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Field of the invention

The present invention regards foldable or collapsible wheels comprising a rim with rubberised sectors that can be configured, starting from an extended condition for forming the rim, in a collapsed condition for minimum overall dimension of the wheel.

State of the prior art

Collapsible wheels are described and illustrated for example in documents US-8371659, US-8833864, US- 2012/0032497, US-2014 / 0097666 and US-2015/0084398.

Foldable wheels thus made can advantageously be used, for example, for equipping foldable bicycles with the aim of reducing overall the dimensions thereof and facilitating transportation and putting it away when not being used.

The foldable wheel described in document US-

2015/0084398 corresponds to the pre-characterised part of claim 1: it comprises a double hub and spokes which pivotly connect each hub with the sectors of the rim. The spokes have a fixed length and the hubs can be displaced between an approached condition, corresponding to the extended condition of the sectors in which the rim is made, and a spaced condition in which the spokes extend substantially parallel to the wheel axis and the sectors of the rim are folded.

This prior art solution reveals several drawbacks: firstly, the wheel, even in the collapsed configuration, has a considerable radial overall dimension due to the fact that the folded sectors of the rim are arranged around the spokes according to two axially spaced circumferential groups distinct from each other. Secondly, the wheel is formed by a large number of components and a plurality of articulations between the components which, besides complicating the structure and the manufacturing, also imply a considerable weight and ensuing challenges not only when it comes to moving the wheel in collapsed condition but also during the use thereof in the extended condition for example with a bicycle, due to a difficult manoeuvrability. A further drawback of this prior art collapsible wheel regards the system for locking the sectors of the wheel by the spokes in the extended condition, revealing poor resistance to impacts and thus poorly reliable in use.

Document CN-103963557A describes a collapsible wheel comprising a rim with segments, foldable rods and a central shaft suitable to be folded and unfolded.

Summary of the invention

The object of the present invention is to overcome the aforementioned drawbacks and such object is attained thanks to a foldable wheel of the type defined in the pre-characterising part of claim 1, whose peculiar characteristic resides in that the spokes are pivoted to the hubs substantially on the wheel axis and in that in the collapsed condition the sectors of the rim extend longitudinally between the two hubs.

The pivoting of the spokes around the wheel axis enables, contrary to the case of the prior art wheel mentioned in document US-2015/0084398 in which the spokes are pivoted at the peripheries of the hubs, considerably reducing the overall radial dimensions of the wheel in the rim collapsed condition, due to the longitudinal or axial arrangement of the sectors of the rim in the collapsed condition. In addition, such arrangement advantageously enables the folded wheel to assume a general roller-like configuration due to which it can for example be dragged on the ground rolling, thus not necessarily lifted for transportation thereof.

This advantage is further amplified by the fact that, according to another characteristic of the invention, the two hubs are predisposed to receive respective lateral rollers, for example of the omni ^¬ directional type. This enables the folded wheel to be profitably used in several applications for equipping vehicles of various kinds and types such as for example trolleys, strollers, wheelchairs, scooters, trolley bags, etc.

According to a preferred embodiment of the invention, the foldable wheel according to the invention comprises an axially extensible and contractible central shaft carrying the two hubs, and the spokes are configured in groups in which each group includes a first spoke which pivotly connects a hub with a sector of the rim, and a second spoke which pivotly interconnects the other hub with said sector of the rim and it is pivoted to the first spoke in a scissor-like fashion.

In a variant, the central shaft is formed by two separable axial parts.

The sectors of the rim are preferably, though not necessarily, six.

