US2739931A

US2739931A - Anodizing metal articles

Info

Publication number: US2739931A
Application number: US337393A
Authority: US
Inventors: Bernstiel Erwin
Original assignee: RHONDDA PLATING WORKS Ltd
Current assignee: RHONDDA PLATING WORKS Ltd
Priority date: 1952-02-26
Filing date: 1953-02-17
Publication date: 1956-03-27
Anticipated expiration: 1973-03-27
Also published as: BE517739A; NL176250B; FR1075365A; DE940862C; NL83851C; GB728747A; CH313180A

Description

March 27, 1956 E. BERNSTIEL ANODIZING METAL ARTICLES 2 Sheets-Sheet 1 Filed Feb. 17, 1953 Inventor m jERA s T/EL A ttorney March 27, 1956 BERNSTIEL ANODIZING METAL ARTICLES 2 Sheets-Sheet 2 Filed Feb. 17, 1953 Inventor Erwin 36k: TIE!- A ttorney 2,739,931 ANODIZING METAL ARTICLES Erwin Bernstiel, Cardiff, Wales, assignor to Rhondda Plating Works Limited, Dinas, Rhondda, Glamorgan,

Great Britain, a British company Application February 17, 1953, Serial No. 337,393 Claims priority, application Great Britain February 26, 1952 17 (Zlaims. (Cl. 204-23) The present invention relates to methods of and means T fOI anodizing metal articles, for example fastener ele- .ments of slide fasteners, made of a suitable metal or :metal alloy, such as aluminium or aluminium alloy. The term metal article as hereinafter used shall mean an :article which is, at least in part, made of an anodizable .metal, and similarly the term fastener elements shall :mean such elements made of an anodizable metal.

It is known to anodize fastener elements of slide fastenersafter the fastener elements have been attached to a carrier tape which comprises an electrically conducting wire at its edge carrying the fastener elements so that the .fastener elements contact the wire and are, thus, electrically interconnected by the wire.

In modern mass production of slide fasteners, the fastener elements are usually attached to carrier tapes of a considerable arbitrary length and spaced along the tape in groups separated one from the next by a length of the tape free from fastener elements, the fastener elements of corresponding groups of two such tapes being interlocked with each other, the tapes being subsequently cut about half way between adjacent groups of fastener elements whereby to obtain pairs of interlocked slide fastener stringers which are finally provided with a slider and-with end members to constitute a complete slide fastener. To anodize the fastener elements it is desirable to effect the anodizing, while the fastener elements of the two tapes are interlocked with each other and before the tapes are cut, by passing the tapes through a suitable anodic bath of an electrolytic cell.

However, various difficulties have been experienced.

The wire at the edge of each tape has to be thin so as not unduly to decrease the flexibility of the slide fastener. Such a thin Wire cannot reliably carry a heavy electric current and, more specifically, cannot reliably carry the current across aggregate lengths of thetapes free from fastener elements between successive groups thereof which may be immersed simultaneously in the electrolytic bath at a given moment. Moreover, the oxide layer formed on the fastener elements during anodizing is a bad electric conductor, which renders it impossible or at least difficult, after the oxidization of the surfaces of the slide fastener elements has been initiated, to establish reliable electric contacts between a current feeding element and travelling slide fastener elements. To obviate this drawback, it has already been suggested to fix fastener stringers directly to the electric supply source at a plurality of fastener elements before the oxidization commences; this, however, necessitates jigging which increases the manufacturing costs and impedes continuous anodizing of slide fastener elements attached to carrier tapes of consider- .able arbitrary length.

If a plurality of metal articles, which are large as coinpared with a slide fastener element, are to be anodized, it may be easier to fix the individual articles to the electric supply source, but the disadvantage still exists that the oxide layer formed on such an article during anodizing is liable to impair the conduction of electric current between. a current feeding element and the articles, if the current feeding element is not fixed to the articles, while if the current feeding element is fixed to the articles a conimpeded.

2,739,931 Patented Mar. 271, 1956 It is an object of this invention to provide an improved method of and means for anodizing metal articles.

It is a more specific object of the invention to provide an improved method of and means for anodizing fastener elements of slide fasteners.-

It is another object of the invention to provide an improved method of and means for anodizing fastener elements on slide fastener tapes of considerable arbitrary lengths.

It is a further object of the invention to provide an improved method of and means for anodizing interlocked fastener elements of pairs of slide fastener tapes of considerable arbitrary lengths.

