Motorized theodolite

PR/¢I Computer-controlled optical measuring machine Non-contact, two-dimensional, high accuracy measurement of cylindrical parts, using a combination of optics and computer technology is provided by the bench-mounted machine available from Tesa Metrology. A component held between centres, on vees or in a chuck, is traversed past a telecentdc light source to produce a magnified image of the profile which is projected onto arrays of lightsensitive photodiodes. To measure workpiece diameters, the computer counts the number of diodes that are occluded by the profile, image. Signals from a stepping motor used for traversing the part are interpreted by the computer for measuring lengths. Resolution of the optical system for measuring diameters can be varied from 0.0005 to 0.1 mm, and the stepping motor provides length measurements in 0.0025 mm increments. The machine can be used in production shops for automatically measuring carburettor needles, valves, fuel pellets, shells and other precision components for, say, the aerospace, automotive, nuclear and armaments industries. Computer facilities can be extended with a software package to provide statistical analysis of inspec-

tion data, which can be reproduced as a print-out, and/or stored on disc or tape cassette. The basic machine handles parts up to 4 mm diameter by 100 mm long, but sizes with diameter and length capacities exceeding 500 mm have been supplied. Tesa Metrology Ltd, PO Box 418, Halesfield 8/13, Telford, Shropshire TF7 4QN, UK

Motorized theodolite Claimed to be the first motorized theodolite, the Wild T2000S was developed to help faster precision industrial measurement. Wild Heerbrugg has taken its existing T2000S industrial alignment theodolite, and by incorporating two small stepper motors into the body, the telescope is motorized in both the horizontal and vertical axes. The theodolite can be driven to within 3.5 arc seconds of a predetermined pointing, with the telescope's inherent accuracy maintained to 0.5 arc seconds. Positioning can be achieved automatically, controlled by a computer either by driving the theodolite to pre-set positions as defined by the design parameters or by preprogrammed steps. A joystick control

Speedier measurement of head up display parameters is possible with this instrument from Wild Heerbrugg for manual operation is also available. Data are gathered for comparison with design values or application parameters at a speed un-matched by conventional methods. The first application of the new instrument was commissioned by Pilkington P E, who design and manufacture head-up displays for aircraft. During testing each display has around 200 reference points, and the relationship between these points, both to each other and to the pilot's eyes, is critical. Using the new theodolite, with a specifically modified eyepiece, Pilkington will be able to read electronically the positions of these points and compare them with a computer model faster and more accurately. Wild Heerbrugg (UK) Ltd, Revenge Road, Lordswood, Chatham, Kent ME5 8TE, UK

Defence technology transfer

Small cylindrical parts can be measured to high accuracy by the optical system from Tesa Metrology

PRECISION ENGINEERING

Each year Britain's Ministry of Defence Research Establishments commit large resources to pure and applied research. In the course of this defence research, ideas and concepts are developed which have potential spin offs in unrelated fields. A new organization, Defence Technology Enterprises, has been formed to help transfer this technology to industry. Companies wishing to benefit from the service may become Associate Members, by paying an

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