US2133324A

US2133324A - Barrel plating apparatus

Info

Publication number: US2133324A
Application number: US28064A
Authority: US
Inventors: John M Hosdowich
Original assignee: United Chromium Inc
Current assignee: United Chromium Inc
Priority date: 1935-06-24
Filing date: 1935-06-24
Publication date: 1938-10-18
Anticipated expiration: 1955-10-18

Description

1938. J. M. HOSDOWICH 2,

BARREL PLAT ING APPARATUS Filed June 24 1935- I 2 Sheets-Sheet l E a lNVENTO JOHN M. HOSDOWICH.

ATT RNEY 1938- J. M. 'HOSDOWICH ,3

BARREL FLATING APPARATUS Filed June 24, 1955 2 Sheets-Sheet 2 ;imi j 6 a v i| III- I I d 1% I23 MINVENTOR L5 1 w V JOHN MHOSDOWICH.

Patented Oct. 18, 1938 BARREL PLATING APPARATUS John M. Hosdowlch, Waterbury, Conn., assignor to United Chromium, Incorporated, New York,

N. Y., a corporation of Delaware Application June 24,1935, Serial No. 28,064

12 Claims.

This invention relates to barrel plating apparatus and provides improvements therein.

Chromium plating in barrels is a matter to which much thought and attention has been given ever since chromium-plating became a practical art. The conditions for successful chromium plating in barrels are considerably more exacting thanfor ordinary tank plating. The principles for such successful chromium plat- Fink and Eash 1,899,679, dated February 28, 1933. The present invention provides improvements in the barrel-plating apparatus in the direction (a) of enabling the process of plating in barrels to be carried out on varieties of articles within a comparatively wide range, and-on mixtures of articles of different shapeand size, with only minor adjustments such as are readily made on the current and voltage and on the temperature; (b) of providing for varying the rate of feed-of articles to the barrel so that a. rate of feed best suited to the plating of the kind of article to be plated may be obtained; (0) of. providing a good and reliable current distribution within the apparatus and solution; (d) of providing a uniform temperature of the solution I of the apparatus.

An embodiment of the invention is illustrated in the accompanying drawings, wherein:

Fig. 1 is a top plan view of the apparatus, with parts broken away; I

Fig. 2 is a view partly in side elevation and Zfia iiirtlly in vertical section 01' the part shown in a.

Fig. 3 is a view partly in end elevation and partly in transverse vertical section; 1

Fig. 4 is a view in side elevation of the part of the mechanism for feeding articles to the barrel;

Fig. 5 is a transverse section of the parts shown in Fig. 4.

Fig. 6 is a fragmentary view, looking toward the inside face, of the rotating part of the feeding device shown in Figs. 4 and 5.

Referring to said drawings, numeral Ill designates a plating barrel; l2 designates a tank for containing a plating solution as a chromic aciding in barrels are set forth in thepatent to' and assembling and dis-assembling of the parts 1 acid radical plating solution, in which the barrel is partly immersed; ll designates a motor for'rotating the barrel l0 throughmeans hereinafter described; l6 designates a suitable means for feeding articles to be plated to the tank; i8 5 designates a means, as a coil, through which a medium for regulating the temperature of the plating solution in the tank may be circulated; and 20 and 21 designate respectively electrical leads to the anode and barrel (cathodic).

