US2319234A - Method of sealing containers - Google Patents

Description

Patented May 18, 1943 UNlTED STATES PATENT OFFlCEifi i John M. Hothersall, Brooklyn, N. Y., assignor to American Can Company, New York, N. Y., a corporation of New Jersey Application May 5, 1939, Serial No. 272,059

7 Claims.

The present invention relates to a method of sealing a container or can having a vent hole and has particular reference to sealing such a vent hole with a rubber plug or thelike.

In the packaging of certainikinds of products in cans the filled can is preferably closed with a cover having a small vent hole. Such a vent hole is provided so that the interior of the can may be vacuumized or vacuumized and gassed under pressure. After this closing, however, the vent hole must be sealed and the present invention contemplates a method of sealing the hole with a rubber plug.

An object therefore of the invention is the provision of a method of sealing a vent hole in a closed can wherein a rubber plug is first compressed into a dimension less than the diameter of the vent hole and is then inserted into the hole after which it expands to its original size completely filling and hermetically sealing the hole.

Another object isthe provision of such a method wherein the sealing plug is cut from a string of rubber and is forced into sealing position in the hole to be sealed by pressure exerted through another plug disposed adjacent to it and in end to end relation.

Another object is the provision of a method of this character wherein the can to be sealed with a plug is vacuumized or is vacuumized and gassed prior to the insertion of theplug. I

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken drawing, discloses a preferred embodiment thereof.

Referring to the drawing:

Figure 1 is a sectional view of'an apparatus adapted to seal cans in accordance with the steps embodying the instant method invention, the view showing the upper end of a can in place to be sealed, the can being shown in section; and

Figs. 2, 3 and 4 are enlarged fragmentary sectional views of parts of the apparatus and of the upper part of a can and illustrating the steps of sealing the latter.

As a preferred embodiment of the'invention the drawing illustrates a sheet metal can Awhich is adapted to be sealed with a rubber plug B. The can A includes a body C which is closed with a top closure or cover D secured in place by a suitable seam E. The cover is provided with a depressed panefF in which there is formed a vent hole G which passesthrough the cover-wall.

in connection with the accompanyingv It is this vent hole which is hermetically sealed with the rubber plug B.

The plug B is preferably cylindrical in shape and is cut from a round string H of solid rubber. The cut plug is carried to a position in vertical alignment with the vent hole in the can A and then a second plug is preferably cut oil and placed on top of the first plug in readiness for sealing the can. 1

The interior of the can A is then preferably vacuumized through the vent hole G and the 'air free space thus created may be refilled through the vent hole with an inert gas such as'carbon dioxide or the like. After such a vacuumizing and gassing operation the rubber plug is inserted into the hole.

The lowermost plug 3 of the two arranged in end-to-en-d relation is compressed into a dimension smaller than that of the vent hole G by an end pressure applied to itthrough and longi tudinally of the second plug. The compressed plug is then brought into position adjacent'the hole and is pushed therein for a distance of approximately one half its length. The released part of the plug which extends inside of the can and below the wall surrounding the hole immediately expands to its original size. The end pressure on the plug is then removed and the compressing action on that portion of the plug extending outside of the can is terminated and this released part of the plug then also expands into its original size. Thus the inserted plug fully fills the hole and extends on both sides providing.

'the can. It is also provided with a resilient rubber ring [3 secured in an annular groove 14 adjacent the inner face of the flange. This'gask'et element is brought into engagementwith the "can seam E when the plate is on the can and seals offthe space above the can from the outside atmosphere. In this position of the plate H on the can, there is a space between it and the can top D so that vacuumizing and gassing of the can interior through the vent hole G may be more readily effected. Air withdrawn from the canin vacuumizing is preferably brought through a passageway lfilocated in ailarge boss ll. formed-integrally with the plate ll. One end of the passageway communicates with the space between the plate and the can and the opposite end with a pipe I8 which leads to any suitable vacuumized or vacuumizing element such as a tank or pump. This pipe is threaded into the side of the boss II. A valve I!) may be provided in the vacuum pipe line for controlling the vacuum.

When'gassing of the vacuumized can is desired such gassing may be effected by way of a channel 21 which is also formed in the boss I! adjacent the vacuum passageway l6.

