US2853447A - Electropolishing apparatus - Google Patents

Description

' Sept. 23, 1958 H. J. HACKENBURG 2,853,447

ELECTROPOLISHING APPARATUS Filed Aug. 3, 1956 v 5 Sheets-Sheet l INVENTOP HERMAN J HA C K E NBURG @cmkgw ATTORNEY p 1958 'H. J. HACKENBURG 2,853,447

ELECTROPOLISHING APPARATUS Filed Au 331956 0 3 Sheets-Sheet s as o INVENTOI? HERMAN J. HACKENBU/PG ATTORNEY United States Patent 2,853,447 ELECTROPOLISHING APPARATUS Herman J. Hackenburg, Gillette, N. J.

Application August 3, 1956, Serial No. 601,923 Claims. (Cl. 204-214) This invention relates to apparatus for electrolytically polishing articles comprising metals and/or alloys, and more specifically to an anode and cathode arrangement used in the apparatus for expeditiously carrying-on such polishing with a rotating barrel technique.

Heretofore, electropolishing of metallic articles has been generally performed in stationary apparatus. Prior attempts to perform such electropolishing in rotating barrels have been only moderately successful. The absence of satisfactory results in the use of electropolishing apparatus of the barrel type may have been due in part, at

least, to the specific compositions of the electrolytic baths that were then employed. In the rotating barrel technique, the anode and cathode were usually fixed in relative size so that adjustments in the technique were confined to variations of the composition of the electrolytic bath in an endeavor to promote efliciency and .quality. For the most part in prior art electropolishing apparatus, the relative size of the anode and cathode was fixed in a unitary structure thereby permitting adjustment only of the electropolishing techniques in respect to the specific composition of the electrolytic bath at a given moment.

The foregoing operation often resulted in unnecessary expenditures of time and money in an area which tended to effect a partial but not an entirely satisfactory movement in the technique. In instances where the metallic articles polished electrolytically were not intended for exposure to public view in their use, a mediocre appearance was tolerable. In those instances, however, where such metallic articles were intended for, continuous exposure to public view, only metallic articles electropolished to optimum appearance with long life were acceptable. In the latter instance, it frequently happened that a large number of rejects increased the overall electropolishing cost to uneconomical proportions.

Accordingly, the present invention contemplates electropolishing apparatus provided with cathodes adaptable for expeditious adjustment in reguard to size, shapeand location and usable in a rotating barrel technique.

An object of the invention is to promote the efficiency of electrolytical polishing of metallic articles effected in a rotating barrel.

Another object is to improve the quality of the electrolytical polishing of metallic articles achieved in a rotating barrel.

A further object is to provide a facile control for an electrolytical-polishing technique using a rotating barrel.

Still another object is to provide expeditiously the optimum ratio between the exposed surfaces of the cathode and anode mounted on a rotating barrel used in electrolytical-polishing apparatus.

Still another object is to provide an arrangement for expeditiously controlling the ratio between the exposed surfaces of the anode and cathode afiixed to a rotating barrel used in an electrolytical-polishing apparatus.

In a specific embodiment for electrolytically polishing metallic articles with improved eflic'iency and quality effected with a bath of suitable electrolyte, a source of 2,853,447 Patented Sept. 23, 1958 'ice direct current voltage having positive and negative-terminals and a perforate non-conductive barrel rotatable in the electrolytic bath and having a perforated closed end and an open end, the present invention comprises a perforateanode disposed interiorly of the barrel adjacent the perforated closed end thereof in contact with the metallic articles to be electropolished, a rotatable shaft forming an electrical connection for the positive terminal of the voltage source, a non-conductive yoke having one end mounted on the shaft and an opposite end attached to the anode and closed barrel end, an electrical connection included interiorly of the yoke butexposed at both the one and opposite ends thereof in such manner that the exposed electrical connection at the one end is in electrical contact with the shaft while the exposed electrical connection at the opposite end is in electrical contact with the anode, and a plurality of discrete elongated cathodes mounted in spaced relation on the periphery of the barrel and connected together to'constitute a unitary cathode, certain ones of the cathodes being turned-in over approximately one-half of the open end of the barrel and provided with a common electrical termination which is adjacent to but spaced from an end of the shaft, and means connected to such termination and coaxially mountedwith but electrically insulated from the shaft to constitute an electrical connection for the negative terminal of the voltage source. a,

A feature of the present invention is that the rotating barrel is provided with such physical dimensions that the barrel including the anode and work mounted therein may be readily mounted upon and removed from the electrolytic tank by a single workman. I

Another feature is that the cathodes being spaced on the outer' periphery of the rotating barrel containing the work may be so expeditiously adjusted in shape, number and size that an optimum ratio of cathode surface to anode surface may be readily provided, without disturbing the electrolytic bath.

