US3420766A - Automatic electroplating and washing apparatus - Google Patents

Description

1969 I. MICHELSON 3,

AUTOMATIC ELECTROPLATING AND WASHING APPARATUS Sheet of 2 Filed March 10, 1965 IRVING L. MICHELSON INVENTOR.

ATTORNE Jan. 7, 1969 MICHELSONY I 3,420,766

AUTOMATIC ELECTROPLATING AND WASHING APPARATUS Filed March 10, 1965 IRVING L. MICHELSON I NVENTOR.

BY 4,]. g; ATTORN Y United States Patent 7 Claims ABSTRACT OF THE DISCLOSURE A vibratory electroplating apparatus having electrodes disposed in the vibrating channel so that the articles passing up the channel are electroplated while traveling.

This invention relates to apparatus for electroplating articles. More specifically, the invention pertains to an electroplating apparatus wherein the articles being electroplated are moved along a channel by vibration and against gravity through an electroplating solution.

In the past, many methods have been employed for continuous electroplating of articles. One typical method is described in US. Patent 2,164,170 issued July 4, 1939. The invention described in that patent feeds the parts by gravity force through a downwardly slanting trough immersedin the electroplating solution. The force of gravity, aided by to and fro oscillation of the trough, causes the parts to pass through the plating solution onto a conveyor belt. The belt then carries the plated parts into a final wash solution. Since the parts are carried through the electroplating solution by the force of gravity, they are naturally maintained in close, continuous, and intimate contact with the bottom of the trough. As a consequence, the resultant smooth flow makes the maintenance of continuous electrical contact between the parts and the electrodes during electroplating very easy. However, the equipment required for -a gravity feed system of the type shown in the above patent is very complex. Accordingly, the art has not made wide use of such equipment; instead, batch plating rather than continuous plating has become much more prevalent in the industry.

Although vibratory feeding mechanisms in general have become well-known recently'( see for example US. Patent 3,147,841, issued Sept. 8, 1964), they have n-ot been employed for electroplating. It was heretofore expected that the, vibration of the parts caused by such a feeding system would result in continual interruption of electrical contact, "between the parts and the electroplating electrodes-This continual interruption of contact was expected to result in uneven plating, thus destroying the etfectiveness of the resulting electroplating apparatus. Contrary to these expectations, however, the invention to be described below makes use of a vibratory mechanism to feed parts to be electroplated along a channel against the force of gravity; yet the system results in even plating of the parts.

Briefly, the apparatus of the subject invention comprises: a channel adapted to hold an electroplating solution and the conductive articles to be electroplated; a means for vibrating this channel to cause the articles to move against gravity substantially in a single direction along the channel; an electrode means within the channel for making continual electrical contact with the articles as they pass along the channel; and a second electrode disposed within the solution, these electrodes passing a current through the solution and the articles, thereby causing the articles to be electroplated. The electroplating apparatus of this invention is much simpler than prior art apparatus, such as that shown in the US. Patent 2,164,710, discussed above.

Further advantages and details of the invention will ice become apparent from the more detailed description which follows, making reference to the drawing in which:

FIG. 1 is a pictoral view of the apparatus of the subject invention;

FIG. 2 is a cross-sectional elevation view taken through the section 22 of FIG. 1; and

FIGS. 3-7 show alternative embodiments of the invention, each using a different technique for making a continual electrical contact with the articles being electroplated.

Referring to FIG. 1, the parts 10 are first placed in the channel 11 of 'bowl 12. Bowl 12 is vibrated in a conventional manner, such as is described in US. Patent 3,147,841. Such vibration is generally caused electro-. magnetically. The vibratory action utilizes the sudden release of electrical energy stored in a capacitor to cause a heavy transient current to flow into an actuating coil, thus subjecting the entire bowl 12, including channel 11, to an abrupt mechanical shock. The amount of such shock is regulated in bowl 12 by controller 13. Vibration frequencies of at least 60 c.p.s. are normally used. Alternatively, instead of delivering a mechanical jolt to the feeder vibrating mechanism, a timer mechanism may be used which cuts on and off at predetermined intervals, the electrical energy causing the vibration. This sudden interruption of the energy causing the vibration serves to jolt the bowl 12 and the parts 10, which aids in breaking up jams and moving the parts through channel 11.

Bowl 12 is filled with an electroplating solution 14. Such solutions are well-known in the art, and contain a suitable electrolyte containing ions of the element to be deposited on the articles 10 during the electroplating process. For example, if copper were to be deposited, CuSO, could be used as the electrolyte solution. In some instances, it is desirable that the electroplating solution 14 be heated. To accomplish this, the apparatus of the invention has a heating cartridge 15. Cartridge 15 is merely a conventional immersion heater which is connected through line cord 15A to a suitable A-C power supply. I

A pair of electrodes are used to accomplish the electroplating. The first electrode which is conductive band 17 supported by support tube 16 may either be the cathode or the anode, is placed in the center of how] 12 containing solution 14. A suitable power supply is connected to the electrode 17A in order to achieve the desired polarity. For an anode, of course, a positive power supply terminal is connected; for a cathode, a negative power supply terminal is connected. This connection is made to band 17 attached to the lower portion of support tube 16 which is immersed within solution 14. Support tube 16 and heater 15 are together supported by arm 18 which in turn is supported by a vertical post 18a.

