Abstract:
A latching device for latching a storage device module into a storage chassis is provided. The latching device includes a latch member having a latching end and a spring end opposite the latching end, the latch member slidingly disposed within a front bezel of the storage device module and being movable between a latching position and a releasing position. The latching device also includes a latch spring between a bearing surface of the front bezel and the spring end of the latch member. The latch spring is in increased compression when the latch member transitions from the latching position to the releasing position, and the latch spring is in decreased compression when the latch member transitions from the releasing position to the latching position. The latching end extends through a latch hole in a side member of the storage chassis for locking the storage device module in the chassis.

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application is related to pending non-Provisional U.S. application Ser. No. 13/______ (Docket No DHP0098 US, filed Jan. 11, 2012, entitled STORAGE DEVICE CARRIER EJECTION SPRING inventors Brenden Michael Rust, Michael David Keffeler, and Andrew Rudolph Heyd). 
     
    
     FIELD 
       [0002]    The present invention is directed to computer data storage. In particular, the present invention is directed to a storage device module latch for retaining storage device modules in storage enclosures. 
       BACKGROUND 
       [0003]    Storage subsystems provide system mass storage incorporating many storage devices. Storage devices usually include hard disk drives, but may include solid-state drives, optical drives, or tape drives. Storage subsystems include within a single storage chassis one or more storage devices, power supplies, and possibly one or more storage controllers, including Redundant Array of inexpensive disks (RAID) controllers. 
         [0004]    In order to provide non-stop operation, redundant controllers, power supplies, and/or storage devices are often provided in the storage subsystem. Additionally, such assemblies are generally provided as field replaceable modules or FRUs. Field replaceable modules are packaged individually, in order to facilitate removal and replacement of individual controllers, power supplies, or storage devices. Additionally, such modules are often hot replaceable, and able to be replaced while the storage subsystem is powered up and even actively conducting I/O operations to one or more storage devices. Individual storage devices are commonly packaged within a storage device module consisting of a sheet metal tray for mounting the storage device and a front bezel incorporating a latching mechanism, and in some cases visual indicators. 
         [0005]    Many storage devices incorporate relatively large and robust midplane connectors, which convey power and I/O signals between the storage device and the midplane. Such connectors often have high pin counts, resulting in high insertion and removal forces. In order to overcome high removal forces, storage device modules incorporate cams, levers, or other mechanically advantaged latch mechanisms. 
       SUMMARY 
       [0006]    The present invention is directed to solving disadvantages of the prior art. In accordance with embodiments of the present invention, a latching device for latching a storage device module into a storage chassis is provided. The storage chassis confines an open-ended receiving space that extends in a first direction and that receives slidably and removably the storage device module therein. The storage chassis has a wall comprising a latch hole that borders the receiving space. The latching device includes a latch member having a latching end portion and a spring end portion opposite the latching end portion. The latch member is slidingly disposed within a front bezel of the storage device module and is movable in a second direction transverse to the first direction between a latching position and a releasing position. The latching end portion of the latch member in the latching position extends through the latch hole for locking the storage device module into the storage chassis. The latching end portion of the latch member in the releasing position is extracted from the latch hole thereby permitting the removal of the storage device module from the receiving space. The latching device also includes a spring member for providing spring force in the second direction and disposed within the front bezel between a bearing surface of the front bezel and the spring end portion of the latch member. The spring member is in increased compression when the latch member transitions from the latching position to the releasing position. The spring member is in decreased compression when the latch member transitions from the releasing position to the latching position. 
