US2169173A - Process of sealing collapsible tubes - Google Patents

Description

Aug. 8, 1939 W/r/vEs s:

c. J. WESTIN 2,169,173

PROCESS OF SEALING COLLAPSIBLE TUBES Original Filed April 25, 1933 2 Sheets-Sheet l 8, 1939 c. J. wEsTm 2,169,173

PROCESS OF SEALING COLLAPSIBLE TUBES Original Filed April 25, 1933 2 Sheets-Sheet 2 and during the closing and'folding process.

Patented Aug. 8, 1939 PROCESS OF SEALING COLLAPSIBLE TUBES Charles J. Wcstin, Philadelphia, Pa., assignmto F. J. Stokes Machine Company, Philadelphia,

Pa., a corporation of Pennsylvania Application April 25, 1933, Serial No. 667,823-

Renewed April 2 193 7 9 Claims.

of collaps ble or flexible tubes used as dispensing containers for fluid or pasty materials, such as toilet creams, medicinal ointments, foods, extracts, etc. The tubes are usually made of some suitable soft metal or alloy, but may also be made of a flexible or resilient material such as cellulose, resinoids, or other synthetic compounds. Each tube comprises a body portion with a relatively thin wall and has one end formed into a neck having a discharge opening and provision for receiving a cap. The other end of the tube is left open until the tube is filled and then closed by means of folds and/or tucks made in the flattened out portion of the tube walls adjacent to the open end.

Heretofore, it has been the practice to rely on a closure made by folding and bending the flattened uncoated or dry end of the tube two, three or more times and in many different ways. An extra metal clip made from stiff material or additional folds or tucks has been resorted to in an attempt to guard against accidental openings or leaks. Attempts to prevent leaking have been made by precoatin'g the tube walls with latex or some anti-wetting material; or dipping the closure or molding or casting solder around the folds, etc. A number of the above methods which really did produce a perfectly tight closure have failed because they were either commercially impractical or economically prohibitive.

It is the purpose of this invention to provide methods and means for commercially producing a closure which will be air tight and have greater bursting strength than the present type of closures with which special reenforcing clips, extra folds, etc. are used. One of the greatest difllculties to guard against is the breathing action which takes place in changing temperatures with certain materials, and which causes the v,procluct to ferment or decay.

The methods here described and illustrated have been found through numerous tests and experiments to be commercially practical and produce the desired strength of closure, The process consists in applying cement, in suitable liquid or paste form, to the fold as the tube is ready to be filled or after the tubehas been filled As a particular type of cement suitable for this purpose, mention is made of that sold under the trade-mark Duco No. 5458.

The cement may be applied to the interior of the tube in a ring at the top or adjacent to the open end, either before or after filling the tube.

This invention relates to the closing and sealing The cement may also be applied to the tube fold as it is being closed or to that portion of the tube walls constituting the section used in the closure. If the cement is being applied at the time of the filling or closing, it is trapped inside and between the lapse of the folds while still in a fluid or plastic state, and as the folds are pressed together the cement is, of course, pressed into close contact with the tube walls as well as forced into every crevice and crack of the folds, It is evident that if sufllcient cement is applied, a certain portion will be squeezed out and form a cap around the edges and over the cracks of the seal. After the cement sets, which may be accomplished by allowing the tube to dry in the air, by applying heat, or by passing it through a drying chamber, a tight and very strong closure is produced.

The tubes are usually made of material of sufllcient stiffness so that the folds will retain their shape during the setting period. If, however, the material is flexible, means may be provided to hold the folds in close contact during the setting period or a quick-setting cement applied and/or heated pressing jaws used to instantly effect the setting,

It has been found in actual practice that tubes closed by the new process have a resistance against leaks as high as five times that of the best closure now commercially produced and the bursting strength approaches that of the strength of the tube walls. It is evident from the results obtained in actual practice with the new type of closure that a perfectly tight dispensing container is produced which satisfies the most exacting demands,

The danger of leaks at the discharge end must also be taken into consideration and guarded against; A proper type of gasket must be used and "maybe cemented in place with the same kind of cementand in a manner similar to that described for the closing and sealing of the open end. Thecement may be applied to the end of the nipple or the ,cement may be applied on the outside so as to'lill" thdrecess between the cap and the breast of the tube. It would be preferable, but may not always be practical, to use the type of tube known as a diaphragm tube which, of course, would furnish a perfectly tight tube at the discharge end,

In packaging perishable material it may be necessary to pass the filled tube through a processing chamber to expel the air. The method of closing can readily be adapted to such a process. If exhausting is desirable, the tubes may be passed through the processing chamber after filling and before closing, or the tube may be partly closed but not tight enough to prevent the exhausting, and then pass through the processing apparatus before the final cementing and closing is performed.

