MX2007004059A - Mould for manufacturing shoes with encapsulated insole. - Google Patents

Abstract

Described is a mould for manufacturing shoes with encapsulated insole, the mould has a last that includes a sole. Two cooperating halves are closed over the last so as to form the shoe upper. A mould sole is coupled inside the cooperating halves so as to form the outsole. Within the mould, a first injection port crosses the insole through at least an aperture included therein, said first injection port supporting the insole in such a position that the same is separated from the sole and the mould sole, thus discharging a thermoplastic material over the insole. A second injection port is useful for discharging the thermoplastic material under the insole. Both the first and the second injection port simultaneously discharge the thermoplastic material causing the insole to be enclosed by the thermoplastic material so that the outsole is encapsulated. A third injection port is useful for flowing the thermoplastic material so as to form the shoe upper.

Description

"MOLD TO MANUFACTURE A FOOTWEAR WITH ENCAPSULATED TEMPLATE FIELD OF THE INVENTION The present invention is related to the techniques used in the design and manufacture of footwear and more particularly, is related to a mold for manufacturing a footwear with a template encapsulated in the sole of the same.

BACKGROUND OF THE INVENTION The use of footwear by humans goes back to the rudimentary use of materials obtained from nature such as woven vegetable fibers and, subsequently, the use of animal hide. At present, there are activities that, due to their nature, require the use of footwear with special characteristics of impermeability, durability and without losing sight of comfort for the feet. Of these activities, those in which it is in contact with wet, greasy, moldy surfaces, contaminated with corrosive or toxic substances or simply at a temperature different from that found in the human body, have required adequate protection for the feet of the individual. These activities have also made it necessary to use anti-skid soles, especially in commercial or industrial areas whose surfaces are slippery, or they are on higher platforms or in areas of difficult access, where there is a risk that a person falls from a height considerable risk of accidental contact with operating machinery, receiving electric shocks or suffering burns. With particular reference to temperature changes, the use of hot water is common for the cleaning of productive areas, which are subsequently rinsed with cold water, so that workers are exposed to sudden changes in surface temperature, making that the use of special footwear is mandatory for the worker's own safety. In all these places of industrial activities, it is customary to use waterproof footwear, which is electrically and thermally insulating, with mechanical resistance and anti-slip sole, which is why day by day it is about improving the characteristics of work footwear. In this sense, one of the most used options to achieve thermal insulation and provide comfort to the foot, is to use a template within the shoe itself, but this solution has the disadvantage that the template has to be replaced by a new one when it wears out, In addition, if the template is made of cardboard or foamed rubber, it can contract inside the shoe, making it uncomfortable, and this type of insoles keeps moisture. On the other hand, if the work footwear seeks protection against sharp materials and rough surfaces, usually hardens the material of which the sole is made, which causes it to lose flexibility and traction becoming slippery. Another option for protection is to thicken the sole of the footwear, which implies a greater weight and the use of a greater amount of material, so that the cost increases and the footwear becomes uncomfortable. Within the prior art, there are some types of footwear that incorporate elements of protection such as the case of the Mexican patent application No. 9701688, where through a process it is achieved that the template is integrated into the sole and this in turn joins with cutting, using a special direct injection mold. The mold used consists of two lids, of which the lower one houses the cut of the footwear and the insole, while the upper one has two cavities corresponding to the sole to be injected. It is important to note that in the shoes obtained by this method, the template is not isolated from the foot.

