1.8''PCMCIA COMPATIBLE DRIVE HAVING TWO OR MORE DISKS

Abstract: A portable pocket-size hard disk drive unit (10) that conforms with the PCMCIA type III format. The drive unit includes a housing (12) that contains a pair of magnetic disks (48, 50) that are coupled to a hub assembly. The hub assembly has a hub (52) which is rotated about a spindle shaft (54) by an electric motor (66) that is located within the hub. The hub assembly also has a pair of fluid bearings (96, 100) which have a small profile and are rugged enough to withstand the type of external loads that may be applied to a hand held portable disk drive unit. The magnetic disks rotate relative to a head/actuator assembly which is coupled to a connector (14) located on the end of the housing. The connector is adapted to mate with a connector in a computer system to couple the magnetic disks and disk drive assembly with the computer.

Description: 1.8" PCMCIA COMPATIBLE DRIVE HAVING TWO OR MORE DISKS BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION The present invention relates to a hard disk drive assembly. 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 allows 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 would be 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, such as by dropping the card onto a hard surface. The existence of such a card would also allow the user to accumulate memory in the same manner that floppy disk are used today. SUMMARY OF THE INVENTION The present invention is a portable pocket-size hard disk drive unit that conforms with the PCMCIA type III format. The drive unit includes a housing that coupled to a hub assembly. The hub assembly has a hub which is rotated about a spindle shaft by an electric motor that is located within the hub. The hub assembly also has a pair of fluid bearings which have a small profile and are rugged enough to withstand the type of external loads that may be applied to a hand held portable disk drive unit. The combination of the in-hub motor and fluid bearings provides a hub assembly which can fit within the PCMCIA type III format. The magnetic disks rotate relative to a head/actuator assembly which is coupled to a connector located on the end of the housing. The connector is adapted to mate with a corresponding connector in a computer system, to couple the magnetic disks and disk drive assembly with the computer. The hard disk drive assembly is approximately the size of a credit card, providing the user with a drive unit that can be easily stored and carried. Therefore it is an object of the present invention to provide a hard disk drive unit which can conform to the PCMCIA type III memory card format. BRIEF DESCRIPTION OF THE DRAWINGS 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 card unit of the present invention; Figure 2 is a cross-sectional view taken at line 2-2 of Fig. 1 ; Figure 3 is a cross-sectional view, showing the hub assembly of the card; Figure 4 is a top view of the card without the cover; Figure 5 is an enlarged view showing a spindle shaft attached to the cover of the card. DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings more particularly by reference numbers, Figures 1-5 shows a hard disk drive card unit 10 of the present invention that can be plugged into a computer 11. The unit 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 10.5 millimeters. The dimensions conform with the specifications issued by the Personal Computer Memory Card International Association (PCMCIA) for a type III electronic card. The PCMCIA is an association that has promulgated a specification which Hst 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 PCMCIA standards were originally established for memory and/or logic cards including internal modem and facsimile boards. The present invention provides a hard disk drive unit that can conform to the PCMCIA type III card format. In the preferred embodiment, the connector 14 of the card assembly 10 has 68 pins which can mate with the 68 pin connector located in the computer. The connector 14 is typically constructed from a dielectric material that has a plurality of pins or sockets as is known in the art. In the preferred embodiment, the connector 14 contains sockets which mate with pins located in the computer connector. As shown in Figs. 2 and 3, the housing 12 includes a first cover 16 and a second cover 18 both attached to a baseplate 20. The first cover 16 is typically attached to the baseplate 20 by an adhesive, the second cover 18 is typically attached to the baseplate 20 by a plurality of screws 22. In the preferred embodiment, the baseplate 20 includes four bosses 24, each containing a threaded hole 26 that receives a corresponding screw 22. The second cover 18 includes four counterbores 28 that contain the heads of the screws. The first 16 and second 18 covers are both preferably constructed from a hard plastic that is reinforced with a thin sheet of metal such as steel. In addition to increasing the stiffness of the covers, the steel protects the internal components from