EP0194577B1 - Process and apparatus for electroplating strips - Google Patents

Process and apparatus for electroplating strips Download PDF

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Publication number
EP0194577B1
EP0194577B1 EP86102928A EP86102928A EP0194577B1 EP 0194577 B1 EP0194577 B1 EP 0194577B1 EP 86102928 A EP86102928 A EP 86102928A EP 86102928 A EP86102928 A EP 86102928A EP 0194577 B1 EP0194577 B1 EP 0194577B1
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EP
European Patent Office
Prior art keywords
strip
anode
strips
electrolyte
accordance
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EP86102928A
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German (de)
French (fr)
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EP0194577A3 (en
EP0194577A2 (en
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Kurt Held
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Individual
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Priority to AT86102928T priority Critical patent/ATE49242T1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B44—DECORATIVE ARTS
    • B44B—MACHINES, APPARATUS OR TOOLS FOR ARTISTIC WORK, e.g. FOR SCULPTURING, GUILLOCHING, CARVING, BRANDING, INLAYING
    • B44B5/00—Machines or apparatus for embossing decorations or marks, e.g. embossing coins
    • B44B5/02—Dies; Accessories
    • B44B5/026—Dies
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D7/00—Electroplating characterised by the article coated
    • C25D7/06—Wires; Strips; Foils
    • C25D7/0614—Strips or foils

Definitions

  • the invention relates to methods for the galvanic coating of a metallic, endless belt with a metal layer, in particular for use as a press belt in a double belt press, according to the preambles of claims 1 to 4 and devices for carrying out these methods according to the preambles of claims 7 to 10.
  • Such belts which are mainly used as press belts in double belt presses, are used to exert surface pressure on sheet-like materials, such as decorative laminate laminates, chipboard, fiberboard, electrolaminate and the like.
  • the material to be pressed is guided between two endlessly rotating press belts which are subjected to pressure and, if necessary, heat and hardened in the process (see DE-OS 2421296).
  • Such press belts are usually made of high tensile steel.
  • the surfaces of the press belt are galvanized with a hard, metallic and wear-resistant layer. If the surface of the material to be pressed is to be provided with a structure, embossing tapes are used, which, like the press belts, consist of a steel strip, with a soft, metallic layer being galvanized onto the surface, into which the desired structure is introduced, and then for protection a further hard layer is electroplated onto this soft layer (see DE-PS 29 50 795).
  • Trough-shaped baths which are filled with a liquid electrolyte which dissociates into ions which contain the desired metal atoms to be deposited are used for electroplating metal coatings on a metallic object.
  • An anode made of a highly conductive material is immersed in these electrolytes.
  • the object to be coated is completely immersed in the bath and switched as a cathode. If a DC voltage source is attached outside the bath between the cathode and the anode, a current consisting of the ions of the electrolyte flows in the bath between the cathode and the anode and at the cathode the metal ions are reduced to metal atoms by electron absorption, which then form a metallic coating on the cathode separate.
  • the baths available in the electroplating plants have certain maximum lengths and depths.
  • endless strips which geometrically form a closed circular ring, entirely in such an electroplating bath, it is known to fold these strips and only then to introduce them into the electroplating bath. With this method, however, only strips of around 6 m in length can be coated, which corresponds to a ring diameter of around 2 m in the largest available baths.
  • US-A-3 772 163 describes an inflatable plastic bag arranged in a container, on the surface of which there are copper mesh electrodes.
  • FR-A-2 285 178 shows chambers filled with an electrolyte which are rotatably arranged on the inside of a container wall by means of a shaft.
  • US-A-3 783 110 shows a rotatable cylindrical container with anodes arranged parallel to the wall of the container.
  • the invention has for its object to enable the electroplating of metallic layers on endless strips of any size, while the quality of the deposited metal layers is to be improved.
  • the double belt press 1 shown in FIG. 1 has four deflection drums 2, 3, 4, 5 mounted in a press frame.
  • the press frame is omitted in the drawing for the sake of clarity.
  • a press belt 6, 7, which is tensioned with hydraulic cylinders 8, is guided around two of the deflecting drums, which rotate according to the arrows in the deflecting drums 2 and 3.
  • a material web 9 leading from right to left in the drawing which can consist of laminates impregnated with synthetic resin, fiber-binder mixtures or the like, is compressed with simultaneous application of heat and pressure.
  • the pressure exerted on the material web 9 is applied hydraulically or mechanically to the inner sides of the press belts 6, 7 via pressure plates 10, 11 and transmitted from there to the material web.
  • a fluid pressure medium which can be pressurized, for example oil or air, is introduced into the space 12, which is delimited at the top and bottom by the pressure plate 10 or the inside of the press belt 6 and on the sides by the seal 13.
  • 7 fixed rollers 14 are attached between the pressure plate 11 and the inside of the press belt. With the help of hydraulic cylinders 60, the pressure plate 11 and thus the rollers 14 are set against the inside of the press belt 7.
  • the press belt 6 or 7 is an endless belt made of a high-tensile steel grade, which in the relaxed state has an annular shape.
  • the surface of the press belt must have a high hardness.
  • the required hardness is usually achieved by galvanic hard chrome plating of the surface with layer thicknesses of 30 to 100 micrometers.
  • the device shows a device according to the invention for the galvanic application of a hard chrome layer to the inside of the endless press belt 15.
  • the device consists of a rectangular base plate 16 made of steel, the area of which is dimensioned such that it can hold the largest press belt to be chromed.
  • the press belt 15 is placed upright on this base plate 16 in the untensioned state, with which it forms a circular ring, in an annular seal 17 resting on the base plate.
  • another press belt 15a is also placed on an annular seal 17, which is hidden in the drawing.
  • This press belt 15a has a smaller diameter than the outer press belt 15 and is arranged concentrically with the press belt 15.
  • the two press belts 15 and 15a have the same width or, in the upright state, the same height, so that an annular cavity 21 is formed between the inner surface 18 of the outer press belt 15 and the outer surface 19 of the inner press belt 15a.
  • the electrolyte usually chromic acid, is in this cavity.
  • the two bands 15 and 15a are clamped firmly on the base plate 16 by means of clamping elements 20 or counter-clamping elements 54, so that their annular arrangement and their relative position to one another are fixed during the chromium plating process.
  • the clamping elements 20 are attached so that they are outside the cavity 21.
  • the inner band 15a is tensioned from the inside with counter-tensioning elements 54 into a circular shape.
  • An insulating plate 23 made of plastic means that there is no electrically conductive connection between the mast 22 and the base plate 16.
  • a rotatably mounted outer sleeve 24 is attached to this mast.
  • This outer sleeve 24 carries two arms 25 made of copper, forming an angle of 180 degrees, the length of which is greater than the radius of the inner band 15a and smaller than the radius of the outer band 15.
  • the arms 25 are mounted at a height such that they protrude beyond the two press belts 15 and 15a.
  • a plurality of pencils 26 are attached, which extend into the cavity 21 almost to the base plate 16.
  • the pencils 26 Due to the appropriately selected length of the arms 25, the pencils 26 have a certain distance both from the inner surface 18 of the press belt 15 and from the outer surface 19 of the press belt 15a and therefore do not touch these surfaces even when the outer sleeve 24 and thus the arms 25 are rotated.
  • These cuffs are held in their position by the tensioning elements 20.
  • the clamping elements 20 are electrically insulated from the base plate 16. Since the band 15 rests on an annular seal 17 made of rubber or plastic, it likewise has no electrical contact with the base plate 16.
  • FIG. 3 The structure of such an annular seal 17 corresponding to a section at point A in FIG. 2 is shown in FIG. 3.
  • This seal consists of an annular body 42 which rests on the base plate 16.
  • the body 42 is made of an electrically non-conductive material such as rubber or plastic.
  • On the top of the body 42 there is an annular groove 43 in which a holder 44 is firmly inserted.
  • This holder 44 in turn consists of two parts, namely two annular iron rails 45 and 46.
  • One of the iron rails 45 has a shoulder 48 in its upper part and a groove 49 adjoining it.
  • the press belt 15 is now placed in the holder 44 in such a way that it stands on the shoulder 48 of the iron rail 45 and rests with the lower part of one surface on the wall 50 of the second iron rail 46.
  • the contact pressure can be increased further by allowing a pressurized liquid, for example water or the electrolyte liquid itself, to act in the groove 49 on the O-ring 51. This ensures that the press belt 15 is both firm and against the one in the cavity 21 located electrolyte sealingly rests on the base plate 16, and is also electrically insulated from the base plate
  • the sleeves 27 are connected via flexible lines 52 to a ring line 64 consisting of copper rods with a sufficiently large line cross section, which in turn is connected to the negative pole of a DC voltage source.
  • the pencils 26 are connected to the positive pole of the DC voltage source via the arms 25 and the mast 22, which in turn is contacted through the base plate 16.
  • the outer band 15 is thus connected as the cathode and the pencils 26 as the anode.
  • the outer sleeve 24 of the mast 22 is driven by means of a motor 28 and a chain 53 for transmitting power to a gear 55 fastened to the outer sleeve 24, so that the pencils 26 acting as anode rotate at a uniform speed.
  • chromium atoms are now deposited from the electrolyte in the cavity 21 on the part of the inner surface 18 of the press belt 15 which acts as the cathode and is opposite the anode 26. Since the anode 26 rotates, a chrome layer with a certain thickness is deposited on the entire inner surface 18 per revolution. The desired total layer thickness of the hard chrome layer is obtained by appropriate selection of the number of revolutions of the anode 26.
  • An increase in the deposited layer thickness per revolution is possible by increasing the number of adjacent pencils 26 which form the anode. In the case of a large number of pencils lying next to one another, care must be taken that they are attached in such a way that they have the shape of a circular section when viewed in cross-section, so that it is ensured that they do not collide with a surface 18, 19 of the strips when the outer sleeve 24 rotates.
  • Another measure for increasing the deposited layer thickness consists in attaching more than two arms 25 with the anodes attached to them on the outer sleeve 24. With these measures, it should be noted that the current strength increases accordingly and the power of the DC voltage source must be designed for this. Of course, with low power of the DC voltage source, only one arm 25 with an anode can be attached to the outer sleeve 24, in which case the number of cycles for a certain total layer thickness increases.
  • the dimensioning of the DC voltage source which is usually represented by a mains transformer with a subsequent rectifier, is carried out according to the known laws of electrolysis.
  • the properties of the deposited chrome layer are sensitive to the temperature of the electrolyte and the current density.
  • the temperature of the electrolyte in the cavity 21 is therefore constantly checked by means of temperature sensors mounted in the cavity and kept constant by supplying heated electrolytes.
  • Fresh electrolyte is supplied from below through the base plate 16 into the cavity 21.
  • the used electrolyte is replaced because the concentration of the chromium ions on the strip surface decreases accordingly. So both the temperature as well Concentration of the electrolyte constant over the entire electroplating period.
  • the current density is also automatically kept constant at all points, so that overall a very uniform layer thickness of the hard chrome layer is obtained on the entire strip surface. It has also been shown that hydrogen embrittlement hardly occurs, thus eliminating the risk of the surface layer cracking under tensile stress.
  • the flexural fatigue strength of the strips chrome-plated by the method according to the invention is also far higher than that of conventionally chrome-plated strips.
  • the current yields in hard chrome plating are approximately 20%, i.e. H.
  • Around 80% of the electricity required is used for the electrolysis of water.
  • This produces gaseous hydrogen at the cathode, which escapes from the cavity 21.
  • the rising gas bubbles entrain part of the electrolyte, with which the hydrogen gas is mixed with chromic acid vapor.
  • a time consisting of plastic film can be stretched over the entire belt arrangement, as indicated schematically in FIG. 5 by the reference numeral 30, in which these vapors are collected and extracted.
  • the supply lines of the current to the anode and cathode must be made with the lowest possible resistance. Therefore, as is common in electroplating, lines made of solid copper with a correspondingly large cross section are used. Since the anode 26 moves during the galvanization, the supply of the current in the mast 22 has a special configuration, which can be seen in cross section in FIG. 4.
  • the mast 22 consists of a hollow square tube 56 which is screwed onto the base plate 16 in an electrically insulated manner by means of a base flange 31 and a plastic plate 23.
  • a copper rod 32 runs in the square tube and is in contact with the power supply from the DC voltage source via an opening in the base plate 16.
  • This copper rod 32 terminates at its upper end with a flange 33 on which an outer ring flange 34 and an inner ring flange 35 are mounted in such a way that an annular cavity remains free between the two.
  • the outer sleeve 24 has in its lower part an annular counter flange 39 and a shaft 36 running in the middle.
  • This shaft 36 extends into the cavity 57 formed by the inner ring flange 35 and is rotatably fastened there on the inner ring flange 35 by means of two ball bearings 38, so that this shaft and with it the entire outer sleeve 24 can rotate about the fixed copper rod 32.
  • the ball bearings 38 are insulated from the inner ring flange 35 by means of an insulation 37 made of plastic. The distance between the two ball bearings 38 is fixed by an upper spacer sleeve 58, while the lower ball bearing rests on an insulating plate 40 via a lower spacer sleeve 59, which in turn lies on the flange 33.
  • the annular counter flange 39 of the outer sleeve 24 extends into the cavity formed by the inner ring flange 34 and outer ring flange 35 in such a way that a slight play of a few 1/10 mm remains between the walls.
  • This space determined by the game is filled with mercury 61, which conducts electricity well, and ensures the current transmission from the flange 33 via the fixed ring flanges 34 and 35 to the rotatable counter flange 39 of the outer sleeve 24 and from there via the arms 25, which are at the top Part of the outer sleeve 24 are mounted on the anode 26th
  • a gear 55 is mounted on the outer sleeve 24, which is driven by the motor 28 via the chain 53 and causes the outer sleeve to rotate.
  • the motor 28 is in turn attached to the square tube 56 so that no current flows from the outer sleeve 24 via the chain 53 to the motor 28 and the square tube 56, the gearwheel is electrically insulated from the outer sleeve by means of insulating foils 41.
  • This construction also ensures that no current flows from the inner ring flange 35 via the ball bearings 38 to the shaft 36, since the large currents required for the chrome plating could otherwise cause dangerous overheating on the small cross sections of the ball bearings.
  • the shaft 36 itself is at a short distance from the insulation plate 40 and thus from the flange 33.
  • the belts are arranged on the device in such a way that the belt with the smaller diameter is switched as the cathode. 2, this is the press belt 15a with the surface 19 to be chrome-plated.
  • the connection of the cathode to the negative pole of the voltage source now takes place via leads to the inside of the press belt 15a, as described above, while the anode continues with the pencils 26 connected is. Otherwise the arrangement remains unchanged.
  • the chromium atoms from the electrolyte located in the cavity 21 then separate with the voltage source switched on and the arms 25 rotating on the outer surface 19 of the press belt 15a and form the desired chromium layer.
  • the device according to the invention it is also advantageously possible to chrome-plate two press belts at the same time, the inside of the belt lying on the outside and the outside of the belt lying on the inside being chrome-plated.
  • cuffs are attached to the inside of the inside band 15a corresponding to the cuffs 27 of the outside band.
  • the cuffs 27 are both on the outer band 15 and the inner band 15a with tensioning elements 20 held, which, as shown in Fig. 5, consist of copper rods and serve in this embodiment at the same time the power supply.
  • the device shown in FIG. 5 is constructed in the same way as that in FIG. 2, except that here the power transmission from the motor 28 to the outer sleeve 24 takes place via a gear 29 with a suitably selected reduction ratio.
  • the parts identical to FIG. 2 are designated in FIG. 5 with the same reference numerals.
  • Both the sleeves of the outside band 15 and those of the inside band are connected to the negative pole of the voltage source, so that both bands now form the cathode at the same time. If the arms 25 rotate with the pencils 26 acting as an anode, chromium atoms are deposited both on the inner surface 18 of the outer band 15 and on the outer surface 19 of the inner band 15a. This means that one surface of each band is covered with a chrome layer. When dimensioning the voltage source, the higher current requirement must of course be taken into account.
  • a further development of the method enables the simultaneous chrome plating of the inside and outside surface of a single press belt 15b.
  • three press belts 15, 15b and 15a with decreasing diameters are placed concentrically one inside the other on the base plate 16.
  • Fig. 6 shows a section in the direction of the diameter to the common center through the walls of the three interlocking press belts.
  • These three press belts stand on seals 17, 17b and 17a, the seals 17 and 17a being constructed in accordance with the seal shown in FIG. 3, so that additional tensioning elements for the press belts can be dispensed with.
  • the inner 15a and outer press belt 15 can, however, also be tensioned with the usual tensioning elements 20 or 54, which makes the use of this seal for these two press belts 15, 15a unnecessary.
  • the middle press belt 15b is, however, clamped in such a seal, so that the inner and outer surfaces thereof are not covered for simultaneous chrome plating, and on the other hand the press belt 15b is fixed on the base plate 16.
  • the seal 17b additionally has a peg ring 47 which runs in both iron rails 45, 46 and which is made of a highly conductive material such as copper. This pin ring 47 is connected at several points from below through openings 65 in the base plate 16 through contact plug 63 to the negative pole of the voltage source, so that the band 15b is connected as a cathode.
  • the method and the corresponding device for carrying out the electroplating of a metal layer is described here using the example of hard chrome plating of a press belt.
  • both the method and the device for electroplating any other metal layer onto the press belt can be used, for example for coppering or nickel plating.
  • the conditions known for electroplating for the respective metal must be observed.
  • the anode 26 must then consist of a special material, for example of copper rods, if a copper layer is to be galvanically applied to the press belt. If it appears expedient, instead of the anode 26 consisting of individual rods, a single contiguous surface can also be selected for the anode.
  • the type of electrolyte should be chosen as is familiar to the person skilled in the art.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electroplating Methods And Accessories (AREA)

