Patent Document

CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority from provisional No. 60/286,732, dated Apr. 25, 2001. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to an environmental chamber for testing hard drives. More specifically, the present invention relates to a fixture for securing and testing a hard drive while in an environmental chamber. 
     BACKGROUND OF THE INVENTION 
     Computer hard drives are generally subjected to a “burn-in” testing procedure conducted in an environmentally controlled test chamber. These chambers are designed to isolate the drive from vibrations, from temperature changes, and from humidity changes so that the drive manufacturer can obtain accurate performance test results. 
     Computer hard drives are also usually subjected to thermal testing or environmental conditioning testing during the design and prototyping phases of the manufacturing process. This testing, also known as “final verification” testing, is also typically conducted in large environmental test chambers. During these tests, it is desirable to have controlled and stabilized air temperature and airflow rate around the devices under test. The test temperature and airflow rate are selected by the manufacturer to simulate the thermal stress range of conditions that the device under test is realistically expected to experience in its useful life. Alternatively, the test temperature and airflow may be selected to include some multiple of the worst expected conditions. These tests can provide a valuable tool to verify product quality and reliability and to assure that the hard drives meet industry standards. 
     Typical hard drive test fixtures in the prior art are precision machined to close tolerance, making them relatively expensive to fabricate. Furthermore, prior art test fixtures are typically built to handle only one type of hard drive. Consequently, there is a need in the art for a low-cost hard drive test fixture, and for a fixture which is adaptable to accommodate disk drives of varying sizes. 
     BRIEF SUMMARY OF THE INVENTION 
     Accordingly, the present invention is a test fixture for supporting a hard drive during testing. The test fixture can be used to store hard drives undergoing testing, and can be adapted for insertion into an environmental testing chamber. The test fixture includes a pan, a test card coupled to the pan, and a bearing surface for guiding a hard drive to the test card. 
     In one embodiment, rails are attached to the base of the pan for providing structural support to the pan and to provide a bearing surface for positioning of the hard drive. A connection card is located in place between the rails and is adapted for connection to the hard drive. The test fixture also includes an ejection rod for facilitating removal of the hard drive from the test fixture. 
     In an alternate embodiment, the test fixture includes a pan, a test card coupled to the pan, a first bearing surface coupled to the pan, and a second bearing surfaced coupled to the pan. The first and second bearing are each adapted to guide a hard drive of a particular size to the test card. In this configuration, the test fixture is easily adapted to test hard drives of varying sizes. 
     While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, wherein is shown and described only the embodiments of the invention, by way of illustration, of the best modes contemplated for carrying out the invention. As will be realized, the invention is capable of modifications in various obvious aspects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is a top view of a hard drive test fixture, according to one embodiment of the present invention. 
     FIG. 1B is an elevated rear view of a hard drive test fixture, according to one embodiment of the present invention. 
     FIG. 2A is a perspective view of a hard drive test fixture, according to one embodiment of the present invention. 
     FIG. 2B is an elevated side view of a hard drive test fixture, according to one embodiment of the present invention. 
     FIG. 3 is an elevated front view of a roller of the hard drive test fixture of FIGS. 1A and 1B. 
     FIG. 4 a  shows an elevated rear view of an array of hard drive test assemblies. 
     FIG. 4 b  is an overhead planar view of a hard drive test assembly engaged to a shelf of an environmental test chamber. 
     FIG. 5 is a side perspective view of a hard drive used in one embodiment of the present invention. 
     FIG. 6 a  shows a sectional view of a hard drive test assembly according to a second embodiment of the present invention. 
     FIG. 6 b  shows a sectional view of a rail according to a second embodiment of the present invention. 
     FIG. 6 c  shows a sectional view of a hard drive test assembly according to a second embodiment of the present invention. 
     FIG. 6 d  shows an overhead planar view of an ejection plate. 