Still another feature is that the peripheral disposition of the elongated cathodes enables them to be interchanged substantially with minimum mechanical difficulty withoutdisturbing the electrolytic bath.

A further feature is that the mounting of the anode interiorly of the rotating barrel on the perforated closed end thereof provides a firm and continuous contact with the positive terminal of the voltage source at all times during the rotation of the barrel.

Still another feature is that the metallic articles to be electrolytically polished are positioned within the rotating barrel always in a facile, continuous and efiicient electrical contact with the anode within the electrolytic bath during the rotation of the barrel.

The invention will be readily understood from the following description when read together with the accompanying drawing in which:

Fig. 1 is a perspective view of a specific embodiment of the invention;

Fig. 2 is a perspective view of a portion of the invention shown in Fig. 1;

Fig. 3 is an elevational view with cutaways of a portion of the invention shown in Fig. 1; i a

Fig. 4 is a schematic circuit showing the electrical connections for the invention illustrated in Fig. l; and

Fig. 5 is a partial elevational view taken along line 5-5 in Fig. 1. i

As illustrated in Fig. l, a bath 10 of suitable electrolyte is contained ina tank 11 mounted on a floor, not shown, in a conventional manner. Shelf 12- made of acid-resistive material and mounted interiorly of the tank at an upper end of one side thereof is provided with an aperture, not shown, for receiving a reduced end 13 of a swivel 14 shown in Figs. 1 and 2. An upper end of the swivel includes a pivot for rotatably mounting a frame 16, and contains a peripheral recess 17 for a purpose that will laterappear. The recess 17 is adapted to receive one end of aplunger 19 which is slidably mounted in an elongated slot 20 provided interiorly of frame 16. The plunger has an opposite end coaxially mounted with a coiled compression spring 21. p g

A finger grip 22 attached to a central portion of the plunger projects through an opening 23 provided in the frame and serves to effect slidable movements of the plunger in slot 20 for a purpose that will presently appear. When the plunger is withdrawn from recess 17 of the swivel, the frame'is disposable at an oblique angle relative to a horizontal surface of shelf 12 as shown in Figs. 1 and 2. When the plunger is disposed in recess 17 of the swivel, the frame will be positioned approximately in a a vertical manner as indicated by the dot-dash lines in Fig. 1. This positioning of the frame is achieved by the location of recess 17 in an uppermost peripheral portion of the swivel. It will be understood that compression spring 21 retains the plunger in recess 17 in which theplunger may be disposed at a given time whereas a withdrawal of the plunger against the force of the compression spring by the finger grip from either recess enables the frame to be rotated in a clockwise or counter-clockwise direction relative to shelf 12, depending on the initial position of the frame, to either the oblique or vertical positionfor a purpose that will be presently explained. v

In accordance with a specific embodiment ofthe present invention, it will be'seen in Figs. 1 and 2 that the frame positioned obliquely relative to shelf 12 or 'thehorizontal surface of the electrolytic bath has its free end bent approximately at 90 degrees andterminated substantially in an inverted U-shaped portion 31. Of the latter, legs 32 and 33 support suitable ball bearings '34 and 35, respectively, for one end of a sha'ft'36. On the latter shaft adjacent bearing 34 is fixedly mounted'worm gear 37 adapted to engage worm 38 in a manner and for a purpose that will be subsequently mentioned.

Referring to Fig. 3, the free end of shaft 36' is formed with an integral coaxial flange 42 adapted to ride against an inner surface of leg 33. This shaft is also formed with an integral portion 43 extending coaxially therewith and normally to'fiange42. The shaft portion 43 is provided with a rectangular outer shape'a'nd an interior rectangular opening for purposes that will'presentlyappear. Positioned externally of shaft portion 43 and adjacent flange 42 is an insulating collar 44 formed with adepressed central portion 45 carrying collector ring 46 'of electrically conductive material. This'r'im' is secured in position on collar 44 by an elongated "screw 47 which also serves a further purpose that will'be "subsequently mentioned.