Abstract

For the electrodeposition of a metal coating onto a surface of an endless belt, such as a press belt for use in a double band press, an annular bath is formed by a pair of endless belts. The belts have different diameters and are arranged concentrically about a center point on a horizontal base plate. The belts extend vertically upwardly from the base plate so that one belt forms the radially inner surface of the bath and the other forms the radially outer surface, an aqueous electrolytic solution is filled into the annular bath. An anode is supported in the bath and one of the endless belts forms a cathode. The anode and cathode are connected to a constant voltage sourse and a metal coating can be deposited on the belt acting as the cathode. A mast extends vertically upwardly from the center point and is supported on the base plate. Horizontal arms extend outwardly in opposite directions from the mast and support the anode. The mast rotates about its vertical axis with the anode moving through the annular bath.

Description

Die Erfindung betrifft Verfahren zur galvanischen Beschichtung eines metallischen, endlosen Bandes mit einer Metallschicht, insbesondere zur Verwendung als Pressband in einer Doppelbandpresse, gemäß den Oberbegriffen der Patentansprüche 1 bis 4 und Vorrichtungen zur Durchführung dieser Verfahren gemäß den Oberbegriffen der Patentansprüche 7 bis 10.The invention relates to methods for the galvanic coating of a metallic, endless belt with a metal layer, in particular for use as a press belt in a double belt press, according to the preambles of claims 1 to 4 and devices for carrying out these methods according to the preambles of claims 7 to 10.

Solche Bänder, die hauptsächlich als Pressbänder in Doppelbandpressen eingesetzt werden, dienen zur Ausübung von Flächendruck auf bahnförmige Werkstoffe, wie dekorative Schichtstofflaminate, Spannplatten, Faserplatten, Elektrolaminate und dergleichen. Dazu wird das Pressgut zwischen zwei endlos umlaufenden Pressbändem, die mit Druck und falls nötig mit Wärme beaufschlagt werden, geführt und dabei ausgehärtet (siehe DE-OS 2421296). Üblicherweise werden solche Pressbänder aus hochzugfestem Stahl hergestellt.Such belts, which are mainly used as press belts in double belt presses, are used to exert surface pressure on sheet-like materials, such as decorative laminate laminates, chipboard, fiberboard, electrolaminate and the like. For this purpose, the material to be pressed is guided between two endlessly rotating press belts which are subjected to pressure and, if necessary, heat and hardened in the process (see DE-OS 2421296). Such press belts are usually made of high tensile steel.

Damit die Pressbänder bei dem zum Verpressen angewendeten Druck nicht zu schnell verschleissen, erhalten die Oberflächen des Pressbandes eine harte, metallische und verschleißfeste Schicht aufgalvanisiert. Soll die Oberfläche des Pressgutes mit einer Struktur versehen werden, so verwendet man Prägebänder, die ebenso wie die Pressbänder aus einem Stahlband bestehen, wobei auf dessen Oberfläche eine weiche, metallische Schicht aufgalvanisiert wird, in die die gewünschte Struktur eingebracht wird, Anschließend wird zum Schutz auf diese weiche Schicht eine weitere, harte Schicht aufgalvanisiert (siehe DE-PS 29 50 795).So that the press belts do not wear out too quickly under the pressure used for pressing, the surfaces of the press belt are galvanized with a hard, metallic and wear-resistant layer. If the surface of the material to be pressed is to be provided with a structure, embossing tapes are used, which, like the press belts, consist of a steel strip, with a soft, metallic layer being galvanized onto the surface, into which the desired structure is introduced, and then for protection a further hard layer is electroplated onto this soft layer (see DE-PS 29 50 795).

