US3674673A

US3674673A - Apparatus for electroplating workpieces

Info

Publication number: US3674673A
Application number: US9777A
Authority: US
Inventors: Richard J Jessup
Original assignee: Udylite Corp
Current assignee: OMI International Corp; Udylite Corp
Priority date: 1970-02-09
Filing date: 1970-02-09
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04
Also published as: FR2079316B1; BR7100168D0; ES387773A1; SE373606B; JPS53142525U; GB1331108A; JPS53117524U; BE761946A; JPS5731156Y2; DE2102458C3; DE2102458B2; CA922270A; DE2102458A1; NL7100761A; ZA708427B; FR2079316A1; JPS5731155Y2; US3803007A

Abstract

A treating barrel comprising a pair of spaced end members, a perforate body member extending between said end members and defining there between an internal, substantially cylindrical shaped zone for receiving articles to be treated. The body member is formed to define an opening therethrough which extends longitudinally between the end members and which has a width which is less than about one-sixteenth of the circumference of the cylindrically shaped zone. At least one tumbling rib, which extends along the interior surface of the body member between the end members is disposed substantially dimetrically opposite to the opening, the tumbling rib projecting radially inwardly of the interior surface of the body member into the zone and being designed to impart a cascading action to the articles in the barrel during oscillatory motion thereof. Means are provided on the end member for supporting the barrel for oscillatory movement about an axis which extends substantially longitudinally of the zone. The overall apparatus assembly includes a work carrier for supporting the treating barrel at a treating receptiacle, drive means for oscillating the barrel when the work carrier is operatively positioned at the treating receptacle and coacting stop means which are oriented relative to the opening in the barrel to normally limit the rotary movement of the barrel in both directions beyond an angularity at which the articles are discharged through the opening of the barrel.

Description

United States Patent 1151 3,674,673

lessup July 4, 1972 [54] APPARATUS FOR ELECTROPLATING WORKPIECES ABSTRACT 721 Inventor: Richard J. Jessup, Bloomfield Hills, Mich. A treating barrel compfl'sing a p of Spaced members, a

- perforate body member extending between said end members Asslgneel Udyme Corporation, warren, Mlchand defining there between an internal, substantially cylindri- 22 F d: F b. 9 197 v cal shaped zone for receiving articles to be treated. The body 1 e 0 member is formed to define an opening therethrough which [21] Appl. No.: 9,777 extends longitudinally between the end members and which has a width which is less than about one-sixteenth of the cir- 204/213 204/214 259/89 cumference ofthe cylindrically shaped zone. At least one tumbling rib, which extends along the interior surface of the body 51 1m. 01. ..C23b 5/78 d b 1 581 Field of Search ..134/157 R, l63-,204/2l3,214, member between the end members d'spose y dimetrically opposite to the opening, the tumbling rib project- 204/222; 259/81 89 ing radially inwardly of the interior surface of the body member into the zone and being designed to impart a cascadl kefelenceslclted ing action to the articles in the barrel during oscillatory motion thereof. Means are provided on the end member for sup- UNITED STATES PATENTS porting the barrel for oscillatory movement about an axis 2,956,943 10/1960 Hoegh ....204/213 which extends substantially longitudinally of the zone- The 3 479 271 11/4969 Sandrock" 2 4 2 overall apparatus assembly includes a work carrier for sup- 2,830,946 4/1958 Pleadwell ..204/214 Porting the treating barrel at a treating recepllacle, drive 1 means for oscillating the barrel when the work carrier is FOREIGN PATENTS 0R APPLICATIONS operatively positioned at the treating receptacle and coacting stop means which are oriented relative to the opening in the barrel to normally limit the rotary movement of the barrel in both directions beyond an angularity at which the articles are discharged through the opening of the barrel.

1,01 1,251 6/1952 France ..204/222 Primary Examiner--.lohn H. Mack Assistant Examiner-W. 1. Solomon Att0rneyStanlcy A. Lieberstein and William J. Schramm 13 Claims, 17 Drawing Figures go o 0 0 20 MW A.

PATENTEDJUL 41912 saw u or a P'A'TENTEDJIJL 4 1972 v 3, 674. 673

sum 8 or s APPARATUS FOR ELECTROPLATING WORKPIECES This invention relates to a novel horizontal treating barrel and more particularly it relates to a horizontal plating barrel which is designed and adapted to be oscillated rather than continuously rotated around its horizontal axis during normal plating operations. The invention further includes the overall apparatus assembly by means of which the oscillatory motion of this barrel is effected.

In the past, barrels have been extensively employed in industry for treating large quantities of small work pieces which cannot be economically and efficiently handled separately. Typically, the treatments to which the work pieces, contained in the barrels, have been subjected have included various cleaning, coating, and/or plating processes, in which the barrel has been immersed in a volume of the processing solution during treatment. In order to insure satisfactory contact of these processing solutions with the individual work pieces in the barrels, the barrels havebeen rotated while immersed in the processing solution, so as to impart a tumbling action to the work pieces. In order to insure that this tumbling action is imparted to the work pieces, the plating barrels used have generally been formed with a plurality of flat sides, these barrels typically being hexagonal in cross-section.

