FR2708489A1 - Method and machine for automatic sorting of precious stones, or other similar objects, according to dimensional criteria. - Google Patents

Abstract

In the device or stones, placed in a suitable position and separated from each other by suitable devices (3, 4), are introduced into a transparent tube (5), driven by a vibratory movement to make them scroll between the 'emitter and receiver of at least one micrometric laser measuring device (11, 12) which communicates the results of the measurement to a programmable controller which compares them with those of a standard and which actuates a mechanical device (14) of automatic sorting of stones according to the result and which again initiates the measuring cycle.

Description

The present invention relates to a method for the automatic sorting of

  precious stones, or similar small parts, as well as the machine allowing

perform this operation.

  Before their setting on molded frames, the precious stones must indeed be sorted so that their dimensions correspond substantially to the housing intended to receive them. Traditionally, this sorting is done with a palm dial. This requires manual handling and positioning with tweezers. The precision required is more or less 0.1 mm to more or less 0.2 mm, according to the manufacturers, and this precision makes it possible to avoid having to touch up the housing and the crimping claws of the frames. In a similar field, the document FR 2,079,715 describes a process and a machine for sorting stones & lighter or other small objects of the same kind. According to this process, the stones are brought by a feed chute constituted by an inclined and vibrating tube between two sets of three rollers each intended to roll and advance the stones, these two sets of rollers being separated by a free space through which stones of insufficient length can fall. The patent does reveal a "single file" supply of aligned lighter stones, but it only separates stones that are too short and waste from stones of acceptable length thanks to an imprecise mechanical measurement of the length of the stones. In this known process, no precise dimensional measurement of the stones is made by

comparison with a standard.

  The object of the present invention is to provide a method for automating the handling, positioning, measurement of length and width, and sorting of the precious stones with respect to a reference standard and a display of the tolerance, as well as 'a

  machine for implementing said method.

  According to the present invention, this object is achieved in that the proposed method consists in carrying out the measurement (s) of the precious stones placed in a suitable position and separated from each other in a transparent tube or in a chute animated by a vibratory movement. to scroll between the transmitter and the receiver of at least one laser type measuring device which communicates the measurement results to a programmable controller which compares them to those of a standard and which actuates a mechanical sorting device automatic

stones according to the result.

  The machine for the implementation of this process is remarkable in that it ensures the following operations: - supply "in line" by vibrating bowl, - selection of the direction of the stones by suitable traps, - unit stones, - positioning of stones in a glass tube, - advance of stones by mechanical vibration of the glass tube, - length / width measurement by two transmitter / receiver assemblies of micrometric laser - sorting after measurement by programmable controller

  and initiation of a new cycle.

  Other remarkable features of the

  present invention are the subject of claims

  following. They appear from the description below

  of an embodiment of a type of machine according to the invention, given by way of nonlimiting example and illustrated by the accompanying drawings o: - Figure 1 shows an overview in

  elevation of the gemstone sorting machine.

  - Figure 2a shows a honing diagram

of the selector.

  - Figure 2b shows a honing diagram

from uniting.

  - Figure 2c shows a honing diagram

positioning.

  FIG. 3 represents a detail of the vibrator,

advance tube support.

  - Figure 4 shows a block diagram

  of the electrical and electronic brand.

  - Figure 5 shows a block diagram of the

PLC program.

  - Figure 6 shows a principle of

multiple selection.

  The method according to the present invention is read in Figure I which is a schematic representation

  of the machine intended for its implementation.

  A plate surmounting the box 1 which contains the electrical and electronic control and adjustment elements and whose front face carries the measurement and display dials as well as the buttons, switches and other control indicators, supports all the devices

forming the sorting machine.

  Thus at the entrance of the machine is placed a vibrating bowl 2 of a well known type which contains the batch of precious stones to be sorted and which has the function of scrolling these stones in a well defined position in a corridor 3. The selection of the direction of the stones is done by traps made by grooves 24 as shown in Figure 2a. The stones passing over the table 25 do not catch on the grooves while those not passing on the table 25 catch on the grooves 24 by the wire 26 or the point 27 of the breech 28

and fall back into the bowl 2.

  The "uniting" of the stones which pass through the corridor 3 is ensured by a small mechanical device 4 constituted by a knife 40 or, preferably, by a small brush 41, and controlled by an electromagnet 42. The stones are thus allowed to penetrate one after the other and individually into the measuring and

  sorting that follows (block diagram in Figure 2b).

  Thus the stone to be measured enters a small glass tube 5 of circular section in which it circulates along the lower generatrix in the direction of the arrow F, its advance being ensured according to a well-known method by the asymmetrical vibration of the tube 5 generated by a vibrating device 6 which supports the glass tube 5 and

  whose amplitude of vibration is adjustable.

  Note that gemstones other than circular in shape (oval, rectangular, pears, shuttles, etc.) are positioned lengthwise in this tube as

  this is illustrated in Figure 2c.

  FIG. 3 shows in detail the mounting of the glass tube 5 on the vibrator 6. This tube is supported by a shaped part 7, preferably made of plastic molding, itself integral with the movable frame 8 of the electro -magnet 29, the assembly being mounted on two leaf springs 9 secured by their lower end of

  the fixed armature 10 of the electromagnet 29.

  In circulation in this glass tube 5 in the direction of the arrow F, the stone passes between two micrometric laser measurement units Il and 12, one of which is intended to measure the length of the stone and the other, 12, its width along the axes respectively XX 'and YY' shown in Figure 2b. The principle, well known to those skilled in the art, of measurement with a micrometric laser consists in measuring the amount of shadow generated by the stone to be measured passing through a beam of very parallel optical rays, and will not be described in more detail here. Such a device is, for example, constituted by a micrometric cell

  Kayence LX2-12 laser followed by a Kayence LX2- amplifier

  connected to a Kayence monitor, comparator, calculator

RV2-52.