The barrel I0 is conducting is preferably perforated as indicated at 25, though it can also be made without perforations, and is constructed and operated in such a manner that the contents are intermittently tumbled while con- 15 tinuously immersed, as described in the patent to Fink and Eash 1,899,679 hereinbefore referred to. The barrel is rotated at a slow rate (as for example revolution per minute). The barrel in is provided on its inside with a spiral rib 21 which 20 acts to advance or feed the work, as the barrel is rotated, from its intake end (at the right in Figs. 1 and 2) to its discharge end (the left in said-figures). The rib 21 is preferably made of electrically insulating material highly resistant 25 to the'action of the chromic acid solution, the use of such a rib showing an exceptional saving. in the current used as compared with acon-. ducting rib. The material which is used for the 1 rib is a conjoint polymerization product of two 30 different vinyl compounds, as described in the ap-v plication of George K. Herzog, Serial No. 753,827, filed November 20, 1934. Means 29 such as cleats or corrugations may be provided on the ing a periodical or intermittent tumbling action of the articles within the rotating barrel during the plating operation which is carried on there-- in. The barrel is preferably made with end pieces 30, 3|, in as indicated at 33. The end pieces 30, 3| are preferably of a greater diameter than the barrel, and have portions 35 which extend outwardly beyond the diameter of the barrel. The portions 35 provide annular conducting rings extending 45 edgewise from the axis of the barrel, with which brushes 31, connected with the cathode leads 2], make sliding contact, and thereby conduct current to the barrel while it is being rotated.

To obtain a highly uniform conductance from the cathode lead 2i to the barrel, the brushes 31 are each formed of a plurality of superposed thin copper plates the ends of which are turned inward, so that the end of each plate bears on the terminal of the cathode lead 2| .and on the porinner surface of the barrel to aid in accomplish- 35 having large central openings there- 40 a bolt and nut shown at 38*.

covers the top of the tank l2.

ranged substantially in line with the horizontal tion 35 of the end-pieces 30 respectively as indicated at 38. The superposed plates are slotted, as indicated at 38, to provide fingers. The division of the brushes 31 provided by the superposed plates and by the slots through the superposed plates, provides a uniform area of contact between the brushes and the part 35 of the moving barrel. One brush 31 is provided on each side of the part 35, and the pair of brushes are pressed against the terminal of the cathode lead 2| and the portion 35 of the barrel by means passing through each brush intermediate its ends, as The currents which the brushes are required to transmit for chromium plating are unusually heavy and the arrangement described has been specially designed to transmit such heavy currents, and in a way to avoid arcing and fluctuation and also in a way to avoid the generation of sufficient heat to dry the chromlc acid plating solution which comes in contact therewith, such drying would cause sparking at the brushes, with consequent pitting of the part 31 with which the brushes Gear contact, and fluctuation of the current. teeth 33 are preferably cut on the portions 35 of the end plates 30, 3| so that these end plates may function as gear wheels through which the barrel is rotated, as hereinafter more fully described.

40 designates an anode, of a material such as usually used with chromic acid plating baths, which is constructed and arranged so as to be supported independently of the barrel, and also in such manner as to be removable through the openings 33 in the end pieces ofthe barrel. The anode comprises a bar 43, the ends of which are preferably offset and raised as indicated at 4| and 42. The ends 4|, 42 of the anode pass through the openings 33 in the end plates 30, 3| addacent the inner edges thereof, and rest on

bearings

44, 45, one of which, as the bearing 44, may be a terminal-clamp, to which the anode leads 3!) are connected, and through which current is conducted from the anode. The bearings or

clamps

44, 45, are outside of the barrel, and support the ends 4|, 42 of the anode rotatably,

so that when the barrel is not in use the anode maybe readily turned so to lift the unused parts out of the solution. The

bearings

44, 45 are preferably supported upon a cover 41 which partially The ends of the anode are out of the plating solution and also out of the spray which arises from the solution within the tank, and the offset arms 4|, 42, passing out through the openings close. to the inner edges of the end-pieces 30, 3| afford maximum clearance through the said openings 33 for the introduction and iemoval of articles to and from the barrel. The anode 40 also preferably comprises a plurality of spaced transverse discs or plates 49, which project from the bar 43 below the surface level of the plating solution in the tank. The discs are preferably perforated, as indicated at 48 to increase the anode-area. The number of the discs and the perforations therein thereby provide a large area of contact between the solution and the anode.

