|Publication number||US3746633 A|
|Publication date||Jul 17, 1973|
|Filing date||Mar 26, 1971|
|Priority date||Aug 24, 1970|
|Also published as||CA933882A1, DE2115424A1, DE2115424B2, DE2115424C3|
|Publication number||US 3746633 A, US 3746633A, US-A-3746633, US3746633 A, US3746633A|
|Inventors||Ito H, Miyato A, Okubo H, Suzuki A, Tomita C|
|Original Assignee||Nippon Kokan Kk|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (8), Classifications (13)|
|External Links: USPTO, USPTO Assignment, Espacenet|
July 11, 1973 A WA ET AL 3,746,633
APPARATUS FOR ELECTROPLATlNG WORKPIEZCES .LNCLUUING MEANS TO VARY THE POST'TION OF'THE WORKP'IECES Filed Marcn 26, 1971 2 Sheets-Sheet 1 FIG.I
July 17, 1973 AKlRA MIYATO ET AL 3,746,633
APPARATUS FOR ELECTROPLATING WORKPIECES INCLUDING MEANS TO VARY THE POSITION OF THE WORKPIECES Filed Maren 26, 1971 2 Sheets-Sheet 2 United States Patent 3 746,633 APPARATUS FGR E LECTROPLATING WGRK- PIECES INCLUDENG MEANS TO VARY THE PQSHTION OF THE WORKPIECES Akira Miyato, Hideyo Okubo, Chikayoshi Tornita, Akio U.S. Cl. 204-231 Claims ABSTRACT OF THE DISCLOSURE An apparatus for electroplating wherein cathode means are provided to mount a plurality of articles to be plated, there being a mechanism for pressing said articles to be plated to the surfaces of said cathode means during the period of supply of current and a rotating mechanism to vary the position of the articles to which current is supplied while at the same time the supply of current is stopped, the pressing mechanism and the rotating mechanism being connected to an interlocking mechanism so that the supply of current is stopped and the pressure of the pressing mechanism is released before activation of the rotating mechanism.
The present invention relates to an apparatus for forming a uniform and sturdy film electroplated on a surface of an article. The article may be a cylindrically-shaped article of various lengths such as a fastener, a bolt, a nail and the like.
In the prior art, a barrel type apparatus is used or electroplating, with an aqueous solution, such cylindrically-shaped small articles. An electroplating apparatus of a barrel type, however, has drawbacks; e.g., when applied to fused salt electroplating by electrolysis, the electrical resistance at the point contact of an article or articles to be plated and a cathode or the mutual point contact of articles to be plated is so unstable and great that the area in the region of a part through which current has been supplied remains defectively plated after completion of plating. The article thus electroplated has a poor durability as a whole. It is a known fact from the past experiments by the inventors of this invention that said electroplating apparatus of a barrel type has numerous problems in fused salt electroplating by electrolysis.
SUMMARY OF THE INVENTION The present invention relates to an apparatus for use in electroplating articles, in which a pressing mechanism is provided to connect articles to be plated firmly to a cathode in a plating bath, and in addition to said pressing mechanism, a rotating mechanism to rotate articles to be plated is provided. The rotating mechanism is brought into action at predetermined intervals when the pressure of the pressing mechanism is nil. Thus, articles to be plated are rotated to change the parts in contact with the cathode to which current is supplied within a short period of time. A supplemental anode may be provided in addition to said two mechanisms.
The present invention will now be described in more detail with reference to the accompanying drawings in which:
FIG. 1 is a front view of an apparatus embodying the present invention;
FIG. 2 is a side-sectional view thereof;
FIG. 3 is a partially enlarged view of the part A in FIG. 1; and
FIG. 4 is a partially enlarged view of the part B in FIG. 2.
'In the drawings, a cathodic conductor 2 carrying a plurality of articles to be plated such as fasteners, bolts, nails and the like is supported in a plating bath 6 through a supporter 5 freely and suspendably fixed to a bracket 4 on a lid 28 of a plating vessel 3. The parts '7 mounting the articles to be plated have a wave shape, the variable number of articles 1 to be plated being mounted within the recesses or troughs so formed. In this embodiment of the present invention, two cathodic conductors 2 and 2' are arranged in parallel in a vertical direction in the drawings as if supporting both ends of articles to be plated (see FJG. 2). The number of said cathodic conductors in parallel is proportionate to the size of a plating vessel 3 and may be optionally increased. On the other hand, anodes 8 as shown in FIG. 2 are arranged on the upper portions of both ends and in the lower portion at the centre of the articles 1 to be plated and are fixed to a lid 28 so as to be immersed in a plating bath in order to provide a plating film having a uniform thickness. Further, supplemental anodes 9 may be fixed to a bracket if so required. The ends of article 1 to be plated often have indented parts. The supplemental anodes 9 cause a remarkably efiicient electroplating treatment on the indented parts. It is preferable to arrange a tip of a supplemental anode '9 adjacent an article to be plated with a very small distance between the two with the extreme tip of said supplemental anode extending beyond insulation 10. The arrangement of said supplemental anodes *9 is an optional but substantial feature of the present invention.
