Patent Publication Number: US-8979561-B2

Title: Interleaving ejector latches enabling a reduced end-to-end spacing between memory module connectors

Description:
BACKGROUND 
     1. Field of the Invention 
     The present invention relates to the ejector latches used with memory module connectors to secure memory modules. 
     2. Background of the Related Art 
     Card edge connectors are used in computers and other electronic devices for establishing an electrical connection between a main printed circuit board (PCB) and a supporting PCB. The main PCB may be a motherboard, and the supporting PCB may be a daughter card. For example, a Dual In-line Memory Module (DIMM) card may be received in a DIMM socket connector mounted on a motherboard of a computer or other information technology equipment. 
     A memory module connector includes a housing having a slot for physically receiving the card and electrical contacts to provide electrical connections between the card and the motherboard. The memory module connector may include an ejector latch is used to latch the memory module in position and assist in removal of the memory module from the connector. 
     Motherboards will often include multiple memory module connectors. These memory module connectors may be arranged side-by-side in to form a first set, but some motherboards will even have memory module connectors arranged end-to-end. For example, a motherboard may have a first set of memory module connectors arranged side-by-side and a second set of memory module connectors arranged side-by-side, where the memory module connectors in the first set have one end that is directly adjacent and aligned with one end of the memory module connectors in the second set. 
     For a given motherboard, the memory module connectors are typically arranged to maintain proper airflow for cooling of the memory modules. For example, DIMMs are usually grouped closely together and are oriented parallel to the airflow for optimum cooling and even airflow distribution. 
     BRIEF SUMMARY 
     One embodiment of the present invention provides an apparatus comprising a printed circuit board securing first and second memory module connectors in end-to-end alignment, wherein the first memory module connector has a first slot configured to receive a first memory module and the second memory module connector has a second slot configured to receive a second memory module, and wherein the first and second memory modules are centered on a common plane. The first memory module connector has a first ejector pivotally coupled to a first end of the first memory module connector about an axis perpendicular to the plane, wherein the first ejector has an upper arm extending from the pivot axis away from the printed circuit board and a lower arm extending from the pivot axis under the first slot, and wherein a distal portion of the upper arm of the first ejector lies only on a first side of the plane. The second memory module connector has a second ejector pivotally coupled to a second end of the second memory module connector about an axis perpendicular to the plane, wherein the second ejector has an upper arm extending from the pivot axis away from the printed circuit board and a lower arm extending from the pivot axis under the second slot, and wherein a distal portion of the upper arm of the second ejector lies only on a second side of the plane. The first end of the first memory module connector is separated by a narrow gap from the second end of the second memory module connector. Pivoting of the first ejector from a closed position to an open position causes the distal portion of the upper arm of the first ejector to interleave with the distal portion of the upper arm of the second ejector, and pivoting of the second ejector from a closed position to an open position causes the distal portion of the upper arm of the second ejector to interleave with the distal portion of the upper arm of the first ejector. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a plan view of a server motherboard having memory module connectors arranged side-by-side and end-to-end. 
         FIG. 2  is a perspective view of first and second ejector latches that facilitate close end-to-end spacing between two memory module connectors. 
         FIG. 3A  is a partial cross-sectional side view of a memory module connector and ejector latch securing a memory module in electrical communication with the memory module connector. 
         FIG. 3B  is a partial cross-sectional side view of a memory module connector and ejector latch as in  FIG. 3A , but with the ejector latch in an open position for installation or removal of the memory module. 
         FIGS. 4A and 4B  are side views of the first and second ejector latches in  FIG. 2  showing how the ejector latches may be pivoted to an open position with one ejector latch interleaving with the other. 
         FIGS. 5A-5B  are top views of the first and second ejector latches. 
         FIGS. 6A-6D  are a series of side views of the first and second ejector latches showing how bumpers are used to close one ejector latch as another ejector latch is opened. 
