U.S. patent application number 11/787924 was filed with the patent office on 2008-10-23 for multiple-function tire valve cap with low pressure safety indicator.
Invention is credited to Min Wu.
Application Number | 20080257027 11/787924 |
Document ID | / |
Family ID | 39855482 |
Filed Date | 2008-10-23 |
United States Patent
Application |
20080257027 |
Kind Code |
A1 |
Wu; Min |
October 23, 2008 |
Multiple-function tire valve cap with low pressure safety
indicator
Abstract
A multiple-function valve cap is disclosed for mounting on a
valve stem of a tire for indicating a safe pressure condition or a
low pressure warning. The multiple-function valve cap includes a
pressure indicator assembly having a piston including a safe
pressure indicator, and an internal bore. A warning indicator is
seated within the internal bore of the piston. A biasing spring is
fitted between the low pressure warning indicator and the safe
pressure indicator, and acts to urge them apart, such that the
warning indicator is displayed when low pressure is applied to the
piston. When a safe level of air pressure is applied to the piston,
the piston is moved against the force of the biasing spring to
surround the warning indicator, and the safe pressure indicator is
displayed.
Inventors: |
Wu; Min; (San Jose,
CA) |
Correspondence
Address: |
Patent Law Office of Larry Guernsey
P.O. Box 720247
San Jose
CA
95172-0247
US
|
Family ID: |
39855482 |
Appl. No.: |
11/787924 |
Filed: |
April 18, 2007 |
Current U.S.
Class: |
73/146.8 ;
340/626 |
Current CPC
Class: |
B60C 23/0496 20130101;
G01D 7/005 20130101 |
Class at
Publication: |
73/146.8 ;
340/626 |
International
Class: |
B60C 23/04 20060101
B60C023/04 |
Claims
1. A tire valve cap for mounting on a valve stem of a tire for
indicating a safe pressure condition or a low pressure warning,
comprising: a pressure indicator assembly including: a piston
having a safe pressure indicator, and an internal bore; a warning
indicator which is seated within said internal bore of said piston;
a biasing spring which is fitted between said warning indicator and
said safe pressure indicator, and acts to urge them apart, such
that said warning indicator is displayed when low pressure is
applied to said piston, and when a safe level of air pressure is
applied to said piston, said piston is moved against the force of
said biasing spring to surround said warning indicator, and said
safe pressure indicator is displayed: a main housing, having a
transparent portion through which said warning indicator and said
safe pressure indicator are displayed, wherein pressure to be
monitored is applied to a bottom plate of said piston, and a safe
level of air pressure will move said piston upward into said
transparent portion of said main housing against the urging of said
biasing spring: and an internal housing having an inner bore into
which said piston is seated: wherein said internal housing includes
an air nozzle having a contact plate which engages a valve core pin
of a tire valve stem to allow flow of pressurized air into and out
of the tire and said air nozzle includes an air passage which
conveys pressurized air to contact a bottom plate of said piston
which is seated in said inner bore of said internal housing,
wherein said contact plate includes a slot which forms a horizontal
air passage for air to flow between said tire valve stem and said
air passage of said air nozzle and wherein said inner bore of said
internal housing includes an enlarged diameter inner bore portion
wherein said piston fits within said internal housing inner bore,
and includes a lipped O-ring which forms an air tight seal with
said internal housing inner bore when sufficient pressure has
displaced said piston upwards a sufficient amount, but which does
not contact said inner bore of said internal housing when
insufficient pressure exists to displace said piston upwards, and
thus passage of air is allowed.
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. The tire valve cap of claim 1, wherein: said main housing
includes an air entry port through which air from an air source may
be pumped to enter said tire without removal of said cap gauge from
said valve stem.
11. The tire valve cap of claim 10, wherein: said warning indicator
includes a flange which is urged by said biasing spring to close
said entry port when air from an air hose is not being pumped into
said tire.
12. The tire valve cap of claim 11, wherein: said bottom plate of
said piston includes a slot which forms a horizontal air passage
for air to flow between said air entry port and said air passage of
said air nozzle of said internal housing.
