ITUB20154739A1 - EXTRUSION CONTACT HEAD - Google Patents

Description

CONTACT EXTRUSION HEAD

TECHNICAL FIELD

The present invention relates to the field of contact extrusion heads, in particular for the contact extrusion of strips of glue on flexible supports.

STATE OF THE ART

In the field of extrusion there are known machines equipped with extrusion heads intended to extrude strips of glue spaced apart on flexible supports (eg paper tape, aluminum, sheets or plastic strips, fabric, etc.).

In short, as the person skilled in the art knows, the extrusion of strips of material, for example glue, on a flexible support is subject to general problems concerning mainly the control of the dimensions of the strips and their precise positioning on the support, which affect the repeatability of the process. In particular, a particularly used device is the one described in the European patent EP1497042, which shows a contact extrusion head provided with a head block in which a passage for the material being extruded is identified, an extrusion lip of the head which develops in a first direction, provided with a plurality of orifices arranged along the lip close to each other and in communication with the passage of the material and a cylinder arranged substantially parallel with respect to the first direction. Contact extrusion differs substantially from simple glue spreading.

In EP1497042 the strips are generated by the orifices, which determine their position and size on the flexible support.

Although generally satisfactory, however, the known art has some limitations.

In particular, the orifices for the extrusion of the strips are made by the extrusion lip which, suitably shaped, interrupts the flow of the glue in the areas of the flexible support which must be left uncovered by the same.

If the shapes or sizes of the strips have to be changed, the entire lip must be replaced, with relatively high intervention times and costs.

Furthermore, any localized wear of the lip inevitably involves its complete replacement or, if nothing else, its removal for subsequent rectification or repair.

PURPOSES AND SUMMARY OF THE INVENTION

It is an object of the present invention to overcome the drawbacks of the known art.

In particular, the object of the present invention is to provide an extrusion head according to the preamble of the first claim, which allows the shape and / or size and / or arrangement of the glue strips dispensed by the head on the flexible holder.

It is also an object of the present invention to provide such a head which is less subject to wear and can be easily restored when worn, possibly being able to act only in coincidence with the worn areas.

These and further objects of the present invention are achieved by means of a head according to the present invention, which incorporates the characteristics of the attached claims, which form an integral part of the present description.

The general idea underlying the present invention provides for the realization of an extrusion head according to the preamble of the first attached claim and which characteristically comprises a plurality of seats and a plurality of inserts housed, at least in part, in a removable way in said seats, which inserts extend at least partly in said channel and at least partly coinciding with said extrusion mouth, so as to generate an extrusion of strips of material on said flexible support.

This solution offers the advantage of being able to modify the shape and / or size and / or arrangement of the strips of material dispensed by the head in a relatively simple way, i.e. by intervening on the individual inserts to replace them with others having an appropriate shape / size and thus avoiding replacing the entire lip, as was the practice in the known solutions.

According to an advantageous aspect, even independent from the other aspects, each of said seats has at least one open mouth turned towards the extrusion mouth and said inserts each have at least one tang portion intended to be inserted into the respective seat through said mouth, so as to allow the assembly of said inserts through the extrusion mouth reducing the time (and consequently the costs) of intervention in their replacement.

According to another advantageous aspect, even independent of the other aspects, the mouths of the seats can be closed again by means of said lip, which further facilitates the maintenance steps.

According to an advantageous aspect, even independent from the other aspects, the block comprises a support element which partially delimits the channel near the mouth and supports the lip, the seats being formed in said support element; thanks to this aspect it is possible, in case of need, to replace the whole support element with another one having seats in a different position.

According to yet another advantageous aspect, also independent from the other aspects, the lip is removable from said body and preferably is removably coupled to the support element (if present), so as to free the mouths of the seats in the condition of the lip removed from the support element; it is thus possible to use the lip of the retaining element in the position of the tangs of the inserts which become removable once the lip itself has been removed, further reducing the time required for this operation. Consequently, a first object of the invention is an extrusion head according to the first attached claim.

Further advantageous characteristics are the subject of the attached claims, which are intended as an integral part of the present description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described below with reference to non-limiting examples, provided for explanatory and non-limiting purposes in the annexed drawings. These drawings illustrate different aspects and embodiments of the invention and, where appropriate, reference numerals illustrating similar structures, components, materials and / or elements in different figures are indicated by similar reference numerals.

