US2624728A - Electroplating barrel - Google Patents

Description

Jan. 6, 1953 s. DUBPERNELL ETAL 2,624,728

ELECTROPLATING BARREL 5 Sheets-Sheet 1 Filed July 14, 1949 INVENTORS GEOEQE DUBPERNELL ST PH NM.MA/2T/N AT TORNEY Jan. 6, 1953 e. DUBPERNELL EI'AL' 2,624,723

ELECTROPLATING BARREL Filed July 14, 1949 S Sheets-Sheet 2 INVENTORSZ GEORGE DUBPERNELL S EPEN M. MARTIN BY: v

ATTORNEY Jan. 6, 1953 G. DUBPERNELL ETAL 2,624,723

ELECTROPLATING BARREL Filed July 14, 1949 s Sheets-Sheet :5

Fig. 8

INVENTORS. GEORGE DUBPERNELL 3 TE H M. MART/N ATTORNEY Jan. 6, 1953 G. DUBPERNELL ET AL 2,

ELECTROPLATING BARREL Filed July 14, 1949 5 Sheets-Sheet 4 INVENTORSL GEORGE DUBPERNELL jHEN M. MART/N BY'. I

IA TTOR 35% Jan. 6, 1953 G. DUBPERNELL EI'AL 2,624

ELECTROPLATING BARREL Filed July 14, 1949 5 Sheets-Sheet 5 AUTOMATIC 140 HOPPER FEED INVENTORs'. GEORGE DUBPERNELL jg: E MMAET/N BYI {{TORNEY 3 Patented Jan. 6, 1953 ELECTROPLATIN G BARREL George Dubpernell, Watertown,

Conn, and

Stephen M. Martin, Glen Ridge, N. J assignors to United Chromium, Incorporated, New York, N. Y., a. corporation of Delaware Application July 14, 1949, Serial No. 104,757

1 Claim. 1

This invention relates to electroplating barrels, particularly for use in electrodepositing metals which are difficult to plate.

Chromium has been a metal which has presented difliculties to electroplating in barrels. Good electrical contacts, anode design and spacing, and speed of rotation of the barrel are important. Hygroscopic and corrosive constituents of the plating solution make it important to avoid fouling and corrosion of bearings and electrical connections, especially sliding connections. It is also important to remove the anode from the plating solution when current is not flowing. The feeding and removal of articles from the barrel without removal of the barrel cylinder from the plating solution has been troublesome.

The present invention provides an electroplating barrel Well adapted for electrodepositing difficult metals such as chromium, which is sturdy and mechanically simple, and in which good electrical and bearings performances are obtained. The anode support construction provides for ready disassembly of the anode from the barrel, ready substitution of anodes, ready adjustment of anode to cathode spacing and ready removal of the anode from the solution without disassembly. The invention also provides novel and useful means for, and constructional adaptation to, feeding and removal of articles to and from the barrel cylinder.

Three embodiments of the invention are illustrated in the accompanying drawings, wherein Figure 1 is a top plan view of one embodiment;

Figure 2 is a. vertical sectional view of the construction shown in Figure 1;

Figure 2a is a detail sectional view of one corner of the barrel cylinder, showing the insulation;

Figures 3 and 4 are end elevations, partly in section on line X-X, Fig. 1, Fig. 3 showing the an ode in the solution and Fig. 4 showing the anode rotated on its support out of the solution;

Figure 5 is a transverse section through the barrel cylinder showing scoops for removing plated articles from the barrel cylinder;

Figure 6 is a view similar to Fig. 5 and showing the scoops for depositing and removing articles from the barrel cylinder;

Figure '7 is a sectional detail for the barrel cylinder;

Figure 8 is a view mainly in vertical section illustrating a second embodiment and incorporating means for continuously feeding and removing articles from the barrel cylinder;

Figure 9 is a top plan view of the construction illustrated in Fig. 8;

view of a bearing Figure 10 is an end elevation of the barrel cylinder, partly in transverse section, at the delivery end of the cylinder;

Figure 11 is a view in end elevation of the barrel cylinder at the feeding end thereof;

Figure 12 is a detail View showing a means for adjusting the height of the anode supports 15 and H and thereby adjusting the spacing between the anode and the work resting on the inside of the barrel cylinder;

Figure 13 is a partial vertical sectional view of a third embodiment of the invention;

Figure 14 is a plan view of the feed chute seen in Figure 13.

