US2898974A - Apparatus for heat-sealing metallic liners in containers - Google Patents

Description

Aug. 11, 1959. 2,898,974

G METALLIC LINERS IN CONTAINERS J. 5. WILSON APPARATUS FOR HEAT-SEALIN FiledMay 28, 1957 2 Sheets-Sheet 1 5 & v w

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. ATTORNEYS APPARATUS FOR HEAT-SEALING METALLIC LINERS IN CONTAINERS Filed May 28. 1957 J; B. WILSON Aug. 11, 1959 2 Sheets-Sheet 2 INVENTOR JOHN B. W/LSO/V BY I ATTORNEYS United States Patent APPARATUS FOR HEAT-SEALING METALLIC LINERS IN CONTAINERS John B. Wilson, Louisville, Ky., ,assign'or to Reynolds Metals Company, Richmond, Va., a corporation of Delaware Application May 28, 1957, Serial No. 662,140 9 Claims. (Cl. 154- 1) installing of the liner.

While various forms of apparatus have been employed heretofore for heat-sealing particular non-metallic liners to the interior of containers by employment of both heat and pressure, difficulty has been encountered when attempting ,to use such apparatus for securing metallic liners in those containers. Such diiliculties frequently include the galling of the thin metallic surface when removed from pressure contact with a heated metallic mandrel, the non-uniformity of the seal of the liner to itself, or of the liner to the container wall, and the wrinkling of the liner during the sealing operation. It is these and similar disadvantages of the known procedures which it is a purpose of my invention to overcome.

An object of the invention is to provide an improved apparatus for securing a metallic liner preform to a container.

Another object is to provide an improved apparatus for applying sealing pressureto a metallic liner preform disposed in contact vwith the interior of a container.

Another object is to provide an improved heat-sealing mandrel incorporating a means for stripping a lined container therefrom.

A further object is to provide an improved means for actuating a movable heat-sealing mandrel and for automatically retracting the, mandrel to a container receiving and discharging position.

Other objects and advantages will become apparent as the description proceeds and when considered in conjunction with .the accompanying drawings in which:

Fig. l is a perspective view of one form of heat-sealing apparatus in normal position prior to use;

Fig. 2 is a diagrammatic view showing a liner preform in position upon the mandrel;

Fig. 3 is a diagrammatic view showing the liner preform and container in position upon the mandrel;

Fig. 4 is a longitudinal sectional view through the mandrel;

Fig. 5 is a sectional view on line 55 of Fig. 4;

Fig. 6 is a perspective view of the apparatus at an intermediate stage of operation;

Fig. 7 is a perspective view of the apparatus at another intermediate stage of operation and with all contacting sealing surfaces simultaneously in operation;

Fig. 8 is a developed view of a portion of an improved metallic liner with a portion of the line-embedded metallic foil being shown; and v Fig. 9 is a sectional view on line 9.-9-of Fig. 8 and to a greatly enlarged scale.

In accordance with my invention, I arrange, either manually or automatically, an unsealed metallic liner preform upon a metallic mandrel which is adapted to be 2,898,974 Patented Aug. 11, 1959 ice heated and ,with .themetallicsurface of thatliner in contact with the metallic mandrel. A container to which the liner is to .be sealed issthen disposed in surrounding relation to the liner preform. The container and liner are clamped together against the mandrel, preferably along the side of the liner which is to be sealed to itself, as well as to the container and this clamping pressure 'is maintained until the sealingoperationis completed. The mandrel with the liner and container in place is then moved to successive positions against pressure applying members which seal the liner to the container, except at one .open end. Upon completion of the sealing operation, the mandrel is retracted to a discharge and loading position, at which timethe lined container is removed and a new preform and detached container is subsequently installed on the mandrel.