Similarly, British Patent No. 1, 436,501 can be cited, which describes a footwear that incorporates a protective insole on the sole and a cap at the tip, which are incorporated within the walls of the footwear. In a particular way, the material used for the manufacture of these boots is a foamable plastic material, such as polyurethane. That is to say, the plastic of this shoe is introduced into a mold and then left to foam. Furthermore, for the purpose of holding the cap and the template in the mold, spacer elements are used, however, any expert in the art will anticipate that said spacers will inevitably leave spaces within the product once the polyurethane has expanded, which reduces the comfort and protection of the jig or cap, that is, they can move from their place. In the Mexican patent application No. PA / A / 2006/003957, from the same inventor as that of the present invention, there is described an injected shoe that has a template encapsulated between the cut and the sole of the shoe and that is hidden from the shoe. view of a user. The footwear also incorporates an inner lining that makes it easy to put on and take off the footwear, which is made with two thermoplastic materials or injection colors, ie a material for the cut and another for the sole, needing a mold that has two elements of sole , one that closes the mold when the cutting material is injected and the other closes the mold when the material is injected to form the sole. The process for manufacturing this shoe has two stages of injection, one to inject and form the cut and the other stage to inject the material of the sole, with these stages is achieved encapsulate the template properly between two thermoplastic materials with different characteristics, ie one more flexible than the other. As seen from the above, in the prior art the shoes with encapsulated insole can be manufactured with two injection colors or with only one, in particular the latter case presents an important challenge since the mold must allow placing the template in a place so that it does not move when the thermoplastic material flows, since it has been observed that precisely the injection material causes the template to move, which causes that the template is not properly encapsulated once the thermoplastic material solidifies , for example, sometimes the template protrudes from below and from the sides of the sole of the footwear or protrudes from the internal part of the footwear. There is a main reason why today it is required to continue manufacturing footwear with encapsulated templates with a single color of injection, this reason is related to the fact that footwear is cheaper and its process faster to perform. Although prior art contemplates the production of a shoe by thermoplastic materials that are injected into a mold, the level of perfection has not been optimal to ensure that the template is encapsulated within the sole in a practical and efficient manner with The purpose of providing protection to the foot so that the irregularities of the floor do not feel because of the thinness or softness of the material with which the footwear is made and the thermal changes in the floor are not felt by temperature transmission. In more precise words, the problem lies in making the template not move at the time of injecting the thermoplastic material into the footwear manufacturing mold.

BRIEF DESCRIPTION OF THE INVENTION In order to solve the problems of the prior art molds for manufacturing shoes with encapsulated insoles made with a single thermoplastic injection material, a mold has been designed where the template is in a position such that it allows the material injection thermoplastic flow properly above and below the template, making it is properly encapsulated in the sole. More particularly, the mold of the present invention comprises a last with the form corresponding to the internal part of the footwear, the last has a last plant, that is, a portion that serves to shape the sole of the foot inside the footwear; also each time a shoe is manufactured, the last is covered with a lining, which is preferably a textile mesh. In the mold there are two cooperating halves that close on the sides of the last in such a way that they are separated from it to form the cut of the footwear. Additionally, an important element of the mold is a mold sole that engages within the cooperating halves and faces the mold plant to close the mold. Precisely, the mold sole forms the sole of the footwear. An important element of the mold of the present invention is a first port or injection point located in the mold sole and passing through the template through at least one opening included in the template, the first injection port supports the template in such a position that it is separated both from the last plant and from the mold sole, the first injection port discharges the thermoplastic material on the template. The mold additionally comprises a second injection port located in the mold sole and discharging the thermoplastic material below the template, the first and second injection ports work simultaneously, ie, discharge the thermoplastic material above and below the template at the same time, which causes the template to be surrounded by the thermoplastic material without the template touching the last plan and the mold sole. To form the shoe cut, the mold comprises a third port or injection point located in one of the cooperating halves of the mold, this third injection port flows the thermoplastic material to form the shoe cut. Once the thermoplastic material solidifies, the lining covering the last is adhered to the inner part of the shoe cut. While the template is immersed within the injection thermoplastic material by the simultaneous discharge of the thermoplastic material above and below the template, in optional embodiments of the mold of the present invention, the mold additionally comprises means for separating the template from the mold. surface of the last plant and / or the mold sole. In case there is an upward or downward displacement of the template at the time of injection, the separation means will prevent the template from touching the mold sole or the last plant. The separation means are provided either: i) on at least one of the faces of the template; and / or ii) on the surface of the last plant; and / or iii) on the surface of the mold sole. The separation means are selected from the group comprising protuberances, ridges, bolts and posts having a height of about 2 mm to about 6 mm; cylindrical poles are preferably used.

BRIEF DESCRIPTION OF THE FIGURES The novel aspects that are considered characteristic of the present invention, will be established with particularity in the appended claims. However, the invention itself, both for its structural organization and its form of use, together with other objects and advantages thereof, will be better understood in the following detailed description of cin preferred embodiments of the present invention., when read in conjunction with the accompanying drawings, in which: Figure 1 is a side perspective view of a first encapsulated footwear obtained by the mold of the present invention, wherein the first footwear has the shape of one boot. Figure 2 is a side perspective view of a second encapsulated footwear obtained by the mold of the present invention, where the second footwear has the shape of a moccasin.