13. The tire valve cap of claim 12, wherein: said pressure
indicator assembly is compressible against said biasing spring when
high pressure air is to be delivered to said tire.
14. The tire valve cap of claim 1, wherein: said safe pressure
indicator is a green colored sleeve which is a portion of said
piston.
15. The tire valve cap of claim 1, wherein: said warning indicator
is a red colored sleeve.
16. The tire valve cap of claim 1, wherein said main housing
further comprises: a locking nut having interior screw threads to
engage external threads of a tire valve stem.
17. The tire valve cap of claim 1, further comprising: a
calibration screw, which can be adjusted to calibrate the cap gauge
to the appropriate air pressure in a tire.
18. The tire valve cap of claim 17, wherein: said calibration screw
is threadably engaged in said warning indicator, and acts to
compress said biasing spring when rotated.
19. A tire valve cap for mounting on a valve stem of a tire while
in continued use on a vehicle for indicating when the tire pressure
of a vehicle tire is either low or sufficient, comprising: a
housing having an engagement means for the operative engagement of
said tire valve cap with said valve stem of said tire; a pressure
indicator assembly within said housing, said pressure indicator
assembly comprising; a low pressure warning indicator which
indicates a low pressure condition; a safe pressure indicator which
indicates a sufficient pressure condition; a biasing spring which
forces said safe pressure indicator out of view unless sufficient
pressure is applied on said bottom plate of said safe pressure
indicator to force it into view in place of said warning indicator,
wherein said warning indicator includes an inner colored sleeve,
and said safe pressure indicator includes an outer colored sleeve,
which is movable against the urging of said biasing spring to
surround said inner colored sleeve, wherein said outer colored
sleeve is colored green and said inner colored sleeve is colored
red, wherein said housing includes a locking nut portion having
internal threads which are configured to mate with external threads
of said valve stem, said housing includes an air entry port through
which air from an outside source may be pumped to enter said tire
without removal of said cap gauge from said valve stem, said inner
colored sleeve includes a flange which is urged by said biasing
spring to close said entry port when air is not being pumped into
said tire, and said housing includes a transparent portion through
which said warning indicator and said safe pressure indicator may
be viewed during the corresponding pressure conditions: and an
internal housing having an inner bore, an enlarged diameter inner
bore portion, an air nozzle and a contact plate, wherein said outer
colored sleeve fits within said internal housing inner bore, and
includes a lipped O-ring which forms an air tight seal with said
internal housing inner bore when sufficient pressure has displaced
said inner colored sleeve upwards a sufficient amount, but which
does not contact said inner bore of said internal housing when
insufficient pressure exists to displace said inner colored sleeve
upwards.
20. (canceled)
21. (canceled)
22. (canceled)
23. (canceled)
24. (canceled)
25. (canceled)
26. (canceled)
27. (canceled)
28. The tire valve cap of claim 19, further comprising: a secondary
spring positioned between said internal housing and said outer
colored sleeve.
29. The tire valve cap of claim 19, wherein: said calibration screw
is included in said warning indicator, and acts to compress said
biasing spring when rotated.
Description
[0001] This application makes reference to the Disclosure Document
filed Jan. 9, 2007 by the present inventor.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to pressure gauges
and more particularly to a low pressure safety indicator, which is
incorporated into a tire valve cap for a tire valve stem.
[0004] 2. Description of the Prior Art
[0005] As highways become ever more crowded, safety becomes ever
more important for the millions of people who use automobiles for
transportation. Improper tire pressure is a major cause of tire
malfunction and can also have a significant effect on gas mileage
achieved by the vehicle. A tire that is under-inflated causes more
drag, more friction and more heat, thus rolls less efficiently than
a tire with proper inflation. In extreme cases, under-inflation can
result in wear and over heat on improper portions of the tire and
can even contribute to blow-outs. Thus, it is very important that
drivers have an easy and convenient way to monitor the low pressure
in their vehicle's tires.
