EP4688630A1

EP4688630A1 - Spool for the support of wires made of polymeric material

Info

Publication number: EP4688630A1
Application number: EP24720883.8A
Authority: EP
Inventors: Francesco Vittorio RIVA; Claudio Colombo
Original assignee: Alpaplastic Srl; Fast Assembler Srl
Current assignee: Alpaplastic Srl; Fast Assembler Srl
Priority date: 2023-03-29
Filing date: 2024-03-29
Publication date: 2026-02-11
Also published as: CN121039038A; WO2024201400A1; IT202300006003A1

Abstract

The spool (1) for the support of wires made of polymeric material comprises at least one central support (2) developing along a longitudinal axis (L) and around which a wire (F) made at least partly of polymeric material is windable and at least one pair of side sidewalls (3) associated opposite the ends of the central support (2) and each provided with a perimeter edge (4), where at least one of the sidewalls (3) comprises at least one retaining portion (7) configured to retain an end portion (P) of the wire (F) wound around the spool (1), wherein the retaining portion (7) comprises at least two recesses (8) defined on the perimeter edge (4) and within which the end portion (P) is insertable.

Description

SPOOL FOR THE SUPPORT OF WIRES MADE OF POLYMERIC MATERIAL

Technical Field

The present invention relates to a spool for the support of wires made of polymeric material.

Background Art

In the industry concerned with the production of wires made of polymeric materials, e.g. for use in three-dimensional printing devices, the packaging of such wires into special spools on which they are wound is well known.

Spools of known type comprise a central support that develops along a longitudinal axis and around which the wire is windable as well as a pair of associated sidewalls opposite the ends of the central support.

Spools of known type are mounted on special winding machines, which, by setting the spool in rotation, determine the winding of the wire 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 wires made of polymeric material, and especially wires for three- dimensional printing devices, have an inherent level of stiffness and/or elasticity that tends to result, therefore, in unwinding of the wire itself if it is not secured. For this reason, in some cases, the end portion of the wire is fixed by means of an adhesive backing. The adhesive backings generally used have a small size, a low cost and can be reused by the customer if only part of the wire is used. However, the adhesive material of such backings is not always compatible with the material of which the wire is made and may result in the backing becoming detached during transport/storage of the spool.

Alternatively, the wire can be secured to the spool by wrapping a band having a width corresponding to the extension of the central support, around the entire circumference of the central support itself. The use of a band provides greater protection for the wire from external agents and ensures optimal wire fixation. However, the use of a band does not allow reuse of the same in case of only partial use of the wire. In addition to this, both of the aforementioned solutions result in an increase in the final cost of the wire, brought about by the use of additional packaging elements with substantially no added value, as well as the generation of waste materials.

In order to overcome at least some of the aforementioned drawbacks, spools are known to be provided with one or more through holes cut in one of the sidewalls and through which the end portion of the same can be inserted, along the relevant direction of development.

However, as stated above, wires made of polymeric material, such as those for three-dimensional printing devices, have a level of stiffness that does not easily allow for such wire bending and are not easy to fasten onto reels of this type.

Finally, it should not be underestimated that, for all known solutions, the fastening operation cannot be done automatically, except by using additional packaging elements, on the winding machine or must be unwound manually by an operator, or must be unwound on separate machines, requiring the spool to be displaced with the risk of unwinding the wire during transfer.

It is evident, therefore, how the spools of known type are susceptible to refinements.

Description of the Invention

The main aim of the present invention is to devise a spool for the support of wires made of polymeric material which allows the wire wound thereon to be effectively fastened while avoiding the use of additional packaging elements. Another object of the present invention is to devise a spool for the support of wires made of polymeric material which allows easy fastening even of wires having a high level of stiffness and/or elasticity.

A further object of the present invention is to devise a spool for the support of wires made of polymeric material which allows automated fastening executable on the same machine intended for winding the wire.

