A vacuum drum assembly for handling labels cut from a web-like labelling material in an automated labelling process, comprising:
- a vacuum drum;
- and
- a distributor device, the vacuum drum being mounted, in a rotatable manner about a central axis, on the distributor device,
- wherein:
- the distributor device includes first air passages in fluid communication with a vacuum source;
- the vacuum drum includes second air passages extending to a plurality of ports formed in an outer lateral surface of the vacuum drum for receiving and retaining strips of the labelling material, the second air passages being configured to communicate with the first air passages at predetermined angular positions of the vacuum drum as the vacuum drum rotates about the axis, so that the strips of the labelling material are retained by the vacuum drum along a circular label path between an input station and an application station arranged at a first angular distance from the input station with respect to the axis, and so that the strips of the labelling material are released at the application station;
- the distributor device includes a switching device configured to selectively switch between a first operative configuration where the fluid communication between the first air passages and the vacuum source is established over the first angular distance, and a second operative configuration where the fluid communication between the first air passages and the second air passages is established over a second angular distance greater than the first angular distance;
- and
- the switching device includes a block component housed in one of the first air passages at the first angular distance from the input station, with respect to the axis, the block component defining, in the one of the first air passages:
- a first chamber upstream of the block component, with respect to a direction of advancement of the strips of the labelling material along the circular label path;
- and
- a second chamber downstream of the block component, and
- wherein the block component is selectively movable between:
- a first position, where the block component cooperates in an air-tight fashion with a bottom surface of the vacuum drum, such that the first and second chambers are not in fluid communication, and only the first chamber is in fluid communication with the vacuum source;
- and
- a second position, where the block component is moved, such that the first and second chambers are in fluid communication with each other and in fluid communication with the vacuum source.