subject: Summary Of Pp Woven Bag [print this page] It is a primary object of the present invention to provide a practical bag in which the above-mentioned defects involved in the conventional bags are eliminated and an economical process for manufacturing such a bag.
In accordance with the present invention, there is provided a pp woven bag for use in storing and transporting a bulk material, having a cylindrical body portion of the bag proper, top and bottom end portions which close top and bottom openings of said bag proper, a cylindrical portion providing an opening for filling the bag and formed in the central portion of said top end portion, a plurality of hanging slings sewn to said bag body portion at predetermined positions adjacent to said top end portion, wherein said top end portion is formed integrally with said bag proper and sutured by a seam formed along a line passing through a central line in the longitudinal direction of said bag. The cylindrical portion for filling material may be formed of a material different from the material of the bag proper and sewn to the top end cover at the center thereof.
Another aspect the present invention provides a process for manufacturing a bag comprising a cylindrical body portion of the bag proper, top end and bottom end portions which close top and bottom openings of said bag proper, a cylindrical portion providing an opening for filling material formed in the central portion of said top end portion, comprising a first step of creating a cylindrical body corresponding to said bag proper provided with a pair of upper projections, having an identical shape and dimensions, projected from the upper edge portion thereof at two symmetrical positions with regard to the central axis of said cylindrical body, a second step of closing a bottom opening of said cylindrical body with said bottom end cover by sewing it to the bottom edge of said cylindrical body, a third step of superimposing said upper projections whereby said upper edge portion of said cylindrical body is divided into two edge portions capable of being superimposed on each other so that two L-shaped superimposed edge portions are symmetrically created with respect to the longitudinal center line of said superimposed upper projections, a fourth step of sewing said pair of L-shaped superimposed edge portions.
Accordingly, in preparing a bag according to the present invention, the sewing operation is conducted only for connecting the edge of the top end portion to the material charging cylindrical portion formed by cutting off the excess portions along L-shaped lines. Therefore, the sewing operation is simplified and is performed at a high efficiency compared with that of the known bags. Furthermore, in this case, since the portion for filling is formed integrally with the bag proper, the operation of charging a material into the bag from a top filling opening of the charging cylindrical portion can be performed very smoothly and the final bag is excellent in its adaptability to the charging operation.
