US2519945A

US2519945A - Electroplating apparatus

Info

Publication number: US2519945A
Application number: US643326A
Authority: US
Inventors: Karl A W Twele; Albert D Canner
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1946-01-25
Filing date: 1946-01-25
Publication date: 1950-08-22
Anticipated expiration: 1967-08-22

Description

g- 1950 K. A. w. TWELE ETAL 2,519,945

I ELECTROPLATING APPARATUS Filed Jan. 25, 1946 2 Sheets-Sheet 1 Inventors: KaF|A.W.TWe|e, Albert D. Cannen Their Attorney.

g 1950 K. A. w. TWELE ET AL 5 ELECTROPLATING APPARATUS Filed Jan. 25, 1946 2 Sheets-Sheet 2 In vento rs: I Kan-lAWTwele, Albert D.Canner-,

i b 'W l Their Atborn eg.

Patented Aug. 22, 1 950 ELECTROPLATING APPARATUS Karl A. W. Twele, Philadelphia, and Albert D. Canner, Upper Darby, Ea, assignors to General Electric Company, a corporation of New York Application January 25, 1946, Serial N 0. 643,326

Glaiins.

Our invention relates to improvements in electroplating apparatus and more particularly to improvements in apparatus for rapidly plating a portion of a work piece.

It is becoming more and more the practice to have silver contact surfaces on electric current conductors such as bus bars, switch blades and studs, and the like. In order not to waste silver, it is customary to mask the piece to be plated by some suitable coating, leaving bare only the portion on which the silver surface is desired. The piece, or at least the part thereof containing the portion which is to be plated, is then immersed in a tank containing a suitable plating bath for a time suificient to produce the desired thickness of plating. The plating time, of course, depends on the thickness of the metal deposit desired for the contact portion. The piece is then taken from the bath, drained and rinsed, and the masking removed. This process is slow because of the time required to apply, dry and remove the masking coating and the slowness of metal deposit due to the relatively low velocity of electrolyte circulation. Moreover, the masking feature, principally a manual operation, is costly.

. An object of our invention is to provide improved apparatus for electroplating continuously with a minimum waste of electrolyte and without masking coatings. vention is to provide improved electroplating apparatus utilizing the advantages of high velocity of electrolyte flow and high plating current densities. Still another object of our invention is to provide improved electroplating apparatus which functions substantially automatically to control the plating, draining and rinsing operations and which is practically foolproof. A further object of our invention is to provide improved electroplating apparatus embodying the maximum of safety to the operator as well as to the apparatus. A still further object of our invention is to provide improved apparatus for electroplating without using pumps which are subject to corrosion and other damage by the electrolyte. These and other objects of our invention will appear in more detail hereinafter.

In accordance with our invention, we provide improved electroplating apparatus wherein a plating head is used to mask only the portion of the work piece to be plated and wherein electrolyte is supplied to the plating head at high velocities under pneumatic pressure and plating current at high densities is used. Also in accordance with our invention, the plating head is Another object of our insupplied with a rinsing liquid after a time sufiicient to drain the electrolyte, and the steps of plating, draining and rinsing automatically proceed in the correct cyclic order with the preset times necessar for each. Again in accordance with our invention, we provide an arrangement for so automatically and continuously circulating electrolyte from a reservoir to two tanks and from either tank pneumatically to the plating head and return to the reservoir that one tank is being filled from the reservoir while the other tank is supplying electrolyte under air pressure to the work piece. Further in accordance with our invention, the plating head comprises relatively movable members suitably arranged to engage the work piece and to mask the portion thereof to be plated and pneumatically operated to the masking position from which the members cannot inadvertently be released as long as there is air pressure tending to cause flow of electrolyte and also while rinsing liquid is flowing to the work piece. Still further in accordance with our invention, we provide an arrangement for quickly running through the plating, draining and rinsing cycle or whatever portion thereof is left in case of an emergency requiring, for example, the release of the plating head. Also in accordance with our invention, we provide improved plating heads for plating areas or one or simultaneously on both sides of a flat piece and for plating curved surfaces either internally or externally.

Our invention will be better understood from the following description when considered in connection with the accompanying two sheets of drawings, and its scope will be pointed out in the appended claims.

In the accompanying two sheets of drawings, Fig. 1 illustrates schematically, partly in diagram and partly in perspective, electroplating apparatus embodying our invention; Fig. 2 is an enlarged perspective view of the plating head shown in Fig. 1 with parts broken away to illustrate the internal structure; Fig. 3 is a part sectional illustration of the plating head shown in Fig. 2, the section being taken substantially at right angles to the longitudinal axis of the work piece looking from right to left as viewed in Fig. 2; Fig. 4 is a part sectional elevation of a modification of the plating head shown in Figs. 1, 2 and 3; and Fig. 5 is a vertical sectional elevation of a plating head for use in plating the convex contact portions of contact studs.

In the embodiment of our invention shown in Fig. 1, we have illustrated an arrangement for plating, on one side or or both sides simultanee ously of a work piece I and around a hole 2 therein, a flat annulus 3 of silver. As shown, the work piece is a flat conductor which may be a copper bus bar, for example. For convenience in operating, the work piece I is so movably supported on a table comprising rollers 4 as to lie between the relatively movable members 5 and 6 of a plating head, shown in more detail in Figs. 2 and 3. In accordance with our invention, the members 5 and 6 are so constructed and arranged as to be actuated to engage the work piece I and mask the portion thereof to be plated. Thus, in this embodiment of the plating head, the lower member 5 is rigidly mounted on a suitable support, not shown, and the upper member 6 is arranged to be actuated by suitable pneumatic means comprising a cylinder 1 supported by brackets 8, shown in part in Fig. 2. Within the cylinder 1 is a piston 9 which is rigidly connected to the upper plating head member 6 by a piston rod I6. Through suitable means such as a fourway air control valve ACV and lower and upper pipes II and I2, respectively, air under pressure from a suitable source, not shown, is admitted to the bottom of the cylinder 1 to raise the upper platin head member 6 and to exhaust the air above the piston 9, and to the top of the cylinder I to lower the upper plating head member 6 and maintain it in the plating position and to exhaust the air below the piston 9. For safety features, hereinafter described, the air pipe I2 to the top of the cylinder 1 is provided with an air pressure switch APS whose contacts are closed only when the air pressure in the pipe I2 is above a predetermined value.

