Patent GB-1010731-A (GB)
Title: Film-combining apparatus
IPC: B29C65/18
Filed: 1964-10-19
Abstract: 1,010,731. Seaming non-metallic sheet material. E. I. DU PONT DE NEMOURS & CO. Oct. 19, 1964 [Oct. 18, 1963], No. 42593/64. Heading B5K. [Also in Division F2] A film-combining apparatus comprises means 6, 7, 8 to hold a supply 9, 10, 11 of heat-sealable films 14, 15, 16 positioned so that the films have overlapping longitudinal edges; means 19 for heat-sealing these overlapping edges to form the films into a single continuous web 18; drive means 23 drawing the films 14, 15, 16 from the supply 9, 10, 11 and feeding the web 18 to a wrapping machine (not shown); and sensing means 58 responsive to irregular movements of the web 18 adapted to actuate the heat-sealing means 19 and the drive means 23 to control the heat-sealing and the feeding of the web 18 by the drive means 23. The film rolls 9, 10, 11 are held on mandrels 6, 7, 8 (see Division F2) each of which is unattached at one end. The web 14 passes over rolls 20, 56 and the webs 15, 16 pass directly over the roll 56 on to a heat-sealing table 17 covered with polytetrafluoroethylene coated glass fabric to prevent the films adhering thereto. The web 18 passes over a roll 57, between a pressure roll 22 and the drive roll 23 and is then pulled under the dancer roll 58 by the wrapping machine. The heat-sealing means 19 comprises units 46, 47 mounted on a rotatable bar 52 over the film overlapping edges. The bar 52 is actuated by an air cylinder 48 positioned by a solenoid valve 48a actuated by a switch 76 to raise and lower the units 46, 47. Each unit 46, 47 is pivotally suspended from an arm 51 on the bar 52 and comprises a conductive metal bar 49 containing a heater cartridge and a temperature control device (both not shown). A polytetrafluoroethylene coated glass fabric 50 covers the bottom of each unit 46, 47 and can be shifted, to allow for wear, by turning rollers 75 by a knob 75a (not shown). The distance between the units 46, 47 is adjusted by a hand wheel 55 and the units, as a whole, may be adjusted sideways by a hand wheel 55a. The drive roll 23 is a grooved rubber-covered roll driven by a motor 66 and has a comb tray 69 mounted thereunder, the tray 69 having fingers 70 extending into the grooves of the roll 23 to hold the web 18 in contact therewith. Springs 73, 74 urge the roll 22 into contact with the roll 23. The dancer roll 58 is freely rotated by the web 18 and has an internal shaft with gears 59, 60 at the ends thereof which gears move vertically in racks 61, 62. A lever arm 63 of switches 76, 77 is posited beneath the roll 58. In operation, when the apparatus produces excess film so that the roll 58 drops to its lowest position the roll 58 opens the switch 76 to break the circuit to the solenoid valve 48a which acts to lift the units 46, 47 off the film. The switch 76 also stops the motor 66. When the wrapping machine uses more film the roll 58 is raised to close the switch 76 to bring the units 46, 47 into contact with the film and to start the motor 66. The switch 77 is provided to operate a resistance in the motor control circuit to reduce the speed of the motor 66 but not to stop it. A three position toggle switch (not shown) may be provided and when it is placed in the automatic position the current travels through the switch 76. The manual position of the toggle switch is used in the initial film threading procedure. The centre position of the toggle switch deactivates the motor 66 and the solenoid valve 48a. Specified films sealed by this apparatus are films of regenerated cellulose having heatsealable coatings.