Another object of the present invention is to devise a spool for the support of wires made of polymeric material which allows the aforementioned drawbacks of the prior art to be overcome within the framework of a simple, rational, easy and effective to use as well as inexpensive solution. The aforementioned objects are achieved by this spool for the support of wires made of polymeric material having the characteristics of claim 1.

Other characteristics and advantages of the present invention will become more apparent from the description of a preferred, but not exclusive, embodiment of a spool for the support of wires made of polymeric material, illustrated by way of an indicative, yet non-limiting example in the attached tables of drawings in which:

Figure 1 is an axonometric view of a spool according to the invention, in accordance with a first embodiment;

Figure 2 is an axonometric view of the spool in Figure 1, following the winding and fastening of a wire;

Figure 3 is an axonometric detailed view of the retaining portion of the spool in Figure 1;

Figure 4 is a front detailed view of the retaining portion of the spool in Figure 1; Figure 5 is a top detailed view of the retaining portion of the spool in Figure 1; Figure 6 is a front detailed view of the retaining portion of the spool according to the invention, in accordance with a second embodiment;

Figure 7 is a top detailed view of the retaining portion of the spool in Figure 6. Embodiments of the Invention

With particular reference to these figures, reference numeral 1 globally denotes a spool for the support of wires made of polymeric material.

The spool 1 comprises at least one central support 2 developing along a longitudinal axis L and around which a wire F, made at least partly of polymeric material, is windable.

In detail, the central support 2 is substantially cylindrical.

The spool 1 also comprises at least one pair of sidewalls 3 associated opposite the ends of the central support 2.

The sidewalls 3 have the function of containing the wire F and prevent them from moving laterally.

Each of the sidewalls 3 develops on a relevant plane of development S which is substantially perpendicular to the longitudinal axis L. In detail, the sidewalls 3 are arranged substantially parallel to each other.

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

Each of the sidewalls 3 is provided with a perimeter edge 4. Still with reference to the embodiment shown in the figures, the perimeter edge 4 defines a substantially cylindrical surface developing around the longitudinal axis.

It cannot, however, be ruled out that the sidewalls 3 and, consequently, its perimeter edge 4 may have a different conformation, e.g. polygonal.

Each of the sidewalls 3 also comprises an inner face 5 facing the inner face 5 of the other sidewall 3 and an outer face 6 facing outwards.

In use, the wire F is contained between the inner faces 5 of the sidewalls 3.

The spool 1 also comprises at least one blocking portion of the wire F, not shown in the figures, adapted to receive a first ending portion of the wire F prior to winding. The blocking portion comprises a through hole located between the central support 2 and one of the sidewalls 3.

The spool 1 is made of a material selected from the list comprising: polycarbonate, polysulfone, polypropylene, acrylonitrile butadiene styrene, papermaking material and wood. It cannot however be ruled out that the spool 1 may be made of a different material.

According to the invention, at least one of the sidewalls 3 comprises at least one retaining portion 7 configured to retain an end portion P of the wire F wound around the spool 1.

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

The retaining portion 7 has the function of retaining the wire F by friction between the relevant surfaces.

The retaining portion 7 comprises at least two recesses 8 defined on the perimeter edge 4 and within which the end portion P is insertable.

Conveniently, each of the recesses 8 develops on the plane of development S. In addition, the recess 8 develops from the perimeter edge 4 towards the center of the sidewall 3.

Each of the recesses 8 communicates outwards where the outer face 6 and the inner face 5 are located. In actual facts, the recess 8 defines a gap in the sidewall 3 where the perimeter edge 4 is located.

In this way, the wire F is insertable into the recess along a direction orthogonal to its direction of development and does not require excessive deformation that could cause it to break.

Conveniently, the recesses 8 are arranged in succession with each other along the perimeter edge 4 and the retaining portion 7 comprises a protrusion 9 located between the recesses 8 and defining part of the perimeter edge 4.