The parts 10 to be plated are moved by the vibratory action of bowl 12 upwardly against gravity along channel 11. In the illustrated embodiment, these parts move in a counter-clockwise direction (although the opposite may easily be used). The length of the channel 11 may vary, and is determined according to the length of time it is desirable to have the parts within the plating solution. This time can also be regulated by adjusting the amount of vibration. This is done by regulating vibration control 13. At the end of channel 11 is a gating mechanism 19. This gating mechanism includes solenoid 20 and gate lever 21. Gate lever 21 is shown by dotted lines 22 in the position used to release the parts from channel 11. Otherwise the parts are held within the channel. Gate mechanism 21 may be actuated by a timer or manually, depending on the type of plating operation being carried out. When gate 21 is in position 22, parts 10 will emerge from track 11 through end portion 23. In the illustrated embodiment, these parts then fall into a second vibratory bowl 24 having a channel 25. Bowl 24 contains a wash solution. The method of transportation of the parts 10 through bowl 2.4 is substantially the same as that used in the plating bowl 12. The completed parts pass out the end 26 of channel 25 and into a convenient receptacle 27. The amount of vibration of bowl 24 is controlled by vibration controller 28.

An important aspect of the invention is the means used to make continual electrical contact with the articles 10 as they pass along channel 11. In the embodiment illustrated in FIG. 1 (and shown in cross-section in FIG. 2) this contact is made through electrode 29. This electrode, which may be an anode or a cathode, is a wire placed along the exterior perimeter of the channel 11. The centrifugal force of the parts traveling around channel 11 causes them to hug its exterior perimeter, thereby maintaining continual contact with electrode 29. Thus uniform plating of the parts is assured. The remainder of the interior of channel 11 is coated with an insulating layer 30, shown in FIG. 2. It is impractical to use the entire channel 11 as the electrode because in normal operation, the electrode itself becomes plated along with the articles 10. If the entire track were used as the electrode, a substantial amount of the electroplating solution will be spent to plate the tract; this represents an appreciable waste of solution. Accordingly, electrode 29 is of relatively small external area compared to the channel, and does not therefore waste any substantial amount of the electroplating solution as it becomes plated. Moreover, it represents a smaller area to be cleaned.

From the above description, it is apparent that the apparatus of this invention uses a single vibrating mechanism both to feed the parts along the channel, and to agitate the parts and the electroplating solution to obtain uniform plating. Whereas it was expected that agitation of the parts, resulting continuous making and breaking of electrical contact with the electrode, would cause uneven plating, it was unexpectedly discovered that the very opposite wes true. The high degree of agitation of the parts and the solution results in a very even electroplated coating on the parts. It is apparent that the apparatus of this invention provides a completely automated way of electroplating, feeding parts, and agitating the parts in a continuous operation. The system preferably employs a continuous recirculating and filtering apparatus to clean the plating solution. Such apparatus is well known in the art.

FIGS. 37 represent alternative embodiments for making continual electrical contact with the parts being plated, In the embodiment shown in FIG. 3, channel 11 is fabricated fnom. an insulating material, such as Teflon, polyethylene, epoxy, ceramic, porcelain, polypropylene, glass, polyvinylchloride, or the like. At regularly spaced intervals along the bottom of the tract, a plurality of raised metallic terminals 31, which serve as sub-electrodes, are rigidly attached. Electrical contact is made between subelectrodes 31 by wires 32. These are connected together andto the power supply to form one electrode of the plating apparatus.

In the embodiment of FIG. 4, sub-electrodes 31 are placed along the outer edge of channel 11 rather than on the bottom. Due to the centrifugal force on the parts as they spiral around track 11, they make continual contact with sub-electrodes 31. In this embodiment, channel 11 is fabricated from conductive material, but is coated on the interior surface with an insulating layer 30. Sub-electrodes 31 make contact with and are connected together by the conductive portion of channel 11. Screw 32a is adapted to hold the electrical connection from the power supply to the sub-electrodes 31.

FIG. is very similar to the embodiment shown in FIG. 1, except that a narrow conductive area, i.e., a metallic ribbon 33 is used along the outer edge of channel 4 11, rather than a wire as shown in FIGS. 1 and 2. Such a ribbon provides additional area for making contact with the parts being plated. Electrical connection to ribbon 33 is accomplished through screw 32a as described above.

