Patent GB-952365-A (GB)
Title: Automatic weighing apparatus
IPC: G01G13/00
Filed: 1960-10-11
Abstract: 952,365. Automatic feed weighers. T.TARUKAWA. Oct.11, 1960 [Oct. 14, 1959(2)], No. 34833/60. Heading G1W. An automatic weighing apparatus comprises in combination a feeding device for the material, a measuring tank for material from the feeding device, a weighing device combined with the tank, discharge means for the material in the tank, contacts in the circuits to the feeding device and to the discharge means and a change over device which includes first and second operating devices, such as electromagnets Mg1, Mg2 each controlling one of the contacts either switches S1 or S2, Fig. 1, or change-over contacts c 1  or c 2 , Fig. 2, the first operating device closing one contact to make the discharge means operate and the second operating device opening one contact so as to stop the supply of the feeding device under the control of the weighing device when the material in the measuring tank reaches a predetermined quantity. Fig. 1 shows a circuit for automatically filling a tank M on-the weighing machine. Pressing a switch PS initiates discharge and energizes the electromagnet Mg1 closing the switch S1 in series with an electromagnet MgO connected to a lever L which opens a shutter D of the tank. A time limit switch TCD operates energizing the electromagnet Mg2 which opens the switch S1 allowing the shutter D to close under spring action. The time limit switch TCF operates through the electromagnet switch MgS1 to operate the motor MO1 to drive the screw conveyer, feeding material from the tank F to the tank M. At the completion of filling the balance beam W pivots, the switch SL opens and the time limit switch TCF operates to stop the motor. The switch TCF may be replaced by a switch S2 under the control of the time limit switch TCD. For the automatic discharge of material in the tank, pressing the push button PS<SP>1</SP>, Fig. 2, magnetises the electromagnet Mg2 closing contact C2 of a changeover device to close the shutter via contact D2, electromagnetic switch MgS2 and motor MO2. The shutter operates through a cable wound on a drum the shaft of which has a spring urged clutch connecting it with the shaft of the motor MO2. The clutch is operated by a pivoted lever L connected to the core of an electromagnet MgO connected through a time limit switch TCD<SP>1</SP> to the change over device, when the clutch disengages the shutter is free to open when the electromagnet energizes. When the shutter closes the circuit is completed through contact D2, switch SL, contact c 2 , supply E, electromagnetic switch MgS1 to start a motor MO1 to feed material to the tank M. When the tank M fills the beam W pivots and closes switch SH and the electromagnet Mg1 is energized and closes contact c 1  to energize the electromagnet MgO through time limit switch TCD<SP>1</SP> to release the clutch and open the shutter to discharge the material. The circuit shown in dotted lines may be used instead of switches PS<SP>1</SP>, SH to discharge the material and to feed automatically. For automatic discharge or for automatic feeding the tank M may be connected to the balance beam W by a cable. A circuit similar to that shown in Fig. 1 but for automatic discharge incorporates switches SL, SH and no time limit switches. In another circuit the switch S2 is omitted and the electromagnet operates to close the shutter. Excess material in the tank may be removed by an air auxiliary pipe, a shutter in which operates through a lever connected to an electromagnet in series with the switch SH. A photo-electric or electrostatic relay operated by the balance beam may be used instead of the switch SL or SH. A feeding device or discharge means may comprise a valve.