System and method for retaining memory modules

The present invention is an apparatus and method for allowing for the use of commercial dual inline memory module (DIMM) in high shock and vibration environments while preserving serviceability. This system extends the performance of the standard Joint Electron Device Engineering (JEDEC) memory connectors in said environments without sacrificing high speed electrical performance. The system provides a simple clip which locks the module in place using the standard connector latches preventing relative motion of the connector and the DIMM thereby insuring uninterrupted computational performance. The clip may be formed with resilient ends that snap onto pivotal latching devices to prevent inadvertent opening of these latching devices. The clips may also include bumper spacers (205) on their opposite faces to engage bumper spacers of adjacent clips to maintain the modules in proper orientation.

FIELD OF THE INVENTION

The present invention generally relates to computers and electronic equipment, and more particularly relates to industrial and military computers, and even more particularly relates to methods and systems for providing rugged DIMM connections for use in demanding and hostile environments

BACKGROUND OF THE INVENTION

Server class compute platforms are typically not employed in environments that are harsh, such as military vehicles, construction vehicles, weapons platforms, space launch systems, and etc. These server platforms are becoming necessary because of the need for virtualization and compute density in smaller spaces. One of several obstacles requiring resolution is the fragility of the Joint Electron Device Engineering Council (JEDEC) style DIMM connector on these compute platforms. This connector is a high speed (electrical speeds in the 2-3 GHz range) interface using a leaf spring style contact which creates a line of surface electrical conduction where the spring side of the connector touches the circuit side of the DIMM via a gold plated pad on the circuit card. SeeFIG. 1.

When acceleration is imparted on the masses of the compute platform, the forces can exceed the contacts ability to maintain surface contact with the circuit card housing the memory chips. More frequently, the spring contact and the circuit card lose electrical connectivity when the chassis is distorted. This level of chassis deflection creates enough force to curve the motherboard, which drives the JEDEC latch up and the DIMM out of the connector, thereby creating a break in the electrical connectivity between the DIMM and the motherboard. The latch, which is designed to both retain the memory as well as extract the memory, is prone to creating a problem in shock and vibration. This is a particularly devastating event for these system architectures as they fail to operate normally thereafter until the connection is reestablished. Previous solutions have involved permanently bonding the DIMM into the connector of applying a retention band, which must be damaged on removal. The former is unserviceable while the latter requires depot repair.

Consequently, there exists a need for improved methods and systems for connecting JEDEC memory modules in a compute platform used in harsh environments, such as military vehicles, weapons platforms, and space launch systems, all done in a reliable and cost efficient manner.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a system and method for connecting memory modules via a DIMM connector in an efficient manner.

It is a feature of the present invention to utilize a retention clip.

It is an advantage of the present invention to reduce inadvertent disconnection of memory modules from a DIMM connector.

It is another feature of the present invention to include a bumper spacer between adjacent retention clips.

It is another advantage of the present invention to provide a self-alignment capability for a plurality of adjacent retention clips.

It is yet another feature of the present invention to have a tab on the ends of clip.

It is still another advantage of the present invention to further deter rotation of a connector latch.

It is still another feature to have a lid contacting surface on the retention clip.

It is still another advantage of the present invention to provide a lid induced clamping force on a connector latch.

It is yet another feature to include a memory module mounted retention clip.

It is still an advantage to reduce a possibility of loose pieces occurring inside the system.

The present invention is an apparatus and method for making more robust the connections between a memory module and a JEDEC style DIMM connector to satisfy the aforementioned needs, provide the previously stated objects, include the above-listed features, and achieve the already articulated advantages. The present invention is carried out in a “inadvertent latch rotation-less” manner in a sense that the likelihood, of an unwanted disconnection of a memory module has been greatly reduced.

Accordingly, the present invention is a system comprising:A system for reducing inadvertent disconnection of memory modules during operation in harsh environments comprising:a plurality of disconnection protected systems arranged in a parallel array; wherein each of said plurality of disconnection protected systems comprises:a DIMM connector120;a DIMM memory module110, having a memory module top edge108;a retention clip200having:a retention clip central portion208, having a retention clip first end202and retention clip second end204;a retention clip first angled portion212and retention clip second angled portion214disposed on opposing ends of said retention clip central portion208;a retention clip first latch engaging end222and a retention clip second latch engaging end224disposed on said retention clip first angled portion212and retention clip second angled portion214, respectively;said retention clip central portion208having a retention clip central portion top side209and a retention clip central portion bottom side207, which has a retention clip bottom side top edge receiving groove203disposed therein, which is configured to receive therein said memory module top edge108;a plurality of retention clip first face bumper spacers206;a plurality of retention clip second face bumper spacers205;a retention clip first latch engaging tab232disposed on an interior side of said retention clip first latch engaging end222;a retention clip second latch engaging tab234disposed on an interior side said retention clip second latch engaging end224facing said retention clip first latch engaging tab232; andwherein said array is spatially configured such that each retention clip200in said plurality of disconnection protected systems has at least one of said plurality of retention clip first face bumper spacers206and said plurality of retention clip second face bumper spacers205thereon in contact with one of said plurality of retention clip first face bumper spacers206and said plurality of retention clip second face bumper spacers205of another retention clip200of said plurality of disconnection protection systems.

