US3859113A

US3859113A - Method and apparatus for applying compound and post end repair coating to can ends

Info

Publication number: US3859113A
Authority: US
Inventors: Richard A Horvath; William C Stumphauzer; Edwin F Hogstrom
Original assignee: Nordson Corp
Current assignee: Nordson Corp
Priority date: 1972-04-21
Filing date: 1972-04-21
Publication date: 1975-01-07
Anticipated expiration: 1992-01-07
Also published as: CA1003709A

Abstract

A method and apparatus for applying both a layer of resilient sealing compound to the curls of ends of cans and a thin layer of end repair coating over the inside bottom surface of can ends before the ends are assembled onto the body. The compound is applied by forcing it as a very heavy viscous liquid under high pressure through an extrusion nozzle under conditions which result in a coating of compound being evenly applied to a peripheral groove of the rotating can ends while simultaneously the end repair coating is sprayed onto the inside bottom surface. In the preferred embodiment both the compound and the end repair material are applied to the can end while it is rotated in a vertical plane about a horizontal axis.

Description

United States Patent 1191 11 1 3,859,113 Horvath et al. [45] J 7, 1975 [5 METHOD AND APPARATUS FOR 3,015,303 1/1962 Stohlquist 118/318 APPLYING O O AND POST END 3,164,486 1/1965 Pezzuto et al. 117/43 3,322,095 5/1967 Gelbjerg-Hansen et al. 118/55 X REPAIR COATING To CAN ENDS 3,576,659 4/1971 Oliveri et al. ll7/37 R [751 Inventors: Richard A. Horvath, Amherst; 3,584,571 6/1971 Schmoll 117/37 R X FOREIGN PATENTS OR APPLlCATlONS all f Ohio 951,632 3/1964 Great Britain 117/1054 [73] Ass1gnee: lggli'gson Corporation, Amherst, Primary Examiner Ralph Husack Assistant Examiner-Shrive P. Beck [22] Filed: Apr. 21, 1972 Attorney, Agent, or Firm-Wood, Herron & Evans [21] Appl. No.: 246,392

[57] ABSTRACT [52] US. Cl 117/43, 117/96, ll7/l05.3, A method and apparatus for applying both a layer of 118/315, 1 18/316, 1 18/643, 117/2 R resilient sealing compound to the curls of ends of cans [51] Iiit. Cl B44d l/092, B44d 1/10, B44d 1/12 and a thin layer of end repair coating over the inside [58] Field of Search 1 17/37, 105.3, 96, 43, bottom surface of can ends before the ends are assem- 117/2; 118/52, 315, 319, 318, 320, 55, 66, bled onto the body. The compound is applied by forc- 642, 643; 1 13/80 B; 220/64, 67 ing it as a very heavy viscous liquid under high pressure through an extrusion nozzle under conditions [56] References Cited which result in a coating of compound being evenly UNITED STATES PATENTS applied to a peripheral groove of the rotating can ends I 013 858 M912 Bucklin 8/320 x while simultaneously the end repair coating is sprayed 2'l89783 2H9) Eberhar't' 8/319 onto the inside bottom surface. In the preferred em- 213131750 3/1943 Hothersal lxz: 21:11:11] 17/43 x bdimem both the compound and the end repair 2,329,114 9/1943 Fischer 118/319 terial are applied to the can end While it is rotated in 21 2,412,138 12/1946 Fink 118/66 vertical plane about a horizontal axis. 3,008,187 ll/l961 Slade 264/209 3,015,302 l/1962 Miller et al. 118/318 16 Claims, 9 Drawing Figures PATENTED JAN 7 I 75 SHEEI 1 OF 2 PATENTEUJAN 3.859.113 SBEET 20F 2 l METHOD AND APPARATUS FOR APPLYING COMPOUND AND POST END REPAIR COATING TO CAN ENDS This invention relates to the manufacture of metal cans and more particularly to the application of sealing compound and of protective coating to the interior surface of the ends before the ends are crimped onto can bodies during assembly.

Metal cans are made by either drawing a cup from a cylindrical slug of metal, and then attaching a single end to the drawn cup, or forming a cylindrical can body from a sheet of metal and then attaching two ends to the opposite ends of the body. The invention of this application concerns the manufacture of the ends and is applicable to cans made by both processes.

After the can ends are completely configurated but before the end or ends are assembled onto the body, a peripheral groove of the can end is filled with compound,- generally a resilient latex or rubber-like material. When the lid is subsequently crimped onto the can body, this compound forms a fluid and air tight seal in the joint between the can end and the can body.

