Title: Low or no pressure usage indicator for a tire
Abstract: A low or no pressure use indicator for use on a tire is provided. The tire has a crown and a pair of sidewalls that extend from the crown. Each of the sidewalls has a bead located on an end of the sidewall that is opposite from the crown. The low or no pressure use indicator is located on a wall of one of the sidewalls. The low or no pressure use indicator is configured for indicating by a permanent physical change whether the tire has been subjected to an operation condition of an undesirable amount of low tire pressure.
Patent Number: 6,994,133 Issued on 02/07/2006 to Willard, Jr., et al.
| Inventors:
|
Willard, Jr.; Walter Lee (Greenville, SC);
Johnson; Kenneth (Taylors, SC);
Bryant; Richard (Spartanburg, SC)
|
| Assignee:
|
Michelin Recherche et Technique S.A. (CH)
|
| Appl. No.:
|
262260 |
| Filed:
|
October 1, 2002 |
| Current U.S. Class: |
152/152; 152/154.2; 73/146; 73/146.2 |
| Current Intern'l Class: |
B60C 23/00 (20060101); B60C 23/06 (20060101); B60C 11/24 (20060101) |
| Field of Search: |
73/146,146.2
152/154.2,516
|
References Cited [Referenced By]
U.S. Patent Documents
| 4074742 | Feb., 1978 | Chamblin.
| |
| 4134357 | Jan., 1979 | Chesley.
| |
| 4226274 | Oct., 1980 | Awaya et al.
| |
| 5171394 | Dec., 1992 | Laurent.
| |
| 5427166 | Jun., 1995 | Willard, Jr.
| |
| 5634993 | Jun., 1997 | Drieux et al.
| |
| 5700339 | Dec., 1997 | Billieres.
| |
| 5868190 | Feb., 1999 | Willard, Jr. et al.
| |
| 5891279 | Apr., 1999 | Lacour.
| |
| 5962778 | Oct., 1999 | Billieres.
| |
| 6494543 | Dec., 2002 | Hashimura et al.
| |
| 6536368 | Mar., 2003 | Hendrie.
| |
| 6769294 | Aug., 2004 | Yurjevich et al.
| |
| Foreign Patent Documents |
| 0557091 | Aug., 1993 | EP.
| |
Primary Examiner: Copenheaver; Blaine
Assistant Examiner: Fischer; Justin
Attorney, Agent or Firm: Dority & Manning, P.A.
Claims
We claim:
1. A tire for use on a vehicle, comprising:
a tire having a crown and a pair of sidewalls extending from said crown, each
of said sidewalls having a bead located on an end of each said sidewall opposite
from said crown; and
a low or no pressure use indicator located on at least one of said sidewalls
and integrally formed with the surface of said sidewall onto which said low or
not pressure use indicator is located, said low or no pressure use indicator configured
for indicating by a permanent physical change whether said tire has been subjected
to an operation condition of an undesirable amount of low tire pressure,
wherein the permanent physical change is fracturing.
2. The tire of claim 1, wherein said low or no pressure use indicator indicates
the condition of an undesirable amount of low tire pressure by a worn area on said
low or no pressure use indicator.
3. The tire of claim 1, wherein said low or no pressure use indicator is at least
one raised ring on the inner surface of one of said sidewalls.
4. A tire for use on a vehicle, comprising:
a tire having a crown and a pair of sidewalls extending from said crown, each
of said sidewalls having a bead located on an end of each said sidewall opposite
from said crown; and
a low or no pressure use indicator located on at least one of said sidewalls,
said low or no pressure use indicator configured for indicating by a permanent
physical change whether said tire has been subjected to an operation condition
of an undesirable amount of low tire pressure; and
wherein said low or no pressure use indicator is at least a pair of raised rings
on the inner surface of one of said sidewalls, one of said raised rings being inside
the other of said raised rings.
5. The tire of claim 1, wherein said low or no pressure use indicator is three
concentric raised rings on the inner surface of one of said sidewalls.
6. The tire of claim 1, wherein said low or no pressure use indicator is at least
one raised line on the inside surface of one of said sidewalls.
