Abstract: A method of mounting rotary scale member on machine part includes: locating rotary scale member on machine part such that scale axis and axis of rotation are substantially parallel, and subsequently arranging at least a first radial adjustment device to contact both machine part and rotary scale member, and manipulating the at least first radial adjustment device to radially displace body of rotary scale member. At least the majority of any radial reaction force, generated as a result of the interaction of at least one of the flexures with a radial stop member against which it is radially pressed, and which is imparted on the at least first radial adjustment device by rotary scale member in opposition to the radial displacement of the rotary scale member, is directed into, and reacted by, the machine part via the contact between the at least first radial adjustment device and the machine part.

Abstract: A method of mounting a rotary scale member on a part, the rotary scale member including a body on which a series of position features defining a scale is provided, and at least one mounting flexure configured to engage the part, the method including: force-fitting the rotary scale member and the part together, whereby the at least one flexure is displaced by the part and thereby urged via a radial reaction force into engagement with the part so as to form a friction fit with the part such that the body of the rotary scale member self-locates at an initial default radial location with respect to the part; and tweaking the radial location of the body relative to the part away from its initial default radial location to a new radial location.

Abstract: A sealed linear encoder apparatus provides a measure of relative displacement of two relatively movable members. The sealed linear encoder apparatus includes at least one elongate sealing lip wherein at least a sealing portion of the elongate sealing lip is held in tension along its length.

Abstract: A sealed encoder module for mounting onto a machine so as to measure relative displacement of first and second parts of the machine. The sealed encoder module can comprise, a scale, a readhead comprising a scale signal receiver, and an integral protective housing which encapsulates at least the scale and said scale signal receiver. The sealed encoder module can be configured to determine and output diagnostic information regarding a scale signal detected by the readhead.

Abstract: A rotary scale apparatus for an encoder apparatus including a planar disc on which at least one track including scale features is provided, in which the planar disc includes a hole through its centre for receiving a cylindrical shaft, and in which the rotary scale member includes at least three cantilevered spring members which are provided substantially in plane with the planar disc and spaced around the edge of the hole, for engaging with, and radially locating the disc on, a cylindrical shaft inserted therethrough.

Abstract: A sealed encoder module for mounting onto a machine so as to measure relative displacement of first and second parts of the machine. The sealed encoder module can comprise, a scale, a readhead comprising a scale signal receiver, and an integral protective housing which encapsulates at least the scale and said scale signal receiver. The sealed encoder module can be configured to determine and output diagnostic information regarding a scale signal detected by the readhead.

Abstract: A sealed encoder module for mounting onto a machine so as to measure relative displacement of first and second parts of the machine. The sealed encoder module can comprise, a scale, a readhead comprising a scale signal receiver, and an integral protective housing which encapsulates at least the scale and said scale signal receiver. The sealed encoder module can be configured to determine and output diagnostic information regarding a scale signal detected by the readhead.

Abstract: An encoder apparatus comprising a scale and a readhead assembly comprising a scale signal receiver. The scale and the scale signal receiver are located within a protective housing which is configured to protect them from contamination located outside the protective housing and comprises a seal through which the scale signal receiver can be connected to a part outside the protective housing. The arrangement of the scale signal receiver inside the protective housing is independent of the scale and protective housing.

Abstract: An encoder apparatus comprising a scale and a readhead assembly comprising a scale signal receiver. The scale and the scale signal receiver are located within a protective housing which is configured to protect them from contamination located outside the protective housing and comprises a seal through which the scale signal receiver can be connected to a part outside the protective housing. The arrangement of the scale signal receiver inside the protective housing is independent of the scale and protective housing.

Abstract: A sealed linear encoder apparatus provides a measure of relative displacement of two relatively movable members. The sealed linear encoder apparatus includes at least one elongate sealing lip wherein at least a sealing portion of the elongate sealing lip is held in tension along its length.

Abstract: An encoder apparatus comprising a scale and a readhead assembly comprising a scale signal receiver. The scale and the scale signal receiver are located within a protective housing which is configured to protect them from contamination located outside the protective housing and comprises a seal through which the scale signal receiver can be connected to a part outside the protective housing. The arrangement of the scale signal receiver inside the protective housing is independent of the scale and protective housing.

Abstract: A sealed encoder module for mounting onto a machine so as to measure relative displacement of first and second parts of the machine. The sealed encoder module can comprise, a scale, a readhead comprising a scale signal receiver, and an integral protective housing which encapsulates at least the scale and said scale signal receiver. The sealed encoder module can be configured to determine and output diagnostic information regarding a scale signal detected by the readhead.

Abstract: Position measurement apparatus, such as hexapod co-ordinate measuring machine, is described that comprises a thrust frame and a metrology frame. The thrust frame comprises a load carrying base connected to a moveable platform by a plurality of powered extendable legs. The metrology frame comprising a metrology base attached to the load carrying base by a base attachment mechanism such as kinematic mounts. The base attachment mechanism is arranged to prevent any distortions of the load carrying base being transmitted to the metrology base.

Abstract: A pivot joint assembly is described that includes a multi-axis revolute joint portion and a ball joint portion. The multi-axis revolute joint portion provides rotational movement about two or more revolute axes that substantially intersecting at an intersection point. The ball joint portion comprising a ball located in the vicinity of said intersection point. The pivot joint assembly allows separate coupling of load members and metrology members to one or more platforms. A hexapod co-ordinate measuring machine including such pivot joint assemblies is also described.

Abstract: Position measurement apparatus, such as hexapod co-ordinate measuring machine, is described that comprises a thrust frame and a metrology frame. The thrust frame comprises a load carrying base connected to a moveable platform by a plurality of powered extendable legs. The metrology frame comprising a metrology base attached to the load carrying base by a base attachment mechanism such as kinematic mounts. The base attachment mechanism is arranged to prevent any distortions of the load carrying base being transmitted to the metrology base.

Abstract: An extendable leg assembly for a measuring machine, such as a co-ordinate measuring machine, is described. The extendable leg assembly has a first end and a second end and comprises metrology apparatus for measuring the separation between the first end and the second end. The metrology apparatus comprises one or more elongate metrology members having a low coefficient of thermal expansion. The extendable leg assembly may be attached to one or more platforms by a pivot joint.