Patent Publication Number: US-6661652-B2

Title: Anti-vibration disk drive cage

Description:
PRIORITY 
     This application claims priority from 1) U.S. patent application Ser. No. 09/661,654, filed Sep. 14, 2000, and entitled, “Anti-Vibration Disk Drive Cage” and 2) U.S. provisional patent application serial No. 60/154,525, filed Sep. 16, 1999, and entitled, “Anti-Vibration Disk Drive Cage,” the disclosures of which are incorporated herein, in their entireties, by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention generally relates to disk drives in computer systems and, more particularly, the invention relates to reducing vibration produced by a rotating disk drive in a computer system. 
     BACKGROUND OF THE INVENTION 
     Disk drives commonly are mounted within a rigid disk cage that is a part of a computer system. To increase data storage capacity, the disk cage often includes several bays for receiving more than one disk drive. For example, well known RAID (redundant array of inexpensive disk) arrays have a plurality of removable disk drives that each are removably coupled within specific bays of a single disk cage. Each disk drive in a RAID array generally includes an interface that couples with a corresponding interface to a main bus on the computer system. The disk drives in many well known RAID arrays are considered to be “hot swappable” since they may be removed from and reinserted into the cage at any time. 
     As the processing speed of computer systems increase, there is a growing need to more rapidly access data on RAID arrays. To that end, disk drives are being developed to rotate at ever higher speeds (e.g., 10,000 revolutions per minute). Although beneficial for rapidly retrieving data, operating the disk drives at such high speeds often produces undesired vibrations that can cause the vibrating disk drive (as well as other disk drives in the RAID array) to malfunction. This vibration is multiplied when each disk drive in a RAID array is vibrating. In fact, the disk drives can vibrate at a resonant frequency that could cause a catastrophic data failure of the entire RAID array. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the invention, a disk cage for use with a computer system includes an interior wall that forms a disk drive chamber, and a spring for reducing the vibration of any disk drives that may be inserted within the disk chamber. The spring is coupled with the interior wall and extends into the disk drive chamber to form a receiving chamber for receiving the disk drive. 
     In preferred embodiments, the drive chamber is substantially rectangular. The spring may be any well known type of spring, such as a leaf spring. 
     In accordance with another aspect of the invention, a disk system includes a disk cage having a spring and an interior wall that forms a disk drive chamber. The disk system also includes a disk drive removably coupled within the disk drive chamber. The spring in the disk cage preferably is coupled with the interior wall and extends into the disk drive chamber to form a receiving chamber. The spring contacts the disk drive to dampen disk drive vibration. 
     In some embodiments, the spring is permanently secured to the interior wall. In other embodiments, the disk cage includes a plurality of additional springs coupled with the interior wall. The disk system further includes a plurality of disk drives removably coupled within the receiving chamber. Each disk drive contacts one spring to dampen disk drive vibration. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and advantages of various aspects of the invention will be appreciated more fully from the following further description thereof with reference to the accompanying drawings, wherein: 
     FIG. 1 schematically shows a computer tower that may be utilized with preferred embodiments of the invention. 
     FIG. 2 schematically shows a disk cage that is configured to receive a plurality of disk drives in accordance with preferred embodiments. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 schematically shows a computer tower  10  having a disk cage (FIG. 2) configured in accordance with preferred embodiments of the invention. The computer tower  10  may be used with a computer system for storing and processing data. In such case, the computer tower  10  may have many computer elements commonly known in the art, such as a microprocessor, random access memory, busses, and other similar elements. It should be noted, however, that although a computer tower  10  is shown, other types of computer systems may be used. 
     In preferred embodiments, the computer tower  10  is a redundant array of inexpensive disks (referred to herein as a “RAID array”) that is utilized to store large quantities of data. The RAID array may be any RAID array known in the art, such as a model number FC5500 Clariion RAID array, available from EMC Corporation of Hopkinton, Mass. Such RAID array implements at least one RAID level and thus, includes a plurality of disk drives for storing a large quantity of data. 
     FIG. 2 schematically shows a disk cage  12  configured in accordance with preferred embodiments of the invention. More particularly, in illustrative embodiments, the disk cage  12  is configured to receive four disk drives  14  within a disk chamber  24 . The drives  14  are hot swappable and thus, each include an interface  15  for electrically coupling with a backplane (not shown) at a rear portion of the disk cage  12 . The disk cage  12  includes a top wall  16 , two side walls  18 , a bottom wall  20 , and a rear wall  22  that together form the disk chamber  24 . The disk chamber  24  also includes a front opening  26  for receiving the disk drives  14 . 
     Four leaf springs  28  preferably are secured (e.g., riveted) to the bottom wall  20  and extend upwardly into the disk chamber  24 . Each leaf spring  28  preferably is utilized to secure one of the disk drives  14  within the disk cage  12 . Accordingly, each leaf spring  28  forms a separate receiving chamber  32  for receiving one disk drive  14 . In alternative embodiments, other types of springs  28  may be used. 
     In other embodiments, each receiving chamber  32  includes two corresponding springs  28 . In particular, in addition to the spring  28  secured to the bottom wall  20 , each receiving chamber  32  includes a second spring  28  that is coupled to the top wall  16  within its respective chamber. Use of two (or more) springs  28  further dampens undesired vibration. 
     The leaf springs  28  are considered to be “permanently” secured to the bottom wall  20  since they are not removable with a minimal amount of force. For example, removing rivets or cutting the springs  28  would remove the springs  28 , but such removal methods are not considered to require a minimal amount of force (i.e., they change the permanent structure of the entire disk cage  12 ). In contrast, as discussed herein, the disk drives  14  are removably coupled within the disk cage  12  since they can be removed manually with a minimal amount of force. In illustrative embodiments, the springs  28  are manufactured from 302 stainless steel full hard having the thickness of about 0.25 millimeters. The spring may have a spring constant of about 30 to 40 pounds per inch. 
     To ensure rigidity, the disk cage  12  preferably is manufactured from cold rolled steel having a thickness of about 0.060 inches. In addition, the disk cage  12  also may include a tension member  30  extending between the top wall  16  to the bottom wall  20 . The disk cage  12  shown in FIG. 2 has a height (i.e., between the top wall  16  and bottom wall  20 ) of about 4.5 inches, a width (i.e., between the side walls  18 ) of about 6.0 inches, and a depth (i.e., between the front opening  26  and the rear wall  22 ) of about 6.0 inches. Of course, it should be noted that in a manner similar to other specifics discussed herein, these dimensions are exemplary and not intended to limit the scope of various embodiments of the invention. 
     Each disk drive  14  shown in FIG. 2 has a height of about 4.0 inches, a width of about 1.0 inches, and a depth of about 6.0 inches. Although not shown, movable clips may be utilized to removably secure the disk drives  14  within their respective locations in the disk cage  12 . Accordingly, when inserted into the disk cage  12 , each disk drive  14  is forced upwardly by its corresponding spring  28 . Guides (not shown) within the disk cage  12  may be utilized to guide each inserted disk drive  14  within the disk cage  12  so that it couples with the backplane. The springs  28  are selected so that vibration is minimized to a reasonable tolerance that does not significantly adversely affect the disk drives  14 . 
     Although various exemplary embodiments of the invention have been disclosed, it should be apparent to those skilled in the art that various changes and modifications can be made which will achieve some of the advantages of the invention without departing from the true scope of the invention. These and other obvious modifications are intended to be covered by the appended claims. 
     Having thus described the invention, what we desire to claim and secure by Letters Patent is: