Note: Descriptions are shown in the official language in which they were submitted.
37
This invention relates to tire assemblies and, more
particularly, to a shield which is removably interposed
between the tire rim and tire flap to prevent flap wear and
tire blo~outs.
Over the years, various improvements have been
made to vehicle tires. These improvements have been
directed primarily toward increasing the useful life of
tires and reducing or eliminating operational tire
failures such as blowouts, punctures, ply separations,
10. and the like, thereby improving the safety of vehicular
operation.
One area in which improvements have been directed
is in the prevention of inner tube failure caused by the
tube's interaction with the rim. For example, the invention
disclosed in U.S. Patent 1,658,646 sought to reduce inner
tube failures through the use of an improved tire flap.
In recent years, there has been a reduction in the
use of inner tubes for tires on light-duty vehicles, such as
passenger cars. As a result, the largest present use of
20. inner tubes in tires is in heavy-duty applications such as
trucks, buses, and semi-trailers. Many of the recent
developments in the art have been directed toward these
applications. U.S. Patents 3,533,461 and 4,063,584 both
disclose tire flaps for heavy-duty vehicles which include
improvements for reducing the wear on the inner tubes caused
by the squeezing or pinching of the tubes between the flap
and the tire of the wheel assembly. U.S. Patent 2,773,535
discloses a metal plate which is incorporated and embedded in
the tire flap during molding to reinforce the flap adjacent
30. to the valve stem opening and to provide a rigid seat for the
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flanged end of the valve stem so as to prevent undesirable
cocking and distortion of the valve stem~
Other devices have been added to Eix the position
of the valve stem, or to prevent the stem from being drawn
into the tire when the inner tube deflates. Among these
devices are those disclosed in U.S. Patents ~,580,343;
2,968,206; 3,106,953; and 3,077,220.
Recent developments have significantly affected
heavy-duty vehicular operations. These changes have at least
10. indirectly helped create some of the problems which the
present invention solves. Many states now permit trucks and
other heavy-duty vehicles weighing up to 80,000 pounds gross
to operate on the roads. Operators of these heavy-duty
vehicles are also now inflating their tires to pressures in
the range of 100-110 psi, since it has been shown that higher
tire pressures conserve increasingly expensive fuel and
extend the useful life of costly tires.
Increased loads, and increased tire pressures has
resulted in tire failure from sources not often encountered
20. with lighter loads, and lower pressures. In particular, the
pressure now exerted by the inner tube against the tire flap
tends to force portions of the tire flap through the valve
stem opening in the wheel rim. This deformation eventually
causes the tire flap to either wear thin or crack around the
valve stem opening in the flap. The weakening of the tire
flap results in stress being placed upon the inner tube,
which, if the tire flap is not replaced, will ultimately
result in failure and deflation of the inner tube. Besides
the obvious safety hazards presented by a deflating tire
during the operation of a heavy-duty vehicle, the tire itself
t73~
may be destroyed. When a tube tire on a moving vehicle is
suddenly deflated, an extremely large force is exerted upon
the inner tube valve stem before the vehicle can be brought
to a stop. Frequently, this force is great enough to draw
the vàlve stem inwardly through the valve stem opening into
the tire. Not only can this damage the valve stem, but the
presence oE the valve stem within the tire often damages the
tire and the inner tube beyond repair before the vehicle can
be brought to a halt.
10. Another way in which tire flaps can be damaged
is through exposure to water, road salts, greases, oils,
and road chemicals which weakens the rubber material of
the flaps, and eventually causes them to deteriorate and
break or crack. The flaps are protected in large part from
these elements by the wheel rim. ~owever, most wheel rims
ror heavy-duty vehicles have an elongated slot which is
typically about .750 inch (1.905 cm) wide and 3.75 inches
(9.525 cm) long for receiving the valve stem of the inner
tube, leaving an unprotected area of the flap around the
20. valve stem.
Standard industry practice is to reuse tire flaps a
number of times. Because most of the tire flap is hidden
from view, it is usually difficult to determine when the flap
is wearing out, unless the tire is removed from the rim.
Therefore, too often, tire flaps are not replaced before they
have been damaged or become worn to the point where the inner
tube ruptures and deflates.
Because of the number of flaps, inner tubes, and
rims currently in use, it would be both impractical,
30. wasteful, and extremely expensive to rectify the
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above-described problems by discarding viable present components
and replacing them with improved components. It would be pre~
ferable to alleviate these problems with a device which is
inexpensive, easy to install, and readily adapted to be used
with equipment presently in service.
It is therefore an object of this invention to provide
a reusable shield which may be interposed between the tire flap
and the wheel rim to prevent deformation of the tire flap into
the elongated valve stem opening in the wheel rim.
The invention provides in a tire and wheel assembly
of the type including a wheel rim, a tire and an inner tube
having a valve stem projecting through the wheel rim, an
elongated opening in the wheel rim for receiving the valve stem,
and a flap disposed between the wheel rim and the inner tube to
provide protection for the inner tube surface adjacent the wheel
rim, the flap including a central portion and side portions, the
improvement comprising a shield interposed between the flap and
the wheel rim, completely covering the opening in the wheel rim
to shield the flap from exposure to exterior substances such as
grease and oil through the opening, the shield being constructed
of a lightweight material which resists deterioration when exposed
to the substances such as grease and oil, the shield including a
central portion and flanges extending over the side portions of
the flap in proximity to the rim opening, the shield having a
width such that its flanges extend at least partially along -the
side portions of the flap to protect the side portions and pre-
vent rotation of the shield about the valve stem, and the central
portion of the shield including a relatively small opening for
snugly receiving the valve stem.
