Patent GB-765456-A (GB)
Title: Improvements connected with weighing apparatus
Inventor: COOKE ERNEST ALBERT
IPC: G01G23/375
Filed: 1953-05-26
Abstract: 765,456. Electric selective signalling. AVERY, Ltd., W. & T. Aug. 25,1954 [May 26, 1953], No. 14592/53. Class 40 (1). [Also in Group XL (b)] Weighing apparatus comprises means for deflecting a member in accordance with the weight, means for searching for this member so as to operate contacts associated with both the searching means and the member and means for generating pulses at a rate proportional to the speed of movement of the searching member so as to produce a count representative of the weight until the contacts are operated by the coincidence of the member and the searching means. As shown (Fig. 1) the invention is applied to measuring the weight of material on an endless belt conveyer which is supported from a load counter balancing mechanism and receives a continuous stream of material which is discharged from one end of the conveyer. The load counter-balancing mechanism is linked to a lever h which is deflected downwardly to an extent dependent on the weight. A second lever h<SP>2</SP> rests lightly on a stop j on the first and carries contacts k. A disc b having a series of apertures bl around its periphery is driven by the same motor as drives the conveyer and produces pulses by interrupting the light reaching a cell d from a source c at a rate proportional to conveyer speed. Rotating with disc b are two cams e and l which reciprocate a searching member f to engage lever h<SP>2</SP> and open contacts ml at the top of the travel of searching member f respectively. In operation levers h and h2 adopt a downward deflection representative of the weight to be measured. Cam e lifts member f upwards at a speed proportional to conveyer speed until member h<SP>2</SP> is lifted away from h and contacts k closed. Contacts k then close the circuit of a counter and the photo-electrically generated pulses are counted. Counting continues until cam opens its contacts m<SP>1</SP> at the end of the upward travel of search member f. In an alternative arrangement (Fig. 3) for measuring individual containers an independent constant speed motor drives the apertured disc b while the lever h is deflected upwardly by the arrival of a container on the weighing platform. The arrival of the container starts the motor driving the apertured disc and cams el at constant speed and counting commences immediately continuing until the search member f opens the contacts k<SP>1</SP>. This resets the counter and prints the tare weight of the container, and the counter immediately starts counting again. Member f closes a second pair of contacts k which initiate a supply of material to the container. Member f rises more quickly than ,does lever h as the feed enters the container contacts k remain closed until the counter gives out a signal after a predetermined number of pulses have been counted stopping the driving motor and with it cams e and l and member f and applying a link to disc b. The feed now continues until lever h reaches lifts h<SP>2</SP> opening contacts k again thus stopping the feed operating a reverse contactor which restores cam e until contacts m<SP>1</SP> open and reset the counter.