WO2025104758A1

WO2025104758A1 - Electroforming machine

Info

Publication number: WO2025104758A1
Application number: PCT/IT2023/000035
Authority: WO
Inventors: Diego LIBERATORI
Original assignee: Italfimex Srl
Current assignee: Italfimex Srl
Priority date: 2023-11-15
Filing date: 2023-11-15
Publication date: 2025-05-22
Anticipated expiration: 2026-05-15
Also published as: WO2025104758A8

Abstract

An electroforming machine, particularly for manufacturing objects, of the type of chains or necklaces, comprising a plurality of mutually coupled links or rings. The machine (1) comprises at least: a supporting structure (2) for one or more matrices (A) replicating the shape of the objects to be produced, to be coated by electrodeposition, a tub (3), configured to fill it with a galvanic bath (B), a first terminal (4a) and a second terminal (4b), constituting a negative and a positive pole respectively, connected to a power supply (4) and configured to subject the galvanic bath (B) to an electric current. The structure (2) comprises at least means (5) for moving a suspended mass (6) comprising a scaffold (7) for supporting a rotating element (8), configured to support the matrices (A) and connectable to the negative pole; the movement means (5) are configured for moving the suspended mass (6) at least between a working position, in which the element (8) is placed proximate to the tub (3) for the immersion of a portion of the matrices (A) in the bath (B), and a checking position, in which the element (8) is spaced from the tub (3), in order to keep the matrices (A) completely outside of the bath (B). Furthermore, the machine (1) comprises at least one device (9) for weighing the suspended mass (6), which can be activated when the suspended mass (6) is in the checking position.

Description

ELECTROFORMING MACHINE

The present invention relates to an electroforming machine, a related method and a respective use.

Galvanic electrodeposition is a well-known method widely used in industry, by means of which one or more metals can be deposited on an object capable of conducting electric current, thus forming one or more layers of various thicknesses.

In greater detail, in some applications the finished product is constituted by the object and by the metallic layer obtained by electrodeposition, which covers the object itself for decorative, protective (against corrosion in particular) or other purposes.

Sometimes the electrodeposition step is instead performed on a matrix and is conveniently prolonged in time until a layer is obtained which, in addition to being an exact replica of the matrix, has a considerable thickness: the matrix is then removed and the layer thus obtained is a kind of self-supporting shell that in practice constitutes the finished product (lacking indeed the matrix). In the latter case, as well known, the method is called "electroforming."

Thus, electroforming can be employed effectively in a variety of contexts and for example in the field of jewelry or fashion, but it is not free from drawbacks, in particular in the provision of chains and the like, composed of a plurality of links or rings coupled together in pairs.

In such cases, in fact, during the increase in thickness that occurs during the electroforming process, the various links tend to weld to each other, compromising the quality of the finished product.

To obviate this problem, according to known methods, only individual links or small pieces are provided by electrodeposition and are connected to each other later to form indeed the chain; the production of chains directly by electroforming is instead limited to cases where a low thickness of galvanic deposition is required, where there is no risk of link welding as a result of galvanic growth.

When, therefore, greater thicknesses are desired, the need to provide at a later time the assembly of the individual links or individual portions is a considerable complication in the production process, causing an unwelcome time increase and a significant rise in costs.

The aim of the present invention is to solve the above problems by providing a machine that allows to provide by electroforming entire chains (or similar items) of any length and with any thickness of the deposited material.

Within the scope of this aim, an object of the invention is to devise a method that allows to provide by electroforming whole chains (or similar objects) of any length and with any thickness of the deposited material.

Another object of the invention is to provide by electroforming a whole chain without the risk of welding the individual links together.

Another object of the invention is to provide by electroforming a whole chain, ensuring maximum precision in the size of the thickness of deposited material.

Another object of the invention is to provide a machine and devise a method that ensure high reliability of operation.

