US1545942A - Electroplating - Google Patents

Description

July 14, 1925. 1,545,942

F. CONLIN ELECTRCPLSTI'SG File 12, 1925 2 Sheets-Sheet l INVENTOR 3 FreJen c/r [on/k2 04/65) Me /a/ed PM ATTORNEYS July 14, 1925. 1,545,942

F. CON'LIN ELECTROPLATING Filed Jan. 12 1925 2 Sheets-Sheet 2 f @LMMW {\TTORNEYS Patented July 14, 1525.

UNITED STATES 1,545,942 PATENT. OFFICE.

FREDERICK CONLIN, OF WESTFIELD, NEW JERSEY.

ELECTROPLATING.

Application filed January 12, 1925. Serial No. 1,831.

To all whom it may concern.

Be it known that I, FREDERICK CoNLIN, a citizen of the United States, residing at Westfield, in the county of Union, State of New Jersey, have invented certain new and useful Improvements in Electroplating; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertainsto make and use the same.

This invention relates to an improved brush for electrolytically applying metals, such as nickel, to conducting surfaces. One of the objects of the invention is to provide an improved means for applying smooth, dense, tenacious and continuous metallic films or platings. Another object of the invention is to eliminate the necessity of employing the commonly used electrolytic plating baths and to make it possible to apply metallic coatings of good physical properties to objects and articles which cannot readily be plated in the ordinary baths. Another object of the invention is to facilitate the application of metallic coatings of this character and to make it possible to apply metallic coatings of good physical properties in a rapid and easily performed operation. Other and further objects Wlll appear from the following description and illustration.

The improved brush of the present invention comprises a bristle head attached to a handle and an anode arranged within the bristle head so as to be wholly immersed in plating solution retained by the bristles. The anode is thus submerged in plating solution when the brush is in use so that the maximum area of the anode is in contact with the electrolyte in the brush and so that a more .uniform distribution of the flow of current through the electrolyte in the brush is promoted. The improved uniformity of distribution of the plating current assists in producing a metallic deposit of good physical properties and avoids burning of the metallic coating due to too great a current density over localized areas. The anode is advantageously made of the metal to be plated so that to some extent the anode replaces the metal content of the electrolyte in thebrush as it is deposited. The anode may be arranged so that it canbe replaced as it is dissolved or used up.

In one-particularly advantageous embodiment of the invention, the anode is constructed and flexibly supported in the bristle head so that it has some freedom of motion with the bristles. The anode, being entirely surrounded by the bristles of the brush, thus tends to move with the bristles when the brush is in use. Vear of the bristles is thus reduced and the danger of assists in retaining the electrolyte in the brush and also acts to hold the bristles in close contact with the anode. A web of this character promotes economy of the plating solution, particularly where the anode is made up of the. metal to be plated.

The invention will be further described in connection with the accompanying drawing which shows several brushes embodying the invention as well as a diagrammatic representation of the method of using the improved brush of the invention. It will be understood that this further description and illustration are for the purpose of eXemplification and that the invention is not limited thereto.

In the accompanying drawings Fig. 1 represents, partly in section, a brush embodying the invention.

Figs. 2, 3 and 4 show modified forms of the brush head illustrated in Fig. 1.

Figs. 5 and 6 show a somewhat different type of brush embodying the invention.

Fig. 7 shows a flat brush having a flexibly supported anode embodying the invention.

Figs. 8, 10 and 15 show modified forms of the brush illustrated in Fig. 7.

Fig.9 is a section on line 99 of Fig. 8.

Figs. 11, 12, 13 and let show anode ele'- ments employed in connection with the brush illustrated in Fig. 10.

Fig. 16 is a diagram showing the elec trical connections for using the brush of the invention in. electroplating conducting surfaces.

The brush illustrated in Fig. 1 is made up I of a separable brush head and a handle.

In the brush head the bristles 9 are cemented or otherwise secured in a base 10. The cementing agent employed should be resistant to the attack of the electrolyteused, for example, for use in nickel plating the bristles may be set in rubber. Arranged w1th1'n the bristles and supported by the base is an anode 11. This anode fits tightly in'a hole through the base 10 andis held in place thereby although it may be moved up and down to adjust, the distance between the end of the anode and the end of the bristles. The base 10, which may be of hard rubber or other insulating material, screws into the middle section 12 of the handle and this middle section is in turn attached to a handle 13 for the use of the operator. The middle section 12 may be of hard rubber or other insulating material and the handle 13 may be of wood or other suitable material. The electrical connection to the anode extends through a bushing 14 in the side of the middle section 12 to the chamber within this section where it is attached to the upper end of the anode 11. The electrical connection 15 to the anode is thus attached to the brush adjacentathe bristle end giving advantages in convenience and ease of operation in using the brush. By making the brush head readily separable, as in the brush illustrated, the type of brush head employed may be readily changed as required. l/Vhere a soluble anode is employed, it may be removed as consumed and a new anode inserted.

