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Patent Searching and Data


Title:
BICYCLE HUB
Document Type and Number:
WIPO Patent Application WO/2017/195124
Kind Code:
A1
Abstract:
A bicycle hub (1) is provided, which is suitable to constrain a disc (11) of a disc brake (10) to the bicycle and defines a longitudinal axis (1b); the hub (1) comprises an engagement block (5) suitable to engage with the disc (11) defining a rotational constraint between the hub (1) and the disc (11); and a translation mechanism (8) suitable to translate the engagement block (5) along the longitudinal axis (1a) defining a position of use in which it is engaged with the disc (11) and a release position in which it is disengaged from the disc (11).

Inventors:
SCARSELLI MATTEO (IT)
SCARSELLI STEFANO (IT)
Application Number:
PCT/IB2017/052717
Publication Date:
November 16, 2017
Filing Date:
May 10, 2017
Export Citation:
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Assignee:
SCARSELLI MATTEO (IT)
SCARSELLI STEFANO (IT)
TESSANDORI PAOLO (IT)
International Classes:
B62L1/00; B60B27/00; B60B27/02
Domestic Patent References:
WO2014084560A12014-06-05
Foreign References:
US20160039491A12016-02-11
Attorney, Agent or Firm:
LUNATI & MAZZONI SRL (Via Carlo Pisacane 36, Milano, IT)
Download PDF:
Claims:
CLAI M S

1. A bicycle hub (1 ) suitable to constrain a disc (1 1 ) of a disc brake (10) to a bicycle and defining a longitudinal axis (1 b); said hub (1 ) being characterised in that it comprises

- an engagement block (5) suitable to engage with said disc (1 1 ) defining a rotational constraint between said hub (1 ) and said disc (1 1 );

- a translation mechanism (8) suitable to translate said engagement block (5) along said longitudinal axis (1 a) defining a position of use, wherein said engagement block (5) is engaged with said disc (1 1 ) defining said rotational constraint, and a release position, wherein said engagement block (5) is disengaged from said disc (1 1 ) releasing said rotational constraint.

2. The bicycle hub (1 ) according to claim 1 , wherein said translation mechanism (8) comprises a radial expansion kinematic system (81 ) suitable to control the transition of said engagement block (5) from said position of use to said release position by varying its radial extension.

3. The bicycle hub (1 ) according to the preceding claim, wherein said radial expansion kinematic system (81 ) comprises an articulated system (81 1 ) suitable to vary its radial extension and a command screw (812) for controlling the radial extension of said articulated system (81 1 ).

4. The bicycle hub (1 ) according to one or more of the preceding claims, comprising a main body (4) suitable to be integrally constrained to a wheel (1 a) and defining an inner chamber (4a); and wherein said engagement block (5) is at least partially housed in said inner chamber (4a) and axially mobile with respect to said main body (4) so that in said position of use said engagement block (5) at least partially protrudes from said main body (4) and in said release position said engagement block (5) is entirely housed in said inner chamber (4a).

5. The bicycle hub (1 ) according to one or more of the preceding claims, comprising a support (2) suitable to constrain said disc (1 1 ) to a first arm (1 c) of a fork of said bicycle (1 1 ) enabling said disc (1 ) to rotate with respect to said support (2) and to said first arm (1 c) and preventing said disc (1 1 ) from axially sliding with respect to said support (2).

6. The bicycle hub (1 ) according to one or more of the preceding claims, wherein said bicycle comprises a sprocket set (1 e) and wherein said hub (1 ) comprises a support (3) designed to constrain said sprocket set (12) to a second arm (1 d) of said fork allowing said sprocket set (1 e) to rotate relative to the support (3) and to the second arm (1 d) and preventing said sprocket set (1 e) from axially sliding with respect to said support (3).

7. The bicycle hub (1 ) according to one or more of the preceding claims, comprising a coupling (6) suitable to slide along said longitudinal axis (1 a) defining an attachment position in which it is engaged with said sprocket set (1 e) forming a rotational constraint between said sprocket set (1 e) and said hub (1 ) and a detachment position in which it is spaced from said sprocket set (1 e) releasing said rotational constraint.

