Conductive gasket including internal contact-enhancing strip

• US 6,818,822 B1
• Filed: 04/08/2004
• Issued: 11/16/2004
• Est. Priority Date: 04/08/2004
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Koschmeder, Max John Christopher, Gilliland, Don Alan, Huettner, Cary Michael
• Primary Examiner(s): Ngo, Hung V.
• Application Number:
  US10/821,145
• Time in Patent Office: 222 Days
• Field of Search: 174/35.R, 174/35.GC, 361/816, 361/818, 277/920
• US Class Current: 174/357
• CPC Class Codes: H05K 9/0015 Gaskets or seals
• CPC Class Codes: Y10S 277/92 Seal including electromagnetic shielding feature

Abstract

A novel conductive gasket including an internal contact-enhancing strip provides improved contact performance in electromagnetic interference prevention and other applications. A metal mesh or conductive plastic covers a substantially rigid internal strip that includes protrusions that either bend or penetrate the gasket cover in order to enhance contact with another conductive surface. The cover may include holes aligned with the protrusions so that the protrusions pass through the holes when the gasket is compressed, or the protrusions may penetrate a mesh or plastic cover. An internal foam piece may be provided behind the internal strip to restore the shape of the when compressive force is removed and a second internal foam piece may be provided between the strip and the cover for maintaining the shape of the gasket. The protrusions on the internal strip may range from needle-shaped protrusions for puncturing a coating to relatively smooth bumps for bending the surface of the cover when the gasket is compressed.

Claims

1. A conductive gasket for providing a low-impedance contact between a first surface and a second surface, said gasket comprising:

a flexible cover for contacting the first surface on an exterior face of said conductive cover when said gasket is compressed;

a contact strip disposed on an anterior face of the conductive cover and having a plurality of protrusions disposed thereon for improving contact between said gasket and said first surface when said gasket is compressed; and

a conductive path between said second surface and at least one of said flexible cover and said contact strip for providing a low-impedance path between said first surface and said second surface when said gasket is compressed.

2. The conductive gasket of claim 1, wherein said contact strip is a metal contact strip and said protrusions are conductive projections from an exterior face of said contact strip facing said anterior face of the conductive cover, and wherein said conductive projections pass through said flexible cover when said gasket is compressed.

3. The conductive gasket of claim 2, wherein said conductive cover is a wire mesh, whereby said conductive projections pass through said wire mesh by displacing said wire mesh when said gasket is compressed.

4. The conductive gasket of claim 2, wherein said protrusions extend through said conductive cover when said gasket is uncompressed and pass further through said flexible cover when said gasket is compressed.

5. The conductive gasket of claim 2, wherein said flexible cover includes a plurality of perforations therethrough and aligned with said projections, whereby said conductive projections pass through said perforations when said gasket is compressed.

6. The conductive gasket of claim 2, wherein said flexible cover is a flexible plastic strip having a conductive coating on at least said exterior surface.

7. The conductive gasket of claim 1, further comprising a compressible foam layer disposed on an anterior face of said contact strip facing away from said anterior face of said flexible cover for applying force to said contact strip when said gasket is compressed.

8. The conductive gasket of claim 7, further comprising a second compressible foam layer disposed on an exterior face of said contact strip between said contact strip and said flexible cover for maintaining a shape of said gasket.

9. The conductive gasket of claim 1, wherein said compressible foam layer is a conductive foam layer, and wherein said conductive path is provided by contact between said contact strip and said second surface via contact between said contact strip and said conductive foam and further provided by contact between said conductive foam and said second surface.

10. The conductive gasket of claim 1, wherein said protrusions bend said flexible cover, but do not penetrate said flexible cover when said gasket is compressed, whereby electrical contact with said first surface is improved by bends in said flexible cover.

11. The conductive gasket of claim 1, wherein said conductive path is provided by contact between said contact strip and said second surface.

12. The conductive gasket of claim 1, wherein said flexible cover is a conductive cover, and wherein said conductive path is provided by contact between said cover and said second surface.

13. The conductive gasket of claim 1, wherein said contact strip is a metal contact strip and said protrusions are conductive projections extending from both an exterior face and an anterior face of said contact strip, wherein said conductive projections pass through said flexible cover when said gasket is compressed, and wherein said protrusions extending from said anterior face provide at least a portion of said conductive path via contact with said second surface.

14. The conductive gasket of claim 1, wherein said contact strip is a first metal contact strip, said protrusions are first conductive projections extending from an exterior face of said contact strip, wherein said first conductive projections pass through said flexible cover when said gasket is compressed, and further comprising:

a second metal contact strip disposed at a predetermined angle greater than zero in an axis perpendicular to a longitudinal extension of said gasket and having second conductive projections disposed on an exterior face thereof, wherein said flexible cover is further disposed over said second metal contact strip, and wherein said second conductive projections pass through said flexible cover to contact said second surface when said gasket is compressed.

15. The conductive gasket of claim 1, wherein said contact strip is in the form of a cylindrical conductor, and wherein said protrusions extend radially from a central axis of said cylindrical conductor.

16. A conductive gasket for providing a low-impedance contact between a first surface and a second surface, said gasket comprising:

a wire mesh cover for contacting the first surface on an exterior face of said conductive cover when said gasket is compressed;

a contact strip disposed on an anterior face of the conductive cover and having a plurality of protrusions disposed thereon for penetrating said wire mesh cover when said gasket is compressed;

a first compressible foam layer disposed on an anterior face of said contact strip facing away from said anterior face of said flexible cover for applying force to said contact strip when said gasket is compressed;

a second compressible foam layer disposed on an exterior face of said contact strip between said contact strip and said wire mesh cover for maintaining a shape of said gasket; and

a conductive path between said second surface said flexible cover, whereby a low impedance is established between said second surface, said wire mesh cover and said contact strip when said gasket is compressed.

17. A method for manufacturing a conductive gasket, said method comprising:

forming a contact strip having a plurality of protrusions disposed thereon for improving electrical contact of said gasket when said gasket is compressed; and

covering said contact strip with a flexible cover to form said gasket, whereby said protrusions pass through said flexible cover when said gasket is compressed.

18. The method of claim 17, wherein said covering comprises wrapping a wire mesh cover around said contact strip.

19. The method of claim 17, further comprising placing said contact strip over a compressible foam layer prior to said covering, and wherein said covering covers said compressible foam layer and said contact strip.

20. The method of claim 17, further comprising forming perforations in said flexible cover prior to said covering, whereby said protrusions pass through said perforations in said cover.