CA1323328C - Contact roller for electroplating fiber - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A contact roller comprising: (a) a removably mounted copper tube; (b) a first fixed bearing; (c) a bushing mounted on the fixed bearing having an outside diameter equal to the inside diameter of the copper tube; (d) a second fixed bearing mount in alignment with the first bearing mount; (e) a bushing mounted on the second fixed bearing mount, said bushing having the same outside diameter as the bushing mounted on the first fixed bearing; and (f) means for translating the bushing mounted on the first fixed bearing horizontally to release the copper tube.
Such a contact roller may be employed in a process and apparatus for tensioning fiber during electrodeposition of a metal layer in a continuous process.

Description

TlllS AppllCat1011 i9 a dlvlslollal of applicatlon No.
~1~7,19' filed on Julle 22, 1~8~, llOW Canadlarl ~atent 1,253,455.
FIELD OF THE INVENTION
This inventlon relates to contact rollers useful ln a process and an apparatus for the contlnuous production of metal coated filaments.
D~SCRIPTION OF THE PRIOR ART
Filaments comprising non-metals and serni-metals, such as carbon, boron, sllicon carbide, polyester, nylon, aramid, cotton, rayon, and the like, in the form of monofilaments, yarns, tows, mats, cloths and chopped strands are known to be useful in re-inforcing metals and organic polymeric materials. Articles com-prising metals or plastics reinforced with such fibers find wide-spread use in replacing heavier components made up of lower strength conventional materlals such as aluminum, steel, titanium, vinyl polymers, nylons, polyester, etc., in aircraft, automobiles, office equipment, sportlng goods, and in many other fields.
A common problem in the use of such filaments, and also glass, asbestos and others, is a seemlng lack of abllity to trans-late the properties of the hlgh strength fllaments to the materlalto whlch ultlmate and intimate contact ls to be made. In essence, even though a high strength filament ls employed, the fllaments are merely mechanically entrapped, and the resulting composite pulls apart or breaks at disappointingly low applled forces.
The problems have been overcome in part by depositing a layer or layers of metals on the indlvldual filaments prior to q~

.

- 2 ~ 1323328 incorporating them into the bonding material, e.g., metal or plastic. Metal deposition has been accomplished by vacuum deposition, e.g., the nickel on fibers as described in United States patent No. 4,132,828; and by electroless deposition from chemical baths, e.g., nickel on graphite filaments as described in United States patent No. 3,894,677; and by electrodeposition, e.g., the nickel electroplating on carbon fibers as described in Sara, United States patent No. 3,622,283 and in Sara, United States patent No. 3,807,996. When the metal coated filaments of such procedures are twisted or sharply bent, a very substantial quantity of the metal flakes off or falls off as a powder. When such metal coated filaments are used to reinforce either metals or polymers, the ability to resist compressive stress and tensile stress is much less than what would be expected from the rule of mixtures, and this is strongly suggestive that failure to efficiently reinforce is due to poor bonding between the filament and the metal coating.
It has now been discovered that if electroplating is selected and if an amount of voltage is selected and used in excess of that which is required to merely dissociate (reduce) the electrodepositable metal ion on the filament surface, a superior bond between filament and metal layer is produced. The strength is such that when the metal coated filament is sharply bent, the coating may fracture, but it will not peel away. More-over, continuous lengths of such metal coated filaments can be knotted and twisted without substantial loss of the metal to flakes or powder. High voltage is believed important to provide or facilitate uniform nucleation o~ the electrodepositable metal on the filament, and to overcome any screening or inhibiting effect of materials absorbed on the filament surface.
Although a quantity of electricity is required to electrodeposit metal on the filament surface, an increase in voltage to increase the amperes may cause the filaments to burn, which would interrupt a continuous process. The aforesaid Sara patent No. 3,807,966, uses a continuous process to nickel plate graphite yarn, but employs a platiny current of only 2.5 amperes, and long residence times, e.g., 14 minutes, and therefore low, and conventional voltages. In another continuous process, described in United Kingdom patent No. 1,272,777, the individual fibers in a bundle of fibers are electroplated without burning them up by passing the bundle through a jet of electrolyte carry-ing the plating material, the bundle being maintained at a negative potential relative to the electrolyte, in the case of silver on graphite, the potential between the anode and the fibers being a conventional 3 volts.
The invention of the parent application provides an efficient apparatus to facilitate increasing the potential between anode and the continuous filament cathode, since it is a key aspect of the present process to increase the voltage to obtain superior metal coated filaments. In addition, since it permits extra electrical energy to be introduced into the system without burning up the filaments, residence time is shortened, and production rates are vastly increased over those provided by the prior art. As will be clear from the detailed description which follows, novel means are used to provide high voltage plating, strategic cooling, efficient electrolyte-filament contact and high speed filament transport in various combinations, all of which result in enhancing the production rate and quality of metal coated filaments. Such filaments find substantial utility, for example, when incorporated into thermoplastic and thermoset molding compounds for aircraft lightning protection, EMI/RFI
shielding and other applications requiring electrical/thermal conductivity. They are also useful in high surface electrodes for electrolytic cells. Composites in which such filaments are aligned in a substantially parallel manner dispersed in a matrix of metal, e.g., nickel coated graphite in a lead or zinc matrix are characterized by light weight and superior resistance to compressive and tensile stress. The apparatus of this invention can also be employed to enhance the production rate and product quality when electroplating normally non-conductive continuous filaments, e.g., polyaramids or cotton, etc., if first an adherent electrically conductive inner layer is deposited, e.g., by chemical means, on the non-conductive filament.

