VERTICAL INJECTION MACHINE FOR MOLDING SOLES, TECHNICAL ARTICLES AND THE LIKE Technical Field

The present invention relates to a vertical injection machine for molding soles, technical articles and the like. Background Art

Vertical injection machines for molding soles, technical articles and the like are currently known.

The injected molding material is generally thermoplastic material, rubber, ethyl vinyl acetate, and the like.

These known machines generally comprise a supporting footing, which supports a plurality of presses which have a vertical closing motion and are provided with mold holders for supporting corresponding molds; the molds are fed by at least one injection assembly, which is arranged above the presses in order to inject substantially vertically.

Means for the mutual relative motion of the injection assembly and of at least portions of the molds are present.

In these known machines, the presses and the corresponding mold holders are arranged along two parallel and longitudinally adjacent rows, so as to be smaller and more compact, for an equal number of presses, than known molding machines with horizontal injection.

Although this layout has the great advantage of allowing operators to avoid hindering each other in accessing the machine, it is however rather awkward when it is necessary to access the molds for siliconizing, cleaning and other similar maintenance operations, since with this configuration each mold can be accessed from only one side. Disclosure of the Invention

The aim of the present invention is to provide a vertical injection machine for the injection-molding of soles, technical articles and the like, which is capable of obviating the drawbacks revealed by known types of

machine.

Within this aim, an object of the present invention is to provide a vertical injection machine which allows operators to avoid hindering each other in accessing the machine and at the same time facilitates access from both sides for cleaning and maintenance operations.

Another object of the present invention is to provide a vertical injection-molding machine which can be set up to obtain multicolored products.

Another object of the present invention is to provide a vertical injection machine for molding soles, technical articles and the like which can be manufactured cheaply with known systems and technologies.

This aim and these and other objects, which will become better apparent hereinafter, are achieved by a vertical injection machine for molding soles, technical articles or the like, of the type which comprises a footing which supports a plurality of presses which have a vertical closing motion and are provided with mold holders for supporting corresponding molds, said molds being fed by at least one injection assembly arranged above the presses in order to inject substantially vertically, means being provided for the relative mutual motion of said vertical injection assembly and of at least portions of said mold holders, said machine being provided with a control and actuation assembly arranged adjacent to the presses, said machine being characterized in that said presses, with said respective mold holders, are arranged in a line and are mutually adjacent, so as to form a single row, so that they can be accessed from both sides, said relative motion means being constituted by longitudinal guides which are fixed so as to lie above laterally adjacent modular frameworks, each of which supports at least one press, a slider which supports said vertical injection assembly being arranged on said guides so that it performs a translational motion by means of motorization means.

Brief Description of the Drawings

Further characteristics and advantages of the invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a perspective view of a machine according to the invention;

Figure 2 is a side view of a machine according to the invention;

Figure 3 is a view of a first step of a molding operation performed with a machine according to the invention;

Figure 4 is a view of a second step of a molding operation performed with a machine according to the invention;

Figure 5 is a view of a third step of a molding operation performed with a machine according to the invention; Figure 6 is a view of a fourth step of a molding operation performed with a machine according to the invention;

Figure 7 is a view of a detail of the side view of Figure 2. Ways of carrying out the Invention

With reference to the figures, a vertical injection machine for molding soles, technical articles and the like according to the invention is generally designated by the reference numeral 10.

The machine 10 comprises a footing 11, which supports a plurality of presses 12 which have a vertical closing motion.

The presses 12 are provided with mold holders for supporting corresponding molds 14.

The mold holders are constituted by a lower mold part holder 13a or 13c and by an upper mold part holder 13b.

The mold part holders are fed by an injection assembly 15, which is arranged above the presses 12 in order to inject substantially vertically. The vertical injection assembly 15 is moved with respect to the molds

14 by way of relative movement means, described in greater detail hereinafter.

The machine 10 is provided with a control and actuation assembly 16, which is located adjacent to the presses 12 in order to actuate their operation.

The presses 12 and the corresponding mold holders, together with the corresponding molds 14, are arranged in a line and are adjacent so as to form a single row 17, so that they can be accessed from both sides.

The control and actuation assembly 16 is arranged at the front of one of the two ends of the row 17 of presses 12.

In the embodiment of machine 10 according to the invention described here by way of non-limiting example, the injection assembly 15 is provided with two injectors 15a and 15b, which are longitudinally adjacent, for molding two-color products. The machine 10 according to the invention is constituted by at least two modular frameworks 20, each of which supports at least one pair of presses 12.

