|Publication number||US2473290 A|
|Publication date||Jun 14, 1949|
|Filing date||Oct 21, 1944|
|Priority date||Oct 21, 1944|
|Publication number||US 2473290 A, US 2473290A, US-A-2473290, US2473290 A, US2473290A|
|Inventors||George E Millard|
|Original Assignee||George E Millard|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (13), Referenced by (62), Classifications (13)|
|External Links: USPTO, USPTO Assignment, Espacenet|
June 14, 1949. G. E. MILLARD APPARATUS FORl PLATING JOURNALS OF CRANKSHFTS Filed Oct. 2l, 1944 obo INVENToR. ko/'ge IWW/0rd ATTORNEYS Patented June 14, 1949 UNfl'lilEgD STATES PATE-Nr ori-lcs APPARATUS FOR PLATING JOURNALSOFv CRANKSHAFTS 3 Claims. 1
'Ifhisv invention; relates* to apparatus for plating the journals of a crankshaft.
More particularly the invention relates tothe el'e'ctroplating ofV the journals of crankshafts, suclll las crankshafts-employed in internal combustion engines, with a suitable metal, as chromium.
Whilemy invention isiapplicable to the plating ofthe journals oi?L newly Imanufactured crankshaft's, an 'important use of 'my invention is in the reclaiming of crankshafts of which the journals have become worn; Therefore, as an illustrationbut not as a limitation, my invention will be-more particularly described in connection with the reclaimingof crankshafts, the journals of whichlhave become worn.
-Heretofore in reclaiming crankshafts having worn journals, two procedures have been followed One procedure was to grind the journals downto the next undersize and to employ an undersizedcap-orbearing to fit the new size to whicli'the journals of the crankshaft had been ground; This procedure resulted in having a mc'to'rlwith journalsand main and connecting rod-bearings therein Which'were not of standard size and in caseA of later repair work, this is a serious--diliculty The-amount of crankshafts recliaime'dfin 'this manner is in part illustrated byf-the"'factthat 'the War Production Boardhas ver-yf-greatly limited the manufacture of undersize'dbearings. Due tothe fact that motor difficulties may develop requiring replacement of bearings-'and at great distances from the manufacturer of fthe motor, a motor having off size or freaki parts as distinguished from standard parts, presents very serious difficulty. Therefore,v the practice has been to attempt toreconditioncrankshafts -so that they are substantially duplicates of the crankshafts as originally manufaoturedf so that thereafter standard parts may beemplo'yed. Also, Aany grinding of crankshaft journalsrfobviously removes some ofthe parent metal'vfrom the journals and thus somewhat weakens the` crankshaft.
Thesecond methodheretofore employed-which attempted to provide reclaimed -crankshaf-ts with standard journals was the process generally termed the sprayed metal. process. In such process -the bearings were cut with deep and ragged? thread-'like grooves and Athen lmolten metal sprayed to form a continuous lm about the sof :rougliened journal. Thereafter, the `j ournal'iwas'ground and'honedldown to standard size.
A primary. shortcorningvinrtlie fsprayedmetall process of-f adding metalitoj: the crankshaft ljournals is that -therst-step 4requires roughening and grinding away of `parent metal from the crankshaft journals vandcutti'ng deep Land ragged thread-like groovesandthus a weakened 'crankshaft. In the tsprayed metal process there is substantially-no'fusion between the metal added andy the crankshaft' and there is merely a fusion cf all of i thev metal added -andirelative motion between thelringsl oradde'dmetal andthe parent metal or the original-crankshaft is prevented because of-'the roughenedconditionand deep ragged thread-'like grooves in the crankshaft. In any member subject to-'severestress sharp corners are `always'avoided'fbecause sharp corners become'fa focal point for-the beginning of cracks.