SUM~ RY OF THE INVENTION
The present invention seeks to provide filaments formed of a conductive semi-metallic core with metallic coatings.
The present invention also seeks to provide a process in which the electroplating of the filaments is effected under high voltage electroplating conditions.
The present invention further seeks to provide a process and apparatus which will efficiently and rapidly coat filaments with metallic coatings and facilitate the cleaning and collecting of the finished product.

In accordance with the invention of the parent applica-tion, apparatus has been provided in which a plurality of filaments can be simultaneously plated efficiently with a metal surface and thereafter cleaned and reeled for use in a variety of end products.
According to the invention of the parent application, there is provided an apparatus for imposing tension on a continuous fiber being passed through a continuous processing operation comprising: means to pass the fiber at a determinable fixed speed through the continuous processing operation, said means being located upstream of said continuous processing operation; an array of tension rollers, around which the fiber passes in a mode reversing the direction of the path of the fiber, said array of tension rollers being located downstream of said continuous processing operation; and means to drive the array of tension rollers in the same direction as the fiber at variable speeds equal to or less than the speed of the fiber.
The apparatus is a continuous line provided generally with a pay-out assembly adapted to deliver a multiplicity of filamen.s to an electrolytic plating bath. The line includes a pre-treatment process, after which the metal-plating is performed in a continuous process by the passage of the clean fibers through an electrolyte under high voltage conditions. Means are provided to cool the filaments during the passage from the contact roll associated with the electrolytic tank and the electrolyte bath.
Further, the filaments pass over contact rollers into the electrolyte. The line includes an assembly of tensioning 6 ~1109-7296D
rollers that serve to lnsure a tlght dlrect llne of the fllaments from the contact roller to the electrolyte.
The lnven~lon of thls dlvlslonal appllcatlon comprlses a contact roller comprlslng: (a) a removably mounted copper tube;
(b) a flrst flxed bearlng; (c) a bushlng mounted on the flrst fixed bearing havlng an outslde diameter equal to the inside dia-meter of the copper tube; (d) a second flxed bearlng mounted ln allgnment wlth the flrst fixed bearlng; (e) a bushlng mounted on the second fixed bearing, said bushlng havlng the same outside diameter as the bushing mounted on the flrst flxed bearing; and (f) means for translatlng the bushlng mounted on the flrst flxed bearlng horlzontally to release the copper tube.
The tenslonlng rollers are comprlsed of a plurality of driven rollers over which the filaments pass, and the path of the filament is reversed to create tension. The tensioning rollers are driven independently of the drive for the processing apparatus and at a speed equal to or less than the speed of the filaments.
The speed is determlned by visual inspection.
The contact rollers are located in close proxi~lty to the surface of the electrolyte, and by virtue of the processing conditions require frequent change. As a result the contact rollers are mounted on fixed aligned mounts. The mounts both carry support bushlngs having an outside diameter equal to the inside diameter of the contact roller.
DESCRIPTION OF THE DRAWINGS
The invention will be more readily understood when viewed in association with the following drawings wherein:
Flgure 1 is a schematic view of the overa~l process of . .;

