Technical Field

The present invention relates to a wheel for wheeled items, particularly of the type of suitcases, trolleys, shopping carts, strollers, baby carriages and the like.

Background Art

Wheeled items of the type of suitcases, trolleys, shopping carts, strollers, baby carriages and the like are usually provided with a basic body for carrying things and/or people (e.g., objects, personal effects, clothing, goods and children), with at least one gripping element of the type of a handle and with two or more wheels for towing to the ground.

Specifically, each wheel is associated with the wheeled item by means of a connecting element (e.g., a pin), fitted between the two by interlocking, which is adapted to allow the wheel itself to rotate as a result of the wheeled item being towed.

In detail, the wheels of known type are typically provided with a rim element (made of metal or plastic) on which a cylindrical seat is obtained for housing a rotoidal bearing and a rolling body, mounted around the rim element, which is intended to contact the ground directly.

In this regard, it is good to explain that traditional wheels suffer from an important issue, namely, that their rolling on the ground generates considerable noise emission.

In fact, the rolling body is typically made solid and, therefore, does not allow in any way to dampen vibrations due to the roughness of the ground, making the sliding of the wheel on the latter very noisy.

Keeping this fact in mind, it is easy to appreciate that noise pollution due to the towing of wheeled items provided with known wheels is nowadays a rather annoying and disturbing phenomenon, especially in areas of higher concentration of people (e.g., stations, airports, hotels, tourist areas, shopping malls and so on).

To address this issue, a first type of wheels manufactured in accordance with the teachings of patent WO2018224896 is known.

Specifically, within this document, a wheel is described which is substantially provided with a rolling body made of polymeric material (e.g., semi-cured polyurethane), rubber or the like, and with supporting means of the rolling body comprising a central rim element and two side annular flanges. It should be specified that the rolling body of these wheels is provided with two lateral sidewalls which are spaced apart from each other; for this very reason, the rim element comprises a central ridge protruding in a radial pattern which is insertable between one lateral sidewall and the other to allow the rolling body to be assembled on the rim element.

In addition, the rim element is also provided with an inner space into which the annular flanges can be introduced from opposite sides.

Once the rolling body has been mounted on the rim element, therefore, the annular flanges can be introduced into the inner space by clamping them on the lateral sidewalls in a sandwich-like manner.

It is important to specify that due to the special geometry of the aforementioned components, as a result of the assembly of the latter, an air chamber is defined between the rolling body and the supporting means.

In this way, it is clearly possible to dampen the noise caused by the wheel sliding on the ground and, consequently, to tow the wheeled items to the ground without disturbing the public peace in doing so.

Despite this fact, the wheel described in patent WO2018224896 is still amenable to refinement.

In this regard, in fact, it is good to highlight that the wheel manufactured according to patent document WO2018224896 is provided with a large number of components, which makes its production economically burdensome to support.

This same fact also makes the wheel assembly inevitably take a long time to complete, further exacerbating the already high manufacturing costs just mentioned.

It is easy to appreciate that an increase on manufacturing costs and on assembly time translates into a higher retail price to the public, and that this increased price threatens to undermine the overall consumer interest in purchasing the wheel.

What’s more, it should be added that the lateral sidewalls require specific shaping, which, while allowing them to fit between the rim element and the lateral flanges, also results in their considerable thinning.

This fact increases the risk of total or partial disengagement of the rolling body from the supporting means (a phenomenon identified, in technical jargon, by the term “bead-breaking”), thus compromising the practicality and functionality of the wheel manufactured according to patent WO2018224896.

To fix, at least partly, the aforementioned drawbacks, a second type of wheel is known, manufactured in accordance with the teachings of document WO2019193492. Specifically, such wheels are provided with a rolling body and annular flanges quite similar to those of patent WO2018224896, but differ from the latter mainly by the fact that they lack the rim element.

In this case, in fact, the two lateral sidewalls of the rolling body are made close to each other and are placed in mutual contact as a result of clamping the annular flanges in a sandwich-like manner.

This fact allows the air chamber to be defined without requiring any additional components other than the annular flanges and the rolling body, thus optimizing the industrialization of the wheel of patent WO2018224896 with respect to the previous ones.

That said, document WO2019193492 also appears to be amenable to refinements aimed at further improving the efficiency, ease of production and user-friendliness of the wheels described therein.

While able to give the aforementioned benefits, in fact, the expedient of providing close lateral sidewalls is somewhat complicated, particularly evident during production and wheel crash tests.