7. The tire of claim 6, wherein said low or no pressure use indicator is three
raised lines being substantially perpendicular to one another.
8. The tire of claim 1, wherein said low or no pressure use indicator is at least
one raised triangle on the inner surface of one of said sidewalls.
9. The tire of claim 8, wherein said low or no pressure use indicator is three
raised triangles all being of different size, the centers of all of said three
triangles being located at a common point.
10. The tire of claim 1, wherein said low or no pressure use indicator is at
least two intersecting raised lines on the inner surface of one of said sidewalls.
11. The tire of claim 10, wherein said low or no pressure use indicator is a
series of three substantially parallel raised lines that intersect another series
of three substantially parallel raised lines.
12. The tire of claim 1, wherein said low or no pressure use indicator has a
V-shaped cross section.
13. The tire of claim 1, wherein said low or no pressure use indicator has a
cross section that is substantially V-shaped having a circular member located at
an apex.
14. The tire of claim 1, wherein said low or no pressure use indicator is located
on an inner wall of one of said sidewalls at the equator of said tire.
15. The tire of claim 1, wherein at least a portion of said low or no pressure
use indicator is located on the inner surface of one of said sidewalls at a point
of between about 30° and about 80° from the circumferential direction
of said tire.
16. The tire of claim 1, wherein said low or no pressure use indicator indicates
a condition of an undesirable amount of low tire pressure by the presence of a
colored surface.
17. The tire of claim 1, wherein said low or no pressure use indicator is a raised
member that permanently physically changes when subjected to an operation condition
of an undesirable amount of low tire pressure.
18. The tire apparatus of claim 1, wherein said tire is a vertically anchored tire.
19. A tire for use on a vehicle, comprising:
a tire having a crown and a pair of sidewalls extending from said crown, each
of said sidewalls having a bead located on an end of said sidewall opposite from
said crown; and
a low or no pressure use indicator located on an inner wall of one of said sidewalls
and integrally formed with the surface of said inner wall onto which said low or
no pressure use indicator is located, said low or no pressure use indicator configured
for indicating whether said tire has been subjected to an operation condition of
an undesirable amount of significantly low tire pressure, said low or no pressure
use indicator indicating the condition of an undesirable amount of significantly
low tire pressure by an area subject to wear during significantly low pressure
use, said low or no pressure use indicator being a raised ridge pattern on the
inner surface of one of said sidewalls, wherein the cross-sectional shape of said
raised ridge pattern is configured so as to amplify stress such that a portion
of said raised ridge pattern is fractured due to the amplified stress to indicate
the condition of an undesirable amount of significantly low tire pressure, wherein
said worn area being a series of linearly aligned notches in said low or no pressure
use indicator along a line of maximum stress in said tire during the condition
of an undesirable amount of significantly low tire pressure.
Description
TECHNICAL FIELD
The present invention relates generally to tires and tire assemblies for pneumatic
tubeless tires. More particularly, the present invention relates to a low or no
pressure use indicator provided on a tire for indicating whether the tire has been
subjected to undesirable operation at low or no tire pressure.
BACKGROUND
During the twentieth century, tire designers and manufacturers have conceived
of various designs with which to enable a pneumatic tubeless tire to continue to
function even after a loss of air pressure. Generally, a tubeless tire is made
of a tread section with two sidewalls. Beads are located at the end of each sidewall
and are typically rigid. The beads fit onto a rim. Putting air pressure into the
interior of the tire causes the beads to seat against the rim and securely hold
the tire onto the rim.
The design and use of a run-flat tire is desirable for several reasons. First,
sudden loss of air pressure in a tire can result in a shifting of the position
of the tire, and subsequently a change in the internal tensioning forces originally
imparted by the tire on the rim to hold the tire thereon. The tire may become disengaged
from the rim under certain circumstances.
Second, a loss of air pressure forces the tread of the tire onto the rim.
The rim must then assume the loading from the weight of the vehicle and the dynamic
forces of the ride. As the rim is not designed for this purpose, damage to either
the rim, wheel, axle, or suspension can result. This in turn can lead to costly
repairs in addition to leaving the driver and passenger stranded once the rim is
too severely damaged to continue riding.
