US1819603A - Electroplating apparatus - Google Patents

Description

Aug. 18, 1931f J. w. HUGHES 1,319,603

ELECTROPLATING APPARATUS Filed Sept. 2l, 1928 2 Sheets-She 2 INVEN TOR.

. JAMES W. HUGHES. BY

A TTORNEY.

Patented Aug. 18, 1931 UNITED STATES PATiszNT OFFICE JAMES W. HUGHES, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T BUDD WHEEL COMPANY, PHILADELPHIA., PENNSYLVANIA, A CORPORATION 0F PENNSYL- VAN IA ELECTROPLATIN G APPARATUS Application -led September 21, 1928. Serial No. 307,397.

plating operations are carried on continu# ously and automatically.

Among the primary objects of this invention is the provision of an apparatus which is capable of automatically and sequentially subjecting the articles to be plated to a series of successive treatments whereby to secure a more uniformly plated product than is now obtainable.

A further object of the invention is the provision of an apparatus for electroplating cap nuts and other small articles, the apparatus being operable to automatically and continuously advance the articles through the several baths which are generally employed in the plating process.

A further and important object of the invention is the provision of means for automatically changing the point of contact between the article to be plated and the cathode terminal of the electrolyte bath during the passage of the article through the bath,

thereby eiecually precluding the possibility of certain portions of the article receiving less coating than the remaining portions. One of the greatest difliculties encountered prior to this invention has been to attain an absolute uniformity of coating over the entire externalsurface of the Work, this difficulty being due principally to the fac'. that no adequate provision was ever Iliade for constantly shifting the Work as it advanced through the electroplating bath such that no single point thereof remained in contac'; with the cathode terminal.

A further object ofthe invention is the provision of a continuous line of different treating baths in combination Withmeans for automatically causing the articles to be plated to be progressively advanced in continuous succession through these baths, this means being operative to successively feed the articles into 011e end of one bath for subsequenty discharge from the opposite end thereof into the adjacent end of the next bath and so on in continuous sequence and without intermediate manual handling.

A further object of the invention is the provision of an apparatus employing for each bath a continuous conveyor equipped with a series of Work propelling elements, which in certain instances may form the cathode terminals of the electrolyic' bath, these elements being so arranged that they are each operable to propel one or more of the articles to be plated through that particular bath with which said elements are associated, each of the baths being in turn provided with a Work guiding trough 'the bottom of Which is of irregular formation such that as the articles are propelled therethrough they are tumbled about to expose every portion of their external surfaces to the action of the bath. l

A further object of the invention is the provision of means for preventing excessive deposition of metal on the work propelling elements Without interruption of the current and without affecting the constant shifting of the Work with respect to the cathode terminals, the result being that While very little, if any, metal is electro- -5 deposited upon the propelling elements no part of the external surface of the constantly shifting work is shielded from the metallic deposit.

A still further objectof theinvention is the provision of an apparatus capable of securing an' increased output of plated articles in a given -time with the expenditure ofk minimum effort, the articles treated by this apparatus being each provided with a plated coating of uniform thickness in every portion of' its external surface.

Other. objects and advantages of the invention will be apparent more fully hereinafter.

With the above objects in mind, the invention consists substantially in the combination, construction, arrangement and relative arrangement of parts, all as will be described more fully hereinafter, as shown in the accompanying drawings and as finally pointed out in the appended claims. lVhile the particular forms of the invention, as described hereinafter and as shown in the accompanying drawings, are designed to plate 100 cap nuts for automobile wheels and the like, it is to be clearly understood that the invention is in no sense limited to use with or for the plating of any particular article or device, it being obvious that various features thereof are applicable for general use'in.-

electroplating machines irrespective of the character, shape or form of the articles to be treated. It is to be furthermore understood that the accompanying drawingsillustrate what is regarded at present as the preferred forms and embodiments of the invention and that the invention may be changed in many respects without'departin essentially from the spirit or scope thereo as defined in the appended claims.

In the said accompanying-drawings:

Figure 1 is a longitudinal section through a portion of the apparatus constructedin accordance with this invention;

Figure 2 is a top plan view of the receiving end of the tanks;

Figure 3 is a horizontal sectional view taken on the line 3 3 of Figure 1 showing the discharging end of the tank;

Figure 4 is a longitudinal vertical sectional view taken on the line 4 4 of Figure 3;

Figure 5 is a transverse vertical sectional view taken on the line 5- 5 of Figure 1;

Figure 6 is a transverse vertical sectional view through a modified form of apparatus embodying the features of this invention; and

Fi re 7 is a sectional view taken on the line -7 of Figure 6.