Figure 3 is a partial and enlarged view of a cross-sectional cut taken along the line AA 'in the shoe shown in Figure 1. Figure 4 is a side perspective view of a mold for producing footwear with encapsulated template, the mold being constructed in accordance with a first preferred embodiment of the present invention. Figure 5 is a front perspective view of the mold of Figure 4 where the mold sole has been removed for clarity purposes. Figure 6 is a sectional view in longitudinal section of a portion of the mold of Figure 4 when it is closed and ready to inject the thermoplastic material. Figure 7 is a top plan view of the template that is encapsulated in the mold of the present invention. Figure 8 is a bottom plan view of the jig of Figure 7. Figure 9 is an enlarged view in the area of the mold floor of a mold constructed in accordance with a second preferred embodiment of the present invention. Figure 10 is a side and top perspective view of a template used in an alternative embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION In order to explain the type of footwear that it is desired to produce by means of the mold of the present invention, reference is made to Figures 1 and 2 of the attached drawings, in Figure 1 a first footwear 10 is shown. with the shape of a boot, while in Figure 2 a second shoe with the reference 1 1 is shown which has the shape of a moccasin. In both shoes 10 and 11 a sole 12 can be distinguished; and a cut 13 which is the part of the footwear that joins the sole and which covers the upper portion of the foot. In particular, the first shoe 10 has a platform 14 with a flat horizontal surface in the heel area, the platform 14 protrudes from the cut 13 and serves so that a user can rest the opposite foot on said platform 14 and help remove the Footwear The first and second shoes 10 and 11 have common characteristics that are obtained by the mold of the present invention, in particular both shoes are manufactured with a single thermoplastic injection material to form both their sole 12 and its cut 13 and have a sole encapsulated in the sole 12, in other words, both shoes have similar characteristics because the template is encapsulated by a mold specially designed for that purpose and where the structural relationship between its elements is preserved regardless of the final shape of the footwear produced. In connection with the above, reference is now made to Figure 3, which shows a cross section taken along the line AA 'in the first shoe 10, this figure is extremely useful in order to appreciate the template 15, which is it is encapsulated in the sole 12, that is, it is hidden and surrounded by the thermoplastic material with which the sole 12 is made, but it provides protection to the user's foot. The template 15 is intended to provide protection to the foot so that irregularities of the floor and thermal changes are not felt, the insole 15 lies below the surface of the sole of foot 18 within the footwear. In this same Figure 3, a liner 19 can be seen which preferably is a textile mesh or a fabric that is adhered to the internal part of the cut 13. The lining 19 has two main functions, one is to easily demold the footwear once is produced, and the second function is to facilitate the introduction and removal of footwear from the foot of the user, since the foot can easily slip through the lining 19 inside the footwear. Once the footwear to be produced has been described, the mold by means of which it is obtained is described below, for which reference is made to Figures 4 and 5 which show a mold 21 constructed in accordance with a first embodiment of the invention. present invention and which serves to obtain in particular a footwear in the form of boot as illustrated in Figure 1. The mold 21 for manufacturing a footwear with encapsulated insole has a form 30 with the shape of the inner part of the footwear that is you want to produce, the last 30 has a floor of the last 31 that shapes the surface for the sole of the foot inside the footwear produced, the last 30 occupies a central position and is arranged horizontally in the mold 21 this means that the plant of last 31 is facing the face of an operator so that he can unmold footwear. The mold 21 also has two cooperating halves 40 and 41, a lower one which is the one with the numerical reference 40 and an upper one that is identified with the reference 41, the cooperating halves close on the sides of the last 30 and are separated from each other. the same, leaving a hole that is filled by the thermoplastic material in order to form the shoe cut. The cooperating halves 40 and 41 of the mold 21 include male-female terminals 44 to ensure a hermetic seal of both in the mold 21. Since in the mold 21, a boot-shaped shoe such as that illustrated in FIG. Figure 1, the cooperating halves 40 and 41 have a rear cavity 43 (see Figure 5) to form the platform 14 on the back of the shoe as identified in Figure 1. Returning to Figures 4 and 5, another important part of the mold 21, is a mold sole 50 (Figure 4), the mold sole 50 engages within the cooperating halves 40 and 41 and facing the last 31 floor at the time of closing the mold 21. The sole of mold 50 provides a hermetic seal on the mold 21. The arrows of movement 17 illustrate the manner in which the cooperating halves 40 and 41 and the mold sole 50 close on the last 30 so as to be able to inject the thermoplastic material. In order to properly encase the template 15, it must be separated from the last plant 31 and from the mold sole 50, for this the mold 21 comprises a first injection port or point 57 located on the sole of mold 50 and passing through the template 15 through an opening 16 included therein; the first injection port 57 causes the template to be separated both from the surface of the last plant 31 and from the surface of the mold sole 50, i.e. it supports it. The first injection port 57 discharges the thermoplastic material onto the template 15. In a preferred embodiment of the present invention, the first injection port 57 is a discharge valve or a nozzle. Likewise, the opening 16 of the template has a shape such that it prevents the template 15 from rotating pivotally on the first injection port 57. Even in one embodiment the opening 16 and the first injection port have the same The cross-sectional shape, for example, may have an oval, elliptical or polygon shape, preferably has a square, rhomboidal or rectangular shape, which makes it impossible for the template to rotate on the first injection port in the manner indicated. The circular shapes would not be recommendable since it would be possible to rotate the template on the first injection port, causing at the end of the injection that the template be visible on the sides of the sole of the footwear produced. Also, the mold 21 includes a second port or injection point which in the embodiment described is composed of a plurality of injection holes 55 provided in the mold sole 50 and which make the thermoplastic material flow flush with the surface of the mold. the mold sole and below the template 15. The first injection port 57 and the injection orifices 55 that make up the second injection port work simultaneously, that is, they discharge the thermoplastic material above and below the template 15 at the same time, which causes the template to be surrounded within the thermoplastic material and prevent the template from touching the surface of the last plant 31 or the surface of the mold sole 50. In the embodiment described, the Injection ports 55 surround the first injection port 57 in the mold weld 50.

