WO2016079564A1

WO2016079564A1 - Method for automatically setting a stone in a workpiece

Info

Publication number: WO2016079564A1
Application number: PCT/IB2014/066117
Authority: WO
Inventors: Chris KEERSMAEKERS
Original assignee: Daems Giovanni Bvba
Priority date: 2014-11-18
Filing date: 2014-11-18
Publication date: 2016-05-26

Abstract

This invention relates to a method for automatically setting a stone (1), such as a precious stone, a semi-precious stone or a non-precious stone in a workpiece (3), comprising successive steps: a. picking up the stone (1) using a handling device; b. putting the stone (1) in a hole (2) of the workpiece (3), which is flanked by prongs (4), by means of the handling device and applying a certain force; c. bending the prongs (4) using a pusher (5), bringing the pusher (5) over a certain distance Zmax from a reference point Z0 above the stone (1) towards the stone (1); this method further comprising measuring at least one parameter of the position of the stone (1) in the hole (2) and adjusting the distance Zmax over which the pusher (5) is brought toward the stone (1) in step c in function of the measured parameter.

Description

METHOD FOR AUTOMATICALLY SETTING A STONE IN A

WORKPIECE

The present invention relates to a method for automatically setting a stone, such as a precious stone, a semi-precious stone or a non-precious stone in a workpiece, such as a piece of jewellery or a timepiece, comprising successive steps:

a. picking up the stone using a handling device;

b. putting the stone in a hole of the workpiece, which is flanked by prongs, by means of the handling device and applying a certain force;

c. bending the prongs using a pusher, bringing the pusher over a certain distance

Z_max from a reference point above the stone towards the stone.

The method according to the invention is more specifically suitable for round-cut stones and more specifically round-cut diamonds. It is however also suitable for setting any other stones and/or stones of different cut in workpieces.

The setting of a stone, such as a precious stone, semi-precious stone or non-precious stone, in a workpiece, such as a piece of jewellery, such as a ring, a bracelet, a pendant for a chain, or a timepiece, is generally carried out by hand. The precision and the treatment of both the stone and the workpiece is namely strongly determinant for the final look of this stone in a particular workpiece.

After setting a stone in a workpiece, the prongs partially clasp the stone. It is desired that the prongs then closely lie along the stone. Prongs are preferably rounded, so that for example with a piece of jewellery, comprising stones which have been set, a person will less readily get caught on, for example, clothing. When the distance over which the stone is put in the hole deviates, the distance over which the pusher is brought to the stone for bending the prongs, has therefore to be adapted accordingly.

Some machines have already been developed for setting stones automatically, using handling devices. Such handling devices are e.g. known from BE 1 019 01 1 A3, US 5,271,132 A, WO 2013/135781 Al, WO 2009/0891 1 Al and from PCT/IB2014/062828 from current applicant. In order to bend the prongs in a suitable way, in most known machines for setting stones automatically, only stones with dimensions within certain tolerances are set. The pusher will then always be brought over a same predetermined distance from a reference point towards the respective stone to be set. Even then, however, at setting such stones with known dimensions within certain tolerances in holes with known dimensions within certain tolerances, the height over which the stone comes out of the hole after putting it in the hole will deviate, such that with stones which are put lower than estimated, the prongs will not be bent enough and with stones which are put higher than estimated, the prongs can get damaged or the stones can get damaged or the pusher can get damaged.

With the few existing machines with which stones with different dimensions are set automatically, this problem only gets worse. Not only the dimensions of the stones will deviate, but also the dimensions of the prongs. Different pushers are used for setting different stones, or different pushers are used per prong, etc. Chances only get higher that either the prongs are not bent enough, either machine parts and/or the stones to be set an/or the prongs to be bent get damaged.

The object of the invention is to provide a method for setting stones, with which prongs can be bent in a more reliable and accurate way.

This object is achieved by providing a method for automatically setting a stone, such as a precious stone, a semi-precious stone or a non-precious stone in a workpiece, comprising successive steps:

a. picking up the stone using a handling device;

c. bending the prongs using a pusher, bringing the pusher over a certain distance Zmax from a reference point above the stone towards the stone;

wherein this method further comprises measuring at least one parameter of the position of the stone in the hole and comprises adjusting the distance Z_max over which the pusher is brought towards the stone in step c in function of the measured parameter.

A more specific method according to the invention further comprises providing the workpiece with a hole flanked by prongs, prior to the putting of the stone in this hole according to step b.

With the existing machines for automatically setting stones in a workpiece, the pusher was always pushed towards the stone over a predetermined distance, which was theoretically determined, based on an estimated position of the stone in the hole, which was based on the depth of the hole and the height of the stone. The depth of the hole was mostly the desired depth. Holes were drilled in the workpiece over a certain depth, such that the actual depths of the holes drilled in this way could deviate from each other. Stones were selected within certain tolerances, wherein the heights of these stones also deviated within the set tolerances.

According to the invention, now at least one parameter of the actual position of the stone in the hole is measured, and the distance over which the pusher is brought towards the stone is adjusted in function of this measured parameter. Several parameters and several adjustments are suitable for obtaining more reliable and more accurate bending of the prongs.