During fastening, the wire F is made to pass between the recesses 8, around the protrusion 9. In other words, the wire F is made to pass from the inside of the spool 1 to the outside of the same, through a first recess 8 and then back to the inside of the spool 1, winding it partly around the protrusion 9 and inserting it into the second recess 8.

In doing so, the outer surface of the wire F contacts the retaining portion 7 extensively and the friction between the relevant surfaces generates a frictional force that keeps the wire F fastened thereto.

It cannot be ruled out that the retaining portion 7 may comprise more than two recesses 8 and the corresponding protrusions 9.

Likewise, it cannot be ruled that the spool 1 may comprise a plurality of retaining portions 7 arranged at different points on the same sidewall 3 or on both.

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

In actual facts, the recesses 8 have similar and symmetrical conformations.

In this way, the wire F can be inserted indiscriminately into either recess 8, regardless of the way of winding.

In accordance with a first embodiment shown in Figures 1 to 5, the spacing A between the two recesses 8 is of between 15mm and 150mm, preferably it is of between 20mm and 40mm.

The recess 8 defines an inner surface substantially contiguous with the perimeter edge 4.

Specifically, 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 promotes the sliding of the wire F during fastening.

In addition, the base surfaces 10 of the recesses 8 are substantially coplanar. Thus, the end portion P undergoes deformation only on the plane defined by the base surfaces 10.

Conveniently, the recess 8 also comprises a pair of lateral surfaces I la, 11b, contiguous to the base surface 10 and inclined with respect to the latter.

The lateral surfaces 1 la, 1 lb are themselves at least partly planar and join to the base surface 10 where the relevant ends are located.

For this purpose, each of the lateral surfaces 1 la, 1 lb comprises a joining portion 12 which is adjacent to the base surface 10.

The joining portion 12 has a curvilinear development which allows avoiding possible crushing and/or deformation of the wire F.

In addition to this, the edge of the base surface 10, of the lateral surfaces 1 la, 1 lb and of the joining surfaces 12 is beveled, so as to facilitate the application of the wire F and to avoid possible tearing of the same.

The lateral surfaces I la, 11b develop from the base surface 10 towards the perimeter edge 4.

In detail, the pair of lateral surfaces I la, 11b comprises a first lateral surface I la defined on the protrusion 9 and a second lateral surface 1 lb opposite the first lateral surface I la.

Advantageously, the lateral surfaces I la, 11b are convergent with each other away from the base surface 10.

In accordance with the first embodiment, the first lateral surface I la and the second lateral surface 1 lb are symmetrical to each other with respect to a plane of symmetry of the recess 8.

In actual facts, the first lateral surface I la and the second lateral surface 1 lb are inclined with respect to the base surface by the same angle.

The base surface 10 and the lateral surfaces I la, 11b are arranged together to define a kind of prism with a triangular base.

This conformation allows preventing the wire F from slipping out of the recess 8 and allows it to be kept where the base surface 10 is located. In accordance with the first embodiment, the lateral surface I la, 11b is inclined with respect to the base surface 10 by an angle of between 10° and 50°. Preferably, the lateral surface 1 la, 1 lb is inclined with respect to the base surface 10 by an angle of between 10° and 35°. Even more preferably, the lateral surface l la, 11b is inclined with respect to the base surface 10 by an angle of between 10° and 20°.

Conveniently, the recess 8 also comprises a proximal surface 13 contiguous with the first lateral surface I la.

In the context of this disclosure, the terms “proximal” and “distal” refer to the relevant position of the surfaces with respect to the median plane M.

The proximal surface 13 is, therefore, arranged in the proximity of the median plane M and is inclined with respect thereto.

Specifically, the proximal surfaces 13 of the recesses 8 are convergent with each other away from the outer face 6.

The proximal surfaces 13 are inclined with respect to the plane of development S by an angle 0 of between 10° and 60°, preferably of between 20° and 40°.

The recess 8 also comprises a distal surface 14 located between the second lateral surface 1 lb and the perimeter edge 4.

The distal surface 14 is arranged spaced apart with respect to the median plane M and is opposite the proximal surface 13.

