US3201029A

US3201029A - Valved bag

Info

Publication number: US3201029A
Application number: US286387A
Authority: US
Inventors: Batosti Mario; Belloni Antonio
Original assignee: Edison SpA
Current assignee: Edison SpA
Priority date: 1963-06-07
Filing date: 1963-06-07
Publication date: 1965-08-17
Anticipated expiration: 1982-08-17

Description

2 Sheets-Sheet 1 M. BATOSTI ETAL VALVED BAG lnruinnaxuiz. q llllllll 1- llll I: i v: 3.5.1..- ..ln- 5.1.235:

Aug. 17, 1965 Filed June '7, 1963 MARIO BATOST I ANTONIO BELLONI g- 1965 M. BATOSTI ETAL VALVED BAG 2 Sheets-Sheet 2 Filed June '7, 1963 INVENTORS BATO 6T1 ANTONIO BELLON l MARIO ATTORNEY United States Patent 3,201,023 VALVED BAG Mario Batosti, Milan, and Antonio helical, Padova, ltaiy, assignors, by mesne assignments, to Edison, Milan, Italy, a corporation of ltaiy Filed June 7, H63, Ser. No. 286,387 4 Ciaims. (tCl. 229-625) This invention relates to a valved bag and method of forming same, having squared off, sealed ends, in at least one of which there is formed a tubular valve of the type which closes automatically as a result of the thrust exerted by the material with which the bag is filled. More precisely, this invention relates to a bag manufactured of a plastic material having a substantially square shape which is capable of offering excellent mechanical resistence and reliable stability in an upright position when filled.

At present, bags of synthetic material with or without valves, are closed at the two ends by welding of the tubular envelope forming the bag, so that, when filled, they have difficulty in remaining upright and steady; on the other hand, those bags having glued-on bottoms or the like, i.e. bottoms which are distinct from the tubular envelope and which are generally closed by glueing the bottoms thereon, have little mechanical strength at the glued portions.

An object of this invention is to provide a bag with squared off ends and a method of preparing the same such that the filled bag will have a parallelepiped-like shape and will have excellent stability and sturdiness.

Another object of the invention is to provide a simple and practical method of preparing a valve bag manufactured of a synthetic plastic material, which valve provides a secure seal even when the bag is filled with powdery or generally incoherent material.

Still another object is the provision of a valved bag and method which is particularly suitable for continuous machine production at relatively low cost with a minimum of waste.

These and other objects and advantages will be readily appreciated from the following description.

In accordance with this invention our novel valved bags having a substantially squared off shape may be manufactured from a flattened tubular piece of synthetic material or ffom a sheet of same which can be formed into a tubular configuration. The valved bags of this invention are characterized by substantially squared off fiat rectangular ends. Where sheet material is used initially, the opposite sides are joined, for example, by welding to form tubes of the material. The corners are then closed by sealing means running at 90 angles to the aforesaid jointure. A tubular valve is formed in one of said closed ends, which valve is defined laterally by overlapping areas of the bag sides and by the transverse joining of said areas, communicating with the inside of the bag by a slit formed in the innermost sideof said overlapping ends which form the ends of the bags.

The invention will now be described in greater detail according to a preferred but not exclusive embodiment thereof, with reference to the accompanying sheet of drawings which illustrate without limiting the invention and in which:

FIG. 1 shows in a perspective view a starting portion of tubular plastic with open ends, and illustrates the starting stage for the manufacture of a valved bag according to the invention;

FIG. 2 shows also in a perspective view a second operational stage comprising the transverse joining of the ends of the tube.

FIG. 3 shows a plan view of a bag with ends finished 3,Z@.l,fi29 li atented Aug. 17, 1965 and with the waste pieces still to be removed, and in which the position is rotated through with respect to FIG. 2;

FIG. 4 shows in a perspective view two extreme portions of the closed ends of the bag with the waste pieces still to be removed, but rotated with respect to FIG. 3, and in which the tubular valve in accordance with the present invention is visible in one of said closed ends.

FIG. 5 shows a plan view of a finished bag prepared in accordance with the method of this invention.