It is a more specific object of the invention, when anodizing metal articles, to overcome difficulties resulting from the poor electricconductivity of the oxide layers formed on such articles.

it is still another object of the invention to provide means for anodizing fastener elements on slide fastener tapes of considerable artitrary lengths while the tapes continuously travel from an input side to an output side of an anodic bath.

It is still a further object of the invention to provide means for gradually increasing the intensity of the electric current flowing through each fastener element on a slide fastener tape While the tape continuously travels from an input side to an output side of an anodic bath.

It is yet another object of the invention to provide methods of and means for reliably anodizing fastener elements of slide fastener tapes without the necessity of jigging the elements to an electric supply source.

These and other objects and advantages of the inventionwill become apparent to those skilled in the art from the following detailed description of the invention when read with reference to the accompanying drawings, in which:

Fig. l somewhat diagrammatically illustrates a portion of two tapes to which slide fastener elements are attached;

Fig. 2 is a section through a tape of Fig. 1;

Fig. 3 is a general perspective view of an arrangement of the invention, some parts being broken away;

Fig. 4 is a perspective View of a part of the arrangement of Fig. 3 on a larger scale;

Fig. 5 is a section along the line V-V of Fig. 4;

Fig. 6 illustrates a modification of a detail of Fig. 5; and

Fig. 7 illustrates another modification of the detail of Fig. 5.

The invention consists broadly in a method of anodizing a metal article, comprising the steps of immersing the article or a part thereof in a suitable anodic bath of an electrolytic cell, anodizing the article or its part while immersed in the anodic bath, scraping the oxide layer formed on thearticle from a portion thereof whereby to provide a sufficiently good electric conduction through such portion, and feeding an electric current to the article through the scraped portion thereof.

electrically interconnected slide fastener elements attached to a carrier tape, comprising the steps of immersing adjacent fastener elements of the tape in a suitable anodic bath of an electrolytic cell, anodizing the adjacent fastener elements, scraping the'oxide layer formed on said fastener elements from portions thereof, and feeding an electric current through the scraped portions thereof. Preferably, the oxide layer is scraped from fastener element portions which lie at one and the same side of the tape, while the oxide layer of fastener element portions lying at the other side of the tape is not substantially interfered with.

The invention also consists in a method of anodizing electrically interconnected fastener elements attached to a carrier tape, comprising the steps ofimmersing the tape or 'a' section thereof in a suitable anodic bathof an electroly-tic cell to anodize fastener elements of the tape or of the said tape section, removing the tape or the tape section from the anodic bath, scraping the oxide layer formed-on the fastener elements while the 'tape or'the tape section wasim'mersed in the anodic bath from fastener element portions lying at one side of the tape, immersing the tape or the tape section again'in the anodic bath to continue the anodizingof the fastenerelements, removing the-tape or the tape section again from the anodic bath, scraping the oxide layer formed on the fastener elements while the tape or the tape section was immersed in the anodic bath from the fastener element portions lying at the sameone side of the tape as before, and, if necessary, continuing this process until an oxide layer of sufiicient thickness has beenformed onthe fas tener element portions'lying'at the other side of the tape.

Preferably, fastener elements of two tapes are interlocked with each other before the tapes or sections thereof are immersed in the anodic bath, whereby to 'treat the fastener element of the twotapes or the sections thereof simultaneously.

In any case, after the termination of the scraping process, or of the last scraping process, the anodizing process may be continued, whereby superficially to anodize the previously scraped portion or portions.

It will be recognized that, by repeatedly scraping the oxide layer from one and the samefastener element'portions, the oxide layer may be wholly or in part broken and/ or removed from the said-portions lying at one side of the tape which therefore afford a good electric conduction through such portions of fastener elements and enable gradually to buildup a substantially uniform oxide layer on the fastener element portions lying at the other side of the tape, which advantageously forms the visible front of the completed slide fastener, While the said one side of the tape forms the rear of the slide fastener and is, thus, inmost cases not visible in use. Moreover, experience has shown that in many cases, particularlyif the anodizing process is continued after the scraping process has been terminated, the effect of the scraping is not, or is hardly, visible to the naked eye.

The invention also consists in an arrangement for performing the methods hereinbefore described, comprising means for feeding a carrier tape to which slide fastener elements are attached in a zig zag path through an electrolytic cell, and means for scraping fastener element portions lying atone side of the'tape. The feeding means may be arranged relatively to the electrolytic cell in such a manner that each'part of the tape while travelling along the zigzag path is alternately immersed in an anodic bath of the electrolytic cell and removed therefrom, the scrap ing means being arranged for scraping fastener element portions while the tape part carrying the fastener ele ments which are being scraped is removed from the anodic bath.

