US 3264794 A
Abstract available in
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Description (OCR text may contain errors)
Aug. 9, 1966 w. A. BROWN ET AL 3,264,794
PACKAGING APPARATUS 7 Filed March 26, 1963 5 Sheets-Sheet l WILBER A. BROWN CHARLES H. FAWKNER INVENTORS. EUGENE W. GEIGEL CHESTER D- RHODES BY W tv MM TTORNEY.
Aug. 9, 1966 w. A. BROWN ETAL 3,264,794
PACKAGING APPARATUS Filed March 26. 1963 5 Sheets-Sheet 2 240 eed WILBER A. BROWN CHARLES H. FAWKNER INVENTORS. EUGENE W. GEIGEL CHESTER D. RHODES ATTORNEY.
Aug. 9, 1966 w. A. BROWN ET AL 3,264,794
PACKAGING APPARATUS Filed March 26, 1963 5 Sheets-Sheet 3 WILBER A. BROWN CHARLES H- FAWKNER INVENTORS EUGENE W. GEIGEL CHESTER D- RHODES BY ATTORNEY- United States Patent 3,264,794 PACKAGING APPARATUS Wilber A. Brown, Springfield, Charles H. Fawkner, Am-
herst, Eugene W. Geigel, Springfield, and (Ihester D.
Rhodes, Wilbraham, Mass, assignors to Monsanto Company, a corporation of Delaware Filed Mar. 26, 1963, Ser. No. 267,978 8 Claims. (CI. 53-29) The present invention relates to the packaging of materials in plastic bags. More specifically, this invention relates to packaging apparatus which uses a continuous tube of plastic material fed to the apparatus from a roll of the material in flattened condition.
Up to the present time, the general method for packaging pulverulent or other materials of volumetric capacities of more than one cubic foot has been to fill essentially rectangular bag blanks which are supplied to the filling or bagging machine from a magazine containing the bag blanks or other type of stacked arrangement. When the body of the :bag was comprised of paper or other materials which had some rigidity, few difiiculties were encountered with the general operations associated in the packaging steps, i.e., bag blank pick-up, opening, filling, etc. However, with the advent of the thermoplastic type bags serious problems were encountered when the more flexible thermoplastic materials were used as packaging materials. In particular, the extreme flexibility of many of the thermoplastic materials which have been fabricated into bags has caused serious difiiculties, i.e., plug-ups, jamming, etc. during pickup and transfer of the bag blank from the magazine or stack to the filling station. These problems were further aggravated due to the diificulties of opening and supporting the rather flexible bag blanks before and during the filling operation. It has now been found that these problems are substantially resolved by new and novel packaging means and expedients which are simple in application but which present hitherto unappreciated results.
Accordingly, it is the principal object of this invention to provide improved apparatus means and methods for packaging materials in thermoplastic bags.
Another object of this invention is to provide apparatus means and methods for packaging materials which utilizes a continuous tube of plastic material in flattened condition.
Other objects of the present invention will in part be obvious and will in part appear hereinafter.
These and other objects are attained by transversely sealing a continuous tube of thermoplastic material at predetermined intervals along its length, transversely severing the tubular material adjacent each seal to form a bag blank sealed at one end, transferring the bag blank to a filling station where it isfilled with materials to be packaged, after which its open end is closed. A special expedient may be used for separating the parallel edges at the open end of the bag sutficiently to permit the bag to be filled which comprises clamping the bag blank across its width /2 to 1 /2 inches adjacent its open end and causing a projection to move parallel and in contact with the open end of the bag.
The following drawings are provided for the purpose of illustrating various embodiments of the present invention.
FIG. I is a side view, partly in section and with parts broken, illustrating mechanism for feeding and severing a continuous tube of thermoplastic film.
FIG. II is a front view, partly in section and with parts broken, of the same embodiment shown in FIG. I.
FIG. III is a front view, partly in section and with parts broken, of the same embodiment shown in FIG. II except that the thermoplastic tube has been severed form- "ice ing a bag blank which is in a stage of lateral advancement.
FIG. IV is a fragmentary side view, magnified and with parts broken, illustrating a modified embodiment of the present invention wherein the apparatus is adapted to heat seal the tube of thermoplastic film at predetermined intervals.