Referring now to the ticularly to Figures 1 to 5 thereof, it will be seen that the apparatus of this invention comprises a series oftreating tanks arranged end for end to provide a continuous line of tanks through' which the articles to be plated may be successively passed. As many tanks may be employed as are necessary for treating the work before it is finally delivered from. the apparatus. The drawings illustrate an apparatus for electroplating cap nuts but, as explained hereinbefore, the apparatus may be employed with equal effect and efficiency in plating articles other than cap nuts.

tank or tanks wherein the articles to be plated are subjected to a bath containing lye or other suitable cleansing fluid for removing any grease, oil or dirt that may have been on the., articles. From the cleaning tank or tanks the articles are passed into a rinsing tank for ridding the articles of all .traces of the cleaning Huid. The articles then pass from the rinsing tank into the plating tank wherein the articles are subjected to a bath of electrolyte suitable for the plating process. After leaving the plating tank or tanks the article may again be passed Ythrough a rinsing tank. If the articles are to be plated successively with different drawings and par- The first of the series ofy tanks is usually designated as the cleaningv metals so as to provide upon the external surface thereof superimposed layers of metal, such as copper, nickle and silver, (as is done in high-grade silver plating) 'the articles may be passed through suitable rinsing tanks arranged immediately in advance of and immediately after'each of the separate plating tanks which may be employed.

In the drawings, only the plating tanks are shown, these tanks being designated generally by the reference numeral v10. Inasmuch as the mechanism for progressively advancing the work through the apparatus is the same for each tank, irrespective of whether the tank is employed for cleansing, rinsing or plating purposes, only one of these mechanisms has been shown in its entirety, the adjacent mechanism-for the next succeeding tank being only partially shown. ,These article propelling mechanisms are designated generally by the reference numeral 11. For convenience of description that end of each plating tank 10 which receives the articlesto be plated is termed the box of considerably greater length than width or depth. Arranged uponthe bottom of the tank and extending between the end walls 14 thereof is an upwardly presenting channeled member 15, formed preferably ofporcelain or other such material, this member constituting a trough 16 along'which the articles to be plated may -be advanced in the manner to be described more fully hereinafter. As appears most clearly in Figure 5, this porcelain channel l5 is of an overall width and depth respectively less than the effective width and depth of the tanklO, the cross sectional area of the channel ybeing such as not to materially reducelthe capacity of the tank 10. The tanks 10 ,are each'filled4 with a suitable electrolytic solution, lthe level of which is normally maintained immediately below the upper edges'of the tank. Preferably, the channel'l is arranged centrally between the side walls 13 of the tank. It will be observed that the ends of the channel 15 are curved upwardlv and toward the opposite -end walls 14 of uthe tank such that the botous passage for the lwork throughout the entire series of baths. A

Extending longitudinally along and projecting inwardly from the upper'edges of the sidewalls 13 of the tank 10 are a pair of metallic plates 18 secured in position by the screws 19. The free inner edges of these plates terminate in vertical planes arranged intermediate the proximate side walls of the channel 15 and the tank 10. Secured to the under surface of each of the plates 18, preferably by the screws 20, is a second metallic plate 21, the inner edge of which has formed thereon a relatively wide flange 22 providing a shoulder 23. This shoulder 23 and the inner edge of the plate 18 cooperate to form therebetween a relatively shallow channel or runway 24, -one such runway being provided to either side of the trough 16. If desired, the plates 18 and 21 could be made integral and the longitudinally extending runways 24 could be formed in the upper surface thereof, it being understood that in either form the runways are spaced apart to provide a centrally arranged longitudinally extending opening 25 in the top of the tank through which access is had to the trough 16.

Suitably journalled above the tank adjacent each end thereof are a pair of rotatable shafts 26 upon each of which is secured a pair of sprocket wheels 27 for driving the endless conveyor chains 28. The wheels 27 are so arranged that the lower sections of the chains 28 travel respectively in the runways 24 provided in the top of the tank 10, thereby precluding any tendency for the chains to sag at points between the sprocket wheels. For reasons to be explained more fully hereinafter, the lower chain sections are in continuous electrical engagement with their respective runways 24. As appears most clearly in. Figure 1, each chain comprises a series of interconnected links 29, each of these links being in turn provided with an inwardly projecting tab or equivalent element 30.

. Intel-connecting each pair of opposed tabs 30 is a transversely extending link or strap 31, each strap being detachably secured in position by bolts 32 passing through suitable apertures provided in the superimposed portions of the tabs and straps. It will thus appear that the conveyor adapted to be driv en by the sprocket wheels 27 includes a plurality of uniformly spaced, transversely extending straps, the intermediate portions of which are caused to move successively over the longitudinally extending opening 25 in the top of the tank 10. Suitably secured to each of the straps 25 is a cathode element 33 in the form of a transversely arranged plate` one branch 34 of which is bent over the inner surface of its supporting strap for securement Vthereto by a suitable wing bolt 35. As appears most clearly in Figures -land 5, these cathode plates, which project outwardly from the conveyor, are each of a length and widthdesigned to permit the j lower ends thereof to pass freelybetween the side walls of the porcelain trough 16. The cathode plates are each electrically connected to their respective supporting straps which latter are in turn electrically connected to the conveyor chains 28.

