EP2952113A1 | 2015-12-09 | |||
FR2493112A1 | 1982-05-07 | |||
CA2854683A1 | 2015-12-19 |
CLAIMS 1. Process for making footwear in general or parts of footwear items (100, 110) in a polymeric material, characterized in that it comprises the following steps: preparing at least one last (3) serving as a counter mould, said last (3) being provided with at least one valve (10, 10', 10") which is coupled with said last (3) in a removable or non-removable manner; applying at least one outer covering portion (52) directly/indirectly constrained to said last (3); positioning said last (3) in said mould (2, 21), in such a way as to form at least one cavity (4) between said last (3) and said outer covering portion (52), in which the polymeric material can be injected in order to obtain an upper (110), and wherein said at least one valve (10, 10', 10") is located at the level of the point of injection (A) of the polymeric material and is incorporated inside said at least one outer covering portion (52); - closing the mould (2, 21); injecting a polymeric material in said at least one cavity (4) through said at least one valve (10, 10', 10") which in turn is provided with at least one mouth or opening (13, 13', 13") for the injection of the polymeric material and one or more channels or openings (14, 14', 14") obtained inside said valve (10, 10', 10") and communicating with the inside of said at least one cavity (4); opening the mould (2, 21) and extracting the footwear item or part of footwear item (100, 110) obtained. 2. Process according to claim 1, characterized in that it also comprises the step of application of an inner lining portion (51) to said last (3), wherein said first inner lining portion (51) is without openings. 3. Process according to claim 1 or 2, characterized in that said at least one valve (10, 10', 10") is applied to said last (3) in a non- removable manner, being integrated in or in any way sealed to the last (3) itself. 4. Process according to claim 1, characterized in that said at least one valve (10, 10', 10") is applied to said last (3) in a removable manner, so that detaching said last (3) from the obtained footwear item or part of footwear item (100, 110) means detaching said valve (10, 10', 10") from said last (3), and wherein said valve (10, 10', 10") remains inside the upper (110) obtained. 5. Process according to claim 2, characterized in that said at least one valve (10, 10', 10") is applied to said last (3) in a removable manner after said step of application of said inner lining portion (51) to the last (3), so that, once said valve (10, 10', 10") has been applied, said inner lining portion (51) is positioned and held between said last (3) and said valve (10, 10', 10"), and wherein detaching said last (3) from the footwear item or part of footwear item (100, 110) obtained means detaching said valve (10, 10', 10") from said last (3), so that said valve (10, 10', 10") remains inside the upper (110) obtained, included between said inner lining portion (51) and said outer covering portion (52). 6. Process according to any of the preceding claims, characterized in that it also comprises the step of injection of a sole or tread (120) inside at least one cavity (41) provided in said mould (2, 21), and wherein said injection step is carried out before or after said step of injection of said upper (110). 7. Equipment implementing the process according to any of the preceding claims, comprising at least one mould (2, 21) and at least one last (3) which are suited to define, between them, at least one cavity (4) for the injection of the polymeric material, characterized in that said last (3) comprises at least one valve (10, 10', 10") constrained to it in a removable or non-removable manner, said valve (10, 10', 10") in turn comprising a body provided with at least one mouth or opening (13, 13', 13") for the introduction of the polymeric material to be injected, and one or more channels or openings (14) located inside said body and communicating with the outside, and wherein said valve (10, 10', 10") is positioned on said last (3) in such a way that said mouth or opening (13) is located at the level of the point of injection (A) of the polymeric material, while said channels communicate with the inside of said at least one cavity (4). 8. Equipment according to claim 7, characterized in that said valve (10) is constrained to said last (3) in a removable manner, said last (3) comprising at least one projection or seat (31) suited to be removably coupled with a corresponding seat (16) or projection provided on said valve (10), which in turn comprises a body having: a first side (11) suited to be placed against said last (3) and provided with a seat (16) or projection suited to be coupled with said projection or seat (31) created on the last (3) itself; a second side (12) substantially opposite said first side (11) and intended to be facing towards the point of injection (A) of the mould (2, 21); at least one injection mouth (13) through which the molten polymeric material is injected, said mouth (13) being obtained in said second side (12); one or more channels (14) created in the body of the valve (10), communicating with said at least one mouth (13) and having outlets (15) on the sides of the valve (10), said outlets (15) being intended to be facing towards the inside of the cavity (4), and wherein said polymeric material injected in the valve (10) reaches said cavity (4) through said channels (14). 