US 3282819 A
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Description (OCR text may contain errors)
Nov. 1, 1966 Filed Dec. 5, 1962 Fla 1 1.. B. HOVANIC 3,282,819
TREATING OF WORKPIECES 4 Sheets-Sheet 1 INVENTOR. LEONARD B. HovANlo Nov. 1, 1966 B. HOVANIC 3,282,819
TREATING OF WORKPIECES Filed Dec. 5, 1962 4 Sheets-Sheet 5 INVENTOR. LEONARD B HOVAN 1c Q/MW Nov. 1, 1966 L. B. HOVANIC 3,282,819
TREATING OF WORKPIECES Filed Dec. 5, 1962 4 Sheets-Sheet 4 e 8 Hll INVENTOR A DUE/v.96
LEONARD B. HOVAN 1c,
United States Patent 3,282,819 TREATWG 0F WORKPIECES Leonard B. Hovanic, 17 46 Oak St. SW., Warren, Ohio Filed Dec. 5, 1962, Ser. No. 242,419 4 Claims. (Cl. 204-2111) The present invention relates to the treating of workpieces, more particularly to apparatus for plating workpieces, and the principal object of the invention is to provide new and improved apparatus and methods of the character described.
Heretofore, the plating of small workpieces in large quantities has required the use of expensive, complicated apparatus which requires considerable attention and maintenance. By its Very nature, such apparatus is rather ill-suited to continuous, high-speed production. The present invention, however, introduces several new concepts to the quantity plating of small workpieces and provides relatively simple, trouble-free apparatus specifically aimed at continuous, high-speed production. Other advantages will readily become apparent from a study of the following description and from the drawings appended hereto.
In the drawings accompanying this specification and forming a part of this application there is shown, for purposes of illustration, an embodiment which the invention may assume, and in these drawings:
FIGURE 1 is a side elevational view of apparatus embodying the present invention,
FIGURE 2 is an end elevational view generally corresponding to the line 2-2 of FIGURE 1,
FIGURE 3 is an enlarged view in longitudinal section generally corresponding to the line 3-3 of FIGURE 2,
FIGURE 4 is a transverse sectional view generally corresponding to the line 4-4 of FIGURE 3,
FIGURE 5 is a transverse sectional view generally corresponding to the line 5-5 of FIGURE 1,
FIGURE 6 is an enlarged perspective view of a detail,
FIGURE 7 is a fragmentary diagrammatic view, and
FIGURE 8 is a view similar to FIGURE 1 but of a different embodiment.
With reference to FIGURES l and 4, there is illustrated a drum 10 having an intermediate portion 11 and reduced diameter end portions 12 and 13 joined to the intermediate portion 11 by respective conical portions 14, 15. For reasons to appear, the drum end portions 12, 13 carry respective ring members 16.
As herein illustrated, the lower portion of drum 10 is immersed in a tank 17 containing a suitable plating solution 18 and is rotatable therein about its axis on fianged pairs of rollers 19 (see also FIGURE 5) rotatably mounted on the tank for engagement with respective ring members 16. Means are provided for effecting rotation of the rollers 19 at the right-hand end of the drum, in the position of parts viewed in FIGURE 1, and each of such rollers provides a pulley like portion cooperable with a suitable drive belt 20. An idler pulley 21 ensures sufiicient wrap of the belt about the pulley portions of rollers 19 and keeps the belt from contacting drum end portion 12. A motor 22 is engaged with the belt to effect rotation of rollers 19 and consequent rotation of drum 10. At the opposite, or left-hand end of the drum, the motor, idler pulley and belt are preferably omitted, only the pair of flanged rollers being used.
Turning for a moment to the more specific construction of drum 1t) and with reference to FIGURES 1 through 4, drum 10 is preferably formed of a plurality of alternate segments 2324 which may be secured together in any suitable manner to form the drum. With particular reference to FIGURE 6, each segment 23 has an intermediate portion 123 which in part forms the intermediate drum portion 11, angled portions 223, 323 which in part form respective conical drum portions 14, 15 and end portions 423, 523 which in part form respective reduced diameter drum end portions 12, 13. For a purpose to appear, each segment 23 is formed of an electrically conductive material such as a suitable metal and, since the drum diameter varies, the width of each segment 23 in part forming the drum also varies in direct proportion therewith. As will be evident, segment portion 123 is of constant width, portions 223 and 323 progressively narrow in width from their ends adjacent portion 123 to their ends adjacent respective portions 423, 523, while the latter segment portions are a constant width which is narrower than that of portion 123.
Since the segments 23 are adapted to carry electrical current as will later be disclosed, it is desirable that they have a relatively constant cross-sectional area for relatively constant current-carrying capacity. To this end, the narrowed portions of the segments are proportionately thickened, as shown, to provide such constant, crosssectional area.