FIG. 6 shows a partial perspective view of the end of the valved bag illustrating the position of the communicating slit;

FIG. 7 represents a perspective view of the valved bag immediately after closure of the flaps and illustrates the communication to the inside of the bag through the slit; and

FIG. 8 shows a partial perspective view of another operational stage in the preparation of the valved bag and illustrates the relation of the flaps to the communieating slit immediately prior to closure.

With reference to these figures, the valved bag to which this invention relates is formed from a length of plastic tube or from a plastic sheet which can be reduced to a tubular form, which is first flattened and the ends thereof are then closed by successive folding, overlapping and welding operations, as will be hereunder described, so as to. form squared off bottoms, the valve being provided for in at least one of said bottoms.

After the flattening of the tubular piece of plastic material the flattened tube 1 (FIG. 1) is partially cut at the opposite ends along the lines of flattening so as to obtain two pairs of free ends viz.,

flaps

2, 3 and 4, 5; in flap 5 there is cut a longitudinal slit 5 which serves, as will be disclosed hereinafter, to put the valve in communication with the inside of the bag; a piece end of flap 4 is cut-oif so that flap is made shorter than flap 5 in order to better'define the valve entrance area.

Flaps

2, 3 and 4, 5 are then folded inwardly along lines 6, 6 and 7, 7' so as to overlap each other as indicated in FIGURES 2 and 8 and to form open ended sheath-like herns.

In doing this, care should be taken that cut-off flap 4 overlaps externally the cut in flap 5.

The inner flaps are fastened to the outer flaps by means of the pairs of the transverse and

superposed welds

8, 8' and 9, 9 respectively; said welds being carried out in a single stage by introducing into the interspace formed by the folded

inner flaps

3 and 5, insulating members which serve to prevent the welding together of the upper half with the lower half of the inner flap.

During these welding operations, near cut 5 of the flap 5, a longitudinal weld 10 is made in order to join the outer flap 4 to the inner flap 5 in a zone which is situated on the portion opposite to that which will form the valve. In this manner (FIGURES 2 and 3), the valve is in practice defined by the tubular zone formed by cut-off flap 4, flap 5 and delimited by a part of the

parallel welds

8, 8 and the weld 10. The valve thus communicates with the inside of the bag through slit 5' while weld 1t) defines the length of said valve as shown in FIGURES 6, 7 and 8.

Once the pairs of welds S, 8' and 9, 9' and weld 119 have been completed, the bottoms folded over one another remain open at their ends. To close them, the bottoms and a contiguous zone of the longitudinal edges of the flattened tube are first spread transversely to the plane of flattened tube 1 and then the corners of these bottoms including the above said contiguous zone are overturned in the direction of the center line of tube 1 by bending them through an angle of 180, whereby the openings of the bottoms are covered by the corner zones which then assume a quadrangular shape. The open covered ends than the underlying flap 5.

of the bottoms are then closed by means of longitudinal welds ll, 11 and 12, 12' by inserting between the

triangular zones

13, 13', 13 and 13 and the bottoms of the bag, isolating sheets so as to avoid welding up the triangular zones to the bottoms of the bag. With these welds, the

triangular zones

13, 13', 13" and 13" form waste pieces or ears which are subsequently cut off.

At the valve entrance zone, waste ear 13 has a different shape from the'other waste ears, for flap 4 is shorter Waste car 13", therefore, when removed, leaves a free entrance'to the valve as shown by the numeral 14 in FIGURES 4, 5, 6, 7 and 8. In FIG. 4, for clearness sake, the waste pieces or

cars

13, 13 and as Well as 13 and 13" not shown in the figure, are rotated with respect to FIGURE 3. The actual path of communication with the interior of the bag is shown by the arrows in FIGURES 6, 7 and 8.

With

longitudinal welds

11, 11, 12 and 12, which are at an angle of 90 to transverse welds ti and 9, the bottoms of the bagassurne a squared off shape when the bag is filled, and cause the whole bag to assume a parallelepiped (squared off) shape of excellent stability both when the bag is upright by itself and also when it is stacked away with other like bags.

The pair of

transverse welds

8 and 9, which join the overlapping flaps making up the bottoms at two zones, confer. a mechanical strength on the whole which is much greater than that obtained by glueing and like systems, while the valve formed in one of said bottoms enables a perfect seal to be provided for against accidental leakage of materials, even when said materials are finely powdered.

