GB2194754A - Method of sealing the top portion of a gable-top type container - Google Patents

Abstract

Apparatus for sealing a gable- type top container includes a pair of opposed sealing jaws 1 movable in respective arcuate paths between an outer inoperative position and an operative position in which the jaws 1 are juxtaposed for sealing the apex e of the container. The sealing jaws are each carried by one of a pair of main units 5, 8, Fig. 4 (not shown) the said main units 5, 8 being connected to base units 7 via a pair of link members, the said main units also being pivotably connected together and to a vertically movable lift-lever 10 via a pair of "V" shaped levers 11, 12. <IMAGE>

Description

SPECIFICATION Method of sealing the top portion of a gable-top type container The present invention relates to a method of sealing top portion of a gable-top type container by applying a pair of sealing jaws. A gable-top type container comprises a container having at its upper end a pair of panel members inclined inwardly so that their upper edges are in contact to form an apex and are sealed together at the apex to form a roof-like structure.

According to the present invention there is provided a method of sealing the top portion of a gable-top type container using a pair of sealing jaws movable inwardly simultaneously about respective arcuate paths to an operative position for sealing the apex of the container.

The invention will now be described by way of example only and with reference to the accompanying drawings, in which: Fig. 1 is a lateral view illustrating the movement of the sealing jaws; Figs. 2 and 3 are respectively lateral views illustrating the sealing jaw mechanism activating operations in which Fig. 2 denotes the state before the activating operation and Fig.

3 the state after completing the operation; Fig. 4 is a lateral view illustrating the drive mechanism for activating the mechanism shown in Figs. 2 and 3, Fig. 5 is an enlarged lateral view denoting the upper part of the container before applying the heat-sealing process; Fig. 6 is a perspective view denoting the upper part of the container after implementing the heat-sealing process; Fig. 7 is an enlarged lateral view of the upper part of the container after implementing the heat-sealing process; Fig. 8 is a lateral view of a conventional sealing jaw unit under operation; and Fig. 9 is a plan view denoting the disposition of a conventional guide lever for pressing the aperture of a container.

There are a variety of containers storing liquified food, milk, juice, and the like for sale in the consumer's markets, which are cailed "gable-top" type containers having a roof-like top portion as shown in Figs 6 and 7.

According to conventional practice, liquified food is first charged into container (A) from the aperture in the top portion corresponding to part (A'), i.e, the upper part shown in Fig.

5, after shaping up the bottom of the cylinder square container, followed by folding of a pair of triangular panels (a'), internal-sealing fins (c'), external sealing fins (e'), and inclined roof panels (f'), which are respectively folded at folding lines (a) through (f) as shown in Fig. 6, finally, a pair of superimposed internal sealing fins (c') and (c') and superimposed external sealing fins (e') and (e') are sealed by heattreatment using a pair of sealing jaws (1') and (1') to complete sealing of liquified food into container (A).

The problems underlying the invention are that conventional sealing jaws (1') and (1') are designed so that these jaws are movable linearly. When a pair of sealing jaws (1') and (1') move in this direction, these jaws may rub the external surface of the inclined roof panel (f') to incur damage to the container, thus eventually degrading the commercial value of the printed surface.

Also, there is such a container whose inclined roof panel (f') is provided with spout (B) as shown in Figs. 5 through 8, and thus, when a pair of sealing jaws (1') and (1') moves linearly they may come into contact with spout (B).

It is the usual practice, that when thermally sealing a total of four pieces of internal/external sealing fins (c'), (c'), and (e'), (e') using a pair of sealing jaws (1') and (1') as shown in Fig. 9, guide levers (2) and (2) are employed whose distance is gradually tapered in the direction of their tip portions to allow a cylindrical square container (A') to pass through these guide levers (2) and (2) so that the aperture in the top portion of container is gradually pressed in order of AO, Al, and A2.