Referring now more particularly to Figs. 2 and 3 which illustrate the plating head members 5 and 6 in the plating position against the work piece I, it will be observed that the body of the lower plating head member 5 is suitably ported for admission of liquids such as electrolyte and water through an inlet pipe I3 and discharge through a downwardly extending outlet pipe I4. In order to insure better circulation of electrolyte and rinsing liquid against the work piece, the inlet pilpe I3 is so arranged as to discharge liquids tangentially to the exterior surface of a suitably shaped diverter and discharge element I5. As shown, this element, which is seated in a recess in the body portion of the member 5, has a generally conical exterior surface. With this arrangement, :a swirling action of the electrolyte and rinsing liquid is effected, as indicated by the arrows I6. Likewise, the plating head 6 is suitably ported for admission of liquids through an inlet pipe II, discharge being by way of the hole in the work piece and the opening in the discharge element I5. As in the case of the lower plating head member 5, a. swirling actionof introduced liquids is effected, as indicated by the arrows I8, by a tangential discharge against a diverter element I9 seated in a recess in the body portion of the upper plating head member 6 axially in line with the diverter element I5 in the lower plating head member 5. As shown, the shape of the diverter element I9 is substantially conical with a generally spherical end.

For masking the portion of the work piece I to be plated and also preventing escape of electrol te and rinsing liquid, each of the plating head members 5 and 6 is provided with a recessed portion in which are seated a cushioning gasket 20, a sealing gasket 2I and, between these, a supporting plate 22, the function of which is to support the sealing gasket 2I when it is necessary to change the sealing gasket for masking a smaller area on the work piece. The gaskets 20 and 2| are of suitable resilient material such as rubber, and the supporting plate is metallic and may be steel. For better sealing and locking action between the supporting plate 22 and the gaskets 20 and 2I, the plate may be provided with annular raised ridges 23. For holding the gaskets 20 and 2I and the supporting plate 22 in place in the respective plating head member, we provide a flanged retainer collar 24 secured to the respective member by suitable means such as screws 25. In case it is desired to plate only one side of the work piece I, then as shown in Fig. 4 the upper sealing gasket 2I is replaced by a sealing plug 2 I having no central opening. With this arrangement, the electrolyte is prevented from touching the upper face of the work piece. In order quickly to drain the plating heads 5 and 6 after the flow of electrolyte and rinsing liquid has been stopped, suitable means such as vent valves 26 are provided.

Plating current is supplied to thedplating head members 5 and 6 from a suitable source of direct current, indicated simply by plus and minus signs, and controlled through an electromagnetically actuated plating current switch PCS. From the upper plating head member 6, plating current is conducted to the work piece I by way of electrodes 21' whichare so resiliently supported on the member 6 as firmly to engage the work piece I when the members 5 and 6 are in the masking position. Thus, as shown, the electrodes 21 are mounted in housings 2B of suitable insulating material carried on arms 29 of the upper plating head member 6 and are biased downward by springs 30. It will be observed that in order to avoid a short circuit of the plating current circuit when the plating heads are in the masking position, the sealing gaskets 2I and the sealing plug 2 I should be of insulating material.

For aligning the work piece I relatively to the plating head members 5 and 6, we provide a. locator 3I which is automatically swung into position over the work piece during the final portion of the upward movement of the upper plating head member 6 and is quickly swung out of the way of this member early in the downward movement thereof. For this purpose, the locator 3| is mounted on an arm 32 which is resiliently coupled to a shaft 33, pivotally supported on a bracket 34, and is arranged to be turned approximately into position over the work piece I near the end of the upward movement of the plating head member 6 and vice versa. For this purpose, the shaft 33, as shown in Fig. 2, is square with an approximate 90 twist at its upper end and an actuator 35, provided with a square hole to register the shaft 33, is arranged to partake of the movement of the plating head member 6. In order to permit overtravel of the shaft 33, the arm 32 is provided with a sleeve 36 which is positioned between the lower shaft bearing 31 and a collar 38 secured to the shaft, and this sleeve is resiliently coupled to the shaft by a torsion spring 39 having one end secured to the collar 38 and the other end positioned in a slot in the sleeve 36. For definitely positioning the locator 3I relatively to the vertical axis or center line of the plating head members 5 and 6, a stop 4'0 on the bracket 34 is arranged to be engaged by an adjustably positioned lug M on the arm 32. In order to compensate for different thicknesses of-work piece, the locator 3| -is yieldinglysusasi e-is pended from the-arm 32 by suitable resilient means such as springs 42. For smooth engagement with the work piece, the ends of the locator are bent upwardly as shown. For definitely locating the work piece, the locator 3| is provided with a hole 43 with which the hole in the work piece is to be registered.

longitudinally the work piece is centered by moving the piece on its table rollers To prevent scuffing the lower sealing gasket 2| during this process, we provide a resiliently supported roller 64 which is mounted on the base of the lower plating head member 5. This roller keeps the work piece clear of the lower sealing gasket II and yet allows the necessary downward movement of the work piece when the upper plating head member 6 is brought into the masking position. For laterally aligning the work piece, we provide suitable means such as a parallel motion mechanism which, as shown in Fig. l, is arranged to move the work piece from the back of the machine to the front. Thus, as shown, this paral-lel motion mechanism comprises a plurality of rollers 45 against which the edge of the work piece i abuts. These rollers are supported on angles 48 which are arranged to be moved transversely of the work supporting table without change in direction. For this purpose, we provide a plurality of actuating shafts 41, only two of which are shown in Fig. 1. These shafts are supported in stationary bearings 33 and are connected to the angles 46 by cranks 49 which are rigid on the shafts and pivotally connected to the angles. For turning the shafts ll simultaneously, We provide an actuator bar 56 which is connected to all of the shafts by cranks i and 5 2 which are rigid on the shafts and pivotally connected to the actuator bar. For moving the actuator bar, one of the cranks 52 is a bell crank, the arm 52' of which carries a swivel nut 53 for engagement by a threaded operating shaft 54. This shaft is supported at its outer end against longitudinal movement in a swivel bearing 55 and is provided with an operating crank. 56.

