14. A valve as claimed in Claims 4, 5 and 13, said
valve constituting a vehicle tire deflation signalling system,
said valve being operatively attached to a vehicle tire rim of
a vehicle wheel, the lowermost end of said tubular housing
extending through the rim and the bottom thereof being in open
communication with the interior of a said vehicle tire, the
means constituting the first seal being disposed within the
tire, the upper portion of the housing extending outwardly above
the rim and containing the means constituting the secondary
seal to prevent gas escape upon a decrease of air pressure with-
in the tire.


15. A composite valve and visual fluid pressure loss
indicator device for a container having a fluid medium under
pressure therein, said device including a housing having a bore
therethrough, said bore terminating in open ends, a first of
said open ends being operatively and openly engageable with the

interior of said container, said bore being formed as a plura-
lity of interconnecting chambers of decreased diameter from
said first open end toward a second said open end, moveable

12


closing and sealing means in said bore, a poppet chamber at said
first said end in communication with said bore, said sealing
means including a spring biased closing poppet member opera-
tively contained in said poppet chamber, and engageable with
an end of said bore to close and seal said bore against fluid
passage therethrough with a predetermined pressure in said
container, and constituting a first sealing closure, said move-
able means further including piston means in said bore, said
piston means mounting an O-ring thereon, one said bore chamber
proximate said first open end, having a restricted outlet open-
ing and constituting, in conjunction with said O-ring, a second
sealing closure operable upon a decrease of fluid pressure in
said container to release the spring biasing of said poppet
member and permit movement of said moveable means to a closure
sealing position with an interengageable seat proximate said
second said open end.


16. A composite valve as claimed in Claim 15, said
container comprising a vehicle tire, a rim mounting said tire,
said rim having an opening therethrough, the lower end of said
housing extending through said opening into the interior of
said tire, said housing being operably secured to said rim, the
means comprising said first sealing closure being disposed
interiorally of said tire and the upper portion of said housing
extending above said rim and said second sealing closure being
disposed above said rim, said moveable means being extendable
through said second said open end of said housing at said pre-
determined pressure and constituting a visual indicator extend-
ing above said housing.

13

17. A valve for normally confining a gaseous fluid in a
container comprising an elongated tubular housing, a spacing
washer disposed within said tubular housing intermediate the
ends thereof, said tubular housing having internal chambers
therein of decreasing diameter from said spacing washer to said
open end, the smaller diameter chamber terminating proximate
to said open end and including an annular seat disposed there-
between, said valve seat being proximate an end of said tubular
housing operatively connected to said container, a valve poppet
in the housing biased by the gaseous fluid in the container
into sealing engagement with the valve seat and constituting
therewith primary seal means for prevention of escape of said
gaseous fluid from said container, a compression spring in
said housing operatively engaged with said valve poppet and
operable upon a decrease of pressure of the gaseous fluid
in the container to overcome bias of the valve poppet by the
gaseous fluid in the container to disengage said valve poppet
from said valve seat, a piston assembly movably contained in
said tubular housing and disposed therein beyond said valve
seat toward an opposite open end of said tubular housing, said
piston assembly including an annular low pressure indicator
head extendable through said open end and a signalling piston
axially spaced therebelow, an annular piston spaced from said
signalling piston and having an annular groove therebetween,
an O-ring seal in said annular groove, said O-ring being
engageable with a valve seat formed by the merging area between
said smaller internal chamber and said opening and constituting
said secondary seal means, said piston assembly being operable
upon a decrease of the bias on said valve poppet to sealingly
engage in said open end and constituting therewith said
secondary seal means for prevention of gaseous fluid escape
from said container, an end of said compression spring opposite


the end thereof operatively engaged with said poppet valve
being operatively engageable with said spacing washer, a
return spring in said tubular housing disposed intermediate
said spacing washer and said piston assembly, said return
spring being operable to return said piston assembly to a
closed sealing engagement with said open end following an
operative depression of said piston assembly with respect to
said opening, for the purpose of gauging gaseous fluid
pressure in said container, and for venting or adding to the
gaseous medium in said container.


