Method for gluing a vamp to a shell bottom

Abstract

Method for obtaining a shoe characterized by comprising the following steps : - putting a vamp on a shaper; - fixing the shaper to a lid; - positioning a first and a second upper movable part above the lid so that said two upper movable parts come into contact with the vamp; - insert inside a seat of a plate a shell previously molded with a tread and a perimeter edge projecting with respect to the tread; - overlapping the plate with a first and a second lower movable part defining the seat with the plate; - pouring or injecting a polyurethane into the shell; - overlapping the plate and the lower movable parts with the lid, the upper movable parts and the shoe shaper with vamp, the vamp being therefore in contact with the polyurethane in the shell. - gluing the polyurethane inside the shell with the vamp.

Description

[0001] "Method for gluing a vamp to a shell bottom"

[0002] DESCRIPTION

[0003] Technical field

[0004] The present invention relates to the shoe sector and more speci fically it concerns a method for obtaining a shoe in which the gluing of a shell to a vamp takes place by means of a polyurethane ( PU) pouring and relative mold for obtaining the shoe .

[0005] State of the art

[0006] In the state of the art in the shoe sector it is known that the gluing between soles in polymeric material and vamps takes place by means of a polyurethane pouring / inj ection which turns out to be a visible aesthetic part of the sole of the shoe itsel f with all the quality and wear limitations that this entails .

[0007] Furthermore , once extracted from the mold, the product has some technical burrs necessary for the passage of air that the polyurethane needs to fill the mold cavity . This makes a further trimming activity necessary .

[0008] There is also the possibility of the presence of bubbles due to the entrapment of air inside the polyurethane . P4012PC00

[0009] To make the state of the art procedure feasible , the molds used to allow the extraction of the product are made up of several moving parts .

[0010] These mobile elements come into contact with the polyurethane leaving marks intended as closing lines which remain visible and cannot be removed .

[0011] The mold known to the state of the art comprises the following parts :

[0012] - a plate and a lid for molding the tread

[0013] - two movable elements for closing the plate to be positioned respectively on a first side and a second side of the plate itsel f .

[0014] Going into more detail , the known process comprises the following steps :

[0015] - inj ection inside a plate of thermoplastic polyurethane or rubber and closure of the plate itsel f by means of a lid in order to print a tread of the shoe ;

[0016] - removal of said lid necessary for tread molding;

[0017] - positioning a last a shaper comprising a vamp mounted thereon above the molded tread and placed inside the plate ;

[0018] - positioning on a first side and on a second side of the plate a first and a second movable element bringing the sides of said movable elements into abutment ;

[0019] - polyurethane inj ection to proceed with the molding of a raised edge with respect to the tread and which has the function of gluing the vamp to the tread . P4012PC00

[0020] As an alternative to the first inj ection of thermoplastic polyurethane , the known method provides that the tread is previously molded and then loaded inside the plate , provided however that the tread still has lateral burrs as their presence is necessary to prevent that with the subsequent inj ection, the two materials do not contaminate each other by mixing .

[0021] As visible in figure 15 , the drawbacks that arise are :

[0022] - the presence o f burr on the tread due to the molding of the tread itsel f , burr which therefore requires trimming;

[0023] - the presence of a visible sign of the inj ection point of the polyurethane on the tread;

[0024] - the presence of j oint marks left by the moving components of the mould;

[0025] - the presence of any air bubbles in the visible areas inside the PU pouring / inj ection .

[0026] At the state of the art the following patent applications are known :

[0027] - US 2002 / 170650 Al which discloses a method for making a shoe in which a sole is attached to an upper, having a bottom portion defining an insole , by means of a cover strip which is to be arranged between and which is to interconnect said sole with said insole . The space between the sole , the insole and the cover strip defines an internal cavity which is filled with a foamable material to form a foamed midsole which connects the sole , the insole and the cover strip . P4012PC00

[0028] - US 2019 / 0239596 Al which discloses an article of footwear that has an upper directly attached to the sole , wherein the sole has a film that extends along the lateral walls of the sole to an edge of the film which is before the lateral wall and the superior j unction . The method of manufacturing the article of footwear comprises the steps of placing a film over a mold cavity and then attaching the film to the mold . The film is heated and then drawn into the vacuum mold cavity . The film forms a lining of the mold cavity . A foam composition is inj ected into the lined mold cavity . As the foam composition expands , it interacts with and mechanically engages the upper, which is positioned at the mold cavity to allow for the mechanical engagement which results in direct attachment of the sole to the upper . The film is then cut from the sidewalls of the sole .