With reference to the position of parts seen in FIGURE 6 and for a purpose to appear, certain of the upper, or drum-interior forming surfaces of the segments 23 and certain of the lower, or drum-exterior forming surfaces of such segments are covered with a dielectric coating. More specifically, the upper surfaces of each segment portion 423, 523, the lower surface of each segment portion 123, and both the upper and lower surfaces of each segment portion 223, 323 are so covered.-
Drum segments 24, while preferably identical in shape and size to drum segments 23, are formed of a suitable dielectric material so as to electrically insulated adjoining drum segments 23. Also, drum egments 24 are preferably porous so that the tank solution 18 has ready access to the drum interior. Alternatively, or cumulatively, segments 23 may be rendered porous for the same purpose as segments 24, such porosity conveniently being effectuated by providing such members with a plurality of relatively small, through apertures.
As best seen in FIGURES 3 and 4, a helical fin 25 is secured within the drum 10 and extends from end-toend thereof. Such fin may be formed of any suitable material having the necessary strength and wear-resistance; however, if such fin is an electrical conductor, it must be suitably insulated from the drum. segments 23 to insure against establishing an electrical connection t'herebetween. In the present embodiment and with the indicated direction of drum rotation, fin 25 is of lefthand configuration for reasons to become clear.
With reference to FIGURES 1 and 2, a brush holder stand 26 is disposed at each end of the drum 10 and since such stands are preferably identical, only one need be described in detail. As seen in FIGURE 2, the stand 26 at drum end 12 supports two sets of brushes 27, 28 for sliding engagement with the exterior of the dnum end 12. Brush sets 27, 28 are disposed in spaced relation on opposite sides of the drum axis, each engaging a lower portion of the drum end 12 so as to pass current only to those drum segments 23 which are immersed in the tank solution 18. As herein shown, each brush set comprises three individual brushes for respectively engaging three adjoining drum segment 23; however, it is to be understood that a greater or lesser number of brushes may be employed in either or both of said brush sets. As seen in FIGURES 3 and 4, a plurality of anode members 29 are immersed in the tank solution 18, such members being chosen for the desired type of plating to be accomplished.
Completing the present structure and with reference to FIGURES 1 and 3, a conveyor or the like 30 is designed to carry workpieces to be plated in the direction Patented Nov. 1, 1966' of the arrow for discharge into drum end 12. Similarly, a conveyor 31 is designed to receive workpieces discharged from drum end 13 and to carry them in the direction of the arrow for further processing or the like.
With the drum rotating in the direction indicated in the various views, with the workpieces to be plated being discharged continuously into drum end 12 by conveyor 30 and with both brush sets 27 connected to the negative side of an electrical plating circuit (FIGURE 7) and with both brush sets 28 and the anodes 29 connected to the positive side of such circuit, operation will be as follows:
As the workpieces are advanced from right to left (FIGURES 1 and 3) within the rotating drum 10 by virtue of the helical fin 25, they will'come into electrical contact with certain drum segments 23 when they arrive at the drum intermediate portion 11 after passing beyond the drum end 12 and the conical drum portion 14, it being recalled that the portions of the drum segments 23 in part forming the drum end 12 and the conical drum portion 15 have their drum-interior surfaces covered with a suitable insulating material. 1
Turning now to FIGURE 4, the workpieces in the intermediate drum portion will tend to lie along that portion of the interior wall of the rotating drum indicated by the bracket. Now, since the drum segments 23 at such drum portion are connected to the negative branch of the plating circuit by means of the brushes of brush set 27 as before described, and since the workpieces are in contact with such drum segments 23 at this time, they 'will also be connected to the negative plating circuit branch and thus function [as cathodes and accumulate plating thereon. As the drum rotates, the workpieces will be advanced longitudinally of the drum by the fin 25, the workpieces sliding and tumbling along the drum interior as they are advanced longitudinally thereof but nevertheless remaining in the bracketed portion of the drum and thus continuing to accummullate plating.
When the workpieces arrive at the conical drum portion 15, plating thereof will cease since they are nowremoved from the electrical plating circuit, it being recalled that the drum segments 23 in part forming the conical drum portion 15 and the drum end 13 have their drum-interior surfaces coated with the previously mentioned insulating material. Pin 25 will continue to advance the workpieces through the drum portion 15, out of the plating solution 18 and through thedrum end 13 and will discharge such pieces on to the conveyor 31 which will carry them on for further processing or the like.
As will be evident, the foregoing plating operation will be continuous, the workpieces being carried in a steady stream to the drum 10 by the conveyor 30' and discharged in a steady stream from the drum on to the conveyor 31.