Zum Aufgalvanisieren von Metallüberzügen auf einem metallischen Gegenstand werden wannenförmige Bäder verwendet, die mit einem flüssigen Elektrolyten gefüllt sind, der in Ionen dissoziiert, die die gewünschten, abzuscheidenden Metallatome enthalten. In diesen Elektrolyten taucht eine aus einem gut leitfähigen Material bestehende Anode ein. Der zu beschichtende Gegenstand wird ganz in das Bad getaucht und als Kathode geschaltet. Wird außerhalb des Bades zwischen Kathode und Anode eine Gleichspannungsquelle angebracht, so fließt im Bad zwischen Kathode und Anode ein aus den Ionen des Elektrolyten bestehender Strom und an der Kathode werden die Metallionen durch Elektronenaufnahme zu Metallatomen reduziert, die sich auf der Kathode dann als metallischer Überzug abscheiden.Trough-shaped baths which are filled with a liquid electrolyte which dissociates into ions which contain the desired metal atoms to be deposited are used for electroplating metal coatings on a metallic object. An anode made of a highly conductive material is immersed in these electrolytes. The object to be coated is completely immersed in the bath and switched as a cathode. If a DC voltage source is attached outside the bath between the cathode and the anode, a current consisting of the ions of the electrolyte flows in the bath between the cathode and the anode and at the cathode the metal ions are reduced to metal atoms by electron absorption, which then form a metallic coating on the cathode separate.

Die in den Galvanisieranstalten verfügbaren Bäder besitzen gewisse maximale Längen und auch Tiefen. Um endlose Bänder, die geometrisch gesehen einen geschlossenen kreisförmigen Ring bilden, ganz in einem solchen Galvanisierbad unterbringen zu können, ist es bekannt, diese Bänder zu falten und dann erst in das Galvanisierbad einzubringen. Mit dieser Methode sind jedoch nur Bänder von rund 6 m Länge, das entspricht einem Ringdurchmesser von rund 2 m in den größten verfügbaren Bädern zu beschichten.The baths available in the electroplating plants have certain maximum lengths and depths. In order to be able to accommodate endless strips, which geometrically form a closed circular ring, entirely in such an electroplating bath, it is known to fold these strips and only then to introduce them into the electroplating bath. With this method, however, only strips of around 6 m in length can be coated, which corresponds to a ring diameter of around 2 m in the largest available baths.

Für verschiedene Anwendungen, wie zum Beispiel der kontinuierlichen Spanplattenherstellung, ist es jedoch nötig, lange Pressen zu bauen, die Längen von rund 12 m oder mehr besitzen können, so daß das Pressband eine Umfangslänge von wenigstens 26 m erreicht, Solche langen Pressbänder können jedoch nicht mehr herkömmlich auf galvanischem Wege beschichtet werden.For various applications, such as continuous particle board production, however, it is necessary to build long presses which can have lengths of around 12 m or more, so that the press belt reaches a circumferential length of at least 26 m, but such long press belts cannot more traditionally coated by electroplating.

Ein weiterer Nachteil der in einem herkömmlichen Bad vorgenommenen Galvanisierung wird durch die Faltung der Pressbänder hervorgerufen. Durch diese Faltung erhält man verschieden weite Abstände zur Anode und die Stromdichte zwischen Anode und Kathode im Bad variiert beträchtlich, so daß eine unterschiedliche Dicke der abgeschiedenen Metallschicht auf der Bandoberfläche resultiert. Das kann wiederum zu Dickenschwankungen im hergestellten Pressgut führen und am Pressgut eine aufwendige Nacharbeit wie Schleifen erfordern. Außerdem hat sich gezeigt, daß bei Pressbändem, die in herkömmlichen Bädern galvanisch beschichtet werden, eine verstärkte Wasserstoffversprödung eintritt. Diese Wasserstoffversprödung führt zu Rissen und Brüchen in der abgeschiedenen Metallschicht und kann damit das gesamte Pressband unbrauchbar machen.Another disadvantage of the galvanization carried out in a conventional bath is caused by the folding of the press belts. This folding gives different distances to the anode and the current density between the anode and cathode in the bath varies considerably, so that a different thickness of the deposited metal layer on the strip surface results. This, in turn, can lead to fluctuations in the thickness of the pressed material and can require extensive reworking such as grinding. It has also been shown that press tapes that are galvanically coated in conventional baths are subject to increased hydrogen embrittlement. This hydrogen embrittlement leads to cracks and breaks in the deposited metal layer and can therefore render the entire press belt unusable.

Zur galvanischen Beschichtung von Behälterwänden sind in der Literatur spezielle Galvanisierverfahren und -vorrichtungen bekannt geworden. So beschreibt die US-A-3 772 163 einen in einem Behälter angeordneten, aufblasbaren Kunststoffsack, auf dessen Oberfläche sich Kupfemetzelektroden befinden. Die FR-A-2 285 178 zeigt mit einem Elektrolyten gefüllte Kammern, die mittels einer Welle drehbar an der Innenseite einer Behälterwand angeordnet sind. In der US-A-3 783 110 ist ein rotierbarer zylindrischer Behälter gezeigt mit parallel zur Wand des Behälters angeordneten Anoden. Keine dieser Druckschriften befaßt sich jedoch mit der galvanischen Beschichtung von endlosen Bändern.For the galvanic coating of container walls, special electroplating processes and devices have become known in the literature. Thus, US-A-3 772 163 describes an inflatable plastic bag arranged in a container, on the surface of which there are copper mesh electrodes. FR-A-2 285 178 shows chambers filled with an electrolyte which are rotatably arranged on the inside of a container wall by means of a shaft. US-A-3 783 110 shows a rotatable cylindrical container with anodes arranged parallel to the wall of the container. However, none of these documents deals with the galvanic coating of endless strips.

Der Erfindung liegt die Aufgabe zugrunde, das Aufgalvanisieren von metallischen Schichten auf endlosen Bändern beliebiger Umfangsgröße zu ermöglichen, wobei gleichzeitig die Qualität der abgeschiedenen Metallschichten verbessert werden soll.The invention has for its object to enable the electroplating of metallic layers on endless strips of any size, while the quality of the deposited metal layers is to be improved.

Die Lösung dieser Aufgabe wird durch die in den Patentansprüchen 1 bis 4 beschriebenen Lehren vermittelt und zur Durchführung dieser Verfahren dienende Vorrichtungen werden in den Patentansprüchen 7 bis 10 angegeben.The solution to this problem is imparted by the teachings described in claims 1 to 4 and devices used to carry out these methods are specified in claims 7 to 10.

Die mit der Erfindung erzielbaren Vorteile bestehen insbesondere darin, daß das galvanische Beschichten von endlosen Bändern beliebiger Umfangslänge ermöglicht wird und die Beschränkung auf die durch das Bad vorgegebenen maximalen Größen damit entfällt. Damit geht einher, daß der Bedarf an Elektrolyten stark vermindert wird und die benötigte Stromstärke zu Lasten der Verchromungszeit verringert werden kann. Soll nur eine Oberfläche des endlosen Bandes beschichtet werden, so ist keine Abdekkung der Rückseite des Bandes wie bei den herkömmlichen Verfahren mehr nötig. Weiter hat sich gezeigt, daß sowohl die Abscheidung einer gleichmäßigen, dicken Schicht gelingt, wie auch die Gefahr der Wasserstoffversprödung im Vergleich zur herkömmlichen Methode stark reduziert wird.The advantages which can be achieved with the invention consist in particular in that the galvanic coating of endless strips of any circumferential length is made possible and the limitation to the maximum sizes predetermined by the bath is thus eliminated. This goes hand in hand with the fact that the need for electrolytes is greatly reduced and the required current intensity at the expense of Chrome plating time can be reduced. If only one surface of the endless belt is to be coated, then it is no longer necessary to cover the back of the belt, as in the conventional methods. It has also been shown that both the deposition of a uniform, thick layer succeeds and the risk of hydrogen embrittlement is greatly reduced compared to the conventional method.

Bevorzugte Ausführungsformen der Erfindung sind in den Zeichnungen dargestellt und werden im folgenden näher beschrieben. Es zeigen

  • Fig. 1 schematisch die Seitenansicht einer Doppelbandpresse,
  • Fig. 2 eine Vorrichtung zum Verchromen eines Pressbandes in perspektivischer Ansicht,
  • Fig. 3 eine Dichtung zum Aufstellen eines Pressbandes auf der Grundplatte,
  • Fig. 4 einen Schnitt durch den Mast zur Stromzuführung,
  • Fig. 5 eine Ausführungsform einer Vorrichtung zum gleichzeitigen Verchromen zweier Pressbänder in perspektivischer Ansicht und
  • Fig. 6 einen Teilschnitt durch eine Vorrichtung zum gleichzeitigen Verchromen beider Oberflächen eines Pressbandes.
Preferred embodiments of the invention are shown in the drawings and are described in more detail below. Show it
  • 1 schematically shows the side view of a double belt press,
  • 2 shows a device for chrome-plating a press belt in a perspective view,
  • 3 shows a seal for setting up a press belt on the base plate,
  • 4 shows a section through the mast for power supply,
  • Fig. 5 shows an embodiment of a device for simultaneous chrome plating of two press belts in a perspective view
  • Fig. 6 is a partial section through a device for simultaneous chrome plating of both surfaces of a press belt.

Die in Fig. 1 dargestellte Doppelbandpresse 1 besitzt vier in einem Pressengestell gelagerte Umlenktrommeln 2, 3, 4, 5. Das Pressengestell ist in der Zeichnung der Übersichtlichkeit halber weggelassen. Um jeweils zwei der Umlenktrommein, die sich entsprechend der Pfeile in den Umlenktrommeln 2 und 3 drehen, ist ein pressband 6, 7 herumgeführt, das mit Hydraulikzylindem 8 gespannt wird. Zwischen den Pressbändem wird eine in der Zeichnung von rechts nach links vorlaufende Werkstoffbahn 9, die aus mit Kunstharz getränkten Schichtstoffen, Faser-Bindemittelgemischen oder dergleichen bestehen kann, unter gleichzeitiger Anwendung von Wärme und Druck verdichtet.The double belt press 1 shown in FIG. 1 has four deflection drums 2, 3, 4, 5 mounted in a press frame. The press frame is omitted in the drawing for the sake of clarity. A press belt 6, 7, which is tensioned with hydraulic cylinders 8, is guided around two of the deflecting drums, which rotate according to the arrows in the deflecting drums 2 and 3. Between the press belts, a material web 9 leading from right to left in the drawing, which can consist of laminates impregnated with synthetic resin, fiber-binder mixtures or the like, is compressed with simultaneous application of heat and pressure.

