Adapter apparatus for use in connecting a printed circuit board to a computer chasis

A generally plate-shaped adapter device has an inner edge portion with spaced bosses thereon that may be snapped into tooling holes in a printed circuit board which is smaller than the circuit board originally designed to be secured to mounting portions formed on a computer chassis wall. The in-place adapter device forms an outward edgewise extension of the smaller circuit board and has an outer edge portion positioned and configured to cooperate with the chassis board mounting structure in a manner permitting the reduced size printed circuit board to be operatively mounted on the chassis wall without modification of its board mounting structure.

BACKGROUND OF THE INVENTION 
The present invention generally relates to the connection of printed 
circuit boards to associated chassis structures and, in a preferred 
embodiment thereof, more particularly relates to adapter apparatus for use 
in connecting a printed circuit board, such as a motherboard, to a 
computer chassis. 
Two of the most expensive parts in a personal computer are its enclosure, 
or chassis, and its main system printed circuit board which is commonly 
referred to as a "motherboard". The ability to utilize a number of 
motherboard designs in conjunction with a single chassis design is a 
manufacturing necessity due to the time and expense involved in designing 
and developing a new chassis. Three or four new motherboard designs can 
typically be made ready for market in the time it customarily takes to 
develop a new chassis design. 
Large cost savings can be achieved by decreasing the size of a motherboard 
even slightly. Due to the current rapid development in component 
miniaturization, increased chip function capabilities and manufacturing 
improvements that allow circuit board real estate to be more densely 
packed, opportunities for cost reductions from motherboard size decreases 
often arise several times during the production life of a given chassis 
design. 
In order to take advantage of the cost savings arising from a motherboard 
size reduction, it has heretofore been necessary to revise the 
configuration of the original chassis, for example by relocating board 
mounting bosses or board lock structures on the chassis, to accommodate 
the smaller motherboard. The requirement for this chassis modification, of 
course, can undesirably offset a substantial portion of the cost savings 
achieved in the motherboard size reduction. 
From the foregoing it can readily be seen that it would be highly desirable 
to provide apparatus and methods for permitting a single computer chassis 
to accommodate a reduction in the size of the motherboard that it was 
originally designed to operatively support without the necessity of 
altering the configuration of the chassis. It is accordingly an object of 
the present invention to provide such apparatus and methods. 
SUMMARY OF THE INVENTION 
In carrying out principles of the present invention, in accordance with a 
preferred embodiment thereof, a first printed circuit board, 
representatively a motherboard, is operatively secured to a computer 
chassis wall in place of second printed circuit board, larger in an 
edgewise direction than the first circuit board, using a specially 
designed extender device embodying principles of the present invention. 
The extender device representatively has a generally plate shaped 
configuration and is conveniently formed as a one piece plastic molding. 
First mounting means are provided for releasably holding the extender 
device on the first printed circuit board in a manner such that the 
extender device forms an edgewise extension of the first printed circuit 
board. Illustratively, the first printed circuit board has mounting holes 
formed therein adjacent side edge portions thereof, and the first mounting 
means include these mounting holes, boss portions formed on the extender 
device and removably receivable in the mounting holes, and resilient tab 
portions of the extender device providing for a snap-fit connection 
between the extender device and the first printed circuit board and 
configured to engage the first printed circuit board and releasably retain 
the boss portions in the mounting holes. 
Second mounting means are formed on the chassis wall and are configured to 
engage and operatively support on the chassis wall, in a parallel 
relationship therewith, the second printed circuit board which the 
foreshortened first printed circuit board replaces. With the extender 
device attached to the first printed circuit board, the thus enlarged 
first printed circuit board is attached to the chassis wall by operatively 
engaging the second mounting means with the extender device and the first 
printed circuit board in a manner operatively supporting the first printed 
circuit board on the chassis wall in a parallel relationship therewith. 
In one illustrated version thereof, the second mounting means include 
mounting hook projections disposed on the chassis wall and received in 
corresponding slots formed in the first printed circuit board, and a board 
lock structure formed on the chassis wall and having a depressible latch 
portion releasably engaging an outer edge portion of the extender device 
to preclude an edgewise movement of the first printed circuit board that 
would permit withdrawal of the hook projections from the board slots. 
In another illustrated version thereof, the second mounting means include 
mounting hook projections formed on the chassis wall and received in 
corresponding slots formed in the first printed circuit board, and a 
hollow cylindrical mounting boss formed on the chassis wall and secured to 
the extender device using a fastener member passing through the extender 
device and threaded into the mounting boss. 
