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SHOE UPPER AND METHODS OF
CROSS REFERENCE TO RELATED
This application incorporates by reference, and claims priority to and the benefit of, German patent application serial number 102 22 897.3, filed on May 23, 2002.
The present invention relates to a shoe. More specifically, the present invention relates to a shoe upper and methods of manufacturing the same. 15
Presently, the construction of a shoe upper for a sports shoe requires a substantial amount of manual labor. While 20 the production of a sole of a modem sports shoe can be automated to a great extent, the stitching of the different materials of the upper still requires a significant amount of manual labor.
The upper of a shoe typically includes a soft inner part that provides comfort to the wearer of the shoe. The inner part is stitched to a more stable material, for example, leather, either alone or in combination with different synthetics. The more stable material forms the outside of the 3Q upper of the shoe and provides the desired stability, wear resistance, and support to the wearer's foot. This type of construction results in multiple seams extending over the upper of the shoe. The seams interconnect the outer materials to the softer material(s) of the inner part. As stated 35 above, these seams are typically created manually or semimanually.
A different approach is used to create ski boots for downhill skiing. The complete shoe, i.e., the boot, including the sole, is produced as a single plastic part. Subsequently, 4Q an inner part is inserted into the single plastic part and, if necessary, attached to the surrounding plastic housing. A shoe construction of this type primarily provides protection of the ankle against injuries during skiing. It is, however, usually difficult to walk while wearing these shoes, because 45 the plastic housing lacks flexibility.
It is, therefore, an object of the present invention to provide a shoe, in particular a sports shoe, with a high degree of wearing comfort, but low manufacturing costs. Another object of the present invention is to provide a method of 50 manufacturing a shoe that reduces the amount of manual labor required to produce the upper.
SUMMARY OF THE INVENTION
Generally, the invention relates to a shoe that has an upper that includes a stitch-free shell. In contrast to known shoes, the stability necessary for the upper of the shoe and the desired support of the foot is not provided by additional material layers stitched to the inner shoe, but by a stitch-free 60 plastic shell surrounding only the upper side of the shoe. This shell can be produced at low cost, because the lower side of the inner shoe, which transmits the interaction with the ground to the foot, is not encompassed by the plastic shell. In contrast to ski boots, the flexibility of the shoe in the 65 sole area is completely maintained in a shoe constructed in accordance with the invention.
In one aspect, the invention relates to a shoe having an inner shoe and a stitch-free shell. The inner shoe includes an upper side and a lower side. The stitch-free shell encompasses only the upper side of the inner shoe.
In various embodiments of this aspect of the invention, the stitch-free shell may encompass substantially the entire upper side of the inner show. The stitch-free shell may include a medial half-shell and a lateral half-shell. This facilitates designing the medial and the lateral sides of the upper of the shoe independently from each other, either with respect to their function by, for example, using different materials or material thicknesses, or with respect to their appearance. Additionally, a toe cap may be disposed in a toe area of the shoe and/or a heel cap may be disposed in a heel area of the shoe. The caps can be either directly integrated into the stitch-free shell or be additionally attached from the outside.
In additional embodiments, the stitch-free shell may be constructed of a blow-molded material. Polyurethane (PU) is one example. In a further embodiment, the blow-molded material includes a polyurethane-foil. In an alternative embodiment, the stitch-free shell is composed of a plastic. The blow-molding technique, as well as the use of particular materials, leads to a comparatively flexible plastic shell, such that the upper of the shoe is not too rigid. Furthermore, the use of the PU-foil facilitates the easy design of the appearance of the shoe by printing different patterns on the PU-foil.
In further embodiments, the shoe includes a sole unit. The sole unit is attached to the lower side of the inner shoe. In other embodiments, the sole unit includes a midsole and an outsole. The midsole is attached to the inner shoe and the outsole is attached to the midsole. This construction assures the desired cushioning for the foot of the wearer and the wear resistance necessary for a long shoe life. In one embodiment, the stitch-free shell encompasses the sole unit at least partly about the side. The sole unit may also include a support element disposed in an arch area of the sole. In yet a further embodiment, the stitch-free shell includes at least one recess for receiving the support element.
In another aspect, the invention relates to a method of manufacturing a shoe. The method includes the steps of providing an inner shoe that includes an upper side and a lower side, forming a stitch-free shell, and attaching the stitch-free shell to only the upper side of the inner shoe. The stitch-free shell may be attached such that it encompasses substantially the entire upper side of the inner shoe. The attaching of the stitch-free plastic shell by, for example, gluing the shell to the upper side of the inner shoe, replaces the complicated stitched outer layers of conventional shoe uppers. Further, the shell provides the stability desired for the upper of the shoe.
In one embodiment, the step of forming the shell includes the steps of forming two half-shells and interconnecting the two half-shells to form the stitch-free shell. In various embodiments, the method may include the additional steps of attaching a toe cap in a toe area of the shoe and attaching a heel cap in a heel area of the shoe. In another embodiment, the step of forming the shell includes blow-molding a material, for example, polyurethane, to create the stitch-free shell. In a further embodiment, the forming step also includes binding a PU-foil to the shell. The PU-foil may be a synthetic PU-foil.
In yet another embodiment, the method includes the step of attaching a sole unit to the lower side of the inner shoe. In a further embodiment, the attaching step includes the steps of attaching a midsole to the lower side of the inner
shoe and attaching an outsole to a bottom surface of the midsole. In still a further embodiment, the method includes the step of attaching a support element to the bottom surface of the midsole.