[0029] The disadvantages of the above patent applications are as follows :

[0030] - as regards the first patent application, a double manual loading of both the insole and the perimeter strip is required inside a mold which must be specially shaped so that the strip, once loaded in its seat , abuts against the sole as i f this were not done correctly the inj ection of the foam would not form a closure between the covering band and the sole . P4012PC00 as regards the second patent application, the foam composition is not entirely contained in the cavity as it is externally visible between the edge of the upper and the edge of the film that covers the sole , resulting in the need to resort to trimming of excess material together with the other disadvantages mentioned above and visible in figure 15 .

[0031] Objects and abstract of the invention

[0032] The obj ect of the present invention is to obtain a shell glued to the vamp by means of a polyurethane pouring / in ection . Another obj ect of the present invention is to ensure that the polyurethane has the function of adhesive between the vamp and the shell but also of reinforcement between said two materials and without being visible from the outside .

[0033] Another obj ect of the present invention is to ensure that the polyurethane pouring / inj ection remains between the shell and the vamp, avoiding burrs and aesthetic defects of the polyurethane .

[0034] Another obj ect o f the present invention is to eliminate the presence of closure marks caused by the moving parts of the mould .

[0035] These obj ects are achieved by a method comprising the following steps :

[0036] - putting a vamp on a shaper ; fixing the shaper to a lid; P4012PC00

[0037] - positioning a first upper movable part and a secondupper movable part above the lid so that by means of a pressure , said two upper movable parts come into contact with the vamp ;

[0038] - insert inside a seat of a plate a shell previously molded outside said seat , with a tread and a perimeter edge proj ecting with respect to the tread;

[0039] - overlapping the plate with a first lower movable part and a second lower movable part defining the seat with the plate ;

[0040] - pouring or inj ecting a polyurethane into the shell ;

[0041] - overlapping the plate and the lower movable parts with the lid, the upper movable parts and the shaper with vamp, the vamp being therefore in contact with the polyurethane in the shell .

[0042] - gluing the polyurethane inside the shell with the vamp . Preferably the shell is made of thermoplastic polyurethane but it could also be made of rubber or any other thermoplastic material such as for example TR, TPR, TPE .

[0043] The terms upper, lower refer to the overlapping of the various parts constituting the mold of FIG . 5 .

[0044] For greater clarity, it should be speci fied that what is depicted in FIG . 2 must be rotated by 180 ° with respect to the Y axis to allow overlapping with the two upper mobile parts and the plate as shown in FIG . 5 . P4012PC00

[0045] As upper part of a shoe is to be understood by vamp and when said vamp does not completely cover the foot or is cut out with large slits , the shoe is to be considered as a sandal . In the case of a sandal , the vamp can be considered a band or a plurality of bands . In addition to a sandal , the term shoe also refers to a boot .

[0046] As shell is meant a body comprising at the same time a tread surface and a raised edge with respect to the tread surface . The shell is therefore di f ferent from the tread known to the state of the art in that the latter comprises only the tread surface .

[0047] Brief description of the drawings

[0048] Further characteristics and advantages of the invention will result from the description of a preferred but not exclusive embodiment of a method for obtaining a shoe in which the gluing of a thermoplastic polyurethane ( TPU) shell to a vamp takes place by means of a pouring of polyurethane ( PU) , of the mold used and of the directly obtained product which is the subj ect of this patent application, illustrated by way of example but not limitation in the drawing units in which :

[0049] - figure 1 is an axonometric view of a lid 1 of a mold on which a shaper is mounted including an vamp 2 mounted thereon;

[0050] - figure 2 is an axonometric view of the lid 1 with the shaper including the vamp 2 on which the two upper movable parts 3a, 3b are positioned and locked; P4012PC00 figure 3 is an axonometric view of a plate 4 , containing a

[0051] TPU shell 6 , on which the two lower movable parts 5a, 5b are positioned;

[0052] - figure 4 is an axonometric view of the plate 4 with the lower moving parts 5a, 5b and the TPU shell 6 in which the polyurethane 7 is poured .

[0053] - figure 5 is an axonometric view of what is depicted in figure 2 superimposed on the whole of figure 4 , making sure that the two upper movable parts 3a, 3b contact the two lower movable parts 5a, 5b ;

[0054] - figure 6 is a sectional view of the shaper including the vamp 2 and the TPU shell 6 to highlight that the latter is made with a lip that is more open than in the final position so that it is approached to the last by means of the two upper movable parts ;

[0055] - figure 7 is a top view and sectioned according to the section line A-A of the finished shoe ;

[0056] - figure 8 is an axonometric view of the finished shoe with the TPU shell 6 glued to the vamp by means of the PU pouring 7 ;

[0057] - figures 9 - 15 show the steps for obtaining a shoe by means of a mold and a gluing process known in the state o f the art .

