Abstract:
A method and apparatus are disclosed for restricting electrical connection to an electrical contact in a hard disk drive. A hard disk drive is provided which includes an electrical interface having a plurality of electrical contacts, and a restricting member. Access to at least one of the electrical contacts is restricted through the restricting member such that an electrical connection between the restricted contact and another electrical contact is avoided. The restricting member may be a shroud associated with the restricted electrical contact. The shroud includes an access passage which allows for an electrical connection between the restricted electrical contact and a contact on a self test rack. The shroud also prevents a shorting jumper from being placed on the restricted electrical contact, thus reducing the possibility of an inadvertent electrical connection between the restricted electrical contact and another electrical contact.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Priority is claimed from U.S. Provisional Patent Application Ser. No. 60/371,136 filed Apr. 8, 2002 entitled “Connector Restricted Pin Access” which is incorporated by reference herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention related to electrical connectors, and, more particularly, to a method and apparatus for restricting electrical connection to a contact in an electrical connector in a hard disk drive. 
     BACKGROUND OF THE INVENTION 
     As is well known in the art, hard disk drives are data storage devices that typically employ magnetic or optical media to store data. The media is traditionally one or more disks, which contain concentric tracks that are capable of storing data. The disk drive contains a read/write head for each disk surface, and the read/write head is positioned over a particular track in order to read and/or write data to the track. The disk drive positions the read/write head over the appropriate track using servo information which is contained in the tracks. Servo reading is done with one read/write head at a time, while servo writing may be done with multiple read/write heads simultaneously. Each data track contains servo information in multiple locations to aid in the positioning of the read/write heads when reading/writing customer data. 
     Conventionally, in the context of magnetic media, servo information is written to the storage media using a servo track writer. As will be understood, a servo track writer is an expensive piece of capital equipment. The servo track writer includes hardware which is able to finely position the read/write heads in the disk drive and write servo track information to the magnetic media. Even though a dedicated servo track writer writes servo information to multiple disk surfaces simultaneously, the process of servo track writing can be relatively time consuming, since the magnetic media typically contain many thousands of data tracks each of which contain servo information written in multiple locations. However, because of their expense, disk drive manufacturers rely on as few servo track writers as possible to operate a manufacturing facility. 
     As will be understood, in manufacturing operations it is highly desirable to reduce manufacturing times and capital expenditures, in order to reduce the total cost of the hard disk drive. In order to help reduce the amount of capital equipment required for disk drive manufacture, and to help reduce manufacturing time, some manufacturers have begun using the disk drive itself to write servo track information, without requiring, or reducing the use of a dedicated servo track writer. Such a process is referred to herein as a self servo write (SSW) operation. While SSW can help reduce the number of servo track writers required in a manufacturing operation, thereby reducing cost, problems can result. 
     For example, as mentioned above, it is common for disk drives to contain more than one magnetic disk, with many designs including four (4) disks, resulting in eight (8) surfaces which are capable of storing data. Thus, eight read/write heads are present in such a disk drive. Moreover, the power supply used to operate the read/write heads during normal operation is designed only to supply enough power for one read/write head to operate at any given time. This creates a power supply problem when performing SSW, as it is beneficial and preferable to operate all of the read/write heads simultaneously to write servo information on each surface simultaneously, in order to minimize the amount of time required for SSW. Furthermore, it is common to write servo information in partial data track steps, thus requiring multiple passes to completely write the servo information for a data track. Thus, performing such a SSW operation can take a significant amount of time if it is accomplished one disk surface at a time. One way to reduce the amount of time required for SSW operations is to provide the disk drive with a higher capacity power supply capable of supplying enough power to operate all of the read/write heads simultaneously. This supply could be internal to the disk drive, and be included on each drive that is shipped. However, the added power is only required in the factory during the SSW operation to write multiple surface servo information, and not during normal customer data operations. Thus, a larger on board power supply would add a significant amount of cost to the disk drive, ultimately increasing the cost of the disk drive for the customer. Thus, it would be beneficial to perform a SSW operation using more than one read/write head simultaneously in the factory, while still providing the hard disk drive with a power supply optimized for a customer&#39;s use to operate one read/write head at a time. 
