US2199487A - Apparatus for electroplating metallic articles - Google Patents

Description

May 7, 1940. c. L. ETCHJSON APPARATUS FOR ELECTROPLATING METALLIC ARTICLES 6 Sheets-Sheet l Filed July 2'7, 1937 IN VEN TOR.

ATTORNEY @0403 grew Q: BY

May 7, 1940. v c. L. E'i'cHlsoN 7 2 1 9,487

APPARATUS FOR ELECTROPLATING METALLIC ART ICLES Filed July 27, 1937' 6 Sheets-Sheet 2 nun...

in INVENTOR.

W 194i? c. L. ETCHISON 2.199A87 APPARATUS FOR ELECThOPLATING METALLIC ARTICLES Filed July 27. 19,37 s Sheets-Sheet s JNVENT0R. @axof 5240/ swine w,

P1? BY 6 Sheets-Sheet 4 MW w M wists v w \m ww WMMM/ m Us m A w w Q MW, v4 7 A k Ww w .Qw mm, m 1mm. Q% mw M V \4 w May 7', 1940. (2.1.. E'rcmscm APPARATUS FOR ELECTROPLATING METALLIC ARTICLES Filed July 2'7, 1937 Q y 1940- c. L. ETCHISON 2.199.487

' APPARATUS FOR ELECTROPLATING METALLIC ARTICLES i I Filed July 27, 1937 GSheets-Sheet 5 n I IIIIIIII'I'IIIIIII'IIIIA m INVENTOR.

@cvzof' 3, 8424 100w, I 5*. 9 BY 7, 1940- x H c. ETCHISVON 4 2.193487 APPARATUS FOR ELECTROPLATING METALLIC ARTICLES Fil ed July 27, 1957 6 Sheets-Sheet 6 BY 6 W ,ZUTORNEY Patented May 7, 1940 APPARATUS FOR ELECTROPLATING METALLIC ARTICLES Carol Lee Etchison, Frederick, Md., assignor, by

mesne assignments, to United Chromium, Incorporated, New York, N. Y., a corporation of Delaware Application July 27, 1937, Serial No. 156,035

5 Claims.

My invention relates broadly to an improved apparatus for electroplating metallic articles and more particularly to a system and apparatus for increasing the quality and speed of electroplating of metallic articles.

' One of the objects of my invention is to provide apparatus for immersing and removing metallic articles with respect to an electroplating,

bath in which the activation of the electroplating bath is controlled automatically according to the immersion or removal of the articles with respect to the plating bath.

Another object of my invention is to provide means for facilitating the electroplating of metallic articles wherein the metallic articles may 'be mounted upon a relatively lightweight frame which is readily attachable or removable with. respect to an anode supporting frame with automatic means for electrically connecting the articles to be plated, as cathodes, in the electroplating bath upon immersion of the articles in the electroplating bath.

Still another-object of my invention is to provide apparatus for removably mounting articles to be plated in an electroplating bath and automatically connecting such articles as cathodes in the electroplating bath immediately upon immersion of the articles in the bath and disconnecting the articles as cathodes immediately upon the withdrawal of the articles from the plating bath. r

A further object'of my invention is to provide a construction of carrier for articles in an electroplating bath in which the weight of the articles is substantially counterbalanced through all positions of movement of'the articles into and out of the electroplating bath.

A still further object of my invention. is to provide an arrangement of carrier for articles to be immersed into or withdrawn from an electroplating bath'in which different degrees of coun terbalance is rendered eflective for different posian electroplating system as set forth more fully in the specification hereinafter following byreference to the accompanying drawings in which:

Figure 1 is a side elevation showing the article i to be plated completely immersed in the electroplating bath and'the switch to the energization circuit closed; Fig. 2 is a'similar view showing the article carrying frame partially'raised and the switch to the energization circuit open; Fig. 3