[0058] Detailed description of the invention

[0059] According to a preferred - but not limiting - embodiment , the present invention relates to a method for bonding a vamp of a P4012PC00 shoe with a shell by means of a polyurethane ( PU) pouring . The present invention also relates to a mold for obtaining a shoe . Preferably, the shell is made of thermoplastic polyurethane ( TPU) but could also be made of rubber or any other thermoplastic material such as TR, TPR, TPE . The mold, which is the subj ect of this patent application, includes :

[0060] - a lid 1 ;

[0061] - a first and a second upper movable part 3a, 3b ;

[0062] - a first and a second lower movable part 5a, 5b ;

[0063] - a plate 4 .

[0064] In the figures , with :

[0065] - 2 denotes a shoe mold including a vamp on which a main X axis extending from a forefoot area to a heel area, a secondary Y axis perpendicular to the main X axis , and a Z axis perpendicular to the plane delineated by the X-Y axes are defined;

[0066] - l a lid of the mold comprising :

[0067] - a first surface la

[0068] - a second surface lb parallel to said first surface la and including a seat 1c suitable for receiving the shaper with vamp 2 ;

[0069] - a first and second protrusion Id, le proj ecting from said second surface lb suitable for clamping along the main axis X the shaper with vamp 2 ;

[0070] - 3a, 3b a first and a second upper movable part comprising respectively : P4012PC00 a first surface 3a1, 3b1a second surface 3a11, 3b11parallel to said first surface 3a1, 3b1

[0071] - a first and second protrusion 3a111, 3b111pro j ecting from the first surface 3a1, 3b1and capable of contacting the first and second protrusion Id, le of lid 1 . a first and second recess 3aIV, 3bIVsuitable for receiving a portion of the extrados and intrados with respect to the X-axis of the shaper 2 ;

[0072] - 4 a plate comprising a seat 4a able to receive a shell ;

[0073] - 5a, 5b a first and a second lower movable part including a first and a second recess 5a1, 5b1respectively able to receive a portion of the extrados and intrados with respect to the X axis of the shell 6 ;

[0074] - 7 a polyurethane pouring / inj ection .

[0075] The two upper movable parts 3a, 3b have a shape coupling with the lid 1 j ust as the two lower movable parts 5a, 5b have a shape coupling with the plate 4 .

[0076] The complete mold provides for the overlapping in order starting from the bottom of the plate 4 , of the two lower movable parts 5a, 5b, of the two upper movable parts 3a, 3b and finally of the lid 1 .

[0077] The method obj ect of the present patent application consists in fitting a vamp on a shaper and fixing a shaper to a lid 1 of a mould . The two upper movable parts 3a, 3b are then positioned on the two protrusions Id, le of the lid 1 , taking P4012PC00 care , by means of a slight pressure , that they come into contact with the vamp .

[0078] The next step is to insert a previously molded shell 6 inside the seat 4a of the plate 4 and superimpose the two lower movable parts 5b, 5b on the plate 4 . As shell 6 is meant a body comprising at the same time a tread surface and a raised edge with respect to the tread surface .

[0079] I f the shell 6 had protruding geometries on the raised edge , the loading would still be permitted since both the upper and lower movable elements are divided into two parts and are not a single body .

[0080] The polyurethane 7 is then poured into the shell 6 .

[0081] The optimal quantity of polyurethane to be pour is poured using a 3D mathematical model through which the weight of the polyurethane to be inj ected is obtained, said weight being defined by the ratio between volume and density ( speci fic weight ) of the same . The weight of the PU to be inj ected varies according to the number of the shoe and using the above 3D mathematical model it is possible to calculate the exact quantity to be inj ected so that it does not come out when the shell 6 is glued to the vamp .

[0082] Once the PU has been poured into the shell 6 , the plate 4 and the two lower movable parts 5a, 5b are closed by superimposing the lid 1 and the two upper movable parts 3a, 3b and the shaper with vamp 2 on them . In this way the polyurethane 7 adheres to the vamp . P4012PC00

[0083] Figure 6 shows the shaper in section including the vamp 2 and the shell 6 . In said figure it is visible that the shaper with vamp 2 sinks inside the shell 6 for a certain thickness of the shell 6 itsel f , the remaining part thickness of the shell 6 is filled with polyurethane 7 .

[0084] The shell 6 is made with a lip 8 that is more open than the final position so that when the two upper mobile parts 3a, 3b, fixed on the lid 1 , are brought closer to the vamp, the lip 8 bends inwards and therefore towards the shaper with vamp 2 j ust enough to guarantee filling and non-leakage of the PU 7 from the shell 6 . To ensure that this occurs , the l ip 8 of the shell 6 is printed more open than the final position . The shape of the lip 8 can be any, the important thing is that during the pressure of the two upper movable parts 3a, 3b towards the shaper with vamp 2 , the lip 8 is able to rotate towards said shaper 2 .