8. The bicycle hub (1 ) according to the preceding claim, wherein said coupling (6) is at least partially housed in said inner chamber (4a) and axially mobile with respect to said main body (4) so that in said attachment position said coupling (6) at least partially protrudes from said main body (4) and in said detachment position said coupling (6) is entirely housed in said inner chamber (4a).

9. The bicycle hub (1 ) according to one or more of the preceding claims, wherein said translation mechanism (8) comprises a return member (82) suitable to oppose the transition of said coupling (6) into said attachment position and of said engagement block (5) into said position of use.

10. The bicycle hub (1 ) according to one or more of the preceding claims, comprising a shaft (7) defining a seat (7a) for said radial expansion kinematic system (81 ).

Description:
DESCRI PTION

BICYCLE HUB

The present invention relates to a bicycle hub of the type specified in the preamble of the first claim.

In particular, the object of the present invention discloses a device which allows the disc of a disc brake to be constrained to a front or rear wheel of a bicycle, suitably a road racing bicycle. Preferably, the hub constrains the disc of a disc brake to a rear wheel of a road racing bicycle.

As is known, the disc brakes currently used on bicycles are of the mechanical or hydraulic type and comprise a disc, which is integral with the wheel and has two brake contact surfaces formed on the two faces of the disc in the vicinity of the circumferential perimeter.

The action on the disc is exerted by a clamp equipped with pads and suitable to press the latter against the disc.

The disc brakes also comprise control means such as a lever through which the cyclist actuates the clamp.

The clamp is constrained to the frame and in particular to the fork or to the rear frame of the bicycle.

The disc is equipped with an adapter ring comprising a notched hole and adapted to engage with a notched surface formed on the hub. It is then locked in this position with pins (usually 6), which engage threads on the hub.

The above-mentioned prior art has a few major drawbacks.

A first drawback lies in the fact that replacing a disc-equipped wheel requires time- consuming and complicated operations because of the need to perform complicated manoeuvres. In fact, as the wheel and the disc are integrally constrained to one another, it is necessary to simultaneously remove the wheel from the fork and the disc from the clamps while avoiding impacts with the pads, which could alter the braking capacity of the disc brake by modifying the position of the pads.

It should be noted that the distance between the disc and the pads is particularly reduced and usually is 0.5 mm.

To avoid this drawback some operators decide to space the pads thus increasing such interspace. However, this solution results in a greater complexity and slowness of replacement as the distance of the pads must again be adjusted with extreme precision in order to restore a braking efficiency level equal to that prior to the replacement of the wheel.

The importance of this disadvantage is pointed out by the fact that the presence of disc brakes on road racing bicycles is very limited due to these long wheel replacement times.

This aspect is further enhanced by the fact that the discs can be equipped with numerous types of adapters, each requiring its own instrumentation for assembly and disassembly. For this reason, a mechanic would have to carry a large number of components and tools during a race and, at each intervention, waste time to find the correct ones to be used.

It should be stressed that the discs, in the case of intense braking, such as downhill, or in the case of frequent braking, such as when in group, tend by their nature to heat up quickly, thus making wheel replacement even more complicated.

In fact, an overheated disc reaches very high temperatures, which, during wheel replacement, make it necessary to use gloves or other protection that, by hampering the manoeuvres, make the replacing of a wheel equipped with a disc brake even slower.

A further drawback lies in the fact that the disc, by being particularly thin, can define a blade, which, for example, during a fall can injure the cyclist.

In particular, it is emphasized that the dangerousness of the disc can be increased by the heating and/or rotation of the same disc.

In this context, the technical task underlying the present invention is to devise a bicycle hub which is capable of substantially obviating the above-mentioned drawbacks.

Within the scope of said technical task, a major object of the invention is to provide a hub which allows a disc break to be constrained to a wheel in a simple and quick way.

In particular, an important object of the invention is to obtain a hub which allows a wheel of a bicycle, preferably a racing bicycle, to be replaced quickly, while ensuring the same braking efficiency as prior to replacement.

The technical task and the specified objects are achieved by means of a bicycle hub as claimed in the appended claim 1 .

Preferred embodiments are set forth in the dependent claims.

