US3716468A

US3716468A - Method for electrodeposition of cans

Info

Publication number: US3716468A
Application number: US00132857A
Authority: US
Inventors: W Chiappe
Original assignee: Continental Can Co Inc
Current assignee: Continental Can Co Inc
Priority date: 1971-04-09
Filing date: 1971-04-09
Publication date: 1973-02-13
Anticipated expiration: 1990-02-13

Abstract

A method of depositing a coating onto a can body by electrolysis in which the can bodies are forced down between spaced electrodes and a current is sent between the spaced electrodes and another electrode located at a distance from the spaced electrodes. Electric potential is applied across from the can body to the other electrode and depositing of a coating takes place.

Description

United States Patent 91 Chiappe 1 Feb. 13, 1973 METHOD FOR ELECTRODEPOSITION OF CANS [75] Inventor: Wayne T. Chiappe, Hinsdale,lll.

[73] Assignee: Continental Can Co., Inc., New

York,N.Y.

[22] Filed: April 9, 1971 [21] Appl. No.: 132,857

Related US. Application Data [62] Division of Set; No. 829,41l, June 2, 1969.

[52] U.S. Cl ..204/181 [5 1] Int. Cl ..C23b 13/00, BOlk 5/02 [5 8] Field of Search 204/18 1 [56] References Cited UNITED STATES PATENTS 3,476,666 Bell et al. ..204/ l8! Primary Examiner-l-loward S. Williams AttorneyAmericus Mitchell, Joseph E. Kerwin and William A. Dittmann 7 ABSTRACT A method of depositing a coating onto a can body by electrolysis in which the can bodies are forced down between spaced electrodes and a current is sent between the spaced electrodes and another electrode located at a distance from the spaced electrodes. Electric potential is applied across from the can body to the other electrode and depositing of a coating takes place.

10 (Ilaims, 6 Drawing Figures PATENIED 3.716.468

SHEET 10F 3 I WVENTOR WAYNE T CHIAPPE 8y JMI'QM Q A TT Y SHEET 3 [IF 3 PAIENIED FEB! 3 Ian INVENTDR WAYNE T. CHIAPPE METHOD FOR ELECTRODEPOSITION OF CANS This application is a division of pending application Ser. No. 829,411 filed, June 2, 1969, now U.S. Pat. No. 3,620,952 and entitled Mechanical Apparatus for Electrodeposition of Cans by Wayne T. Chiappe and assigned to the same assignee as the present invention.

My invention is drawn to an automatic batch electrodepositing method for cans, and specifically, a batch electrodepositing method and apparatus for depositing a coating on the can bodies.

It is an object of my invention to provide a method for automatically coating can bodies in batches.

It is another object of my invention to provide a can body feed system for isolating batches of can bodies and feeding them into, through, and out of the coating machine.

It is a final object of my invention-to provide even and regular coating of the can bodies.

In brief, my invention is drawn to the isolating of a can body or a batch of can bodies, and dipping a can or a batch of can bodies into an electroplating solution where they are plated. The edge of the can flange is rubbed against an electrode to provide electrical contact. The batch of can bodies is now air blasted to dryness, washed with deionized water, and air blasted to dryness again. After repetition of the rinsing and drying, the can body is ready for further manufacturing operations.

The above and other objects will become apparent from the following description and drawings in which:

FIG. 1 shows a front view apparatus of my invention;

FIG. 2 shows a partial top view of my apparatus;

FIG. 3 shows a cross-section of FIG. 1 taken along line 3-3 showing the discharge bar in its lower position;

FIG. 4 shows a top view of a section of the mounting plate;

FIG. 5 shows a cross-section taken along the line 5- 5 ofFIG. 4; and

FIG. 6 shows a schematic system.

My machine is adapted to be positioned in a can processing line after the can bodies have been formed. These bodies have neither top nor bottom. As shown in FIG. 1, the can body 1, after being formed, is placed upon a conveyor belt 2. The conveyor belt may be of any suitable material, such as woven mesh wire or mesh chain. Conveyor belt 2 moves the cans along to the accumulation contoured stop bar 3. Cans are then accumulated on the conveyor belt in regular patterns up to and past the feed fingers 4 and stop fingers 5. The separate bars 6 and 7 holding the feed fingers 4 and stop fingers 5 are in the raised position at this time. However, once a sufficient quantity'of cans has passed the fingers location and has filled up the conveyor beyond the area of the feed fingers and the stop fingers then the feed fingers 4 and stop fingers 5 are lowered into their respective positions in adjacent cans (FIG. 2). The accumulation contoured stop bar 3 now lifts and cans are moved forward onto the solution tank loading platform 8. These can bodies are moved by the feed fingers 4 which now move forward. The conveyor belt 2 also provides a moving support for the can bodies. After the feed fingers have moved under the accumulation contoured stop bar and the entire batch of cans is on solution tank platform 8, against the solution diagram of the control tank stop bar 9, the feed fingers are lifted to an upper position 10 and return to their original raised position. The accumulation contoured stop bar 3 returns to its lower positio'n and the stop fingers 5 are raised to allow accumulation of cans against the accumulation contoured stop bar 3. As can bodies are conducted along the processing line, this cycle is repeated time after time.