One such design of a run-flat tire is disclosed in U.S. Pat. No. 5,427,166 to
Willard, Jr., which is owned by the assignee of the present invention and is incorporated
by reference herein in its entirety for all purposes. This tire has thickened sidewalls
which are designed to bear the load of the vehicle in the event of loss of tire
inflation pressure.
Another run-flat type tire is the vertically anchored tire disclosed in U.S.
Pat. No. 5,891,279 which uses a flexible insert mounted on the wheel rim to support
the vehicle load if the tire loses inflation pressure.
Run-flat tires are desirable over conventional tires because with reasonable
and appropriate action by the driver, such tires can allow limited, continued mobility
for travel to a location where the tire can be inspected, repaired, or replaced
as necessary.
It is sometimes the case that run-flat tires, and also conventional tubeless
tires,
are driven in a condition where they are subjected to lower than normal operating
pressure. In such instances, pressure loss will only be severe enough to cause
the sidewall of the tire to flex. Flexing in these circumstances will impart stress
on the sidewall of the tire and possibly other areas as well. Although designed
to accommodate some degree of flexing, sustained flexing or severe flexing of a
tire may lead to the tire being damaged and unsuitable for further use.
Therefore, it is desirable to have an indication whether a tire has been
too severely damaged after experiencing a condition of lower than normal operating
pressure. If the tire has been subjected to an acceptable amount of stress, a technician
or motorist may repair the tire for continued use. If the tire was too severely
damaged, the technician or motorist may discard the damaged tire and install a
new one.
Typically, if a conventional tire has been subjected to a condition of
low tire pressure, "wrinkles" will develop on the inside and/or outside of the
sidewalls of the tire. The wrinkles are cracks and/or marks due to stress brought
about from an unacceptable degree of flexing of the tire. Run-flat tires may also
exhibit wrinkles if operated in a condition or undesirable low tire pressure. Tires
are typically deemed unfit for further use once the presence of wrinkles is noticed.
However, the tire may still be unsafe and/or unfit for further use even when wrinkles
are not present. Additionally, wrinkles may sometimes be hard to spot or subject
to subjective interpretation by a technician or motorist.
The present invention provides for a low or no pressure use indicator that is
located on a tire, either a conventional tire or a run-flat tire, in order to inform
a technician or motorist whether the tire has been subjected to an undesirable
condition of low pressure.
SUMMARY
Various features and advantages of the invention will be set forth in part
in the following description, or may be obvious from the description, or may be
learned from practice of the invention.
The present invention provides for a tire for use on a vehicle. The tire has
a crown and a pair of sidewalls that extend from the crown. Each of the sidewalls
has a bead located on an end of the sidewall that is opposite from the crown. A
low or no pressure use indicator is located on a wall of one of the sidewalls.
The low or no pressure use indicator is configured for indicating by a permanent
physical change whether the tire has been subjected to an operation condition of
an undesirable amount of low tire pressure.
Additionally, the present invention includes an exemplary embodiment
as described above where the low or no pressure use indicator indicates the condition
of an undesirable amount of low tire pressure by a worn or deteriorated area on
the low or no pressure use indicator.
According to one embodiment of the invention, the low pressure usage indicator
comprises at least one raised feature formed on a sidewall where the sidewall experiences
flexing during low pressure operation.
An alternative exemplary embodiment includes an exemplary embodiment as discussed
above where the low or no pressure use indicator is at least one raised ridge,
which may be in the form of a geometric figure, such as a ring, on the inner, surface
of one of the sidewalls. Alternatively, an exemplary embodiment exists where the
low or no pressure use indicator is three concentric raised rings on the inner
surface of one of the sidewalls.
A further exemplary embodiment of the present invention exists in an exemplary
embodiment as discussed above where the low pressure use indicator is at least
one raised triangle on the inner surface of one of the sidewalls. Further, another
exemplary embodiment exists where the low or no pressure use indicator is three
raised triangles all being of different size. The centers of all of the three triangles
are located at a common point.
An additional exemplary embodiment exists of a tire and/or a tire assembly as
discussed above where the low or no pressure use indicator has a V-shaped cross section.