However, since the conventional system cannot fully operate a pair of sealing jaws (1) and (1) while causing the guide levers (2) and (2) to continuously press the top portion of the container (A') in order to prevent the sealing jaws (1') and (1') from coming into the contact with these guide levers (2) and (2), the conventional system is obliged to stop the movement of these guide levers (2) and (2) immediately before both of these come into contact with each other. On the other hand, since the container (A') is made of laminated paper material, the top portion being pressed by the force of the laminated material at a position just being out of guide levers (2) and (2) is then opened as shown by the reference numeral A4 after passing through the state A2 shown in Fig. 9. This often causes liquified food to simultaneously splash itself out of the container (A').If the splashed liquified food adheres to the inside of the internallysealed fins (c') and (c') and the externallysealed fins (e') and (e'), the effect of sealing the container will significantly be degraded.

The present invention seeks to overcome the problems outlined above.

In the present embodiment, when operating a pair of sealing jaws in order to seal the top portion of a gable-top type container, both the inclined roof panel (f') and the externally-sealed fin (e') are respectively and gradually folded from the folding lines (f) and (e). When this process is underway, the preferred embodiment of the invention allows the internal bottom edge of the sealing jaw (1) to press against the portion closest to the folding line (e). At the same time, the sealing jaw (1) itself functions as a guide to cause the top portion of the container (A') to be gradually pressed, thus effectively dispensing with guide members.

In the preferred embodiment of the invention, the gable-top type container (A') is con veyed by using a pair of chains (3) shown to the left and to the right of Fig. 2. A pair of sealing jaws (1) and (1) are installed in the positions above the container conveying path (4) so that these jaws can respectively face the left and right directions of Fig. 2. As shown in Fig. 1, the sealing jaws (1) and (1) respectively operate by moving inwardly simultaneously about arcuate paths. To correctly operate a pair of sealing jaws (1) and (1), a link mechanism shown in Figs. 2 and 3 is made available.Of a pair of sealing jaws (1) and (1) shown in Figs. 2 and 3, the upset U shaped main unit (5) having sealing jaws (1) shown to the left is connected to the base members (7) and (7) via a pair of link mem bers (6) and (6) shown to the left and to the right of Figs. 2 and 3. Likewise the other main unit (8) having sealing jaws (1) shown to the right is also connected to the base members (7) and (7) via a pair of links (9) and (9). In addition, of a pair of "V "-shaped levers (11) and (12) having their bottom edges pivotally connected to the vertically movable lift lever (10), the upper edge of lever (11) is pivotally connected to the main unit (5), whereas the upper edge of the other lever (12) is also pivotally connected to the other main unit (8).

When the lift lever (10) shown in Fig. 2 raises its position by a height shown in Fig. 3, the main unit (5) moves itself to the right of the base members (7) and (7) via the lever (11) shown in Fig. 2, whereas the other main unit (8) also moves itself to the left of the base members (7) and (7) via the lever (12) shown in Fig. 2. As a result, the inclined roof panel (f') and the externally-sealed fin (e') of the container (A') on the conveying path (4) are gradually folded from the folding lines (f) and (e), respectively. Next, when a pair of sealing jaws (1) and (1) come into contact with each other as shown in Fig. 3, each two pieces of the internally-sealing fins (c') and (c') and the externally-sealing fins (e') and (e') are laminated together, which are then thermally sealed.

After completing the heat-sealing process, the pair of sealing jaws (1) and (1) respectively return to the initial state shown in Fig. 2. The pair of sealing jaws (1) and (1) are subjected to a specific movement to draw a circular locus as shown in Fig. 1 by operation of link members (6) and (9) while these jaws remain operative. Consequently, when the inclined roof panel (f') and the externally-sealing fins (c') and (c') are gradually folded from folding lines (f) and (e) by the operation of the pair of sealing jaws (1) and (1), the internal bottom edges of sealing jaws (1) and (1) can press a specific portion closest to the folding lines (e).