- 7 ~ 1323328 the subject continuous electrolytic plating process except for the pay-out assembly.
Figure 2 is an elevational view of the pay-out section arranged specifically to simultaneously deliver a multiplicity of fibers to the electrolytic plating operation.
Figure 3 is a plan view of the pay-out assembly of Figure 2.
Figure 4 is an isometric view of the wetting and tensioning rollers between the pay-out and electrolytic bath.
Figure 5 is an elevational view of one electrolytic tank.
Figure 6 is a plan view of the tank of Figure 5.
Figure 7 is a sectional elevational view through line 7-7 of Figure 5.
Figure 8 is an isometric view of the commutation fingers.
Figure 9 is an isometric view of one contact roller in association with the means for providing coolant to the fibers and a current carrying medium from the contact roller to the bath.

132~328 -- 8 -- .

FIGURE 10 is an elevational view of a section of the electrolytic tank depicting an anode basket.

FIGURE 11 is a schematic of the electrolytic coolant conductor and a contact roller.

FIGURE 12 is a sectional elevational view of a contact roller of the process assembly.

FIGURE 13 is a detail of the end cap of the roller of FIGURE 12.

FIGURE 14 is a partial detail of the opposite end of the roller of FIGURE 12.
FIGU~E 15 is a view of the electrical system of the present invention.

FIGURE :L6 is a drawing of the mechanism for synchronously driving the apparatus of the subject invention.

FIGURE 17 is a plan view through line 28-28 of the section of FIGU~E 16.
FIGURE 18 is a side elevational view of the roller assembly in the drying section of the system.

The process and apparatus are directed to providing an efficient and complete means for metal-plating non-metallic and semi-metallic fibers.
The process relies on the use of very high voltage and current to effect satisactory plating. As a result of the high voltage and current, an apparatus has been developed that can produce high volumes of plated material under high voltage conditions.
The process and the apparatus particularly suitable for practicing the process are described in the preferred embodiment in which the specified fiber to be plated is a carbon or graphite fiber and the plating metal is nickel. However, the process and apparatus are suitable for virtually the entire spectrum of metal-plating of non-metallic and semi-metallic fibers.
The overall process and schematic of the apparatus except for the pay-out assembly are generally shown in Figure 1.
The operative process includes in essence, a pay-out assembly for dispensing multiple fibers in parallel, tensioning rollers 6, a pre-treatment section 8, a plating facility 10, a rinsing station 12, a drying section 14 and take-up reels 16.
More particularly, the pre-treatment section 8 shown generally in Figure 1 includes a tri-sodium phosphate cleaning section 26 and an associated washing-tee 28, rinse section 30 and associated washing-tees 32 and 32A, a hydrochloric acid section 34 and associated tee 36, and rinse section 38 with associated washing-tees 40 and 40A. The plating facility 10 is comprised of a plurality of series arranged electrolyte tanks 13~28 shown illustratively in Figure 1 as tanks 18, 20, 22 and 24, each of which is charged with current by a separate rectifier, better seen in Figures 5 and 15. The rinsing section 12, sho~m generally in Figure 1, is comprised of tank and tee assemblies similar to the pre-treatment apparatus. An arrangement of cascading tanks 42 and tees 44, 44A and 44B cycle rinse solution of water and electrolyte over the fibers 2. Thereafter, clean water is passed over the fibers 2 in the rinse section 46 provided with tanks and washing-tees 48 and 48A. The rinsed fiber 2 is then passed through section 50 wherein it is first air blasted in chamber 53 and then steam treated in section 55 to produce an oxide surface on the metal plate. The process is completed by passage of the metal plated fiber 2 through the drying unit 14 and reeling of the finished fibers on take-up reels 17 in the reeling section 16.
As seen generally in Figure 1, the apparatus is provided with means to convey the fibers 2 through the 132~328 ] ] (:)'J ~ J
system rapidly wlthout abradlng the flbers 2. The comblnatlon of strateglcally loc~ated gulde rollers 51, tenslon rollers 6, force iMposlng rollers ln the drylng section 14 and a synchronous drive assembly shown in FIGURE 16 rapidly conveys -the fibers 2 through the apparatus without abrasion of the fibers 2.
The operatlon begins wlth the pay-out assernbly 4 shown ln FIGURES 2 and 3. Functlonally, the flbers 2 from the pay-out assembly 4 are dellvered over a gulde roller 5 through the ten-slonlng rollers Ç to the pretreatment sectlon 8 shown in Figure 1.
As best seen in FIGURES 2 and 3, the pay-out assembly 4 ls comprlsed of a frame 52 on whlch the pay-out rollers 54 are mounted. The pay-out rollers 54 are mounted on the frame 52 on a rall 56 and a rail 58. The rollers 54 on rail 56 are arranged to pay-out the flbers 2 to the electroplatlng system whlle the rail 58 is an auxlliary rall adapted to mount the spare rollers 54 available to provlde alternate duty. A rail 60 mounts guide rollers 62 over whlch the fibers 2 from the pay-out rollers 54 travel to reach the tensionlng rollers 6.

