Contact digitizer, particularly for dental applications

• US 5,131,844 A
• Filed: 04/08/1991
• Issued: 07/21/1992
• Est. Priority Date: 04/08/1991
• Status: Expired due to Term

• Current Assignee: Foster-Miller Incorporated (Thermo Fisher Scientific Incorporated)
• Original Assignee: Foster-Miller Incorporated (Thermo Fisher Scientific Incorporated)
• Inventors: Lane, Alan J., Captain, Khushroo M., Nappi, Bruce, Marinaccio, Paul J.
• Primary Examiner(s): WEHNER, CARY ELLEN
• Application Number:
  US07/682,001
• Time in Patent Office: 470 Days
• Field of Search: 433/72, 433/75, 433/76, 409/92, 409/126, 409/98, 409/99, 409/103, 409/114, 409/121, 409/124, 364/474.03, 364/474.29, 33/503, 33/504, 33/513, 33/514, 128/776
• US Class Current: 433/72
• CPC Class Codes: A61C 13/0004 Computer-assisted sizing or machining of dental prostheses
• CPC Class Codes: A61C 19/04 Measuring instruments specially adapted for dentistry A61C5/44 takes precedence; testing vitality of teeth A61B5/0534; radiation diagnosis specially adapted for dentistry A61B6/51
• CPC Class Codes: A61C 7/002 Orthodontic computer assisted systems
• CPC Class Codes: A61C 7/146 Positioning or placement of brackets; Tools therefor
• CPC Class Codes: A61C 9/008 Mechanical means or methods, e.g. a contact probe moving over the teeth

Abstract

A dental surface tracer includes a probe with a tip that can be moved to trace a given dental surface, including a mounting device for mounting the tracer to a stable reference location and defining a base plane; a first plurality of links which are substantially coplanar and define a plane of movement; the links being pivotably attached to the mounting device so that the plane of movement makes a variable angle with the base plane; a distal one of the first plurality of links being movable in two dimensions within the plane of movement; circuitry for generating electrical signals representative of movements of the probe tip, as a function exclusively of movements of the first plurality of links; a dental handpiece supporting the probe; and a second plurality of links which hold the handpiece and are attached to the first plurality of links; the second plurality of links holding the probe tip at all times at a fixed location in the plane of movement with respect to the distal link of the first plurality of links; and permitting the handpiece to move about three axes without moving the probe tip from the fixed location. The entire tracer exclusive of the handpiece is sized to be accommodated within the human mouth.

Claims

1. A probe system comprising:

a probe;

a linking arrangement supporting said probe and having a plurality of joints providing at least 6 degrees of freedom for the probe;

a device for attaching said linking arrangement to a stable reference location; and

a sensing system which measures all movements of said probe with respect to said reference location;

wherein said linking arrangement comprises a first plurality of joints providing three degrees of freedom for said probe, movement of those joints being sensed by said sensing system; and

wherein said linking arrangement comprises a second plurality of joints providing said probe with three degrees of freedom independently of said first plurality, movement of said second plurality of joints not being sensed.

2. A system as in claim 1, wherein said attaching device is capable of attaching the linking arrangement to a work bench.

3. A system as in claim 1, wherein said probe system is for scanning dental surfaces;

said attaching device is capable of attaching the linking arrangement to a reference location on a given jaw; and

said probe is movable to completely scan a predetermined dental surface on said given jaw.

4. A system as in claim 3, further comprising an adhesive which adheres said attaching device to said reference location.

5. A system as in claim 3, further comprising a handpiece which is firmly attached to said probe.

6. A system as in claim 5, wherein said probe has a curved shank extending from said handpiece and a tip at a distal end of said shank.

7. A system as in claim 6, wherein said curved shank is shaped so as to permit convenient access to all portions of such dental surface.

8. A system as in claim 7, wherein said distal end of said curved shank defines an angle with respect to said handpiece, which angle is selected to permit the distal end of the shank to be perpendicular to the plane of a given jaw while the handpiece extends away from the jaw, remaining clear of the teeth of the jaw.

9. A system as in claim 7, wherein said linking arrangement comprises at least first through sixth links which define at least first through fifth joints in that order, and a sixth joint is defined between said sixth link and the combination of said probe and handpiece.

