Shielded computer printed circuit board retention apparatus

• US 5,398,156 A
• Filed: 03/22/1993
• Issued: 03/14/1995
• Est. Priority Date: 03/22/1993
• Status: Expired due to Term

• Current Assignee: Dell USA LP (Dell Technologies Inc.)
• Original Assignee: Dell USA LP (Dell Technologies Inc.)
• Inventors: Gandre, Jerry D., Steffes, Karl M.
• Primary Examiner(s): Phillips, Michael W.
• Application Number:
  US08/034,057
• Time in Patent Office: 722 Days
• Field of Search: 439/59, 439/92, 439/325, 439/327, 439/328, 439/345, 439/347, 439/629, 439/931, 361/679, 361/683-686, 361/724-727, 361/740-742, 361/746, 361/747, 361/753, 361/754, 361/756, 361/759, 361/798-802, 361/816, 361/818, 361/825-827, 174/138 D, 174/138 G, 29/467, 29/830-832
• US Class Current: 361/679.58
• CPC Class Codes: G06F 1/182 with special features, e.g. for use in industrial environments; grounding or shielding against radio frequency interference [RFI] or electromagnetical interference [EMI]
• CPC Class Codes: H05K 7/1429 for circuits carrying a CPU and adapted to receive expansion cards
• CPC Class Codes: Y10S 439/931 Conductive coating
• CPC Class Codes: Y10T 29/49128 Assembling formed circuit to base

Abstract

A printed circuit board is mounted on the inner side of a conductively coated plastic computer housing wall using a screwless retention and grounding system molded integrally with the housing wall and including a spaced series of upstanding hook plate portions extendable through a series of elongated slots in the circuit board body and positioned in spaced, facing relationships with corresponding contact tab portions. The board is releasably mounted by pressing it inwardly against the tabs in a manner causing the hook plates to extend through the board slots, and causing the board to depress a resilient latch member formed on the housing wall. The board is then slid along the tabs until the latch pops up and releasably locks the board to the contact tabs with the outer ends of the hook plates overlying the board. Small radiused outer ends of the hook plates bear against the board, along concentrated force areas, and function to press electrically conductive pads on the underside of the board against outer ends of the contact tabs. In molding the facing pairs of hook plates and contact tabs, small openings are formed therebetween in the housing wall. Pairs of opposing ribs on the housing wall form with the hook plate and contact tab pairs tunnels disposed around the housing wall openings and serving to substantially inhibit circuit board EMI/RFI emissions outwardly through the openings so that they need not be plugged or otherwise covered.

Claims

1. Apparatus for removably securing a printed circuit board to a computer housing wall, said apparatus comprising:

a spaced series of openings formed through the circuit board;

a spaced series of retention structures formed on a side of the housing wall and operative to removably hold the circuit board thereon in a parallel relationship therewith, each of said retention structures including;

first projecting means against which a side of the circuit board may be placed when the circuit board is laterally moved toward said housing wall side to a first parallel position relative thereto, and

second projecting means extendable through one of said circuit board openings in response to lateral movement of the circuit board to said first position thereof,

said first and second projecting means functioning to cooperatively and releasably bear against spaced opposite side surface portions of the circuit board, in response to edgewise movement of the circuit board from said first position thereof to a second position, in a manner releasably holding the circuit board in said second position thereof; and

cooperating means on said retention structures and the circuit board for facilitating an EMI/RFI grounding connection between the circuit board and the housing wall when the circuit board is in said second position thereof.

2. The apparatus of claim 1 wherein said cooperating means include:

an electrically conductive coating on the housing wall and said retention structures, and

a spaced series of electrically conductive pad members disposed on a side of the circuit board and positioned to be engaged by said first projecting means when the circuit is in said second position thereof.

3. Apparatus for removably securing a printed circuit board to a computer housing wall, said apparatus comprising:

a spaced series of openings formed through the circuit board;

a spaced series of retention structures formed on a side of the housing wall and operative to removably hold the circuit board thereon in a parallel relationship therewith, each of said retention structures including;

first projecting means against which a side of the circuit board may be placed when the circuit board is laterally moved toward said housing wall side to a first parallel position relative thereto, and

second projecting means extendable through one of said circuit board openings in response to lateral movement of the circuit board to said first position thereof,

said first and second projecting means functioning to cooperatively and releasably bear against spaced opposite side surface portions of the circuit board, in response to edgewise movement of the circuit board from said first position thereof to a second position, in a manner releasably holding the circuit board in said second position thereof,

each of said retention structures having an opening positioned between its first and second projecting means and extending through the housing wall, and further including projecting rib means formed on the housing wall and defining with the first and second projecting means a tunnel area communicating with the housing wall opening and serving to reduce EMI/RFI emissions from the secured circuit board outwardly through the housing wall opening.