Another object of the invention is to provide a machine that adopts a technical and structural architecture that is alternative to those of machines of the known type.

Not least object of the invention is to provide a machine and devise a method that can be obtained easily starting from commonly commercially available elements and materials.

Still another object of the invention is to provide a machine and devise a method having low costs and of assured application.

This aim and these and other objects that will become better apparent hereinafter are achieved by a machine according to claim 1, a method according to claim 13, and a use according to claim 15. Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the machine and the method according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a front lateral axonometric view of the machine according to the invention;

Figure 2 is a lateral elevation view of the machine of Figure 1;

Figure 3 is a top view of the machine of Figure 1;

Figures 4 to 6 are sectional views of the operation of the machine of Figure 1, taken along the plane IV-IV of Figure 3;

Figure 7 is a front lateral perspective view of the suspended mass of the machine of Figure 1;

Figure 8 is a rear lateral axonometric view of the suspended mass of Figure 7;

Figure 9 is a rear view of the suspended mass of Figure 7;

Figure 10 is a top view of the suspended mass of Figure 7;

Figure 11 is a sectional view of Figure 10, taken along the plane XI- XI;

Figure 12 is a block diagram of the method according to the invention.

With reference to the figures, the reference numeral 1 generally designates an electroforming machine, particularly but not necessarily designed for the production of chains or necklaces (whole or portions) or in any case of objects comprising a plurality of mutually coupled links or rings. In fact, as will become better apparent hereinafter, it is precisely when the machine 1 is used for the production of objects of the type indicated above that the particularities of the invention are enhanced, but the protection claimed herein extends also to the electroforming of other products, as required by the case. Thus, the machine 1 comprises first of all a supporting structure 2 for one or more matrices A replicating the shape of the objects to be produced, said matrices A being designed to be coated by electrodeposition indeed by virtue of the machine 1.

Moreover, the machine 1 comprises a tub 3 that is configured to be filled with a galvanic bath B (an aqueous solution of the metal to be deposited).

In addition, the machine 1 comprises a first terminal 4a and a second terminal 4b, which constitute a negative pole and a positive pole, respectively, and are connected to a power supply 4 (and/or a current rectifier) and configured to subject the galvanic bath B to an electric current. The power supply 4 and the poles 4a, 4b are shown only schematically exclusively in Figure 1 but are nevertheless chosen also of a per se known type.

According to established methods, the galvanic electrodeposition technique performed by the invention causes an electrolytic reaction in the tub 3 after immersing the matrices A to be coated in the galvanic bath B. By applying a potential difference to the terminals 4a, 4b, a flow of ions of the metal to be deposited is generated which gradually accumulates on the matrices A, forming the desired coating layer (indeed by electrodeposition).

In the case of electroforming (for which the machine 1 is specifically designed), this electrodeposition step is conveniently prolonged in time until a layer is obtained which, in addition to being an exact replica of the matrix A on which it has been deposited, has a considerable thickness: the matrix A is then removed and the layer thus obtained is a sort of self-supporting shell that in fact constitutes the object that one intended to produce (indeed without the matrix A).

Up to this point, in any case, these are devices and concepts that are well-known in the art and which therefore shall not be dwelt upon further.

According to the invention, the structure 2 comprises at least means 5 for moving a suspended mass 6, which in turn comprises a scaffold 7 that has the task of supporting an element 8 which rotates (with respect to said scaffold 7).

Typically, the element 8 has a cylindrical or axially symmetrical contour and rotates about an axis of rotation C (which is usually but not necessarily horizontal) that coincides with its longitudinal axis of symmetry, but providing the element 8 in other shapes is not excluded.

The element 8 is configured to support the matrices A and can be connected to the negative pole. The positive pole can be connected for example to one or more electrodes immersed in the bath B.

As shown, the objects to be produced are preferably chains or necklaces, and therefore the matrices A have a similar shape: as Figure 8 clearly shows, for example, each of the latter can simply be wrapped around the element 8 and left dangling with its lower portion below the latter.

