EP2155011A1

EP2155011A1 - Method and plant for joining two parts of an item of footwear

Info

Publication number: EP2155011A1
Application number: EP08737398A
Authority: EP
Inventors: Raffaele Saurwein
Original assignee: ALC Flenco Group Srl
Current assignee: ALC Flenco Group Srl
Priority date: 2007-04-10
Filing date: 2008-04-09
Publication date: 2010-02-24
Also published as: ITTO20070315A1; WO2008122874A8; WO2008122874A1

Abstract

Method and plant (1) for connecting a sole (3) to an upper (4) of an item of footwear, whereby a solid uniform layer (20) of gluing material is spread only on one between the sole (3) and the upper (4) before coupling and forcing the sole (3) and the upper (4) against one another by means of at least two opposed inflatable cushions (37) (50) defining between them a variable- volume chamber for housing and support of the upper-sole ensemble (B); upon reaching of a condition of maximum forcing, the gluing material being brought to a liquid phase and then cooled and brought to the solid phase before interrupting forcing and extracting the upper-sole ensemble (B) from the variable- volume chamber.

Description

"METHOD AND PLANT FOR JOINING TWO PARTS OF AN ITEM OF FOOTWEAR"

TECHNICAL FIELD The present invention relates to a method for joining two parts of an item of footwear.

In particular, the present invention relates to a method for joining a sole to an upper, to which the ensuing treatment will make explicit reference without this implying any loss of generality.

BACKGROUND ART

In the field of footwear, in general, it is known to join the sole to the upper via the interposition of a gluing material . For said purpose, the upper, set on a corresponding shaped forming body, and the sole are fed through a station for depositing glue, in which deposited on the upper and on the sole are respective layers of gluing material of the solvent type. Before setting the sole on the upper both of the layers of gluing material deposited are activated by exposing them to a source of heat, conveniently an electrical resistor. When activation is completed, the sole is then manually superimposed on the upper, after which the sole and the upper are pressed against one another in mechanical presses until a complete adhesion of the two layers of gluing material is obtained. Since the sole, but also the upper, have shape memories and the surfaces on which the gluing material is spread may not be perfectly plane, pressing normally requires exertion of high thrusts that inevitably are at least in part transferred also onto parts of the upper different from the ones in contact with the sole, with the result that, in order to prevent tearing or forms of permanent deformation of the upper, the latter must be adequately sized and often oversized with respect to the resistance required by normal use of the item of footwear. Once again following upon pressing, owing to the fact that the support of the upper is rigidly connected to a fixed attachment body, on the support itself at each pressing operation concentrated stresses are . generated, which lead to partial failure of the support itself in a short time.

Finally, following upon the step of deposition of the gluing material on the upper, precisely on account of the constructional characteristics of the upper itself, it often becomes necessary to carry out a so-called "levelling" operation to guarantee contact between the two layers of glue throughout the sole-upper interface.

Even though forming modality just described is used, it proves far from satisfactory in so far in order to obtain footwear having a high degree of quality and finish and a substantial invariance of said degree of quality it is necessary to resort to skilled staff. It is in fact essential to deposit the exact amount of gluing material and set the latter inside pre-set perimeters or areas to prevent undesirable dripping following upon pressing and indispensable subsequent cleaning operations, just as likewise indispensable is setting the sole in a pre-set position on the upper.

In addition to what has been set forth above, the mode of production described and the use of solvent gluing materials entail, both during connection of the sole to the upper and when the connection has been completed, the production of unpleasant fumes and the presence of toxic substances, which, even though they are cleaned off at the end of forming, cannot in any case be removed completely and are hence inevitably transferred to the user during use of the item of footwear with foreseeable consequences.

DISCLOSURE OF INVENTION The aim of the present invention is to provide a method for joining two parts of an item of footwear that will enable the problems set forth above to be solved in a simple and inexpensive way, and, at the same time, to provide high- quality footwear with constant shape operating in the substantial absence of unpleasant and noxious emissions.

