GB901301A - Method of and means for calibrating belt weighing machines - Google Patents

Abstract

901,301. Electric selective signalling &c. BOEKELS, H., and BOEKELS, K. J., [trading as BOEKELS & CO., HANS]. Oct. 29, 1959 [Dec. 26, 1958], No. 45757/61. Divided out of 901,300. Class 40 (1). A device for calibrating belt weighing apparatus of the kind in which a signal is obtained proportional to the product of the weight of material carried by the belt and the speed of the belt, comprises an electric circuit arranged to actuate a counter on each operation of a first switch whereby the total figure recorded by the counter is dependent both on the rate of operation of the first switch and on the duration of time for which a second switch holds the circuit energized. The signal produced by the weighing apparatus whose amplitude represents the product of the instantaneous weight and the belt speed rotates a vane 19, Fig. 2, to supply impulses to a relay R whose contacts R1 register a count on counter C, as described in Specification 901,300. To calibrate the apparatus, counter C is disabled and a calibrating counter CC enabled by means of switches M1, M2, respectively. A first switch 28 is opened and closed repeatedly by a cam 29 operated by movement of the conveyer belt 1, and registers on the counter CC while a second switch 27 is closed. At the start of a calibration cycle, this switch 27 is open and a known weight is placed on the weighing apparatus. The resulting signal operates, via relay contact R2, solenoid 23, pawl 24 and ratchet wheel 25, a cam 26 closing contacts 27 for a period of time dependent on the calibrating weight and the belt speed. Thus the total number of units recorded on the counter during one revolution of cam 26 is proportional to the belt speed multiplied by the duration of the period, i.e. it is inversely proportional to the calibrating weight.