US 2506794 A
Description (OCR text may contain errors)
May 9, H950 J. M. KENNEDY ET AL APPARATUS FOR ELECTROPLATING Filed Nov. 23, 1945 6 Sheets-Sheet l 88. Maw 09% s.
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6- Sheets-Sheet 3 9, 1950 J M KENNEDY ET AL APPARATUS FOR ELECTROPLATING Filed Nov. 2", 1945 May 9, 3950 J. M. KENNEDY ET AL APPARATUS FOR ELECTROPLATING Filed Nov. 23, 1945 6 Sheets-Sheet 4 A NWQWN hi ZV M m nh $1M W .W I ma m 5 5 5 W M m y y 0 .1. M. KENNEDY ET AL 2,506,794
APPARATUS FOR ELECTROPLATING 6 Sheets-Sheet 5 acoo- A i v 4 I39 7 pan-we 0e acac an- I nveni/ons: Jams MKezzne i d1 rihurPKn/igh May 9, 1950 J. M. KENNEDY ET AL APPARATUS FOR ELECTROPLATING Filed Nov. 23, 1945 6 Sheets-Sheet 6 Q Irv/2192123021; Jamafllfenmdy oumnuuL Patented May 9, 1950 UNITED STATES TENT OFFICE APFARATUS FOR ELECTBOPLATING ration of Maryland Application November 23, 1945, Serial No. 630,266
Our invention relates to methods of and apparatus for electroplating.
The invention has among its objects cladding the bottom portion of a cooking vessel or the like with a coating of metal such as copper, with provision for forming the coating with a marginal portion of gradually decreasing thickness as the edge of the coating is approached. From this aspect the invention constitutes an improvement in the method of electrodepositing the relatively thick copper coating according to the disclosure of applicants Patent 2,363,973, issued November 28, 1944, and relates to apparatus for the practice of such improvement.
The invention, however, will be best understood from the following description when read in the light of the accompanying drawings of several embodiments of apparatus according to the invention, the scope of which latter will be more particularly pointed out in the appended claims.
In the drawings:
Fig. 1 is a transverse section of plating apparatus according to the invention, corresponding to a section on the line l-l of Figs. 6, 7 and 8;
Fig. 2 is a section on the line 2-2 of Fig. 1;
Fig. 3 is a fragmentary section, on an enlarged scale, on the line 33 of Fig. 6;
Fig. 4 is an elevation of a fragment of the chain for moving the article carriers;
Fig. 5 is a plan of the chain according to Fig. 4;
Fig. 6 is a plan of a fragment of the plating apparatus according to Fig. 1;
Fig. 7 is a plan, on a reduced scale, of the plating apparatus according to Figs. 1 and 6, with parts broken away and parts omitted, including a schematic diagram of the control mechanism;
Fig. 8 is a longitudinal section of plating apparatus according to Figs. 1, 6 and 7, with parts in elevation and parts broken away;
Figs. 9 and 10 are more or less diagrammatic views illustrating the arrangement of carrier supports according to Figs. 1 to 8;
Figs. l1, l2 and 13 are, respectively, sections on an enlarged scale on the lines H-l l, l2- l2 i3l3 of Fig.7;
Fig. 14 is a side elevation of the apparatus according to Figs. 1 to 13, with parts omitted and parts broken away;
Fig. 15 is a section on the line l5i 5 of Fig. 14;
Fig. 16 is a fragmentary transverse section of a modified form of apparatus, corresponding to Fig. 1, with parts omitted;
Fig. 17 is a fragmentary plan of the apparatus according to Fig. 16 illustrating a detail;
Fig. 18 is a fragmentary side elevation of the apparatus according to Fig. 16, with parts omitted, more or less diagrammatically illustrating a portion of the article carrier support;
Fig. 19 is a fragmentary transverse section of a further modified form of apparatus, corresponding to Fig. 1, with parts omitted;
Fig. 20 is a section on the line 2l32ll of Fig. 19;
Fig. 21 is a fragmentary side elevation of the apparatus according to Fig. 19, with parts omitted and parts broken away, more or less diagrammatically illustrating a portion of the article carrier support;
Fig. 22 is a fragmentary section, on an enlarged scale, of the lower corner portion of the vessel according to Fig. 2 showing an electrodeposited plating or coating applied thereto; and
Fig. 23 is a modified form of vessel, according to Fig. 22, showing an electrodeposited plating or coating applied thereto.