According to another feature of the present invention, an outer edge 
portion of the extender device is formed as a finger scoop structure 
defined by side-by-side oppositely curved arcuate sections. This finger 
scoop structure provides a convenient handling portion of the extender 
device that may be manually grasped to manipulate the first printed 
circuit board during its connection to and disconnection from the chassis 
wall.

DETAILED DESCRIPTION 
Referring initially to FIGS. 1-3, the present invention provides a 
specially designed adapter apparatus, representatively in the form of a 
generally plate-shaped molded plastic extender device 10. In a manner 
subsequently described herein, the extender device 10 is used to 
operatively connect a motherboard or other printed circuit board 12 on the 
board mounting structure of a wall portion 14 of a computer chassis 16, in 
place of a larger circuit board originally designed to be mounted on the 
chassis wall 14, without the previous necessity of altering the 
configuration of the chassis wall to accommodate the mounting of the 
smaller circuit board 12 thereon. 
The reduced size circuit board 12 is representatively of an elongated 
rectangular configuration and has front and rear ends 18 and 20, opposite 
side edges 22 and 24, and top and bottom sides 26 and 28. For purposes of 
discussion, it will be assumed that the length of the circuit board 12 
(i.e., the distance between its opposite ends 18, 20) is shorter than the 
length of the circuit board that the board 12 replaces. Circular tooling 
holes 30, 32 are respectively formed through left and right front corner 
portions of the circuit board 12, and an opposed pair of mounting slots 
34, 36 are formed through the circuit board respectively adjacent its 
opposite side edges 22 and 24 rearwardly of the front board end 18. It 
should be understood that tooling holes 30, 32 may simply be mounting 
holes formed within the circuit board 12 for purposes of mounting the 
extender device 10. 
The extender device 10 has an elongated, generally triangular body portion 
38 having a straight rear or inner side edge 40, opposite end portions 42 
and 44, and a pair of oppositely sloping outer side edge portions 46 and 
48, and a mounting hole 50 inwardly adjacent the juncture of the side edge 
portions 46, 48. Mounting tabs 52, 54 are positioned on the left and right 
ends of the body 38, project rearwardly beyond the rear side edge 40 of 
the body, and are respectively offset in upward and downward directions 
relative to the balance of the body 38. 
Upwardly and downwardly projecting cylindrical connection bosses 30a, 32a 
are respectively formed on the portions of the tabs 52, 54 that project 
rearwardly beyond the body side edge 40, and the distance between the 
bosses 30a, 32a is identical to the distance between the circuit board 
tooling holes 30, 32. Also respectively positioned on the opposite ends of 
the body 38, inwardly of the tabs 52 and 54, are a pair of mounting tabs 
56 and 58 that respectively project downwardly and upwardly beyond the 
balance of the body 38 and project rearwardly beyond its inner side edge 
40. 
For purposes later described, a finger scoop structure 60 is molded onto 
the outer side edge of the extender device body 38 at the juncture of the 
oppositely sloping side edge portions 46 and 48. The finger scoop 
structure 60 comprises a side-to-side pair of oppositely curved portions 
62, 64 that concavely face in forward and rearward directions, 
respectively. 
As previously mentioned, the chassis wall 14 has formed thereon a board 
mounting structure which was originally configured to mount on the chassis 
16 a printed circuit board longer than the illustrated printed circuit 
board 12. As best illustrated in FIG. 3, this board mounting structure 
representatively includes a pair of upwardly projecting mounting hook 
members 34a, 36a and a board lock structure 66 having a resiliently 
depressible latching portion 68 projecting upwardly from a body portion 70 
of the lock structure. Both the hook members 34a, 36a and the lock 
structure 66 are of conventional configuration and operation. 
Referring now to FIG. 2, the extender device 10 is operatively attached to 
the front end of the reduced length printed circuit board 12 by upwardly 
deflecting the rear end of the extender device end tab 52, downwardly 
deflecting the rear end of the end tab 54, inserting the front corner 
portions of the circuit board 12 into the spaces between the tab pairs 52, 
56 and 54, 58, and then releasing the deflected tabs 52, 54 to permit the 
extender bosses 30a, 32a to respectively snap downwardly and upwardly into 
their associated circuit board tooling holes 30 and 32, thereby releasably 
locking the extender device 10 onto the front end of the printed circuit 
board 12 as illustrated in FIG. 2. 
