US2406956A - Apparatus for electroplating of bearing shells - Google Patents

Description

Sept. 3, 1946.

c. F. MATTHEWS 2,406,956

APPARATUS FOR ELECTR OPLATING 0F BEARING SHELLS Fi-led Oct. 27,,1942 2 She ets-Sheet 1 2 I v I 5/? iE=- I02 1 I02 m4 Ininentor Sept. 3, 1946.-

C. F. MATTHEWS APPARATUS FOR ELECTROPLATING OF BEA RING SHELLS Filed 001;. 27 1942 2 Sheets-$heet 2.

Snventor (lttotnegs .ings are shown in Patented Sept. 3, 1946 APPARATUS FOR ELECTROlLATI NG BEARING SHELLS Carroll F. Matthews, Indianapolis, Ind., assig'nor to General Motors Corporation, Detroit, Mich;, a corporation of Delaware Application October 27, 1942, Serial No. 463,484

Thisinvention relates to. theart of plating by the application of George A. Zink and Carroll F. ,Matthews Serial Number 350,016, filed August 2, 1940 forBearing and method of'making same.

In the prior application mentioned, apparatus is disclosed to plate but a single bearing, while in the instant application the apparatus will plate ,two or more bearings simultaneously in the same bath. For purposes of illustration, three bearthe apparatus disclosed onthe drawings. i g

The manner of cleaning the bearing shell and preparing it with a copper coating preparatory to receiving the silver coating is described and claimed in the copending application mentioned in the foregoing.

The improvement in the instant application relates to a fixture immersed-in a container having the electrolytic bath. The fixture comprises an upright propeller tube at the bottom of which there is applieda marine impeller driven by an electric motor suspended outside of and over the container. The bottom of the tube has connected thereto a plurality of pipes (three in the present instance) which radiate therefrom in a single plane. The pipes are turned upwardly at their ends, and at the end of the upturned part there is mounted the apparatus for plating the bearing shells with silver.

The impeller at the bottom of the tube forces the electrolytic solution through the pipes and through a'plug having spiral slots at its edge. The liquid is forced through the spiral slots and into the cathode containing the bearing shells. The spiral slots will give a slight spinning motion to the liquid and cause it to spin or whirl around and continue to circulate as it is moved upwardlypast the bearing shell by themotion given to the liquid by the impeller.

The anode comprises a hollow perforated stationary hard rubber tube mounted inside the cathode and having a fabric (muslin, glass, or the like) wound thereabout, the fabric, however, being pervious to the liquid and enabling the passageof the silver ions to the cathode. The hollow perforated anode tube is secured to a metal anode plug, and to a central bore in the plug a smaller metal tube issecured; Ifhe anode (comprising the rubber tube, the metal tube and the plug) is removable and the space between the 55 bevel being to receive a corresponding beveled 10 Claims. (01; 2o4j-272) Y two tubes is filled with suitable silverballspr chunks of silver to replenish the silver deposited from the liquid'by'theelectrolytic action. On the drawingsi T Figural is a perspective view of the electrolytic bath with the apparatus mounted therein, apart of the container being broken away better tojillustrate the apparatus. u

Figure 2 isan enlarged detailed sectional view through one of the elements of the apparatus and showing the propeller tube partly broken away to illustrate the application of the impeller.

Figure 3 is a section on theli'ne 3-3 of Figure 2. I

On the drawings, the numeralz indicates the tub or bath in which the .electrolyte is contained. This bath is positioned below a-frame (not shown) on which there is mounted an electric motor (not shown) whichdrives a shaft 4. At the end of the shaft there is connected a marine impeller 6 which is mounted at the lower part in of an upright propeller-tubelZ, the top of which is below the level of the electrolytic solution. The tube l2 has suitably connected at its lower end the radiatingtubes l4, l6, and l8, the outer ends ofwhichare upturned as indicated at 20,- 22, and 24. Where the upturned ends 20., 22, and 24 join onto the main tubes the joint is flattened at 26 to form a. baille, the purpose of which is to cause the liquid to move more evenly or smoothly upwardly in the end 20, 22, and 24. At the upper part of each upturned tubue larend 20, 22, and 24, locating rings or plates 28, 30, and 32 are secured. I i

The propeller tube 12 and the pipes l4, l6 and I8 are welded as at :3l to a frame 33 formed of four strips of metal placed at right anglesto each other to form a square with the ends of the strips projecting beyond the square, asshown.

This frame is not secured to the bottom of the container but rests freely thereon to enable the ready removal of the frame and the apparatus.

