Patent Application
20180192734
This application claims priority to European Patent Application No. 17 150 718.9, filed Jan. 9, 2017 the entire contents of which are incorporated herein by reference.
The invention relates to a shoe having a sole structure and an air pump device for blowing air into the interior of the shoe, the air pump device comprising a bellows made from an elastic plastic material, formed in the sole structure and surrounding a cavity, an intake channel for transporting air from an intake opening into the bellows, and an air supply device formed in the sole structure for forwarding air from the bellows into the interior of the shoe.
Such a shoe is known for example from the documents EP 2 218 348 A1 and WO 2012/126489 A1. In the known shoes of the kind described above, the sole structure may have a multilayer construction in the heel area, wherein an intermediate layer containing the cavity is made from a material (soft polyurethane foam for example) that is intended to be more elastic or more compressible than the material of the outsole. The cavity and the compressible plastic layers that surround it form a bellows. The air pump device is designed so that, in an alternating manner in response to a walking movement of a user, air is sucked into the cavity of the bellows from outside the shoe via the air intake channel when a load is removed (the shoe is lifted off the ground) and air is blown out of the bellows into the shoe interior through channels of an air supply device when a load is applied (when the shoe comes into contact with the ground and supports the user's weight). A first valve is arranged in the air intake channel and is designed to allow air to pass only in the direction from outside the sole structure into the cavity. A second valve is arranged in the air supply device, and is designed to allow air to pass only in the direction from the cavity to the channels. The pump effect is supported further still by the outsole having a raised area in the region of the bellows on the outer tread, which area is pressed toward the upper part of the sole when the load of the user's foot is placed upon it. The teaching of EP 2 218 348 A1 includes the suggestion to arrange the intermediate sole between a hard outsole and a further sole, wherein the intermediate sole should be manufactured from a material that is more compressible (more elastic/softer) than that of the outsole and the further sole.
In order to achieve good ventilation of the shoe interior, that is to say effective airflow, it is essential that during walking at each step, on the one hand, a sufficiently large quantity of air is sucked into the bellows from the outside and on the other hand that it is then blown out of the bellows into the shoe interior. In order for the greatest possible quantity of air to be blown into the shoe interior when the load is applied during each step, not only must the volume of the bellows be maximized; it must also be ensured that when the load is applied, the bellows is compressed almost completely, or at least to a great degree, so that the air contained is forced out. Complete or substantial compression can be achieved by making the sole structure surrounding the cavity very supple or soft, so that it is completely compressed by the effect of the bodyweight. However, the bellows must also expand and fill with air as completely as possible thereafter, when the user lifts the foot with the shoe, and before the next treading (in the next step). Such a restoring action is achieved with a sole material surrounding the cavity that is as elastically hard as possible. However, this conflicts with the previously stated requirement for a soft material.
In order to support the restoration of the bellows, from EP 1 093 729 A1 and EP 0 624 322 A1 for example, it is known to arrange helical springs vertically inside the cavity in such manner that they are compressed when the bellows is compressed. These constructions are expensive to make, they require a relatively large installation space, and in shoes that are exposed to heavy use they have a short service life.
In the light of the considerations, it is an object of the invention to create a shoe having a sole structure and an air pump device for blowing air into the interior of the shoe that enables the greatest possible airflow during each step of a walking or running motion together with a long service life even when the shoe is subjected to heavy use (as is particularly the case with running shoes).
According to the invention, this object is solved by a shoe having the features of claim 1.