Considering now the operation of the coating bath, a batch of cans sits on the solution tank platform 8, and the platform is in its raised position. The can centering plate 11 located above the tank platform has can centering pins 13 located upon it in a regular pattern. This pattern is shown in FIG. 2. The can centering plate 11 which has been in its upper position is now lowered together with the can pressure plate 14 to a down position and respaces the cans laterally so that they do not quite touch each other. In this way, when the can bodies l are lowered into the electroplating solution 15, the electroplating solution deposits evenly on the inside and outside of the can bodies without any bare spots caused by contact between adjacent can bodies. Top plate 12 (FIGS. 1, 4 and 5) is mounted above the centering plate 11 and, as described later in this disclosure, controls operation of the can immersion. The solution tank platform 8 is made of non-metallic material and has perforations 16 at the intervals shown in FIG. 1. As the centering takes place, the stop bar 9 and side guides 17 (FIG. 2) move back to allow extra space for inter-can body distance.

After the cans have been centered and respaced, the upper centering plate remains stationary, being held in place by a stop 18. The tank plate 8 and the can pressure plate 14 are now lowered into the tank with the cans I mounted in between the plates. The can pressure plate has holes 16 in it to match the can centering pins 13. Holes 16 perform a dual function. One is to allow the centering pins 13 to protrude through them. The other function is to allow solution which passes through the tank platform to rise through the perforated tank platform into the cans and out through the can pressure plate. The holes 19 in the tank platform 8 have the dual function of allowing electrodes and solution to pass through. The cans and plates now descend onto the electrodes located in the bottom of the tank. A stationary electrode plate 20 is mounted in the tank and made of a non-conductive material, such as micarta or formica. Mounted at each station on the plate is a single cathode 21 with anodes 22 located around the cathode 20. There are as many anode and cathode stations as there are cans to be electroplated. When the can body is in its lowest position, the cathode 20 lies long the longitudinal axis of the can body and the anodes 21 touch the can with a press fit. Voltage is applied across the cathode and anodes, and the plating or electrical deposition action takes place as soon as the cans establish electrical contact with the anodes. The can in contact with each anode scrapes a portion of plating material off the anode to make electrical contact with the anode. This mechanism serves as an automatic on/off switch so that current is discharged between the cathode 21 and anode 22 only when a can body is in position to be coated and at all other times, the anode 22 is promptly recoated by electrical deposition and immediately thereafter, deposition and current flow ceases. The electric potential may be reversed from that indicated above depending on the characteristics of the coating solution. Tank platform 8 is urged into its upper position by springs or counterweights 23. A line 24 runs over one or more pulleys 25,26 and is fastened to platform 8. Theplatform is vlimited in its upward movement by stops 27. It is pushed downward by the can pressure plate 14. The can bodies are between these plates and the force imparted by the can pressure plate to the top of the can bodies is transmitted by the can bodies to the tank platform.

After the electrodeposition cycle is completed, the tank platform 8 and the pressure plate 14 move the cans upward and out of the solution and into the original upper position. The pressure plate continues its withdrawal to its high position carrying the centering plate 11 with it, and the discharge bar 28 sweeps the cans onto a second conveyor 29 made of a mesh or some other porous material. An air blast 30 from above is directed against the wet coated can bodies to remove the excess cleaning solution. The excess cleaning solution falls into a trough 31 below the conveyor and is collected for further use. As the can moves along to the next operation, a spray of deionized water is passed Y over the can bodies from a rinse water source 32. The

can bodies are rinsed with deionized water so that when they are dried, spots will not remain on the can bodies. The can bodies are dried by an air blast 33 and then are passed further along the conveyor to the next operation which may be baking in an oven 34 or some other operation in the manufacturing process.

The coating composition used in my apparatus may be a water-dispersed coating composition, such as a partially neutralized acrylic interpolymer and an amine aldehyde condensation product or a polyepoxide or both. Examples of such interpolymers are found listed in the patent to Donald P. I-Iart, U.S. PAT. NO. 3,403,088, and assigned to P.P.G. Industries, Inc.

