Counter balance for coordinate measurement device

• US 8,001,697 B2
• Filed: 01/14/2011
• Issued: 08/23/2011
• Est. Priority Date: 01/20/2010
• Status: Active Grant

• Current Assignee: Faro Technologies Incorporated
• Original Assignee: Faro Technologies Incorporated
• Inventors: Danielson, David M., Barber, Marc M., Briggs, Clark H.
• Primary Examiner(s): GUADALUPE, YARITZA
• Application Number:
  US13/006,500
• Publication Number:
  US 20110173825A1
• Time in Patent Office: 221 Days
• Field of Search: 335/03, 335/56, 335/57, 335/58, 335/59, 335/60, 335/61
• US Class Current: 33/503
• CPC Class Codes: G01B 11/007 feeler heads therefor
• CPC Class Codes: G01B 21/047 Accessories, e.g. for positioning, for tool-setting, for measuring probes
• CPC Class Codes: G01B 5/012 Contact-making feeler heads therefor
• CPC Class Codes: G05B 19/401 characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes G05B19/19 takes precedence
• CPC Class Codes: G05B 19/406 characterised by monitoring or safety G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/24067 Processor stores variables, events and date in eeprom, for external monitor
• CPC Class Codes: G05B 2219/37193 Multicoordinate measuring system, machine, cmm
• CPC Class Codes: G05B 2219/40233 Portable robot
• CPC Class Codes: G05B 2219/40596 Encoder in each joint
• CPC Class Codes: G05B 2219/45061 Measuring robot

Abstract

A portable articulated arm coordinate measurement device is provided. The coordinate measurement device includes a base and an articulated arm portion having at least one arm segment. A biasing member is coupled on a first end to the base and on a second end to the articulated arm portion. The first end of the biasing member is movable between a first position and a second position. An adjuster is coupled between the base and the biasing member. The adjuster is coupled to move the first end of the biasing member from the first position to the second position.

Claims

1. A portable articulated arm coordinate measurement device (AACMM) for measuring coordinates of an object in space, comprising:

a base;

a manually positionable articulated arm portion having an opposed first end and second end, the arm portion being rotationally coupled to the base, the arm segment including a plurality of connected arm segments, each of the arm segments including at least one position transducer for producing a position signal;

a measurement device attached to the first end;

an electronic circuit for receiving the position signals from the transducers and for providing data corresponding to a position of the measurement device;

a rotation assembly coupling the second end to the base, the rotation assembly having a first axis of rotation and a second axis of rotation substantially perpendicular to the first axis of rotation;

a biasing member operably coupled between the rotation assembly and the second end to apply a force to the second end about the second axis of rotation the biasing member having at least one projection thereon; and

an adjuster having a threaded portion, the threaded portion being arranged to engage the at least one projection, wherein the force applied by the biasing member to the arm portion changes in response to movement of the adjuster.

2. The AACMM of claim 1 wherein:

the biasing member is a torsion spring; and

the force applies a first torque to the arm portion.

3. The AACMM of claim 2 wherein:

the at least one projection includes a plurality of gear teeth disposed on a third end; and

the adjuster is a worm gear engageably coupled to the plurality of gear teeth.

4. The AACMM of claim 3 wherein the worm gear is rotatably disposed within a housing, the housing being rotatably coupled to the base to rotate about the first axis of rotation.

5. The AACMM of claim 4 wherein the worm gear includes a feature on a fourth end sized to receive a tool, the worm gear rotating in response to an application of a second torque by the tool on the feature.

6. The AACMM of claim 5 wherein the housing includes a opening axially aligned with the worm gear and having a fifth end adjacent the feature, the opening being sized to receive the tool.

7. The AACMM of claim 6 wherein the torsion spring is coupled to the first end on a sixth end opposite the plurality of gear teeth.

8. The AACMM of claim 2 wherein:

the at least one projection is an arm coupled on a third end to the torsion spring; and

the adjuster includes a collar coupled between the threaded portion and the arm, wherein the collar moves the arm from a first position to a second position in response to a rotation of the adjuster.

9. A portable articulated arm coordinate measurement device (AACMM) for measuring coordinates of an object in space, comprising:

a base;

a manually positionable articulated arm portion having an opposed first end and second end, the arm portion including a plurality of connected arm segments, each of the arm segments including at least one position transducer for producing a position signal;

a measurement device attached to the first end;

an electronic circuit for receiving the position signals from the transducers and for providing data corresponding to a position of the measurement device;

a biasing member operably coupled between the base and the second end, the biasing member having at least one projection movable between a first position and a second position; and

an adjuster having a threaded portion operably coupled between the base and the biasing member, wherein the threaded portion is engaged to the at least one projection to move the at least one projection between the first position to the second position.

10. The AACMM of claim 9 wherein:

the adjuster is a worm gear; and

the at least one projection includes a plurality of gear teeth, the plurality of gear teeth being arranged to engage the worm gear.

11. The AACMM of claim 10 wherein the biasing member is a torsion spring.

12. The AACMM of claim 11 wherein the torsion spring applies a first torque on the articulatable arm when the plurality of gear teeth are in the first position and a second torque when the plurality of gear teeth are in the second position.

13. The AACMM of claim 12 further comprising a housing member coupled to the base, the housing member defining a first opening sized to receive and retain the worm gear and a second opening extending from the first opening and sized to receive a tool.

14. The AACMM of claim 9 wherein:

the adjuster includes a collar operably coupled to the threaded portion; and

the at least one projection is an arm coupled to the collar.

15. A portable articulated arm coordinate measurement device (AACMM) for measuring coordinates of an object in space, comprising:

a base;

a manually positionable articulated arm portion having an opposed first end and second end, the arm portion including a plurality of connected arm segments, each arm segment including at least one position transducer for producing a position signal;

a measurement device attached to the first end;

an electronic circuit which receives the position signals from the transducers and provides data corresponding to a position of the measurement device;

a rotation assembly rotationally coupling the second end to the base about a first axis of rotation and a second axis of rotation, the second axis of rotation being substantially perpendicular to the first axis of rotation;

a biasing member arranged within the rotation assembly and having a third end operably coupled to the second end, the biasing member having a fourth end opposite the third end, the fourth end being movable between a first position and a second position; and

an adjusting member operably coupled for rotation to the base and operably coupled to the fourth end, wherein the fourth end moves between the first position and the second position in response to a rotation of the adjusting member.

16. The AACMM of claim 15 wherein the rotation assembly further includes a housing, the housing defining a first opening sized to receive the adjusting member.

17. The AACMM of claim 16 wherein the biasing member is a torsion spring having a plurality of gear teeth on the fourth end, and the adjusting member is operably coupled to the gear teeth.

18. The AACMM of claim 17 wherein:

the adjusting member includes a worm screw portion; and

the housing includes a second opening extending from a fifth end of the first opening, the second opening sized to receive a tool.

19. The AACMM of claim 15 wherein the adjuster includes a threaded member and a collar disposed between the threaded member and the fourth end, the collar having a threaded portion engaged with the threaded member.

20. The AACMM of claim 19 further comprising an arm coupled between the collar and the fourth end, wherein the arm moves the fourth end between the first position and the second position in response to rotation of the threaded member.