Another-difficulty V`encounteredfin the sprayed metal proc'esswas thefact that vthe ymetal was not-sprayedaevenly 'about ajournal of the crankshaft and this 'fact was-reflected-by inaccuracy in the-later grinding-andpolishingfof the journal'l surf-ace.v
The vlater grinding di'f'culty resulting from uneven coa-ting of the- 4journals `by* sprayed metal was" more` evident in the connecting rod bearing journals asfdistinguished from' the lmain bearing journals. In themanufacture`- of crankshafts, the lathe centermarksor'tlie centers of the crankshaft arevrstldeterminedand then by the lathe operationthe; mainIv bear-ing journals are completedabout-fsuch centers. These centers, i. er, conical'depre'ssions,are'ileft inthe-ends of the crankshaf-ts.: Thereafter; Vwhen a worn crankshaft' is reinserted'na lathe'and when the same centers'far-eemployed',` the-main bearing journals can be trued up so that they willhave thefcriginalfcenters'.` Onfthc-othe'r-hand, in the manu-facture-lofcrankshafts-specialjigs and tools are .employedLl-todetermine- `-the' -f centers of the connectingtrodbearingjournals;V Asa set of tools` and jigs fis necessary fori eachV crankshaft, and as the tools and jigs' which-are originally employed v'wear and -lnewfonsimust'replace them, iti isnot' practical-to-employmethodsf in reclaiming crankshaft's where :ar/special set of jigs and dies will-be required for each-itypeof crankshaft ever made; Thusin regrinding =`a connecting-'rod bearing journal;rto'cls'I areemployed whichl'will find the apparent center @tithe-connecting rod bearing jour-'nall-ir1-volveddependingupon the eX- terlnall surfacesv- Obvimislyi,"if` the-connecting rod journal has` been'- built i4up rby" adding sprayed metal thereto, any variation rin the-'thickness of sprayed imetal-adddllwill-:change the'VIA apparent centerlandf-,thusl th-connectingrodtbearirig` jourbeing built up as distinguished from being ground on its true or original center. Any change in the true center of the connecting rod will change the timing of the motor and either make the motor run rough or, in case of Diesels, will change the actual firing time. rIhus, precision work in building up worn connecting rod bearing journals of crankshafts to their original size requires that the plating or the coating which is added to the journal shall be a uniform coating or plating and the sprayed metal process has had a shortcoming in failing to provide for a uniform addition of metal to the journal to build the same up to its original size. In addition to the non-uniformity of the addition of metal by the sprayed metal process there is a further complication that a journal may be out o f. round due to wear, and there is always a possibility 'of adding the error due to the journal being out of round to the error in the amount of coating so that at times the two errors are additive in their eects.
Another diiculty of the ,sprayed metal process is that the sprayed metal is not of the desired hardness and is subject to Wear.
In view of such shortcomings in the prior commercial art of reclaiming crankshafts, it is an object of my invention to reclaim crankshafts without any initial grinding and initial weakening of the shaft so that none of the parent metal of the crankshaft is removed.
Next, it is an object of my invention to provide apparatus for chromium plating by an electrolysis process the crankshaft bearing journals and to provide a substantially uniform deposit of chromium thereon. This is particularly valuable in that it results in an economy in the process in not requiring excess chromium plating and next the apparent center of a journal is not changed by reason of unequal deposits of chromium. Inasmuch as the general grinding practice is to line up the journal to be ground by reason of its exterior surface, it is obvious that if the chromium plating is not uniform, the final exterior will not be uniform and the center of the journal will be changed over the original designed center thereof. Non-uniform plating of chromium is not only objectionable in changing the timing and stroke of a motor but at the same time if a deposit of chromium is non-uniform, then often after nal grinding, the chromium is too thin on some sides or may be even non-existent and is heavy on others. In View of the extreme hardness and wear resistance of chrome plating it is obviously advantageous to provide a uniform wearing surface.
Another object of the invention is to provide for chromium plating of the crankshaft bearing journals not only uniformly, so far as depth of plating is concerned, but lengthwise of the journals so that the bearing surface thereof will be the original surface area.
It is a further object of the invention to provide means to continuously wipe the journals during plating, which wiping, among other effects, apparently causes the gases liberated during the electro-plating process to be properly and promptly removed so they will not affect the uniformity of the plating.
