Device for opening ends of tube pieces to open base squares, which consist of two superimposed walls • which at least comprises a transport device with which the tube piece may be conveyed in a horizontal position in a transport direction (x), which runs transversely to its direction of extension (z) • which comprises at least one means for opening the base square, which is movable in the direction of extension (z), and • with which the upper wall of one end of a tube piece may also be folded back to form an open base square, • wherein the at least one means for opening the base square is movable at least temporally simultaneously in the direction of transport (x) and in the direction of extension (z) of the tube piece, • wherein a first means for moving (22, 19, 19', 18, 17) is provided, with which the means for opening is movable - in the transport direction (x) of the tube piece or - in the transport direction (x) of the tube piece and in the direction of extension (z), • wherein the first means for moving (21, 16, 17) is rotably mounted on a lever arm (19, 19') which is rotatable about an axis of rotation (D 3) which is directed at right angles to the plane of the tube piece, and a further lever arm (19, 19') which is rotatable about a further axis of rotation (D 4) which is directed orthogonally to the plane of the tube piece, • wherein a second means for moving (21, 16, 17) is provided in the direction of extension of the tube piece and is movable by the first means for moving and carries the means for opening, and • wherein the second means for moving (16, 17, 21) comprise a coupling element and a drive with which the means for opening may be moved relative to the first means for moving (21, 16, 17), and • wherein both lever arms (19, 19') are connected via the coupling element, which is mounted rotatably in both lever arms characterized in that • the means for opening is mounted on a carriage, which is movable on the coupling element. • which at least comprises a transport device with which the tube piece may be conveyed in a horizontal position in a transport direction (x), which runs transversely to its direction of extension (z) • which comprises at least one means for opening the base square, which is movable in the direction of extension (z), and • with which the upper wall of one end of a tube piece may also be folded back to form an open base square, • wherein the at least one means for opening the base square is movable at least temporally simultaneously in the direction of transport (x) and in the direction of extension (z) of the tube piece, • wherein a first means for moving (22, 19, 19', 18, 17) is provided, with which the means for opening is movable - in the transport direction (x) of the tube piece or - in the transport direction (x) of the tube piece and in the direction of extension (z), - in the transport direction (x) of the tube piece or - in the transport direction (x) of the tube piece and in the direction of extension (z), • wherein the first means for moving (21, 16, 17) is rotably mounted on a lever arm (19, 19') which is rotatable about an axis of rotation (D 3) which is directed at right angles to the plane of the tube piece, and a further lever arm (19, 19') which is rotatable about a further axis of rotation (D 4) which is directed orthogonally to the plane of the tube piece, • wherein a second means for moving (21, 16, 17) is provided in the direction of extension of the tube piece and is movable by the first means for moving and carries the means for opening, and • wherein the second means for moving (16, 17, 21) comprise a coupling element and a drive with which the means for opening may be moved relative to the first means for moving (21, 16, 17), and • wherein both lever arms (19, 19') are connected via the coupling element, which is mounted rotatably in both lever arms • the means for opening is mounted on a carriage, which is movable on the coupling element.