18. A valve for normally confining a gaseous fluid in a
container comprising an elongated tubular housing, a spacing
washer disposed within said tubular housing intermediate the
ends thereof, said tubular housing having internal chambers
therein of decreasing diameter from said spacing washer to
said open end, the smaller diameter chamber terminating proxi-
mate to said open end and including an annular seat disposed
therebetween, said valve seat being proximate an end of said
tubular housing operatively connected to said container, a
valve poppet in the housing biased by the gaseous fluid in
the container into sealing engagement with the valve seat and
constituting therewith primary seal means for prevention of
escape of said gaseous fluid from said container, a compression
spring in said housing operatively engaged with said valve
poppet and operable upon a decrease of pressure of the gaseous
fluid in the container to overcome bias of the valve poppet by
the gaseous fluid in the container to disengage said valve
poppet from said valve seat, a piston assembly movably contain-
ed in said tubular housing and disposed therein beyond said
valve seat toward an opposite open end of said tubular housing,
said piston assembly including an annular low pressure indicat-

or head extendable through said open end and a signalling



(claim 18 continued)
piston axially spaced therebelow, seal means sealing the open
end of said tubular housing preventing entrance of contamin-
ants into said tubular housing under normal operating
pressures of gaseous fluid in said container, said piston
assembly being operable upon a decrease of the bias on said
valve poppet to sealingly engage in said open end and con-
stituting therewith said secondary seal means for prevention
of gaseous fluid escape from said container, an end of said
compression spring opposite the end thereof operatively
engaged with said poppet valve being operatively engageable
with said spacing washer, a return spring in said tubular
housing disposed intermediate said spacing washer and said
piston assembly, said return spring being operable to return
said piston assembly to a closed sealing engagement with said
open end following an operative depression of said piston
assembly with respect to said opening, for the purpose of
gauging gaseous fluid pressure in said container, and for
venting or adding to the gaseous medium in said container.

16

19. A valve for normally confining a gaseous fluid in a container
comprising A unitary elongated tubular housing having an open end, a spacing
washer disposed within said tubular housing intermediate the ends thereof,
said tubular housing having internal chambers therein of decreasing diameter
from said spacing washer to said open end, the smaller diameter chamber
terminating proximate to said open end and including an upper chamber seat
disposed therebetween, a substantially annular valve seat being proximate an
end of said tubular housing operatively connected to said container, a valve
poppet in the housing biased by the gaseous fluid in the container into
sealing engagement with said valve seat and constituting therewith primary
seal means for prevention of escape of said gaseous fluid from said container,
a compression spring in said housing operatively engaged with said valve
poppet and operable upon a decrease of pressure of the gaseous fluid in the
container to overcome bias of the valve poppet by the gaseous fluid in the
container to disengage said valve poppet from said valve seat, a piston
assembly movably contained in said tubular housing and disposed therein beyond
said valve seat toward an opposite open and of said tubular housing, said
piston assembly including an annular low pressure indicator head extendable
through said open end and a signalling piston axially spaced therebelow, an
annular groove between said indicator head and said signalling piston, a first
0-ring seal in said groove, said first 0-ring seal being sealingly engageable
in said open end with said piston assembly in retracted position wherein said
signalling piston is contained within the smaller diameter chamber, said first
0-ring seal preventing entrance of contaminants into said tubular housing
under normal operating pressures of gaseous fluid in said container, said
piston assembly being operable upon a decrease of the bias on said valve
poppet to sealingly engage in said open end and constituting therewith
secondary seal means for prevention of gaseous fluid escape from said
container, an end of said compression spring opposite the end thereof
operatively engaged with said poppet valve being operatively engageable with
said spacing washer, a return spring in said tubular housing disposed
intermediate said spacing washer and said piston assembly, said return spring
being operable to return said piston assembly to a closed sealing engagement
with said upper chamber seat following an operative depression of said piston
assembly with respect to said opening, for the purpose of gauging gaseous