Provided according to the present invention is a method for connecting a sole element to an upper of an item of footwear; the method comprising the steps of setting a gluing material between the sole element and the upper, coupling the sole element and said upper to one another, and exerting an action of pressing of the sole element and of the upper against one another; said method being characterized in that the interposition of the gluing material comprises the steps of setting at least one layer of substantially solid gluing material only on one between said sole element and said upper, and in that said action of pressing is carried out using first ^"and second opposed inflatable cushion means.

Preferably, in the method defined above, the layer of gluing material is deposited only on top of the sole element.

The present invention moreover relates to a plant for connecting a sole element to an upper of an item of footwear.

Provided according to the present invention is a plant for connecting a sole element to an upper of an item of footwear, the plant comprising supply means for setting a gluing material between the sole element and the upper, and forcing means for exerting an action of pressing of the sole element and of the upper against one another; said item of footwear being characterized in that said supply means comprise forming means for forming at least one layer of substantially solid gluing material only on one between said sole element and said upper, and in that said pressure means comprise first and second opposed inflatable cushion means .

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the attached figures, which illustrate a non-limiting example of embodiment thereof, and in which:

Figure 1 is a schematic illustration substantially in the form of block diagram of an intermediate portion of a preferred embodiment of the plant for joining two parts of an item of footwear provided according to the teachings of the present invention;

Figure 2 illustrates, in side elevation and at an enlarged scale, a detail of. the plant of Figure 1;

Figure 3 is a schematic illustration in side elevation of an initial portion of the plant of Figure 1;

Figure 4 is a view at a markedly enlarged scale according to the arrows IV of Figure 3 ; and

Figure 5 is an illustration at a markedly enlarged scale of a detail of Figure 1.

BEST MODE FOR CARRYING OUT THE INVENTION

In Figures 1 and 3, designated as a whole by 1 is a plant for joining two parts of an item of footwear, and, in particular, a plant for joining a sole 3 of any thickness to an upper 4 of an item of footwear, designated as a whole by 5 (Figures 1, 2 and 5) .

The plant 1 comprises a unit 6 for preparation of the sole 3 , a station 7 for loading the upper 4, a station 8 for laying the sole 3 on the upper 4, an intermediate area 9 for pressing and joining the sole 3 to the upper 4, a cooling station 10, and a station 10' for unloading the sole-upper ensemble B thus made.

With reference to Figure 3, the unit 6 comprises a resting surface 11 for a tape 12 made of plastic or paper material, preferably siliconed paper, having an adhesiveness lower than that of the sole 3 and forming part of a reel 13 to be unwound carried by a fixed support (not illustrated) . - The unit 6 moreover comprises a motor-driven rewinder device 18 for 5. drawing the tape 12 in contact with the resting surface 11 in a rectilinear direction 14, and around an edge 15 of an arrow- shaped fixed deflector element 16 set downstream of the surface 11 in the direction of feed of the tape 12 and upstream of the rewinder 18. Provided in the proximity of an0 input area of the resting surface 11 is a dispenser assembly 19, designed to dispense continuously a gluing material, preferably a polyurethane material of the thermohygroreactive type. The dispenser assembly 19 is shaped so as to deposit on a top surface of the tape 12 a continuous layer 20 of adhesive5 material having a pre-set thickness S, which ranges, according to the particular application and/or the thickness of the sole, conveniently between 0.1 and 10 mm, and a width greater than (Figure 4) or at the limit equal to the maximum width of the sole 3 itself. 0

Set downstream of the dispenser assembly 19 in the direction of feed of the tape 12 and on top of the resting surface 11 is a pressure roller 22 parallel to the surface and set at a distance D from the surface smaller than the sum of the5 thicknesses of the layer 20 and of the sole 3. Wound on the roller 22 is an intermediate portion of a tape 23 unwound off a reel 24 and rewound on a rewinder head 25 after having been deviated by a roller 26 parallel to the roller 22 and set at a distance from the surface 11 equal to that of the roller 220 itself.

At output from the unit 6, the soles 3 proceed towards an intermediate magazine or storage unit (not illustrated) , or else proceed directly towards the station 8 traversing, when5 required, an edging station 27. Housed in the station 27 is an abrasive assembly 28, in itself known, designed to remove a perimetral portion of gluing material present on the sole 3.

