One-piece electronic cage

An electronic cage for housing electronic components (circuit boards and power supplies) therein, wherein the cage includes a box-like component receiving area defined by a plurality of upstanding side walls and a floor member. Part of the floor member projects from the box-like receiving area to thus expose various electronic devices (e.g., modules, connectors) located on a common, large board which may be positioned within the cage. Significantly, the cage is of one-piece construction, preferably of injection molded structural foam.

TECHNICAL FIELD 
This invention relates to enclosure structures for containing and 
supporting various electronic components such as circuit boards and power 
supplies, and particularly those structures for use in information 
handling systems (computers). Such enclosures are also referred to in the 
computer art as electronic cages. 
BACKGROUND OF THE INVENTION 
Various electronic cage structures are known in the art, with examples 
defined in U.S. Pat. Nos. 3,231,785 and 4,984,133, and also described in 
International Business Machines Corporation Technical Disclosure Bulletins 
Vol. 27, No. 7B (Dec., 1984), pp., 4218-4221 and Vol. 31, No. 7, (Dec., 
1988), pp. 364-369. Typically, these structures are comprised of several 
individual pieces, usually metal (e.g., aluminum, stainless steel), formed 
to the desired configuration by known metal working techniques (e.g., 
stamping, casting, etc.). Assembly is thus necessary to join these pieces 
to form the final desired structure, such assembly often requiring even 
further elements (e.g., screws, nuts, bolts) to secure various pieces. 
Should additional strength be necessary at various locations in the 
structure (e.g., to provide component guide means, added structural 
support for facilitation of cage securement to an associate frame, etc.), 
additional reinforcement elements are typically added for this purpose. 
The result is a finished structure, which, understandably, is relatively 
heavy as well as relatively time-consuming and otherwise expensive to 
produce. Because several individual elements are required, tolerance 
control has also been somewhat difficult to maintain, which control is 
particularly important in such structures (e.g., for aligning various 
internal components). Such structures have heretofore also typically been 
relatively difficult to access the internal areas thereof (e.g., in the 
event of repair) due primarily to the need for time-consuming disassembly 
operations. 
It is believed, therefore, that an electronic cage which overcomes the 
various disadvantages associated with cages such as described above would 
constitute a significant advancement in the art. 
DISCLOSURE OF THE INVENTION 
It is a primary object of this invention to enhance the art of electronic 
cages and particularly of those for use in the computer field. 
It is a more particular object of this invention to provide an electronic 
cage which is both strong and lightweight, yet which can be produced at 
relatively less cost in both time and material, than typical cages of the 
prior art. 
It is a still further object of the invention to provide such an electronic 
cage which provides for relative freedom of access to selected portions 
thereof, as well as for relative ease of removal of the various components 
(e.g., circuit boards, power supplies, etc.) supported and contained 
therein. 
It is yet another object of this invention to provide an electronic cage 
possessing the above advantageous features and which, significantly, is of 
one-piece, lightweight construction, thereby further assuring relatively 
tight tolerance controls in the finished product. 
In accordance with one aspect of the invention, there is provided an 
electronic cage comprising a floor member including first and second 
substantially adjacent portions, the floor member adapted for having a 
first circuit board positioned on both first and second portions thereof, 
and a plurality of side walls extending substantially upwardly from the 
first portion of said floor member, the first portion and side walls 
defining a substantially box-like electronic component receiving area for 
receiving and housing at least one second circuit board therein. The 
second portion of the floor member is substantially planar and projects 
outwardly from said substantially box-like receiving area such that the 
part of the first circuit board positioned thereon is substantially 
readily accessible. The electronic cage is of one-piece construction, to 
thus assure a lightweight end product having close tolerance control.

BEST MODE FOR CARRYING OUT THE INVENTION 
For a better understanding of the present invention together with other and 
further objects, advantages and capabilities thereof, reference is made to 
the following disclosure and appended claims in connection with the 
above-described drawing. 