17


fluid pressure in said container, and for venting or adding to the gaseous
medium in said container.
20. A valve as claimed in claim 19, said piston assembly including an
annular piston spaced from said signalling piston and having an annular groove
therebetween, a second O-ring seal in said latter groove, said second 0-ring
being engageable with said upper chamber seat formed by the merging area
between said smaller internal chamber and said opening and constituting said
secondary seal means.
21. A valve as claimed in claim 20, a guide spindle connected to said
piston assembly and extending within said tubular housing through said return
spring, said spacing washer and into said compression spring, said guide
spindle being operable to contact said poppet upon depression of said piston
assembly to disengage the poppet from its seat and creating an air flow
passage through said tubular housing from said container to said open end
thereof, said return spring being operatively engageable between said piston
and said spacing washer in the depressed position of said piston assembly.
22. A valve as claimed in claim 20, wherein the internal diameter of the
outer of said chambers and the exterior dimensions of said second O-ring seal
disposed intermediate said pistons being substantially equal and in slidable
sealing engagement upon movement of said second 0-ring seal therethrough to
the closing sealing position constituting said secondary seal means.
23. A valve and low-pressure indicator assembly for a pressurized
container comprising:
(a) a tubular housing having a downwardly-facing seat:
(b) a valve poppet cooperating with the seat;
(c) spring means biasing the valve poppet away from the seat, the
spring means being overcomeable by air pressure within the tire above a
preestablished pressure;
(d) mounting means intermediate the level of the seat and the upper
end of the housing for mounting the valve assembly to the pressurized
container;
(e) said poppet and seat being located and protected inside the
pressurized container;
(f) an indicator piston reciprocable in the housing and having an
upper portion adapted to be seen and indicate low pressure, the piston having

18

an upper position for indicating, a lower position for venting and B normal
position intermediate the two, the piston having a downward extension adapted
to engage the poppet and forcibly open it when the piston is moved manually
down to the lower position, the piston sealingly engaging the wall of the
housing except in the venting position;
whereby when the pressure in the container drops, the poppet opens and the
piston is driven to indicating position and whereby from the upper end of the
housing the container may be vented by pressing down the piston to open the
poppet, and gauged or filled by placing a gauge or filling chuck over the top
of the housing and pressing the piston down to open the poppet.
24. A valve and low-pressure indicator as claimed in claim 23 including
sealing means sealing the piston to the wall of the housing except when the
piston is lowered to the venting position.
25. A valve and low-pressure indicator as claimed in claim 23 wherein
second spring means bias the piston toward its normal position.
26. A valve and low-pressure indicator assembly for a pressurized
container comprising:
(a) a one-piece tubular housing having mounting means intermediate
its ends for mounting said housing in an opening in a wall of the container;
(b) a valve seat in the lower end of said housing below the mounting
means;
(c) a valve poppet disposed closer to the lower end than the seat
and movable between a closed position engaging said seat when the pressure in
the container is at least a preestablished pressure to prevent flow through
the housing and an open position permitting flow through the seat;
(d) said poppet and seat being located and protected inside the
pressurized container;
(e) an indicator piston axially movable in said tubular housing
above the valve poppet;
(f) inward shoulder means inside the housing between the valve
poppet and piston;
(g) biasing means in said housing compressively disposed between the
valve poppet and the inward shoulder means and operable upon the existence of
pressure of the fluid in the container below said preestablished pressure to
move said valve poppet to said open position so that pressure enters the

