The present invention is intended to effect proper sealing of a film by automatically adjusting the gripping pressure exerted by seal bars on the basis of a change in unsteady current flowing through the seal bars which grip the film. When the main shaft of a servomotor mounted on a frame is rotated...http://www.google.com/patents/US5653085?utm_source=gb-gplus-sharePatent US5653085 - Sealing device for packaging machine