Although with this configuration of the barrel, the desired tumbling of the work pieces during rotation is effected, which tumbling cannot be achieved in a cylindrical barrel having a substantially circular cross section, the effective volume of such a barrel is appreciably reduced over that obtained with a cylindrical barrel of circular cross section having the same overall diameter. Additionally, because the prior barrels have been subjected to rotational movement within the processing solutions, it has been necessary to provide the opening through which the work pieces are loaded into the barrel with a securely fastened cover or door'so that the work pieces are not discharged into the processing solution during the rotation of the barrel. Not only are there appreciable maintenance costs for these doors or covers and their necessary fastenings but, additionally, because the covers must generally be manually fastened and unfastened, it has been difficult to fully automate the processes using these barrels.

It is, therefore, an object of the present invention to provide an improved horizontal treating barrel which is adapted to be oscillated rather than rotated around its horizontal axis during normal processing operation.

A further object of the present invention is to provide an improved treating barrel and apparatus assembly whereby the barrel is controllably oscillated around its horizontal axis during the normal processing operations and which may be adapted for fully automatic operation.

Another object of the present invention is to provide an improved process for treating quantities of small work pieces in a barrel, which process may be substantially completely automated.

These and other objects will become apparent to those skilled in the art from the description of the invention which follows.

In the drawings which are attached hereto and form a part hereof,

FIG. 1 is a perspective view of a plating barrel incorporating the preferred embodiments of the present invention:

FIG. 2 is a transverse vertical sectional view through the plating barrel shown in FIG. 1;

FIGS. 3 through 6 are transverse vertical sectional views of alternate modifications of the plating barrel as shown in FIG.

FIGS. 7 through 11 show various alternate-drive mechanisims which may be used with the present barrels;

FIG. 12 is a schematic representation of a processing line which includes the assemblies of the present invention;

FIGS. 13 and 14 are schematic representations of alternate treating stations which are usable in a processing line as shown in FIG. 12;

FIG. 15 is an elevational view of a barrel assembly of the present invention having a removable stop mechanism; and

FIG. 16 is an end view of the barrel shown in FIG. 15.

Pursuant to the above objects, the present invention includes a novel treating barrel which comprises a pair of spaced end members, a perforate body member extending between said end members and defining therebetween an internal substantially cylindrically shaped zone for receiving articles to be treated, said body member formed to define an opening therethrough extending longitudinally between said end members and being of a width less than about one-sixth of the circumference of said zone, and at least one tumbling rib extending along the interior surface of said body member between said end members and disposed substantially diametrically opposite to said opening, said tumbling rib projecting radially inwardly of said interior surface of said body member into said zone for imparting a cascading action to the articles in said barrel during oscillatory movement thereof, and means on said end members for supporting said barrel for oscillatory movement about an axis extending substantially longitudinally of said zone.

More specifically, the treating barrel of the present invention comprises a hollow, elongated body member, substantially circular in cross-secton, and two substantially flat end members disposed at each end of the body member to form an elongated, substantially cylindrically shaped zone for receiving articles to be treated. An elongated, coverless slot-like opening is provided in the body member which runs substantially the entire length thereof between the two end members. This opening desirably has a width which is not greater than about one-sixth of the circumference of the zone formed by the end members and the body member and preferably is about one-tenth to one-twentieth. The interior surface of the body member is provided with at least one longitudinal, raised projection or tumbling rib which extends into the enclosed zone, running substantially the entire length thereof and which is further disposed substantially opposite the elongated, slotlike opening in the body member. The tumbling rib preferably has substantially nonparallel sides which extend into the zone in a convergent direction and which form an angle with the body member which is desirably within the range of about 10 to 60 and preferably within the range of about 20 to 40. Preferably the barrel is formed with a single rib, the sides of which are substantially flat and converge within the zone to form a rib which is substantially triangular in cross section. The barrel is further adapted to be oscillated, rather than rotated, substantially around its horizontal axis during normal processing operation. Although the barrels of the present invention are particularly adapted for use in electroplating processes they may also be advantageously used in other processes, such as cleaning processes, painting processes, nonelectrolytic plating processes, as well as various other coating processes, and the like.

The overall apparatus assembly, for use with the novel barrels of the present invention, includes means for imparting the desired oscillating motion to the plating barrel. This means may include suitable reversable drive motors, reciprocating drive racks or rods, and the like, in combination with the necessary gearing and/or other connecting means for trans mitting the reciprocating motion to the plating barrel, so as to prevent full rotation of the barrel and discharge of articles therefrom during normal processing operations. Additionally, the assembly includes suitable stops, clutches, and/or switches, or similar mechanisims for synchronizing the oscillating motion of the barrel with the drive mechanism, so that the barrel does not oscillate to a point at which the contents are discharged, except during unloading, regardless of the initial position of the barrel in the apparatus. Means may further be provided in the assembly for overriding the stops which limit the amount of oscillatory motion of the barrel so that, where desired, full rotation of the barrel may be efiected, as for example, at an unloading station. A detailed description of the preferred embodiments of the overall apparatus assembly, as well as of the barrel itself, is set forth hereinafter with reference to the accompanying drawings.