         [0007]    In accordance with another embodiment of the present invention, a storage device module for providing independent insertion and removal of a storage device in a storage chassis is provided. The storage device module includes a tray, slidingly engaged in a first direction to one or more storage chassis surfaces forming a receiving space that receives the storage device module therein and a bezel, forming a front surface of the storage device module and fastened to the tray. The bezel includes a latch. The latch includes a latching end portion and a spring end portion, opposite the latching end portion. The latch is finger-movable in a second direction transverse to the first direction between a latching position and a releasing position. In the latching position, the latching end portion of the latch extends through a latch hole in one of the one or more storage chassis surfaces for locking the storage device module into the storage chassis. In the releasing position, the latching end portion of the latch is not engaged with the latch hole. The latch in the releasing position unlocks the storage device module from the storage chassis and permits the removal of the storage device module from the receiving space. The latch also includes a latch spring for providing force in the second direction and disposed within the bezel between a bearing surface of the bezel and the spring end portion of the latch member. The latch spring is in an increased compression state when the latch member transitions from the latching position to the releasing position. The latch spring is in a decreased compression state when the latch member transitions from the releasing position to the latching position. 
         [0008]    In accordance with another embodiment of the present invention, a method for inserting a storage device module into a receiving space of a storage chassis is provided. The method includes positioning the storage device module in alignment with the receiving space such that a faceplate assembly of the storage device module is oriented on a side of the storage device module opposite the receiving space and a top surface of the storage device module faces the top of the receiving space, moving the storage device module into the receiving space until a latching end portion of a latch member in the faceplate assembly makes contact with a side surface of the storage chassis, the latch member comprising the latching end portion and a spring end portion opposite the latching end portion, and pushing the storage device module fully into the receiving space. The latching end portion engages a latch hole in a side interior surface of the storage chassis bordering the receiving space of the storage chassis when the storage device module is fully pushed into the receiving space. 
         [0009]    In accordance with yet another embodiment of the present invention, a method for removing a storage device module from a receiving space of a storage chassis is provided. The method includes sliding a latch member in a second direction, the latch member including a latching end portion and a spring end portion opposite the latching end portion. The latching end portion engages a latch hole in a storage chassis interior surface bordering the receiving space prior to sliding the latch member, and disengages the latch hole while sliding the latch member. A latch spring in contact with the spring end portion provides a force opposite to the second direction. The method also includes pushing the storage device module out of the receiving space by an ejection spring providing force in a first direction between the storage chassis and the storage device module and orthogonal to the second direction. The ejection spring pushes the storage device module a first predetermined distance in the first direction after the latching end portion disengages the latch hole. The method further includes grabbing the storage device module by a bezel finger recess of a faceplate assembly, and pulling the storage device module from the receiving space of the storage chassis. The faceplate assembly forms a front surface of the storage device module. 
         [0010]    An advantage of the present invention is it allows a simpler and less costly storage device module latch to be used for storage device module ejection, compared to conventional approaches. Conventional storage device latches require mechanical advantage to overcome midplane or backplane connector insertion and removal forces. In order to provide the required mechanical advantage, conventional storage device latches include levers or rotating cams that bear against a storage chassis surface bordering the storage device module. 
         [0011]    Another advantage of the present invention is it restricts all storage device module latch movement within the envelope of the bezel of the storage device module. Less physical space in front of the storage device module and storage chassis is required since no cam levers or other mechanical structures are required in order to insert or remove a storage device module from a storage chassis. 
         [0012]    Additional features and advantages of embodiments of the present invention will become more readily apparent from the following description, particularly when taken together with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a block diagram illustrating representative components of a storage system in accordance with embodiments of the present invention. 
           [0014]      FIG. 2  is a diagram illustrating a storage chassis comprising a storage subsystem in accordance with embodiments of the present invention. 
           [0015]      FIG. 3  is a diagram illustrating a storage device module and selected internal features of a storage chassis in accordance with embodiments of the present invention. 
           [0016]      FIG. 4  is a diagram illustrating assembly of drive ejection springs into a first chassis support member in accordance with the present invention. 
           [0017]      FIG. 5  is a diagram illustrating assembly of first and second chassis support members in accordance with the present invention. 
           [0018]      FIG. 6   a  is a diagram illustrating a drive ejection spring isometric view in accordance with the present invention. 
           [0019]      FIG. 6   b  is a diagram illustrating a drive ejection spring top view in accordance with the present invention. 
           [0020]      FIG. 6   c  is a diagram illustrating a drive ejection spring side view, section A-A, in accordance with the present invention. 