- ].2 ~ 1 32 3 328 As best seen in Figure 2, the fibers 2 extend from the respective rol].ers 54 over individual guide roller 62 associated with a particular roller 54 to the common guide roller 5 and into the tensioning roller assembly 6. Guide bars 59 are provided to guide fibers 2 from the pay-out rollers 54 to the associated guide rollers 62.
As seen in Figure 3, the guide rollers 62 are aligned adjacent to each other to avoid interference between the fibers 2 as a plurality of fibers 2 are simultaneously delivered to the system to be treated and plated.
The pay-out assembly 4 delivers the fibers 2 over a guide roller 5 to a wetting roller 80 and then to the tensioning rollers 6. A wetting tub 84 is provided with water which wets the fibers 2 and enables suitable and more efficient cleaning and rinsing of the fibers 2 during pre-treatment. The tensioning rollers 6 seen in Figure 1 are shown in more detail in Figure 4.
The tensioning rollers 6 comprise an assembly of five rollers 90, all of which are driven through a single continuous chain 87 by a common source such as a variable speed motor 92.
Each roller 90 is mounted on a shaft 89 which also mounts a fixed gear 91 around which the chain 87 is arranged. Idler rollers 97 are also arranged to engage the chain 87. A gear 93 extending from 1~23328 the shaft of the variable speed motor 92 drlves the contlnuous chaln 87 through a chaln 101 and a gear 103 of Flgure 5 flxed to the shaft 8g of a roller 90. It ls necessary that tenslon be provlded to the fibers 2 at a locatlon in the llne upstream of the flrst platlng contact roller. The platlng contact roller and the flbers 2 must be ln tlght contact to facllitate the operation at the high voltage and high current levels necessary for the pro-cess. With tlght contact, low reslstance is provided between the flbers 2 and the contact rollers, thus the hlgh current passing through the system clrcult wlll not overload the flbers 2 causlng destructlon of the flbers. As a result, the tenslon roller assem-bly 6 is located upstream of the electroplatlng tanks 18, 20, 22, 24 ~FIGURE 1) to provlde that tenslon. On the other hand, the fibers should be sub~ected to as llttle drag as posslble. ~nher-ent ln the fibers 2 ls the tendency to separate at the surface and accumulate fuzz. The varlable drlve motor 92 ls coupled to all five of the rollers 90 to provide variable speed for the rollers at some speed equal to or less than the speed of the fibers 2. At carefully controlled speeds the necessary tenslon ls provided wlthout causing fuzz to accumulate on the fibers. The apparatus and process are designed to afford a tenslon roller assembly 6 ln ~ -~
~t 14 611(~ J
wllicll the tellsion rollers 90 travel at a slower speed than the ~ibers 2. The -tension on the flbers 2 ls maintained by varylny the speed of the tension roller 90 in response to visual determi-nation of the tension.
The pre-treated fibers 2 are next electroplated. As seen in Flgure 1, a plurality of electroplating tanks 18, 20, 22 and 24 are provided in series. Under the high voltage-high cur-rent conditions of the process, the series arrangement of electro-platlng tank 18, 20, 22 and 24 afford means for providing discrete voltage and current to the fibers 2 as a function of the accumula-tlon of metal-plating on the flbers 2. Thus, depending on the amount of metal-plating on the fibers 2, the plating voltage and current can be set to levels most sultable for the particular resistance developed by the flber and metal.
The electrolytic plating tank 18 of Figure 1 ls shown in Figures 5, 6 and 7 and is identical ln structure to the plating tanks 20, 22 and 24 shown ln Figure 1. The tank 18 is arranged to hold a bath of electrolyte. The tank 18 has mounted therewith contact rollers 100 and anode support bars 102 which are arranged in the circuit. The contact rollers 100 receive current from the bus bar 104 and the anode support bars 102 are connected directly to a bus bar 106. Each of the plating tanks 18, 20, 22 and 24 13233~8 are provided with slmllar but separate independent clrcuitry as seen ln FIGURE 15. The anode support bars 102 have mounted there-on anode baskets 110 arranged to hold and transfer current to nlckel or other ~etal-platlng chlps.
Each tank 18, 20, 22 and 24 ls also provided with heat exchangers 114 to heat the electrolyte bath to reach the desirable inltlal temperature at start-up and to cool the electrolyte durlng the high lntenslty current operatlon.
The tank 18 ls provlded wlth a well 103 deflned by a solld wall 105 ln whlch a level control 107 ls mounted and with a reclrculatlon llne 109. The reclrculatlon llne 109 lncludes a pump 111 and 2 fllter 113 and functlons to contlnuously reclrcu-late electrolyte from the well 103 to the tank 18. Under normal operatlng condltions reclrculated electrolyte wlll enter the tank 18 and cause the electrolyte in the tank to rlse to a level above the wall 105 and flow into the well 103. When electrolyte has evaporated from the tank the level ln the well wlll drop and call for make-up from the downstream rlnse sectlon 12 of Flgure 1.
The tank 18 ls also provlded wlth a llne 132 and pump 134 through whlch electrolyte ls pumped to a manlfold 128 that de-llvers the electrolyte to the spray nozzle 130 a~ove the contact rollers 100.