Referring particularly to the modification of the apparatus illustrated by Figs. 1 to 14, an elongated tank I, preferably formed of lead coated steel, is adapted to contain a body of electrolyte the upper surface level of which is. indicated at L (Fig. 1). As shown, in this electrolyte are immersed the lower portions of cooking vessels or like articles A, the bottom portions of which are to be clad with a relatively thick coating of metal such as copper.
The upper edges of the tank are shown as provided with longitudinally extending horizontal flanges 3 upon which, at each of opposite longitudinal sides of the tank, rests a strip 5 of insulating material such as fiber. Supported on these strips are bus-bars 1 preferably of copper. For securing the bus-bars and insulating strips to the flanges are shown bolts 9 extending from the lower sides of the flanges through the strips -5 and tapped into the bus-bars l, the bolts being insulated from the flanges by the insulating bushings II. Connected to the outer edges of the bus-bars l, as by brazing or welding, are cable lugs 13 to which are connected the cables [5 and ii for connecting the bus-bars to the opposite terminals, respectively, of the source of current supply.
As shown, connected to the inner edge of one of the bus-bars l, as by brazing or welding, are the upper ends of the downwardly directed portions IQ of bars having horizontal portions 2| submerged in the electrolyte, these horizontal portions extending transversely across the tank.
As shown, the bars i9, 2| are supported on suitable brackets 23 carried by the side walls of the tank, which brackets are also preferably lead covered to render them inert with respect to the electrolyte. Carried by the horizontal portions 2! of each of the bars are shown a pinrality of spaced anodes, herein two. These anodes, as illustrated, comprise annular trays 25, preferably formed of lead or other conductive material inert with respect to the electrolyte, which trays are filled with a mass 21 of copper shot or the like forming a readily replenishable or renewable soluble anode.
The above mentioned trays 25 are shown as resting upon disks 29, preferably formed of copper and welded to the upper side of the bar portions 2!. As shown, each disk is formed with an upwardly projecting nipple 3-! received in the opening of the annular tray 25. As illustrated, the nipple and disk are formed with an opening 33 which is continued to the under side of the bar portion 2!. In the upper end of this opening is screw-threaded a nozzle 35 formed of hard rubber or other suitable insulating material, the edge of the nozzle overlying the edge of the annular tray 25 so that the nozzle secures it to the disk 25 in electrical contact therewith.
As shown, each nozzle 35 is provided with a group of upwardly directed openings 31 (Fig. 6) for projecting electrolyte upward toward the bottom of the vessel A, and with distributed radially directed openings 39 (Figs. 1 and 6) for proiecting electrolyte in all directions radially of the bottom of the vessel. For supplying electrolyte under pressure to the nozzle, screw-threaded into the lower ends of the opening 33 is shown a pipe connection 4|, preferably formed of lead, which is connected by a length of rubber hose 43, or conduit of other insulating material, to the outlet nipples 65 of a lead pipe 4! extending longitudinally of the tank. As shown (Fig. 7) this pipe has a portion 39 connected to the outlet of a motor driven pump 5| at the exterior of the tank, the inlet of the pump being connected to the tank by a pipe 53 so as to draw electrolyte therefrom and supply it to the pipe 49, in which way the electrolyte is circulated.
Supported on posts 55 (Figs. 1 and 3) carried by the bar portions 2| are ring members 51 having flanged radially extending portions 59, upon which latter rest annular metal shields 6i positioned between the anodes and the peripheral portions of the vessels. As shown, the exposed portions of the bar portions 2|, disks 29, posts 55, ring members 51 and shields Bl are covered with a layer 63, of rubber or other insulating material, for protecting and insulating them the electrolyte. As shown, the shield is removable so that shields with different size openings 6 may be substituted to accommodate vessels of different diameters.
