EP0020099A1

EP0020099A1 - Method of forming a can

Info

Publication number: EP0020099A1
Application number: EP80301705A
Authority: EP
Inventors: Paul M. Erlandson; Donald J. Roth; Ihab M. Hekal; John Walter
Original assignee: Continental Group Inc
Current assignee: Continental Group Inc
Priority date: 1979-05-30
Filing date: 1980-05-22
Publication date: 1980-12-10
Also published as: ATE9215T1; DK232380A; CA1130732A; ES491961A0; JPS6211935B2; ES8105593A1; AU537477B2; JPS5632228A; EP0020099B1; AU5884980A; KR830002628A

Abstract

A container which is formed of two cup-shaped members (12, 14), one member (12) being a bottom and the other member (14) being a top. The two members have end walls which are configurated to resist deformation under high internal pressures as may occur in beverage containers. The members have cylindrical bodies (20, 28) and an end portion (34) of one of the bodies (12) is radially inwardly offset so as to be receivable in the other (14) of the members. Prior to assembly, an adhesive (38), preferably in powder form, is applied to the offset end portion (34) and the two halves (12, 14) are joined together by first heating the larger diameter end portion to facilitate assembly, then telescoping the end portions with the inner end portion (34) then being heated so as both tightly to fit within the outer end portion and to fuse the adhesive (38).

Description

This invention relates a container assembly and to a'method of forming same.
It is conventional to make cans and like containers in two pieces with the body and body wall being integrally formed and a separate top closure unit being secured thereto by a seaming operation. The forming of the body and body wall as an integral unit poses a number of problems. First of all, because of the relatively great height as compared to diameter of the body, the drawing or wall ironing operation results in an undue thinning of the metal and prevents proper control of the bottom thickness. Secondly, the metal is severely worked to the extent that flanging of the upper end of the body to facilitate the seaming of the top end unit thereto frequently results in cracking.
The object of the present invention is to provide a container assembly and method of forming same which overcomes these problems.
Accordingly, the present invention provides a container assembly characterized by top and bottom cup-shaped container members, each of said container members having a cylindrical body including a free end portion terminating in a free open end, said end portion of one of said container members being radially offset relative to an adjacent portion of the respective body a distance at least as great as the wall thickness of the body of the other of said members, and an adhesive coating on one of said free end portions.
The present invention also provides a method of forming a container characterized by the steps of forming two cup-shaped container members each including an integrally formed body and end, said container members including a container top and a container bottom and one of said container members including a radially offset end portion, applying a layer of adhesive to said offset end portion, telescoping said end portions, and heating said end portions to fuse the adhesive and sealingly bond together said end portions.
In accordance with this invention, the can body is formed in two pieces. However, instead of one piece including an elongated tubular body and the other piece being a relatively flat end, both members of the container are of generally the same shape and size with each member being of a cup shape. In this manner the diameter of the body approaches the height of the body of each of the members and the members can be readily formed in a conventional wall ironing operation with there being a maximum control over the wall thicknesses. By joining tubular bodies as opposed to securing an end unit to a body by a seaming operation, the customary flanging and folding of the metal is eliminated and the two body portions may be telescoped with respect to one another and bonded together by way of a simple joint or seam. Further, the bottom wall of the bottom member may be readily shaped, such as by doming, etc., so as to withstand the high internal pressures of carbonated beverages and at the same time providing an adequate support for the container. In a like manner, the top wall of the top member may be provided with a suitable filling opening and such dispensing means as may be de- sired.
Preferably, a heat activatable adhesive is applied to the offset area within the offs This can all be accomplished automatically. The two container members are then disposed in alignment and the larger diameter end portion of the two container members is first heated, preferably by means of an induction heating coil, so as to increase the diameter of that end portion for receiving the end portion of the other container member. The two container members are then telescoped, after which the end portions of the telescoped container members are further heated so as both to expand the inner end portion and to fuse the adhesive.
After the two container members have been joined, a suitable label may be applied thereto both for the purpose of identifying the product and masking the joint between the container members. The label is preferably a shrink label which has the end portions thereof extended beyond the container body and engaging both. the top and bottom end walls.
In the drawings:

Figure 1 is an elevational view of a container formed in accordance with this invention.
Figure 2 is a top plan view of the container of Figure 1.
Figure 3 is a bottom plan view of the container of Figure 1.
Figure 4 is an elevational view showing a step in the formation of the container of Figure 1.
Figure 5 is an elevational view similar to Figure 4, and shows the two container members forming the container of Figure 1 as they are assembled.