At the top of each upturned part 20, 22, or 24,

an electroplating assembly is mounted, and as 3 part of a mask fixture MF shown in detail in Figure 2. A cone 4-5 at the bottom of the plug 38 directs the flow of solution into the spirals 40 and reduces resistance to free flow of solution.

The spiral spray plug 48 has a recess 43 at its upper part and in the recess there is mounted the metalliclcontactor spray plug 44 gthreadedlyconnected as at 46 to a contact rod 48 covered with a rubber tubing 50. The contact rod 48 extends upwardly out of the solution as best indicated in Figure 1.

Over the contact 44 there is removably positioned a metal anode plug 52, the lower part of which is in the recess 43 in;the. spiral,sprayplug 38 and the upper part 53 of which projects outwardly over the top surface of the plug. The top outwardly projecting part 53 isreduced -as indicated at 54, and over this reduced, part there is received the hollow perforated hard rubber anode tube 56. The tube 56 is secured to the anodeplug 52gbymeans ofthe pins 58. Thespiral spray 38,- thespray plug-44 and the anode plug52'have aborethrough-which there passes a coldrolled steel rod 68,-the' up er end H of which projectsbeyond-thetop of the rubber anode-56.

A -steel-tube -62 surrounds--the rodfilland extends downwardly into and is -secured=inthe1bore of the anode plug 52 and -its' bottom restson the spray 'plug -44 immediately adjacent the bore in the-plug. Thetopof the tubing-'82 also extends-beyondthe top of the anode 56.

The anode tube 56 is purposely made hollow in order that it may receive a plurality of balls or chunks of silver--53"to-replenish the silver which isremoved from the bathinthe electrolytic-process. Preferably, the anode-tube 56-has wound therearounda suitable fabric- 65, preferablymuslin, which is not attacked "by the solution but which-is pervious-w the electrolyte.

The anode comprising "the perforated rubber tube 56, the-fabric 55 wound thereaboutpthe meb alconductinggtube 6-2, and the anode plug -52 are secured together and-removable from the apparatus as a unit. *The reason for the removability' is to enable the anode to be cleaned, to replace the fabric- 65 "changing the anode size for difierentsize bearings'etc.

T-he maskfixtu-re which contains the hearing 'shells to be silver plated, and -whichcomprises the cathode of the apparatus, is shown in detail iii-Figure 2. The bottomot themask fixture-is formed-of-a'ring of metal-64 overwhich there is positionedaring-shaped molded rubber mask 66. The mask-' 66"=has-an interior shoulder 68 -on-whi chthere isadapted toseat two of the bearingshells Ill-which are to be-electroplated. ThisinaskBB-is also-- provided with a reduced upwardly -proj ecting part '12,--the-purpose of which will be-laterdescribed.

Atoneside ofthemask 66'there is a bore 14 through which there passes a-wire or rodlfi which forms an electriccontact. The innerend 1180f this rod isincontact with "the outer .surface of 'This mask 88 has a shoulder 98 to receive the .upperwend of the bearing shells 10a. The mask J88..likewise has a bore 92 to receive a wire or rod v94 forming aneIectrical conductor. The end 96 ,of therod184i is in contact with the upper bear- .515 jingqshells illlmwhile the outer end extends upwardly out of the liquid and is connected to one "or the leads-(not shown) through which the current passes back to the source.

Both contact rods 16 and 94 are covered exteriorly with a rubber-tubing indicated at 98,

and bothare retainedon' the masking fixture ME by the retainer -99.

"Gverthe' top of the mask "88 a -metal ring I00 is mounted. -'The-ring-|88 is provided with suitable lateral openings and the ring -at the' bottom is provided with similar -mating openings. Preferably there are-two openings I to each r-ing located 180 apart. "Through-theopening-s there pass the-retaining -rods 182, each having a -'-pin 1 Mitherethroughat its upper end,-an'd'- this pin strikes against the :upper surface 'of'the L ring 00 while a 'nut' H! S ls :screwed onto the 1 lower" end of the --r ods and-tightlyholds theassembly-"together.

In order to prevent the silver in the eleotro- -85 lyte-from being "deposited on theoutsideof 'the bearing shell, both bearing shells 18 andi'lza are covered by -an-outer mask 38 composed of suitable-nonconducting-material such-as rubber. "This mask" l'08"-fits at-one -end over the projecting-mart -1 2 of 'thelower rubber mask GS-and at -its'upper end over the projecting part H0 0f the upper rubber-mask.

Theassembly-MFas-showu in -Figure-Z ispositioned around the -anode'56 and when "in position the beveled or -chamfere'd'part I2-of :the lower ring '64-fits over 'the beveled or cham'feredpart 42 on'the spray shell 34 tightly -to"hold theassembly l\/F'on the spray shell.