Another object of the invention is to provide apparatus which result in substantially uniform current density between the anode and cathode to thereby result in uniform plating.
Another object of the invention is to provide means so that as the crankshaft is rotated in an electrolyte during electro-plating, there will be no 4 wear on the original lathe or center marks of the crankshaft.
Another object of the invention is to provide apparatus whereby if the anode should be accidentally removed from the crankshaft during plating, the anodes will be thrown clear of the bearing journals and thus preventing any short circuiting with such journals which would in turn cause arcing with and burning of the bearing journals and very possibly ruining the same because of change of hardness at the burned location.
It is a further object of the invention to pro- Hvide aV chromium plating apparatus for the bearing journals of a crankshaft which is of such accuracy that if it be desired, a crankshaft may be ground or originally formed to a predetermined amount less than the final size desired, such as five-thousandths undersize, and then a plating of five-thousandths of an inch of chromium may be applied and the crankshaft used Without any further grinding of the crankshaft.
With my invention I have been able to readily control the depth of plating within ten (10%) percent of the thickness desired. In other Words, if a ten-thousandths of an inch deposit is desired, my process is being operated so that within the tolerance of one-thousandth of an inch, that is, plus or minus, the deposit may be obtained. An important result of bein-g able to so control the thickness of the plating is that, if desired, the nal grinding operation can be eliminated and it should be noted that the final grinding operation in a crankshaft having chromium plated bearing journals is particularly important in that the chromium is exceptionally hard and much more difficult to grind than is steel. Also, of course, by being able to chromium plate to size, no more chromium is applied than is actually needed.
The above mentioned general objects of my invention, together with others inherent in the same, are attained by the mechanism illustrated in the following drawings, the same being a preferred exemplary form of embodiment of my invention, throughout which drawings like reference numerals indicate like parts:
Figure l is a view in front elevation of my plating apparatus with a crankshaft, the center portion of which has been broken away, in operative position therein and showing a tank in section;
Fig. 2 is a View in end elevation with parts shown 4in section taken substantially on broken line 2--2 of Fig. 1, and in addition only one anode operating on a connecting rod bearing journal is shown for purposes of more clearly illustrating the invention;
Fig. 3 is a detached plan View of an anode connector linkage means shown in Figs. 1 and 2 of the drawings;
Fig. 4 is a sectional View, with parts in elevation, taken substantially on broken line 4 4 of Fig. l, on a larger scale than Fig. 1, and with the anode stem connector means broken away;
Fig. 5 is a view taken substantially on broken line 5-5 of Fig. 4 and with the bearing journal omitted;
Fig. 6 is a view taken substantiallyon broken line '6--6 of Fig. 4; and
Fig. '7 is a fragmentary perspective of a portion of the anode and particularly an end portion thereof.
Referring to the drawings a tank Hl is provided to contain the electrolyte to be used, such as one from which hard chromium may be plated on the cathode. Also, the remainder of the @genauso posed and the lower -end of -eachil-i's'fconnected' to a cross support opstand-I4, Which--fagain may be an anglev ironas shown. Theff'spaeing-between vertical supports i I3 "siadjustabletof-pcrmit crankshafts yof '*iiariusle'iig'ths'ltoflbprocpose is tov employ aftielrodiI'Eiliavingrightand left hand threadsatits respeetiveleiiisfithreads in the stands I4 'andin'-thevertioasiipportsiIf3, and nut means I6. Thus,'-byiturningimovement of the tie rod in one' directionthevertcalsup-;
ports I 3 are moved ftow'arld @each other and-by angular movement of Ithe'tie rodfI-'Eiiinfthe'iopposite direction the' vertical -supportsf'ifare moved away from each other. .Thefverticalfsupports i3 are held in.'spaced'relationfromfeach other at their upper en'd' portion '1byan` an'gle iron Il. Preferably Ithef a'ngleiron'y I'Ifhas a-plurality of adjusting holes I8;'-showniftoftheriight in 1Eig. 1, so that upon'insertin'g" bolts in'tthe proper holes in securing-supports1|`3 f-tofangle iron Il, the eiective length -of thefangl'efiron I'I between supports I3 vmay be adjusteddnf accordance with the size of the crankshaftfbeing-'processed. Also, the connecting means tI2- is `preferably carried by the angle iron f lllandsthez-fpostion of the supportI Iz'longitudinallyof the :angle iron I 'l is such to'provide'substantially 'alcalance so that only one'supportneed'bevemployed in moving the apparatus intof orfo-ut of 'the-tank Ii). Also, the framework comprisingsupportsry I3, tie rod I5, and angle iron-'I1' areapreferablyconnected to the cathode so that `by*:rneansd'iereinafter described the crankshaftftofhavef-itsEj-ournals plated will be the'cathoderin the'electrolysis process.