The above described nozzles 35 and shields G! are identical with those disclosed in the above mentioned patent, and are arranged dimensionally with relation to each other and the anode and vessel as therein shown and described, and serve the same purpose. Briefly; this purpose is by use of the nozzle to permit, in conjunction with the rotating vessel, a higher current density per unit of cathode surface and eliminate the possibility of quiescent spots in the electrolyte at the axial portion of the bottom of the rotating vessel, while the shield causes the path of travel of the plating current from the anode to the vessel progressively to increase from points opposite the inner peripheral edge of the annular shield to the edges of the surface being plated, hence to cause the value of the current and consequent rate of deposition progressively to diminish from points opposite the inner peripheral edge of the shield to the edge of the surfaces being plated as compared to what they would be were the shield omitted.
As shown, the vessels A are supported by carriers comprising the spaced bars 65 which are preferably formed of metal such as brass and are integrally connected at their ends by cross-bars 61. As shown, at the intermediate portions of the carrier are cross-bars 69 integrally formed with the bars 55. These bars 69 have depending portions 7! which are perforated for fixedly carrying elongated sleeves 13, in which latter are rotatably mounted vertical shafts 15. As shown, carried by the lower end of each shaft 15 is a chuck for supporting the vessel A. The chuck, which is preferably formed of resilient sheet copper, has a bottom 71' to which the shaft 75 is joined, as by welding, and has side walls formed with l -shaped splits 19 to form a circular series of spaced resilient prongs 8|, the latter engaging the lower portions of the side walls of the vessel for supporting it and detachably connecting it to the shaft 15. As shown, each shaft 15 is provided at its upper end with a bevel gear 83 meshing with a bevel gear 85 on a horizontal shaft 81 rotatably supported in bearings 89 on the carrier crossbars 69. The shaft 81 is shown as connected by an insulating coupling 9! to an electric motor 93 for driving said shaft, the motor being supported on a plate 95 of insulating magerial carried at opposite ends by the side bars For energizing the motor 93 the plate 95 of insulating material which supports it carries a pair of downwardly projecting brushes 97 connected by leads 98 (Fig. l) to the motor terminals. These brushes have contact portions 93 engaging the flat bar-like trolley wires H]! extending longitudinally of the tank. As shown. these trolley wires are carried by brackets Hi3 supported by the adjacent side wall of the tank, insulating strips 95 being positioned between the wires and the brackets, these bars and strips being conveniently secured to the brackets in the same way as the bus-bars l and insulating strips 5 are secured to the tank flanges 3. The brushes 9'! are of a known type in which the contact portions 99 are yieldingly extensible relative to the body of the brushes so as to maintain contact with the trolley wires when the carrier is slightly raised, as will be hereinafter described. The trolley wires may be connected to a suitable source of electromotive force by leads indicated at it? (Fig. 7).
As shown, the bus-bar 1 at the left hand side of the tank, as viewed in Figs. 1 and 6, is provided with raised portions in the form of plates I09, preferably of copper, of progressively increasing thickness from one end of the tank to the other, as illustrated in Figs. 8 and 9, these plates being secured to the bus-bar in any convenient way as, for example, by screws l i I (Figs. 11 and 12) or by welding or brazing, so that the plates will be in electrical communication with the bus-bar. As shown, the carrier is provided with a cross-bar H3 having a depending portion H adapted to rest upon these plates. This cross-bar is integral with the carrier side bars 65, and as the cross-bars 69 are also integral with those side bars, and the shafts 15 are in electrical communication with the metal sleeves I3 supported by'the cross-bars 59, the vessels A are electrically connected to the bus-bar I when the cross-bar H3 rests upon any of the plates Hi9.