frame completely i'aised out of the'electroplating bath; Fig. 4 is a side elevation showing the articles in electroplating position partially in section on an enlarged scale, with parts broken away to disclose the interior; Fig. 5 is a plan view of the tank for the electroplating bath and adjacent parts; Fig. 6 is a horizontal section view on line 6--6 of Fig. 4; Fig. -'7 is a detail horizontal view taken on line 1-4 of Fig. -13 showing the manner of insulating the structural parts of the main supporting frame from the anodes carried by the .main frame; Fig. 8 is a transverse vertical section taken on line 8-8 of Fig. 1, showing the article carrying frame immersed in. the electroplating bath; Fig. 9 is a similar view showing the article carrying frame raised out of the electroplating bath; Fig. 10 is a transverse vertical section on an enlarged scale taken on line ill-I0 of Fig. 1; Fig. 11 is a horizontal sectional view taken on line I I-ll of Fig. 1; Fig. 12 is a transverse vertical section taken on line l2-l2 of Fig. 1; Fig. 13 is a front view of the angle iron anode supporting frame upon which the article carrying frame is superimposed when in electroplating position; Fig. 14 is a transverse vertical section taken on line [4-44 of Fig, 13; Fig. 15 is a front view of the article carrying frame; Fig. 16 is a horizontal section taken on line |6I6 of Fig. 15; Fig. 17 is an edge view of the article carrying frame; Fig. 18 is a transverse vertical section taken on line |8-- l8 of Fig. 15; Fig. 19 is a detail fragmentary sectional view showing more particularly how the articles to be. plated are suspended and electrically con-' 'nected as cathodes, taken on line i9--l9 of Fig.

.15; and Fig.20 is a detail fragmentary perspective view of a portion of the insulated articl carrying frame.

My invention is directed particularly to apparatus for economicaloperation of a chromium plating bath on a quantity production basis with minimum consumption of time for each plating operation. While I have developed the 'apparatus herein described particularly for chromium plating, my invention is broader than the paris a similar view showing, the article, carrying I provide a system of air ducts 5 extending along the side walls of the tankI and across one end thereof and interconnected by a common suction discharge connection 6 as illustrated more particularly in Fig. 5.

I provide a pair of positive bus bars I extending longitudinally of tank I in spaced relation to each other and in positions spaced from but adjacent the side walls of the tank. I mount insulated supports 8 for the positive bus bars I on brackets 9 mounted" adjacent opposite ends of tank I. The positive bus bars 1 are interconnected atone end by means of the positive connecting bus indicated at III.

The tank I is mounted adjacent the fioor.of

' the plating room and beneath an overhead frame II supported from the ceiling structure by suitable suspension means indicated generally at I2.

I mount positive connecting buses from the.

overhead frame II in a position depending therefrom. The buses I4 are interconnected with the bus III to the positive side of the potential source through a conductor indicated generally at I5.

To facilitate the handling of the articles to be plated, as will be hereinafter described in more detail, I provide a foldable, extensible and retractable frame I6 containing links pivotally connected at I 'I with the positive. depending buses I4 and provided with pivoted interconnections at I8. The lower .ends of the links are nivotally connected with respect to a horizontal bar I9 through pivotal connections on brackets 20. carr ed by bar I9 as indicated by the pivotal connections 2I.

I provide cables 22 connected to brackets 20 on bar I9 and extending through guide pulleys 23 which are journaled on overhead frame II. For purposes of controlling the cables 22, I provide a rotary'member 24 which is journaled as indicated at 25 with. respect to the overhead frame II.

The rotary member 24 comprises two interconnected portions, that is, an eccentric cam portion 26 and a cylindrical drum portion 21. There is a connection 28 between cables 22 and the extreme end of eccentric cam 26. The eccentric cam 26 has a contacting face portion 29 whose function is shown more clearly in Fig. 2. In the positionshown in Fig. 1 wherein the articles to be plated are entirely immersed in the plating bath, the rotary member 24 has the eccentric cam portion 26 thereof extending substop 3| on the overhead frame I as shown in Fig. 3.

The cylindrical drum portion 21 of the rotary member 24 has a strap or belt 32 secured to a peripheral portion of drum 2'! as indicated at 34 me. position substantially on an obtuse angle with respect to the axis of the extended portion 28 constituting the eccentric cam as indicated in Fig. 3. The strap or belt has a weight 33 attached to the end thereof. As illustrated in Figs. 1, 2 and 3, weight 33 acts on a'radius equal to the diameter of the cylindrical drum 2I urging the work carrying frame to elevated position and counterbalancing the entire assembly for permitting the work carrying frame to be readily elevated from immersed position. The mass of the work carrying frame acts differentially through radii which effectively change according to the radius of the cylindrical drum portion 21 or the distance between the axis of rotary member 24 and the extremity of the eccentric cam 26. By reason of this differential leverage condition the effective weight of the work or article carrying frame may be employed to advantage when the work or article carrying frame is immersed in the electroplating bath for establishing substantial electrical contact betwen the engaging hook members of the work or article carrying frame and the negative terminal connecting means as will be described hereinafter in more detail, which'I have illustratedin the conditions set forth in Fig. 1. However, when the work or article carrying frameand anode assembly is raised only slightly out of the electroplating bath, a complete counterbalance is obtained as illustrated under the conditions shown in Figs. 2 and 3 because of the fact that the same effective radius is exerted about the journal of the rotary member 24 by both the mass of the work and article carrying frame and movable anode assembly on the one hand and the counterbalance weight 33 on the other hand.