Referring in detail to the figures of the drawings, and more specifically to FIGS. I and H, there is schematically shown apparatus for packing materials in thermoplastic bags.- More specifically, a continuous tube of thermoplastic film 10 is unwound from roll 12 and advanced by means of pull rolls 14 and 16 over support rolls 1'8 and 20, between the said pull rolls 1 4 and 16 to and between clamping belts 22a and 22b. In the embodiment shown in FIGS. I and II, the tubular film material 10 is shown transversely sealed such that the layers of the tube are adhered or fused together, at predetermined intervals along its length, i.e., 24a, 24b, 24c, etc., as it is unwound from roll 12. In this embodiment, the tubular film 10 was sealed during a prior separate operation not shown in FIGS. I and II. As illustrated in FIG. IY, it is sometimes desirable to transversely seal the tubular film after it is unwound from roll 12 in timed conjunction with the later severing operation.
In the embodiment illustrated in FIGS. I and II, color bands 26a, 26b, 260, etc. are marked at one end of each transverse seal 24a, 24b, 24c etc., respectively, at a position that will enable the color bands to pass directly in front of the lens of electric eyes 28 and 30 as the tubular film 10 advances. These bands may be of any color which is sufiiciently distinct from the tubular film to permit detection by the electric eyes. In general, it is preferable that the length of the color mark in the direction of advance be at least A3 of an inch or more depending, of course, on the sensitivity of the electric eyes. The purpose of the color bands and the electric eyes are to control the movement of the plastic film 10 as it advances towards clamp belts 22a and 22b. Clamp belts 22a and 22b are designed to move together on tracks 32a and 32b activated by pistons 34a and 34b when a predetermined length of film is positioned therebetween and film travel has been halted, after which knife 36 moves laterally across the tubular film severing same.
In the sequence of operations, pull rolls 14 and 16 are revolved to unwind and advance the tubular thermoplastic film 10. In the course of film advancement, a color bar marked on film 10 passes in front of electric eye 28 which detects the mark. Upon detection, electric eye 28 transmits a signal via electric means, not shown, to stop pull rolls 14 and 16 which in turn halt the advance of film 10. Since there is a time interval or lag between the detection and transmission of the signal from the electric eye 28, the color mark on film 10 will advance a distance beyond electric eye 28 before the film 10 is halted. To ensure that this distance remains the same each time the film is halted, a second electric eye 30 is positioned such that one of the color marks will come to rest in front of its lens. In the event the color mark does not come to rest in front of the electric eye 30, a signal is transmitted calling for either a manual or automatic adjustment of the film position. To optimize control, it is recommended that a slight tension be maintained between pull rolls 14 and 16. During proper operation, the electric eye system will cause the pull rolls to halt the advance of the tubular film 10 such that seal 24b is slightly above knife 36 after which clamping belts 22a and 220 move together clamping the tubular film l0 therebetween. Knife 36 then moves laterally severing the tubular film 10 to form a bag blank 40 sealed at its lower or bottom end by seal 24a. As may be seen in FIGS. II and III, clamp belts 22a and 22b initiate advancement of the now severed tube or bag blank -40 laterally by movement of the belts on rollers 42a, 42b;
42c and 42dwhich causes the edge or open top 44 of bag blank 40 which projects above b'elts 22a and 22b. to strike projection 46 at its forward corner forcing bag top' 44 to openor separate its parallel edges first atits corner and then across theentire top Width of the bag as the bag is force passed and in contact with projection 46 by belts Z ZZz'and 22b. If done properly, projection 462Wi1l cause the bag top 44 to open sufliciently to permit a filling nozzle 48 to enter for filling same, after Which the opening or bag top 44 is closed by means of tape or other suitable means not shown. Although the expedient used to open the bag blank appears to be simple, the positioning or relationship between projection and bag top 44 is critical. jects between /2 to 1 /2 inches depending on the flexibility Forexample, unless bag top 44 proof the bag above clamp belts 22a and 22b, the top edge of the bag will nottend to openproperly; To further illustrate, if the top edge projects too high above the belts, the flexibility of the thermoplastic film ,will. caus .both edges of the bag to be pushed to one side or. the
other without opening the bag blank. On the other hand,
if the bag top-does not project sufliciently above belts 22aand 22b, the bag will not open enough'to permit the filling spout to enter. When the bag is opened properly by projection 46, filling spout 40 will descend between the parallel edges of the bag blank 40 forcing belt clamps 22a and 22bto part sufliciently to permit'filling of the bag blank.
