WO2023285899A1

WO2023285899A1 - Double laser shot for single welding of links of a chain

Info

Publication number: WO2023285899A1
Application number: PCT/IB2022/055890
Authority: WO
Inventors: Fiorenzo SBABO
Original assignee: Sisma S.P.A.
Priority date: 2021-07-14
Filing date: 2022-06-24
Publication date: 2023-01-19

Abstract

A machine (1) and a method (100) for producing links of an ornamental chain, of the type comprising a plurality of concatenated links, by using a filiform semi-finished product (S). The machine (1) comprises a deformation and cutting means (10) configured to separate one section (S') from the remaining part of a filiform semi-finished product (S) and to bring about a first deformation of the section (S') so as to define a central arch-shaped portion and two end edges of the section (S'). The machine (1 ) further comprises a closing means (14) configured to bring about a second deformation of the section (S') so as to bring the end edges near or in abutment against each other. Furthermore, the machine (1) comprises a welding means (20 and 21) configured to weld together the end edges brought near or in abutment against each other and disposed in a welding area (A), wherein said welding means (20) is configured to generate two or more laser light beams (22) suitable for welding the end edges, generating respective distinct welding spots on the contact perimeter.

Description

“Double laser shot for single welding of links of a chain”

DESCRIPTION

Technical field

The present invention relates to a machine and a method for producing ornamental chains as well as an ornamental chain produced by means of the aforesaid machine and/or the aforesaid method, intended for use as necklaces, bracelets and the like (e.g., shoulder straps for bags)

In particular, the present invention relates to a machine and a method in the jewellery sector and/or in the costume jewellery sector for producing ornamental chains made of precious and non-precious metal material, consisting of a plurality of concatenated rings or links.

Background of the invention

Ornamental chains, in particular those made with precious materials and marketed in jewellery shops, are usually made from a filiform semi-finished product of precious material. Such a semi-finished product is divided into sections, which are mechanically shaped into rings and finally concatenated with each other.

Commonly, such a practice is carried out with the aid of special automatic devices.

In particular, the machines of a type known in the technical field pertaining to the present invention comprise a deformation and cutting means configured to separate one section from the remaining part of the filiform semi-finished product and to bring about a first deformation of such a section so as to define a central arch-shaped portion and two end edges. Such machines also comprise a closing means configured to mechanically abut the aforesaid end edges against each other, closing the ring and defining a contact surface between the two end edges as well as a contact perimeter. Furthermore, the machines of the known type comprise welding means configured to weld the abutting end edges together so as to securely join the end edges brought near or in abutment against each other by means of the previous deformation steps.

Typically, the machines of a known type comprise a laser source configured to produce a welding spot near the contact perimeter of the two end edges. Laser welding is appreciated for the flexibility of the sources, for the possibility of being able to operate without direct contact with the parts to be welded and for the improved control of the welding parameters. Some examples of machines made according to the prior art are described in US 3342029 A, IT 2018000 1349 A1 , FR 2579872 A1 , JP H0965912 A, ES 2 121 701 A1 , IT PD20060451 A1 , CN 201 275591 Y.

Flowever, although widely used, even in their most modern implementations, such machines and such a methodology for producing ornamental chains still have some structural, operational and economic/productive disadvantages which make their use not without problems.

Firstly, since the welding spot is performed substantially only on a portion of the contact perimeter, the contact surface between the two end edges can therefore only be partially welded.

It follows that the mechanical properties of the chain, and in particular the tensile strength of the single welded link, are compromised and can lead to an early breakage which is not acceptable by the market.

Secondly, some precious metals (such as silver and silver alloys) require an increase in the power of the laser beam due to the high reflection coefficient. Such an exasperation of the operating parameters compromises the final result of the weld, degrading the structure and shape of the individual links.

Furthermore, an asymmetrical arrangement of the welding spot with respect to the ring as well as a degradation of the shape of the link cause a low quality standard in terms of aesthetics and/or a low reproducibility of the piece.

