Composite End Panel for Can or Similar Container

SUMMARY OF THE INVENTION

Use of composite or laminated paper end panels on cans or similar containers has generally proven unstaisfactory due to separation of the end panel from the container sidewall and "wicking " or absorption of liquids at the cutedge of the end panel. Further, forming of the laminate to the desired end panel configuration has heretofore resulted in severe wrinkling and delamination of the composite material.

Accordingly it is the primary object of the present invention to provide an improved laminated paper end panel and method of applying the same to a can or similar container such that the problems of end panel separation, wicking, wrinkling and delaminating are essentially eliminated.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following description, the claims and the several views illustrated in the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of the end panel blank prior to forming.

FIG. 2 is a fragmentary cross-sectional view illustrating the blank being formed.

FIG. 3 is a fragmentary cross-sectional view illustrating the preformed blank being attached to a can body.

FIG. 4 is a fragmentary cross-sectional view illustrating heat sealing of the plastic band to the body.

FIG. 5 is a fragmentary cross-sectional view illustrating the placement of the internal sealant fillet.

As shown in FIG. 1, there is provided a planar end panel blank 1, comprising a circular central panel portion 1a and a peripheral gusset portion 1b for increased flexibility.

As shown in FIG. 2, the gusset portion 1b of the end panel blank 1 is formed with an annular channel 2 having a substantially vertical inner sidewall 2a and an upwardly and outwardly sloping outer sidewall 2b. The channel formation is accomplished through the use of a die 3 and split punch 4. The die has a substantially horizontal planar central face 3a, corresponding in size to the central panel portion 1a of the end panel, and an annular recessed channel face 3b configured to receive the gusset portion 1b of the blank 1. The punch 4 includes a central segment 4a, having a substantially horizontal planar face 5, and an outer annular channel portion 4b configured to mate with the channel 3b of the die 3.

During the channel formation operation, the end panel blank 1 is clampingly held between the central face 3a of the die 3 and the horizontal face 5 of the punch 4. The outer portion 4b of the punch 4 is then displaced toward the die 3 to form the gusset portion 1b to the desired contour.

After the blank 1 has been formed, the inner or upper surface of the channel 2 is coated with a suitable adhesive. The preformed end panel 6 is now joined to the can body or sidewall 7. As illustrated in FIG. 3, an end of the body 7 is placed over the preformed blank 6 with the inner surface of the body 7 in close contact with the inner sidewall 2a of the channel 2.

Final assembly of the end panel to the body 7 is accomplished on a split forming tool 8 comprising a central portion 8aand an outer portion 8b. The central portion 8a includes a substantially horizontal planar face 9, sized to receive the partially assembled container thereon.

An annular recess 10a is formed in the sidewall 10 of the outer portion 8b of the tool 8, near the upper end thereof and the section of the sidewall 10 between the recess 10a and the upper end of the outer portion 8b is recessed sufficiently to permit passage of the completed end panel/body seam as will be more clearly understood by reference to the mode of operation of the tool 8. A plurality of passages 11 are formed in the outer portion 8b and communicate with the recess 10a.

In the final assembly operation, a heat-shrinkable band or hoop 12, formed of a suitable plastic material, is placed within the recess 10a in the outer portion 8b and the partially assembled container is placed on the central portion 8a of the tool 8 with the central panel portion 1a of the end panel resting on the horizontal face 9. The outer portion 8b of the tool 8 is then advanced upwardly, forcing the protruding channel sidewall 2a upwardly and inwardly to a position abutting the outer surface of the body 7. The movement of the tool 8 also beings the band 12 into position overlying the sidewall 2a and overlapping the upper edge thereof. When the band 12 is in position, hot air is introduced into the recess 10a through the passages 11, causing the band 12 to shrink against the end panel channel sidewall 2a and the container body 7 thereby securing the end panel in position and sealing the upper edge thereof.

After the container is removed from the forming tool 8, the band 12 is heat sealed to the outer surfaces of the body 7 and the outer sidewall 2b, by a heat seal die 13, thereby providing a moisture proof barrier. An inner fillet 14 of sealant may be applied to the interior of the container at the juncture of the body 7 and the end panel to further insure the integrity of the joint.

While the preferred method of application and arrangement of parts and tooling has been shown in illustrating the invention, it is to be clearly understood that various changes in details and arrangement of parts or tooling may be made without departing from the scope and spirit of the claims appended hereto.