The scraping means may be rotatable brushes, for example Wire brushes, or knurled rollers.

Referring now to the drawings, Figs. 1 and 2 illustrate portions of tapes 1 having thickened edges 2 to which slide fastener elements 3 are attached. The tapes 1 are of a considerable arbitrary length, and the fastener elements 3 are spaced along the tapes 1 in groups separated one from the next by tape lengths a free from fastener elements 3. Each thickened tape edge 2 comprises a plurality of metal wires 4 which are so arranged that the fastener elements 3 make mechanical and electric contact With'the metal wires 4 whereby the fastener elements 3 are electrically interconnected with one another. For cl-aritys sake, the Wires 4 are illustrated as simply placed on top of the thickened edge 2 and held in position'by the fastener elements 3 when clamped on to the tape edges. ln 'actual practice however, the wires are preferably connected to the tape edges 2 in any suitable manner.

The arrangement illustrated in Figs. 3 to 5 serves for anodizing the fastener elements 3 of the tapes 1. The arrangement comprises an electrolytic cell formed by a metal tank 10 containing, in'use, a suitable anodic bath 11. A plurality of metallic guide rollers 12 are rota-tably mounted in

brackets

13 and 14 of insulating material. The ends of the guide rollers 12 protrude beyond the bracket 14. Gear wheels 15 are keyed to the protruding ends of the guide rollers 12, one to each. Eachpair of adjacent gear wheels '15 mesh with an idling gear Wheel 16. Furthermore, each gear Wheel 15 (except the first gear Wheel 15 nearest the input side of the anodic bath at the extreme lefthand side of Fig. 3) meshes with a pinion 17 of smaller diameter, the pinions'17 being keyed to ends, protruding beyond the bracket 14, of rollers 20 rotatably mounted in the

brackets

13 and 14, one pinion 17 being keyed to each roller 20. Each roller '20'has five guide grooves, the bottoms of the guide grooves being knurled as indicated in Fig. 4 at 20a, the grooves being laterally defined by six raised portions 20b of each knurled roller 20. The Width of'one of the guide grooves formed between adjacentraised portions 20]) corresponds substantially-to the width of a pair of tapes 1 carrying interlocked fastener elements 3. An electric motor 21 drives the last guide roller '12 nearest the output side of the 'ano dic bath (the extreme guide roller at the righthand side of Fig. 3) by means of a pulley 22, a pulley 23 and a belt 24, the pulley 22 being fixed to the rotor of the electric motor '21,and the pulley 23 to the said last guide roller '12. A wringer 25 is arranged at the output side of the anodic 'bath and is driven by the electric motor 21 by means of the pulley 20, a pulley 26 keyed to one of the press rollers of the wringer 25 and abelt 27. In frames 30, guides 31 are mounted which are illustrated as rotatable idling rollers. Each metallic guide roller 12 is provided with a slip ring 32 electrically connected in any known manner to the positive terminal of an electric supply source, the negative terminal of which is connected at 33 to themetal tank 10 acting as the cathode-of the electrolytic cell.

Electric resistors

34, 35, 36 are inserted in the electric connections between the first three rollers 1'2 adjacent the input side of the anodic bath and the positive terminal of the electric supply source. The resistance of the resistor 34 is higher than that'of the-resistor 35, which in'turn is higher than that of the resistor 3 6.

The arrangement operates as follows:

Five pairs of tapes 1 with their fastener-elements 3 interlocked are. passed substantially parallel to each other in a zig-zag path around the first guide roller 12 at the input side of, and arranged above,-the anodic bath 11, then down'and around the first guide 31 (counted from the left-hand side of Fig. 1) within the anodic bath 11, up and along'one of the guide channels of the first knurled roller'20 above the anodic bath, around the second'guide roller 12, down and around the second guide 31 within the anodic bath, up and along the corresponding guide groove-of the second knurled roller 20, around the third guide roller .12, and so on,-until the last guide roller 12 has been reached, whereupon the tapes are threaded through the wringer 25. A suitable electric potential is now applied to the electrolytic cell, and the electric motor 21 is started. An electric current flows from the positive potential of the supply source through all theguide rollers 12 to thefastener elements of the tapes into the anodic bath and back to the negative terminal of the electric supply source. The electric motor 21 drives the wringer25 and the last guide roller 12 adjacent the output side of theanodicbath. The gear wheel 15 keyed to the said last guide roller 12 drives the idling gear wheel 16 'meshingwith it, the idling gear wheel 16 driving in turn the next gear wheel 15'and so on, whereby all the guide rollers 12 are'driven in the same sense as indicated by the inscribed arrows, the