The :current coming from any suitable source will enter thr-ough the lead rod '48, pass to the spray plug'-4'4,"t-he anode plug 52,the-ro'd 6-2, and then 1 into the --electrolytic solution. It will then pass-'through-the solution across-to the walls of the shells l8 and 10a and from-the shells through theeonducting' rods-J-Band-M out of'the solution and backito thesource. 'Thecurrent inlpassing from the anodeto thecathodaacross.the electrolyte will'cause the silverin the solution to vdeposit on the interior ofthe. shells 10 and'10a.

During' the operation of the electrolytic; process; the impeller 6 at the bottom -of;thepropeller tube 12 will force thesolution through the tubes [4, I 6, and 5 I 8 and .out through-the spiral ;passages 40 to cause it to pass slowly upward in 1a the bearing shell Ill--while-the outer end of the slight swirlingway-D the inner ces of the rod 16 extends upwardlyoutof the solution and is adapted to contact with one of -the leads not shown) through-whichthecurrent passes backto the source. The bearing shells 10-are in contactwith each other at-theirparting lines 8!,

'At' the top ofthe bearingshells 18 a molded rubber ring 82 is positioned, a-nd on-top of the ring' 82 asecond pair of bearing shellsi'lUa, similar to the shells I0, are'positioned. An outer bearing shells m: and 18a 1 and. toward'the itop :of the anode tube 56. "The solution .will spill over the top of *theanode and into the bath in the container 2 and be recirculatedby the impeller.

This process will continue until the desired amount of silverhas been deposited on'the interior-oftheshells-"lfl and 12.

As fast as the silver is depositedfrom thesolution by the electrolytic "process, the solution will steel ring "84 "is positioned across .thetwo's'hells dissolve additional replacement silver from-the silver balls or chunks 63 inside the anode; In this way the amount of silver in solution is kept substantially constant. it 1 Referring to Figures 1 and.2, it will be noted that a bafile B has been secured inside the propeller tube l2. The purpose of this baffle is to prevent the swirling of the liquid in the tube and to enable itto. pass down in a smooth and quiet way to theimpeller 6. The baffle B is not sure ficiently wide to prevent the impelleri and its shaft 4 from being withdrawn from the tube I2.

On the drawings the invention is disclosed-as appliedto three units or masking fixtures each fixture having two sets .(10, I and a, 10a) of bearing shells. The invention is capable of adaptation to two, four or more masking fixtures, each of which may use one, two or more sets of bearing shells, the application of the invention being limited only by practical or mechanical limitations. For. example, the propeller tube may be placed at thev center of four pipes which radiate from the propeller tube 90. apart and at whose upturned ends masking fixtures and anodes are mounted. r

If desired, the rubber spiral spray plug 38 may be eliminated and the electrolyte caused to flow upwardly between the anode and the cathode without imparting thereto any swirling motion. In case the spiral spray plug 38 is not used, the contact plug 44 can be supported by the rod 48 alone or by insulated arms positioned under the plug 44 and having their ends secured -to the inside wall of the shell 34.

When the desired amount of silver has been plated on the bearing shells, the cathode or masking fixture MP is removed from thebath by lifting it upwardly over the anode and out of the solution. The rods I02 are now released to enable the masking fixture to be taken apart, the plated shells are removed, and unplated shells are placed in the fixture. The masking fixture can now be reapplied and the plating process recommenced to plate the new shells.

When it is desired to clean or change the anode, the unit comprising the perforated rubber tube 56, the metal tube 62 and the plug 52, is removed. The anode can now be taken apart by removing the covering 85 of fabric and then removing the pins 58 to enable the rubber tube to be separated.

I claim:

1. In an apparatus for electroplating the bearing shells of bearings of crankshafts used on internal combustion engines, a container having an electrolytic solution therein, an assembly fixture comprising a tube having a plurality of pipes connected thereto and extending therefrom, said assembly fixture being immersed in the electrolytic solution, an anode mounted on the end of each pipe, a cathode mounted on the end of each pipe and surrounding the anode in spaced relation, said cathodes comprising bearing shells, means to circulate the electrolytic solution from the tube into the pipes and into the space between the anode and cathode, and means to conduct an electric current through the anodes and cathodes and across the electrolyte to cause a deposit of metal from the electrolyte on the bearing surface of the bearing shells.

2. The invention of claim 1, the end of each pipe having a plug mounted therein, and a spiral passage in the plugs to give the liquid a slightly swirling motion as it passes upwardly in the space 7 between the anodes and cathodes.