Each one of the frameworks 20 comprises a portion 11a or l ib or l ie of the footing 11, from which a frame 21 for supporting two pairs of presses 12 rises.

The upper mold part holders 13b of such mold holders are arranged above the frame 21.

Each press 12 comprises a hydraulic actuator 18a and 18b, which is adapted to produce an upward clamping force for the closure of the lower mold part 14a against the corresponding upper mold part 14b of a mold 14.

The stem 19a or 19b of the hydraulic actuator 18a or 18b supports a lower mold part holder 13a for a lower part 14a of a mold 14.

The respective upper mold part 14b is rigidly coupled to its own upper mold part holder 13b, which in turn is rigidly coupled to the upper part of the frame 21 of the corresponding framework 20.

The upper mold part holder 13b is provided with a through opening 22 for each one of the nozzles of the injectors 15a and 15b of the vertical injection assembly 15.

Each one of the openings 22 allows an injection nozzle of one of the injectors 15a and 15b to rest directly on an associated underlying mold 14.

In the present exemplary embodiment of the invention, each one of the upper mold part holders 13b supports four upper mold parts, i.e., two pairs of upper mold parts 14b and 14c, the function of which is described in greater detail hereinafter. The machine 10 according to the invention, in the embodiment described here by way of non-limiting example, comprises three of the at least two modular frameworks 20, arranged in a line so as to form the row 17 of presses 12.

In a further embodiment, not shown for the sake of simplicity, the machine 10 comprises four of the at least two modular frameworks 20, arranged in a line.

The relative movement means are constituted by longitudinal guides 23, which are fixed above the mold holders 13b so as to lie above the laterally adjacent modular frameworks 20. A slider 24 which supports the vertical injection assembly 15 is arranged on the guides 23 so that it can perform a translational motion by way of motor drive means.

The motor drive means are constituted by an electric gearmotor 25, which is rigidly coupled to the slider 24 and is adapted to turn a pinion which meshes with a rack 26 which runs along one of the guides 23.

In a different embodiment of the machine 10 according to the invention, the injection assembly 15 can be made to perform a translational motion transversely to the direction of motion of the slider 24.

Figure 7 illustrates the injection assembly 15 supported by an additional second slider 24a, which is arranged so as to perform a

translational motion transversely on the first slider 24, the translational motion being obtained by means of a hydraulic actuator, which is not shown.

The second slider 24a is provided with sliding blocks 24b, which are arranged so as to slide on underlying rails 24c, which are rigidly coupled to the first slider 24.

The transverse translational motion of the injectors allows to perform two injections in the same mold, in order to achieve better filling of the impressions. This transverse translational motion is particularly important if the machine according to the invention is provided with three injectors for producing two- or three-color products; the injectors are adapted to perform a transverse translational motion in order to alternate with one another at the injection during a same molding cycle. In the exemplary embodiment of the machine 10 according to the invention described here, each pair of paired presses 12 cooperates so as to form a station 27 for molding two-color products made of EVA (ethyl vinyl acetate).

Each framework 20 therefore comprises two molding stations 27 arranged side by side.

Each station 27 for molding two-color products made of EVA comprises in turn:

- a first lower mold part holder 13 a, which is supported by the stem 19a of a first actuator 18a, and a second lower mold part holder 13c, which is supported by the stem 19b of the second adjacent actuator 18b;

- a first lower mold part 14a, to be accommodated alternately in the first mold part holder 13a and in the second mold part holder 13c;

- means, described in greater detail hereinafter, for transferring molds from the first mold part holder 13a to the second mold part

holder 13 c, and vice versa;

- a second upper mold part 14b, for closing the first mold part 14a when it is arranged on the first mold part holder 13a, so as to form a first impression for molding a first portion of a two-color product to be obtained;

- a third mold part 14c, which is also an upper mold part, for closing the first mold part 14a arranged on the second mold part holder 13c so as to form a second impression for the overmolding of a second portion of such two-color product to be obtained. Each molding station 27 comprises heating means, of a known type and not shown for the sake of simplicity, for example of the immersion heater type or of the type with channels and interspaces, within which a heating fluid flows, adapted to bring the impression formed by the first mold part 14a and the third mold part 14c to the cross-linking temperature of EVA, and cooling means, also known and not shown, for bringing the temperature of the first mold part 14a from the levels useful for the cross- linking of EVA, reached between the third mold part 14c and the second mold part holder 13 c, to the medium-low temperature interval adapted to perform a subsequent new injection of EVA for molding a new first portion of an additional two-color product to be obtained.

