US 3889872 A
A plastic bag comprising a bag body, at least one retention member which is formed close to the bag opening by hot sealing a plastic sheet or film at least at two points on said bag body in order to provide a passage between the said two adjacent points, and an endless band movably retained in said passage. The bag can be tightened simply by self-fastening the said band.
Description (OCR text may contain errors)
United States Patent 1191 Lin 1 1 PLASTIC BAG HAVING TIGIITENING BAND  Inventor: Spencer B. T. Lin, 3F, No. 5, Ln. 4,
Chin Chou St., Taipei, Taiwan, China  Filed: Aug. 14, I973  App]. N0.: 388,190
 US. Cl. 229/63; 24/30.5 R; 24/30.5 P; 150/11  Int. Cl. B65D 33/28  Field of Search 229/63, 54 C, 62; 150/11, 150/3; 24/305 R, 30.5 P
 References Cited UNITED STATES PATENTS 906,447 12/1908 Moore .f. 229/63 2,533,829 12/1950 Merryweather 150/3 X 2,799,611 7/1957 Dreisbach 229/63 X 1 June 17, 1975 3,620,774 11/1971 Ford et a1. 229/63 X 3,653,583 4/1972 Meyer 229/63 X FOREIGN PATENTS OR APPLICATIONS 1,368,287 6/1964 France 150/3 1,276,833 10/1961 France r 150/3 531.172 6/1955 Italy 24/305 R Primary Examiner-Wi11iam 1. Price Assistant Examiner-Stephen P. Garbe  ABSTRACT A plastic bag comprising a bag body, at least one retention member which is formed close to the bag opening by hot sealing a plastic sheet or film at least at two points on said bag body in order to provide a passage between the said two adjacent points, and an endless band movably retained in said passage. The bag can be tightened simply by self-fastening the said band.
1 Claim, 6 Drawing Figures PLASTIC BAG HAVING TIGHTENING BAND FIELD OF THE INVENTION The present invention relates to a plastic bag, and more particularly. to a plastic bag which utilizes an endless band, passing through a retention member which is formed by hot sealing a plastic sheet or film on said bag, to tighten the bag opening by self-fastening.
BACKGROUND OF THE INVENTION Plastic bags have been widely used for packing purposes. Especially. the polyethylene bag has various advantages, such as a neat appearance, transparent. nontoxic, low cost, impermeable to water etc. so that it is more suitable to be used for packing foods, such as vegetables, fruits, fishes and meals etc. and has become an indispensable packing material used in the market or store.
But the plastic bag with goods contained therein has to be further tightened by a band, rope or string to prevent the goods from dropping out ofthe bag. This tightening operation takes time. which will in turn require an increase in the working capacity, even to an extent that it obstructs the procession of sales.
By now, there are several kinds of plastic bags having a quick tightening feature. the so called union bag, for instance. This provides a tongue and groove structure along the entire transverse length near the bag opening. It simply needs a slight pressure to be applied on the portion of the said tongue anti groove structure to connect them, so as to readily tighten the opening. This tightening operation is quite simple, but the production cost ofsuch bag is relatively high. In addition, the tightening strength of the tongue and groove structure is not enough to stand for a bag containing heavy goods or one that is full of goods and will release and disconnect. Moreover, the said union bag has no handling means for carrying by hand. Therefore. the union bag is generally limited to a size smaller than the palm area and generally used to fill with medicine or flower seeds etc.
Another kind of conventional plastic bag is formed with a tube-like annular passage by holding the top edge of the bag opening and hot sealing it on the bag. The annular passage has a cut for introducing a band therethrough. The band can be fastened to close the opening and handled by hand. But the main disadvantage is that when the bag is filled with heavy goods and carried with the said band, the gravity force of the content almost concentrates at the bag opening. The annular passage which receives the band thus has a great stress. The tensile strength of the plastic film is generally decreased at the portion being hot sealed. It will thus cause the said portion to be easily torn off or broken with the increased stress thereon.