gear wheels

15 and 16 being so dimensioned that all the guide rollers 12 rotate with a substantially equal speed. Each gear wheel 15 (except the first gear wheel at the input side of the anodic bath) drives one of the pinions 17 keyed to the knurled rollers 20. As can be seen from Fig. 4, the knurled rollers 20 rotate in a sense opposite to the sense of rotation of the guide rollers 12. Since the diameter of each pinion is smaller than that of the gear wheels 15, the knurled rollers 20 rotate with a higher speed than the guide rollers 12. The rotation of the guide rollers 12 and the press rollers of the wringer causes the tapes 1 to travel through the anodic bath in a zig-zag path from its input side to its output side in the direction of the arrow A in Fig. 1.

It will easily be seen that by such an arrangement when using a suitable speed of travel for the tapes 1 and fastener elements 3 attached thereto it may be achieved that the fastener elements 3 are immersed in the anodic bath for short successive periods during each of which only a thin oxide layer is formed which can easily be removed by the knurled rollers 20 scraping the adjacent sides of the fastener elements 3, while owing to the repeated immersions the surfaces of the fastener elements which are not scraped by the knurled rollers 20 and which do not contact the guide rollers 12 are provided with a uniform, sufiiciently thick, oxide layer when thefastener elements 3 emerge from the anodic bath at its output side. Moreover, if many, for example twelve, guide rollers 12 are provided outside the electrolytic bath 11, the length of the tapes 1 between successive guide rollers 12 may be kept short, whereby the requirements on the contacts between interlocked fastener elements 3 may be reduced.

It is known that it is advantageous to increase gradually the current through a metal article while anodizing it. Now, the

resistors

34, and 36 enable the electric current flowing from the respective guide rollers 12 into the contacting fastener elements 3 to be kept smaller than the corresponding currents flowing into contacting fastener elements 3 from guide rollers 12 not associated with such resistors. The different resistances of the said resistors cause the current through a certain fastener element 3 to increase gradually while the fastener element travels through the electrolytic bath 11, until a high current intensity is reached when the said fastener element contacts the fourth and followingguide rollers 12.

It will also be appreciated that it is no longer necessary for the wires 4 to carry an anodizing current through the entire length of the tape portions immersed at any instant of time in the anodic bath. With the arrangement described it is only required that the wires 4 carry the current through the comparatively small length of the tape portions between adjacent guide rollers 12 since at each such guide roller 12 an electric connection with the supply source is established or re-established, while after the first guide roller 12 has been passed by a fastener element 3, the oxide layer on the fastener element 3 is scraped by. the knurled rollers 21} immediately before the said element reaches one of the subsequent guide rollers 12. From the drawings it will also be recognized that the knurled rollers 29 act all on one and the same sides of the fastener elements.

It is somewhat difficult in practice to ascertain with certainty. whether the knurled rollers 20 in fact remove the oxide layer or only break it up. Whatever, from a scientific point of view, the true explanation may be, it has been found that with the specific embodiment described having twelve guide rollers outside the anodic bath, twelve further guides in the anodic bath and knurled rollers rotated at a high speed, the guide rollers being electrically connected to a terminal of the electric supply source, a satisfactory anodizing was obtained of the surfaces, remote from the guide rollers, of the fastener elements 3 carried on the tapes 1 having wires 4 at their thickened edges 2 in contact with the fastener elements. The wringer 25 serves in known manner to remove liquid electrolyte from the tapes which may subsequently be 6 washed and dyed together with the anodized fastener elements in known manner.

Many modifications are possible. For example, less or more than five pairs of tapes may be treated simultaneously. ments of which are interlocked, single tapes may betreated. If pairs of tapes with interlocked fastener elernentsare' treated, then in some cases the electric direct connection between one fastener element of one tape and an adjacent interlocked fastener element of the other tape may be sufiicient for allowing the electric anodizing current to flow, in which case the wires 4 may be dispensed with or may be only provided for bridging the tape lengths a between adjacent; groups of fastener elements 3. The direct current electric supply source may be replaced by an alternating electric current supply source, in which case the

resistors

34, 35, 36 may be replaced by electric impedances such as choke coils.