In the practice of the present invention, the tubular.
thermoplastic film material may be transversely sealed at intervals along its lengh before itis unwound, i.e., by the supplier or separate sealing operation, or the thermoplastic film material may be sealed as it is advanced FIG. IV illustrates a magnified through the apparatus. fragmentary portion illustrating a heat sealing mechanism 50'positioned in line immediately above the cutting knife 36. In the sequence of operations, when pull rolls Hand 16 have halted the advance of film 10, heating element 52 of the heat sealing mechanism 50 moves horizontally towards film 1t? pressing film 10 against back bar 54 of the heat sealing mechanism 50. r The heating element 52 then fuses the layers of the tubular film together. Positioning the heat sealing mechanisnrSG immediately above knife 36 has the advantage ofminimizing control problems by reducing and possiblyeliminating the need for theelectric eye system which positions the seal. However, it is obvious that the heat sealing mechanism may be located anywhere along the line. of advance of the tubular film 10 prior to the knife 36.=
/2 to 1 /2 inches adjacent its open end and causing a projection to move parallel and in contact with the open end of the bag.
As mentioned earlier, the thermoplastic tube may be sealed at any time prior to the tube severing operation either during a separate operation or in timed conjunction with the severing operation. Any suitable method for adhering or fusing the layers of the tube together in a line or band extending transversely and completely across the length of the tube may be used. The width? of the adhered or fused line or band may vary consid-% erably although widths of Ms to of an inch are recommended for good bonding while at the same time utiliz ing-a minimum area of seal. The preferred methodsof sealing are those which cause'the layers of the tubular film to .fuse together. This is generally accomplished by an electric heating element although other. means ofobtainingthe proper; fusion temperature may-also be used.
In thepractice of this invention, .thesheet is severed in conjunction with the filling operation. 1. Consequently, the problems 'cause drby stacking the bag blanks as described heretofore'are avoided. Inother words, the: bag blank istransferred or: conveyedftosthe filling station immediately after it is severed fromsthecontinuoustube.
This is, inzefr'ect, an in situ bag-forming and packaging i operation. ..Any suitable means. maybe used to ,sever the bag blank from thecontinuous tube .such as the shuttle-type knife described in;FIGS.-'I and II; a rotary knife, guillotine type and the like. If desiredgthe tubing may be preperforatediadjacent and parallel theseals to permita mechanical separation insteadof cutting the tube directly. Itis important, however, that: the tube be cut or separatedparallel the line of seal immediately adjacent the advanced or forward edge of the heat seal;
In this manner, a bag blank .will. be formed-having a sealed lower end and an open upperzend ready forfilling;
In the illustrated embodiment, the movement of the sheet was controlled by an, electric eye system. However, it is obvious that any system which will fairly accurately advance the tube predetermined distances Willi suffice;
A'special feature of the bag forming and packaging operation are the ,meanswused to: separate the parallel.
edges at the open end of the bag blank to permit a filling spout to'enter. As described above, this is ac? complished by clamping the bag across its width. a predetermined distance. below the open end of the bag and moving a projection parallel and in contact with the open end. 1
The thermoplastic tubular film can be fabricated from such plastic materials as polyethylene, polystyrene, polyethylene terephthalatmpolyvinyl chloride, polyvinyl ace- 1 tate, polyvinyl-idene chloride, polyisobutylene, polypro The pre-.- ferred thermoplastic film-materialis polyethylene, a solid,
pylene, polytetrafluoroethylene; and the like.
tough polymer ofethylene which can be manufactured inv film formin thicknesses less than zone mil.
moisture permeability,. and consequently, is anexcellent material for packaging uses.
The bags: formed in the practice; of this'invention ordinarily will have substantial volumetric capacity, e.g.,' at least .1 cubic foot, and'are ,designed-primarilyto carry about 50 to pounds of such common pulverulent; materials such as cement, ilour, fertilizer, carbon blaok chemicals and .the like. The .walls of the bag ordinarily will have a thickness of the order of 5 to 10 mils, al-
though obviously the .walls may be thinner or thicker astindicated by the use towhich the bags are to be put. If desired, the walls of the bag can befabricated from i a plurality ofplies of-thickthermoplastic film.
