Abstract:
A lever and latching arrangement having a pair of camming surfaces disposed on one end thereof is attached to one end of a tailstock member of an electronic memory book or central electronic complex book of a computer. This lever arrangement, as rotated about a pivot axis, engages one of the camming surfaces with a portion of the computer frame; the mechanical advantage of the lever system overcomes the large forces required to connect or disconnect the electronic book from the computer connectors. The pivot axis is positioned between the side rail of the book and the computer frame and between the tailstock and the connectors of the book to afford a low profile relative to the tailstock, permitting a more efficient use of available volumetric space within the computer. On the end of the lever distal from the pivot axis, the lever supports a latch which is insertable into a latch-retaining opening in the tailstock of the book, providing the capability to latch the lever in the installed position while not requiring any additional height of the lever structure.

Description:
FIELD OF THE INVENTION 
     This invention relates to mechanisms for assisting in the electrical connection of memory, central electronic complex, and other similar electronic books to the electrical connector of a computer and, more specifically, to this high leverage insertion lever and latching system necessary on an electronic book frame and connector in order to exert the large forces required to properly connect books with computer connectors. 
     BACKGROUND OF THE INVENTION 
     Computers and servers now are designed with very large internal memories requiring very large numbers of memory modules. Each memory module or memory chip requires a plurality of connections, both to and through the circuit board onto which it is mounted and to the circuit board connectors, which then may be connected to mating connectors as part of the host computer. Similarly, a large and complex central electronic portion of the computer is required to control, address and efficiently utilize the large internal memories. The interconnection of the circuit board connectors on the memory panels and central electronic complex panels to the computer connectors effectively connects the memory or other electronic modules to the circuitry of the host computer. 
     In order to make a computer easily maintainable and repairable, as necessary, the memory modules and the components of the central electronic system are mounted on a plurality of removable and replaceable electronic circuit boards. These electronic circuit boards are mounted within rigid frames which permit the circuit boards and associated circuit board connectors to be removed from the computer and changed out with a replacement assembly providing protection from the high level forces necessary for insertion and removal. The completed assembly of the memory modules, circuit board, frame and connectors are commonly collectively referred to as a “book.” Additionally a central electronic complex for the computer may be made into a “book” for the same reasons. 
     Each book must be easily removable and replaceable with respect to the computer framework or connections to the electronics of the computer. Removal and re-connection of books during operation of the computer or server is referred to as “hot plugging.” As it is common for computers to be operational at all times, maintenance and repair must be accomplished to whatever extent possible while the computer is operating, thus requiring hot plugging. Thus, the installation and removal of the book must be accomplished to insure minimal, if any, disruption to the continued computer operation. 
     With a large memory capacity or a large number of electronic components necessary for a central electronic complex assembled as a book, the number of connections required between the book and computer circuits can and does become quite large. For example, a typical connector may have 1112 pin-in-socket interfaces. More or fewer such connections may be incorporated as dictated by the type and the number of chips or electronic components on the electronic circuit board of the book. 
     A typical book of memory or central electronic complex book may require connection forces of up to 190 pounds or disconnection forces of 60 pounds or more, force levels which generally are not manageable by service or assembly personnel without an additional apparatus to assist and evenly apply the connection or disconnection forces to the book frame. This connection or disconnection force is the cumulative force made up of the combined frictional resistance forces of connection or disconnection for each individual pin and socket connection. Even and proper distribution of the connection and disconnection forces to the book frame is necessary to prevent any potential bending or damaging of the pins and/or misconnection of any connector on the electronic circuit board of the book. 
     A prior art lever and latching system which has been used to aid in the insertion, connection, disconnection and removal of a electronic book in a computer is illustrated in FIG.  1 . The lever and latching system in FIG. 1 is such that the maximum utilization of the space within the computer, by maximization of the dimensions of the circuit board within a particular book, has been compromised both by the volume of space required for the latching and retention apparatus as well as the resulting unusable space between the latches. The disposition of the latches on the exposed, external planar surface  12  of the tailstock  10  by the positioning of bracket  14  and pivot  18 , as illustrated, consumes excessive space. Additionally, the disposition of latch  22  to engage the latching surface  32  of bracket  14  further requires the latch arms  16  to be displaced significantly from tailstock  10  in order to accommodate the latch structure and permit manual access to the release member  28 . With the consumption of available space by the latch arm  16 , the remaining space is unduly limited within the computer frame for the book including the electronic circuit board and the electronic modules. 
     OBJECTS OF THE INVENTION 
     It is an object of the invention to ease the insertion and connection of electronic books into a computer frame. 