For supplying electrolyte to the plating head continuously during the plating operation, we provide a reservoir ER for electrolyte and two suitable, preferably metallic, tanks ETI and ETZ which are adapted to be supplied with electrolyte from the reservoir ER and with air under pressure thereby avoiding the use of pumps which would be subject to corrosion and other difficulties. Flow of electrolyte from the reservoir ER is by way of a manually controlled electrolyte valve EVI, a pipe 5'! and. an inlet check valve ICI to the tank ETI and by way of a manually controlled electrolyte valve EV2, a pipe 58 and an inlet check valve 102 to the tank ETZ. The check valves ICE and I02 are to prevent flow of electrolyte from their respective tanks to the reservoir when the tanks are under air pressure. For effecting a flow of electrolye from either of the tanks ETI or ETZ to the plating head and thence to the reservoir ER, we provide valve means operative'in dependence on the levels of the electrolyte in the tanks for substantially simultaneously stopping the flow of air to one tank when the electrolyte therein falls to a predetermined level and starting a flow of air to the other tank when the surface of the electrolyte therein is above a predetermined level. As shown, this means includes solenoid operated three-way air valves AVI and AVZ which are arranged to control the flow of air to from the tanks ET! and ETI, respectively, by way of their respec- 6 ively associated

pipes

59 and 60 and surge coinpartments 6| and 62 for keeping electrolyte out of the. airlines Flow of electrolyteirom the tanks ET! and ETZ to the plating head is by way of pipes 63 and 64, respectively, through outlet check valves OCI. and 002 to a common pipe 65. The outlet check valves 0C! and 062 are. arranged to prevent How of electrolyte from the tank which is under air pressure to the tank which is not. While for convenience in illustration we have shown. the electrolyte tanks ET! and ETZ at diilerent elevations relatively to the electrolyte reservoir ER, it is to be understood that both tanks may be at the same elevation and preferably are below the reservoir so as to have gravity flow from the reservoir to the tanks, thereby eliminating the need for circulating pumps and the controls necessary thereto. It will. also be understood that the supply of electrolyte, may be replenished from time to time as required and suitable metallic salts or metal added to the electrolyte in a manner well known to the art.

For automatically controlling the flow of air into and out, of the tanks l and ETZ in response to the vel of the electrolyte therein, we provide a pl "ality of electrically interlocked re.- lays R2, P and wl" .h are arranged to be energized from a suitable preferably low voltage source ind-icated as a potential transformer T which has its high voltage winding connnected across basses 8i, the energization of which is arranged to be controlled in a manner hereinafter described. The interlocking arrangement of the relays R2, and Re is such that when the level or the electrolyte in the tank E'Ii' is above the bottom of electrode El and the transformer T is energized, the relay R2 is energized to effect through the closing of its upper contacts 68 the energization of the winding 69 of the air valve AV? whereby to open this valve and admit air to the tank. Also, with the closing of the middle contacts 10 of the relay R2, the relay Rd is energized to close its sealing-in contacts H and its lower contacts 72 in circuit with the winding of the relay R3. The relay R3, however, which through its upper contacts '13 controls the circuit of the winding 14 of the air valve AVE, cannot be energized as long as the lower contacts of the relay R2 are open. When, however, the relay R2 drops out because the level of. the electrolyte in the tank ETI falls below the bottom of the electrode El, the winding 69- of the air valve AV! is deenergized and the relay R3 is energized through the lower closed contacts '55 of the relay R2 and the lower closed contacts 52 of the relay Rt if the level of the electrolyte in the tank ET?! is above the bottom of the electrode E2 whereby to pick up and interrupt at its contacts 16 the circuit of the relay R2 and complete at its contacts "(3 the circuit of the winding it of the air valve AV2. While the electrolyte in the tank ET2 is flowing to the plating head, the tank ETi' is being refilled from the reservoir ER. When the level of the electrolyte in the tank ET2 falls below the bottomof the electrode E2, the relay R3 is deenergized to drop out the solenoid operated valve AV? and reenergize the relay R2 if the level of the electrolyte in the tank ET! is above the bottom of the electrode El. The relay R4 when once energized and sealed in remains in this condition as long as the transformer is energized. In order to avoid arcing between the solution and the electrodes Ei and E2, suitable resistances ii and it are respectively connected between the electrodes El and E2 and the'solu tions in the tanks ETI and EM.

For controlling the flow of electrolyte and rinsing liquid to and from the plating head in the sequence of electrolyte to the plating head, draining electrolyte therefrom, water to the plating head and draining water therefrom, we provide a multiple valve means MV which, as schematically shown, comprises suitably ported body portions BI and B2. The body portion BI is provided with valves VI, V3 and V and the body portion B2 with valves V2, V4 and V6, all spring biased to close. These valves are arranged to be actuated in a predetermined sequence by suitably shaped and angularly disposed valve cams CI through C6 which are rigidly mounted on a common shaft indicated by the dash-dot line SVS. This shaft is arranged to be actuated by suitable motive means such as a control motor CM working through a reducing drive 19. For the purpose of the drawing, the rotation of the shaft and the cams is clockwise as indicated by the arrow A. The common electrolyte flow pipe 65 from the tanks ETI and ET2 enters the valve body portion BI above the valve VI. When the valves VI and V3 are open and the other valves are closed, that is the cams CI through C6 have been turned clockwise about 90 from the positions shown, electrolyte can flow through a pipe 80 to the lower plating head member 5 by way of the pipe I3 and to the upper plating head member 6 by way of a pipe 8| which is flexible in order to accommodate itself to the movement of this upper plating head member. Electrolyte flow from the plating head is by way of the pipe I4 to the chamber above the valve V3, thence through this valve and a pipe 82 to the chamber above the valve V4 and return to the reservoir ER by way of a pipe 83. In order to reduce splashing and wave action in the reservoir ER, a battle wall 84 adjacent the pipe 83 is provided,

When the cams have been turned about 180, the valve VI is closed, the valve V4 is opened, the valve V3 remains open and the other valves remain closed. Electrolyte can now drain from each of the

plating head members

5 and 8 through the pipes I4, 80 and 82 and a pipe 85 to the reservoir ER by way of the return pipe 83. When the cams have been turned through about 270, the valves V2 and V5 are opened, the valves V3 and V4 are closed and the other valves remain closed. A rinsing liquid such as water can now flow from a source of water under pressure through a solenoid operated water valve WV, assumed open, to the chamber below the open valve V2 and thence by way of the pipes 85 and 80 to the plating head members 5 and 6 and return through pipe I4 to the chamber above the closed valve V3. The discharge of the water is then through the open valve V5 to a pipe 86 leading to a sewer or other suitable drain. When the cams have been turned about 360, the valves VI through V4 are closed and V5 and V6 are open, as shown. During this last 90 of movement, the valve V2 is quickly closed to stop the flow of water so that water can drain from both plating head members 5 and 5 b way of the pipes I4 and 8! and also by way of the pipes 80, 85 and a pipe 81 discharging to the sewer through the open valve VB.

