US3525681A - Electrolytic device - Google Patents

Description

25, 1910 F. R. RAPIDS 3,525,681

ELECTROLYTIC DEVICE Filed April 21, 1967' United States Patent Office 3,525,681 Patented Aug. 25, 1970 US. Cl. 204-224 3 Claims ABSTRACT OF THE DISCLOSURE A pair of electrically conductive tongs, the free leg portions of which are provided with electrodes enclosed by or carrying absorbent material saturated with an electrolyte of the desired composition. The legs are elongated and are of sufficient resiliency to be spread apart or to be brought together to accommodate therebetween a wide range of diameters of cylindrical articles or thicknesses of planar faced pieces to be plated, or stripped, when the proper electric current is passed through the tongs, electrolyte, and article. The tongs are of such size as to be held in one hand in firm simultaneous engagement with opposite surfaces of the article to be treated while moving the tongs relative to the axis or length of the article. The utility of the device and method resides in the ease with which metals and other electrodepositable substances can be applied locally to, or stripped from, surfaces to facilitate soldering or other processing steps, or to build up worn or low spots, particularly on shafting, collars, sleeves and other cylindrical or planar articles. By making the article the anode, stripping of metal or of metal coatings from the article can be effected.

BACKGROUND OF THE INVENTION The field of the invention is that of metal plating or stripping by the manual operation and control of an electrolytic device.

The prior art includes my own Pat. No. 2,061,592, dated Nov. 24, 1936. The present invention differs from that of my patent in that almost any of the conventional plating baths can be used as the electrolyte and plating is carried out more conveniently in the case of cylindrical articles by application of the plating solution to opposite sides of the article while the latter is being rotated about its own axis.

SUMMARY My invention relates in its preferred form to a portable, manually held electrolytic device, in the form of a pair of tongs of resilient electrically conductive metal, and sleeves of a liquid absorbent fabric enclosing the free end portions of the legs of the tongs. The sleeves are dipped from time to time in the liquid electrolyte, which may be a conventional metal plating bath or stripping bath, in order to keep the sleeves saturated with the electrolyte during the plating or stripping operation.

In place of sleeves, a ball-like mass of absorbent material, saturated with a liquid electrolyte can be held by the tongs and applied to a surface to electrolytically plate or strip metal on or from such surface.

The tongs are of sulficient resiliency that the sleeve enclosed portions can be spread apart or brought together to accommodate a wide range of diameters where cylindrical articles are to be processed, or a wide range of thickness where articles of rectangular cross section are involved.

Cylindrical articles are conveniently mounted for rotation about their own axes, as in a lathe, or the like, and are rotated while the sleeve-enclosed portions of the tongs are manually held in firm contact with the surface of the rotating article and are moved axially thereof over that portion of the article that is to be plated or stripped. An electrical current is passed through a circuit that includes the manually held tongs, the liquid electrolyte with which the..fabric sleeves or other absorbent material are saturated, and the article, itself, so that the article and the tongs, or the electrode portions thereof, constitute electrodes, respectively, of the desired polarity for effecting plating or stripping, as the case may be.

BRIEF DESCRIPTON OF THE DRAWINGS FIG. 1 is a schematic elevational view illustrating the method of mounting and rotating cylindrical articles to be processed by the use of the device and method of my invention;

FIG. 2 is avertical cross-sectional view of a container of electrolyte with the device positioned therein so as to saturate the sleeves of the device with an electrolyte;

FIG. 3 is a side elevational view of my portable device in its associated relationship to a cylindrical article, shown in section, with the electrical circuit shown schematically;

FIG. 4 is a view similar to FIG. 3 with a cylindrical article of much smaller diameter;

FIG. 5 is a broken-away, side elevational view of a length of a cylindrical article, with the electrolytic device, shown in section, in operative engagement with the article;

FIG. 6 is an elevational view of one leg of the tongs with the absorbent fabric sleeve removed to illustrate the electrode;

FIG. 7 is a top plan view of the same portion of the tongs as shown in FIG. 6;

FIG. 8 is an elevational view of a modified form of my invention, with the article undergoing treatment shown in section, and

'FIG. 9 is a fragmentary plan view, partly broken away and in section, illustrating a flat electrical contact being plated by the use of my device and method.