Referring to said drawings, numeral [0 designates a, suitable tank for containing an electroplating solution and numeral l2 designates a cylindrical barrel rotatable on a horizontal axis, and circumferentially continuous, as shown. Numeral l4 designates a means for controlling the temperature of the electroplating solution in the tank, such as commonly employed, and as here shown, consists of a coil of pipe immersed in the solution and having an inlet 15 and an outlet I6 for a cooling or heating medium such as water or steam. Means for stirring the solution may be provided, as indicated by numeral 20. Spray and fumes above the level of the solution in the tank may be drawn away, as usual, by any suitable form of means, as the fan 22 driven by motor 23. The level of the solution in the tank may be controlled by an opening 25 in one of the walls of the tank, and a down-spout 26 which leads to a suitable overflow receptacle.

The barrel cylinder i2 is made of a suitable electrical conducting material as steel and is open at both ends to the solution in the tank, as indicated at 28, 29. The electroplating solution may circulate through the barrel, through the end openings. Flanges 30, 3| are provided at the two ends of the barrel cylinder to prevent work being electroplated falling out. Articles being electroplated in the barrel cylinder rest in electrical contact with the inner cylindrical metal surface of the barrel cylinder. That is, the inner cylindrical surface is base metal. The flanges 3i), 3! are faced with or formed of insulating material as indicated at 33, 34 to prevent these parts from diverting electric current from the work to be plated. The interior of the barrel cylinder is provided with a plurality of longitudinal ribs 36 preferably of insulating material to efiect periodic tumbling of articles within the cylinder, as the cylinder rotates.

With electroplating barrels in which articles to be plated rest (with periodic tumbling) in electrical contact with the inner metal surface of the plating barrel, it is a difficult matter (particularly with plating solutions such as the chromic acid type of chromium plating solution) to obtain full coverage and uniformly appearing plate on work to be electroplated. The difliculty of plating is also affected by the type of work to be electroplated, that is, by size, height, flatness etc. of the work. It has been found to be important in overcoming these plating difficulties to avoid diversion of the current between the anode and the work on the inner surface of the plating cylinder, and also to provide for adjustment of the spacing between the anode and the inner surface of the plating cylinder, i. e., between the anode and work in contact with the inner surface of the plating cylinder, as described later on.

For preventing diversion of plating current from the Work it has been found to be important 2' to insulate all parts of the plating cylinder except its inner cylindrical surface. In addition to the insulation 33, 34 on the flanges 30, the outer surface of the metal cylinder I2 is insulated, as indicated at 35, Fig. 2a.

The barrel cylinder is rotatably supported at one end only, above the level of the plating solution in the tank, as shown, so that only a portion of the circumference of the barrel cylinder is submerged as it rotates. the barrel cylinder is ashaft 40 attached to the cylinder at its axis, by any suitable means, as a spider 42 and a hub 44 having a split, tapered, threaded end 45. The end of shaft 49 projects into the hub 44 and is clamped inside the hub by means of a nut 41 which nut forces the split end of the hub into binding electrical contact with the shaft as it is screwed on to the threaded, tapered end of the hub. The shaft 40 is supported in bearings 50, which may be fastened on to a frame 52 attached to the tank It]. As the tank and frame are usually of metal, the bearings 59, 5] are insulated from the frame, as indicated at 53, Fig. 7, to the end that the barrel cylinder I2 and shaft 40 are insulated from other parts of the mechanism. The shaft 40 and barrel cylinder 12 mounted thereon is rotated at a suitable speed by a suitable mechanism, such as an electric motor reduction-gear unit 55, having an output shaft 56. Mounted on the shaft 56 is a pulley 57 and this drives a pulley 58 fastened on the shaft 40 through a non-conducting chain or beltfis.