In a shoe according to the invention with a sole structure and at least one air pump device for blowing air into the interior of the shoe, the air pump device (or at least one of the air pump devices, respectively) comprises a bellows made from an elastic plastic material formed in the sole structure and surrounds a cavity, an intake channel for transporting air into the bellows from an intake opening, and an air supply device formed in the sole structure for forwarding air from the bellows into the interior of the shoe. In some embodiments, the intake channel and/or the air supply device may comprise several conduits (e.g., tubes or pipes) operating in parallel. On the other hand, in some embodiments the intake channel and the air supply device may comprise a common duct section which opens into the cavity. Preferably, the intake channel and the air supply device comprise one-way valves to ensure the desired direction of air transport. Here, the term “bellows” is intended to denote the function of a device that completely surrounds a volume of air (except for openings for the intake channel and the air supply device) and which expresses air through at least one opening when the bellows is compressed and sucks air in when the bellows expands. For example, the bellows may be formed solely by the walls of the cavity or by a bladder fitted inside the cavity (made from a soft, elastic plastic, for example). The (or at least one) air pump device in the shoe according to the invention further comprises a V-shaped or U-shaped spring element that clasps the bellows. An upper leg of the V-shaped or U-shaped spring element comprises an upper pressure plate arranged over the bellows and under an insole of the sole structure, and a lower leg of the V-shaped or U-shaped spring element comprises a lower pressure plate arranged under the bellows and over an outsole layer of the sole structure, a joining section of the spring element coupling the two legs being arranged beside the bellows in the sole structure. The term “V-shaped or U-shaped spring element” is not to be interpreted here in limiting manner, meaning that the legs should always be exactly the same length and straight; they may also be of different lengths or slightly curved. An arrangement “over an outsole layer” should here also include an arrangement over one of a plurality of outsole layers or inside one outsole layer. The air pump device (or any of multiple air pump devices) is arranged such that the V-shaped or U-shaped spring element is deformed elastically by pressing the pressure plates together during a walking motion when the sole structure is loaded by the weight of the shoe wearer, the deformation taking place substantially at or close to the coupling section, so the pressure plates above and below the at least one bellows substantially keep their shape, and the bellows arranged between the pressure plates is compressed. The air pump device (or each of the air pump devices) with bellows, intake channel, air supply device and spring element is thus embedded in the sole structure (in preferred exemplary embodiments except for a portion of the intake channel, which is routed out of the sole structure, preferably in or along the upper, upward to one or more intake openings). This sole structure, in which the air pump device (or each of the air pump devices) is embedded, may be produced from a single plastic material, for example. However, the sole structure preferably has a multilayer construction. This multilayer construction preferably comprises at least one insole, at least one intermediate layer made from a compressible material (intermediate sole) containing the bellows and the spring element, and at least one outsole layer arranged below it. Consequently, the term “insole” is intended here to refer to any uppermost sole layer between the shoe interior and the upper pressure plate. In some embodiments, the insole may have a multilayer construction. For functional purposes, the insole in this case should be considered as part of the sole structure, although it is usually part of the upper for the purposes of shoemaking. The coupling of the insole to the upper may be made by any means (e.g., lasted, cement lasted, Strobel construction, Goodyear welting or double stitching). The intermediate layer (intermediate sole) and the outsole layer are preferably made of different materials (each of which is adapted to its various functions), but in one embodiment they may also be manufactured from the same material.
The solution according to the invention provides a shoe that enables a high airflow rate during each step of a walking or running motion and a long service life even with heavy use (as occurs particularly with running shoes). The solution according to the invention not only ensures that the bellows regains its shape faster and more completely during expansion; it also supports the bellows compression due to the expansive distribution of the compressive force by the upper and lower pressure plates, which substantially retain their shape when pressed together.
The shoe preferably has a single air pump device. The bellows of the air pump device is arranged in the heel area of the shoe, and the V- or U-shaped spring element extends substantially over the entire heel area. The coupling section is thus arranged in a joint area of the shoe and/or in a peripheral area of the heel area adjacent to the joint area This preferred arrangement of the bellows with the spring element clasping it enables a high pumping capacity and at the same time cushions the running motion and absorbs impact when the heel area comes into contact with the ground, particularly in a running shoe.
A preferred embodiment is characterized in that a support section is formed on the coupling section in the opposite direction to the legs, so that the spring element is Y-shaped, wherein the support section protrudes into the joint area of the shoe to no more than about 10 mm in front of a ball-of-the-foot area in the forefoot area. This stabilizes the position of the spring element in the sole structure and spreads the forces exerted on the adjacent sole material at the leading edge of the spring element when the spring element is deformed, so that the sole material is exposed to lower loads and the shoe therefore remains serviceable for longer.
In a preferred further development, at least one stabilizer spring element (preferably one stabilizer spring element each) is arranged next to the bellows on both sides. Each of the stabilizer spring elements is coupled to lateral peripheral areas of the upper and lower pressure plates in such a manner that said elements are compressed elastically when the pressure plates are pressed together, wherein the elasticity of the stabilizer spring elements arranged on both sides of the shoe is adjusted (dimensioned) such that they are pressed together to approximately the same degree when load on the sole structure due to the weight of the wearer during a running motion causes them to be pressed together, which has the effect of counteracting a rotation of the upper pressure plate with respect to the lower pressure plate about an axis parallel to the lengthwise direction of the shoe. This stabilizes the position of the foot during the compression of the sole structure in the heel area that takes place when a wearer is running and reduces the danger of turning the ankle to the side (distortion). Due to the fact that the force acting on the stabilizer spring element(s) arranged on the outer side of the shoe may differ from the force acting on the stabilizer spring element(s) arranged on the inner side of the shoe, the elastic properties of the stabilizer spring element(s) located on both sides of the shoe should be set differently. The required (different) elastic properties of the outer and inner stabilizer spring elements may be calculated on the basis of models or determined experimentally.
