Renishaw Plc

Renishaw Metrology Limited

Stephen E Lummes

David R McMurtry

Brian C Henning

Mark James Andrew Holmes

Robert B Morrison

Jonathan Paul Fuge

David Allan Wright

Tim Prestidge

William F Stephens

Andrew J Harding

Jonathan S Sullivan

Martin P Spivey

Stuart Kersten Campbell

Mark Cole

A surface finish stylus is described that includes an elongate stylus shaft and a contact element protruding from the elongate shaft for contacting a surface to be measured. The contact element is deformable and the stylus shaft includes a clamp for retaining the contact element, the contact element being deformed by the clamp. The contact element may comprise a metal, such as chromium steel or nitinol. The contact element includes one or more regions of weakness to cause a required deformation when retained by the clamp. The surface finish stylus may be used with a surface finish measurement probe or the like.

Surface finish stylus

A surface finish stylus and associated methods for a multi-directional scanning probe the stylus having an elongate stylus shaft having a longitudinal axis and one or more contact elements protruding from the elongate shaft for contacting a surface to be measured. The one or more contact elements are configured to enable measurement of surface finish during motion of the stylus shaft relative to a surface along a measurement direction that is non-parallel to the longitudinal axis. The multi-directional scanning probe may be carried by a coordinate measuring machine or machine tool.

A machine tool is provided with a toolsetting probe mounted on a bed or table, and a workpiece-sensing probe which can be mounted in a movable spindle. Both probes are calibrated by using them to make measurements against each other. The arbitrary length of the workpiece-sensing probe is used to calibrate the toolsetting probe, rather than using a pre-calibrated artefact of known length mounted in the spindle. A stylus disc of the toolsetting probe has a pre-calibrated size or dimension, and the workpiece-sensing probe is calibrated with respect to that. This obviates the need for skilful manual calibration procedures using pre-calibrated artefacts and manual measurement tools.

Calibration of measurement probes

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.

Modular measurement probe

A touch probe () is disclosed comprising a probe body () housing first locating elements (), a stylus holder () having second locating elements () which co-operate with the first locating elements to locate the stylus holder within the probe body, and a bias () to urge the first and second locating elements into contact, wherein an element () is provided to damp motion between the probe body and the stylus holder. The element may slow a relative movement between the locating elements perhaps by resisting the urging of the bias or absorb energy produced by a relative movement between the probe body and stylus holder. The element may be slidably or rotatably mounted with respect to one of the probe head and stylus holder.

Touch probe

A probe arm comprises a base member securable to a surface of a machine tool, and a rotatable hub , carrying an arm member with a tool-setting probe ( FIG. ). The hub has a portion with three radial projections ( FIG. ) which rotates within an aperture of the base which also has three inward radial projections . Together these projections form stops at the operative and non-operative positions of the probe. The aperture also has three axial raised areas on an annular ledge which support an annular should 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 secured to the aperture and a planar spring secured to the hub by its central region. Ball bearings are loosely retained in two opposite lugs ( FIG. ) on the spring and run around the detent plate between two pairs of detent holes ( FIG. ). In the operative and non-operative positions, the ball bearings rest on radially-extending edges ( A FIG. ) of the detent holes and thus the axial force of the spring also provides a component of force in a tangential direction, thereby causing a rotational force.

Probe arm for machine tool

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.

Measuring probe

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.

Stylus counterbalancing mechanism for a measuring probe

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.

Growing community of inventors

Stroud, United Kingdom

Stephen E Lummes