In using the brush, the anode in the brush is connected to the positive pole of a suitable source of direct current the negative pole of which is connected to the conducting surface to be plated as shown in Fig. 16. The brush is then saturated witha suitable electrolyte, as by dipping in the electrolyte solution and is then worked over the surface to be plated. In using the brush, it is necessary only to maintain contact between the bristles and the surface to be plated by a motion similar to that used in painting for a sufficient time to give a coating of the desired thickness but it is not necessary to work out the electrolyte solution as is done in applying oil paints and the like. In using the brush of the present invention the solution is electrolyzed in the brush and the metal is deposited atthe point of contact between the brush and the conducting surface to be plated. The movement of the brush bristles-over the conducting surface to be plated, which is the cathode, promotes effective depolarization at the cathode so that the plating operation proceeds smoothly and uniformly. The movement of the bristles about the anode, which is entirely surrounded thereby, also assists in preventing polarization at the anode. The distance between the lower end of the anode and the end of the brush bristles is adjusted to promote uniform distribution of current flow through the electrolyte retained by the brush without unduly increasing the resist ance through the brush, and the lower end of the anode is kept sufficiently distant from the end of the bristles to prevent a local flow of current, or a flow of an undesirably high density, from the anode to the surface to be plated. In'using the brush, however, materially higher current densities may be employed than are commonly used in the ordinary platingfbaths. The anode in the "brush may be composed of the metal to be fluoride, 30 gms. of boric acid and 2 gms. of

glucose per liter may be used at ordinary temperature with a potential between the anode in the brush and the conducting surface to be plated of from about 12 to volts. Voltages ranging from 6 to or more are also useful, and in general a volta e as high as can be used for the production 0 plate of satisfactory quality is employed to promote the speed of deposition. For

nickel plating, the anode is advantageously a nickel wire or wires or rod or plate or casting. With a brush in which the bristles extend approximately on each side of the anode the anode may be arranged about from the end of the bristles. Some adjustment of this distance may be desirable to secure the best deposit but the distance is not critical due to the anode-electrolyte and the electrolyte-cathode resistance-s. Current densities through the electrolyte in the brush of from 2 to 7 times those used in ordinary plating bath practice may be employed with the consequent increase in rapidity of deposit of the nickel. For example, current densities of as much as 0.17 amp. per sq. cm. or more may be used. In preparing a metal surface to be plated, it may be polished, for example by buffing with tripoli followed by Vienna lime, and then subjected to the plating operation after being washe with a caustic solution, such as a solution of caustic soda, to remove oil or grease. The metal deposit is smooth and has a polish corresponding to that of the metal before being plated. Ap-

parently due to the depolarizing action of' the movement of the brush bristles-over the cathode, the metallic plating has a good polish as it leaves the brush. Following the plating operation, the plated surface may be subjected to a further polishing operation if desired.

In Figs. 2,3 and 4 modified forms of brush heads which may be used in connection with the handle illustrated in Fig. 1 are Shown. In Fig. 2, the bristles 9 are set in a base 10 and an anode consisting of a plurality of more or less flexible wires 11 is arranged within the bristles. The distribution of the elements of the anode through the bristles of the brush promotes the uniformity of current flow through the electrolyte in the brush and the wires forming the anode, due to their flexibility, may yield somewhat tothe movement of the bristles when the brush is in use. In Fig. 3 the bristles S are set in a base 10 and an anode 11 is supported in the bristles by the base 10 The anode consists of a metal rod of which the end in the bristles is split and spread to promote uniform flow of current through the electrolyte in the brush. In Fig. 4 the bristles 9 are set in the base 10 and an anode consisting of a short tubular section 11 is arranged Within the bristles and is'su pported by connections extending through the base 10. This type of anode is of particular value in connection with relatively large circular brushes and the like.

In the brushes illustrated in Figs. 5 and 6 the bristles 16 are secured directly to the handle 17 and the anode 18 is supported within the bristles by an extension extending through the handle 17 to the upper end where the electrical connection 19 to the anode is made.

In the brush illustrated in Fig. 6, a porous web 20 is arranged about the upper end of the bristles of the brush and about the portion of the bristles within which the anode 18 is arranged. This Web, which may be of tubular wicking or the like, or an open mesh fabric, compacts the bristles against the anode in close contact therewith and also assists in retaining the electrolyte in the brush. A brush of this construction is of special value in plating surfaces from the underside. In working in confined spaces, the web about the brush also prevents the anode from working through the bristles and contacting with adjacent metal parts with the possibility of causing a short-circuit.

The anode of the brush illustrated in Fig. 7 consists of a fiat metal plate 21. In this brush the bristles 22 are secured directly to the handle 23. The anode 21 is supported by two connect-ions extending upwardly therefrom through holes in the base of the brush head and the handle. A greater or lesser number of such connections may be employed. These connections 24 are of flexible material and are fastened to the anode by welding or soldering. At their upper end, these connections are attached to a clamp 25 for securing the electrical connection to the anode. The anode is arranged somewhat below the base of the brush head so that the connections to the anode are free to bend for some distance above the anode. The anode plate 21 is thus free to move, within limits, with the bristles of the brush when the brush is in use. If the wires of the brush head illustrated in Fig. 2 are sufficiently flexible they may move similarly with the bristles of the brush when in use.