In FIG. 1, there is shown an electronic cage 10 in accordance with a 
preferred embodiment of the invention. Cage 10 comprises a floor member 11 
which, as shown, extends substantially across the entire bottom portion of 
cage 10. As further defined herein, floor member 11 includes a first 
portion 13 and a substantially adjacent second portion 15. In a preferred 
embodiment, floor member 11 is substantially planar, with both portions 
being contiguous. 
Cage 10 further includes a plurality (e.g., four) of side walls 17, 18, 19 
and 20 which, as shown in FIG. 1, combine with the substantially solid 
second portion 13 of floor member 11 to define a substantially box-like 
electronic component receiving area 21 for receiving and housing at least 
one, and preferably several, individual electronic components therein. 
By the term electronic component as used herein is meant to include known 
circuit board structures (a/k/a printed circuit boards or printed wiring 
boards), including those having various electronic devices (e.g., modules, 
connectors, etc.) located thereon. Examples of such circuit board 
structures are illustrated in U.S. Pat. Nos. 4,131,933 (R. Agard et al) 
and 4,864,458 (G. Demorat, Jr. et al), both assigned to the same assignee 
as the present invention. These patents are incorporated herein by 
reference. Typically, such structures include a planar circuit board of 
substantially rectangular configuration and include such electronic 
devices on at least one surface thereof. Attention is directed to FIG. 2, 
wherein such a circuit board 23, including a plurality of electronic 
devices 25 thereon, is shown about to be positioned within cage 10. Such 
circuit boards as adapted for being positioned within cage 10 may further 
include additional structure (e.g., to prevent electrostatic discharge, as 
in U.S. Pat. No. 4,864,458, to provide reinforcement, etc.). The term 
electronic component is also meant to include power supplies or similar 
structures, which may also be positioned with electronic cages. One 
example is represented by the numeral 27 and shown in FIGS. 2 and 3. Power 
supplies are well known in the art and further description not believed 
necessary. 
By the term electronic devices as used herein is meant to include various 
electrical structures which may be positioned on circuit boards, 
particularly including modules, connectors, etc. By the term module as 
used herein is meant to define a packaged functional hardware unit 
designed for use with other electronic devices, such modules also referred 
to as logic and memory modules. Examples of such structures are described 
in U.S. Pat. Nos. 4,514,752 (P. Engel et al) and 4,962,416 (A. Jones et 
al), both assigned to the same assignee as the present invention. Both of 
these patents are incorporated herein by reference. It is understood that 
a variety of electronic devices, including modules of the type cited 
above, may be included on the circuit boards for being positioned within 
the present invention. Understandably, power supplies as mentioned above 
and shown are typically of substantially larger construction than the 
aforementioned modules and, as stated, are capable of being individually 
positioned within cage 10. The power supply 27 depicted in FIG. 2 is of 
substantially box-like configuration and includes various electronic 
device (e.g., modules) as part thereof, as is typical of power supplies of 
the current art. Such a power supply may also include at least one circuit 
board therein, this board having such devices mounted thereon. It is thus 
understood that the substantially box-like electronic component receiving 
area 21 of cage 10 is also specifically designed for having individual 
electronic components, such as power supply 27, positioned and retained 
therein. 
As further seen in FIG. 1, the first portion 15 of floor member 11 projects 
outwardly from the box-like component receiving area 21 defined by walls 
17-20 and first portion 13. This is considered a significant feature of 
the invention for reasons further explained below. 
As shown in FIG. 1, the outwardly projecting planar second portion 15 of 
floor 11 is substantially perpendicular to the upstanding side wall 20, 
which wall lies along the interface between portions 13 and 15. All of the 
walls 17-20 are also substantially perpendicular to the first portion 13. 
