US2342850A - Apparatus for electroplating metal strip - Google Patents

Description

3 Shee ts-Sh eet '1 INVENTOR Jhn F/rm HMJ RNEYS J. F. FERM APPARATUS FOR ELECTROPLATING METAL STRIP Filed Jan. 30 1941 Feb. 29, 1944.

Feb. 29, '1944.

J. F. FERM APPARATUS FOR 'ELECTROPLATING METAL STRIP File d Jan. 50, 1941 s Sheets-Sheet 2 v Jbm wem' BY I M t ATTORNEYS Feb. 29, 1944.

J. F. FERM APPARATUS FOR ELECTROPLATING METAL STRIR Filed Jan. 30 1941 3 Sheets-Sheet 3 i- ORNEYS WW5 aw INVENTOR John F Frm' Patented Feb. 29, 1944 John F. Ferm, Midland, Pa, assignor to Crucible Steel Company of America, New York, N. Y..- a corporation of New Jersey Application January 30, 1941, Serial N 376,658

8 Claims.

This invention pertains to improvements in electroplating apparatus, and more especially such as is adapted to the plating of continuous metal strip, by .the use of pinch rolls interpolated between successive plating zones, and which are so coordinated with pinch rolls located beyond the plating zones that non-uniform and excessive tension on the strip, and slippage of the strip with respect to the feed rolls, while passing through the plating zones, are eliminated.

' .As regards the feeding of the strip through the plating bath, one practice has heretofore been to, pull. the strip over idler rolls disposed throughout the bath, by means of power driven pine or bridle rolls positioned on the exit side of the bath. This is unsatisfactory owing to the progressively increasing tension, produc-g tive of breakage, exerted on the strip as it passes through the bath. In long plating lines this tension on the strip may increase in the ratio of as much as 7 or 8 to 1 from the input to the output end. Alternatively it has been proposed to apply a positive drive to feed rolls distributed along the bath, which, however, is productive of slippage of the rolls against the strip, due to slight irregularities in roll driving speeds, tension in the strip, etc., whereby the surface of the strip is scratched and marred. I

In accordance with this invention, it is proposed to eliminate this objectionable arrangement by employing in conjunction with the power driven pinch rolls on the exit side of the bath, other power driven pinch rolls positioned at intervals along the bath, thes latter rolls, however, being individually connected to a source of driving power through over-drive, slip clutches, preferably so adjusted that the tension exerted on the strip by the exit pinch rolls very slightly under-drives the positively driven parts which drive the clutch driven pinch r6115, the ideal adjustment being that at which the strip drives these rolls at exactly-the same speed at which they are driven through their associated slip clutches. With" this arrangement the strip merely floats on the clutch driven rolls, with no slippage and subject to uniformly low tension.

Referring now to the drawings:

Fig. 1 is a plan view, in more or less schematic form, of a plating bath in accordance with the invention for plating continuous strip, the bath consisting, in this instance, of seven plating sections.

Fig. 2 is an enlarged plan view, corresponding to portions of Fig. 1, but showing one of the plating sections considerably more in detail.

Fig. 3 is a longitudinal section taken at H of Fig. 2.

Fig. 4 is an enlarged view in side elevation of one of the plating sections as viewed from below in Fig.. 2.

Fig. 5 is a transverse section in elevation taken at 5-5 of Fig. 2, this view illustrating the relative arrangement of the contact roll assembly and the manner in which these rolls are driven through the overdrive, friction clutches above referred to.

Fig. 6 is a sectional detail, taken at 6-6 of Fig. 2, and illustrating the manner in which the plating racks are supported and connected tothe electrical bus bars.

Fig. 7 is a view taken substantially at 1 1 of I Fig. 5, partially schematic and partially in section, to illustrate the mode of adjusting the pressure between rolls of the contact roll assembly. Fig. 8 is an enlarged plan view of one of the contact roll assemblies illustrating the manner in which the contact shoes are connected to the bus bars. a

Fig. 9 is a perspective view of one of the contact shoes in accordance with the invention.