9. Equipment according to the preceding claim, characterized in that said valve (10) comprises also channels or recesses or projections (17) in general suited to increase the grip of the polymeric material on the valve (10), which thus is held inside the cavity (4) once the moulding operation has been completed. 10. Equipment according to claim 7, characterized in that said valve (10') is constrained to said last (3) in a removable manner and comprises: a first side (1 Γ) suited to be placed against said last (3) and provided with said seat (16) suited to accommodate a corresponding projection (31) created on said last (3); a second opposite side (12') which is substantially concave, meaning provided with a recess (13') in which the polymeric material is injected and which communicates with channels (14') or openings in turn communicating with the inside of the cavity (4) where the upper (110) is injected. 11. Equipment according to claim 7, characterized in that said valve (10') is constrained to said last (3) in a non-removable manner and comprises a substantially cylindrical body whose first side (11") placed against said last (3) is substantially annular in shape, and wherein the material injected in the cylindrical body through its lower open end or mouth (13") flows into the cavity (4) where the upper (110) is injected through openings or channels (14") made in the cylindrical wall of said cylindrical body. 12. Footwear item or part of footwear item (100, 110) obtained from the process implemented according to one or more of claims from 1 to 6, comprising at least one upper (110) made of a polymeric material and obtained from an injection operation and at least one outer covering portion (52) for said upper (110). 13. Footwear item or part of footwear item (100, 110) according to the preceding claim, characterized in that it comprises also an inner lining portion (51) for said at least one upper (110). |
AND ITEM OBTAINED THEREWITH
DESCRIPTION
The present patent concerns the methods and equipment for the production of footwear made of a polymeric material, and in particular it concerns a new process for making footwear or parts of footwear items from a polymeric material, an apparatus for implementing said process and the item obtained therewith.
Various types of objects made of a polymeric material, among which boots and footwear in general, protection elements for sports, bags, etc., are currently known. For example, waterproof footwear items, such as boots, are known, which comprise an upper generally constituted by a single piece obtained through an injection moulding process.
Said footwear item is produced using an inner last on which a first portion of fabric, which will constitute the inner lining of the shoe, is fitted. Said last with the first portion of fabric fitted thereon is introduced in the mould, made up of several elements, among which lateral rings and a lower closing bottom, and wherein a cavity is defined between the rings, the last and the bottom, in which the polymeric material for the production of the upper and possibly of the tread will be injected.
Once the mould has been closed, the polymeric material is injected in said cavity, between said first portion of fabric applied to the last and the sides of said mould. Footwear items are also known which, in addition to the inner lining, are provided with an outer covering.
According to the known technique, for the application of said outer covering a second portion of fabric or cloth or another material is applied to the inner sides of the mould, in such a way that the cavity in which the polymeric material will be injected is included between the first lining portion and the second covering portion. Said second covering portion is generally provided with at least one hole or opening for communication with the injection channel, through which the polymeric material is injected in said cavity.
It is known that spacer blocks or valves constrained to the last are used to keep the last itself spaced from the second fabric covering portion. At least one of said blocks is generally positioned at the level of the injection point, and comprises at least one mouth which, through one or more channels obtained in the block itself, communicates with the inside of said cavity. The molten polymeric material coming from the injection channel is injected through said mouth and through said channels, in such a way that it reaches the inside of the cavity.
Owing to the presence of said blocks, said first fabric portion or lining portion in general is provided with at least one opening made at the level of each block.