While the invention in its broader aspects is adapted for heat-sealing non-metallic liners or liners of various metallic materials to containers, I prefer to employ the improved liner comprising an aluminum foil layer laminated with a microcrystalline wax layer to a layer of tissue paper and known by the trademark Reyseal and as disclosed'more fully in the copending application of Raymond E. Jacke, Serial No. 638,016, filed February 4, 1957, andassigned to Reynolds Metals Company. Referring now to Figs. 8 and 9, the liner designated generally at 10-preferably comprises a rectangular shaped, laminated sheet 'having on one side a thin sheet 11 of metallic-foil, preferably aluminum, and on the other side a somewhat thicker sheet 12 of a porous material, such as tissue paper. A centrally located layer 13 of a heat sealing composition, such as a micro-crystalline wax is providcd between sheets 11 and 12. Accordingly, when heat is applied to the liner, the wax tends to flow through the tissue sheet and to become available for bonding to a surface in contact therewith. However, since it is desirable, if-not essential, in some usages of lined containers to have the metallic sheet 11 bonded to itself along side and end seals, I also provide for passage of the wax through the otherwise impervious metallic sheet 11. This preferably is accomplished by lightly puncturing the sheet 11 along peripheral edges, as seen at the bands 14, 15 and 16, as by passing thereover an abrading means, such as a rouletting wheel, or roller covered with emery cloth, or the like, while under sufiicient pressure to form bands of spaced pin-holes of sufficient size to permit the heated wax'to exude therethrough for sealing purposes.

Furthermore, due to the tendency of the thin metallic sheet 11 to be abraded or galled by moving contact with a heated metallic mandrel, wrinkling of the metallic sheet, or wear thereof, .or both, may occur in manufacture of the lined container unless provision is made to overcome the same. As taught by the Jacke invention, these disadvantages may be overcome byline-embedding the metallic sheet into the layer of wax therebeneath. As seen in Figs. 8 and 9, a series of closely spaced parallel small grooves 17 are formed in one direction across the entire outer surface of sheet 11, these grooves being intersected by a similar series of grooves 18 at a suitable intersecting angle'thereto; Asthe respective grooves 17 slipping characteristics .arefound when motion occurs between thatshcet and the surface of a metallic mandrel. Moreover, expansion of themetallic. sheet due to heating can take place without warping or wrinkling of the surface of the sheet as a whole.

With the foregoing in mind, an unsealed liner perform of the described Reyseal material and generally shown at 21 in Figs. 2 and 3, upon being suitably folded by any conventional folding apparatus, is adapted for positioning endwise upon mandrel 22, later to be described. It will be understood that in this folding operation, one end of liner projects axially of the liner preform to form an open end which may slip snugly upon the mandrel, the other end of that liner having band folded upon itself, and the sides of that liner having bands 14 and 16 folded upon themselves in interlocked arrangement as shown by said Jacke application. Thus, as seen in Fig. 2, the tissue lamination of the liner is exteriorly exposed and the metallic side 11 of the liner is in contact with the mandrel.

The side seal of the preform is in general the most important seam to seal, since it must sustain bulging stresses of the filled container and is usually extended over the end portion of the container as seen generally at 24 in Fig. 2. As an important feature of the invention, this side seal is disposed on the side of the mandrel which is to receive a prolonged and uninterrupted pressure.

Following positioning of the unsealed, folded preform upon the mandrel, a conventional container 23, open at one end and sealed at its sides and other end, is positioned over the preform in substantially enveloping relation thereto and with its inner surface in contact with the tissue layer 12 of that preform. This container may be of any suitable material to which the liner will adhere, but I prefer to use a conventional cardboard container.

Reference now is made to Fig. 1 showing one form of apparatus embodying the invention and adapted for efficiently lining the container above mentioned. While the apparatus is shown detached from the means for folding the preform, and for filling the lined container, it will be understood that, if desired, it may be incorporated into known packaging machinery by suitable modification thereof to the end that a compact and high speed assembly for container forming, container lining, container filling, and container sealing may be used.

As shown, one satisfactory form of manually operable, inexpensive and mechanically simple apparatus may include a stationary base plate upon which a pair of guide rods 31 and 32 are mounted for support and guidance of a carriage 33. Adjacent their upper ends, the guide rods are braced by a transverse bar 34 and at a suitable location above the uppermost retracted position of the carriage, a stationary housing 35 for a rotatable stub shaft journalled therein, is securely mounted upon a guide rod.

