MOTORIZED COORDINATE MEASURING DEVICE

• US 20090199421A1
• Filed: 02/07/2008
• Published: 08/13/2009
• Est. Priority Date: 02/07/2008
• Status: Active Grant

• Current Assignee: Homer L. Eaton
• Original Assignee: Homer L. Eaton
• Inventors: Eaton, Homer L.
• Granted Patent: US 7,587,834 B2
• Time in Patent Office: Days
• US Class Current: 33/503
• CPC Class Codes: G01B 5/0002 Arrangements for supporting, fixing or guiding the measuring instrument or the object to be measured
• CPC Class Codes: G01B 5/008 using coordinate measuring machines

Abstract

A coordinate measuring device comprises a housing rotatively supported on a base and mounting a vertical pillar along which rides a carriage engaged by a horizontally translating arm. A turret at each end of the arm houses a rotating body connected to a probe. The rotation of the base, the vertical movement of the carriage, the horizontal movement of the arm and the rotation of the probes are driven by motors in the housing. The rotation of the motors are transmitted by a cable and pulley assembly to the arm and carriage. The cable controlling the transversal movement of the arm as its opposite ends attach to the opposite extremity of the arm, and is ran respectively up and down the portion of the pillar above and below the carriage in order to maintain constant lengths and tension of the cables as the carriage moves up and down the pillar. The rotation of the probes and that of the base are coordinated to keep the probes at a constant angle in relation to the measured surface.

Claims

1. A coordinate measuring device which comprises:

a stationary base;

a housing rotatively supported on said base about a first axis;

a pillar mounted on said housing and extending along said first axis;

a carriage translatable along, and supported by said pillar;

a cross-arm slidingly engaged upon said carriage, translatable about a second axis and having opposite first and second extremities;

an electromechanical assembly in said housing, said assembly including a plurality of driving means and means for linking said driving means to said translatable carriage and sliding cross-arm; and

at least one probe mounted at said first extremity.

2. The device of claim 1, wherein said assembly comprises:

a plurality of motors, each of said motors having a driving pulley;

a plurality of direction-altering pulleys associated with said pillar and carriage; and

flexible, elongated elements engaging said pulley to translate said carriage up and down said pillar and bilaterally translate said arm about said carriage.

3. The device of claim 2, wherein assembly further comprises a motorized mechanism for rotating said housing and pillar about said first axis.

4. The device of claim 2, wherein said at least one probe comprises:

a turret secured to said first extremity;

a body within said turret, said body being rotatable about a third axis; and

a sensing element attached to said body.

5. The device of claim 4, wherein said assembly further comprises:

a supplemental motor in said housing; and

a cable and pulley mechanism for linking said motor to said body.

6. The device of claim 5, which further comprises encoding means for indicating the linear position of said carriage along said first axis, the linear position of said arm along said second axis, the angular position of said housing in relation to said base, and the orientation of said body.

7. The device of claim 4, wherein said sensing element comprises a shaft coupled at a first end to said body and a sensor mounted at an opposite end.

8. The device of claim 7, wherein said shaft projects in a direction parallel to and spaced apart from said third axis.

9. The device of claim 6, which further comprises a control unit including means for activating said motor and for positioning said probe in contact with at least one point on a workpiece surface.

10. The device of claim 7, wherein said sensor comprises an imaging apparatus;

and

said control unit further comprises means for activating said motor and positioning said imaging apparatus proximate a point on said surface.

11. The device of claim 1, which further comprises a second probe secured to the second extremity of said arm.

12. The device of claim 8 which further comprises a control unit including means for activating said motors and for positioning said probe in contact with at least one point on a workpiece surface.

13. The device of claim 12, wherein said control unit further comprises means for coordinating said orientation and said angular position.

14. The device of claim 13, wherein said means for coordinating comprise means for adjusting the angular position of said shaft in relation to said surface.

15. The device of claim 12, wherein said means for controlling further comprises means for running said probe along a path on said surface.

16. The device of claim 12, wherein said mean for controlling further comprises means for intermittently positioning said probe on a series of discrete points on said surface.

17. The device of claim 16, wherein said means for intermittently positioning comprises means for alternately and bidirectionally rotating said body over an arc of less than 180 degrees.

18. The device of claim 2, wherein said elongated element comprises cables made of synthetic plastic material.

19. The device of claim 6, wherein said encoding means comprise:

linear and circular indexers and optical detector; and

second controlling means which comprise servo systems responsive to said encoding means.

20. The device of claim 2, wherein a first of said flexible elongated elements comprises a cable secured at both ends to said carriage and engaging a first direction-altering pulley in an upper region of said pillar, a second direction-altering pulley in a lower region of said pillar and pulley driven by a first of said motors.

21. The device of claim 2, wherein a second of said flexible elongated elements comprises a cable secured at opposite ends to said first and second extremities respectively, running up and down portions of said pillar above and below said carriage, and engaging a pulley driven by a second of said motors.

22. The device of claim 5, wherein said cable and pulley mechanism comprises a close-loop cable running up and down portions of said pillar above and below said carriage.

23. A coordinate measuring device which comprises:

a stationary base;

a housing rotatively supported on said base about a first axis;

a pillar mounted on said housing and extending along said first axis;

a carriage translatable along, and supported by said pillar;

a cross-arm slidingly engaged upon said carriage, translatable about a second axis and having opposite first and second extremities;

an electromechanical assembly in said housing, said assembly including a plurality of drives and linkages linking said drives to said translatable carriage and sliding cross-arm; and

at least one probe mounted at said first extremity.