IL110529A - Method and apparatus for the automatic sorting of prectous stones or similar objects, according to dimensional criteria - Google Patents

Description

METHOD AND APPARATUS FOR THE AUTOMATIC SORTING OF PRECIOUS STONES OR SIMILAR OBJECTS, ACCORDING TO DIMENSIONAL CRITERIA ONnm D"»»n n^son ΊΝ in >ϋηιοικ n>n¾ ipnni The present invention relates to a process for the automatic sorting of precious Stones, ΟΓ similar small items or articles, as well as to the machine for performing this operation.

Before being set in moulded settings, precious stones must be sorted to make sure that their dimensions correspond substantially to the collet in which they are to be placed. Traditionally this is done with micrometer-callipers with a dial. This requires a manual manipulation and positioning with tweezers. The required precision is generally more or less 0,02 mm, and this precision ensures that the collet and claws of the settings need not be altered.

In a similar field, the document FR-A-2.079.715 describes a process and a machine which permit the sorting of lighter flints or other small items of the same type. According to this process, the flints are fed to the machine through a feed chute consisting of an inclined tube which vibrates between two sets of three rollers each intended to make the flints roll and move ahead, which two sets of rollers are separated by an open space through which flints with an insufficient length can drop down. This document mentions an "in file" feeding of the aligned lighter flints, but the described device only separates the flints that are too short and rejects of flints with an acceptable length due to a not very accurate mechanical measuring of the length of the flints. With the known process no precise dimensional measuring of the stones takes place compared to a standard.

The object of the present invention is to propose a process for automating the handling, the positioning, the measuring of the length and width, and the sorting of precious stones in relation to a reference standard and a tolerance indication, as well as to a machine for performing this process.

According to the present invention, this object is achieved in that the proposed process consists of carrying out the measuring of the articles, which nay be precious stones, placed in a suitable position and separated from one another one by one in a transparent tube or in a channel animated by a vibratory movement, so that the stones will file off between the transmitter and the receiver of at least one laser type measuring device, which communicates the results of the measuring to a programmable automatic unit which compares these results with those of a reference article , which may be a standard stone , and actuates a mechanical automatic sorting device which sorts the stones according to the results .

The machine for performing this process is characterised mainly in that it ensures the following operations: - "in file" °r "one after another" feeding by a vibrating bowl , - selection of the direction of the stones by suitable traps, - putting the stones one by one, - positioning the stones in a transparent tube, - moving the stones ahead by mechanical vibration of the transparent tube, - measuring the length/width of the stones by a measuring device comprising two laser type micrometric transmitter/receiver units, - sorting after the measuring by an automatic programmable unit and starting up of a new cycle.

Other advantageous characteristics of the present invention can be noted from the following description of an embodiment of a machine according to the invention, given by way of non limitative example and illustrated in the attached drawing wherein: - figure 1 is an overall diagrammatic view, in elevation, of the machine according to the invention. - figure 2a is a partial diagrammatic view of the positioning table, - figure 2b is a diagrammatic view of the means for introducing the stones into the measuring device, - figure 2c is a partial diagrammatic view of the transparent tube, connected to the measuring device, through which the stones pass in file, - figure 3 shows a detail of the vibrator which carries the transparent tube, - figure 4 shows an overall block diagram of the electrical and electronic part of the machine, - figure 5 shows a block diagram of the programme of the automatic unit, - figure 6 shows a basic diagram of a multiple selection.

Referring first to figure 1, it will be noted that a machine according to the invention comprises a casing 1 which contains the electric and electronic control and regulating elements, and the front surface of which carries the measuring and indicating dials as well as the buttons, switches and other indicator lights, and which casing 1 supports all the devices which ensure the sorting of the stones.

At the inlet of the machine a vibrating bowl 2 of the known type is provided, which contains all the precious stones to be sorted, and which serves to make these stones pass in file over a positioning table 3. The selection of the direction of the stones is ensured by traps consisting of transverse grooves 24 provided on the positioning table 3 and shown in figure 2a. The stones which move along on the table 25 are not caught by the grooves 24, whereas those which do not move on the table 25 hook into the grooves 24 by their girdle 26 or by the point 27 of their bottom part 28 and fall into the bowl 2.

The putting one by one of the stones whicli pass over the positioning table 3 is ensured by a small mechanical device 4 formed by a knife 40 or, preferably, by a small brush 41, and controlled by an electro-magnet 42. In this way the stones are fed the one after the other and singly to the adjoining measuring and sorting device, illustrated diagrammatically in figure 2b.