For controlling the durations of flow of electrolyte to the plating head, the draining of electrolyte from the plating head and the flow of rinsing liquid to the plating head, we provide timing means. c mp g a p a n i er P a draining timer DT and a rinsing timer RT. As shown, eachv oi the timers comprises a. motor 88 which is arranged to drive through a solenoid operated clutch 89 a rotatably mounted contact controlling member 90 against the bias of a spring 9|. The member 90 is arranged to engage and close after a predetermined time a pair of normally open relatively movable contacts 82 which are adjustably positioned on a support 93 so that the time can be varied according to requirements. In accordance with our invention, these timers are arranged to effect the energization of the control motor CM at the end of the respective plating, draining and rinsing periods. For this purpose, the contacts 82 of the three timers are connected in parallel with each other and in series with the winding of a relay RI across the

busses

66 and 61. This relay, through its contacts 94, upon energization connects the control motor CM across the

busses

66 and 61.

For controlling the sequence of operation of the timing means and the flow of plating current to the plating head, we provide cyclic switching means S2, S3 and S4 which are arranged to be actuated by the control motor CM. As shown, each of the switching means is double throw and is arranged to be biased to one circuit controlling position by suitable resilient means such as a spring 95. For movement to the other circuit controlling position, the switch and valve shaft SVS is provided with suitably shaped and angularly disposed cams C8, C9 and CIO rigidly secured to the shaft and respectively arranged to actuate the switches S2, S3 and S4.

For controlling the energization of the plating current switch PCS and the plating timer PT, the winding 96 of the switch and the clutch winding of the timer are arranged to be connected in parallel across the busses B6 and 81 through conductors III and 91, the upper contacts of the switch S2 and the conductors 98 and 99. Similarly, the clutch winding of the draining timer T is arranged to be connected across the busses 66 and 8'! through conductors III and I00, the lower contacts of the switch S3 and the conductors 98 and 99. Also, the clutch winding of the rinsing timer RT is arranged to be connected across the

busses

66 and 61 through conductors II I and IIII, the upper contacts of the switch S4 and the conductors 98 and 99. For indicating purposes so that the operator may know the progress of the plating operation, we provide lamps L2, L3 and L4 connected in parallel with the clutch windings of the timers PT, DI and RT, respectively.

For the safety of the operator so that the plating head members cannot be released from the masking position while there is air pressure above a predetermined value in the top of the cylinder I and while the plating, draining and rinsing operations are under way, we provide an air control lock ACL having an energizing winding I02. This lock comprises a biased pivotally supported member I03 which is arranged upon energization of the winding I02 to engage an extension I04 on the handle H of the air control valve when it is turned clockwise about 90 from the position shown whereby to prevent movement of the handle and any change in the position of the air control valve. The operating shaft of the air control valve is indicated by the dash dot line I05. The circuit of the winding I02 of the air control lock ACL is arranged to be controlled by the lower contacts of a double throw switch SI which is arranged to be actuated by a cam 01 on the shaft SVS. When the electroplating apparatus is in the oil position shown, the lower contacts of the switch SI are open and the upper contacts closed, but the cam C1 is so arranged that quickly upon the starting of the motor CM the switch SI is operated to open its upper contacts and close its lower contacts and maintain this condition throughout nearly one revolution of the shaft SVS. The circuit of the air control lock winding I02 is across the

busses

66 and 61 on the deenergized side of the air pressure switch APS so that no locking can occur unless the plating head members 5 and 6 are in the masking position.

When it is desired to plate, a supply switch SS is closed on a suitable source of electric current and the work piece lis aligned transversely by the parallel motion mechanism and by longitudinal movement until the hole in the work piece is centered under the hole 43 in the locator 3 I. The air control valve handle H is then turned clockwise about 90 to admit air to the top of the cylinder I above the piston 9 and simultaneously the air below the piston is exhausted. Assuming the air pressure is above the desired value, the upper plating head member 6 is actuated to the masking position, the locator 3! being quickly swung to the off position as the plating head starts its downward movement, and the air pressure switch APS closes its contacts. A relay R5 connected across the

busses

66 and 67 then picks up. As long as the upper contacts of SI are closed, the relay R5 will remain energized even though the air pressure switch APS drops out because the relay R5 seals itself in through its own contacts in a circuit including a conductor H36, the upper contacts of the switch SI and a conductor I07 to the supply side of the air pressure switch APS.

To start the apparatus in operation, a manually operated switch such as a starting push button SP3 is closed. This switch completes the energizing circuit of the transformer T and the circuit of the winding of a relay R! which picks up and through its upper contacts seals in around the switch SPB. The energizing of the transformer T starts the sequence of operation of the relays R2, R3 and R4, heretofore described, so that electrolyte may flow from one of the tank's ET! or ET2 to the multiple valve mechanism MV and from the reservoir ER to the other tank. The closing of the lower contacts of the relay RI completes the circuit of the winding I68 of the water valve WV through a conductor 5",

I63 and the conductor I66 to the upper contacts of the relay R5. The circuit of the winding I08 of the water valve WV is also momentarily completed independently of the air pressure switch APS by way of the upper contacts of the switch SI and the conductor E61. Everything is now in readiness for the plating operation.

To start this operation, a switch such as a plating push button PPB is closed. This connects the winding of a plating control relay R6 and an indicating lamp Li in parallel therewith across the

busses

66 and 61 through a conductor III), the lower contacts of the switch S2, the upper contacts of the switch S3 and the lower contacts of the switch S4, all in series, and the conductor 99. The relay R6 then seals in through its upper contacts. Through its lower contacts, the relay R6 effects the energization of a'motor control relay R'I by connecting its winding to the conductor I which returns to the bus 61 by way of the 10 closed contacts of the switches S2, S3 and S4 as described for the circuit of the relay R6. With the closing of its contacts 94, the relay R'I connects the control motor CM across the

busses

66 and 67, and the switch and valve shaft SVS is started turning.

