Card-receiving electronic device having grounding spring

• US 5,357,402 A
• Filed: 05/15/1992
• Issued: 10/18/1994
• Est. Priority Date: 02/24/1992
• Status: Expired due to Fees

• Current Assignee: ITT Corporation (ITT, Inc.)
• Original Assignee: ITT Corporation (ITT, Inc.)
• Inventors: Anhalt, John W.
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): LEDYNH, BOT L
• Application Number:
  US07/857,914
• Time in Patent Office: 886 Days
• Field of Search: 361/212, 361/220, 361/736, 361/752, 361/753, 361/816, 361/756, 361/817, 361/818, 174/51, 174/35 R, 174/35 GC, 174/35 MS, 439/607, 439/608, 439/609, 439/610
• US Class Current: 361/753
• CPC Class Codes: G06K 19/07735 the record carrier comprising means for protecting against electrostatic discharge
• CPC Class Codes: G06K 19/07743 External electrical contacts
• CPC Class Codes: G06K 7/0047 for reading/sensing record carriers having edge contacts
• CPC Class Codes: G06K 7/0082 comprising an arrangement for protection against electrostatic discharge, e.g. by grounding part of the conductive housing
• CPC Class Codes: H01R 13/6485 Electrostatic discharge protection in general H05F1/00, for electric apparatus H05K9/0067
• CPC Class Codes: H01R 2201/06 for computer periphery

Abstract

A grounding spring is provided for discharging static electricity on a card as the card is inserted into an electronic device and for thereafter grounding the card, which minimizes electromagnetic radiation during electrostatic discharge in a simple and easily mounted construction. The grounding spring (60, FIG. 3) is formed of sheet metal and has a card-engaging part 64 lying within a recess of a card-guiding track (72). The grounding spring has a downwardly extending leg (90) that extends down into a hole (92) of a circuit board lying under the card-receiving mechanism, and has a substantially 180° loop (112) connecting the card-engaging part to the downward leg.

Claims

1. A card-receiving electronic device that includes a circuit board having an upper surface, a plurality of conductive traces and a ground plane, said electronic device also including a card-receiving mechanism mounted over said circuit board upper surface with said mechanism including a pair of primarily horizontally-extending guide tracks that guide a card in longitudinal movement into and out of said mechanism, characterized by:

a grounding spring having an elongated upper portion forming a card-contacting part positioned along one of said guide tracks, and having a downwardly-extending leg with a lower leg end electrically connected to said circuit board ground plane.

2. The electronic device described in claim 1 wherein:

said circuit board has a plurality of feet-receiving holes and has a grounding hole with metal plated ground hole walls connected to said circuit board ground plane;

said lower leg end projects into said grounding hole and is connected to the metal walls of said grounding hole.

3. The electronic device described in claim 1 wherein:

said tracks guide said card in forward and rearward longitudinal directions respectively into and out of said mechanism;

said card-receiving mechanism includes first and second track walls forming said guide tracks with each track wall having an inner side facing a card and an opposite outer side, with a first of said track walls having a laterally-extending track hole therein forming front and rear track hole walls;

said grounding spring is formed of sheet metal and said upper portion has a rear end forming a loop with said loop being looped about said front track hole wall, with said leg extending from an outer side of said looped rear end.

4. The electronic device described in claim 1 wherein:

a first of said guide tracks has top and bottom card edge guides forming inside guide corners that guide edges of said card, said first guide track forms a recess between said edge guides, and said card-engaging part of said spring has a height that is less than the vertical distance between said guide corners and lies in said recess.

5. A combination of a card that contains electronic circuitry and an electronic device that has a slot for receiving said card, comprising:

a card receiving mechanism mounted on said electronic device, which includes a frame having a card-receiving slot and a pair of laterally spaced card-guiding tracks aligned with said card-receiving slot which guides said card in forward movement into said card-receiving slot, said card having a front end forming a connector and said card-receiving slot having a front end with a frame connector that includes multiple contacts, with said frame connector positioned to mate with said card connector when said card is fully inserted into said frame;

a circuit board lying under said card-receiving mechanism, said board having a plurality of conductive traces connected to said contacts of said frame connector, and said board having a ground plane;

said card having opposite edges that each have upper and lower corners and said card having at least one card ground contact connected to said electronic circuit, with said card ground contact lying at a first of said card edges;

a first of said tracks has upper and lower edge guides forming a recess with corners, that guides top and bottom corners of a first edge of said card;

a grounding spring having a card-contacting part lying in said recess and bearing against said card ground contact, said spring having a downwardly extending leg extending to said circuit board and electrically connected to said circuit board ground plane.

6. The combination described in claim 5 wherein:

said first track has an inner side facing said card and an opposite outer side, and said first track has a track hole at the level of said recess, said track hole having forward and rearward hole walls;

said grounding spring has a looped part extending in a substantially 180°

loop about said track forward hole wall, with one end of said loop merging with card-contacting part and with the other end of said loop merging with said leg.