Yoke 48 in Fig. 3 comprises an-insulating material preselected for mechanical strength and having positioned axially therewithin electrically conductivecores 51 and 5111 which are formed to terminate at certain corresponding ends in an electrically conductive ring 52 adjacent shaft portion 43. Ring 52 has an axial rectangular opening which accommodates therein the corresponding rectangular outer shape of shaft portion 43 and thereby enables yoke 48 to be mounted-on shaft portion 43 adjacent to insulating collar 44. Ring 52 is secured to insulating collar 44 by a plurality of screws 49, 49 extending through a metallic plate 50 and anchored in the latter insulating collar. Corresponding opposite ends of cores 51 and 51a are also formed to terminate in a circular plate 53 formed'with an integral annular portion 53a.

A perforate barrel 54 comprising an insulating and acid-resistive material preselected for mechanical strength has a perforated closed end and an 'open end as shown in Figs. 2 and 3; A perforate anode 55 is disposed on the inner surface of the closed perforate end of the barrel, and both the anode and latter barrel end are 4 secured to the inner surface of annularportion-53a-by a plurality of metallic and acid- resistive screws 56, 56. These screws provide an electrical connection via yoke 48 between anode 55 and shaft 36 for a purpose that will later appear.

As shown in Figs. 1 and 2, worm gear 37 is meshed with worm 38 which is formed integrally with a shaft 57 whose opposite ends are-rotatably supported in suitable bearings provided in bent-in and parallel sides 58 and 59 of a bracket 60. This bracket is mounted on a shelf 61 providedat one end and on the top of tank 11 and comprising a suitable insulating and acid-resistive material such, for example,-as specially treated wood or the like. The worm shaft 57 is connected via clutch 62 and driving mechanism 63 to electric motor 64. A fingeractuated switch 65 controls the energization of the motor through electrical cable 66 from aconventional commercial AI-C. supply, not shown.

Referring to Figs. 1 and 5, it will be seen that shaft 36 rests rotatably on a bearing provided by the sloping inner sides of the two legs of a bifurcated member '69. This member is vertically adjustable on bracket 60 by means of a pair of'vertically elongated slots 70, 70 provided in member 69 and a pair of screws 71, 71 mounted in bracket 60 and projecting through the slots. Thus, the shaft 36 may be varied in position as desired substantially in a vertical direction by appropriately. adjusting the positions of the slots 70, 70 of member 69 on associatedscrews 71, 71. This will tend to control the amount of meshing between gears 37 and 38 and thereby establishafirm mechanical and electrical. connection therebetween for. a purpose that will later appear.

Asshown in Figs. 1 through 4, a circuit connecting the positive terminal of direct-'currentvoltage source 73 in Fig. 4 to anode 55in Figs. 2.iand 3i'may.be:traced-.-as follows: in-sequence, lead 72 connecting the positive .terminal of voltage source 73 to side-59 ofbracketi61, worm 38, worm gear 37, shaft 36, flange-42, shaft portion- 43, terminating ring 52 of yoke- 48gcores 51' and 51a, terminating plate 53, annular portion 53a, screws 56, 56 and anode 55. This circuit serves a'purposethat will be hereinafter pointed out. In the-'afore tra'ced circuit it will be noted that clutch 62 in Fig. '1 insulates electrically voltage source 73' from driving mechanism 63 and motor 64 attached thereto. It-will be understood that voltage source 73 provides 'a direct-cu'rrentroltage of preselected magnitude suitable for'eifectingthe electrolytical electropolishing hereinafter described, and variable in magnitude by a-conventionally adjustableresistor, not shown, if so desired. A plurality of elongatedmectangular " discrete cathodes 75, 75 of electrically conductivematelial such as copper or thelike is disposed in spacedrelation about'the outer periphery of the barrel in such. manner" that one side-of smaller dimension is disposed substantiallywangentially to the periphery 'of thebarr'el and the axes of longer dirnensions are disposed substantiallyrin parallel relation with the axis of rotation of the barrel; as 'illus' trated in Figs. 1, 2: and 3. For this purpose, rims 76 and 77 are rigidly affixed externally to the opposite ends ofthe barrel; and right-angle cut-out portions 73 are provided at opposite corresponding ends ofeachcathode. These cut-out portions enable the cathodes tofit snuglyand firmly on thebarrel-rims and thereby to be disposed in length substantially coextensively withthe. lengthof the barrel.