The features and advantages of the invention will be apparent from the detailed description of a preferred embodiment of the invention, with reference to the accompanying drawings, in which:

Fig. 1 shows a bicycle hub according to the invention;

Fig. 2 shows a second view of the hub according to the invention;

Figs. 3a-3h show a possible assembly of the hub; and

Fig. 4 shows a detail of the hub according to the invention.

In the present document, the measures, values, shapes and geometric references (such as perpendicularity and parallelism), when associated with words like "about" or other similar terms such as "almost" or "substantially", are to be understood as unless measurement errors or inaccuracies due to production and/or manufacturing defects and, especially, unless a slight difference from the value, the measure, the shape, or the geometric reference with which it is associated. For example, these terms, if associated with a value, preferably indicate a difference not exceeding 10% of the value itself.

Furthermore, when used, terms such as "first", "second", "higher", "lower", "main" and "secondary" do not necessarily identify an order, a priority relationship or a relative position, but can simply be used to distinguish more clearly the different components from each other.

With reference to the aforementioned figures, the bicycle hub according to the invention, as a whole, is indicated by the numeral 1.

It is adapted to be used to constrain a disc 11 of a disc brake 10 to a front or rear wheel 1a of a bicycle, suitably a racing bicycle. Preferably, the hub 1 is suitable to constrain a disc 10 to a rear wheel 1 a of a road racing bicycle.

The disc brake 10 is known per se.

It can comprise a disc 1 1 and an adapter ring 12 integrally attachable to the disc 1 1 , for example by means of screws or bolts. Alternatively, the disc 1 1 and the ring 12 are made in one piece.

It defines a surface 12a for engaging the wheel 1 a, which is suitable to project over the hub 1 and to define a rotational constraint with the hub 1 as described below. The adapter ring 12 comprises a central opening 12b whose section is smaller than the engagement surface 12a.

The disc brake 10 may comprise a protective guard 13 for the disc 1 1 . The guard 13 has an additional central opening 13a whose section is substantially equal to the central opening 12b.

The hub 1 defines a longitudinal axis 1 b adapted to coincide with the rotation axis of the wheel 1 a.

The hub 1 may comprise a support 2 for the disc 1 1 and, if present, for the protective guard 13.

The support 2 is suitable to constrain the disc 1 1 to a first arm 1 c of a fork or rear frame of the bicycle, allowing the disc 1 1 to rotate around the longitudinal axis 1 b with respect to the support 2, which in operating conditions remains rigidly coupled to the frame and to the first arm 1 c and, preferably, preventing the disc 1 1 from axially sliding with respect to the support 2.

In this document, the term axial identifies a length, a direction, a force and/or a movement parallel to the longitudinal axis 1 b around which the wheel 1 a rotates, while the term radial identifies a length, a direction, a force and/or a movement perpendicular to the longitudinal axis 1 b and radial with respect to the same wheel 1 a.

The support 2 (Figs. 3a and 3b) comprises a hollow rod 21 suitable to fit into the central opening 12b and having a rim 21a adapted to abut with the disc 1 1 ; a first retainer 22 adapted to hold the disc 1 1 against the rim 21 a, locking its axial sliding; and a bearing 23, a brass or other element adapted to allow rotation between the disc 1 1 and the rod 21 .

The first retainer 21 may comprise a stop ring (e.g. Seeger), in a threaded coupling or other similar solution adapted to provide said locking of the axial sliding.

Therefore, the support 2 may comprise a second retainer 24 adapted to tighten and then lock the first arm 1 c against the first retainer 22. Similarly to the first retainer 21 , the second retainer 24 may comprise a stop ring (e.g. Seeger), in a threaded coupling or other similar solution adapted to provide said locking of the first arm 1 c against the first retainer 22.

In some cases, a protective guard 13 is available between the first arm 1 c and the disc 1 1 . In this case, the rod 21 can be inserted in the central opening 13a, and the support 2 may comprise a third retainer 25 suitable to tighten the guard 13 against the first retainer 22, making it integral with the rod 21 .

The hub 1 may comprise a support 3 (Figs. 3c-3d) suitable to be integrally constrained to the second arm 1d of a fork of the bicycle.