These and other objects, along with advantages and 5 features of the present invention herein disclosed, will become apparent through reference to the following description, the accompanying drawings, and the claims. Furthermore, it is to be understood that the features of the various embodiments described herein are not mutually exclusive 10 and can exist in various combinations and permutations.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings, like reference characters generally refer 15 to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference 20 to the following drawings, in which:
FIG. 1 is a schematic perspective view of a shoe in accordance with an embodiment of the invention;
FIG. 2A is a schematic cross-sectional view of a tool for manufacturing a shell in accordance with the invention; 25
FIGS. 2B and 2C are schematic side views of a medial half-shell and a lateral half-shell manufactured with the tool of FIG. 2A;
FIGS. 3A and 3B are schematic views of a step of a method of manufacturing a shoe in accordance with the 30 invention;
FIGS. 4A and 4B are schematic views of a further step of the method of manufacturing a shoe first depicted in FIGS. 3 A and 3B;
FIGS. 5A and 5B are schematic views of a further step of 35 the method of manufacturing a shoe first depicted in FIGS. 3 A and 3B;
FIGS. 6A and 6B are schematic views of a further step of the method of manufacturing a shoe first depicted in FIGS. 3 A and 3B; 40
FIGS. 7A and 7B are schematic views of a further step of the method of manufacturing a shoe first depicted in FIGS. 3 A and 3B;
FIGS. 8A and 8B are schematic views of a further step of the method of manufacturing a shoe first depicted in FIGS. 45 3 A and 3B; and
FIGS. 9A and 9B are schematic views of a further step of the method of manufacturing a shoe first depicted in FIGS. 3 A and 3B.
DETAILED DESCRIPTION OF THE
Embodiments of the present invention are described below. It is, however, expressly noted that the present 55 invention is not limited to these embodiments, but rather the intention is that variations, modifications, and equivalents that are apparent to the person skilled in the art are also included. In particular, the present invention is not intended to be limited to sports shoes, but rather it is to be understood 60 that the present invention can also be used for any article of footwear or portions thereof. Further, only a left or right upper, sole, and/or shoe is depicted in any given figure; however, it is to be understood that the left and right uppers/soles/shoes are typically mirror images of each other 65 and the description applies to both left and right uppers/ soles/shoes. In certain activities that require different left and
right shoe configurations or performance characteristics, the shoes need not be mirror images of each other.
FIG. 1 shows an overall view of an embodiment of a shoe 1 constructed in accordance with the invention. The shoe 1 includes an upper 15 and a sole unit 10. The shoe upper 15 includes a shell 20 arranged above the sole unit 10. The shoe 1 further includes an inner shoe 30 having an upper side 31 (FIG. 3A) and a lower side 32 (FIG. 3A) arranged inside the shell 20, such that an upper end 19 of the inner shoe 30 projects out of an opening 29 in the plastic shell 20. As shown in FIG. 1, the shell 20 encompasses the upper side 31 of the inner shoe 30. This configuration enables unlimited flexibility of the sole unit 10 and the lower side 32 of the inner shoe 30. The shell 20 provides stability and support to the shoe 1.
In one embodiment, the shell 20 is made from polyurethane (PU), although other plastic materials are contemplated. The three-dimensional shape of the shell 20 is controlled by a blow-molding process. In other embodiments, other methods of processing plastic materials known to a person skilled in the art, for example, foaming of one or more starting materials, can be used to create the desired shape of the shell 20. Alternative materials and manufacturing methods are further described hereinbelow.
FIG. 2A shows one embodiment of a blow-molding tool 40 used in conjunction with a chosen material to create at least a portion of the shell 20. A starting material, for example PU, is inserted as a semi-finished product into a cavity 53 that is defined by an upper plate 50, a lower plate 51, and two side plates 52. The plates 50, 51, 52 collectively form the tool 40. Subsequently, high pressure is applied to press the starting material against the interior walls of the cavity 53. The pressure, in combination with the shape of the cavity 53, results in the shell 20 taking the desired shape, i.e., the shape of the cavity 53. The molding process is typically performed at an elevated temperature, for example, 130° F. to 210° F. The temperature is dependent upon the material used. At an elevated temperature, the starting material is typically soft during the blow-molding process. The final mechanical properties of the shell 20 are obtain after the starting material cools.
As shown, the cavity 53 serves to manufacture only one half of the shell 20. In one embodiment, a lateral half-shell 21 and a medial half-shell 22, as shown in FIGS. 2B and 2C, are produced separately. Subsequently, the lateral half-shell 21 and the medial half-shell 22 are interconnected by, for example, gluing or other interconnection methods. Different materials may be used to manufacture each of the lateral half-shell 21 and the medial half-shell 22. This may be desirable for either technical reasons, if different mechanical properties are desired for the lateral and the medial sides, or for design reasons. Alternatively, the complete shell 20 can be manufactured as a single continuous part. In addition, an individual or plurality of structures 23 may selectively influence the flexibility of the lateral half-shell 21 and/or the medial half-shell 22. For example, the structures 23 may be a set of ribs that adds strength to the upper 15. Alternatively or additionally, the structures 23 may serve an esthetic purpose.
Additionally, a piece of foil 54 may be inserted into the cavity 53, such that the foil 54 is in contact on its lower side with the lower plate 51. The foil 54 binds to the formed material during the blow-molding process. The foil 54 may also be made of PU or of a different material that reliably bonds to the blow-molded body during the blow-molding process. The foil 54 improves the outer surface properties of the finished shell 20. Additionally, the foil 54 facilitates the