US2240265A - Method of continuously tin plating ferrous metal stock - Google Patents

Description

April 29, 1941.

J. S. NACHTMAN METHOD OF CONTINUOUSLY TIN PLATING FERROUS METAL STOCK Filed March 30, 1937 8 Sheets-Sheet l J. S. NACHTMAN April 29, 1941.

METHOD 0? CONTINUOUSLY TIN PLATING FERROUS METAL STOCK Filed larch 30. 1937 8 Sheets-Sheet 2 April 29, 1941. J. s. NACHTMAN 2,240,265 METHOD OF CONTINUOUSLY L'IN PLATING FERROUS METAL STOCK 8 Sheets-Sheet 3 Filed larch 30, 1937 April ,1 J. s. NACHTMAN 2,240,265

- METHOD OF CONTINUOUSLY TIN PLATING FERROUS METAL STOCK Filed larch 30. 1957 8 Sheets-Sheet 4 J. S. NACHTMAN April 29, 1941.

METHOD Of CONTINUOUSLY TIN PLATING FERROUSMETAL STOCK 8 Sheets-Sheet 6 Filed March 30, 1937 R, U I I I IHHI I I I IUIHU HHIHI IH IHHHI I I IHH HHU HHHH IUHHI I I IU U r I I HHI M HH IH IUHHH IU $8 J. S. NACHTMAN Apl il 2.9, 1941.

METHOD OF CONTINUOUSLY TIN PLATING FERROUS METAL STOCK Filed Iarch 30. 1937 8 Sheets-Sheet 7 April 1941- J. s. NACHTMAN 2,240,265

- METHOD OF CONTINUOUSLY TIN PLATING FERROUS METAL STOCK Filed March 30, 1937 8 Sheets-Sheet 8 Patented Apr. 29, 1941 METHOD OF CONTINUOUSLY TIN PLATING FERROUS METAL STOCK John S. Nachtman, Beaver, Pa.

Application March 30, 1937, Serial No. 133,911

5 Claims.

This invention relates to process and apparatus for producing metal stock coated with dissimilar metal, and particularly to process and apparatus for continuously coating sheet and the like ferrous metal stock with tin whereby sheets, strips and the like of indefinite length may be produced continuously in finished marketable form.

The invention is designed, primarily, to produce tin-plated ferrous metal stock or strip. Reference may be made to my copending applications Serial Nos. 126,529 and 127,776, filed February 18, 1937, and February 25, 1937, respectively.

The method of tin-plating ferrous metal stock for the practice of which the apparatus of the invention is particularly designed, includes the following steps, viz.: providing a continuous supply of stock by attaching, preferably by welding,

the end of a fresh strip to the end of an exhausted strip, adjusting the feed of the strip in such a manner, preferably by means of a looping slack-producer, that continuous passage of the strip through subsequent stages of treatment in the apparatus may be continued during the period when the end of an exhausting strip is held stationary for welding to it the end of a fresh strip, cleaning the stock by passingit through appropriate cleaning and degreasifying baths of electrolytic or other appropriate forms, scrubbing the stock by means of appropriate brushing mechanism, rinsing and pickling the stock with subsequent scrubbing, electroplating the stock with subsequent scrubbing, rinsing and drying the stock, alloying, cleaning and bumi shing the stock, and finally coiling or otherwise appropriately preparing it for removal and handling. In the apparatus as illustrated in the drawings, and as hereinafter more particularly described, the cleaning of the stock, before its subjection to the plating operation, is accomplished in tanks in which electrolytic cleaning is not resorted to. However, electrolytic cleaning may be resorted to as a substitute or supplement.

Furthermore, the alloying and burmshmg operations as hereinafter disclosed are conducted with greater facility, and in a more economical manner than has heretofore been possible, at the same time furnishing a product superior in quality and uniformity, and the various elements or units of the apparatus, whereby the steps of the plating methodare accomplished, are designed, arranged and coordinated to most effectively attain these objects, so that the sequential steps of the method maybe performed cbntinuously, and the product continuously discharged, as distinguished from apparatus of similar types wherein the stock must be repeatedly handled for transfer from apparatus for performing certain method steps upon it to other apparatus for performing subsequent steps of the method.