In actual practice I have found that this new type of closure permits the use of narrower folds resulting in a saving of /8 to in the length of the tube required in handling the same amount of material usually placed in a tube of a certain diameter and length. This means a considerable saving in tube material which will be a very desirable economy for large users of tubes.

For 'a further exposition of my invention reference may be had to the annexed drawings and specification at the end whereof my invention will be specifically pointed out and claimed.

In the drawings,

Fig. 1 is a diagrammatic view with parts in longitudinal cross section.

Fig. 2 is a diagrammatic view with parts in longitudinal cross section. I

Fig. 3 is a diagrammatic view with a portion of a tube shown in longitudinal cross section.

Fig. 4 is a diagrammatic view with a portion of a tube shown in transverse cross section.

- Figs. 5, 6 and 7 are diagrammatic views showing a portion of a tube in side elevation and illustrating steps of a process.

Fig. 8 is a longitudinal cross section through a seal at one end of a tube.

Fig. 9 is a diagrammatic view illustrating a modification.

Figs. 10, 11 and 12 are respectively a side, face and end view of a portion of a modified type of tube, and

Fig. 13 is a diagrammatic view showing a portion of a tube in longitudinal cross section.

Referring to the drawings:

Fig. 1 represents a standard tube having a thin walled body I terminating in a breast 2 which has a nipple for receiving a cap 3 which closes the discharge opening 5. To provide a proper seal, gasket I is inserted between cap 3 and the end of the nipple and a layer of cement may be applied between the gasket and the nipple to effect a tight seal as described above. This figure shows an empty tube having a ring of cement I applied by means of brush 6 adjacent to the end I on the interior walls of the open end.

Fig. 2 shows a filled tube of the type known as a diaphragm tube differing in construction from the one shown in Fig. 1 by having the discharge opening 9 closed by the diaphragm ill. The tubes are filled to a predetermined point I5, allowing sufficient space above the material for the required number of folds in makingthe closure. Ring 8 of cement is shown applied by a spray gun ll adjacent to the open end i.

Fig. 3 shows a part of a filled tube where the ring 8 of cement is being applied by means of a wiper or plunger i2, this plunger being so arranged that it may oscillate as well as rotate when applying the cement. Plunger I! may be round in outline and slightly smaller in outside diameter than the opening of the tube.

Fig. 4 shows a variation in the form of plunger or wiper for applying the cement internally. Instead of being round in outline as shown in a Fig. 3 the wiper shown in this figure is provided with pliable arms I! of suitable material fastened --to .a central axle i3 which-would oscillate into In applying the cement internally it is optional whether the tube is rotated against the means of applying the cement or the means are fastened to a holder which will rotate in applying the cement.

Fig. 5 shows a tube in the process of closing. The tube has been flattened and the first bend made to produce a fold in the wall. The fiat walls are bent at I! so that the end i6 forms an angle of approximately 45 degrees with the standing part I! on the tube. At this point in the process the cement may be applied as indicated by means of a spray gun or a brush 24. In machinery of the type used for filling and closing, the tubes are usually held in some sort of a conveyor and given an intermittent or step by step motion as they are conveyed from one station to another. The cement would be applied by placing the means for applying it at a point between two stations so that as the tube passes from one station to the other the cement would be sprayed or wiped onto the proper surfaces in the bend of the fold. It is evident that the means for applying the cement may be used as effectively in a machine operating on the continuous principle: i. e., where the tubes are con veyed at a constant, or practically constant, rate of speed instead of intermittently from station to station.

It should also be understood that the cement may be applied to the flattened walls of the tube to cover the desired space before the first bend in the flattened walls is begun, but it has been found preferable to apply it at the time in the process of folding shown in Figs. 5 and 7 in order to keep the cement from getting into the folding mechanism and gumming this up.