Preferably, each of the stabilizer spring elements is coupled in torsion-resistant manner to lateral peripheral areas of the upper and lower pressure plates in such a manner that a relative movement of the upper and lower pressure plates in the lateral directions is prevented or at least impeded. This too helps to further stabilize the position of the foot. In a preferred embodiment, the stabilizer spring elements arranged on both sides of the bellows are coupled to each other via a bridge arranged on the rear edge of the heel area. This stabilizes the torsion-resistant coupling with the lateral peripheral areas.
The stabilizer spring elements preferably each comprise at least one V-shaped or U-shaped spring section, which is arranged in such manner that the legs thereof move closer to one another when the stabilizer spring elements are compressed. In a simple embodiment, each of the stabilizer spring elements may only consist of one V- or U-shaped spring element, of which the upper leg is coupled to the upper pressure plate and the lower leg is coupled to the lower pressure plate. Other embodiments may comprise bridges arranged in the manner of a grid in a vertical plane, multiple pairs of such bridges or bridge sections each forming V- or U-shaped spring elements.
In one exemplary embodiment, the lateral peripheral areas of the upper and lower pressure plates, to which the stabilizer spring elements are coupled, form bearing surfaces for respective upper and lower ends of the stabilizer spring elements. The ends of the stabilizer spring elements in contact with these peripheral areas have corresponding bearing surfaces which are permanently attached by adhesion or some other means to the bearing surfaces of the peripheral areas of the pressure plates.
The peripheral areas arranged on both sides of the lower pressure plate are preferably each separated from the middle area of the lower pressure plate located below the bellows by a gap or slit which is open towards the back side of the shoe, so that both peripheral areas of the lower pressure plate form separate spring legs. The middle area of the lower pressure plate located between the two gaps projects downward, so that the pressing together of the bearing surfaces and therefore of the stabilizer spring elements does not begin until after the middle area of the lower pressure plate and the upper pressure plate have been pressed together by a predetermined distance. This makes it possible for a part of the bellows volume to be compressed even without the effect of the stabilizer spring elements so that the bellows volume can be partially increased at the expense of some stabilizing effect. The optimum between a bellows volume to be maximized (significant projection of the middle area) and an adequate stabilization of the foot (early actuation of the effect of the spring elements due to a small projection of the middle area) may be calculated on the basis of models or determined experimentally.
A preferred embodiment is characterized in that the stabilizer spring elements are fastened detachably or replaceably. In a further preferred embodiment, the stabilizer spring elements comprise a device for adjusting the spring force. Both embodiments enable an adjustment to the bodyweight of the shoe wearer.
An advantageous further development of the shoe according to the invention is characterized in that folds are formed in the side walls of the bellows on the open sides of the V- or U-shaped spring elements. The precise arrangement of these folds enables the nature of the deformation of the bellows to be defined when it is compressed with a low wall thickness, which in turn allows a larger bellows volume.
The shoe according to the invention is preferably characterized in that the intake channel coupled to the bellows for transporting air from an intake opening to the bellows has a minimum cross sectional area of 3 mm2, for shoe sizes longer than about 25 cm, a minimum cross sectional area of 4 mm2. This minimum cross section ensures a lower flow resistance when the air is sucked in, and thus contributes to a faster, and accordingly (given the restoring time limited by the time taken for a step) largely complete restoration when the bellows expands. In this context, the intake opening is preferably spanned by a dirt-repellent mesh (e.g., plastic mesh or net) and has a larger minimum area than the minimum cross sectional area of the intake channel to compensate for the greater flow resistance caused by the dirt-repellent mesh.
Advantageous and/or preferred further developments of the invention are characterized in the subordinate claims.