In particular, the support 3 is adapted to be constrained to a sprocket set 1 e preventing the sprocket set 1 e from sliding with respect to a second arm 1 d of the fork, allowing the sprocket set 1 e to rotate around the axis 1 a with respect to the support 3 and the second arm 1 d, and preventing the set 1 e from axially sliding with respect to said support 3.

The sprocket set 1 e comprises one or more toothed wheels suitable to receive the motion produced, for example, by a muscular action and to transmit it to the wheel

1 a.

The support 3 may comprise a hollow bar 31 suitable to fit into a seat formed in the sprocket set 1 e and having an edge 31a suitable to abut with the sprocket set 1 e; a fastening member 32 adapted to hold the sprocket set 1 e against the edge 31 a, locking its axial sliding; and a bearing, a brass or other element adapted to allow rotation between the sprocket set 1 e and the support 3.

The bar 31 and the rod 21 may be cylindrical and have the same outer diameter. The fastening member 32 may comprise a stop ring (e.g. Seeger), in a threaded coupling or other similar solution adapted to provide said locking of the axial sliding of the sprocket set 1 e.

In order to provide the constraint to the second arm 1 d, the support 3 may comprise a fitting 33 suitable to tighten and then lock the second arm 1 d against the fastening member 32 or, in the absence of the sprocket set 1 e, against the edge 31 a.

The fitting 33 may comprise a stop ring (e.g. Seeger), in a threaded coupling or other similar solution adapted to provide said locking of the second arm 1 d.

The hub 1 may comprise a main body 4 (Fig. 4) suitable to be integrally constrained to the wheel 1 a and defining an inner chamber 4a extending predominantly along the longitudinal axis 1 b.

The hub 1 may comprise an engagement block 5 (Fig. 4) suitable to engage with the disc 1 1 , defining a rotational constraint between the hub 1 and the disc 1 1 , i.e. a constraint preventing at least a mutual rotation between the disc 1 1 and the hub 1 , and therefore between the wheel 1 a and the disc 1 1 .

The engagement block 5 may comprise a constraint surface 5a designed to engage with the engagement surface 12a, thus providing such a rotational constraint. This constraint surface 5a is then shaped complementarily to the engagement surface 12a.

The engagement block 5 is axially movable with respect to the main body 4 so as to define a position of use in which the engagement block 5 is engaged with the disc 1 1 , thus providing said rotational constraint, and a release position in which the engagement block 5 is spaced from the disc 1 1 , thus releasing the rotational constraint and allowing the removal of the disc 1 1 and/or of the wheel 1 a.

In particular, the engagement block 5 is at least partially housed in the inner chamber 4a and axially movable with respect to the main body 4 so that in the position of use the engagement block 5 at least partially protrudes from the main body 4, engaging the disc 1 1 , and in the release position the engagement block 5 is entirely housed in the inner chamber 4a.

In order to guide the axial sliding of the block 5, the main body 4 may comprise an axial track 41 suitably defining for the block 5 a first stop corresponding to the position of use and, in detail, a second stop corresponding to the release position. Said stops may be stop rings and/or abutment surfaces.

To allow transfer of motion between the disc 1 1 and the wheel 1 a, the engagement block 5 is rotationally constrained to the main body 4. This rotational constraint is obtainable with pins or contact surfaces between the block 5 and the body 4, which are complementarily shaped with respect to one another.

The engagement block 5 finally comprises a through hole 5b extending along the axis 1 b.

The hub 1 may comprise a coupling 6 (Fig. 4) suitable to define a rotational constraint with the sprocket set 1 e.

To this end, the sprocket set 1 e may comprise an attachment surface and the coupling 6 may comprise an engagement surface 6a adapted to engage with an attachment surface of the sprocket set 1 e, thus providing the rotational constraint.

The coupling 6 is axially movable with respect to the main body 4 so as to define an attachment position in which it is engaged with the sprocket set 1 e, thus providing the rotational constraint, and a detachment position in which it is spaced from the set 1 e, thus releasing the rotational constraint.