Adjacent cathodes are held in spaced relationby a pinrality of spacers 79, 79 made of hollow electrically insulating and acid-resistive material. The spacers are mounted coaxially-on a pair of annular tie rodsfitl and 81 made of copper or the like, which comprises an" electrically conductive material, and disposed aboutthe outer periphery of the barrel inspaced relation along the rotational axis thereof. It will be understood that the cathd odes 75, 75 are provided with suitable holes 68, 68 as shown in Fig. 2 to accommodate the tie rods with a tight fit to constitute a suitable electrical connection for a purpose that will be presently mentioned.

The free ends of each of tie rods 80 and 81 are threaded and disposed in opposed relation on opposing surfaces of cathodes 82 and 83 which comprise the integral sides of a channel 84 made of copper or the like which comprises an electrically conductive material, as seen in Figs. 2 and 3. It will be apparent that right-angle cut-out portions 78 are also provided on the opposite corresponding ends of cathodes 82 and 83 whereby the latter are enabled to fit snugly and firmly against the barrel rims 76 and 77. Nuts 85, 85 are mounted on the threaded opposing ends of the tie rods. This secures all cathodes together firmly as a unitary cathode structure adjacent the outer periphery of the barrel, as the latter is rotated for a purpose that will be later mentioned.

As illustrated in Fig. 2, a preselected group of cathodes 75 have corresponding end portions 75a extended and turned-in over the edge of the barrel in a radial direction toward the axis of rotation thereof over an area equal substantially to one-half of the open end thereof while the remaining one-half of the open barrel end remains uncovered or unobstructed for a purpose that will presently appear. A plurality of fins 90, 90 is disposed adjacent the open barrel end in proximity of turned-in portions 75a, each fin being made of copper or the like and comprising an electrically conductive material. Of these t'ached to an outermost end of one turned-in portion 75a and .an opposite end formed in an angle portion 900. Similarly a second fin 90d has one end suitably connected to a turned-in portion 75a of cathode 83 and an opposite end formed in an angle portion in a manner like that of angle portion 900.

Thus, each of the remainder of fins 9t), 90 has one end attached to one turned-in portion 75a and an opposite end formed generally like angle portion 90c. All of the corresponding opposite ends of fins 9b, 90, i. e. those formed generally like angle portions 900 are mechanically and electrically secured together in a firm unitary engagement via screws 91, 91 to constitute a common electrical termination for all cathodes 75, 75. This commontermination is disposed substantially adjacent to but spaced from the free end of shaft portion 43, on which yoke 48 is mounted and includes at least one point coincident with the axis of rotation of the barrel. While some cathodes are composed of the two parts above described, it will be evident that they could equally as Well be formed of one part. It will be thus apparent that the remaining one-half of the open end of the barrel is unobstructed to permit loading and unloading of work, i. e., the articles to be electrolytically polished, in a manner that will be subsequently described. An electrically conductive strap 92 connects one of the screws 91 of the common termination and thereby all fins and cathodes to a point lying between the head of screw 93 and an electrically insulating strip 94 disposed adjacent metallic plate 50, as seen in Fig. 3. In the latter figure, screw 93 passes through a hole, not shown, in insulating strip 94 and is anchored in one end of a metallic insert 95 of rectangular configuration positioned in an accommodating rectangular coaxial opening formed in a rectangular sleeve 96 of electrically insulating material, both the latter insert and sleeve being positioned internally of the rectangular opening formed interiorly of shaft portion 43, as previously mentioned. An opposite end of the metallic insert 95 serves to anchor the free end of elongated screw 47 which provides a suitable electrical connection between metallic insert 95 and collector ring 46.

It will be understood that screw 47 passes through a hole, not shown, in shaft portion 43 of such size and shape as to preclude a contact between the screw and shaft portion. Also, it will be understood that screw 47 and insert 95 are electrically insulated from any contact with shaft portion 43 and/ or yoke 48. Thus, it will be apparent from the afore-described structure that all cathodes 75 are connected in an electrical circuit to collector ring 46.

The collector ring 46 is frictionally engaged substantially on diametrically opposite points by a pair of fingers or brushes 97, 97 comprising flexible metallic material and secured to an electrically insulating strip 98 which is suitably afiixed to the shelf 61 on the tank. A metallic clip 99 connects the fingers 97, 97 via lead 100 and a single pole single throw switch 102 to the negative terminal of voltage source 73. Each of brushes 97 is formed with an integral turned-out portion 101, Fig. 2, to permit collector ring 46 and the afore-described mounting therefor to pass expeditiously into and out of engagement with the brushes 97, 97 as the mounting frame 16 is rotated on its pivot 15 for a purpose that will presently appear.

