Shoe with ventilation system.

The present application for industrial invention relates to a shoe with ventilation or transpiration system, and in particular to an accident-prevention shoe.

As it is known, a shoe is mainly made of an upper that wraps the foot around and an outsole that is glued to the upper and acts as tread. In traditional shoes the two parts are manufactured separately and then glued. Therefore, before gluing the outsole on the upper, various mechanisms can be inserted in the outsole to obtain a transpiration system. Transpiration systems applied to this type of shoe are available on the market.

In some shoes an bottom is joined to the upper and then the outsole is glued or injection-molded under the bottom. In such a case, it is rather difficult to provide for ventilation systems integrated into the outsole, unless the bottom is suitably modified.

US5,826,349 and US2005/0005473 disclose shoes with ventilation system integrated in the outsole and in the bottom of the shoe.

Such an inconvenience is especially experienced in accident- prevention shoes that require a continuous metal plate in the outsole or a Kevlar sheet in the bottom. It appears evident that in such cases the ventilation mechanism interferes with the metal plate or Kevlar sheet.

To solve these inconveniences, at least partially, solutions are known that provide for realizing a ventilation mechanism in the insole disposed above the bottom of the shoe.

US2008/0313930, US5,996,250, US3,180,039, and DE201 19030 disclose an insole provided with ventilation mechanism.

However, the insoles of the prior art are only realized by coupling two sheets in order to contain the ventilation mechanism. Consequently, the structure of the insole is uncomfortable for the user. Moreover, such a type of insole structure cannot be molded with a suitable soft material, such as polyurethane foam.

The purpose of the present invention is to eliminate the drawbacks of the prior art, disclosing a method for production of a insole with ventilation system that is comfortable for the user.

Another purpose of the present invention is to provide a insole with ventilation system that can be easily combined with a shoe without interfering with the bottom or the outsole of the shoe.

These purposes are achieved by the present invention according to the features claimed in the enclosed independent claims.

Advantageous embodiments are disclosed in the dependent claims.

The insole of the invention comprises a lower layer of polyurethane foam obtained with injection molding and disposed under a ventilation system, with borders folded in such a way to surround the peripheral borders of said ventilation system.

The advantages of the shoe comprising the insole of the invention are evident, since it provides for ventilation of the user's foot and has been studied in such a way that the ventilation system does not interfere with the bottom or outsole of the shoe and is at the same time comfortable for the user.

Additional characteristics of the invention will become more evident after a detailed description that refers to a merely illustrative, not limiting, embodiment, as shown in the enclosed figures, wherein:

Fig. 1 is an exploded top view that shows the various parts of the ventilation system of the shoe of the invention;

Fig. 2 is a top view of a leather sheet that is part of the ventilation system;

Fig. 3 is a bottom view of the ventilation system complete and assembled;

Fig. 4 is a cross-sectional view of the ventilation system assembled;

Fig. 5 is a diagrammatic cross-sectional view of a mold for injection of polyurethane foam for realization of the insole for shoe of the invention;

Fig. 5 A is an enlarged view of the detail contained in the circle A of Fig. 5; Fig. 6 is a cross-sectional view of the semi-finished insole obtained with the mold of Fig. 5;

Fig. 7 is a cross-sectional view of the finished insole after cutting the leather sheet; and

Fig. 8 is a cross-sectional view of a shoe with the insole of Fig. 7.

Now referring to Figs. 1 - 4 a ventilation system according to the invention is disclosed, which is generally indicated with numeral (2).

The ventilation system (2) comprises a lower sheet (3) of soft deformable material, such as soft thermoplastic polyurethane (TPU) with Shore A hardness lower than 65. The lower sheet (3) has a flattened shape, basically similar to the front of the foot.

The lower sheet (3) comprises deformable spacers (31 ) that protrude upwards. As shown in Fig. 4, the spacers (31 ) are shaped as internally empty rectangular projections. This means that the lower side of the sheet (3) is provided with a plurality of recessed seats (34) in correspondence with the spacers (31 ).