external electromagnetic interference and also prevents undesirable emissions from the card itself. As shown in Fig. 4, attached to the baseplate 20 are a pair of arms 30 that each have a pair of slots 32. The slots 32 capture ears 36 that extend from the connector 14. The arms 30 and ears 36 couple the connector 14 to the housing 12. As show in Fig. 2, the sockets of the connector 14 each have a pair of solder tails 38 that are solder to the surface pads of a printed wiring board (PWB) 40. The PWB 40 extends across the card unit and has a number of electronic packages 42 that typically contain integrated circuits. The integrated circuits contain logic and memory elements electrically operate the card unit 10. The PWB 40 contains a number of conductive lines that interconnect the packages and couple the integrated circuits to the connector 14. The PWB 40 is attached to the baseplate 20 by a pin 44 that is pressed into a hole 46 in the board 40. As shown in Figs. 2 and 3, the drive unit 10 includes a first magnetic disk 48 and a second magnetic disk 50 that are adapted to store information in a binary format. Although two disks are described and shown, it is to be understood that four disks can be used in a drive unit of the present invention. In the preferred embodiment, each magnetic disk is constructed to store up to 52.5 megabytes of information. Although two disk are shown, it is to be understood that the drive unit may have only one magnetic disk. The disk are attached to a hub 52 which is coupled to a spindle shaft 54. The spindle shaft 54 is secured to the baseplate 20 by a shaft portion 56 which is pressed into a bore 58 in the plate 20. The hub 52 includes an annular outer wall 62 that is attached to a radial bearing support 64 which has an annular inner wall that is adjacent to the spindle shaft 54. Within the hub 52 is an electric motor 66 which has a coil 68 wrapped around a magnetic core member 70. The hub also has an inner annular magnetic wall 72 to provide a return path for the magnetic flux of the electric motor 66. The electric motor 66 is supported by the baseplate 20 and a support ring 74. The electric motor 66 is coupled to the PWB 40 by a flexible circuit 76 and a connector 78 that plugs into the PWB 40. The electric motor 66 rotates the hub 52 and disk 48 and 50 relative to the spindle shaft 54. Placing the motor 66 within the hub 52 greatly reduces the thickness of the drive unit 10. The first disk 48 is supported by a bottom annular flange 80 of the hub 52 and is separated from the second disk 50 by an annular spacer 82. The outer wall 84 of the hub 52 has a pair of disk grooves 86 and a retainer groove 88 located adjacent to a top annular flange 90 of the hub 52. The top annular flange 90 and retainer groove 88 capture an elastic ring 92 which applies pressure to the second disk 50. The pressure of the elastic ring 92 is translated through the spacer 82 and pushes the first disk 48 onto the bottom hub flange 80. The ring 92 pressure secures the disk to the hub 52. The disk grooves contain O-rings 94 which compensate for tolerances in the parts and absorb external forces which may be applied to the drive unit. The elastomeric members 94 reduce the stresses on the motor assembly which may be caused by excessive external shock or vibrational loads. The O-rings are located relative to the disk to absorb loads in either a radial or axial direction relative to the hub 52. Coupling the disks to the hub 52 with the elastic ring 94 also reduces the profile of the assembly 10. In the preferred embodiment, the spindle shaft 54 includes a radial fluid bearing 96 that is adjacent to the inner walls of the radial bearing support 62. The radial fluid bearing 96 is typically filled with an oil through a port 98 located in a wall of the bearing. The fluid bearing 96 creates a thin layer of fluid between the spindle shaft 54 and radial bearing support 62 to decrease the friction therein. Adjacent to the radial bearing 96 is an axial fluid bearing 100 which is captured by the radial bearing 96 and a closing plate 102. The cover plate 102 is coupled to the radial bearing 96 by a screw 104. The axial plate bearing 100 has an annular slot 106 and a port 108 which are filled with oil. The oil creates a thin layer of fluid between the bearing 100 and the radial bearing support 62. The fluid bearings 96 and 100 provide a bearing assembly that has a small profile and is strong enough to withstand the shock loads typically applied to the card unit. In the preferred embodiment, the spindle shaft 54 is attached to the first cover 16. As shown in Figure 5, the shaft 54 may be coupled to the cover 16 by a sheet of soft metal 110 and a layer of a visceral elastomeric material 112. The top of the screw 104 may have protrusions which are embedded into the metal sheet 110, which is typically constructed from a soft aluminum. The elastomeric sheet 112 is typically bonded to the metal sheet and cover 16 by an adhesive. The elastomeric sheet 112 absorbs external loads, particular loads that induce shear