Both the actual dimensions of the hole and the actual dimensions of the stone have an influence on the position of the stone in the hole after putting the stone in the hole and are therefore suitable as said parameters. Knowing any of them and adjusting the distance over which the pusher is brought towards the stone in function thereof already improves the bending of the prongs.

Even more accurate results will be obtained when parameters of the position of the stone with respect to the hole are measured after putting the stone in the hole. In a first specific embodiment, the depth of the hole is measured as a said parameter. When the hole is provided by drilling, then more specifically, art drilling the drilling depth can e.g. be recorded in order to measure the depth of the hole.

In a second specific embodiment, the height of the stone is measured as a said parameter.

In a third specific embodiment, at putting the stone in the hole according to step b, the distance Z_tabi_e over which the stone is put in the hole is recorded as a said parameter.

When the handling device comprises a main body, which in step b is positioned at a certain distance from the workpiece; a vacuum body for engaging the stone by suction, which is mounted moveable with respect to the main body; damping means for damping movement of the vacuum body with respect to the main body; and means for determining when the damping means apply a predetermined damping force, corresponding to the force for putting the stone in the hole during step b; then it is possible, when the predetermined damping force is reached, to record the distance over which the vacuum body has moved with respect to the main body as a measure for the distance Z_tabi_e over which the stone is put in the hole.

Such handling device is preferably a handling device as described in PCT/IB2014/062828 from current applicant.

The distance Z_tabi_e over which the stone is put in the hole is then preferably measured from the reference point.

When the stone comprises a table, then after putting the stone in the hole, Z_tabi_e is preferably the distance between the reference point and the table of the stone. The table of a stone having a table, is that surface which, after the stone has been set in the workpiece, is directed upwards and is normally virtually parallel to the surface of the workpiece in which the stone has been fitted.

In a specially preferred embodiment of a method according to this invention, the depth of the hole is measured and from the measured depth of the hole and the height of the stone, a theoretical distance Z_tabi_e,theor is calculated over which the stone would theoretically be put in the hole, calculated from the reference point, and a theoretical distance Z_maX;theor from the reference point is calculated over which the pusher should be brought towards the stone in step c, the difference Z_corr between the theoretical distance Z_tabi_e,theor over which the stone would theoretically be put in the hole and the measured distance Z_tabi_e over which the stone is put in the hole, measured form the reference point, is calculated and the distance Z_max over which the pusher is brought toward the stone in step c is calculated from

r chosen between 0.75 and 1, preferably between 0.8 and 1.

The mentioned height of the stone can here be taken as the target height of a batch of stones, which all have a height within certain tolerances from this target height. This mentioned height can also be the actual measured height of this stone.

This r can be 1 or can e.g. be a chosen function, e.g. chosen to limit the adjustment of 7

In a most preferred embodiment, r is chosen to be about 0.85. This invention will now be commented on in greater depth based on the subsequent detailed description of a preferred method according to this invention. The purpose of this description is exclusively to give illustrative examples and to indicate further advantages and special features of this invention, and may thus in no way be interpreted as a limitation of the scope of application of the invention or of the patent rights requested in the claims.

This detailed description will use reference numerals to refer to the appended drawing which schematically illustrates how a stone can be set in a hole. In this detailed description a specific method is described for putting a stone (1), having a table (6), a crown, a girdle, a pavilion and a culet (7) in a workpiece (3). The table (6), is that surface which, after the stone (1) has been set in the workpiece (3), is directed upwards and is normally virtually parallel to the surface of the workpiece (3) in which the stone (1) has been fitted. The culet (7) of the stone (1) is the end of the stone (1) opposite the table (6), which end in the setting process, is fitted in the hole (2) in the workpiece (3). The top edge of the stone (1) just below the table (6) is crown and the bottom edge of the stone (1) just above the culet (7) is the pavilion. The girdle is the boundary between the crown and the pavilion of the stone (1)· For a man skilled in the art, it will be clear how the described method can suitably be adapted for setting any other stones and/or stones of different cut in workpieces.

In the further described method for setting a stone (1) in a workpiece (3), a stone (1) from a batch of stones with dimensions (such as the height, the crown angle (a) and the radius R_stone at the height of the girdle) within certain tolerances is chosen for setting.

A suitable pusher (5) is chosen for this batch, of which the circle of material which will come closest to the stone (1) has a suitable diameter Rtarget- It is calculated how far (Z_{max t}heor) the pusher (5) can maximally be brought down with respect to the reference line Zo_; taking the highest expected stone (1) of the batch into account.

The workpiece (3) is in a known way provided with a hole (2), with dimensions suitably corresponding to the dimensions of the stones from the batch and with prongs (4) flanking the hole (2). At drilling of the hole (2), the drilling depth is recorded in order to derive the depth of the hole (2) as actually drilled.

