Device for automatically unwinding web-shaped materials and method for operating such a device

A method for operating an unwinder for automatically unwinding a material web from a master roll, having an infeed arm and at least one first drive unit, wherein the master roll by way of a winding core thereof is rotatably mountable on the infeed arm, and by way of the drive unit a driving force is introducible into the master roll, wherein the unwinder has an outfeed arm to which at least one second drive unit for introducing a driving force into the master roll is assigned, wherein the master roll during an unwinding procedure is transferable from the infeed arm to the outfeed arm,

• wherein the material web is unwound from the master roll which is mounted on the infeed arm down to a predefinable minimum diameter, wherein during the ongoing unwinding procedure the master roll is subsequently transferred to the outfeed arm and thereon is further unwound, wherein a new master roll is received by the infeed arm, wherein an end of the material web that is unwound from the master roll which is mounted and driven on the outfeed arm is spliced to a lead end of the new master roll which is mounted and driven on the infeed arm, wherein to this end the material web emanating from the master roll which is mounted on the outfeed arm is pressed onto a circumference of the new master roll by a contact roller.