Means are provided for connecting the barrel cylinder in an electric circuit as a cathode, and these means are arranged remote from the solution in the tank and fumes or spray arising therefrom, so as to thereby protect the electric contacts from fouling and causing resistance to the flow of the current. To this end, the remote end of the shaft 40 may be provided with an electrical conducting disk, which, as shown, may be integral with pulley 58. Brushes 6|, 62 are provided, and these bear on opposite sides of the pulley 58 so as to have sliding contact therewith. The brushes are carried by a brush holder 64 attached to an insulated bracket-65 carried by the frame 52, and the brush holder 64 is connected with the oathode bus bar 61.

Numeral designates the anode, and this is carried by a shaft 12 which projects through the open end 28 of the barrel cylinder opposite end 29 at which the barrel cylinder is supported, into the interio of the cylinder. The anode is removably attached to the shaft as by means of screws or bolts 13 to permit the substitution of The rotatable support for 7 anodes of different shape and diametrical pro jection for best performance with different types of articles to be electroplated. The shaft 12, carrying the anode, is supported by means which function to permit the anode to be removed from the plating solution by a rotation of shaft 72, and which also permits the read removal of the shaft and. anode from the barrel cylinder and tank. To this end, the shaft 12 has a cantilever support in a crotch type bearing 15 which opens upwardly, and a hook type bearing 71 which opens downwardly. The crotch type bearing 75 may be, as shown, supported on the upper side of the tank, and the hook type bearing 'i'i may be arranged on an arm 19 attached to and projecting outwardly from the side of tank It. The anode is electrically comiected in a circuit by suitable means, as a flexible conductor electrically connected to the shaft 72. The shaft 12 is insulated from the tank by suitable insulation as indicated at 82, 83. The height of the anode bearings i5 and 11 is adjustable. A suitable construction is illustrated in Fig. 12. As there shown, a bolt a passes through a hole in the side of the tank and through a slot or series of holes in a bracket 15b which carries the bearing 75, and by loosening and tightening the bolt 15a, or nut thereon, the height of the bearing f5 may be adjusted and fastened in adjusted position to thereby obtain an optimum spacing of the anode it from the Work on the inside of barrel cylinder E2. Likewise, a bolt 17a passes through a hole in bracket 79 and through a slot or series of holes in a part 111) of bearing 71. By loosening and tightening the bolt 11a, or a nut thereon, the height of bearing T! may be adjusted and fastened in adjusted position. (along with the adjusted position of bearing 75) to obtain the aforesaid optimum spacing of the anode 10 from the work resting on cylinder I 2. Work like thin washers require a different spacing of the anode from the bottom of the cylinder from the spacing for studs, for example, for good evenly appearing, fully covering plating. For work of different sizes and shapes adjustment of the anode spacing is also necessary for good plating results.

Work may be introduced and removed from the cylinder by hand or trough via the open end of the electroplating barrel cylinder l2. For advantageously removing, or removing and supplying articles, from the interior of the electroplating barrel cylinder I2, a demountable trough 85, as illustrated in Fig. 5, or a double trough 81, as illustrated in Fig. 6, may be provided. The trough extends from side to side across the interior of the cylinder 12 and bears closely against the interior surface of the cylinder and has an open side 99 in the direction of the rotation of the cylinder. The trough or 87 is fastened against the interior of the barrel cylinder by spring strips 93 which are fastenedto the ends of the trough, projecting outwardly over the flanges 3.8, 3| of the cylinder, and then'upwardly over the exterior surface of the cylinder so as to bear with spring pressure against the exterior surface thereof, and thereby hold the trough against the interior surface of the'barrel cylinder. The trough 85 or 8'! acts tov scoop or collect articles from the interior of the barrel cylinder as it revolves through the lowe arc with the rotation of the cylinder. The double trough 8?, illustrated in Fig. 6, also has the function of depositing new work in the barrel cylinder for electroplating. The trough 81 is open at its side 95 opposite the side 99, and is provided with a middle partition 91. Articles may be placed in the trough 81 at the side of the partition 91 through the opening 95, and as the barrel cylinder rotates. carrying the trough 81, articles will be collected in the trough through the opening 90, and, as the rotation of the barrel cylinder continues, articles will be deposited in the bottom of the barrel cylinder from the trough through the opening 95.

