This invention relates to a rim protector for vehicle wheels,
particularly but not necessarily exclusively for alloy wheels for cars.
It is known to provide vehicles such as cars with alloy
wheels. These wheels are generally made of an aluminium or magnesium alloy although
the term is sometimes extended to include any non-steel wheel. Alloy wheels are
generally lighter than the corresponding steel wheels, and are also considered to
be more attractive.
However, alloy wheels are particularly prone to damage
due to impacts with, for example, kerbs at the side of roads. This is because they
are softer than steel wheels. Particularly damaging can be incidents where the vehicle
wheel strikes a kerb whilst the vehicle is travelling at speed. This can easily
scuff or chip the alloy wheels. The rim of the wheel is most as risk, given that
it is the part of the wheel that protrudes furthest horizontally from the car.
We are aware of the UK Patent Application publication
GB 2 393 940, which
discloses a rim protector for an alloy wheel, which comprises an annular element
with a portion trapped, in use, between the tyre and the wheel and a head portion
that overlaps the rim of the wheel. The head extends further outwards from the axis
of rotation of the wheel than inwards.
We are also aware of United States Patent Number
5 967 212, which discloses
a rim protector according to the pre-characterising portion of claim 1. United Kingdom
Patent Applications Numbers GB 2 403
696 and GB 2 397 561
disclose similar devices. According to a first aspect of the invention, there is
provided a rim protector for a wheel of a vehicle, the rim protector being of the
form of a generally circular annulus having an axis defining radial and axial directions,
the rim protector comprising a tail portion, sized to fit in use between the wheel
and a tyre fitted to the wheel, and a head portion, the head portion being wider
than the tail portion, the tail portion extending away from the head portion, in
which, when the rim protector is fitted to a wheel such that the tail portion is
held between the wheel and the tyre and the head portion abuts a rim of the wheel,
the head portion overlaps the rim and extends further radially over the rim than
it does over the tyre.
This has been found to have several possible advantages
over prior art devices, such as that disclosed in GB2
393 940. The inventors have appreciated that with prior art devices
where the head portion extends further over the tyre than the rim, the tyre side
of the protector will most likely come into contact with a kerb first as it is the
outermost portion of the protector. The head portion will therefore act as a lever,
pivoting about either the junction of the head portion with the tail or where the
head portion engages the rim.
The further the head portion extends in the radial direction,
the greater the moment applied by the head portion at its junction with the tail
portion. Given that this point, where the width of the device changes, will inherently
be a weak point, this magnification of forces can lead to the head of the protector
tearing away from the tail portion, damaging the protector so that it requires replacement.
By reducing the amount by which the head portion extends over the tyre, this magnification
effect is reduced.
Furthermore, the inventors have realised that the relatively
rigid rim of the wheel is more susceptible to impact damage than the relatively
resilient tyre wall. The rim therefore requires greater protection than the tyre,
which can be achieved by having the protector extending further over the rim than
The head portion preferably has a tyre-engaging surface
which, in use, engages the tyre and a rim-engaging surface which engages the rim
of the wheel. The tyre-engaging surface may be shaped so that pressure from the
tyre on that surface forces, in use, the rim-engaging surface against the rim. This
ensures that the rim of the wheel is protected. Typically, the tyre-engaging surface
will be curved, and may form part of the junction between the tail and the head
The head portion may be provided with an impact surface,
on the side that is radially outward in use. This impact surface may be sloped so
that, when the rim protector is fitted between a tyre and a wheel, when moving radially
inwards the impact surface slopes axially outwards away from the tyre. Preferably,
this has the effect, in use, to deflect any impacts axially outwards away from the
wheel. The head portion may also be provided with a rubbing surface, which lies
in use generally in an axial plane over the rim. This surface may act as a "sacrificial"
surface, which takes any abrasion which would otherwise scratch the rim.
The impact and rubbing surfaces may be shaped so that,
in use, the radially outmost impact surface deflects any impacts axially outwards
onto the rubbing surface. Typically, when fitted between the wheel and tyre, the
impact surface will be on the part of the head portion over the tyre, whilst the
rubbing surface will be over the rim. When fitted to a wheel, the head portion may
be thicker axially over the rim at the rubbing portion than at the impact portion
over the tyre.
The rim protector is preferably formed from a resilient
material. This has been found to have good impact protection.