Objects of the present invention In the light of the foregoing, the technical task of the present invention is to propose a machine and a method for producing ornamental chains as well as an ornamental chain produced by means of the aforesaid machine and/or the aforesaid method which overcome the drawbacks of the prior art. Notwithstanding, the object of the present invention is to provide a machine and a method for producing ornamental chains which are capable of producing an ornamental chain having high mechanical properties. Furthermore, the object of the present invention is to provide a machine and a method for producing ornamental chains capable of ensuring an excellent production in quantitative terms and at the same time ensuring a high quality standard of the individual links produced.

A further object of the present invention is to provide a machine and a method for producing ornamental chains capable of ensuring a final product having a high aesthetic quality. The specified technical task and the specified objects are substantially achieved by a machine and a method for producing ornamental chains as well as an ornamental chain produced by means of the aforesaid machine and/or the aforesaid method comprising the technical features set out in one or more of the accompanying claims or in any case comprising one or more of the features described below: further features and advantages of the present invention will become more apparent from the indicative, and thus non-limiting, description of an embodiment of a machine and a method in accordance with the present invention. Brief description of the figures Such a description will be set out below with reference to the appended drawings, which are provided solely for illustrative and therefore non limiting purposes, in which:

- figures 1A-1B illustrate in a schematic perspective view a preferred embodiment of a machine for producing ornamental chains in accordance with the present invention;

- figures 2A-2B illustrate in a schematic view from above the embodiment of the machine of figure 1 ;

- figure 3 illustrates a schematic view of a method for producing ornamental chains in accordance with the present invention.

Description of one or more preferred embodiments of the present invention

With reference to the appended drawings, with the numerical reference "1 " a machine is indicated for producing links of an ornamental chain by using a filiform semi-finished product "S".

In the present description, the term "ornamental chain" is intended to mean a chain, of the type comprising a plurality of concatenated links, intended to be used in the field of jewellery and/or costume jewellery and which is applied as a necklace, bracelet and the like (e.g., shoulder straps for bags).

Furthermore, the term "semi-finished" means an intermediate product with a filiform shape and made of metal, preferably but not exclusively of precious metal.

The machine 1 essentially comprises a deformation and cutting means 10, semi-finished product holding means 13, closing means 14 and welding means 20 and 21.

The deformation and cutting means 10 is configured to separate one section "S’" from the remaining part of the aforesaid filiform semi-finished product “S” and to bring about a first deformation of the section "S'" so as to define a central arch-shaped portion and two end edges of the section "S'", held in position by the semi-finished product holding means 13.

In other words, the deformation and cutting means 10 is configured to obtain a section "S'" from the semi-finished product "S" which has a substantially open-loop shape.

A preferred embodiment of the deformation and cutting means 10 is illustrated by way of non-limiting example in the appended drawings.

In such an embodiment, the deformation and cutting means 10 comprises a movable oval section pin which is rotatable within a fixed coaxial spiral. Such a pin, after rotation, deforms the semi-finished product "S" by wrapping it on itself, thanks also to the containing contribution of the fixed spiral for the semi-finished product.

The rotation of the pin thus brings about the advancement of the semi finished product along the rotation axis of the pin and through the fixed and guided channel of the spiral.

The deformation pin 11 can in some cases have a decreasing section along such an advancement direction so as to favour a progressive deformation of the semi-finished product "S".

The cutting means 12 can comprise two cutting tools, one vertical and one horizontal, operatively disposed downstream of the deformation pin 11 and configured to bring about the aforesaid separation of the section "S’" from the remaining part of the semi-finished product "S".

The deformation and cutting means 12 can also advantageously comprise guiding means 13 suitable for retaining the section S1 after the cutting from the semi-finished product S, for advancing the section S’ towards a welding area "A" and for retaining the section near such a welding area "A".

Advantageously, moreover, the guiding means 13 can be configured to advance the section "S’" towards the closing means 14, suitable for bringing the edges of the section S1 near each other and closing them after the cutting step. The closing means 14 is configured to bring about a second deformation of the section "S’" so as to bring said end edges of the section "S'" near or in abutment against each other, thereby defining a contact perimeter.

