ITMI20130160A1 - APPARATUS FOR MOLDING SOLES AND VARIOUS ITEMS IN PLASTICS - Google Patents

Description

DESCRIPTION

APPARATUS FOR MOLDING SOLES AND VARIOUS PLASTIC ARTICLES TECHNICAL FIELD OF THE INVENTION

The present invention relates to an apparatus or plant for molding shoe soles and various articles made of plastic, for example saddles and saddles of bicycles and two-wheeled vehicles, sandals, technical articles, all mainly developed in length, as specified in the preamble of the first claim. The apparatus is also of the type which includes a conveyor equipped with molds in correspondence with which pouring or extrusion operations of the material making the soles and said various articles are carried out.

DESCRIPTION OF THE KNOWN ART

As is known, the soles of footwear - as well as saddles and other articles - are in many cases made using special equipment or very complex systems that include a conveyor - also called a carousel - which transports along a closed path, for example circular or rectangular or elliptical or other, a large number of consecutive and adjacent molds.

The molds are made to pass - by means of an intermittent advancement - in the vicinity of dispensing stations of materials making up the soles or other articles, where they stop to be fed, for example, by liquid bicomponent polyurethanes (PU) or thermoplastic polyurethanes (TPU) or from thermoplastic rubber.

Depending on the material, dispensing stations are provided for performing casting or extrusion.

The soles of the footwear - as well as the saddles and other articles - which carry out the typical use of the apparatus, are printed in isolation and applied for example by gluing or sewing to the uppers. They can then have a simple structure, or be associated with inserts, have various colors, etc., depending on how the dispensing stations are arranged and controlled.

The soles - as well as the saddles and other articles - have as their universal feature an axial line with a prevalent development, from the heel to the toe, and consequently the molds for the same generally have a footprint that develops mainly in sense parallel to the soles.

Therefore, they have a substantially rectangular plan shape, with the prevailing sides in correspondence with the sides of the soles and the shorter sides in correspondence with the ends of the soles.

The molds are arranged side by side at their main sides, so that the length of the closed path of the conveyor is substantially or mainly defined by the shorter sides of the same.

In the case of a circular path, the molds develop radially to the path itself.

In any case, beyond the shape of the molds, which can be very complex, the cavities provided in them are arranged radially, in the presence of a circular path, or in any case transversely to their direction of advancement, to contain the overall dimensions in the direction of movement of the conveyor.

In this situation the known apparatuses or machines or plants that make the soles operate - with reference to the main work phases - in the following way.

The conveyor is moved so as to bring each mold in succession to a position close to the dispensing station.

In the vicinity of the station, the mold is opened and when the position of maximum proximity is reached, the movement of the mold is stopped and the dispensing station delivers the liquid polyurethane or thermoplastic polyurethane or rubber or other into the cavity of the open mold.

To do this, in the presence of a prevalent development of the said cavity directed transversely to the advancement, the injector of the dispensing station is made to move transversely to the conveyor, towards its center in the case of a circular profile of the same, so as to dispense the sole material along the entire length of the sole, from heel to toe or vice versa. In practice, the injector performs a to and fro movement.

When dispensing is complete, the injector is brought back to the starting position, the conveyor moves to bring another mold to the dispensing station and the already filled mold is closed.

In the closed mold, the dispensed material crosslinks and solidifies and after a certain time from closing, generally a few minutes, it is possible to reopen the mold and extract the sole or other molded article.

Then the conveyor returns the mold to the dispensing station.

The aforementioned known technique has some important drawbacks.

A drawback is connected to the to and fro movement of the injector - or of the dispensing station - to dispense the material along the entire length of the sole or of the plastic article being formed. The movement must be precise and fast and this determines a complex realization of the dispensing station.

Another drawback is connected to the continuous stops and starts of the conveyor, which require a sturdy construction of the same and its organs.

A further drawback can be found in the relative slowness of the apparatus, which must accept continuous stops and also a relative delay in closing the mold covers, to avoid interference between the mold covers and the plastic injector.

