DESCRIPTION

The present invention relates to an anatomically designed footwear bottom made of natural or synthetic thermoplastic materials and to a footwear provided with said bottom.

Footwear bottoms molded from thermoplastic materials and suitable for increasing the user’s comfort, in particular during walking, have been known for long time.

Two different types of bottoms are known: anatomically designed bottoms and ventilated bottoms that use external-internal air flows to cool and massage the user’s foot. Anatomically designed bottoms are provided with an arch support that is suitable for perfectly adjusting to the anatomical profile of the foot and is therefore capable of guaranteeing a correct, comfortable support of the foot. Similar arch supports often have an elastically deformable, soft structure that perfectly meets the requirements during the different walking phases. Said arch supports provide a selective compression and a successive expansion depending on whether it is the metatarsal area or the heel area that hits the ground.

Ventilated bottoms have a sole provided with a plurality of valves capable of favoring the ejection of the air contained inside the upper at every step of the user, thus ensuring a cooling air exchange that certainly increases foot comfort.

US2019/0223539 discloses a footwear bottom comprising a sole, a midsole disposed over the sole in such a way to form a chamber, and a first insert, a second insert and a third insert disposed in the chamber. The first insert is suitable for being disposed under the heel. The third insert is suitable for being disposed under the metatarsus and the second insert is suitable for being disposed under a central portion of the foot. The first insert and the third insert are made of a molded plastic material; instead, the second insert consists in a cell filled with microspheres according to the rigidity to be obtained.

Obviously, being composed of a cell filled with microspheres, the second insert cannot be compressed or expanded as a pump to suck and eject the air with a pumping effect. Therefore, the footwear of US2019/0223539 is not a ventilated footwear. In fact, US2019/0223539 does not disclose that the chamber wherein the inserts are provided is an airtight chamber and does not disclose the presence of an air flow in said chamber.

Moreover, US2019/0223539 does not contain any teachings on the possibility that said inserts are attached to the midsole or detached from the midsole.

The purpose of the present invention is to disclose a footwear bottom capable of generating an air cushion as supporting base of the foot, wherein the air contained in the cushion is moved during the different walking phases.

Another purpose of the present invention is to disclose such a footwear bottom capable of generating an air cushion that provides a supporting and upward-pushing action for the user’s heel, when the metatarsal area of the foot hits the ground, thus compressing the air cushion portion.

These purposes are achieved according to the invention with the characteristics of the appended independent claim 1.

Advantageous embodiments of the invention appear from the dependent claims.

The footwear bottom of the invention is defined by claim 1.

The bottom according to the invention is provided with an air cushion wherein the air contained inside the bottom is cyclically transferred from the front to the back (and vice versa) of the bottom, depending on whether it is the heel area or the metatarsal area that hits the ground, compressing said air cushion. Because of such an alternated sequence of selective compressions and expansions of the air cushion, the bottom of the invention can perfectly adjust to the specific profile of the user’s foot at every step, acting as an anatomically designed bottom. In fact, the compression of the front portion of the air cushion determines a forced transfer of the air towards the back portion of the air cushion, in correspondence of the heel area of the user’s foot.

For the sake of clarity, the description of the footwear bottom according to the invention continues with reference to the appended drawings, which have a merely illustrative, not limiting value, wherein:

- Fig. 1 is an exploded axonometric view of the bottom of the invention;

- Fig. 2 is an axonometric view of the bottom of Fig. 1 in assembled condition; and

- Fig. 3 is a sectional view of the bottom according to the invention, taken along the sectional plane ll-ll of Fig. 2.

With reference to the figures, a bottom according to the invention is disclosed, which is indicated with reference F.

The bottom (F) comprises a structure (9) of box type or hull type, which comprises a sole (1) and a perimeter edge (2) that rises upwards from the sole in such a way to form a recessed seat.

The structure (9) is obtained from molding an airtight (i.e. airproof) thermoplastic material.

The sole (1) has an upper side (1a). The perimeter edge (2) has an internal side provided with an annular step (3) that protrudes inwards and extends for the entire perimeter edge.

A first insert (4), a second insert (5) and a third insert (6) are disposed on the upper side (1a) of the sole (1), under the annular step (3). The third insert (6) is firmly attached on the upper side (1a) of the sole (1) by means of gluing. The first insert (4) and the second insert (5) may be attached or not to the upper side (1 a) of the sole (1 ).

The first insert (4) occupies a portion of the heel of the bottom and is suitable for being disposed under the heel of the user’s foot. The first insert (4) has a tapered shape with increasing thickness going from a front end to a back end. The first insert (4) is made of a rigid or semi-rigid airtight material. The first insert (4) is preferably made of a microporous material. The second insert (5) occupies a central portion of the bottom and is suitable for being disposed in an area of the plantar arch of the user’s foot. The second insert (5) is made of an elastically compressible, soft material that is suitable for absorbing air. Otherwise said, the second insert (5) is made of a material suitable for containing air in normal conditions, ejecting the air when it is compressed and absorbing the air when it is extended. In this way, the second insert (5) acts as a pump that is suitable for sucking and ejecting the air. The second insert (5) is preferably made of foam rubber.

