U.S. patent application number 10/924004 was filed with the patent office on 2006-02-23 for tire tread wear indicator and molding device for forming a tread wear indicator.
Invention is credited to Anne-France Gabrielle Jeanne-Marie Cambron, Andre Cuny, Frank Severens.
Application Number | 20060037683 10/924004 |
Document ID | / |
Family ID | 35407053 |
Filed Date | 2006-02-23 |
United States Patent
Application |
20060037683 |
Kind Code |
A1 |
Cuny; Andre ; et
al. |
February 23, 2006 |
Tire tread wear indicator and molding device for forming a tread
wear indicator
Abstract
A tire has at least one tread wear indicator. Each wear
indicator is a single mark that provides continuous information to
the consumer, while changing its presentation based upon the amount
of tread wear. The mold blade employed to form the ear indicator
has a series of stacked portions, each portion having a different
configuration, the configuration being constant for the length of
each portion.
Inventors: |
Cuny; Andre;
(Hababy-la-Neuve, BE) ; Severens; Frank; (Arlon,
BE) ; Cambron; Anne-France Gabrielle Jeanne-Marie;
(Angelsberg, LU) |
Correspondence
Address: |
THE GOODYEAR TIRE & RUBBER COMPANY;INTELLECTUAL PROPERTY DEPARTMENT 823
1144 EAST MARKET STREET
AKRON
OH
44316-0001
US
|
Family ID: |
35407053 |
Appl. No.: |
10/924004 |
Filed: |
August 23, 2004 |
Current U.S.
Class: |
152/154.2 |
Current CPC
Class: |
Y10T 152/10027 20150115;
B60C 11/24 20130101 |
Class at
Publication: |
152/154.2 |
International
Class: |
B60C 11/24 20060101
B60C011/24 |
Claims
1. A tire tread for a vehicle tire, the tread having at least one
tread element projecting from the base of the tread and having an
defined tread depth, at least one tread element having a tread wear
indicator, the wear indicator being characterized by: having a
series of radially stacked portions, each portion having a
configuration that visually indicates the tread depth and wherein
each portion has a different configuration.
2. The tread of claim 1 wherein the stacked portions have a
radially innermost portion, and the configuration of the innermost
portion is a warning symbol.
3. The tread of claim 1 wherein at least a single point of contact
is present between radially adjacent stacked portions.
4. The tread of claim 1 wherein the different configurations are
international picture symbols.
5. The tread of claim 1 wherein each portion has a consistent
configuration for the radial depth of each portion.
6. The tread of claim 1 wherein the wear indicator has three
radially outer portions, and the configuration in each of the three
radially outer portions is a face.
7. The tread of claim 1 wherein the configuration of the radially
outermost portion of the wear indicator is a smiley face.
8. The tread of claim 1 wherein the wear indicator has at most five
radially adjacent stacked portions.
9. A molding device for forming a tread wear indicator in a tread,
the molding device comprising a mold blade, the mold blade being
characterized by a series of stacked portions, each portion having
a different configuration.
10. The mold device of claim 9 wherein there is at least a single
point of contact between the stacked portions of the mold
blade.
11. The mold device of claim 9 wherein each portion of the mold
blade has a constant configuration for the length of the
portion.
12. The mold device of claim 9, the mold device further comprising
a pair of pins, the pins being adjacent to the mold blade.
13. The mold device of claim 12 wherein the one pin has a greater
length than the other pin.
14. The mold device of claim 9, the mold device further comprising
a tube surrounding the mold blade.
15. The mold device of claim 14 wherein for at least a portion of
its length, the tube has a circular configuration.
16. The mold device of claim 14 wherein the tube has a changing
cross sectional configuration.
17. The mold device of claim 14 wherein the tube has a cross
sectional configuration that changes at a location corresponding to
a change in configuration of the mold blade.
Description
FIELD OF THE INVENTION
[0001] The present invention is directed towards a tire. More
specifically, the invention is directed to a wear indicator for the
tread of a tire. Also disclosed is a molding device for forming the
wear indicator.