     It is another object of the invention to easily overcome the large cumulative frictional forces encountered whenever connecting or disconnecting large numbers of pin-in-socket connectors in a computer. 
     It is a further object of the invention to latch and retain an electronic book within a computer whenever connected to the computer. 
     It is still another object of the intention to reduce the required space for the electronic book installed within the host computer. 
     SUMMARY OF THE INVENTION 
     An electronic book, such as a memory book or a central electronic complex book and which is intended for insertion into and incorporation into a computer as a subassembly, is provided with a pair of levers which engage the frame of the computer at ends closely spaced to the fulcrums of the levers, thereby resulting in a significant mechanical advantage. The levers and their mechanical advantage are employable to connect or disconnect the electrical connectors of the electronic book with and from connectors of the computer both with much lower manual forces and evenly applied connection forces. 
     The levers or latch arms are pivoted about axes which are disposed intermediate the extended plane of the book tailstock to which the levers are mounted and the extended plane of the connector housing interface surface on the electronic circuit board of the book. On ends distal from the pivot axes, the levers carry latches which engage the tailstock to hold the levers in a desired latched position, thus insuring retention of the book in a desired position relative to the computer&#39;s connectors. The latches are extensions affording a low profile to the latch arm or levers. The latch arms are further formed to provide an end surface which, once latched, reside on the outer surface of a flange of the computer frame giving mechanical advantage to the force and movement required for disconnection of and removal of the book from the computer connector. With forces of up to  190  pounds required to connect an electronic book to the computer connector, the mechanical advantage required must be large while the displacement provided by a latch arm movement must be adequate to fully engage the connectors. 
     The design of the latch arm and latch on the distal end of the latch arm and its incorporation into the book assembly affords a low profile which permits the design of a computer with either a larger electronic book with an increased electronic module carrying capacity to be used within a given frame size or a smaller frame to accept a predetermined sized electronic book. 
     While sufficiently rigid to transmit the connection/disconnection forces to the electronic book, the latch arms also must be resilient to the degree permitting a final deflection to latch once the electronic book is fully plugged and to maintain a loading on the connectors. 
     A better and more complete understanding of the invention may be derived from the attached drawings and the detailed description of the invention to follow. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS. 
     FIG. 1 shows an exploded view of a prior art latching system for inserting and latching books within a computer, which not only consumes excessive space but limits efficient space utilization as well. 
     FIG. 2 illustrates a portion of an electronic book, book guide, and book frame incorporating the latching and retention system of the present invention. 
     FIGS. 3 and 4 illustrate partially-exploded views of the latching system of the present invention as attached to tailstocks of different type books. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     OF THE BEST MODE FOR IMPLEMENTING THE INVENTION AS CONTEMPLATED BY THE INVENTORS 
     FIG. 1 illustrates the prior art wherein the tailstock  10  of an electronic book, such as a memory book or a central electronic complex book, is illustrated in a vertical orientation The remainder of the book frame, a circuit board, and electronic connectors are not shown in FIG.  1 . Tailstock  10  is a book frame member having a generally exposed planar surface  12  which supports latch pivot brackets  14 . The latch pivot brackets  14  are attached to the tailstock  10  on the exposed planar surface  12  by screws, rivets, welding or other conventional attaching techniques (not shown). 
     The latch pivot brackets  14 , each disposed proximate opposite ends of the tailstock  10 , each support a latch arm  16 . The latch arm  16  is pivotally supported on a latch pin  18  and is movable around the pivot pin  18  to engage the camming lip  20  of latch arm  16  with a computer frame member (not shown in FIG. 1 but the same as or similar to flange  82  of FIG.  2 ). 
     Again referring to FIG. 1, the latch arm  16  further is provided with a latch member  22  supported on a slightly deflectable or flexible member  24  extending from the back or underside  26  of latch arm  16 . The latch  22  is manipulated by a finger pulling latch release  28  toward latch arm  16  thereby deflecting latch  22  from its normal at-rest position or from its position biased against a latching or engaging surface  32  formed into the end of the latch pivot bracket  14 . This pulling action on latch release  28  releases latch  22  from the latching surface  32  of pivot bracket  14 , thereby releasing latch arm  16  for pivotal movement about pivot pin  18 . 
     In the exploded presentation of FIG. 1, the tailstock assembly  8  is shown in a vertical orientation but may be positioned in a horizontal orientation permitting a drop-in installation of the book rather than slide-in installation, if preferred. A drop-in installation may be preferable to minimize the need for substantial guide and support structures in the computer frame. The weight of the electronic book, typically four to eight pounds, does not need to be supported or held in a cantilevered fashion during alignment and installation in a drop-in orientation with the tailstock  10  horizontally oriented. 