           [0021]      FIG. 6   d  is a diagram illustrating a drive ejection spring end view, section B-B, in accordance with the present invention. 
           [0022]      FIG. 7  is a diagram illustrating self-latching storage device module components, in accordance with the preferred embodiment of the present invention. 
           [0023]      FIG. 8   a  is a diagram illustrating a bezel rear view with a latch member in a latching position, in accordance with the preferred embodiment of the present invention. 
           [0024]      FIG. 8   b  is a diagram illustrating a bezel rear view with a latch member in a releasing position, in accordance with the preferred embodiment of the present invention. 
           [0025]      FIG. 9   a  is a diagram illustrating a bezel left rear view with a latch member in a latching position, in accordance with the preferred embodiment of the present invention. 
           [0026]      FIG. 9   b  is a diagram illustrating a bezel left rear view with a latch member in a releasing position, in accordance with the preferred embodiment of the present invention. 
           [0027]      FIG. 10   a  is a diagram illustrating a bezel right rear view with a latch member in a latching position, in accordance with the preferred embodiment of the present invention. 
           [0028]      FIG. 10   b  is a diagram illustrating a bezel right rear view with a latch member in a releasing position, in accordance with the preferred embodiment of the present invention. 
           [0029]      FIG. 11  is a diagram illustrating an assembled self-latching storage device module, in accordance with the preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    The present invention is directed to the problem of eliminating bulky storage device ejection components in storage subsystems where low-insertion force storage device midplane connectors are being used. 
         [0031]    Referring now to  FIG. 1 , a block diagram illustrating representative components of a storage system  100  in accordance with embodiments of the present invention is shown. Storage subsystem  100  includes storage chassis  104 . Storage system  100  may include multiple storage chassis  104 , or a single storage chassis  104 . Storage chassis  104  is generally, but not necessarily, a sheet metal cabinet enclosing multiple assemblies. In some embodiments, the assemblies are individually packaged in sheet metal or plastic enclosures, and are designed with hot pluggable and/or redundant operation in mind. 
         [0032]    Storage chassis  104  includes one or more storage devices  120 , shown in  FIG. 1  as storage device  120   a  through  120   n . Storage devices  120  include hard disk drives, solid state drives, optical drives, and tape drives. Each storage device  120  is packaged in a storage device module that allows one or more storage devices  120  to be removed or replaced within storage chassis  104 . 
         [0033]    Storage chassis  104  includes a midplane  116 , which provides interconnectivity between the various modules within storage chassis  104 . Midplane  116  is the only assembly fixed within storage chassis  104 , and is therefore often only designed with passive circuitry to increase reliability and reduce the need for replacement. Midplane  116  provides power and signal interconnectivity between storage controllers  108 , power supplies  112 , and storage devices  120 . 
         [0034]    Storage chassis  104  includes one or more power supplies  112 , shown as power supply  112   a  and power supply  112   b . Power supplies  112  are designed such that any one power supply  112  may power all assemblies included in storage chassis  104 , even if another power supply  112  has failed. 
         [0035]    Storage chassis  104  may optionally include one or more storage controllers  108 , shown as storage controller  108   a  and storage controller  108   b . Storage controllers  108  are usually implemented as redundant storage controllers  108 , allowing any one storage controller  108  to control all storage devices  120  even if another storage controller  108  has failed. Storage controllers  108  often include redundant array of inexpensive desk (RAID) technology to provide additional redundancy and performance when accessing groups of storage devices  120 . In some embodiments, storage chassis  104  includes no storage controllers  108   a , such as in a JBOD storage chassis  104 . JBOD storage chassis  104  are usually expansion storage chassis  104 , in order to provide a greater number of storage devices  120  in storage system  100 . 
         [0036]    Referring now to  FIG. 2 , a diagram illustrating a storage chassis  104  comprising a storage subsystem in accordance with embodiments of the present invention is shown. 
         [0037]    In order to obtain a high degree of packaging efficiency when including multiple storage chassis  104  in storage system  100 , storage chassis  104  is often designed as a rack-mountable storage enclosure. Multiple rack-mountable storage enclosures are able to be mounted in a single 19 inch rack. Storage chassis  104  is therefore often designed in increments of rack units to allow efficient stacking within a 19 inch rack. In one embodiment, storage chassis  104  is two rack units high. In other embodiments, storage chassis  104  is less or more than two rack units high. 
         [0038]    Storage chassis  104  includes multiple storage device modules  208 . In one embodiment, storage chassis  104  includes 12 storage device modules  208 . In other embodiments, storage chassis  104  includes less than or more than 12 storage device modules  208 . In one embodiment each storage device module  208  includes one storage device  120 . In another embodiment, each storage device module  208  includes two or more storage devices  120 . In some embodiments, storage device modules  208  do not include any storage devices  120 . Such would be the case in a partially populated storage chassis  104  that included the ability to expand storage capacity by adding additional storage devices  120  in the future. 
         [0039]    Although storage chassis  104  includes one or more power supplies  112  and possibly one or more storage controllers  108 , these assemblies are not specifically shown in  FIG. 2  but should be generally understood to be present. 
         [0040]    Referring now to  FIG. 3 , a diagram illustrating a storage device module  208  and selected internal features of a storage chassis  104  in accordance with embodiments of the present invention is shown. 
         [0041]    Storage device modules  208  are designed to allow user insertion and/or removal of any storage device module  208  into an open-ended receiving space of a storage chassis  104 . Storage device modules  208  are removed from the storage chassis  104  in a first direction, which is the same as direction  316  of  FIG. 3 . 
         [0042]    Storage device module  208  removal is required in order to service any storage devices  120  in storage device module  208 , or to add a storage device  120  to storage device module  208 . In many embodiments, storage device module  208  is designed to be hot-pluggable within storage chassis  104 . Hot-plugging allows storage device module  208  to be inserted or removed from storage chassis  104  with power on. 
         [0043]    Chassis support members  304  are provided in storage chassis  104  to compartmentalize storage chassis  104  in order to support multiple storage device modules  208 . Chassis support members  304  also provide support for top and bottom surfaces of storage chassis  104 , thereby improving storage chassis  104  structural integrity. 
         [0044]    In order to make storage device modules  208  hot-pluggable, rail systems are built into storage chassis  104 . Rail surfaces  312  are provided on chassis sidewalls  308  and chassis support members  304  allow storage device modules  208  to slide within storage chassis  104 . 
         [0045]    Generations of storage devices  120  have required relatively high insertion forces. Part of the reason for this are high connector pin counts on storage devices  120  required to support many power, ground, and parallel bus signal interconnections. In many cases, storage devices  120  included separate power and signal I/O connectors—which contribute to higher storage device  120  insertion and removal forces. For example, the 4-contact Molex-style power connector used with IDE and parallel SCSI storage devices  120  requires up to 6 lbs for removal force and 16 lbs for insertion. VHDCI connectors used for parallel SCSI storage devices  120  require 8.25 lb for insertion and 2.29 lb for removal. SCA-2 connectors require 7.9 lb for insertion and 1.32 lb for removal. 
         [0046]    As storage devices  120  evolved, manufacturers have similarly evolved midplane storage device  120  connectors. Lower power circuitry on storage devices  120  means that fewer power and ground I/O connections are required, and smaller and more efficient connector contacts may be used. Also, storage devices  120  have reduced pin counts due to more efficient serial signal I/O, such as that provided in Fiberchannel, SATA, and SAS technologies. As a result, midplane  116  or backplane connectors are smaller, lighter, and require significantly lower insertion and removal forces than previous generation storage devices  120 . For example, SAS 2.0 connectors for storage devices  120  require 4.5 lbs insertion force and 0.56 lbs removal force. 
