TITLE: "Spoke wheel, particularly for a tubeless-type tyre, intended to be mounted on a vehicle, particularly on a motor vehicle or a motorcycle"

The present invention relates to a spoke wheel, in particular for a tubeless-type tyre, intended to be mounted on a vehicle, particularly on a motor vehicle or a motorcycle.

More specifically, the present invention relates to a spoke wheel according to the preamble of the annexed claim 1.

An object of the present invention is to manufacture a spoke wheel of an improved type and the structure of which is particularly suitable to the use with a tubeless-type tyre.

This and other objects are achieved according to the present invention, due to a spoke wheel of the type specified above, and having the characteristics defined in the characterizing part of claim 1.

Further characteristics and advantages of the present invention will become clear from the following detailed description, given purely by way of non-limiting example, with reference to the annexed drawings, in which:

Fig. 1 is a cutaway perspective view, partially showing an exemplary embodiment of a spoke wheel according to the present invention;

Fig. 2 is a sectional partial view taken on an axial plane of the spoke wheel shown in Fig. 1;

Fig. 3 is a sectional view of a portion of the rim of the spoke wheel shown in the preceding Figures;

Fig. 3a is an enlarged view of the portion of the rim visible in Fig. 3 and obtained according to the line IHa-IIIa;

Fig. 4 is a view of one spoke of the spoke wheel shown in the preceding Figures;

Fig. 5 is a top perspective view of a washer of the spoke wheel shown in the pre ^¬ ceding Figures;

Fig. 5a is a sectional view of the washer shown in Fig. 5;

Fig. 6 is a sectional view of a hub of the spoke wheel shown in the preceding Figures; and

Fig. 7 is a sectional view of implementation details of the assembling between rim and spoke of the spoke wheel shown in the preceding Figures.

With reference in particular to Figures 1 and 2, an exemplary embodiment of a spoke wheel according to the present invention is generally indicated with 10.

In a per se known manner, the spoke wheel 10 includes a rim 12, a hub 14, which are mutually connected through a plurality of spokes 16. The spoke wheel 10 rotational axis is indicated with the line X-X visible in Figs. 1 and 2. As it shall be explained in the following of the present description, the spoke wheel 10 is intended to be mounted on a vehicle, particularly a motorcycle or a motor vehicle, and it is particularly suitable to the use in combination with tubeless-type tyres.

With reference still to Figures 1 and 2, the rim 12 has a plurality, or ring, of through-holes 18 located peripherally and through which the axially outer first ends 16a of the spokes 16 are connected. In the shown embodiment, such rim 12 defines a substantially channel- shaped cylindrical surface having a radially innermost bottom portion 12a, and a pair of flanks 12b radially projecting outwardly of the rim 12. The ring of through-holes 18 is lo- cated at the bottom portion 12a of the rim 12. Furthermore, a valve assembly 19 is applied in a per se known manner through the rim 12, intended to allow the inflating of the tube- less tyre when this is mounted on the wheel 10.

The hub 14 has a plurality of openings 20 obtained on the outer cylindrical surface 14a, which are coupled to the axially inner second ends 16b of the spokes 16. The openings 20 have respective inner threads 22 (see also Fig. 6) which engage with corresponding outer threads 24 (see Fig. 4) provided by the spokes 16 second ends 16b.

With reference in particular to Figs. 3 and 3 a, the rim 12 of the exemplary embodiment of the spoke wheel 10 shown in Figs. 1 and 2 will be now described in more detail.

In such embodiment, the through-holes 18 have a substantially radially oriented axis, and have an inwardly decreasing diameter. More particularly, each of the through-holes 18 has, respectively, an axially outer initial length 26 having a major diameter and connecting through a first tapering 28 to a median length 30 having an intermediate diameter. In turn, the median length 30 connects through a second tapering 32 to a final length 34 of the axially inner hole having a minimum diameter. The first tapering 28 and the second tapering 32 define cavity segments of a substantially frusto-conical shape, the function of which will be explained in the following of the present invention.

With reference in particular to Fig. 4, one of the spokes 16 of the exemplary embodiment of the spoke wheel 10 shown in Figs. 1 and 2 will be now described in more detail.

In such embodiment, each of the spokes 16 has an enlarged head 36 at the first end 16a, which has a cross section of a substantially hexagonal shape. The enlarged head 36 proceeds through a connecting portion 38 thereof, which tapers and ends, with a fillet, in an elongated shaft 40 of cylindrical circular shape extending mainly in the axial direction, and ending in a portion bearing the outer thread 24. The connecting portion 38 defines a sub- stantially frusto-conical length, the function of which will be explained in the following of the present description. Furthermore, in a per se known manner, the enlarged head 36 has a notch suitable to receive a screwdriver, or the cross section thereof is adapted to be received in a spoke wrench.