Also, the low or no pressure use indicator may be in some embodiments, a member
that permanently physically changes when subjected to an operation condition of
an undesirable amount of low tire pressure, for example, by changing color with
increasing temperature, strain, or frequency of flexing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded assembly view of an exemplary embodiment of a tire assembly
of the present invention.
FIG. 2 is a perspective view of the tire assembly shown in FIG. 1.
FIG. 3 is a partial cross sectional view of an exemplary embodiment of a tire
assembly in accordance with the present invention. The view shows a low or no pressure
use indicator being located on an inner sidewall of the tire, the tire having normal
operational tire pressure.
FIG. 4 is a partial cross sectional view along the same lines as the exemplary
embodiment shown in FIG. 3, only having the tire being subjected to a low tire
pressure condition. The tire and the low or no pressure use indicator are shown
flexing in FIG. 4.
FIG. 5 is a cross section view taken along line 5—5 of FIG.
3 of an exemplary embodiment of a tire having a low or no pressure use indicator
located thereon.
FIG. 6 is a partial perspective view of a tire in accordance with an exemplary
embodiment of the present invention. The view shows the low or no pressure use
indicator having a series of worn areas.
FIG. 7A is a schematic view of an exemplary embodiment of a low or no pressure
use indicator in accordance with the present invention. The low or no pressure
use indicator is a series of coaxial rings.
FIG. 7B is a schematic view of an exemplary embodiment of a low or no pressure
use indicator in accordance with the present invention. The low or no pressure
use indicator is three substantially parallel straight lines.
FIG. 7C is a schematic view of an exemplary embodiment of a low or no pressure
use indicator in accordance with the present invention. The low or no pressure
use indicator is a series of three triangles each sharing a common center.
FIG. 7D is a schematic view of an exemplary embodiment of a low or no pressure
use indicator in accordance with the present invention. The low or no pressure
use indicator is a series of three substantially parallel lines that intersect
another set of three substantially parallel lines.
FIG. 8A is a detailed cross sectional view of a low or no pressure use indicator
in accordance with an exemplary embodiment of the present invention. The low or
no pressure use indicator has a V-shaped cross section.
FIG. 8B is a detailed cross sectional view of a low or no pressure use indicator
in accordance with an exemplary embodiment of the present invention. The low or
no pressure use indicator has a substantially V-shaped cross section that has a
circular member at an apex.
DETAILED DESCRIPTION
Reference will now be made in detail to embodiments of the invention, one
or more examples of which are illustrated in the drawings. Each example is provided
by way of explanation of the invention, and not meant as a limitation of the invention.
For example, features illustrated or described as part of one embodiment can be
used with another embodiment to yield still a third embodiment. It is intended
that the present invention include these and other modifications and variations.
Referring now to the drawings, a tire assembly
10 in accordance
with an exemplary embodiment of the present invention is shown in FIG. 1. The tire
assembly
10 is shown as being made of two basic components. An alloy or
steel integral wheel rim
12 is provided, and a rubber tire
16 is
placed onto the wheel rim
12. The tire assembly
10 is shown in an
assembled state in FIG. 2. The tire
16 may be vertically anchored to the
wheel rim
12 as described in U.S. Pat. No. 5,634,993 that is assigned to
the assignee of the present invention and incorporated herein for all purposes
in its entirety.
Although not shown in the exemplary embodiment shown in FIG. 1, a support
member (not shown) may be present on the wheel rim
12 in order to help carry
the static and dynamic loading when the tire
16 loses air pressure. For
instance, the support member may be configured as that shown in U.S. Pat. No. 5,891,279
that is assigned to the assignee of the present invention and incorporated herein
for all purposes in its entirety. Of course, other exemplary embodiments of the
present invention do not use a support member.
The tire
16 used in the present invention may be of any type, from a conventional
tire to a run-flat tire. One such run-flat tire assembly is disclosed in U.S. Pat.
No. 5,868,190 that is assigned to the assignee of the present invention and is
incorporated herein in its entirety for all purposes. The run-flat tire disclosed
in the '190 patent makes use of specially reinforced sidewalls to help prevent
the tire
16 from collapsing after the loss of air pressure. Another example
of a run-flat tire that may be used in conjunction with the present invention is
disclosed in U.S. Pat. No. 5,427,166 that is assigned to the assignee of the present
invention and is incorporated herein in its entirety for all purposes. This particular
tire has thickened sidewalls that support loading if air pressure is lost.
