US 3072517 A
Abstract available in
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Description (OCR text may contain errors)
Jan. 8, 1963 P. c. GAYLORD 3,072,517
METHOD OF MAKING A COMPOSITE METAL PAPER CONTAINER Filed Sept. 10. 1957 ATTORNEY United States Patent Office Patented Jan. 8, 1963 3,072,517 7 METHOD OF MAKING A COMPOSITE METAL PAPER CGNTAINER Paul C. Gaylord, Staten Island, N.Y., assignor to The Greif Bros. Cooperage Corporation, Delaware, Ohio, a corporation of Delaware Filed Sept. 10, 1957, Ser. No. 683,155 1 Claim. (Cl. 156-83) This invention relates to an improved container or drum and more particularly to an improved container or drum of composite construction made of metal particularly steel and fiber.
Containers made of metal, particularly steel, are commonly used today for storing and shipping fluid and semifluid products such as oil and grease. While steel drums perform satisfactorily for this purpose, the increasing price of steel has created a problem. Many attempts have been made to find substitute materials to be used in containers of this type but containers made of such substitute materials have had recognized disadvantages.
It is accordingly an object of the present invention to provide an improved container or drum of lower cost which will perform satisfactorily in the storing and shipping of fluid and semi-fluid materials.
A further object is the provision of an improved container of the above-indicated type which may be made on equipment presently used in the production of other types of drums and containers thereby minimizing the cost and also the capital investment required for the production thereof.
My invention contemplates the provision of an improved container or drum in the form of a tubular shell of composite construction having an inner shell portion made of metal, particularly steel, and an outer shell portion made of fiber, particularly convolutely wound laminated layers of fiber surrounding and tightly embracing the metallic shell portion.
In the accompanying drawing- FIG. 1 is a perspective view with the outer fiber shell portion partly broken away of a container or drum embodying my invention;
FIG. 2 is a perspective view illustrating one step in the production of my improved container and showing the outer fiber shell portion being 'ensleeved over the inner metallic shell portion;
FIG. 3 is a detailed sectional view through the upper or lower edge portion of the container shown in FIG. 1 and showing one manner in which the end of the shell wall may be beaded or flanged and also showing one method of attaching the head or closure to the shell;
FIG. 4 is a similar detailed perspective view of the upper end of the shell wall of a modified form of container having an open top and with a modified form of bead or flange known as a false wire top;
FIG. 5 is a similar detailed sectional view of the upper end of the shell wall showing a further modified form of beading and removable closure assembly; and
FIG. 6 is a detailed cross-sectional view of the lower end wall of a container showing another modified form of beading and of permanent closure assembly.
My improved container or drum comprises a tubular shell of composite construction indicated generally at 10 and provided with suitable heads or closures cooperable to engage with the two ends thereof. In each ofthe illustrated forms of my invention the composite tubular shell comprises an inner tubular shell portion 11 made of metal, preferably steel, and an outer tubular shell portion 12 made of fiber, preferably convolutely wound laminated layers of kraft paper. The metallic shell 11 may be made in the same manner as the shell of a conventional steel drum from sheet or strip stock formed into a cylindrical tube with the two edges suitably secured together as by welding as indicated at 14. However, I have wound that when making a container or drum in accordance with my improved composite construction I may employ a steel of substantially lighter gauge than that required for conventional steel drums of similar size and design for similar service. As an example, in conventional steel drums for full liquid use of 16 gallons capacity 20 gauge steel is generally required, and I have found that when made in accordance with my present invention I may form the inner tubular shell of metal of 29 gauge or less.
The fiber outer shell portion 12 may be made in the same manner as the fiber shell of a conventional fiber drum by winding kraft paper convolutely around a mandrel suitably laminating the successive layers together by means of an adhesive having a liquid solvent or carrying agent. Generally speaking, however, I require fewer convolutions or laminations than is required in a'conventional fiber drum of similar capacity and I have found that for most purposes between four and ten laminations serve satisfactorily. The fiber outer shell portion is formed around a center or mandrel having substantially the same diameter as the outside diameter of the metalic inner shell portion 11.