[0006] The conventional device for checking tire pressure is the
well-known "tire pressure gauge", which is applied to the valve
stem of each tire in turn. Internal pressure forces a tire pressure
gauge indicator to emerge from the gauge's casing, and the tire
pressure gauge indicator includes markings or digital numbers which
indicate the level of pressure in the tire. However, each valve
stem generally includes a valve cap, which keeps grit and road
grime from getting into the tire valve. In order to measure the
tire pressure, this valve cap must be removed, and placed in a safe
place, while the tire pressure gauge is pressed onto the valve
stem. There is usually some loss of pressure during this operation,
which can be unfortunate for some tires which have borderline low
pressure to begin with. Additionally, the application of the gauge
generally requires the user to kneel or stoop on the roadway near
the tire, which can be awkward and messy, and damaging to clothing.
At a minimum, the user's hands generally become soiled to some
degree, and the markings on the stick tire gauge can be difficult
to make out, especially in dim light. Consequently, many users find
it inconvenient to make proper pressure checks and the tire
pressure of many vehicles are under-inflated. Recent legislation in
the U.S. (namely the Transportation Recall Enhancement,
Accountability, and Documentation, or "TREAD" act), has mandated
the use of tire valve caps with low pressure warning indicators to
correct this problem.
[0007] Thus, there is a need for a tire valve cap which does not
require removal from a valve stem, is easy to use to check tire
pressure and does not require the user to get messy in order to
properly inflate a tire. The user is thus encouraged to monitor
pressure more closely and may travel more safely.
[0008] There have previous attempts to develop more convenient tire
pressure indicators which address some of these concerns. In
particular, U.S. Pat. No. 1,494,001 to McPherson discloses a
combined dust cap and tire gauge having numerical values which are
displayed by markings on the exterior of the cap in response to
internal tire pressure. This has the disadvantage of being
difficult to read from a distance or in dim light. U.S. Pat. No.
5,083,457 to Schultz discloses a remotely actuated tire pressure
sensor having a transducer mounted on a tire stem which sends
information to a hand-held remote display unit. This includes
electronics which may be fragile and costly to manufacture, and
requires the use of a remote display unit, which may become lost or
damaged. U.S. Pat. No. 6,525,655 to Huang discloses a
diaphragm-type tire pressure gauge which can include an internal
rod which is advanced by air pressure from a tire to display
various colors or marked with data units. An alternate of Huang
includes an LED which is activated by tire pressure. This however,
requires electronics including a power supply of some sort, and can
be expected to be costly and relatively difficult to
manufacture.
[0009] Thus, there is a need for a tire valve cap which uses a
simple mechanical mechanism without external power which is easy
and inexpensive to use, allows easy addition of air to the tire,
presents an easily readable low pressure safety indication and is
less susceptible to become unreadable or discolored than prior
devices.
SUMMARY OF THE INVENTION
[0010] A multiple-function valve cap is disclosed for mounting on a
valve stem of a tire for indicating either a safe pressure
condition or a low pressure warning, which allows easy addition of
air into tires. For purposes of this application, this tire
multiple-function valve cap will be referred to as a tire valve
cap. The tire valve cap includes a low pressure indicator assembly
having a piston including a safe pressure indicator, an internal
bore, and a bottom plate. A low pressure warning indicator is
seated within the internal bore of the piston. A biasing spring is
fitted between the low pressure warning indicator and the safe
pressure indicator, and acts to urge them apart, such that the low
pressure warning indicator is displayed when insufficient pressure
is applied to the piston. When a safe level of air pressure is
applied to the piston, the piston is moved against the force of the
biasing spring to surround the low pressure warning indicator, and
the safe pressure indicator is displayed.
[0011] It is an advantage of the present invention that it provides
an easy visual representation of the pressure in each of a user's
tires, which can be viewed without close inspection or the reading
of numbers on a gauge.
[0012] It is another advantage of the present invention that it
provides a visual display that can be easily viewed without
carrying or attaching additional equipment.