During a condition of low or zero tire pressure, the tire
16 will deflect
towards the wheel rim
12. This deflection in turn causes higher stress and
strains than deflection associated with normal tire operation. The stresses and
strains imparted on the tire
16 during a low or zero pressure incident may
be so severe as to render the tire
16 unusable. Evidence of stress or strain
in a tire
16 may be present due to the formation of "wrinkles" (not shown)
on the surface of the tire
16. Typically, these "wrinkles" are circumferentially
oriented around the tire
16 and an axis
28 about which the tire
16
rotates. The "wrinkles" are cracks and/or stress marks in the surface of the tire
16. Standard industry repair guidelines call for a technician or motorist
to check the tire
16 for the presence of "wrinkles" before repairing a hole
or other defect in the tire
16. The presence of "wrinkles" typically eliminates
the possibility of repairing and reusing the tire
16.
Zero pressure may be defined as atmospheric or ambient pressure. Low pressure
is pressure that is insufficient to support the design load of the tire
16.
In some instances, the standard recommended pressure range for a passenger vehicle
is from about 26 psi to about 30 psi. As used herein, low pressure is defined as
pressure below the design operating pressure of the tire
16 where damage
may occur during operation. In some instances, the pressure may be 10 psi or less.
Alternatively, in other exemplary embodiments of the present invention, the tire
16 may be designed so that damage occurs during use at any particular low
pressure or low pressure range.
The present invention provides for a low or no pressure use indicator
62
seen in one exemplary embodiment in FIG. 1, for allowing a technician or motorist
to inspect the tire
16 after a condition of low or zero pressure in order
to help determine the severity and/or duration of the low or zero pressure incident.
As shown in FIG. 1, the low or no pressure use indicator
62 is shown being
on the interior of the tire
16. The low or no pressure use indicator
62
may be located at other positions on the tire
16 in other exemplary embodiments
of the present invention. The low or no pressure use indicator
62 may be
a raised feature on the surface of the tire
16. In one exemplary embodiment,
the low or no pressure use indicator
62 is an arrangement of raised ridge-like
elements oriented to cross the area of maximum stress in a sidewall
20 of
the tire
16.
FIG. 3 shows a partial cross section view of a tire assembly
10 in accordance
with one exemplary embodiment of the present invention. Here, the sidewalls
20,
along with a first and second bead
22 and
24 in addition to a crown
88 of the tire
16 are constructed in accordance with the design disclosed
in the previously mentioned U.S. Pat. No. 5,427,166. The sidewalls disclosed in
the '166 patent have several layers of rubber to help keep the tire from collapsing
upon the loss of air pressure. A detailed explanation of the cross-sectional features
of the tire
16 is not necessary for one to gain an appreciation of the teachings
of the present invention. The present invention may be used with any cross-sectional
configuration of the sidewalls
20, beads
22 and
24, and the
crown
88, and the present invention is not limited to the particular configuration shown.
The tire
16 is provided with tire tread
18 on the outer surface.
The tire tread
18 is formed on the crown
88 of the tire
16.
The tire tread
18 used in the present invention may be of any variety, and
is not limited to a particular type. The two sidewalls
20 extend from the
crown
88 of the tire
16. As shown in this exemplary embodiment, the
sidewalls
20 are substantially vertical in orientation once seated onto
the wheel rim
12. The first bead
22 is present at the end of one
of the sidewalls
20, and the second bead
24 is present at the other
end of the other sidewall
20. The use of beads
22 and
24 help
keep the tire
16 attached to the wheel having a rim
12 and also help
to create an air seal to maintain tire pressure.
The wheel rim
12 has a first bead seat
36 and a second bead seat
38 formed therein for seating the first and second beads
22 and
24
respectively. The first bead seat
36 may be formed by a pair of humps
40
and
42. The second bead seat
38 may be formed by a pair of humps
44 and
46. It is to be understood, however, that the first bead seat
36 and the second bead seat
38 do not require the humps
40,
42,
44, and/or
46 to be present in other exemplary embodiments
of the present invention.