    
    
     DETAILED DESCRIPTION 
     As shown in FIG. 1A, the present invention is a test fixture  10  specially adapted to support a hard drive during testing and to interface thereto. The subject invention is especially suited for use within an environmental chamber, but is easily adapted to cooperate with racks or storage cabinets that are generally known in the art. 
     As shown in FIGS. 1A and 1B, in one embodiment, a pan  12  forms the “backbone” of the fixture  10 . Preferably, the pan  12  is fabricated from nonmagnetic stainless steel. Two bends  15  extend longitudinally along the pan stiffening the pan  12 . Airflow holes  11  are punched in the pan  12  in a pattern generated to maximize the flow of air through and around the inserted hard disk drive  16  (shown by dashed lines in FIGS.  2 A and  2 B), while maintaining adequate stiffness to provide rigidity. 
     Connected to the pan  12  is a bearing surface which serves to guide a hard drive  16  during insertion into the fixture  10 , and to locate the hard drive  16  during testing. FIGS. 1A,  1 B,  2 A, and  2 B show one embodiment, wherein the bearing surface includes a plurality of rails in cooperation with a plurality of rollers. It can be appreciated by one skilled in the art, that the bearing surface can also be comprised of other structural components or comprised of multiple structural components working in cooperation to guide and locate a hard drive  16  within the fixture  10 . 
     Screws  10  are positioned to fix the locations of the rails  18  on the pan  12 . In the preferred embodiment, the rails  18  are positioned by two screws and two dowel pins, with the dowel pins determining the position on the pan  12 . The rails  18  are fabricated preferably from a dissipative plastic material, for example (RTP 387 TFE 10) carbon fiber filler PTFE (polytetrafluoroethylene) lubricated polycarbonate, available from RTP Imagineering of Winona, Minn. 
     Preferably, each rail  18  is identical, thereby reducing manufacturing costs. In one embodiment, the rails are generally T-shaped and are positioned so that a testing sight is defined between two rails. The rails define generally orthogonal first  24  and second  26  surfaces which support and guide a hard disk drive  16  as it is inserted within the fixture  10 . Each rail  18  also includes a slot  20  for locating and supporting a test card  22 . The rail  18  also has a plurality of recesses  28  wherein a roller is disposed. 
     The rollers cooperate with the rail  18  to guide and locate a hard drive  16 . In one embodiment, two types of rollers, idler rollers  30  and pressure rollers  32 , are used. FIG. 3 shows an elevated view of a pressure roller  6 . The sleeve  36  for the pressure rollers  32  is fabricated from a rather low durometer hardness material, such as a neoprene or urethane, for example. The pressure rollers  32  protrude slightly from the rail  18 . The pressure rollers  32  protrude approximately 0.060 inch from the surface of the rail  18 , and it is capable of compressing about 0.030 inch. Alternatively, the pressure roller  32  can also be spring biased. 
     The idler roller  30  includes a brass core  34 . The sleeve  36  of the idler rollers  30  is pressed on or glued to the core and is fabricated from a hard plastic such as POMOLUX or stainless steel. The idler rollers  30  protrude slightly from the rail  18 . In one embodiment, the idler rollers  30  protrude approximately 0.030 inch from the right (as shown in FIG. 2A) vertical face of the rail  18 . 
     In one embodiment, as shown in FIGS. 4 a  and  4   b , the test card  22  is disposed in between a pair of rails  18  and is adapted to slip into the slot  20  in a loose fit manner. In one embodiment, the test card  22  has about 0.015-0.030 inches of play parallel to the surface of the pan  12 . This limits the vertical excursions permitted for the test card  22 . The test card  22  includes an interface which couples to a hard disk under test, and enables the test card to communicate with the hard disk. The test card also communicates with a hard disk testing device (not shown). As can be readily appreciated by one skilled in the art, the test card is typically custom fabricated to interface with the specific hard disk drive  16  undergoing testing. Consequently, a number of different test cards can be used in conjunction with the subject invention. The test card is slidably removable from the rails so that it is easily replaced by a different test card. 