Extending from the outer end of the stub shaft is an actuating member or lever 36 normally held in fully retracted position as by a torsion spring 37 fixed at one end to an abutment on the stationary housing and at the other end to the movable handle. One or more tension springs 38 fixed at one end to the stationary bar 34 and at the other end to the movable carriage 33, serve to hold the carriage in retracted position where it is available for ready insertion or removal of the liner preform and container with respect to the mandrel.

Projecting from the carriage is a hollow metallic mandrel 22, rigidly atfixed as by bolts or welds (not shown) to the carriage 33 at a central location thereof, and adapted for reciprocable movement in a predetermined path as the carriage moves along the guide rods. A

framework comprising pairs of spaced posts' 40, 41; 42, 43; and 44, 45, is rigidly mounted upon the base plate 30 in surrounding relation to two sides and one end of the path of mandrel movement and with the upper ends of the posts terminating in a plane slightly below the bottom of the fully retracted mandrel. Disposed between posts 40 and 41 is a pressure applying member, preferably a cylindrical, rubber-like roll 46, rotatably -on the mandrel. Moreover, any suitable switching means may be employed to apply and cut off current to the 1 ment of the reciprocable carriage 33.

'the mandrel.

journalled in the posts and having a diameter which is sufiicient to 'cause the surface of the roll to press firmly against an outer side of container 23 as the mandrel is moved past the roll 46. Likewise, a pressure applying member, such as roll 47 mounted between posts 42 and 43 and a pressure applying member, such as a shorter roll 48, mounted between posts 44 and 45, are provided for pressing firmly against another outer side and an end respectively of the container during the mandrel movement.

Located between the respective posts and disposed in the path of movement of the mandrel is a platen 50, preferably of a fiat rubberlike material and resiliently mounted upon compression springs 51 which surround guide rods mounted at one end upon base plate 30 and having limiting stops 52 at the other end to limit the upward movement of the platen. This platen is adapted to press firmly against the lower side of the container when the mandrel is lowered to its bottommost position.

Mounted upon the face of carriage 33 is a master pressure applying plate 60 pivotable about hinge 61 and having a boss 62 on its upper face. Pivotally secured upon the boss 62 and upon a pin 63 located at an intermediate point on handle 36 is a link 64 connecting the handle and the master plate 60. The plate 60 preferably is fiat and has a surface 65 of rubberlike material adapted to press upon the upper side of container 23 when installed upon As will thus be apparent, when handle 36 is in normal retracted position under the influence of spring 37, the master pressure applying plate likewise is in raised position with respect to mandrel 22, and the perform and container may be readily installed upon or removed from the mandrel.

Referring now to Figs. 4 and 5, the mandrel may have any suitable polysided configuration, but as shown herein is of parallepiped shape with an undercut portion 66 adjacent its mounting upon the carriage 33. As a result of this undercut portion, the extended open end of the liner I preform is not pressed into close contact with the heated mandrel, thus permitting the wax layer of the liner to remain unmelted at its extreme open end. Disposed within the metallic mandrel on all sides and at the outer end thereof is a high resistance electrical coil 67 em bedded in a ceramic or other suitable heat resistant electrical insulator 68 and connected to an electrical conductor 69 leading through carriage 33. This conductor .may lead to any suitable circuit forming no part of the present invention and which may apply current to the coil 67 under control of a conventional powerstat which varies voltage to maintain a predetermined surface temperature mandrelat desired times.