As shown in FIG. 3, the tire assembly
10 has a cavity
60 present
within the tire
16. The cavity
60 is formed by having the tire
16
being at a normal operating pressure. FIG. 4 shows the tire assembly
10
of FIG. 3 when the operating pressure becomes low or zero. This causes the cavity
60 to be reduced as the crown
88 and other portions of the tire
16
collapse towards the rim
12. The sidewalls
20 flex along with the
low pressure indicator
62.
The low or no pressure use indicator
62 is shown in FIG. 3 as being located
on the inner surface of one of the sidewalls
20. The low or no pressure
use indicator
62 is shown as being formed on the inner surface of this sidewall
20, but it is to be understood that the low or no pressure use indicator
62 may be either integrally molded with the sidewall
20 and tire
16, or as a separate piece attached later thereon. As can be seen in FIG.
4, the low or no pressure use indicator
62 deflects along with the sidewall
20 due to the attachment of the low or no pressure use indicator
62
to the sidewall
20.
In a condition of low or zero pressure, the sidewalls
20 of the tire
16
"bulge". The point of the largest deflection of the tire
16 in the direction
of the axis
28 during a condition of low or zero pressure occurs in a location
sometimes referred to in the art as an equator
94 of the tire
16.
In one exemplary embodiment of the present invention, the low or no pressure use
indicator
62 is located on the interior of the sidewall
20 at the
equator
94 of the tire
16. It is sometimes the case that due to the
maximum deflection of the tire
16 occurring at the equator
94 during
periods of low pressure, the maximum stress or strains imparted onto the tire
16
will also occur at the equator
94. It may be desirable to detect the point
of greatest stress in the tire
16. Another advantage of placing the low
or no pressure use indicator
62 at the equator
94 is for the ease
of convenience of the maintenance technician or motorist.
Additionally, it is also envisioned in the present invention to place
multiple low or no pressure use indicator s
62 on other portions of the
tire
16. For instance, several low or no pressure use indicator s
62
can be placed inside of the tire
16 both on the inner sidewall
20
and/or the inner crown
18 along with placing other low or no pressure use
indicator s
62 on the outside of the sidewall
20. The present invention
is not limited to a specific location of the low or no pressure use indicator
62.
An exemplary embodiment of the low or no pressure use indicator
62 is
shown
in greater detail in FIG. 5. Here, the low or no pressure use indicator
62
is comprised of three concentric rings each having a different diameter. An inner
ring
64 is present which is surrounded by a middle ring
66. An outer
ring
68 surrounds both the middle ring
66 and the inner ring
64.
These three rings
64,
66, and
68 are located on the inner
surface of one of the sidewalls
20.
FIG. 6 shows a partial perspective view of a partial portion of the tire
16
having a low or no pressure use indicator
62 being similar to that shown
in FIG. 5. Again, the low or no pressure use indicator
62 is a series of
rings
64,
66, and
68 that are located concentrically about
one another. However, the tire
16 shown in FIG. 6 is one that has been subjected
to a condition of low or zero pressure. The low or no pressure use indicator
62
indicates that the tire
16 has been subjected to such a condition by a series
of worn areas
70,
72, and
74 located on the rings
68,
66, and
64 respectively. The cracking of the raised rings
68,
66, and
64 provide a visual indication to the technician or motorist
that the tire
16 has been subjected to a condition of low or zero pressure.
The raised rings
68,
66, and
64 amplify the peak stresses
and strains that are present within the interior surface of the sidewall
20
during a condition of low or zero pressure. After a specific period of low or zero
pressure, the worn areas or notches
70,
72, and
74 begin to
occur. This deterioration provides an easily detectable visual indicator to be
used by a technician or motorist after the zero or low pressure condition in order
to determine whether the tire
16 is fit for reuse. Such visual indication
is advantageous over having the technician or motorist inspect the tire
16
for "wrinkles" or other signs of deterioration that may be more subjective and/or
harder to locate. The worn areas
70,
72 and
74 may also be
described as deteriorated in other exemplary embodiments of the invention, and
it is to be understood that the word "worn" is broad enough to cover areas that
are deteriorated.