In the attached figures:

Figure 1 illustrates a perspective view of the head of the invention in an operating condition;

Figure 2 illustrates an exploded view of the head of the previous figure;

Figure 3 illustrates a sectional view of the head of the preceding figures;

Figure 4 illustrates an enlarged detail of the previous figure;

Figure 5 illustrates an exploded view of part of the head of the previous figures, in particular of the extrusion lip according to the invention;

Figure 6 illustrates a perspective view of the extrusion lip of the previous figure with one insert mounted and one removed;

Figure 7A-7D illustrate front views of the extrusion lip of the previous figures with mounted inserts of different types for making different types of strips on the flexible support.

DETAILED DESCRIPTION OF THE INVENTION

While the invention is susceptible of various modifications and alternative constructions, some preferred embodiments are shown in the drawings and will be described below in detail.

It is to be understood, however, that there is no intention of limiting the invention to the specific embodiment illustrated, but, on the contrary, it is intended to cover all modifications, alternative constructions, and equivalent ones that fall within the scope of the invention as defined in the claims.

The use of "for example", "etc", "or" indicates non-exclusive alternatives without limitation unless otherwise indicated.

Use of "include" means "includes, but not limited to" unless otherwise indicated.

Indications such as "vertical" and "horizontal", "upper" and "lower" (in the absence of other indications) must be read with reference to the assembly (or operating) conditions and referring to the normal terminology used in current language, where "vertical "indicates a direction substantially parallel to that of the gravity force vector" g "and a horizontal direction perpendicular to it.

With reference to figs. 1 and 2, they show an extrusion head 1 in contact with strips S of a material on a flexible support SF (visible in fig. 3 and 4).

The "material" to be extruded in the form of strips S is preferably a glue.

The flexible support SF is for example paper tape, aluminum, plastic sheets or strips, fabric, not shown in fig. 1, and intended to receive the strips S. With reference also to fig. 3 and 4, the head 1 comprises a block 2 in which at least one feed channel 21 for the material for the strips S.

In the solution shown, for this purpose, block 2 comprises two semi-blocks 2 'and 2' 'coupled together. The two semi-blocks 2 'and 2' '(or, more generally, block 2) define at least part of the channel 21 (in particular the one furthest from the mouth 22) into which the material flows (which from now on, does not limitatively, it will be indicated as "glue") starting from a source (not shown).

The channel 2 1 has an innermost portion 21 'that is substantially tubular, which widens into a blade portion 21' 'upstream (following the flow of the glue) of the extrusion mouth 22, so as to allow dispensing of the glue with substantially pressure constant over the entire spout 22 regardless of the distance of the single dispensing point from the tubular section 21 ', according to a principle well known per se in the state of the art and on which no further details are given.

The head 1 then comprises an extrusion lip 4 coupled to the block 2 and placed in correspondence with the extrusion mouth 22.

In particular, the lip 4, in the illustrated embodiment, is coupled to a support element 2 '' 'which ideally forms part of the block 2, which, in the operating condition, is positioned and below the half-block 2', coupled to the half-block 2 '' and blocked against the last guest by the half-block 2 'itself.

The lip 4, in particular, is coupled in an amobivably manner to the support element 2 '' ', for example by means of screws 49, visible in fig. 4, so that it can be mounted or removed.

Said lip 4 partially delimits the extrusion mouth 22 and, in the example shown, delimits in particular its lower part.

As "extrusion mouth" 22 we want to indicate the open area of the channel 2 1, through which the glue exits the head 1 to deposit in strips S on the flexible support SF.

According to the type of "contact" extrusion selected, a rotating cylinder 5 is provided, facing the lip 4 and extending at least for the entire length of the last guest; the function of the rotating cylinder 5 is well known in the technical field and we do not dwell on it further, except to note that typically the cylinder 5 is coupled to the upper half-block 2 '.

In accordance with the teachings provided and with reference also to figs. 5 and 6, the head 1 comprises a plurality of seats 41 and a plurality of inserts 42 housed at least in part and in a removable way in the seats 41.

The inserts 42 extend at least in part in the channel 21 (i.e. inside it) and preferably at least in part coinciding with the extrusion mouth 22, so as to generate an extrusion of strips S of material on the flexible support SF: the glue in fact flows into the channel 2 1 until it meets the inserts 42 which divide it into fluid portions which, once out of the mouth 22, form the strips S.