     Referring now to FIGS. 2,  3  and  4  and initially to FIG. 2, an electronic book  50  incorporating the present invention is illustrated with portions broken away to permit observation of some parts otherwise hidden from view. Electronic book  50  is shown with an electronic circuit board  52  attached to frame  54  of electronic book  50  by screws  56  or other conventional fasteners. Circuit board  52  may be a memory circuit board, a central electronic complex circuit board or any other suitable type circuit board. The book frame  54  includes a rigid metal plate or card stiffener plate  120  in FIG. 4, which extends across the width and height of the electronic book  50 , with the edges of the plate  120  formed to make up or be attached to the electronic book frame  54 . Electronic book frame  54  is so constructed to result in a very rigid structure that supports circuit board  52  and the ganged electrical connectors  58  attached and supported on one edge  66  of the electronic circuit board  52  opposite tailstock  60 . 
     In an electronic book  50 , which includes a large number of the memory modules  62 , memory modules  62  are connected by connectors  64  or sockets  64  to the circuit board  52 . Depending upon the size and capacity of the memory modules  62 , (one of which is illustrated in FIGS.  2  and  4 ), a typical book may include from thirty-two large memory modules  62  up to a much larger number of smaller capacity modules. In either instance, connectors  58 ,  118  which conduct signals for addressing and accessing the memory modules  62  of electronic book  50  are positioned and connected along one edge  66  of electronic circuit board  52  in the form of connectors  58 . 
     Connectors  58  extend substantially along the entire length of edge  66  of circuit board  52 . Connectors  58  may incorporate more than 1,000 individual socket connections for mating with a like number of connector pins  90  which are part of the computer  114  circuitry. 
     Connectors  118  and pins  90  are disposed on a frame portion  116  of computer  114 . The frame portion  116  of computer  114  also supports a plurality of alignment guide pins  124  which align with and enter guide pin sockets  122 , ensuring that the electrical connector pins  90  are aligned with their respective connector sockets  64  in connectors  58 . 
     Attached to the exterior planar surface  70  of tailstock  60  and extended outwardly from ends  76  are pivot brackets  72 . The pivot brackets  72  are attached proximate the ends  76  of the tailstock  60  to engage computer frame flange  82  and latch arm  78  to provide balanced forces for connection and disconnection of the electronic book  50 . In FIGS. 2,  3 , and  4 , only one lever and latching assembly is illustrated; however, one such assembly is incorporated on each of two adjacent comers of an electronic book  50 . 
     The attachment of pivot brackets  72  to tailstock  60  may be by any conventional means such as screws, rivets or welding (not shown). The attachment of pivot bracket  72  must sufficiently resist large forces that attempt to separate the pivot bracket  72  from tailstock  60  whenever electronic book  50  is being installed and connected. A pivot pin  74  is supported by the pivot bracket  72  and disposed so that the axis of pivot pin  74  is substantially orthogonal to the plane of electronic circuit board  52 . Pivot pin  74  is further located proximate the side edges  68  of book frame  54  such that the pivot axis of pivot pin  74  is not located farther from edge  66  of circuit board  52  than the tailstock  60 . This location is important to render the latch arm system a low profile system and conserve space within computer  114 . With the space conserved, it may be used to expand the Size of the electronic circuit board  52 , permitting further expansion of the capabilities of the electrical circuit board  52   
     The end  80  of latch arm  78  is pivoted about pivot pin  74  and engages computer frame flanges  82  and, as rotated, causes the forcing of pivot  74  farther into the frame of the receiving computer. As pivot pin  74  is forced farther toward the frame portion  116  of the computer  114 , the connectors  58  are forced onto the mating connector pins  90  to the maximum extent possible, completing the electrical connections between electronic book  50  and the computer connector  118 . 
     The structure of latch arm  78  and the related latch bracket  72  are illustrated in FIGS. 3 and 4. Latch arm  78  is formed with a groove  84  in the material forming the portion of latch arm  78  encircling pivot  74 . Groove  84  is dimensioned and disposed to accept computer frame flange  82 , as illustrated in FIG.  2 . Whenever flange  82  resides in groove  84 , end  80  will be disposed behind flange  82  and, upon rotation of the latch arm  78  toward the tailstock  60 , can engage flange  82 . Surface  85  formed by groove  84  can engage the front of flange  82  once latch arm  78  is rotated away from the tailstock  60 . 
