Tray, assembly of cardboard blanks, and device and method for forming such a tray

A set of blanks to form a tray made of cardboard sheet material, wherein it comprises a first blank formed of a bottom having an external face connected by first fold lines to two first opposite side walls, each first side wall having an inner face, and at least a second blank capable of forming at least one of two second opposite side walls of said tray that are identical and symmetrical relative to a line of separation, each second side wall each comprising at least a first longitudinal flap connected on one side to a corresponding second wall by a second fold line and on the other side by said line of separation to the outer periphery of the other first longitudinal flap of the other second symmetrical side wall facing it, said first longitudinal flaps being arranged to be bonded to the external face of the bottom, the second fold line being offset to allow compensation of a thickness of corrugated board when the tray is formed, the side ends of the first longitudinal flaps bonded to the external face of the bottom of the tray are of a shape to match an upper surface of the tray or second longitudinal flap(s) in order to allow one to fit into the other when two trays are stacked on one another, and each second wall also comprising two sets of transverse flaps, said sets of transverse flaps each comprising at least one transverse flap suitable for being respectively bonded to a corresponding first side wall facing it when the tray is formed and wherein each set of transverse flaps comprises a first transverse flap connected to the corresponding second side wall by a third fold line and is capable of being bonded to the inner face of the adjacent first side wall.

A device for forming a tray from two blanks of cardboard sheet material or corrugated cardboard, namely a first blank formed of a bottom connected by first fold lines to two first opposite side walls and a second blank capable of forming two second opposite side walls of said tray, that are identical and symmetrical relative to a line of separation, each second side wall comprising at least one first longitudinal flap connected on one side to a corresponding second wall by a second fold line and on the other side by the said line of separation to the outer periphery of the other first longitudinal flap of the second symmetrical side wall facing it, the side ends of the first longitudinal flaps being of a shape to match an upper surface, once formed, of the tray or second longitudinal flap(s), in order to allow one to fit into the other when two trays are stacked on one another, and two sets of transverse flaps each comprising at least one transverse flap,

• wherein the device comprises
• two storage magazines for storing respectively the first and second blanks,
• means for cutting the second blank at the line of separation to form the two second opposite side walls,
• means for picking up and transferring the first blank from the storage magazine to an assembly station,
• means for firmly positioning the first blank in abutment in order to give it an exact reference position,
• means for picking up and transferring laterally by suction cups the second walls in order to place them on the first blank cut-out thus indexed,
• means for pasting the first longitudinal flaps and the inner face of the second walls and/or of the sets of second flaps during their transfer,
• means for pressing the first longitudinal flaps on the external face of the bottom of first blank,
• means for folding the sets of flaps toward the second walls,
• means for transferring the set of blanks thus constituted to a forming station, and forming means at said forming station for pressing the sets of transverse flaps on the corresponding inner face of the second walls such as the side ends of the first longitudinal flaps are of a shape to match the upper surface of the tray or the second longitudinal flap(s) in order to allow one to fit into the other when two trays are stacked on one another.

A method for forming a tray from two blanks of cardboard sheet material or corrugated cardboard, namely a first blank formed of a bottom connected by first fold lines to two first opposite side walls and a second blank capable of forming two second opposite side walls of said tray, identical and symmetrical relative to a line of separation, each second side wall each comprising at least one first longitudinal flap connected on one side to a corresponding second wall by a second fold line and on the other side by said line of separation to the outer periphery of the other first longitudinal flap of the second symmetrical side wall facing it, the side ends of the first longitudinal flaps bonded to the external face of the bottom of the tray are of a shape to match an upper surface of the tray or second longitudinal flap(s) in order to allow one to fit into the other when two trays are stacked on one another, and two sets of transverse flaps each comprising at least one transverse flap,

• wherein, after cutting the second blank at the line of separation to form the two second opposite side walls,
• the first blank is transferred to an assembly station,
• the first blank is firmly positioned in abutment in order to give it an exact reference position,
• the second walls are transferred laterally by suction cups while pasting the first longitudinal flaps and the inner face of the second walls and/or the sets of second flaps during their transfers,
• then they are placed on the first blank cut-out thus indexed,
• the first longitudinal flaps are pressed onto the external face of the bottom of the first blank,
• the sets of flaps are folded toward the second walls,
• and the set of blanks thus constituted is transferred to a forming station to form the tray said forming involving the step of pressing the sets of transverse flaps on the corresponding inner face of the second walls.