After a slight turning of the shaft SVS, the cam (31 opens the upper contacts of the switch SI and closes its lower contacts. The winding I63 of the solenoid operated water valve WV, however. remains energized through the lower contacts of the relay R! and the contacts of the relay R5 as heretofore described. With the closing of the lower contacts of the switch SI, the circuit of the winding I02 of the air control lock AC-L is completed from the bus 66 through the conductor Ill, a conductor II2, the lower contacts of the switch SI and a conductor II3 to the bus 61. As long as the air control lock is energized to engage the extension I64 on the handle H, the plating head members 5 and 6 must remain in the masking position, that is, as long as there is air pressure in the pipe I2 above a predetermined value.

Also. after the shaft SVS is turned clockwise a slight amount, the valves V5 and V6 close. After the shaft SVS is turned about the lower contacts of the switch S2 are opened and its upper contacts closed. The opening of the lower contacts of the switch S2 deenergizes the relays R6 and R1 and thereby effects the stopping of the motor CM. Also, the valves VI and V3 are opened. Electrolyte is now free to flow from whichever one of the tanks ETI or ETZ' is in service to both of the plating head members 5 and 6 through the valve VI and return by way of the valve V3 and the

pipes

82 and 83 to the reservoir ER. With the closing of the upper contacts of the switch S2 by the movement of the cam C6, the circuit of the winding of the clutch 89 of the plating timer PT is energized from the bus 66 through the conductor III- to the winding of the clutch, the conductor 91, the upper contacts oi the switch S2 and the conductors 98 and 99 to the bus 61. At the end of a predetermined time requisite for the desired thickness of plating, the contacts 92 of the plating timer PT are closed to effect the energization of the relay R! from the bus 66 through the winding of the relay R1, a conductor I54, the contacts 92 of the plating timer PT and a conductor II5 to the bus 61.

Upon reenergiz'ation of the relay R1, the oi"- cuit of the control motor CM is again energized and the shaft SVS started turning. After the shaft has again turned through approximately 90, the switch S2 is released by its cam C6 for its spring to open its upper contacts and close its lower contacts. The opening of the upper contacts deenergizes the clutch of the stalled motor plating timer PT which then opens its contacts 92 to deenergize the relay ET. This relay drcps out to deenergize the control motor CM. Also, after a small movement of the shaft SVS from the 93 position, the valve VI is closed to stop the flow of electrolyte tothe plating head members 5 and 6. By the time the shaft SVS is turned about the valve V d is opened. Electrolyte is now free to flow from both of the plating head members through the valves V3 and V6 to the reservoir ER by Way of the pipe 83. The time for this draining operation is controlled by the draining timer DT which is started into operation by the energization of the Winding of its clutch 89 when the cam C9 at the end of about 18%? of movement opens the upper contacts of the switch S3 and closes its lower contacts. The circuit of the clutch winding is then from the bus 65 through conductor III to the winding of the clutch, the conductor I00, the lower contacts of the switch S3 and the conductors 98 and 99 to the bus 61. At the end of a predetermined time requisite for draining the plating solution from the plating head members and 6, the contacts 92 of the draining timer DT are closed to reenergize the motor control relay R! through a circuit comprising a conductor I I G and the conductor H4, and the control motor CM is again energized to continue the clockwise rotation of the shaft SVS. After another approximately 90 of rotation of the shaft SVS, the switch S3 is actuated by its cam C9 to open its upper contacts and dcenergize the clutch of the stalled motor draining timer DT and to close its lower contacts. Also, the valves V3 and V4 are quickly closed. Also at the end of about 270 of rotation of the shaft SVS, the valves V2 and V5 are opened, but the other valves VI and V 5 remain closed. Water is now free to circulate by way of the valve V2 to the plating head members 5 and E and return by way of the pipe I4 and thence through valve V5 to the sewer. The switch S4 has also been actuated by its cam CIIJ to open its lower contacts and to close its upper contacts. Upon closing its upper contacts, the circuit of the winding of the clutch 89 of the rinsing timer RT is energized from the bus 66 through the conductor Hi, the winding of the clutch, the conductor IDI, the upper contacts of the switch S4 and the conductors 98 and 99 to the bus 51. At the end of the desired time for the rinsing operation, the contacts 92 of the rinsing timer RT are closed, and the circuit of the winding of the motor control relay R1 is again completed from the bus 57 through a conductor I I! and the conductor I I4 to the bus 66.

With the reenergization of the relay R1, the control motor CM is again started into operation to turn the shaft SVS. After another approximately 90 rotation, the switch S4 is released by its cam CID to open its upper contacts and thereby deenergize the clutch of the stalled motor rinsing timer and to close its lower contacts. The valve V2 is quickly closed to stop the flow of water to the plating head members 5 and 6. Also after about 360 of rotation, the valve V6 is opened. Water in the plating head then is free to drain through the pipes 8!] and it back into the valve body and thence to the sewer by way of the pipes 86 and 81. Also, at the end of the 360 of rotation of the shaft SVS, the lower contacts of the switch SI are opened to effect the deenergization of the air control lock ACL and the upper contacts are closed. The operator is now free to turn the handle H of the air control valve ACV counterclockwise and. move the plating head member 6 upwardly from the masking position. When this is done, the relay RE- and everything energized through the air pressure switch APS drop out and the parts are positioned as shown in Fig. 1 except for the relay R! which remains energized through the upper contacts of the switch SI to maintain solution and water pressures on the valve MV. The work piece I may then be moved along the supporting table on its rollers 4 for plating another spot or another work piece may be substituted as the occasion requires.

If at any time during the operation it is desired to stop the flow of air and water to the multiple valve MV, a normally closed switch such as a release push button RPB may be actuated to the,

12 open position whereby to deenergize the relay RI and the transformer T. This effects the closing of the water valve WV and whichever one of the air valves AVI or AV2 was open at the time.

For emergency operation after starting, we provide a normally open switch such as an emergency push button EPB. When this switch is closed, it energizes a supplementary motor control relay R8 through a circuit including a conductor II8, the lower closed contacts of the switch SI and the conductor II3. When the relay R8 picks up, it seals in through its lower contacts, and through its upper contacts it completes the energization of the motor control relay R1 in a circuit including this relay, a conductor H9, the upper contacts of the relay R8, the conductor II8, the lower contacts of the switch SI and the conductor H3. The motor control relay R1 completes the circuit of the control motor CM which then runs continuously to finish one revolution of the shaft SVS independently of the timers. .Vhen SI opens its lower contacts, relays R1 and R8 are deenergized and the control motor CM stops. In connection with this emergency operation, it 18, of course, assumed that the air pressure switch APS has its contacts closed.

