Patent GB-881776-A (GB)
Title: Bag filling machine
Inventor: LAU ERWIN MARTIN
IPC: B65B1/18
Filed: 1959-05-07
Abstract: 881,776. Bag filling and weighing apparatus. BLACK PRODUCTS CO. May 7, 1959, No. 15726/59. Class 143. Apparatus for filling bags 25 with a predetermined weight of granular, flaky or powdered material comprises a conditioning chamber 21 from which the material is fed, by a fluidizing flow of air entering the chamber through a diffuser pad 27 located near to the material outlet 31, horizontally through a flexible tube 32 connecting said outlet 31 with a bag filling and supporting spout 24, the spout 24 being supported by a weighing scale 22 which is responsive to a predetermined weight of material in the bag to close a pinch valve 29 controlling the flexible tube 32 and to close an air valve 94 controlling the supply of fluidizing air to the chamber 21. As shown the conditioning chamber 21 is supplied with material by a hopper 121 through a pneumatically operated double pinch valve 120, Fig. 1, and the outlet 31, Fig. 6, is positioned at the lower end of the front vertical wall 30 of the chamber. The diffuser pad 27, which may comprise three-ply canvas belting, slopes upwardly away from the base of the outlet 31 and is bounded by the front and side vertical walls 30, 105 defining the trapezoidal cross-section of the chamber. The pinch valve 42 is carried by abracket 35 which is bolted between the front wall 30 and a frame plate 38 and serves to clamp the flexible tube 32 in position, and the valve comprises a rod 41 movable by a pneumatic cylinder 42 to squeeze the tube against a fixed rod 40. The spout 24 connects with a front extension 44 of the tube and is carried by a crossmember 54, Figs. 6, 7 and 9, of a floating frame 23 which is supported for limited vertical movement on the fixed framework 20. The weighing scale comprises a beam 60 weighted on one side of a fulcrum 67 by an adjustable counterweight 146 and supporting on the other side the floating frame 23. The beam 60 is in the form of a rectangular frame the side members 61 of which carry notched fulcrum blocks 63 for bearing engagement with aligned conically edged fulcrum discs 67 journalled between fixed cross-beams 66. The floating frame 23 bears on the side-members 61 through similar discs 65, Fig. 7, located between arcuate-based V-section notches in blocks 62, 64 secured respectively to the members 61 and to vertical side rails 53 of the frame 23. The vertical rails 53 carry the crossmember 54 and are each supported between a pair of fixed guide rails 52 by upper and lower pairs of conically-edged spacer discs 56 engaged between facing arcuate V-sectioned notches 55 in the rails 53, 52, Fig. 10. The notches 55 have a 90 degrees angle and the spacer edges have a 60 degrees angle. The frame 23 is covered by a fixed shroud 58 which supports a pneumatically operated bag clamp 130. In operation, with a bag 25 applied on the spout 24, a push button 92 is operated to close an electric circuit through a holding relay 93, Fig. 14, and a normally closed micro-switch 87 to a series of solenoid-operated air valves 86, 94, 125 and 133. The valve 86 is thereby operated to disconnect a flap valve 83, feeding the pinch valve cylinder 42 from the air supply line 88 and to connect it to an exhaust line 86a whereupon the flap of valve 83 springs over to allow the cylinder 42 to exhaust via a line 77 which feeds, via manifolds 70, 71, and 72, and pipes 80, a series of cleaning air jets directed at each the spacer, bearing and fulcrum discs 56, 65 and 67, the exhausted cylinder 42 thereby permitting the pinch valve to open for feed of material into the bag 25. The valve 94 is simultaneously operated to permit supply of air from the line 88, if necessary through a regulating valve (not shown), to the diffuser pad 27 and thereby effect fluidized feed of material through the spout 24. The valve 125 is included for use with flaky materials and serves, when energized, to permit air supply to the hopper feed pinch valve 12 to close same and thereby decrease the upward escape of fluidizing air. The energized valve 133 effects pneumatic operation of the bag clamp 130. When the bag is filled to the predetermined weight, the weigh beam 60 is tilted to open the microswitch 87 to de-energize the valves 86, 94, 125 and 133 thereby closing the pinch valve 42, stopping the fluidizing air supply, opening the hopper feed valve 120 and releasing the bag clamp 133. A manual air valve 140 is provided for supply of air of spout cleaning jets 142. In a modified arrangement wherein the spacer, bearing and fulcrum discs are subjected to cleaning air blasts at the end of a weighing cycle, and not at the beginning as above, the fluidizing air is fed via a flap valve, an air reservoir, and a regulating valve so that, on closing of the fluidizing air supply, the reservoir is exhausted to the cleaning air jets.