The Stone to be measured is thus urged into a small glass tube 5 with circular cross-section, in which it moves along the bottom generatrix in the direction of the arrow F, its moving forward being ensured in a well-known manner by the asymmetrical vibration of the tube 5 brought about by a vibrating device 6 which supports the glass tube 5 and the vibration amplitude of which is adjustable.

Precious stones with a shape other than circular (oval, rectangular, pear-shaped, marquise, etc..) are positioned lengthways in the tube 5, as illustrated in figure 2c.

Figure 3 shows in detail the mounting means of the glass tube 5 on the vibrator 6. The tube is supported by a semi-cylindrical part 7, preferably of moulded plastic, which forms an integral part of the movable armature 8 of the electro-magnet 29, the whole being mounted on two flat springs 9 connected at their bottom end to the fixed armature 10 of the electro-magnet 29.

Whilst moving through the glass tube 5 in the direction of the arrow F, the stone passes between two laser type micrometric measuring units 11 and 12, one of which 11 serves to measure the length of the stone and the other 12 its width according to the axes XX' and YY , respectively, shown in figure 2c. The principle, well known to the expert, of measuring with a laser micrometer consists of measuring the amount of shadow generated by the stone to be measured when it passes through a pencil of very parallel optical rays, and will not be described in further detail here. Such a device consists, for example, of a KAYENCE LX2-12 micrometry laser cell followed by a KAYENCE LX2-70 amplifier connected to a KAYENCE RV2-52 monitor-comparator-calculator.

The glass tube 5 must be very thin so that the refraction will affect the measuring as little as possible. The error due to this possible refraction is corrected by the amplifier which treats the signal of the laser receiver.

The maximum values of the measurements are put into memory and compared with the measurements of a standard stone.

The tolerance of the comparator is adjustable and an "out of dimension" signal is generated by this comparator.

When the stone gets to the end of the glass tube 5, it passes in front of a cell 13 forming an infra-red barrier, which performs the following operations: - validation of the measuring memories by the comparator, - reading of possible "out of dimension" signals, - shunting to "good" or "bad" at the outlet of the tube 5 by the action on a chute 14 moved by an electro-magnet 30 so as to direct the stone into the corresponding container, - initialisation of the measuring memories, - letting a new stone into the tube 5 by excitation of the solenoid 42 of the system that puts the stones one by one.

Figure 4 is a block diagram of the whole of the electrical and electronic part of the machine contained in the casing 1 , which on its front carries the control and regulating elements of the machine. Besides the general operating switch 31 and its indicator light 32, there are two buttons 15 and 16 for regulating the vibration intensity of the bowl 2 and the glass tube 5, respectively, according to a conventional principle. A programmable automatic unit 17 receives at the input the signals of the inf ared passage cell 13 and of the two laser micrometer units 11 and 12, and is connected at the outlet to the totals counter 18 and to the "good" stones counter 19, as well as to the solenoids of the one by one putting system 42 and the shunter 30 and to a measuring validation relay 20. A "standard" push button 22 permits the shifting of the zero of the KAYENCE comparator of the micrometers 11 and 12, after first passing a standard stone through the system.

Figure 5 shows diagrammatically the programme of the automatic unit 17, and is sufficiently self-explanatory so that there is no need to comment on it.

The functioning of the above machine is as follows. First a standard or reference stone is put into the bowl 2 and its vibration is regulated so that the stone moves up normally in the spiral. When the stone is picked up by the putting system 4, the "start cycle" button 21 is pressed, and the vibration of the tube 5 is regulated so that the speed of the stone lies substantially between 0,5 to 1 cm/sec. without, however, jumping in the measuring part. When this regulation is correct, the stone is passed through again. After the measuring and its validation (passing in front of the infrared cell 13), the "standard" button 22 is pressed. The standard stone is then passed through once again to carry out a check: the indicators of the length 11 and width 12 may only indicate a few hundredths of a mm difference. By means of the button 23 the desired sorting is then regulated, which may have been pre-programmed in the indicators 11 and 12.

The machine is then ready to operate in series. The batch to be sorted is put in the bowl 2, and when the first stones come to the one by one putting system 4, the "start cycle" button 21 is pressed. The sorting then proceeds automatically for the entire batch contained in the bowl 2.

The sorting machine as described above may form the subject of numerous variations of the construction without going beyond the framework of the present invention.

