Method for obtaining a shoe, and shoe obtained with said method

Abstract: The method for obtaining a shoe entails the execution of a nonrigid sock or upper (1), which is tensioned by means of an adapted last to allow the coupling thereto of an intermediate member (2) on which multiple through holes (6) are formed and which has an optional cavity at the arch region. Then the intermediate member is placed inside a mold and at least one first injection or pouring of preferably but not necessarily compact thermoplastic or thermosetting or expandable material is performed, so as to affect at least the intermediate structural element to obtain a semifinished item below which a sole is associable.

Description: The present invention relates to a method for obtaining a shoe and to a shoe obtained with said method. Conventional sports shoes, for example for mountaineering, are produced by using a nonrigid sock to which an upper, open at the bottom, is coupled perimetrically and in an upward region by stitching. The upper is in fact subsequently placed at a last, and its ends are turned over on an adapted insole and are stitched or glued thereto to obtain a closed configuration that is adapted to fully surround the nonrigid sock. A sole provided with a tread is then coupled below the upper by injection-molding or stitching. EP 0 152 783 discloses a flat sole that has a box-like shape in the region of the toe and a counter in the heel region; these parts are connected by lateral walls and the sole comprises selective support means that are associated with the sole and are adapted to vary its flexibility. The sole and its components are then stitched or glued to the upper. US-4,706,316 discloses a method for producing shoes that entails, in this case too, the production of separate components that can be mutually associated to obtain the upper, to which a sole is subsequently glued. Both of the described solutions in any case have a member that is provided with counters for the heel and for the toe and is stitched or glued to the upper together with the other components of the shoe. This conventional method allows a simplified assembly, because the unit constituted by the member and by the nonrigid sock acts as a semifinished item on which various components are then fitted. Several manual stages are, however, still required. This conventional method also entails stitches or gluing operations for mutually associating the various components. Furthermore, the manual nature of the described operations does not ensure constant quality of the finished product, since this depends on the skill of the operator. It is also noted that the external stitches considerably reduce the waterproofing of the shoe. Furthermore, the cost of the assembly operations is high, and this accordingly causes a high cost of the finished product. FR-2208279 discloses a method for manufacturing a shoe including molding a plastic material on a semifinished item constituted by an upper connected to a sole member. A problem connected with this method is that the upper has to be firmly associated with the sole member before molding. Last, WO 94/15493 describes a process for manufacturing a shoe wherein an upper, open at the bottom, is joined to an intermediate member by means of a stitching. The aim of the present invention is to solve the described technical problems, eliminating the drawbacks of the mentioned prior art by providing a highly industrializable method that accordingly allows to obtain a shoe while limiting the number of manual assembly stages. Within the scope of the above aim, an important object is to provide a method that allows to drastically reduce the quantity and areas affected by stitches. Another important object is to provide a method that allows to obtain shoes that have a high and constant quality. Another important object is to provide a method that allows to obtain shoes that have excellent waterproof and comfort characteristics for the user. Another object is to provide a shoe that is reliable and safe in use and can be obtained with ordinary machines and facilities. This aim, these objects, and others which will become apparent hereinafter are achieved by a method for producing a shoe according to the appended claims. Further characteristics and advantages will become apparent from the detailed description of a particular but not exclusive embodiment, illustrated only by way of non-limitative example in the accompanying drawings, wherein: figure 1 is a side view of the nonrigid sock, with which the intermediate member is associated; figure 2 is a view, similar to the preceding one, of the semifinished item; figure 3 is a view, similar to the preceding one, of the application, below the semifinished item, of a sole that is constituted by two treads that are associated in the heel and metatarsal region of the semifinished item; figure 4 is a side view of the shoe obtained according to the invention; figure 5 is a side sectional view, taken along the longitudinal median plane of the shoe according to a further aspect of the invention; figure 6 is a view, similar to figure 5, of still a further embodiment of the invention; figure 7 is a view, similar to the preceding one, of still a further embodiment of the invention. With reference to the above figures, a nonrigid sock or an upper, generally designated by the reference numeral 1, has an adapted insole, not shown, and an upper externally associated. The nonrigid sock or upper 1 is then arranged inside