BACKGROUND OF THE INVENTION
[0002] The use of treadwear indicators is not new and the use of
treadwear indicators is mandated by law in many countries. A
variety of such indicators are known. Once such type employs
colored means, such as colored rubber or colored fibers, below the
tread for a visual indicator of wear. Other types use tie-bar type
elements in the tread grooves. When required by law, the upper
surface of the tread wear indicator must be located at a height of
1.6 mm from the base of the groove in which the wear indicator is
located.
[0003] The practical problem with the colored indicators of the
type mentioned is that there is no way for the operator to
determine the level of wear until the tire is worn. When the tire
employs the tie-bar type wear indicator, since the wear indicator
is the same color as the remaining part of the tread, it can be
difficult to determine the level of wear.
[0004] U.S. Pat. No. 6,523,586 discloses wear indicators for a tire
tread wherein, in a series, or predetermined closely located
grouping, of related marks, the marks disappear as the tire is
worn. While this provides continuous information to the consumer,
the complexity of forming the tire is increased due to the need to
form multiple different marks that appear only after a defined
amount of wear.
SUMMARY OF THE INVENTION
[0005] The present invention is directed to a tire comprising at
least one tread wear indicator. Each wear indicator is a single
mark that provides continuous information to the consumer, while
changing its presentation based upon the amount of tread wear. By
forming only a single mark that continuously changes, the
manufacturing of the tire is simplified while still providing the
consumer with the needed information. Also disclosed is a mold
blade used to form the single tread wear indicator. The blade has a
changing configuration based upon the length of the mold blade.
[0006] Disclosed is a tire tread for a vehicle tire, the tread
having at least one tread element projecting from the base of the
tread and having an defined tread depth. At least one of the tread
elements has a tread wear indicator. The wear indicator has a
series of radially stacked portions, each portion having a
configuration that visually indicates the tread depth and wherein
each portion has a different configuration.
[0007] In one aspect of the disclosed invention, the radially
innermost portion of the tread wear indicator is a warning symbol.
The warning symbol may be any symbol that conveys the tread depth
or a warning to the consumer regarding the tread depth.
[0008] In another aspect of the invention, the different
configurations forming the different portions of the tread wear
indicator are international picture symbols.
[0009] In another aspect of the disclosed invention, there is at
least a single point of contact maintained between radially
adjacent stacked portions of the tread wear indicator.
[0010] In another aspect of the invention, each portion of the
tread wear indicator has a consistent configuration for the radial
depth of each portion.
[0011] In another aspect of the invention, the tread wear indicator
has at most five radially adjacent stacked portions.
[0012] Also disclosed is a molding device for forming a tread wear
indicator in a tread. The molding device has a mold blade to form
the tread wear indicator. The mold blade is formed from a series of
stacked portions, each portion having a different
configuration.
[0013] In one aspect of the invention, there is at least a single
point of contact between the stacked portions of the mold blade so
that the blade is a single molding element.
[0014] In another aspect of the invention, each portion of the mold
blade has a constant configuration for the length of the
portion.
[0015] In another aspect of the invention, the mold device has a
tube surrounding the mold blade. The tube may have a constant or
changing configuration; the shape of the tube acting to call
attention to the configuration of the blade after the tread wear
indicator has been formed. Additionally, if the cross sectional
configuration of the tube changes, it changes at a location
corresponding to a change in configuration of the mold blade.
DEFINITIONS
[0016] The following definitions are applicable to the present
invention.
[0017] "Groove" means an elongated void area in a tread that may
extend circumferentially or laterally about the tread in a straight
curved, or zigzag manner. Circumferentially and laterally extending
grooves sometimes have common portions and may be sub classified as
"wide", "narrow", or "sipe". The slot typically is formed by steel
blades inserted into a cast or machined mold or tread ring
therefor. In the appended drawings, slots are illustrated by single
lines because they are so narrow. A "sipe" is a groove having a
width in the range from about 0.2% to 0.8% of the compensated tread
width, whereas a "narrow groove" has a width in the range from
about 0.8% to 3% of the compensated tread width and a "wide groove"
has a width greater than 3% thereof. The "groove width" is equal to
tread surface area occupied by a groove or groove portion, the
width of which is in question, divided by the length of such groove
or groove portion; thus, the groove width is its average width over
its length. Grooves, as well as other voids, reduce the stiffness
of tread regions in which they are located. Sipes often are used
for this purpose, as are laterally extending narrow or wide
grooves. Grooves may be of varying depths in a tire. The depth of a
groove may vary around the circumference of the tread, or the depth
of one groove may be constant but vary from the depth of another
groove in the tire. If such narrow or wide groove are of
substantially reduced depth as compared to wide circumferential
grooves which they interconnect, they are regarded as forming "tie
bars" tending to maintain a rib-like character in the tread region
involved.