In FIG. 1, there is shown a preferred embodiment of the present invention in which the barrel 1 is mounted in a suitable supporting frame comprised of the cross-beam 9 and the downwardly extending legs 11 secured thereto at their upper end. The barrel 1 is rotatedly mounted at the lower end portion of the legs 11. The supporting frame is further provided with a pair of outwardly extending arms 13, which are connected to the upper portion of the legs 11, which anns include lugs 15 which are adapted to coact with a suitable receiving fixture or saddle 17 mounted along the upper portion of a treating recepticle tank (not shown) for properly positioning the apparatus as it is placed in the treating receptacle. Electrical connections 19 are provided to the ends of the cathodes 21 which are disposed within the barrel and are also connected to the lugs 15 which, when disposed in contact with the receiving fixtures or saddles 17 can be electrified to provide the necessary current for electroplating of work pieces in the barrel. Alternatively, other suitable support means for the barrel assembly may be used, such as a support having only a single saddle on each side.

The barrel 1 is formed of a body member 3, and two end members and 7, secured to the body member to form an enclosed, elongated substantially cylindrically shaped zone for receiving articles to be processed. The

end members

5 and 7 may be secured to the body member in any suitable fashion, as for example, by means of adhesive, welding, fasteners such as screws, or the like. The body member 3 is formed with a coverless, elongated, slot-like opening 2, which runs substantially the entire length thereof, between the

end members

5 and 7. This opening provides the means whereby parts to be treated are introduced into and removed from the barrel. As has been previously noted, the width of this opening is desirably less than about one-sixth of the circumference of the zone formed by the end members and the body member and preferably is from about one-tenth to one-twentieth. Where the width of the opening is greater than this, it has been found that it is frequently difficult to oscillate the barrel enough, without discharging work pieces, to obtain the necessary amount of tumbling of the parts. With regard to the minimum width of the opening, this will be largely dependent on the size and type of parts to be processed so that in some instances, widths less than about one-twentieth of the circumference may be used. In general, however, in order to obtain the maximum benefits of improved solution interchange and increased path for electrical current flow, the width of the slot is desirably not less than about one-twentieth of the circumference.

The body member 3 is provided with a plurality of perforations or apertures 4 which communicate with the interior of the zone or chamber to facilitate the passage of electrical current and/or the circulation of treating solutions into and out of the barrel. The size of each of these perforations or apertures will be limited to a size which is smaller than the size of the work pieces being treated in the barrel. Additionally, the relative spacing between the adjacent perforations or apertures will be restricted by the relative strength of the material from which the body member 3 is constructed.

In this latter regard, it is to be appreciated that various materials of construction may be used for the barrels of the present invention, depending upon the type of process in which the barrel is to be used. Where the barrels are to be used in an electro process, such as electroplating, they are desirably made of an electrically non-conductive material, such as synthetic or natural hard rubbers, polyvinyl chloride resins, polymethyl methacrylate resins, phenol formaldehyde resins, polypropylene, and the like. Additionally, of course, where the barrels are to be used in non-electrolytic processes, they may be constructed of metal, In any event, a wide variety of materials of construction may be used for the barrels, the only restriction being that the particular material utilized have the desired strength, resistance to corrosion and electrical properties for the particular process in which the barrel is to be used.

It is to be further appreciated that when the barrels of the present invention are to be used in electroplating processes, the electrification of the pieces contained in the barrel may be effected by means of flexible electrodes or cathodes 21, which extend into the interior of the barrels. Desirably, the flexible cathodes 21 are brought into the barrel through the

end walls

5 and 6 of the barrel, as in conventional rotatable, horizontal plating barrels, as shown in FIG. 1. Alternatively, however, such electrodes may pass through the slot-like opening 2.

As is shown in FIG. 2, the barrel of the present invention is formed with at least one raised projection or tumbling rib 6, which is disposed substantially opposite to the slotlike opening 2 in the body member 3. This tumbling rib projects into the material receiving zone of the barrel and extends substantially the entire length thereof. This projection or tumbling rib acts to lift the parts and cascade or tumble them as the barrel is oscillated, thereby assuring that the parts are constantly and evenly turned over as the barrel is operated. It has been found that the size and configuration of the tumbling ribs must be such as to allow the parts being treated to slide off of the rib and tumble within the barrel when it is rotated to its extreme position. Typically, the size of the angle which the sides of the rumbling rib make with the body member is desirably within the range of about 10 to 60.