Fig. 10 is an enlarged sectional view, taken at ill-l0 of Fig. 2, and illustrating the construction of the overdrive, frictional clutch construction for driving the" contact rolls.

Fig. 11 is a section at l|-l| of Fig. 10.

Referring to the several figures of the drawings in which like elements are similarly designated,

the apparatus comprises an elongated sheet metal plating tank I, mounted on supports 2, and filled to about the level 3 with plating solution. The metal strip 4 to be plated, is fed repeatedly into and out of the bath by means of the contact roll assemblies 5 positioned above the bath, and the pairs of idler rolls 6, I immersed therein, the strip passing into the bath between the rubber or like covered lower roll 8 and the upper metal roll 9 of a contact roll assembly 5, thence under an idler roll 6 beneath the surface of the plating solution, and thence between a series of upper and lower plating racks III, II, on which are placed bars, such as l2, I3,

of the material to be plated, thence under an idler roll 1, and out of the bath between the rolls 8, 9 of the next succeeding contact roll assembly, whereby the bath is divided into a numher of plating sections for progressively plating strip. The entire plating bath comprises, as shown in Fig. 1, seven such plating sections ll, the contact roll assemblies 5, for all of which, are driven by a common motor 15 through a 2 shaft l8, extending the lengthof the bath, and in a manner explained more in detail hereinafter.

Referring more particularly to Figs. 3, 5 and 7, each of the contact roll assemblies 5 comprises, as stated, a lower roll 8 covered with an electrical insulating material, such as rubber, rubber composition, etc., and an upper roll 8, which is entirely of metal; Rolls 8, 8 are Journaled into bearings, such 7 as l1, l8, Fig. 7, respectively, which are so supported as to be vertically ad- Jus'table with respect to each other, for varying as desired the pressures between the rolls. To this end, bearings l1 are bolted, as shown, to frame members |8,'which in turn are bolted to, and carried by, the supports 2 for the plating tank I. The bearings l8 are in turn bolted, as shown, te-open frame members 28, which in turn are vertically adjustable in guides 2|, secured- Each of the frames 28 is centrally supported atthe top, by a bolt 22, which passes at its lower end through an apertured plate 28, formin: part of the frame 28, this bolt being provided with a flanged lower end for purposes of such support. At their upper ends, the bolts 22 pass through an apertured cross member 24, forming part of the frame l8, and are threaded thence through gear members 28 rotatable by worms 28, keyed to a shaft 21, whereby frame 28 may be raised and lowered by rotation of the shaft.

exert resilient pressure on roll 8, a washer 28 is pin-connected, .as shown in Fig. '7, to each bolt 22, and between this washer and the associated plate 28 of frame 28, is interposed a helical spring 28, whereby sufllcient downward adjust- Fig. 2. Keyed to spindle 85 is'sprocket 81, which drives through chain 88, a sprocket 88 keyed to gages the ring member 55, under the pressure of springs 58. The ring members 55 and 85a may be slidably keyed as indicated to sleeve 5|; Sleeve 5| is journaled on an inner sleeve 51, this inner sleeve having a flanged inner end 58 abutting the inner end of sleeve II, and having secured to its outer end" a retaining washer 58 engaging a recessfin sleeve 5|, as shown, for securing the two sleeves 5l, 81 together. The shaft 48, for roll 8, is keyed as indicated in sleeve 51, and sleeve 51' has keyed in its outer end a member 88, containing a diametrical slot,

inwhich are slidably mounted a pair of driving pawls 8|, 82, spaced resiliently apart by an interposed helical spring 88. The pawls 8|, 82 engage the teeth of a ratchet ring 84, which is 'keyed to sleeve 5| as-shown. The pawls 8|, 82