In the brush illustrated in Figs. 8 and 9 the bristles 22 are secured directly to the handle 23*. The anode consists of a plate 21 having projections 26 and is supported by conductingloops 27 extending upwardly through holes in the base of the brush head and the handle which also serve as connections to the anode. The loops 27 are connected at their upper ends to a clamp 25 for securing the electrical connection to the anode. The anode 21 is thus suspended within the bristles so that it is free to move with the bristles as they are displaced when the brush is in use. In the brush illustrated in Fig. 15, the anode plate 21 is suspended within the brush bristles 22 by a single loop 28 passing through a hole in the anode plate. The anode is thus suspended free to move laterally in any direction with the bristles. The loop 28 is connected to the clamp 25 and serves as the electrical. connection to the anode.

In the brush shown in Fig. 10 the anode consists of a plurality of anode elements freely suspended within the bristles 22 which are secured directly to the handle 23. The anode elements are suspended on a conducting member 29 which extends upwardly through holes in the base of the brush head and the handle and which is connected to a clamp 25 for securing the electrical connection to the anode. The anode elements, designated 30 in Fig. 10, may be of various forms. For example, the anode elements may be loops of flat or round wire or the like as illustrated in Figs. 11 to 14.

Various types of hair may be used as the bristles of the brush. For example, ordinary hog bristles may be used or camels hair or civet hair may be employed. Other free fibres, such as hemp fibres. are also useful in making up the bristle head of the improved brush of the invention. Civet hair has been found particularly advantageous.

The improved brush of the present invention is of more or less general utility in electroplating conducting surfaces, but it is of special value and application in plating surfaces Which because of bulk or arrangement or attachment to other objects are not readily treated by the customary electroplating bath methods. For example, the improved brush of the invention is useful in the automobile repair shop for replating bumpers, lamps rims, door handles, dash instruments, and radiators and the like, and with the improved brush of the present invention a metallic coating of good physical properties and of good appearance can be deposited upon such parts of an automobile" without removing the parts from the automobile. The improved brush of the present invention is also usefulin the plumbing trade for replating in place faucets and piping and surrounded by the bristles of the bristle head whereby the anode is wholly immersed in plating solution retained by the bristles, and an electrical connection to the anode.

2. An-improved brush for electroplating conducting surfaces, comprising a handle and a bristle head adapted to retain plat.- ing solution, an anode supported flexibly and arranged within and surrounded by the bristles of the bristle head whereby the anode is Wholly immersed in plating solution retained by the bristles, and an electrical connection to the anode.

3. An improved brush for electroplating conducting surfaces, comprising a handle and a bristle head adapted to retain plating solution, an anode arranged within and sur rounded by the bristles of the bristle head whereby the anode is wholly immersed in plating solution retained by the bristles, a pervious web arranged about the bristles and an electrical connection to the anode. I 4. An improved brush for electroplating conducting surfaces, comprising a handle and a bristle head adapted to retain plating solution, an anode of the metal to be plated arranged within and surrounded by the bristles of the bristle head whereby the anode is wholly immersed in plating solution retained by the bristles, and an electrical connection to the anode.

5. An improved brush for electroplating conducting surfaces, comprising a handle and a bristle head composed of civet hair adapted to retain plating solution, an anode arranged within and surrounded by the bristles of the bristle head whereby the anode is wholly immersed in plating solution retained by the bristles, and an electrical connection to the anode.

6. An improved brush for electroplating conducting surfaces, comprising a handle and a bristle head, an anode arranged within and surrounded by the bristles of the head and flexibly supported from the handle, and an electrical connection to the anode.

7. An improved brush for electroplating conducting surfaces, comprising a handle and a bristle head, an anode composed of a plurality of flexible metal wires extending from the handle and a lesser distance than the bristles and arranged within and surrounded by the bristles of the head and supported from the handle, and an electrical connection to the anode.

8. An improved brush for electroplating conducting surfaces, comprising a handle and a bristle head adapted to retain plat ing solution, an anode arranged within and surrounded by the bristles of the bristle head whereby the anode is wholly immersed in plating solution retained by the bristles, and an electrical connection to the anode arranged adjacent the bristle end of the brush.

9. An improved brush for electroplating conducting surfaces, comprising a handle and a bristle head adapted to retain plating solution, a removable anode arranged within and surrounded by the bristles of the bristle head whereby theanode is wholly immersed in plating solution retained by the bristles, and an electrical connection to the anode.

10. An improved brush for electroplating conducting surfaces, comprising a handle and a bristle head adapted to retain plating solution, an anode arranged within and surrounded by the bristles of the bristle head whereby the anode is wholly immersed in plating solution retained by the bristles, a flexible web arranged about the bristles and an electrical connection to the anode.

In testimony whereof I affix. my signature.

FREDERICK CONLIN.

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