Similarly, the mold 21 has a third injection port or point 42 (see Figure 5) located in the upper cooperating half 41. Through this third injection port 42 the thermoplastic material is flowed to form the shoe cut . The thermoplastic material for cutting is preferably injected into the mold 21 in a location corresponding to the upper edge of the cut of the footwear already manufactured, from said second injection port 42, the thermoplastic material flows between the space between the last 30 and the cooperating halves 40 and 41 to form the shoe cut and join with the thermoplastic material of the sole. Now, reference is made to Figure 6 in order to more concretely describe how the first injection port 57 and the injection orifices 55 work together so that the template 15 is properly immersed in the shoe sole without protrude from the sole by nowhere. Figure 6 shows a view in longitudinal section of a portion of the mold 21 when it is closed, this view of Figure 6 corresponds to the contact surface of the upper half on the lower half 40 and in it the male end 44 is observed and the liner 19 covering the last 30, this liner 9 is adhered to the footwear once the thermoplastic material solidifies. As seen in Figure 6, the first injection port 57 passes the template 15 through the opening 16, and at the same time the first injection port supports the template to separate it both from the last plant 31 and from the The surface of the mold sole 50, that is to say the template 15, stops both elements 31 and 50 without touching them so that the thermoplastic material can flow freely. Preferably, the opening 16 and the first injection port 57 have the same rectangular shape in cross section so that the template 15 does not rotate on the first injection port 57. When the mold 21 is closed, the first injection port 57 discharges the thermoplastic material without any kind of impediment between the template 15 and the last plant 31. In turn, the plurality of injection orifices 55 inject the thermoplastic material between the surface of the mold sole 50 and below the template 15 When performing this injection simultaneously, what happens is that the thermoplastic material that is discharged above the template 15 pushes it down, while the injection material that is discharged below template 15 pushes it up , in this way the thrust forces generated by the injection material on and below the template 15 tend to be nullified, consequently the plant illa 15 does not move from its place so that it is properly encapsulated in the sole of the sole once the injection material solidifies. The first injection port 57 is removed and leaves only an almost imperceptible mark on the sole of the finished footwear. In Figures 7 and 8 the template 15 used in the described modality is shown, in both figures the opening 16 that is pierced by the first injection port is observed. In the present invention, the jig 15 is made with a material selected from the group comprising: metal, plastic, flexible polymers, cardboard, paper fiber and combinations thereof. Likewise, the template 15 does not necessarily have to be complete since a portion of it can be occupied, for example, the front portion thereof can be used, that is, a template covering the metatarsal area of the foot (ball of the foot). foot) without having to extend towards the heel area of the foot since this portion will be protected by the heel of the footwear produced. The first injection port 57 preferably traverses the template 15 at its front portion. As mentioned, the opening 16 can have different sizes and shapes, in addition, the mold can include more injection points through the template; consequently, more injection points would be needed to discharge the material above the template 15. In addition, the template 15 may include a plurality of perforations that pierce the template 15 from one side to the other to allow the passage of the thermoplastic material from the face bottom of the template towards the top face or vice versa, further improving the encapsulation of the template 15.