This tumbling rib is preferably formed as an integral part of the body member 3, desirably by indenting the body member inwardly substantially opposite the slot-like opening, to form an elongated ridge, The apex of this ridge is disposed within the barrel or treating zone and the sides of the ridge form an angle with the body member which is within the range set forth above and preferably within the range of about 20 to 40. Although, this angle might more correctly be described as the angle the sides of the rib make with the tangent to the body member, for convenience reference hereinafter will be made to the angle between the sides of the rib and the body member.

In addition to the preferred configuration of the present barrels, as shown in FIGS. 2, other alternative configurations for achieving the same result are also possible, as indicated in FIGS. 3 through 6. As is shown in FIG. 3, rather than forming the tumbling rib as an integral part of the body member, the tumbling rib 6 may be a separate member which is secured to the body member 3, disposed opposite the slotlike opening 2 in the body member. As is shown in FIG. 4, the body member 3 may be formed so as to have more than one tumbling rib 6, which ribs are again disposed substantially opposite to the opening 2. As shown in FIG. 5, a lip member 8 may be added to the slot like opening 2, which lip member is found in some instances to aid in the loading and unloading of the barrel. Additionally, as shown in FIG. 6, the tumbling rib may be in the form of a substantially fiat side. It is to be appreciated that the lip member 8 may be used on any of the barrel configurations and that in addition to aiding in the loading and unloading of the barrel also helps retain parts in the barrel during treatment and acts to stiffen or strengthen the barrel as well. This lip may be substantially straight, as in FIG. 5 or curved, as in FIG. 6 and extends downwardly into the treating zone to a point which is substantially opposite the other edge of the slot-like opening. The specific length and curvature of this lip may vary so long as the opening between the edge of the lip and the edge of the slot is sufficient to effect the desired loading and unloading of the barrel.

It is to be further appreciated that in addition to the longitudinal tumbling ribs which have been shown in FIGS. 2 through 6, if desired, circumferential ribs or corrugations may also be provided in the body of the plating barrel. Moreover, if it is desired to use the barrels of the present invention for the simultaneous treatment of small loads of different types of parts, one or more partitions along the length of the barrel may be provided so as to divide the barrel into separate compartments. Additionally, the configuration of the barrel may be further modified to provide a plurality of ribs formed over the entire body member and the shape of the body member may also be modified so that it is not completely circular. It is believed that further modifications, to accomplish substantially the same results, can be made to the shape of the plating barrels of the present invention and that these modifications will be apparent to those in the art.

It is to be appreciated that when the barrels of the present invention are used in electroplating processes, the barrel is placed in a plating tank which contains a plurality of anodes, positioned so as to at least partially surround the barrel, in a known manner as with conventional rotating barrels. Alternatively, however, with the barrels of the present invention, eitherin addition to or in place of these conventional external anodes, an internal anode may be used. Such anode may be mounted in any suitable manner so as to dispose the anode through the coverless slot-like opening in the barrel and position it in the desired manner inside the barrel. In this manner, the internal anode may be used, either in place of, but preferably as a supplement to the conventional external anodes, thus making it possible to carry out various plating processes in the barrel, which have not heretofore been possible.

As has been indicated, the barrel of the present invention is adapted to be oscillated, rather than rotated, during normal processing operations. In a preferred embodiment, as is shown in FIG. 1, this oscillation is effected by means of a gear 10, mounted on the end member 7 of the barrel, and the gear train 12 mounted on one of the downwardly extending legs 11 of the barrel support frame. These are driven by the drive gear 16 on the motor 18, through the override clutch and gear mechanism 14. Desirably, the clutch and gear mechanism 14 is mounted on the barrel carrier frame while the motor 18 is preferably positioned at the treating station, being mounted on the treating recepticle. These components are positioned so that when the lugs 15 are properly engaged by receiver saddles 17, the drive gear 16 on the motor 18 will then engage the gears on the override clutch 14. The motor 18 is preferably a reversable electric or hydraulic motor which, during normal processing operations, will be periodically reversed so as to impart the desired oscillating motion to the barrel. This periodic reversal of the motor may be effected using any suitable control.

As is shown in FIGS. 15 and 16, the barrel 1 may be provided with a pair of stop blocks 20, which blocks will engage the stop plate 22 when it is in its processing position (1) as shown in FIG. 15. The stop blocks 20 are positioned on the barrel, with respect to the stop plate 22 so as to define the desired limits of the oscillating motion of the barrel. Thus, as the barrel is rotated in one direction by means of the motor 18, through the drive gear 16, clutch mechanism 14, gear train 12 and the gear 10, it will rotate until the block 20 on the barrel engages the plate 22 on the frame. At this point, the override clutch and gear mechanism 14 will slip or override and the motor 18 is reversed, by means of suitable control switches and/or pressure sensing means, thus reversing the motion of the barrel. Desirably, the stop plate 22 is spring loaded so as to hold it in its normal processing position (1). When it is desired to fully rotate the barrel, as for example in an unloading operation, the stop plate 22 may be either manually or automatically moved to the unload position (2), so that it is no longer engaged by the stop blocks 20 on the barrel. As is shown in FIG. 15 and 16, an unloading cam 26 may be pro vided at the unload station, which cam will engage tabs 24 on the stop plate 22, raising it to the unload position (2) thus permitting the barrel to be fully rotated. It is to be appreciated that the engaging plate or stop may also be mounted in the treating tank, rather than on the support frame.