A period of low or zero pressure causes an increased flex in the tire
16.
The flexing of tire
16 brings about stresses which cause a permanent physical
change in the low or no pressure use indicator
62. Ridges present in the
low or no pressure use indicator
62 will develop gaps and/or grooves once
subjected to a certain amount of stress.
Typically, the maximum stress or strain imparted on the tire
16
will be a circumferential line along the sidewall
20 of the tire
16.
As can be seen in FIG. 6, this maximum stress or strain line causes the worn areas
70,
72, and
74 to be in a substantially straight line with
respect to the circumferential direction of the tire
16. However, it may
be the case that the locations of the maximum stress or strain occur in other directions
in other tires
16. Therefore, the low or no pressure use indicator
62
has been advantageously designed in this exemplary embodiment of the present invention
to be a series of rings
68,
66, and
64 that in effect allow
for the intersection of the maximum stress or strain line in any direction.
Flexing of the tire
16 may create a stress concentration which will
contact the low or no pressure use indicator
62 and break the low or no
pressure use indicator
62 to form a worn area
70. The worn area
70
may indicate how hard and long the tire
16 has been driven after being subjected
to a condition of low or zero pressure. The amount of distance driven by the vehicle
during a period of low or zero tire pressure, which causes an amount of stress
in the tire
16, may cause the worn area
70. The beginning of deterioration
on the low or no pressure use indicator
62 along with the degree of the
deterioration may depend on both the severity of the low or zero pressure incident
as well as the geometry of the low or no pressure use indicator. For instance,
the thickness and cross sectional shape of the rings
68,
66, and
64 may be selected to allow for the worn areas
70,
72, and
74 respectively to be formed once subjected to different conditions of low
or zero pressure. The low or no pressure use indicator
62 may therefore
be designed in one exemplary embodiment of the present invention to have the worn
area
70 present if a moderate amount of low or zero pressure were imparted
onto the tire
16. However, such an amount of low or zero pressure may not
be enough to cause the tire
16 to be discarded. Additionally, the rings
66 and
64 may be constructed of such a geometry, size, and shape
so that once the presence of the worn areas
72 and
74 are seen, the
technician or motorist must replace the tire
16 due to the fact that an
unacceptable amount of stress or strain had been imparted onto the tire
16.
Various configurations of the low or no pressure use indicator
62
are presented in accordance with the present invention such that the worn areas
70,
72, and
74 may be formed in response to various driving
conditions. In one exemplary embodiment of the present invention, a run-flat tire
16 may have zero PSI present and be driven for a distance of between 50
to 100 kilometers in order for the start of deterioration of the low or no pressure
use indicator
62 to begin. In such a case, under inflation "wrinkles" may
also be present allowing for the low or no pressure use indicator
62 to
be an auxiliary indicator of the condition of low pressure. As such, in other exemplary
embodiments of the present invention, the low or no pressure use indicator
62
provides for a second way of determining whether the tire
16 has been subjected
to a condition of low or zero pressure. The low or no pressure use indicator
62
may be a redundant system in other exemplary embodiments of the present invention.
The low or no pressure use indicator
62 may be used on a regular or conventional
tire in order to highlight the "wrinkles" in another exemplary embodiment of the
present invention.
Although as shown as being three concentric rings
68,
66,
and
64 in FIG. 7A, it is to be understood that the low or no pressure use
indicator
62 may be of other configurations. For instance, the low or no
pressure use indicator
62 may be formed in another exemplary embodiment
by being a single ring as opposed to three rings. Additionally, any number of rings
may be used in other exemplary embodiments. Additionally, the low or no pressure
use indicator
62 does not need to be a ring, but may be in other exemplary
embodiments a straight line. FIG. 7B shows another exemplary embodiment of the
low or no pressure use indicator
62 where the low or no pressure use indicator
62 is formed by three substantially parallel lines
76. Again, any
number of lines
76 may be used in other exemplary embodiments of the present invention.
FIG. 7C shows another exemplary embodiment of the low or no pressure use indicator
62 that includes a series of three triangles. An inner triangle
82
is present with a middle triangle
80 surrounding the inner triangle
82.
