阅读说明：本技术 辐条帽的头部与轮圈的桥接部之间的邻接接口和辐条自行车车轮 (Interface between the head of a spoke cap and a bridge of a rim and spoke bicycle wheel ) 是由 马里奥·梅焦兰 于 2020-11-25 设计创作，主要内容包括：辐条帽的头部与轮圈的桥接部之间的邻接接口和辐条自行车车轮。该自行车车轮包括轮圈、轮毂和连接两者的辐条,其中辐条通过辐条帽锚固至轮圈,该辐条帽具有杆部和头部,杆部插入在轮圈的桥接部中的孔中并且面朝轮毂,头部钩挂到桥接部。一种在所述头部与所述桥接部之间的邻接接口包括：-第一垫圈,其具有径向内第一面和径向外第二面,-第二垫圈,其具有径向内第一面和径向外第二面。垫圈的面成形为用以：在辐条到轮圈的固定操作的初始步骤期间,垫圈的面允许垫圈进行调整移动,以及反之,在辐条到轮圈的后续固定步骤期间,垫圈的面防止垫圈进行任何调整移动,在该后续固定步骤中,辐条帽受到通过辐条施加到该辐条帽的张力。(An abutment interface between the head of the spoke cap and the bridge portion of the rim and a spoke bicycle wheel. The bicycle wheel comprises a rim, a hub and spokes connecting the two, wherein the spokes are anchored to the rim by spoke caps having a stem inserted in a hole in a bridge of the rim and facing towards the hub, and a head hooked to the bridge. An abutment interface between the head and the bridge comprising: -a first washer having a radially inner first face and a radially outer second face, -a second washer having a radially inner first face and a radially outer second face. The face of the gasket is shaped to: the face of the washer allows the adjustment movement of the washer during the initial step of the spoke-to-rim fixing operation and, conversely, prevents any adjustment movement of the washer during the subsequent spoke-to-rim fixing step in which the spoke caps are subjected to the tension applied to them by the spokes.)

1. An abutment interface between a head portion (22) of a spoke cap (20) for securing a spoke (13) and a bridge portion (16) of a rim (11) of a bicycle wheel (10), the abutment interface comprising:

-a first washer (31; 131), the first washer (31; 131) having a radially inner first face (32; 132) and a radially outer second face (33; 133), the radially inner first face (32; 132) being intended to abut on the bridge (16),

-a second washer (41), said second washer (41) having a radially inner first face (42) and a radially outer second face (43), said radially inner first face (42) abutting on the second face (33; 133) of said first washer (31; 131), said radially outer second face (43) being intended to abut on the head (22) of said spoke cap (20),

wherein the face (32, 33, 42, 43; 132, 133) of the gasket (31, 41; 131) is shaped so as to: the faces (32, 33, 42, 43; 132, 133) of the washers (31, 41; 131) allow an adjustment movement of the washers (31, 41; 131) with respect to each other and with respect to the spoke cap (20) during an initial step of the fixing operation of the spoke (13) to the rim (11) and, conversely, the faces (32, 33, 42, 43; 132, 133) of the washers (31, 41; 131) prevent any adjustment movement of the washers (31, 41; 131) with respect to each other and with respect to the spoke cap (20) during a subsequent fixing step of the spoke (13) to the rim (11) in which the spoke cap (20) will be subjected to the tension applied to the spoke cap (20) by the spoke (13).

2. Abutment interface according to claim 1, wherein the abutment between the second face (33; 133) of the first gasket (31; 131) and the first face (42) of the second gasket (41) occurs along a first abutment trajectory (45) and the abutment between the second face (43) of the second gasket (41) and the head (22) of the spoke cap (20) occurs along a second abutment trajectory (46), wherein the first and/or the second abutment trajectory have an extension of less than 15%, preferably less than 10% and less than 15%, preferably less than 10%, of the area of the first face (42) of the second gasket (41), respectively.

3. The adjacency interface according to claim 2, wherein the first adjacency and/or second adjacency is a line (47, 44).

4. The interface according to claim 3, wherein the first face (42) of the second gasket (41) is delimited by a first inner perimeter (44) and a first outer perimeter (45), and wherein the second face (43) of the second gasket (41) is delimited by a second inner perimeter (46) and a second outer perimeter (47), wherein the first abutment trajectory coincides with the first outer perimeter (45) and the second abutment trajectory coincides with the second inner perimeter (46).