         [0047]    Referring now to  FIG. 4 , a diagram illustrating assembly of drive ejection springs  404  into a first chassis support member  408  in accordance with the preferred embodiment of the present invention is shown. The drive ejection spring  404  of the present invention exerts a force between 4 and 6 pounds against the storage device module  208  when the storage device module  208  is fully inserted in the storage chassis  104 . Drive ejection springs  404  exert force against the storage device module  208  out the front of the storage chassis  104 , or as illustrated in  FIG. 3  as ejection spring force direction  316 . 
         [0048]    In one embodiment, each chassis support member  304  includes a first chassis support member  408 , and three drive ejection springs  404 . One drive ejection spring  404  is provided for each storage device module  208 . In alternative embodiments, multiple drive ejection springs  404  may be provided for each storage device module  208 . In one embodiment, multiple drive ejection springs  404  are provided for each storage device module  208  in the same first chassis support member  408 . In another embodiment, multiple drive ejection springs  404  are provided for each storage device module  208  in different first chassis support members  408 . 
         [0049]    Drive ejection springs  404  are described in more detail in  FIGS. 6   a - 6   d . In one embodiment, a tab  424  is bent within first chassis support member  408  in order to create a fixed attachment point for a drive ejection spring fully captured end  412 . In other embodiments, the drive ejection spring fully captured and  412  is secured to the first chassis support member  408  with any suitable attachment component, including but not limited to, a screw, a bolt, a rivet, or a weld. 
         [0050]    In one embodiment, a linear slot  420  is provided within first chassis support member  408  in order to provide a means of partially capturing a free end of drive ejection spring  404 . A drive ejection spring partially captured end  416  passes through linear slot  420  to engage a rear surface of storage device module  208 . Linear slot  420  is oriented in order to allow linear movement of the drive ejection spring partially captured end  416  in concert with an inserted storage device module  208 , and prevent linear movement of the drive ejection spring partially captured end  416  in an up or down direction with reference to storage chassis  104 . 
         [0051]    Referring now to  FIG. 5 , a diagram illustrating assembly of first  408  and second  504  chassis support members in accordance with an embodiment of the present invention is shown. Chassis support members  304  are an assembly including first chassis support member  408 , second chassis support member  504 , and drive ejection springs  404 . In one embodiment, there are three drive ejection springs  404  in each chassis support member  304 , located between first chassis support member  408  and second chassis support member  504 . By locating drive ejection springs  404  between first chassis support member  408  and second chassis support member  504 , drive ejection springs  404  are protected from damage. In other embodiments, there may be less than or more than three drive ejection springs  404 . 
         [0052]    Drive ejection springs  404  in one embodiment are held captive between first chassis support member  408  and second chassis support member  504 . Rail surfaces  312  are provided on both the first chassis support member  408  and the second chassis support member  504  to support storage device modules  208  on each side of a chassis support member  304 . 
         [0053]    When a storage device module  208  is inserted into storage chassis  104 , storage device module  208  engages rail surfaces  312  on either side of storage device module  208 . As the storage device module  208  is pushed further into storage chassis  104 , before the storage device module  208  is fully seated, storage device module  208  engages and pushes against drive ejection spring partially captured end  416 . Pushing storage device module  208  further into storage chassis  104  causes drive ejection spring  404  to linearly expand and exert force against the rear surface of storage device module  208 . Pushing storage device module  208  fully into storage chassis  104  causes an electrical connector on the storage device  120  in storage device module  208  to engage a mating connector on midplane  116  of storage chassis  104 , and a latch tab  728  in storage device module  208  to engage a mating latch hole  428  in either chassis support member  304  or chassis sidewall  308 . The drive ejection spring  404  remains in an expanded state, exerting force against the rear of storage device module  208 , until such time as the latch member  712  in storage device module  208  is released. Once the latch member  712  in storage device module  208  is released, stored spring force in expanded drive ejection spring  404  moves storage device module  208  out the front of storage chassis  104  a second predetermined distance where the storage device module  208  comes to rest. In a preferred embodiment, the second predetermined distance is 9.5 mm. In other embodiments, the second predetermined distance may be less than or greater than 9.5 mm. However, the predetermined distance is at least 5 mm. 