are held in place by a cover plate 84a, bolted to the outer endof sleeve 5|. 4

In the operation of this clutch, the motor l5 applies a positive drive to the clutch sprocket 48, through the sequence above described and in a direction of rotation corresponding to that in which the roll 8 is driven by tension exerted on the strip 4, by the positively driven pinch rolls, indicated at 85, Figs. 2 and 3, through which the strip passes on leaving the plating bath, these '80 For causing roll 8, when lowered sufllciently, to

pinch rolls being positively driven by a separate motor 88, through a warmer bevel gear, indicated at 81. Sprocket 48, in turn, applies a positive drive to bushing 41a bolted thereto, and in turn to collars 48a, 48, which apply a frictional drive to sleeve 5|, the slippage of which is determined by the axial pressure exerted on'the collar 48 by the helical springs 58, which pressure is adjusted, as desired, by manipulation of the handwheel 54, rotation of which increases or decreases the spring pressure, by axial movement of the bushing 53. The frictional drive applied to sleeve 5|, is in turn transmitted as a positive drive to the roll shaft 48, due to engagement of the radial edges of the teeth of the ratchet ring 84, secured to sleeve 5|, with the driving pawls 8|, 82, se-

cured to shaft 48, through pawl holder 80, keyed shaft l8. At eachof the contact roll assemblies 5, the shaft l8 has keyed thereto a bevelled gear 48 meshing with a cooperating gear 4| keyed to a spindle 42, journaled through bearings 48, carried by the frame supports 2. Also keyed to spindle 42, is a sprocket 44, which drives through chain 48, a sprocket 48, forming part of an overdrive, friction clutch 41 mounted on shaft 48 of roll 8, whereby roll 8 is driven from sprocket '44 through the friction clutch 41.

The construction of the overdrive, friction clutch is shown more particularly in Figs. 10, 11, referring'to which, the sprocket 48 is bolted, as

shown to a bushing 41:: formed of insulating material such as a suitable laminated phenolic product, disposed between and shaped to interengage in keyed relationship, a pair of peripherally flanged metal collars48a, 48, which are spaced apart as indicated at 58, and which are joumaled on a sleeve member 5|, having a flanged inner end 52, against which the inner collar 48a frictionally engages. The sleeve mem-' ber 8| has threaded onto its outer end. a bushing 58, forming part of a handwheel 54. Interposed between the outer collar 48 and the bushing i 53, are ring members 55, 55a, containing peripherally spaced recesses, for reception of a series :ofhelical springs 58 positioned between these ring members. The collar 48 frictionally ento sleeve 51, which in turn is keyed to shaft 48. The clutch sprocket 48 thus applies a frictional drive to the contact roll shaft 48, the torque of which is determined by the adjustment of the handwheel 54. Adjustment of the handwheel should be so thatthe driving force on roll 8 will notbe so great as to produce slack in the strip between contact roll assemblies. The drive thus applied to shaft 48 of roll 8 is also applied to theshaft of roll 8 by virtue of the intermeshing gears 88,v 88', keyed to these shafts respectively. The amountof slippage is determined by the variation in the speed of the clutch drive over the speed of the main pinch roll drive.

Now, as explained above, the strip upon leaving the plating bath, is fed between'the power-driven pinch rolls 85, Fig. 2, which apply a positive drive to the strip and thus pull the strip through the plating bath contact roll assemblages, at a surface speed determined by the speed of rotation of the power-driven pinch' rollg.85. The clutch drive motor speed is adjusted so as to slightly overdrive the sprockets 45 of clutches 41. Therefore, in normal operation, the contact roll shaft will be driven by the strip than the clutch sprocket 45, 6|,62 will move around in the by the inner arrow of Fig. 11 with respect tothe ratchet ring 64, this being accomplishedbythe sloping edges of the ratchet ring teeth forcing the pawls 6|, restraining action of the interposed helical spring 63. v

