Longitudinal folding device

A longitudinal folding device comprising:

• a machine frame;
• a longitudinal folding hopper supported by said machine frame, said longitudinal folding hopper having a hopper insertion plate and at least first and second hopper flank plates, said at least first and second hopper flank plates receiving paper webs electrically interlocked in a paper web train passing through said longitudinal folding hopper;
• a hopper guide device supported by said machine frame, said hopper guide device including an upper cover plate and left and right guide devices, said upper cover plate and said left and right guide devices being spaced from, and enclosing said hopper insertion plate and said first and second hopper flank plates of said longitudinal folding hopper;
• a high voltage source having different polarities, said different polarities being connected to said longitudinal folding hopper and to said hopper guide device, said different polarities connected to said longitudinal folding hopper and to said hopper guide device being matched to charges applied to adjacent webs of the electrically interlocked paper web train for supporting said paper web train between said longitudinal folding hopper and said hopper guide device;
• and
• electrically insulating means supporting said hopper guide device on said machine frame to electrically insulate said hopper guide device from said machine frame.