GB726557A - Improvements in or relating to method of and machine for packaging commodities - Google Patents

Abstract

726,557. Packaging. MARATHON CORPORATION. Feb. 10, 1953, No. 3691/53. Class 94 (1). A method of packaging commodities, e.g. cheese, in flexible heat-activatible material 16, Fig. 12, comprises forming a commodity-filled package completely sealed except for a folded, unsealed portion 23 having superposed plies of the material,.the extremity providing an opening at 24 leading to the interior of the package, clamping the portion 23 except at a selected area to form a gas-tight seal thereabout, applying a vacuum to the outer surfaces of the portion 23 at the selected area to separate the plies to form a channel leading into the package, and applying a vacuum to the channel to evacuate the package. The package is finally heat-sealed at the area 25. In practice, eared portions 23 at each end of the package are dealt with simultaneously by the above method. A machine for carrying out the method operates as follows. The package is supported on a plate 30 between blocks 33, the ears 23 resting on rubber clamping members 35 on the blocks 33. Rotation of a shaft 61 acts through cams 62 and followers 65 to lower bars 66 against springs 39 and bring jaws 36 having rubber clamping members 37 into engagement with the tops of the ears 23 which are hence clamped. Further rotation of the shaft 61 causes a cam 64 to permit a spring-actuated plunger 80, Fig. 10, to move left and put a vacuum tank 50 and pipe 84 into communication with openings 42, 43, in the blocks 33, and an opening 45 in the jaws 36. The openings 42, 43, 45 lie in grooves in their respective clamping members 35, 37, the grooves coinciding to form a channel when members 35, 37 are in engagement. The vacuum applied to the openings 42, 45 pulls. out the plies of the ears 23 to form a channel leading into the package, through which vacuum applied via the openings 43 evacuates the package. Further rotation of the shaft 61 acts through a cam 63 to depress a lever 75 against a spring 182 and lower a rod 74 to rotate a shaft 70 which carries bars 47 having sealing surfaces 48 adapted to engage the upper edges of plates 34 carried by the blocks 33. The bars 47 are. heated during "rest" periods by conduction from an electrically heated block 49 which they contact. The bars 47 are resiliently mounted at 73 on arms 71 integral with collars 72 rotatable on the shaft 70.which is pinned at 177, Fig. 16, to a collar 78<SP>1</SP> connected through an arm with the rod 74. Rotation of the shaft 70 moves a pin 176 fixed thereto and lying in a slot 175 in the collar 72, to permit the collar 72 to be rotated by a spring 171 fixed at 173 to bring the bars 47 down and heat-seal the package. The cams 62, 63, 64 are so arranged that further rotation raises the bars 47, cuts off the vacuum and opens the clamp 35; 37. Residual vacuum in the system is bled off at 86, Fig. 10. In a modification, Fig. 18 the heat-sealing device described is replaced by a vertically reciprocable head H mounted on a plate 219 which is vertically movable on rotation of the shaft 61 through eccentrics thereon and a suitable linkage. The head H comprises a metal block 230 having electric heating elements 243 and recesses 231 in which are spring-pressed sealing bars 236. Each bar 236 has a narrow part 237 channelled at 237<SP>1</SP> a pin 241 working in a vertical slot in each bar 236 limiting upward movement of the bar which is held by a plate 232 against downward movement. In a further modification, Figs. 20, 21 (not shown), separate vacuum sources are used for the openings 42, 45 on the one hand, and for the opening 43 on the other, the latter having a lower vacuum supply than the former. The method according to the invention is also described with reference to sealing the neck of a package, Fig. 22 (not shown). In this case the clamping surfaces are vertical, and they and the sealing bars move horizontally, and the packages are delivered by a conveyer but otherwise the operation of the device is as above.