between the spindle shaft 54 and the cover 16. The electric motor 66 rotates the magnetic disk relative to a head/actuator assembly 114. The head/actuator assembly 114 includes a plurality of magnetic heads 116 each attached to a corresponding flexure arm 118. In the preferred embodiment, there are four heads 116 each capable of magnetizing or sensing the magnetic field of an adjacent surface of the disk. The heads 116 are coupled to the integrated circuits by a flexible circuit (not shown) that plugs into a connector 120 mounted onto the PWB 40. The flexure arms 118 are attached to actuator arms 122 by a number of bosses 124. As shown in Fig. 4, the location of the bosses 124 are preferably off-center to decrease the profile of the overall assembly. The off-center location of the bosses 124 also allows each individual flexure arm 118 and accompanying magnetic head 116 to be replaced without having to remove the other bosses and arms. The actuator arms 124 extend from an actuator hub 126 that is coupled to an actuator spindle shaft 128 by a pair of roller bearings 130. The actuator shaft 128 has a base portion 132 that is pressed into an aperture 134 in the baseplate 20. The bearings 130 allow the actuator arms 122 to rotate relative to the shaft 128 and baseplate 20. Attached to the actuator hub 126 is an actuator coil 136 that is coupled to a magnet 138. The magnet 138 extends from a plate 140 that is mounted to the baseplate 20. Both the actuator coil 136 and magnet 138 are covered by a second plate 144 that is also bolted to the baseplate 20 by screws 146. The coil 136 is coupled to the electronic packages by a flexible circuit (not shown). The coil 136 and magnet 138 move the actuator arms 122 and heads 116 in accordance with signals provided from the electronic packages. In operation, the card unit 10 is plugged into an existing computer slot by mating the connector 14 with the connector in the computer. The computer provides power and digital signals to the electronic packages through the connector 14 and PWB 40. Power is supplied to the electric motor to rotate the disk relative to the head/actuator assembly. The heads write or read binary information onto, or from, the magnetic disks in accordance with instructions provided by the computer and the integrated circuits of the drive unit. The heads can move to a new location on the disk by providing a current to the actuator coil through the flexible cable. The drive unit can be coupled to another computer by merely pulling the card unit out of the existing slot and plugging the card into the new computer slot. The size and weight of the card assembly of the present invention also provides a disk drive unit which is easy to store and carry. 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 modifications may occur to those ordinarily skilled in the art.

Claims: What is claimed is: 1. A hard disk drive unit that can be plugged into a computer, comprising: a housing having an inner cavity; a spindle shaft coupled to said housing within said inner cavity; a hub adapted to rotate relative to said spindle shaft; a fluid bearing assembly that couples said hub to said spindle shaft; a first magnetic disk coupled to said hub; a first head/actuator arm assembly coupled to said first magnetic disk; connector means for coupling said first head/actuator arm assembly and said first magnetic disk to the computer; and, an electric motor adapted to rotate said first magnetic disk relative to said first head/actuator arm assembly. 2. The unit as recited in claim 1, further comprising a second magnetic disk coupled to said hub. 3. The unit as recited in claim 1, wherein said electric motor is located within said hub. 4. The unit as recited in claim 1, wherein said fluid bearing assembly includes a radial fluid bearing and an axial fluid bearing. 5. The unit as recited in claim 1, further comprising an elastic ring that is captured by a top flange extending from said hub, said elastic ring being adapted to couple said first magnetic disk to said hub. 6. The unit as recited in claim 5, further comprising a second magnetic disk that is separated from said first magnetic disk by a spacer. 7. The unit as recited in claim 1, wherein said housing is no greater than 10.5 millimeters thick. 8. The unit as recited in claim 1, wherein said housing includes a first cover coupled to a second cover. 9. A hard disk drive unit that can be plugged into a computer that has a first connector, comprising: a housing having an inner cavity; a second connector attached to said housing, said second connector being adapted to be mated with the first connector; a spindle shaft attached to said housing within said inner cavity; a hub adapted to rotate relative to said spindle shaft; a fluid bearing assembly that couples said hub to said spindle shaft; a first magnetic disk coupled to said hub; a first head/actuator arm assembly coupled to said first magnetic disk and operatively connected to said second connector; a second magnetic disk coupled to said hub; a second head/actuator arm assembly coupled to said second magnetic disk and operatively connected to said second connector; and, an electric motor located within said hub and adapted to rotate said hub and said magnetic disks relative to said head/actuator arm assemblies. 