US2867574A

US2867574A - Fluid electrical contact device and support therefor

Info

Publication number: US2867574A
Application number: US637761A
Authority: US
Inventors: Ernest V Berry
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-02-01
Filing date: 1957-02-01
Publication date: 1959-01-06
Anticipated expiration: 1976-01-06

Description

Jan. 6, 1959 E. v. BERRY 2,867,574

FLUID ELECTRICAL CONTACT DEVICE AND SUPPORT THEREFOR Filed Feb. 1, 1957 2 Sheets-Sheet 1 E. V. BERRY Jan. 6, 1959 FLUID ELECTRICAL CONTACT DEVICE AND SUPPORT THEREFOR Filed Feb. 1, 1957 2 Sheets-Sheet 2 w v w I Ill-Ill! ||l\|| lk llllim llliill 1 H IHHH W W d WW 5 sm w ill: 7 NW m6 .hrmrg W WN 1k Cw WIN R I M J 03v v .Wh, AW W N qwwq w w \N \q United State FLUID ELECTRICAL CONTACT DEVICE AND SUPPORT THEREFOR Ernest V. Berry, Los Angeles, Calif. Application February 1, 1957, Serial No. 637,761

4 Claims. c1. 2o4 -21z My invention relates to the field of electroplating, and more specifically to a structure particularly effective in chromium plating crank pins and main journals of crankshafts, as well as other cylindrical surfaces such as calendar rolls, and the like.

The previously available apparatus and methods for electroplating cylindrical surfaces with a layer of hard chromium have been found unsatisfactory in that it is extremely difficult to deposit a layer thereof of uniform thickness and proper homogeneous hardness, brightness and density. The difficulties encountered in obtaining the desired results with previously available apparatus and methods stem from the fact that the electro-chemical reactions involved in chromium electroplating are not clearly understood. As a result, improvements in both the apparatus and methods employed must be made from an empirical approach, rather than from a theoretical standpoint.

In contrast to plating with most other metals, commercial chromium electroplating is not carried out in a bath that is an aqueous solution of one of its salts, but instead an electrolyte is employed that is a water solution of chromic and sulphuric acids. In addition, an insoluble anode is utilized in this chromic acid bath.

The chromium in a chromic acid bath is initially in the hexavalent state, but has a tendency to be reduced to the trivalent state during the plating operation. It is most important to hold the trivalent chromium content of the plating bath to a minimum in order to attain chromium plating of uniform physical characteristics.

In the past, the chromium plating of main journals and crank pins of crankshafts has been accomplished by rotating the crankshaft in a chromic acid bath in which the crankshaft serves as a cathode. Arcuately-shaped anode plates are then disposed adjacent the cylindrical surfaces to be plated, with the cathode and anode connected to a suitable source of direct electrical power. From experience it has been found that this method of chromium plating is unsatisfactory as it is virtually impossible to deposit a chromium layer of uniform thickness on a cylindrical surface thereby.

By trial and error it has been found that the plating characteristics of a chromic acid bath are most sensitive to changes in the temperature thereof, the current densities on the anode and cathode, the pH of the bath, and the chromic and sulphuric acid content thereof. For instance, an increase in the concentration of chromic acid in the bath increases the conductivity thereof, but, at the same time, decreases the cathode efficiency so that in many cases a higher current density does not increase the rate of chromium deposit. As another illustration of a change in the plating characteristics of-a chromic acid bath, it has been found that an increase in current density at a given temperature causes the appearance, hardness and density of the deposited chromium to vary. In other words, the appearance of the deposited chromium may be caused to progress from (1) milky to (2) bright to (3) frosty, and finally to (4) burnt, by simply increasing the i atented Jan. 6, 1959 current density. However, an increase of current density on the anode increases the rate at which the objectionable trivalent .chromium forms in the chromic acid bath. Therefore, it will be apparent that obtaining a hard, bright layer of electro-depositcd chromium of uniform thickness on a.cylindrical surface is a matter involving a number of variables which must be maintained in equilibrium to provide optimum plating conditions.

It will also be recognized that the variables influencing whereby a uniform deposit of chromium of the desired brightness, hardness and density may be deposited thereon.

A major object of my invention is to supply an electrical contact apparatus particularly adapted for chromium electroplating, embodying a structure in which a fluid surrounds a crankshaft and acts as the electrical contact therewith.

A further object of my invention is to provide an apparatus which is simple in operation, readily adapted to pre-existing electroplating installations, may be operated by relatively inexperienced personnel, and assures the production of electroplated cylindrical surfaces of a uniform and quality standard.