5. The interface according to claim 1, wherein the first washer (31; 131) has an opening (39), the width of the opening (39) being such as to allow the head (22) of the spoke cap (20) to pass through in the absence of the second washer (41).

6. The interface according to claim 1, wherein said first face (42) and said second face (43) of said second gasket (41) are conical or spherical.

7. The abutment interface according to claim 6, wherein the first face (42) of the second gasket (41) is tapered.

8. The abutment interface according to claim 6, wherein the second face (43) of the second gasket (41) is tapered.

9. The interface according to claim 6, wherein the second face (133) of the first washer (131) is spherical or toric.

10. The interface of claim 1, wherein the second gasket (41) is conical, having an apex facing towards the first gasket (31; 131), and the angle at said apex is between 70 ° and 120 °, preferably between 85 ° and 105 °, more preferably equal to about 95 °.

11. Bicycle wheel comprising a rim (11), the rim (11) being connected to a hub (12) by a plurality of spokes (13), wherein at least one of the spokes (13) is anchored to the rim (11) by a spoke cap (20), the spoke cap (20) having a stem (21) and an enlarged head (22), the stem (21) being inserted into a hole (17) in a bridge (16) of the rim (11) and facing towards the hub (12), the enlarged head (22) being hooked to the bridge (16), the bicycle wheel comprising an abutment interface (30; 130) between the head (22) of the spoke cap (20) and the bridge (16) of the rim (11), characterized in that the abutment interface (30; 130) comprises:

-a first washer (31; 131), the first washer (31; 131) having a radially inner first face (32; 132) and a radially outer second face (33; 133), the radially inner first face (32; 132) abutting on the bridge (16),

-a second washer (41), said second washer (41) having a radially inner first face (42) and a radially outer second face (43), said radially inner first face (42) abutting on said second face (33) of said first washer (31), said radially outer second face (43) abutting on said head (22) of said spoke cap (20),

wherein the face (32, 33, 42, 43; 132, 133) of the gasket (31, 41; 131) is shaped so as to: the faces (32, 33, 42, 43; 132, 133) of the washers (31, 41; 131) allow an adjustment movement of the washers (31, 41; 131) with respect to each other and with respect to the spoke cap (20) during an initial step of the fixing operation of the spoke (13) to the rim (11), and vice versa the faces (32, 33, 42, 43; 132, 133) of the washers (31, 41; 131) prevent any adjustment movement of the washers (31, 41; 131) with respect to each other and with respect to the spoke cap (20) during a subsequent fixing step of the spoke (13) to the rim (11) in which the spoke cap (20) is subjected to a tension applied to the spoke cap (20) by the spoke (13).

12. The bicycle wheel according to claim 11, wherein said first washer (31; 131) has an opening (39), the width of said opening (39) being such as to allow the head (22) of the spoke cap (20) to pass through in the absence of said second washer.

13. The bicycle wheel according to claim 11, wherein the head (22) of the spoke cap (20) has a spherical surface facing towards the second face (43) of the second washer (41).

14. Bicycle wheel according to claim 11, wherein said at least one spoke (13) has an orientation according to a non-radial direction (Y) with respect to an axis of rotation (X) of the wheel.

15. The bicycle wheel according to claim 11, wherein the bridging portion (16) of the rim (11) is flat in an axial direction of the wheel.

Technical Field

The present invention relates to spoke bicycle wheels, and in particular to the securing of spokes to a rim by means of spoke caps.

Background

Throughout the present description and claims, unless otherwise indicated, spatial indications will be given with reference to the axis of rotation of the bicycle wheel, such as in particular radial, axial or circumferential directions.