In Fig. 6 the tube is shown with the end l6 pressed tightly against the standing part i8. In some cases this may be considered a finished closure if one fold is found satisfactory for the strength required. Note that the cement is squeezed out to form a cap around the edges at l9.

Fig. 7 shows that it is customary to make two folds to produce a double closure in closing collapsible tubes and in this figure the fold produced in Fig. 6 has been bent down at so as to form an angle of 45 degrees similar to that of Fig. 5. The cement is shown as being applied by the means of a spray gun or brush 24 to the surface of i6 and 2! which will form the inside of the fold as it is finished by being pressed tight against the standing part of the tube.

Fig. 8 represents an enlarged section through a standard fold which has received a coating of cement internally as well as between each of the element folds. The results obtained by applying a sufficient amount of cement to the tube walls and pressing these tightly together is indicated by the cap formed at 22 as well as at 23.

Fig. 9 shows a different method of applying the cement to the bend of a tube in process of closing. A circular brush or wiper 25 is used and placed so as to apply cement to the proper faces of the fold. The flattened walls of the tube are bent at i! so that the end IE will form an angle of approximately 45 degrees with the standing part l8 of the tube. 'The wiper may be formed to fit into the angle formed by the bend in the tube wall and caused to rotate, it being mounted on a shaft supported on the machine and provided with means for rotating it. The brush or wiper 25 would mesh with a cement applying disk 26 which in turn might be dipping into a reservoir fllled with the cement. The tubes would receive their coatof cement as they are carried by the conveyor past the wiper.

Fig. 10 is a side view showing the finished closure and Fig. 11 a face or front elevation of a finished closure, while Fig. 12 represents the end elevation of the same. The caps formed by squeezing out the surplus of cement when the folds are pressed together, are indicated at 23 and 28. The closure may be left flat, as it is naturally formed by flat folder and closer jaws, or it may be corrugated or crimped as indicated in Figs. 11 and 12 at 30 and 3 I. The crimping of the fold has a very beneficial effect on the strength as it appears to closely knit the folds together. In addition to this it provides an ornamental effect to the otherwise flat and plain sides of the folds.

The advantages and benefits of proper crimping are described and claimed in my co-pendlng application, Serial No. 641,553, flied Nov. '7, 1932. It has been found that proper corrugation or crimping is of as great importance in tube closures produced by the cemented method as was described and claimed for tube closures made by the standard dry folds.

Fig. 13 shows a filled tube having the cement applied by means of a brush or spray gun 33 to the joint between the cap 3 and the breast 2, the cement being indicated at 32. It may be preferable to apply the cap seal before the tube is filled and at a time just after the cap is put in place by the capping machine and/or just as the tube is being ejected from the capping machine or transferred to the packing case.

While I have described and shown only two types of closure, that of a single fold in Fig. 6 and the double fold in Fig. 10, etc., I am not limiting myself to these two particular kinds, but it is evident that any type of closure including those having reverse bends or tucks may be greatly improved and strengthened by the method of cementing described in this invention. It would not present any serious difficulties to apply cement to the seal described and shown in Patent No. 1,852,225, granted to me on April 5, 1932, or any similar type of closures now in commercial use.

In certain cases it may be preferable to use a,

thermal cement (such as Duco No. 4620-Thermai Plastic Cement) for sealing the folds of the closure. The compositionof a cement of this character is disclosed in Patent No. 1,925,903 to Almon G. Hovey. This type ofcement may be applied either before filling the tube or after with the same method and in the same manner as described for ordinary cement and after or during the closing, sufficient heat applied to the closure by means of heated closing or crimping jaws to effect the fusing of the cement to permanently seal the closure. A similar tube and process of closing is described and claimed in my co-pending application Serial No. 561,111, filed September 4, 1931, now Patent Number 2,028,112 issued January 14, 1936.

I do not intend to be limited in the practice of my invention save as the scope of the prior art and of the attached claims may require.

I claim:

1. A process of sealing a collapsible, self-supporting tube which has been filled with the material it is to contain, which process consists in, coating the inner walls of the tube adjacent one end of said tube with a ring of cement, flattening the walls of said end of said tube into alignment Without a bellows fold between them, folding the terminal end of said flattened portion so that it forms an angle to the adjacent part of said flattened portion, applying cement in fluid state only to one side of the tube to the walls of the tube forming said angle, and bending said terminal end against the adjacent part of said flattened portion of the tube.

