Apparatus for determining the projected area of objects

... 959, 787. Electric selective signalling systems. NEW ELECTRONIC PRODUCTS Ltd. Nov. 7, 1960, No. 38181/60. Heading G4H. Apparatus for measuring the area of objects such as planks of wood P comprises a plurility of micro-switches 21 or photo-electric devices arranged along the length of P, perpendicular to the direction of travel of conveyer belt 4, and each controlling a relay 22 so that the number of switches 19 which are closed depends on the length of P, and width sensing means, e.g. photo-cell 31 and lamp 30, controlling relay 32, opens a switch 33 in the common channel 18 so as to allow signals, applied in succession to the individual channels 17, to step on counter 40 for a time dependent on the width of P. In this way bursts of signals are applied to counter 40, the number of signals in each burst being determined by the length of P, and the number of bursts being determined by the width of P. Counter 40 may accumulate the total area of a number of planks and its contents may be read ...