For supporting the carriers at the side of the tank opposite the plates I89 is provided a horizontal rail l i 5 coextensive with the length of the tank. This rail, as shown, is carried by spaced brackets Ill, and on the rail are plates N9 of insulating material, which plates are positioned directly opposite the plates Hi9 and are of the same thickness as the latter. The carrier crossbar 6? adjacent the rail H5 has a depending portion i2I similar to the depending portion N4 of the cross-bar H3 at the opposite side of the tank, which depending portion l2i is adapted to rest upon these plates H9.-
Supported by each of the brackets II"! at opposite sides of the tank isa rail I23 coextensive with the length of the tank. At each end the carrier is provided with a pair of wheels 25 1 adapted to ride on these rails when the carrier is moved off t-e plates i533 and H9, these plates lifting the wheels of)? the rails when the carrier is moved to position it on the plates. As a result the wheels ride on the rails only when the carrier is being moved lengthwise of the tank from one pair of these plates to the adjacent pair. As will be clear from Fig. 8, the rails I23 are upwardly inclined from one end of the tank to the other so that the plates at each station. will raise the wheels of the carrier approximately the same distance from said rails. As shown, the body portion i2? (Fig. 6) of the wheels 525 is formed of insulating material so that the rails 523 are insulated from the carrier.
It will be understood that by the above construction the plates Hi9 and M9 being of progressively increasing thickness cause the depth of immersion of the vessels A to be progressively decreased as they are progressively placed over difierent anodes by moving the carrier lengthwise of the tank to place them on different plates. The hei hts of the upper surfaces of the plates may be readily varied by machining off those surfaces or by building them up or substituting difierent plates, so as to compensate for settling or warping of the tank and for controlling the depth of immersion of the vesselswhile over the respective anodes.
For moving the carriers lengthwise of the tank the cross-bars 57 at opposite of the carrier are shown as provided with projecting bar-like members I29 formed of insulating material. Extending lengthwise oi the rails is shown a chain I the upper run of which is positioned beneath these members. This chain is of usual construction except that pairs of opposite side links I33 at spaced points along the chain have upwardly projecting portions 35 (Figs. 1, l, 5, and 14) which are adapted to engage with the members lZQ of the carriers when the chain i moved. By moving the chain intermittently it in this way is efiective to push the carriers to position the vessels carried thereby successively over consecutive anodes. As illustrated, the chain passes around sprocket wheels it! carried by the brackets ii? at opposite ends or" the tank. The portion of the upper run of the chain between these sprocket wheels is supported by flanged wheels 35 carried by the intermediate brackets IiI, while the lower run. of the chain is supported by sprocket wheels Mi (Fig. 14%) also carried by the intermediate brackets i ll. As illustrated in Figs. 14 and 15, the sprocket wheels MI are so designed that they may enter the spaces between the projections I35 at opposite sides of the chain so as to engage with the body of the latter.
As shown, the chains I3I at opposite sides of the tank are each driven by a chain Hi3 (Fig. '7) having a sprocket wheel connection with a common shaft I45, so that the chains I3I will be driven in unison. For driving the shaft I 45 is provided an electric motor I41 adapted to be connected in driving relation to the shaft through an electro-magnetically controlled clutch, the clutch elements of which latter are schematically indicated at I49 and the energizing winding at I5I. The clutch as shown is indicated in open position so that the chains ISI will be stationary while the articles are over the anodes. Conveniently the motor is connected to the clutch through a reduction gearing, the casing of which is indicated at I53. For intermittently energizing and deenergizing the winding IEI of the clutch, so as intermittently to open and close the latter, is provided a synchronous motor sche matically indicated at i555, which motor slowly turns a disk I51 of insulating material connected to the motor through a reduction gearing the casing of which is indicated at I59. As shown, the disk is provided at its periphery with a segment SI of conductive material adapted intermittently to contact with a brush I63 connected to one terminal of the clutch energizing winding I5I, the other terminal of which winding is connected to one side I65 of a line for energizing this winding. The other side I51 of this line is connected to a brush H59 contacting with a ring I II of conductive material carried by the disk I51, which ring is connected by a lead I73 to the conductive segment IEI on the disk. As a result, when the disk is slowly rotated to cause the brush I63 to contact with the segment It! the winding I5I of the clutch will be energized to cause the clutch to close, and, while it is closed, the motor I4! will move the chain to cause the carriers to be transferred from over one set of anodes to the immediately adjacent set. The angular length of the segment is so designed with relation to the speed of the disk I51 that the chain will stop moving as soon as the carriers are placed above each set of anodes.