In operation of the specific embodiment of the invention as afore-described, it will be understood that initially switches 65 and 102 are actuated by a workman to disconnect the A.-C. supply from motor 64 and the D.-C. voltage source 73 from the associated anode and cathode, respectively; and that finger grip 22 has been appropriately adjusted by the workman to permit mounting frame 16 to rotate its pivot 15 in a counter-clockwise direction to the vertical position shown by the dot-dash lines in Fig. 1 and thereby disengage worm gear 37 from worm 38, as the collector ring 46. is withdrawn from contacting brushes 97, 97.

This will enable the workman to withdraw reduced end 13 of swivel 14 from shelf 12 and thereby carry away the barrel from the tank of electrolyte. This may be expeditiously achieved for the reason that the barrel has an outside diameter of the order of eight inches and and overall length of approximately twelve inches. The

a frame and barrel are then carried to a suitable point for loading work thereinto. The bath of electrolyte will now be assumed to comprise chemical constituents suitable for the electrolytic polishing of work consisting of small metallic articles, such bath being of a type known in the art.

Assuming further that the barrel is initially empty, it can be loaded to a suitable amount by putting thereinto the articles to be electrolytically polished through the unobstructed one-half of the open end of the barrel which was hereinbefore mentioned. Then, the reduced end 13 of swivel 14 is re-inserted into the aperture of shelf 12 whereupon mounting frame 16 is returned to the vertical position shown by the dot-dash lines in Fig. 1. Next, finger grip 22 is appropriately adjusted in the manner above-mentioned by the workman to permit mounting frame 16 to rotate in a clockwise direction on its pivot 15 to the angular position shown in full lines in Fig. 1.

\ Now, the articles in the barrel are disposed in mechanical and electrical engagement with each other and with the anode 55 to constitute eifectively a unitary and composite anode (positive terminal) for the electro-polishing system hereinbefore described.

This will enable worm gear 37 and collector ring 46 to re-engage worm 38 and fingers 97, 97, respectively. Closure of switch 102 will connect the anode and cathode to the positive and negative terminals, respectively, of voltage source 73. Finally, switch 65 is operated to connect the'A.-C. supply to motor 64 whereupon the barrel is rotated with the anode and work in electrical contact with each other in the electrolytic bath at a preselected R. P. M. speed. Thus, the articles disposed in the interior of the barrel are electrolytically polished in the well-known manner.

An addition to or a subtraction from the number of cathodes positioned externally of the barrel in the manner above-described enables a facile adjustment to an.

7 optimum value of the ratio of cathode surface to the surface anode, the latter surface including both anode plate 55 and articles to be electrolytically polished. A further adjustment of such ratio may also be expeditiously achieved by varying the physical size of the individual cathodes, as well as combining cathodes of different physical sizes in the array disposed peripherally externally of the barrel as shown in Figs. 1 and 2. Moreover, it will be I apparent that the articles remain in electrical contact With-each other and with the anode at all times during the rotation of the barrel.

It will be understood that while the invention has been described with reference to a particular embodiment, other embodiments will be evident to those skilled in the art.

What is claimed is:

1. In apparatus fo-r'electropolishing work comprising a tankadapted to contain a bath of electrolyte, a source of direct current voltage, a rotating shaft connected to one terminal of said source, a perforate non-conductive barrel having a closed end and an open end for holding said work, a perforate anode positioned interiorly of said barrel adjacent said closed barrel end in contact with said work, a non-conductive support, an electrical conductor mounted interiorly of said support and exposed at two spaced surface portions of said support to provide two spaced acreas for electrical connections, one of said areas being electrically connected through said closed barrel end to said anode and thereby mounting said barrel on said support, the second of said areas-being connected to one end of said shaft for connecting said anode to said shaft and mounting said support on said shaft, said mountingof said support on said one shaft end also mounting said barrel coaxially with said shaft for rotating said barrel, anode and work in said bath of electrolyte While at the same time connecting said anode to said one terminal of said source, a plurality of discrete cathodes mounted in spaced relation on an external periphery of said barrel and electrically connected together to constitute a unitary cathode, said cathodes comprising discrete elongated members extending substantially coextensively with the length of said barrel and having their longer axes disposed substantially in parallel relation with the rotational axis of said barrel, and electrically conductive means mounted on said one shaft end and elec trically insulated therefrom, said last-mentioned means comprising an electrical connection mounted interiorly of said one shaft end and terminating in two electrical contacts mounted in spaced relation exteriorly on said shaft, one of said contacts being mounted on the face of said one shaft end and permanently electrically connected to said unitary cathode, and the second of said contacts being mounted on the periphery of said one shaft end and being slidably electrically connected to another terminal of said source for electrically connecting said unitary cathode to said last-mentioned terminal during the rotation of said barrel, anode and work in said bath of electrolyte by said shaft.

