Zig-zag folding machines

Claim 1

A Zig-Zag folding machine (1 or 2), for the concertina-like folding of pliable strip material (3), comprising: folder means having first and second parts (4 and 5); first and second spaced folding rollers (6 and 7) rotatable about parallel axes and respectively cooperable with the first and second parts (4 and 5) of the folder means to form first and second folding devices (4, 6 and 5, 7); non-return feed means (8 and 9 or 10) which prevent return movement of pliable strip material (3) fed between the first and second spaced folding rollers (6 and 7); drive means (11) operable to drive the first and second rollers (6 and 7), directly or indirectly, alternately both in one direction and then both in the opposite direction; and movable guide means (12 or 13) for directing the pliable strip material (3) towards at least one of the spaced folding devices (4, 6 and 5, 7); characterized in that: the first and second parts of the folder means comprise third and fourth folding rollers (4 and 5); the folder means include an intermediate part (14) extending between the third and fourth folding rollers (4 and 5); and the movable guide means (12 or 13) are mounted between the third and fourth folding rollers (4 and 5) for movement relative to the intermediate part (14) of the folder means by turning about an axis extending parallel to the axes of the first and second folding rollers (6 and 7) and disposed on the side of the intermediate part (14) opposite to the non-return feed means (8 and 9 or 10).