19

housing and drives said indicator piston from its normal position axially
toward the upper end of said housing to a position wherein a portion of the
indicator piston protects upward to indicate visually said lower pressure
condition;
(h) sealing means surrounding the piston to sealingly engage the
wall of said housing and normally prevent leakage of fluid through the
housing, the wall of the housing being configured to permit passage of air
around the sealing means when the piston is below the normal operating
position of the piston, said piston being manually movable toward said valve
poppet and having a downward extension adapted to engage and open the valve
poppet at a position below the normal operating position of the piston; and
(i) second biasing means biasing the piston up to its normal
position following a manual depression and release of said piston
whereby when the assembly is mounted in the container, the seat and poppet are
disposed inside the container protected from damage, and whereby because of
the downward extension of the indicator piston, the poppet may be opened for
gauging venting and filling the container.
27. A valve and low-pressure indicator assembly as claimed in claim 26
wherein the sealing means is an O-ring disposed about the piston.
28. A valve and low-pressure indicator assembly as claimed in claim 26
wherein the container is a vehicle tire.
29. A valve and low-pressure indicator assembly as claimed in claim 26
wherein the configuration of the housing wall is an outward flaring below the
normal operating position of the piston.
30. A valve and low-pressure indicator assembly as claimed in claim 26
wherein the second biasing means is an axial spring which surrounds the
downward extension and extends upward from the shoulder means to the piston.

Description

I ~ 70922
BACKGROUND OF THE INYENTION


The signalling means of the present invention utilizes
some of the underlying principles employed by apparatus as
disclosed in my prior U.S. Letters Patents 3,717,845, 3,827,393
and 3,828,149. The present invention includes differences
over said prior apparatus. In the present invention, the
gaseous fluid under pressure released from the container is
utilized to actuate visual signalling means and only so much
thereof as is essential for that purpose is permitted to
escape from the container. When the signalling means has been
actuated to display a signal indicating a diminution of
pressure, further discharge of gaseous fluid from the container
is prevented, thereby retaining the gaseous fluid in the con-
tainer to the greatest extent possible under the circumstances.
Basically, the apparatus of the invention is preferably
used as a composite replacement for standard known tire valve
structures, functionally incorporating the operational
features thereof while additionally serving as a pressure loss

indicator for the tire.
The apparatus of this invention therefore consists of
a valve for normally confining a gaseous fluid in a container
comprising a tubular housing, a substantially annular valve
seat in the ~ousing coaxial therewith, a valve poppet in the
housing biased by the gaseous fluid in the container into
sealing engagement with the valve seat, piston plunger means
movably contained in said housing, an end of said plunger
extending through an open end of said housing remote from said
valve seat, seal means on said plunger end operatively coact-
ible with said housing proximate said open end, said valve

poppet and said seat constituting a first seal to prevent gas
escape from said container, said plunger end and seal means
constituting a secondary gas escape prevention means.

-- 1 --
$3~''

i J 7~22

THE PREFER~ED EMBODIMENT OF THE IN~ENTION
A presently preferred embodiment of the invention is
illustrated in the accompanying drawing in which:
Figure 1 is a side elevation of a typical vehicle
wheel on which is mounted a pneumatic tire having associated
therewith apparatus embodying the present invention;
Figure 2 is an enlarged axial sectional view, and
partly in elevation, of the invention illustrating the mecha-
nical elements thereof in relation to each other while fluid
pressure in the tire is at or above the desired pressure, but
below which the signalling means will be actuated to indicate
a lower than desired pressure in the tire;
Figure 3 is a corresponding view but showing the
changed relationship of the components which occur upon a
diminution of pressure in the tire below a desired value; and
Figure 4 is a corresponding view showing application
of a tire gauge, inflation hose fitting or the like utilized
for determining the pressure in the tire or reinflating it,
respectively.
More specifically, the invention includes a hollow,
substantially cylindrical housing generally designated 1, which
is shown as attached on a vehicle whee~ 2, on which is mounted
a pneumatic tire 3. The housing 1 is attached to the wheel 2
by insertion through a hole in the wheel rim, from which it
projects inwardly toward the wheel axis and communicates with
the interior of the tire. Appropriate means including a gasket
4, and nut 5, threaded on the housing 1, assure an air-tight
connection between the exterior of the housing 1 and the wheel
rim 2', about the hole through which the housing 1 projects, a
shoulder 6 on the housing 1 providing a seat for the gasket 4.

