METHOD AND DEVICE FOR WELDING FOIL Russian patent published in 2001 - IPC

FIELD: welding foil; making foil bags. SUBSTANCE: welding device includes foil transportation unit and welding unit provided with welding head which may be placed in at least three functional positions: welding position for welding foil, intermediate position at which welding head is kept at first preset distance from welding position and nonworking position at which welding head is kept at second preset distance which exceeds first preset distance; welding unit includes additionally first pneumatic device with whose help welding head may be shifted between and intermediate positions and second pneumatic device with whose help welding head and first pneumatic device may be shifted between intermediate and nonworking positions; both pneumatic devices are connected in series. Method of welding foil consists in positioning the welding head on foil and moving it to first distance and then to second (larger) distance when welding procedure is discontinued; then welding procedure is discontinued; then welding head is shifted between welding position and intermediate position with the aid first pneumatic device, after which welding head and first pneumatic device are shifted between intermediate position and working position by means of second pneumatic device. EFFECT: enhanced efficiency; protection of foil against burning and damage; optimization of welding time. 10 cl, 5 dwg