Abstract:
A means is provided for packaging disc drives and other information-storage devices in a manner that reduces transmittal of shock to the packaged device. The device is placed in a static-dissipative package comprising an upper and lower portion, each of which is externally ribbed to absorb shock. Further anti-impact protection is provided by internal buttresses that cushion the packaged device. The package is preferably a unitary article molded from PVC plastic sheeting, with the upper and lower portions joined at an accordion-like hinge. The upper and lower portions nest together at the peripheral edges, providing a labyrinthine path (in effect, a seal) that prevents passage of contaminants. Shock transmittal (relative to a bare drive) is reduced by a factor of approximately 5-7.

Description:
The benefit of the filing date of Provisional Application 60/139914 (filed Jun. 17, 1999) is claimed. 
    
    
     BACKGROUND 
     The field of this invention is protective packaging for disc drives and other information-storage devices. More specifically, the invention concerns a method and device for protecting disc drives and other information-storage devices from damage resulting from impact and electrostatic discharge during shipment and other non-operating activities. 
     The principal cause of failure of disc drives is handling damage, not operational failure (so-called disc crashes). Handling damage to a disc drive occurs as a result of bumping or dropping the disc drive or causing it to come in contact with a hard surface. Such handling damage is classified as disc slip, head slaps, or gross cosmetic damage. Handling damage occurs during freight transit, carton handling, actual product handling, and product-system integration. 
     Generally similar damage occurs in the case of other information-storage devices, such as tape drives and optical drives. Additional non-operational damage to disc drives and similar devices occurs as a result of electrostatic discharge, and it is typical to ship devices in an anti-static (static-shielded) bag (also known as an ESD bag) to prevent or reduce such damage. 
     Current non-operational shock specifications for Seagate desktop information storage devices call for ability to survive 300 g at 2 ms. For high-end products, the specification is approximately 150 g at 2 ms. At shock levels in excess of the specification, it is considered that a drive will suffer physical damage. Handling actions such as those described above (e.g., freight transit) often impart shock in excess of the g levels specified above, leading to return of damaged products for repair or replacement under product warranties, at manufacturer expense. It is believed that this problem and the expense due to handling damage has existed for many years in the disc drive industry. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the invention to reduce handling damage and the expense resulting therefrom by improving anti-shock protection for disc drives and other information-storage products. 
     It is an object of the invention to permit a package containing a disc drive or other information-storage device to be subjected to higher than 300 g at 2 ms shock levels while the disc drive or other information-storage device within the package receives less than 200 g at 2 ms shock levels. 
     It is a further object of the invention to provide anti-static protection that will eliminate need for use of an anti-static (static-shielded) bag for the disc drive or other information-storage device within the package. 
     The invention provides a means for packaging disc drives and other information-storage devices in a manner that reduces transmittal of shock to the packaged device. The device is placed in a static-dissipative package comprising an upper and lower portion, each of which is externally ribbed to absorb shock. Further anti-impact protection is provided by buttresses that cushion the packaged device. The package is preferably a unitary article molded from PVC plastic sheeting, with the upper and lower portions joined at an accordion-like hinge. The upper and lower portions nest together at the peripheral edges, providing a labyrinthine path (in effect, a seal) that prevents passage of contaminants. Shock transmittal (relative to a bare drive) is reduced by a factor of approximately 5-7. 
    
    
     DESCRIPTION OF DRAWINGS 
     FIG. 1 is a perspective drawing of an opened package of the invention, from a vantage point above the left proximal end of the lower portion of the package. 
     FIG. 2 is a plan view looking down at an opened package of the invention, with the lower proximal end of the package lowermost and the upper proximal end uppermost. 
     FIG. 3 is a plan view looking down at the upper portion of the closed package with the proximal end of the package to the right. 
     FIG. 4 is a side view of the closed package with the proximal end to the right. 
     FIG. 5 is an end view of the distal end of the closed package. 
     FIG. 6 is a plan view looking down at the lower portion of the closed package with the proximal end of the package to the right. 
     FIG. 7 is a side view of the closed package with the proximal end to the left. 
     FIG. 8 is an end view of the proximal end of the closed-package. 
     FIG. 9 is a side view cross-sectional detail of the hinge located at the distal end of the package, showing adjacent portions of the package, with the upper portion of the package to the right and the lower portion to the left. The package if fully open in this view, with the upper and lower portions 180 degrees apart. 