Der auf die Werkstoffbahn 9 ausgeübte Druck wird über Druckplatten 10, 11 hydraulisch oder mechanisch auf die Innenseiten der Pressbänder 6, 7 aufgebracht und von dort auf die Werkstoffbahn übertragen. Bei der hydraulischen Druckübertragung wird in dem Raum 12, der nach oben und unten von der Druckplatte 10 bzw. der Pressbandinnenseite 6 und zu den Seiten von der Dichtung 13 begrenzt wird, ein unter Druck setzbares, fluides Druckmedium, beispielsweise Öl oder Luft, eingebracht. Zur mechanischen Druckübertragung sind zwischen der Druckplatte 11 und der pressbandinnenseite 7 ortsfeste Rollen 14 angebracht. Mit Hilfe von Hydraulikzylindem 60 wird die Druckplatte 11 und damit die Rollen 14 gegen die Innenseite des pressbandes 7 angestellt..The pressure exerted on the material web 9 is applied hydraulically or mechanically to the inner sides of the press belts 6, 7 via pressure plates 10, 11 and transmitted from there to the material web. In the case of hydraulic pressure transmission, a fluid pressure medium which can be pressurized, for example oil or air, is introduced into the space 12, which is delimited at the top and bottom by the pressure plate 10 or the inside of the press belt 6 and on the sides by the seal 13. For mechanical pressure transmission, 7 fixed rollers 14 are attached between the pressure plate 11 and the inside of the press belt. With the help of hydraulic cylinders 60, the pressure plate 11 and thus the rollers 14 are set against the inside of the press belt 7.

Das pressband 6 bzw. 7 ist ein endloses, aus einer hochzugfesten Stahlsorte bestehendes Band, das im entspannten Zustand eine ringförmige Gestalt besitzt. Damit es bei dem auf die Werkstoffbahn 9 auszuübenden Druck nicht innerhalb kurzer Zeit zerstört wird, muss die Oberfläche des Pressbandes eine hohe Härte besitzen. Üblicherweise wird die benötigte Härte durch galvanisches Hartverchromen der Oberfläche mit Schichtdicken von 30 bis 100 Mikrometer erreicht.The press belt 6 or 7 is an endless belt made of a high-tensile steel grade, which in the relaxed state has an annular shape. In order that the pressure to be exerted on the material web 9 is not destroyed within a short time, the surface of the press belt must have a high hardness. The required hardness is usually achieved by galvanic hard chrome plating of the surface with layer thicknesses of 30 to 100 micrometers.

Die Fig. 2 zeigt eine erfindungsgemässe Vorrichtung zum galvanischen Aufbringen einer Hartchromschicht auf die Innenseite des endlosen Pressbandes 15. Die Vorrichtung besteht aus einer rechteckigen Grundplatte 16 aus Stahl, deren Fläche so bemessen ist, dass sie das grösste zu verchromende pressband aufnehmen kann. Entsprechend dem erfindungsgemässen Verfahren ist auf dieser Grundplatte 16 das Pressband 15 hochkant im ungespannten Zustand, womit es einen kreisförmigen Ring bildet, in einer auf der Grundplatte aufliegenden Ringdichtung 17 aufgestellt. Im Innem dieses pressbandes 15 ist ein weiteres Pressband 15a ebenfalls auf einer in der Zeichnung verdeckt liegenden Ringdichtung 17 aufgestellt. Dieses pressband 15a besitzt einen kleineren Durchmesser als das äussere Pressband 15 und ist konzentrisch zum Pressband 15 angeordnet. Die beiden Pressbänder 15 und 15a besitzen dieselbe Breite bzw. im hochkant gestellten Zustand dieselbe Höhe, so dass zwischen der Innenfläche 18 des äusseren Pressbandes 15 und der Aussenfläche 19 des inneren Pressbandes 15a ein ringförmiger Hohlraum 21 entsteht. In diesem Hohlraum befindet sich der Elektrolyt, gewöhnlicherweise Chromsäure.2 shows a device according to the invention for the galvanic application of a hard chrome layer to the inside of the endless press belt 15. The device consists of a rectangular base plate 16 made of steel, the area of which is dimensioned such that it can hold the largest press belt to be chromed. In accordance with the method according to the invention, the press belt 15 is placed upright on this base plate 16 in the untensioned state, with which it forms a circular ring, in an annular seal 17 resting on the base plate. Inside this press belt 15, another press belt 15a is also placed on an annular seal 17, which is hidden in the drawing. This press belt 15a has a smaller diameter than the outer press belt 15 and is arranged concentrically with the press belt 15. The two press belts 15 and 15a have the same width or, in the upright state, the same height, so that an annular cavity 21 is formed between the inner surface 18 of the outer press belt 15 and the outer surface 19 of the inner press belt 15a. The electrolyte, usually chromic acid, is in this cavity.

Die beiden Bänder 15 und 15a werden mittels Spannelementen 20 bzw. Gegenspannelementen 54 fest auf der Grundplatte 16 aufgespannt, so dass ihre ringförmige Anordnung und ihre relative Lage zueinander während des Verchromungsvorgangs fest vorgegeben sind. Die Spannelemente 20 sind dabei so angebracht, dass sie ausserhalb des Hohlraums 21 stehen. Das innere Band 15a wird von der Innenseite aus mit Gegenspannelementen 54 zu einer kreisrunden Form gespannt. Im Mittelpunkt der durch die zwei Bänder 15 und 15a festgelegten konzentrischen Kreise befindet sich ein auf der Grundplatte stehender, mit dieser verschraubter Mast 22. Durch eine lsolierungs- platte 23 aus Kunststoff herrscht zwischen dem Mast 22 und der Grundplatte 16 keine elektrisch leitende Verbindung.The two bands 15 and 15a are clamped firmly on the base plate 16 by means of clamping elements 20 or counter-clamping elements 54, so that their annular arrangement and their relative position to one another are fixed during the chromium plating process. The clamping elements 20 are attached so that they are outside the cavity 21. The inner band 15a is tensioned from the inside with counter-tensioning elements 54 into a circular shape. At the center of the concentric circles defined by the two bands 15 and 15a is a mast 22 which stands on the base plate and is screwed thereto . An insulating plate 23 made of plastic means that there is no electrically conductive connection between the mast 22 and the base plate 16.

Auf diesem Mast ist eine drehbar gelagerte Aussenhülse 24 angebracht. Diese Aussenhülse 24 trägt zwei einen Winkel von 180 Grad bildende Arme 25 aus Kupfer, deren Länge grösser als der Radius des inneren Bandes 15a und kleiner als der Radius des äusseren Bandes 15 ist. Die Arme 25 sind in einer solchen Höhe angebracht, dass sie die beiden Pressbänder 15 und 15a überragen. An den Enden der beiden Arme 25 sind mehrere Bleistangen 26 befestigt, die in den Hohlraum 21 bis fast auf die Grundplatte 16 hineinreichen. Durch die entsprechend gewählte Länge der Arme 25 besitzen die Bleistangen 26 sowohl von der Innenfläche 18 des pressbandes 15 wie auch von der Aussenfläche 19 des pressbandes 15a einen gewissen Abstand und berühren daher diese Flachen auch bei Drehung der Aussenhülse 24 und damit der Arme 25 nicht.A rotatably mounted outer sleeve 24 is attached to this mast. This outer sleeve 24 carries two arms 25 made of copper, forming an angle of 180 degrees, the length of which is greater than the radius of the inner band 15a and smaller than the radius of the outer band 15. The arms 25 are mounted at a height such that they protrude beyond the two press belts 15 and 15a. At the ends of the two arms 25, a plurality of pencils 26 are attached, which extend into the cavity 21 almost to the base plate 16. Due to the appropriately selected length of the arms 25, the pencils 26 have a certain distance both from the inner surface 18 of the press belt 15 and from the outer surface 19 of the press belt 15a and therefore do not touch these surfaces even when the outer sleeve 24 and thus the arms 25 are rotated.

Auf der Aussenfläche des Pressbandes 15 sind mehrere ringförmige aus Kupfer bestehende Manschetten 27 über die Höhe des Pressbandes 15 verteilt so angebracht, dass in der Nähe des oberen und unteren Randes des Pressbandes sich jeweils eine Manschette 27 befindet. Diese Manschetten werden durch die Spannelemente 20 in ihrer Lage fixiert gehalten. Die Spannelemente 20 sind gegenüber der Grundplatte 16 elektrisch isoliert angebracht. Da das Band 15 auf einer Ringdichtung 17 aus Gummi oder Kunststoff aufliegt, besitzt es ebenfalls keinen elektrischen Kontakt zur Grundplatte 16.Are on the outer surface of the press belt 15 a plurality of annular cuffs 27 made of copper distributed over the height of the press belt 15 so that a sleeve 27 is located in the vicinity of the upper and lower edge of the press belt. These cuffs are held in their position by the tensioning elements 20. The clamping elements 20 are electrically insulated from the base plate 16. Since the band 15 rests on an annular seal 17 made of rubber or plastic, it likewise has no electrical contact with the base plate 16.

Den Aufbau einer solchen Ringdichtung 17 entsprechend einem Schnitt an der Stelle A in Fig. 2 zeigt Fig. 3. Diese Dichtung besteht aus einem, ringförmigen Körper 42, der auf der Grundplatte 16 aufliegt. Der Körper 42 besteht aus einem elektrisch nichtleitenden Material wie Gummi oder Kunststoff. Auf der Oberseite des Körpers 42 befindet sich eine ringförmige Nut 43, in der eine Halterung 44 fest eingesteckt ist. Diese Halterung 44 wiederum besteht aus zwei Teilen, nämlich zwei ringförmigen Eisenschienen 45 und 46. Eine der Eisenschienen 45 besitzt in ihrem oberen Teil einen Absatz 48 und eine daran anschliessende Nut 49. Das pressband 15 wird nun so in die Halterung 44 gestellt, dass es auf dem Absatz 48 der Eisenschiene 45 aufsteht und mit dem unteren Teil der einen Fläche an der Wandung 50 der zweiten Eisenschiene 46 anliegt. In der Nut 49 befindet sich ein O-Ring 51, der das Pressband 15 gegen die Wandung 50 presst. Der Anpressdruck kann noch gesteigert werden, indem man in der Nut 49 auf den O-Ring 51 eine unter Druck stehende Flüssigkeit, beispielsweise Wasser oder die Elektrolytflüssigkeit selbst, wirken lässt Dadurch wird gewährleistet, dass das Pressband 15 sowohl fest und gegen den im Hohlraum 21 befindlichen Elektrolyten dichtend auf der Grundplatte 16 aufliegt, als auch elektrisch gegen die Grundplatte isoliert istThe structure of such an annular seal 17 corresponding to a section at point A in FIG. 2 is shown in FIG. 3. This seal consists of an annular body 42 which rests on the base plate 16. The body 42 is made of an electrically non-conductive material such as rubber or plastic. On the top of the body 42 there is an annular groove 43 in which a holder 44 is firmly inserted. This holder 44 in turn consists of two parts, namely two annular iron rails 45 and 46. One of the iron rails 45 has a shoulder 48 in its upper part and a groove 49 adjoining it. The press belt 15 is now placed in the holder 44 in such a way that it stands on the shoulder 48 of the iron rail 45 and rests with the lower part of one surface on the wall 50 of the second iron rail 46. In the groove 49 there is an O-ring 51 which presses the press belt 15 against the wall 50. The contact pressure can be increased further by allowing a pressurized liquid, for example water or the electrolyte liquid itself, to act in the groove 49 on the O-ring 51. This ensures that the press belt 15 is both firm and against the one in the cavity 21 located electrolyte sealingly rests on the base plate 16, and is also electrically insulated from the base plate

Der geschilderte Dichtungsaufbau nach Fig. 3 besitzt den Vorteil, dass durch die sehr starre Einspannung des Pressbandes 15 im unteren Bandteil ein sicherer ringförmiger Stand des Pressbandes auf der Grundplatte 16 gewährleistet ist Unter Umständen kann dann sogar auf die Spannelemente 20 oder Gegenspannelemente 54 verzichtet werden und das Pressband 15 frei auf der Grundplatte 16 aufgestellt werden. Selbstverständlich kann bei der Verwendung der Spannelemente 20 bzw. 54 auch auf eine einfachere Dichtung zurückgegriffen werden, da dann die Dichtung keine Spannfunktion ausüben muss. Es genügt dann beispielsweise die Abdichtung der Fuge zwischen pressband 15 und Grundplatte 16 mittels eines Silikonringes.3 has the advantage that due to the very rigid clamping of the press belt 15 in the lower belt part, a secure annular position of the press belt on the base plate 16 is ensured. Under certain circumstances, the tensioning elements 20 or counter-tensioning elements 54 can even be dispensed with and the press belt 15 can be placed freely on the base plate 16. Of course, a simpler seal can also be used when using the tensioning elements 20 or 54, since the seal then does not have to perform a tensioning function. It is then sufficient, for example, to seal the joint between the press belt 15 and the base plate 16 by means of a silicone ring.