In other words, when the metal stock is continuously fed into the apparatus of the invention, its passage therethrough for subjection to and treatment in accordance with the various method steps may be uninterrupted, while at the same time subject to inspection as desired, and

by means of baths 'of hot and cold oil, but an furnace of the reducing atmosphere gyp g d its adjuncts, may be employed for this purpose.

The apparatus of the invention is designed, as hereinbefore indicated, for continuous operation, whereby, as a specific example, tin-coated ferrous metal strip, preferably steel strip, wire or sheet,

' 'may be produced by an electroplating process the product may be continuously discharged.

The invention comprises apparatus for continuously coating (preferably electroplating) metal stock in strips, wire or sheets of indefinite length, including, in combination, means for supporting metal stock to be fed into the apparatus, means for joining the end of one piece of stock to another to produce a continuous strip, means providing for the stopping of the end of the strip during the joining operation, while the balance of the strip continuesto move through the apparatus, means for cleaning, pickling, scrubbing, rinsing, plating, drying, alloying and burnishing the stock, and finally cleaning, rinsing, drying and discharging the finished plated product, means for properly guiding and tensioning the strip during its travel, and in various novel features inherent in the means referred to, all as will be pointed out more particularly hereinafter and finally claimed.

In the accompanying 'drawings illustrating the invention, in the several figures of which like parts are similarly designated,

Figures 1a, 1b and 10, when placed end to end in order, illustrate, send-diagrammatically, a preferred embodiment of the complete apparatus of the invention.

Fig. 2 is an enlarged side elevation of the payout end of the machine, including the pay-out blocks, feed table, welding mechanism, squeegee and clamp of the invention.

Fig.3 isa plan view of some of the parts 11-- lustrated in Fig. 2.

Fig. 4 is an enlarged side elevation of the slack-producer and its associated clamp.

Fig. 5 is an enlarged side elevation of a scrubbing unit, bridle-stand. a fragment of an electroplating tank, and an interposed dancer roll.

Fig. 6 is an enlarged fragmentary side elevation of an electroplating apparatus of preferred form, as shown in Fig. 1b, and particularly adapted to the plating of relatively light (thin) stock.

Figs. 7a, 7b and 7c illustrate, on a large scale, the two end portions and a part of theintermediate portion of an electroplating tank of a type particularly adapted for the plating of relatively heavy (thick) stock, Fig. 70 showing the provision of a squeegee for the stock as it leaves the tank. 1

Fig. 8 is an enlarged fragmentary sectional elevation illustrating the hot oil tank, the cold oil tank, and the power-drivensqueegees and roll associated therewith.

Fig. 9 illustrates a modification of the arrangement of the hotoil tank and the cold oil tank. a Fig. 10 illustrates a further modification of burnishing apparatus, including a cold air blast means in place ofthe cold oil tank, associated with a hot oil tank, and

Fig. 11 illustrates polishing mechanism similar to the scrubbing mechanism of Fig. 5, but appropriately modified.

The pay-out device A of the machine includes a foundation member, bed or base I provided with bearings 2 and 2 in which are rotatably mounted similar shafts 3 and 3 respectively, provided with overhanging extensions 4 and 4' of expansible type upon which may be mounted reels 5 carrying the coiled strips of stock S to be subjected to the electroplating process. "These reels are clamped upon the extensions 4 and 4' by virtue of their expansible nature and may be locked in place thereon, if desired, by plates 6 and 6'. Hence, as the stock is withdrawn from the reels, and the reels thereby rotated, the shafts 3 and 3' will turn with them. In order that rotation of the reels may be retarded so that proper tension may be maintained upon the unwinding stock, the

shafts 3 and 3' are provided with brake drums I and 'l', with which cooperate brake shoes 8 and 8' carried by arms 9 and 9' to which are applied adjustable weights l0 and I0, respectively.

It will be obvious that one of the reels 5, and the stock carried thereby, may be held in reserve while stock is unwound from the other reel, and that when stock is exhausted from such other reel, and the end of such stock leaves the reel, the stock on the first-mentioned or reserve reel may be fed into the apparatus and joined to the end of the stock just exhausted, as will be explained in detail hereinafter.