Alternative configurations for the oscillating motion drive mechanisim of the overall apparatus of the present invention are shown in FIG. 7 through 11. In FIGS. 70 and 7b there is shown a plating barrel of the present invention having a gear mounted on the end wall 7 of the barrel 1 and a gear train 12 mounted on the downwardly extending leg 11 of the barrel carrier frame. The uppermost gear of the gear train 12 is mounted on a shaft 25, which shaft is rotatedly mounted on the crossbeam 9 of the frame. A drive arm 27 is provided on the shaft 25 and is pushed by the contact member 31 on the reciprocating bar 29. The reciprocating motion of the bar 29 is effected by means of the motor 33, crank arm 35 and the crank link 37. As the bar 29 reciprocates, the contact member 31 pushes the arm 27 in one direction, causing it to rotate and thereby effect the rotation of barrel in one direction, until the member 31 has raised the arm 27 to the point that it is no longer in contact with it. Thereafier, as the bar 29 is moved in the opposite direction, the contact member 31 again contacts the drive member 27 moving it and the barrel in the opposite direction until it has been raised to the point that there is no longer contacted by member 31. Thus, the amount of oscillation of the barrel is determined by coordinating the length of the drive arm 27 and the contact member 31. If desired, a spring type stop may be provided at the extreme positions of the drive arm 27 to move it slightly downward to insure that it will be in position to again be contacted by the member 31.

A similar type of drive mechanism is shown in FIG. 8 except that the barrel is provided with only the gear 10 which is driven by the partial gear 39. As in the previous configuration, a shafl 25 is operably connected to the partial gear 39, which shaft is driven by means of the drive arm 27, in the same manner as the apparatus shown in FIG. 7B.

In yet another alternate embodiment of the driving mechanism for the overall apparatus assembly of the present invention, as is shown in FIGS. 9 and 10, the barrel may be provided with a pivoted drive arm 45 which fits into a sloted drive head 47. When oscillating motion is imparted to the drive head 47 and the pivoted drive arm 45 is properly seated in the slot of the drive head, the desired oscillatory motion is imparted to the barrel. The oscillation of the drive head 47 may be eflected using any convenient means, such as a reciprocating rack, a drive arm and reciprocating bar, or it may be driven by a reversable electric or hydraulic motor, either directly or through a slipping or overriding clutch mechanism, as has been heretofore indicated.

Still another alternate embodiment of the drive mechanism which may be used in the overall apparatus assembly of the present invention is shown in FIG. 11. In this embodiment, there is provided a rack 41 and pinion 43 which drive a gear train 39 to effect the oscillation of the barrel, through the gear 10. The rack 41 is driven by means of the motor 33 through the connecting arm 35 and connecting link 37. As a further alternative, a partial gear may be substituted for the straight rack 41.

It is to be appreciated, that the various drive mechanisms which have been shown for use in the overall apparatus assembly with the present plating barrel are merely exemplary of the mechanism which may be used. Accordingly, it is believed that those in the art will realize that modifications of the assembly may be made and that further alternative mechanisms, which will accomplish the same results, may also be satisfactorily used.

In this regard, it is to be noted that an important feature of the overall apparatus assembly of the present invention is the means for limiting the amount of oscillation of the barrel during normal processing operations, such as an electroplating operation. These mechanisms may be formed as a part of the barrel itself, as with the stop members as shown in FIGS. 15 and 16, or they may also be a part of the drive mechanism itself, as with the reciprocating bar type of mechanisms as shown in FIGS. 7 through 10. In general, it has been found to be preferably to have these mechanisms limit the amount of movement or oscillation of the barrel so that it is not substantially in excess of about 180". By this, it is meant that when the barrel is positioned so that the slot-like opening is in substantially the full upright position, the movement of the barrel in either direction is not substantially greater than about The need for limiting the amount of oscillation of the barrel is to prevent the discharge or spilling of the parts being treated out of the barrel during the processing operation. Accordingly, it will be appreciated that in some instances, de-

pending upon the size and type of the load in the barrel, oscillation of the barrel in an amount greater than 180, e.g., 200 to 220, may be effected without the discharge of the parts. In general, however, this may require that the barrel be loaded to less than its nonnal capacity, i.e., less than about two-fifths full, which operation may not be economical and hence may not be desired. It is for this reason that it is generally preferred that the amount of oscillation of the barrel is restricted so that it is not substantially in excess of about 180.

