Abstract:
In an aspect, the invention features a method for inserting a disk drive into peripheral bay chassis. A disk drive is received into a base of a disk drive carrier, the base having an uppermost surface and being rotatably attached to a latching mechanism. A lever can rotate between an open position and a closed position, the lever having comprising a lower engagement point and an upper engagement point. The carrier is inserted into a peripheral bay chassis slot while the lever is in an open position. The carrier is secured to the peripheral bay chassis by rotating the lever to the closed position to extend the upper engagement point beyond the uppermost surface of the base and engage the peripheral bay chassis with and to extend the lower engagement point to engage the peripheral bay chassis.

Description:
This application is a divisional of U.S. Ser. No. 09/264,650, filed Mar. 8, 1999, now U.S. Pat. No. 6,325,353. 

   BACKGROUND OF THE INVENTION 
   This invention relates to disk drive hot swapping. PC networks and, in particular, client server technology have created a need for network servers comprising relatively large and fast processors and random access memory coupled to an expandable array of large, fast hard drives. The hard drives provide non-volatile storage for application programs and data. One efficient method of providing for non-volatile storage is through an array of relatively inexpensive disk drives that can act in concert to provide nonvolatile storage that is faster and more reliable than a single, large, expensive hard disk drive. 
   One technology that enables inexpensive hard drives to cooperate is generally known as a redundant array of inexpensive disks or RAID and is particularly useful in the environment of network servers. RAID provides data redundancy such that if a single disk drive fails, lost data can be reconstructed from data stored on the remaining disks. In addition, multiple hard drives can be mirrored whereby copies of application programs and data are simultaneously stored on multiple disks. In the event of disk failure, a mirror image of a failed drive is available on another disk. 
   A RAID can be monitored and in the event of a disk drive failure, the failed disk can be replaced and data restored without interrupting the operation of a server. In addition, an operational disk drive can be removed and archived at the same or a remote location. An archived disk drive can also be replaced without interrupting the operation of a server. In order to replace a hard drive while the system is operational, a disk drive is “hot swapped,” the term “hot” referring to live voltage and signals being applied to the drive while it is being removed and replaced. 
   Typically, a RAID is housed in a peripheral bay chassis (P-Bay). A P-Bay chassis can efficiently arrange hard drives and supply them with power, control and data connections, while allowing for adequate cooling of hard drives housed within it. A computer can be electrically connected to the P-Bay and thereby be given the advantages of having multiple disk drives. 
   Hard drives have been known to be mounted into a P-Bay chassis by bolting the drive into the chassis, using a cam driven handle to insert the drive into the chassis and other mechanisms. To limit vibrational effects, each hard drive needs to be securely mounted into the chassis. 
   SUMMARY 
   In general the invention features a disk drive carrier and a method for inserting a disk drive into a peripheral bay chassis. In one aspect of the invention the disk drive carrier includes a base for receiving a disk drive and a latching mechanism rotatably attached to the base permitting a lever to rotate between an open position and a closed position. The lever includes a lower engagement point and an upper engagement point. 
   In general, in another aspect, the invention features a base for mounting a disk drive. The base includes a channel formed with an upper surface and a substantially flat interior. The base also includes a lower surface with a substantially flat interior and a side wall with a finned exterior. 
   In general, in another aspect, the invention features an electromagnetic interference (EMI) shield. The EMI shield can include a multi-venthole frontal plate connected at a substantially right angle to a side panel. 
   In general, in another aspect, the invention includes a method for inserting a disk drive into a peripheral bay chassis. The method can include the steps of receiving a disk drive into a base of a disk drive carrier and inserting the carrier into a peripheral bay chassis slot while a lever is in an open position. The lever can then be rotated to the closed position to engage the peripheral bay chassis with the lower engagement point and the upper engagement point. 
   Other features and advantages of the invention will be apparent from the description, drawings and claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an isometric view of an assembled carrier. 
       FIG. 2  is a latching mechanism. 
       FIG. 3  is a profile perspective of a latching mechanism. 
       FIG. 4  is an EMI shield. 
       FIG. 5  is a base. 
       FIG. 6  is a carrier assembly including a hard drive. 
       FIG. 7  is an isometric view of a P-Bay chassis with carriers. 