An electric motorfI lmay serve-as 'a-prime mover to rotate the crankshaft-during'plating. In order to provide desired speed'lof' rotation of the crankshaft, preferably aspeed reduction device 2U connects between 'electric 'motcrISland power output shaftfZI. Powerrfoutputshaf-tl carries sprocket' means` Y22 on which fis 'mounted chain drive 23. Chain 23-isf=mountedyonand drives sprocket 24.
A crankshaft mounting-and 'centeringchuck= Inmrderftoiprocess a erankshafuinrst, *werden *al' similar -fchuck 32 islmountedronlthe therieh'd.
The fonly difference #between the str-instureni desf :.ignated': generally by fazf fan-d 4fthef-1cranksnift "i mounting and `centering Schuck? xl24-1'45226327 is that` the'l latter carrieslthe l sprocket zhwh-lle the former has v*merely a platel-or-f-inptherwors only the-latter provides forlthepowertorrotte f the "crankshaft l3 I vvwhich `need be" accomplished lset screws 226 in f bosses 527l in'theichucksatdthe l `'respective y'ends of lthe crankshaft lGare adjusted so that the centering devices are the--'erteri'f the :crankshaft .or, 1in 1 otherA words; the-'reenter .Y about v`1 .which the` main-1'bearing-'journals 3330i the crankshaft "wereE formed. After @the ranklshaft 3I ha's the :centering 'devices`'1rniii'iteclfiat f its respective lv ends, vthetie 'rod I 5 'llanzdr'iframe La particular '-crankshaft, lthe fnutl'means'll s'creWsZ-S, as the line of centenoffthelcranlsliiiit.
In.ordertocontrol the currentIdensitydal d'in turn f' the :extent :of chromium:platingfon VJthe journals of the crankshaft, `I femployfthefferankshaft as the cathodeiin the electrolysisr-proc'ess- Thev electrical energy connected` to 'fthe-frame means I3 will-beA transferred Viaf-'Lthe.centring means vat i each endr i of :the crankshaftfitoithe crankshaft and yalso energy.y will .belltransmitt'ed by way ofthe chairr'drivel235as-thecathodezisithe ygrounded part of"=the lsystemwan'd.allfofithe groundedparts are interconnected.
vReferring to the anode-'circuitiazvibalilfuis provided which is insulated from theframeffor groundedtpartof the mechanism.' Thisfmayibe accomplished -by i mounting .bar 134 on'itwo' iinsulationstripsf35. I desire toiprovidean'ianode in close proximity to each bearingajournalwheh is to be'plated to controlcurrent density .and
lextent of plating. Thus, I provide-a :connector block 3Iv having anfopening-into'which is insertcomprises lugs or bosses Y21A carriedcbysprocket y 24. Stud bolts 25 maybe-employed to connect bosses 21 with sprocket24. -A-f-plurali-ty, asfthree, centering means are employed vwhich maybenn the nature of set screws 26 which arefthread'e'dly..
mounted in the bosses -Z'Iandprotrude to engage the circular periphery-of.'they crankshaft or a fiange carried thereby. Y
vIn order to eliminate any-weapon the lathe centers or conical depressions-vattheends'vofL the crankshaft beingprocessed. yavi-'em'aval'ole center or bearing 28 is provided.v a/Such-fmember is rigidly secured to sprocket-24, asyby being press iitted into arecess'thereinffandehas a tapered centering bearing for-receiving-iset screw` 70.