At the moment of positioning said fabric lining portion, it is necessary to pay the utmost attention in order to ensure that the edges of the opening perfectly coincide with the edges of the block.
Analogously, also said second fabric portion or covering portion in general is provided with at least one hole at the level of said mouth of the block.
A drawback posed by this type of process and equipment is represented by the fact that, in order to be able to open the mould and remove the last, it is necessary that, as already explained, said first fabric portion or lining portion be holed at the level of the block.
Therefore, there is the problem of correctly positioning said lining and covering portions on the last and in the mould.
At the moment of injection through the block, the molten polymeric material flows through the block and out of the channels, gradually filling the mould cavity. The molten material can penetrate through the hole made in said first fabric portion or lining portion and be interposed between the last and the fabric lining portion itself. In this case, the product obtained in this way requires a further finishing operation which consists in the removal of the excess plastic material.
A further drawback is represented by the waste of polymeric material.
In order to overcome all the drawbacks described above, a new process for making footwear or parts of footwear items in general from a polymeric material has been designed and developed, together with an apparatus for the implementation of said process and the item obtained therewith.
The main object of the present invention is to resolve the problems illustrated above. Within the main object stated above, an important aim of the present invention is to provide a process that is simplified compared to the processes described above, in particular with reference to the positioning of the spacer blocks and the fabric covering and lining portions and to the extraction of the product from the mould. It is another object of the present invention to provide a process that makes it possible to manufacture objects with greater precision, thus limiting the successive finishing operations and the need to remove the excess material.
These and other direct and complementary objects are achieved by the new process for making footwear or parts of footwear items from a polymeric material, the apparatus for the implementation of said process and the item obtained therewith. The new process includes the following steps:
preparing at least one last serving as a counter mould, said last being provided with at least one spacer block or valve;
if required, applying a first fabric portion or inner lining portion to said last, wherein said lining portion is not provided with any opening;
applying a second fabric portion or outer covering portion to said last;
placing said last in said mould in such a way as to form at least one cavity between said last and the sides of the mould, in which the polymeric material for the production of the upper can be injected, and wherein said at least one valve is located at the level of the point of injection of the polymeric material; closing the mould; injecting a polymeric material in said at least one cavity between said last and said second outer covering portion through said at least one valve, in turn provided with at least one mouth for the injection of the polymeric material and with one or more channels or openings communicating with the inside of said at least one cavity;
opening the mould and extracting the last from the upper which has been obtained.
Said valve can be constrained to said last in a non-removable manner, for example sealed to it in any way or integrated into it.
Alternatively, said valve can be constrained to said last in a removable manner. In this case, the process comprises the further step of applying said valve to said last, wherein said application step takes place after said possible step of application of said first inner lining portion.
In the latter case, furthermore, the extraction of the last from the upper that has been obtained may involve the removal of said valve, which remains buried in said upper. As an alternative, the process may include a further step for the removal of the valve from the inside of the upper after the extraction of the last from the upper. If the upper obtained is provided with said inner lining portion, it is also necessary to make an opening in said inner lining portion, so that said valve can be extracted and thus used again.
The equipment designed to implement the new process thus comprises at least one mould and at least one last which are suited to define, between them, at least one cavity for the injection of the polymeric material, and wherein said last is provided with at least one projection or seat suited to be removably coupled with at least one block, said block in turn comprising a body provided with at least one mouth for the introduction of the material to be injected, and one or more channels located inside said body and communicating with the outside, and wherein said block is positioned on said last in such a way that said mouth is located at the level of the point of injection of the polymeric material, while said channels communicate with said cavity.
The footwear item or part of footwear item obtained from the process illustrated above comprises at least one body made of a polymeric material and obtained from an injection process as described above, wherein said body comprises an upper, possibly with a tread or sole constrained thereto, and at least one outer covering.
The footwear item furthermore may comprise at least one inner lining portion for said upper, a tread or sole and said valve buried into said upper.