     One method which may be used to perform SSW with more than one read/write head simultaneously is to provide the disk drive access to an external power supply, which remains in the factory and does not ship on each drive. The disk drive manufacturer may use the external supply to power multiple read/write heads during SSW operations. The smallest adequate power supply on-board the disk drive to read and write with only one head is delivered to the customer, allowing the customer to pay only for the capability they need. The cost savings to the customer results from a reduced bill of materials and the reduced use of factory capital equipment. However, a problem arises in such a situation related to access to the external power supply. More specifically, providing an access point for the external power supply to connect to the disk drive may result in an unintended electrical connection between adjacent contacts which, in turn, may cause significant damage to the disk drive. 
     Typically, when manufacturing a hard disk drive, the components of the disk drive are assembled into a casting, which results in two available surfaces which may be used to provide an external electrical connection, namely, the back edge and the top. Furthermore, during manufacture, it is generally beneficial to place disk drives in racks when doing testing and servo track writing operations, thus leaving the back edge as the most convenient surface to use as the electrical connection to the external power supply. The back edge of disk drives generally contain electrical connections, which are contained in an edge-to-edge connector or interface, commonly known as a three-in-one connector. Such a three-in-one connector is widely used and incorporates an advanced technology attachment (ATA) connector recommended standard. 
     One form of a three-in-one connector is illustrated in  FIG. 1 . The three-in-one connector  20  contains contacts in three different areas. The three-in-one connector  20  contains power contacts  24 , jumper contacts  28 , and logic contacts  32 . The power contacts  24  include contacts which connect to a power output from a power supply associated with the equipment in which the hard disk drive is installed, such as a personal computer. The jumper contacts  28  typically include contacts to components within the hard disk drive. A shorting jumper may be used to short two adjacent contacts together, and enable or disable certain features within the disk drive, such as master or slave operation. The logic contacts  32  include contacts which are operable to transmit data to and from the disk drive for storage and retrieval. The power contacts  24  and the logic contacts  32  have a standardized configuration, leaving the jumper contacts  28  as a logical location for the connection to the external power supply. The jumper contacts are defined and commonly used by manufactures to customize disk drive operation. However, since the jumper contacts  28  provide an electrical connection to components within the hard disk drive, if a contact for the external power supply is connected to another contact within the jumper contacts  28 , severe damage to the components of the disk drive may result. Thus, it would be beneficial to have a contact for providing necessary power for performing a SSW operation, while also protecting the disk drive from damage which may result from an unintentional electrical connection between the power contact and another contact. 
     While the above-description is directed toward disk drives, it will be understood by those of skill in the art that similar problems exist in other industries. For example, certain computer components, such as, for example, a component containing an electronic erasable programmable read only memory (EEPROM), may require a voltage or current to be applied during manufacture that is not required for normal device operation by a customer. Thus, the present invention has broader applicability than disk devices and could be used with, for example, a portable electronic device which may include an EEPROM which is programmed with the operating system for the device. The EEPROM is programmed using a programming voltage which is greater than the normal operating voltage for the device. Accordingly, it would be advantageous to have a contact for providing necessary power for programming the device, while also protecting the device from an unintentional electrical connection between the power contact and another contact, which may cause damage to the device. 
     Accordingly, it would be advantageous to have a hard disk drive capable of performing a SSW operation using more than one read/write head simultaneously. It would be beneficial for the manufacturer to simultaneously write servo information for two or more read/write heads (known as a stagger write), or all read/write heads simultaneously (known as a full bank write). It would also be advantageous for such a disk drive to have a power supply optimized for normal operation of the read/write heads that use one read/write head at a time, thus helping to reduce the cost of the disk drive. Furthermore, it would be advantageous for such a disk drive device such as an optical drive or portable electronic device to have an electrical contact for connection to a temporary external power supply which has a relatively small likelihood of inadvertent contact with other electrical contacts to minimize potential damage to the disk drive or other electrical component. 