The printed circuit board 12 is then operatively installed on the chassis 
wall 14 by grasping the finger scoop structure 60, positioning the board 
slots 34, 36 over the hooks 34a, 36a, moving the circuit board downwardly 
to cause the hooks 34a, 36a to respectively pass upwardly through their 
associated board slots 34, 36, and then pushing the extender device 10 
(and thus the circuit board 12) rearwardly to cause the board lock latch 
portion 68 to be depressed by the extender device 10 and then snap 
upwardly into releasable locking engagement with the finger scoop 
structure curved portion 62, as illustrated in FIG. 3, to thereby 
releasably lock the installed circuit board 12 on the existing mounting 
structure of the chassis wall 14. 
In this manner, by using the extender device 10, the foreshortened printed 
circuit board 12 may be operatively installed on the chassis 16 without 
modifying the chassis in any manner. This, of course, advantageously 
eliminates the necessity of redesigning the chassis 16 every time a design 
improvement in the circuit board permits it to be of a smaller, less 
expensive size. In this event it is only necessary to provide another 
inexpensive molded plastic extender device appropriately configured to 
adapt the foreshortened circuit board to the existing board mounting 
structure on the chassis. 
It should be noted that no tools are needed to secure the extender device 
10 to the circuit board 12, and the molded-in finger scoop structure 60 
provides a convenient place to hold the circuit board when installing it 
and removing it from the chassis 16. The finger scoop structure 60 could 
also provide additional EMI ground points for the circuit board by adding 
a simple metal strap or conductive paint to the scoop structure 60. 
As described above, the outer curved portion 62 of the finger scoop 
structure 60 forms an abutment surface for the latch portion 68 of the 
board lock structure 60 representatively shown in FIG. 3. However, the 
extender device 10 can be alternatively used in conjunction with 
conventional hollow cylindrical mounting boss portions of the chassis wall 
such as the boss 72 shown on the wall portion 14a of the chassis 16a shown 
in FIG. 3A and replacing the board lock structure 60 shown on the chassis 
wall 14 in FIG. 3. In this case, a mounting screw 74 is simply extended 
downwardly through the extender device mounting hole 50 and threaded into 
the boss 74 to releasably mount the extender device 10 and the 
foreshortened circuit board 12 on the chassis wall 14a. 
An alternate embodiment 10a of the previously described molded plastic 
extender device 10 is illustrated in FIG. 2A and includes a generally 
triangular base wall 38a having an upstanding flange portion 76 around its 
periphery. The flange portion 76 has an inner side or base section 76a, 
and a pair of oppositely sloped outer side sections 76b meeting at an apex 
portion 76c outwardly adjacent a mounting hole 50a formed through the base 
wall 38a. Laterally extending rearwardly from a bottom portion of the base 
flange section 76a is an elongated mounting flange 78 having a pair of 
upstanding cylindrical bosses 80 at its opposite ends. 
Bosses 80 are disposed inwardly of a pair of resilient, generally J-shaped 
tabs 82 formed on the outer ends of the flange section 76a. Free end 
portions of the tabs 82 extend rearwardly past the bosses 80 and have 
opposed locking projections 84 (only one of which is visible in FIG. 2A) 
on upper portions of their facing sides. To install the extender device 
10a on the circuit board 12, the tabs 82 are outwardly bent, as indicated 
by the double-ended arrows 86 in FIG. 2A, the bosses 80 are passed 
upwardly through the circuit board tooling holes 30 and 32, and the tabs 
82 are released to cause the locking projections 84 to snap back over the 
top side 26 of the circuit board 12, thereby releasably locking the 
modified extender device 10a to a peripheral portion of the foreshortened 
circuit board 12 is illustrated in FIG. 2A. 
The circuit board 12 may then be installed on the chassis wall 14 (as 
previously described in conjunction with FIG. 3) by causing the apex 
section 76c of the flange portion 76 to depress and then abut the latch 
portion 68 of the board lock structure 66, or installed on the chassis 
wall 14a (as previously described in conjunction with FIG. 3A) by 
extending the screw 74 downwardly through the extender device mounting 
hole 50a and threading the screw into the mounting boss 72. 
The foregoing detailed description is to be clearly understood as being 
given by way of illustration and example only, the spirit and scope of the 
present invention being limited solely by the appended claims.