     
    
    
     DETAILED DESCRIPTION 
     One embodiment of the present invention provides an apparatus comprising a printed circuit board securing first and second memory module connectors in end-to-end alignment, wherein the first memory module connector has a first slot configured to receive a first memory module and the second memory module connector has a second slot configured to receive a second memory module, and wherein the first and second memory modules are centered on a common plane. The first memory module connector has a first ejector pivotally coupled to a first end of the first memory module connector about an axis perpendicular to the plane, wherein the first ejector has an upper arm extending from the pivot axis away from the printed circuit board and a lower arm extending from the pivot axis under the first slot, and wherein a distal portion of the upper arm of the first ejector lies only on a first side of the plane. The second memory module connector has a second ejector pivotally coupled to a second end of the second memory module connector about an axis perpendicular to the plane, wherein the second ejector has an upper arm extending from the pivot axis away from the printed circuit board and a lower arm extending from the pivot axis under the second slot, and wherein a distal portion of the upper arm of the second ejector lies only on a second side of the plane. The first end of the first memory module connector is separated by a narrow gap from the second end of the second memory module connector. Pivoting of the first ejector from a closed position to an open position causes the distal portion of the upper arm of the first ejector to interleave with the distal portion of the upper arm of the second ejector, and pivoting of the second ejector from a closed position to an open position causes the distal portion of the upper arm of the second ejector to interleave with the distal portion of the upper arm of the first ejector. 
     The printed circuit board may take any form, but is preferably a motherboard of a server or other computer or information technology equipment. Furthermore, the first memory module connector may be in a first side-by-side set of memory module connectors and the second memory module connector may be in a second side-by-side set of memory module connectors. In such a configuration, there may be multiple instances of end-to-end memory module connectors. It should be recognized that the invention may be implemented in each instance of memory module connectors that are aligned end-to-end. 
     The first memory module connector may be described as having a body that forms the first slot, and the first end of the first memory module connector may take the form of a tower that extends further from the printed circuit board than the body. The first ejector may have a pair of side pins that are received within mating holes in the tower to allow the first ejector to pivot about an axis perpendicular to the plane. Similarly, the second memory module connector may be described as having a body that forms the second slot, and the second end of the second memory module connector may take the form of a tower that extends further from the printed circuit board than the body. Furthermore, the second ejector may have a pair of side pins that are received within mating holes in the tower to allow the second ejector to pivot about an axis perpendicular to the plane. 
     The narrow gap separating the first end of the first memory module connector from the second end of the second memory module connector is preferably a distance less than 22 millimeters, and more preferably 15 millimeters or less. 
     Pivoting of the first ejector from a closed position to an open position causes the distal portion of the upper arm of the first ejector to interleave with the distal portion of the upper arm of the second ejector, and pivoting of the second ejector from a closed position to an open position causes the distal portion of the upper arm of the second ejector to interleave with the distal portion of the upper arm of the first ejector. The first and second ejectors may also interleave when both ejectors are in an intermediate position. 
     In one embodiment, the upper arm of the first ejector may include a first bumper extending toward the second ejector and aligned for engagement with the upper arm of the second ejector. Similarly, the upper arm of the second ejector may include a second bumper extending toward the first ejector and aligned for engagement with the upper arm of the first ejector. In embodiments having first and second bumpers, the first bumper preferably lies only on the second side of the plane and the second bumper preferably lies only on the first side of the plane. Alternatively, the first bumper could be made to lie only on the first side of the plane and the second bumper could be made to lie only on the second side of the plane. 
     One or more bumper may be implemented so that pivoting the first ejector from the closed position toward the open position will, if the second ejector is in the open position, cause the second ejector to pivot toward the closed position. Preferably, the one or more bumper may be implemented to further include the feature that pivoting the second ejector from the closed position toward the open position will, if the first ejector is in the open position, cause the first ejector to pivot toward the closed position. Most preferably, the first and second memory module connectors are arranged end-to-end with a narrow gap such that only one of the first and second ejectors can be in an open position at a time. Still further, a distal end of the upper arm of the first ejector may extend over the second end of the second memory module connector when the first ejector is in the open position, and a distal end of the upper arm of the second ejector may extend over the first end of the first memory module connector when the second ejector is in the open position. 