Zur galvanischen Hartverchromung der Innenfläche 18 des äusseren Bandes 15 werden entsprechend dem erfindungsgemässen Verfahren die Manschetten 27 über flexible Leitungen 52 an eine aus Kupferstäben mit genügend grossem Leitungsquerschnitt bestehende Ringleitung 64 angeschlossen, die ihrerseits wiederum mit dem negativen Pol einer Gleichspannungsquelle verbunden ist. Die Bleistangen 26 werden über die Arme 25 und dem Mast 22, der wiederum durch die Grundplatte 16 hindurch kontaktiert ist, mit dem positiven Pol der Gleichspannungsquelle verbunden. Damit ist das äussere Band 15 als Kathode geschaltet und die Bleistangen 26 als Anode. Mittels eines Motors 28 und einer Kette 53 zur Kraftübertragung auf ein an der Aussenhülse 24 befestigtes Zahnrad 55 wird die Aussenhülse 24 des Mastes 22 angetrieben, so dass die als Anode wirkenden Bleistangen 26 mit gleichförmiger Geschwindigkeit rotieren. Gemäss dem bekannten galvanischem Prinzip scheiden sich aus dem Elektrolyten im Hohlraum 21 nun Chromatome auf der der Anode 26 gegenüberliegenden Steile der Innenfläche 18 des als Kathode wirkenden Pressbandes 15 ab. Da sich die Anode 26 drehend bewegt, scheidet sich pro Umlauf eine Chromschicht mit einer bestimmten Dicke auf der gesamten Innenfläche 18 ab. Durch entsprechende Wahl der Anzahl der Umläufe der Anode 26 wird die gewünschte Gesamtschichtdicke der Hartchromschicht erhalten.For the galvanic hard chrome plating of the inner surface 18 of the outer band 15, according to the method according to the invention, the sleeves 27 are connected via flexible lines 52 to a ring line 64 consisting of copper rods with a sufficiently large line cross section, which in turn is connected to the negative pole of a DC voltage source. The pencils 26 are connected to the positive pole of the DC voltage source via the arms 25 and the mast 22, which in turn is contacted through the base plate 16. The outer band 15 is thus connected as the cathode and the pencils 26 as the anode. The outer sleeve 24 of the mast 22 is driven by means of a motor 28 and a chain 53 for transmitting power to a gear 55 fastened to the outer sleeve 24, so that the pencils 26 acting as anode rotate at a uniform speed. According to the known galvanic principle, chromium atoms are now deposited from the electrolyte in the cavity 21 on the part of the inner surface 18 of the press belt 15 which acts as the cathode and is opposite the anode 26. Since the anode 26 rotates, a chrome layer with a certain thickness is deposited on the entire inner surface 18 per revolution. The desired total layer thickness of the hard chrome layer is obtained by appropriate selection of the number of revolutions of the anode 26.

Eine Vergrösserung der abgeschiedenen Schichtdicke pro Umlauf ist möglich, indem die Anzahl der nebeneinanderliegenden Bleistangen 26, die die Anode bilden, erhöht wird. Bei sehr vielen nebeneinanderliegenden Bleistangen ist darauf zu achten, dass diese so angebracht werden, dass sie im Querschnitt gesehen die Form eines Kreisausschnittes besitzen, damit gewährleistet wird, dass sie bei der Rotation der Aussenhülse 24 nirgends mit einer Fläche 18, 19 der Bänder kollidieren. Eine andere Massnahme zur Vergrösserung der abgeschiedenen Schichtdicke besteht darin, mehr als zwei Arme 25 mit den daran befestigten Anoden auf der Aussenhülse 24 anzubringen. Bei diesen Massnahmen ist zu beachten, dass die Stromstärke entsprechend ansteigt und die Leistung der Gleichspannungsquelle dafür ausgelegt sein muss. Selbstverständlich kann bei geringer Leistung der Gleichspannungsquelle auch nur ein Arm 25 mit Anode an der Aussenhülse 24 angebracht sein, wobei dann die Anzahl der Umläufe für eine bestimmte Gesamtschichtdicke ansteigt.An increase in the deposited layer thickness per revolution is possible by increasing the number of adjacent pencils 26 which form the anode. In the case of a large number of pencils lying next to one another, care must be taken that they are attached in such a way that they have the shape of a circular section when viewed in cross-section, so that it is ensured that they do not collide with a surface 18, 19 of the strips when the outer sleeve 24 rotates. Another measure for increasing the deposited layer thickness consists in attaching more than two arms 25 with the anodes attached to them on the outer sleeve 24. With these measures, it should be noted that the current strength increases accordingly and the power of the DC voltage source must be designed for this. Of course, with low power of the DC voltage source, only one arm 25 with an anode can be attached to the outer sleeve 24, in which case the number of cycles for a certain total layer thickness increases.

Die Dimensionierung der Gleichspannungsquelle, die üblicherweise durch einen Netztransformator mit anschliessendem Gleichrichter dargestellt wird, erfolgt nach den bekannten Gesetzen der Elektrolyse. Die Eigenschaften der abgeschiedenen Chromschicht hängen, wie in der Galvanik allgemein bekannt, empfindlich von der Temperatur des Elektrolyten und der Stromdichte ab. Die Temperatur des Elektrolyten im Hohlraum 21 wird daher mittels im Hohlraum angebrachter Temperaturfühler ständig kontrolliert und durch Zufuhr von erwärmten Elektrolyten konstant gehalten. Die Zufuhr von frischem Elektrolyten erfolgt von unten durch die Grundplatte 16 hindurch in den Hohlraum 21. Gleichzeitig wird damit der verbrauchte Elektrolyt ersetzt, da durch die Abscheidung der Chromionen auf der Bandoberfläche dessen Konzentration entsprechend abnimmt. Somit ist sowohl die Temperatur wie auch Konzentration des Elektrolyten über den gesamten Galvanisierungszeitraum konstant.The dimensioning of the DC voltage source, which is usually represented by a mains transformer with a subsequent rectifier, is carried out according to the known laws of electrolysis. The properties of the deposited chrome layer, as is generally known in electroplating, are sensitive to the temperature of the electrolyte and the current density. The temperature of the electrolyte in the cavity 21 is therefore constantly checked by means of temperature sensors mounted in the cavity and kept constant by supplying heated electrolytes. Fresh electrolyte is supplied from below through the base plate 16 into the cavity 21. At the same time, the used electrolyte is replaced because the concentration of the chromium ions on the strip surface decreases accordingly. So both the temperature as well Concentration of the electrolyte constant over the entire electroplating period.

Durch die ringförmige Anordnung der Kathode und Anode wird die Stromdichte ebenfalls automatisch an allen Stellen konstant gehalten, so dass man insgesamt eine sehr gleichmässige Schichtdicke der Hartchromschicht auf der gesamten Bandoberfläche erhält. Es hat sich auch gezeigt, dass eine Wasserstoffversprödung kaum auftritt, womit die Gefahr des Zerspringens der Oberflächenschicht unter Zugspannungen gebannt wird. Die Biegewechselfestigkeit der nach dem erfindungsgemässen Verfahren verchromten Bänder liegt ebenfalls weit höher als diejenige konventionell verchromter Bänder.Due to the ring-shaped arrangement of the cathode and anode, the current density is also automatically kept constant at all points, so that overall a very uniform layer thickness of the hard chrome layer is obtained on the entire strip surface. It has also been shown that hydrogen embrittlement hardly occurs, thus eliminating the risk of the surface layer cracking under tensile stress. The flexural fatigue strength of the strips chrome-plated by the method according to the invention is also far higher than that of conventionally chrome-plated strips.

Die Stromausbeuten bei der Hartverchromung liegen bei ungefähr 20 %, d. h. rund 80 % des benötigten Stromes wird zur Elektrolyse von Wasser verwendet. Damit entwickelt sich an der Kathode gasförmiger Wasserstoff, der aus dem Hohlraum 21 entweicht. Die aufsteigenden Gasblasen reissen dabei einen Teil des Elektrolyten mit, womit das Wasserstoffgas mit Chromsäuredampf vermischt ist. Vorteilhafterweise kann über die gesamte Bänderanordnung ein aus Plastikfolie bestehendes Zeit gespannt werden, wie in Fig.5 schematisch mit dem Bezugszeichen 30 angedeutet ist, in dem diese Dämpfe aufgefangen und abgesaugt werden.The current yields in hard chrome plating are approximately 20%, i.e. H. Around 80% of the electricity required is used for the electrolysis of water. This produces gaseous hydrogen at the cathode, which escapes from the cavity 21. The rising gas bubbles entrain part of the electrolyte, with which the hydrogen gas is mixed with chromic acid vapor. Advantageously, a time consisting of plastic film can be stretched over the entire belt arrangement, as indicated schematically in FIG. 5 by the reference numeral 30, in which these vapors are collected and extracted.

Um die Verlustleistungen so gering wie möglich zu machen, müssen die Zuleitungen des Stromes zur Anode und Kathode mit geringstmöglichem Widerstand erfolgen. Es werden daher wie in der Galvanik üblich Leitungen aus massivem Kupfer mit entsprechend grossem Querschnitt verwendet. Da sich die Anode 26 während der Galvanisierung bewegt, besitzt die Zuführung des Stromes im Mast 22 eine besondere Ausgestaltung, die in Fig. 4 im Querschnitt zu sehen ist.In order to make the power losses as low as possible, the supply lines of the current to the anode and cathode must be made with the lowest possible resistance. Therefore, as is common in electroplating, lines made of solid copper with a correspondingly large cross section are used. Since the anode 26 moves during the galvanization, the supply of the current in the mast 22 has a special configuration, which can be seen in cross section in FIG. 4.

