Note: Descriptions are shown in the official language in which they were submitted.
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Back~round ~C 3~ CI
This invantion relates to a pneumatic tire and~
more particularly~ to a tublesss pneumatic tire having
means for preventing air retention when the tire is mounted
on a wheel having a rim diamlter smaller than that ~or
which it was designed.
Pneumatic tirss come in a variety of sizes and are
generally designed to be used with a particular wheel size.
When a tire is mounted and infla-ted on the size wheel for
which it was designed~ the bead portions of the tire engage
the bead seats and rim flanges o~ the ~heel in a secure
manner~ forming arL airtight seal between the bead portlon
of the tire and the bead seat of the rim. Proper bead
seating is essential in a tubeless-type tire Prom the
standpoint of tire performance and safety of the occupants
of a vehicle on which the tires are mounted~
With the large selection of tubeless tire and wheel
sizes9 there egists the possibility that a tire may be
incorre¢tly mounted on a wheel having a ri~ diameter-
slightly smaller than that for which it was designed.
Although the bead portions o~ the tire will not properly
seal~ in~lation o~ the tire may occur due to the sealing
engagement of the axial outer sur~ace of the bead portions
of the tire with the flanges of the rim. Howe~er~ this
type of sealing engagement is insecure and may lead to
premature faillLre o~ the tire~ thus~ causing possibly
in~ury to the occupants o* the vehicle and/or damage to the
tire itself. This type o* mismounting is~ o~ course~
limlted to wheels having a rim diameter smaller than that
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for which the -tire was designed, bu-t large enough to
permi-t sealing be-tween -the rim flange and side of the
bead portion of the tire.
According -to one aspect of the presen-t invention,
there is provided a tubeless pneumatic tire comprising:
a pair of bead portions having a plurality of circum-
ferentially spaced ribs ~or preven-ting sealing engage-
ment of said -tire when mounted on a wheel having a rim
diameter smaller than the diameter of the wheel onto
which the -tire was designed to be used with by providing
a plurality of air passages for escape of inflation
pressure, said ribs extend substantially radially out-
ward with respect to the axis of said tire along the
exterior surface of the lower part of each o~ said bead
portions starting from approximately the nominal rim
diameter o~ said tire such that when said tire is mounted
on wheel for which it is designed for use and the tire
; is in~lated to normal inflation pressures said ribs at
least in part will be in abutting relationship with the
axial inward surfaces of the flanges of said rim, the
toe bead surface of said tire forms an angle from
about 10 to 20 with respect to a line parallel to
~ the rotational axis o~ said tire.
- In accordance with another aspect of the present
invention, there is provided a me-thod o~ preventing a
tire having a given bead diameter designed ~or operative
mounting on a first wheel o~ a firs-t rim diameter from
being operatively mounted on a second wheel of a second
rim diameter less than said ~irst wheel of said ~irst
rim diameter by preventing the exterior sur~ace of the
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bead por~tion of said -tire from ~orming a sealing
relationship with the flanges o~ said second wheel
by permi-t-ting leakage of inflation air between said
tire and said second wheel comprising: providing on
the exterior surface of said lower bead portion of
said tire a plurality o~ circumferen-tially spaced
projections or depression.s which e~tend substantially
radially outwardly with respect to the axis o~ the
tire starting from approximately nominal rim diameter
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of said tire, said projections or depressions form ,-
a plurality of air passages when mounted on said
second wheel permitting leakage o~ infla-tion air.
thereby preventing said,tire from forming a sealing '.
,. engagement with said second wheel; '
further prw iding means for preventing air flow ,~
from the internal cavity o~ said tire and from formlng `'
an air sealing relationship with said bead seat portions
of said first wheel when said tire is operatively ~ :
mounted thereon, said second means being located in
the radially innermost portion of said bead portion ~'
and belng located radially inward and axially in~ard ~, -
of said projections and depressions.
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: , Descr ption of the Drawings
Fig. 1 is a fragmentary transverse sectional view
showing the preferred embodiment of the invention
mounted on a wheel having the correct rim diameter
size for which it was designed;
,
. Fig. 2 is a fragmentary side view o~ a tire made
in accordance with the present invention taken along
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line 2-2 o~ Fig. l;
Fig. 3 is a cross-sec-tional view of a tire made
in accordance wi-th the presen-t invention taken along
line 3-3 of Fig. 2;
: Fig. 4 is a fragment;ary, transverse sectionalview of a tire according to the pre~erred embodiment
o~ the present invent on mounted on a wheel having a
rim diameter smaller than that for which it was de-
signed; and
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Fig. 5 is a fragmentary cross-sectional view simllar
to that o~ Fig. 3 illustrating a modifie~ form of the
present invention~
Referring to Fig. 1~ there is illustrated a tire 10
made in accordance with the present in~ention mounted on
a wheel having a rim 12 for which it was deslgned~ The
rim 12 comprises a pair of axially spacad flanges 14~ 16
which extend annularly around the wheel. The radially
inner ends of the flanges 14~ 16 merge into a pa~r of bead
seats 18~ 20~ respectively. The rim 12 further comprises
an annular wheel-portion 22 spaced axially inwardly
from the bead seats 18~ 20.
