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1. (WO1990007097) PROCEDE ET APPAREIL PERMETTANT DE BALAYER LA SURFACE D'UNE PIECE D'USINAGE
Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

CLAIMS

1. A method of scanning a surface of a workpiece using surface detecting device mounted on a support within a three dimensional reference framework, comprising the steps of:

producing relative movement between the support and the surface along a path whereby the surface detecting device passes over the surface,

producing relative movements of the surface detecting device transverse to the instantaneous path direction, and,

bringing the surface detecting device into a
pre-determined spatial relationship with the workpiece surface.

2. A method as claimed in claim 1 and further comprising the steps of:

determining the positions of the support at a
plurality of locations within the reference framework relative to a datum position;

determining the instantaneous positions of the surface detecting device relative to the support when the support is at each of said locations; and

using the results of said determinations to determine the positions relative to said reference framework of a plurality of points on the surface being scanned.

3. A method as claimed in claim 1 and in which said relative movement between the surface to be scanned and the support takes place at constant velocity.

4. A method as claimed in claim 3 and in which the support is driven by a machine at constant velocity to produce said relative movement between the surface to be scanned and the motorised head.

5. A method as claimed in claim 1 and in which the relative movements of the surface detecting device
transverse to the instantaneous path direction are
oscillating movements.

6. A method as claimed in claim 5 and in which the oscillating movements take place in two orthogonal
directions transverse to the instantaneous path
directions.

7. A method as claimed in claim 6 and wherein the surface to be scanned is a cylindrical surface in or on the workpiece and which has a longitudinal axis, and the path has at least a component of direction parallel to said longitudional axis.

8. A method as claimed in claim 1 and in which the support is a scanning head having at least one axis and the transverse movements of the surface detecting device relative to the surface are oscillating pivoting movements about said at least one axis of the head.

9. A method as claimed in claim 1 and in which the support is a scanning head having at least one axis and the transverse movements of the surface detecting device relative to the surface are oscillating translating movements relative to said at least one axis of the head.

10. A method as claimed in claim 1 and wherein the surface detecting device is a stylus having a surface-contacting tip, and the pre-determined
relationship thereof with the surface is a relationship which the surface contacting tip is in contact with the surface.

11. A method as claimed in claim 1 and wherein the surface detecting device is a touch trigger probe having stylus with a surface-contacting tip, and the
pre-determined relationship thereof with the surface is relationship in which the surface contacting tip is in contact with the surface.

12. A method as claimed in claim 2 and wherein the surface detecting device is an analogue probe having a stylus with a surface-contacting tip, the pre-determined relationship thereof with the surface being a relationsh in which the surface contacting tip is in contact with t surface, the probe having transducers whereby the positi of the stylus relative to the probe may be determined, t method comprising the further steps of:

determining from the transducers of the analogue pro the position of the stylus relative to the probe at each one of said plurality of locations, and,

using the results of such determination in determini the positions of points on the surface in said co-ordinat framework relative to said datum position.

13. A method as claimed in claim 10 or claim 12 and wherein the stylus carries transducers whereby any deformation of the stylus due to contact with the surface may be determined, the method further comprising the step of:
determining from the transducers on the stylus the amount by which the stylus may be deformed, and, using the results of such determination in determining the positions of points on the surface in said coordinate framework relative to said datum position.

14. A method as claimed in claim 1 and wherein the surface detecting device is a non-contact probe and the
pre-determined relationship thereof with the surface is a relationship in which the probe is positioned at a
pre-determined distance from the surface.

15. A method as claimed in claim 13 and wherein the probe is an optical probe.

16. A method of scanning a surface of a workpiece
comprising the steps of:

mounting a scanning head on a machine,

mounting a surface detecting device on the scanning head,

producing relative movement between the surface being scanned and the scanning head,

moving the surface detecting device transversely to the instantaneous direction of said relative movement to bring the surface detecting device into a pre-determined relationship with the surface being scanned at a pluralit of positions.

17. A method as claimed in claim 16 wherein the machine has transducers whereby the instantaneous position of the head in a three dimensional co-ordinate framework may be determined relative to a datum position, the motorised head has transducers whereby the instantaneous position o the surface detecting device relative to the head may be determined, the method comprising the further steps of: determining from the transducers on the machine and on the head the position within said co-ordinate framework of the surface detecting device at each one of said plurality of positions, and,

using the results of such determination in determining the positions of points on the surface in said co-ordinate framework relative to said datum position.

