Grounding for enclosures

• US 5,814,762 A
• Filed: 07/25/1996
• Issued: 09/29/1998
• Est. Priority Date: 04/12/1995
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Martinez, Reuben, Tusler, Ralph Michael, Lewis, Mark S.
• Primary Examiner(s): Kincaid, Kristine L.
• Assistant Examiner(s): SODERQUIST, KRISTINA D
• Application Number:
  US08/687,306
• Time in Patent Office: 796 Days
• Field of Search: 174/35 R, 174/35 C, 174/35 MS, 174/51, 174/265, 174/266, 174/52.1, 361/799, 361/800, 361/816, 361/818, 361/753, 439/387, 439/426, 439/444
• US Class Current: 174/377
• CPC Class Codes: H05K 7/1439 Back panel mother boards
• CPC Class Codes: H05K 9/0016 having a spring contact
• CPC Class Codes: Y10S 174/34 PCB in box or housing

Abstract

An apparatus is provided to reduce the amount of EMI generated by a circuit. The grounding of an enclosure is improved by providing a number of shaped protuberances, the protuberances having an end that penetrates a conductive region of a circuit board, such that when the circuit board is mounted to the support member, the protuberances make a penetrating electrical contact and provides for additional ground paths, thereby reducing the EMI generated by the assembly.

Claims

1. An enclosure, comprising;

a circuit board with a surface having a solid electrically conductive surface region at the surface;

an electrically conductive wall including an electrically conductive grounding element on a surface of the wall at an edge of the wall, the grounding element having sides, all such sides narrowing as the sides extend from the surface of the wall to terminate at a common vertex spaced from the surface of the wall; and

a mechanism joining the wall at the edge to the circuit board with the vertex of the grounding element pressing against the solid electrically conductive surface region at the surface of the circuit board to penetrate the solid electrically conductive surface region and establish an electrically conductive relationship with the electrically conductive surface region, the path of penetration of the vertex of the grounding element extending in a direction perpendicular to the solid electrically conductive surface region at the surface of the circuit board.

2. The enclosure as recited in claim 1 wherein said grounding element is integrally formed from said surface of the wall.

3. The enclosure as recited in claim 1 wherein the vertex of the grounding element is spaced 0.015 inches from the surface of the wall.

4. The enclosure as recited in claim 1 wherein said grounding element has a pyramidal shape.

5. The enclosure according to claim 4 wherein the vertex is spaced between 0.005 and 0.015 inches, inclusive, from the surface of the wall.

6. The enclosure as recited in claim 1 wherein the vertex of the grounding element is spaced less than or equal to 0.015 inches from the surface of the wall, and the vertex of the grounding element is spaced greater than or equal to 0.005 inches from the surface of the wall.

7. The enclosure according to claim 1 wherein the circuit board is a second wall of the enclosure.

8. The enclosure according to claim 1 wherein the wall includes a flange at the edge of the wall and wherein the surface of the wall is on the flange.

9. The enclosure according to claim 8 wherein the mechanism joins the circuit board to the flange.

10. The enclosure according to claim 1 wherein the grounding element is soldered to the surface of the wall.

11. The enclosure according to claim 1 wherein the circuit board further includes a non-conductive film disposed on the surface of the circuit board over the electrically conductive surface region, arid wherein the vertex of the grounding element penetrates the non-conductive film to establish an electrically conductive relationship with the electrically conductive surface region.

12. The enclosure according to claim 1 wherein the circuit board and the wall each have a mounting hole, the mounting holes being aligned to each other, and wherein the mechanism includes a screw extending through the mounting holes.

13. An enclosure, comprising:

a circuit board with a surface having an electrically conductive region and a non-conductive film disposed on the surface of the circuit board over the electrically conductive region;

an electrically conductive wall including an electrically conductive grounding element on a surface of the wall at an edge of the wall, the grounding element having sides, all such sides narrowing as the sides extend from the surface of the wall to terminate at a common vertex spaced from the surface of the wall; and

a mechanism joining the wall at the edge to the circuit board with the vertex of the grounding element penetrating the non-conductive film to establish an electrically conductive relationship with the electrically conductive region, the path of penetration of the vertex of the grounding element extending in a direction perpendicular to the surface of the circuit board.

14. An enclosure, comprising:

a first surface having a solid electrically conductive surface region at the first surface; and

a second surface including an electrically conductive protuberance on the second surface, the protuberance having sides, all such sides narrowing as the sides extend from the second surface to terminate at a vertex spaced apart from the second surface, the vertex of the protuberance pressing against the solid electrically conductive surface region at the first surface to penetrate the solid electrically conductive surface region and establish an electrically conductive relationship between the protuberance and the solid electrically conductive surface region when the surfaces are brought together, the path of penetration of the vertex extending in a direction perpendicular to the solid electrically conductive surface region at the first surface.

15. The enclosure as recited in claim 14 wherein said protuberance has a conical shape.

16. The enclosure according to claim 15 wherein the vertex is spaced between 0.005 and 0.015 inches, inclusive, from the surface of the wall.

17. The enclosure of claim 14 wherein the first surface is an electrically non-conductive surface and the second surface is an electrically conductive surface.