With reference in particular to Figs. 5 and 5a, one of the washers 42 adapted to be used in the assembling of the spokes 16 to the rim 12 in the exemplary embodiment of the spoke wheel 10 shown in Figs. 1 and 2 will be now described.

In such embodiment, the washer 42 has a substantially shaped-ring conformation surrounding a through central opening. The central opening has a first portion 44 having a tapering shape inwardly of the washer 42, and terminating in a second portion 46 having a circular cylindrical shape with a minimum diameter. Therefore, the first portion 44 defines a substantially frusto-conical cavity length. Furthermore, in the region in which the first portion is located, the washer 42 has an annular base 48 tapering outwardly of the washer 42. Therefore, the annular base 48 defines a substantially frusto-conical surface. In the assembling

With reference in particular to Fig. 7, details relative to the mounted condition of one of the spokes 16 on the rim 12 in the exemplary embodiment of the spoke wheel 10 shown in Figs. 1 and 2 are illustrated.

In such embodiment, it shall be noted that, in the assembled condition, each spoke 16 is fluid-tight connected with the rim 12 through the corresponding through-hole 18.

Suitably, a first sealing member and - preferably - a second, and - optionally - a third sealing members located around corresponding spoke 16 are interposed between each of the spokes 16 and the associated through-hole 18. Advantageously, each sealing member is an O-ring 50. Such O-rings 50 are stacked one on the other and located around the corre ^¬ sponding spoke 16.

Preferably, the plurality of O-rings 50 axially rests against the rim 12 at an abutting portion obtained in the corresponding through-hole 18. In the illustrated embodiment, the abutting portion is given by the inner surface of the second tapering 32 of the through-hole 18.

Preferably, each of the washers 42 is axially located between the corresponding enlarged head 36 of each spokes 16 and the O-rings 50 stacked one on the other.

Advantageously, each of the washers 42 is axially locked between the corresponding enlarged head 36 of each of the spokes 16 and a shoulder portion obtained in the corresponding through-hole 18. In the illustrated embodiment, the shoulder portion is given by the first tapering 28 of the through-hole 18. As it is visible in Fig. 7, the washers 42 abut against the respective stack of mutually overlapping O-rings 50.

Preferably, each of the washers 42 defines a respective second rest surface which is supported by the shoulder portion 28 of the corresponding through-hole 18, and converging towards the inside of the rim 12. In the illustrated embodiment, such first rest surface is defined by the first portion 44 of the through opening of the washer 42 supporting the head 36 connecting portion 38. The shape of the first rest surface allows some tolerance in the spoke 16 slope relative to the axis of the respective hole 18, so as to facilitate the assembling of the shaft 40 in the respective opening 20 of the hub 14.

Advantageously, each of the washers 42 defines a respective second rest surface which is supported by the shoulder portion which is given by the first tapering 28 of the correspond- ing through-hole 18, and converging towards the inside of the rim 12. In the illustrated embodiment, such second rest surface is defined by annular base 48 of the washer 42. The shape of the second rest surface reduces the risk of deformation of the washer 42 during the functioning of the spoke wheel 10.

Preferably, the first rest surface and the second rest surface are substantially parallel.

It shall be noted that the first length 26 of the hole 18 has a higher diameter than the transversal extension of the first end 16a of the spoke 16, leaving an annular ring which is sufficient to the insertion of the suitable spoke wrench.

According to the illustrated embodiment of the present invention, the head 36 and the connecting portion 38 thereof form a single head portion, manufactured as a single piece with the spoke 16, and integral part of the latter. According to a variant embodiment (not illustrated) of the present invention, the head portion formed by the head 36 and the connecting portion 38 thereof is replaced by an internally threaded nipple (not shown) which couples to the spoke 16 upper end 16a due to a complementary outer thread (not illustrated). In such variant embodiment, the nipple portion closer to the spoke 16 has the same configuration, and serves the same function of the head portion described for the embodiment illustrated in Figs. 1 to 7.

It will be appreciated that, the principle of the invention being understood, the embodiments and the implementation details will be able to be widely changed compared to what has been described and illustrated by way of non-limiting example only, without thereby departing from the scope of the invention as defined by the annexed claims.