In other words, the closing means 14 brings about a further bending of the section "S’" so that the end edges are mutually brought near each other, coming into contact with each other and defining a contact surface.

Again, the closing means 14 is configured to bring about a mechanical closure of the ring.

Again, the closing means 14 can keep the section "S" already closed and stable while the rotation of the guiding means 13 brings about a different shape of the same ring.

The closing means can comprise two bending grippers configured to retain the respective end edges of the section "S1". In particular, such bending grippers are movable between a distanced disengagement configuration and a neared configuration in which said bending grippers bring the end edges near or in abutment against each other, defining the aforesaid contact perimeter.

The welding means 20, 21 is configured to weld together said end edges brought near or in abutment against each other and disposed in the welding area "A"

Preferably the welding means 20, 21 comprises two distinct laser focusers, or other system, each configured to emit a respective laser beam. According to a particular aspect of the present invention, the welding means 20 and 21 is configured to generate, preferably independently, two light beams (one from each focuser) so as to focus a respective laser beam from its own source (if there are two laser sources: one for each focuser) or from a single source with division of the beam generated with an appropriate "beamsplitter" into two fibres towards said laser focusers. The two laser beams produced are suitable for welding end edges, generating respective and distinct welding spots on the contact perimeter. Advantageously, thereby, since the two end edges are joined in two or more welding spots obtained on distinct portions of the contact perimeter, an optimal weld is obtained.

In fact, the mechanical properties of the chain, and in particular the tensile strength of the single link, are considerably increased.

Furthermore, the use of two or more laser light beams 22 ensures that, during the operations, each laser light beam 22 can have a lower overall power so as not to damage the structure of the single link and/or so as not to degrade the shape thereof.

In other words, while operating with reduced overall power with respect to a single laser beam (or single shot), the two or more laser light beams 22 ensure being able to substantially weld the entire contact surface between the two end edges.

In the present description, the term "distinct" is intended to indicate that the welding spots are disposed on the contact perimeter in a position sufficiently distant to not be adjacent or partially overlapping.

Furthermore, the expression "welding spots" is intended to mean that the welding is carried out by keeping the section "S1 closed in a loop" and the welding means 20 and 21 mutually immovable so that each laser beam operates only on a respective "spot" or portion of the contact perimeter, consequently producing the aforesaid welding spots.

The welding means 20 and 21 can comprise one or more laser sources suitable for generating the aforesaid laser beams.

In other words, the machine 1 can comprise a single laser light source configured to generate the aforesaid two or more laser light beams 22 that are divided by the "beamsplitter" and then emitted by the welding means. Alternatively, as illustrated in the appended drawings showing a preferred but non-limiting embodiment of the machine 1, the welding means 20 and 21 can comprise two or more laser sources each configured to generate a respective laser light beam 22 emitted by a respective welding means.

In this case, the welding means 20, 21 comprises two independent optical resonators (or more in the case of multiple laser beams) each used to generate a respective laser beam. Furthermore, the welding means (20, 21) comprises laser beam regulation means configured to independently regulate the power and/or duration and/or waveform of each laser beam. It is thereby advantageously possible to regulate each "shot" independently according to the welding needs.

In detail, the regulation means is configured to operate on said resonators to perform independent regulations for the generation of the laser beams. According to an aspect of the present invention, the laser sources and the welding means 20, 21 are operatively stationary.

Furthermore, the laser sources and the welding means 20, 21 can be configured to generate respective stationary laser light beams 22. According to a further aspect of the present invention, the welding means 20, 21 is disposed around the welding area "A" so that the welding spots are disposed on portions angularly distanced from the contact perimeter. According to a preferred embodiment, illustrated by way of non-limiting example only, the welding means 20, 21 comprises laser focusers also indicated by the numbers 20, 21.

In such an embodiment, the laser focusers 20, 21 are disposed in a substantially opposite position around the welding area "A", preferably opposite with respect to a lying plane of the ring to be welded, so as to generate welding spots on the contact perimeter on portions substantially opposite each other.