In summary, the method of the invention comprises cutting up a tubular film or joining the edges of opposite position to the flap having the longitudinal slit therein and overlapping the thusly formed flaps in such a manner that the flap having the longitudinal slip lies interiorly. The transverse edge of the longitudinally slit flap is then joined to the interior of the opposite side of the tube and the transverse edge of the opposed flap is joined to the exterior of the opposite side of the flattened tube. The same technique of overlapping and joining the free ends on the opposite end of the tube is followed with these ends. The overlapped ends of the tube are then transvers'ely flattened. 'The open ends are then folded inwardly (as shown in FIG. 4) and the corners joined to form a sealed bottom or top for the bag as the case may be. It will be appreciated that by utilizing the simple and practical method of this invention a valve is automatically formed which may be readily used for filling and emptying and which also provides a secure seal even when the bag is filled with powdered material. 7

It will also be readily apparent that within the scope of the present invention, the tubular valve may be formed in one or both ends of the bag and moreover, more than one valve may be formed in each end. In the latter case, two longitudinal slits 5 will be effected on the flap at a suitable distance one from the other.

Obviously, in pactice, the materials employed and the dimensions of the various constituent parts may vary according to requirements, without departing from the scope of the invention.

We claim:

'l. A valved bag of synthetic materialrhaving welded ends and a substantially squared oif shape, comprising; a flattened tube of synthetic material partially slit longitudinally along the flattened edges thereof forming a pair of free end flaps on each end of said tube; said free end flaps of the two opposite sides being overlapped and conjoined by means of welds located transverse tothe flattened tube, and closed on the corners thereof by Welds located at ninety degree angles to the said transverse welds; a longitudinal slit located in the inner flap of one of said overlapping ends intermediate from the-side there-,

of; a tubular valve formed in the end having said slit;

said valve being laterally defined by the said overlapping claim 1 wherein the welds conjoining the overlapping ends are located transverse to the flattened tube edges and.

longitudinal near the communicating slit, said weld adjacent to the slit defining the length of the tubular valve.

4. A valved plastic bag having welded ends and a substantially squared off shape, comprising; a flattened tube of plastic material partially slit longitudinally along the flattened edges thereof forming a pair of free endflaps on each end of said tube; said free end flaps of the two opposite sides of the tube conjoined by means of welds located transverse to the flattened tube and closed on the corners thereof by welds located at ninety degree anglesv to the said transverse welds; a longitudinal slit located in the inner flap of one'of said overlapping ends and intermediate from the side thereof; a tubular valve formed in V the end having said slit; said valve being laterally defined by the said overlapping ends area of the tube sides and by the said transverse welds, and. communicating with the inside of the tube through said slit.

References Cited by the Examiner FOREIGN PATENTS 178,328 4/54 Austria. 474,261 9/52 Italy. 507,225 12/ 5 4 Italy. 974,534 1/ 61 Germany.

FRANKLIN T. GARRETT, Primary Examiner.

Claims

1. A VALVED BAG OF SYNTHETIC MATERIAL HAVING WELDED ENDS AND A SUBSTANTIALLY SQUARED OFF SHAPE, COMPRISING; A FLATTENED TUBE OF SYNTHETIC MATERIAL PARTIALLY SLIT LONGITUDINALLY ALONG THE FLATTENED EDGES THEREOF FORMING A PAIR OF FREE END FLAPS ON EACH END OF SAID TUBE; SAID FREE END FLAPS OF THE TWO OPPOSITE SIDES BEING OVERLAPPED AND CONJOINED BY MEANS OF WELDS LOCATED TRANSVERSE TO THE FLATTENED TUBE, AND CLOSED ON THE CORNERS THEREOF BY WELDS LOCATED AT NINETY DEGREE ANGLES TO THE SAID TRANSVERSE WELDS; A LONGITUDINAL SLIT LOCATED IN THE INNER FLAP OF ONE OF SAID OVERLAPPING ENDS INTERMEDIATE FROM THE SIDE THEREOF; A TUBULAR VALVE FORMED IN THE END HAVING SAID SLIT; SAID VALVE BEING LATERALLY DEFINED BY THE SAID OVERLAPPING ENDS AREA OF THE TUBE SIDES AND BY THE SAID TRANSVERSE WELDS, AND COMMUNICATING WITH THE INSIDE OF THE TUBE THROUGH SAID SLIT.