An outer triangle
78 surrounds both the middle triangle
80 and the
inner triangle
82. All three of the triangles
78,
80, and
82 share a common center point. However, it is to be understood that in
other exemplary embodiments of the present invention, that the low or no pressure
use indicator
62 may be comprised of any number of triangles
78,
80, and
82. For instance, a single triangle may be used in one exemplary
embodiment while two triangles are used in another exemplary embodiment. The provision
of triangles
78,
80, and
82 is similar to the provision of
rings
68,
66, and
64 as shown in FIG. 7A in that a line of
maximum stress or strain will contact at least a portion of one of the triangles
78,
80, and
82.
FIG. 7D shows yet another exemplary embodiment of the low or no pressure use
indicator
62 in accordance with the present invention. Here, a series of
three substantially parallel angled straight lines
84 intersect another
series of angled substantially parallel straight lines
86. Again, a line
of maximum stress or strain will contact one of these lines
84 and/or
86
to provide for the visual indication of a low or zero pressure instant.
Although several designs of the low or no pressure use indicator
62
are shown in FIGS. 7A-7D, the present invention includes other exemplary embodiments
of the low or no pressure use indicator
62 that include other designs. For
instance, the low or no pressure use indicator
62 may be in the form of
a company logo or trademark. In fact, any conceivable design of the low or no pressure
use indicator
62 is possible in accordance with the present invention. Additionally,
the low or no pressure use indicator
62 may be a mark that can convey useful
information in textual form, such as a brand name or inspection information. The
low or no pressure use indicator
62 may be any geometric shape that is capable
of being altered by low pressure flexing of the tire
16.
FIG. 8A shows a cross section of one exemplary embodiment of the low or no pressure
use indicator
62. Here, the low or no pressure use indicator
62 has
a V-shaped cross section
90. The V-shaped cross section
90 allows
for the concentration of a maximum stress or strain to be imparted on the low or
no pressure use indicator
62. This will cause the cracking or deterioration
of the low or no pressure use indicator
62 to cause the visual indication
to the technician or motorist. FIG. 8B shows another configuration of the cross
section of the low or no pressure use indicator
62. Here, the low or no
pressure use indicator
62 has a substantially V-shaped cross section
202
that has a circular member
92 at an apex
200. Such a cross section
will also allow for deterioration of the low or no pressure use indicator
62
once a low or zero pressure incident occurs. Additionally, the present invention
includes other exemplary embodiments of the low or no pressure use indicator
62
having various cross sections, and the present invention is not limited to a particular
cross section.
The deterioration of the low or no pressure use indicator
62 will be dependent
upon, but not limited to, the geometry, thickness, and/or the angle of the low
or no pressure use indicator
62 relative to the circumferential direction
of the tire
16. It has been found in one exemplary embodiment of the present
invention that placing the low or no pressure use indicator
62 having lines
in the circumferential direction of the tire does not provide for a favorable deterioration,
resulting in a poor indication. Additionally, placing the low or no pressure use
indicator
62 perpendicularly to the circumference also does not provide
for an optimum indication. In one exemplary embodiment of the present invention
the low or no pressure use indicator
62 is placed at a direction from 30
to 80 degrees from the circumferential direction of the tire
16. However,
the present invention includes exemplary embodiments where the low or no pressure
use indicator
62 is placed at the circumferential direction and/or perpendicular
to the circumferential direction.
In another exemplary embodiment of the present invention, the low or no pressure
use indicator
62 may be made of different colored rubber in order to highlight
the deterioration of the low or no pressure use indicator
62. For instance,
the low or no pressure use indicator
62 may be black and once the worn area
70 occurs, the rubber underneath may be red in order to highlight the deterioration.
It should be understood that the present invention provides one subjective indicator
that may be used to indicate the undesirable operation of a tire at low or zero
pressure. As such, it provides an additional but not exclusive way of determining
whether a tire should be replaced.
It should be understood that the present invention includes various modifications
that can be made to the embodiments of the low or no pressure condition indicator
for a tire as described herein as come within the scope of the appended claims
and their equivalents.
*
