Patent GB-568147-A (GB)
Title: Improvements in apparatus for automatically weighing predetermined quantities of material
IPC: G01G13/02
Filed: 1943-03-03
Abstract: 568,147. Weighing-apparatus. STOCK, A. J. March 3, 1943, No. 3522. [Class 143] An apparatus for automatically weighing predetermined quantities of material comprises an enclosing framework with staggered top and bottom openings for the inlet and discharge of material, a conveyer within the enclosure for feeding the material to a weigh hopper situated above the discharge opening, an inclined baffle dividing the enclosure into two compartments one containing the conveyer and weigh hopper and the other containing the counterbalancing mechanism,' an horizontal tubular casing enclosing the weighbeam, and supporting means for the weigh hopper extending through the wall of the tubular casing. The conveyer may be moved bodily to one side of the inlet opening so as to allow the material to pass to the outlet opening without passing through the weigh hopper. As shown in Fig. 1, the apparatus is supported within a closed framework having an inlet i and outlet o. The material fed into the inlet is carried by a belt conveyer 27 to a weigh hopper 43 provided with a discharge gate 45 situated above the outlet o. The weigh hopper is suspended by links 53a from the two branches of a weighbeam 51, each branch being enclosed in a tubular casing 54 rendered dust-proof by a flexible bellows 49. The tubular casings communicate with a compartment containing a balance weight 60 which is suspended from the weighbeam by a cross-bar 58 and links 57. The belt conveyer 27 may be moved bodily, by a hand-lever 36 and links 37, 39, from the weighing position shown by full-lines to a non-weighing position shown by dotted lines. In the latter position, the material entering the inlet i falls on to an inclined baffle 91 and thence through the outlet o without passing through the weigh hopper. In operation, on closing a starting switch, a brake is released from a three-phase motor, a latch 69 is placed in locking engagement with the discharge gate mechanism, and the three-phase motor is started to drive the conveyer belt and thus feed the material to the weigh hopper. When sufficient material has been supplied to the weigh hopper, the consequent movement of the weigh beam opens a mercury switch thereby opening the starter contacts, stopping the motor, applying the brake, de-energizing a solenoid 72 to unlock the discharge gate mechanism and at the same time operating a counter. The unlocked discharge gate opens under pressure of the material and in doing so opens a mercury switch 78 to prevent re-starting of the three-phase motor before the discharge gate has been closed. A counterweight 67 on a bell-crank lever 64 tends to close the discharge gate to which it is connected by a link 62. In closing, the toggle action of the link 62 and arm 64 forces the gate into completely closed position. The material that dribbles from the conveyer belt when it comes to rest is compensated for by a weighted bell-crank lever acting upwards against the cross-bar 58. When it is desired to test the accuracy of the machine, a test switch is closed to maintain the energization of the solenoid 72, thus preventing the discharge gate 45 from opening, and allowing the balance of the weighbeam to be verified. Doors 92, 94, 95 permit access to the mechanism or withdrawal of the conveyer belt unit.