an adapted last, not shown, to tension the upper so as to achieve good adhesion perimetrically with respect to the last. Then, an intermediate member 2 is dry-coupled to the nonrigid sock or upper 1 and affects the lower region 3 of the upper as well as the heel region 4 and/or the toe region 5, which are connected to each other. A plurality of first holes 6 are formed at the lateral surface of intermediate member 2. The holes are preferably formed at the heel region 4 and at the toe region 5. Intermediate member 2 can also have, at the plantar arch region 7, a protrusion 8 that protrudes beyond the lower edge 9 of intermediate member 2. Protrusion 8 forms a cavity 10. The method then entails placing the intermediate member 2 inside a mold and performing at least one first injection or casting of preferably but not necessarily compact thermoplastic or thermosetting or expandable material, such as single- or multiple-component polyurethane, which overlaps at least at the intermediate member 2. In a preferred embodiment it is used a bi-component expandable polyurethane injected and subsequently expanded inside the mold. A semifinished item is thus produced, generally designated by the reference numeral 11, in which an optimum coupling to the nonrigid sock or upper 1 is achieved, since the thermosetting or thermoplastic or expandable material has penetrated at the holes 6 formed on the intermediate member 2, also, as shown in figure 2, affecting part of the surface that is adjacent to the heel region 4 and the toe region 5 of said nonrigid sock or upper 1. The semifinished item 11 thus obtained has no stitches of any kind, forming a waterproof barrier in the lateral and lower regions of the nonrigid sock or upper 1 and thus in areas that are in direct contact with water during walking. A sole or any other sole member, such as a roller skate for example, can be coupled below the semifinished item 11, by means of conventional methods, such as gluing, or by means of the same or of a second injection of foamed thermoplastic material or of expandable material, as better explained hereinafter; in the particular solution shown in figure 3, said sole is constituted by two treads 12a and 12b that are coupled at the heel and toe regions. To increase user comfort, one or more blocks, having the desired flexibility characteristics, may be inserted in cavity 10. It has thus been observed that the invention has achieved the intended aim and objects, since it allows greater industrialization for the production of the shoe, limiting the number of manual assembly stages and limiting the stitches only to the nonrigid sock or upper or, possibly, only to the coupling of the upper to the nonrigid sock; moreover, this occurs in regions that are not in direct contact with, or in the vicinity of, the ground during walking. Optimum waterproofing of the shoe is therefore also allowed, whereas the possibility of inserting adapted inserts in the cavity 10 allows to further improve user comfort. The inserts in fact act as shock-absorbing elements in a particularly sensitive region such as the plantar arch region. An important feature of the method according to the invention is that intermediate member 2 can be coupled to the upper without glue or any other means because its particular shape allows it to remain in position, during the injection-molding. The method is of course susceptible of numerous modifications and variations, all of which are within the scope of the same inventive concept. Thus, for example, figure 5 illustrates a nonrigid sock or upper 101 that is dry-coupled to an intermediate member 102 provided with adapted second holes 113 that are formed at the region of the sole of the foot and optionally at the heel region 104 and at the toe region 105. In this embodiment, the intermediate member 102 thus obtained is placed inside a mold to perform a first injection or pouring of preferably but not necessarily compact thermoplastic or thermosetting or expandable material that affects at least said intermediate member 102 and therefore, in addition to the first holes, also affects the second holes 113, so as to facilitate the penetration of the thermoplastic or thermosetting or expandable material in direct contact with the nonrigid sock or upper 101 until it practically surrounds the foot except for the region in which the cavity 110 is formed. It is also subsequently possible to apply the additional phases described above, and therefore the coupling of a tread 112a and 112b with the optional interposition at the semifinished item 111 of flexible material, such as a foamed or an expandable polyurethane, designated by the reference numeral 114, by means of a second injection. Flexible material 114 thus allows to cushion impacts during walking, increasing the comfort of the user. In another embodiment, shown in figures 6 and 7, the process entails, after obtaining the semifinished item 211, the removal, for example by cutting, of one or more walls 215 that form the cavity 210. The semifinished item 211 is then arranged inside a mold to perform a second injection of flexible material, such as for example foamed or expandable polyurethane, designated by the reference numeral 214, which affects not only the lower regions of the heel and of the toe but also the cavity 210; this is done to further increase the user comfort. Then, by means of a gluing operation, or prior to the second injection, it is possible to apply the treads 212a and 212b below the flexible