In particular, it is at least partially housed in the inner chamber 4a and axially movable with respect to the main body 4 so that in the attachment position it protrudes, at least partially, from the main body 4, engaging the sprocket set 1 e, and in the detachment position it is entirely housed in the chamber 4a. In order to guide the axial sliding of the coupling 6, the main body 4 may comprise an axial guide 42 suitably defining a first end-of-stroke position of the coupling 6 corresponding to the attachment position, and in particular a second end-of-stroke position of the coupling 6 corresponding to the detachment position.

Said end-of-stroke positions may be provided by means of a stop ring and/or an abutment surface.

To allow transfer of motion from the sprocket set 1 e to the wheel 1 a, the coupling 6 defines a rotational constraint with the main body 4, which can be provided, for example, by means of pins or complementarily shaped surfaces contacting the coupling 6 and the main body 4 to each other.

Lastly, the coupling 6 comprises a through cavity 6b extending along the axis 1 b.

Said through cavity 6b has a cross section smaller than the through hole 5b.

The hub 1 may comprise a shaft 7 (Fig. 3e) adapted to mutually engage the disc 1 1 , possibly the guard 13 and, if present, the sprocket set 1 e.

The shaft 7 is insertable and removable with respect to the inner chamber 4a, the rod 21 and, if present, the bar 31.

It extends along the longitudinal axis 1 b.

The shaft 7 comprises a first portion 71 adapted to fit into the disc 1 1 and the through hole 5b, and a second portion 72 defining an axial extension of the first portion 71 and suitably adapted to fit into the through cavity 6b and the support 3.

The first portion 71 and the second portion 72 are integral with one another, and in detail made in one piece.

The first portion 71 is adapted to axially lock the support 2 against the block 5. To this end, it defines a retaining surface 71a perpendicular to the longitudinal axis 1 b and adapted to hold the rod 21 between the engagement block 5 and the same retaining surface 71 a.

The first portion 71 has a larger section than the second portion 72, and in particular larger than that of the through cavity 6b so that the shaft 7 defines an abutment surface 73 adapted to place the coupling 6 in the attachment position as described below.

Finally, the shaft 7 and, in particular, the first portion 71 define a seat 7a extending along the axis 1 b.

The hub 1 may comprise a translation mechanism 8 (Fig. 3e and 4) adapted to axially translate the engagement block 5, thus defining the above-mentioned configuration of use and release configuration.

To this end, the mechanism 8 comprises a radial expansion kinematic system 81 suitable to control the transition of the block 5 from the position of use to the release position by varying its radial extension; and a return member 82 to put the block 5 back into the release position.

The radial expansion kinematic system 81 is adapted to define a maximum radial extension greater than the through hole 5b so as to contact the engagement block 5, pushing it axially. Said maximum radial extension is greater than the radial extension of the seat 7a, which therefore may comprise radial openings 7b through which the radial expansion kinematic system 81 can radially protrude from the seat 7a.

The radial expansion kinematic system 81 is extractable from the seat 7a, and is therefore adapted to define a minimum radial extension smaller than the radial extension of the seat 7a.

The radial expansion kinematic system 81 may comprise an articulated system 811 suitable to vary its radial extension; and a command screw 812 for controlling the radial extension of the articulated system 81 1 .

The articulated system 81 1 comprises at least a pair of rods 811 a hinged to each other and whose remaining ends identify a first end and a second end. In particular, the articulated system 81 1 comprises a plurality of pairs of rods 81 1 a substantially equally angularly spaced from one another.

In order for the radial extension of the articulated system 81 1 to be varied, the kinematic system 81 is adapted to provide, by exploiting the pair of rods 81 1 , a mechanism similar to the connecting rod-crank mechanism in which the first end is axially static, and therefore the respective rod is comparable to a crank, and the second end is axially movable, and therefore the respective rod is comparable to a connecting rod. Therefore, the kinematic system 81 may comprise an anchor 813 hinged to the first end of each pair of rods 81 1 a and adapted to be integrally constrained to the first portion 71 , thus making this end integral with the shaft 7; and a slider 814 which is hinged to the second end of each pair of rods 81 1 a and engaged with the command screw 812 so as to slide thereon, thereby dragging the second end associated therewith.