The barrel I is preferably rotatably supported in such manner as to be readily removable from the apparatus. To this end, it is preferably supported by a plurality oi rotating parts 50, 52, 53, above the solution level within the tank. The Parts 50 to 53 are preferably in the form of pinions which engage the teeth 39 on the end pieces The pinions 50-53 are preferably ardiameter of the barrel, at opposite sides of the barrel. The axis of the barrel is thereby well above the solution level of the tank. The openings 33 in the end pieces extend below the solution level, the greater part of the area of the openings however being above the solution level of the tank. In this way the solution level is made so high that the barrel, during its rotation, does not lift the articles on its inner circur'nference, high enough to carry them out of the solution before they tumble back into the' low part of the barrel. The pinions 50-53 are preferably fixed on shafts 55 running lengthwise of the tank alongside of the outer sides of the barrel above the solution level of the tank. The barrel may be removed, (after the anode 40 has been disengaged), by simply shifting it sideways and lifting it upwardly, to disengage the pinions from teeth 33 on the end pieces 30, 3|, and thereby release the barrel. The shafts 55, 56, may be rotatably connected with the motor through worm wheels 51, worms 58 on opposite ends of a cross shaft are worm 62 on the cross shaft, and a worm 53 on the shaft of motor l4. Boxes 65 project downwardly through the tank cover 41 and surround and protect the worms on

shafts

55 and 60,'and also the bearings of these shafts, from the solution and spray within the tank. Chromic acid plating solution oxidizes lubricating oils, and is itself an antilubricant. The boxes act to prevent the solution coming into contact with the bearings, worms and gears. These boxes also act as receptacles for preventing lubricant from the bearings, worms and gears falling into the plating solution.

Numeral 61 designates a collar on the tank cover 41, on which collar a flue may be connected, through which fumes and spray arising from the surface of the solution within the tank may be drawn off. The; cover 41 is spaced from the sides of the. tank asindicated at 59, and air entering th ough the space 69 is drawn across the upper part of the tank below the cover 41 and carries fumes and spray with it through the suction duct connected to the collar 61.

A cup which extends outwardly from the side of the tank, and communicates with the space within the tank, may be provided. The cup 10 is preferably provided with a lip 1|, over which the solution within the tank may flow. This lip 1| serves to regulate the solution level within the tank, and in practice the tank is kept filled to this level.

Numeral 80 designates a stirrer. This stirrer is located within the tank in such position as to create a circulation of the plating solution out of the end nearest the stirrer and in the othenend. In practice it is found highly desirable to maintain the. solution at a uniform temperature. In practice the temperature is regulated within a variation of 1-2 C. In barrel plating inwhich a conducting barrel is used, and particularly in chromium plating where relatively high current densities are employed, a comparatively large amount of heat is generated in the solution within the barrel. It is accordingly important to provide a positive circulation of the plating solution to and from the barrel. Such a circulation is provided by the described arrangement. The stirrer provides a circulation of the solution at a very even-temperature in at one end of thecylinder and out at the other. In a barrel which is perforated, the perforations 25. admit the solution along the length of the 30 stationary disc 90.

35 out having to change gears.

barrel, particularlyat the bottom side of the barrel where the plating current is concentrated.

High effectiveness of plating is favored by regulating the rate of feed of articles to the barrel,

the rate of feed being regulated on the basis of trial and experience, in accordance with the size and shape of the articles to be plated in the barrel. The feeding means I5 is constructed and arranged to provide for such a variation in the rate of feed of the articles.

The feeding mechanism I5 comprises a pair of hollow frustums 90, 9| mounted on an axle 32 mounted on a bracket 93. One of the frustums, as the frustum 90, is fixed upon the said axle 92,

and the other is rotatable upon said axle as indicated at 05. The

rim portions

96, 91 of the two frustums are fitted together very closely, so that the least amount ofvspace is left between the two rlm portions, and the entrance of very small articles, or of thin parts of articles, between said rim portions is minimized. The parts of the two frustums adjacent the rim portions are formed with steep sides I00, IOI so as to form an annular groove or pocket I02. Within the annular pocket I02 are arranged a plurality of scoops I05. These scoops I05 are shaped to the sides of the annular pocket or groove I02. The scoops I05 have tangs I01 which fit into grooves I00 mortised into't'he sides of the rim 35 of the The scoops I05 are removable. By varying the number of scoops I05 in use '(by removing one or more), and by varying the size of the scoops, the rate of feed of articles from the feeding mechanism may be varied with- The frustums and scoops are made of rustless material so as not to speck the work or contaminate the plating bath. Aluminum and stainless steelhave been used.

