Abstract: Metrology apparatus is described that includes a first structure rotatably connected to a second structure by a bearing arrangement. The bearing arrangement includes at least a first friction bearing including parts in sliding contact during rotation of the first structure relative to the second structure. The apparatus includes at least one magnet that relieves the load on the first friction bearing. Multiple magnets, provided in an attracting or repelling arrangement, may be used. The metrology apparatus may include an articulating probe head for a coordinate positioning apparatus.

Abstract: A rotary gas bearing is described that comprises a first part rotatable relative to a second part. The first part comprises a support member and a first portion and a second portion attached to the support member. The first portion comprises a first bearing surface and the second portion comprising a second bearing surface. Both the first portion and the second portion are attached to the support member by screw thread connections. The second part may comprise complimentary bearing surfaces. Epoxy may be used to fix the first and/or second portions to the support member. A method of determining the bearing working gap by measuring gas flow through the bearing is also described.

Abstract: A metrology apparatus including a body and a first member rotatable relative to the body about a first axis of rotation, said first axis being defined by first bearing and a first motor for actuating rotation of the first member relative to the body about the first axis of rotation. A surface sensing device is attachable to the first member such that the surface sensing device can move with the first member, relative to the body. The first motor may include a first magnet and at least one metal coil spaced apart along the first axis and mounted such that the first magnet and the at least one metal coil are moveable relative to one another.

Abstract: A method and apparatus for measuring a surface using a surface sensing device mounted on a scanning head on a member of a coordinate positioning apparatus. The coordinate positioning apparatus may be operated to produce relative movement between the scanning head and the surface profile and the scanning head includes a drive for producing rotational movement of the surface sensing probe about one or more axis. The coordinate positioning apparatus is driven to provide relative movement between the member and the surface profile in a circular path and the scanning head is driven to move the surface sensing device about said one or more axes, such that the surface sensing device maintains a nominally constant lead angle. The motion of the coordinate positioning apparatus and scanning head is synchronous.

Abstract: A method of fabricating a bearing surface for a gas or air bearing is described. The method comprises taking a bulk bearing portion having at least one bearing surface region and providing a coating on the bearing surface region to define at least one gas pocket. The at least one gas pocket has a depth substantially equal to the thickness of the coating. In one example, laser ablation is used to remove part of the coating to form the gas pockets. The coating may be an anodised coating and the bulk bearing portion may be formed from aluminium. An air bearing component formed using the method is also described.

Abstract: A method of fabricating a bearing surface for a gas or air bearing is described. The method comprises taking a bulk bearing portion having at least one bearing surface region and providing a coating on the bearing surface region to define at least one gas pocket). The at least one gas pocket has a depth substantially equal to the thickness of the coating. In one example, laser ablation is used to remove part of the coating to form the gas pockets. The coating may be an anodized coating and the bulk bearing portion may be formed from aluminium. An air bearing component formed using the method is also described.

Abstract: A method and apparatus for measuring a surface using a surface sensing device mounted on a scanning head on a member of a coordinate positioning apparatus. The coordinate positioning apparatus may be operated to produce relative movement between the scanning head and the surface profile and the scanning head includes a drive for producing rotational movement of the surface sensing probe about one or more axis. The coordinate positioning apparatus is driven to provide relative movement between the member and the surface profile in a circular path and the scanning head is driven to move the surface sensing device about said one or more axes, such that the surface sensing device maintains a nominally constant lead angle. The motion of the coordinate positioning apparatus and scanning head is synchronous.

Abstract: A method and apparatus for measuring a surface using a surface sensing device mounted on a scanning head on a member of a coordinate positioning apparatus. The coordinate positioning apparatus may be operated to produce relative movement between the scanning head and the surface profile and the scanning head includes a drive for producing rotational movement of the surface sensing probe about one or more axis. The coordinate positioning apparatus is driven to provide relative movement between the member and the surface profile in a circular path and the probe head is driven to move the surface sensing device about said one or more axes, such that the surface sensing device maintains a nominally constant lead angle. The motion of the coordinate positioning apparatus and probe head is synchronous.

Abstract: An analogue probe for use with a coordinate positioning machine. The analogue probe comprises a temperature actuator which can be modulated so as maintain the temperature of at least a part of the analogue probe at a substantially constant predetermined temperature.