[0013] It is a further advantage of the present invention that it
provides a tire valve cap that remains in place on a tire even
while the tire is in operation.
[0014] It is yet another advantage of the present invention that it
provides a tire valve cap that is relatively inexpensive and easy
to manufacture.
[0015] It is an additional advantage of the present it provides a
tire valve cap that can be calibrated to adapt to many types and
models of tires having different pressure requirements.
[0016] It is an additional advantage of the present it provides a
tire valve cap that provides a visual display without using
external power.
[0017] It is a yet further advantage of the present that it allows
additional high pressure air to be added to a tire while the tire
valve cap is still mounted on the tire's valve stem.
[0018] It is another advantage of the present that it provides a
tire valve cap that is easy to monitor even in dim light and thus
encourages proper monitoring of pressure, and safe operation of the
vehicle on which it is used.
[0019] The foregoing and other objects, features and advantages of
the present invention will be apparent from the following detailed
description of the preferred embodiments, which make reference to
the several figures of the drawings.
IN THE DRAWINGS
[0020] FIG. 1 is an isometric view of a representative tire showing
the mounting position of the tire valve cap of the present
invention;
[0021] FIG. 2 is a side plan view of the tire valve cap of the
present invention;
[0022] FIG. 3 is an exploded side view of the tire valve cap of the
present invention;
[0023] FIG. 4 is a cutaway view of the tire valve cap of the
present invention when disengaged from mounting on a tire stem;
[0024] FIG. 5A is a cutaway view of the tire valve cap of the
present invention when engaged on a tire stem which contains
sufficient pressure;
[0025] FIG. 5B is an detail isometric view of the contact plate of
the internal housing;
[0026] FIG. 6A is a cutaway view of the tire valve cap of the
present invention when engaged on a tire stem as additional air
pressure is added to the tire;
[0027] FIG. 6B is a detail view of the portion of the tire valve
cap enclosed in the detail circle A of FIG. 6A; and
[0028] FIG. 6C is a detail perspective view of the bottom plate of
the inner colored sleeve.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] The present invention comprises a tire valve cap, which is
configured as a tire valve stem cap, as depicted in FIGS. 1-6C, all
of which will be referred to generally in the following
discussion.
[0030] A tire 1 of general type is shown in FIG. 1, having a valve
stem 2, having exterior threads 3. The present tire valve cap 10 is
shown mounted on the valve stem 2 by means of interior threads 12
(see FIG. 4) in the tire valve cap 10, in the usual manner in which
a cap is mounted on a valve stem of a tire.
[0031] As shown particularly in FIGS. 2-4, the tire valve cap 10
includes a housing 14, which has at least one transparent
cylindrical portion 16, preferably made of transparent plastic.
Within the housing 14, is a pressure indicator assembly 18, which
includes an inner colored sleeve 20, which is preferably red in
color, a biasing spring 22, and an outer colored sleeve 24, which
is preferably green in color. As will be discussed below, the outer
sleeve 24 is movable around the inner sleeve 20, and can act to
cover the inner sleeve 20 when sufficient air pressure acts to
force the outer colored sleeve 24 against the force of the biasing
spring 22. The housing 14 also includes a locking nut portion 26,
which contains the internal threads 12, and a calibration screw 28
having a screw slot 29, which will be discussed below.
[0032] The outer colored sleeve 24 is fitted with a lipped O-ring
30. An internal housing 32 fits within the housing 14, and
surrounds the outer colored sleeve 24. The lower portion of the
internal housing 32 shall be referred to as the air nozzle 36,
which surrounds an air passage 38. The tip of the air nozzle 36 has
a contact plate 40. A gasket seal 34 surrounds a portion of the air
nozzle 36 and makes an air-tight seal with the inner walls 42 of
the locking nut portion 26 (see especially FIG. 4). The inner bore
44 of the internal housing 32 is larger than the diameter of the
outer colored sleeve 24, and thus leaves an air passage 82 which is
connected to the air passage 38 in the air nozzle 36, as will be
discussed below. The outer colored sleeve 24 also includes a bottom
plate 46.
