Patent ID: 7603832

Claim:
A method of forming a packing bag comprising: traveling a packing plastic bubble material sheet pulled out from an original roll along a triangular plane of a triangular plate while applying a tension to the material sheet along oblique sides connecting a base and a vertex of the triangular plate; sliding the material sheet from the base to the vertex while applying a reaction for curbing a drawn quantity of a middle portion of the material sheet in a width direction to both sides of the material sheet in a width direction that is contained in an overlapped portion; forming a bending portion on a side of the vertex and a triangular open aperture on a side of the base by folding the material sheet using the vertex; drawing out the width-direction middle portion and the overlapped width-direction sides while holding the bending portion through a pair of drawing rolls; and fusing and cutting the overlapped portion in a width direction using a fusing and cutting device to consecutively form a packing bag having the bending portion as a bottom and the open space as an insertion aperture for a packed member.