For plating the outer Surface I 20 of the end of a contact stud I2I, we provide a plating head such as shown in Fig. 5, for example. As illustrated, this plating head comprises a suitably ported base I22 which is provided with an inlet pipe I23 for plating and rinsing liquids and a suitably secured sealing cap I24 tapped for an outlet pipe, as shown. Seated in a recess in the base I22 is a nozzle I25 having a plurality of discharge openings or ports I26 in liquid flow connection with the inlet pipe I 23 through a port in the pipe I 22. For centering, supporting and insulating the stud I2 I, the nozzle I25 is provided with a central portion I21 which is recessed for mounting an insulating shell I28. Within this shell is slidably and resiliently supported a centering element I29 movable in a sleeve I 33. For further insulating and also for masking purposes, we provide a sealing gasket I 3| which is centered by the sleeve I30. For directing the flow of electrolyte and rinsing liquid over the rounded surface I20 to be plated, we provide a shell I32 which, as shown, is in the form of a hollow frustrum of a cone with a generally spherical inner surface at its upper end, this surface being shaped to conform to the surface I20 to be plated. Also, as shown, the shell I32 is secured to the base of the nozzle I25. For confining the flow of liquids after passage through the nozzle I25 and between the shell I32 and the contact surface I20, we provide an outer housing I33 which is suitably secured to a flange on the base I22. For sealing the contact stud I2I against escape of liquids, we provide a sealing tube I34 of suitable material such as rubber. This also serves to insulate the stud from the remainder of the plating head structure so as to avoid a short circuit of the plating current circuit. As shown, the tube I34 is housed in a suitably shaped cover I 35 suitably secured to the housing I33. In accordance with our invention, this sealing tube I34 is .arranged to be supplied with air in a manner similar to the arrangement shown for the cylinder I in Figs. 1 and 2. Also, the stud I2I may be arranged to be held in the plating position by pneumatic means analogous to the arrangement shown in Figs. 1 and 2 for the plating head 6. For venting the liqu d chamber, a vent valve I36 is provided. With the arrangement shown in Fig.5, plating current connections are made to the base ['22 and to the stud I21 as will be appar- ;ent to" those skilled in the art. Apart from the differences described in the structure shown in Fig. 5, the operation is essentially the same as :for the arrangement shown in Fig. 1 embodying the'plating head arrangement shown in Figs. '2 and 3. In other words, there is no essential difference in the automatic controls and operation.

While we have shown and described our in- :vention in considerable detail, we do not desire to be limited to the exact arrangements shown, but seek to cover inthe appended claims all those modifications that fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In electroplating apparatus, a plating head adapted to be Supplied with plating current,

means for conducting electrolyte to the plating head and away therefrom and for conducting a "rinsing liquid to and from the plating head including valve means for sequentially controlling the flow of electrolyte and rinsing liquid to the plating head, timing means for controlling the durations of now of electrolyte to the plating head, draining of electrolyte from the plating head and flow of rinsing liquid to the plating head cyclic switching means for controlling the flow of plating current to the plating head and the sequence of operation of said timing means, and means for effecting the operation of said cyclic switching means and said valve means comprising motive means arranged to be inter-- .mittently actuated by the conjoint action of said piece, means for effecting relative movement of said members, a tank for electrolyte adapted to be supplied with air under pressure, means for conducting electrolyte from said tank to the plating head and away therefrom and for conducting a rinsing liquid to and from the plating head in cluding multiple valve means for sequentially controlling the flow of electrolyte and rinsing liquid to the plating head, timing means for controlling the durations of fiow of electrolyte to the plating head, draining of electrolyte from the plating head and flow of rinsing liquid to the plating head, cyclic switching means for controlling the flow of plating current to the plating head and the sequence of operation of said timing means, means for effecting the operation of said cyclic switching means and said multiple valve means, and means for preventing the release oi said members from said work piece before said switching means has completed a cycle of operations.

3. In electroplating apparatus, a plating head adapted to be supplied with plating current, tank for electrolyte adapted to be supplied with air under pressure, means for conducting electrolyte from said tank to the plating head and away therefrom and for conducting a rinsing liquid to and from the plating head including multiple valve means for sequentially controlling the flow of electrolyte and rinsing liquid to the plating head, timing means for controlling the durations of flow of electrolyte to the plating head, draining of electrolyte from the plating head and flow of rinsing "liquid to the plating head, cyclic switching means for controlling the flow of plating current 'to the plating head and the sequence of operation of said timing means, means for effecting the operation of said cyclic switching means and said multiple valve means comprising motive means arranged to be actuated intermittently by the conjoint action of said cyclic switching means and said timing means, and means adapted to be operated after the start of the plating operation for effecting a continuous operation of the motive means through the cycle of operations.

4. In electroplating apparatus, a plating head adapted to be supplied with plating current, a tank for electrolyte adapted to be supplied with air under pressure, means for conducting electrolyte from said tank to the plating head and away therefrom and for conducting a rinsing liquid to and from the plating head including multiple valve means for sequentially controlling the flow of electrolyte and rinsing liquid to the plating head, timing means for controlling the durations of flow of electrolyte to the plating head, draining of electrolyte from the plating head and flow of rinsing liquid to the plating head, cyclic switching means for controlling the flow of plating current to the plating head and the sequence of operation of said timing means, means for effecting the operation of said cyclic switching means and said multiple valve means comprising motive means arranged to be actuated intermittently by the conjoint action of said cyclic switching means and said timing means, and means for eliminating the conjoint effect of said cyclic switching means and said timing means on said motive means whereby to cause the motive means to run continuously through the cycle of operations.

5. In electroplating apparatus, a plating head, areservoir for electrolyte, two tanks adapted to be supplied with electrolyte from said reservoir and with air under pressure, and means for effecting a flow of electrolyte from either of said tanks to the plating head and thence to said reservoir including valve means operative in dependence upon the levels of the electrolyte in said tanks for stopping the flow of air to one tank when the surface of the electrolyte therein falls to a predetermined level and starting the flow of air to the other tank when the surface of the electrolyte therein is above a predetermined level.