Referring more particularly to Figs. 13-20, I

provide suspension members and positive bus bar connections" leading from the anodes 48 on the frame 31 and connected at 36 as illustrated in Figs' 1, 2 and 3 to horizontal bar I9. The frame .31 has horizontallyextending members 38 insulatingly mounted through insulation blocks 39. Bolts 40 interconnect the horizontally extending members 38 and frame 31. Each bolt 40 passes through an insulated sleeve 4| surrounding the bolt 40. Insulated washers 42 and 43 are provided adjacent the headed end of the bolt and the nut engaging end of the bolt so that a secure mechanical mounting is provided for horizontally extending members 38 while electrically insulating members 38 from the frame 31. Nuts44 engage the bolts '40 for securing members 38 in position with respect to frame 31. The bus bars are secured to the'members 38 by suitable means such asrivets 46. The bus bars 35 and horizontally extending angle members 4.5 secured thereto are spaced to embrace opposite sides of horizontally extending members '38. The angle members 45 provide mechanical supporting means and electrical connecting means for the anodes 48 through members 41 which project from angle member 45. Anodes 48 formed from lead and may be conveniently spaced to correspond to the contour of the article to be plated. The bus bar connections 35 are electrically insulated from frame 31 through insulated spacer blocks 49. A mechanical connection is established between bus bars 35 and frame 3'! through bolt members 49a ing rim portions 65 which engage notches 63 inarranged in a manner similar to bolts 41 and as illustrated in Fig. '1. The interconnecting bolts 48a are electrically insulated from bus bars 35 and frame 31 sothat frame 31 cannot form part of theelectrical circuit to the anodes 48. The electrodeposition current is therefore confined to the bus bars 35, angle members 45, anode supports 41, and anodes 48. The frame 31 carries a pair oflower supports formed from insulation material indicated at 50. Each of the supports 56 is provided with an engaging ledge like recess as shown more particularly in Fig. 14. The frame 52 for carrying articlesto be plated is shown in detail in Figs. 15-20. Frame 52 is stifi'ened by a horizontally extending interconnecting member 54'. Frame 52 and member 54 are formed from metal having low electrical resistivity and high conductivity, such as copper. The frame 52 and member 54 are covered with insulation material indicated generally at 53 in Fig. 20 so that there is minimum exposure of the frame or member 54 with respect to the plating bath when the frame is immersed in the bath. The frame 52 carries a pair of trunnion members 55 adjacent the lower edge thereof for engaging the ledge like recesses 5| in the insulated lower supports 50 when the frame 52 is mounted in position adjacent anodes 48 on frame 31. Frame 52 is provided with a pair of symmetrically arranged hook shaped suspension members and negative bus connectors 56. The suspension and negative bus connectors 56 are. electrically and mechanically connected to Frame 52 carries a plurality of article engaging members, certain of which I have indicated at 58 and others of which I have-shown at 59. When the apparatus of my invention is used in chromiumplating, the article engaging members 58 and 59, may be formed from nickel or metal which is not attacked in the electroplating bath in which the articles to be plated are immersed. The article engaging members 58 and 59 are directly secured to the metallic parts of the frame 52 and laterally extending member 54 before the insulated covering 53 is applied to the frame 52 and member 54. I have shown the article engaging member 59 suitably slotted to embrace opposite sides of the metallic strip constituting frame 52 with rivet .60 passing through article engaging member 59 and the metallic strip of the frame for establishing a good electrical and mechanical connection.

Each of the article engaging members 59 is provided with a socket 59a as shown more particularly in Fig. 19 into which the renewable article adjustable set screw for securing the renewablearticle engagingmember 6| in a selected position in socket 59a according to the mannerin which the articles carried by frame52 aremount. ed with respect to the frame. Each of the article engaging members 6| are notched on the end thereof as indicated at 63 forengagingthe articles to be plated.

