IT202300006003A1 - REEL FOR SUPPORTING POLYMERIC THREADS - Google Patents

Description

Description of a Patent for an Industrial Invention entitled:

?COIL FOR SUPPORTING POLYMERIC THREADS?.

DESCRIPTION

The present invention relates to a coil for supporting wires made of polymeric material.

In the industrial sector dealing with the production of polymeric threads, for example for use in three-dimensional printing devices, it is well known that these threads are packaged in special spools onto which they are wound.

The known type of coils comprise a central support that extends along a longitudinal axis and around which the wire can be wound and a pair of associated lateral sides positioned opposite the ends of the central support.

The known type of coils are mounted on special winding machines which, by rotating the coil, cause the wire to wind around the central support.

Once the wire has been wound to the desired length, it is cut to define a free end portion of the wire itself.

Most types of polymeric threads, and in particular those for 3D printing devices, have a level of intrinsic stiffness and/or elasticity that tends to cause the thread to unwind if it is not fixed.

For this reason, in some cases, the extreme portion of the wire is fixed using an adhesive support. The adhesive supports used are generally small in size, low in cost and can be reused by the customer in the event of only partial use of the wire. However, the adhesive material of these supports is not always compatible with the material the wire is made of and can cause the support to detach during transport/storage of the coil.

Alternatively, the wire can be fixed to the reel by wrapping a band, of a width corresponding to the extension of the central support, around the internal circumference of the central support itself. The use of a band allows for greater protection of the wire from external agents and ensures optimal fixing of the same. However, the use of a band does not allow for reuse of the same in the case of only partial use of the wire. In addition, both of the aforementioned solutions determine an increase in the final cost of the wire, determined by the use of additional packaging elements with substantially zero added value, as well as the generation of waste materials.

In order to overcome at least in part the above mentioned drawbacks, coils are known which are provided with one or more through holes made in one of the lateral sides and through which the extreme portion of the coil can be inserted, along the relative direction of development.

However, as mentioned above, polymeric wires, such as those used in 3D printing devices, have a level of stiffness that does not easily allow such a bending of the wire and are difficult to fix on reels of this type.

Finally, it should not be underestimated that, for all known solutions, the fastening operation cannot be carried out automatically, unless additional packaging elements are used, on the winding machine or must be carried out manually by an operator, or must be carried out on separate machines, requiring the bobbin to be moved with the risk of the wire unwinding during transfer.

It is evident, therefore, that the known type of coils are susceptible to improvements.

The main task of the present invention is to devise a coil for supporting polymeric wires which allows to effectively fix the wire wound on it, avoiding the use of additional packaging elements.

Another purpose of the present invention is to devise a coil for supporting wires made of polymeric material which allows for easy fixing even of wires having a high level of rigidity and/or elasticity.

A further aim of the present invention is to devise a reel for supporting polymeric wires which allows for automated fastening which can be performed on the same machine used for winding the wire.

Another purpose of the present invention is to devise a coil for supporting polymeric material wires that allows the aforementioned drawbacks of the known art to be overcome within the scope of a simple, rational, easy and effective solution to be used and at a low cost.

The above-mentioned aims are achieved by the present coil for supporting polymeric material threads having the characteristics of claim 1. Other characteristics and advantages of the present invention will become more evident from the description of a preferred, but not exclusive, embodiment of a coil for supporting polymeric material threads, illustrated for indicative, but not limitative, purposes in the attached drawings in which:

Figure 1 is an axonometric view of a coil according to the invention; Figure 2 is an axonometric view of a coil according to the invention, following the winding and fixing of a wire;

Figure 3 is a detailed axonometric view of the retaining portion according to the invention;

Figure 4 is a detailed front view of the retaining portion according to the invention;

Figure 3 is a detailed top view of the retaining portion according to the invention.

With particular reference to these figures, the number 1 generally indicates a coil for supporting polymeric material wires.

The coil 1 comprises at least one central support 2 which extends along a longitudinal axis L and around which a wire F made at least partly of polymeric material can be wound.

In detail, the central support 2 is substantially cylindrical.

The coil 1 also comprises at least one pair of side walls 3 associated opposite the ends of the central support 2.

The side rails 3 have the function of containing the wire F and preventing its lateral movements.

Each of the lateral sides 3 develops on a relative development plane S substantially perpendicular to the longitudinal axis L.

In detail, the 3 side walls are arranged substantially parallel to each other.

In accordance with the embodiment shown in the figures, the side panels 3 have a substantially circular shape.

Each of the side walls 3 is provided with a perimeter edge 4. Always with reference to the embodiment shown in the figures, the perimeter edge 4 defines a substantially cylindrical surface which develops around the longitudinal axis.

