LGA socket having improved standoff

An LGA socket includes an insulative housing, a number of conductive terminals received retained in the housing, a stiffener surrounding the insulative housing, a load plate and a load lever pivotally assembled to the stiffener, and a locking mechanism. The locking mechanism includes a screw attached to the stiffener in a horizontal direction and a washer attached to the support plate in a vertical direction. The locking mechanism is attached to the stiffener before the LGA socket mounting to a printed circuit board.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a socket, on which an LGA (land grid array) integrated circuit (IC) package is mounted.

2. Description of Related Art

Modern computer systems increase in performance and complexity at a very rapid pace, driven by intense competition and market demands. In order to meet ever-increasing performance requirements, the area and volumetric interconnect densities of electronic board assemblies must increase accordingly. In combination with other competitive forces, this demand has driven the need for improved high-density socket technologies in computer applications, and the connector industry has responded with a variety of new alternatives to meet these needs. One of the most attractive of the new connector types is the land grid array (LGA) socket, which permits direct electrical connection between an LGA integrated circuit and a printed circuit board. LGA sockets are an evolving technology in which an interconnection between mating surfaces of an IC or other area array device and a printed circuit board is provided through a conductive terminal received in the socket. Connection is achieved by mechanically compressing the IC onto the socket.

A typical type of socket for carrying an IC package and electrically connecting the IC package to a circuit board, e.g. a PCB comprises a metallic stiffener, an insulative housing, a load plate, a load lever and a plurality of plastic supporting posts. The stiffener defines a central opening in a middle portion thereof, the opening being surrounded by two pairs of inner surfaces. The housing defines a recessed conductive zone surrounded by sidewall. The stiffener defines a plurality of through holes on four corners thereof. The plastic supporting posts are partially received in the through holes and arranged between the stiffener and the circuit board. A plurality of screws passes through the through holes for mounting the stiffener onto the circuit. The plurality of plastic supporting posts is used for separating the stiffener from the circuit board; therefore the stiffener is easily removed. Apparently, the plastic supporting posts don't carry function of attachment stiffener to the circuit board and mechanical connection between the stiffener and the circuit board is unsteady.

Another type of LGA socket is provided with captive screws in different configuration and assemblies with captive components. The screws are mounted to the circuit board for securing the stiffener on the circuit board. During the product shipment and assembly, the screws are apart from the stiffener. Therefore, when system manufactures assemble the LGA socket to the circuit board, the screws are easily lost on the board and the time is increased on assembly. Furthermore, it is not acceptable for high cost per special screw.

Accordingly, there is a room for improving the existing socket such that the cost and the assembly time are reduced.

BRIEF SUMMARY OF THE INVENTION

An LGA socket comprising an insulative housing defining a conductive region surrounded by two pairs of sidewalls, a plurality of conductive terminals received in the conductive region, a stiffener surrounding the insulative housing, a load plate and a load lever pivotally assembled to the stiffener, and a locking mechanism. The stiffener includes a plurality of support plates at corners thereof and each support plate defines a side-opening slot. The locking mechanism includes a screw attached to the slot in a horizontal direction and a washer attached to the support plate in a vertical direction. The washer is provided with a through hole for the screw pass through.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, a preferred embodiment of the invention will be described in detail with reference to the attached drawings.

Referring toFIG. 1, an LGA socket100for carrying an IC package (not shown) to be electrically connected to a printed circuit board (not shown). The LGA socket100comprises an insulative housing10, a metallic stiffener20surrounding the insulative housing10, a plurality of conducive terminals11received in the insulative housing10, a load plate30pivotally assembled to one end of the stiffener20, a load lever40pivotally assembled to the other end of the stiffener20, and a locking mechanism attached to the stiffener20.

The insulative housing10defines a recessed conductive region12surrounded by two pairs of sidewalls13. The terminals11are fixed in the conductive region12.

The metallic stiffener20is formed by stamping form a metallic sheet. The stiffener20defines an opening21in a middle portion thereof for receiving the insulative housing10. The opening21is generally rectangular and is surrounded by two pairs of bottom plates22. The stiffener20defines a first end201and a second end202separated by the opening21. The stiffener20comprises a plurality of support plates23at corners thereof and surrounding the opening21. Each support plate23defines a side-opening slot231. In this embodiment, the slots231are arranged at four corners of the stiffener20. The stiffener20defines an upper surface203and a lower surface204opposite to the upper surface203. The slots231extend through the upper surface203and the lower surface204in a vertical direction. The support plate23further defines a cutout232communicated with the slot231. In this embodiment, the sidewalls13of the insulative housing10are interferentially engaged with the opening21. Furthermore, in an alternative embodiment, the insulative housing can be surrounded by the opening but without interference therebetween.