Accordingly, the present invention is a method comprising the steps of:A method of reducing inadvertent disconnection of memory modules during operation in harsh environments comprising the steps of:providing a retention clip configured with a retention clip first latch engaging end222and a retention clip second latch engaging end224:installing a DIMM memory module110into a DIMM connector120having a first pivoting latch122and a second pivoting latch124; andengaging said retention clip with all of said DIMM memory module110; and engaging said retention clip first latch engaging end222and said retention clip second latch engaging end224with said first pivoting latch122and said second pivoting latch124, respectively.

DETAILED DESCRIPTION

Through this description details are given of a DIMM and a DIMM connector, it should be understood that different circuit cards with different types of electronic components could be used with different connector sizes and configurations. It is intended that these specific details not limit the scope of the present invention but instead fully enable a one specific and best mode of the invention and other variations of this card and connector types are intended to be readily understood from the following description and included within the scope and spirit of the present invention.

Now referring to the drawings wherein like numerals refer to like matter throughout, and more specifically referring toFIG. 1, there is shown a system of the prior art, generally designated100, including a prior art DIMM and connector100including a DIMM memory module110and a DIMM connector120. DIMM memory module110has a first end102, a second end104, a first end card notch112which provides a location for latching, a second end card notch114and a memory module top edge108. In a manner which is well known in the art, the DIMM memory module110is inserted into DIMM connector120, which cause first pivoting latch122and second pivoting latch124to rotate upwardly and latch at first end card notch112and second end card notch114, respectively. In such prior art systems the DIMM memory module110can be removed by pushing outwardly (moving away from each other) on an upper portion of first pivoting latch122and second pivoting latch124. If these upper portions are pushed away from each other simultaneously, the DIMM memory module110may be ejected from DIMM connector120into the air.

Now referring toFIG. 2, there is shown a retention clip200of the present invention, which comprises a retention clip first end202, retention clip second end204, a retention clip central portion208, which has a retention clip central portion top side209, a retention clip central portion bottom side207with a retention clip bottom side top edge receiving groove203therein. Retention clip central portion208has a retention clip first angled portion212and a retention clip second angled portion214, which are adjacent to retention clip first latch engaging end222and retention clip second latch engaging end224, respectively. Each of retention clip first angled portion212and retention clip second angled portion214has a memory module card corner receiving orifice213(FIG. 4) therethrough. Retention clip first latch engaging end222and retention clip second latch engaging end224have disposed thereon retention clip first latch engaging tab232and retention clip second latch engaging tab234, respectively. Retention clip central portion208further has retention clip second face bumper spacer205and retention clip first face bumper spacer206.

Retention clip200spans the longitudinal length of a standard JEDEC memory module such as DIMM memory module110, such that each end, retention clip first end202and retention clip second end204of the retention clip200, exerts through the retention clip first latch engaging end222and retention clip second latch engaging end224, respectively; an inward pressure on the insertion and extraction of each latch; first pivoting latch122and second pivoting latch124. The inward pressure is applied by retention clip200in such a way as to prevent rotation of first pivoting latch122and second pivoting latch124by exploiting the inherent tensile strength properties of the material from which it is constructed.

Key to the function of the retention clip200is the ability to flex around the first pivoting latch122and second pivoting latch124during the installation process of the DIMM memory module110into the DIMM connector120, but provide adequate resistance to the inherent latch rotation during chassis deflection, which often occurs during operation of the compute platform. The retention clip200therefore must be resistant to elongation in some areas but allow for flexure in the areas necessary for rotating around the latches during installation. This is in essence a snap-fit approach to retaining the DIMM in the connector. Retention clip200has spring-like properties and can be made of any suitable material which provides for minimal stretching and compression in the longitudinal direction, but with the ability for limited flexing, bending or bowing in directions other than the longitudinal direction.

Now referring toFIG. 3, there is shown a portion of disconnection protected system which includes an installed DIMM memory module110, in a DIMM connector120with a retention clip200. More specifically there is shown; the first pivoting latch122disposed in a latched orientation with the retention clip first latch engaging end222portion of the retention clip200applying a biasing force on the first pivoting latch122, which tends to keep the DIMM memory module110fully installed. Not visible in this Figure is retention clip first latch engaging tab232, which is present but concealing inside a slot in first pivoting latch122. A feature of the clip is the shape of the retention clip first latch engaging end222and retention clip second latch engaging end224, which interface with first pivoting latch122and second pivoting latch124. The angle of the retention clip200is designed to match that of the first pivoting latch122and second pivoting latch124such that a large force is required to allow rotation either latch.

Now referring toFIG. 4there is shown an additional view of the retention clip200. More visible inFIG. 4is retention clip bottom side top edge receiving groove203, which is configured to receive thereon a memory module top edge108. Memory module card corner receiving orifices213are clearly shown in retention clip first angled portion212and retention clip second angled portion214.