At its outer end the hollow mandrel is provided with a plurality of small apertures 70 through which a gaseous medium under pressure may be expelled. Leading into the mandrel through carriage 33 is a hose connection 71 .suitably attached to a pressure source which may be controlled by any suitable valve (not shown) adapted to be actuated at the time the liner is completely sealed within the container in order to strip the container from the retracted mandrel and then to be actuated to close off the .source, until the stripping of the subsequent container is desired. It will be understood that both the conductor 69 and hose 71 are mounted for partaking of the move- The operation of the apparatus will now be noted from a comparison of Figs. 1, 6 and 7. With the mandrel,

. carriage and master pressure plate in the fully retracted position of Fig. 1, the metallic liner preform 21 is positioned endwise upon the mandrel and with its most difiicult to seal side seam, as seen at 24, in position below the mandrel surface due to the undercut 66 of that mandrel. With heat being appliedto mandrel 22, the handle 36 is lowered, whereupon plate 60 isbrought into contact with the upper side of container 23 whiehin turn presses against the side seam 24 of the preform which in turn presses its metallic inner surface 11 against the metallic surface of mandrel 22.- This pressure by master plate 60 is continuously applied during the entire lining operation with the result that not only is the tissue layer of the liner securely bonded to the inner surface of the container, but also the m'eta'l to-met'al seal at seam 24 is securely bonded by virtue-of the extended application of pressure. However, despite this prolonged application of pressure of a metallic foil against a hot metallic surface, no scarring or galling of the lineroccurs when the container is removed due to the above'described lineembedded feature of the liner material.

After lowering the plate 60 into operative contact with the upper side of container 23, further pressure'upon handle 36 through its hinged connection with carriage 33 begins to force that carriage downwardly against-the' action of springs 38. As the carriage moves downwardly, carrying the mandrel therewith, pressure rolls 46 and 47 force the sides of the container into contact with the liner preform and at the same time the pressure roll 48 forces the end of the container into contact with the end of that preform. It will be noted that these rolls provide only a line contact with the sides and end of the container, but that two such phases of contact result, during both the downward movement and during the subsequent upward movement. At the time when rolls 46, 47 and 48 complete their first passage across the surfaces of the container, the continued pressure of handle 36 (Fig. 7) forces the mandrel into contact with the platen 50. Further movement of the mandrel downwardly compresses springs 51, causing the underside of the container to be forced against the liner and that liner, in turn, to be forced against the underside of the hot mandrel. After holding the handle 36 in fully depressed position for the time necessary to bond the liner to the underside of the container, the handle is then lifted upwardly, being assisted by the torsion spring 37 and by the tension springs 38. During its upward movement, the second phase of pressure application by rolls 46, 47 and 48 occurs, the application of pressure by master plate 60 having been continuous throughout the operation.

When the mandrel carriage and handle are returned to the position of Fig. 1, pressure fluid is then released through hose 71 and the lined container is automatically stripped from the mandrel without tearing or marring of the metallic surface of the liner.

It has been found that by employing the described apparatus in conjunction with the Reyseal liner, a superior appearance of lined container is secured. The entire inner surface of the container is substantially smooth, without wrinkles and without torn surfaces. A tight metal-tometal seal along the side and end seams of the container results, which makes the lined container particularly well suited for containing liquids and foodstuffs and for later hermetic sealing following filling of that container.

Having thus described the invention and having shown one form of apparatus embodying the same, it will be apparent that various modifications can be made, without departing from my invention, I therefore, do not wish to be limited to the particular modification as shown and contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for securing a heat-scalable liner in a container comprising, a movable mandrel for receiving a liner preform and a detached container substantially completely surrounding said preform, said preform and container being insertable endwise upon said mandrel and removable endwise therefrom, a pressure plate member for pressing said liner andcontainer together against a first side of said mandrel and for holding the same in contact during the lining operation, a resiliently mounted member for pressing said liner and container together against a second side of said mandrel opposite to said first side thereof, means disposed adjacent the path of travel of said mandrel and adapted to press said liner and container together against the remaining sides and one end of said mandrel during its movement into and from engagement with said resiliently mounted member, means for moving said mandrel, and means for applying heat to said mandrel thereby toseal said liner preform to said container.

2. Apparatus as defined in claim 1 including means normally holding said mandrel in retracted position for ready insertion and removal of said liner preform and container, said mandrel moving means being connected to said pressure plate member for moving said mandrel against the action of said mandrel retracting means.