     FIG. 10 is also a side view cross-sectional detail of the hinge located at the distal end of the package, showing adjacent portions of the package. In this view the upper portion of the package has been rotated to the left (counterclockwise), relative to FIG. 9, showing the package closed and the flange member of the upper portion of the package nested into the flange member of the lower portion of the package. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention can be appreciated by considering the design of Seagate&#39;s commercial Seashell™ package for a disc drive. Referring to FIG. 1, a perspective drawing of the opened package of the invention from a vantage point above the left proximal end of the lower portion of the package, it is seen that clamshell package  10  comprises an upper molded-sheet portion  12  and a lower molded-sheet portion  14 . Upper and lower molded-sheet portions  12  and  14  are joined at their distal ends by an accordion hinge  15 . Hinge  15  is shown more advantageously in FIGS. 9-10, in cross-section, and is discussed in greater detail below. 
     Upper and lower molded-sheet portions  12  and  14  are generally congruent to one another, in the sense that their dimensions are approximately the same and they fit together in approximate mirror image form. However, as will appear, structural differences between upper and lower molded-sheet portions  12  and  14  (in particular, how they interlock) make them not true mirror images of one another and not fully congruent. 
     In the commercial Seashell™ embodiment of the invention, the package is a unitary, one-piece article, which is integrally formed by vacuum molding a plastic sheet. This is considered preferably from a manufacturing cost standpoint. However, the package may be manufactured as a two-piece article also, with or without a hinge. For example, if the package is manufactured as a two-piece article without a hinge, upper and lower molded-sheet portions  12  and  14  may be taped together. However, this is considered a non-preferred embodiment, since it calls for using two molds and increases parts count as well as requiring a tape application step. 
     Clamshell package  10  of this embodiment of the invention was manufactured by vacuum molding approximately 0.020 to 0.024 inch thick polyvinyl chloride (PVC) sheet material. (Different exemplars were produced at various such thicknesses. The 0.20 thickness is considered to be preferred). The material used was Penta-stat™ PVC manufactured by Klockner. This material is static-dissipative, which permits avoiding the cost of an ESD bag that would otherwise be needed. The vacuum molding process was entirely conventional and involved use of techniques well known to persons of skill in the art. Other plastic materials besides PVC were tried, but packages made from PVC provided the best shock resistance of the materials tested. 
     Referring now to FIG. 2, a plan view showing the inside of the package as the package appears when it leaves the vacuum mold, it is seen that a lower molded-sheet portion flange member  16  extends generally laterally all around lower molded-sheet portion  14  of package  10 . Similarly, an upper molded-sheet portion flange member  18  extends generally laterally all around upper molded-sheet portion  12  of package  10 . Each flange member has a stepped structure, shown advantageously in FIGS. 9-10, so that flange member  16  has an inner lateral portion  16   a,  an intermediate vertical portion  16   b,  and an outer lateral portion  16   c,  while flange member  18  has an inner lateral portion  18   a,  an intermediate vertical portion  18   b,  and an outer lateral portion  18   c.  Lower molded-sheet portion flange  16  has two tabs  20  extending proximally therefrom. Upper molded-sheet portion flange  18  has two tabs  22  extending proximally therefrom. When package  10  is closed, tabs  20  engage against tabs  22  with an overlap, as shown advantageously in FIG. 3, a plan view of the closed package. Tabs  20  and  22  cooperate to facilitate opening the package when it is closed; the user simultaneously pushes tab(s)  20  down and  22  up to separate the upper and lower molded-sheet portions of the package at the proximal end. 
     In the first commercial Seashell™ embodiment of the invention, the package is approximately 5.25 inches wide, 7.6 inches long (including tabs), and 1.5 inches high (including ribs). The outer lateral flange members extend laterally outward approximately 0.25 inches, and the tabs extend another approximately 0.25 inches longitudinally outward. This package accommodates a disc drive (or other information-storage device) approximately 4 inches wide, 5.75 inches long, and 1.25 inches high. 
