Vacuum drum for a labeling unit, and labeling unit having a vacuum drum of this type

An apparatus comprising a drum for a labelling unit of a labelling machine for labeling containers, said drum being a vacuum drum that comprises a drum surface, said drum surface being a circumferential surface, a drum axis, and a vacuum-holder pair that rotates with said drum about said drum, wherein said vacuum-holder pair comprises front and rear holders provided at said surface and offset relative to one another along said rotation direction, said holders being vacuum holders, wherein said front and rear holders hold corresponding front and rear ends of a label as said label is held against said drum's surface, wherein each of said front and rear holders comprises a rotational switch that can be switched between two operating positions said rotational switch being a bistable switch comprising a switch actuator that causes said rotational switch to switch between said operating positions, wherein said rotational switch, after having been switched into an operating position, remains in said operating position, wherein, said rotational switch switches said front and rear vacuum holders between first and second operating positions, wherein said first operating position is a radially-inner position in which said pair is movable without contact past a gluer that is next to said drum, wherein said second operating position is a radially-outer position in which said vacuum holder pair enables said gluer to apply glue to said label, and wherein said switch actuator engages a stationary switch to initiate a switch between said operating positions.