However, it cannot be excluded that the side walls 3 and consequently the relative perimeter edge 4 have a different shape, for example polygonal.

Each of the side walls 3 also includes an internal face 5 facing the internal face 5 of the other side wall 3 and an external face 6 facing outwards.

In use, the wire F is contained between the internal faces 5 of the side walls 3. The coil 1 also comprises at least one locking portion of the wire F, not shown in the figures, suitable for receiving a first extreme portion of the wire F prior to winding. The locking portion comprises a through hole placed between the central support 2 and one of the side walls 3.

Coil 1 is made of a material chosen from the list including: polycarbonate, polysulfone, polypropylene, acrylonitrile butadiene styrene, paperboard material, wood. However, it is not excluded that coil 1 is made of a different material.

According to the invention, at least one of the side walls 3 comprises at least one retaining portion 7 configured to retain an extreme portion P of the wire F wound on the reel 1.

The retaining portion 7 is configured to retain a second extreme portion of the wire F, resulting from cutting the same after winding.

The retaining portion 7 has the function of retaining the thread F by means of friction between the relative surfaces.

The retaining portion 7 comprises at least two recesses 8 defined on the perimeter edge 4 and inside which the extreme portion P can be inserted.

Usefully, each of the recesses 8 develops on the development plane S. Furthermore, the recess 8 develops from the perimeter edge 4 towards the centre of the side wall 3.

Each of the recesses 8 is connected to the outside at the external face 6 and at the internal face 5. In practice, the recess 8 defines a gap in the side wall 3, at the perimeter edge 4.

In this way, the F wire can be inserted into the recess along a direction orthogonal to its own development direction and does not require excessive deformations which could cause it to break.

Usefully, the recesses 8 are arranged in succession along the perimeter edge 4 and the retaining portion 7 comprises a protrusion 9 interposed between the recesses 8 and defining part of the perimeter edge 4.

During fastening, the wire F is passed between the recesses 8, around the protrusion 9. In other words, the wire F is passed from inside the coil 1 to the outside of the same, through a first recess 8 and then again inside the coil 1, wrapping it partly around the protrusion 9 and inserting it into the second recess 8.

By doing so, the outer surface of the wire F contacts the retaining portion 7 extensively and the friction between the relative surfaces generates a friction force that keeps the wire F fixed to it.

It is not excluded that the retaining portion 7 may comprise more than two recesses 8 and corresponding protrusions 9.

Furthermore, it is not excluded that the coil 1 may comprise a plurality of retaining portions 7, arranged at different points of the same lateral edge 3 or on both.

Advantageously, the recesses 8 are arranged symmetrically with respect to a median plane M passing through the longitudinal axis L.

In practice, the recesses 8 have similar and symmetrical shapes. In this way, the wire F can be inserted indiscriminately into one or the other recess 8, regardless of the winding direction.

The recess 8 defines an internal surface substantially contiguous to the perimeter edge 4.

In particular, each of the recesses 8 comprises a base surface 10 that is substantially planar and perpendicular to the median plane M.

The arrangement of the base surface 10 facilitates the sliding of the wire F during fastening.

Furthermore, the base surfaces 10 of the recesses 8 are substantially coplanar. In this way, the extreme portion P undergoes deformations only on the plane defined by the base surfaces 10.

Usefully, the recess 8 also includes a pair of lateral surfaces 11, adjacent to the base surface 10 and inclined with respect to the latter. The lateral surfaces 11 are in turn planar and connect to the base surface 10 at their respective ends in a relative connecting surface 12.

The connecting surface 12 between the lateral surface 11 and the base surface 10 has a curvilinear development which allows to avoid possible crushing and/or deformations of the wire F.

In addition, the edge of the base surface 10, of the lateral surfaces 11 and of the connecting surfaces 12 is chamfered, so as to facilitate the application of the wire F and avoid possible lacerations of the same.

The lateral surfaces 11 extend from the base surface 10 towards the perimeter edge 4.

Advantageously, the lateral surfaces 11 converge towards each other away from the base surface 10.

In practice, the base surface 10 and the lateral surfaces 11 are arranged together to define a sort of prism with a triangular base.

This conformation prevents the wire F from slipping out of the recess 8 and allows it to be kept in correspondence with the base surface 10.

In accordance with a preferred embodiment, the lateral surface 11 is inclined with respect to the base surface 10 by an angle between 10° and 50°. Preferably, the lateral surface 11 is inclined with respect to the base surface 10 by an angle between 10° and 35°. Even more preferably, the lateral surface 11 is inclined with respect to the base surface 10 by an angle between 10° and 20°.

Usefully, the recess 8 also includes a proximal surface 13 interposed between one of the lateral surfaces 11 and the perimeter edge 4.

