ES377670A1 - Improvements in bag filling machines - Google Patents

Abstract

An automatic machine for filling bags with fluent solid material comprises a rotatable tank 1 for the material, a number (only one shown in drawings) of combined filling and weighing units spaced round the tank and each having a bag supporting spout 14 which communicates through a conduit 19 with a tank outlet 3, means for controlling the passage of the material through the conduit 19, and a bag discharge mechanism, the arrangement being such that in the absence of a bag on the spout, or camoperated bar 23 which operates both the means for controlling the passage of the conduit 19 and the bag discharge mechanism, is inoperative. Each combined filling and weighing unit includes a beam 8 suspended from an end of a lever 7 fulcrumed on a bracket 5 fixed to the tank 1 and counterbalanced by weights, not shown, at the other end. The lower end of the beam is connected through a link 9 having pivot pins 10 and 11, to the tank bottom 2. The beam 8 carries the spout 14 pivotally mounted on a pin 16. When a bag 18 is positioned on the spout, a claw 17 pivotally mounted on the beam 8 is moved to rest tightly on the bag. At a predetermined angular position of the rotating tank a cam portion of a rail 26 lifts a roller follower 25 to fully open the conduit 19 which is flexible, so that material starts flowing into the bag. A predetermined weight of the material in the bag, aided by an additional initial load 34 at a pin 33, the beam moves downwardly to close the conduit. At a further angular position of the tank, a cam portion of a rail 32 acts on a roller 31 to relieve the beam of the load 34 so that the beam floats up and a pawl mechanism 37 on the beam lifts the conduit-controlling rod 24 to partially open the conduit for a secondstage filling. When the required weight of material is in the bag, the beam 8 again moves down to close the conduit. At a further tank position the roller rises further to engage a lever 28 so that a bar 23 which operates the conduit-control rod 21 swings by gravity into an inoperative position and then the beam 8 rises to lift the claw 17 to release the filling spout which, under the action of the filled bag, pivots downwardly about the shaft 10 and the bag shoots off. The bag cannot be discharged unless the bar 23 is in an inoperative position i.e. unless the conduit is closed. Also a safety device 36 actuated by the bag does not allow the conduit to open unless the bag is present. The initial operation of mounting the bags may be manual or automatic. Mechanical vibrators &c. may be provided to shake the bags during filling and air may be blown through the bottom of the tank to fluidize the material therein.