In the case of can ends which have pull tab type openers, common practice is to score the end and apply the pull tabs to the ends before the ends are assembled onto the can bodies. After the scoring and attachment of thepull tabs, some impervious protective coating must be applied to the inside surface of the end to cover or repair score marks so as to avoid subsequent contact of the can contents with the metal of the can. The practice today is after scoring ofthe end and application of the tab, to spray the inside bottom surface of the end with a lacquer or epoxy type spray so as to completely cover the rivot or score line with an impervious protective coating.

In the past it has been necessary to use two separate applications and curing cycles to apply compound and post end repair spray to the can ends. The necessity for the separation of the two operations was twofold; the application equipment for the compound and repair coating differed and were incompatible and the two materials had differing curing times and temperatures.

At the present time there are three different types of compounds commonly used to seal can ends onto can bodies. One type is thermoplastic hot melt compound which is generally applied at 350 F. Another type is a water base latex gasket material which is applied at ambient or room temperature, generally on the order of 77 F. The third type is an organic solvent compound which may be applied from room temperature to 140 F. but which is generally applied at approximately 1 F. All of these different types of compounds are commonly applied by an extrusion process.

The most common present commercial practice is to supply the compound material to an extrusion nozzle within which there is located a reciprocating plunger. On the upstroke of the plunger, a charge or slug of compound is injected into a nozzle extrusion chamber at approximately 60 pounds per square inch. On the downstroke of the plunger, this charge or slug of compound is forced out of the extrusion nozzle onto a horizontally located can end which is rotating about a vertical axis. In general, the practice is to mechanically actuate the reciprocating plunger by meansof a holddown pad located on the top of the end which moves vertically to effect clampingof the end into a rotating chuck at the compound application station.

This plunger type of extrusion process has been in use for sometime but is subject to numerous criticisms; namely, that there is excessive nozzle breakage which results from impact of the plunger with the nozzle, poor cut off of flow from the nozzle orifice with resulting stringing and drooling of material onto the end, unevenness of application of compound to the end, and excessive bubbling and blistering of the compound.

Most of these objections to the conventional plunger type compound extruding process have been overcome by a high pressure, small nozzle orifice extrusion process which is the subject of copending patent application Ser. No. 90,677, filed Nov. 18, 1970, which application is assigned to the assignee of this application. We have found, though, that the process disclosed in that application does not solve all of the production problems encountered in compound applications. Specifically, we have found that stringing or drooling of the compound from the end after cut off or closing of the valve is less of a problem than with the plunger type applicator but it is still present and sometimes objectionable. We have also found that unless the compound is very precisely mixed and the application temperature closely controlled, the viscosity and rheological properties of the material may prevent it from flowing radially outwardly under the lip of the can curl.

It has therefore been one objective of this invention to eliminate the stringing or drooling of compound onto the end.

Still another objective of this invention has been to minimize the criticality of compound viscosity, rheologicality, and temperature in order for the compound to be properly applied and spread by centrifugal force up under the lip of a can end.

We have found and one aspect of this invention is predicated upon the determination that both of these objectives may be satisfied if the compound is ejected by a high pressure compound application system onto the curl of a can end while the end is located in a vertical plane and is rotated about a horizontal axis. This orientation of the end does not eliminate the stringing or drooling of the material from the nozzle but it does eliminate the detrimental effects of the drool or stringing on the surface of the end. It also reduces the criticality of the compound material properties because the compound is easier to spin outwardly under the lip of the end curl in this vertical orientation than in a horizontal orientation.

Another common production problem encountered in the manufacture of can ends is that of excessive handling equipment, time, and cost because of the numerous operational steps required to complete a can end and prepare it for assembly to a can body. It has therefore been another objective of this invention to eliminate one can end production step and thereby reduce handling and production costs. To that end, another aspect of this invention is predicated upon the determination of a method and apparatus for combining the steps of applying compound and post end repair coating of can ends.

Present practice is to extrude compound onto a can end, cure that compound, usually by air drying it for a period of 36 hours, and then post coating the end with a lacquer, epoxy or other appropriate material, and

oven curing the post coating at a temperature on the order of 350 F.

Heretofore it was generally considered impractical to combine compound application and post end repair coating because the application equipment for the two dissimilar materials were generally incompatible and the curing times and temperatures of the two materials were incompatible. Insofar as the incompatibility of the application equipment was concerned, the compound application equipment generally lacked the degree of adjustment and variability required to combine it with post end repair spray, and additionally, the reciprocating plunger type of equipment often covered the inside bottom surface of the end with a plunger actuating hold-down pad so that that surface could not be sprayed and repaired in the same machine. Insofar as the incompatibility of curing cycles of the two different materials was concerned, the compound was generally found to lose its resiliency and sealing properties if cured simultaneously with the post repair coating material.