     Returning to FIG. 1, it is seen that lower molded-sheet portion flange member  16  leads via the above-described stepped structure to lower dome  24 , which is a half disc drive height recess in the package. Upper molded-sheet portion flange member  18  leads to a complementary stepped structure for upper dome  26 , which is also a half disc drive height recess in the package. Accordingly, a labyrinthine path, shown more advantageously in FIG. 10, is provided to block ingress of contaminants from outside the package to the disc drive to be stored within domes  24  and  26  (and it also blocks escape of fluids, if any, from the drive stored in the domes). At the same time, a structure is provided by which the upper dome fits with the lower dome tightly and keeps the package closed with a so-called male-to-female fit of the flange members. 
     The flange member structure “leans” slightly inward at the upper part of the steps, so that when the upper and lower molded-sheet portion are pressed together a deformation and detent effect occurs, holding the closed package together. The operation of this structure is further described below in connection with hinge  15 , and FIGS. 9-10 show hinge  15  and the flange members in cross-section. As shown in FIG. 10, when package  10  is closed the upper extremities of intermediate vertical portions  16   b  and  18   b  are slightly to the left of the lower extremities thereof, causing a tight fit and a detent effect tending to maintain closure. A similar cross-section for the flange members obtains all around the rest of the periphery of the package, although without any hinge  15  as shown in FIG.  10 . Thus, for material (e.g., dirt) to enter or exit the closed package the material would need to traverse the labyrinthine path defined by elements  16   c / 18   c,    16   b / 18   b,  and  16   a / 18   a  of flange members  16  and  18 . 
     While the labyrinthine path shown here is, in effect, merely a partly straightened-out Z, other non-straight-line and/or more complex paths may be used to exclude contaminants, such as a Z (not straightened out), W, M, or Q, so long as the path is effective to exclude undesirable material and yet permissive of closure and opening of the package. 
     Domes  24  and  26  are generally (but not fully) both congruent and mirror images. Both domes have approximately the same dimensions and they fit together in complementary fashion along the flange members, so as to define a compartment in which to place the disc drive or other storage device being packaged. Both domes are characterized by longitudinal and transverse vertical dome walls with an undulating, sine-wave-like cross-section. These structures are referred to hereinafter as buttresses  28 . Both domes also have generally similar, riblike structures  30  extending vertically outward therefrom. 
     Turning first to the ribs, by referring to FIG. 4 it is seen that a plurality of rounded ribs  30  extend out from upper and lower molded-sheet portions  12  and  14  of the package, and more specifically from domes  24  and  26 . Rounded ribs  30  are resilient and deform inward upon impact. Therefore they absorb shock, thereby protecting the disc drive stored within the package. In the commercial embodiment of the Seashell™ package, it was found that five upper ribs and five lower ribs, transversely disposed on domes  24  and  26  as shown in FIGS. 3-4 (and described in the succeeding paragraph), performed satisfactorily to meet desired shock resistance specifications. It appears that the optimum arrangement of ribs must be determined empirically on a case-by-case, trial-and-error basis. It has not been possible thus far to develop a rationale for determining best rib arrangement, and therefore no substitute has yet been found for a primarily empirical approach. It does appear, however, that more than one satisfactory arrangement can be devised that will perform within shock specifications, so that to some extent it is a matter of design choice or aesthetics what specific arrangement to use. 
     As indicated, disposed on the transverse and longitudinal vertical dome walls around the periphery of upper and lower domes  24  and  26  are a series of rounded, buttress-like structures  28 , which are adapted to cushion the disc drive within the domes. These rounded buttress-like structures are resilient and thus act as springs to absorb shock and cushion the disc drive to prevent it from rattling around in the package when the package is subjected to impact from the ends or sides of the package. Preferably, buttresses  28  press against the disc drive and hold if firmly in place at all times. Each dome&#39;s buttresses preferably extend vertically half the height of the disc drive. 
     The inwardly extending lateral extremities of the buttresses define a compartment within the domes, whose width and height dimensions correspond to the width and height of the disc drive to be stored in the package. The number of buttresses extending inward should be at least two per side, since two points (here, points of tangency) define a line in a Euclidean plane. Other than that, the number and location of the buttresses is a matter of design choice and of aesthetic considerations. 
