Patent ID: 6561963
Filing Date: 2003-05-13
Classification: B31B,B65D

Abstract:
An apparatus for successively making plastic bags each of which includes two layers of panel portion superposed to define aligned top edges, first and second side edges and bottom edges, and plastic bag further including a first side gusset portion disposed between and extending along said first side edges, a second side gusset portion disposed between and extending along said second side edges, and a bottom gusset portion disposed between and extending along said bottom edges, said apparatus comprising:feeding means for feeding a main material intermittently for a length along a feeding path, said main material comprising said layers of panel portion and said first and second side gusset portions continuing longitudinally thereof respectively, said feeding means feeding said main material longitudinally of said layers of panel portion and said first and second side gusset portions; cutting means disposed at a position determined along said feeding path for cutting one of said two layers of panel portion as well as said first and second side gusset portions widthwise of said main material and leaving the other said two layers of panel portion continuing, to form an opening in said main material, whenever feeding said main material intermittently; inserting means disposed downstream of said cutting means along said feeding path for inserting an additional material between said layers of panel portion through said opening, whenever feeding said main material intermittently, said additional material comprising said bottom gusset portion; wherein each of said first and second side gusset portions is folded into halves along a center line extending longitudinally thereof, superposed into two layers and interposed between said layers of panel portion, said first side edge being connected with each other by said first side gusset portion, said second edges being connected with each other by said second gusset portion, said bottom gusset portion being folded into halves along a center line extending longitudinally thereof, superposed into two layers and interposed between said layers of panel portion, said bottom edges being connected with each other by said bottom gusset portion, said bottom gusset portion having first and second ends at which first and second auxiliary gusset portions are formed, each of said first and second auxiliary gusset portions being folded from said layers of bottom gusset portion along folded lines extending at an angle of about 45Â° with respect to said center line of bottom gusset portions, said first auxiliary gusset portion being further folded into halves along a center line which is an extension of said center line of bottom gusset portions, to be superposed into two layers, one of which is interposed along with one of said two layers of bottom gusset portion between of said two layers of panel portion and one of said two layers of first side gusset portion, the other of said two layers of first auxiliary gusset portion being interposed along with the other said two layers of bottom gusset portions between the other of said two layers panel portion and the other of said two layers of fist side gusset portion, said first gusset portion being connected with said bottom gusset portion by said first auxiliary gusset portion, said second auxiliary gusset portion being further folded into halves along a center line which is an extension of said center line of bottom gusset portion, to be superposed into two layers, one of which is interposed along with one of said two layers of bottom gusset portion between one of said two layers of panel portion and one of said two layers of second side gusset portion, the other of said two layers of second auxiliary gusset portion being interposed along with the other of said two layers of bottom gusset portion between the other of said two layers of bottom gusset portion of panel portion and the other of two layers of second side gusset portion, said second side gusset portion being connected with said bottom gusset portion, said second side gusset portion by said second auxiliary gusset portion; and bottom gusset sealing means disposed downstream of said inserting means along said feeding path for heat sealing said layers of panel portion with said layers of bottom gusset portion and heat sealing said layers of first and second auxiliary gusset portions with said layers of first and second side gusset portions along said opening respectively, whenever feeding said main material intermittently.