A plurality of air spaces (32), which are shaped as communicating channels, is generated between the spacers (31 ). The air spaces (32) are in communication with an outlet channel (33) at the back end of the lower sheet (3). A connection pipe (20) is coupled in the outlet channel (33).

A pump (4) comprises a lower semibody (41 ) and an upper semibody (42) that are coupled to form a pumping chamber (40) (see Fig. 4) which communicates with the air spaces (32) of the lower sheet (3) by means of the connection pipe (20).

The lower semibody (41 ) is made of hard rigid plastic material, such as hard thermoplastic polyurethane (TPU) with Shore A hardness higher than 95. Instead, the upper semibody (42) is made of soft flexible plastic material, such as soft thermoplastic polyurethane (TPU) with Shore A hardness lower than 65. The two semibodies (41 , 42) are coupled by heat sealing or gluing the peripheral portions.

The chamber (40) of the pump communicates with the air outlet pipe (21 ) that extends in the back to be brought out of the shoe. A valve unit (7) is coupled in the front part of the pump (4). Referring to Fig. 1 , the valve unit (7) comprises a rectangular block (70) made of rigid plastic material, which is provided with :

- a U-shaped conduit (71 ) with inlet in communication with the chamber (40) of the pump and outlet in communication with the outlet pipe (21 ); and

- a longitudinal conduit (72) with inlet in communication with the connection pipe (20) and outlet in communication with the chamber (40) of the pump.

The valve unit (7) can be made in one piece with the lower semibody (41 ) of the pump.

A first non-return (one-way) valve (5) is installed at the inlet of the U- shaped conduit (71 ). The first non-return valve (5) permits air flow from the chamber (40) of the pump to the air outlet pipe (21 ) and not vice versa.

For illustrative purposes, the first non-return valve (5) comprises a spherical shutter (50) with a spring (51 ) to maintain the valve normally closed.

A second non-return (one-way) valve (6) is installed in the longitudinal conduit (72). The second non-return valve (6) permits air flow from the connection pipe (20) to the chamber (40) of the pump and not vice versa.

For illustrative purposes, the second non-return valve (6) comprises a spherical shutter (60) with a spring (61 ) to maintain the valve normally closed.

Referring to Fig. 2, an upper sheet (8) is formed of a strip made of leather or imitation leather, with very low thickness and a basically rectangular shape with rounded corners, with higher dimension than the foot. A plurality of transpiration holes (80) is obtained in the front and central part of the upper sheet (8). Instead a plurality of holes (81 ) for fixing to the mold is obtained in a peripheral part of the upper sheet (8), as illustrated below.

Referring to Fig. 3, the upper sheet (8) is disposed above the lower sheet (3), the connection pipe (20), the valve unit (7) and the pump (4). The upper sheet (8) is coupled to the lower sheet (3) and to the pump (4) by means of stitching (82) or gluing, along a peripheral part of lower sheet (3) and pump (4). The function of the leather upper sheet (8) is to maintain the entire ventilation system (2) together during molding. In this way, between the lower sheet (3) and the upper sheet (8) a wrapping is generated, defining a chamber (35) (Fig. 4) formed of air spaces (32) for the passage of air. The holes (80) of the upper sheet communicate with the chamber (35) and the air spaces (32) of the lower sheet. Therefore the air above the upper sheet (8) is extracted by the pump (4) and ejected outside the shoe through the outlet pipe (21 ).

Referring to Fig. 5, the ventilation system (2) is inserted in a mold (100) for injection molding of polyurethane foam. The mold (1 00) comprises a die (1 01 ) and a lid (1 02).

The die (1 01 ) is provided with a back longitudinal hole (1 03) from which the outlet pipe (21 ) comes out to be connected to an external pump (P).

The mold (1 00) is closed with the lid (1 02) that is uniformly disposed above the upper sheet (8) closing the holes (80). The lid (1 02) is provided with vertical pins (1 04) that protrude downwards. Referring to Fig. 5A, the pins (1 04) of the lid cross the peripheral holes (81 ) of the upper sheet and are engaged in suitable seats (1 05) of the die, firmly holding the upper sheet.