The load plate30is generally rectangular and includes a rear end31, a front end32and two opposed pressing beams33,34connected therewith. The load lever40is generally L-shaped, and comprises a pivotal section41, a pressing section42protruding from the pivotal section41, and an operating section43extending form a distal end of the pivotal section41. In assembly, the load plate30and the load lever40are received in opposite ends of the stiffener20, respectively.

Referring toFIGS. 2-6, the locking mechanism including a screw50attached to the slot231of the support plate23in a horizontal direction, a washer60attached to the support plate30in a vertical direction, and a gasket70secured between the screw50and the support plate23. The washer60is provided with a close through hole61for the screw50pass through in a vertical direction. The washer60defines a flat bottom surface601projecting downwardly from the support plate23and a top surface602opposite to the bottom surface601. The washer60comprises a plurality of snapped sections62for engaging with the support plate23, a first protrusion63received in the side-opening slot231, and a second protrusion64received in another hole233of the support plate23.

The screw50comprises a head51supported on the support plate23at one end and a cylindrical shaft52at other end with a thread23formed thereon. The diameters of the head51and the thread53are more than the diameter the cylindrical shaft52. The diameter of the slot231on the support plate23is less than the diameter of the thread53of the screw50. The length of the cut-out232is substantially equal to the diameter of the screw50so that the screw50can be inserted into the slot231through the cut out232. The screw50is movably along the vertical direction and is limited in a horizontal plane. In assembly, push the screw50into support plate23through the cut out232, then install stand-off washer50to capture and secure the screw50on the support plate23.

Referring toFIG. 7, an LGA socket100′ according to a second embodiment of the present invention comprises an insulative housing10′, a metallic stiffener20′ surrounding the insulative housing10′, a plurality of conducive terminals11′ received in the insulative housing10′, a load plate30′ pivotally assembled to one end of the stiffener20′, a load lever40′ pivotally assembled to the other end of the stiffener20′, and a locking mechanism attached to the stiffener20′. The structure of the socket100′ is similar to the first embodiment except the latch mechanism.

The insulative housing10′ defines a recessed conductive region12′ surrounded by two pairs of sidewalls13′. The terminals11′ are fixed in the conductive region12′.

The metallic stiffener20′ is formed by stamping form a metallic sheet. The stiffener20′ defines an opening21′ in a middle portion thereof for receiving the insulative housing10′. The opening21′ is generally rectangular and is surrounded by two pairs of bottom plates22′. The stiffener20′ comprises a plurality of support plates23′ at corners thereof and surrounding the opening21′. Each support plate23′ defines a side-opening slot231′. The stiffener20′ defines an upper surface203′ and a lower surface204′ opposite to the upper surface203′. The slots231′ extend through the upper surface203′ and the lower surface204′ in a vertical direction. The support plate23′ further defines a cut-out232′ communicated with the slot231′ at an outer side thereof and a notch233′ at an inner side thereof.

Referring toFIGS. 8-11, the locking mechanism including a screw50′ attached to the slot231′ of the support plate23′ in a horizontal direction, a top washer62′ attached to the support plate30′, and a bottom washer61′ secured between the screw50′ and the support plate23′. The top and bottom washers62′,61′ are attached to the support plate23′ in a vertical direction and engage with each other. The top and bottom washers62′,61′ each are provided with a close through hole64′,63′ for the screw50′ passing through in a vertical direction. The bottom washer61′ defines a flat bottom surface601′ projecting downwardly from the support plate23′. The bottom washer61′ comprises a plurality of snapped sections66′ for locking with the top washer62′. The bottom washer61′ further includes a plurality of retaining sections65′ adjacent to the snapped sections232′ and received in the notches233′ thereby capturing the support plate23.

The screw50′ comprises a head51′ supported on the support plate23′ at one end and a cylindrical shaft52′ at other end with a thread23′ formed thereon. The diameters of the head51′ and the thread53′ are more than the diameter the cylindrical shaft52′. The diameter of the slot231′ on the support plate23′ is less than the diameter of the thread53′ of the screw50′. The length of the cut-out232′ is substantially equal to the diameter of the screw50′ so that the screw50′ can be inserted into the slot231′ through the cut out232′. The screw50′ is movably along the vertical direction and is limited in a horizontal plane. In assembly, push the screw50′ into support plate23′ through the cut-out232′, then install the top and bottom washers62′,61′ to capture and secure the screw50on the support plate23.

The screw50,50′ is a standard captive screw without additional components so that ODMS need not to deal with the screw suppliers. The cost of the screws can be reduced. Furthermore, the screws50,450′ are attached to the stiffener20during product shipment and before mount to PCB. Therefore, not only simplify the assembly line process but also reduce the assembly time. In the present invention, the washer60,61′ also work as a stand-off from the PCB side and keep the LGA socket on the PCB. Although, the stiffener of the present invention is an intergrated configuration, it also could be a plurality of separated parts and the support plates are formed on the separated parts.