2. The apparatus according to claim 1 in which at least one of said cathode members has an end turned-in over said open end of said barrel and terminated in a section substantially coincident with said face of said one shaft end but spaced therefrom, said one contact being permanently electrically connected to said last-mentioned section and thereby to said unitary cathode.

3." The apparatus according to claim 1 in which the ends of a preselected group of adjacent cathode members of said plurality of cathode members are turned-in over said open end of said barrel for an area equal approximately to one-half of said last-mentioned open barrel end, said turned-in ends terminating in a common electrical section substantially coincident with said face of said one shaft end but spaced therefrom, said one contact being permanently electrically connected to said common section and thereby to said unitary cathode.

4. The apparatus according to claim 1 in which said elongated cathode members have rectangular cross-seotions and are mounted on the external periphery of said barrel with sides of the smaller dimension engaging respectively different portions of the external periphery of said barrel.

5. The apparatus according to claim 4 in which said elongated cathode members have sides of the larger dimension extending from the respectively different portions of the external periphery of said barrel substantially in radial directions relative to the rotational axis of said barrel.

6. In apparatus for electropolishin-g work comprising a tank adapted to contain a bath of electrolyte, a source of direct current voltage having a positive terminal and a negative terminal, a perforate anode, a perforate nonconductive barrel having a closed perforate end and being open at the other end for holding said work, said anode being positioned interiorly of said barrel adjacent said closed end thereof for engagement with said work, a rotatable shaft electrically connected to said positive terminal, a non-conductive yoke including an electrically conductive core exposed on two different surface portions of said yoke to constitute two spaced areas for electrical connections on said yoke, said barrel being mounted on said yoke, one of said last-mentioned two areas being electrically connected through said closed end of said barrel with said anode and thereby holding said barrel mounted on said yoke, the other of said last-mentioned two areas being connected to one end of said shaft for electrically connecting said anode to said positive terminal and mounting said yoke on said one shaft end, said last-mentioned mounting of said yoke serving to mount said barrel and anode coaxially with said shaft for rotating said barrel, anode and work in said bath of electrolyte, a plurality of discrete cathodes mounted in spaced relation on an external periphery of said barrel and connected together electrically to constitute a unitary cathode, certain adjacent cathodes of said plurality of cathodes having end portions turned-in, over the open end of said barrel for an area equal approximately to onehalf of said open end of said barrel, said turned-in end portions terminating in a common electrical portion disposed adjacent to but spaced from said one shaft end so that substantially the remaining one-half of the open end of said barrel permits the insertion of said work into said barrel and the removal of said work therefrom, and electrically conductive means mounted on said one shaft end and electrically insulated therefrom, said lastmentioned means comprising substantially right-angle conductive means mounted interiorly of said one shaft end, said last-mentioned means having one end terminating on the face of said one shaft end and the opposite end terminating coextensively with the periphery of said one shaft end, said terminations of said one and opposite ends of said right-angle means being mounted substantially coaxially with said shaft, said last-mentioned terminating one end of said conductive means being permanently electrically connected to said common cathode portion, and said last-mentioned terminating opposite peripherally coextensive end of said conductive means being slidably electrically connected to said negative terminal for electrically connecting said unitary cathode to said last-mentioned terminal during the rotation of said barrel and anode and work in said bath of electrolyte by said shaft.

7. The apparatus according to claim 6 in which said plurality of discrete cathodes comprises a plurality of discrete elongated members having rectangular cross-sections and mounted on an external periphery of said barrel with narrow sides engaging respectively different peripheral portions of said barrel and with Wider sides extending from the respectively different peripheral portions of said barrel substantially in radial directions relative to rotational axis of said barrel, said certain adjacent cathodes comprising portions substantially coextensive with the length of said barrel and said turned-in end portions disposed substantially at right angle relative to said last-mentioned coextensive portions for an area approximating one-half of said open end of said barrel, and the remaining cathodes of said plurality of cathodes being substantially coextensive with the length of said barrel so that substantially the remaining one-half of said open end of said barrel permits the insertion of said work into said barrel through said last-mentioned onehalf open barrel end and the removal of said work from said barrel through said last-mentioned one-half open barrel end.