[0085] The sinking of the shaper including the vamp 2 inside the shell 6 is even better visible in the section of figure 7 . Again in figure 7 the thickness of the polyurethane 7 is visible j ust as it is visible that the lip 8 contacts the vamp of the shoe . The present method provides the advantage that in order to glue the vamp with the shell it is not necessary to pour a PU which is visible from the outside . This has been made possible because , di f ferently from the alternative form known to the state of the art , it is not only a tread that i s loaded inside a plate but a tread including a raised edge and therefore a P4012PC00 shell . With the mold known to the state of the art this would not have been possible .

[0086] The materials and dimensions of the invention as described above , illustrated in the attached drawings and claimed hereinafter, may be any according to requirements . Furthermore , all the details and mechanisms of the mold can be replaced with other technically equivalent ones , without thereby departing from the protective scope of the present patent application .

[0087] Furthermore , in order to speed up the creation of di fferent shoe models , an identi fication code is present on each mold, such as a serial number, an alphanumeric indication of the name , model and shoe number, etc . and a pouring machine comprises an electronic control unit programmed to receive the identi fication code as input and to store a reference table in which, on the basis of the code , the corresponding dosed quantity is stored, e . g . by weight or by volume , of the polyurethane suitable to make sure that , once the volume free from the mathematical model is known, the level of the polyurethane 7 reaches but does not exceed the lip 8 . In this way, unwanted leakage of polyurethane 7 beyond the lip 8 is avoided from shell 6 .

Claims

P4012PC00CLAIMS1. Method for obtaining a shoe characterized by comprising the following steps:- putting a vamp on a shaper;- fixing the shaper to a lid (1) ;- positioning a first upper movable part and a second upper movable part (3a, 3b) above the lid (1) so that by means of a pressure, said two upper movable parts (3a, 3b) come into contact with the vamp;- insert inside a seat (4a) of a plate (4) a shell (6) , previously molded outside said seat (4a) with a tread and a perimeter edge projecting with respect to the tread;- overlapping the plate (4) with a first lower movable part and a second lower movable part (5a, 5b) defining the seat (4a) with the plate (4) ;- pouring or injecting a polyurethane (7) into the shell (6) ;- overlapping the plate (4) and the lower movable parts (5a, 5b) with the lid (1) , the upper movable parts (3a, 3b) and the shoe shaper with vamp (2) , the vamp being therefore in contact with the polyurethane (7) in the shell (6) .- gluing the polyurethane (7) inside the shell (6) with the vamp .

2. Method according to claim 1, wherein the shell (6) is made of thermoplastic polyurethane or rubber.

3. Method according to claim 1, wherein the attachment of the shaper (2) to the lid (1) takes place by means of releasableP4012PC00 attachment of the shaper with the vamp (2) in a seat (1c) of the lid ( 1 ) .

4. Method according to claim 1, wherein the shell (6) comprises a lip (8) carried by the edge and configured to adhere to the vamp when the upper movable parts (3a, 3b) are overlapped on the lid (1) and are subject to mutual pressure.

5. Method according to claim 4, wherein the pouring step comprises the step of dosing the polyurethane (7) in an amount such that, after the overlapping step, the polyurethane (7) reaches without exceeding the lip (8) .

6. Method according to claim 1, wherein the upper movable parts (3a, 3b) and the lower movable parts (5a, 5b) are opposite each other with respect to an X axis extending from a forefoot region to a heel region and they allow the loading of any type of shell (6) .

7. Method according to claim 5, characterized in that said dosing step comprises the step of reading an identification code of a mold and selecting from a table a dosed quantity of polyurethane (7) to be poured into the shell (6) on the base of the identification code.

8. Mold characterized by comprising:- a lid (1) configured to releasably connect with a shoe shaper (2) on which a vamp is fitted;- a first and a second upper movable part (3a, 3b) configured in use to contact the vamp;- a first and a second lower movable part (5a, 5b) configuredP4012PC00 in use to define a seat (4a) of a plate (4) ;- the plate (4) comprising the seat (4a) adapted in use to receive the shell (6) and defined in part by the first and second lower movable parts (5a, 5b) .

9. Mold according to claim 6, wherein the two upper movable parts (3a, 3b) have a form coupling with the lid (1) and the two lower movable parts (5a, 5b) have a form coupling with the plate ( 4 ) .

10. Footwear obtained by the method according to claims 1-6 and the mold according to claims 7-9 wherein the polyurethane (7) is placed inside the shell (6) and remains between the shell (6) and the shoe shaper with the vamp (2) causing their gluing .

11. Method according to claim 7 wherein the polyurethane is poured.

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