A second embodiment of the invention having means for continuously feeding articles into and from the barrel cylinder is illustrated in Figs. 8 to 11. In Figs. 8 to 11, the shaft 40 is hollow as indicated at I and is provided on the inside with a spiral rib I02 for conveying articles lengthwise through the interior of shaft 40 into the interior of barrel cylinder I2. Articles to be plated may be fed to the conveyor formed by the spiral rib I02 on the interior of shaft 40 by a hopper I04 which may be supported in suitable manner as by means of an arm I05 attached to the frame 52. The barrel cylinder I2 is also provided on its interior with a spiral rib I01, in addition to the transverse ribs 33. The ribs 36 and I0'I may be of metal, when low, but are most advantageously formed of an electrical insulating material, so as to avoid diversion of current from the work resting on the cylinder I2. These strips are also, chemically inert to the plating solution. Vinylite meets with these requirements. The

spiral ribs I07 act to slide articles lengthwise of the barrel cylinder as they are being electroplated. When the plated articles reach the side of the barrel cylinder opposite the supporting shaft it, they are picked up by pockets I I0 fastened to the cylinder adjacent to the flange 30, and as the pockets rise in the course of the rotation of the cylinder the articles collected therein rise with them, and, when the pockets reach a position at the top of the cylinder, the collected articles are dumped therefrom, and an inclined tray H2 is provided to catch them. The tray I I2 may be removably supported at the side of the tank It as indicated at H2. The tray H2 is supported at an incline, and projected inwardly through the open side 28 of the barrel cylinder and outwardly over the side of the tank I0. As here shown, a tank I I6 may be provided at the side of tank It, containing water for rinsing the plating solution from the plated articles. The plated articles may be then readily collected from the tank H3.

A third embodiment of the invention, illustrating another means for continuously feeding articles into and from the barrel cylinder is illustrated in Figs. 13 and 14. The structure of the embodiment of Figs. 13 and 14 is generally the same as that of Figs. 1 to 4. In this third embodiment the barrel cylinder I2 is provided with an inside spiral rib I (similar to the rib III'I, Fig. 8) constructed and arranged to feed articles resting on the cylinder I2 from the shaft supported end 29 toward the opposite end 28, as the barrel-cylinder I2 is turned by its driving mechanism. As in the structure of Fig. 8, when the plated articles reach the side of the barrel cylinder opposite the supporting shaft 40 they are picked up by pockets I23 fastened to the cylinder adjacent to the flange 33, and, as the pockets rise in the course of rotation of the cylinder, the articles collected therein rise with them. When the pockets reach a position at the top of the cylinder, the collected articles are dumped therefrom, and an inclined tray I is provided to catch them. The tray I30 is supported at an incline, and projected inwardly over the side of tank I0. The plated articles slide from tray [39 6 into a tank II6, similar to the plated articles in Fig. 8.