The above descriptions and particularly'the drawings,
are set forth for purposes of illustration only. Many variations and modifications thereof will be obvious to those skilled in the art; and can be made without departing from the spirit and scope .of the invention herein 1 described.
What is claimed is:
1., A method of packaging materials in plastic bags which'comprises the stepsloftransversely sealing a continuous tube .of thermoplastic film at predetermined in- I tervals alohg its length, transversely severing the tubular one end, clamping the: blankbagacross its width adjacent the open end-of the bag iblank, causing a ,projection:to move parallel-to andin contact with the open I end of said bag blank, whereby a filling spout may enter;
the bag, transferring said bag blankwtoya filling station,
It is light in weight, extremely low :in water absorption and Layersof polyethylene can be heat=sealed or fused together to present a strong bond.-.
filmvadjacent each, seal to ,form a bag .blank sealed at filling said bag blank with materials to be packaged and closing said open end of the bag blank.
2. The method according to claim 1 wherein the sealing is accomplished by heat sufficient to fuse the layers of the tube of thermoplastic film together.
3. The method according to claim 1 wherein the plastic film is polyethylene.
4. A bag forming and packaging apparatus adapted to use a continuous tube of thermoplastic film which comprises, in combination, sealing means for transversely sealing the thermoplastic tube at predetermined intervals along its length, driving means for advancing the tubular film along a predetermined path, cutting means for severing the tubular film parallel and adjacent each seal forming a bag blank sealed at one end, opening means for separating the parallel edges at the open end of said bag blank comprising clamping means for clamping the bag blank across its width adjacent its open end and a projection adopted to move parallel to and in contact with the open end of the bag and conveying means for transporting said bag blank to a filling station.
5. The apparatus according to claim 4 wherein sealing means comprise heating means capable of fusing the layers of the tube of thermoplastic film together.
6. A bag forming and packaging apparatus adapted to use a continuous tube of thermoplastic film comprising, in combination, driving means for advancing the tubular film along a predetermined path, control means linked to said driving means for halting the advance of said tubular film at predetermined intervals of film travel, sealing means for transversely sealing the thermoplastic tube while said film is stationary, cutting means for severing the tubular film parallel and in front of its forwardmost seal to form a bag blank sealed at one end while said film is stationary, conveying means adapted (1) to clamp said bag blank across its width adjacent the open end of said bag blank and (2) to force the open end of said bag blank against a projection to separate the parallel edges at the open end of said bag blank, a filling spout adapted to enter between said separated edges to permit materials to fill said bag blank and closing means for sealing the open end of the filled bag blank.
7. A bag forming and packaging apparatus adapted to use a continuous tube of thermoplastic film which comprises, in combination, sealing means for transversely sealing the thermoplastic tube at predetermined intervals along its length, driving means for advancing the tubular film along a predetermined path, cutting means for severing the tubular film parallel and adjacent each seal forming a bag blank sealed at one end, projection means for separating the parallel edges at the open end of said bag blank and conveying means for transporting said bag blank to a filling station.
8. A bag forming and packaging apparatus adapted to use a continuous tube of thermoplastic film which comprises, in combination, sealing means for transversely sealing the thermoplastic tube at predetermined intervals along its length, driving means for advancing the tubular film along a predetermined path, cutting means for severing the tubular film parallel and adjacent each seal forming a bag blank heat sealed at one end, projection means for separating the parallel edges at the open end of said bag blank, conveying means for transporting said bag blank to a filling station, filling means for charging the materials to be packaged into said bag blank, and closing means for sealing the open end of said charged bag blank.
References Cited by the Examiner UNITED STATES PATENTS 2,322,430 6/1943 Fay 53-179 2,576,542 11/1951 Schoen 53-29 2,612,738 10/1952 Salfisberg 53-29 2,643,496 6/1953 Cloud 53-183 2,649,671 8/1953 Bartelt 53-112 X 2,649,674 8/1953 Bartelt 53-183 2,754,644- 7/ 1956 Vergobbi et al. 53-29 2,929,180 3/1960 Abrams et a1. 53-29 FRANK E. BAILEY, Primary Examiner.
BERNARD STICKNEY, Examiner.
A. E. FOURNIER, S. ABEND, Assistant Examiners.