Not the least drawback is the high cost and the relative delicacy of the whole apparatus, which must operate with maximum precision and in the presence of complex movements and synchronizations.

SUMMARY OF THE INVENTION

In this situation, the technical task underlying the present invention is to obviate the aforementioned drawbacks.

Within the scope of said technical task, it is an important aim of the invention to devise an apparatus or plant for molding soles - and various articles in plastic material mainly developed in length - with a simple structure and able to operate without requiring difficult movements. to the constituent bodies of the same.

Another important object is to devise an apparatus in which the phases of introducing material into the molds take place quickly and easily.

A further object of the invention is to provide a relatively inexpensive apparatus or plant that can be used for large production levels.

Not the least object of the invention is to devise an apparatus capable of carrying out an efficient and simple molding process.

The said technical task and the specified aims are achieved by an apparatus for molding soles and various articles in plastic material, as claimed in the attached Claim 1.

Preferred embodiments are highlighted in the sub-claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics and advantages of the invention are clarified below by the detailed description of a preferred embodiment thereof, with reference to the accompanying drawings, in which:

- Fig.1 shows a schematic and plan view of the apparatus with reference to relevant components for the present invention;

- Fig.2 shows in plan and on an enlarged scale a detail of the previous figure; And

- Fig. 3 is an elevation view of the portion of the apparatus identified by the section line III - III of Figure 1.

DETAILED DESCRIPTION OF THE PREFERRED REALIZATION

With reference to the Figures, the apparatus or plant according to the invention is globally indicated with the number 1. It is intended for the molding of shoe soles and for the molding of various articles in plastic material mainly developed in length,

In its preferred execution, highlighted in the drawings, the apparatus 1 is aimed at the formation of soles, one for each mold, alternating a left sole with a right sole or creating first a series of left soles and then right ones, or vice versa.

As shown in Fig. 1, the apparatus 1 comprises a conveyor 2 - also called a carousel - developing along a closed path 2a and moving along said closed path 2a.

The conveyor 2 and the closed path 2a can develop parallel to each other according to a circumference, as in Fig. 1, or following a path with some rectilinear sections, for example substantially rectangular or substantially elliptical.

The conveyor 2 is associated with a plurality of molds 3, supported and translated by the conveyor itself, to which they are removably engaged.

These molds 3 are comprised of a base 3a and a lid 3b.

The base 3a can be removably inserted into the conveyor 2, which in this case substantially forms a rotating table.

This technical solution is the one illustrated in the Figures, where the conveyor 2 is a large rotating circular table.

The molds 3 have internally cavities or indentations 4 defining the geometry of the soles at the end of the molding operations.

The soles have a universally prevailing length over the width and therefore each cavity 4 has an axial line 4a with a prevalent development, which extends between the heel and the toe of the sole being formed, therefore corresponding to its length.

The conveyor 2 - or carousel or rotary table - passes in correspondence with at least one work station formed by a material dispensing station 5 in the cavities or cavities 4 of the molds. The material supplied can be, as known, a two-component liquid polyurethane (PU) or a thermoplastic polyurethane (TPU) or thermoplastic rubber or other.

Depending on the material chosen and its density, the dispensing station 5 acts by casting or by extrusion and the terminal element of the dispensing station can be an injector 6 or a corresponding terminal element, for example an extrusion mouth, a nozzle dispenser, a pouring element, etc. Several dispensing stations 5 can also be arranged and the molds 3 can also be made in such a way as to produce soles having inserts, layers of different densities, various colors, etc.

Appropriate control means known per se - including electronic, electrical, fluid-dynamic and mechanical devices - are then provided to make the apparatus1 operational, in particular to activate the work stations, synchronize operations, detect the correct functioning of all the elements, etc.

For example, advancement devices 1a are provided to guide and advance the conveyor 2, control devices 7 to open and close the molds 3, activation devices 8 to activate the dispensing station 5 and in particular the injector 6.

The feeding devices 1a of the conveyor 2 can comprise for example suitable tracks and / or a large support and guide base (Fig. 3) and specific electric motors.