     Also, preferably, the buttresses are structured in a generally sine-wave-like shape, so that their portions not projecting convexly and inward into the domes project outward and convexly away from the domes. Thus, the buttress formations at the proximal and distal ends of the domes both project inward to cushion the disc drive within the domes at one part of the “sine wave” and they project somewhat into the flanges&#39; inner lateral portion a half cycle farther along the “sine wave”. Hence, when the package lands on an end at an angle the buttresses&#39; outwardly projecting parts provide some cushioning. In the case of the transverse extremes of the domes (i.e., the right and left sides), the buttress formation interacts with ribs  30 . The inwardly projecting parts of the buttresses are located between the ribs. The outwardly projecting parts of the buttresses preferably coincide in shape and location with the ribs and thus they vertically extend the rounded projections of the ribs inward from the dome roof to the flange members. Hence, when the package lands on a side at an angle the outwardly projecting parts of the buttresses provide some cushioning, in the same manner as the ribs do. 
     In addition, tabs  20  and  22 , as well as hinge  15 , are resilient and thus capable of further absorbing impact directed at the ends of the package. 
     It is desirable that the ribs extend all of the way across the domes, to provide maximum protection against impact. However, they should not extend transversely so far that they interfere with the effect of the labyrinthine path of the flange members. If they did so, then the outwardly projecting buttress vertical extension of the ribs could open up a path around the seal that the flange members provide against passage of contaminants. It is considered that approximately 0.1 inch clearance between the end of the ribs/buttresses and the vertical portion of the flange (i.e., element  16   b  and  18   b ) is appropriate for this purpose. Such a clearance can be observed advantageously in FIG. 1, where it is seen that the vertical buttress walls do not extend all of the way to the intermediate vertical portions of the flanges (elements  16   b  and  18   b ). 
     In the first commercial Seashell™ embodiment, the ribs are semicircular in cross-section, approximately 0.5 inches in diameter, and project outward from the dome approximately 0.25 inches. There are five ribs transversely disposed on each of the roof domes, extending transversely the entire width of the roof and to approximately 0.1 inches of the intermediate vertical flange portions. The longitudinally proximal edge of the first (i.e. most proximal) rib approximately coincides with the proximal end of the compartment defined by the proximal inwardly projecting buttresses. Likewise, the longitudinally distal edge of the fifth (i.e., most distal) rib approximately coincides with the distal end of the space or compartment defined by the distal inwardly projecting buttresses. The third (central) rib is approximately longitudinally equidistant from the proximal and distal ends of the same compartment. The remaining (second and fourth) ribs are symmetrically disposed slightly more toward the ends of the roof than toward its center, so that the respective distances between the central longitudinal (transversely extending) axes of the first, second, and third ribs are approximately 1 inch and 1.5 inches. The five buttresses extending laterally outward from each side of each dome, and coinciding with the ribs, each define four buttresses extending laterally inward. Each end of a dome has five buttresses extending outward and four buttresses therebetween extending inward. 
     The ribs or the flat areas between ribs optionally contain small conelike projections or complementary recesses, to facilitate stacking the packages. Flat areas between ribs may advantageously be used to contain logos, brand names, etc. 
     In another, less preferred embodiment, the dimensions of the package were similar, except that the five ribs transversely disposed on each of the roof domes, extending transversely the entire width of the roof and to approximately 0.1 inches of the intermediate vertical flange portions, were spaced such that the two ribs flanking the centermost rib had their longitudinal axes separated approximately 1 inch from the longitudinal axis of the centermost rib, and such axes were separated from the axes of the most distal and most proximal ribs, respectively, by approximately 1.5 inches. In still another, less preferred embodiment, the dimensions of the package were similar, except that the five ribs transversely disposed on each of the roof domes were spaced approximately equidistant from one another (each longitudinal axis approximately 1.25 inches apart from the next longitudinal axis). 
     Referring to FIGS. 9-10, which show cross-sectional views of the hinging along a longitudinal vertical section of the package, it is seen that hinge  15  is an accordion-like or pleated structure. As shown in FIG. 9, hinge  15  is located between the distal ends of the package portions, connecting the distal ends of flanges  16  and  18 . As shown in this embodiment, hinge  15  in cross-section resembles the alphanumeric characters  2  S  2  S connected together at their respective lower, upper, and lower adjacent terminal extremities. Other possible hinge structures may be devised with cross-sections resembling W&#39;s, M&#39;s, Z&#39;s, etc. The purpose of this pleated or folded structure, however embodied, is to flexibly vary the longitudinal dimension of the hinge in order to permit the flange member of the upper molded-sheet portion to be lifted up directly above, and clearing, the flange member of the lower molded-sheet portion when the hinge is rotated in order to nest the flange members, and at the same time to permit a state of equilibrium to obtain when the package is fully open or fully closed, as further described below. 
