AUTOMATIC GEMSTONE ORIENTATION

• US 20140119613A1
• Filed: 04/20/2012
• Published: 05/01/2014
• Est. Priority Date: 04/26/2011
• Status: Active Grant

• Current Assignee: Gemfair Ltd.
• Original Assignee: De Beers Centenary AG (Anglo American PLC)
• Inventors: D'Gama, Siobhan, Powell, Graham Ralph, Willis, Maxwell Ralph, Davies, Nicholas Matthew
• Granted Patent: US 9,796,536 B2
• Time in Patent Office: Days
• US Class Current: 382/109
• CPC Class Codes: B65G 47/244 by turning them about an axis substantially perpendicular to the conveying plane
• CPC Class Codes: G01N 21/87 Investigating jewels G01N21/88 takes precedence
• CPC Class Codes: G01N 33/381 precious stones; pearls
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80

Abstract

A method and apparatus for orientating discrete objects, such as gemstones, is described. The method comprises providing the objects on a travelling path; providing a pair of opposed walls (38) extending generally along the direction of the path; and generating relative oscillatory movement (14) between the pair of walls (38) and the travelling path (in a direction generally transverse to the direction of the path), so that the pair of walls (38) imparts lateral force to the objects to thereby urge them into their most stable orientation as they progress along the path. A device for checking the orientation of the discrete objects is also described.

Claims

1. An apparatus for orientating discrete objects, said apparatus comprising:

a movable surface providing a travelling path for said objects;

a pair of opposed walls extending generally along the direction of the path; and

an oscillator arranged to generate relative oscillatory movement between said pair of walls and said movable surface, in a direction generally transverse to the direction of the path, so that, in use, said pair of walls imparts lateral force to the objects to thereby urge them into their most stable orientation as they progress along the path.

2. The apparatus according to claim 1 further comprising a device for checking the orientation of the objects after they emerge from between the pair of walls.

3. The apparatus according to claim 1 wherein the movable surface is translatable or rotatable.

4. The apparatus according to claim 3 wherein the movable surface is a rotatable disc.

5. The apparatus according to claim 4 wherein the oscillator is arranged such that a central portion of the pair of walls oscillates along a radial direction of the rotatable disc.

6. The apparatus according to claim 1 wherein the pair of walls are interconnected.

7. The apparatus according to claim 6 wherein the pair of walls are part-toroidal.

8. The apparatus according to claim 1 wherein the oscillator is configured to provide a range of oscillation rates and/or distances or a variable oscillation rate and/or distance.

9. The apparatus according to claim 1 further comprising a feeder for providing the objects on the movable surface.

10. The apparatus according to claim 9 wherein the feeder comprises a hopper configured to space out the objects along the travelling path so that the risk of the objects coming into contact with each other as they are agitated by the oscillator is minimised.

11. The apparatus according to claim 1 further comprising a handler configured for transporting the objects from the movable surface after they have passed between the pair of walls at least once.

12. The apparatus according to claim 11 wherein the handler comprises a vacuum wand.

13. The apparatus according to claim 11 wherein the handler is configured to only transport those objects identified as being correctly orientated.

14. The apparatus according to claim 11 wherein the handler is configured to transport the objects to an appropriate receptacle or collection point.

16. An apparatus for screening for artificial gemstones, said apparatus comprising:

the apparatus for orientating discrete objects according to claim 1;

a feeder for providing gemstones on the movable surface;

a test device for determining whether the gemstones are artificial; and

a handler for transporting the gemstones to the test device and subsequently transporting the gemstones to an appropriate receptacle or collection point.

17. The apparatus according to claim 16 further comprising a device for checking the orientation of the gemstones.

15. A device for checking the orientation of discrete objects, said device comprising:

an image capture module arranged to obtain an image of the object; and

a processor configured for;

converting the image into a binary silhouette;

plotting the number of pixels representing the object in each row against row number,

fitting an expected curve to the plotted data,

calculating the error between the fitted curve and the plotted data; and

determining whether the error is within a pre-determined threshold denoting that the object is orientated as desired.

18. (canceled)

19. A method of orientating discrete objects comprising:

providing said objects on a travelling path;

providing a pair of opposed walls extending generally along the direction of the path; and

generating relative oscillatory movement between said pair of walls and said travelling path, in a direction generally transverse to the direction of the path, so that said pair of walls imparts lateral force to the objects to thereby urge them into their most stable orientation as they progress along the path.

20. The method according to claim 19 wherein the objects are urged into an orientation in which the objects have their lowest potential energy.

21. The method according to claim 19 wherein the objects are gemstones and the method comprises orientating the gemstones table-down.

22. The method according to claim 21 wherein each gemstone lies in the range of from approximately 0.01 to approximately 0.20 carats.

23. The method according to any one of claim 19 wherein the travelling path is circular.

24. The method according to claim 23 wherein the relative oscillatory movement is such that a central portion of the pair of walls oscillates along a radial direction of the travelling path.

25. The method according to claim 24 wherein the pair of walls are semi-circular.

26. The method according to claim 19 further comprising the step of checking the orientation of each of the objects after the objects have emerged from between the pair of walls.

27. The method according to claim 26 wherein the step of checking the orientation of each object comprises:

obtaining an image of the object;

converting the image into a binary silhouette;

plotting the number of pixels representing the object in each row of the silhouette against row number;

fitting an expected curve to the plotted data;

calculating the error between the fitted curve and the plotted data; and

determining whether the error is within a pre-determined threshold denoting that the object is orientated as desired.

28. The method according to claim 27 wherein the expected curve comprises a straight line.

29. The method according to claim 26 further comprising the step of sending the object along the travelling path for a second or subsequent time, if the object is determined not to be orientated as desired.

30. The method according to claim 26 further comprising the step of adjusting the oscillation frequency based on information obtained during the step of checking the orientation of each object.

31. The method according to claim 26 further comprising the step of transporting the objects that are orientated as desired to a test, measurement or further processing station.

32. The method according to claim 31 further comprising performing a test, measurement or processing procedure.

33. The method according to claim 32 wherein the procedure may comprise determining whether the object is synthetic or natural.

34. The method according to claim 32 or further comprising dispensing the object into an appropriate receptacle depending on the outcome of the procedure.