WO1996034390A1

WO1996034390A1 - An elastomeric bumper which extends from an outer edge of a disk drive housing

Info

Publication number: WO1996034390A1
Application number: PCT/US1996/005779
Authority: WO
Inventors: David B. Knighton; Harold Beecroft
Original assignee: Maxtor Corporation
Priority date: 1995-04-27
Filing date: 1996-04-26
Publication date: 1996-10-31
Also published as: AU5788196A

Abstract

There is a cover plate (30) and a base plate (28) forming a hard disk drive (10). Together the plates define a housing which encloses the disk and accompanying hardware of the disk drive. A clamp (32) has a C-shaped cross section which includes a pair of leg portions (34) adjacent to an outer flange portion of the housing. When the clamp is in an unassembled condition, the distance between the leg portions is less than the combined thickness of the outer flange portion. The leg portions have a plurality of tabs (40) which extend into corresponding slots in the plates to lock the clamp onto the housing. Mounted to the outer edges of the cover and the base plate are a pair of elastomeric strips (60, 64) which absorb shock loads applied to the edges of the disk drive. The strips each have a plurality of studs (70) that are inserted into corresponding notches (72) in the plates.

Description

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

The present invention relates to a clamping device for fastening a cover plate to a base plate of a hard disk drive.

2. DESCRIPTION OF RELATED ART

Most computer systems include a massive memory storage device such as a hard disk drive. Hard disk drive units contain a magnetic disk that is capable of storing a large amount of binary information. The magnetic disk is typically coupled to a hub which is rotated by an electric motor. The drive unit also has a head that magnetizes and senses the magnetic field of the disk. The head is typically located at the end of an actuator arm which can move relative to the magnetic disk. The actuator arm, motor and other components of a typical disk drive unit are relatively small and fragile, and are therefore susceptible to damage when subjected to excessive external loads or vibration. For this reason, hard disk drives are usually rigidly mounted to the housing of the computer system by screws or other fastening means.

Hard disk drives contain programs and other information that are vital to the user. It is sometimes desirable to transfer such information to a different computer system. Transferring programs from-a hard disk typically requires loading the information onto a floppy disk, or sending such information over a phone line. Such methods can be time consuming, particularly if the program is long or there is a large amount of data. There have been developed portable hard disk drives which can be plugged into a slot in the computer. To reduce the amount of possible component damage to the drive unit, the housing and assembly are typically constructed to be quite rugged. These rugged assemblies are typically heavy and bulky, and generally impractical to carry and store.

The Personal Computer Memory Card International Association (PCMCIA) has recently promulgated specifications for portable memory cards which can be plugged into slots within a computer. The PCMCIA standard includes a type I format, a type II format and a type III format, each format being distinguished by a different card thickness. Memory can be added to a computer by merely plugging in an additional card. Similarly, a modem or facsimile (FAX) card can be added to a system with the push of the hand. The standardized format of the cards allow a user to plug the memory card of one computer into another computer regardless of the type or make of either system.

The standardized cards are approximately the size of a credit card and include a connector which mates with a connector in the computer. The small size of the card provides an electronic assembly that is easy to carry and store. It is very desirable to have a hard disk drive unit which conforms with the PCMCIA format, so that the disk drive can be readily carried and plugged into an existing slot of a computer. Such a hard disk card must be rugged enough to withstand the large shock loads that may be applied to the drive.unit. Shock loads may occur by dropping a card, or subjecting the host computer to a large force that is transmitted to the disk drive through the computer housing. It would be desirable to have a hard disk drive that conforms with the PCMCIA format and can withstand large shock loads.

Hard disk drives typically include a cover plate that is attached to a base plate by a plurality of screws or other equivalent type of fastening means. Application serial no. 07/975,008, assigned to the same assignee as the present application, discloses a hard disk drive that conforms to the PCMCIA type III format. The disk drive disclosed in the '008 application includes a plurality of small screws which attach the cover to the base plate of the drive.

It is desirable to provide a disk drive that conforms to the PCMCIA type II format. The type li format requires a card thickness approximately one-half the thickness of a type III card. Screws small enough to meet the type II height requirements would be costly to produce. Additionally, the screws would be relatively weak and would tend to shear under excessive shock loads. It would therefore be desirable to provide a threadless means of attaching the cover to the base plate of a hard disk drive unit which meets the PCMCIA specifications.

