Retention mechanism and electronic module mounting system

[0002] The present invention relates generally to mounting electronic components to a motherboard, and more particularly to mounting brackets with heat sinks and in particular to grounding a heat sink using an electromagnetic interference (EMI) retention module.

[0003] For a variety of reasons most electronic systems are modular in design. Different aspects or functions of a system are implemented on different circuit boards, thus allowing systems of varying degrees in functionality to be easily put together by including or excluding certain circuit boards. Modularity also allows systems to be easily upgraded with additional functions by adding or replacing certain circuit boards. Often, one of the circuit boards is considered to be the main circuit board, to which all the other circuit boards are connected. The main circuit board is often referred to as the backplane or the motherboard, whereas the other circuit boards are often referred to as the add-on boards/cards or daughter cards. For example, in the case of personal computers the circuit board where the main components such as the processor and the memory are mounted is often considered the motherboard. The expansion or optional functions, such as serial/parallel interfaces, game adapters, graphics and/or video adapters, network adapters, and modems, are implemented using add-on/daughter cards, which are connected to the expansion slots or connectors of the motherboard. However, in recent years, the role of the expansion slots/connectors is beginning to blur, as manufacturers begin to package processors and memory components on daughter cards, also referred to as processor cards.

[0004] A result of the increased heat dissipation and electromagnetic interference (EMI) shielding requirements of the newer high speed processors, continuous improvement in processor card design has been a goal of computer system designers.

[0005] According to one embodiment of the invention, there is provided a retention mechanism formed of a molded plastic member having a base portion with at least one through-hole and a first through-slot adjacent thereto. The plastic member includes a card receiving structure having an open side, and a second receiving structure having an open side with a second through-slot through a wall of the receiving structure perpendicular to the base portion. Inserted in the plastic member is an elongate metal member having a base portion and a distal end. The metal member extends through the first and second through-slots with the base portion positioned adjacent the base portion and the distal portion positioned within the second receiving structure. The distal portion of the metal member is formed to provide spring action against a member inserted into the second receiving structure.

[0006] FIGS. 1-7 illustrate an embodiment of the retention mechanism according to the present invention.

[0007] FIGS. 8-9 illustrate an embodiment of a mounting system according to the present invention.

[0008] In the following detailed description of the invention reference is made to the accompanying drawings which form a part hereof, and in which is shown, by way of illustration, specific embodiments in which the invention may be practiced. In the drawings, like numerals describe substantially similar components throughout the several views. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the present invention.

[0009] Referring now to FIGS. 1-7, there is illustrated a first embodiment of a retention mechanism 10 according to the present invention. As illustrated, retention mechanism 10 is formed of a molded plastic member 12 having base portions 14aand 14bwith a through-hole 16awith a first through-slot 18 adjacent thereto through portion 14a, and a through-hole 16bthrough portion 14b. Member 12 includes a printed circuit board module receiving structure 20 with an open side or face, and a heat sink receiving structure 24 having an open side or face with a second through-slot 28 through a wall 30 of the receiving structure 24 parallel to the bottom surface 15 of base portions 14aand 14b. Molded reinforcing ribs 25 are used to strengthen the heat sink receiving structure 24. A latching surface 27 is provided to catch and retain an edge of a member inserted therein, as described more fully below.

[0010] An elongate metal member 32 is inserted in the member 12. It includes a base portion 34 and a distal portion 36, and extends through the first and second through-slots 18 and 28 with the base portion 34 positioned adjacent the base portion 14aof the member 12 and the distal portion 36 positioned within the second receiving structure 24. The distal portion 36 of the metal member is formed to provide spring action of approximately five ounces, in one example embodiment, against a heat sink member inserted into the receiving structure 24. As illustrated in particular in FIG. 3, the receiving structure 24 includes a through-slot 38 on a wall 40 thereof, which is spaced longitudinally away from the through-slot 28. The distal portion 36 of member 32 includes a distal end 42 passing through the through-slot 38.

[0011] According to one embodiment, the metal member 32 is substantially flat in cross section and the distal portion 36 includes bend 44 and bend 46 to provide spring action. The base portion 34 includes a through-hole 48 which is aligned with the through-hole 16 and formed to lie flat against a bottom surface of the base portion 14aof the member 12.

[0012] Referring now to FIGS. 8-9, there is illustrated a retention system 50. System 50 includes a pair of retention mechanisms 10 mounted to a printed circuit board 52, for example a motherboard, with fastenal fasteners 54aand 54b, which pass through holes 16aand 16b, and the corresponding respective through-holes 48 of the metal members 32 in each mechanism. Fasteners 54aand 54bare screwed into corresponding holes in board 52. As illustrated, the retention mechanisms 10 are mounted spaced apart and facing one another on the printed circuit board 52, and with the base portions of the metal members 32 sandwiched between the base portions 14aand 14bof the retention mechanism 10 and the printed circuit board 52. Grounding pads are provided on the board 52 directly underneath where end 34 of member 32 engages the board 52. The ground pads provide an electrical path to the board's ground circuit, in order to suppress EMI from the electronic module 60. The printed circuit board 52 further includes a female edge connector 59 mounted to the board in-between the retention mechanisms 10. Further, in one embodiment, retention mechanisms 10 are mounted on the board 52 so as to tilt inward toward each other approximately 3.2 degrees from an axis orthogonal to the board 52, to apply a compressive force to the ends of a heat sink member 66 when it is inserted.

[0013] As illustrated, an electronic module 60 includes a printed circuit board 76, a shield 61, and a heat sink and EMI shielding member 66. The circuit board 76 includes a male edge connector 76athat is inserted in the connector 59. Heat sink or EMI shield member 66 has ends 68aand 68bthat are inserted in the receiving structure 24. According to this embodiment, the ends 68aand 68bare each portions of a metal plate or other conductive structure that act against the spring action of the metal members 32 to hold the metal members 32 and the ends in electrical contact with one another. As also illustrated, in one embodiment, the module 60, for example a processor module, includes heat dissipation prongs 74. When inserted in the retention mechanisms 10, an edge 71 catches an surface 27, to keep the module 60 latched in place. member 32 and connecting the other end of the metal member 32 to the printed circuit board 52 by sandwiching it between the printed circuit board 52 and the retention mechanism 10 supporting the electronic module 60.

[0014] Retention mechanism 10 may be molded from any suitable plastic or other material. Metal member 32 can be formed from any suitable metal or other material. However, the invention is in no way limited in these respects.

[0015] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover any adaptions or variations of the present invention. Therefore, it is manifestly intended that this invention be limited only by the claims and equivalents thereof.