The control devices 7 of the molds 3 are for example fluid-dynamic cylinders (Fig. 3) which operate in particular by opening and closing the lids 3a and extend towards the center of the conveyor 2.

The activation devices 8 are for example placed immediately upstream of the injector 6 (Fig. 3), are connected to pumping members and are substantially structured for example as a tap or the like.

According to the invention and as shown in Figs. 1 and 2, the axial line 4a with a prevalent development of each of the cavities 4 is advantageously arranged substantially concordant with the closed path 2a of the conveyor 2.

Preferably each cavity 4 is aligned with consecutive cavities 4 to define at least one molding trajectory 5a extending in accordance with the closed path 2a.

Another important aspect of the invention can be identified in the fact that the dispensing station 5 advantageously has the injector 6 substantially fixed, in the dispensing phase, transversely to the closed path 2a.

The injector 6 can be raised and lowered and obviously also translated in any direction during the preparation and maintenance phases, but during the molding it remains immobile in the direction transversal to the axial line 4a of each cavity 4 which is supplied with PU or TPU or thermoplastic rubber or other.

In particular, the illustrated dispensing station 5 has the injector 6 vertically surmounting the molding trajectory 5a and each single cavity 4, while the same is being refueled.

Obviously, if several cavities 4 are provided in each mold 3, for example two side by side, both are aligned with the consecutive cavities of the adjacent molds, so as to define two molding trajectories 5a side by side and parallel and both in agreement and parallel to the closed path 2a of the conveyor 2. In this case, two injectors 6 are provided side by side and each overlapping a molding trajectory 5a.

A further important aspect of the invention can be identified in the fact that, advantageously, the feeding devices 1a of the conveyor 2 are designed to give the conveyor 2 and the molds 3 a continuous movement and at substantially constant speed, along the closed path. 2a.

Therefore, the pause of the molds 3 at the dispensing station 5 is eliminated and the injector 6 is controlled by the activation devices 8 in an intermittent manner so as to dispense the molding material only when the individual cavities 4 pass.

Another advantageous aspect of the invention is connected to the fact that - due to the largely prevailing length of the soles, with reference to their width, and due to the said position of each cavity 4 - at least the lid 3a of each mold 3 comprises main sides substantially tangential and concordant with the closed path 2a of the conveyor 2.

This means that the cover 3a can be connected, by means of an articulation 9, for example a joint or a pin, to the base 3b in correspondence with a main side.

As a consequence of this situation, highlighted in Figs. 2 and 3, the cover 3a has a relatively small overall dimensions when lifted and less possibility of interference with the nozzle or injector 6.

The operation of apparatus 1, described above in a predominantly structural sense, is as follows.

The conveyor 2 moves the molds 6 bringing them, one after the other, to the dispensing station 5.

Here the molds do not interrupt their movement, but pass under the injector 6 maintaining their translation speed and placing themselves in the open position.

The injector 6 is activated intermittently, so as to deliver material only while a cavity 4 is below it.

It must therefore not move as the trajectory of the cavities 4 is strictly correlated to the position of the injector itself. Nor does it have to oscillate to deliver material along the entire direction of development of the cavities, as they gradually pass from the toe area to the heel area, or vice versa, below the injector.

The delivery can then take place in the most appropriate way, for example it can be greater at the heel and less at the tip of the sole being formed. In a similar way, the supply can be greater in correspondence with the widest part, for example of a bicycle saddle.

The closing of the lids of the molds can then take place immediately after the dispensing of the plastic material, to allow the material to reticulate and solidify, as the development of the lid in height is reduced and minimally interferes with the dispenser above.

The apparatus or plant 1 according to the invention realizes an original and advantageous molding process of soles and various articles in plastic material, for example saddles, sandals and technical articles mainly developed in length.

The procedure provides that each cavity or impression 4 provided for the formation of a sole is positioned aligned with consecutive cavities 4 to define at least one molding trajectory 5a developing in accordance with the closed path 2a and that - in combination - the dispensing station 5 is activated so as to generate a delivery trajectory developing in agreement with the closed path 2a.