Abstract: A method and apparatus for measuring a surface using a surface sensing device mounted on a scanning head on a member of a coordinate positioning apparatus. The coordinate positioning apparatus may be operated to produce relative movement between the scanning head and the surface profile and the scanning head includes a drive for producing rotational movement of the surface sensing probe about one or more axis. The coordinate positioning apparatus is driven to provide relative movement between the member and the surface profile in a circular path and the probe head is driven to move the surface sensing device about said one or more axes, such that the surface sensing device maintains a nominally constant lead angle. The motion of the coordinate positioning apparatus and probe head is synchronous.

Abstract: A method of fabricating a bearing surface (11,13) for a gas or air bearing (2) is described. The method comprises taking a bulk bearing portion (30; 44) having at least one bearing surface region and providing a coating (32; 42) on the bearing surface region to define at least one gas pocket (34; 40). The at least one gas pocket (34; 40) has a depth substantially equal to the thickness of the coating (32; 42). In one example, laser ablation is used to remove part of the coating (32; 42) to form the gas pockets (34; 40). The coating (32; 42) may be an anodised coating and the bulk bearing portion (30) may be formed from aluminium. An air bearing component formed using the method is also described.

Abstract: A rotary gas bearing is described that comprises a first part rotatable relative to a second part. The first part comprises a support member and a first portion and a second portion attached to the support member. The first portion comprises a first bearing surface and the second portion comprising a second bearing surface. Both the first portion and the second portion are attached to the support member by screw thread connections. The second part may comprise complimentary bearing surfaces. Epoxy may be used to fix the first and/or second portions to the support member. A method of determining the bearing working gap by measuring gas flow through the bearing is also described.

Abstract: A metrology instrument, such as a probe, probe head, stylus or stylus arm, for mounting on a coordinate position apparatus. The metrology instrument is at least partially constructed from at least one sheet of thermally stable metallic material which is folded to form a three dimensional structure. The at least one sheet of thermally stable material is utilized in the metrology loop of the metrology instrument.

Abstract: A method and apparatus for measuring a surface using a surface sensing device mounted on a scanning head on a member of a coordinate positioning apparatus. The coordinate positioning apparatus may be operated to produce relative movement between the scanning head and the surface profile and the scanning head includes a drive for producing rotational movement of the surface sensing probe about one or more axis. A desired measurement profile on the surface which the surface sensing device will track and the desired motion of the orientation of the surface sensing device as the surface' sensing device follows the measurement profile are defined. This data is used to derive the required path of the relative motion between the member of the coordinate positioning apparatus and the surface, such that the surface sensing device prescribes a trajectory along the measurement profile.

Abstract: A bearing arrangement for an articulatable support includes bearing assemblies. In one embodiment, the assemblies have a ball and aperture having sliding contact at discrete areas during relative rotation. In another embodiment, the sliding contact may be formed at a ball and a plastics (e.g. P.T.F.E. support). Resilient displacement of the bearing contact along a rotational axis is provided by planar spring supports and a rigid support is provided by supports.

Abstract: A bearing arrangement for an articulatable support (6) comprises bearing assemblies (20/28, 22/29, 24/30 and 26/32). In one embodiment the assemblies comprise a ball (20, 22, 24, 26) and aperture (40 FIG. 2) having sliding contact at discrete areas (36) during relative rotation. In another embodiment the sliding contact may be formed at a ball (20,22,24,26) and a plastics e.g. P.T.F.E. support (84, 85 FIGS. 10 and 11). Resilient displacement of the bearing contact along a rotational axis (A and B) is provided by planar spring supports (28, 32) and rigid support is provided by supports (29 and 30).

Abstract: A bearing arrangement for an articulatable support (6) comprises bearing assemblies (20/28, 22/29, 24/30 and 26/32). In one embodiment the assemblies comprise a ball (20, 22, 24, 26) and aperture (40 FIG. 2) having sliding contact at discrete areas (36) during relative rotation. In another embodiment the sliding contact may be formed at a ball (20, 22, 24, 26) and a plastics e.g. P.T.F.E. support (84, 85 FIGS. 10 and 11). Resilient displacement of the bearing contact along a rotational axis (A and B) is provided by planar spring supports (28, 32) and rigid support is provided by supports (29 and 30).