Thus, it is well known to the expert that the selection of the direction of the stones at the outlet of the vibrating bowl 2 and the shape of the selection traps may be made differently and depend on the general shape of the stones.

Likewise, the tools of the one by one putting system, interchangeable according to the shape and size of the stones to be treated, may be designed in different ways, interchangeable or universal. They may on the other hand also consist of a blower positioned at the inlet of the transparent tube, which may be automatically adjustable depending on the dimensions of the stones and which prevents the moving in of a new stone before the preceding stone has gone into the measuring device.

The glass tube which is used may be replaced by a transparent part of a suitable shape and type which permits the carrying out of the measurements with the laser micrometers under good conditions.

Furthermore, it is also possible to use the machine according to the invention for carrying out multiple selections. In this case it is possible to form a batch of stones which have not been pre-sorted and to select a series of output batches which correspond to certain dimensional criteria.

A micro-computer may manage all the data and, as can be seen from figure 6, will control at the outlet of the vibrating tube 5 a series of drawers arranged in cascade 33, which sort the stones into multiple categories, e.g. according to dimensional criteria.

It is also possible to attach to the machine a chromatic detection device so as to sort the stones according to their colour or the density of their colour.

Also a "diagonal" laser micrometer may be installed, which would make it possible to differentiate the stones according to their shape, e.g. to distinguish a round stone from a square stone.

The described machine is not limited to the sorting of precious stones, but may also be used to sort other similar objects without going beyond the framework of the present invention.

Claims (16)

- 9 - 110,529/2 WHAT IS CLAIMED IS:

1. A process for the automatic sorting of articles according to dimensional criteria, comprising: feeding articles to be sorted one after the other by means of a vibrating bowl; selecting direction of movement of the articles by suitable traps provided in a positioning table, and arranging the articles separately from each other; positioning the articles in a transparent tube or channel; moving the articles ahead by mechanically vibrating the transparent tube or channel; measuring the length and/or width of the articles, and sorting the articles according to their measurements by means of a programmable automatic processing unit.

2. The process according to claim 1, wherein said arranging of the articles separately from each other is effected by means of a blower preventing an article from entering said tube or channel, before a preceding article has moved into the measuring area.

3. The process according to claim 1, further comprising selection of articles according to colour or intensity of colour thereof .

4. An automatic sorting machine for sorting articles according to dimensional criteria, comprising: - 10 - 110,529/2 means for placing articles to be sorted in a suitable position and separating said articles from each other; means for introducing the separated articles into a transparent tube or channel; means for effecting a vibratory movement to said tube or channel for causing the articles to pass between a transmitter and a receiver of at least one micrometric measuring device; a programmable automatic processing unit connected to said measuring device, and an automatic sorting device responsive to said unit for sorting the articles according to given criteria.

5. The automatic sorting machine according to claim 4, wherein said articles are precious stones or the like.

6. The automatic sorting machine according to claim 4, wherein said transparent tube or channel is made of thin glass with a circular cross-section.

7. The automatic sorting machine according to claim 4, wherein said articles are placed on a positioning table having grooves made therein for effecting the selection of the direction of movement of articles thereon.

8. The automatic sorting machine according to claim 4, wherein said articles are introduced in said tube or channel by the aid of a mechanical device. - 11 - 110,529/2

9. The automatic sorting machine according to claim 8, wherein said mechanical device is a knife or a brush controlled by an electro-magnet .

10. The automatic sorting machine according to claim 4, wherein the articles are introduced in said tube or channel with the aid of a blower positioned at the inlet of said tube or channel.

11. The automatic sorting machine according to claim 4, wherein said programmable automatic unit is a micro-computer.

12. The automatic sorting machine according to claim 4 , wherein said sorting device sorts the articles according to defined dimensional criteria.

13. The automatic sorting machine according to claim 4 , wherein said sorting device sorts the articles by means of a series of drawers arranged in cascade.

14. The automatic sorting machine according to claim 4, wherein said sorting device is a chromatic detector permitting a selection of articles according to colour or intensity of colour.

15. A process for the automatic sorting of articles according to claim 1, substantially as hereinbefore described and with reference to the accompanying drawings. - 12 - 110,529/1

16. An automatic sorting machine for sorting articles according to claim 4, substantially as hereinbefore described and with reference to the accompanying drawings. FOR THE APPLICANT WOLFF, BREGMAN AND 60LLER