US1935100A - Collapsible tube and cap assembly and method of effecting the same - Google Patents

Description

Nov. 14, 1933; A. w. PAULL El AL COLLAPS IBLE TUBE AND CAP ASSEMBLY AND METHOD OF EFFECTING THE SAME Filed Dec. 24, 1952 Patented Nov. 14, 1933 UNITED STATES PATENT OFFICE Archibald W. Paull and John A. McGinnis, Wheeling, W. Va., assignors to Wheeling Stamping Company, Wheeling, W. Va., a corporation of West Virginia Application December 24, 1932 Serial No. 648,816

3 Claims.

This invention relates to containers and closures therefor, and more particularly to containers formed of extruded soft metal such as are commonly used for tooth paste, shaving cream,

5 and the like, and which are referred to generally as collapsible tubes.

The ordinary collapsible tube comprises an elongated tubular body of a thin flexible nature terminating at one end in-a shoulder which has a threaded neck of smaller diameter than the tube projecting therefrom, the shoulder and neck being relatively heavier so as to resist distortion. The neck is externally threaded, and is closed by a cap which is screwed onto the threaded neck and which usually has a cork liner in order to efiectively seal the tube. These tubes are usually filled under pressure by filling machines from the end of the tube opposite the capped end, the large end of the tube subsequently being sealed, and

it is very important in this filling operation that the cap shall be quite tight, as otherwise the contents of the tube leak out around the cap and spoil not only the appearance of a particular container where the cap is loose, but deposit -material on the filling machine which subsequently is transferred to other tubes in the process of filling, necessitating that the machine be stopped. The constituents of such tubes, moreover, are frequently of an extremely oily nature,

or other volatile constituents, either of which have to be tightly sealed.

For this reason it has heretofore been considered necessary to provide a cork in the caps for such tubes, this corking operation being a separate manufacturing step in the making of the cap, and the caps have to be tightly screwed onto the tubes in order that the cork'will be forced tightly against the end of -the tube and prevent leakage. I a

In the formation of such tubes the tube is first extruded from a blank without threads on J the exterior of the neck and without the passage way through the neck being open at the .end of the tube. The tube is subsequently trimmed to remove metal from the end of the tube to open up the passageway through which end the neck is threaded. According to the present invention, the tube is made in the usual way through the step of trimming and threading the neck.

The present invention, however, contemplates the use of a special cap having an outer portion which engages the threaded neck of the tube, and an inner portion which enters the opening in the neck of the tube and is forced by deforming the metal in the neck into a tight sealing relation with the metal, eliminating any requirement for cork in the cap. Preferably the interior plug is threaded, and the application of the cap to the tube causes a thread to be cut by such plug on the interior of the tube. Since the chasing of the 60 thread on the inside of the neck is effected by the application of the cap to the outside of the tube, the threads on the inside and outside of the neck stay in proper relation to one another, and the use of delicately adjusted machinery for simultaneously chasing the threads on the inside and outside of the neck is eliminated, and there does not have to be any special relation between the point where the thread for that portion of the cap which engages the outside of the neck begins with reference to the point where the thread on the plug portion of the cap begins. Furthermore, by causing the thread on the plug to chase its own thread on the inside'of theneck, a closer and more effective sealing is secured than if the thread on the inside of the tube were independently chased. I

The invention may be readily understood by reference to the accompanying drawing, in which:

Figure 1 represents a longitudinal section of a collapsibles tube after .it has been extruded and before it'has been trimmed or threaded;

Figure 2 is a similar view representing a section through the tube after it has been trimmed and the outside of the neck threaded;

Figure 3 is a view similar to Fig. 2 after the cap has been applied to the tube;

Figure 4 is a view similar to Fig. 3 showing the manner in which the interior of the neck has been threaded by the application of the cap, the cap being removed in Fig. 4; and v Figure 5 is a section through the cap separate from the tube.