Parts 7 of the cathodic conductors carrying articles 1 to be plated act as the parts to which current is supplied, said parts being partially covered with insulation 11 such as Teflon or the like. When the parts not covered with Teflon and the like are defined to the parts 7 and contacting parts with the articles to be plated, said parts have the operational advantage that unnecessary current is not supplied between the parts 7 and the articles to be plated (refer to FIG. 3). In this embodiment of the present invention, only one part (as in FIG. 3) is exposed. Said part is a part where current is supplied and not plated, so that it should preferably be as small as possible.
The parts 7 of a cathode where current is supplied are placed horizontally in a plating bath, a pressing mechanism 12 being activated toward articles 1 to be plated whose ends are sustained therebetween. The pressing mechanism presses the articles 1 to be plated to the exposed part of a cathodic part where current is supplied to maintain a firm contact during the supply period for current. The pressing mechanism is not limited to the one illustrated in the drawings. However, as shown in the drawings the pressing mechanism 12 uses resilient rods 14 elongated to a letter J-shape, each rod 14 includes a piano wire 13 sheathed in a Teflon tube 26 and a glass tube 27 provided at the pressing part. The pressing mechanism is located at parts marked C in FIG. 1. The position of the dotted line shown in FIG. 3 is the position of a pressing part when articles to be plated are not mounted on a cathodic conductor. A pressing part is so constructed that when a pressure is applied to the articles to be plated utilizing constant elasticity it will be placed on the solid line illustrated in FIG. 3. It is also possible to arrange a magnet (not shown in the drawings) beneath a cathode and activate the magnetism to attract and firmly contact articles to be plated on a surface of the cathode.
As shown in FIGS. 1 and 2, a rotating mechanism 15 to vary the positions of the articles 1 to be plated in relation to the cathode is provided corresponding to the pressing mechanism 12. The mechanism 15 includes a glass rod 16 arranged in parallel with the horizontal point of the cathodic conductor, both ends of said glass rod being supported by supporting rods 17 and 17, so as to be able to rotate momentarily all of the plurality of articles to be plated mounted in the horizontal direction. The glass rods are rotated along the loci X and X shown by dotted circles. When the connecting face 18 of said glass rods 16 is so slanted as 18 in FIG. 2, articles 1 to be plated whose indented end parts come close to the supplemental anodes 9 are caused to rotate under a preferable condition.
Both pressing and rotating mechanisms 12 and 15 aforementioned are so arranged that upon completion of the former action the latter action is started by means of an interlocking mechanism 19. The interlocking mechanism 19 may be a conventionally known link mechanism. In the embodiment shown, a crank shaft 20 is employed and is so arranged that when a crank part 21 is rotated by a suitable motor not shown in the drawings, both pressing and rotating mechanisms 12 and 15 are interlocked by means of a pin 29. For this reason, the upper end of a rod 14 of the pressing mechanism 12 and supporting rods 17 and 17' of the rotating mechanism 15 are connected to the identical crank part 21 of the crank shaft. 22 denotes a shaft pin thereof, and 23 a chain engaging each shaft, respectively. As shown in FIG. 2, a receiving member 24 maintains a horizontal rod 25 and acts to prevent articles 1 to be plated from deviating from the predetermined position of a cathodic part where current is supplied. The horizontal rod 25 is freely attachable to and removable from the receiving member 24 and enables articles to be plated to be easily placed in and removed from a cathodic conductor having a wave shape.
The action and operation of the novel apparatus for electroplating comprising such a structure as aforementioned will now be described. Articles 1 to be plated are mounted on the parts 7 in the troughs of the wavy shape of the cathode 2 immersed in the plating bath 6 by a proper means. The supplemental anodes 9 are preliminarily so set as to be placed in a predetermined position of the indented part at the ends of articles to be plated. At this time, the pressing mechanism 12 of the articles to be plated is so placed as not to press the articles to be plated. Then the crank shaft 20 is rotated to press the articles to be plated by means of rods 14 of the pressing mechanism 12 so as to cause the articles 1 to be plated to come into firm contact with the cathodic part where current is supplied 7 (refer to FIG. 3). The terminals from the power supply required for electroplating are, of course, preliminarily connected to the cathodic conductor and the anode, respectively. During the plating process, a timer is used so that the rotating mechanism 15, which changes the position of the parts to which current is supplied, is activated to repeat the passage of current and rotation after a predetermined period of time. In the example in accordance with the present invention after the current is supplied for 16 seconds in a stationary state, crank shaft 20 is rotated, rods 14 of the pressing mechanism 12 rise in accordance with the rise of a rotating glass rod 16 along the loci X and X' from the lower position during the next half a second. At this time the rotating rod 16 contacts the articles to be plated at the uppermost position to rotate the same. When he crank shaft 20 makes one rotation and again causes a firm pressure on the articles to be plated, the part to which current is supplied is varied from that at the time of the previous plating.
An example of the plating process is described as follows: (when plating pieces of fasteners having a diameter of 9 mm a length of 52 mm).
The total plating time was 30 minutes and for the first 5 minutes after the start of plating a DC current of 0.5 a. was supplied, a cycle of electrolysis in a stationary state 16 sees. and rotating time 0.5 sec. was then repeated.