     As shown in FIGS. 1A and 2A, in one embodiment, the fixture  10  includes an ejection mechanism to disconnect a hard disk drive  16  from the interface on the test card  22  and to partially expel the hard disk drive  16  from the fixture  10 . The ejection mechanism includes an ejector rod  38 . The ejector rod  38  extends laterally across the pan and engages guide holes  43  located on bends  15 . The ejector rod  38  has a back end  40  located adjacent to the test card  22 . The back end  40  is shaped to enable a portion thereof to extend through the test card  22  to contact a hard disk  16  attached thereto. The test card  22  is provided with a hole in an appropriate location to allow the back end  40  to travel therethrough. A rubber bumper  42  is connected to the back end  40  for contacting a disk drive. The bumper  42  is made of a material such as a soft urethane that will not mar the drive as it is pulled against it to disengage the drive from the test card  22 . 
     In one embodiment, as shown in FIG. 4 b , the physical position of the drive is controlled by the first  24  and second surface  26  of the rail  18 , the bumper  42 , the test card  22 , the idler rollers  30  and pressure rollers  32 . The rollers  30 ,  32  contact the hard disk drive  16  sides generally at the ANSI standard location of the mounting screw holes  23 . FIG. 5 shows a perspective view of a hard drive  36 , having mounting screw holes  23 . The hard disk drive  16  is inserted into the feature and is guided to the test card, enabling the test card  22  to interface with the hard disk drive  16 . After a hard drive is successfully interfaced with the test card, a testing circuit is completed allowing LED  7  to light up. 
     FIG. 4 a  shows an array of the hard drive test fixture  10 , according to one embodiment of the present invention. As shown in FIG. 4 a , the pan  12  accommodates five hard disk drives longitudinally thereon, and is stacked twelve pans high in a frame, to create an array of sixty drives. The sixty-drive array so constructed would occupy a box about 2×2×2 feet. An array is constructed incorporating front and rear “angle iron” frames  44  that define the perimeter of their respective locations. Side panels  46  are attached to the frames  44  by several screws. 
     In one embodiment, each of the pans  12  is extended to accommodate five hard disk drives  16  and secured to the proper location on the side panels  46  by screws. The rear panel  48  is secured to the rear frame  44  by the same screws that hold the side panel  46 . The rear panel  48  is fabricated to carry the appropriate interconnections to the outside, fans, devices for heating or cooling, and whatever equipment a test box or an environmental chamber requires to execute its desired functions. The basic building blocks for testing sixty drives can easily be stacked together to build testers of 120, 180, 240, 360, or greater, drive capacity by simply constructing a mounting framework  44 . 
     FIGS. 6 a  and  6   b , shows one embodiment of the subject invention where the subject fixture  50  is configurable to accommodate disk drives of varying sizes. As shown in FIG. 6, a third surface  52  of the rail  18  can be utilized as a bearing surface for guiding smaller hard disk drives. Additionally, inserts  53  can be attached to the rail  18  so that the testing area can be made to accommodate disk drives of varying sizes. 
     As shown in FIGS. 6 c  and  6   d , the ejection mechanism can also accommodate hard disk drives of varying sizes. An ejection plate  54  is coupled to the back end  40  of the ejector rod  38 . The ejection plate  54  travels through the test card  22  along a slot  56  extending through the testing card  22 . Activation of the ejector rod  38  would also activate the ejection plate, the ejection plate  54  contacting the disk drive  16  and causing it to disengage with the test card  22 . 
     While the present invention has been described with reference to several embodiments thereof, those skilled in the art will recognize various changes that may be made without departing from the spirit and scope of the claimed invention. Accordingly, this invention is not limited to what is shown in the drawings and described in the specification but only as indicated in the appended claims. Any numbering or ordering of elements in the following claims is merely for convenience and is not intended to suggest that the ordering of the elements of the claims has any particular significance other than that otherwise expressed by the language of the claim.

Technology Category: g