The electrolytic bath is supplied with current frompa suitable source of supply (not shown), the negative terminal of which is connected in any preferred manner to one or both of the metallic plates 18 and 21. The positive terminal of this source is suitably connected to the anode conductors or bus bars 36 which extend along the upper edges of t-he side walls of the porcelain trough 16. N ot only are the plates 33 employed as cathode elements, but they are also utilized as the means for propelling the work through the trough 16. As appears clearly in Figure 1, the articles to be plated, in this instance the cap nuts a, are received at the receiving end of the tank 10, one or more nuts' being propelled therethrough by each of the continuously advancing cathode plates 33. Inasmuch as these plates are always in contact with the nuts as the latter are propelled through the trough 16, the current which is derived from-the anodes 36 passes through the electrolyte to the nuts being plated and finally to the cathode plates 33 and from them to plates 18 and 21 and then to the negative terminal of supply, the

result being that there is continuous deposition of metal upon .the nuts as they are progressively advanced through the electrolytic bath.

As mentioned above it is one of the primary objects of this invention to insure the uniform plating of every portion of 'the work and in accordance with this object it will be observed that the bottom of the trough 16 is given van irregular formation, as at 37. Preferably this irregular formation is obtained by forming the trough bottom with alternate transverse .ridges andv grooves which operate to constantly tumble the nuts about as they are propelled along the'bottoin of the trough. There is thus provided an effective meansl for automatically changing exception of that portion which contacts With the Work. The sleeves 38, if desired, may be removable.

Figures 6 and 7 show a modified construction of the apparatus wherein the propelling members are separate and distinct from the cathode elements. In this mod `v ified arrangement a longitudinally extendingporcelain member 40 is employed which differs from the member 15 shown in Figures l to 5 in that it is provided with a plurality of separate relatively narrow troughs 41 in place of the single wide trough 16 hereinbefore described. The propelling members 42, which are secured to the conveyor in substantially the same mannerv as the members 33 of Figure 1, differ from the members 33 in that the free ends thereof are each slotted, as at 43, to provide a' plurality of projections 44 arranged to' travel respectively through the individual Vtroughs 41. In an arrangement of this sort only one article may be propelled through each trough 41 by one of the projections 44. Deposition of metal upon the propelling members 42 is eifectually precluded by covering the submergible portions thereof with suit-- able insulation 45.

Arranged upon the bottom of each of the individual troughs 41 is a longitudinally extending bus bar 46 constituting the cathode elements of the electrolytic bath. In order tol insure constant agitation of the articles to be plated as they are advanced along these cathode bars through the troughs 41, the upper surface of each bar is corrugated, as at 47, (see Fig. 7) to provide an irregular formation along the bottom of its respective trough. By reason of the fact that the Work is constantly in contact with the bus bars 46, which latter are connected to the negative terminal of a suitable source of supply (not shown), there is a continuous depositmn of metal upon the work. Furthermore,7 due to the fact that these cathode bus bars are corrugated the Work, as it is progressively advanced through the troughs 41, is constantly tumbled about with the result that no one point thereof remains in contact with the cathode bars.V Uniformity in plating is thus automatically., insured.

As most clearly appears in Figure 1,`

when the nuts or other articles to be plated approach the end of a particular treating bath, the propelling members operate to advance the articles upwardly along the curved portion of the trough for subsequent discharge into the receiving end of the next adjoining tank. In this manner, the articles are progressively advanced through the continuous line of tanks Without necessitating any manual handling throughout the entire process of plating.

It will be understood, of course, that various changes may be. made from time to gitudinally along the bottom of said tank,.

thi*J opposite ends of said trough being curved upwardlytoward the upper edges of the tank and the bottom of said trough between the curved portions thereof being corrugated, and means therealong operatively associated with said tank for continuously propelling a succession of articles to be vplated along the corrugated bottom and curved portions of said trough,- said corrugated bottom being operative to eii'ect a cons'tant shifting of the articles during their passage therealong.

2. In an electroplating apparatus, in combination, a tank adapted to contain an electroplating solution, a corrugated work guiding path extending longitudinally through said tank, and an endless conveyor mechanism operatively arranged above said tank, said mechanism including a plurality of work propelling members arranged in transverse relation to said corrugated path and adapted to move longitudinally through said tank with the free ends thereof in close proximity to said path.

f 3. In an electroplating apparatus, in combination, a tank adapted to contain an electroplating solution, said tank being provided in its bottom with a` longitudinally extending path having corrugated surface along which the work may be propelled, an endless conveyor mechanism operatively arranged above the tank, said mechanism including a plurality of work propelling members arranged in transverse relation to said longitudinally extending path for movement through said` tank with the free ends thereof in'close proximity to the corrugated surface thereof, 'means for supplying current to said solution, and'means foriinsulating said members against excessive deposition of metal thereon.

4. An lapparatus for electrolytically coating small articles such as cap nuts comprising a tank containing an electrolyte, a conveyor having a plurality of depending arms extending into said tank into proximity with the bottom thereof and adapted to push successive articles through the electrolyte contained in the tank, the bottom of said tank being corrugated. whereby to effect a tumbling of said articles during their progress through the tank.

In testimony whereof 'I hereunto aflix my signature.

JAMES lV. HUGHES.

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