36 and 39. v
ed=a portion of' the anode bar 34 an'dafsetscrew 31 to thus provide detachable andfpositivec'on- Tand rigidlyVVV connect'- the block `39 with :i affrodifor anode connector stemv 42.
`AYReferring to Figs.y 4 to 'Tof the .-dr-awingsazeach -rod 'orl stem 42 is 'connected' with-fan'iarcuate `shaped anode- 43 which is fpositionedfcin relatively close spaced relation to a journal onaalcrankshat as: a connecting rod bearing-l jo'urnal'f- 44.1.?.Bynpro-- y-viding` an anode 43 of conformingan'di matching shape irr-close proximity as by aspace indicated 65.'
.. journal 44, substantially all'of the lelectroe-plating by 45 in Fig. 4, to a'connecting''rodbeardng :action 'will occur yon the connecting :'rodbbeaein "journa144. v
:Aiplurality of openings' '01'1 perforationsfiar provided in the normal upperv'surfacei of yreach anode f 43 thus'fpermittinglthe upwardfescapewf liberated-.gases therethroughwhich -arefgeneizated cartaceo Vplating so the. area of such openings may be rather liberal to insure rapid escape of the gases.
' f In order to provide electrical connecting means between the anode bar 34 and the anode 43 which Will vary suliiciently in length so that the anode 43 can follow a revolving connecting rod journal 44, I employ the link 40, pivotally mounted at both ends, and dispose the anode stem 42 at an vangle of substantially forty-five degrees to the vertical. Thus, as the anode 43 follows the connecting rod journals 44 as they revolve, the openings 46 will always be above the surface area of the journals 44 which are being plated and thus the gases generated during electroplating 'can `vreadily rise upwardly and` out through such openings.
f As lead anodes are less affected by the action 1 occurring during electro-chromium plating, preferably the anode 43 is formed of lead. As to I`the stem 42, the same may be shielded by means of shield 4l, which is a tube formed of any suit- `able non-conductor which will not be adversely alected by the electroplating bath, and thus the 'anode stem may be made of any suitable mate- -rial such as steel, 4stern 42 is formed of steel and is protected by 4a-shield such as 4l, the anode stem 42 should In the event that the anode be lead welded, as by weld 48, to the anode 43 so that any exposed steel portions of anode stem x42- Iwill be well up within the tube 4l. l though electrolyte will leak up in the tube 47 Even and adjacent the anode stem 42 there will be substantially no etching or dissolving occurring due to the effect of the shield 4T.
Referring in more detail to the construction and supporting means of the anode of Figs. 4 to 7,
inc., I employ two side shields 49. These may 'be formed of any suitable non-conducting plastic which will not be adversely affected by the electrolyte. These shields 49 are in the form of substantially one-half of an annular ring and each preferably has its lower edge portion tapered awayto form substantially sharp edge portions 50. These sharp edge portions 50 are designed to ride in close proximity to the corners or outside edges of a bearing journal so that the plating will be limited to the bearing journal by shielding andsubstantially no electro-plating will occur son the shoulders adjacent the bearing journals such as shoulders 5| of Fig. 6.
The side shields 49 are spaced from each other vand connected to the anode 43 by any suitable Ymeans which may include: four blocks 52 secured 'to 'side shields 49 .by means of screws 53; two scraper and anode positioning blocks 54; and
and the anode and thereby control the current density so that there will be the desired plating at the ends of the connecting rod bearing journals 44 which are adjacent the shoulders 5|, yet I prefer to shape the end portion of each anode 43 as is best shown in Fig. 7 of the drawings. This requires a less critical relation loe-` tween the shields and the cathode 44. Each end of the anode 43 has two cuts in aline circumferentially of the anode 43 and the portions -56 are bent laterally leaving V-shaped slots 5l and the portions 54 are further bent radially inwardly toward the connecting rod bearing journals 44.