8. The apparatus according to claim 6 in which said terminating opposite peripherally coextensive end of said right-angle means comprises an electrically conductive collar mounted coaxially with and electrically insulated from the periphery of said end of said shaft, and which includes resilient means electrically frictionally engaging said collar during the rotation of said shaft for electrically connecting said unitary cathode to said negative terminal.

9. Apparatus for electropolishing Work comprising a tank adapted to contain a bath of electrolyte, a source of direct current voltage having positive and negative terminals, a perforate anode, a perforate non-conductive barrel having a closed perforate end and being entirely open at the opposite end for holding said work, said anode being positioned interiorly of said barrel on said perforate end thereof and having said work in engagement with said anode, a rotatable shaft electrically connected to said positive terminal of said source, a nonconductive yoke including an electrically conductive core exposed at two spaced portions on said yoke' to constitute two spaced electrical connection areas, said barrel being mounted within said yoke adjacent one of said two areas, said last-mentioned one area being electrically connected through said closed end of said barrel to said anode and thereby holding said barrel mounted on said yoke, the other of said two areas being formed with an axial opening of preselected configuration for accommodating a corresponding configuration formed on one end of said shaft to electrically connect said anode to said shaft and thereby connect said anode to said positive terminal, said last-mentioned connection also serving to mount said yoke on said shaft and thereby mount said barrel coaxially with said shaft, said shaft rotating said barrel, anode and work in said bath of electrolyte while at the same time continuing the connection of said anode to said positive terminal, a plurality of discrete elongated cathodes positioned in spaced relation on an external periphery of said barrel and electrically connected together to form a unitary cathode, said cathodes having at least a length substantially coextensive with the length of said barrel, a preselected group of said cathodes having corresponding ends turned-in over the open end of said barrel in a radial direction toward the axis of rotation of said barrel, a plurality of electrically conductive members having corresponding ends connected to said cathode turned-in ends and having opposite ends joined together to form a common electrical termination for said unitary cathode adjacent to but spaced from said one shaft end, said members and cathode turned-in ends covering an area equivalent substantially to one-half of said open end of said barrel so that the remaining one-half of said last-mentioned open barrel end is available for loading work therethrough into said barrel and unloading work therethrough from said barrel, electrically conductive means mounted on said one shaft end and electrically insulated therefrom, said last-mentioned means comprising a collector ring mounted externally of and coaxially with said shaft, an electrical contact mounted on the face of said one shaft end, and an electrical conductor mounted interiorly of said one shaft end for electrically connecting said collector ring and contact, an electrically conductive strap for connecting said common termination to said contact, and a pair of brushes disposed in spaced relation on the periphery of said collector ring for electrically slidable engagement therewith, said members, strap, contact, conductor, collector ring and brushes electrically connecting said unitary cathode to said negative terminal of said source during the rotation of said barrel, anode and work in said bath of electrolyte by said shaft.

10. The apparatus according to claim 9 which includes a driven gear mounted on the free end of said shaft, a driving gear meshed with said driven gear, said shaft being electrically connected through said driven and driving gears to said positive terminal of said source, and a motor mechanically coupled to said driving gear for driving said driven gear and thereby rotating said shaft, said motor being electrically insulated from said last-mentioned positive terminal of said source.

11. The apparatus according to claim 10 in which said driving gear and pair of brushes are mounted on said tank, and which includes a mounting frame having one end connected to said shaft and an opposite end pivotally mounted on said tank, said mounting frame being movable on said pivoted opposite end thereof in one direction for engaging said driven gear and collector ring with said driving gear and pair of brushes, respectively, to dispose said barrel, anode and work in said bath of electrolyte, said mounting frame being movable on said pivoted opposite end thereof in an opposite direction to disengage said driven gear and collector ring from said driving gear and pair of brushes, respectively, to withdraw said barrel, anode and work from said bath of electrolyte, and adjustable means mounted on said tank for controlling the amount of meshing between said driven and driving gears to provide a firm mechanical and electrical engagement therebetween.

12. The apparatus according to claim 11 in which said pivotally mounted opposite end of said mounting frame is detachable from said tank whereby said barrel is disengaged from said tank for the loading of said work into said barrel and the unloading of said work therefrom through said remaining one-half open end of said barrel.

13. The apparatus according to claim 1 in which said electrical connection in said one shaft end has substantially a -degree configuration.

14. The apparatus according to claim 13 in which said electrical connection of 90-degree configuration in said one shaft end comprises two legs, one leg being disposed substantially coaxially with said one shaft end and the other leg being positioned substantially normally to said one leg.