     In a further embodiment, the lower arm of the first ejector selectively assists removal of the first memory module from the first slot in response to pivoting of the upper arm of the first ejector away from the first memory module, and the lower arm of the second ejector selectively assists removal of the second memory module from the second slot in response to pivoting of the upper arm of the second ejector away from the second memory module. 
     In a still further embodiment, the first ejector may include a first tab extending from the upper arm of the first ejector, wherein the first tab is configured to be received into a notch in an edge of the first memory module when the first ejector is in the closed position. Similarly, the second ejector may include a second tab extending from the upper arm of the second ejector, wherein the second tab is configured to be received into a notch in an edge of the second memory module when the second ejector is in the closed position. Such a tab secures a memory module from being removed or dislodged while the corresponding ejector is in the closed position. 
     The upper arm of the first ejector preferably has a distal end forming a concave finger grip, and the upper arm of the second ejector preferably has a distal end forming a concave finger grip. The concave finger grip is beneficial to the ease of use of an ejector, since the gap between the first and second memory module connectors is very narrow. Accordingly, there is very little room between two installed memory modules for a user to operate the ejector and cause the upper arm of the ejector to pivot away from memory module. A concave finger grip on the distal end of the upper arm of an ejector allows a user&#39;s finger tip to push the upper arm toward the open position or the closed position. The further simplify use of the ejectors in the narrow gap between memory module connectors, a distal end of the upper arm of the first ejector preferably extends away from the printed circuit board to substantially the same elevation as a top edge of the first memory module when the first memory module is installed in the first memory module connector and the first ejector is in the closed position. Similarly, a distal end of the upper arm of the second ejector preferably extends away from the printed circuit board to substantially the same elevation as a top edge of the second memory module when the second memory module is installed in the second memory module connector and the second ejector is in the closed position. 
       FIG. 1  is a plan view of a server  10  with a motherboard  12  having memory module connectors  20  arranged side-by-side and end-to-end. In the example motherboard  12  as shown, the memory module connectors are arranged in four different sets  14 ,  15 ,  16 ,  17  of memory module connectors, with six side-by-side memory module connectors  20  in each set. Each of the individual memory module connectors in a first set  14  are aligned end-to-end with one of the individual memory module connectors in a second set  15 , and each of the individual memory module connectors in a third set  16  are aligned end-to-end with one of the individual memory module connectors in a fourth set  17 . A gap  18  exists between the end-to-end memory module connectors for operating ejectors  30 A,  30 B. 
       FIG. 2  is a perspective view of first and second ejector latches  30 A,  30 B that facilitate close end-to-end spacing between first and second memory module connectors  20 A,  20 B. In the optional embodiment shown, the first and second memory module connectors  20 A,  20 B, as well as the first and second ejector latches  30 A,  30 B, are identical to each other, but oriented  180  degrees from each other and aligned end-to-end. Accordingly, the description of a first memory module connector  20 A is equally applicable to a second memory module connector  20 B and the description of a first ejector latch  30 A is equally applicable to a second ejector latch  30 B. 
     The first memory module connector  20 A is secured to the printed circuit board  12  and provides a slot  22 A for receiving the edge of a first memory module  24 A. The first memory module connector  20 A also includes a tower  26 A at the end of the first memory module connector  20 A. The tower  26 A receives and pivotally secures the first ejector latch  30 A so that the first ejector latch  30 A may pivot about an axis  28 A between a closed/latched position (as shown) and an open/unlatched position. 