Another important feature of the overall assembly apparatus of the present invention is the provision for means of synchronizing the oscillating movement of the barrel with the oscillating drive mechanism so that, regardless of the position in which the barrel is placed in the drive mechanism, the barrel will not be oscillated to a point at which the parts being treated will be discharged into the treating tank, during the normal processing operation. Such features are incorporated in the various driving mechanisms and barrel configurations as have been described hereinabove. For example, in the drive mechanism as shown in FIGS. 7 through 10, by the proper corelation of the size of the pushing member 31 and the drive arm 27, to obtain the desired amount of oscillation of the barrel, regardless of the position in which the barrel is placed, the reciprocating bar 29 and pusher member 31 cannot cause the barrel to rotate to a point at which the contents will be discharged into the treating tank. Similarly, with the mechanism shown in FIGS. and 16, by the proper combination of the positive stop members on the barrel and the slipping or overriding clutch mechanism, the same results are achieved. Additionally, even where a simple rack and gear drive is used with a reversible motor, by providing a suitable switch and electrical contact mechanism at the point of the maximum amount of oscillation of the barrel, this will effect the reversal of the motor causing the barrel to oscillate in the opposite direction, rather than being fully rotated.

Additionally, in the structure as shown in FIGS. 9 and 10, by means of the configuration of the slot in the drive head, until this head has rotated to the point that the pivoted drive arm 45 is properly seated in the slot, the barrel will not be oscillated and once the oscillatory motion of the barrel is such that the positive stop members are engaged, further oscillation in that direction will be prevented and the oscillating motion will then be reversed.

Moreover, as another important feature of the overall apparatus assembly of the present invention, it is desirable that the barrels be capable of being fully rotated when they are to be unloaded. Where the barrels are provided with positive stop members, as in the configuration shown in FIGS. 15 and 16, this may be accomplished by having these stops spring loaded, as shown in these figures, so that they may be manually or automatically moved out of position when the barrel is put into an unloading station. In general, it has been found that this unloading may conveniently be accomplished by using the conventional rotary drives as are commonly used with conventional rotating horizontal barrels. This unloading operation may involve rotating only the barrel itself or, if desired, may involve the rotation of the entire barrel assembly or super-structure, as by rotating the superstructure 90 and then oscillating the barrel to unload it. I

In the operation of the apparatus of the present invention, as is shown schematically in FIG. 12, the barrel 77 of present invention, including its superstructure 75 is supported by a suitable hoist member 73. This hoist member may either be manually or automatically operated. This assembly is transported by a suitable conveyor 71 through a load station 61 wherein the parts to be treated are loaded into the barrel from a movable hopper 69. The barrel assembly is then moved to a treating station 63 wherein it is lowered into a treating tank 79, as for example, a tank for electroplating. At this treating station, within the treating tank, the barrel is oscillated by means of a suitable oscillation effecting mechanism, such as has been described heretofore. After a suitable time in the treating station, the assembly is then moved to an unloading station 65 wherein the barrel is completely rotated so as to empty the treated parts into a receiving hopper 81.

It is to be appreciated that although only a single treating zone or station 63 has been shown, in a typical processing line, multiple treating stations may be present, at which the desired cleaning, pretreating and the like operations, as well as multiple plating operations, may be carried out. With this apparatus of the present invention, it is seen that the entire treating process for small parts in a treating barrel may be fully automated, thus eliminating the manual labor which is presently necessary, particularly in the loading and unloading portions of the processes which use conventional rotating horizontal barrels.

It is to be further appreciated, as is shown in FIG. 13, that the loading and unloading of the barrel may be accomplished in a single station. In this embodiment, the barrel assembly is brought into the station and is loaded by means of a suitable hopper. The loaded barrel is then transported through the various treating stations in which the desired processing of the work is effected. When the processing has been completed, the barrel is returned to the first station, shown in FIG. 13, wherein the barrel is rotated to discharge the load onto a suitable hopper or other conveying means. After the barrel has been unloaded, it is returned to a load position so that it can again be loaded by means of the hopper. Although the barrels of the present invention are particularly adapted for carrying out this operation in a fully automated system, these operations may also be carried out in a system which is at least partially manually operated.

As is shown in FIG. 14, the treating stations through which the barrel is passed may include a station in which the load in the barrel is subjected to various treating sprays and/or a station in which drying of the load is effected. In such a station, because of the coverless configuration of the barrel, the desired treating spray or drying gas, such as hot air, is injected through the open mouth of the barrel as it is oscillated in the station. The barrel is placed either automatically or manually, in the desired spray or drying station and oscillated. Hot air for drying or liquid sprays for various cleaning or rinsing treatments are then directed into the coverless slot-like opening of the barrel so that as the load is tumbled, all parts thereof are contacted with the spray or drying air. Additionally, in a treating station in which the barrel is submerged in the treating solution, nonles may be provided to pump or inject solution into the open mouth of the barrel as it is oscillated.