As is known, in spoked bicycle wheels, each single spoke is fixed to the rim of the wheel by means of a respective spoke cap, which is a part having a stem provided with a thread (usually an internal thread) and a head projecting from the stem. In the bridging portion of the rim (or in the lower bridging portion of the rim, in the case where the rim has two or more bridging portions), the rim is provided with a plurality of holes. The stem of the spoke cap is inserted into the respective hole from the radially outer direction, while the projecting head remains on the outside and is hooked to the bridge. Thus, the stem of the spoke cap is screwed to the end of the spoke. In this way, the spoke caps make it possible to hook the spokes to the rim and to allow tensioning of the spokes: in fact, by rotating the spoke cap, the spokes can be screwed in or out with respect to the stem. Generally, an abutment washer is arranged between the spoke caps and the bridge to improve the contact, in particular when the material of the rim (for example, aluminium or composite material) is very weak and it can be damaged by the excessive pressure exerted by the spoke caps on a limited area.

During tensioning, the spoke caps should ideally be arranged in alignment with the spokes as a substantial extension thereof. This is generally true because the spokes are typically arranged in the wheel in a substantially radial direction.

However, the applicant has observed that if the spokes are not arranged in a radial direction, for example because the spokes are tangentially fastened to the flange of the hub of the wheel, the tensioning of the spoke-spoke cap pair may cause misalignment between the two due to unbalanced abutment of the spoke caps on the bridge. In fact, the natural abutment of the spoke cap (with or without washer) with the stem in the radial direction is perpendicular to the bridge (more precisely, perpendicular to the tangent of the bridge); however, if the spokes are not in the radial direction, the spoke caps fixed to the spokes are also not in the radial direction before tensioning is started; in this position, the stem of the spoke cap forms two different angles (viewed in the axial direction) with the tangential direction of the bridge, one angle being smaller than 90 ° and one angle being larger than 90 °. Continuing the tensioning, the head of the spoke cap will tend to press more on the bridge on one side than on the other, in particular on the side with an angle greater than 90 °, tending to bring the tensioned spoke cap back towards the radial position.

This deviation of the spoke caps from the spoke direction increases as the tension progresses and results in abnormal stress distributions on the spokes, on the spoke caps and on the bridge of the rim. In particular, the spoke caps are stressed not only in the radial direction, but also in the tangential direction; the spokes are subjected not only to traction forces but also to bending forces. The result of this abnormal stress distribution forces designers to somehow oversize these components to avoid yielding. But there is thus an increase in weight, which is particularly undesirable in high-performance bicycles, in particular racing bicycles.

It has been proposed to solve this drawback by shaping the head of the spoke cap and the end face of the washer on which said head abuts according to a spherical surface. However, even with this solution, misalignment between the spokes and the spoke caps cannot be avoided.

The problem underlying the present invention is to allow a coupling between spokes, spoke caps and bridge parts, wherein the alignment between spokes and spoke caps is maintained during tensioning and thus also in the finished wheel, even if the spokes are not arranged in a radial direction.

Disclosure of Invention

Accordingly, in a first aspect thereof, the invention relates to an abutment interface according to claim 1; in a second aspect thereof, the invention relates to a bicycle wheel according to claim 11. Preferred features of the abutment interface and the wheel are given in the dependent claims.

More specifically, with reference to the first aspect of the present invention, an abutment interface between a head of a spoke cap for fixing a spoke and a bridge of a rim of a bicycle wheel comprises:

a first washer having a radially inner first face for abutting on the bridge and a radially outer second face,

a second washer having a radially inner first face abutting on the second face of the first washer and a radially outer second face abutting on the head of the spoke cap,

wherein the face of the gasket is shaped to: the face of the washer allows an adjustment movement of the washers with respect to each other and with respect to the spoke cap during the initial step of the spoke-to-rim fixing operation and, vice versa, prevents any adjustment movement of the washers with respect to each other and with respect to the spoke cap during the subsequent step of spoke-to-rim fixing in which the spoke cap is subjected to the tension applied to it by the spoke.

In fact, it has been observed that, in order to obtain the desired result of alignment between the spokes and the spoke caps in the finished wheel (even when the spokes are in a non-radial direction in the wheel), two features of distinct distinction are important for the coupling between the spoke caps and the rim: firstly, at the start of the tensioning operation, the spoke caps are allowed to be arranged in the direction of the spokes; then, during tensioning, the spoke caps are prevented from moving relative to the rim such that in the finished wheel, the spoke caps are aligned with the spokes.