These incompatible aspects of the two coating processes have been overcome by the invention of this application. Specifically, we have found that a high pressure, extrusion application of compound to can ends through a small orifice nozzle may be combined with simultaneous airless spray application of a post end repair coating on a single can handling machine and that the two dissimilar curing cycles may be combined by utilizing a two-zone temperature gradient in the oven. The first zone is set for, as an example, 130 F., for three minutes to cure the compound, and the second zone is set for, as an example, 5 minutes at 350 F., or whatever temperature is recommended by the formulator of the post coating material to effect curing of that material. The second high temperature zone has no adverseeffect upon the previously cured compound so long as the compound is completely cured prior to entry into the high temperature second zone. However, if the-compound is not completely cured in the lower temperature first zone, the compound blisters, craters, andloses its sealing property in the high temperature second zone.

The simultaneous application of compound and post repair coating at a single station of an end repair machine is very advantageous because it eliminates nearly one half of the application equipment as well as the need to store and handle ends between compound and post end repair coating applications.

These and other objects and advantages of this invention will be more readily apparent from the following description of the drawings in which:

FIG. 1 is a diagrammatic illustration of a process for simultaneously applying compound and end repair coating to can ends and subsequently curing those materials;

FIG. 2 is a perspective view of a compound and end repair spray station of an end repair machine incorporating the invention of this application;

FIG. 3 is a side elevational view showing the relative FIG. 5A is an exploded cross sectional view through the circled portion of FIG. 5;

FIG. 5B is a view similar to FIG. 5A but after the end has been rotated to spin the compound radially over the can end curl surface;

FIG. 6 is a cross sectional view of a can body and can end after application of the can end to the can body but before crimping the two together; and

FIG. 7 is a view similar to FIG. 6 but illustrating the end and body crimped together.

Referring first to FIG. 1, there is diagrammatically illustrated a compound and post end repair coating system for applying compound and end repair coating to can ends. This system includes an indexible turret 10 upon which there are mounted four individually rotatable heads 11 which rotate at a speed of approximately 2,000 r.p.m. when the heads 11 are located at an application station 12. At this station, compound is extruded from a nozzle 13 into the peripheral groove or curl of a can end and post end repair coating is sprayed from a nozzle 14 as the end rotates through approximately three full revolutions. This requires approximately 90 milliseconds when the end is rotating at 2,000 rpm. The individual heads 11 on the indexing turret 10 are mounted on shafts 15 supported for rotation on the tur- -ret. The heads 11 are rotated by a motor driven drive wheel 16 located at the application station. This wheel 16 has a rubber frictional drive ring 17 on its peripheralthe application station l2. Ends are ejected from the orientation of the end to the compound and end repair the compound application gun of FIG. 4;

head after the turret moves the end away from the application station 12 and over a conveyor 7 where the vacuum of the head is connected to atmospheric pressure. The end thus drops onto the conveyer and is moved through a curing oven 8, as is explained more fully hereinafter. The mechanism for feeding lids or ends onto and off the indexible turret head 10, the lid vacuum hold-down and theejection mechanism have not been illustrated in detail since they form no part of the invention of this application.

It is important to note that the can ends are located in a vertical plane and are rotated about a horizontal axis at the application station 12. Heretofore, the practice in the can manufacturing industry has been to orient can ends in a horizontal plane and rotate them about a vertical axis during compound and end repair coating application. This. vertical orientation has been found to be particularly advantageous in the case of compound application, as is explained more fully herev inafter.

A typical can end of the type with which'this invention is concerned is illustrated in FIGS.- 5, 6, and 7. In

section 20 around the periphery of which there is a p groove or rim 21 and a flange or curl 22 which terminates in a hook 23. The flange 22 overlies the flared end 19 of the can body when the lid is assembled onto the body. When the flange 22 and the flared rim 19 are subsequently crimped together, as depicted in FIG. 7, the two together form the chime 24 of the assembled can.