The shield prevents the valve stem from being drawn
into the tire casing through the valve stem opening in the rim
when the inner tube is deflated and is inexpensive, easy to
.,~
7~'~
install, and readily adaptable to tire flaps and wheel assem-
blies presently in use.
The invention will best be understood by reference
to the appended drawings forming a part of this specification
and which illustrate a preferred embodiment thereof, wherein:
Figure 1 is an exploded view of a tire and wheel
assembly, with all parts shown in their proper relationship;
Figure 2 is a sectional view taken generally along
section lines 2-2 of Figure l; and
Figure 3 is a top plan view of a tire flap showing
damage and deterioration which has heretofore occurred in tire
and wheel assemblies.
Referring now to Figures 1 and 2, a typical tube tire
and wheel assembly 10 includes a wheel rim 12 having a
cylindrical cen-ter section 14 which includes an elongated slot
or opening 16 for receiving the valve stem 18 of an inner tube
20. In most assemblies 10 used on heavy-duty vehicles, the
center section 14 is 8 inches (20.32 cm) wide and the opening
16 is 3.75 inches (9.525 cm) long and .750 inch (1.905 cm) wide.
The valve stem 20 includes at its distal end a
threaded opening with air valve 19, through which air is intro-
duced into the inner tube 20. The tube 20 is inserted into a
tire 22 which is in turn mounted upon the rim 12 and the tube
20 is inflated to a sufficient air pressure. An inner flap 24
is positioned between the tube 20 and the cylindrical center
portion 14 of the rim 12 to protect and provide support for the
tube 20 against the rim 12. The flap
7~:3';'
24 includes an aperture 26 which is substantially smaller
than the elongated slot or opening 16 provided in the wheel
rim 12 for receiving the valve stem 18 of the tube 20.
Because of the size of the elongated slot or opening 16 in
the rim 12, a portion of the flap 2~ in proximity to the
valve stem 18 of the inner tube 20 is exposed through the
valve stem opening 16 in the wheel rim 12. The flap 2~ is
typically constructed of a rubber material. ~eretofore, with
the exposure to water, road salts, greases, oils, and other
10. road chemicals through the slot 16, these flaps 24 have
deteriorated and worn so that they eventually cannot
withstand the tire pressure.
As shown in Fig. 3, the flap 24 may become so
weak that the air pressure within the tube 20 forces a
portion 23 of the flap 24 into the opening 16. As the
flap 24 becomes weaker and weaker through exposure to the
elements, the tube 20 projects further and further into
the opening 16 until finally the portion 23 of the flap 24
in proximity to the valve openings 16 and 26 ruptures due
20. to the internal air pressure in the tube 20. The rupture
of the flap 24 may in turn rub or pinch the tube 20 and
cause it to deflate. This rupture and eventual deflation
of the tube 20 may either be gradual or in some instances
rapid to create a blowout and a hazardous driving
condition. Further, when the flap 24 ruptures and tube 20
deflates, the stem 18 may be drawn into the tire 22
through the elongated opening 16 and the aperture 26 in
the flap 24. When this happens, the stem 18 usually gouges
the interior of the tire 22 so that the tire 22 is many
30. times destroyed.
7~7
Another way in which the flap 24 may be rendered
unusable is the development o cracks 29 in the flaps 24
around the weakened portion 23 of the flap 24 in proximity to
the valve openings 16 and 26. The weakening of the portion
23 of the flap 24 is produced by either the high air pressure
in the tube 20, exposure to water, road salts, greases, oils,
and road chemicals which are introduced to the flap through
the opening 16, or a combination of both of these factors.
The exposure of the area 23 to the outside elements serves to
10. speed up the processes which result in flap 24 rupture and
; cracking.
Referring back to Figs. 1 and 2, the improved tire
and wheel assembly 10 of the present invention includes a
shield 30 having an aperture 31. The shield 30 is interposed
between the flap 24 and the cylindrical center portion 14 of
the wheel rim 12 in proximity to the opening 16. The shield
30 is an oblong sheet of plastic or other resilient material
which is not affected by exposure to elements such as water,
road salt, greases, oils, and other road chemicals, and which
20. is strong enough to resist deformation due to tire pressure.
In a preferred embodiment, the shield 30 contains a contoured
center portion 32, which fits flush against the center
portion 14 of the rim 12 and the tire flap 24. The shield 30
further includes flanges 33, 34 on either side of the center
portion 32 which fit flush against the flanges of the wheel
rim 12 and the tire flap 24 in proximity to the valve stem
openings 26, 16. The flanges 33, 34 of the shield 30 serve
to position and prevent the shield 30 from rotating about the
valve stem 18 relative to the flap 24. The shield 30 covers
30. the area 23 of the flap 24 in proximity to the valve stem
openings 16, 26 to shield the area 23 from exterior elements
and also prevent the flap 24 and tube 20 from projecting
through the opening 16 in response to internal tire pressure.
The shield 30 therefore serves to cover the valve stem
opening 16 in the wheel rim 20. The shield 30 of the present
invention is constructed as a unit separately from the tire
flap 24 so that it is reusable and removable independently of
other components of the tire and wheel assembly 10. A new
shield 30 may be inserted at any time, without necessitating
10. a change of any of the other components of the tire and wheel
assembly 10 or may be repeatedly used even though the tire
flap 24 or other components of the tire and wheel assembly 10
are changed.
The use of shield 30 permits a conventional valve
stem cap 40, when screwed to air valve 19 of valve stem 18,
to prevent the stem 18 from being drawn into the interior of
the tire 22 when the tube 20 is deflatinq during operation of
the vehicle. This feature prevents the stem 18 from gouging
or causing other serious damage to the tire 22 when a blowout
20. occurs.
Further, since the shield 30 is fabricated from a
lightweight resilient material, the addition of the shield 30
to a tire and wheel assembly 10 does not create an imbalance
problem.
