Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1998-12-24
2001-02-06
Gandhi, Jayprakash N. (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S756000, C361S801000, C361S802000, C439S259000, C439S260000
Reexamination Certificate
active
06185104
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to methods and apparatus for removing and installing printed circuit boards from/into computer systems and the like and, more particularly, to methods and apparatus of this kind in which the printed circuit boards are extracted and installed laterally from a multi-card chassis without the need to disassemble the system, disturb other cards, or disrupt electrical power from being applied to the chassis.
Personal computers (PCs), PC servers, UNIX servers, and other computer systems typically incorporate chassis that carry a number of printed circuit boards, including input/output (I/O) cards, in connectors arranged in spaced, parallel relationship on a mother board or other support structure. Computer systems of this kind typically incorporate printed circuit boards or cards that are compatible with the standardized Peripheral Component Interconnect (PCI) bus. PCI cards have variable heights and widths, but all have a multiple-contact connector along their lower edges and a bulkhead mounted along an adjacent side edge.
Computer systems of the kind described above typically must be powered down while a faulty PCI card is being removed and replaced. In addition, in many instances, more than just a single card must be removed, because a small-outline card might be located adjacent to one or more full-size cards and thus be inaccessible. This card replacement procedure has proven to be lengthy and disruptive, and it has given rise to the need for a means that allows such cards to be removed and replaced without having to shut down electrical power to the remainder of the system. This is referred to as On-Line Replacement (OLR).
A fully capable OLR system includes OLR hardware, system software and OS support, device drivers, and a user interface. The hardware and software function together to ensure that any OLR activity is benign to other devices connected to the PCI bus. Typically, the PCI OLR hardware isolates the logic and the power signals of a single PCI slot from all other devices connected to the PCI bus. A digital OLR controller arbitrates for the PCI bus and controls all of the logic signals for each slot. Power control electronics allows for power sequencing on the PCI bus, ensuring that power to the card slot is switched off for on-line replacement, while stable power continues to be delivered to other devices on the PCI bus.
OLR solutions have been provided in the past by systems compatible with other industry standards, including VME or Compact-PCI cards, which are of a fixed size, or at most two fixed sizes. In these other systems, the cards are configured to be supported by card guides such that they can be removed and installed without contacting neighboring cards. Typically, the bulkheads of such cards are oriented orthogonal to the direction of extraction, and they incorporate handles and latches, for convenient replacement.
In contrast with the cards of such other industry standards, standard PCI cards are not of a fixed size, but instead have upper and rearward side edges with widely variable positions. In addition, the bulkhead of a PCI card is in line with the normal direction of extraction and is free of handles or other detail for facilitating its extraction. The force required to insert a 64-bit PCI card into a standard connector can be as high as 60 pounds.
Some OLR systems have been devised for use with PCI cards, but they are not considered to be entirely satisfactory. For example, one such system incorporates special adapters and handles, while another incorporates special dividers and guides, along with handles for accommodating size variations and obviating potential electrical shorting of adjacent cards. These known OLR systems for use with PCI cards use standard connectors and maintain a standard extraction procedure, in line with the bulkhead. This generally requires a removal of covers and/or drawers to gain access to the card cage.
It should therefore be appreciated that there is a need for an improved OLR system for use with PCI cards and the like, which facilitates a safe and convenient removal and replacement of the cards in a lateral direction and without requiring a shutdown of electrical power to any other cards. The present invention fulfills this need.
SUMMARY OF THE INVENTION
The present invention is embodied in an improved on-line replacement apparatus for removing and installing a printed circuit card from and into a computer system, laterally through a side wall, while other components of the system remain powered and operational. The printed circuit card has a lower edge, an upper edge, and a side edge, with a multiple-contact connector located along its lower edge and a bulkhead located along its side edge. The apparatus includes a chassis connector mounted on the chassis and having a plurality of electrical contacts that define a slot for receiving the lower edge of the printed circuit card. These chassis connector contacts are movable between a retracted position, in which the lower edge of the printed circuit card can be slid along the slot for removal and installation, and an engagement position, in which the chassis connector contacts make electrical contact with the card's multiple-contact connector and secure the card in place. The apparatus further includes a control lever for selectively moving the chassis connector contacts between their retracted and engagement positions, and a mechanical interlock for preventing the control lever from moving those contacts from their retracted position to their engagement position unless the printed circuit card has been fully inserted.
In more detailed features of the invention, the control lever includes an elongated rod mounted for rotation adjacent to the chassis connector contacts, and this rod is configured such that rotation of the rod about its longitudinal axis moves the chassis connector contacts between their retracted and engagement positions. The elongated rod preferably incorporates a section with a uniform, substantially oval cross-section, configured to engage the chassis connector contacts. In addition, the mechanical interlock preferably includes a block mounted on the chassis, adjacent to the chassis connector, and movable between a forward position and a retracted position, and it further includes a spring that biases the block to its forward position. Installing the printed circuit card into its prescribed installation position automatically moves the block to its retracted position, against the yielding bias of the spring. The mechanical interlock is configured to prevent the control lever from moving the chassis connector contacts to their engagement position while the block is in its forward position.
In a separate and independent feature of the invention, the apparatus includes a centering device, operable when the printed circuit card has been fully inserted into the chassis connector, for adjustably positioning the card such that its contacts are aligned with the corresponding chassis connector contacts. This centering device can include a spring-biased pin configured to engage and to center a key slot formed in the lower edge of the printed circuit card. The pin preferably is biased substantially orthogonal to the axis of the chassis connector slot; and it incorporates a conical section configured to engage the key slot of the printed circuit card and thereby adjustably position the printed circuit card in a prescribed installation position.
In yet another feature of the invention, the apparatus further includes an elongated card guide pivotally mounted on the computer system's side wall and biased, e.g., by a spring, toward the chassis. The card guide incorporates a slot configured to engage and retain the upper edge of a printed circuit card of varying height. This prevents the card from tilting toward an adjacent card, which could inadvertently short out electrical components on that adjacent card.
Other features and advantages of the present invention should be apparent from the followi
Dinh Tuan
Gandhi Jayprakash N.
Hewlett--Packard Company
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