In this way it is possible, by replacing the individual inserts 42, one by one or all together, to modify the shape and / or dimensions and / or mutual distances of the strips S by acting only on the inserts 42, for example by replacing a certain type of inserts with others more suitable for the purpose, as is more evident from figs. 7A-7D.

Similarly, the maintenance of the head 1 is more economical: it is in fact sufficient to replace the individual worn inserts 42, leaving the non-worn ones in their place.

In order to further improve the operations just described, each of the seats 41 has at least one open mouth 43 facing the extrusion mouth 22, as shown in fig. 6.

Similarly, the inserts 42 each have a substantially mushroom-like shape with at least a portion of the shank (or shank) 44 intended to be inserted in the respective seat 41 to couple the insert 42 to the respective seat 41.

Since the mouth 43 faces the mouth 22, it follows that the replacement of the inserts 42 can be advantageously carried out by acting through the mouth 22 itself, avoiding having to disassemble the whole head 1. In particular, as in the example shown, the seat 41 is dovetail-shaped and equally the shank 42 has a complementary shape, to determine an undercut which prevents the insertion / disengagement of the shank 44 from the seat 41 in any direction other than that which sees the shank 44 pass through the mouth 43.

Thanks to this expedient, each insert 42 can be removed from its respective seat 41 (or inserted into it) only through the mouth 43 of the last guest.

Each insert 42 is therefore retained within its seat 41 thanks to the lip 4: this derives from the fact that the mouths 4 3 can be closed by the lip 4, as can be seen from fig. 5.

To this end, in the illustrated embodiment, the seats 41 are obtained in the support element 2 '' ', which also supports the lip 4 as well as defining the end part of the channel 21, immediately before the mouth 22.

Therefore, if one or more inserts 42 are to be replaced, it is sufficient to disassemble the lip 4 by acting on the screws 49 - thus releasing the mouth 43 of the seats 41 - and extract the inserts 42 through the mouth 22.

As evident from figures 7A-7D, by replacing the inserts 42 different strips S (wider, narrower, closer or further away) can be obtained.

The purposes listed above are thus achieved.

Numerous variations are obviously possible to what has been described up to now.

For example, the support element 2 '' 'could be in one piece with the semi-block 2' 'and physically indistinguishable from the latter, even if present.

Similarly, the support element 2 '' 'could be absent; in this case the seats 41 will be made directly on the half-block 2 '' which also supports the lip 4.

Furthermore, the dovetail shape of the seats 41 and of the tangs 4 3 could be replaced by a similar shape coupling which has an undercut suitable for achieving the same functionality.

The fixing screws can then be replaced in an equivalent way with similar screw connections (bolts and nuts) or with other mechanical couplings.

Claims (6)

CLAIMS 1) Head (1) for contact extrusion of strips (S) of a material on a flexible support, comprising: - a block (2) of the head in which at least one channel (21) for feeding the material is made which ends in coincidence with an extrusion mouth (22), - an extrusion lip (4) coupled to said block (2) of the head placed in correspondence with the extrusion mouth (22) and able to partially delimit the latter, a rotating cylinder (5), facing said lip (4) and extending at least for the entire length of the latter, characterized by the fact that the head (1) comprises a plurality of seats (41) and a plurality of inserts (42) housed, at least in part, in a removable way in said seats (41), which inserts (42) extend at least partially in said channel (21) and preferably at least partially coinciding with said extrusion mouth (22), so as to generate an extrusion of strips (S) of material on said flexible support. 2) Extrusion head (1) according to the preceding claim, in which each of said seats (41) has at least one open mouth (43) facing the extrusion mouth (22) and said inserts (42) each have at least one portion shank (44) intended to be inserted into the respective seat (41) through said opening (43), so as to allow the assembly of said inserts (42) through the extrusion mouth (22). 3) Extrusion head (1) according to claim 1 or 2, in which the mouths (43) of the seats (41) can be closed again by means of said lip (4). 4) Extrusion head (1) according to one or more of the preceding claims, wherein said block (2) comprises a support element (2 '' ') which partially delimits said channel (21) near the mouth (22) and supports said lip (4), said seats (41) being formed in said support element (2 '' '). 5) Extrusion head (1) according to one or more of the preceding claims, in which said lip (4) is removable from said body (2). 6) Extrusion head (1) according to one or more of claims 4 or 5, in which said lip (4) is removably coupled to said support element (2 '' '), so as to free the mouths (43) seats (41) in condition of lip (4) removed from the support element (2 '' ').