In a preferred embodiment of the invention, the two features described above are obtained by providing: the abutment between the second face of the first washer and the first face of the second washer occurs along a first abutment trajectory and the abutment between the second face of the second washer and the head of the spoke cap occurs along a second abutment trajectory, wherein the first abutment trajectory and/or the second abutment trajectory have an extension of less than 15%, preferably less than 10%, and less than 15%, preferably less than 10%, of the area of the first face of the second washer, respectively. The measurement of the extension of the abutting trajectory is intended to be performed before the tensioning of the spokes, since the tensioning naturally implies an increase of the extension of the abutting trajectory due to the deformability of the material. With the above values, at least one of the contact between the two washers and the contact between the second washer and the spoke cap occurs over a limited area that is much smaller than the area of the face of the second washer; this allows a large initial freedom of movement when no tension has been applied, and a subsequent substantial locking when the tension applied on these small areas causes high contact pressure and therefore high friction.

Preferably, both the first and second abutment tracks have a limited extension, so that the two aforementioned features (initial freedom of movement and prevention of movement under tension) occur separately between the two washers themselves and between the second washer and the spoke cap.

Due to this abutment, the spoke cap and the two washers can also freely assume a posture in a non-radial direction of the wheel, guided by the coupling of the spoke cap with the spoke, in an initial mounting step with zero or minimal tension. However, once the tension becomes greater, the abutment track with limited extension ensures that the higher pressures generated immediately between the washers and between the second washer and the spoke cap prevent any further mutual movement, but the natural tendency is to orient in the radial direction due to the applied tension. As the tension gradually increases (and thus the tendency of the spoke cap to move in a radial direction increases), the pressure at the abutment track becomes higher in order to prevent any movement.

Preferably, the first abutment track and/or the second abutment track are lines, i.e. they have a substantially zero width, which maximizes the contact pressure. Of course, this geometry refers to the initial condition prior to tensioning, and is lost as the applied tension increases due to material deformation.

Preferably, the first face of the second washer is defined by a first inner periphery and a first outer periphery, and the second face of the second washer is defined by a second inner periphery and a second outer periphery, such that the first abutment track coincides with the first outer periphery and the second abutment track coincides with the second inner periphery. In this way, the feature of an adjoining track with a minimum width is obtained in a constructively simple manner.

Preferably, the first and second faces of the second washer are tapered or spherical. The obtaining of these surfaces is relatively simple and ensures the desired result in terms of abutment.

Preferably, the first face of the second washer is tapered. Preferably, the second face of the second washer is tapered. Preferably, the second face of the first washer is spherical. These shape features, individually or preferably all together, facilitate the initial freedom of movement and prevent the occurrence of both states of movement under tension.

Preferably, the second washer is conical and the apex of the second washer faces towards the first washer and the angle at this apex is between 70 ° and 120 °, preferably between 85 ° and 105 °, more preferably equal to about 95 °. This shape promotes the aforementioned abutment condition.

With respect to a second aspect, the present invention relates to a bicycle wheel comprising a rim connected to a hub by a plurality of spokes, wherein at least one spoke is anchored to the rim by a spoke cap having a stem inserted in a hole in a bridge of the rim and facing towards the hub and an enlarged head hooked to the bridge, the bicycle wheel comprising an abutment interface between the head of the spoke cap and the bridge of the rim, characterized in that the abutment interface comprises:

a first washer having a radially inner first face and a radially outer second face, the radially inner first face abutting on the bridge,

a second washer having a radially inner first face abutting on the second face of the first washer and a radially outer second face abutting on the head of the spoke cap,

wherein the face of the gasket is shaped to: the faces of the washers allow an adjustment movement of the washers with respect to each other and with respect to the spoke cap during the initial operating step of fixing the spoke to the rim, and vice versa, prevent any adjustment movement of the washers with respect to each other and with respect to the spoke cap during the subsequent step of fixing the spoke to the rim, in which the spoke cap is subjected to the tension applied to it by the spoke.

Preferably, the first washer has an opening whose width will allow the head of the spoke cap to pass through in the absence of the second washer. This greater width of the opening of the first washer facilitates freedom of movement between the two washers at the start of tensioning of the spoke with the spoke cap, and thus alignment.