Thus, the portions 56 are in closer proximity to is an increase of current density at such locations and Vinsurance is provided so that there will be proper plating of the journals 44 and particularly in the corners adjacent the shoulders 5|.
In operating the structure of this invention, firstv a crankshaft 3| is mounted for rotation on the centering chucks riding 0n 28 and 29 at its respective ends. Exact precision mounting of the crankshaft on such centers is not essential as the anode means will follow the journal to be plated eventhough the crankshaft is not precisely centered. Also, due to the fact that a chain drive is employed so that there can be sulcient slackness, failure to precisely center the crankshaft 3| will -not bring adverse results. Then an anode 43 with the parts connected therewith is connected to the anode bar 34 so that one anode is provided for each journal which is to be plated, whether the journal is a connecting rod bearing journal or a main bearing journal. As the blocks 36 are detachably connected with the anode bar 34 suitable spacing can be readily obtained so that the anodes 43 are aligned with the journal which is to be plated by the particular anode 43 involved.
`Next, current is permitted to flow between the cathode and the anode and at the same time the crankshaft 3| is rotated so there will be relative rotary motion between each anode and the journal which such anode is plating. My experience indcates that the speed of rotation of the crankshaft is not critical and may be over a substantially wide range with satisfactory results. However, I desire that the crankshaft shall rotate at relatively lower speeds as such lower speeds give less wear on the equipment as the wear increases with the speed of rotation of the crankshaft. Also, preferably the anode stem l2 is angularly disposed toward the crankshaft 3| and the crankshaft 3| is rotated in the direction of the arrows of Figs. 2 and 4 so that if an anode stem and the anode connected therewith should not follow a connecting rod bearing journal which is being plated, then the anode stem 42 and the anode connected therewith will swing to the right of the showing in Fig. 2 of the drawings and thus eliminate a possibility of a short circuit between an anode and the connecting rod journal which will be the cathode which was being plated. Also, the insulated portions 49 and 41 will prevent short circuiting to tank i3. In the event of arcing between an anode and a connecting rod journal, there will be burning at the point of the short circuit and if a journal is burned by an electric current, the journal tends to harden locally at the point of burning. Any bearing which has some part harder than the others, such as due to burning, will have very limited utility in that the wear and friction involved in a bearing and ajournal of such character will be non-uniform and the journal may not be successfully ground. Also, by providing an anode connection means which comprises the link means 48 and the anode Stem 42 which are angularly disposed as respects each other, I provide for suilicient extensibility and shortening of the length of the anode connection so that the anode may follow a revolving member such as a connecting rod bearing journal.
One of the most important features in control of chromium plating is control of current density. By current density is meant the density of amperes per square inch of cathode to be plated.
9i. Current pdensity control-fis ip erhaps* more impor?v tant*in` chromiumM plating: than in4 most' other types `of plating,V because the depositionwof. chromium in quantityV is not "directlypjproportonal. to the changes'in currentdensity, that'is,yif"the current density is doubledwe willnoth'ave two times the 'amount'of 'chromium deposited perunit of time. and the amount 'of chromium deposited by doubling the current densityV will'b'e closerto three times.
change the current densityand 'similarly the vcurrentdensity in the centerlof.the..space.between.
the anode and the .cathode .will'lbe different. from thecurrent density at the edges between the same Y.
cathode andthe anode unless.. provision. .ismade to increase .the current density. at .the edges.. A theory which will. probablyy explainwhythe current .density in the. center, of.. the space-r between an anodeand cathodeis dinerent .than the current.. densityatthe outer edges is that in thecenter the current travels in..a. path. directly between the cathodeandthefanode and vdoes -not tend to fan out.. whereas -on-theedges, the current tends to fan. around thecorners andfollowszother paths so there is not the.concentratedfcurrent density between theJ cathode and the-anodev because of such phenomenon. Therefore,` I have-provided.
side* shields 49 whichntend to limit the path of the current and therefore the amount of current which tends to `fan. out and'pass between the anode 43 andsome other part ofthe crankshaft functioning'as a cathode. In addition I have provided the edge portions 5S of the anode 43 which are closer to thefcornerszbetween-.thejournal 44 and the shoulders 5I than the anode'43 is to the-center portions. of the journal 44.