Each of the reel-carrying extensions 4, 4', has located adjacent to it a guide roller Ii carried on a shaft l2 mounted in brackets l3 arranged upon the bed or base i, and these rollers II are thus so arranged that the stock may pass over them as it leaves the reels 5, and be supported by them and guided to a hold-down roller I4 arranged adjacent to a table I 5 providing a support upon which the stock may readily be handled, and furnished with a guide or fence l6 by means of which proper alignment of the stoc may be insured.

At the opposite end of the table I5 is arranged the welding apparatus B comprising a supporting block l1 and a welding head I8, and these parts are supported upona stand l9, and are so designed as to produce, transversely of the overlapped ends of the pieces of stock a plurality of spot welds whereby such ends may be Joined to 1 provide an unbroken strip of stock for passage through the succeeding elements or units of the apparatus.

In order that, subsequent to the welding operation, the strip of stock may be aligned and tensioned, a pressure device or squeegee C is provided including a fixed roller 20 and a movable roller 2!, both of which are preferably made of rubber. and the latter of which is carried by a frame 22 slidable on supports 23 and subject'to pressure exerted by springs the compression of which may, as desired, be regulated by adjustable stops 2!.

As will appear from the previous discussion, the stock or strip is preferably handled in such a manner that it is at all times substantially continuously and uninterruptedly moved past the various treating positions. That is, in accordance with my invention, the movement of the strip along the electroplating line will be carried out as before even while the trailing end of one coil or strip is being welded to the leading end of a new strip coil. To this end the slack-producer D is provided (see particularly Fig. 4). This slack-producer operates in conjunction with an appropriate clamp E preferably comprising clamping blocks 28 and 21 responsive in operation to the energizing and de-energizing of a solenoid controlled by the operator during the welding operation, and functioning to immovably clamp the exhausting end of a strip of stock while the operation of welding the end of a reserve strip thereto is being performed.

As shown, the slack-producer D comprises a as to accommodate loops of stock aggregating over feet in length, and it includes three stationariiy mounted rollers 29, 30 and 3! and two movably mounted rollers 32 and 33 over which the strip of stock is passed back and forth, as shown, to produce the desired extended loops. The rollers 32 and 33 are mounted in an elevator carriage 34 travelling in vertical guides 35 and connected by a cable 36 with hoisting mechanism including a motor and gearing 31 and a brake 38. Obviously, when the elevator carriage 34 is at the top of its shaft the loops in the strip of stock will be extended to the limit, and therefore the greatest amount of slack will be produced in the strip. Now, when the strip is clamped by the clamp E at one end, and the body of the strip is still travelling throughout the apparatus, the elevator "carriage 34 will descend to permit such travel, and the slack originally produced is such that before the carriage 34 reaches the lower limit of its travel the welding operation referred to will have been completed. Upon the completion of the welding operation and the release of the clamp E, the elevator carriage will again be hoisted to the upper limit of its movement, and additional slack will be produced in the strip of stock in preparation for a subsequent welding operation. Of course, the framework 28 will be built of a height suilicient to accommodate any extent of slack to d necessary.

As the strip of took S leaves the slack-producer, it is engaged by the rollers of a squeegee C substantially similar in construction and function to the squeegee C, and the stock passes thence into a cleaning tank F in which it is cleansed, degreasified and partially prepared for plating. In the embodiment shown, the cleaning tank F is a bridle stand J (see Fig. including feed rolls such that cleaning by the use of an ordinary solution, by saponification, emulsiflcation or the like, may be resorted'to, and it is preferably a steel tank lined with rubber. However, see my copending application No. 127,776, electrolytic cleaning may be-resorted to at this stage, and in such case an electrolytic cleaner of any desired type may be employed, the electrolyte being such as will satisfy the cleaning requirements without unduly attacking the stock.

The cleaning tank F is preferably provided with rollers 39 which hold the stock submerged in the cleaning fluid, and with a roller 46 arranged.

which obnoxious vapors and fumes may be removed, and the inspection doors are provided at suitable intervals in the hood, one of same being located adjacent to the elevated roller 40.