10. The unit as recited in claim 9, wherein said fluid bearing assembly includes a radial fluid bearing and an axial fluid bearing. 11. The unit as recited in claim 9, further comprising a spacer that separates said second magnetic disk from said first magnetic disk. 12. The unit as recited in claim 11, further comprising an elastic ring that is captured by a top flange extending from said hub, said elastic ring being adapted to couple said magnetic disks to said hub. 13. The unit as recited in claim 12, further comprising a pair of elastomeric members that are adjacent to said hub and said magnetic disks. 14. The unit as recited in claim 9, wherein said housing is no greater than 10.5 millimeters thick. 15. The unit as recited in claim 14, wherein said housing has dimensions of approximately 85 by 54 by 10 millimeters. 16. The unit as recited in claim 9, wherein said first and second magnetic disks are each approximately 45 millimeters in diameter. 17. The unit as recited in claim 9, wherein said first head/ actuator arm assembly has a first coupling boss and said second head/actuator arm assembly has a second coupling boss, said first coupling boss being separated from said second coupling boss in a plane perpendicular to a rotational axis of said hub. 18. A hard disk drive unit that can be plugged into a computer that has a first connector, comprising: a first cover; a second cover coupled to said first cover, said first and second covers forming an inner cavity; a second connector coupled to said first and second covers, said second connector being adapted to be mated with the first connector; a spindle shaft coupled to said second cover within said inner cavity, said spindle shaft having a radial fluid bearing; an axial fluid bearing adjacent to said radial fluid bearing; a hub coupled to said spindle shaft and adapted to rotate relative to said fluid bearings, said hub having top and bottom annular flanges; a first magnetic disk mounted to said bottom annular flange of said hub; a first head /actuator arm assembly coupled to said first magnetic disk and operatively connected to said second connector; a second magnetic disk coupled to said first magnetic disk; a second head/actuator arm assembly coupled to said second magnetic disk and operatively connected to said second connector; a spacer that separates said first magnetic disk from said second magnetic disk; an elastic ring captured by said top annular flange of said hub and adapted to press said first and second magnetic disks into operative contact with said bottom annular flange of said hub; and, an electric motor located within said hub and adapted to rotate said hub and said first and second magnetic disk relative to said first and second head/actuator arm assemblies. 19. The unit as recited in claim 18, wherein said first and second covers are no greater than 1.5 millimeters thick. 20. The unit as recited in claim 19, wherein said first and second covers have dimensions of approximately 85 by 54 by 10 millimeters. 21. The unit as recited in claim 20, wherein said first and second magnetic disks are each approximately 45 millimeters in diameter. 22. The unit as recited in claim 21, wherein said first head/actuator arm assembly has a first coupling boss and said second head/actuator assembly arm has a second coupling boss, said first coupling boss being separated from said second coupling boss in a plane perpendicular to a rotational axis of said hub. 23. A hard disk drive unit that can be plugged into a computer, comprising: a housing having an inner cavity, said housing having dimensions of approximately 85 by 54 by 10 millimeters; a first magnetic disk operatively connected to said housing within said inner cavity; a first head/actuator assembly arm operatively connected to said first magnetic disk; an electric motor adapted to rotate said first magnetic disk relative to said first head/actuator arm assembly; and, connector means for coupling said first head/actuator arm assembly and said first magnetic disk to the computer. 24. The unit as recited in claim 23, further comprising a second magnetic disk operatively connected to said housing, and a second head/actuator arm assembly coupled to said second magnetic disk and operatively connected said connector means. 25. The unit as recited in claim 24, wherein said connector means includes a 68 pin connector. 26. An apparatus, comprising; means for providing a hard disk drive unit which has the dimension of approximately 85 by 54 by 10 millimeters.

Inventors: CHESSMAN H ROSS, CUCCIO ALLEN, DION F EUGENE, KLERKS AUGUST L, CHESSMAN, H., ROSS, CUCCIO, ALLEN, DION, F., EUGENE, KLERKS, AUGUST, L.
Applicants: MAXTOR CORP, MAXTOR CORPORATION
Application year: 1993
Main classification: G11B17
IPC codes: G11B19, G11B25, G11B33