One end of this channel communicates with the'space."

between the plate and the can. Its opposite end. communicates with a pipe 22 which leads from a suitable source of gas. The pipe is threaded into the side of the boss I! and a valve 23 in this pipe line allows for control of the flow of l gas therethrough. The rubber string H from which the plug B is .cut is preferably disposed in a vertical bore 25 formed in the plate boss. H. The lower end of the string at periodical intervals extends down .into a pocket 26 of a rotatable transfer disc 21 disposed in a horizontal slot 28 formed in the plate boss. end of a vertical shaft 29 carried in the boss. The upper end of the shaft extends above the boss and is provided with a handle 3i which may be used for rotating the disc as hereinafter described. .-I The rubber string is fed into the pocket 26 of the disc 21 by a pair of grooved friction rollers mounted on short shafts 36 carried in a bracket .31 formed on the plate boss l'l.

keyed to one of the roller shafts provides means for. rotating the rollers.

. Adjacent the lower end of the rubber string H there is disposed a cutter 4| which is adapted to move in a slideway 42 formed in the plate boss ill .just above the upper surface of the disc 21. A

handle 43 formed on thecutter provides means for pushing the cutter inwardly against the rub- }ber. string H so that itsevers that portion of the string which extends down into the disc pocket 26. It is this portion when cut off that constitutes the rubber plug B.

The cut plug B is transferred from its position adjacent the cutter 4| by a rotation of the disc ;21, this rotation bringing the plug into the center of the plate II where it is directly over the .vent hole G in the can.

Insertion of the plug B into the vent hole G is effected by a vertical plunger 45 which is car ,riedin a sleeve 4'! mounted in a bore 48 formed in-ithe plate 11. 'The plunger is movable relative-to the sleeve 41 and is provided with an enlarged operating head or handle 49. It also ,supports a compression spring 5-l interposed between the head and-the top edge of the sleeve.

The sleeve 41 is also movable in its bore 48 .and is provided at its upper end with operating elements, in this case, handles 53. This sleeve is enlarged in an annular shoulder 54 which is normally maintained in engagement with a shoulder 55 formed in the plate boss l'l, adjacent the upper end of the bore 48. The sleeve is retained in this position by a compression spring 51 which vsurrounds the sleeve and is interposed between the sleeve shoulder 54 and a segmental collar 58 which is disposed in the lower end of the bore :and'is secured by screws 59 to the plate I I; This collar also serves as a bearing guide for the lower end of the sleeve.

The disc is mounted on the lower A handle 38 a -r-iIn the region of the rubber plug transfer disc 17.5

21, the sleeve 41 is cut away in a horizontal clearance recess 62. The disc extends into this recess and thus provides for proper positioning of the plug B centrally of the plunger 45 and the sleeve. At its lower end, the sleeve is reduced in diameter as at 63, this end being slightly smaller than the area of the panel F of the can cover.

This reduced section is cut through longitudinally with a plug confining bore 64 which is slightly smaller in diameter than the vent hole G of the can. In length the bore 84 extends for a distance substantially equal to one half the length of the cut rubber plug B. At its upper end, this bore flares out into a bore which is a-lower continuation of the plunger bore.

When the plug Bin the transfer disc pocket 26 is in vertical alignment with the plunger 45, it is also aligned with the vent hole and while so located, pressure is applied on the plunger from 0 above. In other words the plunger is moved down thereby pushing'the plug B out of its pocket and forcing it down into the bore' 65. The lower lend of the plug is forced into thebore 64. and is thus compressed. Upon, release of pressure, the plunger ascending under the action of the, spring -5l, returns to its original elevated position..

Another plug B is then cut from the string H and is transferred, by rotation ofthe disc 21,.into aligned position above the. plug then held in the sleeve 47. The sleeve v4'! isnow moved down until its lower end 63 strikes against the can wall of the panel F, as shown inF-ig. 2. The sleeve is held tightly against the can wall while, the plunger 45 is again depressed.

This time the plunger moves the second plug B out of its disc pocket 2-8 and down against the first plug in the bores 65, 64. This forces the first plug out of the upper bore 65, as the upper plug enters, and presses ittinto the vent hole G of the can. The plug having been compressed in the bore 64 into a diameter smaller than the vent hole, it thus readily passes into the hole. The part of the; plug in thehole, andthe part extending below, being released. from the confinement of the lower bore 54 immediately expands to its original size as shown in Fig. '3.

Substantially one half of the first or lower plug is forced outof the sleeve bore 54 in this manner before the spring 57 returns the sleeve into its original upper-position. During this raising of the sleeve, pressureis maintained on the plunger .45 and this pressure, effective through the second =plug, now forces thefirst plug entirely out of the rising sleeve-bore 64.- Simultaneously the second :plug is brought into the bore 64 as shown in Fig.

,4. The plunger is then released and returns to its original level.