It is further found that with the plating barrel and overall apparatus assembly of the present invention, there is considerably flexibility of operation which has not heretofore been possible with barrels of the horizontal rotating type. Thus, for example, both the rate and degree of oscillation of the barrels of the present invention may be easily controlled by means of suitable timing devices and by adjustment of the oscillation mechanism so that a change in amount and degree of tumbling of the parts being treated is obtained. Additionally, by use of one or more partitions in the barrels, mixed loads of different types of parts may be treated at the same time.

The plating barrels of the present invention are found to provide further advantages over the conventional rotating horizontal barrels, in that by having a slot-like opening rather than a door, which is essential for the rotating barrels, there can be more interchange of solution in the barrels when they are submerged, and in electroplating processes, there is more path for current flow. Additionally, the open mouth in the barrel allows for the pumping of solutions or gases into the barrel if this is desired in the particular processing operation. The absence of doors and their necessary clamps or fastenings, also results in less solution dragout. The substantially circular cylindrical shape of the barrel also is advantageous over the convention hexagonal shaped rotating barrels in that the cylindrical shape provides for greater surface area for perforations for the passage of current and the interchange of solution and greater spreading of the load can be achieved. Additionally,

for the same size barrel, larger volumes can be treated and the substantially cylindrical shape provides both strength for carrying heavy loads and lends itself to having a substantially one piece construction for the main body of the barrel, thus adding simplicity and economy to the overall barrel construction. It has also been found that there is substantially less wear of the cathodes in the present barrels as compared to that encountered in conventional rotating barrels.

In addition to the apparatus which has been described above, the present invention also includes an improved method for electroplating articles in bulk. In this process, the articles to be plated are placed in a coverless, open mouthed plating barrel. The barrel has electrode means disposed therein, in contact with the articles to be plated. The barrel is immersed in an electroplating solution so that anodes are disposed around the exterior of the barrel when it is thus immersed. The barrel is then oscillated through an angle which is not in excess of about 220 and preferably is not substantially in excess of about 180.

As the barrel is oscillated, the articles contained therein are tumbled so that fresh or diflerent surfaces are continually exposed for electroplating. Additionally, electric current is directed into the barrel through the open mouth thereof, as well as through the conventional apertures or perforations which are formed in the barrel side walls. Similarly, fresh plating solution is continually drawn into the barrel through the open mouth, as well as the perforations, and a turbulent flow of this solution within the barrel is established. In this manner, all surfaces of the workpieces in the barrel are continually exposed to fresh plating solution and to more electric current than has heretofore been possible so that improved plating results are obtained in shorter periods of time.

As has been previously described, the desired tumbling and turning over of the workpieces may be accomplished by providing the plating barrel with suitable tumbling ribs. Additionally, this plating process may be carried out as a part of an overall treating process in which the processing of the parts from loading of the barrel, through the various treating stages of cleaning, rinsing, plating, coating and/or drying, to unloading of the barrel may be effected substantially automatically.

Although there have been described various embodiments of the invention, the methods and structures described are not to be taken as a limitation on the invention but merely as being exemplary thereof.

What is claimed is:

1. An apparatus for treating articles in bulk comprising a framework and a treating barrel supported thereby, said treating barrel including a pair of spaced end members and a perforated body member extending between said end members and defining an internal cylindrically shaped treating zone, said body member formed with a longitudinally extending opening of a width less than about one-sixth the circumference of said zone and at least one tumbling rib disposed in the interior of said zone substantially opposite to said opening, means on said end members for supporting said barrel on said framework for rotation about an axis extending substantially longitudinally and centrally of said zone, and coacting stop means on said barrel and said framework selectively positionable in an operative position for restricting angular rotation of said barrel and an inoperative position enabling unrestricted rotation of said barrel in either direction, said stop means oriented relative to said opening in said barrel to limit rotary movement thereof when disposed in said operative position in either direction between an angularity of at least about 180 up to an angularity below that at which articles are discharged from said opening.

2. The apparatus as claimed in claim 1 wherein the coacting stop means include a pair of stop blocks fixedly mounted on one of the end members of said barrel and an engaging member movably mounted on the framework supporting said barrel and selectively positionable in said operative position and said inoperative position.

3. The apparatus as claimed in claim 1 wherein the treating zone of the barrel supported in said framework is of a substantially circular cross-sectional configuration.

4. The apparatus as claimed in claim 3 wherein the tumbling rib in said zone has substantially non-parallel sides which extend in a convergent direction into the zone and form an angle with the body member which is substantially within the range of about 10 to about 60.

5. The apparatus as claimed in claim 4 wherein the sides of the tumbling rib in the barrel are at an angle within the range of about 20 to 40 with the body member and the width of the opening in the body member is within the range of about onetenth to one-twentieth of the circumference of the treating zone.

6. The apparatus as claimed in claim 5 wherein the body member of the barrel is indented inwardly substantially opposite the elongated opening in the body member, to form the tumbling rib.