~ 1 7~9~2

Internally, the housing bore is divided into two
axially spaced chambers by a spacing washer 10 engaging and
operatively connected with an annular shoulder 11 in the bore.
Chamber 12, adjacent the wheel 2, contains pressure retaining
valve elements normally effective for maintaining the fluid
pressure in the tire, while a second chamber 13 contains
signalling means which are actuated when the pressure in the
tire declines below a predetermined value.
The chamber 12, considered progressively in the direc-
tion away from the inner end of the housing which projects into
and is in communication with the interior of the tire 3, has an
annular groove 14 in which is seated a resilient split retaining
ring 15 which serves as retaining means for a circular poppet
member 16, carrying an annular gasket 17 engageable with an
annular valve seat 18 formed within the housing, and normally
cooperative with the poppet member to prevent escape of air
from the tire. In a preferred embodiment, the upper surface of
the poppet means can be cup shaped as at 16' to more positively
retain gasket 17.
Interposed between the poppet 16 and the spacing
washer 10 there is a calibrating compression spring 19, or
other appropriate yielding means, bearing at one end upon the
washer, and biasing the poppet member toward the retaining ring
15. This spring has a strength selected in accordance with the
pressure it is desired to maintain in the tire, and functions
to unseat and displace the poppet member 16 and gasket 17 from
seat 18 when the pressure in the tire, in relation to external
ambient pressure, declines below a predetermined selected value.
The spring and poppet thus cons~itute components of a differ-
ential-pressure-responsive valve operating to function as
described.
-- 3 --

~ l7~g22

The second chamber 13 contains the signalling means and
actuating means therefor, being axially aligned in the housing
bore with the valve-containing chamber 12. Disposed within
chamber 13, and movable therein axially with relation to the
housing, and having an indicator head 20 normally projecting
slightly beyond the adjacent end of the housing, is a low tire
pressure signalling piston 21 preferably distinctively colored
for ready visual recognition when projected to its extreme posi-
tion (Figure 3). The piston carries, in appropriate annular
grooves, resilient, preferably elastomeric, upper and lower
O-rings 23, 24. The grooves are intermediate axially spaced
piston zones of progressively increasing diameter from head 20,
through an intermediate zone 25 to spindle 27, projecting
axially from the piston into chamber 12, as will hereinafter
more fully appear.
The interior wall of chamber 13 proximate its upper
end smoothly merges into a chamber 13' of lesser diameter. The
merging section is indicated at 29. The chamber 13' merges at
shoulder 30 into an upper chamber like outlet opening 31. The
interior walls of the chambers are finished smoothly to insure
a seal against intrusion of dust or other foreign matter at
points where engaged by O-rings 23, 24. The merging section at
30 provides an annular seat spaced axially inwardly from open-
ing 31, and when the piston is projected outwardly of the
housing, then O-ring 24 is brought into sealing engagement
therewith. The wall of the chamber 13' axially inwardly of
seat 30 engages O-ring 24 in such a sealing relation as to
inhibit free escape of air from the tire during the projection
of the piston caused by release of air from the tire into the
housing upon unseating of poppet member 16.
The piston is normally held in a non-projected position


