Draw wire sensors offer precision in operating theatres

Utilisation and cost efficiency are critical in medical operating theatres. The latest operating tables, for example, offer numerous functions for precise handling of the patient, but need to be efficient and cost-effective. Typically, operating tables are modular in design and offer multiple adjustment options for the precise positioning of the patient during an operation. As well as the height of the table, the horizontal position and several angular functions for the head, torso and legs also need to be adjustable. In order to enable these adjustments, suitable measuring devices are required. Draw-wire displacement sensors are ideal for this, combining a compact design with high precision and long service life. The sensors can integrate easily with the operating table, offering an excellent price/performance ratio for the customer. The principle of a draw-wire displacement sensor is relatively straightforward, hence its inherent reliability. The sensor works rather like a tape measure, except with a draw-wire sensor; the user does not have to read off the measurement of the extended tape. The rotation of the drum on which the steel wire is wound is measured automatically and the measurement signal is output in either analogue or digital formats. The drum itself incorporates a long-life spring drive, which ensures the steel wire is rewound. The latest X-ray machines also require precise positioning so that they can provide high quality images of patients. The digital camera on these machines has to be aligned exactly with the X-ray tubes so that high resolution recordings can be produced. The cameras, X-ray tubes, the table and the wall stands can be moved on several axes, providing maximum flexibility. Draw-wire sensors can be used to position the mechanical moving parts. The synchronisation controller in the X-ray unit then uses the displacement data from the sensors to ensure that the X-ray tube and camera move parallel to each other. Draw-wire sensors can also be used to measure angles on operating tables and flexible surgical arms.