Method and apparatus for positioning a welding jaw

Method for positioning a welding jaw during a welding operation, in particular a welding jaw of a transverse sealing station of a vertical tubular bag machine, the welding jaw being moved in a circulating manner along a closed path or back and forth along a linear path, to be set against a resistance, in particular a second, oppositely running welding jaw, two layers of film lying one on top of the other, with a total thickness (d) for both layers of film together, of a film tube being pressed together between the resistance and the sealing surface of the welding jaw, in particular between the sealing surfaces of two welding jaws, in order to weld the film tube by means of heat introduced into the film tube via the sealing surface of the welding jaw or the sealing surfaces of the welding jaws, with an exerted pressure in a sealing plane (S) under a sealing force within a sealing time, and a drive being provided for the purpose of moving the welding jaw in a direction normal to a surface of the resistance or an oppositely running welding jaw, in order in this way to carry out the welding operation in a fixed location or along a sealing path within the sealing time, wherein a distance (a) between the sealing surface and the resistance or between the two sealing surfaces of the welding jaws during the welding operation is prescribed by a control device of the drive, and in that the value for the distance (a) is always less than or equal to the value for the thickness (d) for the two layers of film lying one on top of the other.