ITPD20080308A1 - SHAPE FOR MOLDS OF FOOTWEAR OR FOOTWEAR PARTS - Google Patents

Description

TITLE

SHAPE FOR FOOTWEAR MOLDS OR FOOTWEAR PARTS

DESCRIPTION

The present patent relates to equipment for molding plastic materials and in particular it concerns a new last for shoe molds or shoe parts.

Apparatus for molding footwear or parts of footwear in plastic material are known consisting of a plurality of molds mounted on a carousel frame which positions each mold, in succession, at the various processing stations.

Each mold is generally made up of two half-molds, on which the negative shape of the object to be made is hollowed out, and by an element capable of being interposed between the two half-molds, inside said hollowed shape, having the shape positively of the object to be made and commonly called form.

Forms made of plastic are known.

Such plastic forms have various drawbacks. First of all, they are deformable and in particular, subjected to frequent use and high temperatures, they slowly reduce in size and deform progressively, giving rise to manufacturing defects of the finished object, such as burrs and unwanted deformations.

In addition, the plastic form, after prolonged use, can undergo breakage. In fact, a plastic form can be used for a relatively limited number of times; for example, for an hourly production of 100 shoes, it must be replaced on average every three months, causing production interruptions and leading to unavoidable material and labor costs.

Forms made of metal and solid are also known. These solid metal forms are substantially non-deformable and have a longer service life than plastic forms, as they are more resistant to wear and high temperatures, but they involve other drawbacks.

Said monolithic metal forms are full and therefore have a greater weight than the plastic forms, thus making it impossible to move them in automatic, so-called robotic, equipment of the type commonly used in molding.

Furthermore, it is not possible to use larger robotic equipment, which cannot be conveniently handled in limited spaces and volumes as occurs in molding operations.

Furthermore, as described above, the forms of the known type are made in a rigid piece and therefore the operations of inserting and removing the form from the two half-molds is difficult and can only be done after the complete opening of the half-molds.

In order to obviate all the aforesaid drawbacks, a new type of last for shoe molds or parts of footwear in plastic materials has been studied and realized, made of metal and in particular of aluminum or its alloys and where said lasts are internally hollow.

The main aim of the present invention is to simplify the procedures for handling the last by mechanical manipulators and robots, reducing the weight of the last, which is in fact hollow.

Another purpose of the present invention is to have a longer life, being made of metal material and in particular of aluminum or its alloys, that is, of material with greater resistance to wear and less deformable than the currently used plastic materials.

Another purpose of the present invention is to accelerate and simplify the operations of inserting and removing the form from inside the mold, formed for example by two or more half-molds; the new shape, according to one of its possible embodiments, in fact includes detachable and / or movable parts with respect to each other.

These and other direct and complementary purposes are achieved by the new shape for molds of footwear or parts of footwear in plastic materials, made of metal and in particular of aluminum or its alloys, comprising at least two hollow parts which can be coupled exactly to each other. making a hollow shape in an externally complete piece.

The new shape includes, in its main parts, at least two complementary parts or semi-shapes, each of which is substantially one half of the shape, cut in width according to a median plane, i.e. a plane passing through the main longitudinal axis of the shape, joining basically the heel area with the toe area.

The two half forms are made of metal, in particular preferably of aluminum or its alloys, and have a concave or hollow shape, so that, with their exact coupling, an externally complete and internally hollow shape is created.

Said half-forms can be coupled, in a stable or removable way, for example by welding or by using bolts or other fastening means.

The shape, obtained by coupling the two half shapes, is therefore an internally hollow metal piece. The new shape has greater resistance to wear and stresses during processing than plastic materials and is less deformable.

The new shape therefore has a longer life and needs to be replaced less frequently than the plastic shapes.

The new shape is also light, being internally hollow, and therefore does not have the drawbacks typical of non-hollow metal shapes.

According to a possible solution, each half form in turn comprises at least two sections which can be coupled together to form the half form, and where each section of the first half form can also be coupled to the corresponding section of the second half form.

These sections of each half-shape, each coupled to the corresponding section of the complementary half-shape, are detachable and / or inclinable with respect to each other.

In particular, each half-shape is expected to comprise a first anterior section, which substantially affects the front part of the half-shape itself, i.e. the part of the tip, the back and a portion of the sole, and a second section, which substantially affects the rear part. of the seed form, that is the part of the heel and the remaining portion of the plant.

