Abstract: A weighbridge unit for use in a conveyor weigh scale has a support for part of the conveyor belt, such as a trough or one or more idlers, a bridge carrying the support, and load cells formed by cantilever strain gauge bridge units supporting the ends of the bridge, the electrical outputs of the bridge units being summed to provide a weighbridge output signal. Cantilever arms of the load cell bridge units preferably extend in the direction of movement of the belt.

Abstract: In an acoustic ranging system, an echo signal received following a shot is repeatedly sampled and the samples digitized to produce a statistical data base representing the received echo profile which can be analyzed by various methods to determine the point on the time axis of the profile which corresponds to a wanted echo, and the degree of confidence with which the wanted echo has been identified. The number of shots taken depends upon the conditions at the site being monitored and upon the degree of confidence with which the wanted echo has been determined, and the order in which points in a multipoint system are monitored is determined by an adaptive scanning system which directs shots to different points following a system determined by a predetermined hierarchy, by the results provided by previous shots, by the conditions existing at different points, and by the receipt of outside signals.