Der Mast 22 besteht aus einem hohlen Vierkantrohr 56, das mittels eines Bodenflansches 31 über eine Kunststoffplatte 23 elektrisch isoliert auf der Grundplatte 16 aufgeschraubt ist. In dem Vierkantrohr verläuft eine Kupferstange 32, die über eine Öffnung in der Grundplatte 16 mit der Stromzuführung von der Gleichspannungsquelle kontaktiert ist. Diese Kupferstange 32 schliesst an ihrem oberen Ende mit einem Flansch 33 ab, auf dem ein äusserer Ringflansch 34 und ein innerer Ringflansch 35 so montiert sind, dass zwischen beiden ein ringförmiger Hohlraum frei bleibt. Zwischen dem hohlen Vierkantrohr 56 und dem Flansch 33 besteht keine leitende Verbindung, da gemeinsame Kontaktstellen mit Isolierungen 62 versehen sind. Die Aussenhülse 24 besitzt in ihrem unteren Teil einen ringförmigen Gegenflansch 39 und eine in der Mitte verlaufende Welle 36. Diese Welle 36 reicht in den vom inneren Ringflansch 35 gebildeten Hohlraum 57 und ist dort mittels zweier Kugellager 38 drehbar auf dem inneren Ringflansch 35 befestigt, so dass sich diese Welle und mit ihr die gesamte Aussenhülse 24 um die feststehende Kupferstange 32 drehen kann. Die Kugellager 38 sind mittels einer aus Kunststoff bestehenden Isolierung 37 gegen den inneren Ringflansch 35 isoliert. Der Abstand beider Kugellager 38 wird durch eine obere Distanzhülse 58 fixiert, während das untere Kugellager über eine untere Distanzhülse 59 auf einer Isolierungsplatte 40 aufliegt, die wiederum auf dem Flansch 33 liegt.The mast 22 consists of a hollow square tube 56 which is screwed onto the base plate 16 in an electrically insulated manner by means of a base flange 31 and a plastic plate 23. A copper rod 32 runs in the square tube and is in contact with the power supply from the DC voltage source via an opening in the base plate 16. This copper rod 32 terminates at its upper end with a flange 33 on which an outer ring flange 34 and an inner ring flange 35 are mounted in such a way that an annular cavity remains free between the two. There is no conductive connection between the hollow square tube 56 and the flange 33, since common contact points are provided with insulation 62. The outer sleeve 24 has in its lower part an annular counter flange 39 and a shaft 36 running in the middle. This shaft 36 extends into the cavity 57 formed by the inner ring flange 35 and is rotatably fastened there on the inner ring flange 35 by means of two ball bearings 38, so that this shaft and with it the entire outer sleeve 24 can rotate about the fixed copper rod 32. The ball bearings 38 are insulated from the inner ring flange 35 by means of an insulation 37 made of plastic. The distance between the two ball bearings 38 is fixed by an upper spacer sleeve 58, while the lower ball bearing rests on an insulating plate 40 via a lower spacer sleeve 59, which in turn lies on the flange 33.

Der ringförmige Gegenflansch 39 der Aussenhülse 24 reicht in den durch den inneren Ringflansch 34 und äusseren Ringflansch 35 gebildeten Hohlraum so hinein, dass zwischen den Wänden ein geringfügiges Spiel von einigen 1/10 mm bleibt. Dieser durch das Spiel vorgegebene Raum ist durch Quecksilber 61, das elektrisch gut leitet, ausgefüllt und gewährleistet die Stromübertragung vom Flansch 33 über die feststehenden Ringflansche 34 und 35 auf den drehbaren Gegenflansch 39 der Aussenhülse 24 und von dort über die Arme 25, die am oberen Teil der Aussenhülse 24 montiert sind, weiter auf die Anode 26.The annular counter flange 39 of the outer sleeve 24 extends into the cavity formed by the inner ring flange 34 and outer ring flange 35 in such a way that a slight play of a few 1/10 mm remains between the walls. This space determined by the game is filled with mercury 61, which conducts electricity well, and ensures the current transmission from the flange 33 via the fixed ring flanges 34 and 35 to the rotatable counter flange 39 of the outer sleeve 24 and from there via the arms 25, which are at the top Part of the outer sleeve 24 are mounted on the anode 26th

Auf der Aussenhülse 24 ist ein Zahnrad 55 montiert, das über die Kette 53 vom Motor 28 angetrieben wird und die Drehung der Aussenhülse bewirkt. Der Motor 28 wiederum ist am Vierkantrohr 56 befestigt Damit kein Strom von der Aussenhülse 24 über die Kette 53 auf den Motor 28 und das Vierkantrohr 56 fliesst, ist das Zahnrad mittels Isolierfolien 41 elektrisch gegen die Aussenhülse isoliert. Durch diesen Aufbau wird auch weiter erreicht, dass kein Strom vom inneren Ringflansch 35 über die Kugellager 38 auf die Welle 36 fliesst, da die bei der Verchromung benötigten grossen Ströme an den kleinen Querschnitten der Kugellager sonst gefährliche Überhitzungen verursachen könnten. Die Welle 36 selbst besitzt einen geringen Abstand zur lsolierungsplatte 40 und damit zu dem Flansch 33.A gear 55 is mounted on the outer sleeve 24, which is driven by the motor 28 via the chain 53 and causes the outer sleeve to rotate. The motor 28 is in turn attached to the square tube 56 so that no current flows from the outer sleeve 24 via the chain 53 to the motor 28 and the square tube 56, the gearwheel is electrically insulated from the outer sleeve by means of insulating foils 41. This construction also ensures that no current flows from the inner ring flange 35 via the ball bearings 38 to the shaft 36, since the large currents required for the chrome plating could otherwise cause dangerous overheating on the small cross sections of the ball bearings. The shaft 36 itself is at a short distance from the insulation plate 40 and thus from the flange 33.

Soll nun anstelle der inneren Oberfläche eines Pressbandes dessen Aussenfläche verchromt werden, so werden die Bänder auf der Vorrichtung so angeordnet, dass das Band mit dem kleineren Durchmesser als Kathode geschaltet wird. In Fig. 2 ist dies das Pressband 15a mit der zu verchromenden Oberfläche 19. Die Verbindung der Kathode mit dem negativen Pol der Spannungsquelle erfolgt nun über Zuleitungen auf die Innenseite des Pressbandes 15a, entsprechend der obigen Beschreibung, während die Anode weiterhin mit den Bleistangen 26 verbunden ist. Ansonsten bleibt die Anordnung unverändert. Die Chromatome aus dem im Hohlraum 21 befindlichen Elektrolyten scheiden sich dann bei eingeschalteter Spannungsquelle und rotierenden Armen 25 auf der Aussenfläche 19 des pressbandes 15a ab und bilden die gewünschte Chromschicht.If instead of the inner surface of a press belt should be chrome-plated, the belts are arranged on the device in such a way that the belt with the smaller diameter is switched as the cathode. 2, this is the press belt 15a with the surface 19 to be chrome-plated. The connection of the cathode to the negative pole of the voltage source now takes place via leads to the inside of the press belt 15a, as described above, while the anode continues with the pencils 26 connected is. Otherwise the arrangement remains unchanged. The chromium atoms from the electrolyte located in the cavity 21 then separate with the voltage source switched on and the arms 25 rotating on the outer surface 19 of the press belt 15a and form the desired chromium layer.

Mit der erfindungsgemässen Vorrichtung lassen sich auch vorteilhafterweise zwei Pressbänder gleichzeitig verchromen, wobei dann bei dem aussenliegenden Band die Innenseite und bei dem innenliegenden Band die Aussenseite verchromt wird. Dazu werden auf der Innenseite des innenliegenden Bandes 15a Manschetten angebracht entsprechend den Manschetten 27 des aussenliegenden Bandes. Die Manschetten 27 werden sowohl auf dem äusseren Band 15 wie auch inneren Band 15a mit Spannelementen 20 festgehalten, die wie in Fig. 5 gezeigt, aus Kupferstangen bestehen und in diesem Ausführungsbeispiel gleichzeitig der Stromzuführung dienen. Ansonsten ist die in Fig. 5 gezeigte Vorrichtung gleich aufgebaut wie diejenige in Fig. 2, ausgenommen dass hier die Kraftübertragung vom Motor 28 auf die Aussenhülse 24 über ein Getriebe 29 mit passend gewählter Untersetzung erfolgt. Die zu Fig. 2 identischen Teile werden in Fig. 5 mit demselben Bezugszeichen bezeichnet.With the device according to the invention it is also advantageously possible to chrome-plate two press belts at the same time, the inside of the belt lying on the outside and the outside of the belt lying on the inside being chrome-plated. For this purpose, cuffs are attached to the inside of the inside band 15a corresponding to the cuffs 27 of the outside band. The cuffs 27 are both on the outer band 15 and the inner band 15a with tensioning elements 20 held, which, as shown in Fig. 5, consist of copper rods and serve in this embodiment at the same time the power supply. Otherwise, the device shown in FIG. 5 is constructed in the same way as that in FIG. 2, except that here the power transmission from the motor 28 to the outer sleeve 24 takes place via a gear 29 with a suitably selected reduction ratio. The parts identical to FIG. 2 are designated in FIG. 5 with the same reference numerals.

Sowohl die Manschetten des aussenliegenden Bandes 15 wie auch diejenigen des innenliegenden Bandes werden mit dem negativen Pol der Spannungsquelle verbunden, so dass beide Bändem nun gleichzeitig die Kathode bilden. Rotieren die Arme 25 mit den als Anode wirkenden Bleistangen 26, so scheiden sich Chromatome sowohl auf der Innenfläche 18 des äusseren Bandes 15 als auch auf der Aussenfläche 19 des inneren Bandes 15a ab. Damit wird also je eine Oberfläche beider Bänder mit einer Chromschicht bedeckt. Bei der Dimensionierung der Spannungsquelle muss dann selbstverständlich der höhere Strombedarf beachtet werden.Both the sleeves of the outside band 15 and those of the inside band are connected to the negative pole of the voltage source, so that both bands now form the cathode at the same time. If the arms 25 rotate with the pencils 26 acting as an anode, chromium atoms are deposited both on the inner surface 18 of the outer band 15 and on the outer surface 19 of the inner band 15a. This means that one surface of each band is covered with a chrome layer. When dimensioning the voltage source, the higher current requirement must of course be taken into account.

