Patent GB-665027-A (GB)
Title: Improvements in bag-filling machinery
IPC: B65B1/22
Filed: 1949-06-24
Abstract: 665,027. Filling bags. MEDWAY PAPER SACKS, Ltd., and ROWLAND, F. A. Dec. 1, 1949. [June 24, 1949] No. 16818/49. Class 94(i). [Also in Groups 1 and XVIII] A machine for filling bags comprises electrically-controlled power means for clamping the bag to a filling spout, the clamping action being initiated by switch means actuated by the bag when presented to the spout. As shown, weighed charges of material are dumped from either of two scale pans 41 and 41a into a hopper 6 which is provided with a spout 7 integral with brackets 9 on which are pivoted a pair of clamping jaws 12 co-operating with spring-loaded pads 14. The jaws are coupled by toggle links 16 to a pair of levers 17 interconnected by bars 18 and 19 and fulcrummed on a hinge pin 11, the bar 19 being connected by a link 20 to the armature 21 of an electromagnet 22, the circuit of which includes switches S1 and S2 connected in series and operable by spring-loaded plungers 26 which carry plates 27 engageable by the mouth of the bag. The series connection of the switches ensures that the electromagnet is not energized unless the bag is presented squarely to the spout. During the opening of the jaws to clamp the bag the bar 18 engages a roller 35 on a lever 34 to effect closure of a locking switch 53 and safety switch S4 housed in boxes 33, whereby the electromagnet is maintained energized until a release switch is opened after a predetermined interval. The control circuit of the electromagnet is associated with that of a three phase, constant-speed motor 38 driving slappers 40 which are arranged to impact the sides of the bag during filling, and the movement of the clamping jaws is also arranged to cause the dumping of the contents of one of the scale pans into the hopper. The circuits include the switches S1-S4, a main switch S5 controlling the electromagnet 22, a release switch S6, a selector switch S7, starting switches S8 and S8a for the motor 38, switches S9 and S9a which are actuated by the scale beams 42 and 42a and control solenoids C3 and C3a operating the bottom doors 44 and 44a of the scale pans, a motor stop switch S10, a relay switch S11, a bag-release relay switch S12 and a main switch S13 in the circuit of motor 38. Certain switches are actuated by solenoids C1, C2, C4, C5 and C6, as shown in Fig. 3, and the connections are made across the phases P1 and P2 of the supply as indicated in Fig. 4. The armature of solenoid C1 is connected to levers 48 and 49 actuating the switches S5 and S7, the latter being arranged to select a circuit containing the switches S8 and S9 and the solenoid C3 or one containing the switches S8a and S9a and the solenoid C3a so that the scale pans are emptied alternatively. The solenoids C2 and C4 act on a lever 52 actuating the switches S11 and S12, a spring-loaded latch being provided to retain the lever in one of its operative positions. Assuming that both scale pans have been filled, thus closing switches S9 and S9a, and switch S7 is in the position shown, the raising of plungers 26 when a bag is applied to the spout closes switches S1 and S2 thus energizing solenoid C1 which closes switch S5 and moves switch S7 to its alternative position. The resulting movement of levers 17 closes switches S3 and S4 whereby the door 44a is opened to dump the charge in scale pan 41a. The subsequent closure of the door momentarily closes switch 58a to energize solenoid C2, and the lever 52 is thus rocked to position 52a to close switch S11. Solenoid C5 is thus energized to close switch S13 and start the motor 38 which runs until a cam 45 driven from the motor shaft momentarily closes the switch S10, thereby energizing solenoid C4 to move the bar to position 52b in which switch S11 is open and switch S12 closed. Solenoid C6 is thus energized to open switch S6, the switch S5 is opened by de-energization of solenoid C1 and the bag is released. When the next bag is presented to the spout, the sequence of operations is repeated except that the charge is dumped from scale pan 41.