Now referring toFIG. 5, there is shown an upside down cross-sectional view of the retention clip200ofFIG. 4taken along retention clip central portion208at a point without a retention clip first face bumper spacer206of retention clip second face bumper spacer205. The diagonally hatched portion represents the material of retention clip central portion208which would be “cut” to allow this view to exist. A preferred embodiment of the retention clip200uses a “C” channel construction along an edge of the retention clip200to restrain motion of the DIMM memory module110in a lateral direction when installed in DIMM connector120.

Now referring toFIG. 6, there is shown side view of a first one of, and only shown one of, a parallel array of disconnection protected systems of the present invention in their intended environment including retention clip200. Edge of lid602is shown disposed over the first one but extends of all of the series of parallel systems each of which includes a retention clip200, DIMM memory module110and DIMM connector120such that the lid602contacts and applies a pressure on retention clip central portion top side209for each of this series of retention clips200. First pivoting latch122and second pivoting latch124are shown in a latched configuration with the retention clip200applying inward force therein which resists disconnection inducing rotation of the first pivoting latch122and second pivoting latch124. In this preferred embodiment, the retention clip200would also contain a feature which created contact with some removable chassis structure to prevent motion of a rotational nature. In the description herein, this structure is the lid602or cover of the chassis. Having this structural interference with the retention clip200prevents rotation of first pivoting latch122and second pivoting latch124and insures connectivity of the memory circuits, however this interference is not required to make the innovation useful. A similar example of this feature is a simple curvature of the retention clip central portion208such that the lid applies force to the retention clip first latch engaging end222and retention clip second latch engaging end224. Since the material has some spring characteristics, the contact with the lid602creates a force on the ends of first pivoting latch122and second pivoting latch124, which further secures the DIMM memory module110into the DIMM connector120.

Now referring toFIG. 7, there is shown an alternate version of the present invention which includes buttressed retention clip700, which is similar in many respects to retention clip200and which also includes first end lid contacting buttress702and second end lid contacting buttress704which can transmit force from the lid602to the first pivoting latch122and second pivoting latch124to provide additional biasing forces to prevent inadvertent rotation of the first pivoting latch122and second pivoting latch124. Additionally, a feature of the buttressed retention clip700is to capture the memory module top edge108near the jes602to resist lateral motion of the DIMM memory module110either through the resistance of the buttressed retention clip700to deflect laterally or by pressure applied by the lid602.

Now referring toFIG. 8, there is an alternate view of the retention clip200, but from a more downwardly looking viewpoint.

Now referring toFIG. 9, there is shown an upwardly looking view, of a parallel array of retention clips200which shows retention clip bottom side top edge receiving groove203and it also shows how a retention clip second face bumper spacer205of first parallel retention clip992contacts a retention clip first face bumper spacer206of second parallel retention clip994, which helps to prevent lateral motion of the DIMM memory module110. An additional feature of the retention clip200or buttressed retention clip700is to provide a self-aligning feature that allows for proper lateral spacing of the clips. This feature would be in the form of tapered retention clip second face bumper spacers205and retention clip first face bumper spacer206in the most obvious example, which guided one clip which was adjacent to another clip, such that alignment of second clip was optimum for installation on the second DIMM memory module.

Now referring toFIG. 10, there is shown a close up view of the retention clip first end202, which includes retention clip first latch engaging tab232which is on an interior side of retention clip first latch engaging end222and is designed to fit into a slot in first pivoting latch122during installation. The slot is present as a feature for the operation of the extraction and insertion action. The purpose of the retention clip first latch engaging tab232and retention clip second latch engaging tab234is to further deter rotation of the latch mechanism of the DIMM connector120by preventing upward motion on the retention clip200, thereby separating it from the DIMM memory module110and DIMM connector120pair.

Now referring toFIG. 11, there is shown an alternative feature of the present invention, which includes: member for transmitting latch effecting forces1110with a top surface1111. Member for transmitting latch effecting forces1110is connected to DIMM memory module110via module mounting structure1120, which can be a rivet, peg or other structure which may or may not permit rotation of the member for transmitting latch effecting forces1110thereabouts. Latch engaging structure1130is similar in design and function to retention clip second latch engaging end224. An additional advantage of this feature of the invention is to attach the retention clips directly to the memory modules using the JEDEC specified standard hole pattern on the module to fix the clip directly to the module using a pin or a rivet type of fastener, thereby eliminating loose pieces in the system.

Throughout this description, reference is made to an industrial PC and to a printed circuit board, because it is believed that the beneficial aspects of the present invention would be most readily apparent when used in connection with industrial PCs and printed circuit boards; however, it should be understood that the present invention is not intended to be limited to industrial PCs and printed circuit boards and should be hereby construed to include other non-industrial PCs and non-printed circuit boards as well.

It is thought that the method and apparatus of the present invention will be understood from the foregoing description and that it will be apparent that various changes may be made in the form, construct steps, and arrangement of the parts and steps thereof, without departing from the spirit and scope of the invention or sacrificing all of their material advantages. The form herein described is merely a preferred exemplary embodiment thereof.