Apparatus for the mounting and wiring of printed circuit boards

An apparatus adapted for the mounting and wiring of printed circuit boards includes front and rear supports which together define paired slots into which the circuit boards are receivable and thus transversely mountable relative thereto so as to maintain the boards in a substantially parallel, spaced apart relationship to one another. The boards can be securely locked in the mounted positions by a resilient ring or like structures which seats in a circumferential slot defined in the front and rear supports. An end bell housing is also disclosed whereby various electrical components can be assembled with the circuit boards by virtue of the locking engagement established with the rear support when the bell housing is rotated (e.g. as in a 1/4 turn) relative the rear support.

BACKGROUND AND SUMMARY OF THE PRESENT INVENTION 
1. Introduction 
In my copending U.S. application Ser. No. 427,277 entitled "Apparatus for 
the Mounting and Wiring of Printed Circuit Boards", filed Sept. 29, 1982 
now U.S. Pat. No. 4,470,101 (the entire disclosure thereof being expressly 
incorporated hereinto by reference), a novel apparatus was described for 
the mounting of printed circuit boards in a stacked coaxial relationship 
relative to one another as conventionally done for components in 
electrical equipment, e.g. aircraft instrumentation. As fully described in 
U.S. application Ser. No. 427,277, the invention thereof provides a novel 
system for the stacked assembly of printed circuit boards which 
facilitates the eccentric pivotal movement and isolation of selected 
boards out of the coaxial relationship so as to aid in the manufacture 
and/or repair thereof. 
The present invention is directed to a similar genre of devices in that an 
apparatus permitting the assembly of printed circuit boards in a stacked 
relationship is described. More particularly, the present invention is 
directed to a device which retains printed circuit boards in a stacked 
relationship transversely between front and rear supports. Although not 
necessary to the utilization of the present invention, the front support 
preferably includes an area for the mounting of visual read-out means for 
instrumentation data, etcetera. 
2. Description of the Prior Art 
Those in the art to which the present invention pertains have continually 
sought improved means for contiguously mounting an assembly of printed 
circuit boards as evidenced, for example, by reference to U.S. Pat. Nos. 
4,161,017 to Pierce et al; 3,257,585 to Ransom et al; 3,539,874 to 
Swanson; 3,596,140 to Walsh and 2,796,559 to Feucht. 
Pierce et al disclose a prior art device which permits pivotal movement of 
printed circuit boards about axes within or parallel to the planes defined 
by respective circuit boards. Thus, according to the proposal of Pierce et 
al, if a circuit board located relatively deep in the stack is to be 
isolated, all circuit boards prior to the desired board must be 
successively pivoted about their different respective axes to permit 
unobstructed access thereto. This arrangement is particularly 
disadvantageous if the circuit board assembly is located in an area of 
severe spatial limitations. Moreover, since the Pierce et al device 
contemplates pivotal movement about stacked axes, sufficient slack wire 
must be provided to permit the extent of pivotal movement necessary for 
each of the circuit boards in the assembly. It is surmised that upon 
pivotal movement of the circuit boards, portions of such slack wire may 
become pinched between the hinge mechanisms or otherwise restrict the 
intended hinge movements or be exposed to potential damage. 
Ransom et al disclose an assemblage of parallel electric or electronic 
component carrier units. According to Ransom et al, a plurality of 
component-carrier disc units are attached to a distribution board disk by 
separate flexible conductive strips radially extending from the 
distribution board disk, each conductive strip being anchored at one end 
to the distribution board disk and at the other end to a respective disk. 
Swanson discloses that a cradle structure having a plurality of spaced 
slots can be utilized to hold a stacked arrangement of printed circuit 
boards. However, as depicted in FIGS. 2 and 3 of the Swanson patent, when 
predetermined ones of the circuit boards are desired to be removed, they 
are simply lifted out of the engaging relationship with their associated 
slot. This form of an arrangement, therefore, utilizes only the 
interconnecting wiring per se as a means of maintaining the integrity of 
the assembly when one or more boards are removed from the cradle which 
could place unnecessary and potentially damaging stresses upon the points 
of wiring contact with the circuit boards. 
Walsh discloses a peripheral contact electronic circuit board assembly. The 
assembly of Walsh includes a plurality of circuit boards which can be 
separated from one another by tubular spacers. The circuit boards of Walsh 
include lugs protruding at regular annular intervals wherein electrical 
communication can be established between the outside world and the 
electronic components on the board via contact fingers in contact with 
conductive rails. Each of the circuit boards and spacers are contained in 
a cylinder which includes an array of rectilinear T-shaped slots defined 
in the inner wall parallel to the cylinder axis. Thus, in order to access 
a circuit board relatively deep in the cylinder, all boards and spacers 
prior thereto must first be slideably removed from the cylinder. 
Feucht discloses that a rigid spacer member can be utilized in combination 
with a plurality of circuit boards so as to maintain the separation 
distance therebetween. However, Feucht's main concern is to provide an 
apparatus permitting the assembly of circuit boards which operates as a 
heat sink so as to dissipate heat generated by the individual electrical 
components comprising his assembly. 
3. Summary of the Present Invention 
As the reader will undoubtedly appreciate from even the most cursory 
examination of the above prior art proposals, the present invention 
provides significant advances thereover in both structure and utility in 
that a circuit board assembly can be provided in accordance with the 
present invention which facilitates disassembly thereof in the event of 
repair and/or replacement of any component part yet is of high structural 
integrity when all component parts are assembled. 
Briefly stated, the present invention is directed to the assemblage of 
printed circuit boards, preferably substantially planar circuit boards, 
transversely between front and rear supports. The front and rear supports 
together define substantially aligned front and rear paired mounting slots 
into which the front and rear portions, respectively, of the printed 
circuit board are matingly received. Additionally, there is provided 
according to the present invention a snap ring connector which is seated 
in a circumferential recess preferably defined by each of the front and 
rear supports and engageable with indentations formed in circuit boards 
and mated with the circumferential recess to retain the circuit board in 
the associated mounting slots to provide overall rigidity to the assembly. 
While the present invention is particularly well suited for the transverse 
mounting of rectangular circuit boards for substantially cylindrically 
shaped instrumentation, etcetera, the concepts and principles of the 
present invention could similarly be employed in non-cylindrical 
instrumentation having circuit boards of other various geometric shapes. 
Thus, while the accompanying drawings and the detailed discussion thereof 
below may only describe rectangular printed circuit boards utilized in 
cylindrical instrumentation, the reader should realize that this merely 
represents a preferred embodiment in accordance with the present invention 
and is thus nonlimiting with respect thereto. 
It is fairly conventional in the electronic instrumentation art to provide 
a transformer unit in a contiguous relationship with its associated 
circuit boards. The present invention also provides a convenient, compact 
arrangement of a transformer or other electrical components within a bell 
housing so as to contiguously assemble it with the associated printed 
circuit boards. The bell housing preferably includes a pair of coaxially 
disposed gripping fingers which define an annular area with the interior 
surface of the bell housing into which the transformer is receivable and 
housed thereby. 
To establish electrical communication between the transformer, printed 
circuit boards and the outside world (e.g. sensors, other instrumentation 
and the like), an electrical connector is provided which mates with the 
transformer terminals and preferably defines at least partially arcuate 
edges which are secured (e.g. by means of solder or the like) to the bell 
housing. Multi-conductor ribbon connectors matable with printed circuit 
board terminals are also preferably provided. To complete electrical 
communication between the operative electrical components of the present 
invention with outside world, the connector is provided with multiple 
terminals adapted to matingly engage with a typical plug-in connector. The 
arcuate edges of the electrical connector closely mate with the interior 
surfaces of the gripping fingers and in the preferred embodiment of the 
present invention, are fixed thereto by means of solder or the like. 
To complete the assembly of the present invention there is preferably 
provided an opening concentrically defined in the rear support. The 
opening includes locking recesses so that upon assemblage of the 
transformer, electrical connector and bell housing, a portion of the 
exterior surface of the gripping fingers will mate with respective ones of 
the locking recesses of the opening so that upon manipulation of the bell 
housing to effect turning movement thereof relative the rear support (e.g. 
as by effecting 1/4 turning movement) locking engagement will be effected. 
In such a manner, all components of the assembly will be maintained in a 
structurally rigid manner yet will be capable of being quickly and easily 
disassembled in the event that repair and/or replacement of any component 
part becomes necessary. 
Other advantages and objects of the present invention will become more 
clear to the reader after careful consideration is given to the detailed 
discussion relating to the presently preferred exemplary embodiment 
thereof which follows.