[0033] A secondary spring 23 is also preferably included which
seats in a cavity 39 in the internal housing 32. As will be
discussed below, this secondary spring 23 aids air pressure from
the tire to urge the outer colored sleeve 24 upwards against the
biasing spring 22.
[0034] FIG. 4 shows the tire valve cap 10 disengaged from any tire
valve stem 2. The biasing spring 22 is captured in the space
surrounded by the inner colored sleeve 20 and the outer colored
sleeve 24. The lower end 48 of the spring 22 contacts the upper
internal surface 50 of the outer colored sleeve 24, and the upper
end 52 of the spring 22 contacts the lower face 54 of the
calibration screw 28, included in the inner colored sleeve 20. When
the tire valve cap 10 is disengaged, the biasing spring 22 forces
the outer colored sleeve 24 downward so that the bottom plate 46
contacts the internal housing 32. The calibration screw 28 is
fitted in the screw threads 56 in the inner colored sleeve 20, so
as the biasing spring 22 forces the calibration screw 28 upward,
the inner colored sleeve 20 is urged upwards as well. The upward
movement of the inner colored sleeve 20 is stopped by flanges 58 on
the inner colored sleeve 20 which contact a lip 60 on the main
housing 14. The secondary spring 23 is also shown seated in the
cavity 39 in the internal housing 32.
[0035] There is an air vent 62 in the calibration screw 28. This
air vent 62 allows the air pressure within the inner colored sleeve
20 to remain at atmospheric pressure, and thus does not oppose the
upward movement of the outer colored sleeve 24. It will be seen
that the compression of the biasing spring 22 is adjustable by
advancing the calibration screw 28 in the threads 56 of the inner
colored sleeve 20, by use of a tool inserted into the screw slot
29. By this mechanism, the tire valve cap 10 can be calibrated, as
will be discussed below.
[0036] FIG. 5A shows the tire valve cap 10 mounted in place on a
tire valve stem 2 on a tire with a sufficient amount of air
pressure. The tire valve cap 10 has been screwed on so that the
internal threads 12 of the tire valve cap 10 have engaged the
external threads 3 of the valve stem 2. As the tire valve cap 10 is
screwed on, the valve core pin 66 of the valve stem 2 meets the
contact plate 40 of the air nozzle 36. As the tire valve cap 10
advances further in its threaded engagement with the valve system,
the valve core pin 66 is depressed by the contact plate 40, and air
is released from the tire 1 (see FIG. 1).
[0037] Referring now also to FIG. 5B, a perspective view is shown
of the contact plate 40 of the air nozzle 36 of the internal
housing 32. A slot or horizontal passage 84 is shown formed in the
contact plate 40. This allows air flow from the tire 1 to enter the
contact plate 40 through the horizontal passage 84 and pass into
and through the air passage 38 in the air nozzle 36 into the air
chamber 68. As this air is at greater pressure than that of the
atmosphere, it pushes against the bottom plate 46 of the outer
colored sleeve 24. Aided by the secondary spring 23, this forces
the entire outer colored sleeve 24 upwards, compressing the biasing
spring 22. The lipped O-ring 30 is seated in an O-ring groove 31
made in the outer colored sleeve 24, and it contacts the smooth
surface of the internal housing inner bore 44, creating an
air-tight seal. This leaves an air chamber 68, which becomes larger
in extent as the air pressure is higher. If the air pressure in
this air chamber 68 is sufficient, the green outer colored sleeve
24 is forced upward against the force of the biasing spring 22
until it surrounds the red inner colored sleeve 20. Thus, the user
can observe that the color viewed through the transparent portion
16 of the main housing changes from red to green, indicating a
sufficient amount of air pressure in the tire for safe operation.
As long as the air pressure in the tire remains sufficient, the
green inner colored sleeve 24 safety indicator will be visible
through the transparent portion 16. However, if the pressure falls
too low, then the biasing force of the spring 22 will overcome the
force of the air pressure in the air chamber 68, and the green
outer colored sleeve 24 safety indicator will be forced down out of
the transparent portion 16, and the red colored inner sleeve 20
will be displayed as a low pressure warning indication.