       FIG. 8  is a frontal view of a P-Bay chassis with carriers. 
   

   DETAILED DESCRIPTION 
     FIG. 1  illustrates a server disk drive carrier assembly  100 . The disk drive carrier assembly includes a latching mechanism  200 , an electromagnetic interference (EMI) shield  400  and a base  500 . 
   The base  500  holds a computer disk drive and serves as a heat sink to dissipate heat generated by the disk drive. The base  500  typically comprises an electrically and thermally conductive material such as aluminum and is formed to provide a channel that matches the size and shape of a hard drive. Referring also to  FIG. 5 , the base can be formed so that the channel has a substantially flat interior upper surface  524 ; a substantially flat interior lower surface  520 ; and a side wall with a finned exterior  510  and a contoured interior surface  522 . Referring also to  FIG. 6 , the contoured interior side surface  522  compliments the exterior contour of a hard drive  625  that can be mounted between the upper surface  524  and lower surface  520 . The finned exterior  510  aids in dissipating heat. To maximize heat transfer from a drive to the base the hard drive may be mounted within the base in contact with interior upper surface  524 , interior lower surface  520  and interior side surface  522 . 
   A computer disk drive  625  can be secured to the base with one or more fasteners such as flat head machine screws  514  inserted through mounting holes  511  formed into the base and set into the drive  625 . Forming a base from an electrically conductive material is useful for grounding a hard drive  625  mounted therein and acting as an electrical path to dissipate electrostatic charges that may build up near the drive  625 . An electrical path from the base  500  to a grounded P-Bay chassis  700  ( FIG. 7 ) can be provided through metal retention clips  610  inserted into retention clip slots  515  formed into the base  500 . The retention clips  610  can also hold a base into a P-Bay chassis  700  and provide increased vibration control. 
   As seen in  FIGS. 2 and 3 , latching mechanism  200  comprising upper and lower locking points for holding the base in a P-Bay chassis is securely attached to one end of the base. The lower locking point comprises an engagement lug  210  and the upper locking point comprises at least two engagement shoulders  220 . The latching mechanism can form a carrier handle  240  and be attached to the base  500  using one or more fasteners such as a machine screw  516  inserted through a hole  255  and set into the base  500 . The carrier handle can be ergonomic in design to facilitate ease of use. 
   The latching mechanism  200  has a lever  242  rotatably mounted on a pivot  260  so as to rotate between an open position  241  and a closed position  251 . In one example a lever  242  in a fully open position  241  is oriented at 90° from a fully closed position  251 . Lower engagement lug  210  and the upper engagement shoulders  220  project in opposite directions from opposite ends of the lever. The lower engagement lug  210  and the upper engagement shoulder  220  may be offset from the rotatable mount  260 . An offset causes a general U shape in the handle as a path through its lower engagement hug  210 , the pivot point  260  and the upper engagement shoulder  220  is not linear. 
   The lower engagement lug  210  mates with a lower cutout  710  in a P-Bay chassis  700 , securing the carrier  100  into the P-Bay chassis  700  when the lever  242  is in the closed position  251 . In one embodiment, the lower engagement lug  210  engages the lower cutout  710  while the lever  242  is less than fully closed. 
   The upper engagement shoulder  220  is attached to the top of a release tab  230 . The release tab  230  is flexibly secured to the lever  242  and downwardly movable. A lower release tab stop plate  231  limits the downward motion of the release tab  230 , and can also serve as a finger hold. An upper stop point  232  limits the upward movement of the release tab. The upper engagement shoulder can engage an upper cutout  720  in a P-Bay chassis while the lever is in a closed position  251 . A downward pressure on the release tab  230  causes downward movement by the tab  330  and the upper engagement shoulders  220 . Downward motion can cause the upper engagement shoulder  220  to disengage from the upper cutout  720  of the P-Bay chassis  700 . If the upper engagement shoulder  220  is disengaged from the upper cutout  720 , the lever  242  is released and can be moved into an open position  241 . 