[0018] "Inner" means toward the inside of the tire and "outer"
means toward its exterior.
[0019] "Outer" means toward the tire's exterior.
[0020] "Radial" and "radially" are used to mean directions radially
toward or away from the axis of rotation of the tire.
[0021] "Tread" means a molded rubber component which, when bonded
to a tire casing, includes that portion of the tire that comes into
contact with the road when the tire is normally inflated and under
normal load. The tread has a depth conventionally measured from the
tread surface to the bottom of the deepest groove of the tire.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The invention will be described by way of example and with
reference to the accompanying drawings in which:
[0023] FIG. 1 is a portion of a tire tread;
[0024] FIG. 2 illustrates the different portions of a tread wear
indicator;
[0025] FIG. 3 is a cross sectional view of a tread and a tread wear
indicator molding device;
[0026] FIG. 4A is a side view of a molding device;
[0027] FIG. 4B is an end view of a molding device;
[0028] FIG. 4C is a perspective view of the blade of the molding
device; and
[0029] FIG. 5 is an alternative configuration for a portion of the
wear indicator.
DETAILED DESCRIPTION OF THE INVENTION
[0030] The following language is of the best presently contemplated
mode or modes of carrying out the invention. This description is
made for the purpose of illustrating the general principles of the
invention and should not be taken in a limiting sense. The scope of
the invention is best determined by reference to the appended
claims. The reference numerals as depicted in the drawings are the
same as those referred to in the specification. For purposes of
this application, the various embodiments illustrated in the
figures each use the same reference numeral for similar components.
The structures employed basically the same components with
variations in location or quantity thereby giving rise to the
alternative constructions in which the inventive concept can be
practiced.
[0031] FIG. 1 illustrates a portion of a tire tread. The tread has
a plurality of blocks 10 defined by circumferential and lateral
grooves 12, 14 and a rib 16 located on the centerplane of the tire.
The exact configuration of the tread is irrelevant to the present
invention and any tread configuration may be employed.
[0032] Located in at least one of the tread elements, either a
block 10 or the rib 16, is a single wear indicator 20. The wear
indicator 20 is located in the tread in such a manner as to make
contact with the road surface as the tire rotates, even when the
tire is new and unworn. While the illustrated wear indicators 20
are present along an almost lateral line across the tread width,
this is not required and the wear indicators 20 may be
circumferentially spaced along the tire tread, i.e. it is not a
requirement of the present invention to have a series, or
predetermined closely located set, of the wear indicators.
[0033] When unworn, the wear indicator 20 has a configuration
indicating that the tread depth is unworn. The configuration may be
any type of configuration that readily communicates this to the
consumer. A preferred configuration is the smiley face enclosed in
a circle 22, see FIG. 2A. As the tread is worn, the configuration
of the wear indicator 20 as seen by the consumer changes. After
approximately one-third of the working tread depth, see line A in
FIG. 3, is worn, the working tread depth being that which the
appropriate governing authorities (such as NHTSA in the U.S.A.)
deem to be appropriate or required for safety, the configuration
changes from a smiley face 22 to a neutral face 24, see FIG. 2B.
The neutral face 24 configuration is present until the working
tread depth is worn approximately another third, line B of FIG. 3.
At approximately two-thirds wear of the working tread depth, the
neutral face 24 changes to a frowning face 26, see FIG. 2C. After
the remaining third of the working tread depth is worn, line C of
FIG. 3, and the tread level has reached the point considered unsafe
by the appropriate governing authorities, the configuration again
changes, from a frowning face 26 to a warning mark, such as the
illustrated exclamation mark in a triangle 28, see FIGS. 2D and 3.