Alternatively, if there are three welding means, they are angularly equally distributed around the welding area "A" so as to achieve respective welding spots angularly equally distributed on the contact perimeter. Advantageously, thereby, the distribution of the welding spots ensures optimal mechanical performance as well as a better aesthetic of the entire chain since the welding spots are disposed symmetrically and/or equally distant on the contact perimeter. According to a further aspect of the present invention, the welding means 20, 21 is substantially identical to each other and disposed at the same distance with respect to the welding area "A".

Furthermore, during the operations, the external laser source(s) have the possibility of modifying the operative parameters, such as the power of the laser light beam 22 to benefit a balanced welding.

Furthermore, the welding means 20, 21 has the possibility of adjusting the focal distance to benefit a balanced welding.

According to a further aspect, the laser sources are configured to operate the respective welds simultaneously.

Advantageously, such a technical feature further improves the welding process. Furthermore, such a technical feature ensures optimal performance in terms of efficiency and quality of the links produced. According to a further aspect of the present invention, the welding means 20, 21 can be configured to direct the non-parallel and in particular converging laser light beams 22.

For example, at least one of the welding means 20, 21 can be disposed at a different height with respect to the welding area "A".

In the preferred embodiment, illustrated by way of non-limiting example in the appended drawings, one of the welding means 21 (on the left 21 in the figure) is disposed so as to result in a substantially raised position with respect to the section "S1 closed ring" to be welded. In particular, the welding means is oriented so that the respective laser light beams 22 are at least partially facing downwards and in particular in the direction of the welding area "A".

The invention further relates to a method 100 for producing a link of an ornamental chain of the type comprising a plurality of concatenated links by using a filiform semi-finished product "S".

Preferably but not exclusively, such a method 100 can be implemented by the aforesaid machine 1. Firstly, the method 100 comprises a step "a" in which a bent section "S’" obtained by cutting and bending a portion of a filiform semi-finished product "S" is provided. In particular, the bent section "S’" has an arch shaped portion and two end edges.

Advantageously, such a step "a" can be performed by the aforesaid deformation and cutting means 10.

The method 100 comprises a subsequent step "b" in which the bent section "S’" is further deformed to bring about a reciprocal nearing or abutting of the end edges, thus defining a contact perimeter. Advantageously, such a step "b" can be carried out by the aforesaid closing means.

Subsequently, the method 100 comprises a step "c" in which the neared or abutting end edges are welded to each other at the contact perimeter, generating distinct welding spots on the contact perimeter, preferably disposed in a position substantially opposite each other.

Advantageously, such a welding step "c" can be performed by the aforesaid welding means 20, 21.

In particular, the welding spots can be made by respective external laser sources that generate focused laser beams through the stationary welding means 20, 21.

According to a further aspect, in the welding step "c" the distinct welding spots can be generated simultaneously or at a later time.

Advantageously, such a method 100 allows to obtain an ornamental chain whose individual links have high mechanical properties.

In fact, the arrangement of the welding spots on the contact perimeter ensures an optimal union of the end edges to benefit the mechanical properties, and in particular the tensile strength.

Furthermore, for the same reason, it is possible to operate with a reduced power since the two or more distinct welding spots ensure the union of a sufficient contact surface between the two end edges to benefit the structural integrity of the single link. Finally, the substantially symmetrical arrangement of the welding spots as well as the low power employed ensure a high aesthetic result.

The invention further relates to an ornamental chain of the type comprising a plurality of concatenated links, in particular produced by means of the aforesaid machine and/or by means of the aforesaid method.

In particular, the links of such a chain have at least two distinct welding spots at a contact perimeter between opposite end edges of a filiform section "S" forming the link.

Preferably, there are two such welding spots disposed in a position substantially opposite each other.

The present invention achieves the intended objects, eliminating the drawbacks highlighted by the prior art: in this regard, it should firstly be noted that the machine 1 and the method 100 as described and/or claimed allow to obtain an ornamental chain with optimal mechanical properties as well as ensure preserving the structure and the material of the individual links forming the chain.