In this regard, it should be recalled to mind that wheels made of polymeric material or rubber are typically manufactured by means of technological processes of injection molding wherein, as is well known, the molding dies must be shaped in a manner substantially mirroring the shape of the wheel itself.

This characteristic, combined with the special geometry of the rolling bodies involved, means that the production by molding the wheels inevitably involves the presence of undercuts that require the rolling body to be able to flex, by deforming elastically, in order to be removed and extracted from the relevant molds.

With this in mind, it is easy to appreciate that providing lateral sidewalls close to each other ends up by increasing the stiffness of the wheel, thus complicating the removal thereof from the mold and forcing one to use polymeric and/or rubber materials marked by lower shore hardness.

The use of softer polymers, however, results in the production of less durable wheels that, as they deform more under the same load, end up wearing out soon and meeting premature end of life.

In addition to what has just been said, it should be added that the wheels described in the aforementioned patents are perfectible not only from a technological/structural point of view, but also from a purely aesthetic point of view.

It should be kept in mind, in fact, that manufacturing wheels distinguished by refined aesthetic features allows them to be more unique, valuable and distinguishable from the competition, and that these features, being liked and very appreciated by consumers, allow stimulating the latter to purchase the wheel.

Description of the Invention

The main aim of the present invention is to devise a wheel for wheeled items, particularly of the type of suitcases, trolleys, shopping carts, strollers, baby carriages and the like, which enables the reduction of noise pollution caused by towing the wheel to the ground.

One object of the present invention is to devise a wheel for wheeled items, particularly of the type of suitcases, trolleys, shopping carts, strollers, baby carriages and the like, which is quiet, easy to assemble and durable.

Another object of the present invention is to devise a wheel for wheeled items, particularly of the type of suitcases, trolleys, shopping carts, strollers, baby carriages and the like, which is not susceptible to bead-breaking.

Yet another object of the present invention is to devise a wheel for wheeled items, particularly of the type of suitcases, trolleys, shopping carts, strollers, baby carriages and the like, which can be used with equal simplicity and intuitiveness in suitcases and trolleys as well as in other wheeled items such as, e.g., strollers, baby carriages, shopping carts and so on.

A further object of the present invention is to devise a wheel for wheeled items, particularly of the type of suitcases, trolleys, shopping carts, strollers, baby carriages and the like, which has a pleasing, unique and eye-catching appearance and which, precisely by virtue of its aesthetic features, stimulates consumers to purchase it.

Another object of the present invention is to devise a wheel for wheeled items, particularly of the type of suitcases, trolleys, shopping carts, strollers, baby carriages and the like, which allows the aforementioned drawbacks of the prior art to be overcome within the framework of a simple, rational, easy and effective to use as well as affordable solution.

The aforementioned objects are achieved by this wheel for wheeled items, particularly of the type of suitcases, trolleys, shopping carts, strollers, baby carriages and the like, having the characteristics of claim 1.

The aforementioned objects are achieved by this wheeled item having the characteristics of claim 10.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become more apparent from the description of a preferred, but not exclusive, embodiment of a wheel for wheeled items, particularly of the type of suitcases, trolleys, shopping carts, strollers, baby carriages and the like, illustrated by way of an indicative, yet nonlimiting example, in the accompanying tables of drawings in which:

Figure 1 is a side view of the wheel according to the invention applied, by way of an example, to a wheeled item of the type of a trolley;

Figure 2 is an axonometric, exploded view of the wheel according to the invention;

Figure 3 is an axonometric, overall view of the wheel according to the invention;

Figure 4 shows a section, run along the vertical IV-IV plane, of Figure 3;

Figure 5 shows, on an enlarged scale, a detail from Figure 4;

Figure 6 shows the wheel according to the invention in a particular configuration of use.

Embodiments of the Invention

With particular reference to these figures, reference numeral 1 globally indicates a wheeled item provided with one or more wheels according to the invention.

Specifically, the wheeled item 1 comprises: at least one basic body 2 for the transport of things and/or people; at least one gripping element 3a, 3b associated with the basic body 2 and graspable by at least one user; at least one wheel 4 according to the invention associated with the basic body 2 for the displacement of the wheeled item 1 onto the ground.

In this regard, it should be specified that, depending on the type of the wheeled item 1 involved, the basic body 2 and the gripping element 3 a, 3b take on different conformations and structural peculiarities that make them suitable for the special intended use of the wheeled item itself.

To better clarify this concept, some cases are given below as an example.

If the wheeled item 1 is of the type of a suitcase or trolley (as shown in Figure 1), then the basic body 2 consists of a container body for objects, clothing and/or personal effects.