Upon passing from the cleaning tank F, the strip S is operated upon by a scrubbing-mechanism G (see particularly Fig. 1a, and compare Figs. 1b and 5) including reciprocating rotary brushes 44 and 44' arranged for contact with the opposite faces of the strip S, and rubber or other suitable rollers 45 and 45' arranged toback up the strip in alignment with the brushes 4 and 44'. Appropriate pressure may be applied to the brushes 44, 44' by any appropriate means (not shown) controlled by the handrwheels 46, 45'. As shown in the drawings (see Figs. 1a, 1b and 5) of the scrubbing mechanisms G, G and G, the strip S in moving across the back up rollers 45 and 45 passes in slightly arcuate paths so that first one convex arcuate surface on one side and then another convex arcuate surface on the other side of the strip is brushed by the brushes l4 and H, The reciprocation and rotation of the brushes may be imparted to them by any suitable means (not shown) power-driven by a suitable motor ll. Included in combination with the scrubbing mechanism G is a squeegee 48 somewhat similar in construction to the squeegees C and C However, as previously described, squeegees C and C work on dry strip and provide a tension on the strip, while the squeegees 48 work on wet strip and thus prevent carrying over of the cleaning solution. Water is sprayed upon both sides of the strip S as it passes through the scrubbing mechanism, by any appropriate spray device or the like, not shown.

Upon leaving the scrubbing mechanism G, the strip of stock passes into a rinse tank H wherein it is held beneath the surface of the rinse water by a roller 49. Fresh water is constantly fed to this rinse tank and it may, if desired, be heated by a steam coil or other appropriate means. Moreover, a spray of water is preferably directed upon the strip, as it emerges from the tank H and passes therefrom over the roller 50 into the pickle tank I. This pickle tank is provided with rollers 5| which hold the strip submerged in a pickling liquid of a character and strength suitable to the final stage of preparation of the strip for the electroplating operation. The rinse tank H and pickle tank I are preferably covered by a hood 52 having substantially the same character and function as the hood previously described.

Opon leaving the pickle tank I, the strip of stock is subjected to another scrubbing operation by a scrubbing mechanism G similar to the scrubbing mechanism G, and it passes thence to 53 and 5| geared together as indicated at 55 and a pressure roll 56 to which appropriate pressure is applied by springs 51 the compression of which may be regulated by a suitable screw 58. Chain and sprocket gearing 59, 60, 6| supplies a power drive from the motor 62 and gear box 63 to the shaft 65 of the roller 53, and thence through the gearing 55 to the roll 54. The pressure roll 56 furnishes friction between the roll 54 and the strip S adequate for feeding of the strip under the influence of the drive described. This bridle stand is shown as furnishing the initial feed of the strip S through the preceding units of the apparatus, but if desired the squeegees C and C and any of the rolls in the tanks F, H and I and in the scrubbing mechanisms G and G may be power operated to additionally drive the strip. If the squeegees C and C are power operated, their motors will act as previously explained to provide tension on the strip.

As the strip S leaves the bridle stand J it passes over a guide roller 65 and thence to a weighted dancer roll 66 operating in a well or guideway 61 and functioning to maintain a proper tension upon the strip after it leaves the bridle stand.

The strip next passes into the electroplating tank. This electroplating tank may take a variety of forms, but those best suited to the apparatus as a whole are illustrated particularly in Figs, 1b and 6 and in Figs. 7a, 7b, 7c, respectively.

It is to be noted that the provision of the bridle stand J and dancer roll 56 just prior to the point of entrance of the strip S into the electroplating tank makes it possible for the strip to enter the tank under no appreciable tension, and that this lack of tension maintains throughout the passage of the strip through the tank, thus guarding against the occurrence of wavy edges in the strip and the necessity for finally rolling the strip to restore it to its original desired flat form.