The final configuration may be selected as any international
picture mark recognized as a warning mark for consumers.
[0034] The predetermined wear levels at which the different
configuration is visible may be selected at levels other those
mentioned above. For example: the initial smiley face 22 may be
present for less than a quarter of the initial useful life of the
tread depth, the neutral face 24 may last for the next fifty
percent of the initial useful life of the tread depth, and the
frowning face 26 may last for the final quarter of the initial
useful life of the tread depth.
[0035] Alternatively, the warning mark 28 may be selected to appear
at a point wherein there is still tread remaining in the useful
life of the tread depth D, so that the tire may still be considered
to have sufficient tread life remaining to give the consumer time
to replace the tire. One possibility is that the different
configurations each last for one-fourth of the useful life of the
tread depth D.
[0036] Since the different configurations appear consecutively as
the tread is worn, for ease of manufacturing, the different
symbols/configurations are formed in the tread by a single molding
device 30, see FIGS. 4A-4C. The molding device 30 is formed from a
tube 32 having internal pins 34, 36 and a blade 38. The molding
device 30 is formed from conventional mold materials, such as
steel, aluminum, or pressed metal.
[0037] The tube 32 forms the circle and triangular portions of the
tread wear indicator 20. The majority of the tube 32 is circular,
with one end having a triangular configuration to correspond to the
triangular portion of the warning sign. The tube 32 has a length
greater than the depth of the tread wear indicator as a portion of
the tube 32 is used to secure the molding device 30 in the tread
mold. Forming the two eyes of the different faces, and the point to
the exclamation mark, are two pins 34, 36. The pin 34 which forms
one eye and the exclamation mark point has a length greater than
the other pin 36.
[0038] To form the changing mouth configuration of the faces 22,
24, 26 and the exclamation mark, a stacked blade 38 is located
inside the tube 32. The first portion 38a of the blade 38 is curved
to form the smiling mouth, the next portion 38b is straight to form
the neutral mouth, the third portion 38c is curved to form the
frowning mouth, and the remaining portion 38d is straight to form
the exclamation mark. A point of contact 40 is maintained between
adjacent portions 38a, 38b, 38c, 38d so that a single blade 38
results.
[0039] When assembled, the stacked blade 38 and pins 34, 36 are
located inside the tube 32, and the tube 32 is mounted to the
inside of the tread mold.
[0040] Because of the changing configuration of the molding device
30 and the blade 38 therein, samples were made using a tread
compound block and a sample molding device 30. To simulate the
worst case for rubber extraction, a summer compound (i.e. a stiffer
compound) was used was testing. The samples tested fine, showing
the different configurations at the preset tread depths. The
molding device 38 was formed with a thickness equivalent to a
conventional sipe blade.
[0041] As noted above, other international symbols may be used to
designate the different wear levels of the tread. FIG. 5 shows the
circular crossed symbol 42; known as the symbol for "no" or a
non-permitted activity. When using this symbol 42 as the final
warning symbol in the tread wear indicator, the tube 32 of the
molding device 30 would remain a circular tube for its entire
length. Alternatively, a simple warning triangle may be used
instead of the frowning face 26 to indicate a warning, with the
final configuration including the emphasis of the exclamation mark
within the triangle.
[0042] Alternatively, the stacked blade 38 may be used to create a
stack of numbers indicating the tread wear level. The main
requirement in forming the molding device is that there be at least
one point of contact 40 between the different configurations, or
blade portions, so that the molding device 30 can be readily
inserted into and extracted from the tread rubber. This does
require the selected numbers, or other indicators, be as simple in
configuration as possible and precludes having numerous, preferably
not more than 5 different, configurations forming the stacked blade
38. Also, the stacked blade 38 may be used without an external tube
32; the presence of the circle and the triangle merely assist in
calling attention to the tread wear indicator.
[0043] The present invention is directed towards a tread wear
indicator that provides for a changing configuration in the tread
wear indicator based on the tread wear. The disclosed indicator
provides for continuous and progressive indication of the tread
wear. When formed in the preferred method of using a stacked blade,
the complexity in forming the mold and the molding of the tire is
significantly reduced to conventional series of tread wear
indicators that provide progressive indication of the tread
wear.
* * * * *