Specifically, in this case, the basic body 2 can be formed by two mutually coupled half- shells.

As for the gripping element 3a, 3b, on the other hand, it is a handle 3a or a grip 3b which can be grasped by the user for towing the suitcase or trolley onto the ground.

The gripping element 3a, 3b can be permanently associated with the basic body 2 (e.g., if it is a handle 3a), or it can be extendable/retractable with respect to the latter (e.g., if it is a grip 3b).

Again, if the wheeled item 1 is of the type of a suitcase or a trolley, then it may comprise two wheels 4, or four wheels 4 paired two by two (in the so-called dual wheel configuration), or a different and, e.g., a larger number of wheels 4.

For example, the wheeled item 1 of the type of a suitcase may consist of a briefcase provided with wheels, or other suitcases still.

Similar to what has just been said for suitcases and trolleys, it is specified that the wheeled item 1 may consist of different but comparable solutions such as, e.g., golf bags (thus intended for transporting golf clubs), three-wheeled trolleys for climbing steps, and so on.

It is worth mentioning that the wheeled item 1 may also be contextualized in the medical sector and be, in this sense, of the type of a hospital bed, or a wheelchair, or a walker, and so on.

In the first case, i.e., of a wheeled item 1 of the type of a hospital bed, then the basic body 2 is intended for weight support of one or more patients lying above and their transportation.

The gripping element 3 a, 3b can be of the type of a handle 3 a which can be grasped by an attendant (such as a nurse, health worker, doctor and so on) for towing the hospital bed onto the ground.

The hospital bed may comprise four wheels 4, or eight wheels 4 coupled two by two, or a different , e.g. a larger number of wheels 4.

In the case, on the other hand, of a wheeled item 1 of the type of a (motorized or not) wheelchair, then the basic body 2 consists of a seat intended for weight support of a person who has walking difficulties, such as an elderly person and/or a person with a medical condition.

In this case, the gripping element 3a, 3b is of the type of a handle 3a.

In addition, the wheeled item 1 of the type of a wheelchair comprises four wheels 4, or a different, e.g. a larger number of wheels 4.

Finally, in the case of a walker, the basic body 2 consists of a seat or one or more rigid support(s) and is intended to support in walking a person with walking difficulties, such as an elderly person and/or a person with a medical condition.

In this circumstance, the gripping element 3a, 3b is of the type of a handle 3a.

The walker may comprise four wheels 4, or it may comprise two wheels 4, or a different still, e.g., a larger number of wheels 4.

Moving away from the medical field, the wheeled item 1 can be of the type of a shopping cart.

In this case, the basic body 2 consists of a container body for the goods that the user has purchased or intends to purchase.

Specifically, the basic body 2 is of the type of a metal and/or plastic cage which is shaped so as to define a rigid basket for containing the goods.

Also in this case, the gripping element 3 a, 3b is a handle 3 a or a grip 3b for towing the shopping cart onto the ground.

In addition, if the wheeled item 1 is of the type of a shopping cart, then it may comprise four wheels 4, or a different and, e.g., larger number of wheels 4.

If, on the other hand, the wheeled item 1 is of the type of a stroller or a baby carriage, then the basic body 2 consists of a shell intended to carry and/or house children inside it.

In this case, the gripping element 3 a, 3b is preferably a handle 3 a for towing the stroller or baby carriage onto the ground, but a grip 3b cannot be ruled out.

In addition, the wheeled item 1 of the type of a stroller or a baby carriage may comprise four wheels 4, or a different and, e.g., larger number of wheels 4.

Finally, the wheeled item 1 may be of the type of a scooter intended to transport a user.

The wheeled item 1 of the type of a scooter may, particularly, be motorized (i.e., provided with one or more electric motors) or non-motorized (i.e., propelled in motion only by the user’s muscle power).

In all cases, the basic body 2 consists of the scooter’s frame and is intended to support the user’s weight while using the scooter.

In actual facts, the user stands with his/her weight on the basic body 2 and operates the scooter in motion by means of either his/her own muscle power or any motors with which the scooter itself is provided.

In the case of the wheeled item 1 of the type of a scooter, the gripping element 3 a, 3b is of the type of a handle 3b which can be grasped by the user for his or her own support, e.g. to remain balanced on the basic body 2, while using the scooter itself.

The scooter may be provided with two wheels 4 arranged parallel to each other, or with four wheels 4 paired two by two, or with an even different number of wheels 4, such as three or eight.

In this regard, it is useful to point out that, regardless of its type, the wheeled item 1 is marketed with its wheels 4 already mounted.