In Fig. 6 I have shown on an enlarged scale, the manner of mounting kitchen or table utensil covers 64 in position on frame 52 for purposes of plating. I have indicated the articles 64 as havber 13 projecting in opposite directions.

at least two of the spaced article engaging members 6|, the article 64 being resiliently pressed into engagement with notches 63, in at least two of the members 6| by means of the resilient article engaging members 58. It will be understood that the process of my invention is applicable to many kinds of articles of a variety of shapes and sizes and that various lengths of renewable article engaging members 6| may be employed in the sockets 59a of the article engaging members 59 to coact with the resilient article.

31 and allowing the notched latches of the insulation material 66 to engage the upper edge of the frame 52. Frame 52 is thus maintained in parallel spaced relation with respect to frame 31 and insulated therefrom with the articles 64 carried thereby centered in spaced relation to an- 'odes 48 but spaced and insulated therefrom. The

notched latches 66 arepivoted at 61 on. frame 31 and are formed from insulation material so that there is no tendency for the passage of the elec-,

trodeposition current between frame 52 and frame 31.

In a position adjacent the top of tank I and ,located adjacent one side thereof, I provide a support indicated generally at 68 which carries a pair of spaced journal members 69 in which shaft 10 is journaled for angular movement.

Shaft 10 carries switch arm 1| which is movable.

through an acute angle to establish-connection with fixed contact or switch jaws 14 for closing an electrical circuit through the negative bus bar 15. Shaft 19 also carries a pair of lever arms in the nature of bell crank extensions 12. Each of the lever arms 12 carry a terminal mem- The arrangement of the lever arm 12 with respect to shaft 16 is' entirely symmetrical and the assembly is counterbalanced in movement by means of a counterbalanced guide rod 16 extendingthrough shaft 10 on an obtuse angle with respect to the lever arms 12. .Theguide rod 16 carries an adjustable counterweight 11 thereon having a suitable set screw 11a for fixing the counterweight in selected position on'the guide rod 16. There is an insulated stop 18 disposed between each of the lever arms 12 and the adjacent positive bus bar 1 to limit the downward movement of lever arm 12 and prevent contact between the lever arm 12 and the positive bus bar 1 when the'lever arms age in the lowermost position, illustrated in Fig. 1

The positive bus bar'1 provides supports for the spaced anodes 19 which depend by'means of contact hooks 80 from the positive bus bar 1.

In the operation of the electrical plating apparatus of my invention, a-milltiplicity of racks 52 may beemployed and thearticles to be plated may be assembled on the-racks preparatory to the plating operation. It is only necessaryfor an operative to pick up the relatively light weight rack with the articles secured in position thereon and mount the rack with respect to the frame 31 when the frame is iii-elevated position, shown in Fig. 9, counterbalanced by weight 33. The operative rests the trunnions 55 on frame 52 in the ledge like recesses 5| of the insulated lower supports 50 of frame 31 and moves the frame 52 toward frame 31 to a position where the notches of the insulated latches 66 engage the upper edge of frame 52 whereupon frame 52 and the articles to be plated-are secured in position in spaced relation to the frame 31 and anodes 48. Because of the normal bias force of switch 1|, due to adjustable counterweight 11, lever arms 12 are maintained out of the path of frame 31 as il-' lustrated in Fig. 9 allowing the operative adequate space by which to introduce frame 31 and the articles to be plated into the electroplating bath without accidentally touching either the positive or negative buses or terminals. The operative applies a slight manual force against frame 31 for causing the frame to move into the electroplating bath. The frame descends against the restraint offered by the counterweight 33. When the frame 31 descends to a position substantially level with the negative bus terminals 13 carried by lever arm 12, the operative swings the frame 31 slightly to the rear engaging hook shaped suspension members and negative bus conductors 56 over the negative terminal members 13. downward force to frame'31 reaching a position of descent similar to that illustrated in Fig. 2. When this position is reached, rotary member 24 has arrived at a position where the eccentric cam portion 26 commences to act as a lever arm rapidly into the electroplating bath. The articles to be platedare thus immersed and immediately upon complete immersion, switch arm H establishes connection with contact 14 closing the circuit from negative bus 15 through contact 14, switch arm 1|, shaft 10, lever arms 12, terminals 13, hook shaped suspension members 56, frame 52, to the articles to be plated 64- as cathodes. The path of the electrodeposition current through the bath passes from the cathodes 64 to the anodes 48 and 19. A path of return from anode 19 includes hook supports 80, positive bus bars '1, and positive connecting bus ID to the common positive return l5 to the potential source. The path from anodes 48 extends through supports 41, angle members 45, positive bus bar connections 35, connections 36 to horizontal bar l9, foldable, extensible and retractible frame l6 through positive depending frame I6 through positive depending buses I 4 through the common return conductor l5.