7. The apparatus as claimed in claim 6 wherein electrode members are disposed within the treating zone formed by the body member of the barrel so as to be in contact with the articles to be treated which are contained within the zone.

8. An apparatus for treating articles in bulk comprising a treating receptacle and a work carrier adapted to be disposed at said treating receptacle during the treating operation, said work carrier comprising a framework and a hollow cylindrically shaped perforate treating barrel including a pairof spaced end members and a perforated body member extending between said end members and defining an internal cylindrically shaped treating zone, said barrel mounted on said framework for rotation about an axis extending substantially longitudinally and centrally of said treating zone, said treating barrel being formed with an elongated opening extending longitudinally of the end portions there of of a width less than about one-sixth the circumference of said zone through which articles to be treated are loaded into and unloaded from said barrel, at least one tumbling rib disposed in the interior of said zone substantially opposite to said opening, supporting means at said receptacle for supporting and retaining said work carrier in appropriate position relative thereto, drive means for oscillating said barrel when said work carrier is appropriately positioned at said receptacle, and coacting stop means on said barrel and said framework selectively positionable in an operative position for restricting angular rotation of said barrel and an inoperative position enabling, unrestricted rotation of said barrel in either direction, said stop means oriented relative to said opening in the barrel to normally control the rotary movement of said barrel when disposed in said operative position so that its angular movement in either direction ranges from at least about up to an angularity below that at which articles are discharged from said opening.

9. The apparatus as claimed in claim 8 wherein the barrel has a gear at one end thereof, which gear is operably connected to a reversable motor, whereby the desired oscillatory motion is imparted to the barrel.

10. The apparatus as claimed in claim 9 wherein the reversable motor is operably connected to the gear on the barrel through a yieldable drive transmission which is adapted to yield when said stop means are disposed in relative stopping engagement.

11. The apparatus as claimed in claim 8 wherein there is provided a plurality of treating receptacles and means are provided for selectively transporting work carriers to each of said treating receptacles.

12. The apparatus as claimed in claim 11 wherein at least one of said treating receptacles includes a treating tank for containing a treating solution and means are provided for injecting treating solution into the opening in the barrel as it is oscillated beneath the level of the treating solution.

13. The apparatus as claimed in claim 11 wherein at least one of said treating receptacles includes means for injecting a drying gas into the opening in said barrel while the barrel is oscillated in said treating receptacle.

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Claims

1. An apparatus for treating articles in bulk comprising a framework and a treating barrel supported thereby, said treating barrel including a pair of spaced end members and a perforated body member extending between said end members and defining an internal cylindrically shaped treating zone, said body member formed with a longitudinally extending opening of a width less than about one-sixth the circumference of said zone and at least one tumbling rib disposed in the interior of said zone substantially opposite to said opening, means on said end members for supporting said barrEl on said framework for rotation about an axis extending substantially longitudinally and centrally of said zone, and coacting stop means on said barrel and said framework selectively positionable in an operative position for restricting angular rotation of said barrel and an inoperative position enabling unrestricted rotation of said barrel in either direction, said stop means oriented relative to said opening in said barrel to limit rotary movement thereof when disposed in said operative position in either direction between an angularity of at least about 180* up to an angularity below that at which articles are discharged from said opening.

4. The apparatus as claimed in claim 3 wherein the tumbling rib in said zone has substantially non-parallel sides which extend in a convergent direction into the zone and form an angle with the body member which is substantially within the range of about 10* to about 60*.

5. The apparatus as claimed in claim 4 wherein the sides of the tumbling rib in the barrel are at an angle within the range of about 20* to 40* with the body member and the width of the opening in the body member is within the range of about one-tenth to one-twentieth of the circumference of the treating zone.

8. An apparatus for treating articles in bulk comprising a treating receptacle and a work carrier adapted to be disposed at said treating receptacle during the treating operation, said work carrier comprising a framework and a hollow cylindrically shaped perforate treating barrel including a pair of spaced end members and a perforated body member extending between said end members and defining an internal cylindrically shaped treating zone, said barrel mounted on said framework for rotation about an axis extending substantially longitudinally and centrally of said treating zone, said treating barrel being formed with an elongated opening extending longitudinally of the end portions there of of a width less than about one-sixth the circumference of said zone through which articles to be treated are loaded into and unloaded from said barrel, at least one tumbling rib disposed in the interior of said zone substantially opposite to said opening, supporting means at said receptacle for supporting and retaining said work carrier in appropriate position relative thereto, drive means for oscillating said barrel when said work carrier is appropriately positioned at said receptacle, and coacting stop means on said barrel and said framework selectively positionable in an operative position for restricting angular rotation of said barrel and an inoperative position enabling unrestricted rotation of said barrel in either direction, said stop means oriented relative to said opening in the barrel to normally control the rotary movement of said barrel when disposed in said operative position so that its angular movement in either direction ranges from at least about 180* up to an angularity below that at which articles are discharged from said opening.