Patent GB-645802-A (GB)
Title: Packaging machine
IPC: B65B31/06
Filed: 1948-10-18
Abstract: 645,802. Evacuating and sealing filled bags. DEWEY & ALMY CHEMICAL CO. Oct. 18, 1948, No. 27060. Convention date, Nov. 26, 1947. [Class 94(i)] A machine for evacuating and sealing a filled bag of heat - sealable material comprises a pair of opposed sealing jaws, a movable evacuating nozzle or tube which may be so positioned as to extend through the neck of the bag between the jaws, and means for withdrawing the nozzle simultaneously with the closing of the jaws on to the neck of the bag. The machine shown comprises a stationary jaw 4 supported on the upper surface 2 of a main frame 1, and a movable jaw 5 carried by a vertically reciprocable frame, the lower cross member 17 of which is connected to the rod 19 of a piston 18a working in an air cylinder 18. The bag B is supported in a detachable trough 20a with its neck extending between the jaws and its mouth fitting over an evacuating nozzle 21 which is detachably mounted in a sleeve 22 carried by a plate 22a slidably mounted on the surface 2. Troughs and nozzles of varying size may be fitted to suit different sizes of bag. The front end of the nozzle is formed with slots 21a and is lined with perforated sheet metal to prevent the collapsed folds of the bag material passing through the slots. A rod 24, having a bore communicating with the interior of the nozzle, is movable axially within the nozzle by means of a lever 25 coupled by links 27, 28 to the cross member 17, this lever being pivoted at an intermediate point to a lever 29 fulcrummed on a bracket 26 and coupled at its upper end to the plate 22a. The vacuum connection 23 to the nozzle comprises a valve 23a which is normally held closed by a spring 30 but may be opened by depression of a treadle 32 coupled by linkage to the valveoperating lever. The jaw 5 is normally maintained in a raised position by a catch 35 which may be released by energizing an electromagnet 37 connected in parallel with a second electromagnet 38 in a common control circuit which includes pressbutton switches 42, 43 on either side of the frame 1. The magnet 38 controls the exhaust and supply connections to the upper and lower ends of the cylinder 18, so that on depression of both buttons the jaw 5 moves downwardly and the linkage 27, 28 is operated to effect withdrawal of the tube 24 and a movement of the nozzle 21 to the left to relieve the tension on the bag neck during the sealing operation. As the jaw 5 approaches the jaw 4, a finger 41 on the cross-member 17 operates an exhaust valve 40 to slow down the movement of the jaw, and as. the jaws come together a finger 46 closes a switch 45 to short Circuit the press-button. 42, thus freeing the operator's right hand to enable him to tear off the outer portion of the neck of the bag extending beyond the sealing jaws. The jaw 5, Fig. 4, is mounted on a member 5a formed with bores 5c and 5d housing an electric heater and a thermostat respectively, and is provided with a movable guard 5e which is raised clear of the bag, when the jaw is lowered, by the engagement of feet 33a and 34a with the surface 2. The jaw 4 comprises a member 4a, formed with bores 4b and 4c for the reception of an electric heater and thermostat, to which is secured a strip of resilient, heat-resistant material 4d. Alternatively, the jaws may be formed as electrodes to which a high-frequency voltage is applied.