Coordinate measurement machine with improved joint

• US 7,743,524 B2
• Filed: 11/20/2007
• Issued: 06/29/2010
• Est. Priority Date: 11/20/2006
• Status: Active Grant

• Current Assignee: Hexagon Technology Center GmbH (Hexagon AB)
• Original Assignee: Hexagon Metrology AB (Hexagon AB)
• Inventors: Eaton, Homer L., Ferrari, Paul A.
• Primary Examiner(s): Johnson; Amy Cohen
• Application Number:
  US11/943,463
• Publication Number:
  US 20080127501A1
• Time in Patent Office: 952 Days
• Field of Search: 335/03, 335/56, 335/58, 335/59, 335/61, 33/1.M, 33/1.PT
• US Class Current: 33/503
• CPC Class Codes: G01B 21/047 Accessories, e.g. for positioning, for tool-setting, for measuring probes
• CPC Class Codes: G05B 2219/37193 Multicoordinate measuring system, machine, cmm
• CPC Class Codes: G05B 2219/45061 Measuring robot

Abstract

In one embodiment, a coordinate measurement apparatus includes an articulated arm having a first end and a second end with at least a first arm segment and a second arm segment therebetween. Further, the apparatus can comprise at least one ball and socket joint connecting the first arm segment to the second arm segment, with the ball and socket joint including a ball member and a socket member, and a measurement probe attached to the first end of said articulated arm.

Claims

1. A coordinate measurement apparatus comprising:

an articulated arm having a first end, a second end, at least a first arm segment and a second arm segment therebetween;

at least one ball and socket joint connecting said first arm segment to said second arm segment, said ball and socket joint comprising a ball member and a socket member, wherein the ball member comprises at least one graphical pattern and the socket member comprises at least one optical reader device configured to read said graphical pattern; and

a measurement probe attached to said first end of said articulated arm.

2. The coordinate measurement apparatus of claim 1, wherein the optical reader device comprises a camera.

3. The coordinate measurement apparatus of claim 1, wherein the ball member is maintained adjacent to the socket member using at least one magnet member.

4. The coordinate measurement apparatus of claim 1, wherein the ball member is maintained adjacent to the socket member using at least one vacuum port.

5. The coordinate measurement apparatus of claim 1, further comprising a slip ring rotatably connected to first arm segment.

6. The coordinate measurement apparatus of claim 5, further comprising at least one hardwired connection attached to the slip ring, said hardwired connection in electronic communication with the second arm segment,

wherein said hardwired connection is configured to transfer a coordinate data between said first arm segment and said first arm segment.

7. A coordinate measurement apparatus comprising:

an articulated arm having a first end, a second end, at least a first arm segment and a second arm segment therebetween;

at least one joint connecting said first arm segment to said second arm segment, said joint configured to allow said first arm segment to pivot and rotate relative to said second arm segment, wherein the joint connects the arm segments by an attractive force; and

a measurement probe attached to said first end of said articulated arm,

wherein the joint comprises a joint body rotatably coupled to the first arm segment to define a first axis of rotation of the joint and rotatably coupled to the second arm segment to define a second axis of rotation of the joint.

8. The coordinate measurement apparatus of claim 7, wherein the joint further comprises a data surface coupled to the first arm segment and a data acquisition device coupled to the second arm segment, the data acquisition device configured to acquire data from the data surface.

9. The coordinate measurement apparatus of claim 8, wherein the data surface comprises a ball portion having a graphical pattern disposed on an outer surface thereof.

10. The coordinate measurement apparatus of claim 8, wherein the data acquisition device comprises an optical camera.

11. The coordinate measurement apparatus of claim 8, wherein the joint further comprises a light element configured to illuminate the data surface.

12. A coordinate measurement apparatus comprising:

an articulated arm having a first end, a second end, at least a first arm segment and a second arm segment therebetween;

at least one joint connecting said first arm segment to said second arm segment, said joint comprising a first joint member and a second joint member;

a measurement probe attached to said first end of said articulated arm; and

a single rotational sensor between the first and second arm segments,

wherein either of said first joint member or second joint member comprises a generally convex surface and the other of either said first joint member or said second joint member comprises a rounded surface configured to generally mate with said convex surface of said first joint member so that said first arm segment is configured to pivot and rotate relative to said second arm segment, said pivots and rotations being measurable by the single rotational sensor.

13. The coordinate measurement apparatus of claim 12, wherein the convex surface is maintained adjacent to the rounded surface using at least one magnet member.

14. A method of operating a coordinate measurement apparatus to acquire coordinate data regarding a target surface comprising the steps of:

moving a first arm segment relative to a second arm segment using a first joint, said first joint configured to permit said first arm segment to pivot and rotate relative to said second arm segment;

acquiring position data of the pivotal and rotational position of the first arm segment relative to the second arm segment from a data surface of the first joint; and

moving a probe member connected to said first arm segment relative to said target surface.

15. The method of claim 14, wherein acquiring position data further comprises optically capturing a graphical pattern on the data surface, the graphical pattern adapted to provide position data regarding pivot and rotation amounts of the first arm segment relative to the second arm segment.

16. A coordinate measurement apparatus comprising:

an articulated arm having a first end, a second end, at least a first arm segment and a second arm segment therebetween;

at least one joint connecting said first arm segment to said second arm segment, said joint comprising a first joint member and a second joint member; and

a measurement probe attached to said first end of said articulated arm,

wherein said joint is capable of movement in two or more degrees of freedom, and measurement of both degrees of freedom is performed by measuring a single coded surface.

17. The coordinate measurement apparatus of claim 16, wherein said coded surface is spherical.

18. The coordinate measurement apparatus of claim 16, further comprising a camera and wherein measurement is performed by use of the camera.

19. The coordinate measurement apparatus of claim 16, further comprising a spherical encoder and wherein measurement is performed by the spherical encoder.

20. A coordinate measurement apparatus comprising:

an articulated arm having a first end, a second end, at least a first arm segment and a second arm segment therebetween;

at least one joint connecting said first arm segment to said second arm segment, said joint configured to allow said first arm segment to pivot and rotate relative to said second arm segment, wherein the joint connects the arm segments by an attractive force; and

a measurement probe attached to said first end of said articulated arm having at least one degree of free movement relative to both the first and second arm segments.

21. The coordinate measurement apparatus of claim 20, wherein the joint comprises a ball and socket joint.