While it is-not critical thatther anoder43-be spaced fa. predetermined :definite amount, from# ajournalv 44," in practice I have foundithat thespacing-45 of Fig. 4 may be approximately one-@quarter of any inch and that the spacing of the portionst` from the journal 44 may be approximately-'three thirty-seconds of an inch.
While the principal function of bars 54 is to positively control` thespacingobetween anode 43 and the-cathode being plated; other phenomena. seem present. The gasesffrising,` which `are, liberated during electrolysis'shuntlo part for. decrease current ow therethrough yand thus .locally decrease the current density, vandfthereforeresult in a-lighter plating at-locationsonthe cathode separated from the anode by such gases. As gas is liberated the bubbles rise and pass out through opening 46 and if they tend to adhere to the cathode 44 they appear to be scraped 01T by scraper bars 54. Thus, I overcome any tendency of the liberated gas from interfering with the current density and providing non-uniform plating. In addition to the liberated gases interfering with the current density, I have found that the chromium as deposited appears to interfere with current density. In other words, particles or threads of chromium as deposited decrease, at such location, the space between the anode and the cathode and which increases the current density and tends to further build up local areas. Bars 54 appear to scrape oi and smooth down almost immediately the various threads of chro mium as they are formed and any high points so that I am able to maintain uniform current density and uniform plating without interference by reason of the chromium which is being deposited. While said plating may be obtained without a Any changein the distance ofthe. spacingbetween .the anode andthe cathode .willi 5= plating, becomes a function ofjtime so that'by employing a standard ampere flow between the cathode and the anode, cathode. structures of uniform sizes and proportions, andfmaintainin'g other conditions uniform,v Ijam: able to determine.
^`by a time interval alone the exact quantity ofl chromium which is. being plated.. andw-ithin ten. percent (10%) tolerances in. commercialgop'eraf.4
Another feature which enters into .uniformcurrent density' and uniform. plating .involves the vuse of substantially .the same character of .electrolyte between eachanode and the cathode to be plated..
This maybe accomplished 'by adequate circula. tion .of the solution so that the density of the Aelectrolyte between each anode" and its mating .,cath.- ode is substantially the same. I 'have discovered.
that the revolving. connecting rodfbearing jour: nals function .as a circulating means and provide suiiicient circulation of the Yelectrolyte without the addition of further. means.
Thus, in my process .I provide for the electroplating-of cylindrical Ishaped bodies, such as' the main and-connecting rodbearing journalszof a crankshaft. In'suchV processzthe surface to` be --plated'functi0ns as thecathode in an electro,-
plating process.Y Next; I provide an arcuate shapedfan'odein' the electro-plating bath'which is disposed'. in relatively closel spaced v'relation to the cathode As ameans of providing substantial;y
ly uniformcurrent ydensitybetween operative sur.-
faces of 'thecathode-and'1the"anode;-first; Iniay employ an anode where the central portionis sub*- stantiallyinA uniform spaced;I relation*y from the cathode Vand the' side' portions. ofl the anodeare 10 in closerspaced relation'to the cathodethanrthe' central j portion of the-"anode vis to 'such' cathode. Second; Imayemployshielding means so that 'the pathof -ow of "currentis ulimited-to 'substantially between-the cathode to-- be plated and theanode.