The shape, obtained by coupling the corresponding front and rear sections of each half-shape, is therefore composed of a rear part, formed by the two coupled rear sections, and of a front part, formed by the two coupled front sections and where said front and said rear part are inclinable with respect to each other in such a way as to simulate the natural movement of a foot, where the tip of the foot and the front part of the sole bend with respect to the heel and the rear part of the sole.

This relative movement of the sections that make up each half mold allows to reduce the overall longitudinal dimensions of the mold itself, which can be more easily inserted or removed from the mold formed by the two half molds.

The characteristics of the new shape will be better clarified by the following description with reference to the drawing tables, attached by way of non-limiting example.

Figure 1 shows in side view the two complementary half-shapes (Sa, Sb) forming the shape (S) schematically represented in three-dimensional view in Figure 1a.

In figure 2 the two complementary half shapes (Sa, Sb) forming the shape (S) are in side view, each half shape (Sa, Sb) being in turn formed by the coupling of two sections (Sa1, Sa2), ( Sb1, Sb2), respectively an anterior section (Sa1, Sb1) and a posterior section (Sa2, Sb2). The shape (S) obtained is schematically represented in three-dimensional view in Figure 2a.

Figures 3a and 3b schematically show the reciprocal movement between the anterior section (Sb1) and the rear section (Sb2).

According to the embodiment shown in figures 1 and 1a, the new last (S) for molds of footwear or parts of footwear in plastic materials, made of metal and in particular of aluminum or its alloys, comprises two complementary parts or semi-forms (Sa , Sb) which can be coupled, each of which is substantially one half of the shape (S), cut in width according to a median plane (X) substantially joining the rear region of the heel (T) with the anterior region (P) of the toe.

The two half forms (Sa, Sb) have a hollow or concave shape, so that their coupling creates a complete and internally hollow shape (S), represented in figure 1a.

Said two half-shapes (Sa, Sb) are coupled together by joining their respective perimeter edges. On all or part of the perimeter edge of one of the two semi-forms (Sa, Sb) there are seats (S21, S22) and / or reliefs (S31, S32) suitable for insertion into reliefs (S31, S32) or seats (S21, S22) present on the edge of the complementary half form (Sb, Sa), so as to make the shape (S) obtained by coupling the two half forms (Sa, Sb) well closed.

Said half-shapes (Sa, Sb) are connected to each other in a removable or non-removable way by welding or fastening means such as bolts or other. In particular, it can be envisaged that said semi-shapes (Sa, Sb) include through holes (S11, S12) for the through insertion of fixing screws.

It is also envisaged that each of said half-shapes (Sa, Sb) also include transverse stiffening ribs (S4) placed in their concavity, to give greater rigidity and reduce the deformability of the shape (S) during the molding phases.

According to the embodiment shown in Figure 2, each half form (Sa, Sb) in turn comprises at least two sections (Sa1, Sa2; Sb1, Sb2) which can be coupled together to form the half form (Sa, Sb), and where each section (Sa1, Sa2) of the first half form (Sa) can also be coupled to the corresponding section (Sb1, Sb2) of the second half form (Sb).

In particular, each half-shape (Sa, Sb) comprises a first anterior section (Sa1, Sb1), which substantially affects the anterior part of the half-shape (Sa, Sb), and a second rear section (Sa2, Sb2), which substantially affects the back of the half form (Sa, Sb).

As schematized in figure 2a, the shape (S), obtained by coupling the corresponding anterior (Sa1, Sb1) and posterior (Sa2, Sb2) sections of each half-shape (Sa, Sb), is therefore composed of a rear part (S2 ), formed by the two rear sections (Sa2, Sb2) coupled, and a front part (S1), formed by the two front sections (Sa1, Sb1) coupled.

As schematized in figures 3a and 3b, said sections (Sa1, Sa2) of each half-shape (Sa), each coupled to the corresponding section (Sb1, Sb2) of the complementary half-shape (Sb), are inclinable with respect to each other. The coupling surfaces (S51, S52) between each anterior portion (Sa1, Sb1) and the corresponding posterior portion (Sa2, Sb2) of the same semi-shape (Sa, Sb) are of corresponding shape and preferably curved so that each anterior portion (Sa1, Sb1) can substantially incline with respect to the corresponding rear portion (Sa2, Sb2) sliding on said coupling surfaces (S51, S52) along a trajectory lying on a plane substantially parallel to the median plane of the shape (S). The shape (S) is therefore substantially articulated, because the rotation of the front (S1) with respect to the back (S2) simulates the natural movement of a foot, where the toe (P) of the foot bends with respect to the heel (T) .