Referring now to FIGS. 5, 5A and 58, there is illustrated an exploded view of the can end rim 21 and the can end flange or curl 22. In this view, the end is inverted, or turned upside down, from the position depicted in FIGS. 6 and 7. The compound is applied as a very viscous liquid which, when itsubsequently hardens orconverts to the solid state, forms a seal for the can chime between the can end 5 and the body 18. Generally, this compound is a rubber or latex based material. It may be a thermoplastic hot melt material or a water base latex or an organic solvent compound. All three types of compound are commonly and commercially available and are in commercial can use today. In order to apply the compound to the interior surface of the flange or curl 22 of a can end or lid, the compound is extruded from the nozzle 13 of a spray gun 26. In the practice of a preferred embodiment of this invention, this gun 26 is a pneumatically operated spray gun in which the pneumatic pressure functions under the control of a solenoid valve 27 (FIG. 2) to open and close a check valve 28 of the gun. Liquid pressure alone, generally at a pressure in excess of 250 pounds per square inch, forces the compound in a liquid state through the gun and causes it to emerge as a high pressure extruded stream of liquid directed into the peripheral curl 22 of a can end.

Water base latex compounds are generally applied at ambient or room temperature. Thermoplastic hot melt compounds, as well as organic solvent compounds, are heated to either melt or lower the viscosity of the material prior to application. This is generally accomplished by heating the compound in a reservoir 29 to the application temperature. The melted or heated compound is then pumped via a pump '30 through a heated hose 31 into the spray gun 26. If the material is heated, the gun employed is generally of a heated or so-called circulating flow type which has a return line 32 through which compound is returned to the reservoir 29. If, on the other hand,'compound is applied at ambient or room temperature and setting is not a problem, the return line 32 may be omitted. The return line 32 is employed in the circulating flow type of gun to provide a continuous flow of heated compound through the gun so that the compound cannot settle or solidify or harden in the gun when the line is temporarily shut down. The gun per se forms no part of the invention of this application and therefore has not been described in detail. A complete description may be found in an application of E. F. Hogstrom Ser. No. 56,304 which was filed in the Patent Office on July 20, 1970, and is entitled Method and Apparatus for Striping Inside Seams of Cans. That application is assigned to the assignee of this application.

Air pressurefrom a source 36 is supplied via a pneumatic line 37 under the control of a solenoid valve 27 to control opening and closing of the check valve 28 interiorly ofthe gun 26. The solenoid 27A of the valve is controlled by a conventional electric control and timer circuit. In one preferred embodiment it is operable to open the check valve 28 for slightly more than one full revolution of an end on the rotatable head 11 ofthe table 10. If the end is rotating at 2,000 rpm, the timer control circuit is operable to open the check valve within the gun 26 for approximately 30 milliseconds to apply a charge of compound to an end.

The nozzle 13 includes a nozzle tip 40 which is secured to the outer end of a nozzle adapter 41. The purpose of this adapter 41 is to enable the nozzle orifice to be placed in close proximity to the curl 22 of the can end for application of the compound to the end. It comprises a tubular extension 42, a valve seat 43, and a threaded nut 44 for securing the nozzle tip 40 onto the outer end of the adapter. The nut has an inwardly turned flange or lip engageable with a radial flange 45 of the nozzle tip 40 for securing the tip onto the adapter when the nut is threaded onto the outer end of the tube 42. Internally of the adapter there is an extension 46 of the gun plunger. This extension enables the valve 28 of the gun to be located in proximity to the nozzle so as to minimize drool or tailing of compound material after closing of the valve 28 by engagement with the valve seat 43. g I

A hole or axial bore 47 extends from the gun 26 through the nozzle adapter 41, the valve seat 43, and a nozzle insert 49. The insert 49 has an axial bore or aperture 50 which extends the length of the insert. At its forward end this axial bore terminates inthe nozzle orifice 51. It is through this orifice 51 that the compound material is extruded into the curl 22 of the can end. In one preferred embodiment, this nozzle orifice 51 is 0.012 inch in diameter and 0.075 inch in length. An orifice so dimensioned has been found to be appropriate for extruding compound onto ends of beer and beverage size cans which are 2 11/16 inches in diameter.

As may be seen in FIGS. 4 and 5, the compound material indicated at 52 extruded from the nozzle orifice 51 is aimed into the curl 22. Specifically, as indicated, the nozzle orifice 51 is located a distance D from the end curl 22. For standard 2 1 1/16 inch beer cans, the distance. D is adjustable between one-fourth inch and five-eighth inch, depending upon the compound applied through the gun. The orifice 51 also defines an angle of approximately 10 to the axis of rotation of the can end 5 in a diametral plane of the can.