The slider 814 may be a nut or other similar element having a threaded hole, and the command screw 812 may be a screw and therefore be at least partially threaded, thus exhibiting at least one threaded portion for the engagement of the slider 814. The anchoring support 813 is identifiable as a cylinder defining a housing 813a in which the command screw 812 can rotate with respect to the same support 83. The anchoring support 813 is suitable to fit into the seat 7a. It is adapted to be integrally constrained to the first portion 71 , thus making the kinematic system 81 integral with the shaft 7. This constraint between the support 813 and the first portion 71 is of the resolvable type. The command screw 812 is almost entirely housed in the seat 7a, and in order to allow its practical implementation, it may comprise a lever 812a outside said seat. The return member 82 is suitable to work in opposition at least to the radial expansion kinematic system 81 , thus putting the engagement block 5 from the position of use back into the release position.

Moreover, the return member 82 is suitable to place the coupling 6 in the detachment position and, in particular, to oppose the transition of the coupling 6 into the attachment position.

In particular, the return member 82 is suitable to oppose the transition of the coupling 6 into the attachment position and of the engagement block 5 into the position of use.

The return member 82 may comprise one or more springs, preferably compression springs, subtended between the block 5 and the coupling 6, opposing their mutual spacing.

The method of assembling a bicycle hub, described above as regards structure, is as follows.

Before the assembly begins, the return member 82 puts the engagement block 5 and the coupling 6 into the respective release configurations, and precisely into mutual contact at the second stop and at the second end-of-stroke position.

Firstly, the method can comprise fastening the support 2 to the disc 1 1 and to the first arm 1 c (Figs. 3a-3b).

Performing this operation requires the operator to insert the rod 21 in the central opening 12b bringing the disc 1 1 in contact with the rim 21 a, and then block it axially with the first stop 22. Then, the rod 21 is inserted in the protective guard 13, which is then locked by the third stop 25. The constraint of the support 2 is completed by the second stop 24, which locks the rod 21 to the first arm 1 c.

The method can comprise fastening the support 3 to the second arm 1 d and, if present, to the sprocket set 1 e (Fig. 3c-3d).

This operation requires the bar 31 to be placed in the sprocket set 1 e which thus contacts the edge 31 a and is there axially locked by the fastening member 32. This operation is completed by using the fitting 33 to integrally constrain the bar 31 to the second arm 1 d.

The assembly method may now comprise inserting the radial expansion kinematic system 81 , which is arranged with the minimum radial extension in the seat 7a, and integrally constraining the radial expansion kinematic system 81 to the shaft 7. This step is shown in Fig. 3e.

At this point, the assembly method comprises arranging the main body 4 and therefore the wheel 1 a between the arms 1 b and 1 c, in particular between the support 2 and the support 3; and inserting it in the rod 21 and the bar 31 , and in the inner chamber 4a of the shaft 7 and of the kinematic system 81 housed therein (Fig. 3f) so as to bring the abutment surface 73 in contact with the coupling 6.

Then, the assembly method may provide axial locking of the disc 1 1 to the hub 1 (Fig. 3g) and, optionally, simultaneous rotational locking of the sprocket set 1 e to the wheel 1 a.

With this operation, the second portion 72 is screwed to the bar 31 , thereby causing a forward axial movement of the shaft 7.

This forward movement brings the retaining surface 71 a into contact with the rod 21 , which, together with the disc 1 1 , is thus axially locked.

In addition, the forward axial movement of the shaft 7 causes the abutment surface 73 to axially push the coupling 6 along the axial guide 42 until it reaches the attachment position in which it is rotationally constrained to the sprocket set 1 b (Fig. 3g).

It should be noted that this forward movement of the coupling 6 is done in opposition to the return member 82.

Then, the assembly method is completed by rotationally locking the disc 1 1 to the hub 1 (Fig. 3h).

The operator, by exerting a force on the lever 812a, rotates the command screw 812 causing axial translation of the slider 814.

The axial translation of the slider 814 causes axial translation of the one or more second ends hinged thereto, which then approach the one or more first ends rigidly coupled to the shaft 7, causing radial expansion of the pairs of rods 81 1 a, and therefore of the radial expansion kinematic system 81 .