It is noted that these protective coatings have high dielectric strength, coat metallic articles completely, have efficient electro-depositing qualities, and result in cured films which are clear, glossy and have attractive appearance and good durability.

A cross-section through the solution tank 35 is shown in FIG. 3. The discharge bar 28 is shown in its lowered position where it pushes cans off of the perforated tank platform 8 onto the conveyor belt. The stationary electrode plate 20 is shown with one of the numerous electrode stations in some detail. Attached to the bottom of the electrode stations at each station are

conductive wires

36,37, which are themselves coated with a plastic or other coat 39 to avoid electrical loss because of short circuiting the electric current through the solution with consequent loss of electric current and usable solution.

Threaded bolts 40 thread into nut 55 in the top plate 12 and are immovably fastened into pressure plate 14 (FIGS. 4 and Rotation of these threaded bolts or screws causes the can body pressure plate 44 to move upward or downward because of threaded elements fastened to the top plate. The electrical reversing motor 45 causes the chain to turn the sprockets and rotate the screws.

The motor 45 is controlled by the same master circuit that controls the motors of the various bars and plates as shown in FIG. 6. In any case, this motor drives a chain 46 around the first sprocket wheel 47, around an idler 48, the second sprocket wheel 49, third sprocket wheel 50, second idler 51, fourth sprocket wheel 52, and back around the motor drive gear 53. The idler pulleys 48,51 may be moved in and out individually to adjust the tension on the chain 46. Four posts 54 or guide rods are fastened to the plate 12 and to the tank to support the top plate and provide guides for the movable plates. The electrical reversing motor 45 is used to turn the

sprockets

47, 49, 50 and 52, and the attached threaded nuts clockwise and counterclockwise to move the pressure plate up or down. The position of the motor 45, guide shafts 40, idler 48, and drive sprocket 49 and nut 55 are shown best in FIG. 5.

A schematic control box 56 with appropriate motors is shown in FIG. 6.. Each of the motors 45i-and 57-61 is operated by the control box to start and stop in accord with the schedule set up in the description of operation and the tabular statement below. In this way, the bars, plates and side guides are operated at the appropriate time.

To summarize the operation of the machine, the following operational sequence is provided:

First, flanged can bodies are manufactured or otherwise provided in plate position on the first wide conveyor belt or other type of conveyor. The conveyor belt is continually moving.

Second, the cans come to rest against the accumulation contoured stop bar and back up in a pattern.

Third, after the pattern is filled, stop fingers and feed pins are lowered into the cans.

Fourth, the pattern forming head stock or contoured accumulation stop bar is raised and the feed finger bar sweeps the can bodies off onto the solution tank platform and across to the solution tank stop bar.

Fifth, the feed bar raises and returns to its can body accumulating position in its raised position.

Sixth, the can pressure plate and can centering plate lower to a point short of touching or clamping the cans.

Seventh, the can centering plate continues to lower with centering pins entering inside the can bodies to provide can body spacing. Simultaneously, stop bars swing away and side guides are opened up sufficiently to allow a new pattern space so that liquid can swirl up between the cans.

Eighth, the can body pressure plate moves down and drives the can bodies on the tank platform into the lowered deposition position in the tank, the can flanges shear into the anodes located on the non-conductive electrode plate.

Ninth, the coating solution and electric current operate to coat the cans.

Tenth, after the cans are coated, the can pressure plate is raised and the solution tank platform follows it up until the solution tank platform is in its high position.

Eleventh, the tank platform being at its discharge position, the discharge sweep bar now lowers and sweeps the coated cans onto the second or discharge conveyor and the sweep bar now returns to its holding position. The total time cycle is about 38 seconds. It is, of course, realized that this cycle may be varied comprising the steps of:

blowing air along the longitudinal axis of said can whereby liquid is removed from said can body, spraying deionized water over surfaces of said can body, and

blowing air along the longitudinal axis of said can whereby liquid is removed from said can body. 6. A method of electrodepositing a coating solution onto a flanged can body comprising the steps of:

mounting a plurality of elongate electrodes each having a straight edge with their long axes parallel to each other and their long axes lying at the periphery of a circle of about the size of the diameter of the edge of said flanged can body;

mounting further electrode means equidistance of said elongate electrodes;

placing said elongate electrodes and said electrode means into a solution having electrodepositing material therein;

applying an electric potential across said plurality of elongate electrodes and said electrode means located in said solution;

forcing the flanged can body between said spaced elongate electrodes, whereby said elongate electrode straight edges and flanged can body scrape together to form at least one electrical contact; and

removing said flanged can bodies from said coating solution.