In accordance with the first embodiment, the distal surfaces 14 of the recesses 8 are divergent from each other away from their respective second lateral surfaces l lb.

Each distal surface 14 is inclined with respect to the respective base surface 10 by an angle a of between 5° and 45°, preferably of between 10° and 25°.

The distal surfaces 14 and the proximal surfaces 13 are adapted to promote the insertion of the wire F into the recess 8 and the relevant winding around the protrusion 9, respectively.

Conveniently, at least one of the base surface 10, the lateral surface 1 la,l lb, the joining surface 12, the proximal surface 13 and the distal surface 14 may have a rough surface finish adapted to increase the frictional force generated on the end portion P. Preferably, the distal surface 14 and proximal surface 13 have a smooth finish so as to promote the insertion of the wire F into the recesses 8.

Advantageously, the retaining portion 7 comprises a guiding bead 15 projecting from the outer face 6, developing over the full extension of the retaining portion 7 and adapted to guide the movement of the wire F.

The guiding bead 15 develops from the perimeter edge 4 and then rejoins it.

The recesses 8 are defined between the perimeter edge 4 and the guiding bead 15. Conveniently, the protrusion 9 also comprises an outer bead, defining the relevant perimeter edge 4 and protruding with respect to the outer face 6.

In use, part of the end portion P is positioned between the two beads, which allow preventing accidental transverse movement of the end portion itself.

Figures 6 and 7 show a second embodiment of this spool 1 that differs from the previous one in that the first lateral surface I la and the second lateral surface 1 lb are arranged differently from each other with respect to the base surface 10.

The first lateral surface I la and the second lateral surface 11b develop between the base surface 10 and the perimeter edge 4.

The first lateral surface I la has a substantially planar development, net of the respective joining portion 12, and develops along a plane passing through the longitudinal axis L. In other words, the first lateral surface I la develops along a plane passing through the radius of the sidewall 3.

The second lateral surface 1 lb also has a substantially planar development, net of the respective joining portion 12, and develops along a plane substantially parallel to the first lateral surface I la.

In actual facts, where the perimeter edge 4 is located, the first lateral surface I la and the second lateral surface 1 lb are arranged at a distance DI of between 4mm and 10mm, preferably of between 4mm and 7mm.

In accordance with the second embodiment, the proximal surfaces 13 are inclined with respect to the plane of development S by an angle 0 of between 5° and 60°, preferably of between 10° and 40°, even more preferably of between 10° and 20°. The distal surfaces 14, on the other hand, are inclined with respect to the plane of development S by an angle of between 30° and 80°, preferably of between 40° and 70°, even more preferably of between 45° and 65°. In this case, furthermore, the spacing A between the two recesses 8 is of between 25mm and 150mm, preferably it is of between 25mm and 100mm, even more preferably it is of between 30mm and 50mm.

It is specified that the above angles and distances are appropriately selected depending on the properties of the wires F of known type so as to allow optimal insertion process of the wire itself in the retaining portion 7 and its retention in the recesses 8 during the storage of the spool 1.

In addition, the particular conformation of the recesses 8 of the spool 1 according to the invention and the respective arrangement on the sidewall 3 allow the process of rolling the spool itself by the common wire feeding systems provided by 3D printers not to be altered. Such feeding systems, in fact, involve the use of special rotating rollers which, by interacting with the perimeter edge of the spools, causes them to rotate around their relevant longitudinal axis to allow the wire to be unwound.

Despite the discontinuity of the perimeter edge 4 of the spool 1, the rolling of the spool occurs without interruption or blockage.

This, in particular, occurs with reference to the second embodiment, wherein the arrangement of the distal surface 14 and the reduced distance DI makes the interruption of the perimeter edge 4 even smaller.

The operation of the present spool in performing the method according to the invention for winding the wire made of polymeric material is as follows.

The method first comprises a phase of supplying a spool 1 according to one or more of the embodiments described above and a phase of supplying a wire F made at least partly of polymeric material and of a winding machine adapted to wind the wire F around the spool 1.

