Brush for electrolytic use and electrodes therefor

Application filed April 18,

This invention relates to brushes for electrolytic use, such for example as used for electroplating or electrocleaning, and to electrodes therefor. “ ⁵ The invention provides improved devices of the character referred to, the devices being readily adaptable for substitution and replacement of electrodes, and having simple means for retaining the replaceable elec¹⁰ trodes. The devices further embody features adapted for assisting in the retention of liquid in the vicinity of the electrode.

The invention further provides improved devices of the character referred to, comprising an electrode, and particularly a soluble anode, having a relatively large surface area, whereby the electrode area may be as large as or larger than the effective plating area of the brush in contact with the surface ²⁰ to be plated j and which may also cause a minimum displacement or distortion of bristles in the head of .bristles.

The invention further provides improved devices of the character referred to wherein ²⁵ a large area of contact is provided between the electrode, and the filaments or films of electrolyte held between the bristles, and wherein a large and relatively uniform flow of current through the brush is permitted ³⁰ during manipulation.

The invention further provides an improved electrode for brushes of the character described.

Other features of improvement will be ³⁵ pointed out in the particular (description which follows.

Several embodiments of the invention are illustrated in the accompanying drawing wherein:— ⁴⁰ Figure 1 is a vertical sectional view of one embodiment of brush for electrolytic use.

Figs. 2 and 3 are respectively a top-plan view and a sectional view on line II—II, Fig. 1, of the electrode shown in Fig. 1.

⁴⁵ Figs. 4 and 5 are respectively a side elevation, and a top plan view of another embodiment of electrode.

Figs. 6 and 7 are respectively a side elevation, and a top plan view of another em⁶⁰ bodiment of electrode.

, 1931. Serial No. 531,149.

Figs. 8 and 9 are respectively a side elevation and a top plan view of still another embodiment of electrode.

Referring to said drawing, numeral 10 designates the brush as a whole, comprising a 55 head of filaments or bristles 12, and preferably also a handle 14, the head of bristles being secured to the brush in any suitable manner, as by means of a ferrule 16 clamped around a lower extension 18 of the handle. A 60 filler 20 may be provided around the handle above the head of bristles, as usual. The bristles may be of any suitable material to best withstand the action of the electrolyte, but are ordinarily hog bristles. 65

Numeral 24 designates an electrode support which is preferably a rod of conducting material, extending through a longitudinal space 26 in the handle, one end projecting into the core or middle of the bristles- 70 head and the other end preferably projecting from the upper end of the handle and having means 28, as a clamping nut having a screw-threaded engagement therewith, for fastening an electrical conducting wire 75 thereto. The rod 24 may be made hollow and provided with outlets, within the head of bristles, where it is desired to furnish solution in this way to the head of bristles, as indicated at 60. The electrode support 80 24 is preferably adjustable longitudinally in the head of bristles, suitable means, as a binding screw 30 adapted to press at its end thereon, being provided for holding the electrode support in different positions of longi- 85 tudmal adjustment in the head of bristles.

Numeral 35 designates the electrode which is carried by the electrode support 24. The electrode 35 is preferably detachably connected to the support 24 to permit of substi- 80 tution or replacement, by a . suitable connection 38. The connection 38 is preferably of the type in which connection and disconnection is made by a rotary movement of the electrode, being formed for example by 85 threads on the end 39 of support 24 and reciprocal threads in a socket 40 in the electrode. The threaded end 39 of the rod 24 forms an electric terminal to which the electrode 35 is attached. 100

1,808,000 versely of the bristles. The horizontal grooves permit of an accumulation of electrolyte therein and prevents a rapid flow of electrolyte down over the electrode. .