For supplying the plating current is shown a generator I75 the opposite terminals of which are connected by l ads IT! to the opposite busbars 1, respectively. These bus-bars preferably are not continuous, but are formed in sections connected to the generator terminals in parallel so that the amount of current carried by each section will be reduced. As indicated in Fig. 7, the adjacent ends of these sections are separated by insulating blocks H9. As schematically shown inFig. '7, the field winding of the generator is provided with a voltage control section I8I controlled by a switch 683 adapted to be operated by a solenoid I connected in series relation with the winding Hit of the electro-magnetic clutch, so that when this latter winding is energized the solenoid will be simultaneously energized to cause the switch M3 to close and thus reduce the voltage of the generator to a low value. This provides that when the clutch is closed to cause the carriers to be moved the plating current is substantially interrupted and will not be again established until the chain ceases to move, so that arcing will not occur.
As pointed out in applicants patent above referred to, it is of importance, in plating the lower portion of a cooking vessel with a relatively thick layer of copper or. other metal for distributing the heat applied to the vessel, to have the marginal portions of the plating gradually taper to a feather cedge merging into thesurface ofthe base metal. Although-excellent results in these respects may be secured by use of the shield above mentioned, it has been found that improved results can be secured bygradually decreasing the immersion of the vessel as the plating operation is continued. Fol-example, if the vessel A (Fig. 22) is initially immersed for a depth of about by gradually decreasing the depth of immersion to about the tapered portion I81 of the plated layer I89 may be much more readily secured and'its shape readily controlled. Various shapes of vessels may .be readily plated in this way as, for example, the approximately square cornered vessel AA shown in Fig. 23, with which shape of vessel the opening in the annular shield 6I is-preferably so designed as to cause the plating layer [9| to bulge considerably adjacent the corners of the vessel, as indicated at I93, so as to protect the plating from injury at the corners of thevessel during handling of the latter when subjected to use in the kitchen.
It has been found, for example, that in cladding a cooking vessel .of the shape shown by Fig. 22 or 23 and of material ,such as stainless steel, aluminum, or iron requiring, or improved by, .a copper cladding for distributing the heat, satisfactory results commonlywill be secured with a cladding about 0.03" thick on the bottom of the vessel, and that a satisfactory tapered layer can be secured by causing the cladding to be plated in eighteen steps, each electrodepositing on the bottom of the vessel a layer about 0.0017 thick. With a current density of about350 amperes per square foot of cathode surface and a sulphuric acid electrolyte consisting of about by weight of sulphuric acid and by weight of copper sulphate such a layer may be deposited in about 5 minutes. In this operation the vessels may be rotated at such linear speed at the major diameter of theimmersed portions as corresponds to about 250 R. .P. M. for a vessel 7 inches in diameter. At this speed a thin film of electrolyte is drawn up the walls of the vessel for about above the normal electrolyte level, and due to the attenuation of this film the deposition of copper from it proceeds at a very slow rate as compared to the rate of deposition on the bottom of the vessel. This results in the metal deposited from the film-merging into the surface on which it is deposited. It will be understood that by progressively decreasing the immersion of the article the marginal portion of the layer deposited on the vessel when it is over each anode will overlap with the marginal portion of the layer deposited when it is over the preceding anode. For example, if the depth of immersion is decreased %"'in eighteen equal steps as above described, each layer will overlap the other about 0.02. So as to have the rate of deposition at each station approximately the same, the anodes preferably are positioned progressively at a higher elevation as the row of anodes progresses lengthwise of the tank, so as to have them in approximately the same relation to the bottom of the vessel as the depth of immersion of the latter is progressively decreased. In cladding the vessel according to Fig. 22, satisfactory results will be secured with the current density, electrolyte concentration, and speed of rotation of the vesseL-above mentioned,
when the upper level of the :copper shot in the anodes is spaced about Zinches from the bottom of the vessel and the shield is spaced about 1 inch from the bottom of the vessel, the shield having an openingapproximately 1 to 2 inches less than the diameter of the vessel, and with about 5 gallons of :electrolyte per minute discharged through each nozzle, the radial openings 39 of the nozzle being about 1% inches below the bottom of the vessel.