Specifically, the wire can be made of at least one polymeric material selected from the list comprising: 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, polylactic acid with carbon fiber, lignin, conductive polymer, wax, acrylonitrile styrene acrylate, polypropylene, polyoxomethylene, polymethylmethacrylate, luminescent polymer, Polycarbonate/Acrylonitrile-butadiene-styrene, magnetic polymer, thermoplastic polyester elastomer, flexible polyester, poly etherimide.

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

The method then comprises a phase of loading the spool 1 onto the winding machine.

At this point, the winding machine sets the spool 1 in rotation in order to determine the position of the retaining portion. This operation is carried out by means of distance sensors arranged in the proximity of the perimeter edge 4 and adapted to detect the distance of the sidewall 3 from the sensor itself. In actual facts, as a result of rotation, when the recess 8 is arranged where the distance sensor is located, the latter detects a gap and consequently determines the position of the retaining portion 7. The distance sensor is of the type known to the engineer in the field and can be selected from the list comprising: laser sensor, photoelectric sensor, optical sensor.

Next, the method comprises a phase of fastening by interlocking a first end portion of the wire F within the spool 1. This phase is carried out by inserting the wire F within the blocking portion.

The method then comprises a phase of moving the spool 1 in rotation which is carried out in such a way as to cause the winding of the wire F around the spool. In detail, the winding machine, of a type known to the industry technician, comprises a dispensing device adapted to dispense the wire F and movable by shifting parallel to the longitudinal axis L during winding.

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

More particularly, the phase of fastening involves a first step of inserting the wire F into a first recess 8, carried out outwards from the spool 1, i.e., from the inner face 5 to the outer face 6, and a second step of inserting the wire F into the second recess 8, carried out inwards from the spool 1, i.e., from the outer face 6 to the inner face 5, around the protrusion 9.

Next, the method comprises a phase of cutting the wire F to define the second end portion P. The end portion P thus turns out to be already fastened to the spool 1.

It cannot, however, be ruled out that the phase of fastening is carried out after cutting, using a special fastening device mounted on the same winding machine. Finally, the method comprises a phase of unloading the spool 1 from the winding machine carried out subsequently to the phase of fastening.

In actual facts, once the spool 1 is removed from the winding machine, the wire F is already fastened thereto and does not require any further intervention by an operator or transfer to additional fastening machines, thus greatly reducing operating times, related costs and avoiding accidental unwinding of the wire F during such operations.

It has in practice been ascertained that the described invention achieves the intended objects, and in particular, the fact is emphasized that the spool according to the invention for the support of wires made of polymeric material allows the wire wound thereon to be effectively fastened while avoiding the use of additional packaging elements.

In addition, this spool also allows easy fastening of wires having a high level of stiffness or elasticity.

Furthermore, this spool allows for easy fastening of the wires even after a portion of the wire has been used by an end user, making it easy to store partly used spools.

Finally, this spool allows automated fastening executable on the same machine intended for winding the wire.

Claims

1) Spool (1) for the support of wires made of polymeric material comprising at least one central support (2) developing along a longitudinal axis (L) and around which a wire (F) made at least partly of polymeric material is windable and at least one pair of side sidewalls (3) associated opposite the ends of said central support (2) and each provided with a perimeter edge (4), characterized by the fact that at least one of said sidewalls (3) comprises at least one retaining portion (7) configured to retain an end portion (P) of said wire (F) wound around said spool (1), wherein said retaining portion (7) comprises at least two recesses (8) defined on said perimeter edge (4) and within which said end portion (P) is insertable.

2) Spool (1) according to claim 1, characterized by the fact that each of said sidewalls (3) develops on a relevant plane of development (S) which is substantially perpendicular to said longitudinal axis (L) and by the fact that each of said recesses (8) develops on said plane of development (S).