3. In an apparatus for electroplating the bearing shells of bearings of crankshafts used on in- 6 ternal combustion engines, a container having an electrolytic solution therein, an assembly fixture comprising a tube having a plurality of pipes .connected thereto and extending therefrom, said assembly fixture, being immersed in the electrolytic solution,,an anode mounted on the end of each pipe, a cathode mounted on the end of each pipe and surrounding the anode in spaced relation, said cathodes comprising a plurality of pairs of bearing shells, means to space each pair of shells from the adjacent pair of shells, an im peller in thetube to circulate the electrolytic solution from the tube into the pipes and into the space between the anode and ,cathode, r and means to conduct an electric current through the anodes and cathodes and across the electrolyte to cause a deposit of metal from the elec-.- trolyte on the bearing surface of the bearing shells. V

4. In an apparatus for electroplating the bear-. ing shells of bearings of crankshafts used on internal combustion engines, a containerhaving an electrolytic solution therein, an assembly fixture comprising a tube having a plurality of pipes connected thereto andextending therefrom, said assembly fixture being immersed in the electrolytic solution, an anode mounted on the end of each pipe, a cathode mounted on the end of each pipe and surrounding the anode in' spaced relation, said cathodes comprising bearing shells and being removably positioned on the pipe ends to enable the removal and replacement of the bearing shells, means to circulate the electrolytic solution from the tube into the pipes and into the space between the anode and cathode, and means to conduct an electric current through the anode and cathode and across the electrolyte to cause a deposit of metal from the electrolyte on the bearing surface of the bearing shells.

5. In an apparatus for electroplating the bearing shells of bearings of crankshafts used on internal combustion engines, a container having an electrolytic solution therein, an assembly fixture comprising a tubehaving a plurality of pipes connected thereto and extending therefrom, said assembly fixture being immersed in the electro lytic solution, an anode mounted on the end of each pipe, a cathode mounted on the end of each pipe and surrounding the anode in spaced relation, said cathode comprising bearing shells, means embodied in the cathode to mask the outer surface and ends of the shells to prevent the plating of the outer surface and ends, means to circulate the electrolytic solution from the tube into the pipes and into thespace between the anode and cathode, and means to conduct an electric current through the anode and cathode and across the electrolyte to cause a deposit of metal from the electrolyte on the bearing surface of the bearing shells.

6. In a cathode apparatus for electroplating the bearing shells of bearings of crankshafts used on internal combustion engines, a mask, a pair of bearing half shells positioned on the end of the mask, a second pair of bearing half shells positioned adjacent the first shells, means spacing the second pair from the first pair of shells, a second mask positioned on the end of the second pair of shells, a cover of nonconducting material over the outside of the shells, means to hold the masks and shells in assembled relation, and current conducting leads mounted in the masks and connected with each pair of bearing shells.

7. In a cathode apparatus for electroplating the bearing shells of bearings or crankshafts used on :internal combustion engines, a .first mask, a second mask, a zpluralityof superimposed aligned pairs of bearing :half shells positioned Zbetween the masks and spacing them from each other, a cover of nonconduoting material over the outside of the shells, means removably to hold the masks and shells in assembled relation, current conducting leads mounted the masks and connected'wi-th the end pairs of bearing shells.

8. -In an apparatus for-electroplating thebearing shells ofbearingsof crankshafts used on internal combustion engines, =a'container l-1aving-an electrolytic solution therein, an assembly fixture comprising a tube and a pipe connected thereto andex-tendi-ng away therefrom, said assembly fixture being immersed in the electrolytic solution, an anode mounted on the end of the pipe, a cathode mounted on the endof'the pipe and surrounding the anode in spaced relation, said cathode comprising bearing shells, means in the tube to circulate the-electrolyticsolution from the tube into the pipe and into the space between the anode and cathode, and means to conduct an electric current through the anode and cathode and across the electrolyte to cause a deposit of ,8 metal from the electrolyte on :the bearing surface of :the bearing shells.

9. The invention of claim 8., said 'meansin'the tube to circulate the electrolytic solution comprising an impeller positioned inside the tube near the bottom thereof.

10. In an apparatus for electroplating the hear- .ing shells of bearings of crankshafts vused on internal combustion engines, a container :having an electrolytic solution therein, an assembly :fixture comprising a tube and a pipe connected thereto and extending away therefrom, said .assembly fixture being immersed in the electrolytic solution, a plug secured to the .end of the pipe, an anode mounted on the plug, :a cathode mounted on the :plug and surrounding the anode in spaced relation, said cathode comprising bearing :shells, means in the .tube to circulate the electrolytic solutionfrom the tube into the pipe and into the space between the anode andcathode, and means to conduct an electric current through the anode and cathode and across the electrolyte to cause a deposit of metal .from the electrolyte on the bearing surface of the bearing shells,

CARROLL F. MATTHEWS.

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