The movement means 5 are configured to move the suspended mass 6 at least between a working position and a checking position.

In the working position (for example, the one assumed by the suspended mass 6 in Figure 4), the element 8 is located proximate to the tub 3 so as to immerse a portion of the matrices A in the bath B. The immersed portion is indeed the lower one, below the element 8.

In the checking position (for example, the one assumed by the suspended mass in Figure 6), the element 8 is spaced from the tub 3 to keep the matrices A completely outside the bath B (with the purposes that will be described hereinafter).

Obviously, electrodeposition is provided when the suspended mass 6 is in the working position.

Typically, the movement of the suspended mass 6 is a vertical translation (although providing other types of movement by virtue of the movement elements 5 is not excluded): as in the accompanying figures, the suspended mass 6, by descending, can bring the element 8 to skim the bath B (in the working position); when electrodeposition (electroforming) is completed, the upward movement allows to make the matrices A emerge completely, in order to pick them up and/or subject them to the other treatments that will be described hereinafter.

According to the invention, the machine 1 furthermore comprises at least one device 9 for weighing the suspended mass 6 (and therefore any matrices A hanging from the element 8), which can be activated when said suspended mass 6 is in the checking position.

The invention is thus able to achieve its aim: in the working position, the rotation of the element 8 causes a constantly changing portion of the matrices A to be immersed in the bath B, in order to allow the gradual forming of the entire coating layer (by indeed rotating the element 8 continuously). The rotation keeps the individual links of the chains or necklaces in motion, averting the danger that they might weld together as the thickness of the progressively deposited metal coating layer grows. The layer increases its thickness in the contact area as well, uniformly, and generally throughout the entire surface of the chain or in any case of the matrix A. In this sense, the continuous rotary motion allows to avoid having regions with different current density and therefore inhomogeneity in the deposited layer.

The weighing performed by the device 9, when the mass 6 is brought to the checking position (also and especially before completing electroforming), allows to check the thickness of the layer deposited up to that point, and this, particularly for pure metal deposits and for metal alloys, guarantees precisely that the desired average thickness is obtained. In fact, given the surface area of the chain or, in any case, of the matrix A and the density of the metal or alloy of metals deposited, it is possible to easily calculate the thickness obtained as a function of the weight detected and/or, equivalently, the weight to be obtained as a function of the desired thickness. In particular, in an embodiment of considerable practical interest, shown in the accompanying figures by way of non-limiting example of the invention, the element 8 comprises a central shaft 10 and a plurality of axial stems 11. The shaft 10 can be connected to the negative pole (to the first terminal 4a) and is extended along the axis of rotation C (i.e., coaxially to the latter). The axial stems 11 are distributed around the shaft 10 along an imaginary cylinder arranged coaxially to the axis of rotation C and are configured to support the matrices A (i.e., the latter are in contact indeed with the stems 11, which support them).

The shaft 10 and the stems 11 are made of electrically conducting materials and are mutually connected (electrically), so as to obtain the connection to the negative pole also for the matrices A hanging from the element 8.

Even more particularly, and with further reference to the preferred but not exclusive embodiment shown in the accompanying figures, the element 8 comprises a plurality of annular plates 12, which are (transversely) anchored to the stems 11 at different longitudinal distances, so as to form respective seats for receiving corresponding matrices A, between pairs of adjacent plates 12.

The plates 12 ensure proper spacing between the matrices A during the rotation of the element 8 and/or the movement of the suspended mass 6, averting the danger that they might come into contact with each other due to undesirable relative movements along the direction identified by the axis of rotation C.

In the preferred but not exclusive embodiment of the invention, the movement means 5 comprise a drive unit 13 (an electric motor, for example) for at least one linear actuator 14, which is configured to raise and lower the suspended mass 6 and accordingly provide movement (preferably vertical translation, as anticipated in the preceding pages) at least between the working position and the checking position. Preferably, as in the accompanying figures, the drive unit 13 actuates two laterally adjacent linear actuators 14 (there could also be more).