AS SHOWN ON THE DRAWINGS The reference numeral 10 indicates generally the portable and manually operable electrolytic device of my invention. Said device is preferably formed of a pair of tongs having a bight portion 11 and integral legs 12 and 13 extending therefrom. Any bifurcated member having the gripping capability and the electrically conductive properties necessary can be used satisfactorily but a resilient pair of tongs is preferred. An electrically conductive attachment in the form of a U is riveted or otherwise secured to the bight 11 on the outside thereof to provide a connector 15. Said connector 15 includes a short length of rod 16 forming a male portion secured thereto for connection (as by a plug, not shown) to a lead wire 17 and a circuit 18 that includes a source of direct current, such as a battery 19, the article 21 and the switch 20 (FIG. 3). Any suitable connection can be used in place of the connector 15 and prong 16, as for instance, by the use of a conductive clip or by soldering the wire 17 to the device 10. The workpiece, or article 21 is connected in the circuit 13 by closing the switch 20. Said article 21 will then be of opposite polarity to the polarity of the connector 16 and the device 10.

The integral portion of the device 10 that includes the legs 12 and 13 and the bight 11 is preferably formed of a sufficiently resilient strip of metal that the legs 12 and 13 can be spread apart to accommodate a relatively large diameter article, such as the cylindrical shaft portion 21, or can be brought together to engage therebetween a relatively small diameter article, such as a wire of the finest diameter available, or a rod 22 (FIG. 4). The range of diameters or thicknesses of the articles to be accom modated should be from the smallest diameter of wire to 6 inches or more. To permit such a range of spread of the legs 12 and 13, or their contraction, the device 10 is relatively elongated and in its normal state of rest has a relatively small included angle at the bight 11, as for instance an angle of 5 to 20 degrees. During plating or stripping, the operator effects relative surface movement along the length of the wire or rod While firmly establishing contact with the surfaces to be treated.

As best shown in FIGS. 6 and 7, the legs 12 and 13, which are of identical dimensions and contours, are formed of reltively thin sheet metal flanged as at 25 toward their ends to form partial sockets for receiving relatively thicker and heavier bars 26 of suitable composition to form electrodes. Each bar 26 is shown riveted, as at 27, to the inside face of the socket-forming flanged portion 25 of each of the legs, but can be secured in the sockets by a friction fit or by bolts so as to be easily removed and replaced. The electrodes can either be inert to, or corrodible by, the electrolyte.

Sleeves 28 of absorbent fabric material, inert to the electrolyte, enclose the electrodes 26 for a substantial portion of their length to be carried thereby. Each of said sleeves 28 is of a woven or unwoven fabric that is absorbent of liquids, such as the liquid electrolyte that is used in the method of my invention. Cotton or other natural fiber, or synthetic fibers, such as acrylonitrile, can be used, either as woven or unwoven fabrics. Cotton batting and glass wool are examples of unwoven fabrics. Each sleeve 28 is open at one end to permit positioning over the end of an electrode 26, and is closed at the other end, as at 29.

As illustrated in FIG. 2, before the device is to be used, its sleeved ends are dipped into a bath 30 of the composition with which the sleeves 28 are to be saturated. As previously indicated, the bath 30 may be any conventional plating solution, or it can be a solution adapted for use when the device 10 is employed for stripping metal from the surface of the article 21, rather than for electrodepositioning thereon a metal, resin, or other substance capable of being electrodeposited.

In the use of my method for building up, plating or otherwise treating an article, such as the artcle 21, which is of generally circular cross section, the article, if a large one, is mounted upon a shaft 31 that is power driven, as by a belt 32 that drives a pulley 33 on a stub shaft 34 coaxial with and in driving relationship to the shaft 31. Suitable mounting means 35 are provided for the stub shaft 34 and connecting shaft 36. No specific means for mounting and power driving the article 21 are required, a lathe or the like being suflicient for the purpose.

In carrying out the method of my invention, as illustrated in FIG. 1, the device 10, connected in the circuit 18, is manually held and moved lengthwise along the article 21 with the electrolyte-saturated sleeves 28 in firm contact engagement with diametrically opposie portions of the cylindrical surface of the article. The tong-like device 10 can be held at any desired angle, either that shown in FIG. 1, or at right angles to the axis of the article 21, and can be moved slowly in one direction or the other axially of said article during the plating thereof or the stripping of a superficial layer or coating of metal from the surface of the article.