   Latching mechanism  200  may be formed from a plastic such as ABS or polycarbonate plastic. The latching mechanism can be economically formed using injection molding. The lower engagement lug  210 , the upper engagement shoulder  220 , the release tab  230 , the release tab stop plate  231  and the lever  242  can all be formed from one piece of contiguous molded plastic. A second piece of molded plastic can comprise the handle  240  and securement pads  250  and be attached to the first piece of molded plastic via a rotatable mount  260  such as a pin or other hinge apparatus. The pin can also comprise ABS or polycarbonate plastic. 
   Shoulder slots  248  can be formed in the upper handle  240  to allow the engagement shoulders  220  to reach a fully closed position  251 . The shoulder slots  248  can also serve to limit lateral movement of the latching mechanism lever  242  while the latching mechanism lever  242  is in the closed position  251 . Each engagement shoulder  220  formed into the lever  242  should have a corresponding slot  248  formed into the handle. 
   The electromagnetic interference (EMI) shield  400  is mounted between the latching mechanism  200  and the base  500  and substantially perpendicular to the base  500 . When the carrier  100  is inserted into a P-Bay chassis  700 , the EMI shield  400  effectively creates a tight EMI seal in the front of the P-Bay chassis slot  800  by spanning any empty space and contacting an adjacent drive. Use of an EMI shield  400  can reduce the need for a separate EMI door on the chassis. The EMI shield  400  comprises an electrically conductive metal such as steel formed into a front panel  420  and a side panel  430 . The side panel  430  is essentially perpendicular to the front panel  420 . The panels can have vent holes  421  to allow airflow through the EMI shield  400 , the airflow being conducive to cooling an operational disk drive  625  mounted in the carrier  100 . The vent holes do not affect EMI shielding properties. The EMI shield can be mounted to the base with a fastener such as a machine screw through an EMI shield mounting hole  415  or other known fastening means, such as riveting. 
   The EMI shield  400  can be grounded to the chassis with one or more finger clips  410  mounted in finger clip slots  425 . The finger clip slots  425  are formed into the side panel  430 . The finger clips can be fashioned from an electrically conductive material with spring like characteristics, such as stainless spring steel. Generally, the finger clips form a spring loaded arc that compresses when perpendicular pressure is applied to the arc. As a carrier  100  is inserted into a P-Bay chassis  700 , a finger clip  410  contacts the chassis  700  or an adjacent carrier and compresses. The force of the compression against the contact point causes a mechanical and electrical connection. The mechanical connection provides additional stability to the drive. The electrical connection provides a low insertion force ground to the carrier  100  and hard drive  625  mounted therein while the carrier  100  is being inserted into the chassis  200  and before a disk drive  625  connector mates with a high speed back plane (HSBP)  810 . Grounding the carrier  100  before contact with the HSBP  810  provides a conductive path providing for electrostatic discharge into the chassis  700  instead of the HSBP  810 . The finger clips  410  may be replaceable to extend the useful life of the EMI shield  400 . 
   A user can install a hard drive  625  into a P-Bay chassis by mounting an original equipment manufacturer (OEM) disk drive into the base  500 . In one embodiment the disk drive  625  is mounted using two screws  514  through the upper surface  524  of the base  500  and two screws  514  through the lower surface  520  of the base  500 . The carrier is inserted  730  into a P-Bay chassis slot  800  with the lever  242  in an open position (lever is at an angle greater than 0° and less than 90° to the carrier handle). A user can depress the release tab  230  by applying downward pressure, and fully insert the carrier  100  into the P-Bay chassis  700  causing the disk drive connector  626  to engage with the HSBP  810 . The user can then move the lever  242  into the closed position (˜0°). As the lever  242  is closed the lower engagement lug  210  will insert into a lower cutout  710  latching the bottom of the carrier  100 . The user allows the release tab  230  to return up to its rest position causing the upper engagement shoulder  220  to engage an upper cutout  720  thereby latching the top of the carrier to the P-Bay chassis  700 . As the carrier  100  proceeded into the P-Bay chassis  700 , the finger clips  410  tightly contact an adjacent carrier in an adjacent P-Bay chassis slot  800  grounding the carrier  100  before the disk drive connector engaged the HSBP  810 . 
   The invention may provide advantages that include improved vibration control, ease of use for a technician swapping drives, limited horizontal movement of a carrier, excellent EMI shielding and less restricted air flow for cooling of disk drives. 
   Other embodiments are within the scope of the following claims.