In this context, usefully the weighing device 9 can be mounted on the linear actuator 14 (on one of them or on each of them, as in the accompanying figures).

More particularly, the actuator 14 may comprise (or be constituted by) a lifting jack, which in turn comprises a rod 15, which can translate along a vertical axis and supports the mass 6. The weighing device 9 may comprise (or be constituted by) a load cell mounted substantially at the end of the rod 15 that faces the mass 6. In this way, the load cell in practice detects only the weight of mass 6, averting the risk that its reading might be perturbed by other factors or components.

In any case, the possibility to provide devices 9 of another type, whether placed at the end of the rod 15 that faces the mass 6 or elsewhere, is not excluded.

In the preferred but not exclusive embodiment of the machine 1 according to the invention, the structure 2 comprises a frame (which rests on the ground and is in practice fixed) provided with two posts 16a connected in an upward region by a crossmember 16b, which supports (or holds) the movement means 5 (the drive unit 13 and the actuators 14).

Usefully, the suspended mass 6 may comprise a motor assembly 17 which is supported by the scaffold 7 and is configured to actuate the rotation of the element 8 (about the axis of rotation C).

In particular, the motor assembly 17 may comprise a gearmotor 18 associated, by virtue of at least one motion transmission element 19, with the shaft 10.

More particularly, in the solution of the accompanying figures, the output of the gearmotor 18 is coupled to the first of two mutually meshing transmission elements 19 (two gears), which in turn are mechanically connected to the shaft 10. Advantageously, the machine 1 comprises first and second connection means, which are configured to provide the automatic connection of the motor assembly 17 to a power source 20 (so as to allow the latter to supply power to the former), when the suspended mass 6 is arranged in the working position and in a dripping position, respectively (Figure 5), in which the element 8 (as in the checking position) is spaced from the tub 3, in order to keep the matrices A completely out of the bath B. As in the accompanying figures, preferably the dripping position is distinct from the checking position (in the former, the suspended mass 6 is at a higher vertical elevation).

The source 20 might also be external to the machine 1 or in any case also of a known type (and for this reason, too, it is shown only schematically and only in Figure 2).

By virtue of the first means and the second means, both in the working position and in the dripping position it is possible to actuate the rotation of the element 8, in the first case to perform the electrodeposition process (electroforming) and in the second case to allow the dripping of the matrices A that hang from the element 8 before performing weighing (otherwise the drops of solution might affect the reading).

In particular, the first connection means may comprise a first connector 21 that protrudes from one side of the scaffold 7 (and is connected to the motor assembly 17) and a second connector 22 that is located to the side of the tub 3. The second connector 22 is connected to the source 20 and, by virtue of its position with respect to the scaffold 7 and the trajectory imposed thereon by the movement means 5, automatically comes into electrical contact with the first connector 21 when the suspended mass 6 is in the working position (Figure 4).

In particular, the second connection means may comprise a pin 23 which protrudes from the scaffold 7 (and is connected to the motor assembly 17) and a terminal strip 24 which is connected to the power source 20 and hangs from a plate 25 which extends in a downward region from the crossmember 16b of the frame.

By virtue of its position with respect to the scaffold 7 and the trajectory imposed on it by the movement means 5, the terminal strip 24 automatically comes into electrical contact with the pin 23 when the suspended mass 6 is in the dripping position (Figure 5).

In addition to the machine 1 described so far, an electroforming method 100, performed by using said machine 1, is also a subject matter of the protection claimed herein.

The method 100 is particularly intended for electroforming objects, of the type of chains or necklaces (whole or portions), comprising a plurality of mutually coupled links or rings. In any case, the possibility of performing the method 100 for electroforming objects of other types is not excluded (and in any case falls within the protective scope claimed herein).

