GB724527A - - Google Patents

Abstract

724,527. Automatic control systems. EXACT WEIGHT SCALE CO. March 26, 1952 [March 29, 1951], No. 7760/52. Drawings to Specification. Class 38 (4). In a control system electronic means produce voltages dependent on a controllable physical characteristic of each one of a series of successive articles, the voltages being applied to condensers by the articles being tested and the condensers being connected together to obtain an average control factor. The invention is applied to a beam-type weight-checking machine of the type in which the weighing beam moves the plates of an electric condenser to vary the frequency of an oscillator combined with a discriminator circuit to produce a voltage dependent on the deviation of the weight of each of a series of filled packages passing through the machine. The deviation voltages are utilised in the manner described below to control the filler spout of a dispenser from which the packages are filled before being transported on a conveyer to the weighing section of the machine. As each package leaves the weighing section of the machine a beam of light associated with a photocell is interrupted. Electrical impulses are thus produced and a stepping switch is operated at each impulse to charge a condenser to the weight deviation voltage corresponding to the package producing the impulse. Five condensers so charged are then automatically connected in parallel to produce an average weight-deviation voltage which serves to control the filler spout of the dispenser. The arrangement operates continuously to produce an average weight deviation voltage for each successive group of five packages. In a modification, according to the position of a manually operated switch, four or nine condensers may be charged in succession so that the weight deviation of a corresponding number of packages may be averaged. In this arrangement the weight deviation of one package is missed between the groups averaged. In another modification further condensers are charged to the average deviation voltages of successive groups and a group average obtained by paralleling these condensers. In this manner an average of two, five or ten groups of five may be obtained.