US3369340A - Apparatus for sealing containers - Google Patents

Description

Feb. 20, 1968 F. M. KELLY 3,369,340

APPARATUS FOR SEALING CONTAINERS Filed April 29, 1965 2 Sheets-v-Sheet 1 INVENTOR FRANK M. KELL Y A Horney F. M. KELLY APPARATUS FOR SEALING CONTAINERS Feb. 20, 1968 2 Sheets-Sheet Filed April 29, 1965 INVENTOR. FRANK M. KELL Y A I rarney United States Patent 3,369,340 APPARATUS FOR SEALING CONTAHVERS Frank M. Kelly, Richmond, Ind., assignor to Aluminum Company of America, Pittsburgh, Pa., a corporation of Pennsylvania Filed Apr. 29, 1965, Ser. No. 451,709

1 Claim. (Cl. 53-109) ABSTRACT OF THE DISCLOSURE A method of vacuumizing and sealing containers by frictionally engaging a closure loosely fitted on a container with a pressure block, raising the block and frictionally engaged closure, injecting gas beneath the closure, lowering the block and frictionally engaged closure to seal the container, reforming the closure about the container mouth, securing the closure to the container, and removing the sealed container from the pressure block.

This invention relates to a method and apparatus for sealing containers and, more particularly, to a method and apparatus for producing vacuum sealed containers.

It is common practice in vacuum packaging to place a closure loosely upon a container having contents filled to a predetermined level. The closure is then raised in order to allow a hot gas such as steam, to displace the air in the head space of the container, and subsequently the closure is replaced on the container and sealed thereto. As the temperature of the sealed container is reduced, a vacuum is established.

Various means have been employed to raise the loosely fitted closure to permit the introduction of gas or steam prior to replacing the closure and sealing the container. Some systems employ the pressure of the gas or steam to raise the closure. For ferrous closures, magnets have been employed. Limited control of the closure and other inherent limitations in these systems often make them unsatisfactory, if not quite unuseable.

It is an object of this invention to provide an improved method and apparatus for mechanically lifting a closure from a container, to permit the introduction of inert gas or steam, and mechanically replacing the closure afterward.

It is an object of this invention to provide an improved apparatus for mechanically controlling a closure during a gas or steam insertion stage of packaging and also for reforming the closure to conform to the container mouth.

It is another object of this invention to provide apparatus which in addition to facilitating the aforementioned objectives, serves to mechanically restrain the closure on the container while the closure is secured thereto.

These and other objects and advantages of the invention will be understood from the following description of the invention, on reference to the illustration appended hereto in which:

FIG. 1 is an enlarged sectional view of a sealing unit adapted to be used with this invention;

FIG. 2 is an enlarged sectional view of a pressure block about to engage a closure loosely fitted on a container;

FIG. 3 is similar to FIG. 2 but shows the pressure block in engagement with the closure;

FIG. 4 is a similar view of the pressure block holding the closure above the container while steam is introduced;

FIG. 5 is a similar view of the closure reseated on the container and reformed thereon by the pressure block;

FIG. 6 is an enlarged section of the holding and reforming pressure block employed as part of the sealing unit shown in FIG. 1.

In high speed vacuum packaging machinery, it is generally necessary to first fill a container and then loosely apply a closure. 'In order to obtain a vacuum S6Ell,ill is then necessary to lift the loosely applied closure from the ,container for the introduction of a hot gas, which may be an inert gas .or steam. As this is required regardless of whether the translational path of the container is circular, elliptical or straight, reference will be made to a rotary machine such as that disclosed in United States Patent No. 3,191,352.

FIG. 1 shows a single sealing unit suitable for use in accordance with this invention. The sealing head 6 houses a pressure block 3 and knock-out plunger 4. The lower portion of the pressure block has an annular wall 8 in which a substantially cylindrical closure-receiving orifice 12 is formed and within which the knock-out plunger 4 is movable. The lower portion of the wall 8 is undercut to provide an interior annular concave surface 9 bounded at the bottom by end 10 of end wall 8 and at the top by lower end 11 of the interior wall 8, small corner fillets being provided at both of the ends thereof. The portion of the orifice 12 defined by the concave surface 9 is nearly the same in size as the portion of the closure to be received therein. It is, however, slightly smaller than the closure, in order to frictionally engage and hold the closure. In fact, as the portion of the closure so engaged will be reformed at a later step in the process, the difference in dimensions may be such that the closure is deformed radially inwardly upon engagement by the surface 9 of pressure block 3.

