Apparatus for clamping plates to external drum devices, based on movable clamps

Apparatus for clamping flexible plates of various sizes onto the cylindrical surface of a rotatable drum, comprising:

• a rotatable drum having a cylindrical surface;
• a plurality of grooves, cut into the surface of the drum;
• at least one clamp, each attached to the drum at one or more corresponding grooves and being switchable between two states—a clamping state and a released state;
• and
• at least one activation mechanism, not attached to the drum and including at least one member that is movable essentially radially to the cylindrical surface;
• wherein each of said clamps is fixed at any of a plurality of positions along the respective grooves and operative to clamp an edge of one of the plates, which crosses the respective grooves, to the surface of the drum, when in a clamping state, and is slidable along the respective groove, when in said released state,
• and wherein said at least one member of said at least one activation mechanism is operative:
• to engage any clamp, while said clamp is in an appropriate position,
• to switch said clamp to said released state, by moving radially inwards, and
• to switch said clamp to said clamping state, by moving radially outwards.