1323~28 lt` t,l 1()" /~
As ShOWIl in more detall in FIGURE lO, the ~ibers 2 pass over the contAt rollers 100 arld al-oulld idler rollers 112 located in proximity to the bottom of the tank. The idler roller~ 112 are provided in pairs around which the Elbers 2 pass to rnove lnto con-tact with the succeeding contact roller 100.
The rollers 100 in the tank 18 best shown in Flgure 15 communlcate wlth the bus bar 104 through contact member 118. The detail of the contact member 118 seen in FIGURE 8 shows that the contact members 118 are formed of a bar 120 and a plural array of ~ingers 122 and 124 that together provide the positlve contact over a sufficiently large area on the contact roller lO0 to avold creating a high resistance condition at the polnt of contact. The fingers 122 and 124 are resiliently mounted on the bar 120 and by the nature of the material, are urged lnto contact with the con-tact roller 100 at all times.
Thus, a high strength positive electrical contact assem-bly is provided ~or an environment wherein conventional brush con-tacts cannot serve well.
The hlgh voltage-high current process of the present in-vention is furtner facilitated by means for protecting the fibers2 durlng the passage between the electrolyte bath and the various contact rollers. The system includes the recirculating spray system 126 shown generally in FIGURES 5 and 6 through which 17 61109-72~6D
electrolyte ls recycled from the platlng tanks and sprayed through the spray nozzles 130 on the flbers 2 at contact polnts on the contact rollers 100.
The spray nozzles 130 are arranged with two parallel tu~ular arms 136 and 138 best shown in Flgure 9 havlng nozzle openlngs located on the lower surfaces thereof.
One tubular arm 136 of the spray nozzle 130, is arranged to dlrect electrolyte tangentlally on the flbers 2 at the polnt at whlch the fibers 2 leave the contact roller 100. The other tubu-lar arm 138 of the spray nozzle 130 ls arranged to dellver elec-trolyte directly on the top of the contact roller 100 at the polnt at whlch the flber 2 engages the contact roller 100. As prevlous-ly indlcated, lt ls vltal that sufflclent tenslon be applled on the flbers 2 to insure that the flbers 2 are malntalned ln a tlght direct llne between the contact rollers 100 and the ldler rollers 112. The need for a tight llne is to assure that the low contact resistance suitable for current travel is avallable wlth hlgh conductlvity through the flbers 2 from the contact rollers 100 to the electrolyte bath. The electrolyte which ls reclrculated over the contact rollers 100 and the flbers 2 provlde a parallel re-slstor ln the clrcult and serve to cool the flbers 2.
It ls known that the rlbers 2 belng plated have a low fusing current, such as 10 amps for a 12K tow of about 7 microns in diameter. However, the process requires about 25 amps between contacts or about 125 amps per strand in each tank.
Furthermore, both contact resistance and anisotropic resistance must be overcome. The contact resistance of 12K tow of about 7 microns on pure clean copper is about 2 ohms, thus at 45 volts twenty-two and one-half amps are required before any plating can occur. The anisotropic resistance is 1,000 times the long axis. Thus, the total contact area must be 1,000 times the tow diameter, which for 7 microns is 0.34 inches. Practice has taught that one-half inch of contact will properly serve the electrical requirement of the system when plating 7 micron tow, hence two inch contact rollers 100 are used. It is also vital that the contact rollers 100 be located at a specified distance above the electrolyte bath to enable the system to operate at the high voltages necessary to achieve the plating of the process. In practice, it has been found that the contact rollers 100 should be located two inches from the electrolyte bath when voltages of 16 to 25 volts are applied. Further, it has been found that recirculation of about 2 gal~ons per minute per contact roller traveling at about 1~ to 25 ft./min. will properly cool the fiber o and~provide a suitable parallel resistor when above 5,000 amps are passed through the system.