4. A screwless method of removably mounting a printed circuit board on the inner side of a computer housing wall, said method comprising the steps of:

forming a spaced series of openings in the circuit board, each of said openings extending between first and second opposite sides of the circuit board;

forming a spaced series of retention structures on the inner side of the housing wall, each of said retention structures including spaced apart first and second portions projecting inwardly beyond the inner housing wall side;

laterally moving the circuit board, first side first, toward the inner housing wall side to a first position in which the first side of the circuit board engages said first retention structure portions, and said second retention structure portions extend through the circuit board openings past the second circuit board side;

moving the circuit board edgewise from said first position thereof to a second position in which the circuit board is frictionally and releasably gripped, on its opposite first and second sides, between said first and second portions of said retention structures;

conductively coating said first retention structure portions; and

forming a spaced apart series of electrically conductive pad areas disposed on the first side of the circuit board and positioned to be forcibly engaged by said first retention structure portions when the circuit board is in said second position thereof.

5. Computer apparatus comprising:

a computer housing having a generally flat wall with an inner side;

a spaced series of retention structures carried on said inner side of said housing wall, each of said retention structures including;

a hook plate member having a body portion extending generally transversely to said housing wall, and an outer end portion extending from said body portion generally parallel to said housing wall in a first direction, said outer end portion having a free end section extending toward said housing wall and terminating in a contact surface area, and

a contact tab member extending generally transversely to said housing wall and having an outer end surface spaced apart from said hook plate member contact surface area in said first direction and being offset from said contact surface area toward said housing wall,

said retention structures and said inner side of said housing wall being coated with an electrically conductive material;

a printed circuit board removably mounted on said retention structures, in a parallel relationship with said housing wall, said printed circuit board having a spaced series of slots formed therein and elongated in said first direction, said printed circuit board having a first side forcibly and slidably engaging said outer end surfaces of said contact tab members, and said hook plate members being removably extended through said slots with said outer end portions of said hook plate members overlying the second side of said printed circuit board and said contact surface areas of said hook plate members forcibly and slidably engaging said second side of said printed circuit board; and

electrically conductive contact pads carried on said first side of said printed circuit board and slidably engaged by said outer end surfaces of said contact tab members.

6. The computer apparatus of claim 5 wherein:

each of said contact surface areas has a relatively small, radiused shape and forcibly engages said second side of said printed circuit board in a concentrated point loading manner.

7. The computer apparatus of claim 5 wherein:

said printed circuit board is removable from said retention structures by sliding said printed circuit board in said first direction to position said hook plate member outer end portions over said slots and thereby permit the printed circuit board to be moved away from said housing wall as said hook plate member outer end portions pass through said slots.

8. Computer apparatus comprising:

a computer housing having a generally flat wall with an inner side;

a spaced series of retention structures carried on said inner side of said housing wall, each of said retention structures including;

a hook plate member having a body portion extending generally transversely to said housing wall, and an outer end portion extending from said body portion generally parallel to said housing wall in a first direction, said outer end portion having a free end section extending toward said housing wall and terminating in a contact surface area, and

a contact tab member extending generally transversely to said housing wall and having an outer end surface spaced apart from said hook plate member contact surface area in said first direction and being offset from said contact surface area toward said housing wall; and

a printed circuit board removably mounted on said retention structures, in a parallel relationship with said housing wall, said printed circuit board having a spaced series of slots formed therein and elongated in said first direction, said printed circuit board having a first side forcibly and slidably engaging said outer end surfaces of said contact tab members, and said hook plate members being removably extended through said slots with said outer end portions of said hook plate members overlying the second side of said printed circuit board and said contact surface areas of said hook plate members forcibly and slidably engaging said second side of said printed circuit board,

said housing wall, at each of said retention structures, having an opening formed therein between the hook plate and contact tab portions of the retention structure, and

said computer apparatus, at each of said retention structures, further comprises a pair of upstanding ribs formed on the inner side of said housing wall and forming with the hook plate and contact tab portions of the retention structure a tunneled extension of the wall opening to thereby inhibit EMI/RFI radiation emission from said printed circuit board outwardly through said housing wall opening.