Articles to be plated are fed into the cylinder by an electrically non-conducting or surface insulated chute I which projects through the open end 28 of the cylinder, at one side of the anode I0, and extends at its lower end to a point near the shaft supported side 29 of the barrel cylinder. The chute I35 advantageously has the form of a tube, which may be expanded at its outer end to provide a funnel I36, and which at its inner end is bent to one side at an angle of approximately 90, as indicated at I31, so that it may face the cylindrical wall of the cylinder I2. By bending the end I31 as described, articles sliding down the chute I35 are deflected on exit toward the cylindrical wall of the cylinder, and are thereby kept from passing out of the cylinder I2 through the openings in the end 29. Articles may be fed into the end I36 of chute I35 by hand. However, an automatic hopper feed of any well known construction will usually be employed to feed articles to be plated to the end I36 of the chute. An automatic hopper feed is diagrammatically shown in Fig. 13 at I40.

Operation The barrel cylinder I2 is rotated at a suitable speed from the motor gearing unit through pulleys 51, 58 and belt 59. For chromium plating the speed of rotation should be such so that the articles being plated within the cylinder are intermittently tumbled. The longitudinal ribs 36 prevent sliding of the articles on the inside of the cylinder and assist in tumbling.

Plating current from a generator passes to the anode from conductor and shaft 12. Current passes from the anode through the plating solution to the work resting in electrical contact with the cylinder I2, and then from the cylinder I2, hub 44, shaft 40, disk or pulley 58, brushes BI. 62, and cathode bus-bar 61 back to the generator.

The temperature of the plating solution is re ulated by controlling the flow of a thermal medium through the coil I4.

The exhaust fan 22 operates to remove fumes and spray arising from the surface of the plating solution in the tank I0. The bearings 50, 5| and the brushes BI, 62, being remote from this exhaust, are thereby protected from fouling by the fumes and spray which would cause variations in the plating current. The electrical connections of the motor 23, motor 55 and anode are likewise V protected.

When plating of the articles in the barrel cyl-- inder I2 has been completed, in the construction. illustrated in Figs. 1 to 6 inclusive, the workmen. insert either a trough or a trough 81 longitudinally across the interior of the barrel cylinder. The spring strips 93 project alongside the outside: of flange 30 and thetongues of the strips bear:

on the exterior of the cylinder, and press the! trough against the interior of the barrel cylinder;, with the edge of the opening bearing closely, against the cylinder. The position of the trough: at the time of attachment is shown in full lines: in Figs. 5 and 6. As the barrel cylinder rotates, and the trough passes through the bottom-most; position of the cylinder, the plated articles in the cylinder are collected, as illustrated in dotted. lines in Figs. 5 and 6, and then lifted up to a. position above the level'of the solution in thetank. The workman then separates the trough from the barrel cylinder, withdraws it through. the open end 28 of the cylinder, and then empties the contents of the trough. To deposit articles to be plated in the barrel cylinder at the same time that plated articles are collected from the cylinder, the double trough illustrated in Fig. 6 is used. Articles to be plated are put into the side of the trough which opens upwardly. As the barrel cylinder rotates, the trough is carried through the lower position of the cylinder, collecting plated articles through the opening 90, as heretofore described, and, shortly thereafter, as the trough rises, the unplated articles are deposited in the barrel cylinder through the open side 95 of the trough. See the dotted line posi tion, Fig. 6.

When no more articles are to be plated, the anode I is moved out of the solution to prevent the formation of an insulating chromate film thereon. This is readily done by rotating shaft 12 which carries the anode until the anode is moved from the position shown in Fig. 3 to the I position shown in Fig. 4.

The shape and diametrical projection of the anode into proximity with the surface of the barrel is of importance in obtaining good plating results with different types of work. To make use of an anode better suited than another anode to the type of work being electroplated, the fastening means I3 are loosened or removed, and the proper anode substituted and then fastened in place.