Brief description of the drawings

The invention will now be described in detail, purely by way of non-limiting example, with reference to the attached drawings, wherein:

- figure 1 is a lateral elevational view of a foldable wheel according to the invention, in the extended condition,

- figure 2 is a plan view of figure 1,

- figure 3 is a view analogous to figure 1 showing the wheel in the collapsed condition, - figure 4 is a plan view of figure 3,

- figure 5 is a perspective view of the wheel in the extended condition,

- figure 6 is a view analogous to figure 5 showing the wheel when passing from the extended condition to the collapsed condition,

- figure 7 is a perspective view of the wheel in the collapsed condition,

- figure 8 is a diametrical sectional view of the wheel in the extended condition, in which the rim was omitted for illustration simplicity purposes,

- figure 9 is a view analogous to figure 8 when passing from the extended condition to the collapsed condition,

- figure 10 is a view analogous to figures 8 and 9 showing the collapsed condition,

- figure 11 is a perspective view and in larger scale showing a detail of the wheel when passing from the collapsed condition to the extended condition,

- figures 12 and 13 are further perspective views and in larger detail analogous to figure 11,

- figure 14 is a perspective view of the wheel in the extended condition in which all sectors of the rim except one were removed for illustration simplicity purposes,

- figures 15 and 16 are two perspective views of the wheel in collapsed condition to which auxiliary rolling elements are applied,

- figures 17 to 26 schematically exemplify various examples of application of the foldable wheel according to the invention,

- figure 27 is a perspective view of a variant of the wheel in the extended condition,

figure 28 shows the wheel of figure 27 in a solely partly collapsed condition, and - figure 29 shows a part of figure 28 in larger detail from a different angle.

Detailed description of the invention

Initially with reference to figures 1, 2, 8 and 14 the foldable wheel according to the invention, indicated with 1A in the extended condition of normal use thereof, essentially comprises a rubberised rim 2, a pair of coaxial hubs 3, 4 and a series of spokes generally indicated with 5 which pivotly interconnect each hub 3, 4 with the rim 2.

The rim 2 is in turn formed by a series of sectors 6 each of which includes an arched rubber portion 7 carried by a rigid support 8 which, in the extended condition of the wheel 1A, extends according to an edge of the rim 2.

In the case of the illustrated example, the sectors 6 are six, same case applying to the group of spokes 5. However, within the present invention there may be provided for solutions with a greater number of sectors, with the aim of attaining greater compactness of the wheel in the folded condition thereof.

As observable in larger detail in figures 8 and 14, the hubs 3, 4 are mounted on a central shaft 9, axially extensible and contractible for example in a telescopic fashion, and the spokes 5 are pivoted to respective support appendages 10, 11 of the hubs 3, 4, substantially on the wheel axis defined by the shaft 9.

As better observable in figures 8, 9 and 14 each group of spokes 5 comprises a first spoke 12 whose radially internal end is pivoted to the support 10 of the hub 3 and a spoke 13 whose internal end is pivoted to the support 11 of the hub 4. The spokes 12 and 13 are centrally pivoted to each other in a scissor-like fashion 14, and carry, at the respective radially external ends, locking members 15, 16 shaped as represented in detail in figures 11-13 so as to cooperate with the ends of the supports 8 of the sectors 6 of the rim 2. In particular, the members 15 are configured to as to enable the rotation of the sectors 6 from closed to open with two distinct rotational axes for the respective contiguous sectors 6, as illustrated in figure 13, besides rotating on the relative spoke 13 so as to maintain a parallelism condition with the corresponding hub when unfolding the wheel. The members 16 act in a manner such to stably and rigidly hold the rim 2 in the extended condition.

Figures 3 and 4 represent the foldable wheel in the collapsed condition, indicated with IB: in such configuration, the hubs 3, 4 are axially spaced from each other, the groups of spokes 5 extend substantially axially along the central shaft 9, adjacent with respect thereto, and the sectors 6 of the wheel 2 also extend longitudinally between the two hubs 3, 4, externally to the groups of rays 5.

Figures 5, 6, 7 and 8, 9, 10 exemplify the passage of the wheel from the extended condition 1A (figures 5 and 8) to the collapsed configuration IB (figures 7 and 10) passing through an intermediate configuration 1C (figures 6 and 9), and vice versa, as follows. After unfolding the locking elements 15, 16 from the sectors

6 of the rim 2, the hubs 3, 4 are mutually axially moved apart by the extension of the central shaft 9, while the spokes 12, 13 of each group 5 simultaneously rotate with respect to each other in a scissor-like fashion (figures 6, 9) until they are arranged substantially parallel to the central shaft 9 (figures

7 and 10) .

