GB1370809A - Method of and apparatus for vacuum packaging - Google Patents

Abstract

1370809 Packaging machines W R GRACE & CO 10 Dec 1971 [14 Dec 1970] 57522/71 Heading B8C In a packaging machine, a bag 56 containing an article, e.g. a fowl 61, is evacuated in a vacuum chamber 39 part of the wall of which comprises a diaphragm 24 which, on evacuation of the chamber 39, distends into the chamber to engage the bagged fowl 61 to expel air from the bag 56 and to shape the fowl 61. The diaphragm 24 is carried by a hood (12, Fig. 1) lowered by piston and cylinder assemblies 19, 20 on to an endless conveyer 13 to form the chamber 39. The diaphragm 24 also forms one wall of a second chamber 25 connected to the chamber 39 by a restricted bleed line 27 containing a valve 28 which can be adjusted to control the pressure difference between the chambers 25, 39. Bag supports 15 are carried by the conveyer 13 and have slotted end pieces 117, 118 which receive the gathered neck 54 of the bag. In operation, a striker 10 carried on the support 15 engages a switch 23 which operates a valve 40 to vent the cylinders 20 so that the hood (12) slowly drops. The striker 10 then engages a second switch 41 to engage a brake 100 and disengage a clutch 31 connecting a drive motor 30 to the conveyer 13. The conveyer 13 thus stops so that two supports 15 are below the descending hood (12). As the hood descends an actuator 35 thereon engages a switch 42 to deenergize the motor 30, and when fully descended an actuator 36 engages a switch 45 so that a valve 46 in a line 16 is opened so as to evacuate the chamber 39 via a manifold 37 and an opening 21 in the conveyer 13. When the pressure in the chamber 39 drops to a predetermined level, a switch 48 causes a valve 51 to connect an assembly 11 to a compressed air line 52 so that the assembly 11 operates to place a clip around the bag neck 54. When the pressure in the assembly 11 reaches a predetermined value (indicating that the clip has been applied), a switch 57 causes the valve 51 to connect the assembly 11 to a vacuum line 26, and the valve 46 to vent the chamber 39. On the chamber 39 reaching atmospheric pressure, a switch 49 causes the valve 40 to connect the cylinders 19 to a pressure source to raise the hood (11). This thus raising causing the switch 42 to re-energize the motor 30 and a switch 60 to disengage the brake 100 and engage the clutch 31. The assembly 11 is carried by the hood and comprises a punch 62 connected to a piston 61 acted on by the pressure in a chamber 120 connected to the valve 51. A pivotable arm 71 carries an anvil 63 for closing the clip about a bag neck. As the hood is lowered, the neck 54 of the bag enters a slot 66 in the assembly 11 and a reciprocable rod 33 engages a stop 55 on the conveyer 13 to cause the arm 71 to pivot and close the end of the slot 66. When the hood is reused a spring 70 extends the rod 33 and thus pivots the arm 71 to open the end of the slot 66. Clips 72, are supplied to the slot 66 from a cylinder (80, Figs. 6 and 7) via a channel member (85). Alternatively (Fig. 9) the arm 71 is pivoted by a cylinder (121).