Referring to Fig. 5, the cap is of the conventional shape, comprising a body 2 having a laterally projecting fiange portion} which can be conveniently gripped, and a skirt portion 4 which is internally threaded for application to the threads on the neck of a collapsible tube. Centrally positioned inside the skirt 4, and formed integrally with the body of. the cap, is a central plug 5, this plug preferably being shaped in such a way that when the cap is screwed onto the neck of the tube the plug will force itself into seating relation or sealing relation with the soft metal forming the interior of the neck of the tube. Preferably, the plug has external threads 6 for effecting this result. The cap may be formed of the same material as the tube, that is,

' a1 bran new tin and antimonypor inthe ufacture of collapsible tubes, in that preferably, it is formed'of bakelite or some other the thread on the inside 02 the neck is simul-= terial slightly harder than the material of: taneously efiected with the application of the which the tube is formed. cap to the tube, and the thread on the exterior Referring to Fig.1, thecollapsible tube is first or the neck provides .the lead through which the formed with an extruded thin ductile body I havplugbn the interior of the -cap cuts the threads in in a heavier shoulder portion 8 and a neck porproper relation to the threads on the exterior of tion' 9, the end of the passageway through the the tube. A neck being sealed as indicated at $10. The caps, particularly it formed of bakelite, In the usual course of manufacture, which is can be cheaply molded with the threads on them, followed withthe present invention, the end of as will be readily understood by those skilledin the tube is trimmed to remove the obstruction the artoi working bakeli and the cap ischeaper l0, and a thread 11 is rolled or otherwise "chased to manufacture and r uires fewer operations onto the, exterior of the neck. The cap 2 is then than the ordinary cap now commonly provided in applied to the neckf- The skirt portion 4 is which a cork insert is positioned on the inside of longer than the plug portiont, so that the thread the cap.v At the same time, the cap forms a more on theskirt starts to engage the thread on,the emcient seal,flrst, because it does not have neck before the plug enters the passage in the to: be screwed fully home in order to eii'ec neckof the tube. Howev'en'asthe cap is screwed seal the end of the tube; and secondly, because home, the Pl turning and forcingits way down there is an actual interfitting of the sealing parts into the neck of the tube is brought into a tight of the cap and tubewhich prevents leakage of sealing relation with the interior of the neck the contents of the tube.

of the tube. For instance, by usingthreads as i We claim: v

indicated at 6, these threads cut a shallow thread 1.- The combination with a collapsible. tube on the inside of the neck of thetube by means ,formed of a soft pliable metal and having an ex- 109 of which a very tight'and effective sealing relateriorly threaded neck, of a cap having an in tion .between'the tube and the cap is brought teriorly threaded skirt" engagin the threaded a about, and sealing relation exists even neck of the tube and having a central plug elethoughthe cap should not be turned all-the way ment of less length than the skirt and adapted to m will'he seen from the ioregoing'descripm home onthe threaded neck. When the cap is enter the neck of the tube, said plug having removed, as shown in 5, the interior. of'the" threads on the exterior thereof, the diameter or 'neck'will disclose the shallowthread which has the plug being such that the threads on the exbeenc'ut orchased into it by the plug portion 5 terior thereof will chase threads onthe interior of thecap. I v oi the neck of the tube.

As hereinbefore indicated, since the thread on the inside of the neck is formed by the applicaformed of asbft pliable metal and having an extion 'of the cap to the threaded exterior of the terio'rly threaded neck, of a "cap of relatively tube, the" threads onthe inside and outside al-" hardermaterial having an interiorly threaded ways bear the pr per relation with, respect to engaging the threaded neck or the tube and 'each other and withrespect to the threads on the having a central plug element thereon adapted t6 portions 4 and 5 0f that particular, cap; More-- enter the neck of the tube, said central plug beover, by forming the thread on the inside of the ing externally threaded and adapted to ce tube by the action of the plug 5, a tighter seal is threads. on the interior of the neck of the tube obtained than: ii. the thread'were independentlyw whenthe cap is screwed onto the tube. formed on .the inside of the neck. "By having a 3. The combination with a collapsible tube 12g cap which is of slightly harder material than the formed of a soft pliable metal and having an exmetal of whichth tube is formed, a thread is teriorly threaded neck, of a cap of relatively cut into the inside of the neck more efiectively harder material having an interiorly threaded than where the plug is of asofjt meta-Land the skirt engaging the threaded neck of the tube and. threads 6 could be mutilated, although our inhaving a central plug element thereon adapted vention contemplates either arrangement. Obvi to enter the neck of the-tube, said central plug ously, alsb, instead of forming threads on the being externally threaded-and-adapted to chase .inside'of the. neck of the tube, the plug nay disthreads on the interior of the neck of the tube place the soft metal'of-vthe. neck of the tube in when the cap is screwed onto the tube, the plug other ways to efiect a tight-seal, although a thread. being of less length than the 'interlorly threaded 134} is obviously preferable because of the tighter seal smrt. V whichiteflects.

um, inveniidn contemplates a new pd 2.- The combination with a collapsibleztube 1m

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