These and other objects and advantages of my invention will become apparent from the following description of my plating method, and from the drawings illustrating an apparatus therefor in which:

Fig. l is a cross-sectional view of a plating tank showing my vertically movable apparatus for rotatably supporting a crankshaft as the cathode mounted therein, and with the anodes of my invention operatively associated with the main journals and crank pins for the plating thereof;

Fig. 2 is a combined vertical cross-sectional view of the plating tank and an end elevational view of the apparatus utilized in rotatably supporting a crankshaft;

Fig. 3 is a fragmentary vertical cross-sectional view of the plating tank and a side elevational view of one of my anodes disposed therein;

Pig. 4 is a fragmentary vertical cross-sectional view of one of the supports for a rotating crankshaft taken on line 4-4 of Fig. 2, also showing the fluid contact in detail.

The general arrangement of the apparatus used with my method of electroplating cylindrical surfaces may best be seen in Figs. 1 to 4, inclusive. An elongate electroplating tank T is provided that has horizontal and outwardly disposed flanges F formed on the upper edges of the side walls thereof. The vertically adjustable mechanism M is adapted to rotatably support a crankshaft C in a substantially horizontal position within tank T, with the crankshaft being rotated by a motor E when so supported- A number of anode structures S rotatably engage the main journals J and crank pins P of the crankshaft when it is supported by the mechanism M. The detailed structure of the preferred form of my anode structure is illustrated and described in my copending application, Serial No. 364,5 69, now Patent No. 2,782,159, filed June 29, 1953, and entitled Electroplating Anode Structure and Method of Using Same, of which this application is a continuation-in-part.

Tank T is rect-angularly-shaped, and from the bottom 11 thereof end pieces 12, 12' and side walls 13, 13' project upwardly to terminate in flanges F. Each flange F afiixed to side walls 13 and 13' supports two parallel, laterally spaced bus bars 14, and 14, 15 respectively. Bus bars 14, 14 (see Fig. 2) occupy inwardly disposed positions higher in elevation than bus bars 15, 15. The bus bars 14, 15, ld'and :15 are supported-from flange F'byelect'rical insulators 16. Bars .14, 14' are connected to the positive (terminal of -.a source .of direct electrical power (not shown), and bars 15, .15 to the negative terminal of the same source of power. The bus bars 14, '14 serve to supply electricalenergy to the anodes Sias will hereinafterbe explained in detail,:and .bars 15, 15' supply electrical energy to the.crankshaft C, which serves as the cathode.

Crankshaft-supporting mechanism M, best seen iniFigs. l and 2, includes an elongate, horizontally dispose'tlrigid member 2t Two vertically disposed supports 21' depend downwardlyfrom the endportions of member 20, saidsupports each having a combined bearing and rotary electrical contactZZand 22', respectively, mounted on the lower ends-thereof. -Since contacts .22 and 22' are ofidentical construction, only one of them will be described.

In Fig. 4 one of the combined bearing and rotary electrical contacts is shown, audit willbe seen to include a'horiz ontally disposed cylindrical shell 23 rigidly afiixed to the lower end of support 21. The end portions of shell 23 are tapped, with the outwardly disposed end of said shell having a plug 24-threaded therein. A hearing 25 is formed as a part of plug 24 situated within the confines of the shell 23. The inwardly disposed end of shell 23Ihas a threaded sleeve .26 mounted therein. The inwardly disposed end portion of a horizontal shaft 27 is rotatably supported in shell 23 by bearing 25 and sleeve 26.

Shell 23 has an opening 23 formed in the upper portion thereof communicating with a vertically positioned tube 29. Tube '29 permits the introduction of mercury Y into the confines of shell 23, and serves as a housing for an electrode 39 that contacts the mercury after it is so introduced. The electrode 3%? is surrounded by sleeve 30:: formed of insulating material. This sleeve properly spaces the electrode and also insulates it from the housing 22 so that the current passes directly from the crankshaft through shaft 27, then through the mercury Y to the electrode 31?. Escape of mercury Y from shell 23 is prevented by means of two annular resilient seal ng gaskets 31 and 31 encircling shaft27'which are compressed between body shoulders 32, 32' and'the inwardly disposed ends of bearing .25,.and sleeveldrespectively. Electrode St has an insulated electricalconductor 33 extending therefrom to a clamp 34 that is removably affixed to one of the bus-bars 15 or .15. Themercury Y disposed in shell .23 assures agood electrical connection between electrode 3ilandshaft'27, irrespective of whether the shaft is. stationary or. rotating.

