Method and machine for forming flexible bags with special bottom
AssigneeHolweg Group
InventorsVincent Schalck, Thomas Fichtner
Life of this patent
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Abstract
A flexible bag comprising a first wall and a second wall superposed over the first wall, the walls being connected to each other along their longitudinal edges by two gussets. As per a bag formation process, successively: the bag is closed with a flap extending from one of the walls and held on the other wall to form a closed end of the bag; the first wall of the bag is gripped at a predetermined distance from the closed end with the lower grippers and the second wall by the upper grippers and the walls are separated to form a side on the gussets; the second wall is released by the upper grippers and the closed end is folded by a folding device on to the second wall, thus making the bottom.
Claims20
A process for forming flexible bags, each bag comprising a first wall and a second wall superposed over the first wall, the first and second walls being connected to each other along respective longitudinal edges thereof by two gussets, whereby successively:
- the bag is closed to form a closed end of the bag opposite to an open end;
- at a predetermined distance from the closed end of the bag the first wall is gripped by lower grippers mounted on a lower support and the second wall is gripped by upper grippers mounted on an upper support and the first and second walls are separated by way of the lower and upper grippers;
- the second wall is released by the upper grippers and the closed end is folded by a folding device on to the second wall forming a first crease extending on to the first wall between the lower grippers, a second crease extending on to the second wall and a third crease entering into the second wall symmetrically with the closed end of the bag with respect to the second crease, thus forming a bottom delimited between the first and second creases;
- wherein the lower and upper grippers are separated, a side is formed on each of the two gussets extending from the first wall to the second wall, and wherein the second crease extends on to the second wall between the respective sides of the two gussets, and
- wherein a separation is maintained between the second wall and the first wall over at least part of a width of the bag and over an entire length of the bag in order to create a channel to supply air from the open end to the closed end.
A machine for manufacturing flexible bags, the bag comprising a first wall and a second wall superposed over the first wall, the first and second walls being connected to each other along respective longitudinal edges thereof by two gussets, one end of the bag being closed, the machine comprising:
- a reception system for receiving a series of bags moving in a main direction parallel to the longitudinal edges, with the closed end leading;
- a lower support for supporting two lower grippers, the lower grippers being arranged to grip the first wall at a predetermined distance from the closed end of the bag;
- an upper support for supporting upper grippers, the upper grippers being arranged to grip the second wall at a predetermined distance from the closed end of the bag, the upper support and the lower support being arranged to separate the lower grippers from the upper grippers to form a side on each of the two gussets extending from the first wall to the second wall, and
- a folding device to fold a bottom on to the second wall by forming a first crease extending on to the first wall between the lower grippers, a second crease extending on to the second wall between ends of the sides, and a third crease entering on to the second wall symmetrically at the closed end of the bag with respect to the second crease,
- wherein the folding device is made by a folding cylinder configured to squeeze the bag against the lower support, and
- wherein the lower support and/or the upper support comprise(s) a suction system to suck respectively the first and/or second wall(s) so as to separate said first and/or second wall(s) before being gripped by the lower and upper grippers.
A process for forming flexible bags, each bag comprising a first wall and a second wall superposed over the first wall, the first and second walls being connected to each other along respective longitudinal edges thereof by two gussets, whereby successively:
- the bag is closed to form a closed end of the bag opposite to an open end;
- at a predetermined distance from the closed end of the bag the first wall is gripped by lower grippers mounted on a lower support and the second wall is gripped by upper grippers mounted on an upper support and the first and second walls are separated by way of the lower and upper grippers;
- the second wall is released by the upper grippers and the closed end is folded by a folding device on to the second wall forming a first crease extending on to the first wall between the lower grippers, a second crease extending on to the second wall, and a third crease entering into the second wall symmetrically with the closed end of the bag with respect to the second crease, thus forming a bottom delimited between the first and second creases;
- wherein when the lower and upper grippers are separated, a side is formed on each of the two gussets extending from the first wall to the second wall, and wherein the second crease extends on to the second wall between the respective sides of the two gussets, and
- wherein bags closed by a flap are formed initially, and stacked and then unstacked to make the bottom.
A machine for manufacturing flexible bags, the bag comprising a first wall and a second wall superposed over the first wall, the first and second walls being connected to each other along respective longitudinal edges thereof by two gussets, one end of the bag being closed, the machine comprising:
- a reception system for receiving a series of bags moving in a main direction parallel to the longitudinal edges, with the closed end leading;
- a lower support for supporting two lower grippers, the lower grippers being arranged to grip the first wall at a predetermined distance from the closed end of the bag;
- an upper support for supporting upper grippers, the upper grippers being arranged to grip the second wall at a predetermined distance from the closed end of the bag, the upper support and the lower support being arranged to separate the lower grippers from the upper grippers to form a side on each of the two gussets extending from the first wall to the second wall, and the lower and upper supports are respectively lower and upper contrarotating cylinders;
- a folding device to fold a bottom on to the second wall by forming a first crease extending on to the first wall between the lower grippers, a second crease extending on to the second wall between ends of the sides, and a third crease entering on to the second wall symmetrically at the closed end of the bag with respect to the second crease;
- and
- a pressing system for pressing on the second wall after the upper grippers are released and which comprises a ruler extending in the direction of a generatrix of the upper cylinder, and an actuating system for extracting the ruler from the upper cylinder during a folding phase and then retracting it.
Dependencies are inferred from the claim text.