2. A process of sealing a collapsible, self-supporting tube which has been filled with the material it is to contain, which process consists in, coating the inner walls of said tube with a ring of cement adjacent one end of said tube, flattening the walls of said end of said tube into alignment without a bellows fold between them, exhausting air from said tube, folding the terminal end of said flattened portion so that it forms an angle to the adjacent part of said flattened portion, applying cement in fluid state only to one side of the tube to the walls of the tube forming said angle, and bending said terminal end against the adjacent part of said flattened portion.

3. A process of sealing a collapsible tube which has been fllled with the material it is to contain, which process consists'in, flattening the walls of the open end of the tube into alignment with each other without folds between said aligned walls, bending the terminal end of said flattened portion so that it forms an angle to the adjacent part of said flattened portion, applying cement only to the outer wall of the tube which forms the inside faces of the said angle, and further bending said terminal end of the tube against the adjacent flattened portion so as to bring the cement coated surfaces into intimate contact to form a cement sealed clipless closure.

4. A process of sealing a collapsible tube which has been filled with the material it is to contain, which process consists in, flattening the walls of the open end of the tube into alignment with each other without folds between said aligned walls, bending the terminal end of said flattened portion so that it forms an angle to the adjacent part of said flattened portion, applying cement only to the outer wall of the tube which forms the inside faces of the said angle, further bending said terminal end of the tube against the adjacent flattened portion so as to bring the cement coated surfaces into intimate contact to form a cement sealed clipless closure, and forming aligned indentations in the walls of said closure.

-5. A process of sealing a collapsible tube which has been filled with the material it is to contain, which process consists in, flattening the walls of the open end of the tube into alignment with each other without folds between said aligned walls, bending the terminal end of such flattened portion so that it forms an angle to the adjacent flattened portion of the tube, applying cement only to the outer wall of the tube forming the inside faces of said angle, bending said terminal end of said tube against the adjacent flattened portion to bring the cement coated surfaces into intimate contact to form a cement sealed fold, making a second bend in the flattened portion of the tube so that said first fold forms an angle with the flattened portion of the tube, applying cement only to the walls forming the inside faces of said angle, and bending said first fold against the adjacent flattened portion of the tube to bring the cement coated surfaces into intimate contact to form a cement sealed clipless closure.

6. A process of sealing a collapsible tube which has been filled with the material it is to contain, which process consists in, flattening the walls of the open end of the tube into alignment with each other without folds between said aligned walls. bending the terminal end of such flattened portion so that it forms an angle to the adjacent flattened. portion of the tube, applying cement only to the outer wall of the tube forming the inside faces of said angle, bending said terminal end of said tube against the adjacent flattened portion to bring the cement coated surfaces into intimate contact to form a cement sealed fold, making a second bend in the flattened portion of the tube so that said first fold forms an angle with the flattened portion of the tube, applying cement only to the walls forming the inside faces of said angle, bending said first fold against the adjacent flattened portion of the tube to bring the cement coated surfaces into intimate contact to form a cement sealed clipless closure, and forming aligned indentations in the walls of said closure.

7. A shipping and dispensing container for plastic acidic materials comprising a collapsible tube terminating at one end in a thickened neck portion provided with a central dispensing bore, a cap member detachably secured to the end of said tube neck, closing said bore, and a thin brittle film of synthetic resinous material adhesively bonded to the inner surface of said cap and said neck, hermetically sealing said parts, said resinous material being of an acid-resistant character insoluble in the contents to be packaged.

8. A closure and seal for the discharge opening of a collapsible tube comprising, a collapsible tube having a thin-walled body, a nipple on said body having a discharge opening therethrough, a cap, interengaging securing means removably attaching said cap to said nipple, and a layer of cement applied to said nipple so as to eifecta tight seal for said discharge opening and enclosed by said cap and said nipple.

9. A collapsible tube for packaging fluids comprising, a body portion having a thin wall, a thick-walled portion'of said tube having a dis.- charge opening therethrough, a flanged cap fitting over and interengaging with an outer surface of said thick-walled portion so that said cap surrounds the outlet of said discharge opening, and cement lying within the flange of said cap andconnected to said thick-walled portion to seal the outlet of said discharge opening.

CHARLES J. WESTIN.

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