         [0054]    Referring now to  FIG. 6   a , a diagram illustrating a drive ejection spring  404  isometric view in accordance with an embodiment of the present invention is shown. 
         [0055]    Drive ejection spring  404  includes three parts: a drive ejection spring body  604 , a drive ejection spring fully captured end  412 , and a drive ejection spring partially captured and  416 . In one embodiment, all three portions of drive ejection spring  404  are formed from a single length of suitable material. In the preferred embodiment, drive ejection spring  404  is formed from 0.796 mm+/−0.010 mm SWIC-F precoated post-plated Nickel ASTM A228 steel music wire, and is stress-relieved after forming. The drive ejection spring  404  has yield strength after stress relieving of 2,400 MPa, or 350,000 PSI, minimum. In other embodiments, drive ejection spring  404  may be formed from Beryllium copper, phosphor bronze, or Titanium. 
         [0056]    In the preferred embodiment of the present invention, the drive ejection spring fully captured end  412  is formed into a loop, where the loop is in the same plane as the drive ejection spring body  604 . In other embodiments, the drive ejection spring fully captured end  412  may be formed into other suitable shapes to facilitate fastening to the first chassis support member  408 . 
         [0057]    Referring now to  FIG. 6   b , a diagram illustrating a drive ejection spring  404  top view in accordance with an embodiment of the present invention is shown. 
         [0058]    In the preferred embodiment, various dimensions of drive ejection spring  404  are illustrated. The body bend length  608  is typically 8.0 mm, the fully captured end bend radius  616  is 3.5 mm, and the body bend radius  612  is 1.1 mm for each of 24 serpentine bends. 
         [0059]    Referring now to  FIG. 6   c , a diagram illustrating a drive ejection spring  404  side view, section A-A, in accordance with an embodiment of the present invention is shown. 
         [0060]    In the preferred embodiment, various dimensions of drive ejection spring  404  are illustrated. The flat length  620  (free length) is 103.44 mm+/−4.0 mm from the center of the loop in the fully captured end  412  to the start of the bend in the partially captured end  416 . The partially captured end height  624  is 3.3 mm, and the partially captured end bend radius  628  is 80 degrees. Once the complete storage chassis  104  is assembled, the drive ejection spring  404  stretches to a maximum length of 109.5 mm, with 6.1 mm of preload extension, when a storage device module  208  is not inserted into the storage chassis  104 . When a storage device module  208  is fully inserted into the storage chassis  104 , the drive ejection spring  404  stretches to a length of 118.9 mm. 
         [0061]    Referring now to  FIG. 6   d , a diagram illustrating a drive ejection spring  404  end view, section B-B, in accordance with an embodiment of the present invention is shown. In the preferred embodiment, the spring width  632  is 10.8 mm. Referring now to  FIG. 7 , a diagram illustrating self-latching storage device module components, in accordance with the preferred embodiment of the present invention is shown. The self-latching storage device module  208  includes several components that allow a storage device  120  to be securely mounted in the self-latching storage device module  208 . 
         [0062]    The self-latching storage device module  208  includes a storage device tray  704 , or tray  704 . Storage devices  120  mount to the storage device tray  704  with various fasteners. In the preferred embodiment, the storage device tray  704  includes four screw holes  728  for attaching a storage device  120  to the storage device tray  704  through side surfaces of the storage device  120 . When mounted in the storage device tray  704 , the storage device power and signal connectors face the rear of the self-latching storage device module  208 , opposite the storage device tray front surface  732 . 
         [0063]    The self-latching storage device module  208  also includes a front bezel  708 , which securely attaches to the storage device tray front surface  732 . The front bezel  708  provides a faceplate for the self-latching storage device module  208 , and includes a finger-activated latch member  712 . The latch member  712  slides horizontally in a second direction within the front bezel  708 , and is captured within the front bezel  708 . The second direction is either the direction of spring latch force  1104  illustrated in  FIG. 11 , when latching the storage device module  208 , or opposite of direction  1104  when releasing the storage device module  208 . 