     SUMMARY OF THE INVENTION 
     The present invention solves the aforementioned problems and meets the aforementioned, and other, needs. 
     In one embodiment, the invention provides a method and apparatus for restricting electrical connection to an electrical contact in a hard disk drive. The invention provides a hard disk drive which includes an electrical interface having a plurality of electrical contacts, and a restricting member. Access to at least one of the electrical contacts is restricted through the restricting member such that the possibility of an electrical connection between the restricted contact and another electrical contact is substantially reduced or avoided. 
     In one embodiment, the restricting member is a shroud associated with the restricted electrical contact. The shroud includes an access passage which allows for an electrical connection between the restricted electrical contact and a contact on a self test rack. The shroud also prevents, or at least minimizes the possibility of, a shorting jumper from being placed on the restricted electrical contact, thus reducing the possibility of an inadvertent electrical connection between the restricted electrical contact and another electrical contact. The shroud may be integrated into a connector plate associated with the electrical interface, or may be placed on the restricted electrical contact during manufacture. 
     A cap may also be placed over the electrical contact to serve as the restricting member. 
     Additional features and other embodiments of the present invention will become apparent from the following discussion, particularly when taken together with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustration of a prior art three-in-one connector for a hard disk drive; 
         FIG. 2  is an illustration of a portion of an electrical connecter for a disk drive for one embodiment of the present invention; 
         FIG. 3  is an illustration of an electrical connector having a restriction portion for one embodiment of the present invention; 
         FIG. 4  is a cross-sectional illustration of a SSW contact and an associated shroud for one embodiment of the present invention; 
         FIG. 5  is a cross-sectional illustration of the SSW contact of  FIG. 4  and an associated pogo pin contact for one embodiment of the present invention; 
         FIG. 6  is a cross-sectional illustration of a SSW contact and associated shroud for one embodiment of the present invention; 
         FIG. 7  is a cross-sectional illustration of the SSW contact of  FIG. 6  and an associated pogo pin contact for one embodiment of the present invention; 
         FIG. 8  is a cross-sectional illustration of a SSW contact for one embodiment of the present invention; 
         FIG. 9  is a cross-sectional illustration of the SSW contact of  FIG. 8  and an associated pogo pin contact for one embodiment of the present invention; 
         FIG. 10  is a cross-sectional illustration of a SSW contact and an associated shroud and cap for one embodiment of the present invention; and 
         FIG. 11  is a perspective illustration of a hard disk drive and a test rack slot for one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention provides an electrical connector for a disk drive which includes contacts for power, logic, and jumper connections.  FIG. 2  is an illustration a portion of a connector  100  of one embodiment of the present invention illustrating the power contacts  104 , and the jumper contacts  108 . Within the power contacts  104  there is a +12V contact  112 , a first ground contact  116 , a second ground contact  120 , and a +5V contact  124 . Within the jumper contacts  108 , there is a GPIO-1 contact  128 , a GPIO-2 contact  132 , a GPIO-11 contact  136 , a first GPIO-10 contact  140 , a second GPIO-10 contact  144 , a GPIO-0 contact  148 , a first ground contact  152 , a second ground contact  156 , and a self servo write (SSW) contact  160 . The SSW contact  160 , in this embodiment, provides a contact for a minus 5V supply for use while performing a self servo write operation, as discussed above, using more than a single read/write head within the disk drive. Other voltages are also possible, with minus 5V being the voltage for this embodiment. Providing the SSW contact  160  enables the disk drive to perform the self servo write operation during manufacture by, for example, placing the disk drive in a test rack with the test rack having contacts to provide minus 5V to the SSW contact  160 . In this embodiment, the self test rack also may have contacts to connect to the GPIO-1 contact  128  and the GPIO-2 contact  132 , which send and receive data related to the self servo write operation. In one embodiment, the GPIO-1 contact  128  operates to receive servo write information from the self test rack, and the GPIO-2 contact  132  operates to transmit servo write information to the self test rack. 