After then, a DC current of 4 a. was supplied after the first 5 minutes until 30 minutes since the start and a cycle of electrolysis in a stationary state 63 secs. and rotating time 0.5 sec. was repeated.
0.8 a. of current was supplied to the supplemental anode during the last 5 minutes of the plating time.
When current supply is started after the articles to be plated have been rotated and then pressed against a cathode, it is preferable to decrease the current to prevent the generation of sparks at the part to which current is supplied. It is also preferable to decrease the current in the same manner when the supplying current is stopped to start the rotation of the articles to be plated.
By using the novel apparatus for electroplating of the present invention, it is possible to perform the electroplating process highly efficiently. Various effects obtained in accordance with the present invention are listed as follows:
(a) An accurate and sufficient supply of current to the articles to be plated is provided as the current is supplied when the articles to be plated are pressed on the cathodic conductor and in firm contact with the same.
(b) It is possible easily to arrange a supplemental electrode for an indented part on an end and uniformly to plate even an inner surface of said indented part as the plating process is carried out in a stationary state.
(c) Traces partially beautifully or poorly electroplated due to pressure do not stay on the articles to be plated as a plating process is performed because of the variations of the part to which current is supplied at predetermined times.
(d) Excess current is not used except for plating and high efficiency can be obtained as in a plating bath the specific part where current is supplied is in complete contact with the articles to be plated and other parts are coated with insulation.
(e) A smooth operation is performed by intermittently activating both pressing and rotating mechanisms, to vary and rotate the part to which current is supplied.
(f) Current is supplied through means such as a narrow electric wire coated with Teflon to the articles to be plated, and said electric wire also maintains the articles to be plated, so that current is not supplied to parts with the exception of the articles to be plated. There is no obstacle in the vicinity of the articles to be plated, thus providing a desirable condition for supplying of a plating solution and current.
The aforementioned description is mainly concerned with fused salt aluminium electroplating. The present invention, however, is not limited to the same, but is ap plicable to plating metals other than aluminium in an aqueous solution.
What is claimed is:
1. An apparatus for electroplating in an electroplating bath, comprising:
cathode means on which may be supported a plurality of cylindrically-shaped articles to be plated, parts of said cathode means being shaped to receive said cylindrically-shaped articles,
a rotating mechanism for varying the position of said articles so that different parts of said articles are brought into contact with said cathode means,
a mechanism for pressing said articles to be plated against the cooperating parts of said cathode means during the time of current supply to said cathode means; and
control means for synchronizing the operation of said pressing mechanism and said rotaitng mechanism so that the pressing mechanism is inactive while the position of said articles is being changed.
2. An apparatus for electroplating in an electroplating bath, comprising:
cathode means on which may be mounted a plurality of articles to be plated,
a mechanism for releasably pressing said articles to be plated against the surfaces of said cathode means, a rotating mechanism for varying the position of said articles so that ditferent parts of said articles are brought into contact with said cathode means,
means for controlling the supply of current to said cathode means,
means for synchronizing the operation of the pressing mechanism and the rotating mechanism so that the pressing mechanism is inactive while the position of said articles is being changed, and
means for interengaging the control means and the synchronizing means so that supply of current is stopped upon activation of said rotating mechanism.
3. Apparatus according to claim 1 wherein said cathode means includes a plurality of troughs for receiving said articles to be plated.
4. Apparatus according to claim 3 wherein each trough is partially covered with insulating material, there being an absence of insulating material at a part of a trough contacted by an article received therein.
5. Apparatus according to claim 1 wherein the pressing mechanism includes a plurality of resilient rods, each rod having a part which is shaped and positioned to apply pressure to an article positioned for plating.
6. Apparatus according to claim 1 including means for controlling the supply of current to said cathode means, and means for interengaging the supply current control means and said synchronizing means so that supply or current is stopped upon activation of said rotating mechanism.
7. Apparatus according to claim 2 including a supplemental anode adapted to be located adjacent to the posi- 1 tion of one end of an article to be plated when said article is supported on said cathode means.
8. Apparatus according to claim 2 wherein said cathode means includes a plurality of troughs for receiving said articles to be plated.
9. Apparatus according to claim 8 wherein each trough is partially covered with insulating material, there being an absence Off insulating material at a part of a trough contacted by an article received therein.
10. Apparatus according to claim 2 wherein the pressing mechanism includes a plurality of resilient rods, each rod having a part which is shaped and positioned to apply pressure to an article positioned for plating.
References Cited UNITED STATES PATENTS 2,541,597 2/ 1951 Midling 204297 R 3,133,007 5/1964 Creese et al. 204198 870,545 11/1907 Clough 204222 FOREIGN PATENTS 1,582,692 10/ 1969 France 204231 JOHN H. MACK, Primary Examiner W. I. SOLOMON, Assistant Examiner US. Cl. X.R. 204297 R
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|U.S. Classification||204/228.8, 204/228.9, 204/227, 204/232, 204/273, 204/229.2|
|International Classification||C25D21/00, C25D21/10, C25D17/00, C25D3/66, C25D3/00|