Said coupling surfaces (S51, S52) are also preferably shaped with grooves (S62) and / or projections (S61) suitable for guiding the reciprocal sliding and possibly limiting it, to prevent the two parts, front (S1) and rear ( S2), unwanted separating. These are the schematic modalities sufficient for the skilled person to realize the invention, consequently, in concrete application there may be variations without prejudice to the substance of the innovative concept.

Therefore, with reference to the above description and the attached tables, the following claims are expressed.

Claims (10)

CLAIMS 1. Shape (S) for shoe molds or shoe parts made of plastic material characterized by the fact of comprising two or more complementary pieces (Sa, Sb) made of metallic material and which can be coupled together exactly to create a last (S ) complete, and where said form (S) is internally hollow. 2. Shape (S) for molds of footwear or parts of footwear in plastic material, as per claim 1, characterized in that said pieces (Sa, Sb) are made of aluminum or its alloys. 3. Shape (S) for molds of footwear or parts of footwear in plastic material, as per claims 1, 2, characterized in that it comprises two complementary pieces or half forms (Sa, Sb), each of which is substantially one half of the shape (S), cut in width by a median plane (X) joining the rear area of the heel (T) with the anterior area of the toe (P), and where said semi-shapes (Sa, Sb) are hollowed out. 4. Shape (S) for molds of footwear or parts of footwear in plastic material, as per claims 1, 2, 3, characterized in that said half-shapes (Sa, Sb) can be linked together, in a removable or non-removable way , by welding along the perimeter edges and / or by using fastening means such as bolts or other. 5. Shape (S) for molds of footwear or parts of footwear in plastic material, as per claims 1, 2, 3, 4, characterized in that each of said half-shapes (Sa, Sb) comprise, on said perimeter edges, one or more seats (S21, S22) and / or reliefs (S31, S32) for exact coupling with reliefs (S31, S32) or seats (S21, S22) present on the perimeter edges of the complementary half form (Sb, Sa) and / or they comprise one or more through holes (S11, S12) made in corresponding positions for the through insertion of fixing screws of said shape (S). 6. Shape (S) for molds of footwear or parts of footwear in plastic material, as per claims 1, 2, 3, 4, 5, characterized in that each of said half-shapes (Sa, Sb) comprises one or more ribs stiffening transversals (S4) arranged in the concave part of the semi-forms (Sa, Sb) themselves. 7. Shape (S) for molds of footwear or parts of footwear in plastic material, as per claims 1, 2, 3, 4, 5, 6 characterized in that each of said half-shapes (Sa, Sb) comprises two or more sections (Sa1, Sa2; Sb1, Sb2) which can be coupled together to form the half form (Sa, Sb) itself, and where each section (Sa1, Sa2) of the first half form (Sa) can be coupled to the corresponding section (Sb1, Sb2 ) of the second half-shape (Sb). 8. Shape (S) for molds of footwear or parts of footwear in plastic material, as per claim 7, characterized in that each of said half-shapes (Sa, Sb) comprises a first front section (Sa1, Sb1), which involves substantially the anterior part of the half form (Sa, Sb), and a second posterior section (Sa2, Sb2), which substantially affects the posterior part of the half form (Sa, Sb), said anterior section (Sa1, Sb1) being inclinable with respect to the relative posterior section (Sa2, Sb2), and where the anterior sections (Sa1, Sb1) of the two half forms (Sa, Sb) can be coupled to form the anterior part (S1) of the form (S), while the posterior sections ( Sa2, Sb2) of the two half shapes (Sa, Sb) can be coupled to form the rear part (S2) of the shape (S), and where said front part (S1) is inclinable with respect to said rear part (S2). 9. Shape (S) for molds of footwear or parts of footwear in plastic material, as per claims 7, 8, characterized in that the coupling surfaces (S51, S52) between said portions (Sa1, Sa2; Sb1, Sb2) of the same half form (Sa, Sb) are curved in such a way that the front part (S1) of the form (S) can tilt with respect to the rear part (S2) of the form (S) sliding on said coupling surfaces (S51, S52) along a trajectory lying on a plane substantially parallel to the median plane (X) of the shape (S). 10. Shape (S) for molds of footwear or parts of footwear in plastic material, as per claims 7, 8, 9, characterized in that the coupling surfaces (S51, S52) between said between said portions (Sa1, Sa2; Sb1, Sb2) of the same half shape (Sa, Sb) comprise grooves (S62) and / or projections (S63) designed to guide and limit the sliding between said front part (S1) and said rear part (S2).