Referring to FIG. 5A, it will be seen that the high velocity stream of compound 52 which results from the high pressure forcing it through the nozzle orifice, usually in excess of 250 pounds per square inch gauge, causes the material to splay outwardly upon contacting the curl 22 of the can end. Specifically, this splay generally causes the material to spread in width to as much as several times the original diameter of the nozzle orifice and the extrudedstream 52 of compound emerging from the orifice. The degree of splay depends upon the material and its viscosity. After application, centrifigal force from the continued high speed rotation of the can end causes the compound to be forced radially outwardly so that it ultimately partially climbs the hooked side wall 23 of the curl 22. As shown in FIG. 5B, the compound 52 ultimately spreads over the complete bottom of the curl 22 and partially over the hooked side wall 23 as a result of the combined effects of the splay, gravity and of centrifugal force. When it subsequently hardens, the compound covers the complete curl 22 including the bottom and most of the hooked side wall 23. It is deliberately kept off the side wall 53 so that it can in no event end upon the inside ofthe can when the end is subsequently assembled onto a can body.

The following chart illustrates differing conditions under which three different compound materials have been applied to can ends according to the practice of this invention:

8. and the post end lip coating gun 55 then turned on for the following 30 milliseconds to apply end repair coating spray 65 during the following or third revolution 01 the end. In this preferred timing cycle, the can end rotates through three full rotations during the first one of which compound is applied and then spun outwardly TEST NO. 1 TEST NO. 2 TEST NO. 3

Material Borden Co. Borden HM-955 Dewey & Almy/W. R. Grace Dewey & Almy Co. Form; No. W05-C097-3 Compound No. 1101 Application Temp. 350 F. Ambient 110 F. Ambient viscosity] Solid/3300 720 cps/720 cps. 1250 cps/560 cps. viscosity at temp. centipoise I Wt./end 215-223 mg. 67-81 mg. 7293 mg. Ends/min. 300 125 300 Rev./end 2.02 2.08 2.02 End rpm 1400 rpm 1300 rpm 1400 rpm Extrusion time/end 86.8 m. sec. 96 in. sec. 86.8 in. sec. Nozzle orifice .020" X .075 .012" X .075" .012" X .075" Pressure 500 psi g. 475 psi g. 800 psi g. Type Material Thermoplastic hot Water base latex Organic solvent melt material material compound material Size can 4 diameter 2 11/16" diameter 2 11/16" diameter The other gun 55 located at the application station 12 is operable to spray post end repair coating onto the complete inside bottom planar surface and the rim 21 Ma can end. In general, this end repair coating is a lacquer or epoxy type of spray which is applied as a very thin film over the complete inside surface 20 of the end and over the rim 21. Prior to the application of the end repair coating, the bottom of the can has a film coating of lacquer or other protective material over the bottom surface but this coating is broken during the application ofa pull tab rivot 56 to the end as well as during the scoring, as at 57, 57, of the end to define the pull tab 58. To repair and cover the rivot 56 as well as the score mark 57, the end repair coating is applied as a last step in the end'manufacturing process to insure that there areno imperfections or breaks in the protective coating over the complete inside surface 59 of the end.

The nozzle 14 as well as the gun 55 are both commercially'available equipment for applying airless sprays to can ends. The gun 55'is pneumatically actuated under the control of a solenoid valve 61 which when opened causes the valve (not shown) internally of the gun to open fluid communication between a lacquer or coating material spray line 62 and the orifice 63 (FIG. 4) of the nozzle 14. Lacquer or spray coating material is then ejected as an atomized spray in a fan shaped pattern onto the can end.

As may be seen most clearly in F IG. 3, the nozzle axis is aimed at an angle of approximately 35 to the surface of the canend and applies a generally elliptically shaped pattern of atomized spray to the end from a, point approximately halfway up the side wall 53 of the end to a point 64 on the opposite side of the center line of the end from the gun. A single rotation of the end while the spray is being ejected from the nozzle orifice 63 results in the application of a film coating over the complete inside surface of the end. g

In one preferred embodiment the spray and

extrusion control guns

55 and 26 are'both similar pneumatically. controlled guns actuated by

identical solenoid valves

61 and 27 and timed through a single conventional commercially available electronic timer. The timer of the two guns 26 and 55is such that the compound gun is first turned on for 30 milliseconds (one revolution of the end at 2,000 r.p.m.), both guns are turned off for the next 30 milliseconds (one revolution ofthe end) and under the hook 23 of the end during the next two revolutions. During the second revolution neither compound nor end coating spray is applied to the end and then during the third revolution the lacquer or post en repair coating from thegun 55 is'applied.

In a second preferred embodiment in which a heavier lacquer coating is required, the can end is on station at the application station 12 for the samethree revolutions of the end but the compound is applied during the first revolution and the lacquer applied during the second and third revolutions. The timing cycle, though, may be varied from one end to another very simply by simply changing the timing of the solenoid valves at the electrical timer (not shown).