SUMMARY OF THE INVENTION

The present invention is a clamp which fastens a cover plate to the base plate of a hard disk drive. Together the plates define a housing which encloses the disk and accompanying hardware of the disk drive. The clamp has a C- shaped cross-section which includes a pair of leg portions adjacent to an outer flange portion of the housing. When the clamp is in an unassembled condition, the distance between the leg portions is less than the combined thickness of the outer flange portion. The clamp is typically pushed onto the housing, so that the leg portions are deflected an amount sufficient to produce a spring force sufficient to clamp together the plates. The leg portions also have a plurality of tabs which extend into corresponding slots in the plates to lock the clamp onto the housing. Mounted to the outer edges of the cover and base plate are a pair of elastomeric strips which absorb shock loads applied to the edges of the disk drive. The strips each have a plurality of studs that are inserted into corresponding notches in the plates. The clamp is small enough to provide a disk drive assembly which complies with the PCMCIA specifications.

Therefore it is an object of the present invention to provide a means of attaching a cover plate to the base plate of a hard disk dri e that complies with the PCMCIA type II format.

It is also an object of the present invention to provide a member which attaches a cover plate to the base plate of hard disk drive and absorbs any shock load applied to the edges of the drive. BRIEF DESCRIPTION OF THE TtRA INGS

The objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, wherein:

Figure 1 is a perspective view of a hard disk drive with a coupling clamp of the present invention;

Figure 2 is a top cross-sectional view of the hard disk drive of Fig. 1;

Figure 3 is an enlarged cross-sectional view of the disk drive taken at line 3-3 of Fig. 1;

Figure 4 is a cross-sectional view of the coupling clamp shown in an unassembled condition;

Figure 5 is a cross-sectional view of an alternate embodiment of the coupling clamp;

Figure 6 is a view similar to Fig. 4 showing an alternate embodiment of the coupling clamp;

Figure 7 is a side view showing a preferred embodiment of mounting a pair of elastomeric strips to the outer edges of the disk drive;

Figure 8 is a sectional view of the elastomeric strip inserted into a corresponding groove of the cover.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings more particularly by reference numbers. Figure 1 shows a hard disk drive card assembly 10 that can be plugged into a computer (not shown) . The assembly 10 includes a housing 12 and a connector 14. In the preferred embodiment, the housing has the dimensions of 85.6 x 54.0 x 5.0 millimeters. The dimensions conform with the specifications issued by the Personal Computer Memory Card International Association (PCMCIA) for a type II electronic card. The PCMCIA is an association that has promulgated a specification which list dimensions and other requirements for a standard electronic card. Each computer that conforms with the PCMCIA specification will contain slots that can receive a standardized card. With such a standard, electronic cards of one computer can be readily plugged into another computer, regardless of the model or make of the computers.

The PCMCIA standard includes three types of cards which each have varying thicknesses. A type I card is approximately 3.3 millimeters thick, a type II card is approximately 5.0 millimeters thick and a type III card is approximately 10.5 millimeters thick. The computer has a plurality of adjacent slots that are wide enough to receive a type II card. Both the type I and II cards occupy a single slot, while the type III card occupies two slots. Each computer slot contains a 68 pin connector that is typically mounted to a motherboard to provide an interconnect to the computer system. The connector 14 of the card assembly 10 has 68 pins that correspond to the pins of the host connector, so that the card can be plugged into the computer.

As shown in Figure 2, the card unit 10 contains a magnetic disk 16 which is rotated by a spin motor 18. The magnetic disk 16 rotates relative to an actuator arm assembly 20 which contains a head(s) 22 that can magnetize and sense the magnetic field of the disk 16. The actuator arm assembly 20 and spin Tiotor 18 are coupled to a printed circuit board 24 located at one end of the card assembly 10. The printed circuit board 24 supports a plurality of electrical components 26 that control the operation of the disk drive. The spin motor 18, actuator arm assembly 20 and printed circuit board 24 are mounted to a base plate 28 and enclosed by the cover plate 30 shown in Fig. 1.

As shown in Figure 3, the cover plate 30 is attached to the base plate 28 by a clamp 32. The clamp 32 is preferable constructed from a magnetic stainless steel for electromagnetic shielding and has a C shaped cross-section. The C shaped clamp 32 has a pair of leg portions 34 that extend from a base portion 36. The leg portions 34 engage outer flange portions 38 of the plates 28 and 30. The clamp 32 has a plurality of tabs 40 which extend into corresponding slots 42 in the plates 28 and 30. Both the tabs 40 and the slots 42 incline toward the edge of the card assembly to lock the clamp 32 onto the housing 12 and prevent ar.y inadvertent separation of the clamp 32 from the drive.