Preferably, the head of the spoke cap has a spherical surface facing the second face of the second washer. The spherical surface of the head of the spoke cap favours the abutment condition described above, making it easier to limit the extension of the second abutment trajectory. Preferably, the radius of the spherical surface of the head of the spoke cap is between 2mm and 4mm, more preferably equal to about 3 mm.

Preferably, the stem of the spoke cap is joined to the head of the spoke cap according to a joining angle comprised between 25 ° and 60 °, more preferably between 30 ° and 50 °. The angle is considered to be the angle formed by the axis of the stem of the spoke cap and the tangent plane of the head of the spoke cap in the point where the head of the spoke cap is joined to the stem of the spoke cap. The aforementioned values make it possible to obtain the desired abutment conditions, in particular in the case in which the second gasket has the above-mentioned conical feature.

Preferably, at least one of the spokes has an orientation according to a non-radial direction with respect to the axis of rotation of the wheel. In fact, it is the spokes with such non-radial inclinations that obtain the greatest benefit from the solution of the invention.

Preferably, the bridge portions of the rim are flat in the axial direction of the wheel. In this way, the construction of the rim is particularly simple; in particular, no special treatment is required to form the shaped mount for the head of the spoke cap. Furthermore, by means of the invention, a precise and balanced hooking of the head of the spoke cap is equally ensured, without misalignment between the spoke and the stem of the spoke cap during tensioning.

Drawings

Other features and advantages of the present invention will become more apparent from the following description of some preferred embodiments of the invention, which refers to the accompanying drawings. In these drawings:

figure 1 is a partial perspective view of a bicycle wheel according to the present invention;

fig. 2 is an enlarged cross-sectional view of a detail of the wheel of fig. 1 with an abutment interface according to a first embodiment of the invention, the enlarged cross-sectional view being taken according to a plane perpendicular to the wheel axis;

figure 3 is an enlarged sectional view of a detail of figure 2 taken along a plane containing the wheel axis;

figure 4 is an exploded view of the wheel of figure 1, highlighting the abutment interface of figures 2 and 3;

FIG. 5 is a further enlarged cross-sectional view of the abutment interface shown in FIG. 2;

fig. 6 is an enlarged cross-sectional view of a wheel with an abutment interface according to a second embodiment of the invention.

Detailed Description

The drawings illustrate a bicycle wheel 10, the bicycle wheel 10 including a rim 11, the rim 11 being connected to a hub 12 by spokes 13 under tension; x is used to indicate the axis of rotation of the wheel 10. The spokes 13 have a head 14 and a threaded end 15 opposite the head 14, the spokes 13 being fastened to the hub 12 by the head 14 and the spokes 13 being hooked with the threaded end 15 to the bridge 16 of the rim 11 by the spoke caps 20. The bridge 16 is flat in the axial direction, i.e. the bridge 16 extends on a cylindrical surface coaxial with the axis X.

Each spoke cap 20 comprises: a stem portion 21, the stem portion 21 extending along an axis Y; and a head portion 22, the head portion 22 protruding with respect to the shaft portion 21. The stem 21 of the spoke cap 20 is inserted into a hole 17 formed in the bridge 16 and projects from this hole 17 in a radial direction towards the axis X of the wheel 10, while the head 22 remains in a radially outer position with respect to the bridge 16. A threaded axial hole 23 is formed in the stem 21, the threaded axial hole 23 engaging the threaded end 15 of one of the spokes 13; thus, the spokes 13 coupled with the spoke caps 20 are aligned along the axis Y. The spoke cap 20 further comprises: a first manipulation part 24, the first manipulation part 24 being externally formed on the lever part 21 and having a non-circular cross-section (e.g., hexagonal); and a second manipulation portion 25, the second manipulation portion 25 being externally formed on the head portion 22 and having a non-circular cross-section (e.g., square); the two handling portions 24 and 25 make it possible to rotate the spoke cap 20 with a suitable wrench (not shown) so as to screw or unscrew the spoke cap 20 with respect to the spoke 13, thus obtaining a variation in the length of the spoke 13-spoke cap 20 pair and thus a variation in the tension of such spoke 13-spoke cap 20 pair in the rim 11. The use of the actuating portion 24 or the actuating portion 25 depends on the accessibility, i.e. on the shape of the rim 11. The head 22 of the spoke cap 20 has a spherical shape that is convex toward the stem 21.

