US2214435A - Method of coating cans and attaching end members thereto - Google Patents

Description

H. ONEIL Sept. 10, 1940.

METHOD OF COATING CANS AND ATTACHING END MEMBERS THERETO Filed 1, 1937 Patented Sept. 10, 1940 v UNITED STATES PATENT OFFICE' METHOD OF COATING CANS AND ATTAOH- ING END MEMBERS THERETO J amcs H. ONeil, Syracuse, N. Y., assignor to Continental Can Company, Inc., New York, N. Y., a corporation of New York Application November- 1, 1937, Serial No. 172,302 2 Claims. (01. 113-120) The invention relates generally to the art of the description, the appended claims, and the sevforming metallic receptacles and has for an' oberal views illustrated in the accompanying drawject to provide a novel method of coating cans ing. and attaching end members thereto in a manner In the drawing:

for assuring against the presentation, of bare Fig. 1 is a detail vertical section illustrating the 5 metal portions to contact with contained prodstep of coating the can.

ucts- Fig. 2 is a detail vertical section illustrating It is customary to interiorly coat metallic conthe step of air dryingthe can. tainers adapted to receive certain products, so Fig. 3 is an enlarged fragmentary section illusthat direct contact between said products and trating the step of seaming an end member in m the metal of the containers is avoided. This'is place while the protective coating is in a tacky particularly true in the canning of beer, since it state.

has been found that the slightest exposure of the Fig. 4 is a fragmentary diagrammatic section tin forming the outer surface of the metal causes illustrating the step of baking the end member a chemical reaction upon the beer sufficient to equipped can to harden the protective coating change its appearance, making it cloudy and unand drive out volatile solvents confined within 15 marketable. The protective coating has been apthe end member securing seam.

plied in various ways, as by dipping, flushing, or In practicing the method, the can bodies 5 are flooding the inside, outside, or both inside and coated interiorly, or both interiorly and exterior-1y, outside'of the can bodies in the coating solution, by any approved method. As a single exemplifiusually lacquer or enamel. An example of apcation of the coating step I have shown, in Fig. 1 paratus capable of coating can bodies by the dipof the drawing, a portion of the Kronquest patent ,ping method is to be found in the application for application apparatus hereinbefore referred to. Letters Patent filed by Alfred L. Kronquest, on The can bodies are supported on individual car- April 12, 1937, Serial Number 136,473 now-Patent riers 6 which are lowered and lifted by suitable Number 2,206,778. After the protective coatings mechanisms to immerse the cans in and remove are applied they are suitablyhardened, as by them from the protective coating bath 1. After bakingthe cans are coated internally and externally by Hardened coatings of the character stated are this immersion they a attached t0 clips 3 somewhat brittle, and when can ends are applied, pending from a conveyor chain 9 and are carried and seamed securely in place, usually by a double along in an air drying chamber. 30 roll seam, portions of the hard. coatings are This air drying step is il s in 2 cracked or ruptured by the rolling of the scam, the drawi g a may be carried on with or Withand as a result, bare metal surfaces are exposed 'out forced circulation and in the presence of to contact with products to be contained in the heat or without it asmaybe desired, the demands 3 cans. v of the invention being satisfied by any form of Seeking to remedy these faults, the invention drying which will suitably bring the can coatings resides in the novel method of coating cans and to a tacky state. attaching end members thereto, which comprises After the coating and the air drying steps the steps of interiorly coating the can bodies, air have been completed an end member ID is im--' 40 drying the coatings to a tacky state, applying end mediately applied to the can' body and seamedmembers, seam-securing said members in place securely in place as indicated at H in Fig. 3 of while the coatings are tacky and including tacky the drawing. While the invention is not limited coated portions in the seams, then baking the to the formation of a double roll seam this form N member equipped cans to harden said coatings of scam is commonly employed for this purpose 45 and drive .out volatile solvents contained in said and is for that reason illustrated herein'as an seams. exemplification of the step of seam-securing an With the above and other objects in view that end member on a tacky, coated can. Any of the will hereinafter appear, the nature of the invenwell known double seaming mechanisms may be tion will be more clearly understood by following employed in performing this step of the method 50' and an example of such mechanisms is to be found in the patent to A. L. Kronquest, issued April 1,1930, as No. 1,752,912. In these mechanisms the double seam is formed by a chuck and successively operable first and second operation and chipping or flaking off and exposing the bare metal is avoided. The plasticity of the coating also aids somewhat in the formation of a perfect seal in the-seam because of its ability to conform readily to the interstices between the seam components.

1 The end members referred to herein are, of course, the can bottom closures, the top end closures being attached after the cans have been filled at the brewery. During the draining off of the surplus protective coating material, as shown inFig. 2, the can body end to which the bottom closure is to be applied is held uppermost. Due to the action of gravity, and the surface tension of the draining coating material, the applied coating film at the extreme upper end of the can body thins out to a considerable extent and, if allowed to harden, would become brittle and. inadequate as hereinbefore stated. The herein described method of attaching the bottom closures to the can body ends while the coatings are tacky overcomes the difiiculties referred to. No such problems are presented at the lowermost or can top closure receiving ends because the coating material drains of! in the direction of these ends, as shown in Fig. 2, and an adequate protective coating always is provided at said ends.

What I claim is: y

1. The method consisting in coating the entire interior surface of a can body with a fluid coating, draining the superfluous fluid coating from the body while one coated end of the latter is uppermost, drying the remaining fluid coating to a tacky condition while said end is uppermost, and seam-securing a closure member coated on its interior face to said end of the body while the tacky condition of the can body coating persists, including the rolling into the seam of part-of said tackily coated end, and thereafter hardening the coating.

2. The method consisting in immersing a can body in a fluid coating, draining the superfluous fluid coating from the body while one end of the latter is uppermost, drying the remaining fluid coating to a tacky condition while said end -is uppermost, double seam-securing a closure member coated on its interior face to said end of the body whfle the tacky condition of the can body coating persists, including the rolling into the seam of part of said. tackily coated end, and. thereafter baking the coating.

JAMES H. ONEIL.

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