material 214. In the second case, the injection of flexible material 214 rigidly couples treads 212a and 212b to semifinished item 211. In these solutions, too, the method is highly industrialized, with considerable limitation of manual operations, and this allows to achieve a high reduction in production costs, both by virtue of the mechanization of many operations and by virtue of the lower use of expendable materials, such as adhesives and small metal parts, required in the prior art methods for connecting the various components. The finished product also has a high quality level which is constant in time. Furthermore, precise and infinitely repeatable anatomical shapes can be obtained. The considerable reduction of the number of stitches is extremely important. None of the stitches is visible, at least in the lateral and lower regions that are adjacent to the sole and in contact with the ground, since they are embedded in the thermoplastic or thermosetting or expandable material during injection or pouring. A reduction in the number of manual operations also leads to optimal waterproofing of the shoe and good warmth thereof, since there is no discontinuity on the outer surface of the upper, as it happens in conventional shoes because of the stitch holes. The user comfort is considerably improved, because the materials used for the intermediate member and for the subsequent injections or castings are not in direct contact with the foot and are located outside the nonrigid sock or upper. The materials may of course also be the most suitable according to the specific requirements. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims: A method of manufacturing a shoe, comprising the following steps: a) providing an assembly that includes an upper (1, 101) and an insole attached thereto, which form a non-rigid sock; b) arranging said assembly on a last and tensioning it; c) providing an intermediate member (2, 102) consisting of a toe portion and a heel portion connected by a central portion, having respective peripheral upright edges that define lateral surfaces of the intermediate member which thus has a substantially concave shape; d) coupling the assembly mounted on the last to the intermediate member, by fitting the former into the latter; e) connecting the assembly to the intermediate member by carrying out a casting or injection molding of plastic material into a mold where the intermediate member is arranged, so that the plastic material overlaps at least the intermediate member and thereby obtaining a semifinished shoe item (11, 111, 211); f) attaching a sole member (12,112,212) to the semifinished shoe item thereby achieving the shoe. A method according to claim 1, wherein the plastic material is a thermoplastic or thermosetting expandable material. A method according to claim 2, wherein the plastic material is a single or multiple component polyurethane. A method according to any preceding claim, wherein a plurality of first and second holes (6, 113) is formed in the lateral and lower surfaces of the intermediate member (2, 102) at said heel and toe portions, through which the plastic material penetrates during said casting or injection molding phase thereof. A method according to any preceding claim, wherein said intermediate member (2) has at least one protrusion at the plantar arch region protruding beyond the lower surface of the intermediate member and forming at least one cavity (10, 110, 210). A method according to claim 5, wherein one ore more blocks having desired flexible characteristics are inserted in said at least one cavity (10, 110, 210). A method according to any preceding claim wherein the sole member (12, 112, 212) is attached to said semifinished shoe item (11, 111, 211) by means of a second injection of foamed or expandable plastic material. A method according to any of claims 5 to 7, wherein the sole member (12, 112, 212) consists of two treads (12a, 12b; 112a, 112b; 212a, 212b) attached to the toe and heel regions of the shoe item. A method according to any of claim 7, wherein one or more walls of said at least one cavity (210) are removed and the sole member (12, 112, 212) is attached to said semifinished shoe item (211), by means of the second injection of foamed or expandable plastic material which fills said at least one cavity. A shoe comprising an upper (1, 101), an intermediate member (2, 102) and a sole member (12, 112, 212), characterized in that : the intermediate member (2, 102) consists of a toe portion and a heel portion connected by a central portion, having respective peripheral uprights edges that define lateral surfaces of the intermediate member (2, 102), and in that the upper (1, 101) with an insole attached thereto is fitted into the intermediate member (2, 102) and connected to it by casted or injected plastic material overlapping at least the intermediate member (2, 102) thereby forming a semifinished shoe item to which the sole member (12, 112, 212) is attached. A shoe according to claim 10, wherein a plurality of first and second holes (6, 113) is formed in the lateral and lower surfaces of the intermediate member (2,102) at the heel and toe portions thereof, through which some of the casted or injected plastic material penetrates.

Inventors: PEROTTO RICCARDO, PRIAROLLO FRANCO, ROMANATO MARIAROSA, PEROTTO, RICCARDO, PRIAROLLO, FRANCO, ROMANATO, MARIAROSA
Applicants: ASOLO SPA, ASOLO S.P.A.
Application year: 1996
Main classification: B29D31
IPC codes: A43B13, A43B9, B29D35