US 2689678 A
Description (OCR text may contain errors)
Sept. 21, 1954 D. D. WEN T 2,689,678
Filed Nov. 9, 1950 Snventor attorneys Patented Sept. 21, 1954 BAG Donovan D. Wendt, Minneapolis, Minn., assignor to Bemis Bro. Bag
corporation of Missouri Application November 9, 1950, Serial No. 194,809
My invention relates to a novel self-ventilating bag formed from imperforate tubular material and to the method of forming same.
The primary object of my invention is the provision of a conventional bag formed from imperforate tubular material and which is intended for the holding of commodities in chunk form, which automatically becomes self-ventilating when the chunk contents are placed therein.
A further object of my invention is the provision of a self-ventilating bag which has no material removed therefrom and is, therefore, not weakened with respect to stresses exerted on the bag longitudinally thereof.
A still further object of my invention is the provision of a bag for chunk style contents in which the ventilating means will not be closed in part by said contents.
A still further and highly important object of my invention is the provision of a bag having a plurality of laterally-spaced longitudinally-extended slits adjacent the upper and lower end portions thereof-which slits will automatically open under the stress exerted on the walls of the bag when the chunk contents are inserted therein and which will permit ventilation or passage of air completely through the bag even when the bags are piled one upon the other in horizontal (side-by-side) relationship.
A still further object of my invention is the provision of an elongated tubular bag of the class described, which is formed from imperforate thermoplastic material and which is provided only adjacent its opposite ends with circumferentially-extended rows of laterally-spaced ventilating slits-useful and necessary to the merchandiser of chunk-style goods such as oranges, apples, potatoes, and the like-but which ventilating slits may be cut off by the purchaser whereby to produce an imperforate tubular element which may be resealed by said user at one or both ends to provide a utility bag for packing food commodities in refrigerators, freezers, and the like.
A still further object of my invention is the provision of a novel method of providing a selfventilating bag from imperforate thermoplastic material, namely, by the use of cutting knives which have been heated to a sufficient temperature to cause heading of the edges of the slits so as to tend to check the tendency of the material to slit further.
The above and still further objects and advantages of my invention will become apparent from the following detailed specification, appended claims, and attached drawings.
Minneapolis, Minn., a
Referring to the drawings, wherein like characters indicate like parts throughout the several views:
Fig. 1 is a view in side elevation of a bag constructed in accordance with my invention;
Fig. 2 is a view corresponding to Fig. l but illustrating the bag with chunk-type contents therein;
Fig. 3 is a view in transverse section, taken on the line 3-3 of Fig. 1;
Fig. 4 is a fragmentary perspective view, illustrating a step in the method of producing my novel bag;
Fig. 5 is a view in section taken substantially on the line 5-5 of Fig. 4; and
Fig. 6 is a view in perspective, illustrating my self-ventilating bag structure when a plurality of same, with contents therein, are stacked one upon the other.
Referring with greater particularity to the drawings, the numeral I indicates, in its entirety, an elongated tubular bag, as shown, formed from a single sheet of flexible imperforate material folded upon itself to provide a closed bottom 2, a front wall 3, and a rear wall 4. The front and rear walls are secured together at their side edges, as indicated at 5. The bag I, prior to placing contents therein, is open at its top portion 6.
In order to assure ventilation to chunk-type contents within the bag I, such as oranges, apples, potatoes, and the like, I provide the imperforate front and rear walls 3 and 4 thereof with a plurality of laterally-spaced generally longitudinally-extending slits 1 intermediate the top 6 and the bottom 2 and preferably in spaced relation to each thereof. In fact, I have found that it is preferable to arrange the slits 1 in circumferentially-spaced rows 8, one adjacent the upper end portion 6 and one adjacent the lower end portion 2. As shown in Fig. 2, these slits 1 will open up when chunk-type contents such as oranges A are placed therein. This is due to the uneven stress or pressures exerted upon the walls 3 and 4 of the bag I by the oranges A. It should be obvious that when the slits l are in the open condition of Fig. 2, air is permitted to pass completely through the tubular and imperforate bag I, thus preventing spoilage of the contents. Furthermore, in view of the fact that the rows 8 of slits 1 are spaced one adjacent the bottom 2 and one adjacent the top 6 (which, of course, is closed in one manner or another after the contents A are placed therein), passage of air through the bag I through the slits 1 will not be curtailed or restricted, even when the bags I,
with contents therein, are stacked in a conven-.
3 tional manner, that is, in horizontal side-by-side relationship, one upon the other as shown in Fig. 6.
One inherent advantage of providing the bag I with slits 1, as distinguished from cutting out ventilating apertures from the walls 3 and 4 thereof, is that the tensile strength of the walls 3 and 4 is not weakened with respect to stresses exerted longitudinally of the bag.
Other advantages derived from placing the circumferentially-extended rows of generally vertically-extended slits adjacent one or both ends of the bag are numerous. For instance, when so positioned, a relatively wide band at the central portion of the bag remains unobstructed for printed and other advertising material as well as increased visibility. The'advantage of this arrangement is that it allows draw cords to' be run through either or both of the circumferentially-extended rows of slits to form a closure for either, or both ends of the bag, either for original or reuse purposes.
My invention is particularly adaptable to bags formed from imperforate thermoplastic material such as polyethylene. When material of this type is utilized, I preferably out the slits I with a cutting knife 9 (see Fig. 4) which has been preheated to a temperature sufiicient tomelt the thermoplastic material immediately adjacent the blade It) so as to cause the material to shrink or roll back slightly. so, a to cause a bead II to be, formed about the slits I. These beads or. reinforced edges I I obviously tend to prevent further slitting of the material such as may be caused by lifting the bag I, with contents therein, from either side edge l2.
My invention has been thoroughly tested and found to be completely satisfactory, for the accomplishment of the above objects; and, while I have disclosed a preferred embodiment of my invention, it is obvious that the same is capable of modification without departure from the spirit and scope of the invention as. defined by the appended claims.
What I claim is: I v
l. A tubular bag of thermoplastic material in cluding opposed normally flat rectangular side Walls, a row of ventilating slits in at least one of said walls, said row of slits being disposed adjacent an end of the bag transversely of said side walls, and said slits being transversely spaced and extending longitudinally of the side walls in parallel relation to each other, the edges of said slits defined by reinforcing beads and being substantially in contact in the normal flattened condition of the bag and the slits opening upon distension of the side Walls under fill of the bag.
"in tubular bag of thermopalstic material including opposed normally flat rectangular side walls, a row of ventilating slits in each side Wall adjacent each end of the bag, the rows of slits extending transversely of the side walls and the rows of slits in one side wall being substantially opposite the rows of slits in the other side wall, theslits" being transversely. spaced and extending longitudinally of the side walls in parallel relasome each other, the edges of said slits defined by reinforcing beads and being substantially in contact'in the normal flattened condition of the bag and the slits openingupon distension of the side walls under i lll of the bag.
References Cited in the file of this patent