Now, reference is made to Figure 9 in order to describe a second preferred embodiment of the present invention, in this embodiment the same numerical references are retained as those used in Figures 4, 5 and 6 for the common and identical elements, with except that the mold of this second embodiment is now identified with the reference 22 and is characterized mainly by the fact that it comprises separation means 32 which, in the case of an upward or downward displacement of the template, allow the stencil 15 does not touch the last floor surface 31 or the sole sole surface 50. As seen, these separation means 32 are distribuin the second embodiment on the last floor surface 31 and on the floor surface. the mold sole 50, although it is also possible to incorporate them only in one of these surfaces. In Figure 9 the first injection port 57 is seen passing through the template 15 through the opening 16 and the injection orifices 55 whose action has already been described previously. The cooperating halves 40 and 41 closing on the last 30 are also observed. Finally, in Figure 10, a template 15 is shown which is used in alternative embodiments of the present invention, more particularly, the template 15 has on its upper face and on its lower face the first separation means 32 which can also be locaonly on one of its faces. Likewise, the opening 16 is observed to be passed through the first injection port. These posts prevent the template from reaching the mold floor or the mold sole if the forces of the injection material above and below the template fail to balance. The separation means 32 are made of the same material as the template 15 is made. In summary, the first separation means 32 can be locai) on at least one of the faces of the template; and / or ii) on the surface of the last plant and / or iii) on the surface of the mold sole. In the illustraembodiments, the separation means are selecfrom the group comprising protuberances, ridges, bolts and posts having a height of about 2 mm to about 6 mm. Preferably, the separation means 32 are specifically cylindrically shaped posts uniformly distribuon both faces of the template 15. In a specific embodiment, the posts that are on the periphery of the surface of the last floor 31, of the sole of mold or in the template have a higher height than the remaining posts. Also, when the separation means 32 are included in the mold sole or the sole floor, the template 15 may include perforations that are pierced by some of the posts so that the template does not move at the time of injection of the material. thermoplastic In a further embodiment, the elements of the mold are repeain a mirror relationship in order to manufacture at the same time the right copy and the left copy corresponding to a pair of shoes. The thermoplastic material for making the shoe to an injection color is a thermoplastic material selecfrom the group comprising PVC, synthetic rubber, thermoplastic rubbers (TPR) and combinations thereof. The mold of the present invention has important advantages over previous techniques for encapsulating a template in those shoes that are obtained by injection. Particularly, the mold incorporates a first injection port that crosses the template to separate it from the mold floor and the mold sole, the first injection port supports the template which can not pivot on the first port of the mold. injection every time it would be visible in the sole of the footwear. Furthermore, for better operation of the invention it is possible to incorporate separation means as explained. Even though in the above description preferred embodiments of the present invention have been shown and described, it should be emphasized that numerous modifications are possible thereto, without departing from the true scope of the invention.

As for example, the modifications may be the selection of footwear manufacturing materials or the shaping of the separation means used in the mold, therefore, the present invention should not be restricted except by what is required by the prior art. and by the appended claims.