7. A method of electrodepositing a coating solution onto a flanged can body as set forth in claim 6 in which. the step of forcing said flanged can comprises the steps of:

pushing said flanged can body between the straight edges of the elongate electrodes whereby the edges of the flange of said can body touches each said straight edge; and

within scraping the flange of said can body against each straight edge of each said elongate electrode whereby an electrical contact is established between said can body and said elongate electrode.

8. A method of electrodepositing a coating solution onto a flanged can body as set forth in claim 7 in which the step of raising said flanged can body comprises the steps of:

lifting said flanged can body from between said elongate electrodes whereby the flange and elongate electrodes are electrically disconnected and said coating material coats the bare spot on said elongate electrode to stop the flow of electricity between said elongate electrode and said further electrode means.

9. A method of electrodepositing a coating solution onto a flanged can body as set forth in claim 6 in which the step of lowering a flanged can body into a solution comprises the steps of:

orienting said can body with its long axis perpendicular to the surface of said coating solution;

lowering said can body directly into the coating solution whereby turbulence and bubbles are minimized.

10. A method of electrodepositing a coating solution onto a flanged can body as set forth in claim 6 further comprising the steps of:

blowing air along the longitudinal axis of said can whereby liquid is removed from said can body, spraying deionized water over surfaces of said can body; and

blowing air along the longitudinal axis of said can whereby said water is removed from said can body.

Claims

1. A method of electrodepositing a coating solution onto a flanged can body comprising the steps of: lowering a flanged can body into a solution having an electrodepositing material therein; applying an electric potential between a plurality of anodes and a cathode located in said material; forcing the flanged can body down between spaced vertical anodes, whereby at least one anode and flanged can form an electrical contact; and raising said flanged can bodies from said coating solution.

2. A method of electrodepositing a coating solution onto a flanged can body as set forth in claim 1 in which the step of forcing said flanged can comprises the steps of: pushing said flanged can body between the anodes whereby the flange of said can touches each said anodE; and scraping the flange of said can body against the side of each said anode whereby an electrical contact is established between said can body and said anode.

3. A method of electrodepositing a coating solution onto a flanged can body as set forth in claim 2 win which the step of raising said flanged can body comprises the steps of: lifting said flanged can body from between said anodes whereby the flange and anode are electrically disconnected and said coating material coats the bare spot on said anode to stop the flow of electricity between said cathode and said anode; and lifting said flanged can body to a position above said solution.

4. A method of electrodepositing a coating solution onto a flanged can body as set forth in claim 1 in which the step of lowering a flanged can body into a solution comprises the steps of: orienting said can body with its long axis perpendicular to the surface of said coating solution, lowering said can body directly into the coating solution whereby turbulence and bubbles are minimized.

5. A method of electrodepositing a coating solution onto a flanged can body as set forth in claim 1 further comprising the steps of: blowing air along the longitudinal axis of said can whereby liquid is removed from said can body, spraying deionized water over surfaces of said can body, and blowing air along the longitudinal axis of said can whereby liquid is removed from said can body.

6. A method of electrodepositing a coating solution onto a flanged can body comprising the steps of: mounting a plurality of elongate electrodes each having a straight edge with their long axes parallel to each other and their long axes lying at the periphery of a circle of about the size of the diameter of the edge of said flanged can body; mounting further electrode means within equidistance of said elongate electrodes; placing said elongate electrodes and said electrode means into a solution having electrodepositing material therein; applying an electric potential across said plurality of elongate electrodes and said electrode means located in said solution; forcing the flanged can body between said spaced elongate electrodes, whereby said elongate electrode straight edges and flanged can body scrape together to form at least one electrical contact; and removing said flanged can bodies from said coating solution.

7. A method of electrodepositing a coating solution onto a flanged can body as set forth in claim 6 in which the step of forcing said flanged can comprises the steps of: pushing said flanged can body between the straight edges of the elongate electrodes whereby the edges of the flange of said can body touches each said straight edge; and scraping the flange of said can body against each straight edge of each said elongate electrode whereby an electrical contact is established between said can body and said elongate electrode.

8. A method of electrodepositing a coating solution onto a flanged can body as set forth in claim 7 in which the step of raising said flanged can body comprises the steps of: lifting said flanged can body from between said elongate electrodes whereby the flange and elongate electrodes are electrically disconnected and said coating material coats the bare spot on said elongate electrode to stop the flow of electricity between said elongate electrode and said further electrode means.

9. A method of electrodepositing a coating solution onto a flanged can body as set forth in claim 6 in which the step of lowering a flanged can body into a solution comprises the steps of: orienting said can body with its long axis perpendicular to the surface of said coating solution; lowering said can body directly into the coating solution whereby turbulence and bubbles are minimized.