Eine weitere Ausbildung des Verfahrens ermöglicht die gleichzeitige Verchromung der innenwie der Aussenfläche eines einzigen Pressbandes 15b. Dazu werden drei Pressbänder 15, 15b und 15a mit abnehmenden Durchmessern konzentrisch ineinander auf der Grundplatte 16 aufgestellt. Fig. 6 zeigt einen Schnitt in Richtung des Durchmessers zum gemeinsamen Mittelpunkt durch die Wandungen der drei ineinanderliegenden Pressbänder. Diese drei Pressbänder stehen auf Dichtungen 17, 17b und 17a, wobei die Dichtungen 17 und 17a entsprechend der in Fig.3 gezeigten Dichtung aufgebaut sind, so dass auf zusätzliche Spannelemente für die Pressbänder verzichtet werden kann. Falls es zweckmässig erscheint, können das innere 15a und äussere pressband 15 jedoch auch mit den üblichen Spannelementen 20 bzw. 54 gespannt werden, womit sich die Verwendung dieser Dichtung für diese beiden Pressbänder 15, 15a erübrigt.A further development of the method enables the simultaneous chrome plating of the inside and outside surface of a single press belt 15b. For this purpose, three press belts 15, 15b and 15a with decreasing diameters are placed concentrically one inside the other on the base plate 16. Fig. 6 shows a section in the direction of the diameter to the common center through the walls of the three interlocking press belts. These three press belts stand on seals 17, 17b and 17a, the seals 17 and 17a being constructed in accordance with the seal shown in FIG. 3, so that additional tensioning elements for the press belts can be dispensed with. If it appears expedient, the inner 15a and outer press belt 15 can, however, also be tensioned with the usual tensioning elements 20 or 54, which makes the use of this seal for these two press belts 15, 15a unnecessary.

Das mittlere Pressband 15b wird jedoch in einer solchen Dichtung eingespannt, womit dessen Innen- und Aussenflächen zum gleichzeitigen Verchromen nicht verdeckt sind und andrerseits das pressband 15b fixiert auf der Grundplatte 16 steht. Die Dichtung 17b besitzt in ihrem unteren Teil zusätzlich einen in beiden Eisenschienen 45, 46 verlaufenden Zapfenring 47, der aus einem gut leitenden Material wie Kupfer besteht. Dieser Zapfenring 47 ist an mehreren Stellen von unten durch Öffnungen 65 in der Grundplatte 16 durch Kontaktstecker 63 mit dem negativen Pol der Spannungsquelle verbunden, so dass das Band 15b als Kathode geschaltet ist.The middle press belt 15b is, however, clamped in such a seal, so that the inner and outer surfaces thereof are not covered for simultaneous chrome plating, and on the other hand the press belt 15b is fixed on the base plate 16. In its lower part, the seal 17b additionally has a peg ring 47 which runs in both iron rails 45, 46 and which is made of a highly conductive material such as copper. This pin ring 47 is connected at several points from below through openings 65 in the base plate 16 through contact plug 63 to the negative pole of the voltage source, so that the band 15b is connected as a cathode.

Zwischen dem äusseren 15 und mittleren Band 15b besteht ein Hohlraum 21 a und zwischen dem mittleren 15b und inneren Band 15a ein weiterer Hohlraum 21b. In den Hohlraum 21 a taucht eine Anode 26a und in den Hohlraum 21 b eine Anode 26b ein. Beide Anoden 26a und 26b bestehen wiederum aus Bleistangen, die von einem Arm 25 abgehen. Die Ausgestaltung der Anoden und deren Kontaktierung über die Arme 25 und dem Mast 22 erfolgt ansonsten gleich wie weiter oben beschrieben. Beide Hohlräume 21 a und 21 b sind mit dem Elektrolyten gefüllt. Da das äussere Pressband 15 und das innere Pressband 15a potentialfrei sind, entsteht zwischen dem als Kathode wirkenden mittleren pressband 15b und den beiden Teilen 26a und 26b der Anode ein elektrisches Feld, so dass sich bei rotierender Anode und eingeschalteter Spannungsquelle eine Chromschicht gleichzeitig sowohl auf der Aussenals auch auf der Innenoberfläche des Pressbandes 15b abscheidet.There is a cavity 21 a between the outer 15 and middle band 15 b and a further cavity 21 b between the middle 15 b and inner band 15 a. An anode 26a is immersed in the cavity 21a and an anode 26b is immersed in the cavity 21b. Both anodes 26a and 26b in turn consist of pencils that come off an arm 25. The design of the anodes and their contacting via the arms 25 and the mast 22 are otherwise the same as described above. Both cavities 21 a and 21 b are filled with the electrolyte. Since the outer press belt 15 and the inner press belt 15a are potential-free, an electrical field is created between the middle press belt 15b, which acts as the cathode, and the two parts 26a and 26b of the anode, so that when the anode is rotating and the voltage source is switched on, a chrome layer is simultaneously present on both Deposits also on the inner surface of the press belt 15b.

Das Verfahren und die entsprechende Vorrichtung zur Durchführung des Aufgalvanisierens einer Metallschicht ist hier am Beispiel der Hartverchromung eines Pressbandes beschrieben. Selbstverständlich lässt sich sowohl das Verfahren wie auch die Vorrichtung zur Aufgalvanisierung einer beliebigen anderen Metallschicht auf das Pressband verwenden, beispielsweise zum Verkupfern oder Vernickeln.. Dabei sind die beim Galvanisieren für das jeweilige Metall bekannten Bedingungen zu beachten. Unter Umständen muss dann die Anode 26 aus einem besonderen Material bestehen, beispielsweise aus Kupferstangen, falls auf das Pressband eine Kupferschicht galvanisch aufgebracht werden soll. Falls es zweckmässig erscheint, kann anstelle der aus einzelnen Stangen bestehenden Anode 26 auch eine einzige zusammenhängende Fläche für die Anode gewählt werden. Ebenso ist die Elektrolytsorte wie dem Fachmann geläufig zu wählen.The method and the corresponding device for carrying out the electroplating of a metal layer is described here using the example of hard chrome plating of a press belt. Of course, both the method and the device for electroplating any other metal layer onto the press belt can be used, for example for coppering or nickel plating. The conditions known for electroplating for the respective metal must be observed. Under certain circumstances, the anode 26 must then consist of a special material, for example of copper rods, if a copper layer is to be galvanically applied to the press belt. If it appears expedient, instead of the anode 26 consisting of individual rods, a single contiguous surface can also be selected for the anode. Likewise, the type of electrolyte should be chosen as is familiar to the person skilled in the art.

Claims (30)