     In the fully closed position of clamshell package  10 , upper and lower molded-sheet potions  12  and  14  are in registration with one another; the domes and buttresses of each portion are vertically aligned; and the step structure of the upper flange member is nested into the step structure of the lower flange member. Thus, element  18   c  is directly over and in registration with element  16   c.  Element  18   b  vertically parallels and engages element  16   b  and is surrounded thereby. Element  18   a  is directly over and in registration with element  16   a.  Hinge  15  is folded up in a manner permitting this configuration of the upper and lower molded-sheet potions. 
     In the fully open position of clamshell package  10 , with the upper and lower molded-sheet potions extending in 180 degree opposite directions, element  18   c,  the outer lateral portion of flange member  18  of upper molded-sheet portion  12 , is at approximately the same height as element  16   c,  the outer lateral portion of flange member  16  of lower molded-sheet portion  14 . At the same time, element  18   a,  the inner lateral portion of flange member  18  of upper molded-sheet portion  12 , is raised substantially above the elements of lower molded-sheet portion  14 . Hinge  15  is opened up to a maximum extent. 
     Each of these positions represents a static equilibrium, so that the resilient, deformable elements of the package are in “energy wells” in each configuration. During the transition from one configuration to the other, mechanical energy is applied to the system, the hinge stretches and stores energy, and it subsequently retracts into a lower-energy configuration and releases energy as low-grade heat upon and after package closure (and also after being opened from a fully closed position, when the reverse cycle occurs). When the package is fully closed and the flange member of the upper molded-sheet nests into the flange member of the lower molded-sheet portion, the result is that the upper and lower molded-sheet portions are engaged firmly against one another and a labyrinthine path is established between the inside of the domes and the outside of the package, which prevents ingress of contaminants that could damage the disc drive (and also prevents escape of fluids, if any). The foregoing considerations are reflected in the choice of the hinge structure shown in FIGS. 9-10. It is considered that any hinge structure would be equivalent for this purpose if it permitted establishment of these equilibria and stretched appropriately to allow clearance of the respective edges of the flange members when swung between open and fully closed positions (i.e., so that the inner lateral portion of the upper flange member can slip past the outer lateral portion of the lower flange member). 
     Hinge configurations of this general type are known to manufacturers of plastic packages, and they have been used with other types of package than that of the invention, for example, in food containers. See U.S. Pat. No. 5,242,696, disclosing a reclosable polymeric (polyethylene terephthalate) cheese package utilizing a generally similar hinge for the purpose of biasing the package lid toward an open position. However, it is believed that such hinges have not been used in connection with shock resistant packages for disc drives and other information-storage devices, and in particular for manufacturing a package for a disc drive or other information-storage device and one that is stable in both its open and closed positions because each such configuration is in an energy well. 
     The package of the invention was compared with other packages in regard to shock resistance, using a non-operating Seagate model No. ST31024A disc drive, accelerometer-equipped on appropriate axes. A bare drive dropped 12 inches to a hard surface received shock in excess of 1060 g, while a Seashell™-packaged drive registered less than 140 g for the same 12 inch drop. The bare drive subjected to a 120 degree topple sustained in excess of 1100 g while the Seashell™-packaged drive registered less than 200 g. A 20 kV “zap” test indicated that the Seashell™-packaged drive met current anti-static specifications as well as a drive in an ESD bag did. Other tests indicated that a Seashell™-packaged drive registered less than 200 g for 1.5 foot drops onto a thin ESD mat and 2 foot drops onto cardboard. The Seashell™ package also met test specifications for contamination entry/exit. 
     It is contemplated that the proximal end of the package will be covered at least in part with a label that will further hold together the upper and lower portions of the package. 
     While the invention has been described in connection with specific and preferred embodiments thereof, it is capable of further modifications without departing from the spirit and scope of the invention. This application is intended to cover all variations, uses, or adaptations of the invention, following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains, or as are obvious to persons skilled in the art, at the time the departure is made. For example, as claimed the upper flange member nests into the lower flange member, but it would be equivalent to turn these structures upside down so that the lower flange member nests into the upper flange member. 
     It should be appreciated that the scope of this invention is not limited to the detailed description of the invention hereinabove, which is intended merely to be illustrative, but rather comprehends the subject matter defined by the following claims. 
     As used in the claims, verticality and height are synonymous.