Ideallsnthe positive feed applied to the strip by the exit pinch rolls .65, in turn drives the con-' tact rolls '8; 9 at exactly the same speed as these rolls tend to be driven through the friction clutch, whereby thestrip, in effect, merely "floats on the contact rolls as it passes through the plating bath, in consequence of which the tension exerted on the strip by the exit pinch rolls remains substantially constant throughout the plating bath. This operation prevents the building up of too great a tension in the strip, such at a greater speed whereby the pawls 62 inwardly against the resilient direction indicated I as would cause breakage, and such as would I occur if the entire drive were due to pull exerted on the strip-by the exit pinch rolls. Also by virtue of this operation, the strip is prevented from dragging across the faces of the rolls, thereby to avoid scratching and the surfaces of the plated strip. In certain of the claims a first mentioned pair of pinch rolls is referred to as being located in advance of a second mentioned pair of such rolls. By this is meant that the strip material passes through the first mentioned pair of pinch rolls before reaching the second mentioned pair of pinch rolls.

Considering now the electrical aspects of the contact marring apparatus, Fig. 3 indicates diagrammatically the circuits for'applying current to the plating bath. A direct current generator 10 has its negative terminal connected in parallel over conductors such as H, 12, to contact shoes 13, which bear against the contact rolls 9, the positive generator terminal being connected in paralle1 over other conductors, such as 14, 15, to the plating racks l0, II. Employing the conventional direction of current flow, i. e., from the positive to the negative generator terminal, the current flow is from the positive generator terminal to the plating racks H], H, and to the bars of pure plating material l2, l3, such as bars of tin supported there- I by, thence through the plating solution to the material through successive plating zones,

metal strip 4, thence along the strip tothe contact rolls 9, and thence to the contact shoes-13, returning to the negative generator terminal.

As regards the electrical aspects of the apparatus as actually constructed, Figs. 2, 3, 5 and 6,

show these details with respect 'to the plating rack assembly, while Figs. 3, 8 and 9 give the same information with'respect to the contact roll assembly. The plating racks consist of a succession of U -shaped members to, II, dipping into the plating bath, and supported at their upper. ends, on insulating blocks, such as 16, 16a, Fig. 6, composed of rubber or other suitable insulating material, these blocks being carried by the frame members 2. Also as shown in Fig. 6, bus bars I1, 18, comprising piles of copper strips, are interposed respectively between the plating racks I0, H and the insulating support 16. As shown in Fig. 2, these bus bars extend the length of the plating bath, and are connected to the positive generator terminal, for feeding the heavy plating current from the positive generator terminal to the plating racks.

For returning the plating current from the contact rolls 9 to the negative generator terminal.

3 each contact ron is provided, as stated, with a pair .of metal contact 7 shoes, composedfpreferably of a .bronze alloysuch as copper and 10% tin, 'or'other appropriate material. Each of these contact shoes consists, as single arcuately-shaped piece of metal, which is provided at its leading end with a bolt-hole 19, through which extends a bolt 88, secured to the contact roll frame l9, for pivotally supporting the shoe, which rides, by virtue of its weight, upon the contact roll as shown in Figs. 2, 8. For increasing the life ofthe shoe, and offsetting the effect of wear, the cross-sectional thicknessof the shoe gradually increases from the leading end 19 to the trailing end 8|, as shown'in Fig. 9. Centrally disposed on the upper surface of the shoe is a flattened portion 82, containing tapped bores 83 for reception of terminal screws, attaching to the shoes flexible lead-in conductors 84, Fig. 8, of braided copper wire, or the like, the opposite ends of which are connected to a copper strip 85, which, in turn, extends and is connected to a bus bar 86, the latter consisting of an assemblage of copperstrips, extending, as shown in Fig. 2, the length of the plating bath and supported upon the insulating block 16, Fig. 6. This bus bar is, in turn, connected to the negative generator terminal.

I claim:

1. In an apparatus for feeding continuous strip material through successive plating zones, a first and a second pair of pinch rolls between which running clutch, an adjustable friction clutch and a second source of driving power, and means for driving said first roll pair from said second source through said friction and overrunning clutches.