The tail portion may be provided with at least one ridge
on the side that, in use, engages the tyre; the ridge may provide extra frictional
engagement with the tyre.
Preferably, when the rim protector is fitted to a wheel,
the axis is coaxial with the axis of rotation of the wheel.
The tail portion may be provided with a ridge on the side
that, in use, engages the wheel at the end thereof that connects to the head portion.
This ridge may be sized and positioned so as to define, in use, the edge of the
contact between the tail portion and the wheel, and such that, when installed on
the wheel there is a gap between the head portion and the rim of the wheel.
Such a gap means that dirt that works between the head
portion and the rim will not generally be forced to abrade the rim of the wheel.
The rim protector may be provided with reference indicia
indicating where a user should cut away an arc of the rim protector in order to
fit the rim protector to wheels of different sizes. As such, whilst the circumference
of the annulus rim protector may be continuous, in the alternative it is not. By
breaking the rim protector, it can be installed on a tyre without removing it wholly
from the wheel, making installation much simpler.
According to a second aspect of the invention, there is
provided a vehicle wheel, fitted with a tyre and a rim protector according to the
first aspect of the invention, wherein the tail portion of the rim protector is
held between the tyre and the wheel and the head portion extends further radially
over the rim of the wheel than it does over the tyre.
Preferably, the rim of the wheel has a maximum outer diameter
which contacts the rim protector at a given point; where the rim protector is formed
from a resilient material, the internal diameter of the rim protector at the given
point when it is not fitted to the wheel is preferably smaller that the maximum
outer diameter of the rim. This allows the rim protector to be held onto the wheel
by elastic forces; the rim protector can be a stretch fit on the wheel. The difference
in diameter may only be small; preferably, the internal diameter of the rim protector
at the given point is between 6 and 10mm, 7 and 9mm or substantially 8mm less than
the maximum outer diameter of the rim.
The wheel is preferably a wheel of a car, but may alternatively
be the wheel of a motorbike, pedal bicycle, goods vehicle, bus, taxi or other rubber-wheeled
vehicle. The rim protector may be substantially cylindrically symmetrical about
According to a third aspect of the invention, there is
provided a method of installing the rim protector of the first aspect of the invention
onto a vehicle wheel having a tyre installed thereon, comprising providing the rim
protector having a non-continuous circumference, forcing one end of the rim protector
between the tyre and the wheel, and then working the length of the rim protector
between the tyre and the wheel.
Doing this does not require the entire tyre to be lifted
off the wheel, and so can be carried out by an end user using little more than,
say, a rubber mallet. It is also quicker than having to remove the tyre from the
The step of providing the rim protector may comprise cutting
an arc out of the rim protector in order to provide a rim protector to fit a desired
size of wheel. This is very useful, as it allows a single size of rim protector
to be used on multiple different sizes of wheels. It is advantageously combined
with the provision of indicia indicating where the arc should be cut out of the
rim protector for the different sized wheels.
The method may also comprise the step of filling any gap
between the ends of the rim protector with a sealing compound. This ensures dirt
does not become trapped, and can provide a consistent cosmetic finish if the sealing
compound is the same colour as at least a portion of the rim protector.
In the preferred embodiment, the method comprises the step
of deflating the tyre, preferably fully, before forcing the first end of the rim
protector onto the wheel. Similarly, the method may comprise the step of reinflating
the tyre once the rim protector has been fully installed thereon.
There now follows by way of example only description of
embodiments of the invention, described with reference to the accompanying drawings,
- Figure 1 shows a cross-sectional
view of a rim protector according to a first embodiment of the invention, fitted
to the wheel of a car;
- Figure 2 shows a cross-sectional
view of the rim protector of Figure 1 before
it is fitted to a wheel;
- Figure 3 shows a cross-sectional
view of a rim protector according to a second embodiment of the invention, fitted
to the wheel of a car;
- Figure 4 shows a cross-sectional
view of the rim protector of Figure 3 before
it is fitted to a wheel;
- Figure 5 shows a cross-section
view of the rim protector of Figure 3,
showing a larger area of the tyre and wheel;.
- Figure 6 shows a cross-sectional
view of the rim protector of a third embodiment of the invention, fitted to a wheel;
- Figure. 7 shows a cross-sectional
of the rim protector of Figure 6, before
it is fitted to a wheel;
- Figure 8 shows the rim protector
of Figure 6 depicted with different head
portion shapes; and
- Figure 9 shows a plan view of
a rim protector of a fourth embodiment of the invention.