It should also be noted that the machine 1 and the method 100 as described and/or claimed allow to obtain high production while ensuring a high quality standard. Again, it should be noted that the machine 1 and the method 100 as described and/or claimed allow to obtain an ornamental chain having a high aesthetic value.

Claims

1. A machine (1) for producing links of an ornamental chain, of the type comprising a plurality of concatenated links, by using a filiform semi finished product (S); said machine (1) comprising:

- a deformation and cutting means (10) configured to separate one section (S’) from the remaining part of a filiform semi-finished product (S) and to bring about a first deformation of said section (S) so as to define a central arch-shaped portion and two end edges of said section (S);

- a closing means configured to bring about a second deformation of said section (S’) so as to bring said end edges near or in abutment against each other, thereby defining a contact perimeter;

- welding means (20, 21) configured to weld together said end edges brought near or in abutment against each other and disposed in a welding area (A); said welding means (20, 21) is configured to independently generate two or more laser light beams (22) suitable for welding said end edges, generating respective distinct welding spots on said contact perimeter; characterised in that said welding means (20, 21) comprises two or more laser focusers (20, 21), each configured to emit a respective laser light beam (22); said two or more laser focusers being disposed around said welding area (A) so that said welding spots are disposed on angularly distanced portions of said contact perimeter.

2. The machine (1) according to claim 1, wherein said laser focusers (20, 21) are disposed in a substantially opposed position around said welding area (A) so as to direct said laser light beams (22) onto said contact perimeter in order to generate welds disposed on portions that are substantially opposite each other.

3. The machine (1) according to any one of the preceding claims, wherein said laser sources and welding means (20, 21) are operatively stationary.

4. The machine (1) according to any one of the preceding claims, wherein the welding means (20, 21) is configured to emit respective stationary laser light beams (22).

5. The machine (1) according to any one of the preceding claims, wherein the welding means (20, 21) comprises two independent resonators, each responsible for generating a respective laser beam.

6. The machine (1) according to any one of the preceding claims, wherein the welding means (20, 21) comprises laser beam regulation means configured to regulate the power and/or the duration of each laser beam independently.

7. The machine (1) according to claim 6 when dependent on claim 5, wherein said regulation means is configured to operate on said resonators to perform independent regulations for the generation of laser beams.

8. The machine (1) according to any one of the preceding claims, wherein said welding means (20, 21) is configured to produce the respective welds simultaneously.

9. The machine (1) according to any one of claims 1 to 7, wherein said welding means (20, 21) is configured to operate the respective welds in a temporally deferred manner.

10. The machine (1) according to any one of the preceding claims, wherein said welding means (20, 21) is configured to emit respective laser light beams (22) that are not parallel, and are in particular convergent.

11. A method (100) for producing a link of an ornamental chain of the type comprising a plurality of concatenated links, by using a filiform semi finished product (S), by means of the machine (1) according to any one of the preceding claims, comprising the following steps:

(a) providing a bent section (S’) obtained by cutting and bending a portion of a filiform semi-finished product (S), wherein said bent section (S’) has an arch-shaped portion and two end edges;

(b) further deforming said bent section (S’) in order to bring about a reciprocal nearing or abutting of said end edges, thus defining a contact perimeter;

(c) independently generating two or more laser light beams (22) suitable for welding together said neared or abutting end edges at said contact perimeter, thus generating two or more distinct welding spots on said contact perimeter, preferably disposed in a position substantially opposite each other.

12. The method (100) according to claim 11, wherein in said welding step (c) said distinct welding spots are generated simultaneously or in a temporally deferred manner.

13. The method (100) according to claim 11 or 12, wherein said welding spots are produced by means of respective stationary laser sources and welding means (20, 21).

14. An ornamental chain of the type comprising a plurality of concatenated links, in particular produced by means of a machine (1) according to any one of the preceding claims 1 to 10 and/or by means of the method (100) according to any one of the preceding claims 11 to 13, wherein the links of said chain have at least two distinct welding spots at a contact perimeter between opposite end edges of a filiform section (S’) forming said link.

15. The chain according to claim 14, wherein there are two said welding spots disposed in a position substantially opposite each other.