In operation the carriers may be placed above the anodes at the first station in the tank, and may be removed from the anodes at the last station, by suitable conveyer means of a known type, these conveyer means preferably liftin the carrier by engagement with the projecting members I29 at each end thereof.
It will be understood that preliminary to the plating operation above described the vessel may be subjected to such treatment as is necessary to prepare it for such plating. For example, if the vessel is a stainless steel cooking vessel, it may be subjected to the preliminary treatment described in applicants above mentioned patent, namely, roughening the surface to be plated by an anodic treatment 01' otherwise, treating the roughened surface with electrolytically released hydrogen by making said surface a cathode in a non-metal bearing sulphuric acid electrolyte, and applying a flash coating to the cathodically treated surface. These operations consume but a relatively short period of time, with the result that vessels will be ready to be placed in the plating tank above described about every 6 minutes. The vessels may be loaded on the carrier before subjecting them to these preliminary treatments, and the carriers moved from tank to tank where such treatments are performed, and upon completion of these treatments may be moved immediately by the above mentioned conveyer to the first station of the plating tank above described. Therefore, by having a number of stations in the plating tank, in which the vessels remain a relatively longtime, a continuous operation may be readily performed. For example, a loaded carrier may be started about every 6 minutes through the apparatus for performing the preliminary treatment of the vessels, and substantially immediately upon the completion of the operation of depositing the flash coating, that is to say about every'6 minutes, a loaded carrier may be placed at the first station in the plating tank, and then every 6 minutes the carrier may be moved to the next successive station in the plating tank, the carrier remaining at each station about 5 /2 minutes. In this way a row of carriers will be maintained in the plating tank, the end carrier of the row being removed from the tank in this example every 6 minutes.
In the form of apparatus shown by Figs. 19 to 21, the wheels I25 of the carriers remain continuously on the rails I23, the raised plates I63 and H9 being omitted. In this modification the cross-bar II3 carries a brush i515 continuously in contact with the adjacent bus-bar I. As shown, this brush has rigidly secured thereto bolts I91 secured at their lower ends into the brush and slidably extending through openings I99 in the cross-bar, which openings they fit with sufficient tightness to place them in electrical communication'with the'cross-bar so as to conduct current from the bus-bar to the carrier. As shown, the brushes are maintained in contact with the bus-bar by springs 20I received in openings 203 in the cross-bar and hearing at their lower ends against the brushes. As shown, the rails I23 are upwardly inclined. from one end of the tank I to the other, so that the carrier as it is moved from one anode station to the other is progressively raised for decreasing the depth of immersion of the vessels.
In the modification shown by Figs. 16 to 18 the cross-bar H3 of the carrier permanently contacts with the adjacent bus-bar I, while the insulating plate 95 which, as shown in Fig. 1, supports the motor 93 and brushes 91, is provided with a downwardly projecting portion 205 which rests upon the adjacent bus-bar I, so that the carrier is supported on these two bus-bars. For raising the carrier as it travels along the tank, so as to vary the depth of immersion, the two bus-bars I, as shown in Fig. 18, are upwardly inclined from one end of the tank to the other, being for this purpose supported on an insulating strip 291, which strip is like the insulating strip 5 of Fig. 1 except that it is of progressively increasing thickness as it extends from one end of the tank to the other.