     The first ejector latch  30 A includes an upper arm  31 A extending upward from the pivot axis  28 A and includes a finger grip  32 A, a bumper  33 A, and a tab  34 A. The finger grip  32 A allows a finger to easily move the upper arm  31 A away from the first memory module  24 A, such that the ejector latch  30 A pivots from the closed position (as shown) to the open position. The bumper  33 A extends toward the second ejector latch  30 B and may be used to limit the range of motion of the first ejector latch  30 A and push the second ejector latch  30 B toward a closed position if the second ejector latch  30 B was left in an open position. The interaction between the first and second ejector latches  30 A,  30 B is described in more detail below. A tab  34 A is also provided on the upper arm  31 A and extends toward the slot  22 A and is positioned to align with, and be received in, a notch  25 A that is formed in the edge of the first memory module  24 A. Accordingly, when the first ejector latch  30 A is in the closed position (as shown), the tab  34 A is received in the notch  25 A and prevents removal of the first memory module  24 A from the first memory module connector  20 A. Optionally, the first ejector latch  30 A remains in the closed position under frictional forces with the tower  26 A and by interference with the lower edge of the first memory module  24 A (see  FIG. 3A ). 
       FIG. 3A  is a partial cross-sectional side view of a memory module connector  20 A and ejector latch  30 A securing a memory module  24 A in a position for electrical communication with other components (see  FIG. 1 ) that are also installed on the printed circuit board  12 . The ejector latch  30 A has a pair of opposing pins  35 A that are received in mating holes within the tower  26 A to allow the ejector latch  30 A to pivot about the axis  28 A that is defined by the position of the holes. The ejector latch  30 A also includes a lower arm  36 A that extends from the pivot axis  28 A under the first memory module  24 A. With the ejector latch  30 A in the closed position of  FIG. 3A , the first memory module  24 A may be fully seated in the slot of the first memory module connector  20 A. 
       FIG. 3B  is a partial cross-sectional side view of the first memory module connector  20 A and the first ejector latch  30 A as in  FIG. 3A , but with the ejector latch  30 A in an open position for installation or removal of the first memory module  24 A. In the open position, the tab  34 A has withdrawn from the notch  25 A to allow the first memory module  24 A to be removed, and the lower arm  36 A has lifted upward against the lower edge of the first memory module  24 A. This is how the ejector latch  30 A is used to assist in removing a memory module. 
       FIGS. 4A and 4B  are side views of the first and second ejector latches  30 A,  30 B in  FIG. 2  showing how the ejector latches may be pivoted to an open position with one ejector latch interleaving with the other.  FIG. 4A  illustrates that the first ejector latch  30 A may be pivoted (clockwise, as shown) away from the first memory module  24 A to an open position (shown in dashed lines). In the open position, a distal end of the upper arm  31 A of the first ejector latch  30 A interleaves with the upper arm  31 B of the second ejector latch  30 B. Aspects of the interleaving ejector latches  30 A,  30 B are discussed further below in reference to  FIGS. 5A-B . Furthermore, the bumper  33 B of the second ejector latch  30 B is shown in contact with the first ejector latch  30 A. Aspects of the bumpers  33 A,  33 B are discussed further below in reference to  FIGS. 6A-D . 
       FIG. 4B  illustrates that the second ejector latch  30 B may be pivoted (counter-clockwise, as shown) away from the second memory module  24 B to an open position (shown in dashed lines). In the open position, a distal end of the upper arm  31 B of the second ejector latch  30 B interleaves with the upper arm  31 A of the first ejector latch  30 A. Furthermore, the bumper  33 A of the first ejector latch  30 A is shown in contact with the second ejector latch  30 B. 
       FIG. 5A  is a top view of the first and second ejector latches  30 A,  30 B with both ejector latches in the closed position, consistent with  FIG. 2 . Accordingly, the first ejector latch  30 A has its tab  34 A received in the notch of the first memory module  24 A to secure the first memory module in the slot of the first memory module connector  20 A. Similarly, the second ejector latch  30 B has its tab  34 B received in the notch of the second memory module  24 B to secure the second memory module in the slot of the second memory module connector  20 B. 