The stations 7, 8, 10, 10' and the area 9 are traversed by a delivery branch 29 of a conveyor 30, -which forms part of the plant 1 and a belt 30' of which is wound in an endless loop around two deflector rollers 31, one of which is motor-driven to cause advance of the belt 30' in a counterclockwise direction as viewed in Figure 1. The belt 30' carries fixedly connected thereto a plurality of fixed radial pins 32 extending in a direction orthogonal to the branch 29 and arranged at a constant pitch P from one another. Each of the pins 32 defines a fixed attachment for a corresponding supporting member 33, in itself known, which carries fitted thereto a corresponding upper 4 and is slidably coupled to the corresponding pin 32 in the station 7. For said purpose, each supporting member 33 is provided with a blind hole 34 slidably engaged by the corresponding pin 32, which carries at one free end thereof a pushbutton 35, a mobile element of which is designed to co-operate with the end of the blind hole 34 for signalling the relative position between the pin 32 and the member 33.

Once again with reference to Figure 1 and, in particular, to Figure 2, each pin 32 is surrounded by a respective inflatable-cushion body 37, an input/output opening 38 of which, extending through the belt 30', is designed to be connected to a chamber 39 supplied with compressed air or other equivalent fluid under pressure during displacement of the delivery branch 29 towards the unloading station 10'.

In addition to the branch 29, the intermediate pressing area 9 is traversed by the delivery branch 43 of a belt 41a of a further conveyor 41 partially set on top of the conveyor 30. The belt 41a is mobile in a clockwise direction as viewed in Figure 1 in a way synchronous with the conveyor 30, is wound in an endless loop around two deflector rollers 42, one of which is motor-driven, which are parallel to one another and to the rollers 31. The delivery branch 43 is partially wound around two deflector rollers 44 parallel to the rollers 42 and set at a distance from the branch 29 smaller than the distance between the rollers 42. In this way, the delivery branch 43 has an intermediate stretch 43a parallel to the branch 29 and set at a pre-defined distance from the branch 29 itself and two end stretches 43b inclined toy a pre-set angle A.

The belt 41a carries fixedly connected to its outer surface a plurality of bell-shaped or cup-shaped bodies 46, which are arranged at the same distance apart from one another at a pitch Pl equal to the pitch P and comprise an end wall 47, fixedly connected to the belt 41a, and a side wall 48, which in the pressing area 9 extends towards the branch 29 and has a free terminal edge 48a of its own set in a position substantially tangential to the branch 29 so as to surround the cushion body 37 completely and define a lateral rest therefor.

According to a variant (not illustrated) , each bell-shaped body 46 is shaped in such a way that its edge 48a extends in a position set at a distance from the branch 29 and the branch 29 itself carries fixedly connected thereto a lateral-resting collar for the cushion body 37, designed to couple the bell- shaped body 46 to define a closed outer casing.

Once again with reference to Figure 2, housed inside each bell-shaped body 46 is a respective inflatable cushion body 50, an input/output opening 50a of which extends through the corresponding wall 47 and the belt 41a and is designed to be connected to a chamber filled with pressurized fluid, conveniently compressed air or other equivalent pressurized fluid, designated as a whole by 51.

Once again with reference to Figure 2, each cushion body 50 houses a corresponding source of heat 52 (Figure 2) , conveniently of the microwave type, which can be activated for heating the gluing material deposited on the sole.

Operation of the plant 1 will now be described with reference to the attached figures considering for simplicity of exposition a single upper 4 and a single sole 3 to be joined together and starting from an instantaneous condition of operation, in which the supporting member 33 with the corresponding upper 4 fitted thereon is set in the station 8 coupled to one of the pins 32 so as to press the pushbutton 35, the corresponding cushion body 37 is in a deflated resting condition, and the layer 20 of gluing material is laid on the stretch of the tape 12 upstream of the pressure roller 22.