The surface. areas on the'sides of the electtodes shown in the several embodiments, these being the practically important part of the electrode as regards transmission of current between electrode and solution, is approximately one-quarter to one-half _ greater ⁷⁵than the area of a solid figure having the same space-volume. With a brush such as illustrated, the effective plating area is about two square inches. The surface area of the electrodes illustrated (area of the sides) is from approximately two and one-half to three square inches. There is a further advantage' in the electrode having the area in- creased by the lateral projections, according to 'this invention, inasmuch- as the bristles ⁸⁵are-enabled to approach the axis of the brush and to substantially fill the area at the free ends of the bristles in the head, ’ whereas- a solid electrode having the space-volume of the present electrodes would prevent the bristles approaching the axis of the brush at the ends thereof and leave a central space in the head of bristles, at the free ends of the bristles. '

The electrodes 35 with the lateral projection 44 inay have a variety of forms, some of which are shown in the several embodiments illustrated. The projections 44 preferably extend longitudinally of the electrode, and preferably taper toward the axis of the electrode at its lower end, whereby the depth of penetration of the projections into the bristles at said lower end of the electrode is reduced, or eliminated as shown, .whereby danger of the projections making • contact with the surface being plated (or cleaned) is avoided.

Perforations 70 running through the projections 44 and/or through the body may be provided, to facilitate the supply of electrolyte around the electrode. These perforations act as pockets and also as conduits through which electrolytic solution may run • from the side of the brush which is full of _ngelectrolytic solution to the side which is lean.

Vertical or upwardly inclined vents or passages 71 may also be provided, and these may open into the perforations 70. These vents or passages 71 provide a means for ₁₂o solution to run back and forth between the sides and top of the electrode, according to the pressure on the bristles due to the manipulation of the brush, and also afford a vent for gas. ¹²⁵

Means 80 may also be provided for venting gas from the space 81 above the electrode⁵. This means is conveniently a vertical channel 83 in the handle 10 with a lateral ς branch 84 to the atmosphere. ¹³⁹

The electrode is provided with means for largely'increasing- the surface area within a relatively small space-volume, and also with means for coacting with the head^Joi bristles 5 to prevent' detachment of the electrode o5 when formed as a detachable electrode, from its support. The means for preventing detachment of the electrode 35, is preferably a lateral projection 44. Furthermore, by in10 creasing the number and length of these projections 44 the surface area of the electrode compared with' its space volume is greatly enlarged, and the form of embodiment comprising a number of lateral projections is 15 preferred as it combines the several functions above set forth, as well as the function of providing means for receiving or confining tufts of the bristles in such a way as to prevent lateral displacement of the bristles ²⁰ during, manipulation of the brush and the forcing through and consequent exposure, of the electrode during use, and the consequent liability of short circuits and arcing. Other means of increasing the surface area of the ²⁵ electrode in relation to its space volume, and in fact separate means for performing the functions above stated may be adopted in connection with the electrode. As will be readily understood, the lateral projections 30 44 _are transverse to the bristles,· and extend into the mass of bristles, and this interengagement of the bristles with the projections 44 acts to prevent turning of the electrode 35, and its detachment from the detachable con³⁶ nection 38 between it and its support 24.

However, by parting the bristles so as to spread and expose the electrode 35, the said electrode may be rotated and readily detached and another substituted in its place. By al4® lowing the bristles to re-assume their natural position, the new electrode is again locked against turning by the bristles pressing in -against the electrode and on each side of the projections. .

The electrodes are soluble or insoluble, and¹ of material suitable for electrodes. The soluble electrodes are of metal (or alloys), and when used as an anode, the large area above referred to provides a large surface ⁶⁰ for the metal to enter the solution, the metal usually being chosen to. correspond to the metal to be deposited. .

In using the brush, the pressure by which it is applied, acts to squeeze the electrolyte between the bristles, particularly on the side facing the direction in which the brush is drawn over the surface being electroplated (or electrocleaned) and in order to prevent a paucity of the solution around the elec⁶⁰ trode and between the electrode and the bristles, means 50 forming pockets or channels for receiving solution when the bristles are pressed, are provided. These pockets 50 are conveniently formed as grooves which run ⁹⁵ horizontally around the electrode and trans1,908,222 3

Experience in electroplating with brushes around said body, said electrode having holding an electroplating solution, shows channels therein for liquid.

that difficulty was heretofore experienced In witness whereof, I have hereunto in obtaining thick deposits, and in obtaining signed my name.

⁵ a high current density, at the cathode sur- FREDERICK CONT,TN, 70 face. By the present invention the conditions for larger current densities and thicker platings are materially bettered and improved results obtained. _o¹⁰ The invention may receive other embodi- 76 ments than those herein specifically illustrated and described.