Chemistry: electrical and wave energy – Apparatus – Electrolytic
Reexamination Certificate
2000-09-01
2002-01-29
Bell, Bruce F. (Department: 1741)
Chemistry: electrical and wave energy
Apparatus
Electrolytic
C204S297010, C204S297060, C204S297100, C204S297140, C204S297150, C248S226110, C248S227300, C248S229160, C248S316100, C248S689000, C267S158000, C267S159000, C267S160000, C267S163000, C269S047000, C269S049000, C269S050000, C269S059000, C269S060000, C269S074000, C269S076000, C269S095000, C269S097000, C269S101000, C269S152000, C269S153000, C211S120000
Reexamination Certificate
active
06342138
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to article holders or clamps for electroplating articles.
BACKGROUND OF THE INVENTION
It is known in the art of electroplating to use frames on which are removably installed circuit boards or the like articles to be electroplated, for holding them while they are being submerged in large acid tanks or baths. The acid bath is one of several steps involved in the manufacture of a printed circuit board. The acid solution is usually either chloridric acid or sulfuric acid. The overhanging flames are made of an electrically conducting material sealed in a fluid-tight and electrically insulating material to substantially slow down the corrosive effects of the acidous vapors from the bath of acid, and are sealingly electrically connected to the articles to be plated. The frames are connected to a cathode element, or flight bar, and are subjected to an electrical current which is transmitted through the frame structure, the article and the liquid acid. An anode element is also submerged in the acid bath, spaced from the circuit board, for example of a distance of 6 to 10 inches. The potential difference between the article and the reducing agent anode element allows the metal composing the latter to migrate and attach itself onto the article. The metal composing the anode element can be for example copper, or any other suitable material combining a proper oxydo-reduction potential and suitable conductive characteristics.
An electroplating rack is shown in U.S. Pat. No. 4,176,039 issued in 1979 to J. C. Wismer. This electroplating rack includes clamps adapted to each hold one circuit board while it is submerged in an acid bath. The clamp holds the flat board on both sides, by means of a screw on a first side and a stopper on the other side. Both the screw and the stopper have electrically conducting cores destined to engage the board and connected to the flight bar, the cores being enveloped in sealing sleeves to help prevent corrosion thereof.
A first problem with the Wismer device is that the screw is likely to damage the board when it is rotated and pressed against the board. This is especially true when ultra-thin boards are to be installed on the clamp. Ultra-thin boards can be as thin as 0.002 inch. The damage to these board results mainly from the rotational movement and associated shearing effect of the screw, not from the transverse pressure applied on the board. In the case of the Wismer device, the resilient end seal provided at the screw tip around the electrically conducting core, is likely to enhance this problem due to the higher friction coefficient between the resilient seal material and the board. However, this seal is essential, or else the acid solution would have free access to the conducting core, the latter then being corroded at a high rate.
Another general problem with the Wismer device, is related to the maintenance of the electroplating rack. Although an end seal is provided at the screw tip, corrosion of the conducting core will still gradually occur at the screw tip. To remove the plating formed at the screw tip and resulting from this corrosion, the rack has to be submerged in a nitric acid bath or the like suitable solution which will allow the plating to be removed, which is a tedious and time-consuming operation. Alternately, the corroded parts, i.e. the screw tip and the stopper tip in the present case, have to be replaced, which is again time consuming, in addition to being expensive.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a clamp for holding articles to be electroplated, which has a replaceable connecting element which connects the article to the cathode flight bar.
It is a further object of the present invention to provide a connecting element which prevents friction movements of the clamp to occur against the article surface.
It is yet another object of the present invention that the connecting element allow the electric current to be transmitted on both sides of the article.
SUMMARY OF THE INVENTION
Therefore, in accordance with the objects of the invention, there is disclosed a spring clip for use as a connection member on an electroplating clamp, said spring clip being integrally formed of a folded, generally flat electrically conducting material and comprising a first and a second arm member and an arcuate foot member integrally linking said first and second arm members, said foot member having: a resilient elbow portion, allowing relative pivotal displacement of said first and second arm members between an opened condition, in which said first and second arm members spacedly register with one another and define a gap therebetween, and a closed condition, in which said first and second arm members are pivoted towards each other to at least reduce said gap therebetween, with said resilient elbow portion continuously biasing said first and second arm members towards said opened condition;—a first resilient lip, integrally formed between said elbow and said first arm member, said first lip protruding outwardly relative to said gap; and—a second resilient lip, integrally formed between said elbow and said second arm member, said second lip protruding inwardly toward said gap and toward said first lip.
Alternately, the invention more generally concerns a clamp for use on an electroplating rack of the type having an electrically conducting flight bar, said clamp comprising:—a main body made of an electrically insulating material;—an attachment member, for fixed attachment of said main body to the rack;—a conducting bridge member carried by said main body for electrical connection with the flight bar of said rack;—a spring clip carried by said main body and able to come into electrical contact with said bridge member, said spring clip being made of an electrically conducting material and being provided with first and second arms and an arcuate pivotable foot member linking said first and second arms, said pivotable foot member allowing relative pivotal displacement of said first and second arms between an opened condition in which said first and second arms spacedly register with one another so as to define a gap therebetween, and a closed condition, in which said first and second arms are pivoted towards each other to at least reduce said gap therebetween and in which said spring clip is in electrical contact with said bridge member;—a selectively operable pressure member carried by said main body and engageable with said spring clip so as to selectively pivot said first and second arms relative to each other from said opened condition towards said closed condition; and—a biasing member continuously biasing said first and second arm members toward said opened condition.
Preferably, said foot member of said spring clip is resilient and integrally links said first and second arms, said biasing member being said resilient foot member and continuously biasing said first and second arms towards said opened condition. Said spring clip could then be integrally formed of a folded, generally flat electrically conducting sheet, and wherein said foot member integrally linking said first and second arms comprises:—a resilient elbow portion allowing relative pivotal displacement of said first and second arms between said opened condition and said closed condition, with said resilient elbow portion continuously biasing said first and second arms towards said opened condition;—a first resilient lip, integrally formed between said elbow and said first arm, said first lip protruding outwardly relative to said gap; and—a second resilient lip, integrally formed between said elbow and said second arm, said second lip protruding inwardly toward said gap and toward said first lip.
Preferably, said pressure member is a screw threadingly engaging said clamp main body through a through-bore provided therein, said screw being able to gradually apply pressure on said spring clip second arm when said screw is rotated in a first direction to pivot said second arm towards said first arm and
Bell Bruce F.
M & B Plating Racks Inc.
Martineau Francçois
LandOfFree
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