1 ~ 70922


(Figure 2) by a return spring 28 interposed between it and
spacing washer 10. Chamber 13 is of somewhat enlarged diameter
inwardly from chamber 13', which is normally engaged by O-ring
24, to afford a path for air escape or inlet when the piston 20
is depressed from its normal position, such as by application
of a tire gauge G, or the like, (Figure 4) at the end of housing
1, or to introduce air into the tire in a known manner from a
source of presurized air.
As will be evident from the foregoing, the signalling
means in accordance with the invention, as embodied in means for
low pressure signalling in a pneumatic vehicle tire, can replace
known types of valve means, such as those normally provided to
enable the tire to be inflated, performs all the functions of
the latter, and additionally providing low tire pressure signal-
ling means.
Under normal conditions (Figure 2), assuming the tire
is properly inflated, the engagement of O-ring 23 with its seat
in opening 31 at the end of housing 1 excludes intrusion of
foreign matter into the housing, while the internal pressure in
the tire holds poppet member 16 and gasket 17 against valve
seat 18 to prevent escape of air from the tire.
However, on loss of pressure in the tire for any reason,
the pressure against poppet member 16 declines correspondingly
and when it has declined to a value less than that being
asserted against the poppet member 16 by compression spring 19,
the latter unseats the poppet member (Figure 3), allowing pres-
sure from within the tire to be exerted against the piston 26.
This air pressure, in addition to, or in combination with, force
of return spring 28, causes the piston to pop-up into the
position of Figure 3. Since the O-ring 24 engages the wall of

chamber 13' in sealing relation, inhibiting escape of air from


-- 5 --

~ 1 70~22


the interior of the housing, the pressure exerted against the
piston, in conjunction with force of spring 28, forces it to
move axially outward in chamber 13'. The piston is moved
axially outwardly until O-ring 24, carried by the piston,
engages seat 30 (Figure 3), preventing further escape of air
and, at the same time, exposing for ready observation the pre-
ferably distinctively colored zone 25 of the piston, thus con-
veying to an observer an indication that the tire is under-
inflated.
As noted, the piston carries a guide spindle 27 extend-
ing axially in the housing toward the poppet member 16, and it
is so positioned and of a length to engage the latter (Figure 4)
to facilitate normal servicing of the associated tire. Thus,
when, for example, it is desired to ascertain the pressure in
the tire, the usual valve depressing boss of a pressure gauge G
may be applied to the exposed piston head 20 to depress the
latter against the bias of return spring 28, and on engagement
of the free end of spindle 27 with poppet member 16, unseating
the latter and releasing air from the tire to activate the
pressure gauge G.
Similarly, any other appropriate tool may be applied to
the piston head to either release pressure from the tire to
deflate it, or ~o introduce air under predetermined pressure
into the tire to inflate the same as desired. It will be
evident the spindle 27 may be secured to either the poppet
member 16, or to the piston 26 although not to both.
In effect, what the present invention provides is very
significant, and a very substantial contribution to the art.
The apparatus provides a tire low pressure visual indicator,
which as a composite entity can replace a tire valve as

currently known and used. It is of a construction adaptable for


1 1 70~22


mounting to a wheel rim by clamping mechanisms, or by a snap-in
type resilient base as known in the art.
Fewer parts are required to provide both valving and
low pressure indication, than of the type where the indicator
is ]oined to a usually known valve body.
The structure provides improved servicing air flow due
to the arrangement and cooperation of the plural chambers, and
coaction with the O-rings on the piston~
The device has greatly improved safety in use. This
is due in large part to the use of two seals, a primary seal P,
inside the rim, constituted by intercoacting engagement of the
gasket 17 on the poppet means 16, with its seat 18 with normal
tire air pressure present, and a secondary or back-up seal, BU,
constituted by the warning pin mechanism through interengagement
between O-ring 24 and merging portion 30 of chamber 13' proxi-
mate opening 31. The merging portion 30 is a sealing seat for
O-ring 24 under low tire pressure conditions, when the signall-
ing means has moved into the extended condition.
The invention is readily adaptable to on-board indica-

tion systems as well as the in place visual form as described.Positive movement of the indicator head to the extended posi-
tion could readily be transmitted to a system of a known type
for triggering an on-board system.
The device is also susceptible of use in applications
other than as tire pressure indicators. It could be used in any
situation where a fluid medium valving is needed, and the
features as above delineated would be highly desireable.




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