Claims (11)

1. NOVELTY OF THE INVENTION CLAIMS 1. A mold for manufacturing a footwear with encapsulated insole, characterized in that it comprises: a) a last with the form corresponding to the internal part of the footwear, the last having a last plant; b) a lining that covers the last; c) two cooperating halves that close on the sides of the last in such a way that they are separated from it to form the cut of the footwear; d) a mold sole that engages within the cooperating halves and facing the to the last plant; the sole of the mold forming the sole of the footwear; e) a first injection port located in the mold sole and traversing the template through at least one opening included in the template, the first injection port holding the template in a position such that it is separated from both the mold plant and the mold sole, the first injection port discharges the thermoplastic material on the template; f) a second injection port located in the mold sole and discharging the thermoplastic material below the template, the first and second injection ports discharging the thermoplastic material at the same time, which causes the template to be surrounded by the thermoplastic material without the template touching the last plant and the mold sole; and, g) a third injection port located in one of the co-operating halves of the mold and flowing the thermoplastic material to form the shoe cut; wherein the lining is adhered to the inner part of the shoe cut once the thermoplastic material solidifies.
2. 2. - A mold for manufacturing a shoe with encapsulated insole, according to claim 1, further characterized in that the first injection port is a discharge valve.
3. 3. - A mold to manufacture a footwear with encapsulated insole, according to claim 1, further characterized in that the opening of the template has a shape such that prevents the template from rotating on the first injection port as a pivot.
4. 4. A mold for manufacturing a shoe with encapsulated insole, according to claim 3, further characterized in that the first injection port and the opening of the template have the same shape in cross section.
5. 5. A mold for manufacturing a shoe with encapsulated insole, according to claim 4, further characterized in that the opening and the first injection port have an oval, elliptical or polygonal shape.
6. 6. - A mold for manufacturing a footwear with encapsulated insole, according to claim 5, further characterized in that the opening and the first injection port have a square, rhomboidal or rectangular shape.
7. 7. - A mold to manufacture an encapsulated footwear footwear, in accordance with claim 1, further characterized in that the insole includes a plurality of perforations that transfer from one side to another the template to allow the passage of the thermoplastic material from the upper side to the bottom face of the template or vice versa.
8. 8. A mold for manufacturing a footwear with encapsulated insole, according to claim 1, further characterized in that the mold additionally comprises means for separating the template from the surface of the last plant and / or from the mold sole in case that there is an upward or downward displacement of the template at the time of injection, wherein the separation means are provided either: i) on at least one of the faces of the template; and / or ii) on the surface of the last plant; and / or iii) on the surface of the mold sole.
9. 9. A mold for manufacturing a shoe with encapsulated insole, according to claim 8, further characterized in that the separation means are selected from the group consisting of protrusions, poles, posts and bolts.
10. 10. A mold for manufacturing a shoe with encapsulated insole, according to claim 9, further characterized in that said protuberances, posts, shoulders and bolts have a height of 2 mm to 6 mm.
11. 11. A mold for manufacturing a shoe with encapsulated insole, according to claim 8, further characterized in that said first separation means are poles provided on at least one of the faces of the template. 12-. A mold for manufacturing a footwear with encapsulated insole, according to claim 1, further characterized in that said second injection port is integrated by a plurality of injection orifices that discharge the thermoplastic material flush with the surface of the mold sole and below the template. 13. A mold for manufacturing a shoe with encapsulated insole, according to claim 12, further characterized in that the injection holes surround the first injection port in the mold sole. 14. A mold for manufacturing a shoe with encapsulated insole, according to claim 1, further characterized in that the lining is a textile mesh. 15. A mold for manufacturing an encapsulated footwear shoe, according to claim 1, further characterized in that a boot or a moccasin is produced in the mold. 16. A mold for manufacturing a footwear with encapsulated insole, according to claim 15, further characterized in that the footwear is a boot and wherein the cooperating halves of the mold have a cavity that forms in the cut a platform external to the footwear by above the heel, the platform serving to remove the footwear by supporting the opposite foot on said platform. 17. - A mold for manufacturing a footwear with encapsulated insole, according to claim 1, further characterized in that the injection thermoplastic material is selected from the group comprising PVC, synthetic rubber and thermoplastic rubber. 18. - A mold for manufacturing a shoe with encapsulated insole, according to claim 1, further characterized in that the last has a horizontal arrangement in the mold such that the last plant faces the operator. 19. A mold for manufacturing a footwear with encapsulated insole, according to claim 1, further characterized in that the insole is manufactured with a material selected from the group comprising metal, plastic, flexible polymers, cardboard, paper fiber and combinations of the same.