SUMMARY OF THE INVENTION The plastic bag according to the present invention comprises a bag body having at least one retention member which is formed close to the bag opening at a suitable distance by hot sealing a plastic sheet or film at least at two points on said bag body in order to provide a passage between the said two adjacent points, and an endless band movably retained in said passage. This bag can be tightened simply by self-fastening the said band.
The present plastic bag with said structure can eliminate the drawbacks of the above mentioned conventional plastic bags, and provides an advantage of a quick tightening operation. Further, when the bag is tightened, the stress is applied on the bag body, and the hot sealed portion will not be effected by the stress to cause any damage.
The main object of the present invention is to provide a plastic bag which utilizes an endless band, passing through a retention member which is formed by hot sealing a plastic sheet'or film on said bag. to tighten the bag opening by self-fastening. and the fastened band can be readily carried by hand.
Other objects and features of the present invention will be apparent from the following description with reference to the annexed drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view depicting the plastic bag of an embodiment according to the present invention;
FIG. 2 is a sketch depicting the tightened status of the bag opening by means of the tightening band attached thereon;
FIGS. 3 to 6 are front views depicting various modified embodiments of the plastic bag according to the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Referring to FIG, 1, the blow molded plastic bag is generally hot sealed at a suitable portion 2 on bottom of the bag body 1. The content is filled from the opening 3. The characteristics of an embodiment of the plastic bag according to the present invention is shown in FIG. 1, where the bag is provided with two retention members 4 and 4 near the opening 3 of the body 1. The retention members 4 and 4 have three hot sealing points 41, 41 and 41". A passage is formed between two adjacent hot sealing points, such as 41 and 41 or 41 and 41". An endless band 5 can be freely moved into the said passage.
The plastic bag of the present invention is preferably made of polyethylene, so that, the retention members 4 and 4 also preferably employ polyethylene plastic sheet or film for readily being hot sealed on body 1. As for the tightening band 5, this is preferably made of polypropylene.
In general, the length of band 5 is from about one to twofolds of the bag width. But, actually, it can be varied as required. The distance between two retention members 4 and 4 is slightly smaller than the double length of band 5 in order that when the band 5 is movably retained in the two members 4 and 4, the bag body 1 will have a uniform appearance.
To perform the tightening operation after the content has been filled into the bag, one only needs to take the both extending return ends 51 and 51 to another side of the bag, i.e., so that the band 5 surrounds the body 1. Then one takes one end 51 or 51' and passes it through the other end 51' or 51 to fasten them. The opening 3 is thus tightly closed, and the extending end 51 as shown in FIG. 2 may be carried by hand. When the bag is tightened, the stress is mostly applied on the body 1 at the portion corresponding to the said retention members 4 and 4, and will not cause any trouble to the hot sealed points 41, 41 or 41".
The aforementioned arrangement is merely a preferred embodiment and the present invention can take various forms. For example, as shown in FIG. 3, there is only one retention member 4. Two passages are formed between three hot sealed points and the band recycles through said two passages. FIG. 4 illustrates another embodiment which has two retention members 4 and 4, each hot sealed at two points 41 and 41' to form only one passage. Further, the level of retention members 4 and 4, namely, the distances between the said retention members and top edge of opening 3 are different. FIG. 5 is an embodiment similar to that shown in FIG. 4, but the said levels of the members is about the same. FIG. 6 shows still another embodiment which provides only one retention member 4 with two hot sealed points.
The aforementioned embodiments serve only for illustrative purposes and by no means to restrict the scope of the present invention. Any modifications can easily be made by those skilled in the art and should be considered within the scope of the attached claims.
l. A plastic bag comprising a bag body, at least one retention member formed on said body at a predetermined distance from a bag opening, said retention member comprising a patch of plastic sheet or film having a length less than the entire circumference of said bag body and being hot sealed at least at three points on said bag body to define at least two passages in each retention member, and an endless band movably retained in the said passages.
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