Specifically, the wheeled item 1 comprises a fastening base 28 of the wheels 4 which is associated inferiorly with the base body 2 and with which the wheels 4 are already fastened at the time of purchase.

Basically, the fastening base 28 is of the type of a supporting fork to which one or more wheels 4 are attachable.

Alternative embodiments cannot however be ruled out wherein the wheels 4 are associable with the fastening base 28 after the wheeled item is marketed.

In this case, for example, it is possible to replace one or more of the traditional wheels with which the wheeled items already on the market are provided with a corresponding number of wheels 4 according to the invention, effectively transforming a traditional wheeled item into a wheeled item 1 according to the present invention.

Going into more detail about the wheel 4 for wheeled items, it should first be said that it comprises at least a first annular flange 5a and at least a second annular flange 5b which are provided with at least a first shoulder 6a and with at least a second shoulder 6b respectively, and are coupled to define at least one central groove 7 axially bounded by the first shoulder 6a and by the second shoulder 6b.

The central groove 7 has a substantially cylindrical conformation.

Specifically, the central groove 7 is substantially shaped as a right cylinder.

In particular, the central groove 7 runs lengthwise (where “length” here refers to the dimension that corresponds to the height of the cylinder) between the first shoulder 6a and the second shoulder 6b.

Usefully, at least one of either the first flange 5a or the second flange 5b is at least partly made of at least one plastic material.

In the present case, at least one of either the first flange 5a or the second flange 5b is at least partly made of at least one of polyamide-6 (commonly known by the acronym PA-6) and polyoxymethylene (commonly known by the trade names Delrin, Tecaform, Kepitai, Kematal, Ertacetal, and Zellamid 900).

As will be motivated later in this disclosure, the special expedient of making at least one of either the first flange 5a or the second flange 5b of polyoxymethylene proves to be quite convenient for the efficiency of use and noiselessness of the wheel 4.

Continuing with the description of the wheel 4, this comprises at least one rolling body 8 made at least partly of polymeric material (e.g., semi-cured polyurethane) and/or rubber.

As already explained, the hardness of the rolling body 8 plays a major role in determining the simplicity of production of the latter and, at the same time, its life over time.

In this sense, the hardness of the rolling body 8 is comprised between 45 Shore and 70 Shore, better still between 50 Shore and 65 Shore, preferably between 55 Shore and 60 Shore.

As visible in the magnifying view in Figure 5, the rolling body 8 is provided with at least a first lateral sidewall 9a, with at least a second lateral sidewall 9b and with at least one joining portion 10 associated with the first sidewall 9a and with the second sidewall 9b.

In the present case, the joining portion 10 is the portion of the wheel 4 that makes direct contact with the ground when the wheel itself slides onto the ground.

Specifically, the first sidewall 9a and the second sidewall 9b are fitted in the central grove 7 and comprise at least a first end portion I la and at least a second end portion 11b respectively, placed in mutual contact to define, with the joining portion 10, at least one air chamber 12.

As explained above, providing an air chamber defined solely by means of the first end portion 1 la, the second end portion 1 lb and the joining portion 10 allows the wheel to do without of the additional supporting means such as the rim elements or the like, making the wheel simple to be assembled and, therefore, inexpensive.

According to the invention, the first shoulder 6a and second shoulder 6b comprise at least a first perimeter surface 13a and at least a second perimeter surface 13b respectively, which are substantially cylindrical in shape.

Specifically, the first perimeter surface 13a and the second perimeter surface 13b are shaped as a right cylinder.

More specifically, the radius of the first perimeter surface 13a and of the second perimeter surface 13b are substantially coincident.

Again, the radius of the first perimeter surface 13a and of the second perimeter surface 13b is substantially larger than the radius of the central groove 7. In this very sense, therefore, it is possible to say that the first shoulder 6a and the second shoulder 6b axially bound the central groove 7.

In addition, the length (where “length” refers, again, to the dimension that corresponds to the height of the cylinder) of the first perimeter surface 13a and of the second perimeter surface 13b is substantially less than the length of the central groove 7.

According to the invention, the joining portion 10 comprises at least a first supporting portion 14a, which protrudes axially from the first sidewall 9a and is arranged bearing by weight on the first perimeter surface 13 a, and at least a second supporting portion 14b, which protrudes axially from the second sidewall 9b and is arranged bearing by weight on the second perimeter surface 13b.

