The present invention concerns a solid tyre developed for industrial and construction applications with enhanced reduction of whole body vibration exposure and improved comfort.

As is well known, tyres made of solid rubber, also called solid tyres, are often used in industrial and construction applications.

Resilient tyres are a known type of solid tyre which are structurally composed of a plurality of radially overlapping circular layers made of elastic material, said layers typically forming, from the centre of the tyre towards the periphery, at least one inner portion called base, and an outer portion called tread.

Resilient tyres are used on many types of construction machines, industrial vehicles, trucks and trailers. In particular, these tyres are widely used in machines for the movement of materials, for example loaders, since they are highly resistant to puncturing. See, for example, construction and industrial applications involving the management of metal waste, which is often sharp and would puncture an air- inflated tyre.

In order to withstand puncturing, the known resilient tyres are made of a compound of materials with high hardness, typically equal to 85±10 Sh A for the base (where Sh indicates the unit of measurement on the Shore scale for testing the hardness of elastomers) and equal to 70±5 Sh A for the tread.

However, industrial and construction machines, and in particular loaders, which use such hard tyres are uncomfortable for the driver-operator, as they are not provided with suspension. The springs provided below the driver's seat and the low elasticity of the tyres are the only form of suspension of the vehicle.

Epidemiological studies show that drivers and operators working in a sitting position in these machines are likely to develop backache (in the lower part of the spinal column) and sciatica. The frequent exposure to vibrations and repeated impact at sufficiently high levels for months or years can cause injury to the vertebrae and intervertebral discs. Therefore, the longer the duration and levels of exposure, the greater the likelihood of the driver-operator suffering from back pain. The object of the present invention is to provide a resilient tyre with shock absorbing properties such as to reduce, if not solve completely, the above- mentioned problems which affect the driver-operators.

According to the present invention, said object is achieved by means of a resilient tyre according to claim 1.

The characteristics and advantages of the present invention will become evident from the following detailed description of a practical embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, in which:

- figure 1 shows a perspective view of a resilient tyre according to the present invention;

- figure 2 shows a front view of the resilient tyre of Fig. 1 ;

- figure 3 shows a section view according to the line Ill-Ill of the resilient tyre of Fig. 2;

- figure 4 shows a detail of the section view of the resilient tyre of Fig. 3.

Referring to Fig. 1 , a resilient tyre according to the present invention is indicated overall by the reference number 1.

The resilient tyre 1 is designed to be used in construction and industrial applications on many types of vehicles such as, for example, vehicles for the movement of materials. In particular, these vehicles include loaders, which are machines used to handle material, such as construction or industrial waste of any type (for example metals), moving and loading said material onto lorries which then transport it to its final destination.

Structurally, referring to Fig. 4, the resilient tyre 1 comprises a plurality of circular layers made of radially overlapping elastic material, said layers forming, from the centre of the resilient tyre towards the periphery, an inner portion called base 2, an outer portion called tread 3 and two lateral surfaces 4 (or sides).

In particular, the base 2 is the portion of the tyre 1 which is mounted around the wheel rim, in turn made integral with the axle which rotates the wheel. Preferably, the base 2 has a hardness of 80±15 Sh A (where Sh indicates the unit of measurement on the Shore scale for testing the hardness of elastomers or elastomers in general). The tread 3, on the other hand, is the portion of the structure of the resilient tyre 1 which comes into contact with the ground on which the wheel rotates. The tread 3 can be smooth or provided with grooves, the number, shape and depth of which vary according to the intended use of the tyre.

Furthermore, the tyre comprises a plurality of shock-absorbing holes 7 made on at least one lateral surface of the resilient tyre 1 , said holes 7 being designed to act as suspension for the construction machine in order to limit, if not completely eliminate, the effects of the vibrations and repeated impact caused by the vehicle on the operator.

Preferably, the holes 7 are made in each of the two lateral surfaces 4 of the resilient tyre (Fig. 3, 4). Furthermore, the holes 7 have a depth that does not exceed the half-width of the tread 3.

In a first embodiment, the holes 7 made on a lateral surface 4 of the tyre are specular to those holes 7 made on the other lateral surface and are separated from each other by a portion of intermediate tyre 8 (Fig. 3, 4). In a further embodiment the holes 7 made on a lateral surface 4 are alternate with respect to those holes 7 made on the other lateral surface.

In particular, the holes 7 are equidistant from one another, arranged radially with respect to an axis X of rotation of the tyre, and also uniformly positioned along a circumference C with a radius smaller than that of the tyre.

As shown in Fig. 2, the holes 7 have a substantially elliptically shaped opening and substantially have the shape of an elliptical cylinder terminating in a conical end. However, also other shapes of the holes 7 can in turn perform a shock-absorbing function in a wholly equivalent manner. In a further embodiment, not shown in the figures, the resilient tyre can comprise holes 7 made on one single lateral surface 4, the depth of which completely crosses the width of the tread 3.

The tread 3 is made of a compound which has a hardness ranging from 45 to 65 Sh A, preferably from 50 to 60 Sh A, more preferably equal to 56±3 Sh A. As is evident, these hardness values are lower than the values used for the tread of the known resilient tyres (which have a hardness of 70±5 Sh A). Despite this, the resilient tyre 1 , according to the present invention, maintains optimal properties in terms of resistance to puncturing.

In the case of many vehicles, such as loaders, the particular hardness value of the tread 3 between 45 and 65 Sh A is such as to enable the tyre (and in particular the tread 3) to deform under the weight of the vehicle, deadening vibrations and impact which affect the driver-operator.

The effects of the resilient tyre according to the present invention are highlighted by the following test carried out in compliance with the UNI EN 13059:2008 standard concerning the safety of industrial trucks and test methods for measuring the vibrations.

In this test a test loader was used with the following characteristics:

The test route and conditions are established by the UNI EN 13059:2008 standard (section 5 of table 1 ). In particular, the test conditions establish that the loader passes through two obstacles (figures 2-3 of the Uni EN 13059:2008 standard) present along the route, having a height h = 15 mm and crossed at a speed of 10 km/h.

The test was carried out on two different sets of tyres:

- known resilient tyre (type 1 ),

- resilient tyre, according to the present invention, with solutions to improve operator comfort (type 2).

The test was repeated 5 times and the results of the test (calculated according to paragraph 8.3 of the UNI EN 13059:2008 standard) are shown in the following table:

Vertical acceleration on the Vertical acceleration on the

1 ^N operator's seat operator's seat

(Loader full) (Loader empty)

Type 1 1.39 m/s 1.42 m/s*

Type 2 1.07 m/s 1.10 m/s From the results shown in the table, it is evident that the acceleration on the operator's seat in the case of use of the resilient tyre of type 2 is 30% lower than with use of the known resilient tyre (type 1 ).

Due to the resilient tyre according to the present invention, and in particular the cooperation between the characteristics of appropriate hardness of the tread 3 and the shock-absorbing holes 7 made in correspondence of the side of the tyre, the effects of the vibrations and repeated impact on the operator are limited or completely eliminated.