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A packing unit and method for folding a blank on a packing machine; the packing unit having: a packing conveyor having at least one pocket for receiving the blank; and a feed device for inserting the blank into the pocket on the packing conveyor; the packing conveyor has at least a first conveyor be

A packing unit and method for folding a blank on a packing machine; the packing unit having: a packing conveyor having at least one pocket for receiving the blank; and a feed device for inserting the blank into the pocket on the packing conveyor; the packing conveyor has at least a first conveyor belt defining a bottom wall, of the pocket; at least a second conveyor belt separate from, parallel to, and alongside the first conveyor belt, and defining the bottom wall of the pocket together with the first conveyor belt; a first retaining member, which projects perpendicularly from the first conveyor belt and defines a front wall of the pocket; and a second retaining member, which projects perpendicularly from the second conveyor belt and defines a rear wall of the pocket.

대표청구항 ▼

1. A packing unit (10) for folding a blank (4) on a packing machine (1); the packing unit (10) comprising: a packing conveyor (17) having at least one pocket (18) for receiving the blank (4); anda feed device (19) for inserting the blank (4) into the pocket (18) on the packing conveyor (17);wherein

1. A packing unit (10) for folding a blank (4) on a packing machine (1); the packing unit (10) comprising: a packing conveyor (17) having at least one pocket (18) for receiving the blank (4); anda feed device (19) for inserting the blank (4) into the pocket (18) on the packing conveyor (17);wherein the packing conveyor (17) comprises: at least a first conveyor belt (23), and at least a second conveyor be (24) separate from, parallel to, and alongside the first conveyor belt (23), said first and second (24) conveyor belts forming a bottom wall of the pocket (18); a first retaining member (25), which projects perpendicularly from the first conveyor belt (23) and forms a front wall of the pocket (18) in the direction of the packing path (P); and a second retaining member (26), which projects perpendicularly from the second conveyor belt and forms a rear wall of the pocket (18) in the direction of the packing path (P); andwherein the length (L) of said pocket (18) is a distance between said first retaining member (25) and said second retaining member (26) in the direction of the packing path (P)the packing unit (10) being characterized in that the feed device (19) comprises:a first suction pickup head (21), which engages a first panel (11) of the blank (4) inside a store (20);a second suction pickup head (22), which engages a second panel (13) of the blank (4) inside the store (20); andactuating devices (33, 34) for moving the pickup heads (21, 22) from a withdrawal position at the store (20) to a release position at the packing conveyor (17), to insert the blank (4) inside the pocket (18) on the packing conveyor (17), and then release the blank (4), folded into a ‘U’, inside the pocket (18) on the packing conveyor (17);wherein said length (L) is variable according to the format of said blank (4); andwherein said actuating devices (33, 34) alters the distance between said pickup heads (21, 22) and said packing unit at said store (20) according to the format of said blank (4). 2. A packing unit (10) as claimed in claim 1, wherein said packing conveyor (17) produces a relative movement between said first (23) and second (24) conveyor belts, to move said retaining members (25, 26) of said pocket (18) towards or away from each other according to the format of said blank (4). 3. A packing unit (10) as claimed in claim 1, wherein the packing conveyor (17) comprises a number of successive pockets (18), each bounded at the front by a corresponding first retaining member (25), and at the rear by a corresponding second retaining member (26); each first retaining member (25) only forms the front wall of a corresponding pocket (18); and each second retaining member (26) only defines the rear wall of a corresponding pocket (18); and said pockets (18) being spaced apart by a spacing distance (S) defined by the distance between said second retaining member (26) of a pocket (18) and said first retaining member (25) of the upstream pocket (18) in the direction of the packing path (P). 4. A packing unit (10) as claimed in claim 1, wherein the packing conveyor (17) comprises: two first conveyor belts (23) having respective first retaining members (25); andtwo second conveyor belts (24) having respective second retaining members (26) and alternating with the first conveyor belts (23). 5. A packing unit (10) as claimed in claim 4, wherein said two first conveyor belts (23) and said two second conveyor belts (24) are positioned side by side and parallel, and alternate with one another. 6. A packing unit (10) as claimed in claim 1, wherein: the first conveyor belt (23) is looped about respective first end pulleys (27, 28);the second conveyor belt is looped about respective second end pulleys (30, 31) parallel to and alongside the first end pulleys (27, 28); andthe first end pulleys (27, 28) can be operated out of phase with respect to the second end pulleys (30, 31) to adjust said length (L) of said pocket (18) according to the format of the blank (4). 7. A packing unit (10) as claimed in claim 6, wherein the packing conveyor (17) comprises: a first motor (29), which rotates a powered first end pulley (28); anda second motor (32), which is separate from and independent of the first motor (29), and rotates a powered second end pulley (31). 8. A packing unit (10) as claimed in claim 6, wherein the packing conveyor (17) comprises one motor (32), which rotates both a powered first end pulley (28) and a powered second end pulley (31). 9. A packing unit (10) as claimed in claim 8, wherein at least one powered end pulley (28; 31) can be operated mechanically out of phase with respect to the drive shaft of the motor (32) to adjust said length (L) of the pocket (18) according to the format of the blank (4). 10. A packing unit (10) as claimed in claim 1, wherein, as the pickup heads are moved from the withdrawal position to the release position, the actuating devices (33, 34) produce a relative movement between the first pickup head (21) and the second pickup head (22) to fold the blank (4) into a ‘U’ before the blank (4) is inserted into the pocket (18) on the packing conveyor (17); and as said pickup heads move from the withdrawal position to the release position, operation of said actuating devices (33, 34) is adjustable to adjust the movements of said pickup heads (21, 22) according co the format of said blank (4).