In this regard, it is specified that by using the term “axially” (or others similar thereto that share the same linguistic root such as “axial”) we mean to refer to a direction that is parallel to a central axis A of rotation of the wheel 4 and is, together with the latter, substantially orthogonal to a vertical geometric plane.

In order to stand firmly and stably on the first perimeter surface 13a and on the second perimeter surface 13b, the first supporting portion 14a and the second supporting portion 14b are also substantially cylindrical in shape.

In particular, the first supporting portion 14a and the second supporting portion 14b are also shaped as a right cylinder.

In the present case, the radius of the first perimeter surface 13a, of the second perimeter surface 13b, of the first supporting portion 14a and of the second supporting portion 14b are substantially coincident.

In fact, this geometric expedient ensures that the first supporting portion 14a and the second supporting portion 14b are fully bearing by weight on the first perimeter surface 13a and on the second perimeter surface 13b, respectively.

In addition, the joining portion 10 comprises at least a first curved portion 15a and at least a second curved portion 15b which are associated with the first supporting portion 14a and with the second supporting portion 14b, respectively.

Specifically, the first curved portion 15a and the second curved portion 15b are mutually connected and define, in vertical cross-section, at least one profile in the shape of a semicircle (see Figure 4 in this regard).

Conveniently, the first shoulder 6a comprises at least a first outer face 16a bounded peripherally by the first perimeter surface 13a which is substantially flat in shape.

Similarly, the second shoulder 6b comprises at least a second outer face 16b bounded peripherally by the second perimeter surface 13b which is substantially flat in shape.

If we consider the wheel 4 in one of its assembly configurations, wherein its constituent components are mutually assembled, then the first outer face 16a and the second outer face 16b face outwards from the wheel 4.

In this sense, therefore, the use of the adjective “outer” in the context of the first outer face 16a and of the second outer face 16b is intended to mean that these are visible from the outside when the wheel 4 is in the assembly configuration.

In this regard, it is important to specify that the first outer face 16a defines with the joining portion 10 a respective seamless surface.

Similarly, the second outer face 16b defines with the joining portion 10 a respective seamless surface.

To better explain this concept, it is useful to consider that, given the geometric conformations previously described, the first outer face 16a defines a first edge with the first perimeter surface 13a and the second outer face 16b defines a second edge with the second perimeter surface 13b.

In the same way, the first supporting portion 14a defines a third edge with the first curved portion 15a and the second supporting portion 14b defines a fourth edge with the second curved portion 15b.

Keeping this in mind, to say that the first outer face 16a and the second outer face 16b define with the joining portion 10 respective seamless surfaces is to mean that the first edge and the third edge are substantially overlapping and that the second edge and the fourth edge are, also, substantially overlapping.

To further explain this concept, it may be convenient to provide another example, and in particular to consider that a line tangent to the profile of the wheel 4 does not encounter, between the joining portion 10 and the outer faces 16a, 16b, any kind of geometric discontinuity passing from the former to the latter or vice versa.

Going into more detail, it is noted that the line tangent to the joining portion 10 inclines with increasing slope as, moving along one of either the first curved portion 15a or the second curved portion 15b, it moves closer to the first outer face 16a or to the second outer face 16b, respectively.

As it continues to move along one of either the first curved portion 15a or the second curved portion 15b, the tangent line becomes closer and closer to the vertical line, until it is arranged substantially vertically at the connecting point between the curved portions 15a, 15b and the outer faces 16a, 16b. To say that the outer faces 16a, 16b and the joining portion 10 define respective seamless surfaces means, therefore, precisely that the crossing of the aforementioned connection occurs in a geometrically continuous manner and without any interruption. The special geometric continuity relationship which has been established between the outer faces 16a, 16b and the joining portion 10 results in an aesthetically valuable effect on the wheel 4 that gives it uniqueness and distinguishability from its competitors.

In this sense, it is easy to appreciate that this feature makes it possible to stimulate consumers to purchase the wheel 4.

The first shoulder 6a comprises, then, at least a first inner face 17a opposite the first outer face 16a which is substantially flat in shape.

Similarly, the second shoulder 6b comprises at least a second inner face 17b opposite the second outer face 16b which is substantially flat in shape.

In accordance with what was previously stated regarding the use of the term “outer”, it is specified that the use of the adjective “inner” in the context of the first inner face 17a and of the second inner face 17b is intended to mean that, in the assembly configuration, the latter are not visible from the outside.

In practice, in the assembly configuration, the first inner face 17a and the second inner face 17b face inwards from the wheel 4.

Conveniently, the first flange 5a and the second flange 5b comprise at least a first through-hole 18a and at least a second through-hole 18b respectively, which are obtained along at least the central axis A of rotation of the wheel 4 and aligned with each other.