After the application of both compound 52 and end repair coating 65 to the end at the-station 12, the turret 10 is indexed to locate the end over the conveyer 7. At that index station 9 the vacuum hold-down of the end is connectedto atmosphere so that the end drops onto the conveyor7 and is transported into the curing oven 8. This oven has two curing temperature zones. In the first zone 8A, the temperature is maintained at approximately F. for the time period required to completely cure the compound on the end 3 minutes in one preferred embodiment. Subsequently the end moves into a second zone 88 where the temperature is maintained at'350 F. for the time period required to cure the end repair coating, approximately 5 minutes in one embodiment. This curing cycle has been found to result in the complete curing of the compound before the curing of the lacquer. If the compound is placed in the high temperature zone 8B or is allowed to enter that zone before it is completely cured, blistering or bubbling of the compound occurs and it loses its resiliency and sealing properties.

The method and apparatus described hereinabove for applying both compound and end repair coating materials to a can end at a single station has numerous ing temperature post end repair coating. The application of the compound through a high pressure pneumatically actuated extrusion gun enables the compound application to be controlled by an electrical timer and thereby imparts a high degree of adjustability and repeatability to the cycle. Additionally, the orientation of the ends in the vertical plane during the application of the compound and end repair coating has been found to materially reduce the problem of controlling tailings or drooling from the nozzle onto the ends. Additionally, this orientation has been found to increase the ease with which compound may be spun upwardly under the lip of the curl after it is applied to the bottom of the curl by the extrusion gun. By enabling the compound material tobe more easily spun up under the lip, the criticality of the compound viscosity and rheological properties has been substantially reduced with the result that there are fewer failures or rejects because of failure to coat that area of the can end.

These and other advantages of this invention as well as modifications which may be made without departure from the spirit of our invention will be readily apparent to persons skilled in the can end coating arts. Therefore, we do not intend to be limited except by the scope of the following appended claims.

Having described our invention, we claim:

1. The method of applying two dissimilar materials to separate areas of a can end, which materials have differing curing temperatures, which method comprises rotating a can end relative to two stationary nozzles located at a single spray station,

ejecting one of said materials as a liquid spray from one of said nozzles onto the bottom surface of said can end while said can end is rotating at said station, ejecting the other of said materials from the other of said nozzles into the curl of said can end while said can end is rotating at said station, and

sequentially exposing both of said materials on said can end to a first low temperature source of heat to cure one of said materials, and then sbsequently exposing said materials on said can end to a second higher temperature source of heat to cure the other of said materials.

2. The method of claim 1 in which said can end is rotated about a horizontal axis at said spray station while said materials are ejected onto said rotating end.

3. The method of applying can end repair coating material and sealing compound material to separate areas of a can end, which materials have differing curing temperatures, which method comprises rotating a can end relative to two stationary nozzles located at a single spray station,

ejecting said can end repair coating material as a liquid atomized spray from one of said nozzles onto the bottom surface of said can end while said can end is rotating at said station,

extruding said sealing compound material from the other of said nozzles into the curl of said can end while said can end is rotating at said station, and sequentially exposing both of said materials on said end to a first low temperature source of heat to cure said sealing compound material, and then sub- 4. The method of claim 3 in which said can end is rotated about a horizontal axis at said spray station while said materials are applied onto said rotating end.

5. The method of claim 4 in which said sealing compound is extruded from the other of said nozzles at a pressure of at least 250 psi. and through a nozzle orifice of less than 0.025-inch diameter.

6. The method of applying two dissimilar materials to separate areas of a can end, which materials have differing curing temperatures, which method comprises rotating a can end relative to two stationary nozzles located at a single spray station,

ejecting one of said materials as a liquid atomized spray from one of said nozzles onto the bottom surface of said can end while said can end is rotating at said station, and

' extruding the other of said materials from the other of said nozzles into the curl of said can end while said can end is continuing to rotate at said station.

7. The method of claim 6 in which said end is rotated about a horizontal axis at said spray station while said materials are ejected onto said rotating end.

8. The method of applying sealing compound material as a thin film in the curl and beneath the curl lip of a can end, which method comprises rotating the can end at high speed about a horizontal axis relative to an extrusion nozzle,

extruding said material in a generally horizontal direction at a pressure of between approximately 25 0 psi. and 800 psi. from said nozzle into the curl of said can end while said can end is rotating about said horizontal axis at said station so that material splay, gravity and centrifugal force all act to move said compound beneath a lip of said curl.