From this drilling depth, the expected height of the table (6) of the stone (1) to be set in this hole (2), after setting thereof is calculated (Z_tabie,theor)- Then both the theoretical distance Z_maX;theor over which the pusher (5) can maximally be brought towards the stone (1) and the theoretical distance Z_tabie,theor of the table (6) of the stone (1) with respect to the reference line Z₀, after setting thereof, are transferred to a setting device. This setting device comprises a handling device, which comprises a main body and a vacuum body for engaging the stone by suction, which is mounted moveable with respect to the main body. Damping means are provided in this handling device, for damping movement of the vacuum body with respect to the main body. The handling device further comprises means for determining when the damping means apply a predetermined damping force.

In this setting device, a stone (1) is in a known way picked from the batch using the handling device, by engaging it to the vacuum body by suction.

The main body of the handling device is then positioned at a certain distance above the hole (2). The vacuum body is then moved with respect to the main body for putting the stone (1) in the hole (2). The vacuum body is therefore moved towards the workpiece (3), until it is determined that the damping means apply the predetermined damping force. Then, the distance over which the vacuum body has been moved with respect to reference line R₀ in figure 1 is recorded. From this measure, the distance Z_tabi_e between the reference line Ro and the table (6) of the stone (1) is derived.

The stone (1) is released by the handling device and the handling device is moved away.

The difference Ζ_∞ΓΓ between the theoretical distance Z_tabie,theor over which the stone (1) would theoretically be put in the hole (2) and the measured distance Z_tabie over which the stone (1) is actually put in the hole (2) is calculated. Then, the distance over which the pusher (5) is to be brought towards the stone is calculated as

Thereafter, the pusher (5) is positioned above the stone (1) and is brought towards the stone (1) up to Z_max.

Claims

C L A I M S

Method for automatically setting a stone (1), such as a precious stone, a semiprecious stone or a non-precious stone in a workpiece (3), comprising successive steps:

a. picking up the stone (1) using a handling device;

b. putting the stone (1) in a hole (2) of the workpiece (3), which is flanked by prongs (4), by means of the handling device and applying a certain force;

c. bending the prongs (4) using a pusher (5), bringing the pusher (5) over a certain distance Z_max from a reference point Zo above the stone (2) towards the stone (2);

characterized in that this method comprises measuring at least one parameter of the position of the stone (1) in the hole (2) and comprises adjusting the distance Z_max over which the pusher (5) is brought towards the stone (1) in step c in function of the measured parameter.

Method according to claim 1 , characterised in that the method comprises providing the workpiece (3) with a hole (2) flanked by prongs (4), prior to the putting of the stone (1 ) in this hole

(2) according to step b.

3. Method according to any of the preceding steps, characterised in that the depth of the hole (2) is measured as a said parameter.

4. Method according to claim 2 and 3, characterised in that the hole (2) is provided by drilling and that at drilling the drilling depth is recorded in order to measure the depth of the hole (2).

5. Method according to any of the preceding claims, characterised that the height of the stone (1) is measured as a said parameter. Method according to any of the preceding claims, characterized in that at putting the stone (1) in the hole (2) according to step b, the distance Z_tabie over which the stone (1) is put in the hole (2) is recorded as a said parameter.

Method according to claim 6, characterised in that the handling device comprises a main body, which in step b is positioned at a certain distance from the workpiece (3); a vacuum body for engaging the stone (1) by suction, which is mounted moveable with respect to the main body; damping means for damping movement of the vacuum body with respect to the main body; and means for determining when the damping means apply a predetermined damping force, corresponding to the force for putting the stone (1) in the hole (2) during step b; and that when the predetermined damping force is reached, the distance over which the vacuum body has moved with respect to the main body is recorded as a measure for the distance Z_tabi_e over which the stone (1) is put in the hole (2).

Method according to claim 6 or 7, characterised in that the distance Z_tabi_e over which the stone (1) is put in the hole (2) is measured from the reference point.

Method according to claim 8, characterised in that the stone (1) comprises a table (6) and that after putting the stone (1) in the hole (2), Z_tabi_e is the distance between the reference point Z₀ and the table (6) of the stone (1).

Method according to claims 3 or 4 and claim 8 or 9, characterised in that from the measured depth of the hole (2) and the height of the stone (1), a theoretical distance Z_tabi_e,theor is calculated over which the stone (1) would theoretically be put in the hole (2), calculated from the reference point Z₀, and a theoretical distance Z_{max t}heor from the reference point Zo is calculated over which the pusher (5) should be brought towards the stone (1) in step c, that the difference Z_corr between the theoretical distance Z_tabi_e,theor over which the stone (1) would theoretically be put in the hole (2) and the measured distance Z_tabi_e over which the stone (1) is put in the hole (2) is calculated and that the distance Z_max over which the pusher (5) is brought toward the stone (1) in step c is calculated from

r chosen between about 0.75 and about 1.

Method according to claim 5 and claim 10, characterised in that as the height of the stone (1) for calculating the theoretical distance Z_tabie,theor over which the stone (1) would theoretically be put in the hole (2), calculated from the reference point Z₀, the measured height of the stone (1) is taken.

Method according to claim 10 or 1 1, characterised in that r is chosen to be about 0.85.