PURPOSE: To prevent the edges of a seal part on the inside of a container from heating to an unnecessary temperature by a method wherein two strip like magnetic substances are provided outside two straight parts extending along the full length thereof, projections are provided extending lengthwise of the straight parts at the four places thereof adapted to apply a high pressure and the projections are formed into an arcuate cross sectional contour.
CONSTITUTION: A pair of opposing pressing members 23 and 24 is fixed to the upper part of a pair of freely rockable arms 21 and 22 and the pressing member 24 is provided with a copper-made, U-shaped high frequency coil 27 having two straight parts 25 and 26 extending parallel to each other and with two strip-or plate-like ferrite-made magnetic substance 28. The projections 43 with arcuate cross section formed on the pressing surface 42 of the high frequency coil 27 press both edges of a tube with a high pressure upon sealing. The existence of the magnetic substance 28 on the outside of the coil 27 causes the magnetic line of force attempting to diffuse outwardly of the coil 27 to refract in the direction of the magnetic substance 28. For this reason, the parts of packaging material outside of the coil 27 become difficult to heat.
IWANO FUMIYUKI
NISHIGUCHI YOICHI
TAKAHASHI HISAO
OGAWA MASAAKI
KOBASHI YOSHIO
JUJO PAPER CO LTD
| JPS6252025A | 1987-03-06 | |||
| JPS48107336U | 1973-12-12 | |||
| JPS63299072A | 1988-12-06 | |||
| JPH0242055A | 1990-02-13 |
| US3078201A | 1963-02-19 |