In the following, the invention will be explained in greater detail with reference to preferred exemplary embodiments represented in the drawings. In the drawings:
A first preferred exemplary embodiment of the shoe 1 according to the invention is shown in
The air pump device of the shoe 1 shown in
Bellows 4 is clasped by a V-shaped spring element 9, which in the embodiment shown here is Y-shaped (see
As is particularly evident in
As is shown in
As is shown in
The V-shaped spring element 9 has a connecting section 14 which connects upper leg 10 and lower leg 11 to each other. The V-shaped spring element 9 is deformed by pressing together pressure plates 13 and 12, this deformation taking place essentially at connecting section 14 or in those areas of legs 10 and 11 that are located close to connecting section 14. In this process, the pressure plates substantially retain their shape, so that pressure plates 12 and 13 press against the upper side and the underside of the bellows over the largest area possible. Pressure plates 12 and 13 should not be deformed in those areas where they act on the upper side or underside of bellows 4 in such a manner that bellows 4 can no longer be pressed together over the entire horizontal extension thereof. In particular, a pointwise pressing-in of pressure plates 12 and 13 should be avoided. The V-shaped spring element 9 also has a support section 19 which serves to brace and stabilize the position of the V-shaped spring element 9 inside a sole structure, particularly inside a soft intermediate layer of the sole structure. As may be seen in
The V-shaped spring element 9 is produced from an elastically resilient material, an elastic plastic material, for example, particularly a thermoplastic elastic material such as a fiber-reinforced polyamide (e.g., nylon) or a polyether block amide (e.g., VESTAMID or PEBAX). In a preferred embodiment, the V-shaped spring element is made from a carbon fiber reinforced composite material. The plastic bladder that surrounds the cavity of bellows 4 is manufactured from a polypropylene or a polyurethane for example. The air pump device with bellows, V-shaped spring element 9, air supply device and intake channel is preferably embedded in a supple elastic (compressible) plastic material of an intermediate layer of the sole structure (intermediate sole 38). The outsole layer 16 attached to the underside of the shoe is made from an abrasion-resistant plastic material. The materials of bellows 4, V-shaped spring element 9 and the intermediate layer of the sole structure and outsole layer 16 are matched to each other and connected to each other in such manner that the materials are hardly detached at all at the boundary surfaces thereof, even under heavy, continuous load. The distribution of forces produced in this process, particularly at spring element 9 is assured by the aforesaid support section 19.
Besides the bellows 4, the air pump device comprises an intake channel for transporting air from an intake opening 6 into bellows 4 and an air supply device formed in the sole structure for forwarding air from bellows 4 into the interior of shoe 1. These channels are not shown in
To manufacture the sole structure with air pump device, first for example a plastic bladder of bellows 4 (also called “lung”) is produced, and this is then inserted between upper leg 10 and lower leg 11 of spring element 9, whereby the stabilizer spring elements are also fastened. Then the entire assembly is overmolded with a soft elastic plastic material (thereby forming an intermediate sole 38), after which the further components of the sole (e.g., outsole layer) may also be overmolded and the upper may be attached adhesively to the insole. Alternatively, a prefabricated air pump device assembled from bellows, intake channel, air supply device, V- or U-shaped spring element and stabilizer spring elements may also be glued together or joined in some other way with a prefabricated intermediate sole or a plurality of prefabricated intermediate sole parts, which may then be followed by attaching the outsole layer and the upper to the insole.
The air pumping function in the shoe 1 according to the invention is explained in greater detail with reference to
When the load is then removed from the heel area, the state according to
During normal running movements, the states shown in
First,
After the shoe wearer places his weight on the foot, first the middle area 33′ of lower pressure plate 13′ is moved upward, causing bellows 4 to be compressed, with the result that—as explained with reference to
Preferred embodiments of the shoe according to the invention have been described with reference to
Many alternative embodiments are conceivable within the scope of the inventive idea. For example, the division of the lower pressure plate 13 of the V- or U-shaped spring elements 9 into a middle area 33 acting on bellows 4 and two peripheral areas 24 and 25 acting on the stabilizer spring elements may also be omitted, in which case stabilizer spring elements 22, 23 may be constructed in such a manner that they initially counteract a compression with a relatively low force in a first portion of the compression path, and this force increases steadily as the compression proceeds. The V- or U-shaped spring element 9 may comprise multiple different material layers. In other exemplary embodiments, spring element 9 and stabilizer spring elements 22 and 23 may also be constructed as a single part.
Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of the invention as defined in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 17 150 718.9 | Jan 2017 | EP | regional |