I have found that after the liquid solvent or carrying agent of the adhesive employed in laminating the fiber layers together has penetrated into the fibers and prior to the time that the adhesive sets, the fiber shell expands temporarily. During this period while the fiber is still moist prior to the setting of the adhesive and while the shell is in expanded condition, I ensleeve the fiber outer shell portion 12 over the metallic inner shell portion 11 in the manner indicated in FIG. 2. The two shell portions are preferably of appropriate length and should be brought into relative alinement with each other. The two shell portions are then maintained in assembled relationship while the adhesive sets. During the period when the adhesive is thus setting, the fiber outer shell portion contracts to its original mandrel formed size and tightly embraces the metalic inner shell portion forming a tight frictional fit and engagement. In this connection I have found that better results are obtained if a bonding agent is employed between the metallic inner shell portion and the fiber outer shell portion, and, prior to assembling the parts together, a suitable bonding agent or adhesive for metal is applied to the outer surface of the shell portion 11 or the inner surface of the shell portion 12 with the result that when the adhesive has set and the outer shell has shrunken, the two shell portions will be firmly bonded together. The bonding of the two shell portions togther results in greatly increased strength.
When the composite tubular shell has thus been formed the upper and lower edges of the shell wall are preferably suitably finished by beading or fianging and closures or heads are permanently or releasably assembled therewith. The beading or flanging of the edges of the shell wall results in increased strength in those areas which are subjected to stresses and impacts when the containers are dropped or are stacked one on top of the other. This is particularly true when the shell wall is flanged or beaded outwardly so that the metallic inner shell portion is extended over the edge to give additional protection to the fiber outer shell portion and the fiber encased within the head or flange is more firmly molded and compacted to reinforce the heading.
In the form of container shown in FIGS. 1 and 3, I have shown heads or closures 15 permanently secured to both the upper and lower ends of the container by outwardly rolling the flange or head. The closures 15 at the upper and lower ends of the container, as illustrated in FIGS. 1 and 3, are of similar construction with the exception that the closure 15 at the upper end is provided with removable threaded fittings 16 through which the material may be inserted into or removed from the container. The closures or heads are preferably made of steel of heavier gauge than that employed in making the metallic inner shell portion 11. A sealing compound may be coated on a heading disc where it contacts the top area of the inner metal shell to adequately seal the closure air tight and liquid tight. The central portion of each closure 15 is in the form of a disc fitted into the end of the composite shell and the peripheral portion of each closure 15 extends over the end of the shell as indicated at 17 in FIG. 3 and the end of the composite shell wail together with the outer peripheral edge of the closure are rolled outwardly and inwardly into a relatively flat bead 18 extending around the upper and lower outer edges of the container. In this connection, the head or flange is preferably formed while the fiber of the outer shell portion is still moist and before the adhesive has fully set. The rolling of the bead is accomplished under pressure with the result that the fiber core of the bead is molded and compacted forming a hard, bonded, reinforcing core for the bead. As will be seen from FIG. 3, the outer surface of the head is protected by two layers of metal, namely, by the peripheral edge portion of the closure and by the inner shell portion 11 which has been folded outwardly and inwardly in the manner shown and the terminal portion of the periphery of the closure is embedded in the bead.
When the container is made and assembled in the fashion described above and as illustrated in FIGS. 1, 2 and 3, the composite shell forms an integral unit with all parts firmly bonded and secured in place. Instead of using the form of closures shown in FIGS. 1 and 3, any other desired type of permanent or removable closure may be employed. Examples of other types of closures and assemblies are shown in FIGS. 4, 5 and 6. Thus, in FIG. 4 I have illustrated a container having an open upper end with a form of outwardly turned flange or bead known as a false wire top. Thus, it will be seen that the upper end of the composite shell wall has been rolled outwardly into a rounded head 19 with the metallic inner shell portion 11 extending outwardly and around the compacted fiber of the outer shell portion which again forms a reinforcing core for the bead. The bead and the false wire top shown in FIG. 4 is also formed while the fiber is still moist and before the adhesive has fully set and it is formed under pressure so that the fiber is compacted and molded into the desired rounded shape. It will be appreciated that any type of cover assembly may be used with the open ended container shown in FIG. 4.