Starting from said condition, during translation of the tape 20, the sole 3 is rested on the layer of gluing material upstream of the roller 22, as illustrated in Figures 1 and 4. During feed of the tape 12 in the direction 14, the sole 3 is squeezed by the roller 22 and gripped between the tapes 20 and

23 causing progressive gluing of the gluing material underlying the sole 3 to the sole 3 itself, and of the gluing material outside of the sole 3 to the tape 23; the sole 3, still kept pressed by the tape 23, then advances towards the roller 26, at output from which, on account of the fast deviation of the tape 23 itself in a direction substantially orthogonal to the resting surface 11, the part of gluing material outside the sole 3 abandons the tape 12 to stick to the tape 23, which, as has been said previously, presents an adherence greater than that of the tape 12. As soon as the sole 3 passes beyond the edge 15 of the arrow-shaped element 16, on account of the sharp deviation also of the tape 12, the sole 3 proceeds parallel to the surface 11, whilst the gluing material underlying the sole 3 itself progressively detaches from the tape 12, given that the latter has an adhesiveness lower than that of the sole 3. At this point, the rubber sole 3, i.e., the sole provided with a layer of substantially solid gluing material, when so required, is fed through the edging station 27, in which a perimetral portion of gluing material present on the sole 3 is removed via the tool 28, after which it is fed towards the intermediate storage unit (not illustrated) waiting to be transferred into the station 8 or else is directly transferred into the station 8 itself. Once it has reached the station 8, the sole 3 is positioned on the upper 4 and then pre-connected to the upper 4 itself by means of spot welding using, for example, a heater tool that melts the gluing material locally forming a sole-upper ensemble B. At this point, both of the conveyors 30 and 41 are activated, the belts of which advance . in synchronism determining progressive insertion of the sole-upper ensemble B inside the corresponding bell-shaped body 46. When the edge 48a of the bell-shaped body 46 is set in a position facing the branch 29, the opening 38 of the cushion body 37 comes into communication with the pressurized chamber 39, and then the cushion body 37 is progressively inflated, the supporting member 33 being moved away from the branch 29 until the constraint with the pin 32 is practically cancelled out. The pushbutton 35 at this point issues a command for emission of a signal indicating that uncoupling has occurred and authorizes continuation of the process. Following upon advance of the belts, the opening 50a is brought into communication with the chamber 51, and also the cushion body 50 is progressively inflated, delimiting with the corresponding cushion body 37 a variable-volume seat for housing the upper 4, the corresponding supporting member 33, and the sole 3. Inflation of both of the cushions 37 and 50 proceeds until an inflated operative condition is reached.

During inflation, the volume of the seat decreases progressively, and forcing of the sole 3 against the upper 4 increases proportionally until a maximum pressure is reached, following upon which the source of heat 52 that causes melting of the gluing material is activated. On account of the state of high pressure, the gluing material in the liquid state penetrates within and fills all the gaps present between the sole 3 and the upper 4. Once melting has ceased, the source of heat 52 is de-activated, and the existing state of forcing is maintained during advance of the bell-shaped body 46 through the cooling station 10, in which, for example by means of forced ventilation or via refrigerating plants, the gluing material is again brought to the solid state. In the case of use of hygroreactive polyurethane materials, solidification is also a result of the presence in the gluing material of particles of water, which, during heating, are converted into vapour and diffuse throughout the gluing material transforming it into an unmeltable and tough solid body. As an alternative or in parallel to the particles of water dispersed in the gluing material, passage of the gluing material from the liquid state to the solid state is facilitated by spraying via dispenser nozzles (not illustrated) water on the sole 3 or on the upper 4 or on both, preferably prior to inflation of the cushions 37 and 50.

Once cooling is terminated, the subsequent advance of the belts causes connection of the openings of the cushions 37 and 50 to the discharge, consequent deflation of the cushions 37 and 50 themselves, and gradual removal of the bell-shaped body 46, which enables the item of footwear to be picked up and taken away to the station 10'.

From the foregoing description, it is evident how, as compared to the known modalities of production, the fact of providing a layer of solid gluing material spread uniformly over the entire surface of the sole, with a pre-set thickness and only within the perimetral edge of the sole itself enables, in the first place, footwear to be obtained presenting a high and constant degree of quality and finish and hence a high aesthetic level . The exact dosage of the gluing material inhibits, in fact, any onset of undesirable dripping and eliminates the need for any operation of preparation of the parts to be joined together, such as carding, and spreading glue both on the upper and on the sole, and of final cleaning, which, in addition to being costly and relatively complex operations, are notoriously particularly pollutant.

