first terminal position into the second terminal position operates directly on the disk 30 e g by means of a gearwheel so that it does not have to be rotated with roller pair w9 w10 the lower roller w10 is driven by the motor m3 though here a drive for the upper roller w9 is also possible at this point discussion is directed to the two cylinders r1 and r2 fig6 and 7 which prevent buckling of the strip f across the direction of transport cylinder r1 is positioned in an elongated hole 31 provided in the flange of guide plate l3 while cylinder r2 is immovably mounted in the first position of disk 30 in which the strip f is not introduced into the turning channel 2 the cylinder r2 prevents buckling of the strip f in the upward direction fig6 the cylinder r1 plays no role when the disk 30 is in this position when the disk 30 is rotated into the position in which the strip is fed into the turning channel 2 however cylinder r1 slides within the elongated hole to the lower end of said hole with the result that it is the cylinder r1 that prevents upward buckling of the strip f in the given position of disk 30 and not the cylinder r2 as in the other disk position fig6 in the position of the disk 30 shown in fig7 the cylinder r2 serves as a deflector for the transport of the strip f into and out of the turning channel 2 when the strip f being processed leaves.