2. In an apparatus for feeding continuous strip a pair of pinch rolls for feeding the strip, and means for drivingsaid rolls including, an overrunning, frictional clutch, comprising a first driven member frictionally engaging a second driven member, and a third driven member driven through overrunning clutch means by said second member, whereby said first member applies a frictional drive to said third member, but said third mom-'- ber is free to overrun in the direction of said drive.

3. In an apparatus for feeding continuous strip material through successive plating zones, a pair of. pinch rolls for feeding the strip, and means for driving said rolls including, an overrunning, frictional clutch comprising a first driven member frictionally engaging a second driven member, means for varying said frictional engagement, a third driven member, and pawl and ratchet means for driving said third driven member by said second membenwhereby said third member isfrictionally driven by said first member,

but is free to overrun in drive.

4. In an apparatus for feeding continuous strip the direction of said material through successive plating zones, a pair of pinch rolls for feeding the strip, and means for driving said rolls including, an overrunning,

- frictional clutch comprising three concentric driven members .disposed one within the other, means providing frictional engagement between the outer and intermediate members, and over running clutch me'ans interposed between the in shown. in Fig. 9, of a 4- a 2,842,850 .termediate and inner members, whereby a irictional drive is interposed between the outerand inner members, while the inner member is free to overrun in the direction of said drive.

5. In an apparatus for feeding continuous'strip material through successive plating zones, .9. pair of shaft mounted pinch rolls for feeding the'strip,

and means for driving said rolls including, interm'eshing gears carried by said shafts res ectively, and an over-running frictional clutch comprising three concentric. members disposed one :within the other, the outer meniber of which frictionally engages the intermediate member with means for adjusting said irictionalengagement, and the intermediate member of which drives through overrunning clutch means free to overrun in the direction of said drive.

6. In an apparatus for feeding continuous strip material through successive plating zones, a first and a second pair of pinch rolls, between which the strip is fed, said first mentioned pail of pinch rolls being interposed between successive plating zones and being located in advance of said second mentioned pair of pinch rolls, saidroll pairs being disposed in sequence in the direction of strip feed, means for applying a continuous positive drive to said second pair of, rolls, and means including overrunning, frictional slip clutch means for driving said first pair of rolls.

'1. In the feeding o'f continuous strip material in the inner member, 7 whereby the outer member may irictionally drive. the inner. member, while the inner member is- -betweeri a first anda second pair or pinch rolls disposed in'sequence respectively in thefdirection of said feed, the method of operation comprising.

applying-a positive driving iorceto the rolls of said second pair and applying a flexible drive through an overrunning, frictional clutch to the rolls of said first pair, and so adjusting the drives on said first and second roll pairs that the rolls of the first pair normally apply force to feed the 10 strip without slippage thereon, at a rate the same 'as the rate of-ieed oi the strip by the rolls of the second pair and with the strip maintained substantially free of slack between said pairs of rolls.

8.- In an apparatus for feeding. continuous strip material through successive plating zones, a first and a second pair of pinch rolls disposed in sequence respectively in the direction in which the strip is fed, said ilrst mentioned pair of pinch rolls being interposed between successive plating 2o zones and being located in advance 0! said second i mentioned pair of pinch rolls, means for applying a positive drive to said vsecond roll pair, and means for driving said first r011 pair including, a

' clutch having a first rotatable member frictional- '1y engaging a second rotatable member, and having a third rotatable member also including an overrunning clutch. means for driving said third member by said second member, means applying a positive'drive to said first member, and means forv driving said pinch rolls from said third mem'-' ber.

JOHNl FERM CERTIFICATE OF CORRECTION. Patent No. 2,5h2, 5o. February 29, 191m.

JOHN F. PERM.

7 It is hereby certified that error appears in the printed specification of the above numbered patent requiring correctiones followsz-Page b second column, line 5, claim 7, f "drive" read -driving foroe--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Pater 1t Office.

Signed and sealed this 16th day of May, A. D. 19%.

Leslie Frazer (Seal) I Acting Commissioner of Patents.

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