As observable in the collapsed condition of figures 3, 4 and 7, the wheel IB has an extremely small and compact overall dimension which facilitates manual transportation thereof, for example as represented in figure 18. However, given that the collapsed wheel IB is evidently generally roller-shaped, it may also be rolled on the ground without necessarily having to be lifted. For this purpose, the invention provides for possible use of a pair of auxiliary rollers 17, represented in figure 15, selectively applicable to the hubs 3, 4. The rollers 17 are conveniently annular- shaped and are applicable on hubs 3, 4 through reversible fitting members non (not illustrated in detail) for example of the snap-coupling type.

The auxiliary rollers may also advantageously be of the omni-directional type, as indicated in the references 18 in the figure 16.

The foldable wheel according to the invention is susceptible to various applications on vehicles of various kinds and types, both in the extended and collapsed condition.

Thus, figure 17 shows the application of a pair of wheels, in extended condition 1A, to a bicycle B. In the case of figure 19 the same wheels 1A are applied to a bicycle C collapsible and transformable for example into a stroller P whose wheels IB derive from the folding of the wheels 1A.

In the case of figure 20 the extended wheels 1A are applied to a first aid stretcher S, while the wheels in collapsed condition IB are applied to a trolley D.

Figure 21 represents the application to a foldable wheelchair R, and figure 22 to a drone or robot trolley F.

Figure 23 shows the transformation of a collapsible vehicle, for example made up of an electrically driven cycle C, in a vehicle V, in which the wheels in extended condition 1A of the cycle C are arranged in the collapsed condition IB and they are also provided with auxiliary wheels 17 and 18. In addition, the vehicle V is further collapsible in the configuration indicated with VI.

Figures 24 and 25 show how the motorised vehicle V can be comfortably carried on the shoulder and the collapsed motorised vehicle VI moved like a trolley bag, and figure 26 shows the application of the wheels in the collapsed condition and with the auxiliary rollers 17 and 18 - to a scooter M.

Figures 27-29, in which parts identical or similar to the ones described previously are indicated with the same reference numbers, show a variant of the foldable wheel according to the invention which is currently considered the preferred embodiment and differs from the solution described above substantially due to the following aspects.

Firstly, the central shaft 9 on which the hubs 3, 4 are mounted is formed by two parts 9a, 9b axially separable from each other and each one of which is structured in an extensible and contractible telescopic fashion, as illustrated further in detail in figure 29. This solution enables advantageously further reducing the overall dimension of the wheel in the collapsed condition thereof due to the possibility of a greater capability to mutually move apart between the hubs 3 and 4.

Secondly, the locking members 15 cooperate with the guide tracks 20 fixed in the sectors 6 with the aim of making the rotational movement thereof between the extended and the collapsed conditions of the wheel more fluid .

Lastly, the spokes 5 are provided with projecting rubber lugs 21 suitable to be interposed, in the unfolded condition of the wheel, between every pair of contiguous sectors 6.

Figure 29 shows - partly in detail - the parts 9a, 9b of the shaft 9, the guides 20 and the lug 21. Further shown is the distinctive cross-section of the rubber potions 7 engaged with the relative supports 8 of the sectors 6.

Obviously, the described applications are just examples of the various possible uses of the foldable wheel according to the invention, whose construction details and embodiments may widely vary with respect to what has been described and illustrated, without departing from the scope of protection of the present invention as defined in the claims that follow.

Thus, for example to the hubs 3, 4 there may be associated lateral modules that can be disassembled for the application of the auxiliary wheels 17 or 18, as well as possible pedals. In addition, in order to guarantee maximum stability of the wheel in the collapsed condition, the spokes 5 may also be provided with respective locking members.