In this last mentioned modification each of the projecting members I29 at the opposite ends of the carrier is provided, on the side thereof engaged by the spaced pairs of projections I35 of the chain, with a block 209 adapted to be embraced by the adjacent pairs of projections when the latter engage with said member. This construction causes the projections on the chains to hold the carriers against substantial endwise movement on the bus-bars I. For facilitating entry of the blocks 299 into the spaces between the chain projections I35 when the carriers are initially placed over the tank, the upper ends of said projections are shown at 2H as bent outwardly to dorm a. flared opening between them.
It will be understood that within the scope of the appended claims wide deviations may be made from the forms of the invention herein described without departing from the spirit of the invention.
1. In an apparatus for electrodepositing on bottom and side wall portions of the outer surface of revolution of a metal cooking vessel, a metallic coating which on said side wall portions is of gradually decreasing thickness as it approaches its upper edge portion and merges at its upper edge portion into said surface, which apparatus comprises a tank adapted to contain electrolyte at a predetermined level, a depending rotatable chuck for supporting the vessel, a traveling supporting carrier for the chuck, guide and supporting means for said traveling carrier, said guide and supporting means including :progressively elevated portions formed at spaced intervals, automatic means for intermittently moving said carrier to said progressively elevated portions to position said chuck at predetermined levels with respect to the electrolyte in said tank, power driving means for rotating said chuck mounted on said traveling carrier, and means for supplying power to said power driving means at said spaced progressively elevated portions.
2. The apparatus according to claim 1 in which electrical contact elements are arranged at the spaced elevated portions, the carrier including means constituting an electrical contact which when the carrier is at each oi said elev ated portions forms an electrical contact with the contact element thereat, and means comprising parts of conductive material of the chuck in electrical communication with the contact of the carrier for making the vessel a cathode while at each elevated portion.
3. The apparatus according to claim 1 in which the spaced elevated portions for the carrier each includes means constituting an electrical contact, the contact at each spaced portion being at a higher level than the contact at the preceding spaced portion, the carrier being of conductive material whereby when it rests on the contact of a spaced |portion it is \placed in electrical communication therewith, the chuck having a shaft of conductive material rotatably supported on the carrier and in electrical communication therewith, and the chuck being of conductive material in electrical communication with said shaft, whereby when the carrier is supported upon said spaced portions the vessel is placed in electrical communication with the contacts of said portions for making it a cathode.
4. In an apparatus for electrodepositing on the bottom and side wall portions of the outer surface of revolution of a metal cooking vessel, a metallic coating which on said side wall portions is of gradually decreasing thickness as it approaches its upper edge portion and merges at its upper edge portion into said surface, which apparatus comprises a tank adapted to contain electrolyte at a predetermined level, a depending rotatable chuck for supporting the vessel, a traveling supporting carrier for the chuck, a series of anodes in said tank in spaced relation to each other, supporting means for said traveling supporting carrier adj acent each of the sev eral anodes of said series, said supporting means being at progressively greater predetermined elevations in the direction of travel of said travel ing supporting carrier, power driven means for automatically intermittently moving said traveling supporting carrier successively onto said progressively elevated supporting means for positioning said chuck successively above the several anodes of said series at \progressively increasing predetermined elevations with respect to such electrolyte, power driving means mounted on said supporting carrier for rotating said chuck. and means for supplying power to said power driving means when said traveling supporting carrier is supported by said supporting means.
JAMES M. KENNEDY. ARTHUR P. KNIGHT. HAROLD J. LEE.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 75,258 Forbes Mar. 10, 1868 234,775 Herskell Nov. 23, 1380 1,298,155 Anthony Mar. 25, 1919 1,453,419 Thompson May 1, 1923 2,044,431 Harrison June 16, 1936 2,098,813 Rosseau Nov. 9, 1937 2,138,938 Plenrsler Dec. 6, 1938 2,363,973 Kennedy et al Nov. 28, 1944 FOREIGN PATENTS Number Country Date 4,120 Great Britain of 1897 17,717 Great Britain of 1907