The tire 10 is provided with bead portions 26~ 28
such that when the tire is mounted on a wheel 12 for which
it was designed~ the bead portlons 263 28 are in buttlng ;~
relationship with flanges 14~ 16~ respectivel~ the toe
portions 27~ 29 of the tire 10 forming an alrtight seallng
ralationship with bead seats 18; 20~ respectivslyO The
tire 10 is of the tubeless typa and may be of a radial or
bias ply constructions.
The exterior surface of bead portions 26, 28 is
provided with a plurality of radially extonding projections
or deprassions which extend Xrom the lower portion of bead
portions 26~ 28 radially outward along the ext~rior side-
wall surface of tire 10. Reforring to Flgs. 1 through
the preferred embodiment of the present invantion is
provided with a plurality of ribs 30~ The radially inner
end 32 of ribs 30 start at a point on bead portions 26~ 28
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such that the tire 10 when mounted on a wheel having a
rim diameter smaller than that for which it was designed
(as shown in E'ig. ~) will prevent inflation of the tire.
In particular, the present invention is designed to prevent
inflation o~ a tire on a rim diameter which is approxi-
mately 1/~ of an inch (6.248 mm) to 3/4 of an ihch
(19.05 mm) less in diameter than that for which the tire
was designed to be used with. The ribs 30 should not
extend radially inward as to interfere with proper bead
seating and sealing of the tire on the rim fo~ wh~ch it was
designed (as illustrated in Fig. 1). Preferably7 the
ribs 30 do not extend radially inward of the bead heel
sharp point.
Tha radially outer end 34 of ribs 30 may extend to
any point desired along the exterior surface of the tire.
The end 3~ should extend radially outward a distance so
that the ribs will prevent the exterior surface of the
lower bead portion of the tire from sealing with the rim
~langes of the rim. The exterior surface o~ the tire 10
in betweenithe ribs 30 should be free of any substantially
circumferentially extending projection or projections.
The number of projectlons or depressions necessary
will vary upon the size of the tire and the cross-sectional
c~nfiguration and size of the projections or depressions.
There should be a sufficient number of projections or
depressions to prevent the bead portions 26~ 28 from form- -
ing a sealing engagement with fl~nges 14~ 16.
In the particular tire illustrated in Figs. 1 through
3~ the ribs 30 are circumferentially spaced approximately
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an inch apart~ are semi-circ~lar in cross-sectional
configuration and extend from a point radially outward
from the nominal rim diamete;r NRD of the tire a distance
equal to approximately 0.5 inches (12.7 mm) and extends
radially outward along the exterior sur~ace of the tire
10 a distance equal to about 0.5 inches (12.7 mm). The
ribs 30 have a width W, and a height H, equal to
approximately 0.030 inches (0.762 mm). Various other
sizes and configurations may be used so long as they do
not interfere with proper bead seating.
The tire bead toe surfaces 31, 33 when in the mold in
which it is cured form an angle from about 10 to 20~
pre~erably 15 with a line parallel to the rotational axis
of the tire 10.
The bead sea-ts 18, 20 of wheel 12 for which the tire
10 was designed are inclined outwardly and typicall~ have
an angle of a few degrees~ that is, from about 2 to 10~
preferably about 5~ as measured between a plane parallel
to the rotational axis of the tire 10 and passing along
th~ surface of the bead seats.
Referring to Fig. 4~ there is illustrated a tire 10
made in accordance with the present invention mounted on
a wheel 13 having a rim diameter less than the rim for
which it was designed.
For the purpose of clarity~ only one hal~ of the wheel
13 is illustrated~ the other half not shown being identical
to the axial end shown. It should therefore be understood
all that is said with respect to the half illustrated
applies equally to the half not shown. The flange 15
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extends annularly around the wheel 13~ the radially inner
end merging into a bead seat 19. The radial height of
flange 15 of wheel 13 is such that the radially outermost
point extends radlally outward from the axis of the wheel
13 a distance equal to about the distance in which the
radially outermost point of flanges 1~, 16 of wheel 12
extend from its respective axis.
Ribs 30 prevent the bead portions 26, 2& of the tire
10 from formlng a sealing engagement with flange 15 of the
wheel 13 by allowing air to escape from the internal
cavity of the tire 10 outward along the exterior part of
tire 10 to the atmostphere~ as is indicated by the arrows
in Fig. ~
Referring to Fig. 5, there is illustrated an
1~ alternate embodiment of the present invention. In place
of the ribs 30 shown in Fig. 3~ grooves ~0 are provided in
the lower bead portion to prevent the tire from forming a
sealing engagement with flanges 1~ 16. The grooves 40
start from the same lower limits as ribs 30 and extend
radially outward along the surface of the tire 10 termin-
ating in the same manner as ribs 30. The grooves 40 have
the same width W and height H as grooves 30.
- While certain representative embodiments and details
have been shown for the purpose of illustrating the inven-
-25 tion~ lt will be apparent to those skilled in this art that
various changes and modifications may be made therein
without departing from the spirit or scope of the invention.
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