Referring now to the drawings in detail, it will be seen that there is illustrated in Figures 1-3 a container which, is formed in accordance with this invention, the container being generally identified by the numeral 10. Basically the container 10 is a can and will be so identified hereinafter. However, the principles of this invention will apply to and it is proposed to form cans which may vary in size from those of small capacity such as seven ounces and most particularly twelve and sixteen ounces, to relatively large cans having a capacity as great as five or 6 liters. Accordingly, the use of the word "can" to describe the invention is not intended to be limiting.
The can 10 is of a two-piece construction and includes a bottom member 12 and a top member 14. The members 12 and 14 are joined together as at 16 intermediate the height of the can 10. After the members 12 and 14 are joined, it is preferred that there be disposed around the entire length of the can body a label 18 which is preferably in the form of a shrink wrap, the label 18 will be described in more detail hereinafter.
It is preferred that the. container member 12, as is best shown in Figure 4, have a cylindrical body 20 and an integral bottom wall. The bottom wall is preferably of a bulged configuration including an overall bulging 24 having projecting therefrom in circumferentially spaced relation a plurality of outwardly directed protrusions 26. The bottom wall construction is one which will withstand the high internal pressures of carbonated beverages and even though a certain amount of outward bowing will be effected from the pressure of the product therein, the projections 26 will be so related to the bulge 24 as always to project downwardly therebeyond to form a stable platform for the can.
The container member 14 is also provided with a cylindrical body portion 28 and a top wall 30. The top wall 30 may be bowed or may b.e generally frustoconical, as shown. In order to effect filling of the can, the top wall 30 is provided with a central filling opening 32 which, after filling, will be closed by means of a suitable plug (not shown) preferably in the form of a rivet-like member.
The can 10 may be opened for dispensing the product in various manners depending upon the size of the can and the application thereof. If desired, the plug may be made removable and replaceable so that the filling opening 32 may also be utilized as a dispensing opening. On the other hand, if the can is of a small size, it may be provided with a conventional easy opening feature in the end wall 30 adjacent the filling opening 32.
When formed, the diameters of the bodies 20 and 28 are preferably the same. In order to telescope the end portions of the bodies. 20 and 28, it is necessary that the diameter of the end portion of one of the bodies be changed. In the preferred embodiment of the invention, the container member 12 has an end portion 34 which is radially inwardly offset to define a necked-in end portion joined to the remainder of the body 20 by a shoulder 36. The offsetting of the metal of the end portion 34 is between 1.1 and 2 times the thickness of the metal of the bodies 20, 28.
It is to be understood that the container members 12 and 14 may be formed by way of automatic forming machinery in a conventional manner, and no description of the forming operations is required here. The container members 12 and 14 will be supplied to an assembling machine in two rows. A suitable coating of adhesive 38 is applied to the exterior of the end portion 34 either in the assembling machine or prior thereto in a conventional manner. The adhesive 38 may vary in composition, but must be one which will bond either directly to the metal of the container members or to any coatings applied thereto. Preferably the adhesive is a powder type adhesive which may be applied electrostatically to the end portion 34 and may be fused by heating.
The container members 14 first move through an induction heating coil 40 while the container members 12 remain spaced therefrom but aligned therewith. The induction heating coil 40 may be in the form of two bars which are spaced apart and the container members 14 may roll therebetween to assure uniform circumferential heating of the free end portion of the body 28 in the manner shown in Figure 4.
When the end portion of the body 28 is heated, it will expand and permit freedom of assembly of the container member 12 with the container member 14 by an axial movement of the container member 12 as shown in Figure 5. Thereafter, the assembled container members 12 and 14 continue to move between the two bars of the induction heating coil 40 with the result that the end portion 34 of the container member 12 becomes heated and also expands so as tightly to press the adhesive 38 between the two container bodies 20 and 28. The adhesive is fused by the heat absorbed from the heated end portions of the bodies 20 and 28. The joined together container members 12 and 14 then move out of the area of the induction heating coil 40 and rapidly cool.
The label 18 may then be applied in any conventional manner with the label, as described above, when it is a shrink label, extending beyond the body of the can and overlapping the bottom wall 22 and the top wall 30 so as securely to anchor the label on the can.
Although only a preferred embodiment of the invention has been specifically illustrated and described herein, as well as a preferred method of assembling the container, it is to be understood that minor variations may be made in the container construction and the method of assembling the two halves thereof without departing from the spirit of the invention.

Claims

1. A container assembly characterized by top and bottom cup-shaped container members, each of said container members having a cylindrical body including a free end portion terminating in a free open end, said end portion of one of said container members being radially offset relative to an adjacent portion of the respective body of a distance at least as great as the wall thickness of the body of the other of said members, and an adhesive coating on one of said free end portions.

2. The container assembly of claim 1, characterized by the radially offset portion of said one of said container members being offset a distance at least as great as the wall thickness of the body of the other of said container members.

3. The container assembly of claim 1 or 2, characterized in that said radial offset is an inwardly disposed offset.

4. The container assembly of claim 1, 2 or 3 characterized in that said offset is on said bottom member.

5. The container assembly of any of claims 1 to 4, characterized in that said adhesive is on said one container member and is seated in said offset.

6. The container assembly of any of claims 1 to 5, characterized in that said adhesive is of the heat activated type.

7. The container assembly of any of claims 1 to 6, characterized by a label surrounding said cylindrical bodies and masking the joint therebetween.

8. A method of forming a container characterized by the steps of forming two cup-shaped container members each including an integrally formed body and end, said container members including a container top and a container bottom and one of said container members including a radially offset end portion, applying a layer of adhesive to said offset end portion, telescoping said end portions, and heating said end portions to fuse the adhesive and sealingly bond together said end portions.

9. The method of claim 8, characterized in that said container members are formed of metal and said heating is induction heating.

10. The method of claim 8 or 9, characterized in that the radially outer one of said end portions is first independently heated to increase the internal diameter thereof and then the radially inner one of said end portions is axially inserted into said enlarged outer end portion.

11. The method of claim 10, characterized in that the inner end portion is then heated to expand said inner end portion within said outer end portion.