In Fig. 6, reference numeral indicates a knurled roller similar to the knurled roller 20. However, the knurled roller 121) is so arranged that it not only scrapes fastener elements of the tape 1 but also scrapes the periphery of the adjacent guide roller 12 to keep the same clean. Moreover, an idling counter-roller 37, which preferably is made of an elastic material, presses the tapes 1 firmly against the respective guide roller 12 whereby to improve the electric contact between the guide roller 12 and the fastener elements of the tapes 1.

In the further modification of Fig. 7, the knurled roller is replaced by a rotating brush 220, which may be a wire brush, for scraping the fastener elements of the tapes 1 and also for cleaning the respective guide roller 12.

Other modifications are possible. For example, less or more than twelve guide rollers 12 and a corresponding number of knurled rollers 20 and guides 31 may be provided. The knurled rollers 20 need not be metallic rollers.

It should be clearly understood that the embodiments illustrated are given by way of example. Many further modifications, additions and omissions may be effected Without departing from the scope and spirit of the invention.

.I claim:

1. An arrangement for anodizing electrically interconnected fastener elements attached to a carrier tape, com-- prising an electrolytic cell for receiving an anodic bath, the electrolytic cell having an input side and an output side, a rotatable guide roller arranged near the output side of the electrolytic cell, a plurality of further rotatable guide rollers arranged between the said first mentioned guide roller and the input side of the electrolytic cell, a plurality of guides, the said guides and guide rollers being staggered relatively to one another, a drive for rotating at least the said guide roller at the output side of the electrolytic cell so that the tape when trained around the said guide rollers and the said guides is drawn by the driven guide roller to travel around the said guide rollers and the said guides along a substantial zig-zag path from the input side to the output side of the electrolytic cell, and means for scraping fastener element portions lying at one side of the travelling tape.

2. An arrangement as claimed in claim 1, wherein the guide rollers are arranged to lie out-side the anodic bath of the electrolytic cell and the guides are arranged to lie inside the said anodic bath so that the tape when travelling along the zig-zag path is in part immersed in, and in part removed from, the anodic bath.

3. An arrangement as claimed in claim 1, wherein gear means are provided between adjacent guide rollers, whereby positively to rotate all the guide rollers for drawing the tape or tapes through the anodic bath.

4. An arrangement as claimed in claim 1, wherein mean-s are provided for rotating the scraping means in the sense opposed to the direction of travel of the fastener elements.

Instead of treating pairs of tapes the fastener ele-' 5. -'An'arrangement as claimed in claim 1,- wherein the guide rollers outside the anodic bath are metal rollers, means being providedfor electrically connecting the metal rollers 'to a terminal of an electric supply source, and further means being provided for electrically connecting theother terminal of the supply source to the anodic bath when in the electrolytic cell, whereby the fastener elements while in mechanical contact with the said guide rollers are connected through the same to the said first terminal of the electric supply source. I V p 6. An arrangement as claimed in claim 5, wherein the means for electrically connecting at least one of the metal rollers to the terminal of the electric supply source comprises an electric impedance for reducing the electric current flowing through the said connecting means.

7. An arrangement as claimed in claim 5, wherein means are Provided for acting on the circumferences of the second and following guide rollers (counted from the input side of the electrolytic cell) for cleaning the said circumferences while in use. I

8. An arrangement as claimed in claim 5, wherein a counter-roller is provided for pressing the tape while travelling around one of the guide rollers firmly against the same.

9. A method of anodizing fastener elements which are electrically interconnected and are attached to a fastener tape, comprising the steps of continuously drawing at least a section of the said tape over a first electric contact element in such a manner that the said first contact element successively makes electric contact with each of the fastener elements, to feed an electric current to the interconnected fastener elements, passing the tape section into an anodic bath to anodize fastener elements of the said tape section, removing the tape section from the anodic bath, scraping the oxide layer formed on a part, lying at one side only of the tape, of each fastener element whereby substantially to restore the electric conductivity of the said parts, drawing the tape section over a second electric contact element in such a manner that the said second contact element successively makes electric contact with the scraped parts of the fastener elements to continue the feed of the electric current to the interconnected fastener elements, passing the tape section of cyclically removing the tape section'frorn the anodic bath,' scraping the oxide layer formed on the said parts, passing the tape section over an anode contact element and passing the tape section into the anodic bath until an oxide layer of sufficicnt thick'ness'has been built up on the remainder of each fastener element of the tape section.