The electrolyte in the process is a solution constituted of eight to ten ounces of metal, preferably in the form of ~iC12 and NiSO4 per gallon of solution.
The pH of the solution is set at 4 to 4.5 and the temperature maintained between 145 and 150 F. Recir-culation of the electrolyte through the spray nozzles 130 at the desired rate requires that the nozzle openings be 3/32 inches in diame~er on 1/8" centers over the length of each tubular arm 136 and 138. The presence of e~ectrolyte on the fibers is vital, but care is taken to avoid excessive electrolyte otherwise the contact rollers will 20 become su~jected to the plating occurring in the electrolyte.

The contact r~lIers 1~0 are shown in detail in FIGURES 12-14. Each contact roller 100 is located in close proximity to the electrolyte in the plating tanks and each is adapted to transmit high current through the system in a high intensity voltage environment. The 30 contact roller 100 thus is designed for continual replace-ment. The contact roller 100 is provided with fixed end )~ f,ll(J'-~ /"~Jr,~, mounting sections 170 and 172 which hold a cylindrical copper tl~be 17g. The cyl~lldr1cal copper tube 174 ls arranged to contact the comMutator fingers 122-124 best shown in Figure 8 and deliver cur-rent through both the flbers 2 and recycled electrolyte to the electrolyte bath. The copper tube 174 is formed of conventional type L copper which must be able to carry 350 amperes. The dia-meter of the tubing is critical in that the diameter dictates the contact surface for the fibers 2 and the distance that the contact roller 100 will be from the electrolyte surface. As a result, the mounts 170 and 172 are fi~edly arranged in alignment with each other to releasably support the tube 174 of the contact roller 100. The mount 170 is provlded with a bearing support 176 through which a screw mount 178 passes. The screw mount 178 rotatably supports the copper tube 174 on a bushing support 180 and has the capacity to release the copper tube 174 upon retractlon of the bushing support 180 by withdrawing the screw 178. The mount 172 lncludes a bushing support 182 on whlch a detent 184 is formed.
Each copper tube 174 is provided with a notched mating slot 186 to .it around the detent 184 and effect positive attachment of the copper tube 174 to the bush1ng support 182 thereby obviating any uncertalnty in alignment and facilitating dispatch ln replacing each copper tube section 174.

~, ~l t,llO'~
The overall electrical system 188 of the process an~
apparatus ls shown schematically in Flgure 15 whereln t~,e capacity for discrete appllcation of voltage and current to each electro-lytlc tank 18, 20, 22, 24 can be seen. Conventlonal rectiflers 189, 191, 193 and 195 are arranged as a D.C. power source to de-llver current to the respective contact rollers 100 on each electrolytic tank. Bus bars 104, 194, 196, 198 are shown for lllustratlon extending respectlvely from the rectlflers 189, 191, 193 and 195 to one of the six contact rollers 100 on the electro-lytlc tanks 18, 20, 22 and 24. However, all slx contact rollers 100 on each electrolytlc tank are dlrectly connected to the same bus bar. Bus bars 106, 202, 204 and 206 are shown extending re-spectlvely from the same rectlfiers 189, 191, 193, and 195 through cables 208 to one anode support bar 102 best shown ln Figure 5 mounted on the electrolytic tanks 18, 20, 22 and 24. Again the respectlve anode bus bars contact each anode support bar 102 mounted on each electrolytlc tank connected to the bus bar.
As a result of the arrangement, dlscrete hlgh voltage can be dellvered to each electrolytic tank 18, 20, 22, 24 as a functlon of the metal platlng on the flbers 2 ln each electrolytlc tank.
Practice has taught that the voltage in the flrst elec-trclyte tank 18 should not be below 16 volts and seldom be below 24 volts. The voltage ln the second tank 20 should not be below 14 volts and the voltage in the third electrolyte tank 22 should not be below 12 volts.

