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The present invention relates to the field of machines for making stoppers formed by cork agglomerate, and more particularly has as its object a dosing device and mold assembly of machines for making cork agglomerate stoppers.
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As is known, cork stoppers are manufactured in different ways, depending on the quality of the raw material available. High quality productions provide for making stoppers in a single piece from a compact matrix of cork coming directly from the bark of the tree, while lower quality products provide for the use of agglomerate of cork granules coming from the processing waste of high quality stoppers or from batches that are not qualitatively suitable for single-piece stoppers; these granules are bound by a matrix of non-toxic glue.
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There are different techniques to make agglomerate stoppers. One of these involves the introduction of doses of granule agglomerate mixed with glue into molds comprising molding hoses. The agglomerate with glue is then pressed and subsequently transferred to the oven for the time necessary for solidification. After appropriate cooling, the stopper is extracted from the molding hose by pushing a rod-like extraction body. The correct dose of granules to be introduced into the corresponding mold is prepared by means of a dosing device.
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The molds for making cork agglomerate stoppers consist of a frame formed by two elongated plates and a series of molding hoses that are aligned and overlapping between these plates. On the latter there are holes, one for each hose. The hoses are fixed to a common translation actuator that allows them to be moved along the same line from a configuration in which the hoses are arranged in a manner matching with the holes to allow the loading of the doses of cork granules, to a translated configuration in which the hoses are closed by the inner faces of the plates, to allow the molding step.
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A known type of dosing device provides a base frame that supports a box-like body which develops longitudinally according to a horizontal orientation. At the bottom of this box-like body there is a drawer, also with a predominant longitudinal development, on which a plurality of dosing cells open upwards are defined. These cells are distributed according to arrays aligned along the longitudinal direction and are adapted to contain the cork granules mixed with glue coming by falling from a loading hopper placed above the box-like body.
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Without going further into the merits, since the structure and functionality of the drawer device are known to those skilled in the art and are not the subject-matter of the invention, nor are they directly related to it, it is sufficient to note that the drawer is provided with a translation movement in a transverse direction (i.e. orthogonal to its direction of elongation), between a loading position, in which the cells receive the granules, and an unloading position in which the drawer is arranged at the mold, above it, matching the cells with the hoses (for this purpose the distributions are congruent to each other), to provide for the transfer and loading of the granules inside the hoses of the mold.
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In this known solution, there are several drawbacks encountered.
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A first order of problems concerns the dispersion of the granule material in the transfer step from the drawer to the mold. In fact, the current mechanical interface relationship between the two components is such that a certain amount of material instead of being deposited within the bushes remains dispersed on the upper face of the mold. In fact, the mold comes into abutment with its upper face (the upper face of the top plate) on the movable shutter of the drawer, so that when it moves, escape and deposit gaps of the cork granulate are created. This dispersion, which is itself a source of waste and economic loss, can also lead to malfunctions, resulting in machine downtime, production losses and maintenance costs.
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A second order of problems has to do with the translation of the drawer. Current systems, with recirculating ball screws or with linear hydraulic actuators, do not always ensure correct alignment, are subject to wear and problems of adjustment and calibration and movement control in general, requiring the use of sensors (and therefore construction complications) to try to at least partially overcome the aforesaid drawbacks.
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The object of the present invention is therefore to solve the problems just highlighted, by providing a drawer dosing assembly and relative mold for a machine for molding cork agglomerate stoppers which on the one hand minimizes material losses in the transfer between drawer and mold, making this step more reliable and safe, and on the other hand makes the movement of the drawer more precise and with a control that is held as accurate as possible and not subject to decay over time.
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This object and other significant ancillary objects are achieved by the drawer dosing device and relative mold for a machine for molding cork agglomerate stoppers according to the present invention, the essential characteristics of which are defined by the first of the appended claims.
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The characteristics and advantages of the dosing device and mold assembly according to the present invention will become clearer from the following description of one of its embodiments, made by way of non-limiting example, with reference to the attached drawings in which:
- figure 1 is a perspective view of the drawer dosing device according to the present disclosure;
- figure 2 is a top plan view of the drawer device of figure 1, limited to the area of the drive mechanism;
- figures 3a and 3b are side views of the area of the drive mechanism of figure 2, respectively in the closed and open position;
- figure 4 is a sectional view of the drawer and mold assembly according to a longitudinal sectional plane, i.e. along the axis of elongation of these elements and on a plane orthogonal to the movement axis of the drawer;
- figure 5 and figure 6 are two progressively larger enlargements of the assembly as seen in figure 4.