The electroplating tank K of Figs. 1b and 6 is best suited to the handling of relatively light (thin) stock, whereas the electroplating tank of Figs. 7a, 7b, 7c is best suited to handle relatively heavy (thick) stock. When the stock is light it may easily be looped as illustrated in Figs'. lb

and 6, but when it is relatively heavy it does not lend itself so readily to this looping, being more easily and effectively handled by substantially continuous horizontal passage. Obviously, the

type of electroplating tank illustrated in Figs.

rollers 69, some of which latter may be power-- driven, if desired, at a speed in sychronism with the predetermined speed of travel of the stock S,' and the stock is looped upon these rollers, as

shown, and thus subjected to electrolytic action in the tank. A plurality of anodes l0 vertically suspended within thetank by a bus bar (not shown) are connected withthe positive side of a source of current, preferably one or more motor generator sets, and the strip of stock S becomes the cathode by virtue of connection of an appropriate number of the rollers 69 with the negacontrolled by means of electrically energised heatingrodssuch as'low diifusicnOalrodslLand asanaidtomaintainingdesiredtemperatureof the oil, the tankmay be providedwith asectional In the type of electroplating tank illustrated in Figs. 7a, 7b, 7c, the anodes II are supported horizontally upon suitable hangers '(not shown) and the strip of stock 8 passeshorizontally between them and beneath guide rollers II between which latter it is, at appropriate intervals, looped upwardly for passage over conductor rollers 14. The anodes I2 and the conductor rollers I4 are connected, respectively, with the positive and negative sides of the source of current in substantially the same manner as in the form of electroplating tank illustrated in Figs. 1b and 6,

appropriate brush and commutator means II being provided for the contact rollers 14.

In both forms of electroplating tanks illustrated, the number of contact rollers 69 and 14 which may be connected to the source of current is dependent upon the ampere capacity of such source and the characteristicsiof the coating or plating desired. I

As indicated, the strip of stock is subjected to the action of a squeegee C as it leaves the eleccover composed of slabs or plates 02.

Issuing from the hot oil tank through a narrow slot or shield member 1,108 Figs. 1b, 1c, 8, and 9, that prevents transfer. of the oil, the plated stock enters a cold oil tank qin which it is subjected to the cooling and brightening action'of cold oil circulatedin the tank by means of a circulation pump (not shown) having its intake connection at It and its discharge con-- nection at II, II, in a member or non-ls ll enclosing a portionof the strip and the oil against both sides thereof. Since, as shown, the lower part of the entrance side (hot oil side) of the member 88 has a higher elevation than an upper part of the member on its discharge side (cold oil side), a static balance is obtained between the hot and cold oil chambers; also, eddy currents such as due to a thermo-siphon action between the hot and cold oil are prevented. The hot oil tank and the cold oil tank are surmounted by a hood I! similar to the hoods previously referred to.

, troplating tank, whether the tank be of the form illustrated in Figs. lb and 6, or that illustrated in Figs. 7a, 7b and 7c, and excess of electrolyte thereby removed.

The plated or coated stock is now subjected to the action of a scrubbing machine (3 similar to the scrubbing mechanisms G and G and passes thence into a rinse tank L, provided with a hood I6 and a squeegee C and then to a hot air drier M.

The hot air drier M, in the form shown, comprises merely a housing 71 with a hot air intake 78 supplied by any appropriate means not shown, and furnished with a fan is. It will be understood that this type of hot air drier is merely illustrative, and that the plated stock may be electrically or otherwise heated to dry it, if desired. The function of this hot air drying is to preheat and completely dry the plated stock.

After leaving the drier M, the plated stock is subjected to the tensiohing action of a dancer roll 00, to some extent similar to that previously described, and passes thence through a hot oil tank N in which the oil is maintained at a temtemplated by the invention of my application Serial No. 127,776, hereinbefore referred to, the tin plating is deposited upon a preliminary plating of copper, nickel, chromium or other appropriate metal or alloy, then the action of the hot oil bath will be to melt and alloy the outer coating of tin with the under coating of dissimilar metal to produce an impervious and brilliant finish.

As illustrated particularly in Fig. 8, the oil is heated and its temperature thermostatically Instead of forming the hot and cold oil tanks N and 0, respectively, as two separate units connected by a slot member II, they may be formed as a unitary structure divided into two compartments N and 0', see Figure 9, for the hot and cold oil, respectively, by. a heat-insulating partition 83' suitably sheathed as indicated at 83". Inasmuch as the cold oil is constantly circulated, and thus cooled, by way of the intake 84 and discharge means 8 l, the temperature will be maintained between and I". and the flow of the oil will thus govern the temperature in the casing of the apparatus.