- 22 _ 1 3 2 3 32~

Illustratively, fibers 2 have been coated in a system of three rectifier-electrolyte tank assemblies, rather than the four shown in Figures 1 and 15 under the following conditions wherein excellent coating has resulted:

AMPS 1,400 1,400 1,400 The nickel metal coated fibers 2 produced under these conditions have the following properties and characteristics:
Filament Shape Round (but dependent on graphite fiber) Diameter 8 microns Metal Coating Approximately 0.5 microns thick, about 50% of the total fiber weight.
Density 2.50 - 3.00 grams/cm.3 Tensile Strength Up to 45Q,000 psi Tensile Modulus 34 M psi Electrical 0.008 ohms/cm. (12K tow) Conductivity 0.10 ohms/1000 strands/cm.
After the nickel plating has occurred, the fully plated fibers 2 are delivered to the rinsing section 12 seen in Figure 1.

132~328 The drag-out section 42 and rlnse sectlon 46 are arrang-ed with tanks to accumulate the dlscharge from the tees 44, 44A, 44B, 48 and 48A and both neutralize the dlscharge for waste dls-posal and provlde a reposltory for accumulatlon of make-up for the electrolyte tanks 18, 20, 22 and 24.
The apparatus ls arranged for synchronous operatlon as shown ln Flgures 16 - 18. A motor 222 ls provlded to lnsure that the contact rollers 100 best shown ln Flgures 5 and 9 and the gulde rollers 51 rotate at the same speed to avoid abradlng the fibers 2.
The motor 222 dlrectly drives an assembly of rollers 223 - arranged to effect a capstan. The rollers 223 are located ln thedryer 14 and as best seen ln Flgure 17 cause the flber to reverse dlrectlon slx tlmes. The reversal ln dlrectlon ls sufflclent to impose a force on the fibers 2 that will pull the fibers through the apparatus without allowlng slack.
In addltion, the motor 222 ls connected by a gear and chaln assembly to clrive each contact roller 100 and each guide roller 51 at the same speed.
In essence, the gear and chain assembly is comprlsed of guide drlve assemblles 225, best seen in Figure 1~ and contact roller drive assemblles 227. Each -24 ~

guide drive assembly 225 includes drive transmission gear 230 mounted on shafts 231, a gear 224 fixedly secur-ed to the guide roller 51 and a chain 233 that engages the gears 230 and 224.

The contact roller drive assembly includes drive transmission gear 239 mounted on the shafts 231 common to the gears 230, a gear 241 fixedly secured to each contact roller 100 and a chain 243 that engages both gears 239 and each of the gears 241 on the six contact rollers 100 associated with each electrolyte tank.
The location of the capstan rollers 223, seen in FIGURE 18, in the dryer 14 enhances drying. The flat surface and force applied to the fibers 2 spreads the fibers and thereby accelerates drying.

The system also includes a variable speed clutch override drive motor 219 for the take-up reels 17.
The force generated by the variable torque motor 219 pro-vides the force to draw the fiber 2 through the system.
However, the capstan rollers 223 provide a means to isolate the direct force imposed on the fibers 2 at the take-up reels 17 from the fibers 2 upstream of the capstan rollers.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A contact roller comprising:
(a) a removably mounted copper tube;
(b) a first fixed bearing;
(c) a bushing mounted on the first fixed bearing having an outside diameter equal to the inside diameter of the copper tube;
(d) a second fixed bearing mounted in alignment with the first fixed bearing;
(e) a bushing mounted on the second fixed bearing, said bushing having the same outside diameter as the bushing mounted on the first fixed bearing; and (f) means for translating the bushing mounted on the first fixed bearing horizontally to release the copper tube.

2. An apparatus as in claim 1 further comprising a detent extending from the second bearing bushing; a notch in the remov-ably mounted copper tube adapted to align with and pass over the detent in the second bearing bushing.

3. An apparatus as in claim 1 wherein the means for trans-lating the first bushing mounted on the first fixed bearing to release the copper tube is a horizontally disposed screw aligned with the central axis of the copper tube.