The method 100 according to the invention provides at least, in a (preliminary, preparatory) step a., for filling the tub 3 with a galvanic bath B and for hanging from the element 8 one or more matrices A replicating the shape of the objects that one wishes to produce.

It is specified that the protective scope claimed herein extends to the use of the machine 1 and the execution of the method 100 for coating any number of matrices A (equal to or greater than one). Whenever "matrices A" (plural) is or has been referenced in the present description, the concepts expressed should be understood to refer, mutatis mutandis, also to "a matrix A" (singular).

Moreover, the method 100 provides, in a step b., for bringing the suspended mass 6 to the working position so as to immerse a (lower) portion of the matrices A to be coated in the galvanic bath B. Once such a working position has been reached, as shown, the power supply of the motor assembly 17 is ensured by the first connection means.

The method 100 according to the invention then provides, in a step c., for starting the electroforming and thus subjecting the galvanic bath B to an electric current while the element 8 is rotated about its own axis of rotation C (varying with the rotation the portion inside the bath B and thus) to cyclically immerse the entire matrices A in the bath B, so as to progressively coat them with a metallic layer, indeed by electrodeposition.

Moreover, the method 100 according to the invention provides, in a step d. to be performed at least during the execution of step c., for temporarily bringing the suspended mass 6 to the checking position and to perform at least one weighing cycle by means of the device 9, so as to verify the value of the thickness of the metallic layer obtained up to that point.

Step d. can be repeated at will for as many times as deemed appropriate.

Thus, the method 100 according to the invention provides, in a step e. to be performed when the desired value of the thickness of the metallic layer is reached, for picking up the matrices A coated with the obtained metallic layer. In other words, said step e. provides for removing them from the element 8.

The attainment of the desired value can be checked as a function of the last weighing performed and/or by taking into account the growth rate of the thickness over time (and thus calculating the expected growth from the last weighing performed). In any case, a final weighing can always be performed before considering the electrodeposition completed.

The method 100 subsequently provides for removing the matrices A (for example according to any one of the methods known in the field of electroforming) to obtain the objects to be produced, which in fact are constituted only by the coating layer obtained (a self-supporting shell).

In an embodiment of the invention of particular practical interest, which however does not limit the invention, the weighing cycle provides at least, in a step dl., for bringing the suspended mass 6 to the dripping position. Once this dripping position is reached, as shown, the power supply of the motor assembly 17 is ensured by the second connection means.

The weighing cycle then provides at least, in a step d2., for rotating the element 8 (about the axis of rotation C) to cause the dripping of the at least partially coated matrices A. In this way, any drops of solution caught between the matrices A are made to fall (into the tub 3 below).

The weighing cycle then provides at least, in a step d3., for stopping the rotation of the element 8 and bringing the suspended mass 6 to the checking position.

The weighing cycle then provides at least, in a step d4., for performing weighing by means of the device 9.

At the end of step d4. it is possible to return the suspended mass 6 to the working position and restart the electrodeposition step c. or consider the latter completed, if the desired thickness has already been reached, thus moving on to the final steps of the method 100 (steps e. and f.).

Furthermore, a subject matter of the protection claimed herein is also the use of the machine 1 as shown so far for the electroforming of objects of the type of chains and necklaces, comprising a plurality of mutually coupled links or rings.

In any case, the possibility of using the machine 1 for electroforming objects of other types is not excluded (and in any case falls within the protective scope claimed herein).

The operation of the machine 1 according to the invention has already been described in the preceding pages: in fact, it has been shown that the machine 1 allows to coat one or more matrices A hanging from the element 8 with a metallic layer, by virtue of to the galvanic bath B in which they are (partially) immersed.

The scaffold 7 that supports the element 8 (and thus the matrices A) is lifted or lowered into the bath B by the movement means 5, which also support the weighing device 9.