In FIG. 5 I have illustrated another form in which the upper end of the composite shell wall may be finished to receive a removable closure of the type shown at 20. In this form of container I secure a metal chime strip 21 around the outer surface of the upper end of the shell and arrange it so that it overlaps the top of the shell as shown at 22. The entire composite upper portion of the shell is then formed with an external groove and an internal head 26 and this operation is performed while the fiber is still moist and before the adhesive has fully set. A metallic removable head or closure with a flexible gasket 31 may then be assembled with the upper end of the container in the manner shown and is provided with a portion 23 which rests on the internal bead of the shell and another portion 24- forming a dependent apron which overlaps and extends downwardly around the outer surface of the shell. The closure may be removably held in place by a split clamping rim 25 of conventional construction having an upper flange which overlaps the head and a lower flange which projects into the groove of the shell.
Another modified form of permanent closure assembly is illustrated in FIG. 6. In this form of assembly a metallic chime strip 27 is secured around the outer surface of the lower portion of the composite shell so as to overlap the lower edge thereof and the entire assembly is then provided with an external groove and internal bead near the lower end thereof as shown at 28. The face of a metallic closure head 29 which contacts the inner surface of the inside metal shell may be coated with a bonding material to insure an air tight and liquid tight closure. This operation of grooving and beading is likewise performed while the fiber is still moist and before the adhesive has fully set. A metallic closure 29 is then permanently secured in place by an inturned flange or bead 39. In this connection, the closure 29 consists of a disc portion fitted into the lower end of the shell so as to rest against the internal bead of the shell and with a dependent peripheral apron. The peripheral portion of the closure and the lower end wall of the composite shell and chime strip are then rolled or beaded inwardly as shown at 39 while the fiber is still moist and before the adhesive is fully set. This operation is performed under pressure so that the fiber is molded and compacted in the manner shown forming a reinforcing core fully encased within the metallic chime strip, and the head 29 securely bonded to the inner face of the inside metal shell.
In addition to the several illustrated forms of closure assemblies, it will be appreciated that any other desired type of metallic closure assembly may also be employed. A container of composite construction made in accordance with my invention may be used for storing and shipping fluid and semi-fluid products such as oil, grease and the like. Due to the metallic inner shell portion of the metallic closures the container is fully leakproof. Due to the fiber outer reinforcing shell portion steel of lighter gauge may be employed in making the inner shell portion while at the same time providing a complete container assembly of the required strength and durability. Due to the fact that the fiber outer shell is shrunk over the metallic inner shell and tightly embraces it and is preferably bonded thereto a strong unitary construction which will not separate is obtained. The beaded interengagement of the parts at the upper and lower ends of the shell also provide for additional strength and reinforcement in areas of the container which are subjected to stresses and impacts.
Modifications may be made in the illustrated and described embodiments of my invention without departing from the invention as set forth in the accompanying claim.
A method of making a composite metal-paper container comprising the steps of: providing a preformed tubular shell of relatively thin sheet steel stock; forming a tubular paper shell by convolutely winding layers of fibrous paper around a mandrel of substantially the same diameter as the outside diameter of the steel shell, wetting said layers of fibrous paper with an adhesive which contains a solvent liquid, the liquid penetrating into the fibers of the paper shell and physically expanding said paper shell, enslecving said paper shell while wet with said liquid over the steel shell to tightly frictionally fit thereover with the paper layers in expanded and wet condition, rolling the end of the ensleeved paper and steel shell while the paper shell is still wet with liquid into the form of a flanged head for operative engagement with a container end enclosure; and then shrinking the paper shell about the steel shell by setting and drying the adhesive whereby the steel shell is tightly engaged by the outer paper shell.
References Cited in the file of this patent UNITED STATES PATENTS 2,011,452 Lutz Aug. 13, 1935 2,027,962 Currie Jan. 14, 1936 2,249,392 Moore July 15, 1941 2,262,242 LenOX Nov. 11, 1941 2,350,271 Braloff May 30, 1944 2,428,371 Kinberg Oct. 7, 1947 (Gther references on fetid-wing page) 5 UNITED STATES PATENTS AHearn Nov. 27, 1951 Birkland Dec. 25, 1951 Maier et a1 Dec. 30, 1952 Wigert June 29, 1954 Zeek et a1. Aug. 10, 1954 Avery Nov. 23, 1954 Seymour et a1 Mar. 1, 1955 6 Bergstrom Dec. 20, 1955 Bergstrom Dec. 25, 1956 Bergen et a1 Oct. 22, 1957 Magill et a1. Jan. 7, 1958 FOREIGN PATENTS Great Britain July 19, 1935