In a preferred embodiment, the opposed walls 17 and 18 are parallel and, 
as further defined below, include a plurality of openings 31 therein for 
permitting cooling (e.g., by air passage) to the cage's internally 
contained components. Further, the opposed pair of side walls 19 and 20 
are also preferably parallel and, significantly, of substantially solid 
configuration (not including cooling openings or the like. Of such 
substantially solid side walls, side wall 20 is deemed particularly 
significant with regard to the present invention. This solid side wall, as 
located, serves to substantially reinforce the overall cage structure at 
this location while further substantially preventing side wall "rotation" 
when the cage is positioned within the desired housing assembly designed 
to accommodate same. This is especially true when cage 10 is located on 
its side (e.g., on side wall 17 or 18, as defined further below). Examples 
of such assemblies may include what are referred to in the art as 
intermediate processor units, several types of which are manufactured and 
sold by the assignee of the present invention. Typically, such processor 
units may include more than one cage assembly as part thereof. 
In FIG. 2, cage 10 is shown about to receive the aforementioned circuit 
board 23 and adjacent power supply 27 within the box-like component 
receiving area 21 thereof. Prior to positioning of these members, however, 
cage 10 is designed to receive therein yet another circuit board, 
referenced by the numeral 33. This circuit board 33, like board 23, also 
includes a plurality of electronic devices such as modules and connectors 
25'. Board 33, as shown, is preferably substantially larger than the 
individual boards 23 and, like boards 23, also preferably of planar 
configuration. Board 33 further includes a plurality of receiving 
connectors 27, each designed for receiving a respective one of boards 23 
therein for providing electrical connection between boards 23 and the 
common (or mother) board 33. Such a board 33-board 23 relationship may 
also be referred to as a mother-daughter arrangement. Significantly, the 
larger board 33 is capable of being slidably positioned within the lower 
portion of cage 10 so as to be located on both first and second adjacent 
portions 13 and 15. This is accomplished by providing an elongated slot 35 
within the lower portion of solid side wall 20. The various electronic 
devices (e.g., connectors 27) on the portion of board 33 finally 
positioned on first portion 13 are of such height so as to enable such 
slidable positioning. Once fully positioned as depicted in FIG. 3, the 
part of board 33 including the aforementioned electronic devices 25', is 
positioned on the floor member's second portion 15 and thus so extends 
from the box-like receiving area 21. Significantly, this arrangement 
provides for ready access to such components 25' to enable repair and/or 
replacement thereof in a facile manner. 
In one embodiment of the invention, the modules which form components 25' 
were logic modules, these modules positioned on the exposed part of board 
33 by known attachment techniques. The connectors which form these 
components may also be attached using known techniques. When board 33 is 
fully inserted within cage 10, some means of retention is used to fixedly 
position the board in place. A preferred means for accomplishing this is 
to utilize a plurality of retention plugs 41 (FIG. 1) which may be 
positioned on floor member 11 at designated locations for being inserted 
within respective receiving holes (apertures) 43 within board 33. In one 
example, a total of seven such plugs 41 were utilized. Plugs 41 may also 
be inserted from beneath the floor member 11 and pass through provided 
apertures 45 within the floor at designated locations. Such apertures 45 
would in turn align with apertures 43 in board 33 and the individual plugs 
each inserted through aligned pairs thereof so as to effect board 
retention. Such a fit between plug and board would, understandably, be 
frictional in nature. 
Once board 33 has been fully positioned and secured within cage 10, the 
various circuit boards 23 and power supply 27 may then be positioned 
within component receiving area 21. To facilitate such positioning, the 
opposed pair of side walls 17 and 18 further include guide means 51 in the 
form of upstanding parallel walls 52 therein. Understandably, a pair of 
such parallel walls 52, defining an elongated channel therebetween, is 
designed for receiving a respective edge portion of a respective one of 
the incoming circuit boards 23. Thus, each board is slidably engaged at 
opposing edge portions thereof to guide the board such that connection is 
made to the larger board 33. In one example of the invention, cage 10 
received a total of eight individual circuit boards 23, thus providing a 
total of eight pairs of parallel walls within each side wall 17 and 18 for 
guiding these circuit boards into position. Because some walls provide 
common functioning in this regard (serve as a common wall in two adjacent 
pairs), a total of nine such walls 52 are required in each side wall, 
minimally, to receive a total of eight boards. 