It will be noted that the construction of the hot and cold oil tanks, whether of the form illustrated in Fig. 8 or in Fig. 9, is such that very little transfer of oil from one tank to the other can take place, the principle of the apparatus being that of a'U-tube, whereby the specific gravity of the oil in one tank holds the oil in the other tank in balance.

In place of the oil, a salt solution may be used in the hot bath.

In passing from the cold oil'tank O, the plated, annealed and burnished stock is subjected to the action of a roller 88 and squeegees C and 0, all of which are power driven, preferably by chain and sprocket gearing, as shown, from a motor 88 and a gear box 00. The power driven roll 88 and squeegees C and C serve not only to remove from the plated stock surplus oil adhering to it,

and which might otherwise 'be carried out of the oil tank 0, but to maintain considerable tension upon the strip as it passes through the oil tanks, and to drive it on its way to the other units of the apparatus.

As illustrated in Fig. 10, the cold oil tank may be dispensed with. and as. a substitute therefor blast or jet means T may be provided whereby cold dry air may be projected against both sides of the strip.

Instead of employing the oil baths just described at this stage of the process, the alloying and brightening of the strip may be accomplished by means of a reducing atmosphere furnace, thus dispensing with the cleaning apparatus, hereinafter referred to, made necessary by the employment of the hot and cold oil tanks.

When a furnace is employed for the purpose of alloying the coating, it may be supplemented by water spray devices operating upon the strip as it emerges from the furnace, and the strip may thereafter be burnished by a machine including rotating and reciprocating bumishing rolls furnished with surfaces composed of steel wool, glass wool, brass wool, or other appropriate similar substances.

Also, if desired, the spray means may be omitted and the plated strip burnished hot, as it comes from the furnace, by the burnishing rolls.

The burnishing machine may be constructed in a manner similar to the scrubbing mechanisms G, G G hereinbefore referred to, substantially as illustrated in .Fig. 11, wherein the rotating and reciprocating rolls 44 and 44' are shown as provided with metallic wool facings .44".

When the oil treatment is not resorted to, and the furnace, sprays and burnisher used instead, the subsequent cleaning and drying apparatus P, P Q, L L and M hereinafter specifically referred to, may be omitted, and the finished stock, as it comes from the burnishing machine of Fig. 11 led to the bridle stand J and wind-up R.

However, the oil treatment of the plated stock is included in the preferred embodiment of the apparatus herein disclosed as it produces a most lustrous finish and is considered most desirable for the continuous operation intended.

Moreover, if desired, after the strip of stock has been plated, scrubbed and rinsed, a wind-up may be employed, and 9. terminus established at this point in the process for which the apparatus is intended. Thereafter brightening and alloying of the plated strip may be accomplished by either the oil treatment or furnace treatment as a separate operation. Inasmuch, however, as the apparatus herein disclosed is designed for the purpose of treating the stock in such a manner as to continuously produce, from the original strip, a completed product subjected in the apparatus to the various steps of an appropriate electroplating process, without interruption, the complete apparatus either in the form illustrated, or with such modifications as those referred to for making possible the inclusion of additional steps in the process, is deemed to be the most satisfactory and efficient embodiment of the invention.

From the squeegees C and C the strip S passes through a cleaning tank P, squeegee C and rinse'tank P, which tanks are similar in function and operation to the tanks F and H, respectively, hereinbefore described, to an electrolytic cleaning tank Q. In .rthis electrolytic cleaning tank, the strip S is supported and guided in its passage by metal rolls 9|, which give it a charge of electricity and conduct it between oppositely.

charged iron grids 92. The electrolyte may be of any appropriate character which will not, under the influence of electric current, injure the coating or plating of the strip, but will function merely to remove from it any grease, oil and fatty substances carried over by it. The electrolyte may be continuously circulated in the tank Q by any appropriate means, not shown.