OLI-provide acombination-ofthe-two; Preferably, the'anode is provided: withl a" plurality of" openings so that `gas vliberated -during `electrolysis may rise throughsuch'openings. Also, I'provide a spacerfmember so that'` there vis substantially uniform space-"relation betweenithe'cathode and.
the anode; Suclry spacermember' is preferably a combined spacer and scraper 'member so'that as. the 'cathode' is' beingY rotatedv orrevolved; the4 spacer member will continuously during plating rub and scrape the surface of the cathode. This results in the removal of gas bubbles which tend to adhere to the cathode and further dressingly polishes the cathode during plating and thus eliminates any high spots or spots closer to the anode which would disturb the current density at such location. The electrical connection means between the source of anode current and the anode is preferably in the form of pivotally interconnected link means so that sufficient change in the effective length of such electrical conductor may be had to compensate for the plating of a rotating or revolving surface. By reason of this connection and by reason of the weight of the anode means, which includes lead member 43, the anode means is adapted, by the pivotally interconnected link 4l), to be urged toward the portion of the crankshaft being plated, and the scraper members 54 ride on and scrape the bearing 44 being plated. Also the link which connects directly to the anode is at an angle so the anode will fall clear of the cathode, if accidentally released, thus preventing short circuiting to the cathode. Also, preferably I provide detachable chucks providing bearing support on which the crankshaft may be rotated and thus any wear on the bearings due to the electrolysis will be had on replaceable bearings and not on the crankshaft proper.
Obviously, changes may be made in the forms, dimensions, and arrangement of the parts of my invention, without departing from the principle thereof, the above setting forth only a preferred form of embodiment.
1. Apparatus or electro-plating the main and connecting rod bearing journals of a crankshaft which comprises a tank containing an electroplating bath in which the crankshaft is submerged; means connecting the crankshaft with a cathode; means for rotating the crankshaft in the electro-plating bath; and an anode means slidingly mounted on and urged toward the journal surface of the crankshaft being plated, said anode means comprising an arcuate shaped anode, having its center portion in one circular path and its side portions bent radially inwardly therefrom at their ends, pivotally interconnected and angularly disposed link means connected at one end to a fixed support and at the other end to the anode and connecting the anode with a source of anode current, non-conductor means slidingly contacting and rubbing the journal surface being plated and supporting the anode in spaced relation thereon, and shielding means at the ends of the anode, extending inwardly toward the journal being plated, and limiting the path of current flow there past.
2. Apparatus for electro-plating the main and connecting rod bearing journals of a crankshaft Which comprises a tank containing an electroplating bath in which the crankshaft is submerged; means connecting the crankshaft with a cathode; means for rotating the crankshaft in the electroplating bath; and an anode means slidingly mounted on and urged toward the journal surface of the crankshaft being plated, said anode means comprising an arcuate shaped anode having a plurality of gas escape openings therein, pivotally interconnected and angularly disposed link means connected at one end to a fixed support and at the other end to the anode and connecting the anode with a source of anode current, non-conductor means slidingly contacting and rubbing the journal surface being lplated and supporting the anode in spaced relation thereon, and shielding means at the ends of the anode, extending inwardly toward the journal being plated, and limiting the path of current flow there past.
3. Apparatus for electro-plating the main and connecting rod bearing journals of a crankshaft which comprises a tank containing an electroplating bath in which the crankshaft is submerged; chuck means disposable on the respective ends of the crankshaft, each said chuck means having bearing means alignable with the center of rotation of the crankshaft; means connecting the crankshaft with a cathode; means for rotating the crank shaft in the electro-plating bath; and an anode means slidably mounted on and urged toward the journal surface of the crankshaft being plated, said anode means comprising an arcuate shaped anode, pivotally interconnected and angularly disposed link means connected at one end to a fixed support and at A the other end to the anode and connecting the anode with a source of anode current, non-conductor means slidingly contacting the journal surface being plated and supporting the anode in spaced relation thereon, and shielding means at the ends of the anode, extending inwardly toward the journal being plated, and limiting the path of current flow there past.
GEORGE E. MILLARD.
'REFERENCES CITED The following references are of record in the le of this patent: l
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|U.S. Classification||204/212, 205/115, 204/260, 205/97, 204/DIG.700, 205/93, 204/224.00R, 205/131, 204/285|
|Cooperative Classification||Y10S204/07, C25D7/00|