Methods of electrolytically treating portions of digitated strips and treating cell

• US 4,376,017 A
• Filed: 01/04/1982
• Issued: 03/08/1983
• Est. Priority Date: 01/04/1982
• Status: Expired due to Term

• Current Assignee: AT&T Technologies Inc (Nokia Corporation)
• Original Assignee: Western Electric Co., Inc. (Nokia Corporation)
• Inventors: Urion, Kendall D.
• Primary Examiner(s): Tufariello, T. M.
• Application Number:
  US06/337,053
• Time in Patent Office: 428 Days
• Field of Search: 204/15, 204/224 R
• US Class Current: 205/129
• CPC Class Codes: C25D 5/02 Electroplating of selected surface areas

Abstract

A pair of opposite surfaces (17 and 18) of shaped, digitated edge features (12) of a metal strip (11) are selectively treated in an electrolytic treating cell (32) while adjacent edge surfaces (22 and 23) of such features are shielded from exposure to the treatment. The desired treatment, such as a gold plating process, is accomplished on two opposite, outwardly facing surfaces of a strip of center carried pins by engaging the strip with lateral masking belts having complementary edge features. The strip and the masking belts are passed through a treating cell between paired off electrodes (40 and 41). An electric field between each electrode and the respective, adjacent surface of the strip (11) accomplishes the treatment. Slotted openings through the masking belts relieve pressure differentials in the electrolyte on either side of the strip to minimize fluid flow through gaps between the digitated strip and the masking belts.

Claims

1. A method of electrolytically treating portions of a laterally digitated strip, wherein the strip is electrically coupled to an electrical circuit, which comprises:

engaging edge features of the strip with complementary edge features of a coplanarly positioned masking belt; and

moving the strip with the engaged belt through an electrolytic bath in a treating chamber and through a gap formed by spaced treating electrodes, such that each of two oppositely outward facing surfaces of the strip are exposed to an adjacent one of the electrodes, while edge surfaces of the strip are masked by complementary edge surfaces of the masking belt.

2. A method according to claim 1, wherein moving the strip comprises:

moving the strip substantially centered through the gap between the treating electrodes.

3. A method according to claim 2, further comprising:

communicating fluid between cubicles of the chamber, such cubicles being formed by the strip and the belt within the chamber, through openings within the belt, the periphery of such openings being located totally within the belt.

4. A method according to claim 1, wherein the strip moves through the chamber, said strip being partially masked by opposed masking means extending from opposite walls of said chamber into said chamber and against surfaces of the strip;

and

the masking belt moves through a guide track in a wall of the treating chamber spaced from said masking means and extending toward such masking means.

5. A method according to claim 4, wherein the strip moves centrally through the chamber, such that digitated edges extend outward toward two opposite walls of the chamber, and said oppositely converging masking means is positioned along the direction of travel of the strip in the center of the chamber;

and wherein

engaging edge features comprises engaging each of the digitated edges with a separate masking belt, such that the combination of the two masking belts, the masking means and the strip divide the chamber into four cubicles as the strip moves through the chamber.

6. A method according to claim 5, wherein oppositely converging masking means are adjacent, resilient belts which engage center portions of the opposite, outwardly facing surfaces of the strip, and moving the strip comprises, moving the strip with two engaged, coplanarly positioned masking belts and the resilient belts in unison through the treating chamber, such that the exposed surface portions become subjected to the electrolytic bath and to the field established between the strip and the electrodes.

7. Apparatus for electrolytically treating outwardly directed surface portions of a conductive, digitated strip, wherein the strip, coupled into an electric treating circuit, is movably positioned to pass through an electrolytic treating cell having a treating cavity, at least one pair of spaced treating electrodes located in the treating cavity, and means for filling the treating cavity with an electrolytic treating fluid, which comprises:

at least one lateral masking belt, such belt having edge features complementary to edge features of said digitated strip;

means for engaging said complementary edge features of said at least one masking belt with the edge features of said digitated strip;

means for guiding said digitated strip in its movement through the cell to pass through said treating cavity and through a space between said at least one pair of treating electrodes to expose oppositely outwardly directed surfaces of said digitated strip to an electrolytic treating action, while the edge features of said strip remain protected from such electrolytic treating action by said complementary edge features of said at least one masking belt; and

means for disengaging said at least one masking belt from said digitated strip after the strip has emerged from said treating cell.

8. Apparatus according to claim 7, wherein said digitated strip comprises a plurality of spaced, parallel pins interconnected by a central carrier band, the apparatus comprising:

a first and a second lateral masking belt, said first lateral masking belt having edge features complementary to one end of the spaced pins, and the second lateral masking belt having edge features complementary to the second end of said pins in said strip, said belts being mounted spaced and in parallel to each other to interdigitatedly engage opposite sides of the strip.

9. Apparatus according to claim 8, wherein said guiding means comprises a first and a second endless guiding belt, said guiding belts being mounted opposite one another in a plane perpendicular to the plane of the strip, such that adjacent portions of said guiding belts grasp a central portion of an upper and lower surface of said strip of pins to advance and guide said pins with the laterally engaged masking belts through said electrolytic treating cell.

10. Apparatus according to claim 9, wherein adjacent portions of said guiding belts external to said treating cell guide said strip of pins into engagement with said lateral masking belts.