In the modified form of my invention illustrated in FIG. 8, the device 10a, with or without sleeves, as desired, is used, as any pair of tongs would normally be used, to hold a ball-like mass of absorbent material 40 between its pinched-together ends 46 and 47. The absorbent material is, of course, initially saturated with an electrolyte, in the manner indicated in FIG. 2. The article to be treated, indicated by the reference numeral 48 in FIG. 8, may be one having a depression, hollow, or the like, 49, which is to be plated, or stripped. The treatment is carried out by rubbing the absorbent mass 45 over the surface 50 of the depression 49, While using the required type of electrolyte, current, etc., to accomplish the desired effect. Usually the size of the absorbent mass 45 will be sufiiciently large to afford a broad surface of contact, as at C, between the absorbent mass and the surface of the article, or workpiece, 48 to be treated. The free ends 46 and 47 not only hold a portion of the mass 45 pinched therebetween but said free ends are embedded in said absorbent mass so as to prevent direct contact between said free ends and the surface of the workpiece, thereby preventing short circuiting therebetween. Thus, the electrical current to the connector 15 passes through the free end 46 and 47, and through the portion of the absorbent mass 45 enclosing said free ends to the surface 50. There is no direct contact between said surface 50 and said free ends 46 and 47 because whatever the depth and radius of curvature of the depression 49, the surface of which is to be plated or stripped, the absorbent mass 45 by virtue of the pinching together or spreading apart of the free ends 46 and 47 can be brought into and maintained in contact with said surface 50.

As in the case of the sleeved device 10 of FIGS. 1 through 5, the current passes through the pair of end electrodes 26, through the electrolyte with which the absorbent mass 45 is saturated, or wetted, to the surface with which the mass 45 is held in contact. The electrodes 26 and article 48 are of different polarity in an electric circuit similar to that illustrated in FIG. 3. In all methods of my invention an electrolyte is chosen that will wet the surfaces of the electrodes 26 and of the article 21, 22 or 48 that form a part of the plating or stripping surface.

Suitable compositions of electrolyte for use in plating are the following:

Typical solutions for applying metal Formula No. 1: Oz./gal. Copper cyanide 4 Sodium cyanide 6 Rochelle salt 1 Formula No. 2:

Nickel chloride 36 Ammonium chloride 9 Boric acid 4 Typical solution for removing iron Formula No. 3:

Ammonium chloride 8 Sodium chloride l2 Glycerine 8 Typical solution for removing copper and copper alloys Formula No. 4: oz./ gal. Sodium cyanide 10 Sodium carbonate 6 Where desired, the anodes may be of the corrodible type, suitable for introducing into the electrolyte ions the metal to be plated, rather than using the electrolyte to furnish a source of the ions of the metal to be plated, as in Formulas Nos. 1 and 2 above.

In FIG. 9, the reference numeral indicates generally a nonconductive contact holder having an electrical contact 56 arranged in a separate small compartment 57 formed in said device. The contact 56 is a relatively thin, rectangular metal plate that is relatively inaccessible for plating except by the use of tongs 10b of appropriate size and dimension to permit the insertion of their sleeved ends 59 into the compartment 57 and also to permit relative movement between said sleeved ends and the opposite surfaces 60 and 61 of the contact 56 engaged thereby. In this manner and by the use of my tongs, the surfaces 60 and 61 can be plated satisfactorily with a highly conductive metal such as silver.

One of the advantages of my method is that it speeds up the plating or stripping because acting simultaneously upon opposite sides or surfaces of the article. Another advantage is that by the use of the flexible absorbent sleeves 28 or masses 45, the electrolyte that tends to be forced out under the pressure of the contact between the absorbent material and the surface undergoing treatment is free to migrate to one side or the other of such area of contact and then to migrate back again as the area of contact is changed. The absorbent material, for this reason, does not tend to be exhausted of electrolyte so quickly as would be the case if the same area of contact between sleeve and article were maintained for any extended period of time instead of the areas being constantly changed in the processing operation.

It will be understood that modifications and variations may be eifected without departing from the scope of the novel concepts of the present invention.

I claim:

1. An electrolytic device for applying an electric current through an electrolyte to a metal surface, comprising a pair of tongs including an integral bight portion and a pair of legs spreadable with respect to each other,

said legs having free ends constituted by electrodes forming electrical and mechanical extensions of said legs,

a liquid electrolyte absorptive material carried by said electrodes and enclosing said free ends thereof so as to maintain direct contact of said absorptive material with said metal surface during use of said electrolytic device, and

electric conductive means associated with said tongs for passing an electric current through said electrodes and through electrolyte absorbently held by said material directly to said metal surface.

2. A device as defined by claim 1 wherein said material comprises sleeves of an inert absorptive fabric enclosing said electrodes.

3. A device as defined by claim 2, wherein said pair of tongs is of such length and resiliency that said legs can be brought together and be spread apart to accommodate therebetween the finest diameter wire and workpieces of 6 inches and more in thickness to bring said sleeves in contact with opposed surface portions of wire and workpieces.

References Cited UNITED STATES PATENTS 1,545,942 7/1925 Conlin 204224 2,463,711 3/1949 Nagle 204--224 3,259,556 7/ 1966 De Nault 204-244 FOREIGN PATENTS 18,643 1899 Great Britain.

JOHN H. MACK, Primary Examiner 0 T. TUFARIELLO, Assistant Examiner

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