The rotatable hollow frustum 3| is conveniently 40 rotated at a regular speed, related to the speed of rotation of the barrel l0, by a suitable means. These means, as here .shown, comprise a gear wheel IIO fixed to the hollow frustum 3|, a pinion I I on a stub-shaft II3 having thereon a worm 5 H5 meshing with another worm II5 on a shaft 1, which latter shaft has thereon a gear II9 meshing with a worm II2 bn the aforesaid crossshaft 60 which drives the

shafts

55 and 55 which carry the pinions for rotating'the barrel I0. Numeral I20 designates an opening inthe side of the hollow frustum 00 through which articles to be fed to the barrel and plated, are placed in the feeding mechanism, and a mass of these articles is maintained in the space I22 within and 55 between the hollow frustums 30, 0|, which part of the feeding mechanism may be designated as v a hopper.

It has been found to contribute to successful platingto keep the articles wet, after they have 60 been cleaned and placed within the hopper I22,

until they are fed to the barrel. For this purpose a trough I 25 is provided, which trough is provided with an overflow pipe I21, and kept filled to the level of the top of the overflow pipe by liquid 65 (water) which is constantly supplied to the trough I25 through supply pipe I29. 'I'hehollow frustums 90 and SI extend'below the surface of the liquid in the trough I25 to such an extent that the hopper portion I22 is below the level of the liquid .70 in the trough I25.

A chute I projects into the upper part of the space between the hollow frustums 90;," through a suitable opening I32. The chute I30 is adjustable longitudinally within the said space between "15 the hollow frustums 30, 0|. For this purpose the plating tank.

chute I30 may be attached to a slotted arm I to which it may be fastened by means of a stud and clamp screw I35 which is adjustable in the slot in said arm I35. The chute I30 may also be turned on the stud I35 to adjust the position of its receiving-end with relation to the dumpingposition of the scoops I05.

The'chute I30 connects with another chute I31 which extends into the barrel l0 through the opening 33 at the front end, and delivers the articles to be plated to the front end of the barrel. The chute I30, like the frustums, is made of rustless material.

The scoops I05 attached to the rotatable frustums SIpick up acertain number of the articles from the hopper or space I22 between the hollow discs 90, 9|, at the lower part thereof, and lift these upwardly as the aforesaid frustum 9| rotates. When the scoops reach their upper position or thereabouts, the articles which have been carried up and retained by the scoops arev dumped into the chute, I30, and from thence slide down the chutes I30 and I3! into the barrel at its front end. As heretofore explained the rate of feed of the articles may be varied by varying the number of scoops I05 in use, and also the size of the scoops. The rate of feed may be further varied by adjusting the upper end of the chute I30 towardand from the dumping position of the scoops I05; by a rotative adjustment around the stud I36; and by a combined longitudinal and rotative adjustment. By removing the upper end of the chute !30 further from the dumping position or from the axis of the trajectory of the from each cfthe scoops will be caught by the chute I30, and vice versa.

Articles dumped into the front end of the barrel I0 will be advanced beneath the anode 4 0 to the rear end of the barrel, by the spiral rib 21 as the barrel I0 rotates. Themass of articles lying in the bottom part of the cathodic barrel between each spiral of the rib 21 will be acted on by the current and plated,- during which process the articles will be intermittently and repeatedly tumbled. When the plated articles reach the rear end of the barrel, they are caught in one or another of, a plurality of pockets I40, and raised in these pockets as the barrel rotates. The pock-' ets I40 are preferably insulated so as to be nonconducting. As the pockets reach the upper position within the barrel, the articles therein will be dumped, and as they are dumped they are caught by a chute I50 which projects into the barrel through the opening 33 in the end plate 3|, the articles falling on the chute I 50 being carried away, as to a wash tank and drying apparatus, as it is usual after articles are removed from a A description of the operation of the device has been ccirsbined with the description of the structure.