As is normal in the operation of vacuum packaging machines, FIG. 1 shows a container 1, supported on a container pedestal 7, with a closure 2 loosely applied thereto, being brought under a sealing head 6. The pressure block 3 which is centered over the container and closure is lowered to the position shown in FIG. 2, with the lower edge of the knock-out plunger 4 being above the corner intersection of surface 9 and wall 8 at location 11. As is shown in FIG. 3, continued downward movement of the pressure block results: in the concave surface 9 coming into frictional engagement with the closure 2. To insure firm frictional engagement, it is preferahle to provide a closure of slightly larger exterior size than the interior size of concave surface 9. The pressure block 3 is then raised with the frictionally engaged closure 2 being lifted from the container ll. While the closure is in this position, gas is introduced into the container head space, between and underside of the closure and the container mouth, through gas channels 5. With the next downward movement, the pressure block 3 replaces the closure on the mouth of the container and continues downward beyond the position shown in FIG. 3 to reform the closure, compressing the closure gasket 17 and deforming the closure skirt 16 and panel 15 to conform the same to the container mouth finish, as illustrated in FIG. 5. This establishes a seal on the top of the container mouth as well as the outside thereof. During this operation, corner 11 and concave surface 9' bear on the upper part of the closure skirt 16. In order to facilitate reforming, the diameter of the orifice at corner 11 is less than the diameter of the orifice at lower corner 10. To provide adequate clearance, the diameter at corner 11 should be greater than the exterior diameter of the container at the container mouth. The bottom of the knock-out plunger 4 bears on the closure panel 15. While the closure is restrained in this fashion, it is secured to the container by thread rolling dies 13 (FIG. 1), which form threads in the closure skirt 16. The sealed container is then released by raising the pressure block 3 while maintaining the position of the knock-out plunger 4 in bearing relationship wit-h the closure panel 15 until the pressure block 3 is out of contact with the closure, and subsequently raising the knock-out plunger. Thus, the uniquely designed pressure block of this invention permits positive mechanical raising of a closure during the purging operation and subsequent reseating of the closure with contemporaneous reforming of same to conform to the configuration of the container finish. While the closure is restrained in this position, threads may be placed in the closure skirt. It will be appreciated that complete control of the closure is maintained from the time of initial frictional engagement by the pressure block 3 until the container is fully sealed.

Applicants pressure block thus permits firm mechanical engagement with a closure and, where desired, reforming of the closure. Reforming the closure while it is on the container produces a tight seal which can compensate for container imperfections without reducing production speeds. In addition the pressure block design facilitates hold down of the closure during the sealing or thread rolling stage.

While for purposes of illustration specific reference has been made to containers being sealed by means of threaded closures, the invention is equally applicable to lug type or press-on type closures. A lug type closure might be secured to a container in a manner similar to that employed with threaded closures. With respect to press-on type closures the downward force of the pressure block, with or without reforming, may be employed to secure the closure and seal the container.

While a glass container and metal closure have been selected for purposes of illustration, the selection of materials is in no manner critical to the invention, and the containers and closures may be made of numerous suitable materials. The containers may conveniently be made of glass, plastic, metal or other substantially rigid material. The closures might be made of plastic or metal, such as tin plate or aluminum, for example.

In order to facilitate smooth engagement and disengagement of the closure by the pressure block, it is preferable to have the concave surface 9 meet the pressure block bottom 14 in a fillet that is generally curved as at 10. This also serves to avoid damage to the closures decorative finish. Where reforming is desired, corner 11 should also be filleted or curved so that the downward movement of the pressure block to reach the position shown in FIG. 5 does not mar the decorative finish of the closure.

While for purposes of illustration, a container having a vertical external wall at the container mouth has been shown, the invention is not so limited. If the container Whereas particular embodiments of the invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details may be made without departing from the spirit and scope of the invention as set forth in the appended claim.

I claim: I

1. A method of vacuumizing and sealing containers which comprises:

(a) delivering a container with a loosely fitted closure over the mouth thereof into alignment with a sealing head having a pressure block;

(b) lowering said pressure block to frictionally engage said closure;

(0) raising said pressure block to lift said closure from contact with said container mouth;

(d) injecting gas between the container mouth and underside of said closure;

(e) lowering said pressure block to reseat said closure on the mouth of said container and establish a seal;

(f) reforming said closure to conform to the container mouth prior to securing said closure to said container;

(g) securing said closure to said container; and

(h) removing the sealed container from the pressure block.

References Cited UNITED STATES PATENTS 1,244,494 10/1917 Hammer 53-341 2,472,664 6/1949 Krueger 5310 1 X 2,578,815 12/1951 Kronquest 53109 X 2,995,882 8/1961 Barnby 53-109 X 3,039,247 6/1962 Thomas et al. 53-42 1,913,177 6/1933 Underwood. 2,017,766 10/1935 Mullen. 2,198,589 4/1940 Bell. 2,337,170 12/1943 Wareham.

TRAVIS S. MCGEHEE, Primary Examiner.

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