9. The method of claim 8 in which said material is extruded from a nozzle orifice of less than 0.025-inch diameter.

10. Apparatus for applying two dissimilar materials to separate areas of a can end, which materials have differing curing temperatures, which apparatus comprises at least two stationary nozzles located at a single spray station,

means for rotating a can end relative to said nozzles at said station,

means for ejecting one of said materials as an airless liquid spray from one of said nozzles onto the bottom surface of said can end while said end is rotating at said station,

means for ejecting the other of said materials from the other of said nozzles onto the curl of said can end while said can end is rotating at said station, said other of said nozzles being a high pressure, small orifice, extrusion nozzle, and

means for sequentially exposing both of said materials on said can end within an enclosed'area to a first low temperature source of heat to cure one of said materials, and then subsequently exposing said ma terials on said can end within a second enclosed area to a second higher temperature source of heat to cure the other of said materials.

11. The apparatus of claim 10 in which said can end rotating means is operable to rotate said end about a horizontal axis at said spray station while said materials are ejected onto said rotating end.

12. Apparatus for applying can end repair coating material and sealing compound material to separate areas of a can end, which materials have differing curing temperatures, which apparatus comprises at least two stationary nozzles located at a single spray station,

means for rotating a can end relative to said nozzles at said station,

' means for ejecting said can end repair coating material as an airless liquid spray from one of said nozzles onto the bottom surface of said can end while said can end is rotating at said station,

means for extruding said sealing compound material from the other of said nozzles onto the curl. of said can end while said can end is rotating at said station, said other of said nozzles being a high pressure, small orifice, extrusion nozzle, and

means for sequentially exposing both of said materials on said can end within a generally enclosed area to a first low temperature source of heat to cure said sealing compound material, and then subsequently exposing said materials on said end to a second higher temperature source of heat to cure said end repair coating material.

13. The apparatus of claimv 12 in which said can end 14. The apparatus of claim 13 in which said sealing compound extruding means is operable to extrude said compound from the other of said nozzles at a pressure of at least 250 psi. and through a nozzle orifice of less than 0.025-inch diameter.

15. Apparatus for applying two dissimilar materials to separate areas of a can end, which materials have differing curing temperatures, which apparatus comprises at least two stationary nozzles located at a single spray station, means for rotating a can end relative to said stationary nozzles at said spray station, means for ejecting one of said materials as an airless liquid spray from one of said nozzles onto the bottom surface of said can end while said can end is rotating at said station, and means for extruding the other of said materials from the other of said nozzles onto the curl of said can end while said can end is continuing to rotate at said station, said other of said nozzles being a high pressure, small orifice, extrusion nozzle. 16. The apparatus of claim 15 in which said can end rotating means is operable to rotate said end about a horizontal axis at said spray station while said materials are ejected onto said rotating end. a: =4:

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 859 r Dated anuary 7,- 1975 Im'rentofls Richard,A. Horvath; Wm.. C. Stumphauzer, Edwin F. Hogstrom t It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

, Claim 3 Col 9 Line 63 before "end" insert ceh- Signed and sealed this 4th day of March 1975.

(SEAL) Attest: t v

t C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks USCOMM-DC 503764 69 T I Ill GOVERNMENT PIIINYING OFFICE: "I! 0-!il-JJ FORM PC2-1050 (10459)

Claims

1. THE METHOD OF APPLYING TWO DISSIMILAR MATERIALS TO SEPARATE AREAS OF A CAN END, WHICH MATERIALS HAVE DIFFERING CURING TEMPERATURES, WHICH METHOD COMPRISES ROTATING A CAN END RELATIVE TO TWO STATIONARY NOZZLES LOCATED AT A SINGLE SPRAY STATION, EJECTING ONE OF SAID MATERIALS AS A LIQUID SPRAY FROM ONE OF SAID NOZZLES ONTO LTHE BOTTOM SURFACE OF SAID CAN END WHILE SAID CAN END IS ROTATING AT SAID STATION, EJECTING THE OTHER OF SAID MATERIALS FROM THE OTHER OF SAID NOZZLES INTO THE CURL OF SAID CAN END WHILE SAID CAN END IS ROTATING AT SAID STATION, AND SEQUENTIALLY EXPOSING BOTH OF SAID MATERIALS ON SAID CAN END TO A FIRST LOW TEMPERATURE SOURCE OF HEAT TO CURE ONE OF SAID MATERIALS, AND THEN SUBSQUENTLY EXPOSING SAID MATERALS ON SAID CAN END TO A SECOND HIGHER TEMPERATURE SOURCE OF HEAT TO CURE THE OTHER OF SAID MATERIALS.