3. Apparatus for securing a heat-sealable metallic liner in a container comprising, in combination, a movable metallic mandrel for receiving a liner preform and a detached container substantially completely surrounding said preform, said preform comprising a folded laminated sheet having a metallic surface in contact with said metallic mandrel, a bonding surface in contact with said container and an intermediate wax layer between said metallic and bonding surfaces, and with said folded preform having an unsealed seam disposed along a first side of said mandrel, said preform and container being insertable endwise upon said mandrel and removable endwise therefrom, a pressure plate member for pressing said liner and container together against said first side of said mandrel, and for holding the same in contact during the lining operation, a resiliently mounted member for pressing said liner and container together against a second side of said mandrel opposite to said first side thereof, means disposed adjacent the path of travel of said mandrel and adapted to press said liner and container together against the remaining sides and one end of said mandrel during its movement into and from engagement with said resiliently mounted member, means for moving said mandrel and means for applying heat to said mandrel thereby to melt said wax layer and to seal said bonding surface to said container and said seam to itself.

4. Apparatus as defined in claim 3 including a hollow mandrel having a controlled source of pressure fluid connected thereto and apertures in said mandrel end directed against the end of said lined container thereon, whereby said container may be stripped from said mandrel by means of pressure fluid emerging from said apertures.

5. Apparatus for securing a heat-sealable liner in a container comprising a framework having a carriage movably mounted thereon, a mandrel rigidly mounted on said carriage for receiving a liner preform and a detached container substantially completely surrounding said preform, means normally holding said carriage and mandrel in a retracted position, means mounted upon said framework and disposed in the path of travel of said mandrel for pressing said liner and container together against three sides and one end of said mandrel, a pressure plate member for pressing said liner and container together against one side of said mandrel and for forcing said carriage from said retracted position thereby to carry said mandrel into contact with said means disposed in its path of travel, means for moving said pressure plate to cause travel of said movable carriage, means for retracting said pressure plate to a position normally out of contact with said mandrel, and means for applying heat to said mandrel thereby to seal said liner to said container.

6. Apparatus as defined in claim 5 wherein said means mounted upon said framework for pressing said liner and container together against said mandrel includes rotatably mounted rolls disposed adjacent the path of mandrel travel and engageable by the sides and end of said container.

7. Apparatus as defined in claim 5 wherein said means mounted upon said framework for pressing said liner and container together against said mandrel includes a resiliently mounted platen disposed in the path of mandrel travel and engageable by one side of said container.

8. Apparatus for securing a heat-sealable liner in a container comprising a framework having a carriage movably mounted thereon, a mandrel rigidly mounted on said carriage for receiving a liner preform and a detached container substantially completely surrounding said preform, means normally holding said carriage and mandrel in a retracted position, means mounted upon said framework and disposed in the path of travel of said mandrel for pressing said liner and container together against three sides and one end of said mandrel, a pressure plate member hinged at one end to said carriage and adapted to press said liner anl container together against one side of said mandrel, a carriage actuating lever mounted upon said framework and movable against the action of said carriage retracting means, means connecting said actuating lever to said pressure plate member whereby said pressure plate may engage said mandrel during the entire movement of said carriage, and means for applying heat to said mandrel thereby to seal said liner to said container. 7

9. Apparatus as defined in claim 8 including means interposed between said actuating lever and framework for holding said lever and connected pressure plate normally in retracted position.

References Cited in the file of this patent UNITED STATES PATENTS 1,284,706 Kempton Nov. 12, 1918 1,480,143 Bent Jan. 8, 1924 1,585,642 Bello May 25, 1926 1,597,677 Everett Aug. 31, 1926 1,976,259 Jahne Oct. 9, 1934 2,364,406 Vergobbi Dec. 5, 1944 2,417,226 Weyant Mar. 11, 1947 2,446,038 Amigo July 27, 1948 2,555,380 Stuart et a1. June 5, 1951

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