In addition to this, the plant 1 described enables a uniform and stable connection of the sole to be obtained irrespective of the geometrical conditions or the conditions of memory of the sole or of the upper, in so far as melting of the gluing material in conditions of pressure favours the diffusion of the liquefied gluing material between the sole and the upper and filling of all the gaps pr/esent between the sole and the upper, whilst maintenance of the conditions of forcing until complete resolidification of the gluing material determines a high stability of join and shape.

The fact of using cushion bodies to force the upper and the sole against one another makes it possible to exert not only an energetic forcing action but also a uniform forcing over the entire item of footwear. Unlike the known solutions, in fact, the inflatable cushions 37 free the upper 4 and the corresponding supporting member 33 from any external rigid constraints. Said uniformity of forcing enables a reduction, once again with respect to the known solutions, of the amount of the forcing action and hence of the stresses transferred to the upper, which, consequently, must no longer be oversized with evident reduction in costs and use of materials. The absence of rigid constraints between the members for supporting the uppers and the outside world in conditions of pressing then enables preservation of the supporting members themselves in so far as onset of concentrated stresses in the area of interface between the pin and the supporting member is prevented, said stresses being responsible for failure due to fatigue of the supporting member itself even after a relatively small number of uses . From the foregoing description it is moreover evident how the modes of construction described enable definitive elimination of the use of gluing materials of the solvent type, which, as is well known, emit considerable amounts of unpleasant fumes, and the toxic residue of which frequently comes into contact with the user's foot notwithstanding the operations of final cleaning envisaged. In other words, elimination of solvent gluing materials improves the working conditions of operators responsible for the production of footwear and the environmental conditions in general, as well as the healthiness of the item of footwear.

According to a different embodiment (not illustrated) , each of the cushions 50 housed in the bell-shaped bodies 46 comprises a seat for at least partial housing and positioning of the sole 3 and a plurality of holes which can be connected to a vacuum source for withholding the sole 3 so that it engages the aforesaid seat, thus providing an automatic positioning of the sole 3 on the corresponding upper 4 without any need to envisage the station 8.

From the foregoing description it is evident that modifications and variations can be made to the method and plant 1 described without thereby departing from the sphere of protection defined by the annexed claims.

In particular, the mode and/or the conveyors for displacement the uppers and the soles could be different, as likewise the inflatable-cushion bodies could be different in number and as regards shape. In the case of soles with a heel, it is possible to envisage shells for protection of the heel and of the cushion bodies themselves. Finally, the cushions 37 could not uncouple the supporting members 33 from the completely respective pins 32 but only slide them off in such a way that the pins 32 engage the corresponding blind hole with radial play. Finally, it is evident that the sources of heat 52 set in each of the inflatable cushion bodies 50 may be replaced by a single common source of heat set in the intermediate area of pressing 9 and associated to the bell-shaped body 46, which is located in the area 9 and in which the gluing material must be heated.

Claims

C L A I M S

1. A method for connecting a sole element to an upper of an item of footwear; the method comprising the steps of setting a gluing material between the sole element and the upper, coupling the sole element and said upper to one another, and exerting an action of pressing of the sole element and of the upper against one another; said method being characterized in that the interposition of the gluing material comprises the steps of laying at least one layer of substantially solid gluing material only on one between said sole element and said upper, and in that said action of pressing is carried out using first and second opposed inflatable cushion means .

2. The method according to Claim 1, characterized in that said layer of gluing material is laid only on top of said sole element .

3. The method according to Claim 1 or Claim 2, characterized in that laying of said gluing material is carried out so as to provide a continuous layer of uniform thickness.

4. The method according to Claim 3, characterized in that laying of said gluing material is carried out by laying an extensive uniform layer of gluing material on a supporting surface, superimposing on said extensive layer the sole element in such a way that at least the surface of the sole element is set in contact with the gluing material, forcing the sole element against said supporting surface, and detaching at least the sole element and the corresponding underlying portion of gluing material from said supporting surface.