Between the die (1 01 ) and the ventilation system (2) a peripheral air space is generated, surrounding the perimeter peripheral border of the ventilation system.

The die (1 01 ) is provided with a plurality of vertical pins (1 06) that protrude upwards, which exert pressure on the lower semibody (41 ) of the pump, which is suitably made of rigid plastic material.

Pressurized air is injected by means of the external pump (P), flowing in the ventilation system (2) in such a way to generate a pressure of about 2 atmospheres inside the chamber (40) of the pump. In such a case, the nonreturn valves (5, 6) are adjusted in such a way to be one-way only in case of low pressure values. The high pressure of the air sent by the external pump allows to force the valve (5, 6) with reverse flow and put the chamber of the pump in pressure.

The pins (1 06) hold the ventilation system (2) against the lid (1 02) in such a way that polyurethane does not enter between the upper sheet (8) and the upper part of the pump (4) during injection or casting. To that end and for higher safety, air is injected inside the pump (4) so that the upper semibody (42) of the pump pushes the upper sheet (8) that perfectly adheres to the lid (1 02).

Now, polyurethane foam can be injected in the mold (1 00), which is disposed under the ventilation system (2), forming a lower layer (9) of polyurethane foam. The polyurethane foam (9) flows in the peripheral air space, under the upper sheet (8), surrounding the perimeter peripheral border of the ventilation system (2). In this way the polyurethane foam also surrounds the peripheral borders of the ventilation system (2).

The ventilation system (2) has been specifically studied to allow for injection molding of polyurethane foam. In particular, the injection molding of polyurethane has been possible because of the materials used for the pump (4) and because of the fact that the chamber (40) of the pump is maintained under pressure during molding.

The injection of polyurethane foam (9) allows for perfect coupling between the lower sheet (3) and the upper sheet (8) ; between the two semibodies (41 , 42) of the pump; between the valve unit (7) and the pump (4); and between the pump (4) and the upper sheet (8).

As shown in Fig. 6, a semi-finished insole (S) is obtained from the mold (1 00), wherein the lower layer (9) of polyurethane foam has perimeter borders (90) that surround the peripheral border of the ventilation system (2) under the upper sheet (8).

The upper sheet (8) has a peripheral portion (84) that protrudes externally with respect to the borders (90) of the polyurethane layer. Accordingly, the upper sheet (8) is cut with shearing process along a cutting line (83) in correspondence with the perimeter border (90) of the polyurethane layer. In such a way, as shown in Fig. 7, a finished insole (S) is obtained, which is compact, stable and comfortable.

Fig. 8 shows a shoe with upper (T) and bottom (1 ) joined to the upper (T). An outsole (1 1 ) is fixed under the bottom (1 ).

The insole (S) comprising the ventilation system (2) is disposed on the bottom (1 ). A hole (1 0) is made in the heel area between bottom (1 ) and upper (T) to pass the air outlet pipe (21 ) in such a way that air is ejected out of the shoe. If necessary, in the heel area of the shoe, a quarter stiffener (15) is disposed between outsole (1 1 ) and upper (T), which is provided with a channel (16) in communication with the hole (10) to guide the ejection of the air out of the shoe.

The insole (S) can be of removable type or can be glued to the bottom

(1 )-

When walking, the user presses the pump (4) with the heel. Consequently, the air is extracted through the holes (80) of the leather strip and ejected from the chamber (40) of the pump outwards, ensuring ventilation inside the shoe.

It must be noted that the ventilation system (2) of the invention does not modify or interfere with the structure of the bottom (1 ) or outsole (1 1 ) of the shoe. Therefore, in case of accident-prevention shoes, metal plates or Kevlar sheets can be disposed in the outsole (1 1 ) or in the bottom (1 ) without interfering with the ventilation system.

Numerous variations and modifications can be made to the present embodiment of the invention by an expert of the art, while still falling within the scope of the invention as claimed in the enclosed claims.