For receiving the power supply 27, at least one (and preferably two) of the 
opposed side walls includes a partition 53 extending therefrom. As better 
seen in FIG. 1, two such partitions 53 are provided, each partially 
extending within the open receiving area 21. These two partitions 53 and 
parallel side wall 20 thus define an individual electronic component 
receiving area within the larger area 21, for power supply 27. As shown in 
FIG. 1, such an area is in the form of an elongated slot or the like for 
receiving the substantially box-like power supply 27. The solid side wall 
20 further includes a pair of latch members 55 spacedly located therein, 
each designed for being positioned within a corresponding opening 57 
provided within the outer casing of power supply 27. It is thus seen that 
integral latch members 55, which form part of the substantially solid side 
wall 20, thus serve to "capture" the power supply 27 and thereby securedly 
retain this component within cage 10. 
In accordance with the teachings herein, cage 10, including the 
aforementioned floor, side wall, partition, guide structure (walls 51) and 
latch members are, significantly, formed as a one-piece component. In a 
preferred embodiment, cage 10 is produced by injection molding, and of a 
material referred to as structural foam. Such material is capable of being 
successfully injection molded and provides sufficient structural integrity 
and strength to effectively contain the various electronic components 
described herein within the confines thereof. In a preferred example, cage 
10 was made from a polyphenylene oxide resin type of structural foam, one 
example being Noryl FM3020, available from the General Electric Company, 
Pittsfield, Massachusetts. (Noryl is a trademark of General Electric 
Company.) This structural foam material further includes approximately 30 
percent by weight glass reinforcement, a tensile strength (yield) of about 
10,500 pounds per square inch (psi), flexural strenqth (Yield) of about 
15,200 psi and a solid specific gravity of about 1.32 (in comparison to a 
foam specific gravity of 1.19). As stated, cage 10 is preferably produced 
by injection molding. To attain the structure of the material described 
herein, the injection mold is filled with the polyphenylene oxide resin 
and the appropriate percentage of glass fibers added thereto. 
Additionally, an inert gas (e.g., nitrogen) is added to give desired 
porosity to the final product. The result is a finished structure with, 
significantly, substantially solid outer portions and porous internal 
portions The resulting structure is lightweight and strong. Of further 
significance, the structure, being molded and thus of one-piece 
construction, provides for extremely tight tolerancing between the various 
surfaces of the structure. 
It is understood that plastic material other than that mentioned above 
(Noryl FM3020) may be successfully utilized in the present invention. The 
invention is thus not limited to this particular material. 
Utilization of an integral, injection molded cage assures other advantages, 
in addition to those above. For example, it is possible in such a 
structure to provide added reinforcement to designated locations therein 
(e.g., receiving area 21) without adding significant weight to the overall 
structure. Such additional weight is typically required in multi-piece 
(e.g., stainless steel) structures of the prior art. Such a strong 
structure also enables positioning of cage 10, including its internal 
components, in a position other than substantially horizontal, as is 
typical in prior art cage assemblies. Specifically, the invention as 
taught herein is capable of being readily positioned on its side such that 
one of the side walls (e.g., side wall 18) may rest upon a suitable 
horizontal ledge or the like within the designated processor unit. In such 
an arrangement, the opposed solid side walls 19 and 20 would thus be 
oriented substantially vertically within the processor. This is unlike 
many other cage orientations wherein the internal large circuit board 
(a/k/a planar) and the associated lower portion of the cage are oriented 
substantially horizontally. Understandably, in the side orientation 
described above, the larger board 33 will also assume a substantially 
vertical position within the designated processor unit. 