Forcing of the first plug B out'of thesleeve bore 64. during the operation just described-,p'ermits that-portion just released, i. e., thepart abovethe can cover, to also expand into" its original size. The inserted plug thus completely fills the vent hole .G and provides a hermeticzseal .for the can. The expanded portions ofthe'plu on each side of the can wall provides flanges and prevent its scribed being merely a preferred embodiment thereof.

I claim:

1. A method of sealing a closed container having a vent hole, which comprises moving a resilient plug and said hole into alignment, compressing the inner portion of said plug into a dimension smaller than the hole to be closed, moving a second plug into alignment with said partially compressed plug, forcing the compressed inner portion of said first mentioned plug into said hole by pressure applied on said second plu while simultaneously compressing the outer portion of said first mentioned plug and also compressing the inner portion of said second plug to provide a greater pressure on said first mentioned plug being inserted by the application of the pressure to an uncompressed portion of the second plug, and then stripping the compressed outer portion of the first mentioned inserted plug from the compressing medium to allow said compressed outer portion to expand over and hermetically seal the hole.

2. A method of sealing a closed container having a vent hole therein, which comprises cutting off a portion of a solid rubber string to constitute a plug, moving said plug into alignment with said hole, compressing a portion of said plug into a dimension smaller than the hole to be closed while maintaining said plug in axial registry with and spaced out of contact with the latter, bodily moving said partially compressed plug to dispose its compressed portion in immediate proximity to said hole, and then inserting said compressed plug portion into the hole to permit the same to expand and hermetically seal the hole.

3. A method of sealing a closed can having a vent hole therein, which comprises providing a plurality of rubber plugs arranged in end to end abutting relation, moving said plugs successively into registry with cans to be sealed, compressing a said plug into a dimension smaller than the hole to be closed by exerting a pressure on the same through a succeeding plug, bodily moving said compressed plug axially and without further compression into immediate proximity to said hole in axial alignment therewith, forcing the inner compressed portion of said plug into said hole, and releasing said pressure whereupon the compressed inserted plug expands and hermetically seals the hole.

4. A method of vacuumizing and sealing closed containers each having a vent hole in the closure thereof, which comprises vacuumizing said containers through such vent holes, successively moving a plurality of resilient plug elements into registry with said vent holes of containers to be sealed, compressing a said rubber plug into a dimension smaller than the hole to be closed, bodily moving said compressed plug axially and without further compression into immediate proximity to said hole in axial alignment therewitln 5. A method of vacuumizing, gassing and sealing a closed container having a vent hole in the closure thereof, which comprises vacuumizing a container through said hole, filling the vacuumized container with a gaseous fluid under pressure, moving a resilient closing plug into registry with a said vent hole of a container to be sealed, compressing the inner portion of said plug into a dimension smaller than the hole to be closed, bodily moving said compressed plug axially and without further compression into immediate proximity to said hole in axial alignment therewith, and inserting said compressed plug portion into the hole to permit immediate expansion thereof to hermetically seal the hole.

6. A method of sealing a container having a vent hole therein, which comprises providing a rubber plug, confining the plug in a holder, compressing the inner portion of the confined plug within the holder into a dimension smaller than the hole to be closed, bodily moving the holder into engagement with the container with the inner compressed portion of said plug disposed in alignment with and immediate proximity to the hole, ejecting the compressed portion of the confined plug from the holder and into the hole, to permit the released compressed inner portion of the plug to expand around the hole on the inner free side thereof while simultaneously compressing the remaining outer portion of the plug Within said holder, and then removing the holder from engagement with the container to strip the said remaining compressed portion of the partially inserted plug therefrom so as to permit said stripped compressed portion to expand around the hole on the exterior side thereof whereupon the plug fills and hermetically seals the hole.

7. A method of sealing a container having a vent hole therein, which comprises providing a plurality of rubber plugs, confining the plugs in a holder, compressing the inner portion of one of the confined plugs within the holder into a lateral dimension smaller than the hole to be closed by exerting a longitudinal pressure on it through another and succeeding plug, bodily moving the holder into engagement with the container with the inner compressed portion of the plug disposed in alignment with and immediate proximity to the hole, ejecting said compressed portion of the confined plug from the holder by longitudinal pressure exerted thereon through a succeeding plug to insert said compressed plug portion into the hole to permit, said ejected compressed plug portion to expand around the hole on the inner free side thereof, while simultaneously compressing the remaining outer portion of the partially inserted plug within said holder, and then removing the holder from engagement with the container while maintaining the pressure on the plug to strip the remaining last compressed portion of the partially inserted plug to permit such portion to expand around the hole on the outer side thereof, whereby the plug fills and hermetically seals the hole.

JOHN M. HOTHERSALL.

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