FIG. 6 shows still another means of {making contact wherein moving sub-electrodes 34 are interspersed among the parts being plated. Here again channel 11 is insulating. These moving contacts pass along channel 11 intermingled with the parts being plated. Wires 35 are used to make electrical connection to each of the sub-electrodes 34. All of these wires are connected to a common wire 36, which serves to connect them as a single electrode of the plating apparatus. The number of sub-electrodes 34 which are required depends upon the size and density of the parts being plated. It is apparent that each individual part need not be contacted by an electrode 34; since the parts are metal, they make contact with each other during the plating operation. Accordingly, it is only necessary to make direct sub-electrode contact with random interspersed members of the group of parts, such number being determined by one skilled in the art. Of course, it would be possible to make each sub-electrode 34 doughnut-shaped so as to actually hold a part (or more than one part) being electroplated. It'is important to avoid leaving unplated spots on the part when it was covered by the sub-electrode 34.

Finally, the embodiment in FIG. 7 shows a channel 11 fabricated of conductive material, but which is insulated with an insulating layer 37 at all places except a narrow conductive area 38. This unco'ated strip 38 makes electrical contact with the parts during their passage through otherwise insulated channel 11. The insulating material 37 limits the electrode area to avoid unnecessary use of electrolyte solution, as was discussed above.

It will be apparent to one skilled in ,the art that many modifications may be made in the specific embodiments of the invention described above, not only in means for making electrode contact with the parts, but in other details as well, without departing from the spirit and scope of the invention. Accordingly, it is the intention that the scope of this invention be defined only as recited in the claims which follow.

What is claimed is:

1. Apparatus for electroplating conductive article which comprises:

a helical sloping channel adapted to hold an electroplating solution and the conductive articles to be electroplated;

a means for vibrating said channel tocause said articles to move against gravity substantially in a single direction along said channel;

an electrode means disposed adjacent the outer edge of said channel for making continual electrical contact with said articles as they pass along said channel; and

a second electrode disposed within said solution, said electrodes passing a current through said solution and said articles, thereby causing said articles to be electroplated.

2. Apparatus for electroplating conductive articles which comprises:

a helical sloping channel adapted to hold an electroplating solution and the conductive articles to be electroplated;

a means for vibrating said channel to cause said articles to move against gravity substantially in a single direction along said channel;

an electrode means rigidly attached to an inner surface of said channel adjacent the outer edge thereof within said solution for making continual electrical contact with said articles as they pass along said channel; and

a second electrode disposed within said solution, said electrodes passing a current through said solution and said articles, thereby causing said articles to be electroplated.

3. Apparatus for electroplating conductive articles which comprises:

a helical sloping channel adapted to hold an electroplating solution and conductive articles to be electroplated;

a means for vibrating said channel to cause said articles to move against gravity substantially in a single direction along said channel;

an insulating layer coating the interior surface of said channel;

a plurality of connected electrodes within said channel adjacent said insulating layer and located near the outer edge of said channel for making continual electrical contact with said articles as they pass along said channel; and

a second electrode disposed within said solution, said electrodes passing a current through said solution and said articles, thereby causing said articles to be electroplated.

4. The apparatus of claim 3 wherein the entire channel is fabricated of insulating material.

5. The apparatus of claim 3 further characterized by said channel being electrically conductive and said plurality of electrodes being in contact -With and electrically connected to each other through said channel.

6. Apparatus for electroplating conductive articles which comprises:

a helical sloping channel adapted to hold an electroplating solution and the conductive articles to be electroplated;

a means for vibrating said channel to cause said articles to move against gravity substantially in a single direction along said channel;

an electrode means comprising a narrow conductive area on the interior of said channel at its outer edge along its length for making continual electrical contact with said articles as they pass along said channel; and

a second electrode disposed within said solution, said electrodes passing a current through said solution and said articles, thereby causing said articles to be electroplated.

7. Apparatus for electroplating conductive articles which comprises:

a channel adapted to hold an electroplating solution and the conductive articles to be electroplated;

a means for vibrating said channel to cause said articles to move against gravity substantially in a single direction along said channel;

a plurality of moving electrode means within said channel and interspersed within said articles for making continual electrical contact with at least some of said articles as they pass along said channel; and

a second electrode disposed within said solution, said electrodes passing a current through said solution and said articles, thereby causing said articles to be electroplated.

References Cited UNITED STATES PATENTS 2,911,345 11/1959 Swenson 204201 3,209,900 10/ 1965 Prutton 19822O 3,275,542 9/ 1966 Couture 204--222 FOREIGN PATENTS 704,128 2/ 1931 France.

HOWARD S. WILLIAMS, Primary Examiner.

W. VAN SISE, Assistant Examiner.

US. Cl. X.R. 204--222, 223, 297

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