In the illustrated wheel 10, some of the spokes 13 have a substantially radial orientation, while others have a significantly non-radial orientation; when seen in the axial direction of the wheel 10, the spokes 13 having a substantially radial orientation form substantially right angles with the bridge 16 (i.e. with the tangent T of the bridge 16), whereas the spokes 13 having a significantly non-radial orientation form acute and obtuse angles α, β with the bridge 16 (see fig. 2).

An abutment interface 30 is disposed between the head portion 22 and the bridge portion 16 of the spoke cap 20, the abutment interface 30 including a first annular washer 31 and a second annular washer 41. The first washer 31 is in contact with the bridge 16 and the second washer 41 is in contact with the spoke cap 20.

The first gasket 31 has: a radially inner first face 32, the radially inner first face 32 resting on the bridge 16; and a radially outer second face 33, the radially outer second face 33 resting against the second gasket 41. The first face 32 is substantially flat, while the second face 33 is concave and has a spherical shape. The first gasket 31 has a very wide opening 39 in the center: as will be clear below, the head 22 of the spoke cap 20 can easily pass through this opening 39 if the head 22 of the spoke cap 20 is not retained by the second washer 41.

The first gasket 41 has: a radially inner first face 42, the radially inner first face 42 being seated on the first washer 31; and a radially outer second face 43, the radially outer second face 43 resting against the spherical head 22 of the spoke cap 20. The faces 42 and 43 are both conical, with the apex facing towards the first washer 31, i.e. towards the axis X of the wheel 10. The angle at the vertex of the cones of these two faces 42 and 43 is between 70 ° and 120 °, preferably between 85 ° and 105 °; particularly and more preferably, such angle is about 95 °. It should be noted that in the figures, the angle at the apex is not graphically represented, so as not to complicate the figures with other lines.

First face 42 of second washer 41 is bounded by a first inner perimeter 44 and a first outer perimeter 45; second face 43 of second washer 41 is bounded by a second inner perimeter 46 and a second outer perimeter 47. The inner peripheries 44 and 46 are wide enough to allow the stem 21 of the spoke cap 20 to pass through, but not the head 22 of the spoke cap 20.

A first abutment track is defined between the second face 33 of the first gasket 31 and the first face 42 of the second gasket 41, which ideally coincides with the first outer periphery 45 of the first face 42 of the second gasket 41. A second abutment track is defined between the second face 43 of the second washer 41 and the head 22 of the spoke cap 20, which ideally coincides with a second inner circumference 46 of the second face 43 of the second washer 41. In fact, the aforesaid abutment tracks may comprise narrow bands around the respective circumferences 45 and 46, as long as they are really narrow, in particular so that the area of the abutment tracks does not exceed 15% (preferably 10%) of the area of the respective faces 42 and 43 of the second gasket 41. Of course, what has just been mentioned refers to the initial mounted state of the wheel 10, i.e. before a large tension is applied between the spokes 13 and the spoke caps 20; under the effect of tension-induced traction stresses, the adjoining tracks have a marked tendency to widen due to the deformability of the material.

In the construction of the wheel 10, the mounting of each spoke 13 (irrespective of the inclination of the spoke 13 with respect to the radial direction) is carried out by first fastening the spoke 13 with its head 14 to the hub 12. Thereafter, the spoke cap 20 is inserted with its stem 21 in the hole 17 of the bridge 16, thus into the abutment interface 30, i.e. into the two washers 31 and 32; the first washer 31 is placed with its first face 32 against the bridge 16 and the second washer 32 is placed with its first face 42 against the second face 33 of the first washer 31. It should be noted that the width of the opening 39 of the first washer 31 will not be as wide as the head 21 of the spoke cap 20 is held, and if the second washer 41 is not present, the head 21 of the spoke cap 20 will easily pass through the opening 39.

By rotating the spoke cap 20, the spoke cap 20 can thus be screwed to the threaded end 15 of the spoke 13 until contact is established at the abutment tracks 45 and 46. In this case, the freedom of movement ensured by the washers 31 and 41 allows to easily arrange the spoke cap 20 in the extension of the spoke 13, so that the assembly of spoke 13 and spoke cap 20 is perfectly aligned according to the axis Y, even if the assembly of spoke 13 and spoke cap 20 does not coincide with the radial direction of the wheel 10.