The third insert (6) occupies a front portion of the bottom and is suitable for being disposed under the metatarsus of the user’s foot. The third insert (6) is made of a rigid or semi-rigid airtight material. The third insert (6) is preferably made of a plastic material. The third insert (6) preferably comprises a base (61) with half-moon shape and a plurality of protuberances (60) that protrude upwards from the base (61).

The bottom (F) also comprises an insole (7) made of an elastically deformable, airtight material that is suitable for acting as a supporting surface for the user’s foot.

The insole (7) is disposed in contact with the annular step (3) of the perimeter edge of the sole and is glued on said step in such a way to generate the formation of a chamber (8) that contains the three inserts (4, 5, 6). In view of the fact that the structure (9) and the insole (7) are made of an airtight material, the chamber (8) is airtightly sealed.

With reference to Fig. 3, the insole (7) has:

- a back portion (7a) disposed over the first insert (4),

- a central portion (7b) disposed over the second insert (5), and

- a front portion (7c) disposed over the third insert (6).

The chamber (8) contains air at atmospheric pressure that is suitable for generating an air cushion. Such an air cushion is mainly generated by the air contained in the elastically compressible, soft structure of the second insert (5).

The insole (7) has a lower side that is disposed and glued in correspondence of said third insert (6), and therefore the third insert (6) is attached to the insole. If the third insert (6) is provided with the protuberances (60), the protuberances (60) of the third insert are glued to the lower side of the insole (7). Instead, the lower side of the insole is not glued to the first insert (4) and to the second insert (5); therefore the first insert (4) and the second insert (5) are detached from the insole and therefore a veil of air can flow between the first insert, the second insert and the insole.

The fact that the third insert (6) is attached to the insole (7) and to the sole (1) is important because if the third insert (6) was not attached to the insole (7), the air pumped in the chamber (8) by the second insert would tend to lift the front portion (7c) of the insole (7) in correspondence of the third insert (6), unpleasantly lifting the toes of the user’s foot.

Instead, the fact that the third insert (6) is glued to the insole (7) prevents the front portion (7c) of the insole from being lifted.

Moreover, if the third insert (6) is provided with the protuberances (60), the fact that the protuberances (60) are glued to the insole (7) provides an air flow between the base (61) of the third insert and the front portion (7c) of the insole, around the protuberances (60), which generates a massaging effect under the toes of the user’s foot.

With reference to Fig. 3, the tapered shape of the first insert (4) generates an empty space (G) between a front portion of the first insert and the insole (7). In this way, the air pumped by the second insert (5) is conveyed in the empty space (F) between the first insert (4) and the insole (7).

Considering that the insole (7) is made of an elastically deformable, airtight thermoplastic material, the chamber (8) cyclically and selectively undergoes compression steps and expansion steps, respectively when a portion of the bottom (F) hits the ground and when the same portion of the bottom (F) is lifted, during walking.

Moreover, said compression and expansion steps of the various areas of the chamber (8) determine a sort of pumping effect of the air contained in the chamber, which results in a cyclical transfer of the air from the area of the chamber (8) under compression to the area of the chamber (8) under expansion. Such a pumping effect is made possible by the elastically deformable structure of the second insert (5) because all the air contained in said second insert (5) is forcedly ejected under pressure towards the other areas of the chamber (8) that are not occupied by the second insert (5).

As it is known, while walking, a foot alternately and cyclically undergoes a phase wherein it hits the ground with the heel, and a phase wherein it hits the ground with the front half of the foot. When the foot hits the ground with its front half, the insole (7) is compressed downwards, in correspondence of its central portion (7b), namely the area over the second insert (5), under the weight discharged on the insole by the user’s foot. Therefore, the height of the chamber (8) is considerably reduced in the central portion (7b) of the insole, in such a way that the insole (7) favors a compression of the air contained in the chamber (8) in correspondence of the central portion (7b) of the insole.

Following such a compression, the air tends to be transferred towards the portion of the chamber (8) that is not compressed. Such a portion of the chamber without compression is situated in the heel area, considering that during said first walking phase only the toe area of the bottom (F), and not the heel area, interferes with the ground.

Considering that the heel area of the chamber (8) is occupied by the first insert (4), which is made of an airtight material, an air pocket is formed between the first insert (4) and the insole (7), favored by the elastic deformation of the insole. Therefore, a pneumatic thrust is created under the back portion (7a) of the insole (7), providing a supporting action for the user’s heel, which contributes to increase comfort during walking.

In view of the above, the bottom (F) can adjust to the morphology and physiology of the foot, just like an anatomically designed bottom, because of the provision of the insole and of the inserts.

Because of its elastic deformation, the insole (7) perfectly adjusts to the movements and the profile of each foot that wears a footwear provided with the bottom (F). Because of its compact, airtight structure, the first insert (4) can offer comfort and stability to the heel area during walking.

Because of its highly compressible, soft structure, which is suitable for absorbing the air, the second insert (5) can offer a very comfortable support to the arch support area, while providing a pumping effect of the air contained in the chamber (8) because of the fact that its thickness can be considerably reduced under pressure.

Being made of a deformable, airproof material, the third insert (6) can offer a stable support to the toe area of the foot, while providing a sort of massaging effect because of the provision of said flexible protuberances (60).