[0038] This tire valve cap 10 that provides a mechanism for warning
the user of the status of pressure in each of the tires 1 which is
convenient, easy to observe, even in dim light, and the colored
sleeves 20, 24 are located in close proximity to the transparent
housing 16, so they are more easily visible than indicators of the
prior art.
[0039] Another advantage of the tire valve cap 10 of the present
invention is that it is preferably configured so that high pressure
air may be introduced into the tires through an entry port 70 in
the top of the tire valve cap 10. Thus, if a status indicator of
low pressure is observed, the user may refill the pressure in the
tire without removing the cap gauge 10. FIG. 6A illustrates a cap
gauge 10 during such a refilling operation.
[0040] The entry port 70 is formed in the main housing 14, and is
bounded at its upper edge by the main housing lip 60, which
surrounds a smaller diameter aperture 72 for the upper portion of
the entry port 70. This aperture 72 is generally sealed against
dirt and water intrusion by engagement of the flanged portion 58 of
the inner colored sleeve 20 with the lip 60, as will be discussed
below.
[0041] Referring also to FIGS. 4 and 5A, when more pressure is not
being added to the tire, the inner colored sleeve 20 is urged
upward by the biasing spring 22, until the flange 58 contacts the
lip 60 of the main housing 14. During operation with sufficient
pressure included, as shown in FIG. 5A, the outer colored sleeve 24
is forced upward by air pressure, so the biasing spring 22 is
compressed, and the inner colored sleeve 20 is seated with the
flange 58 engaged with the lip 60.
[0042] Returning to FIG. 6A, when high pressure air is to be added
to a tire through the tire valve cap 10, an air hose or other high
pressure air source (not shown) having an air chuck pin 76 is
pressed onto the cap tire valve cap 10. The air chuck pin 76
presses on the top of the inner colored sleeve 20 containing the
calibration screw 28. The inner colored sleeve 20 is forced down
against the biasing spring 22, which moves the flange 58 of the
inner sleeve 20 out of its seat against the lip 60 of the main
housing 14, thus opening the entry port 70 to air flow from the air
hose. It can be seen that the air chuck pin 76 has forced the outer
colored sleeve 24 down until the bottom plate 46 meets the floor 78
of the internal housing 32.
[0043] FIG. 6C is an isometric view of the bottom plate 46 of the
outer colored sleeve 24. From this perspective, it can be seen that
the bottom plate 46 includes a slot which creates a horizontal
passage 86, much in the same way as a similar slot creates a
horizontal passage 84 in the contact plate 40 of the air nozzle 36,
as referred to above. The horizontal passage 86 in the bottom plate
46 allows air to pass to or from the upper end of the air passage
38 which has been configured in the air nozzle 36.
[0044] FIG. 6B shows an enlarged detail view of circle A of FIG.
6A. In this detail view, it can be seen that the inner bore 44 of
the internal housing 32 has an enlarged diameter portion 80. The
tip of the lipped O-ring 30 is formed with a diameter such that it
contacts the internal housing inner bore 44 when the outer colored
sleeve 24 is pressed upward by tire air pressure, as in FIG. 5A.
This makes an air-tight seal between the outer colored sleeve 24
and inner bore 44 of the internal housing 32. However, when the
outer colored sleeve 24 has been forced downward by an air chuck
pin 76, as in FIG. 6A, or when the tire pressure is low, or if the
tire valve cap 10 is disengaged, as in FIG. 4, the lipped O-ring 30
resides in the enlarged diameter portion 80 of the internal housing
inner bore 44. In this position, the lipped O-ring 30 does not
contact the walls of the internal housing 32, and no air-seal is
formed. High pressure air from an air hose is thus able to freely
flow through the upper air passages 82, into horizontal passage 86
of the bottom plate 46, through air passage 38 of air nozzle 36,
through the horizontal passage 84 of contact plate 40, around valve
core pin 66 finally into the valve stem 2, and thus into the tire
(not shown).