     As previously discussed, when placing a minus 5V contact in the jumper contacts, making an electrical connection between this minus 5V contact and another jumper contact may result in damage to the electrical components within the disk drive. Such damage may result in the drive no longer being functional. In order to help insure that contact is not made between the minus 5V contact and another jumper contact, a physical change is made to the disk drive. Such a physical change is illustrated, for one embodiment of the present invention, in  FIG. 3 . The disk drive connector, or interface,  100  of  FIG. 3  includes a molded in shroud  168 , which provides restricted access to the SSW contact  160 . While the embodiment of  FIG. 3  has a shroud which is molded into the plastic which surrounds the electrical interface, and acts as an insulation around the SSW contact  160 , other devices for restricting access to the SSW contact  160  may also be used which are not molded into the plastic, such as, for example, a bead which is placed onto the contact at the manufacturing facility. Such a bead may be held in place around the SSW contact  160  by mechanical interference (force fit), or an adhesive. The shroud  168  restricts access by preventing a customer from placing a shorting jumper across the SSW contact  160  which would electrically connect the SSW contact  160  with, for example, the GPIO-1 contact  128 . By restricting access to the SSW contact  160  in such a way, the chances are significantly reduced that any electrical contact between the SSW contact  160 , and any of the other contacts in the jumper contacts area  108  will be made. In addition to providing a physical restriction to the SSW contact  160 , the shroud  168  also provides a visual indication that the contact should not be connected to any other contacts. In one embodiment, the shroud  168  is a different color, thus providing additional visual indication that the SSW contact  160  should not be connected to another contact. 
     Referring now to  FIG. 4 , a cross-sectional illustration of a SSW contact  160  and associated shroud  168  for one embodiment is now discussed. In this embodiment, the shroud  168  is configured such that the SSW contact  160  extends beyond the end of the shroud  168  by a distance D. This extension of the SSW contact  160  enables a “pogo pin” contact from a test rack to contact the SSW contact  160  relatively easily. A pogo pin contact is a contact which is associated with the test rack, and contains a mechanism which allows the contact to telescope with respect to the test rack, such that when a disk drive is inserted into the test rack the pogo pin contact contacts the appropriate electrical contact on the disk drive and maintains pressure on the electrical contact during testing operations. As illustrated in  FIG. 4 , the end of the SSW contact  160  extends beyond the end of the shroud  168 , thus allowing a pogo pin to have a relatively flat or slightly concave surface which contacts the SSW contact  160 . Other pogo pin surfaces are possible, so long as a reliable contact may be made to the SSW contact  160 .  FIG. 5  illustrates a connection between a pogo pin  170 , and the SSW contact  160  of  FIG. 4 . 
     In another embodiment, illustrated in  FIG. 6 , a shroud  172  extends beyond the end of the SSW contact  160 . In this embodiment, the test rack would be configured with a pogo pin which is operable to extend into the opening in the shroud  172  and contact the SSW contact  160 .  FIG. 7  illustrates a connection between such a pogo pin  174  and the SSW contact  160 . This embodiment further reduces potential contact with the SSW contact  160  and other jumper contacts, although it requires tighter tolerances for the placement of the disk drive into the test rack to insure the pogo pin  174  from the test rack enters the opening in the shroud  172 . 