In detail, the first through-hole 18a and the second through-hole 18b are adapted to house at least one connecting element 29 of at least one wheeled item 1.

In fact, as already anticipated, the wheeled item 1 comprises a fastening base 28 associated inferiorly with the basic body 2 to which one or more wheels 4 can be attached.

For this purpose, the fastening base 28 has a special fastening through-hole 28a, which can be aligned with the central axis A, through which the connecting element 29 may be fitted.

In this regard, the connecting element 29 may be of the type of a screw, or of an internally threaded hollow pin and of a screw that can be screwed therein, or other types or combinations of connecting elements 29 known to the expert in the field that will, in any case, enable the wheel 4 to be adequately fastened to the fastening base 28 of the wheeled item 1.

This means that, depending on the type of connecting element 29, the latter can be fitted by interlocking in the first through-hole 18 a, in the second through-hole 18b and in the fastening hole 28a, or it can be screwed therein.

In the latter case, special threads can be provided which are obtained on at least one of the first through-hole 18a, the second through-hole 18b or the fastening hole 28a.

As visible in Figure 4, the first through -hole 18a has a substantially larger diameter than the second through-hole 18b.

Again, the second through-hole 18b is sized so that the connecting element 29 can be fitted therein to measure.

For example, in the case of the connecting element 29 of the type of an internally threaded hollow pin and of a screw that can be screwed therein, the pin can be fitted through one of the through-holes 18a, 18b and have it pass through the other of the through-holes 18a, 18b and the fastening hole 28a.

At that point, a screw can be tightened into one end of the pin, fitting it through the first through-hole 18a until it is arranged against the first flange 9a.

In the case of wheels 4 coupled two by two (see Figure 6 in this regard), then it is possible to connect the latter to the fastening base 28 by fitting the pin through the first through-hole 18a of one of the two wheels 4 and then having it pass through the remaining through-holes 18a, 18b and the fastening hole 28a.

At that point, a screw can be tightened into both ends of the pin, arranging them against each of the two first flanges 9a.

Having described the connecting mode between the wheel 4 and wheeled item 1, it is now easy to appreciate that making the first flange 5a and the second flange 5b from polyoxymethylene enables the previously mentioned advantages to be achieved.

In fact, due to the peculiar mechanical properties such as low coefficient of friction, excellent dimensional stability and shock resistance, this material ensures low-friction sliding of the first flange 5a and of the second flange 5b on the connecting element 29, leading to results similar to those that would be obtained by employing a rolling bearing.

Among other things, the use of a first flange 5a and of a second flange 5b made of the aforementioned material ensures the total absence of noise, thus lowering the noise pollution generated by the towing of the wheeled item 1. Advantageously, the first flange 5a is provided with at least one joining edge 19 between the first through-hole 18a and the first outer face 16a which is substantially rounded in shape.

Due to its special rounded shape, the joining edge 19 contributes in making the wheel 4 acquire aesthetic uniqueness and value and, again, in stimulating consumers to purchase the latter.

In the previously described cases, in fact, the screw fitted in the first through-hole 18a goes against the first flange 5a; therefore, the special shaping of the joining edge 19 allows the screw head and the first outer face 16a to be harmoniously joined, thus obtaining a particularly satisfying aesthetic result.

Conveniently, the second flange 5b comprises at least one spacer element 20, visible in Figure 3 and in Figure 6, which is associated with the second outer face 16b in an axially protruding manner and is arranged passing through the central axis A.

In particular, the spacer element 20 has a substantially cylindrical conformation.

More specifically, the spacer element 20 has a straight cylinder conformation.

Keeping this in mind, it is possible to specify that the spacer element 20 is centered on the central axis A; this is equivalent to saying, in fact, that the central axis A coincides with the axis of rotation of the generating line of the spacer element 20.

The fact of providing a spacer element 20 turns out to be a rather convenient technical expedient to ensure that, once the wheel 4 is mounted on the fastening base 28, the former can rotate around the central axis A freely without, therefore, the rolling body 8 going to rub over the latter.

It is easy to appreciate that, if the latter circumstance occurred, the high friction that would be generated would end up complicating the towing of the wheeled item 1 somewhat.

Just in this sense, the spacer element 20 is sized so as to keep the wheel 4 at a fixed distance D from the fastening base 28.

This means that the length of the spacer element (where by “length” is meant, as done above, the geometric height of the cylinder) coincides with the distance D.