18. A scanning head for use with a machine in scanning the surface of a workpiece comprising:

means defining an axis,

a surface detecting device mounted on the head,

drive means for producing movement of the surface detecting device relative to said axis, and

means for reducing the effect on the machine of the reaction forces produced in the head as a result of said movement of the surface detecting device.

19. A scanning head for use in scanning the surface of a workpiece comprising:

a fixed part and a movable part,

an air bearing on which the movable part is supported and which defines an axis of movement for the movable head,

a surface detecting device carried by the movable part, and,

drive means for causing movement of the movable part relative to said axis to position the surface-detecting device relative to the surface to be scanned.

20. A scanning head according to claim 18 or claim 19 and wherein the head has means defining two orthogonal axes relative to which the surface-detecting device is movable.

21. A scanning head according to claim 18 or claim 19 and wherein each axis of the head relative to which the surface detecting device is movable is a pivoting axis.

22. A scanning head according to claim 18 or claim 19 and wherein each axis of the head relative to which the surface detecting device is movable is a translational axis.

23. A scanning head according to claim 18 or claim 19 and wherein the head includes position-determining transducers for determining the position of the surface detecting device relative to each axis of the head

24. A scanning head according to claim 18 or claim 19 and wherein each of the drive means is a constant torque motor.

25. A scanning head according to claim 18 or claim 19 and wherein the surface detecting device is a stylus having a surface-contacting tip.

26. A scanning head according to claim 18 or claim 19 and wherein the surface detecting device is a touch trigger probe including a stylus having a surface-contacting tip.

27. A scanning head according to claim 18 or claim 19 and wherein the surface detecting device is an analogue probe including a stylus having a surface-contacting tip.

28. A scanning head according to claim 18 or claim 19 an wherein the surface detecting device is a non-contact probe.

29. A scanning head according to claim 28 and wherein th surface detecting device is an optical probe.

30. A scanning head according to claim 27 and wherein th analogue probe includes position-determining transducers for determining the instantaneous position of the stylus relative to the probe.

31. A scanning head according to claim 25 or claim 27 an wherein the stylus carries transducers whereby any deformation of the stylus due to contact with the surface may be determined.

32. A scanning head as claimed in claim 18 and in which the means for reducing the effect on the machine of the forces produced in the head comprises a mass within the head which is rotationally accelerated to produce an equa and opposite reaction to said forces.

33. A scanning head as claimed in claim 32 and wherein the drive means in the head is an electric motor, the parts of which are mounted for relative rotation in opposite directions.

34. Apparatus for scanning the surface of a workpiece comprising a machine supporting a scanning head according to any one of claims 18 to 31 for movement in a
three-dimensional co-ordinate framework and wherein the machine includes position-determining transducers for determining the instantaneous position of the head within said framework, the apparatus further comprising control means for establishing a pre-determined relationship between the surface detecting device and the surface being scanned.

35. Apparatus as claimed in claim 34 and further
comprising data gathering means controlled by the control means for gathering position data from the position determining transducers on the machine.

36. Apparatus according to claim 35 as dependent on claim 23 and wherein the data gathering means additionally receives position data from the position-determining transducers in the head.

37. Apparatus according to claim 35 as dependent on claim

30 and wherein the data gathering means additionally receives position data from the position determining transducers in the probe.

38. Apparatus according to claim 35 as dependent on claim

31 and wherein the data gathering means additionally receives data from the transducers carried by the stylus.

39. A scanning head for use with a machine in scanning the surface of a workpiece comprising:

a base for connection to a machine,

a first rotatable part supported on the base for rotation about a first axis,

a second rotatable part supported on the first
rotatable part for rotation about a second axis orthogonal to the first axis,

a surface detecting device secured to the second rotatable part, and

drive means causing rotation of the first and second rotatable parts,

wherein the drive means are constant torque motors which are operable as positioning and/or bias motors to maintain the surface detecting device in a pre-determined relationship with the surface being scanned and to oscillate the surface detection device over the surface.