         [0064]    The latch member  712  includes a latch tab  728 , which engages a latch hole  428  in a chassis support member  304  to lock the self-latching storage device module  208  into the storage chassis  104 . The latch member  712  also includes a latch finger detent  724 . 
         [0065]    The front bezel  708  also includes a latch spring  716 . When unmounted in the front bezel  708 , the latch spring  716  is in an uncompressed state. In a preferred embodiment, the latch spring  716  is formed from a single piece of 0.40 millimeter (mm) spring steel, 301 series stainless steel, or equivalent, ¾ hardness material or equivalent, and exerts a force of between 0.5 lbs and 0.75 lbs, preferably 0.60 lbs, against the latch member  712  in the latching position and between 0.6 lbs and 1.0 lbs, preferably 0.83 lbs, against the latch member  712  in the releasing position. The latch finger detent  724  provides a finger engagement surface by which a user can move the latch member  712  to overcome spring force exerted by latch spring  716  to disengage the latch tab  728  from the latch hole  428 . 
         [0066]    In some embodiments, the self-latching storage device module  208  includes one or more light pipes  720 , which convey light energy from LEDs mounted inside the storage chassis  104  to light pipe windows  736  on the front bezel  708 . 
         [0067]    The self-latching storage device module  208  is installable in storage chassis  104  by only pushing the self-latching storage device module  208  directly into the storage chassis  104 . It is not required to manually actuate the latch member  712  or any other device in either the self-latching storage device module  208  or the storage chassis  104  during such insertion operations. The self-latching storage device module  208  is pushed into the storage chassis  104  a first predetermined distance, at which point a beveled surface of the latch tab  728  makes initial contact with a chassis support member  304 . Therefore, the first predetermined distance is the distance from the rear of midplane  116  connectors of storage device  120  mounted in self-latching storage device module  208  to the rear surface of latch member beveled surface  1004  of latch tab  728 , when the latch member  712  is in the latching position as illustrated in  FIG. 10   a.    
         [0068]    Referring now to  FIG. 8   a  is a diagram illustrating a bezel rear view with a latch member  712  in a latching position, in accordance with the preferred embodiment of the present invention is shown.  FIGS. 8   a ,  8   b ,  9   a ,  9   b ,  10   a , and  10   b  provide various views of an assembled front bezel  708  in order to illustrate the cooperation between the front bezel  708 , the latch member  712 , and the latch spring  716 . 
         [0069]      FIG. 8   a  illustrates an assembled bezel in an at-rest position. The latch member  712  has a latching end portion  812 , and a spring end portion  816 . The latching end portion  812  includes the latch tab  728 , which extends through the side of front bezel  708  when in the latching position in order to engage a latch hole  428 . Opposite the latching end portion  812  of the latch member  712  is the spring end portion  816 . 
         [0070]    The front bezel  708  includes features to capture the latch member  712  in a vertical direction, and only allow side-to-side movement. The front bezel  708  also includes features to limit the side-to-side movement in each direction. 
         [0071]    The latch spring  716  is installed in such a way as to bear against a front bezel bearing surface  820 , and a spring end portion  816  of the latch member  712 . When installed in the front bezel  708  and the latch member  712  in the latching position, the latch spring is in a partially compressed state  808 . That is, the latch spring  716  provides sufficient force against the spring end portion  816  of the latch member  712  to cause the latch tab  728  to protrude from the side of the front bezel  708 . 
         [0072]    Referring now to  FIG. 8   b , a diagram illustrating a bezel rear view with a latch member  712  in a releasing position, in accordance with the preferred embodiment of the present invention is shown.  FIG. 8   b  illustrates an assembled bezel in an actuated position. The actuated position reflects an orientation of the latch member  712  and latch spring  716  when a user exerts force in opposition to the latch spring  716  against the latch finger detent  724 . 