What is more, as shown in Figure 6, the spacer element 20 is also quite useful in the case where the wheeled item 1 has wheels 4 coupled two by two (i.e., as mentioned above, in the so-called dual wheel configuration).

Similarly to the previous case, each of the wheels 4 is kept at the distance D from the fastening base 28. In actual facts, the wheels 4 belonging to a pair of wheels 4 are kept at a mutual distance which is equivalent to the thickness of the fastening base 28 added to twice the distance D.

Ultimately, the fact of providing a spacer element 20 allows the wheeled item 1 to be towed absolutely smoothly and efficiently, allowing the wheel 4 to slide freely onto the ground and the total absence of rubbing friction between the rolling body 8 and the fastening base 28.

As previously mentioned, to define the air chamber 12, the first flange 5a and the second flange 5b are clamped in a sandwich-like manner on the first sidewall 9a and on the second sidewall 9b.

For this purpose, the wheel 4 comprises coupling means 21a, 21b of the first flange 5a and of the second flange 5b comprising at least a first coupling element 21a and at least a second coupling element 21b mutually coupleable by complementary shape.

Specifically, the first coupling element 21a is associated with the first flange 5a and the second coupling element 21b is associated with the second flange 5b or vice versa. In the particular embodiment shown in the figures, the first coupling element 21a is associated with the first flange 5a, and the second coupling element 21b is associated with the second flange 5b.

Specifically, the first coupling element 21a is associated with the first inner face 17a, and the second coupling element 21b is associated with the second inner face 17b.

As mentioned, however, the alternative embodiment can be provided in which, therefore, the first coupling element 21a is associated with the second flange 5b and the second coupling element 21b is associated with the first flange 5a.

With reference to the preferred embodiment and with particular reference to Figure 2, the coupling means 21a, 21b comprise three first coupling elements 21a and three respective second coupling elements 21b.

Specifically, as visible, the first coupling elements 21a and the second coupling elements 21b are arranged around the central axis A in a radial pattern at a constant angular distance from each other.

In actual facts, the first coupling elements 21a and the second coupling elements 21b are arranged at 120° from each other.

It cannot, however, be ruled out that the coupling means 21a, 21b may comprise a different number of first coupling elements 21a and of second coupling elements 21b, e.g., four. In this case, it is possible to arrange the first coupling elements 21a and the second coupling elements 21b at a constant distance from each other (in the example just given, therefore, each of the first coupling elements 21a and each of the second coupling elements 21b is arranged at 90° from the other first coupling elements 21a and the other second coupling elements 21b, respectively), or to arrange them at different distances from each other.

In detail, the first coupling element 21a comprises at least one axially developing protruding appendage 22 and at least one pair of fastening teeth 23 which are associated with one end of the protruding appendage 22.

In actual facts, the first coupling element 21a is of the type of an interlocking turret.

In accordance with the preferred embodiment, the first coupling element 21a comprises only one pair of fastening teeth 23; however, it is easy to appreciate that a first coupling element 21a can also be provided with a different number of pairs of fastening teeth 23, e.g. two.

In this alternative case, the various fastening teeth 23 may be arranged in a radial pattern, relative to each other, on the end of the protruding appendage 22.

In all cases, the fastening teeth 23 protrude at least partly in a radial pattern from the protruding appendage 22.

The fastening teeth 23 are elastically compressible by moving close and away from each other; specifically, the fastening teeth 23 are compressible between at least one home configuration, wherein they are arranged at a predefined home distance, and at least one deformed configuration, wherein they are elastically compressed and their mutual distance is smaller than the predefined distance.

In addition, the second coupling element 21b comprises at least one housing channel 24 of the axially formed protruding appendage 22 and at least one bottom opening 25, communicating with the housing channel 24 and having larger width than the housing channel 24, to which the fastening teeth 23 are fastened.

In particular, the bottom opening 25 is formed inside the second shoulder 6b.

Specifically, as visible in Figure 3, the bottom opening 25 is formed passing through the second shoulder 6b and, therefore, communicates with the second outer face 16b.

Conveniently, the housing channel 24 is sized so that the protruding appendage 22 can be fitted to measure.

Again, the housing channel 24 has a depth substantially coincident with the length of the protruding appendage 22. In this way, the protruding appendage 22 can be fitted to its full length into the housing channel 24.

The special geometries described above cause the fastening teeth 23 to be compressed in a radial pattern by the walls of the housing channel 24 where the first coupling element 21a is fitted into the housing channel 24, and thus to be arranged in a deformed configuration, moving them closer together.