3. The method of applying can end repair coating material and sealing compound material to separate areas of a can end, which materials have differing curing temperatures, which method comprises rotating a can end relative to two stationary nozzles located at a single spray station, ejecting said can end repair coating material as a liquid atomized spray from one of said nozzles onto the bottom surface of said can end while said can end is rotating at said station, extruding said sealing compound material from the other of said nozzles into the Curl of said can end while said can end is rotating at said station, and sequentially exposing both of said materials on said end to a first low temperature source of heat to cure said sealing compound material, and then subsequently exposing said materials on said can ends to a second higher temperature source of heat to cure said can end repair coating material.

4. The method of claim 3 in which said can end is rotated about a horizontal axis at said spray station while said materials are applied onto said rotating end.

5. The method of claim 4 in which said sealing compound is extruded from the other of said nozzles at a pressure of at least 250 p.s.i. and through a nozzle orifice of less than 0.025-inch diameter.

6. The method of applying two dissimilar materials to separate areas of a can end, which materials have differing curing temperatures, which method comprises rotating a can end relative to two stationary nozzles located at a single spray station, ejecting one of said materials as a liquid atomized spray from one of said nozzles onto the bottom surface of said can end while said can end is rotating at said station, and extruding the other of said materials from the other of said nozzles into the curl of said can end while said can end is continuing to rotate at said station.

8. The method of applying sealing compound material as a thin film in the curl and beneath the curl lip of a can end, which method comprises rotating the can end at high speed about a horizontal axis relative to an extrusion nozzle, extruding said material in a generally horizontal direction at a pressure of between approximately 250 p.s.i. and 800 p.s.i. from said nozzle into the curl of said can end while said can end is rotating about said horizontal axis at said station so that material splay, gravity and centrifugal force all act to move said compound beneath a lip of said curl.

10. Apparatus for applying two dissimilar materials to separate areas of a can end, which materials have differing curing temperatures, which apparatus comprises at least two stationary nozzles located at a single spray station, means for rotating a can end relative to said nozzles at said station, means for ejecting one of said materials as an airless liquid spray from one of said nozzles onto the bottom surface of said can end while said end is rotating at said station, means for ejecting the other of said materials from the other of said nozzles onto the curl of said can end while said can end is rotating at said station, said other of said nozzles being a high pressure, small orifice, extrusion nozzle, and means for sequentially exposing both of said materials on said can end within an enclosed area to a first low temperature source of heat to cure one of said materials, and then subsequently exposing said materials on said can end within a second enclosed area to a second higher temperature source of heat to cure the other of said materials.

12. Apparatus for applying can end repair coating material and sealing compound material to separate areas of a can end, which materials have differing curing temperatures, which apparatus comprises at least two stationary nozzles located at a single spray station, means for rotating a can end relative to said nozzles at said station, means for ejecting said can end repair coating material as an airless liquid spray from one of said nozzles onto the bottom surface of said can end while said can end is rotating at said station, means for extruding said sealing compound material from the other of said nozzles onto the curl of said can end while said can end is rotating at said station, said other of said nozzles being a high pressure, small orifice, extrusion nozzle, and means for sequentially exposing both of said materials on said can end within a generally enclosed area to a first low temperature source of heat to cure said sealing compound material, and then subsequently exposing said materials on said end to a second higher temperature source of heat to cure said end repair coating material.

13. The apparatus of claim 12 in which said can end rotating means is operable to rotate said end about a horizontal axis at said spray station while said materials are applied onto said rotating end.

14. The apparatus of claim 13 in which said sealing compound extruding means is operable to extrude said compound from the other of said nozzles at a pressure of at least 250 p.s.i. and through a nozzle orifice of less than 0.025-inch diameter.

15. Apparatus for applying two dissimilar materials to separate areas of a can end, which materials have differing curing temperatures, which apparatus comprises at least two stationary nozzles located at a single spray station, means for rotating a can end relative to said stationary nozzles at said spray station, means for ejecting one of said materials as an airless liquid spray from one of said nozzles onto the bottom surface of said can end while said can end is rotating at said station, and means for extruding the other of said materials from the other of said nozzles onto the curl of said can end while said can end is continuing to rotate at said station, said other of said nozzles being a high pressure, small orifice, extrusion nozzle.

16. The apparatus of claim 15 in which said can end rotating means is operable to rotate said end about a horizontal axis at said spray station while said materials are ejected onto said rotating end.