     With the first and second memory module connectors  20 A,  20 B in end-to-end alignment, the first and second memory module connectors  20 A,  20 B are centered along a central plane  40  (shown in dashed lines). As a result, the first and second memory modules  24 A,  24 B are installed along the plane  40  and the first and second ejector latches  30 A,  30 B pivot about their axis  28 A,  28 B, respectively. The pivot axis  28 A,  28 B are substantially perpendicular to the plane  40 , such that the first and second ejector latches  30 A,  30 B pivot along the plane  40 . 
     The top view of  FIG. 5A  emphasizes that a distal portion of the upper arm  31 A of the first ejector  30 A lies only on a first side  42  of the plane  40  and a distal portion of the upper arm  31 B of the second ejector  30 B lies only on a second side  43  of the plane  40 . Accordingly, when either of the ejectors is pivoted to an open position, the distal portions of the upper arms will not engage, but are allowed to interleave. 
     Preferably, the first bumper  33 A lies only on the second side  43  of the plane  40  and the second bumper  33 B lies only on the first side  42  of the plane  40 . Accordingly, when either of the ejectors is pivoted to an open position, the bumpers will not engage each other, but are also allowed to interleave. 
       FIG. 5B  is a top view similar to  FIG. 5A , but showing the first ejector latch  30 A in the open position, while the second ejector latch  30 B remains in the closed position.  FIG. 5B  is consistent with  FIG. 4A , when the first ejector latch  30 A is in the open position (dashed lines in  FIG. 4A ). Note that the first and second ejector latches  30 A,  30 B have stayed on their original side of the plane  40  and are now interleaved. 
       FIGS. 6A-D  are a series of side views of the first and second ejector latches  30 A,  30 B showing how the bumpers  33 A,  33 B are used to close one ejector latch as another ejector latch is opened. As shown in  FIGS. 6A-D , the first memory module connector  20 A is empty (i.e., it does not have a memory module installed therein) and the first ejector latch  30 A is in the open position. Presumably, this situation has come about after the first ejector latch  30 A has been used to assist removal of a memory module. The distal portions of the first and second ejector latches  30 A,  30 B are interleaved and the upper arm  31 A of the first ejector latch  30 A is in contact with the bumper  33 B of the second ejector latch  30 B. 
     In reference to  FIG. 6A , the embodiment shown makes it unnecessary to first manually close the first ejector latch  30 A and then, in a separate step or motion, to manually move the second ejector latch  30 B to its open position to unlatch and assist in removal of the second memory module  24 B. Rather, a user may use the finger grip  32 B to move the second ejector latch  30 B to the open position and, in doing so, the second ejector latch  30 B will push the first ejector latch  30 A closed with the same motion. 
     In  FIG. 6B , as the second ejector latch  30 B is pivoted in a direction away from the second memory module  24 B, the bumper  33 B (see the dashed portion behind the interleaved bumper  33 A) pushes against the side of the upper arm  31 A of the first ejector latch  30 A. During this movement, the bumper  33 B will slide downward along the side surface of the ejector latch  30 A. 
     In  FIG. 6C , the second ejector latch  30 B continues to be manually pivoted in a direction away from the second memory module  24 B, until (as shown) the bumper  33 A on the first ejector latch  30 A makes contact with the side of the upper arm  31 B of the second ejector latch  30 B and the bumper  33 B on the second ejector latch  30 B is no longer in contact with the side of the upper arm  31 A of the first ejector latch  30 A. Still further pivoting of the second ejector latch  30 B to the open position (See  FIG. 6D ) causes the bumper  33 A to slide up the side surface of the upper arm  31 B of the second ejector latch  30 B. 
       FIG. 6D  shows that the second ejector latch  30 B is now in the open position and the first ejector latch  30 A is now in the closed position. Although not shown, the pivoting of the second ejector latch  30 B has caused a lower arm (the same as lower arm  36 A of the first ejector latch  30 A in  FIG. 3A ) to lift and unseat the second memory module  24 B. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components and/or groups, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention. 
     The corresponding structures, materials, acts, and equivalents of all means or steps plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but it is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.