1. Process for electroplating the inner surface of a metallic endless strip with a metal coating, whereby the strip possesses a ring shape in untensioned condition, particularly for use as a pressure belt in a double-belt press, and whereby the strip connected as a cathode dips together with an anode into an electrolyte which dissociates into ions in aqueous solution, these ions containing the metal atoms to form the coating, with the cathode and anode being connected with the corresponding terminals of a DC power supply, characterized in that two strips with different diameters and approximately the same width are chosen, whereby the strip to be coated possesses the greater diameter, that both strips are placed upright so that the wide side of the strips points in vertical direction and the strip with the smaller diameter lies completely within the strip with the larger diameter, that the space formed between the inner and outer strip is filled with the electrolyte, that the anode possessing the shape of a circle sector in its cross-section is submersed in this space, that the outer strip is connected as the cathode and that the anode rotates at uniform speed along the cathode.
2. Process for electroplating the outer surface of a metallic endless strip with a metal coating, whereby the strip possesses a ring shape in untensioned condition, particularly for use as a pressure belt in a double-belt press, and whereby the strip connected as a cathode dips together with an anode into an electrolyte which dissociates into ions in aqueous solution, these ions containing the metal atoms to form the coating, with the cathode and anode being connected with the corresponding terminals of a DC power supply, characterized in that two strips with different diameters and approximately the same width are chosen, whereby the strip to be coated possesses the smaller diameter, that both strips are placed upright so that the wide side of the strips points in vertical direction and the strip with the smaller diameter lies completely within the strip with the larger diameter, that the space formed between the inner and outer strip is filled with the electrolyte, that the anode possessing the shape of a circle sector in its cross-section is submersed in this space, that the inner strip is connected as the cathode and that the anode rotates at uniform speed along the cathode.
3. Process for electroplating the outer surface of a metallic endless strip with a metal coating and the inner surface of a further strip, whereby lati P the strips possess a ring shape in untensioned condition, particularly for use as pressure belts in a double belt press, whereby both strips connected as cathodes dip together with an anode into an electrolyte which dissociates into ions in aqueous solution, these ions containing the metal atoms to form the coating, with the cathode and anode being connected with the corresponding terminals of a DC power supply, characterized in that two strips with different diameters and approximately the same width are chosen, whereby both strips are positioned upright so that the wide side of the strips points in vertical direction and the strip with the smaller diameter lies completely within the strip with the larger diameter, that the space formed between the inner and outer strip is filled with the electrolyte, that the anode possessing the shape of a circle sector in its cross-section is submersed in this space, that both the inner and outer strips are connected as cathodes and that the anode rotates at uniform speed along the cathodes.
4. Process for electroplating the inner and outer surfaces of a metallic endless strip with a metal coating, whereby the strip possesses a ring shape in untensioned condition, particularly for use as a pressure belt in a double-belt press, and whereby the strip connected as a cathode dips together with an anode into an electrolyte which dissociates into ions in aqueous solution, these ions containing the metal atoms to form the coating, with the cathode and anode being connected with the corresponding terminals of a DC power supply, characterized in that three strips with different diameters in pairs respectively and with approximately the same width are selected, whereby the strip to be coated possesses the middle diameter, that all three strips are positioned upright, so that the wide side of the strips points in vertical direction and so that the strip with the next-smaller diameter lies completely within the strip with the next-larger diameter, that the two spaces produced between the inner and middle strip and the outer and middle strip are filled with the electrolyte, that one anode in each case possessing the shape of a circle sector in its cross-section is submersed in these spaces, that the middle strip is connected as a cathode, while both the outer and inner strip are potential-free, and that the anodes rotate with uniform speed along the cathode.
5. Process in accordance with one of Claims 1 to 3, characterized in that the two ring-shaped strips producing a circle in their cross-section are set up in each other so that they form concentric circles with respect to their circle centers and that the distance between the two strips is constant everywhere.
6. Process in accordance with Claim 4, characterized in that the three ring-shaped strips, which form a circle in their cross-section, are set up in each other so that they lie in concentric circles with respect to their circle center points and so that the distance between two strips in each case is constant.
7. Apparatus for performing the process in accordance with Claim 1 with a bath containing the electrolyte, an anode which dips into the electrolyte and the strip to be coated submersed in the electrolyte, with the strip being connected as a cathode, whereby cathode and anode are connected with the corresponding terminals of a DC power supply, characterized in that the bath with the electrolyte is delimited at the sides by ring shaped, upright strips (15, 15a) and from below by a base plate (16), that a vertical mast (22) is mounted on the base plate (16) at the center of the circle formed by the outer strip and is electrically insulated with respect to this base plate, that arms (25) extend from the mast at a height which is greater than the width of the strip and extend into the space (21) of the bath, in that plane anodes (26) possessing the shape of a circle sector in their cross-sections which are rotatable about the mast (22) by means of the arms (25) reach down from the outermost ends of these arms (25) into the bath almost to its bottom, and that the anodes (26) are connected with the positive terminal of the DC power supply via the arms (25) and the mast (22), while the outer strip is connected with the negative terminal by sleeves (27) contacting its outer sides.
8. Apparatus for performing the process in accordance with Claim 2 with a bath containing the electrolyte, an anode which dips into the electrolyte and the strip to be coated submersed in the electrolyte, with the strip being connected as a cathode, whereby cathode and anode are connected with the corresponding terminals of a DC power supply, characterized in that the bath with the electrolyte is delimited at the sides by ring shaped, upright strips (15, 15a) and from below by a base plate (16), that a vertical mast (22) is mounted on the base plate (16) at the center of the circle formed by the outer strip and is electrically insulated with respect to this base plate, in that arms (25) extend from the mast at a height which is greater than the width of the strip and extend into the space (21) of the bath, in that plane anodes (26) possessing the shape of a circle sector in their cross-sections which are rotatable about the mast (22) by means of the arms (25) reach down from the outermost ends of these arms (25) into the bath almost to its bottom, and that the anodes (26) are connected with the positive terminal of the DC power supply via the arms (25) and the mast (22), while the inner strip is connected with the negative terminal by sleeves (27) contacting its inner sides.
9. Apparatus for performing the process in accordance with Claim 3 with a bath containing the electrolyte, an anode which dips into the electrolyte and the strips to be coated submersed in the electrolyte, which are connected as cathodes, whereby cathode and anode are connected with the corresponding terminals of a DC power supply, characterized in that the bath with the electrolyte is delimited at the sides by ring shaped, upright strips (15, 15a) and from below by a base plate (16), that a vertical mast (22) is mounted on the base plate at the common center point of the circle formed by the inner an outer strips an is electrically insulated with respect to this base plate, in that arms (25) extend from the mast at a height which is greater than the width of the strips and extend into the space (21) of the bath, in that plane anodes (26) possessing the shape of a circle sector in their cross-sections which are rotatable about the mast (22) by means of the arms (25) reach down from the outermost ends of these arms (25) into the bath almost to its bottom, and that the anodes (26) are connected with the positive terminal of the DC power supply via the arms (25) and the mast (22), and that both the inner strip (15a), by means of sleeves contacting its inner sides, and the outer strip (15), by means of sleeves (27) contacting its outer sides, are connected with the negative terminal.
10. Apparatus for performing the process in accordance with Claim 4 with a bath containing the electrolyte, an anode which dips into the electrolyte and the strip to be coated submersed in the electrolyte, with the strip being connected as a cathode, whereby cathode and anode are connected with the corresponding terminals of a DC power supply, characterized in that the bath with the electrolyte is delimited at the sides by a ring shaped, upright inner strip (15a) and outer strip (15) and from below by a base plate (16), that a middle strip (15b) is arranged between the inner strip (15a) and outer strip (15), that a vertical mast (22) is mounted on the base plate (16) at the common center point of the circle formed by the inner and outer strips, whereby the mast is electrically insulated with respect to the base plate, that arms (25) extend from the mast at a height which is greater than the width of the strips and extend into the space (21) of the bath, that two plane anodes (26a, 26b) possessing the form of a circle sector in their cross-sections and which can be rotated about the mast (22) by means of the arms (25) reach down into the bath from one arm (25) in each case almost to its bottom, whereby one anode (26a) is located in the area (21a) between the outer (15) and middle strips (15b) and the other anode (26b) is located in the area (21b) between the middle (15b) and inner strips (15a), and that the anodes (26a, 26b) are connected with the positive terminal of the DC power supply via the arms (25) and the mast (22) while the middle strip (15b) is connected with the negative terminal by the base plate (16).
11. Apparatus in accordance with one of Claims 7 to 10, characterized in that the strips (15, 15a) or (15b) stand in a ring seal (17) on the base plate (16).
12. Apparatus in accordance with Claim 11, characterized in that the ring seal (17) possesses a ring-shaped body (42) made of elastomer material whose surface possesses a ring-shaped groove (43), that a holder (44) consisting of two ring-shaped metal rails (45, 46) is inserted in this groove (43), whereby one metal groove (45) possesses a step (48) to accommodate the strip (15) in its top part and one possesses a groove (49) adjacent to this step (48).
13. Apparatus in accordance with Claim 12, characterized in that the strip (15) is pressed onto the wall (50) of the adjacent metal rail (46) by means of an O-ring in the groove (49) and the fluid pressure acting on this O-ring.
14. Apparatus in accordance with Claim 12, characterized in that the metal rails (45, 46) are made of iron.
15. Apparatus in accordance with Claim 12, characterized in that the ring-shaped body (48) is made of rubber.
16. Apparatus in accordance with Claim 12, characterized in that a connection is produced through the base plate (16), without an electrically conductive connection to the latter, and through the body (42) to the negative terminal of the power supply by means of a contact connector (63) with a pin ring (47).
17. Apparatus in accordance with at least one of Claims 7 to 16, characterized in that a tent (30) with an extraction device is stretched over all strips (15, 15a, 15b) from the mast (22).
18. Apparatus in accordance with at least one of Claims 7 to 17, characterized in that the outer strip (15) is clamped on the base plate (16) by means of rail-shaped clamping elements (20) acting on the outer side.
19. Apparatus in accordance with at least one of Claims 7 to 18, characterized in that the inner strip (15a) is clamped on the base plate (16) by means of rail-shaped clamping elements (20) acting on the inner side.
20. Apparatus in accordance with at least one of Claims 7 to 18, characterized in that the inner strip (15a) is kept in circular shape by means of tensioning elements (54) acting on the inner side and tensioning the strip outwards.
21. Apparatus in accordance with Claims 18 or 19, characterized in that the sleeves (27) are clamped on the surface of the strip by means of the rail-shaped clamping elements (20).
22. Apparatus in accordance with Claim 21, characterized in that the sleeves (27) are made of copper.
23. Apparatus in accordance with Claims 18 or 19, characterized in that contacting of the sleeves (27) with the negative terminal of the DC power supply is realized from below through the base plate (16) via the clamping elements (20) made of copper.
24. Apparatus in accordance with Claims 18 or 19, characterized in that contacting of the sleeves (27) with the negative terminal of the DC power supply is realized by a ring feeder (64) mounted on the base plate (16) via flexible cables (52) which can be plugged onto the sleeves.
25. Apparatus in accordance with at least one of Claims 7 to 24, characterized in that the anode consists of several closely adjacent rods (26) which are secured on the arms (25) of the mast (22).
26. Apparatus in accordance with at least one of Claims 7 to 25, characterized in that the mast (22) consists of a hollow square tube (56) on whose upper section a rotatable outer sleeve (24) is mounted which is electrically insulated with respect to the square tube and which supports the arms (25), and that a copper rod (32) inside the square tube connected both with the positive terminal of the power supply and also contacting the outer sleeve (24) passes through an opening in the base plate (16).
27. Apparatus in accordance with Claim 26, characterized in that the outer sleeve (24) is rotated by means of a motor (28) whose force is transferred to a gear wheel (55) mounted on the outer sleeve (24) by means of a chain (53).
28. Apparatus in accordance with Claim 26, characterized in that the outer sleeve (24) is rotated by means of a motor (28) whose force is transmitted to the outer sleeve (24) via a gear (29).
29. Apparatus in accordance with Claim 26, characterized in that the power supply from the copper rod (32) to the rotatable outer sleeve (24) is realized via a metallic liquid.
30. Apparatus in accordance with Claim 29, characterized in that mercury is used as the metallic liquid.
EP86102928A 1985-03-15 1986-03-05 Process and apparatus for electroplating strips Expired - Lifetime EP0194577B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86102928T ATE49242T1 (en) 1985-03-15 1986-03-05 METHOD AND DEVICE FOR THE GALVANIC COATING OF PRESS TAPE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3509388 1985-03-15
DE3509388A DE3509388C2 (en) 1985-03-15 1985-03-15 Method and device for the galvanic coating of press belts

Publications (3)

Publication Number Publication Date
EP0194577A2 EP0194577A2 (en) 1986-09-17
EP0194577A3 EP0194577A3 (en) 1987-10-14
EP0194577B1 true EP0194577B1 (en) 1990-01-03

Family

ID=6265351

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86102928A Expired - Lifetime EP0194577B1 (en) 1985-03-15 1986-03-05 Process and apparatus for electroplating strips

Country Status (7)

Country Link
US (2) US4640758A (en)
EP (1) EP0194577B1 (en)
JP (1) JPS61213392A (en)
CN (1) CN1011601B (en)
AT (1) ATE49242T1 (en)
DE (1) DE3509388C2 (en)
SU (1) SU1426459A3 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04234765A (en) * 1990-08-29 1992-08-24 Xerox Corp Base body, belt and electrostatic photographic image forming member, and these manufacture
US5064509A (en) * 1990-09-28 1991-11-12 Xerox Corporation Multilayer belts formed by electrodeposition
US5152723A (en) * 1990-12-24 1992-10-06 Xerox Corporation Endless metal belt assembly with hardened belt surfaces
CN100390326C (en) * 2004-01-06 2008-05-28 上海维安热电材料股份有限公司 Preparation method of composite cladding material and equipment
KR100686778B1 (en) * 2005-01-12 2007-02-23 엘에스전선 주식회사 Apparatus for manufacturing electrolytic metal foil
CN111575769B (en) * 2020-05-25 2021-05-14 太仓市华夏电镀有限公司 Automatic rack plating production line and rack plating copper-nickel-chromium production process

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3507770A (en) * 1967-12-08 1970-04-21 Charles G Fleming Apparatus for electrolytic refining of copper
US3772163A (en) * 1971-08-20 1973-11-13 J Jumer Electrochemical processing of inner surfaces of large vessels
US3783110A (en) * 1972-12-20 1974-01-01 Us Army Process for electrodeposition of metals under the influence of a centrifugal force field
DE2421296A1 (en) * 1974-05-02 1975-11-13 Held Kg Adolf METHOD AND DEVICE FOR MANUFACTURING CONTINUOUS LAMINATES
US4001094A (en) * 1974-09-19 1977-01-04 Jumer John F Method for incremental electro-processing of large areas
DE2950795C2 (en) * 1979-12-17 1982-07-29 Standex International Gmbh, 4150 Krefeld Method for producing an embossed engraving on a metallic endless belt connected by a weld seam

Also Published As

Publication number Publication date
CN86101406A (en) 1986-09-10
US4640758A (en) 1987-02-03
JPS61213392A (en) 1986-09-22
JPH0240753B2 (en) 1990-09-13
CN1011601B (en) 1991-02-13
ATE49242T1 (en) 1990-01-15
EP0194577A3 (en) 1987-10-14
SU1426459A3 (en) 1988-09-23
DE3509388A1 (en) 1986-09-18
EP0194577A2 (en) 1986-09-17
US4686016A (en) 1987-08-11
DE3509388C2 (en) 1993-12-09

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