In the present discussion, the terms ?proximal? and ?distal? refer to the relative position of the surfaces with respect to the median plane M.

The proximal surface 13 is therefore located close to the median plane M and is inclined with respect to it.

Specifically, the proximal surfaces 13 of the recesses 8 converge with each other away from the external face 6.

The recess 8 also includes a distal surface 14 interposed between the other of the lateral surfaces 11 and the perimeter edge 4.

The distal surface 14 is arranged at a distance from the median plane M. The distal surfaces 14 of the recesses 8 diverge from each other away from the respective lateral surfaces 11.

The distal surfaces 14 and the proximal surfaces 13 are respectively designed to facilitate the insertion of the wire F into the recess 8 and its wrapping around the protrusion 9.

Usefully, at least one of the base surface 10, the lateral surface 11, the connecting surface 12, the proximal surface 13 and the distal surface 14 may have a rough surface finish designed to increase the frictional force generated on the extremal portion P.

Preferably, the distal surface 14 and the proximal surface 13 have a smooth finish to facilitate the insertion of the wire F into the recesses 8.

Advantageously, the retaining portion 7 comprises a guide rib 15 protruding from the external face 6, extending along the entire length of the retaining portion 7 and capable of guiding the movement of the wire F.

The guide kerb 15 extends from the perimeter edge 4 and then rejoins it.

The recesses 8 are defined between the perimeter edge 4 and the guide kerb 15.

Usefully, the protrusion 9 also includes an external kerb, defining the relative perimeter edge 4 and protruding with respect to the external face 6.

In use, part of the extreme portion P is placed between the two kerbs, which prevent accidental transverse movements of the extreme portion itself.

The operation of the present coil in the execution of the method according to the invention for the winding of wire in polymeric material is as follows. The method comprises first of all a step of supplying a coil 1 according to one or more of the embodiments described above and a step of supplying a wire F made at least in part of polymeric material and a winding machine suitable for winding the wire F on the coil 1.

In particular, the thread may be made of at least one polymeric material selected from the list including: polylactic acid, acrylonitrile butadiene styrene, polyethylene terephthalate, glycol-modified polyethylene terephthalate, polycarbonate, polyamide, thermoplastic polyethylene, thermoplastic polyurethane, plastic wood, high impact polystyrene, polyvinyl alcohol, polyethylene cotrimethylene terephthalate, metallic polylactic acid, carbon fiber polylactic acid, lignin, conductive polymer, wax, acrylonitrile styrene acrylate, polypropylene, polyoxomethylene, polymethyl methacrylate, luminescent polymer, Polycarbonate/Acrylonitrile butadiene styrene, magnetic polymer, thermoplastic polyester elastomer, flexible polyester, polyetherimide.

In detail, the F-wire has a diameter between 1 mm and 3.5 mm. Preferably, the F-wire has a diameter between 1.75 mm and 2.85 mm.

The method then includes a loading step of the coil 1 onto the winding machine.

At this point, the winding machine rotates the coil 1 in order to determine the position of the retaining portion. This operation is performed by means of distance sensors arranged near the perimeter edge 4 and capable of detecting the distance of the side wall 3 from the sensor itself. In practice, following the rotation, when the recess 8 is positioned in correspondence with the distance sensor, the latter detects a gap and consequently determines the position of the retaining portion 7. The distance sensor is of a type known to those skilled in the art and can be chosen from the list comprising: laser sensor, photoelectric sensor, optical sensor.

Subsequently, the method comprises a phase of interlocking fixing of a first extreme portion of the wire F in the coil 1. This phase is carried out by inserting the wire F inside the locking portion. The method then comprises a phase of rotating movement of the coil 1 carried out in such a way as to determine the winding of the wire F around the coil.

In detail, the winding machine, of a type known to those skilled in the field, comprises a dispensing device capable of dispensing the wire F and which can be moved in translation parallel to the longitudinal axis L during winding.

Once the desired length has been reached and prior to the cutting phase, the method comprises a phase of fixing the wire F to the retaining portion 7 performed by means of the winding machine. In detail, the dispensing device is responsible for moving the wire F between the recesses 8 at the end of the winding.

More specifically, the fixing phase involves a first step of inserting the wire F into a first recess 8, carried out towards the outside of the coil 1, i.e. from the internal face 5 to the external face 6, and a second step of inserting the wire F into the second recess 8, carried out towards the inside of the coil 1, i.e. from the external face 6 to the internal face 5, around the protrusion 9.

Subsequently, the method involves a cutting phase of the wire F to define the second extreme portion P. The extreme portion P is thus already fixed to the coil 1.

However, it is not excluded that the fixing phase is carried out after cutting, using a specific fixing device mounted on the same winding machine.