As shown, weighing relates only to the suspended mass 6 and this prevents perturbing factors from altering the reading. It should be noted in this regard that the scaffold 7 may comprise a crossmember 26 that accommodates only the necessary cables, so as to prevent other cables or wires from interfering with weighing.

As long as the suspended mass 6 is in the working position, the rotation of the element 8 allows to immerse progressively the entire outer surface of the matrices A in the bath B: by prolonging the activity for the appropriate time, electrodeposition of the coating layer is thus obtained and can be made to grow (in thickness) to the desired value.

To check indeed the thickness, and to obtain an absolutely precise result in this respect, it is possible to perform one or more weighings of the suspended mass 6 by virtue of the device 9. To do this, the suspended mass 6 is first lifted to the dripping position, to remove any drops of solution that may have remained trapped, and then is brought to the checking position, where the weighing takes indeed place. The choice of having separate dripping and checking positions allows to disconnect the element 8 from the power source 20 (which is necessary for the rotation of the element 8 during dripping) when weighing is performed.

Once the desired thickness is reached, the matrices A coated with the obtained layer are removed and then the matrices A are eliminated, so as to obtain (indeed by electroforming) the finished product constituted by the layer alone.

In practice it has been found that the invention fully achieves the intended aim, since it makes it possible to provide by electroforming and with maximum precision whole chains, portions thereof or other objects of any length and with any thickness of the deposited material.

The machine 1 allows to obtain galvanic coatings up to high thickness on chains of considerable length without the links welding to each other during the growth of the thickness of the galvanic coating (since during growth the matrices A are continuously rotated). The machine according to the invention also takes into account the optimization of current distribution; in fact, the electrical contact is provided to the shaft 10 arranged at the center of the element 8, allowing uniform distribution of said current over all the hanging matrices A. It is also possible to provide contact at any point of the element 8 (of shaft 10).

Moreover, the machine according to the invention is absolutely versatile, since it allows to obtain objects with lengths that are different from those originally intended by design, thus proving to be absolutely suitable for the electroforming of any type of chain.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; all the details may furthermore be replaced with other technically equivalent ones.

In the exemplary embodiments shown, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other exemplary embodiments.

In practice, the materials used, as well as the dimensions, may be any according to the requirements and the state of the art.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. An electroforming machine, particularly for manufacturing objects, of the type of chains or necklaces, comprising a plurality of mutually coupled links or rings, said machine (1) comprising at least:

- a supporting structure (2) for one or more matrices (A) replicating the shape of the objects to be produced, to be coated by electrodeposition,

- a tub (3), configured to fill it with a galvanic bath (B),

- a first terminal (4a) and a second terminal (4b), constituting a negative and a positive pole respectively, connected to a power supply (4) and configured to subject the galvanic bath (B) to an electric current, characterized in that said structure (2) comprises at least means (5) for moving a suspended mass (6) comprising a scaffold (7) for supporting a rotating element (8), configured to support the matrices (A) and connectable to said negative pole, said movement means (5) being configured for moving said suspended mass (6) at least between a working position, in which said element (8) is placed proximate to said tub (3) for the immersion of a portion of the matrices (A) in the bath (B), and a checking position, in which said element (8) is spaced from said tub (3) in order to keep the matrices (A) completely outside of the bath (B), and in that it comprises at least one device (9) for weighing said suspended mass (6), which can be activated when said suspended mass (6) is in said checking position.

2. The machine according to claim 1, characterized in that said element (8) comprises a central shaft (10), connectable to said negative pole and extended along the axis of rotation (C) of said element (8), and a plurality of axial stems (11), distributed around said shaft (10) along an imaginary cylinder arranged coaxially to said axis of rotation (C) and configured to supporting the matrices (A), said shaft (10) and said stems (11) being made of electrically conducting materials and being mutually connected.