         [0073]    The exerted force causes the latch member  712  to horizontally move toward the center of the front bezel  708 , which disengages the latch tab  728  from the latch hole  428 . As the latch member  712  horizontally moves toward the center of the front bezel  708 , the spring end portion  816  pushes against one end of the latch spring  716 , causing the latch spring  716  to be in a fully compressed state  824 . 
         [0074]    Referring now to  FIG. 9   a , a diagram illustrating a bezel left rear view with a latch member  712  in a latching position, in accordance with the preferred embodiment of the present invention is shown.  FIG. 9   a  shows the same operation illustrated in  FIG. 8   a , but provides an alternative view of the latch spring in the partially compressed state  808 . 
         [0075]    Referring now to  FIG. 9   b , a diagram illustrating a bezel left rear view with a latch member  712  in a releasing position, in accordance with the preferred embodiment of the present invention is shown.  FIG. 9   b  shows the same operation illustrated in  FIG. 8   b , but provides an alternative view of the latch spring in the fully compressed state  824 . 
         [0076]    The front bezel  708  includes a bezel finger recess in the top  904   a  and/or bottom  904   b  surfaces. The bezel finger recess  904   a ,  904   b  is a recessed area that provides user finger purchase in order to extract the self-latching storage device module  208  from the storage chassis  104 . After a user moves the latch member  712  to the releasing position, one or more drive ejection springs  404  exerts force against the storage device tray  704 , and ejects the self-latching storage device module  208  a short distance. In the preferred embodiment, the ejection distance, or second predetermined distance, is approximately 9.5 mm. Once the self-latching storage device module  208  is ejected, a user is able to grab the front bezel  708  by the bezel finger recess  904   a ,  904   b  and pull the self-latching storage device module  208  from the storage chassis  104 . 
         [0077]    Referring now to  FIG. 10   a , a diagram illustrating a bezel right rear view with a latch member  712  in a latching position, in accordance with the preferred embodiment of the present invention is shown.  FIG. 10   a  shows the same operation illustrated in  FIGS. 9   a  and  8   a , but provides an alternative view of the latch spring in the partially compressed state  808 . 
         [0078]    The latch tab  728  includes a latch member beveled surface  1004 . The latch tab  728  is beveled on the rear surface in order to provide simple insertion and locking of the self-latching storage device module  208  in the storage chassis  104 . In the latching position, the latch member beveled surface  1004  protrudes from the front bezel  708 . 
         [0079]    When the self-latching storage device module  208  is pushed within a receiving space of the storage chassis  104 , the latch member beveled surface  1004  will make initial contact with a front surface of a chassis support member  304 . When the self-latching storage device module  208  is pushed further into the storage chassis  104 , the latch member beveled surface  1004  will push against the chassis support member  304 , thereby pushing the latch member  712  toward the center of the front bezel  708  and compressing the latch spring  716 . Once the latch tab  728  is fully registered with the latch hole  428 , the latch spring in the fully compressed state  824  will exert force against the spring end portion  816  of the latch member  712 . This will cause the latch tab  728  to move into the latch hole  428 , thereby locking the self-latching storage device module  208  into the storage chassis  104 . 
         [0080]    Referring now to  FIG. 10   b , a diagram illustrating a bezel right rear view with a latch member in a releasing position, in accordance with the preferred embodiment of the present invention is shown.  FIG. 10   b  shows the same operation illustrated in  FIGS. 9   b  and  8   b , but provides an alternative view of the latch spring in the fully compressed state  824 . In the releasing position, the latch member beveled surface  1004  is retracted within the front bezel  708 . 
         [0081]    Referring now to  FIG. 11 , a diagram illustrating an assembled self-latching storage device module  208 , in accordance with the preferred embodiment of the present invention is shown.  FIG. 11  illustrates the other features from  FIGS. 7-10 , but illustrates the direction of latch spring force  1104  in the preferred embodiment. However, in other embodiments the direction of latch spring force  1104  may be opposite to that shown in  FIG. 11 . 
         [0082]    Finally, those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiments as a basis for designing or modifying other structures for carrying out the same purposes of the present invention without departing from the spirit and scope of the invention as defined by the appended claims.