This expansion causes the kinematic system 81 to contact the engagement block 5 and push it axially towards the disc 1 1 , causing engagement of the constraint surface 5a with the engagement surface 12a, and therefore rotational constraint between the disc 1 1 and the wheel 1 a.

The invention provides significant advantages.

In fact, an important advantage is that the hub 1 allows an extremely simple and fast assembly or replacement of the wheel 1 a.

In fact, the rotational release of the disc 1 1 is simply accomplished by bringing the engagement block 5 into the release position by acting on the command screw 812.

Moreover, the presence of the support 2 allows for leaving the disc 1 1 engaged with the wheel 1 a, and thus for only removing the wheel 1 a.

This simplicity of replacement is very evident in the case of replacement of the rear wheel 1 a where even the pinion 1 e remains attached to the fork and, therefore, only the wheel 1 a is removed.

Said simplicity of assembly/replacement also applies to the innovative shaft 7 which, by being easily removable, makes the aforesaid operations very simple.

It is also pointed out that the ability to replace the wheel 1 a without removing the disc 1 1 allows for preventing deterioration of the braking performance.

Furthermore, the translation mechanism 8, namely the radial expansion kinematic system 81 and the return member 82, as they are housed in the shaft 7, can be easily removed and then replaced without removing other components of the hub 1 and/or the disc 1 1 .

This aspect is further enhanced by the fact that the hub 1 allows the engagement block 5, coupling 6 and main body 4 ensemble to be independent of the disc 1 1 . Therefore, another advantage of the hub 1 lies in the fact that it is usable with any type of disc and any type of wheel.

For example, in fact, the possibility of translating the engagement block 5 allows for adjusting the axial position of the same engagement block 5, and therefore ensuring rotational constraint between the hub 1 and the disc 1 1 irrespective of the thickness of the disc 1 1 or of its axial position.

It is noted that, in a similar way, the possibility to axially translate the coupling 6 allows for adjusting the position of the same coupling 6 to the sprocket set 1 e, ensuring rotational constraint of the hub 1 to different sprocket sets 1 e.

Another important advantage is therefore that the adoption of the hub 1 allows for reducing the number of tools that, in any race, a mechanic must carry to assist all the cyclists of his/her own team.

A further advantage lies in the fact that the hub 1 , by allowing the guard 13 to be mounted easily, allows the disc 1 1 to be enclosed within the guard itself, preventing it from cutting/injuring the cyclist.

The invention is susceptible of variations falling within the scope of the inventive concept, as specified in the independent claims, and of the related technical equivalents. In this context, all details are replaceable by equivalent elements and any type of materials, shapes and dimensions may be present.

For example, in the case of a hub 1 attachable to a front wheel 1 a, the sprocket set 1 e can be replaced by a body comprising an attachment position similar to that provided on the sprocket set 1 e and hence engageable with the engagement surface 6a of the coupling 6.

This solution makes it possible to use the same hub 1 both for the front wheel 1 a and for the rear wheel 1 a, allowing a mechanic to use a hub 1 to replace any one of the hubs 1 of the front and rear wheels 1 a.

In addition, in order to control the variation of the radial extension of the articulated system 81 1 , the kinematic system 81 may comprise a spring suitable to control the transition of the coupling 6 between the detachment and attachment positions. Said spring can therefore control the motion of the movable end (for example the second one) of the rods 81 1 and precisely of the slider 814.

The spring can be adapted to work in opposition to the command screw 812.

In particular, the command screw 812 can control the transition of the coupling 6 from the detachment position to the attachment position in opposition to the spring, which then charges as it reaches the attachment position; the spring can control the transition of the coupling 6 from the attachment position to the detachment position by exploiting the energy accumulated whilst reaching the attachment position. The spring may be a compression spring suitable to contract, and thus charge during transition into the attachment position, and discharge by commanding the transition into the detachment position. For example, the spring can be inserted between the first and the second end of the articulated system 81 1 so as to contract as a function of the distance between the ends along the longitudinal axis 1 b.

Finally, it is pointed out that, at least in the case of the spring, the articulated system 81 1 can provide for both the first end and the second end movable along the longitudinal axis 1 b, and the spring acting, for example, on the second end, and the command screw on the first.