3. The machine according to claim 2, characterized in that said element (8) comprises a plurality of annular plates (12), anchored to said stems (11) at different longitudinal distances to define respective seats for receiving corresponding matrices (A) between pairs of said adjacent plates (12).

4. The machine according to one or more of the preceding claims, characterized in that said movement means (5) comprise a drive unit (13) of at least one linear actuator (14), configured for the lifting and lowering of said suspended mass (6) and the consequent movement at least between said working position and said checking position.

5. The machine according to claim 4, characterized in that said weighing device (9) is mounted on said at least one linear actuator (14).

6. The machine according to claim 5, characterized in that said at least one actuator (14) comprises a lifting jack, comprising a rod (15) which can translate along a vertical axis and supports said suspended mass (6), said weighing device (9) comprising a load cell substantially mounted at the end of said rod (15) that faces said suspended mass (6).

7. The machine according to one or more of the preceding claims, characterized in that said structure (2) comprises a frame provided with two posts (16a) connected in an upward region by a cross-member (16b) which supports said movement means (5).

8. The machine according to one or more of the preceding claims, characterized in that said suspended mass (6) comprises a motor assembly (17) supported by said scaffold (7) and configured to actuate the rotation of said element (8).

9. The machine according to claim 8, characterized in that said motor assembly (17) comprises a gearmotor (18) associated, by means of at least one motion transmission element (19), with said shaft (10).

10. The machine according to claim 8 or 9, characterized in that it comprises first connection means and second connection means, configured for automatically connecting said motor assembly (17) to a power source (20) when said suspended mass (6) is arranged in said working position and in a dripping position, respectively, wherein said element (8) is spaced from said tub (3), in order to keep the matrices (A) completely outside the bath (B), said dripping position being preferably distinct from said checking position.

11. The machine according to claim 10, characterized in that said first connection means comprises a first connector (21) protruding from a side of said scaffold (7) and a second connector (22) placed to the side of said tub (3), connected to said power source (20) and automatically placed in electrical contact with said first connector (21) when said suspended mass (6) is in said working position.

12. The machine according to claim 10 or 11, characterized in that said second connection means comprises a pin (23) which protrudes from said scaffold (7) and a terminal strip (24) which is connected to said power source (20), said terminal strip (24) being suspended from a plate (25) extending in a downward region from said cross-member (16b) of said frame and being placed automatically in electrical contact with said pin (23) when said suspended mass (6) is in said dripping position.

13. An electroforming method particularly for objects, of the type of chains or necklaces, comprising a plurality of mutually coupled links or rings, by means of a machine (1) according to one or more of the preceding claims, which provides for at least the following steps: a. filling the tub (3) with a galvanic bath (B) and hanging from the element (8) one or more matrices (A) replicating the shape of the objects to be manufactured, b. bringing the suspended mass (6) to the working position in order to immerse a portion of the matrices (A) to be coated in the galvanic bath (B), c. subjecting the galvanic bath (B) to an electric current and rotating the element (8), in order to cyclically immerse the entire matrices (A) in the bath (B) and progressively coat them with a metallic layer, by electrodeposition, d. at least during the execution of said step c., temporarily bringing the suspended mass (6) to the checking position and performing at least one weighing cycle by means of the device (9), in order to check the value of the thickness of the metallic layer obtained, e. when the desired value of the thickness of the metallic layer is reached, removing the matrices (A) coated with the obtained metal layer, f. removing the matrices to obtain the objects to be manufactured.

14. The method according to claim 13, characterized in that said weighing cycle provides for at least the following steps: dl . bringing the suspended mass (6) to the dripping position, d2. rotating the element (8) to cause the dripping of the at least partially coated matrices (A), d3. stopping the rotation of the element (8) and bringing the suspended mass (6) to the checking position, d4. performing weighing by means of the device (9).

15. Use of a machine (1) according to one or more of claims 1 to 12, for electroforming objects of the type of chains and necklaces, comprising a plurality of mutually coupled links or rings.