Once the protruding appendage 22 is fully fitted into the housing channel 24, the fastening teeth 23 access the bottom opening 25 which, being larger than the housing channel 24, allows them to move away from each other, returning to the home configuration.

In this way, as visible in Figure 3, the fastening teeth 23 can snap into the bottom opening 25, thus counteracting the extraction of the first coupling element 21a from the second coupling element 21b and, therefore, of the first flange 5 a from the second flange 5b.

At this point, it is easy to appreciate that the coupling means 21a, 21b enable the sandwich clamping of the first flange 5a and of the second flange 5b on the rolling body 8 and, in so doing, to obtain a wheel 4 distinguished by a solid and strong assembly.

Conveniently, at least one of either the first flange 5a or the second flange 5b comprises at least one inner seat 26 which is obtained along the central axis A and is intended for housing at least one rotoidal bearing C, shown in Figure 4 by way of an example.

According to the preferred embodiment, only the second flange 5b comprises the inner seat 26.

In particular, the inner seat 26 is substantially cylindrically shaped.

More specifically, the inner seat 26 is substantially shaped as a right cylinder.

Again, the inner seat 26 is centered on the central axis A.

Similarly to what has already been said for the spacer element 20, this is equivalent to saying that the central axis A coincides with the axis of rotation of the generating line of the inner seat 26.

In detail, the inner seat 26 is surrounded peripherally by the second coupling elements 21b.

The fact of providing an inner seat 26 in which to place a rotoidal bearing C clearly makes it possible to facilitate the rotation of the wheel 4 around the central axis A; nevertheless, the possibility of making wheels 4 without the inner seat 26 cannot be ruled out.

Advantageously, the rolling body 8 comprises at least one vent notch 27 which is obtained on at least one of either the first end portion I la or the second end portion 1 lb and is made communicating with the air chamber 12.

Specifically, the vent notch 27 is made on both the first end portion I la and the second end portion 11b.

In detail, the vent notch 27 is obtained in the axial direction, but it cannot be ruled out that it can be cut in different directions, such as transverse to the axial direction.

In accordance with the preferred embodiment, the rolling body 8 comprises four vent notches 27.

In particular, the vent notches 27 are equidistant and placed, therefore, at a constant distance of 90° from each other.

Similarly to what has been said about the first coupling elements 21a and the second coupling elements 21b, wheels 4 provided with a different number of vent notches 27, e.g. three, cannot be ruled out and these may be placed at different distances from each other and, therefore, not constant.

Going into the details, the vent notch 27 is intended to allow the air contained inside the air chamber 12 to be vented outwards.

In this regard, in fact, it is worth mentioning that the air contained within the air chamber 12 can exert a repulsive force on the first flange 5 a and on the second flange 5b that counteracts their sandwich clamping and tends to move them axially away from each other.

Not only that, but the presence of air inside the air chamber 12 can make the towing of the wheeled item 1 noisier, as it reduces the dampening capacity of the wheel 4 against ground roughness.

Keeping all this in mind, it is easy to appreciate that the expedient of providing vent notches 27 somewhat facilitates the clamping of the first flange 5a and of the second flange 5b, also making it possible to obtain a wheel 4 distinguished by remarkably quiet sliding on the ground.

It has in practice been ascertained that the described invention achieves the intended objects.

In particular, the fact is emphasized that the wheel according to the invention enables the reduction of noise pollution caused by towing the wheeled item onto the ground. In fact, thanks to the lateral sidewalls and their placement in the central groove, it is possible to greatly reduce vibrations from the wheel sliding on the ground, thus making wheel towing rather quiet.

Not only that, but such wheels, in addition to enabling quiet wheeled item towing, are easy to assemble and durable.

The fact of defining an air chamber by means of only the end portions and the joining portion makes it possible to do without of supporting means such as supporting rims or the like, thus making the wheel easy to assemble and, therefore, inexpensive.

In addition, the coupling between the annular flanges and the joining portion ensures considerable assembly stability, which is why the wheel according to the invention is not susceptible to bead breaking.

Again, it is easy to guess, by virtue of the description provided, that the wheel according to the invention can be adapted and used with equal ease and intuitiveness in suitcases and trolleys as well as in other wheeled items such as, e.g., strollers, baby carriages, shopping carts and so on.

In this regard, the wheel is quite versatile and can be conveniently employed in a plurality of different contexts and uses.

Finally, the fact is highlighted that the joining edge and the seamless surfaces between the outer faces and the joining portion give the wheel an attractive, unique and eyecatching appearance, which stimulates consumers towards its purchase.