To effect complete removal of the anode from the barrel cylinder and tank, as for replacing anodes, or for other purposes, the detachment is readily effected. The shaft I2- on its cantilever bearing I5 is pressed downwardly at its outer end and lifted upwardly at its inner end, and then simply lifted out of the barrel cylinder and-away from the tank. The shaft in, its tilted position free from the hook bearing I'I and the; crotch bearing I5 being open at the top, offers no ob.- structionto the removal of the shaft I2 and-Hanode I0. W

Referring to-Figs. 8 to 11', the operation of' the plating barrel is like that described in references to Figs. 1 to 6 except that the feeding of the articles into and out of the barrel cylinder: I2 is automatic;

In the construction illustrated in the later figures, the articles to be plated are fed, from the hopper I04 into the hollow in shaft 40, and are then moved forward into the barrel cylinder by the spiral rib I02. The-articles fall into the barrel cylinder at the end adjacent, the shaft. 40, and on reaching the bottom of the cylinder they are continuously fed lengthwise towardthe open end 28 by the spiral rib I01. While the articles arebeing plated, they are intermittently tumbled with the assistance of the ribs 36 and at the same time fed lengthwise along the'barrel cylinder by the ribs I07. At-the side 28 ofthe cylinder [2, the plated articles arepicked up by thepockets H9 and then lifted up in the course of the rotation of the cylinderto aposition where the-articles are dumped out ofthe pockets. This position is shown in Fig.8; The plated articles dumped fromthe pockets IIOv are caught'by'the inclined plate I I2, .and slide down theplate'to a place of delivery, for example a, water tank H6,

in which plating solution iswvashed from theticle into and out of the cylinder I2 is automatic, similar to the operation in Figs. 8 to 11. In Fig. 13, articles to be plated are fed into the end I38 of the chute I35, either by hand, or from an automatic hopper feed. The articles fed to the chute I35 slide down the chute and are discharged inside of the cylinder I2 adjacent the shaft supported end 29. From the shaft supported end 29 of the cylinder I2 the articles are continuously fed lengthwise towards the open end 28 by the spiral rib I29. They are also intermittently tumbled as in the embodiment of Fig. 8. At the side 28 of the cylinder, the plated articles are picked up by the pockets I25, dumped onto the inclined plate I30 and discharged into a washing tank I I8, similar to the operation in Fig. 8.

What is claimed is:

In an electroplating barrel for barrel plating articles with chromium or with other metals diflicult to electroplate comprising a tank for holding a plating bath, a rotatable open-ended articlesupporting metallic cylinder supported on the tank for partial immersion in the bath, a horizontal conducting shaft electrically and structurally connected at one end of the cylinder by means of which the cylinder is rotated, means for electrically connecting the shaft to the cylinder, an anode supported in the cylinder, means for rotating said cylinder shaft and the cylinder connected thereto, and means for connecting said cylinder and the anode in an electric circuit through the plating bath, the improvement in which said cylinder is imperforate, said cylinder having a conducting inner cylindrical surface and having electrical insulation covering the outer cylindrical surface thereof to avoid diversion of current between the anode and articles supported in said cylinder, said electrical connecting means between the cylinder and its supporting shaft comprising a split tapered threaded hub attached to the cylinder for receiving the shaft, and a nut for said threaded hub acting to force the split end of the hub into binding engagement and firm electrical contact with the shaft, said hub and nut also permitting the cylinder to be detached from the shaft, said means for rotating the cylinder and cylinder shaft comprising a conducting pulley on the cylinder shaft an'da non-conducting' driven belt'for driving said pulley, and said means'for connecting the cylinder and anode in an electrical circuit including contact'brushes in contactwith said conducting pulley.

GEORGE DUBPERNELL.

STEPHEN MI MARTIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 703,623 Taylor July 1, 1902 901,280 Daniels Oct. 13, 1908 1,185,946 Schulte June 6, 1916 1,609,357 Hulmer Dec. '7, 1926 1,789,443 Levin Jan. 20, 1931 1,835,643 Frost et a1 Dec. 3, 1931 1,899,679 Fink Feb. 28, 1933 2,133,324 Hosdowich Oct. 18, 1938 FOREIGN PATENTS Number Country Date 23,267 Great Britain of 1897

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