Figure 4 shows the clamp 32 in an unassembled condition. The leg portions 34 are relaxed and point inwardly of the clamp 32. The distance between the end of the leg portions 34 is less than the combined thickness of the outer flanges 38 of the plates. The clamp 32 is typically assembled onto the housing 12 by pushing the leg portions 34 onto the outer flange portions 34 until the tabs 40 lock into the slots 42. Pushing the clamp 32 onto the housing 12 deflects the leg portions 38 away from the outer flanges 38. The deflection of the stainless steel leg portions 34 create,counteracting spring forces on the housing to press the together the plates 28 and 30. The deflection and stiffness of the leg portions 34 is such that the plates 28 and 30 are rigidly fastened together. Figure 5 shows an alternate embodiment wherein the housing 12' has notches 44 that extend into slots 48 in the clamp 32 ' .

Referring to Fig. 3, located between the clamp 32 and the edges of the housing 12 is an elastomeric strip 48. The strip 48 extends along the length of the clamp 32 and is constructed to absorb any forces that are applied to the outer edges of the disk drive. The card assembly 10 is typically plugged into a computer housing which supports the disk drive along the outer edges of the card. Consequently any shock applied to the host computer is typically transmitted to the disk drive through the edges of the card. The force of the shock load will cause the clamp 32 to move relative to the housing 12. The frictional forces between the clamp 32 and housing 12 further dampen the load applied to the edges of the disk drive. The elastomeric strip 48 and sliding clamp 32 absorb the external forces and essentially isolate the card assembly from the computer housing, so that shock and vibration loads from the computer housing do not effect the operation of the drive. The elastomeric strip 48 and sliding clamp 32 will also absorb shock loads caused by other events such as a user dropping an unplugged card onto a hard surface.

The present invention thus provides a small profile fastening means for attaching a cover plate to the base plate of a hard disk drive that complies with the PCMCIA specifications. The clamp assembly also absorbs shock loads applied to the edges of the card. Additionally, the metallic clamp provides an EMI (electromagnetic interference) shield for the edges of the disk drive. The EMI shielding protects the internal components of the drive from magnetic fields er an v ce versa. e metallic clamp can also provide a means of ESD (Electrostatic discharge) when the card is plugged into the host computer. When a PCMCIA card type hard drive is plugged into a host computer, the card may have static electricity that is discharged to the host through the mating connectors. Such a discharge may introduce large voltage spikes to the host, which may damage the system particularly if the computer is operating during card insertion. The metal clamp of the present invention provides a conductive path between the card and the computer housing, so that any static electricity is discharged to the housing before the connectors are mated.

Figure 7 discloses an embodiment of the clamp wherein the elastomeric bumper is mounted to the housing of the disk drive. In this embodiment, the disk drive has a top elastomeric strip 60 that is mounted to a cover plate 62 and a bottom elastomeric strip 64 which is attached to a base plate 66. The strips 60 and 64 are encapsulated by a clamp 68.

As shown in Figure 8, each ^"strip 60 and 64 has a plurality of studs 70 that are inserted into corresponding notches 72 located about the periphery of the plates 62 and 66. The studs 70 can be merely pressed into the notches 72 and/or bonded to the outer εurface of the plates 62 and 66. The studs 70 and notches 72 provide a ready means of assembling and disassembling the strips 60 and 64 and accompanying clamp 68.

While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that this invention not be limited to the specific constructions and arrangements shown and described, since various other

10 ca ons may occur to those ordinarily skilled in the art.

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Claims

What is claimed is:

1. A hard disk drive, comprising; a media; rotation means for rotating said media; an actuator arm assembly operatively connected to said media; a base plate that supports said rotation means and said actuator arm assembly, said base plate having a plurality of base plate notches; a cover plate that cooperates with said base plate to enclose said media, said rotation means and said actuator arm assembly, said cover plate having a plurality of cover plate notches; a first elastomeric strip that has a plurality of first studs that extend into said cover plate notches to attach said first elastomeric strip to said cover plate; a second elastomeric strip that has a plurality of second studs that extend into said base plate notches to attach said second elastomeric strip to said base plate; and, a clamp that clamps said cover plate to said base plate and encapsulates said first and second elastomeric strips.

2. The hard disk drive as recited in claim 1, wherein said clamp has a C shaped cross-section that includes a first leg portion which applies a pressure to said base plate and a second leg portion that applies a pressure to said cover plate.

3. The hard disk drive as recited in claim 2, wherein said plates have a combined outer flange portion with a total thickness greater than a distance between said leg portions when said clamp is in an unassembled condition.

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4. The hard disk drive as recited in claim 1, wherein said clamp has tabs which extend into corresponding slots in said plates.

5. The hard disk drive as recited in claim 1, further comprising a connector located at one end of said plates.

6. The hard disk drive as recited in claim 1, wherein said plates have a combined thickness no greater than 5.0 millimeters.

7. The hard disk drive as recited in claim 1, wherein said clamp provides an electrical path between said plates.

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