An annular flange.35:is mounted on shaft 27, which flange is acompanion to-flange 3.6, which is an integral part of the .crankshaftC. The two

flanges

35 and 36 are removably held together by bolts 37. end portion of crankshaft C and shaft .27 are removably connected to one another by a collar 38. Shaft 27 has a sprocket 39-mounted thereon that engages an endless chain belt 40, which belt extends upwardly for engagement with a sprocket 41 mounted on a jack shaft 42. Jack shaft 42 is provided with a pulley 43 driven by an endless belt 44 extending upwardly toa driving pulley 45 on motor E. Motor E and jack shaft 42. are supported on a rectangularly-shaped frame 46 rigidly connected to member 29. A similarly shaped frame 46' is provided on theopposite end portion of member 20. Frames 46,

-.46'--areprovided with heavy cross pieces '47, 47, respectively, which cross pieces have centrally disposed slots c48,,,48"formed. thereinfor engagement with hooks 49 The opposite.

of longitudinally spaced pairs of electrically insulated, vertically disposed eyes 50 mounted thereon, each pair of which slidably supports two parallel, laterally separated, electrical conducting tubular members 51, 51'. Each member 51, 51' has a terminal 52, 52', respectively, mounted on the upper end thereof, and insulated electrical conductors 53 extend from terminals 52, 52' to clamps 54- that may be removably aflixed to one of the bus bars 14, 14. .Each pair of .tubular members-51, 51' forms a part of one of the anodes S, the detailed structure of which may best be seen in my copending application, Serial No. 364,569, before-referred to. V

The application of my-invention isextremely simple. Mechanism M, inasmuch as .it is supported from chain falls, may be easilylowered into or raisedfrom the electroplating tank T. This particular mode of supporting mechanism M is of a distinct advantage, as it permits free use thereof with any one .Qf a number .of electroplating tanks. The structure of mechanism proyides a further advantagelin that the supports ;2 i,'.;21'. ana the frames 46, iassociated therewith may be longitudinally adjusted on member 2% by use oflsuitable means 18,0, Pig. 2. Thus, by longitudinal adjustment of supports 21 and 2.1, the mechanism may be adapted to rotatably support crankshafts C of various lengths.

After a crankshaft C is rotatably supported by the mechanism M, the anode structures S are mounted on the mechanism in the positions shown infFig. 1. Motor E is then actuated, causing crankshaft'C to rotate at a uniform rate of speed. The electrical circuit used in the plating operation is completed when electrical currentis supplied to the crankshaftC serving as the cathodethrough the rotary mercury contact (Fig.4). As the crankshaft C is rotated, those anodes S resting on the crank jpins P by means of wheels 65 will reciprocate up and down as they follow the circularpath .of the pins, with the tubular members 51, .51 :being slidably guided .by the eyes 50. Those anodes S resting on the main journals I will, of course, not be subjected to jreciprocatorymotion. The anodes have end sheets .with openings 67 therein.

It has been found that my plating apparatuswillopcrate in a consistent and uniform manner after extensive use and provide results ofa muchhigher quality. than heretofore available.

From the foregoing it will be seen that I have provided a fluid contact device by means of which electrical current may be effectively transmitted from arotating member, suchas a crank shaft or thelike, to anelectrode whichis immersedin a fluid which lsur rounds't he crank shaft or the like. In actual use the fluid contact of the present application is the only one tested so far that'has been found to be capable of carrying a six volt current at approximately 6000amperes.

Although my invention is fully, capable of achieving the results and providingthe advantages hereinbefore mentioned,it is to be understood .that it is merely. the presently preferred embodiment thereof, and that'l do not mean-to be limited to the details of construction above described other than as defined inthe appended claims.

I claim:

1. A device for electroplating the curved surface of an elongate cylindrical member, which includes: a. rigi d, horizontally disposed elongate member; supporting means that permit it to be raised or lowered relative to an electro-plating tank; two supports .depending downwardly from saidmember which are longitudinally adjustable thereon; twohorizontally disposed housings aifixed to the lower ends of said supports; .a vertically disposed tubular member which extends upwardly fro-mono ofsaid housings and communicates with the interior thereof;. two horizontal shafts rotatably supported in said housings and projecting from the inwardly disposed ends: thereof; means mounted on the inwardly :disposed ends of :said shafts to removably engage the end portions of saidcylindrical member for the rotatable support thereof; an elongate electrical contact member projecting downwardly through one of said tubular members to contact a body of metallic electrical-conducting fluid disposed within said housing and in contact with one of said shafts; means to rotate said cylindrical member and said horizontal shafts; an anode adjacent said curved surface; and means connecting said contact member and anode to a source of electrical power to allow electroplating of said cylinder when disposed within the confines of said tank.

2. A device for electroplating the curved surface of an elongate cylindrical member, which includes: a rigid, horizontally disposed elongate member; supporting means that permit it to be raised or lowered relative to an electroplating tank; two supports depending downwardly from said member which are longitudinally adjustable thereon; two horizontally disposed housings aflixed to the lower ends of said supports; two vertically disposed tubular members which extend upwardly from said housings and communicate with the interiors thereof; two horizontal shafts rotatably supported in said housings and projecting from the inwardly disposed ends thereof; means mounted on the inwardly disposed ends of said shafts to removably engage the end portions of said cylindrical member for the rotatable support thereof; two elongate electrical contact members projecting downwardly through said tubular members to contact bodies of metallic electrical-conducting fluids disposed within said housings and in contact with said shafts; packing means that prevent escape of said bodies of metallic fluid from said housings; means to rotate said cylindrical member and said horizontal shafts; an anode adjacent said curved surfaces; and means connecting said contact members and anode to a source of electrical power to allow electroplating of said cylinder when disposed within the confines of said tank.