Advantageously, the dispensing station 5 is kept substantially fixed in a transverse direction to the closed path 2a.

Originally, the molds 3 and the cavities 4 are translated with a continuous movement and at a substantially constant speed along the molding trajectory 5a and the dispensing station 5 is activated intermittently, in synchrony with the passage in the vicinity of a cavity 4.

Furthermore, the intermittent activation of the dispensing station 5 is performed in a manner suitable for dispensing a molding material by continuous portions, substantially corresponding to the length of each cavity 4, in the direction of the axial line 4a.

The invention achieves the proposed aims and allows important advantages.

In fact, the apparatus or plant 1 operates without requiring displacements to the dispensing station 5 and without making stops during the molding operations.

Therefore the organs of the apparatus 1 operate simply, quickly and without mechanical stress.

The molding is carried out with precision and the material that makes the sole is dispensed along the whole axial line 4a of prevalent development of the cavities 4 of the molds 3.

Due to the size and positioning of the lids 3a, it is also possible to close them immediately after dispensing the plastic material without interfering with the dispensing station 5. In this way the solidification quality of the material is improved and the product can be immediately started. itself.

The invention is susceptible of modifications and variations falling within the scope of the inventive concept.

All the elements described and claimed can be replaced by equivalent elements and the details, materials, shapes and dimensions can be any.

Claims (10)

CLAIMS 1. Apparatus (1) for molding soles and various articles in plastic material mainly developed in length, of the type comprising: a conveyor (2) movable and defining a closed path (2a); a plurality of molds (3) associated with said conveyor (2), said molds (3) having internally cavities (4) each of which is provided with an axial line (4a) with prevalent development; and at least one dispensing station (5) of plastic material in said molds (3); - the apparatus (1) being characterized by the fact that said axial line (4a) of said cavities (4) is arranged substantially in agreement with said closed path (2a). Apparatus (1) according to the preceding claim, wherein each of said cavities (4) is aligned with consecutive cavities (4) to define a molding trajectory (5a) developing in accordance with said closed path (2a). 3. Apparatus (1) according to one or more of the preceding claims, in which advancement devices (1a) are provided, suitable for imparting to said conveyor (2) and said molds (3) a continuous movement and at substantially constant speed along said closed path (2a). 4. Apparatus (1) according to one or more of the preceding claims, wherein said dispensing station (5) has at least one injector (6) substantially fixed during dispensing in a direction transversal to said closed path (2a). 5. Apparatus (1) according to one or more of the preceding claims, wherein said dispensing station (5) has said at least one injector (6) arranged vertically above said molding path (5a). 6. Apparatus (1) according to one or more of the preceding claims, wherein said molds (3) comprise a base (3b) and a lid (3a) having main sides alongside said closed path (2a), and in which said lid (3a) is articulated to said base (3b) in correspondence with one of said main sides. 7. Process for molding soles and various articles in plastic material mainly developed in length, in an apparatus (1) comprising: a conveyor (2); a plurality of molds (3) associated with said conveyor (2), said molds having cavities (4) internally each of which is provided with an axial line (4a) with prevalent development; and at least one dispensing station (5) of plastic material in said molds (3); - the process being characterized by the fact that each of said cavities (4) is aligned with consecutive cavities (4) to define at least one molding trajectory (5a), and by the fact that said dispensing station (5) is activated in mode adapted to generate a dispensing trajectory corresponding to said molding trajectory (5a). 8. Process according to the preceding claim, in which said dispensing station (5) is kept substantially fixed during dispensing and in which said molds (3) are translated with a continuous movement and at substantially constant speed along said molding trajectory (5a). 9. Process according to one or more of the preceding claims, in which said dispensing station (5) is activated intermittently, in synchrony with the passage in proximity of each said cavity (4). 10. Process according to one or more of the preceding claims, wherein said dispensing station (5) is activated intermittently in a manner adapted to dispense a molding material by continuous portions substantially corresponding to the length of each said cavity (4).