     The fully plugged height of the electronic book  50  or distance between the computer connector  118  and the tailstock  60  of the electronic book  50  may vary from one book  50  to the next due to manufacturing tolerances and the depth to which the pins  90  mate with the sockets  64  in the connectors  58 . Accordingly, the fully plugged lever position requires a degree of flexibility in the latch arm  78  to permit latching whenever the latch arm  78  reaches its limit of rotational travel and to provide a constant preload on the connectors  58 ,  118  as well as a loading of latch surface  96  of latch structure  88  agains latching surface  100 . The “V”-shaped latch structure  88  is supported by distal end  86  of latch arm  78 . Depending leg  87  of latch structure  88  is formed thick enough so as to be substantially rigid with the trough portion  92  thin enough to locally flex. Release leg  94  of latch structure  88  carries a latch surface  96  and is similarly rigid. Trough portion  92  effectively acts as a limited hinge or flexure and provides a restore force to force latch/release leg  94  against the edge of aperture  98  in tailstock  60 . 
     Aperture  98  is disposed to accept the entry of latch structure  88  and further provides a latching surface  100  which engages latch surface  96  of latch structure  88  whenever latch structure  88  is inserted into aperture  98  and forced sufficiently to pass latch surface  96  beyond latching surface  100 . 
     Latch arm  78  is further formed with a circular recess  102  circumscribing fulcrum hole  104  through which pivot pin  74  passes. Circular recess  102  accepts coiled torsion spring  106  surrounding pin  74 . One end  108  of the coiled torsion spring  106  is trapped in recess  112  within latch arm  78 , and the opposite end  110  of coil torsion spring  106  engages latch bracket  72  or alternatively engages tailstock  60  to provide an opening bias to latch arm  78  insuring engagement of latch surface  96  with latching surface  100 . 
     The low profile of the latch arm  78  and the location of the pivot axis of pivot pin  74  permits implementation of a lever actuator and a latching arrangement in a small space; moreover, they permit the implementation of the latch arm  78  on a plurality of different styles or type electronic books  50  or insertable electronic circuit boards  52  and their respective tailstocks  60  and frames  54  or card stiffener plates  120 . 
     In order to install the electronic book  50  or other electronic circuit board  52  with a frame  54  and tailstock  60 , connectors  58  are first inserted into the computer  114 . Particularly in a slide-in installation, the electronic book  50  is too heavy to be conveniently supported and guided by hand with the accuracy required. Guide sockets  122  (as shown in FIG. 4) are engaged with guide pins  124 . The guide sockets  122  precisely align the connectors  58  with a mating connector  118  in the computer  114 . The latch arm  78 , once unlatched, presents surface  85  to flange  82  and end  80  of latch arm  78  passes flange  82 . Upon rotation of latch arm  78  about pivot pin  74 , the end  80  of latch arm  78  rotates with flange  82  in groove  84  until end  80  engages flange  82 . Thereafter, any further rotation of the latch arms  78  toward the tailstock  60  will force pivot pin  74  and latch bracket  72  toward connectors  118  of the computer  114  and seat the electronic circuit board connectors  58  onto the mating connector pins  90 . The latch arms  78  then are latched by pushing latch surface  96  past latching surface  100  on tailstock  60 . 
     To remove the electronic book  50  from connection with the computer  114 , latch release leg  94  is manually displaced toward pivot pin  74 , flexing trough portion  92  and latch surface  96  is disengaged from latching surface  100 . Latch arm  78 , under the influence of the spring  106 , rotates about pivot pin  74  until surface  85  engages flange  82 . Thereafter, the latch arm  78  may be further manually rotated to force its surface  85  against flange  82  and cam the tailstock  60  and the attached electronic circuit board  52  and connectors  5  away from the mating connectors  118 , disconnecting the electronic circuit board  52  from the computer  114 . 
     The large frictional resistance forces generated by several hundred pin-in-socket engagements in the connectors  58 ,  118  are overcome by the mechanical action and the mechanical advantage of the latch arm  78  transmitting the manual force exerted thereon to the pivot pin  74  to install electronic book  50  into or extract electronic book  50  from the computer  114 . 
     Thus, a relatively low level force is required to install or remove a memory or central electronic complex book into or from the computer and this not only insures that fragile elements and connectors are not damaged, but also that a more uniform force is exerted to make or disconnect the several hundred connections without bending or damaging the pins of the computer connector. 
     One of ordinary skill in the art will recognize that various minor modifications may be made to the invention without removing the resulting device from the scope of protection afforded by the attached claims which define the scope for protection of this invention.