An important feature of the present invention is the provision of means to prevent the buildup of plating deposits on the drum segments 23. Referring to FIG- URES 4 and 7, it will be understood that during the time such segments are in contact with the brushes of brush sets 27, the exposed faces of such segments immersed in the solution 18 will unavoidably be plated along with the workpieces since they also function as cathodes; however, as the rotating drum carries the drum segments 23 around into contact with brushes of brush sets 28 which are connected to the positive plating circuit branch, such segments will now commence functioning as anodes, the previously deposited plating thereon being removed and passing into the plating solution. Accordingly, no appreciable plating build-up on the drum segments 23 can occur and thus periodic removal of such plating build-up is obviated.
While the apparatus hereinabove described has been disclosed as used for plating, it is to be understood that it may also be used for electro-cleaning workpieces merely by changing current flow through the brush sets 27, 28 and by using a different solution within the tank as will be understood by those skilled in the art. Moreover, as seen in FIGURE 8 wherein similar parts are identified by the same reference characters as before but with the suflix a added, the drum may be modified to permit the use of an electro-cleaning process which is highly effective under certain circumstances. In this embodiment, drum segments 23a are not a continuous electrical conductor from end-to-end of the drum as hereinbefore described but each is divided into a pair of segment portions, electrically insulated from each other by an insulating band 32 or the like, one of which is disposed at the right end of the drum and the other of which is disposed at the leftend of the drum. With the segments 23a thus electrically separated, alternating current may be fed to the right-hand end of the rotating drum to effect initial cleaning of the workpieces being advanced therethrou-gh while direct current may be fed to the left-hand end of the drum to effect final cleaning of the workpieces just prior to their discharge from the drum.
Obviously, the drum seen in FIGURE 8 is not limited to the feeding of alternating current to the rightahand end and the feeding of direct current to the left-hand end. Neither is the drum limited to use for electro-cleaning since it may in some plating operations be desirable to effectuate a change in the plating circuit, either in the magnitude of current flow or in its direction, during advancement of the work-pieces from end of the drum to the other.
In view of the foregoing, it will be apparent to those skilled in the art that I have accomplished at least the principal object of my invention and it will also be apparent to those skilled in the art that the embodiments herein described may be variously changed and modified, without departing from the spirit of the invention, and that the invention is capable of uses and had advantages not herein specifically described; hence it will be appreciated that the herein disclosed embodiments are illustrative only, and that my invention is not limited thereto.
1. Apparatus for continuously plating workpieces, comprising a tank for containing a plating solution, a drum rotatable about a generally horizontal axis and open at both ends for respectively receiving and discharging workpieces, said drum having a main section positioned for rotation in the plating solution, a reduced diameter end section above the plating solution, and a plurality of longitudinally extending, current-conductive members electrically insulated from each other and arranged about the drum axis and in part forming the inner periphery of said drum, said drum being pervious to provide for free flow of the plating solution thereinto and said members spanning said main drum section and extending into said drum end section, each member being greater in width at said drum main section than at said drum end section and greater in thickness at said drum end section than at said drum main section to provide a cross-sectional member area which is generally constant from member end-to-end, means for advancing workpieces through said drum from end-to-end thereof upon drum rotation, means for rotating said drum about its axis, and brush means electrically engaged with said conductive members at said drum end section and connected to an electrical plating circuit to establish an electrical connection between the latter and said drum members at the underside of said drum and a consequent electrical connection with the workpieces engaged with said drum members.
2. Apparatus for continuously plating workpieces, comprising a tank for containing a plating solution, a drum rotatable about a generally horizontal axis and open at both ends for respective receiving and discharging workpieces and having only its lower portion positioned for immersion in the plating solution, said drum having a plurality of longitudinally extending, current-conductive members electrically insulated from each other and arranged about its inner periphery for underlying the workpieces within said drum and the latter being pervious to provide for free flow of the plating solution thereinto, means for advancing workpieces through said drum from end-to-end thereof, anode means immersed in said plating solution and connected to the positive branch of a plating circuit, means for rotating said drum and causing said drum members to follow a circular path successively through a descending first cycle above the drum axis, a descending second cycle below the drum axis, an ascending third cycle below the drum axis and an ascending fourth cycle above thedrum axis, the workpieces in said drum normally lying against and being in electrical engagement with said drum members during their movement through said third cycle, and means successively connecting each drum member to the negative branch of said plating circuit during movement of such member through said third cycle to plate the workpieces in electrical contact with such member and successively connecting each drum member to the positive branch of said plating circuit during movement of such member through said second cycle to remove any plating deposit from such member.
References Cited by the Examiner UNITED STATES PATENTS 2,229,073 1/1941 Gregory 204213 X FOREIGN PATENTS 94,559 10/ 1923 Austria. 194,759 3/1923 Great Britain.
JOHN H. MACK, Primary Examiner.
A. B. CURTIS, W. VAN SISE, Assistant Examiners.