10. A system as in claim 9, wherein said second, third and fourth links are substantially coplanar.

11. A system as in claim 10, wherein said fourth, fifth, and sixth joints form gimbal means permitting movement of said handpiece while said probe tip and said first through third joints remain in the same position.

12. A system as in claim 11, wherein said gimbal means provides three degrees of freedom for said handpiece and permits rotation of said probe tip while said probe tip remains at the same location with respect to said first through third joints.

13. A system as in claim 12, wherein said sixth joint is a journal which permits the probe to rotate about its longitudinal axis with respect to said sixth link.

14. A system as in claim 11, wherein said fourth and fifth joints are swivel joints each having an axis of rotation.

15. A system as in claim 14, wherein said probe tip remains at all times at the common axis of rotation of said fourth, fifth and sixth joints.

16. A system as in claim 15, wherein said sensing system comprises at least one Hall sensor and at least one magnet associated with said linking arrangement.

17. A system as in claim 15, wherein said sensing means comprises a Hall affect sensor system associated with said first, second and third joints.

18. A system as in claim 17, comprising first, second and third Hall sensors associated respectively with said first, second and third joints, said first Hall sensor sensing relative movement of said first and second links, said second Hall sensor sensing relative movement of said second and third links, and said third Hall sensor sensing relative movement of said third and fourth links.

19. A system as in claim 18, further comprising an elongated magnet on said third link and operatively associated with both said second and third Hall sensors, which are respectively on said second and fourth links.

20. A system as in claim 19, further comprising a horseshoe magnet operatively associated with said first Hall sensor.

21. A system as in claim 18, further comprising linearizing means for receiving output signals from said Hall sensors and improving the linearity thereof.

22. A system as in claim 3, wherein said sensing system has means for generating electrical signals representative of said movements of said probe.

23. A dental surface tracer including a dental probe having six degrees of freedom, comprising:

a mounting device which is capable of being mounted to a reference location with respect to a given jaw and defining a base plane;

a first link which is integral with said mounting device;

substantially coplanar second, third and fourth links defining a plane of movement;

said second link being pivotally mounted to said first link so that said plane of movement is movable above and below said base plane;

first means for generating electrical signals representative of such movement;

said second, third and fourth links being jointed together to have predetermined ranges of relative angular motion so that a distal end of said fourth link is movable over a predetermined area in said plane of movement;

whereby said distal end has three degrees of freedom;

second means for generating electrical signals representative of such movement;

a probe; and

gimbal means supporting said probe and attached to said distal end of said fourth link, for permitting said probe to move with three degrees of freedom without any movement of said first through fourth links;

whereby said probe can move with respect to said reference location with six degrees of freedom.

24. A tracer as in claim 23, wherein all of said links and gimbal means are sized for being accommodated within the human mouth.

25. A tracer as in claim 24, wherein said second, third and fourth links are jointed to provide greater than 90°

of relative angular motion between each pair of adjacent links.

26. A tracer as in claim 25, wherein substantially 100°

of relative angular motion is provided.

27. A tracer as in claim 23, wherein said probe has a tip for tracing a desired dental surface on said jaw, and said first and second means generate electrical signals representative of movement of said probe tip on said dental surface.

28. A tracer as in claim 27, wherein said gimbal means permit rotation of said probe tip within said plane of movement without any movement of said first through fourth links.

29. A tracer as in claim 28, wherein said probe tip remains at all times at the same location with respect to said first through fourth links.

30. A dental surface tracer including a probe with a tip that can be moved to trace a given dental surface, comprising:

a mounting device for mounting said tracer to a stable reference location and defining a base plane;

a first plurality of links which are substantially coplanar and define a plane of movement;

said links being pivotably attached to said mounting device so that said plane of movement makes a variable angle with said base plane;

a distal one of said first plurality of links being movable in two dimensions within said plane of movement;

means for generating electrical signals representative of movements of said probe tip, as a function exclusively of movements of said first plurality of links;

a dental handpiece supporting said probe; and

a second plurality of links which hold the handpiece and are attached to said first plurality of links;

said second plurality of links holding said probe tip at all times at a fixed location in said plane of movement with respect to said distal link of said first plurality of links; and

permitting said handpiece to move about three axes without moving said probe tip from said fixed location.

31. A tracer as in claim 30, wherein said entire tracer exclusive of said handpiece is sized to be accommodated within the human mouth.