Abstract: A measurement probe, such as a touch trigger probe, is described that comprises a stylus module attachable to a base module. The stylus module comprising a housing and a stylus holder moveably attached to the housing. The base module comprises a measurement portion for generating measurement data indicative of movement of the stylus holder relative to the housing. The stylus module has an inbuilt failure mode and thereby a substantially predetermined operational lifetime. In one embodiment, the inbuilt failure mode is provided by integrating a battery into the stylus module. Providing a mechanical failure mode in which a component of the stylus module catastrophically fails after a certain amount of usage is also described.

Abstract: A method of measurement using a measurement probe system includes the steps of (i) providing a measurement probe system having a measurement probe to a user, the measurement probe system being suitable for use with co-ordinate positioning apparatus and (ii) monitoring usage of the measurement probe system.

Abstract: A measurement probe, such as a touch trigger probe, is described that comprises a stylus module attachable to a base module. The stylus module comprising a housing and a stylus holder moveably attached to the housing. The base module comprises a measurement portion for generating measurement data indicative of movement of the stylus holder relative to the housing. The stylus module has an inbuilt failure mode and thereby a substantially predetermined operational lifetime. In one embodiment, the inbuilt failure mode is provided by integrating a battery into the stylus module. Providing a mechanical failure mode in which a component of the stylus module catastrophically fails after a certain amount of usage is also described.

Abstract: A probe arm comprises a base member 10 securable to a surface of a machine tool, and a rotatable hub 12, carrying an arm member 16 with a tool-setting probe (18 FIG. 1). The hub has a portion 22 with three radial projections (26 FIG. 2) which rotates within an aperture 24 of the base which also has three inward radial projections 30. Together these projections form stops at the operative and non-operative positions of the probe. The aperture also has three axial raised areas 42 on an annular ledge 40 which support an annular should 44 on the hub. Thus there are six points of contact between the hub and base member in the operative and non-operative positions. A biasing arrangement comprises a detent plate 46 secured to the aperture and a planar spring 48 secured to the hub by its central region. Ball bearings 56 are loosely retained in two opposite lugs (54 FIG. 6) on the spring and run around the detent plate between two pairs of detent holes (58 FIG. 5).

Abstract: An arm 12 for holding a tool-setting probe 14 in a machine tool is rotatable between an operative position and an inoperative position. The operative position is defined by elements 48,52 which form a stop against further rotary motion beyond the operative position. These elements 48,52 are arranged as a kinematic support, so that the operative position is defined in a precisely repeatable manner. Springs 40 urge the elements 48,52 together. When the arm is in the operative position, these springs are stretched by a repeatable amount, so that they provide a repeatable force, in order to increase the precision of the operative position.

Abstract: A measuring probe comprises a stylus-carrying member on which a stylus is magnetically retained. The carrying member is supported on a flat diaphragm spring for tilting movement relative to an intermediate member. The intermediate member is supported on two further diaphragms for linear movement relative to a housing. The spring rates of diaphragm and further diaphragms are chosen to give the probe the desired relative force/displacement characteristics in X,Y and Z.

Abstract: A stylus counterbalancing mechanism for a probe includes a stylus support member suspended on a resilient suspension system and connected to a spring which provides a force to counterbalance the weight of the stylus. The spring is connected to one end of a plate which is capable of sliding up and down a rod but is locked in position due to the clockwise moment produced by the spring force. The plate is unlocked from its position, when required, by movement of an actuating member. The actuating member is slidable up and down the rod and has bearing areas arranged to provide an anti-clockwise moment to the plate to unlock it and to move it along the rod to increase or decrease the spring force as required.In the probe, the actuating member includes a projection extending through the probe housing to be operable from the outside either manually or by the co-ordinate positioning machine, the machine being programmed to move the probe to engage the projection with a fixed ledge on the machine.

Abstract: An opto-electronic scale reading apparatus comprises a light source (20) which projects light via an index grating (22) onto a reflective scale (10). Light is reflected from the scale (10), passes through an auxiliary grating (36) and is incident upon an analyser grating (28), at which a plurality of periodic light patterns are formed. Light from the light source (20) travels initially parallel to the scale plane, and is subsequently deflected through 90.degree. by a beam splitter cube (26); the light is thus incident upon and reflected and off the scale (10) at 90.degree. to the scale plane. This arrangement enables large movements of the readhead in a direction perpendicular to the scale.

Abstract: An optical metrological scale produced by a rolling method, to give a profiled upper scale surface which is imparted by an embossing roller. To prevent uneven strains, which could affect the pitch of the scale, the support roller has a similar embossing profile, so that the lower side of the scale is also given a profiled surface. The embossing roller is freely rotatable, while the support roller is driven.

Abstract: A tape scale applicator (100) has a guiding channel (142) for aligning a metrological scale (126) relative to a substrate (150) to which the scale is applied. The applicator (100) is attached to a mounting bracket (153) for a read head (used to read the scale) provided on a member (154), which moves relative to the substrate (150). The applicator (100) is used to apply the scale (126) to the substrate in order to ensure that the scale (126) has a precise alignment with the read head, once the read head is connected to the mounting bracket (153). The tape scale (126) has a backing strip (140) which is removed via a second channel (170) as the scale (126) passes through the guiding channel (142).