Finally, the method includes a phase of unloading the coil 1 from the winding machine performed after the fixing phase. In practice, once the coil 1 is removed from the winding machine, the wire F is already fixed to it and does not require further intervention by an operator or transfer to other fixing machines, significantly reducing operating times, related costs and avoiding accidental unwinding of the wire F during these operations.

In practice, it has been observed that the described invention achieves the proposed purposes and in particular it is highlighted that the coil according to the invention for supporting wires made of polymeric material allows the wire wound on it to be effectively fixed, avoiding the use of additional packaging elements.

Furthermore, this coil allows for easy attachment of wires with a high level of stiffness or elasticity.

Furthermore, this reel allows for easy fixing of wires even after a portion of wire has been used by an end user, making it easy to store partially used reels.

Finally, this coil allows for automated fastening that can be performed on the same machine used for winding the wire.

Claims (12)

1) Reel (1) for supporting polymeric material threads comprising at least one central support (2) which extends along a longitudinal axis (L) and around which a thread (F) made at least partly of polymeric material can be wound and at least one pair of lateral sides (3) associated opposite the ends of said central support (2) and each provided with a perimeter edge (4), characterised in that at least one of said lateral sides (3) comprises at least one retaining portion (7) configured to retain an extreme portion (P) of said thread (F) wound on said reel (1), in which said retaining portion (7) comprises at least two recesses (8) defined on said perimeter edge (4) and inside which said extreme portion (P) can be inserted. 2) Coil (1) according to claim 1, characterised by the fact that each of said lateral sides (3) develops on a relative development plane (S) substantially perpendicular to said longitudinal axis (L) and by the fact that each of said recesses (8) develops on said development plane (S). 3) Coil (1) according to one or more of the preceding claims, characterised in that each of said lateral sides (3) comprises an internal face (5) facing the internal face (5) of the other lateral side (3) and an external face (6) facing outwards and in that each of said recesses (8) is communicating with the outside in correspondence with said external face (6) and in correspondence with said internal face (5). 4) Coil (1) according to one or more of the preceding claims, characterised in that said recesses (8) are arranged in succession along said perimeter edge (4) and in that said retaining portion (7) comprises a protrusion (9) interposed between said recesses (8) and defining part of said perimeter edge (4). 5) Coil (1) according to one or more of the preceding claims, characterised in that said recesses (8) are arranged symmetrically with respect to a median plane (M) passing through said longitudinal axis (L) 6) Coil (1) according to one or more of the preceding claims, characterised in that each of said recesses (8) comprises a base surface (10) substantially planar and perpendicular to said median plane (M) and in that the base surfaces (10) of said recesses (8) are substantially coplanar. 7) Coil (1) according to one or more of the preceding claims, characterised in that said recess (8) comprises a pair of lateral surfaces (11), contiguous to said base surface (10) and inclined with respect to the latter and in that said lateral surfaces (11) converge with respect to each other away from said base surface (10). 8) Coil (1) according to one or more of the preceding claims, characterised in that said recess (8) comprises a proximal surface (13) interposed between one of said lateral surfaces (11) and said peripheral edge (4), arranged in proximity to said median plane (M) and inclined with respect to it and in that the proximal surfaces (13) of said recesses (8) converge with respect to each other away from said external face (6). 9) Coil (1) according to one or more of the preceding claims, characterised in that said recess (8) comprises a distal surface (14) interposed between one of said lateral surfaces (11) and said peripheral edge (4), arranged at a distance from said median plane (M) and in that the distal surfaces (14) of said recesses (8) diverge from each other away from the respective lateral surfaces (11). 10) Coil (1) according to one or more of the preceding claims, characterised in that said retaining portion (7) comprises a guide rib (15) protruding from said external face (6), extending along the entire length of said retaining portion (7) and capable of guiding the movement of said wire (F). 11) Coil (1) according to one or more of the preceding claims, characterised in that said recesses (8) are defined between said perimeter edge (4) and said guide kerb (15). 12) Method for winding a thread in polymeric material characterised by comprising the following phases: - supply of a coil (1) according to one or more of the preceding claims; - supply of a wire (F) made at least partly of polymeric material and of a winding machine suitable for winding said wire (F) onto said reel (1); - loading said coil (1) onto said winding machine; - interlocking fixing of a first extreme portion (P) of said wire (F) into said coil (1); - rotational movement of said coil (1) performed in such a way as to determine the winding of said wire (F) around said coil (1); - fixing of said wire (F) to said retaining portion (7) performed by means of said winding machine; - cutting of said wire (F) to define a second extreme portion (P); - unloading of said coil (1) from said winding machine performed after said fixing phase.