The characteristics of the present invention are highlighted in greater detail in the following description with reference to the attached drawings, which are enclosed hereto by way of non-limiting example.
Figures 1 and 2 respectively show a sectional view and a view of the upper side (11) of a valve (10).
Figure 3 shows a schematic sectional view of the equipment (1), at least one mould (2, 21), at least one last (3), wherein a cavity (4) is defined between said sides (22) of the mould (2, 21) and said last (3), at least one outer covering portion (52) applied to the last (3) and free in said cavity, in such a way that the injection of the polymeric material takes place in said cavity between the last (3) and said outer covering portion (52).
Figure 3 a shows in detail the position of the valve (10).
Figure 4 shows a schematic sectional view of the equipment (1), at least one mould (2, 21), at least one last (3), a further inner lining portion (51) applied to the last (3) and an outer covering portion (52), and wherein a cavity (4) for the injection of the upper (110) is defined between said inner lining portion and said outer covering portion (51, 52).
Figure 4a shows in detail the position of the valve (10) on the inner lining portion (51).
Figure 5 shows a schematic sectional view of the equipment (1), at least one mould (2, 21), at least one last (3), an outer covering portion (52), and wherein a cavity (4) for the injection of the upper (110) is defined between said last (3) and said outer covering portion (52).
Figure 5a shows in detail a possible second embodiment of a valve (10').
Figure 6 shows a schematic sectional view of the equipment (1), at least one mould (2, 21), at least one last (3), an outer covering portion (52), and wherein a cavity (4) for the injection of the upper (110) is defined between said last (3) and said outer covering portion (52).
Figure 6a shows in detail a possible third embodiment of a valve (10").
Figure 7 shows a schematic view of a footwear item (100) manufactured with the process implemented according to the present invention.
The new process comprises at least one step of injection of a polymeric material into a mould, more precisely into at least one cavity (4) defined between the sides (22) of a mould (2, 21) and a last (3).
The last (3) is generally shaped in such a way as to reproduce the concave part of the footwear item (100) to be obtained.
Before said injection step, the process comprises the optional step of application of a first inner lining portion (51) to said last (3), wherein said first portion (51) is without openings.
Said last (3), if required covered by said inner lining portion (51), comprises at least one valve (10) located at the level of the point of injection (A) of the polymeric material.
In the solution illustrated in Figures 1, 2, 3a, 4a, in order to guarantee the correct positioning of the valve (10) on said last (3), the last (3) is provided with at least one projection (31) suited to be inserted in a corresponding seat (16) created in said valve (10).
According to an alternative embodiment not illustrated herein, said last (3) may comprise at least one seat suited to accommodate a projection created on said valve (10).
Said valve (10) can thus be constrained to said last (3) in a removable manner, possibly with said inner lining portion (51) interposed therebetween. For this purpose, said inner lining portion (51) is flexible, so that it can be deformed and maintained correctly positioned between said last (3) and said valve (10), with no need to be perforated.
In a possible solution, said block (10) is, for example, of the type shown in Figures 1 and 2, where it is substantially disc-shaped, circular in plan view. According to the invention, however, also depending on the type and shape of the mould (2, 21) or of the last (3) used, said valve (10) can have any shape, for example elliptic or oval, triangular, rectangular or polygonal in general.
In general, said valve (10) comprises a body having a first side (11) suited to be placed against said last (3) and provided with said seat (16) or projection suited to allow it to be coupled with the last (3).
The second side (12) of said valve (10), substantially opposite said first side (11), is intended to be facing towards the injection point (A) of the mould and comprises at least one injection mouth (13) through which the molten polymeric material is injected.
Said mouth (13) communicates with one or more channels (14) or openings obtained in the body of the valve (10) and provided with outlets (15) located on the sides of the valve (10) and intended to be facing towards the inside of the cavity (4).
Said polymeric material injected in the valve (10) reaches said cavity (4) through said channels (14) or openings.