6. In electroplating apparatus wherein a portion of a work piece is to be plated, a plating head comprising two relatively movable members adapted to be actuated to engage the work piece and constructed to mask the portion thereof to be plated when in engagement with the work piece, means for effecting the relative movement of said members, a reservoir for electrolyte, two tanks adapted to be supplied with electrolyte from said reservoir and with air under pressure,

and means for efiecting a flow of electrolyte from either of said tanks to the plating head and thence to said reservoir including electrically controlled valve means operative in dependence upon the levels of the electrolyte in said tanks for substantially simultaneously stopping the flow of air to one tank when the surface of the electrolyte therein falls to a predetermined level and starting the flow of air to the other tank when the surface of the electrolyte therein is above a predetermined level.

7. In electroplating apparatus wherein a portion of a work piece is to be plated, a plating head adapted to be supplied with plating current and comprising two relatively movable members adapted to be actuated to engage the work piece and constructed to mask the portion thereof to be plated when in engagement with the work piece, means for effecting the relative movement of said members, a tank for electrolyte adapted to be supplied with air under pressure, means for conducting electrolyte from said tank to the plating head and away therefrom and for conducting a rinsing liquid to and from the plating head including multiple valve means for sequentially controlling the flow of electrolyte and rinsing liquid to the plating head, timing means for conplating head and flow of rinsing liquid to the plating head, cyclic switching means for controlling the flow of plating current to the plating head and the sequence of operation of said timing means, and means for effecting the operation of said cyclic switching means and said multiple valve means including motive means arranged tobe intermittently actuated by the conjoint action of the cyclic switching means and said timing means.

8. In electroplating apparatus wherein a portion of a work piece is to be plated, a plating head adapted to be supplied with plating current and comprising two relatively movable members adapted to be actuated to engage the work piece and constructed to mask the portion thereof to be plated when in engagement with the work piece, pneumatic means for effecting the relative movement of said members, a tank for electrolyte adapted to be supplied with air under pressure, means for conducting electrolyte from said tank to the plating head and away therefrom and for conducting a rinsing liquid to and from the plating head including multiple valve means for sequentially controlling the flow of electrolyte and rinsing liquid to the plating head, timing means for controlling the durations of flow of electrolyte to the plating head, draining of electrolyte from the plating head and flow of rinsing liquid to the plating head, cyclic switching means for controlling the flow of plating current to the plating head and the sequence of operation of said timing means, motive means for effecting the operation of said cyclic switching means and said multiple valve means, means for controlling the flow of air to said pneumatic means, and means for preventing the operation of said air flow controlling means immediately upon engagement of the work piece by the plating head arranged to be released after said switching means has completed a cycle of operations.

9. In electroplating apparatus wherein a portion of a work piece is to be plated, a plating head adapted to be supplied with plating current and comprising two relatively movable members adapted to be actuated to engage the work piece and constructed to mask the portion thereof to be plated when in engagement with the work piece, pneumatic means for efl'ecting the relative movement of said members, a reservoir for electrolyte, two tanks adapted to be supplied with electrolyte from said reservoir and with air under pressure, means for conducting electrolyte from eachof said tanks to the plating head and thence to said reservoir and for conducting a rinsing liquid to and from the plating head including multiple valve means for sequentially controlling the flow of electrolyte and rinsing liquid to the plating head, valve means operative in dependence upon the levels of the electrolyte in said tank for substantially simultaneously stopping the flow of air to one tank when the surface of the electrolyte therein falls below a predetermined level and starting the flow of air to the other tank when the surface of the electrolyte therein is above a predetermined level, timing means for controlling the durations of flow of electrolyte to the plating head, the draining of electrolyte from the plating head and the flow of rinsing liquid to the plating head, cyclic switching means forcontrolling the flow of plating current to the plating head and the sequence of operation of said timing means, means for effecting the operation of said cyclic switching means and said multiple valve means, means for controlling the flow of air to said pneumatic means, and means for preventing the operation of said air flow controlling means immediately upon engagement of the work piece by the plating head arranged to be released after said switching means has completed a cycle of operations.

10. In electroplating apparatus wherein a portion of a work piece is to be plated, a plating head adapted to be supplied with plating current and comprising two relatively movable members adapted to be actuated to engage the work piece and constructed to mask the portion thereof to be plated when in engagement with the work piece, pneumatic means for effecting the relative movement of said members, a reservoir for electrolyte, a tank adapted to be supplied with electrolyte from said reservoir and with air under pressure, means for conducting electrolyte from said tank to the plating head and thence to said reservoir and for conducting a rinsing liquid to and from the plating head including multiple valve means for sequentially controlling the flow of electrolyte and rinsing liquid to and from the plating head, timing means for controlling the durations of flow of electrolyte to the plating head, the draining of electrolyte from the plating head and the flow of rinsing liquid to the plating head, manually operable switching means for starting the cycle of operations, cyclic switching means for controlling the sequence of operation of said timing means and the flow of plating current to the plating head, motive means for effecting the operation of said cyclic switching means and said multiple valve means, means for controlling the flow of air to said pneumatic means, means for preventing the operation of said air flow controlling means immediately upon engagement of the work piece by the plating head arranged to be released after said switching means has completed a cycle of operations, and means responsive to the pressure of the air holding the plating head in the work piece engaging position for preventing the flow of electrolyte and rinsing liquid to the plating head when the air pressure is below a predetermined value.

11. Electroplating apparatus comprising means for plating metal on a portion of the surface of a metallic work piece including two relatively movable members adapted to be mounted against the work piece on opposite sides thereof and provided with sealing means for masking the portion of the work piece to be plated upon relative movement of the members into engagement with the work piece, one of said members being chambered and provided with a curved surface diverter and an inlet port for supplying plating liquid under pressure with a tangential discharge against the diverter and said one member being provided with an outlet for plating liquid.

12. Electroplating apparatus comprising means for simultaneously plating metal on both sides of a metallic work piece around an opening therein including two relatively movable chambered members adapted to be centered over the opening in the work piece on opposite sides thereof and provided with sealing means for masking the portion of the work piece surfaces to be plated upon relative movement of the members into engagement with the work piece, each of said members being provided with an inlet for supplying plating liquid to the member for discharge against the work piece on opposite sides thereof and one of said members being provided with an outlet for plating liquid under pressure.

1 3. Electroplating apparatus comprisin means for plating metal around an opening in a metallic work piece including two relatively movable chambered members adapted to be centered over the opening in the work piece on opposite sides thereof and provided with sealing means for masking the portion of the work piece to be plated upon relative movement of the members into engagement with the work piece, a curved surface diverter centrally disposed in the chamber of each of said members, one of said diverters having an opening for liquid discharge and each of said members being provided with a port arranged for inflowing liquid under pressure with a tangential discharge against the diverter in the member.