[0045] Thus, re-pressurizing of the tire can be accomplished
without removing the tire valve cap 10, which is a great
convenience. The user can introduce a bit of air pressure, remove
the air hose, and see if the pressure is sufficient to allow the
green outer colored sleeve 24 safety indicator to be displayed. If
not, more is added until a safe level of pressure has been achieved
and the green safety indicator is in view.
[0046] As mentioned above, the tire valve cap 10 can be calibrated
to allow for the varying pressure in many types and styles of
tires. This is accomplished by adjusting the calibration screw 28
using screw slot 29. The compression of the biasing spring 22 is
adjustable by advancing the calibration screw 28 in the threads 56
of the inner colored sleeve 20. As the calibration screw 28 is
advanced in the screw threads 56, the spring is compressed more,
and thus more force from air pressure is required to push the outer
colored sleeve 24 safety indicator upward into view. Alternately,
as the calibration screw 28 is backed out of the threads 56, the
spring tension is released, and less air pressure is required to
display the outer colored sleeve 24. By this mechanism, the air
pressure in the tire to be used can be adjusted for, so that the
green safety indicator is displayed at the appropriately calibrated
tire pressure.
[0047] Referring now to all the figures generally, the invention
can be described in alternate terms, namely the pressure indicator
assembly 18 can be described as including a piston 88, which has a
safe pressure indication 90, being the green outer colored sleeve
24, an internal bore 92 and a bottom plate 46. The pressure
indicator assembly 18 also includes a warning indicator 94, which
is the red inner colored sleeve 20, that is seated within the
internal bore 92 of the piston 88. Biasing spring 22 is fitted
between the warning indicator 94 and the safe pressure indicator
90, and acts to urge them apart. The warning indicator 94 is
visible through the transparent portion 16 of the main housing 14,
when low tire air pressure is applied to the piston 88. When a safe
level of air pressure is applied to the bottom plate 46 of the
piston 88, the piston 88 is moved upward against the force of the
biasing spring 22, so that the red warning indicator 94 is
surrounded within the internal bore 92 of the green safe pressure
indicator 90, and the green safe pressure indicator 90 is displayed
in the transparent portion 16.
[0048] When high pressure air is to be delivered to the tire 1, the
air chuck 76 forces the pressure indicator assembly 18 to compress
against the biasing spring 22 and opens entry port 70 so that air
can travel around the piston 88 and through the air passage 38 to
the tire 1.
[0049] While the invention has been disclosed and described with
regard to specific preferred embodiments, it is intended by the
inventor that the following claims cover not only the specific
embodiments described herein but other and further altered devices
that would occur to those skilled in the art upon reviewing the
specification and drawings provided herein. It is therefore
intended that the following claims cover all such alterations and
modifications which nevertheless include the true spirit and scope
of the invention.
TABLE-US-00001 1 tire 2 valve stem 3 external threads 10 tire valve
cap 12 interior threads 14 main housing 16 transparent portion 18
pressure indicator assembly 20 inner colored sleeve 22 biasing
spring 23 secondary spring 24 outer colored sleeve 26 locking nut
28 calibration screw 29 screw slot 30 lipped O-ring 31 groove in
outer colored sleeve 32 internal housing 34 gasket seal 36 air
nozzle 38 air passage 39 cavity 40 contact plate 42 locking nut
inner walls 44 internal housing inner bore 46 bottom plate 48
spring lower end 50 upper internal surface 52 spring upper end 54
calibration screw lower face 56 screw threads 58 flange, inner
sleeve 60 lip, main housing 62 air vent 64 vent pin 66 valve core
pin 68 air chamber 70 entry port 72 restricted aperture 74 upper
portion outer sleeve 76 air chuck 78 floor of internal housing 80
enlarged diameter portion 82 upper passage 84 slot, horizontal
passage, contact plate 86 slot, horizontal passage, bottom plate 88
piston 90 safe pressure indicator 92 internal bore 94 warning
indicator
* * * * *