As stated, cage 10 is relatively lightweight. In various examples of the 
invention, cage 10 (excluding the various electronic components positioned 
therein) may possess a weight of within the range of only from about two 
to about six pounds. In one particular example, the plastic cage had a 
weight of only about 3.9 pounds. This cage thus weighs substantially less 
than typical metallic, multi-piece cage structures of the prior art, which 
usually weigh from about eight to about twelve pounds. Such a reduction in 
weight is, understandably, considered substantial. In the above example 
(wherein cage 10 weighed 3.9 pounds), the cage processed external 
dimensions of about 14 inches (length) by 14 inches (width), with a height 
of only about 5 inches. 
In FIGS. 1-4, there is shown a separate cover member 61 which may be 
utilized with the one-piece cage 10 to provide a cover for the circuit 
board members and other electronic components positioned within the cage's 
receiving area 21. Cover 61, as stated, is a separate structure and 
preferably of plastic material, a suitable example being a polycarbonate 
plastic including a carbon filler additive (to render the cover static 
dissipative). Cover member 61, as best seen in FIG. 1, is designed for 
being pivotally positioned on one of the upstanding side walls (19), with 
one side thereof including a pair of apertures 63 (FIG. 4) therein. A 
corresponding pair of projecting latch segments 65 also integrally formed 
as part of cage 10, are designed for aligning with and being positioned 
within the respective apertures 63 such that the separate cover 61 may 
pivot thereabout. Retention of cover 61, in the closed position, is 
assured through a pair of latch elements 67 which, like latch member 55, 
form an integral portion of cage 21 and are located on opposing sides 17 
and 18 in the area designed for accommodating the power supply 27. When 
cover 61 is fully closed, respective aperture tabs 69 thereon align with 
and engage the corresponding pair of latch segments 67 to retain the cover 
in a closed position. Cover 61, being plastic, is also extremely 
lightweight and, in one example of the invention, possessed a total weight 
of only about 4.5 pounds. 
Although only one aperture 63 is illustrated in FIG. 4, it is understood 
that another aperture, of similar configuration, is spacedly positioned 
along the same edge of cover 61 to accommodate the spaced second latch 
member 65. Both such latch members 65, as mentioned, are shown in FIGS. 1 
and 2 of the drawings and the second aperture 63 is thus understood to be 
located relative to the second of these. 
In FIG. 5, there is shown an enlarged view of a means for securing cage 10 
to the frame or similar structure of the electrical assembly (e.g., 
processor unit) into which cage 10 is to be positioned. In one embodiment 
of the invention, a pair of projecting flange members 71 are provided at 
the outer portion of second portion 15 of floor 11. See particularly FIGS. 
1-3. Each flange 71 is designed for aligning with a respective frame 
member 73 or the like of the corresponding processor unit. The protruding 
flanges 71 may be secured to each respective frame member using a screw 75 
or the like, as shown in FIGS. 3 and 5. Each flange 71 includes an opening 
77 (FIG. 1) therein to accommodate such a screw. Significantly, it has 
been determined that attachment of cage 10 to such a frame structure can 
be successfully accomplished utilizing only the described pair of flange 
members and associated screws or the like for attaching same as indicated. 
As mentioned above, the cage may be positioned within the processor frame 
by placement of the larger, box-like electronic component-receiving 
portion thereof atop a ledge or similar surface designed to accommodate 
same. Once so positioned, the respective flanges 71 are then secured to 
the processor's frame members. It is thus understood that securement as 
well as removal of cage 10 can be relatively easily accomplished. 
Thus there has been shown and described an electronic cage which is of 
relatively lightweight construction, yet which is sufficiently strong and 
rigid so as to include several circuit board assemblies and other related 
electrical components therein in a positive manner. The cage as defined 
herein also provides positive means for guiding such circuit boards and 
other components therein, while even further providing means for engaging 
and locking with associated structure (e.g., a cover). Significantly, the 
cage as described herein provides a readily accessible front part wherein 
various components located on a large circuit board or the like positioned 
within the cage are in turn readily accessible (e.g., for repair and/or 
replacement). 
While there have been shown and described what are at present considered 
the preferred embodiments of the invention, it will be obvious to those 
skilled in the art that various changes and modifications may be made 
therein without departing from the scope of the invention as defined by 
the appended claims.