By further rotating the spoke caps 20, the spoke caps 20 are thereby gradually tensioned over the spokes 13 such that the spokes 13 and the spoke caps 20 apply a traction force between the rim 11 and the hub 12. Since the extension of the abutment tracks 45 and 46 is very limited, this tensioning quickly leads to high contact pressures between the components, in particular between the spoke cap 20 and the second washer 41 and between the second washer 41 and the first washer 31. This high pressure induced friction prevents any mutual movement of the washers 31, 41 and the spoke cap 20, ensuring that the alignment of the spoke cap 20 and the spoke 13 along the axis Y is maintained even if this axis Y is not radially oriented in the wheel 10. Thus, the spokes 13 are not subjected to bending stresses and the spoke caps 20 are not subjected to stresses in the tangential direction.

Fig. 6 shows a wheel 110 according to a second embodiment of the invention; elements of the wheel 110 that are identical to elements of the wheel 10 are denoted with the same reference numerals and are not described again, while corresponding, but in some way different, elements are denoted with reference numerals increased by 100 and are described by comparison with elements of the wheel 10.

In the wheel 110, the spoke cap 120 differs from the spoke cap 20 in that the head 122 of the spoke cap 120 has a conical shape instead of a spherical shape. The abutment interface 130 differs from the interface 30 in the shape of the second face of the first gasket. More precisely, the first face 132 of the first gasket 131 (similar to the face 32 of the gasket 31) is flat, while its second face 133 has a substantially toric shape (toroidal shape). On the other hand, the second gasket is substantially the same as the gasket 41.

Thus, as can be seen in fig. 6, the first abutment trajectory is defined substantially in the intermediate annular region of the first face 42 of the second gasket 41, while the second abutment trajectory is defined on the inner region of the second face 43 of the second gasket 41. This first abutting trajectory, although different from the first abutting trajectory of the interface 30, remains narrow (preferably with an area less than 15%, more preferably 10%, of the area of the first face 42 of the second gasket 41); on the other hand, the second contiguous track has a wide extension, but still less than 40%. For this reason, the abutment interface 130 is less suitable in case the inclination of the spokes with respect to the radial direction is very high.

Construction of the wheel 110 proceeds in the same manner as described for the wheel 10.

In the above-described state, in which the first abutment trajectory between the first washer and the second washer and/or the second abutment trajectory between the second washer and the spoke cap have a limited extension, this state can also be obtained with other combinations of shapes of the faces of the washers and of the spoke cap.

For example, one embodiment (not shown) may provide a spoke cap having a tapered head, a tapered second washer (having two tapered faces), and a first washer having a second face that is also tapered. In this case, contiguous trajectories with limited extension are obtained by choosing conical shapes with different angles at the vertices: for example, the angle at the apex of the tapered second washer is significantly greater than the angle at the apex of the spoke cap and the angle at the apex of the second face of the first washer.

Another embodiment (not shown) may be similar to the wheel 10, for example, with the only difference that the second face of the first washer is not spherical but conical or toric.

Another embodiment may be, for example, similar to the wheel 110, with the only difference that the second face of the first washer is not toric, but spherical, and the concave face faces the second washer.

For example, another embodiment may be similar to wheel 10 or similar to wheel 110, and have a conical spoke cap instead of a spherical spoke cap; in this case, the second washer (cone) has a different angle, in particular a greater angle, at the apex with respect to the spoke cap.

Other embodiments may, for example, require that one or the other of the faces of the second washer be spherical or toric.

Thus, in selecting the shape of the spoke cap, the shape of the two faces of the second washer and the shape of the second face of the first washer, there is a degree of freedom, as long as the dimensional values (angle at the apex of the conical surface, radius of curvature of the spherical surface or toric surface) are selected such that the first abutment trajectory between the first washer and the second washer and/or the second abutment trajectory between the second washer and the spoke cap can have a limited extension; advantages will become apparent if the extension is less than 40% without deviating from the indicated optimum.