RUNFLAT SAFETY BAND INCORPORATING WIRELESS DEVICE

The present invention relates to wheel well fillers or runflat safety bands and more particularly to such bands which incorporate a wireless device for remotely confirming the presence of the band on a wheel.

A wheel well filler or runflat safety band is a type of run flat system that can be retro fitted to a standard wheel and which operates to prevent the tyre bead from dropping into the wheel well when the tyre pressure decreases, either gradually due to a simple puncture or suddenly due to a blowout. Were the bead to drop into the wheel well, the tyre could work itself off the wheel. The runflat safety band is engaged into the well of the wheel, allowing the tyre bead to move across the wheel when the pressure within the tyre drops, but preventing the beads from falling into the wheel well and thereby locking the tyre onto the wheel and ensuring that there is always rubber between the wheel rim and the road surface or ground. Thus, steering, braking and cornering control are better maintained and the risk of accident due to tyre deflation greatly reduced. The system enables the driver to continue driving after deflation for a short period to a safe place where the wheel can be changed. The distance achieved before the tyre breaks up depends on the speed, on the amount of cornering and on surface conditions. There are different designs of band made from metal, or plastic, or a combination of the two, but all are basically composed of a ring, in one or more parts, whose width is equal to the width of the wheel well and which has dimples or inserts which rest on the bottom of the wheel well to space the band radially outwardly from the bottom of the well.

However, since the runflat safety band is mounted inside the wheel well, it is completely concealed within the wheel once the tyre is fitted, and hence it is not possible from an external inspection to check whether the band is fitted to the wheel or not, for example after replacement of the tyre. With a number of countries proposing regulations requiring the fitment of runflat safety bands to certain categories of vehicles, there is a concern that the authorities will not have a ready means of checking that the runflat safety bands have been fitted.

According to the present invention there is provided a wheel well filler or runflat safety band having a wireless device attached thereto that is remotely interrogatable in order to confirm the presence of the filler on the wheel.

A runflat safety band well filler according to the invention has the advantage that the presence of the runflat safety band can easily and reliably be verified via a simple external check, thereby avoiding the possibility of the runflat safety band being left off the wheel.

The wireless device is preferably a wireless sensor such as a SAW sensor, and may be fitted within a pressed safety band spacer dimple, fitted to a bracket provided on the safety band, or fitted to the underside of the sensor band. A suitable antenna will be provided on the sensor which may extend radially into the tyre cavity.

In a particularly preferred embodiment, the wireless sensor is a pressure and temperature sensor which provides remote indication of the pressure and temperature within the tyre, being interrogated to confirm the presence of the runflat safety band on the wheel, the ability to confirm that the tyre is running on the runflat band following tyre deflation and, because of temperature measurement, indicating that the tyre is overheating and likely to break up prematurely whilst running on the runflat band.

In order that the invention may be well understood, there will now be described some embodiments thereof, given by way of example, reference being made to the accompanying drawings, in which:

Figure IA is a perspective view of a conventional runflat safety band;

Figure IB is a perspective view of a wheel/tyre assembly showing how the tyre can skew on the wheel upon deflation;

Figure 1C is a sectional view through a tyre with the runflat safety band of Figure IA fitted; and

Figures 2 to 4 are show illustrative views of three embodiments of wireless sensor incorporated into a runflat safety band in accordance with the invention.

Referring to Figure IA, there is shown a ranflat safety band 1 which is generally known in the art, for fixing into the well of a wheel in order to prevent skewing of the tyre upon deflation during use. As shown in Figure IB, upon loss of pressure within the tyre 2, the bead 3 can slide across the inner surface of the wheel 4 and drop into the wheel well 5. This further reduces the tension holing the other bead on the rim, allowing the tyre to further skew, which results in a severe loss of control to the driver of the vehicle.

The runflat safety band 1 is fitted to the wheel so as to engage in the wheel well as shown in Figure 1C. The band 1 has inwardly extending studs 6 which engage against the radially inner surface of the well 5 so that the band projects out to the main inner surface 8 of the wheel, thereby preventing the tyre bead 3 from sliding across the wheel.

Referring now to Figure 2, there is shown a runflat safety band 10 according to a first aspect of the invention having a wirelessly interrogatable sensor 11 attached thereto by means of which the presence of absence of the band 10 from the wheel can be ascertained. The sensor 11 is mounted in a housing 12 which is attached to the radially inner surface of the band 10 between a neighbouring pair of studs 16. The thickness of the sensor and housing together is less than the height of the studs 16 so that the sensor does not rest against the base of the wheel well 5. An antenna 13 extends radially outwardly from the sensor housing 12, through the band 10 and into the aperture defined between the wheel and the tyre.

In an alternative arrangement shown in Figure 3, the sensor 21 and housing 22 are mounted within one of the studs 26 of the runflat safety band 20, an antenna 23 again extending radially outwardly from the sensor, through the band 20 and into the tyre cavity.

Figure 4 shows a third embodiment in which the sensor 31 and housing 32 are mounted in a bracket 37 which is again attached to the inner surface of the band 30, with an antenna extending radially outwardly through the band 30.

The sensor should be mounted on the inner surface of the band so that it is protected by the band against damage. Furthermore, other antenna configurations are possible, including electrically coupling the sensor to the band itself such that the band acts as the antenna.

The sensor is programmed to emit a response when interrogated in a manner well known to the person skilled in the art, which response signal is detected as confirmation of the presence of the band on the wheel. Advantageously, the sensor is a SAW sensor which is in fluid communication with the air in the tyre such that it also measures operating parameters of the tyre such as temperature, pressure and the like. The sensor may then be configured for separate interrogation depending on whether the tyre pressure, temperature, running on the runflat band, driving too fast whilst running on the ranflat band or the like is required or simply confirmation of the presence of the band. Alternatively, however, the detection of a pressure signal from the sensor can be used to interpret that the sensor, and hence the band, is present.