The accompanying drawings depict two embodiments of rim
protectors according to the various aspects of the invention. It is to be noted
that the items depicted - the wheel, tyre and rim protectors - all have cylindrical
symmetry about the axis of rotation of the wheel 1, and so the view in cross section
of one side is sufficient to determine the shape of the entire device, as the cross
section is taken through the plane containing the axis 1. The axis 1 defines a radial
direction, perpendicular to the axis, and an axial direction parallel to the axis.
The rim protector 10 according to a first embodiment of
the invention is shown in Figures 1 and 2
of the accompanying drawings. The rim protector 10 comprises a head portion 11 and
a tail portion 12 and is formed of a resilient, semi-rigid plastics material. The
head portion 11 is of generally square outline in cross-section, with rounded edges.
The tail portion 12 depends from the head portion 11 at a corner thereof; when the
rim protector is not installed on a wheel as depicted in Figure
2 of the accompanying drawings it extends away from the head portion 11
forming a continuous extension to one of the sides. The width 13 of the head portion
11 is much greater than the width 14 of the tail portion 12.
In use, the rim protector 10 is installed between the tyre
2 and wheel 3 of a vehicle such as a car as shown in Figure
1 of the accompanying drawings. The tail portion 12 is stretched over the
outside of the wheel 3, leaving the head overlapping the rim 4 of the wheel 3. The
internal diameter 20 in the uninstalled state of the head portion at the point where
it engages the rim 4 at the largest part of the wheel 3 is approximately 8mm smaller
than the external diameter of the wheel 3 at that point; the resilient material
from which the protector is formed therefore allows for a stretch fit.
The tyre 2 is fitted over the top of the tail portion 12,
so that when the tyre 2 is inflated, the air pressure in the tyre pushes the wall
of the tyre 2 against the tail portion 12, trapping it against the wheel 3. Ridges
15 on the side of the tail portion 12 facing the tyre 2 increase the frictional
engagement of the tail portion 12 with the tyre 2.
Figure 1 also
shows a centre line 16 extending axially outwards from a point equidistant from
the rim 4 and the closest part of the tyre 2 to the rim. It can be seen from
Figure 1 that the head portion 11 extends
further radially inwards, over the rim 4, than it extends outwards over the tyre
2. In other words, distance 17 is greater than distance 18. As discussed above,
this provides greater protection for the rim than otherwise and reduces the risk
that an impact on the head portion from the outer side - the tyre side - of the
protector 10 rips the protector at the junction between the head portion 11 and
the tail portion 12.
Accordingly, in the case of the wheel scraping an object
- such as if it were driven into a kerb - it is most likely that the initial impact
will be on the outer side 19 of the head portion; the impacting object (e.g. the
kerb) will move in a generally radially inwards direction. As this impact surface
slopes axially outwards, it acts to deflect gentler impacts outwards. In any case,
the rim protector will cover the rim 4 of the wheel 3, so as to protect it against
abrasion from and impact by the incident object.
That distance 17 is greater than distance 18 provides greater
protection for the rim than otherwise and reduces the risk that an impact on the
head portion from the outer side - the tyre side - of the protector 10 rips the
protector at the junction between the head portion 11 and the tail portion 12.
A second embodiment of the invention is depicted in
Figures 3 to 5 of the accompanying
drawings. This embodiment functions in a similar way to that of the first embodiment
and corresponding features have been given corresponding reference indicia, raised
by 20. Where a feature is not discussed below, it functions as for the first embodiment.
The main difference between this second embodiment and
the first embodiment is the shape of the head portion. Whereas the head portion
11 of the first embodiment was generally square in cross section, the head portion
31 of the second embodiment is more lopsided, with the larger side being on the
side that covers the rim 4. Thus, distance 37 is greater than distance 38 by more
than the difference between distances 17 and 18. The advantages of having more of
the head portion covering the rim are increased, whereas the disadvantages of having
more of the head portion on the side covering the tyre are reduced.
The tyre-engaging portion 42 of the head portion 31 is
curved, so that as the tyre is placed or inflated over the rim protector 30, the
tyre pushed the head portion 30, and specifically the rim-engaging portion 43 against
the rim 4. This helps ensure that the head portion 31 covers and so protects the
rim 4 in the case of an impact.