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With reference to said figures, a dosing device comprises a drawer 1 having an elongated shape according to an axis X. The drawer traditionally provides a plurality of cell arrays 11 in which the granule material for molding cork stoppers is loaded and dosed.
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For functional loading requirements, the drawer, as is known, must be moved from a closed, forwards displaced position and an open, rearwards displaced position, this movement occurring according to a transverse axis Y orthogonal to the axis of elongation of the drawer.
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With regard to this movement, which represents a first aspect of the present disclosure, with reference in particular to figures 1, 2, 3a and 3b, a drive mechanism 2 is provided which exploits the principle of crank slider mechanism. In the mechanism 2, in fact, a drive shaft 21, parallel to the axis X, can be distinguished, on which one or more cranks 22 is keyed, in the example two cranks duly spaced apart and advantageously made integral with each other also at the free end by a stiffening shaft 23, respective connecting rods 24 being, in turn pivoted via a bracket 25 to the drawer 1, all with axes of articulation parallel to the axis X. The drive shaft 21 is driven by a geared motor system, preferably brushless, partially visible in figure 1 and indicated with 26.
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Figures 3a and 3b show how the rotation of the shaft 21, and consequently of the cranks 22 driven by it, by means of the connecting rods 24 induces the drawer 1, which is guided for linear (horizontal) sliding along the axis Y, to move between a forwards displaced (closed) position as in figure 3a, and a rearwards displaced (open) position as in figure 3b.
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The precision and reliability over time that this movement system ensures, due to the actuation by a single rotating shaft controlled by a suitably sized and adjusted motorization, are very high, and the resulting linear displacement for the drawer can be controlled with maximum resolution. The small number of components and the structural simplicity of the mechanism are precisely such that they do not compromise the precision as the life of the machine progresses.
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According to another aspect of the disclosure, which can also be independent of the first and lend itself to being used also independently of it (the thing being valid also in reverse, i.e. the former being used independently of the latter), with specific reference to figures 4 to 6, the relationship between the drawer 1 and the relative mold arranged below the drawer presents a particular and unprecedented interface configuration. The mold is indicated with 3 and having the known structure with bushes 31 and plates 32, not described in detail as they have completely known characteristics, except as specified below.
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The aforesaid interface configuration between drawer 1 and mold 3, overall, has a distribution of cylindrical tubular hoses 12, each in correspondence to a respective molding bush 31 and having an end 12a fitting with the corresponding hole 32a of the top plate 32, which hole in turn corresponds to the hollow of the bush 31. The hoses 12 protrude downwardly from a fixed base 13 of the drawer, within which a movable shutter 14 slides (according to the axis X); wherein the real body of the drawer, that is, its movable part which has already been mentioned, therefore abuts on an upper face 13a of the fixed base (figure 6). Together with the hoses 12, a distribution of spacers 15 (in turn preferably cylindrical in shape) protrudes downwardly from the fixed base 13, which are adapted to abut on the top plate 32, in the space between the hoses 12. Ultimately, a spaced arrangement is obtained between the top plate 32 of the mold and the drawer 1, more precisely its fixed base, and the movable shutter 14 is no longer, as in the prior art, in contact with the top plate of the mold.
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As a result of this configuration, and in particular of the conveying action carried out by the hoses 12 which by matching with the holes of the mold lead the flow of the material, the dispersion of the granule material is significantly reduced compared to the traditional configuration.
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Further improvement is provided by the precision of the movements of the parts, which being controlled by a brushless motor with high precision, ensure a closure in exact concomitance with the ascent of the rod-like body that transfers the granulate from drawer to mold, so as to close the entry hole of the bushes of the mold avoiding the escape of granule material.
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The present invention has been described with reference to a preferred embodiment thereof. It is intended that other embodiments may exist which relate to the same inventive core, all falling within the scope of protection of the claims indicated below.