Patent GB-1296115-A (GB)
IPC: B65B9/02
Filed: 1970-05-13
Abstract: 1296115 Wrapping machines STEINER CO LAUSANNE SA 13 May 1970 [28 May 1969] 23283/70 Heading B8C In a machine for wrapping a roll 135 of towelling and comprising a feed platform 141 which urges the roll 135 against a reach of heatsealable film 200 to a position between a U- shaped heater 250 and a U-shaped sealing pad 230, to form an envelope 205 open at both ends and one side of the roll 135, the reach of film 200 is formed by inter-sealing at 204, two webs from upper and lower rolls 162, 182, and film is withdrawn from the upper roll 162 during envelope-formation, and is withdrawn from the lower roll 182 prior to sealing so that the seam 204 is displaced relative to the heater 250. Feed platform 141.-The platform 141 is pivoted on a pin 146 and has a slotted flange 147, in the slot 148 of which a bolt 153 carried by pivotal arm 150 is received. The arm 150 also carries a follower 152 abutting a cam 320 on a cam shaft 311. Film feed.-The upper roll 162 is supported on spaced knurled rubber wheels on a drive shaft 164 and knurled rubber wheels on an idler shaft 174, the lower roll being similarly supported. In an alternative embodiment (Figs. 19, 20) the upper roll 162 rests on two sets of knurled rubber wheels (778, 745) carried by idler shafts (774, 744), the idler shaft (744) being carried by swinging links (741) and co-operating with a drive shaft (764) carrying knurled rubber wheels (768). The film is tensioned by being passed over a U-shaped bracket 211 pivoted to the machine frame 110 and biased by a weight 214. Heater 250 and sealing pad 230 (Fig. 7).-The sealing pad 230 comprises a U-shaped baseplate 234 fixedly secured to the machine frame 110 and supporting two U-shaped foam rubber pads 235. Water passes through a cooling tube 240 situated between the pads 235. The heater 250 is carried by a pair of pivotable arms 290 having cam followers 295 which abut cams 330 on the main cam shaft 311. The heater 250 comprises a U-shaped can 254 from which depends an aluminium heat transfer base 255 which tapers to a knife edge 260 and contains an electric heating element 265 and a temperature sensor 266. A pair of U-shaped guides 270 for holding the film are also mounted on the cap 254, these guides being separated from the cap 254 by heat insulators 272 and carrying a cooling tube 280. A weight 267 is mounted on the top of the cap 254. Operation.-A roll 135 is fed to the feed platform 121 by an infeed conveyer comprising an endless belt (121, Fig. 2, not shown) and contacts a hinged upstanding plate 157 (Fig. 3) on the platform 141 to close a microswitch (375, Fig. 9, not shown) to activate a motor (315) to rotate the cam shaft 311 to pivot the feed actuator arm 130 and hence the platform 141. The roll 135 is thus urged against the film 200 and on to a shoot 305 between the heater 250 and the sealing pad 230. The urging of the roll 135 against the film 200 causes the film tensioning bracket 211 to pivot and thus close a microswitch (395) to activate a motor (177) to rotate the upper drive shaft 174 and supply film to form the envelope 205. As the cam shaft 311 and hence the cams 330 are rotated the U-shaped heater 250 is lowered by the weight 267 and the drive motor (197) for the lower film drive shaft 184 is activated to feed film from the lower supply roll 162 so that the transverse seal 204 in the film 200 is indexed about one inch from the position where the envelope 205 is to be sealed. With the heater 250 lowered onto the sealing pad 230 the guides 270 hold the film tautly across the trough between the rubber pads 235 and the knife edge 260 contacts the film to seal the envelope along a seam 207 and along two end seals 208 (see Fig. 16) and to reform the reach. The control mechanism is described in detail with reference to Fig. 9 (not shown). Completed package.-As shown in Fig. 16 the roll 135 is thus enclosed in a loose envelope 205 having a U-shaped seal 207, 208 with the legs 208 of the U interconnected by the seal 204. Excess film portions 221 may then be removed. The package then passes along the shoot 305 to a shrink tank (102, Fig. 1, not shown) where the envelope is shrunk to form the package shown in Fig. 18, the seams 504, 510, 507, 508 being equivalent to the seams 204, 207, 208.