As with the first embodiment, the impact surface 39 is
sloped so as to deflect any impacts. In this case, the impacts are deflected onto
a rubbing surface 44, which lies parallel to the edge of the rim 4 and the general
direction of movement of the wheel (that is, radially). Any impacting objects will
then rub against the rubbing surface 44, instead of the rim 4. The rubbing surface
is effectively sacrificial, taking abrasion instead of the rim 4. As it is made
from a relatively soft material, it can be cleaned of scratches by scraping the
surface to reveal unscratched material below. In extreme cases, the protector may
need to be replaced; however this is still likely to be cheaper than replacing an
entire alloy wheel.
A third embodiment of the invention representing a modification
of the above two embodiments is shown in Figures
6 to 8 of the accompanying drawings. In this embodiment the reference numerals
used with respect to Figure 3 have been
increased by 100.
This embodiment works in the same way as that of
Figure 3, except that, at the point at
which the tail portion 132 joins the head portion 130, a ridge is provided on the
side adjacent the large portion of the head 131. This ridge 140 sits against the
rim 4 of the wheel once the rim protector 130 is installed in place. It means that,
one the rim protector 130 is installed, a gap 150 will be left between the head
portion 131 and the rim 4. This prevents the head portion 131 rubbing against the
Particularly if dirt becomes trapped between the head portion
and the rim, if it is not for the gap then there is the possibility that the head
portion will grind dirt against the rim, possibly abrading it and causing at least
cosmetic damage. However, the head portion 131 can still come into contact with
the rim 4 should it be required to protect the rim from impact; it is simply the
case that unless forced, the head portion 131 will tend to leave the gap 150 between
it and the rim 4.
Figure 8 depicts
how this embodiment with the ridge 140 can be used with the head portion shapes
of either of the first two embodiments.
A fourth embodiment of the invention is shown in
Figure 9 of the accompanying drawings.
This embodiment can extend any of the embodiments referred to above with respect
to Figures 1 to 8 of
the accompanying drawings.
In this embodiment, a rim protector 60 that can be according
to either of the above embodiments is provided in a circular shape. It provided
so as to be able to be cut to shape. In order to fit this embodiment to a wheel,
a first cut is made at point 61; the rim protector can be supplied to an end user
in this state, or the user can make the cut himself.
Graduations 62 are provided on the rim, with indices in
units of inches (2.54 cm) in diameter of the wheel to which the rim protector is
to be fitted. A user makes a second cut at the index graduation corresponding to
the size of his wheel; in the example shown in Figure
8 a cut at point 63 corresponds to a 13 inch (33 cm) diameter wheel. The
shorter section 64 remaining can then be discarded.
In order to fit the rim protector on the wheel, rather
than deflating the tyre and lifting its edge off the wheel, it has been appreciated
that with this ended version of the rim protector 60, the protector can simply be
hammered into place. With the tyre preferably fully deflated, but still on the wheel,
the user takes one end of the cut rim protector 60, and forces under the tyre
in situ. Conveniently, a rubber mallet may be used. The user then continues
around the tyre, forcing the length of the rim protector under the tyre until the
other end is adjacent to the original end.
A sealing compound can then be applied to fill any minor
gap that may be left, and to avoid the ingress of dirt and the like into the space.
Even if this were not done, it is unlikely that a small gap between ends would lead
to a significant loss of pressure in the tyre once inflated, as the bead of the
tyre will be pressing down on the rim in that region. The sealing compound can be
made to match the colour of the rim protector, which therefore gives a consistent
cosmetic appearance to the fitted rim protector.
Finally, the tyre can be fully reinflated.
The method by which the rim protector of this embodiment
can be installed is particularly convenient, because it does not require the tyre
to be removed. As such, it does not require any equipment more specialised than
a rubber mallet, whereas to install the uncut versions described above is likely
to require specialised tyre-replacement machinery. As such, an end user is likely
to be able to install this embodiment himself, rather than having to take his car
to a tyre workshop.
The rim protector can be made any desired colour; as such,
it may represent a possible customisation of the appearance of the vehicle's wheels
to an image-conscious vehicle owner.
Whilst the embodiments have been described with reference
to car alloy wheels, it is appreciated that invention has applications to any vehicle
wheel where it is desired to protect particularly the rim from impact and abrasion