Viewing this from another aspect, there is no possibility of causing sealing jaws (1) and (1) to rub the external surface of the inclined roof panel (f') of the container (A'). Furthermore, the presence of spout (B) which is installed to the inclined roof panel (f') shown in this preferred embodiment does not obstruct the operation of sealing jaws (1) and {1). Furthermore, the pair of sealing jaws being opposite from each other gradually come closer before eventually coming into contact with each other, they function as guide members to causing the top portion of container (A') to be gradually pressed. This allows the system to dispense with guide members.

In the preferred embodiment the lift lever (10) to moves vertically itself. An example of the lift-lever mechanism is shown in Fig. 4.

The bottom edge of this lift-lever (10) is connected to the upper end of a piston rod (13) of cylinder (14), whereas the bottom end of cylinder (14) is connected to a bell crank (16) which oscillates pivoting a shaft (15). A follower (17) installed to the other end of the bell crank is engaged with the groove of a plate-cam (19) which rotates at a constant speed pivoting a shaft (18). In this mechanism, when the plate-cam (19) rotates itself, in the arrowed direction shown in Fig. 4, pivoting shaft (18) at a constant speed, the engaged position of the follower (17) and the plate-cam (19) varies, thus causing the bell crank (16) to oscillate itself pivoting the shaft (15).

As a result, of the lift-lever (10) being interlinked with the piston rod (13) of the cylinder (14), the lift-lever starts to move in the vertical direction so that a pair of sealing jaws (1) and (1) can eventually be operated in the manner described above. While thermally sealing the top portion of the container, using the pair of sealing jaws, the container is held secure and still by means of the pair of chains (3).

According to the preferred embodiment of the present invention, while thermally sealing the top portion of container (A'), the pair of sealing jaws (1) and (1) operate themselves in the direction of drawing a circular arc. This effectively prevents sealing jaws (1) and (1) from rubbing the external surface of the inclined roof panel (f'), and as a result, there is no possibility of incurring damage to the container to degrade the commercial value of the printed surface. Furthermore, even when spout (B) is set to the inclined roof panel (f'), the presence of this spout (B) does not obstruct the heat-seal operation at all. Furthermore, according to the present invention, while a pair of sealing jaws (1) and (1) internally operate themselves, both of these sealing jaws function as guide members. This eliminates the needs for providing guide levers otherwise needed for gradually squeezing aperture under any conventional sealing system.

Claims (10)

1. A method of sealing the top portion of a gable-top type container using a pair of sealing jaws movable inwardly simultaneously about respective arcuate paths to an operative position for sealing the apex of the container.

2. A method according to Claim 1 in which the sealing jaws act as a guide to press the top portion of the gable-type top container to enable panel members forming the apex to be urged into a position for sealing of the apex to take place.

3. A method according to Claim 1 or 2 in which the pair of sealing jaws are each carried by a respective one of a pair of main units, the said main units being connected to base members via a pair of link members.

4. A method according to Claim 3 in which the pair of main units are pivotably connected together and to a vertically movable lift-lever via a pair of "V" shaped levers.

5. A method according to Claim 3 or 4, in which each of the pair of "V" shaped levers has its bottom edge pivotably connected to a vertically movable lift lever, and each of the said levers has its upper edge pivotably connected to a different main unit.

6. Apparatus for sealing a gable-type topi container including a pair of opposed sealing jaws movable in respective arcuate paths between an outer inoperative position and an operative position in which the jaws are juxtaposed for sealing the apex of the container.

7. Apparatus as claimed in Claim 6 further including a pair of sealing jaws which are each carried by one of a pair of main units, the said main units being connected to base units via a pair of link members, the said main units also being pivotably connected together and to a vertically movable lift-lever via a pair of "V" shaped levers.

8. Apparatus as c!aimed in Claim 7 wherein each of the pair of "V" shaped levers has its bottom edge pivotably connected to a vertically movable lift lever, and each of said levers has its upper edge pivotably connected to a different main unit.

9. Apparatus for sealing a gable-type top container substantially as described herein with reference to and as illustrated in the accompanying drawings.

10. A method of sealing a gable-type top container substantially as described herein.