10. A method as claimed in claim 9, wherein fastener elements of two tapes are interlocked with each other before the tape sections are first immersed in the anodic bath, whereby to treat the fastener elements of the two tape sections simultaneously. M

ll. A'method as claimed in claim 9, wherein after the termination of the last scraping process, the anodizing process is continued, whereby superficially to anodize the previously scraped portions.

12. A method of anodizing metal articles which. are electrically interconnected and attached to a flexible carrier, comprising the steps of continuously drawing the articles into and through an anodic bath, drawing the articles over a plurality of spaced electric contact elements in such a manner that each contact element successively makes electric contact with the same part of each article, passing an electric current from a first of the said contact elements through a contacting article to other articles and thence through the anodic bath to a cathode thereby frorning oxide layers on at least some of the articles, in the bath, scraping the oxide layer formed on the said article parts whereby to improve the electric conductivity of the said article parts, passing an electric current from 8 a second of the said contact elements through a scraped contactingjarticle part to other articles and'thence through the anodic bathto the said cathode thereby forming an oxide layer on each of the said articles in the bath, scraping the oxide layer formed at thesaid article parts, and

cyclically repeating the steps of passing an electric current, formin'g an oxide layer on articles in the bath, and scraping the oxide layer formed at the: said article part, until an oxide coating of a desired thickness has been built up on the remainder of each article.

13 A method of anodizing fastener elements which are electrically interconnected and attached to, a fastener tape, comprising the steps of continuously drawing the tape into and through an anodicbath across a plurality of spaced contact elements in such a manner that each contact element successively makes electric contact with a part, lying at one side only of the tape, of each of the said fastener elements, passing an electric current from a first of the said contact elements throughacontacting fastener element to other fastener elements and thence through the anodic bath to a cathode thereby forming an oxide layer on fastener elements, in the bath, scraping the oxide layerformed on the said parts of the fastener elements in the bath whereby to improve the electric con ductivity of the said parts, passing an electric current from a second of the said contact elements through the scraped parts of a contacting fastener element to other fastener elements and thence through the anodic bath to the cathode thereby forming an oxide layer on each of the said fastener elements in the bath, scraping the oxide layer formed at the said part of each fastener element, and cyclically repeating the steps of passing an electric current, forming oxide layers on fastener elements in the bath, and scraping the said part of each fastener element, until an oxide coating of a desired thickness has been built up on the remaining part of each fastener element.

14. An arrangement for anodizing fastener elements which are electrically interconnected and attached to a carrier tape, comprising an electrolytic cell for receiving an anodic bath and having an input and output side, a first electric contact element, a first combination of an electric contact element and a scraping means spaced from the said first electric contact element, and atleast one further combination of an electric contact element and a scrapingmeans spaced from the immediately preceding combination, and means for continuously drawing the carrier tape through. theelectrolyticv cell along an open path from the said input side to the said output side in such a manner that during movement of the can rier tape each fastener elementsuccessively contacts, the, first electric contactelement and during movement of the carrier tape between the input and output side of the electrolytic cell a part lying at one side only ofthecarrier tape of each of the said fastener elements successively contacts the scraping means andimmediately there afterthe electric contact element of each combination, so that the scraping means scrape the said element part and the electric contact element contacts the scraped element part.

15. An arrangement as claimed inclaim 14, wherein the scraping means are rotatable brushes. 1 16. An arrangement as claimed in claim 15, wherein the rotatable brushes are wire brushes.

17, An arrangement as claimed in claim 14, wherein the scraping means are knurled rollers.

References Cited in the file of this patent UNITED STATES PATENTS 93 8,451 Aylsworth Oct. 26,

Claims

1. AN ARRANGEMENT FOR ANODIZING ELECTRICALLY INTERCONNECTED FASTENER ELEMENTS ATTACHED TO A CARRIER TAPE, COMPRISING AN ELECTROLYTIC CELL FOR RECEIVING AN ANODIC BATH THE ELECTROLYTIC CELL HAVING AN INPUT SIDE AND AN OUTPUT SIDE, A ROTATABLE GUIDE ROLLER ARRANGED NEAR THE OUTPUT SIDE OF THE ELECTROLYTIC CELL, A PLURALITY OF FURTHER ROTATABLE GUIDE ROLLERS ARRANGED BETWEEN THE SAID FIRST MENTIONED GUIDE ROLLER AND THE INPUT SIDE OF THE ELECTROLYTIC CELL, A PLURALITY OF GUIDES, THE SAID GUIDES AND GUIDE ROLLERS BEING STAGGERED RELATIVELY TO ONE ANOTHER, A DRIVE FOR ROTAT-