15. The apparatus according to claim 14 in which said one contact is mounted on the free end of said one leg on the face of said one shaft end, and said second contact is attached to the free end of said other leg and mounted coextensively with the periphery of said one shaft end, said one and second contacts being mounted coaxially with said one shaft end.

References Cited in the file of this patent UNITED STATES PATENTS 981,004 Reid Ian. 10, 1911 1,254,046 King Jan. 22, 1918 1,522,422 Daniels Jan. 6, 1925 1,525,271 Daniels Feb. 3, 1925 1,583,930 Iantz et a1 May 11, 1926 1,936,382 Daniels Nov. 21, 1933

Claims (1)

1. IN APPARATUS FOR ELECTROPOLISHING WORK COMPRISING A TANK ADAPTED TO CONTAIN A BATH OF ELECTROLYTE, A SOURCE OF DIRECT CURRENT VOLTAGE, A ROTATING SHAFT CONNECTED TO ONE TERMINAL OF SAID SOURCE, A PERFORATE NON-CONDUCTIVE BARREL HAVING A CLOSED END AND AN OPEN END FOR HOLDING SAID WORK, A PERFORATE ANODE PLOSITIONED INTERIORLY OF SAID BARREL ADJACENT SAID CLOSED BARREL END IN CONTACT WITH SAID WORK, A NON-CONDUCTIVE SUPPORT, AN ELECTRICAL CONDUCTOR AMOUNTED INTERIORLY OF SAID SUPPORT AND EXPOSED AT TWO SPACED SURFACE PORTIONS OF SAID SUPPORT TO PROVIDE TWO SPACED ACREAS FOR ELECTRICAL CONNECTIONS, ONE OF SAID AREAS BEING ELECTRICALLY CONNECTED THROUGH SAID CLOSED BARREL END TO SAID ANODE AND THEREBY MOUNTING SAID BARREL ON SAID SUPPORT, THE SECOND OF SAID AREAS, BEING CONNECTED TO ONE END OF SAID SHAFT FOR CONNECTING SAID ANODE TO SAID SHAFT AND MOUNTING SAID SUPPORT ON SAID SHAFT, SAID MOUNTING OF SAID SUPPORT ON SAID ONE SHAFT END ALSO MOUNTING SAID BARREL COAXIALLY WITH SAID SHAFT FOR ROTATING SAID BARREL, ANODE AND WORK IN SAID BATH OF ELECTROLYTE WHILE AT THE SAME TIME CONNECTING SAID ANODE TO SAID ONE TERMINAL OF SAID SOURCE, A PLURALITY OF DISCRETE CATHODES MOUNTED IN SPACED RELATION ON AN EXTERNAL PERIPHERY OF SAID BARREL AND ELECTRICALLY CONNECTED TOGETHER TO CONSTITUTE A UNITARY CATHODE, SAILD CATHODES COMPRISING DISCRETE ELONGATED MEMBERS EXTENDING SUBSTANTIALLY COEXTENSIVELY WITH THE LENGTH OF SAID BARREL AND HAVING THEIR LONGER AXES DISPOSED SUBSTANTIALLY IN PARALLEL RELATION WITH THE ROTATIONAL AXIS OF SAID BARREL, AND ELECTRICALLY CONDUCTIVE MEANS MOUNTED ON SAID ONE SHAFT END AND ELECTRICALLY INSULATED THEREFROM, SAID LAST-MENTIONED MEANS COMPRISING AN ELECTRICAL CONNECTION MOUNTED INTERIORLY OF SAID ONE SHAFT END AND TERMINATING IN TWO ELECTRICAL CONTACTS MOUNTED IN SPACED RELATION EXTERIORLY ON SAID SHAFT, ONE OF SAID CONTACTS BEING MOUNTED ON THE FACE OF SAID ONE SHAFT END AND PERMANENTLY ELECTRICALLY CONNECTED TO SAID UNITARY CATHODE, AND THE SECOND OF SAID CONTACTS BEING MOUNTED ON THE PERIPHERY OF SAID ONE SHAFT END AND BEING SLIDABLY ELECTRICALLY CONNECTED TO ANOTHER TERMINAL OF SAID SOURCE FOR ELECTRICALLY CONNECTING SAID UNITARY CATHODE TO SAID LAST-MENTIONED TERMINAL DURING THE ROTATION OF SAID BARREL, ANODE AND WORK IN SAID BATH OF ELECTROLYTE BY SAID SHAFT.

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