5. The method according to Claim 4, characterized in that laying of said gluing material, superposition of said sole element, forcing of the sole element against said supporting surface, and detachment of the sole element and of the corresponding underlying portion of gluing material from the supporting surface are performed during displacement of said supporting surface in a direction of feed.

6. The method according to any one of the preceding claims, characterized in that it comprises a step of partial connection of said sole element to said upper.

7. The method according to Claim 6, characterized in that said step of connection is performed by providing between the sole element and the upper one or more point-like joins via said gluing material .

8. The method according to any one of the preceding claims, characterized in that it comprises a step of heating said gluing material after coupling the sole element and the upper to one another.

9. The method according to Claim 8, characterized in that said heating is performed in a condition of substantial maximum pressing of said sole element against said upper.

10. The method according to any one of the preceding claims, characterized in that it comprises a step of humidification of said gluing material .

11. The method according to Claim 10, characterized in that said step of humidification of said gluing material is performed during a step of heating of said gluing material.

12. The method according to any one of Claims 8 to 11, characterized in that heating of said ■ gluing material is performed using a source of heat set inside said cushion means .

13. The method according to Claim 10, characterized in that humidification Of said gluing material is performed by varying the humidity of at least one between said sole element and said upper.

14. The method according to any one of the preceding claims, characterized in that said action of pressing is performed using a forming body set inside the upper and supporting the forming body, the upper, and said sole element only via said inflatable cushion means.

15. The method according to Claim 14, characterized in that said action of pressing is performed by inflating said inflatable cushion means so as to free at least partially said forming support from an initial coupling of the forming support to a fixed attachment body.

16. A plant for connecting a sole element to an upper of an item of footwear; the plant comprising supply means for setting a gluing material between the sole element and the upper, and forcing means for exerting an action of pressing of the sole element and of the upper against one another,- said plant being characterized in that said supply means comprise forming means for forming at least one layer of substantially solid gluing material only on one between said sole element and said upper, and in that said pressure means comprise first and second opposed inflatable cushion means.

17. The plant according to Claim 16, characterized in that said forming means comprise dispenser means and transfer means for providing a continuous layer of uniform thickness only on said sole element.

18. The plant according to Claim 17, characterized in that said dispenser means dispense a thermohygroreactive material.

19. The plant according to Claim 17 or Claim 18, characterized in that said transfer means comprise a supporting surface carrying an extensive layer of gluing material formed by said dispenser means, means for forcing the sole element against said supporting surface, and separator means for detaching the sole element and the corresponding underlying portion of gluing material from the supporting surface.

20. The plant according to Claim 19, characterized in that said^J pressure means comprise at least one forcing roller set facing said supporting surface and at a distance from the supporting surface approximating by defect the sum of the thicknesses of said sole element and of the layer of gluing material .

21. The plant according to Claim 20, characterized in that said supporting surface is mobile in a direction of feed.

22. The plant according to any one of Claims 16 to 21, characterized in that it comprises heating means for heating said gluing material set inside said inflatable cushion means .

23. The plant according to Claim 22, characterized in that said heating means comprise microwave means.

^■24. The plant according to any one of Claims 16 to 23, characterized in that it comprises spraying means for spraying a jet of moistening fluid towards at least one between said sole element and said upper.

25. The plant according to any one of Claims 16 to 24, characterized in that it comprises: a supporting member and, for each said upper, a respective forming body set inside the upper; coupling means, which can be released under the thrust of said inflatable cushion means, being provided for constraining said forming body to said supporting -member when said inflatable cushion means are set in a deflated resting condition and for uncoupling the forming body from the supporting member when said inflatable cushion means are set in an inflated pressing condition.

26. The plant according to any one of Claims 16 to 25, characterized in that it comprises first and second endless- belt conveyor means; said first endless-belt conveyor means supporting a plurality of first inflatable cushions and said second endless-belt conveyor means supporting a plurality of second inflatable cushions, each designed to co-operate with a respective first inflatable cushion body to define a variable- volume seat for housing a respective said upper and a respective said sole element.