After leaving the electrolytic cleaning tank Q, the strip passes through a squeegee C to rinse tanks L and L similar in function and operation to the rinse tank L, and thence through a squeegee C, a hot airdrier M or its equivalent, as explained in connection with the hot drier M, whence it is led to a bridle stand J 1 similar to the bridle stand J but driven, in combination with a windup mechanism R by an electric motor 93 and appropriate gearing. The tanks P, P Q, L and IF are provided with hoods 94, 95 and 96,'respectively, similar to those previously described, for collecting and carrying off vapors and fumes.

The wind-up mechanism includes guide rollers I 91 and 98 which may be ,used for guiding the finished strip to reels 99 and!!! respectively, whereby as one reel is filled with the finished strip, the strip may be severed and its severed end led to the other reel to continue the winding, thus providing for removal and replacement of the filled reel. The reels of the wind-up mechanism are preferably similar to those of the payout A, and interchangeable therewith, the shafts upon which the reels of the wind-up mechanism are mounted being substantially similar in construction and mode of operation to the shafts 3', 4' of the pay-out A but equipped with friction clutches operated by the motor drive to compensate for gradually increasing size of the wound strip; the drive, generally, being synchronized with the travel of the strip through the apparatus.

Obviously if, as hereinbefore indicated, it is desired to deposit upon the strip a preliminary coating or plating of a metal or alloy prior to plating with tin the electroplating tank by which such preliminary coating or plating is deposited, should be followed in the apparatus by appropriate scrubbing and rinsing means.

Furthermore, should it be desired to dispense with alloying and brightening of the coated or plated strip, the terminus or wind-up of the apparatus would follow the scrubbing, rinsing and drying apparatus which operate upon the strip subsequent to its passage through the electroplating means. Although for the purpose of simas sheets, etc.; the base metal shape'or strip preferably has some characteristics of flexibility. Various changes and modifications, other than and in addition to those specifically referred to,

are considered to be within the spirit of the invention and the scope of the following claims.

I claim:

1. In a method of making a bright tin electroplated continuous metal strip, the steps of wet mechanically cleaning the surfaces of a continuously moving tensioned strip by passing the strip in slightly arcuate paths, brushing under pressure first one convex arcuate surface on one side and then another convex arcuate surface on the other side of the continuously moving tensioned strip, maintaining said arcuate surfaces by backing up the strip against the brushing elements, and spraying the strip while brushing; then immediately passing the strip into an electrolyte and electroplating the continuously moving strip with tin, then removing electrolyte from the continuously moving electroplated strip surfaces, and brightening the continuously moving electroplated surfaces by subjecting the same to a medium maintained at a temperature sufiicient to alloy the tin with the strip; continuously moving and tensioning the strip during said mechanical cleaning, electroplating, electrolyte removing, and brightening steps by applying direct propulsive power to said strip at a plurality of steps; the applying of 'said propulsive power serving to control the tension on the continuously moving strip during each of said steps.

2. The method as defined in claim 1 in which a reduced tension is maintained on the strip as it passes through the electroplating step..

3. The method as defined in claim l-in which the treatment following the electroplating step includes wet mechanically brushing the surfaces of the continuously moving electroplated strip by passing the strip under tension in slightly arcuate paths, brushing under pressure first one convex arcuate surface on one side and then another convex arcuate surface on the other side of the continuously moving tensioned strip, maintaining said arcuate surfaces by backing up the strip against the brushing elements, and spraying the strip while brushing.

4. The method as-deflned in claim 1 in which the brightening treatment following the electroplating step includes immersing the continuously moving tensioned strip in a hot oil bath for heating the electroplated material to a temperature sumcient to melt the same and alloy it with the strip metal body. and then immediately cooling the heated electroplated continuously moving tensioned strip to provide brightened electroplated surfaces. v

5. The method as defined in claim 1 inwhieh the brightening treatment following the electroplating step includes heating the electroplated material in a reducing atmosphere furnace to a temperature sumcient to alloy it with the strip metal body and then passing the strip under tension while hot in slightly arcuate paths, bumishing under pressure first one convex arcuate surface on one side and then another convex arcuate surface on the other side of the continuously moving tensioned strip, and maintaining said arcuate surfaces by backing up the strip against the burnishing elements.

JOHN S. NACH'IMAN.

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