Said valve (10) comprises also channels or recesses or projections (17) in general suited to increase the grip of the polymeric material on the valve (10) itself, which is thus held inside the cavity (4) once the moulding operation has been completed.
Alternatively, according to the invention said at least one valve (10) can be constrained to said last (3) in a non-removable manner, for example being sealed to the last in any way or integrated in the last (3) itself.
The process includes also the application of a second outer covering portion (52) to said last (3), which remains free in said cavity (4), so that said at least one cavity (4) is defined between said last (3), possibly with an inner lining portion (51), and said outer covering portion (52).
Once the mould has been closed and the polymeric material has been injected into said at least one cavity (4), the upper (110) is obtained.
The process may include the further step of injection of the sole or tread (120) of the footwear item, consisting in the injection of a polymeric material into a cavity (41) provided in said mould (2, 21), and wherein said step of injection of said sole or tread (120) can take place before or after the injection of the upper (110).
Once the injection operations have been completed, the mould can be opened and the footwear item (100) obtained is extracted.
The obtained footwear item (100) is extracted by removing the last (3) and detaching the same from the upper (110).
In the case where said valve (10) is constrained to said last (3) in a removable manner, detaching the last (3) from the upper (110) means detaching said valve (10), which thus remains buried into the upper (110).
According to the invention, said valve (10) can be removed from the upper (110) from the inside of the upper (110) itself.
In the case where the inside of the upper (110) is lined with said inner lining portion (51), it is possible to remove said valve (10) after cutting and making an opening in said inner lining portion (51), in a corresponding position.
Said footwear item (100) obtained with the process described above thus comprises at least one upper (110) in a polymeric material, obtained from an injection process as described above, a possible first inner lining portion (51) for said upper (110), a second outer covering portion (52) for said upper (110), a possible sole or tread (120), and wherein said at least one valve (10) of the type described above can be buried inside said upper (110) made of a polymeric material.
According to the description provided above, the new process facilitates the correct positioning of the valves (10).
Consequently, the process itself is simplified, as the inner lining portion (51) can be positioned in a more straightforward manner, with no need to perforate it before the injection operation.
The presence of said projection or seat (31) on said last (3), in fact, makes it possible to identify the correct position for the application of the valve (10) in a safe, stable and straightforward manner.
In fact, it is sufficient to fit the inner lining portion (51) on the last (3) and then apply the valve (10). In this manner, not only is the first lining portion (51) maintained in position, but its correct stretching is also guaranteed.
Furthermore, there is no risk of the polymeric material flowing out through said inner lining portion (51) and the last (3) in an uncontrolled manner during the injection step. There is no waste of material and no further finishing operations are required to remove the excess material from the finished item.
With reference to Figures 5 and 5a, said valve (10') comprises a first side (1 Γ) suited to be placed against said last (3) and provided, for example, with said seat (16') for the insertion of a corresponding projection (31) provided on said last (3).
The opposite side (12') can be substantially concave, meaning provided with a recess
(13') in which the polymeric material is injected and which communicates with channels (14) or openings in turn communicating with the inside of the cavity (4) where the upper (110) is injected.
In the embodiment illustrated in Figure 6, said valve (10") has a substantially tubular body, for example cylindrical, wherein the first side (11") placed against said last (3) is substantially annular in shape, and wherein the polymeric material injected into the cylindrical body through its lower open end or mouth (13") flows into the cavity (4) where the upper (110) is injected through openings or channels (14") created in the cylindrical wall of said cylindrical body.
Said embodiment of the valve (10") is particularly useful if the valve (10") is integrated in or integral with the last (3) in a non-removable manner, so that, once the injection has been completed and the mould opened, said last (3) can be extracted together with the valve (10"), leaving a substantially cylindrical hole in the upper.
These are the schematic outlines which are sufficient for the expert in the art to implement the invention, consequently upon practical application variants may be developed which do not depart from the innovative substance of the concepts introduced herein.
Therefore, with reference to the above description and the attached drawings, the following claims are expressed.