- After the plating operation, the operative ele vates frame 31 as indicated in Fig. 2 and as the articles to be plated are about to leave the plating bath, switch arm 1| moves away from contact 14 opening the electrodeposition current circuit through negative bus 15. The operative continues to raise frame 31. Lever arms 12 swing in a predetermined are by virtue of the normal bias applied by counterbalance 11 on the counterbalanced guide rod 15. The operative swings frame 31 slightly forward freeing the hook shaped suspension members and negative bus conductors 56 from terminal members 13. At this position of elevation, counterweight 33 has reached a position of complete counterbalance of loaded frame 31 as illustrated in Fig. 2 and the operative with very little effort shifts the The operative continues to apply a.

retractible frame It upwardly to the position illustrated in Fig. 3. During this process, the lever arm originally afforded by the distance between the journal-of rotary member 24 and the connection 28 of the cam has effectively reduced to the diameter of the cylindrical portion 21 so that counterweight 33 more than overbalances the mass of frame 31. The frame 31 is elevated until abutting face 30 of eccentric cam portion 26 abuts against abutment stop 3| on overhead frame H as illustrated in Fig. 3. The operative now slightly raises insulated latches 66 releasing the upper edge of frame 52. Frame 52 is then shifted at a slight angle on trunnions 55 and the frame carrying the plated work quickly reide ,film. The work of the operatives is vastly speeded up with the apparatus of my invention as the carrier may be loaded and unloaded rapidly and there is no loss of time in the cutting on of the electrodeposition current circuit as soon as the articles to be plated are submerged. The

-fact.that the operatives may disregard entirely the electrical operation of the plating bath either to cut on the current or cut off the current allows the operatives to give full attention to loading and unloading and the mounting and renewal of the ware with respect to the frame. The variation in rate of movement of the elevator affords an automatic timing for the entire equipment which facilitates the electroplating operation.

Because of the fact that the article engaging members 58--59--6l are formed from nickel or Monel metal or other material not subject to attack by chrome acid, the article supporting means functions particularly well in a chromium plating bath.

While I have described my invention in certain of its preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. Electroplating apparatus comprising a tank for an electroplating bath, a switch pivotally mounted adjacent the top of the tank, a lever arm connected with said switch and projectible to a substantially central position over said tank, a frame, means for raising and lowering said frame with respect to said tank, a separate article carrying frame detachably connected with the aforementioned frame and a member extending from said article carrying frame and engageable with said lever arm for closing s'aid switch when said frames are lowered to-a position for immersing articles in the electroplating bath.

2. Electroplating apparatus comprising a tank for an electroplating bath, a shaft member journaled adjacent one side of said tank, a pair of arms carried by said shaft member and movable to a position centrally over said tank, a terminal member disposed adjacent the extremity of each of said arms, a switch blade carried by said shaft, a contact aligned with said switch blade and a rack carrying articles to be plated having hook members engageable with. the terminal members on said arms as said rack is lowered into said tank for moving said switch blade to a position" establishing electrical connection with said contact.

3. Electroplating apparatus comprising'a tank for an electroplating bath, a shaft member Join- :a rack carrying articles to be plated having hook members engageable with the terminal members on.said arms assaid rack is lowered into said tank for moving said switch blade to a position establishing electrical connection with said contact, and means for normally biasing said switch blade to open position with respect to said contact.

4. In an electroplating'apparatus; a tank con taining an electroplating bath, an article carrier for immersing and removing articles with respect to said electroplating bath, means for projecting and retracting said article carrier with respect to said electroplating-bath comprising a rotary member including an eccentric cam portion and a drum portion; cables connecting said eccentric cam portion .and said article carrier in predetermined operative relationwith respect to the level of said bath, and a belt connected at one end to said drum and to a counterweight at the other end, whereby a differentially effective elevating force is applied to said article carrier according "to. the-position thereof with respect to the level of the bath in said tank.

5. Electroplating apparatus comprising a frame immersible in an electroplating bath, a

. multiplicity of anodes mechanically supported by said frame but electrically insulated therefrom and electrically bonded together, an article carrying frame, insulated socket and latch means for detachably mounting said article carrying frame withmespect to. said immersible frame, and means for establishing electrical connection with articles carried by said article carrying A frame as cathodes in the electroplating bath.

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