Portable coordinate measurement machine with improved counter balance

• US 20030172536A1
• Filed: 02/13/2003
• Published: 09/18/2003
• Est. Priority Date: 02/14/2002
• Status: Active Grant

• Current Assignee: Faro Technologies Incorporated
• Original Assignee: Faro Technologies Incorporated
• Inventors: Hasloecher, Kenneth J., Raab, Simon, Barber, Marc, Sajedi, Seyed Ali
• Granted Patent: US 6,904,691 B2
• Time in Patent Office: Days
• US Class Current: 33/503
• CPC Class Codes: B23Q 35/04 using a feeler or the like travelling along the outline of the pattern, model or drawing; Feelers, patterns, or models therefor
• CPC Class Codes: B25J 17/025 mounted in series
• CPC Class Codes: B25J 19/0016 using springs
• CPC Class Codes: B25J 19/0091 Shock absorbers in general F16F
• CPC Class Codes: B25J 9/0012 making use of synthetic construction materials, e.g. plastics, composites
• CPC Class Codes: B25J 9/023 Cartesian coordinate type
• CPC Class Codes: B25J 9/06 characterised by multi-articulated arms
• CPC Class Codes: B25J 9/1602 characterised by the control system, structure, architecture
• CPC Class Codes: G01B 11/005 coordinate measuring machines
• CPC Class Codes: G01B 11/03 by measuring coordinates of points
• CPC Class Codes: G01B 11/25 by projecting a pattern, e.g. one or more lines, moiré fringes on the object G01B11/255 takes precedence ; image analysis for depth or shape recovery G06T7/50
• CPC Class Codes: G01B 21/045 Correction of measurements G01B9/02055 takes precedence
• CPC Class Codes: G01B 5/004 for measuring coordinates of points
• CPC Class Codes: G01B 5/008 using coordinate measuring machines
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light
• CPC Class Codes: Y10S 33/01 Magnetic

Abstract

A portable coordinate measurement machine comprises an articulated arm having jointed arm segments. The articulated arm includes an integrated, internal counterbalance in one of its hinge joints. This counter-balance utilizes a coil spring having relatively wide end rings and narrower internal rings machined from a metal cylinder. The spring further includes at least two posts for locking into the hinge structure of the arm as well as a spring adjustment mechanism.

Claims

1. A portable coordinate measurement machine (CMM) for measuring the position of an object in a selected volume, comprising:

a manually positionable articulated arm having opposed first and second ends, said arm including a plurality of jointed arm segments, each arm segment including at least one position transducer for producing a position signal, two of said jointed arm segments having a hinge joint therebetween;

a spring counter-balance coaxially mounted around said hinge joint, wherein said spring counter-balance is an integral and internally mounted component of said articulated arm;

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

an electronic circuit which receives the position signals from the transducers and provides a digital coordinate corresponding to the position of the probe in a selected volume.

2. The CMM of claim 1 wherein:

said spring is machined from a metal cylinder.

3. The CMM of claim 1 wherein:

said spring includes a pair of opposed wider end rings and narrower internal rings.

4. The CMM of claim 3 wherein said hinge joint comprises a substantially cylindrical component having a recessed interior portion defined by a pair of shoulders and a smaller diameter cylindrical surface between said shoulders and wherein:

said spring is positioned on said recessed portion and said end rings are captured between said shoulders.

5. The CMM of claim 3 including:

at least one locking post on one of said end rings and at least one locking post on the other of said end rings, said posts mating with complimentary locking grooves in said two arm segments.

6. The CMM of claim 5 including:

at least two locking posts on one of said end rings.

7. The CMM of claim 5 including:

an adjustment device in contact with said at least one post for urging said post circumferentially and thereby adjusting the wind-up of said spring.

8. The CMM of claim 7 wherein said adjustment device comprises a screw.

9. The CMM of claim 2 wherein:

said spring includes a pair of opposed wider end rings and narrower internal rings.

10. The CMM of claim 9 wherein said hinge joint comprises a substantially cylindrical component having a recessed interior portion defined by a pair of shoulders and a smaller diameter cylindrical surface between said shoulders and wherein:

said spring is positioned on said recessed portion and said end rings are captured between said shoulders.

11. The CMM of claim 9 including:

at least one locking post on one of said end rings and at least one locking post on the other of said end rings, said posts mating with complimentary locking grooves in said two arm segments.

12. The CMM of claim 11 including:

at least two locking posts on one of said end rings.

13. The CMM of claim 1 wherein:

said spring counter balance is mountable around said hinge joint in a first direction to facilitate mounting said articulated arm on a ceiling or the like and in a second direction to facilitate mounting on a floor or the like.

14. A portable coordinate measurement machine (CMM) for measuring the position of an object in a selected volume, comprising:

a manually positionable articulated arm having opposed first and second ends, said arm including a plurality of jointed arm segments, each arm segment including at least one position transducer for producing a position signal;

a counter-balance mounted as an integral and internal component of said articulated arm, said counter-balance comprising a spring which is machined from a metal cylinder;

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

an electronic circuit which receives the position signals from the transducers and provides a digital coordinate corresponding to the position of the probe in a selected volume.

15. The CMM of claim 14 wherein:

said spring includes a pair of opposed wider end rings and narrower internal rings.

16. The CMM of claim 15 including:

at least one locking post on one of said end rings and at least one locking post on the other of said end rings, said posts mating with complimentary locking grooves in said two arm segments.

17. The CMM of claim 16 including:

at least two locking posts on one of said end rings.

18. The CMM of claim 16 including:

an adjustment device in contact with said at least one post for urging said post circumferentially and thereby adjusting the wind-up of said spring.

19. The CMM of claim 18 wherein said adjustment device comprises a screw.

20. The CMM of claim 14 wherein:

said spring is mountable in said articulated arm in a first direction to facilitate mounting said articulated arm on a ceiling or the like and in a second direction to facilitate mounting on a floor or the like.