Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1996-11-14
2001-06-05
Gandhi, Jayprakash N. (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S689000, C361S727000, C361S802000, C439S374000
Reexamination Certificate
active
06243270
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the assembly of a computer system and more particularly to a method and apparatus for attaching a printed circuit board to the chassis of a computer system.
BACKGROUND OF THE INVENTION
The primary parts of a basic, desktop computer system include a keyboard, a monitor, and a box that contains most of the electronic devices that make the computer system work. The box includes a chassis or frame that houses the electronic devices in a convenient form factor. Included in the chassis are electronic devices externally apparent to the computer system user such as a disk drive, CD-ROM drive, and various switches, knobs, sockets, and light indicators. Removing the cover that protects these electronic devices reveals many more key electronic devices including, for example, processors, memory units, clocking devices, interfaces, and peripheral components, all of which are electrically coupled together on printed circuit boards (PCBs). One of these PCBs, usually the PCB containing the central processing unit and main memory, is referred to as the motherboard.
FIG. 1A
is a top-down view of motherboard
11
inside chassis
15
in accordance with the prior art. Motherboard
11
is attached to the bottom of chassis
15
by screws
10
, and is coupled to socket
12
of riser
13
. The edge of motherboard
11
is contained within motherboard edge guide
14
.
FIG. 1B
is a side view of the structure of
FIG. 1A
along the length of motherboard
11
, showing how motherboard
11
is affixed to chassis
15
by screws
10
, socket
12
, and motherboard edge guide
14
. Motherboard
11
contains electronic devices and interconnect lines (not shown), many of which are disposed on the top side of the motherboard.
Motherboard
11
includes electrical contact regions disposed at the edge of the motherboard in the region inserted into socket
12
. Motherboard edge guide
14
serves to support the edge of motherboard
11
and to guide the motherboard into socket
12
, aligning the electrical contact regions on the edge of the motherboard with corresponding electrical contact regions inside the socket. In this manner, the proper electrical couplings between motherboard
11
and socket
12
are made.
As consumers demand increased computer system functionality in smaller form factors, more electronic devices need to be squeezed into the limited space of PCBs, including motherboard
11
. One drawback of the prior art system of
FIG. 1A
is that there is a significant area of “keep-out” regions on the motherboard. A keep-out region is a region on the PCB where electronic devices cannot be placed because of some mechanical obstruction. For example, screws
10
create keep-out regions in the vicinity of the screw heads, and motherboard edge guide
14
creates a keep-out region in the vicinity of the portion of the guide that overlaps motherboard
11
.
As consumers demand lower priced computer systems, it becomes desirable to promote computer system chassis designs that can accommodate PCBs, such as motherboards, from any number of different motherboard vendors. Promoting motherboard competition in this manner typically has the effect of lowering motherboard prices. Motherboards from different vendors, however, may be different sizes. Unfortunately, because the chassis design of the prior art structure of
FIG. 1A
fixes the distance between motherboard edge guide
14
and the back of chassis
15
, this chassis design is unable to accommodate motherboards of varying lengths.
As consumers and computer support personnel demand more easily serviceable computer systems, it becomes desirable to implement a computer chassis design that allows for easy access to the motherboard. Allowing for easy access to the motherboard makes it easier to access key electronic devices such as the processor and system memory so that, for example, a computer system user can quickly upgrade either of these components. Unfortunately, because the chassis design of the prior art structure of
FIG. 1A
affixes motherboard
11
to the bottom of chassis
15
using screws
10
, it is necessary to remove the PCBs and other electronic devices that may be placed above motherboard
11
inside the chassis before removing the screws. This makes it difficult to access and service the electronic components on the motherboard.
SUMMARY OF THE INVENTION
A method and apparatus is described for attaching a printed circuit board to a chassis in a computer system. The printed circuit board (PCB) comprises electronic devices electrically coupled together and disposed on a first side of the PCB. The PCB also includes a rail that is connected to the underside of the PCB. This rail is configured to cooperatively engage a rail guide connected to the chassis of the computer system such that the rail guide holds the rail and the PCB to the chassis, and the PCB and rail can slide with respect to the chassis.
Other features of the present invention will be apparent from the accompanying drawings and the detailed description that follows.
REFERENCES:
patent: 3760233 (1973-09-01), Warwick
patent: 4739452 (1988-04-01), Fukunaga
patent: 4896248 (1990-01-01), Zell et al.
patent: 5019948 (1991-05-01), Steketee et al.
patent: 5594621 (1997-01-01), Van Rumpt
patent: 406021671 (1994-01-01), None
Gandhi Jayprakash N.
Intel Corporation
Kaplan David J.
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