14. In electroplating apparatus, a plating head, valve means for controlling the flow of electrolyte to and from the plating head, timing means, means for controlling said valve means to effect a flow of electrolyte to the plating head and for initiating the operation of said timing means, and means responsive to the operation of said timing means fOr controlling said valve means to stop the flow of electrolyte to said plating head and to drain the electrolyte from the plating head.

15. In electroplating apparatus wherein a portion of a Work piece is to be plated, a plating head comprising a movable member adapted to be actuated to engage the work piece and mask the portion thereof to be plated, fluid pressure means for effecting movement of said member, manually controlled means for controlling the supply of fluid to and from said fluid pressure means, control means for effecting the supply of electrolyte to the plating head, and means controlled by said control means for rendering said manually controlled means inoperative to control said fluid pressure means to effect the movement of said movable member from the work piece while there is electrolyte under pressure in the plating head.

16. In combination, an electroplating head having a supply conduit and a drain conduit, separately operable valves controlling the flow of electrolyte and rinsing liquid to the supply conduit, separately operable valves controlling the draining of electrolyte and rinsing liquid from the drain conduit, each of said valves having means normally biasing the valve to the closed position, and means including an electric motor-driven mechanism for opening said valves in a predetermined sequence, a trio of sequential- 1y operable timers controllin the energization :I of the driving motor .of said mechanism and sequential control means operated by the electric motor-driven mechanism for sequentially starting said timers intooperation to effect sequentially the flow of electrolyte to the plating head for a predetermined time interval, the

an electrolyte drain reservoir provided with check valve means for draining electrolyte from .the reservoir into either tank, means including separate electrically operated valves for applyingairpressure to each tank to produce flow of electrolyte therefrom to the head, and selective electrically operated switching means having separate control elements responsive to the level of the electrolyte in each tank for controlling the energization of said valves to to alternate the flow of electrolyte from the tanks.

18. In combination, a fluid pressure operating device having a control element for applyin fluid pressure thereto a movable electroplating open head having an operating connection for moving the head upon application of pressure to the device and provided with a sealing and insulating gasket for engaging a workpiece, plating control means including a timer having valve means controlled thereby and provided with conduits connecting the valve means for supplying electrolyte to the head for a predetermined interval and switching means controlled thereby for closing a plating circuit through the electrolyte between the head and the workpiece during said interval, and sequencing means for preventing starting the timer until after sealing operation of the head including a control element responsive to a predetermined fluid pressure applied to the operating device.

19. In combination, an opposite pair of relatively movable electroplatin open head members, a fluid pressure device having operating connections with one head member for eifecting relative movement thereof upon application of fluid pressure to the device, each head member being provided with a sealing and insulating gasket for engaging a workpiece therebetween, and means for controlling operation of the head members including a control element for applying fluid pressure to said device and sequential timing means having a separately operable manual starting control element and a control element responsive to a predetermined fluid pressure applied to the device for rendering said manual control element effective and including a first timing element having valve means controlled thereby and provided with conduits for controlling the supply of electrolyte to each plating head member and switching means controlled thereby for controlling closing a plating circuit through the electrolyte between each plating head member and the workpiece and a second timing element having valve means controlled thereby and provided with conduits for controlling the draining of electrolyte from each platin head member and a third timing element having valve means controlled thereby and provided with conduits for controlling the supply of rinsing liquid to each plating head member during successive time intervals 19 after the efiective operation of the manual starting control element.

20. In combination, an electroplating head having a supply conduit and a drain conduit, separately operable valves connected with the supply conduit for controlling the flow of elec trolyte and rinsing liquid to the supply conduit,

separately operable valves connected with the drain conduit for controlling the draining of electrolyte and rinsing liquid from the drain conduit, each of said valves having means normally biasing the valve to the closed position, and means including an electric motor-driven mechanism for opening said valves in a predetermined sequence, and a trio of sequentially operable timers for controlling the energization and deenergization of the driving motor of said mechanism to efiect sequentially the flow of electrolyte to the plating head for a predetermined time interval, the draining of electrolyte from the 0 plating head for a predetermined successive time interval, and then the flow of rinsing liquid REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 565,975 George Aug. 18, 1896 1,885,702 Fink Nov. 1, 1932 2,225,350 Rankin Dec. 17, 1940 2,325,401 Hurlston July 27, 1943 2,352,283 Overholt June 27, 1944 2,404,948 Croco July 30, 1946 FOREIGN PATENTS Number Country Date 26,504 I Great Britain of 1912 483,503 Great Britain Apr. 21, 1938 Certificate of Correction Patent No. 2,519,945

KARL A. W. TWELE ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 17, lines 19 and 20, strike out the Words under pressure and insert the same in 11116 16, same column, after llquld; column 18, llne 23, strike out to second occurrence;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Ofice.

Signed and sealed this 27th day of March, A. D. 1951.

August 22, 1950 [SEAL] THOMAS F. MURPHY,

Assistant Gammz'ssz'oner of Patents.

Claims

1. IN ELECTROPLATING APPARATUS, A PLANTING HEAD ADAPTED TO BE SUPPLIED WITH PLATING CURRENT, MEANS FOR CONDUCTING ELECTROLYTE TO THE PLANTING HEAD AND AWAY THEREFROM AND FOR CONDUCTING A RINSING LIQUID TO AND FROM THE PLATING HEAD INCLUDING VALVE MEANS FOR SEQUENTIALLY CONTROLLING THE FLOW OF ELECTROLYTE AND RINSING LIQUID TO THE PLATING HEAD, TIMING MEANS FOR CONTROLLING THE DURATIONS OF FLOW OF ELECTROLYTE TO THE PLATING HEAD, DRAINING OF ELECTROLYTE FROM THE PLATING HEAD AND FLOW OF RINSING LIQUID TO THE PLATING HEAD, CYCLIC SWITCHING MEANS FOR CONTROLLING THE FLOW OF PLATING CURRENT TO THE PLATING HEAD AND THE SEQUENCE OF OPERATION OF SAID TIMING MEANS, AND MEANS FOR EFFECTING THE OPERATION OF SAID CYCLIC SWITCHING MEANS SAID VALVE MEANS COMPRISING MOTIVE MEANS ARRANGED TO BE INTER-