3. In a device for electroplating the curved surface of an elongate cylindrical member; a horizontally disposed housing; a vertically disposed tubular member which extends upwardly from said housing and communicates with the interior thereof; a horizontal shaft rotatably supported in said housing and projecting from the inwardly disposed end thereof; means mounted on the inwardly disposed end of said shaft to removably engage an end portion of a horizontally disposed cylindrical member for the rotatable support thereof; an elongate electrical contact member projecting downwardly through said tubular member to contact a body of metallic electrical-conducting fluid disposed within said housing and in contact with said shaft.

4. A device for electroplating the curved surface of an elongate cylindrical member, which includes: a rigid, horizontally disposed elongate member; supporting means extending upwardly from said member that permit it to be raised or lowered relative to an electroplating tank; two supports depending downwardly from said member which are longitudinally adjustable thereon; two cylindrical, horizontally disposed housings aflixed to the lower ends of said supports; two vertically disposed tubular members which extend upwardly from said housings and communicate with the interiors thereof; two horizontal shafts rotatably supported in said housings and projecting from the inwardly disposed ends thereof; means mounted on the inwardly disposed ends of said shafts to removably engage the end portions of a horizontally disposed cylindrical member for the rotatable support thereof; two elongate electrical contact members projecting I downwardly through said tubular members to contact bodies of metallic electrical-conducting fluids disposed within said housings and in contact with said shafts; packing means that prevent escape of said electrical-conducting fluids from said housings; a driven member mounted on one of said shafts for the rotation thereof; a

driving member; power-transmitting means operatively connecting said driven and driving members; an anode adjacent said curved surface; and means connecting said contact members and anode to a source of electrical power to allow electroplating of said curved surface when disposed within the confines of said tank.

References Cited in the file of this patent UNITED STATES PATENTS 1,170,388 Anschutz-Kaempfe Feb. 1, 1916 1,669,653 Campbell May 15, 1928 2,530,677 Berkenkotter Nov. 21, 1950 FOREIGN PATENTS 146 Great Britain of 1906 117,302 Australia July 22, 1943

Claims

1. A DEVICE FOR ELECTROPLATING THE CURVED SURFACE OF AN ELONGATE CYLINDRICAL MEMBER, WHICH INCLUDES: A RIGID, HORIZONTALLY DISPOSED ELONGATE MEMBER; SUPPORTING MEANS THAT PERMIT IT TO BE RAISED OR LOWERED RELATIVE TO AN ELECTRO-PLATING TANK; TWO SUPPORTS DEPENDING DOWNWARDLY FROM SAID MEMBER WHICH ARE LONGITUDINALLY ADJUSTABLE THEREON; TWO HORIZONTALLY DISPOSED HOUSINGS AFFIXED TO THE LOWER ENDS OF SAID SUPPORTS; A VERTICALLY DISPOSED TUBULAR MEMBER WHICH EXTENDS UPWARDLY FROM ONE OF SAID HOUSINGS AND COMMUNICATES WITH THE INTERIOR THEREOF; TWO HORIZONTAL SHAFTS ROTATABLY SUPPORTED IN SAID HOUSINGS AND PROJECTING FROM THE INWARDLY DISPOSED ENDS THEREOF; MEANS MOUNTED ON THE INWARDLY DISPOSED ENDS OF SAID SHAFTS TO REMOVABLY ENGAGE THE END PORTIONS OF SAID CYLINDRICAL MEMBER FOR THE ROTATABLE SUPPORT THEREOF; AN ELONGATE ELECTRICAL CONTACT MEMBER PROJECTING DOWNWARDLY THROUGH ONE OF SAID TUBULAR MEMBERS TO CONTACT A BODY OF METALLIC ELECTRICAL-CONDUCTING FLUID DISPOSED WITHIN SAID HOUSING AND IN CONTACT WITH ONE OF SAID SHAFTS; MEANS TO ROTATE SAID CYLINDRICAL MEMBER AND SAID HORIZONTAL SHAFTS; AN ANODE ADJACENT SAID CURVED SURFACE; AND MEANS CONNECTING SAID CONTACT MEMBER AND ANODE TO A SOURCE OF ELECTRICAL POWER TO ALLOW ELECTROPLATING OF SAID CYLINDER WHEN DISPOSED WITHIN THE CONFINES OF SAID TANK.