In the embodiment of the machine 10 described here by way of non- limiting example of the invention, the means for transferring the first mold part 14a from the first lower mold part holder 13a to the second laterally adjacent lower mold part holder 13c and vice versa are constituted by a linear actuator 28.

The linear actuator 28 can be selectively of the hydraulic, pneumatic, electric or equivalent type.

In the present exemplary embodiment, the linear actuator 28 is a hydraulic cylinder. The stem 29 of the cylinder moves, along a guide 30, a slide 31,

which supports a fork 32 for gripping a protrusion 33 which protrudes laterally from the first mold part 14a.

The operation of a station 27 for molding products made of two-color EVA is as follows. In a first step, shown schematically in Figure 3, the first mold part 14a is arranged on the first lower mold part holder 13a; the actuator 18a pushes upward the first mold part 14a, which closes against the second upper mold part 14b, so as to form the mold 14; the protrusion 33 of the first mold part 14a is free to leave the fork 32. The first mold part 14a and the second mold part 14b, closed so as to form the mold 14, are cooled to a temperature below the melting point of the plastic material to be injected.

The EVA of a first color is injected at the end of the cooling process.

Figure 4 illustrates schematically the first injector 15a, lowered so as to pass with its nozzle through the upper mold holder 13b in order to inject into the mold 14 the EVA so as to form a first impression for molding a first portion of a two-color product to be obtained.

When the first mold part 14a is lowered, the first portion remains rigidly coupled to the first mold part 14a. When the stem 19a of the first actuator 18a has returned the first lower mold part holder 13a to the height of the second lower mold part holder 13c, the first mold part 14a is engaged by means of the protrusion 33 by the fork 32 and is moved onto the second lower mold part holder 13c.

Figure 5 illustrates the first mold part 14b, which is made to perform a translational motion by the pushing force transmitted to the first mold part 14a by the linear actuator 28 by means of the fork 32 and the protrusion 33, and is arranged on the second lower mold part holder 13c.

From there, the second actuator 18b lifts it so as to close against the third mold part 14c, so as to form the second impression for overmolding a second portion of said two-color product to be obtained.

The EVA of a second color is injected so as to form, on the first portion of a first color, said second portion of a second color, in order to complete the product made of EVA.

Figure 6 illustrates schematically the injection of EVA of a second color from the second injector 15b.

The first mold part 14a and the third mold part 14c are heated to the cross-linking temperature of the EVA.

At the end of the cross-linking process, the mold is opened by lowering the third mold part holder 13c and the product is extracted. In practice it has been found that the invention thus described solves the intended aim and objects.

In particular, the present invention provides a vertical injection machine for the injection molding of soles, technical articles and the like, which allows operators, by means of the in-line arrangement of the presses 12 and of the molding stations 27, to avoid hindering each other in accessing the machine, at the same time facilitating access from both parts for cleaning and maintenance operations, which are particularly important in the field of EVA molding.

The convenience of access to the machine 10 from both sides is further very useful also in the molding and production steps, for operations such as the removal of the finished product, for positioning any inserts in the molds, for siliconizing and for other similar operations.

Further, the present invention provides a modular machine which, being constituted by the modular frameworks 20, can be equipped with such a number of presses 12 or molding stations 27 as to meet in an optimum manner the production requirements.

Moreover, the present invention provides a vertical injection molding machine which can be set up to obtain multicolored products; in particular, the molding stations 27 and the vertical injection assembly 15 with two injectors allow quick and precise molding of products made of two-color

EVA.

Further, in the molding stations 27 only the first lower mold part 14a moves, without the provision of a mold supporting carriage which performs a translational motion as in known types of machine; in this manner, only the mold part 14a needs to be cooled from the EVA cross-linking temperature and its mold holder carriage does not, consequently reducing the thermal inertia of the mold, with important savings in terms of energy expended for cooling and for restoring the conditions required to proceed with a new injection in the first mold part 14a. Moreover, the present invention provides a vertical injection machine for molding soles, technical articles and the like which can be manufactured cheaply with known systems and technologies.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.

In practice, the materials employed, so long as they are compatible with the specific use, as well as the dimensions, may be any according to requirements and to the state of the art. The disclosures in Italian Patent Application No. PD2005A000374 from which this application claims priority are incorporated herein by reference.