3) Spool (1) according to one or more of the preceding claims, characterized by the fact that each of said sidewalls (3) comprises an inner face (5) facing the inner face (5) of the other sidewall (3) and an outer face (6) facing outwards, and by the fact that each of said recesses (8) communicates outwards where said outer face (6) and said inner face (5) are located.

4) Spool (1) according to one or more of the preceding claims, characterized by the fact that said recesses (8) are arranged in succession with each other along said perimeter edge (4) and by the fact that said retaining portion (7) comprises a protrusion (9) located between said recesses (8) and defining part of said perimeter edge (4).

5) Spool (1) according to one or more of the preceding claims, characterized by the fact that said recesses (8) are arranged symmetrically to each other with respect to a median plane (M) passing through said longitudinal axis (L).

6) Spool (1) according to one or more of the preceding claims, characterized by the fact that each of said recesses (8) comprises a base surface (10) substantially planar and perpendicular to said median plane (M) and by the fact that the base surfaces (10) of said recesses (8) are substantially coplanar.

7) Spool (1) according to one or more of the preceding claims, characterized by the fact that said recess (8) comprises a pair of lateral surfaces (11), substantially contiguous to said base surface (10) and inclined with respect to the latter and by the fact that said lateral surfaces (11) are convergent with each other away from said base surface (10).

8) Spool (1) according to one or more of the preceding claims, characterized by the fact that each of said lateral surfaces (11) comprises a joining portion (12) which is adjacent to said base surface (10), said joining portion (12) having a curvilinear development.

9) Spool (1) according to one or more of the preceding claims, characterized by the fact that said pair of lateral surfaces (1 la, 1 lb) comprises a first lateral surface (I la) defined on said protrusion (9) and a second lateral surface (11b) opposite said first lateral surface (I la).

10) Spool (1) according to claim 9, characterized by the fact that said first lateral surface (I la) and said second lateral surface (11b) are symmetrical to each other with respect to a plane of symmetry of said recess (8).

11) Spool (1) according to claim 9, characterized by the fact that said first lateral surface (I la) develops along a plane passing through said longitudinal axis (L).

12) Spool (1) according to one or more of the preceding claims, characterized by the fact that said recess (8) comprises a proximal surface (13) contiguous to said first lateral surface (11), arranged in the proximity of said median plane (M) and inclined with respect thereto and by the fact that the proximal surfaces (13) of said recesses (8) are convergent with each other away from said outer face (6).

13) Spool (1) according to one or more of the preceding claims, characterized by the fact that said recess (8) comprises a distal surface (14) located between said second lateral surface (11) and said perimeter edge (4), arranged spaced apart with respect to said median plane (M).

14) Spool (1) according to claim 13, characterized by the fact that the distal surfaces (14) of said recesses (8) are divergent from each other away from their respective lateral surfaces (11).

15) Spool (1) according to claim 13, characterized by the fact that the distal surfaces (14) of said recesses (8) are divergent from each other away from said outer face (6). 16) Spool (1) according to one or more of the preceding claims, characterized by the fact that said retaining portion (7) comprises a guiding bead (15) projecting from said outer face (6), developing over the full extension of said retaining portion (7) and adapted to guide the movement of said wire (F).

17) Spool (1) according to one or more of the preceding claims, characterized by the fact that said recesses (8) are defined between said perimeter edge (4) and said guiding bead (15).

18) Method for winding a wire made of polymeric material characterized by the fact that it comprises the following phases: supplying a spool (1) according to one or more of the preceding claims; supplying a wire (F) made at least partly of polymeric material and a winding machine adapted to wind said wire (F) around said spool (1); loading said spool (1) onto said winding machine; fastening by interlocking a first end portion (P) of said wire (F) within said spool (1); moving said spool (1) in rotation in such a way as to cause the winding of said wire (F) around said spool (1); fastening said wire (F) to said retaining portion (7) carried out by means of said winding machine; cutting said wire (F) to define a second end portion (P); unloading said spool (1) from said winding machine subsequently to said phase of fastening.