Patent GB-694481-A (GB)
Title: Improvements in or relating to bag filling machines
IPC: B65B1/18
Filed: 1946-08-13
Abstract: 694,481. Filling bags. ST. REGIS PAPER CO. Aug. 13, 1946 [Aug 23, 1945], No. 23976/46. Class 94(i). [Also in Group XVIII] An automatic-feed weigher is adapted for filling valve bags through two filling nozzles alternately, and comprises a feed hopper with dump and dribble outlets closed in succession by weighing movement, together with control means responsive to weighing movement for successively discharging the weighing receptacle, opening the dump outlet and actuating a deflector to switch the next weighment to the other nozzle. In the embodiment shown a continuous stream of material enters through a hopper A, and successive weighments made by a receptacle D on a weighing scale E are delivered to a pair of side-by-side valve-bag nozzles 241 alternately. The bags are secured manually to the nozzles by clamps I and the machine continues functioning automatically as long as the clamps are operated and bags are present to receive the charges. The filled bags are released from the nozzles automatically, held temporarily on a trap-door to enable the operator to close them and then fall through to a discharge shoot. Feed to weighing receptacles. The feed hopper C is supplied continuously from the inlet hopper A by means of a worm 52, two bulk stream nozzles 72 (Fig. 4) delivering to either side of the hopper and a dribble stream nozzle 71 delivering to a dribble feed hopper 67 located within the main hopper C. Discharge of the hopper into the weighing receptacle is by way of a pair of bulk gates 75, 76, which are interconnected so as to swing open together on pivots 79, and a sliding dribble gate 100. When the gates are first opened the material accumulated in the main hopper is dumped into the weighing receptacle whereafter the weight is made up with the bulk gates closing in advance of the dribble gate which effects the final cut-off. Weighing scales. The weighing receptacle D is suspended by knife-edges 135 (Fig. 10) on a pair of spaced weigh-beam members 120 fulcrummed on knife-edge bearings 124. The weigh-beam has a main counterweight 129 with auxiliary weights 131 at either side and an adjustable weight 132 for exact setting. A pivoted locking member 174 holds the beam against movement whilst the initial part of the charge is being dumped into the receptacle. A spring 169 initially engages a bracket 149 on the counterweight 131 partially to off-set it until the dribble feed commences, the bracket 149 then having moved out of range of a roller 165 through which the spring acts. Feed-gate opening and tripping mechanism. Opening and closing of the bulk and dribble feed gates is effected by rods 86 and 108 respectively. Levers 140, 155 (Fig. 10) are connected to these rods and are operable by a motor-driven cam a to open the gates which are then held open by latches 145, 160 engaging over the levers. As the weighing receptacle sinks as the final weight is approached, trip screws 148, 163 on the bracket 149 depending from the counterweight 131 release the latches 145, 160 in succession so that first the bulk gates and finally the dribble gate are released and close. Discharge of weighing receptacle; bag filling arrangements. The weighing receptacle has a pair of discharge gates 178, 179 (Fig. 4) which open downwardly on pivots 182 but are normally held closed by a rod 186 pivoted at 187 (Fig. 2) to a weighted locking member 188 pivoted at 189. The rod bears against the edge of the locking member under the weight of the discharge gates, its line of centres lying to the left (Fig. 2) of the point of contact. Opening of the gates is effected by a second motor-driven cam b (Fig. 10) which rocks a lever 198 causing a finger 193 on a connected bell-crank 194 to knock the locking member 188 over clockwise (Fig. 2) so that the gates fall open under the weight of material. A spring 201 later returns the finger 193 which knocks the locking member 188 back and closes the gates then unloaded. Successive weighments discharged from the weighing receptacle are directed by a deflector 226, which is rocked to and fro on a pivot 220 at each cycle of the machine, into a pair of side-by-side bag filling hoppers H alternately. Each of these hoppers terminates in a bag-filling nozzle 241 (Fig. 14) through which the material is discharged by means of a screw 243. The gripping member 261 of each bag clamp I is depressed to grip the bag mouth by manually raising a lever 253 to the position shown where it is held by a locking catch 256, the body of the bag resting on a chair 290 (Fig. 1) pivotally mounted at 296 and locked in the position shown by a catch 309. Filled bags are released under the control of a further motordriven cam which, through links and levers 278, 277, 274, 272, 271, 270 and 266 releases and restores the clamp lever 253, whilst the lever 272 moves forward a bag pushing member 331 and, through a sliding abutment 325, trips the bag chair catch 309 so that the bag falls clear of the chair and nozzle and on to the trap-door (not shown) which finally releases it to a discharge shoot beneath. The bag chair is vibrated on leaf springs 300 during the filling. Operating mechanism. Power for the machine is supplied by a motor 400 through belt gearing. The several control cams referred to are mounted on a pair of intergeared shafts in a control housing 113 (Fig. 1) driven by the motor the drive being through a one revolution clutch which is engaged, to initiate the next cycle as each is completed, by the movement of the rod 108 which closes the dribble feed gate. If, however, an empty bag is not in position on the appropriate nozzle, mechanism indicated at 450 (Fig. 1) and controlled by the bag clamp operating link 278, comes into operation to prevent the clutch engaging. A clutch 54 in the drive to the feed screw 52 is also disengaged so that the machine ceases operation. It is then necessary to operate a starting handle 487 after clamping an empty bag to the vacant nozzle. An emergency stopbutton 477 enables the clutch 54 to be disengaged to stop the feed when required. Counting devices. A counter 236 (Fig. 2) is stepped-up each time the deflector plate 226 is thrown over and records the number of weighments made.