     In another embodiment, illustrated in  FIG. 8 , the SSW contact  160  is manufactured such that it extends only a short distance beyond the base plate  176  of the plastic connector  100 . This configuration is referred to as a “runt pin” configuration. In this embodiment, even though no shroud is utilized, the likelihood of contact between the SSW contact  160  and other contacts is reduced because a shorting jumper is not able to be placed on the SSW contact due to its reduced height. Thus, even if a shorting jumper was attempted to be placed on an adjacent contact to the runt pin SSW contact  160 , the reduced height of the runt pin minimizes the likelihood of an unintended contact between it and another contact. In this embodiment, as illustrated in  FIG. 9 , the pogo pin contact  178  in the test rack is configured such that it extends to contact the runt pin on the disk drive, enabling contact to be made between the pogo pin contact  178  and the SSW contact  160 . 
     In another embodiment, illustrated in  FIG. 10 , a cap  180  is also used to restrict access to the SSW contact  160 . In this embodiment, the cap  180  is placed over the shroud  168  to completely insulate the SSW contact  160 . The cap  180  may be held in place by mechanical interference (force fit), by an adhesive, or by thermal shrinking of the cap after it is placed over the shroud. Thus, the possibility of inadvertent contact to the SSW contact  160  is further reduced. In the embodiment illustrated in  FIG. 10 , the cap  180  is placed over the shroud  168 , however it will be understood that other configurations of a cap may be used, such as a cap which blocks any access to the SSW contact  160  through the shroud  168 , as well as a cap that is placed over the SSW contact  160  without a shroud  168  being present at all. 
     Referring now to  FIG. 11 , a perspective illustration of a test rack slot  200  with respect to a hard disk drive  204  is now described for one embodiment of the present invention. In this embodiment, a hard disk drive  204  is inserted into the test rack slot  200 . As will be understood, there are typically a relatively large number of test rack slots  200  in a test rack for a disk drive manufacturing facility, in order to simultaneously test a large number of disk drives  204 . Since the test racks hold many test rack slots  200 , it is convenient and practical to have electrical contacts between the test rack slot  200  and the hard disk drive  204  only at the rear of the hard disk drive  204 , at the 3-in-1 connector  208  for the disk drive  204 . This contact point allows multiple test rack slots  200 , and thus multiple hard disk drives  204 , to be stacked relative to one another in order to make efficient use of available space. The disk drives  204  may then be slid into and out of the test rack slots  200 . To facilitate the electrical connections to the electrical contacts in the 3-in-1 connector  208 , the test rack slot  200  contains a number of pogo pins  212 . As mentioned above, pogo pins  212  operate to contact the appropriate electrical contacts in the 3-in-1 connector  208  to the proper test fixture contact to perform testing operations, and SSW operations. The number of pogo pins  212  illustrated in  FIG. 11  is for the purposes of illustration only, and a test rack slot  200  may contain any number of pogo pins  212 , including more or fewer pogo pins  212  than are illustrated in  FIG. 118 . The test rack slot  200  is configured such that, when a disk drive  204  is aligned and fully inserted into the slot  200 , the pogo pins  212  contact the appropriate electrical contacts within the 3-in-1 connector  208 . The disk drive  204  has a connection for an external power supply for enabling SSW operations for more than one head on the disk drive  204 . Thus, in this embodiment, the disk drive  204  is inserted into the test rack slot  200  and SSW operations, as well as other diagnostic and testing operations, may be performed. 
     While the invention has been described in reference to a disk drive, it also has applicability to other electronic devices which may have additional or different power requirements during manufacturing than required for normal customer use. For example, a cellular telephone or personal digital assistant may have an operating system programmed into a programmable read only memory. When programming the programmable read only memory, a voltage higher than required for customer use may be beneficial for manufacturing efficiency. In such a situation, a connection as described herein may be utilized to help prevent inadvertent contact between incompatible electronic contacts. 
     The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. Although the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g. as may be within the skill and knowledge of those in the art, after understanding the present disclosure. For example, the invention is described above in relation to hard disk drives, although the invention is also applicable to any application in which an electrical contact may be required for manufacturing purposes, but which is not needed by the device at the customer for normal device operation. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.