  The glass tube 5 must be very thin so that the refraction affects the measurement as little as possible. The error due to this possible refraction is corrected by

  the amplifier processing the signal from the laser receiver.

  The maximum values of the measurements are memorized

  and compared to the measurements of a standard stone.

  The tolerance of the comparator is adjustable and a

  "over the counter" signal is generated by this comparator.

  When the stone reaches the end of the glass tube 5, it passes in front of a cell 13 forming an infrared barrier which has the following effects: validation of the measurement memories by comparison, - reading of possible "over-the-counter" signals, - "good" or "bad" referrals at the exit

  tube 5 per action on a chute 14 driven by an electro-

  magnet O30 to direct the stone in the corresponding receiving tank, initialization of the measurement memories, - admission of a new stone in the tube 5

  by excitation of the unit setting solenoid 42.

  Figure 4 is an overall block diagram of the electrical and electronic part of the machine, contained in the box I which carries on its front face the control and command elements of the machine. Next to the general start switch 31 and its control light 32, there are thus two buttons 15 and 16 for adjusting the vibration intensities of the bowl 2 and of the glass tube 5 respectively according to a conventional principle. A programmable controller 17 receives the signals from the infrared passage cell 13 and from the two laser micrometer assemblies 11 and 12 as inputs and is connected at output to the totalizing counter 18 and to the "good" stone counter 19, as well as to the solenoid for unit 42 and switch 30 and a relay for validation of measurement 20. A single push button 22 "standard" allows to shift the zero of the Kayence comparator of micrometers Il and 12, after

  previous passage of a standard stone in the system.

  FIG. 5 schematically represents the program of the automaton 17. The operation of the above machine is then as follows. First put a standard stone in bowl 2 and adjust its vibration so that the stone normally goes up in the spiral. When the stone is caught in the unit setting system 4, the "start cycle" button 21 is pressed and the vibration of the tube 5 is adjusted so that the speed of the stone is between substantially 0.5 to 1 cm / sec., without start, especially in the measurement part. When this setting is correct, the stone is ironed. After the measurement and validation (passage in front of the infrared cell 13), press the "standard 'button 22. We then go back to the standard to make a check: the length displays 11 and

  width 12 should only indicate a few hundredths of a mm.

  The tolerance of the desired sorting is then adjusted by a button 23.

  The machine is then ready to operate in series. We put the lot to be sorted in the bowl 2 and, when the first stones are presented in front of the uniting system 4, we press the "start cycle" button 21. The sorting will then be done automatically for the whole lot content

in bowl 2.

  The sorting machine described above can be the subject of numerous variants, without leaving

of the scope of the present invention.

  Thus, it is well known to those skilled in the art that the selection of the direction of the stones at the outlet of the vibrating bowl 2 from the shape of selection traps can be carried out in different ways and depends on the general shape of the stones. In the same way, the "unitization" tools, interchangeable according to the shape and size of the stones to be treated, can be designed in different

  ways, interchangeable or universal.

  The glass tube 5 can be replaced by a transparent piece of suitable shape and nature allowing measurements to be made with the micrometers

laser in good conditions.

  Furthermore, it is also possible to use the machine according to the invention to make multiple selections. It is thus possible to form a batch of unsorted stones and select a series of batches

  output corresponding to certain dimensional criteria.

  A microcomputer will be able to manage all of the data and, as can be seen in FIG. 6, will command at the output of the vibrating tube 5 a series of drawers 33 in cascade sorting the stones into multiple categories,

  according to dimensional criteria for example.

  It is also possible to add to the machine a chromatic detection in order to sort the stones

  according to their color or the density of their shade.

  We can also install a "diagonal" laser micrometer which would allow the stones to be differentiated according to their shape, for example distinguishing a round stone from a

square stone.

  The machine thus described is not limited to sorting precious stones, but can be used for sorting other small similar objects, without departing from the scope of the present invention. at

Claims (3)

  1) Process for automatic sorting of precious stones, or other similar objects, according to dimensional criteria, characterized in that the stone or stones, placed in suitable position and separated from each other by suitable devices (3, 4), are introduced into a transparent tube (5), animated by a vibratory movement to make them pass between the transmitter and the receiver of at least one micrometric laser measuring device (11, 12) which communicates the results of the measurement to a programmable automaton (17) which compares them to those of a standard and which actuates a mechanical device (14) for automatic sorting of the stones according to the result and which again initializes the measurement cycle.   2) Machine for implementing the method according to claim i above, characterized in that it ensures the following successive operations: - supply "in line" by a vibrating bowl (2) selection of the direction of the stones by appropriate traps (24) - uniting of the stones - positioning of the stones in a glass tube (5), or a transparent chute - advancing the stones by mechanical vibration of the glass tube (5) - measuring the length and in width by two micrometric laser transceiver assemblies (11, 12) - sorting after measurement by programmable controller (17) and triggering of a new cycle by infrared cell (13) 3) Machine according to claim 2 ci above, characterized in that the transparent tube (5) is a tube   in thin glass of circular section.   4> Machine according to claim 2 above, characterized in that the positioning of the stones for the measurement is done in a transparent chute of suitable shape. ) Machine according to claim 2 above, characterized in that a microcomputer performs at the outlet of the glass tube (5) a multiple selection according to defined dimensional criteria.   6) Machine according to claim 2 above, characterized in that a chromatic detector further allows a selection of stones according to the color or the intensity of coloring.