From the foregoing description it will be perceived thafthe invention provides a barrel plating apparatus in which all of the driving parts of the apparatus and the electrical connections are outside of the solution and to a large extent prothe solution within the barrel is efl'ectively prevented and a uniform temperature of the solution in the immediate vicinity oi the "articles being platedeffected, thereby, (and also bythe feed regulation) contributing materially to the capability of plating varieties of articles within a comparatively wide range, and mixtures of articles of diiferent kinds and shapes. 4

The invention may receive other embodiments than that herein specifically illustrated and described.

.What is claimed is:

1. Barrel plating apparatus, especially applicable for chromium plating from the chromic acid type of plating solution, comprising a tank for containing the plating solution at a predetermined solution level therein, a rotatable metallic barrel with which artioles'therein make electrical contact, having end-pieces with large central i openings through which objects may extend eccentrically into the barrel without meeting obstruction when the barrel is rotated, an anode within and extending longitudinally or said barrel, means comprising shafts and bearings for supporting said barrel at each side at or adjacent the sides of its horizontal axial plane, said horizontal axial plane being adjacent but above the solution level of the tank so that a large segment of the barrel may be immersed and said bearings are abovesaid solution level.

2. Barrel plating apparatus according to claim 1 further including shields interposed between said bearings and the space above said solution, to protect said bearings from spray from said solution.

3. Barrel plating apparatus according to claim 1, further including an anode extending longitudinally within said barrel and having offset ends extending through the openings at each end oi.

said barrel, said oifset ends lying adjacent the edges of the end-pieces of the barrel, so as to leave the central part of the openings in said endpieces clear. 1

4. Barrel plating apparatus according to claim 1, further including an anode extending longitudinally within said barrel and having oflset ends extending through the openings at each end of said barrel, said oflset ends lying adjacent the edges of the end-pieces oi the barrel, so as to leave the central. part of the openings in said endpieces clear,said anode further comprising a large number of transverse segments extending below the solution level 01' the tank, so as to provide an exceptionally large anode area for oxidizing compounds reduced from chromic acid which are formed in the plating solution during plating.

'5. Barrel plating apparatus according to claim 1, wherein said end pieces have portions extending outwardly beyond the diameter of the barrel,

and further comprising brushes making electrical contact with said outwardly extending portions of the end-pieces.

6. Barrel plating apparatus according to claim 1, wherein said end pieces have portions extending outwardly beyond the diameter of the barrel, and further comprising brushes making electrical contact with said outwardly extending portions of the end-pieces, said brushes being of a size and area to reduce heatingto such extent as not to dry thesolution on the brushes scraped from the end-pieces during rotation of the barrel.

7. Barrel plating apparatus according to claim 1, wherein said end-pieces have gear-teeth thereon, and wherein said means for supporting the barrel comprises shafts and gears thereon engaging the gear-teeth on said end-pieces at two sides or the barrel.

8. Barrel plating apparatus according to claim 1, further comprising a cover extending over the top of said tank and spaced from the tank at the sides, and wherein the bearings of said means for supporting the barrel are mounted on said cover at parts thereof out of communication with the air-space above the solution.

9. Barrel plating apparatus according to claim 1, further comprising a cover extending over the top of said tank and spaced from the tank at the sides, and wherein the bearings of said means for the barrel, said rib being of electrically insulating material, inert toward a chromic acid plating solution.

12. Barrel plating apparatus according to claim 1, further comprising a spiral rib and a pocket at the delivery end of said rib, said rib and pocket being on the inner face of said barrel, said rib acting to advance articles lengthwise of the barrel, and said pocket receiving said articles advanced by the rib and lifting them to s dumping position adjacent the top side of th barrel, said rib and pocket being electrically insulated.

gQHN M. HOSDOWICH.