DETAILED DESCRIPTION OF THE PREFERRED EXEMPLARY EMBODIMENTS 
An assembly 10 in accordance with one embodiment of the present invention 
is shown in FIG. 1 wherein the components thereof are depicted in a 
disassembled relationship for clarity of presentation. 
Assembly 10 generally includes front support 12 and rear support 14 between 
which a plurality of circuit boards 16A, 16B, 16C and 16D are transversely 
mounted. Although only four representative circuit boards are shown in 
FIG. 1, the reader should appreciate that any number of boards could be 
transversely mounted in accordance with the present invention, the upper 
limit of the number of boards utilized being determined by the spatial 
limitations of the particular instrument, electrical equipment, etcetera, 
with which the boards are associated. 
Front support 12 can, if desired, be provided with structure (e.g. lobes 
15) for mounting additional electronic equipment, visual read-out means, 
etcetera, thereto. Alternatively, front support 12 could be monolithic in 
appearance if deemed desirable or necessary. 
Interiorly disposed raised portions 16, 18 respectively integral with front 
and rear supports 12, 14 together define opposing paired slots 20A, 20B, 
20C and 20D into which a portion of the front and rear edges of circuit 
boards 16A, 16B, 16C and 16D are matingly receiveable, respectively. The 
separation distances between adjacent ones of paired slots 20A-20D will 
thus define the separation distances between adjacent ones of circuit 
boards 16A-16D. Moreover, as seen in FIG. 1, such separation distances 
need not be equivalent (although equivalent separation distances are 
contemplated) and, indeed, in practice it is surmised that it will be 
necessary to provide various unequal separation distances between the 
circuit boards owing to the inherent differences and spatial requirements 
of the circuit boards themselves. Accordingly, when circuit boards 16A-16D 
are matingly received in a respective one of paired slots 20A-20D, boards 
16A-16D will be transversely oriented with respect to front and rear 
supports 12, 14 and, moreover, will be disposed substantially parallel 
with respect to one another. 
Portions 16, 18 also define arcuate circumferential recessed areas 22, 24, 
respectively, which are disposed transversely to slots 20A-20D and which 
receive a resilient spring clip 26, 28. Boards 16A-16D preferably include 
indentations 30, 32 or similar structures which register with recessed 
areas 22, 24, respectively, when the circuit boards are engaged in slots 
20A-20C. Thus, due to the registrability of indentations 30, 32 with 
recessed areas 22, 24, the boards 16A-16D will be captured in a fixed 
position relative to one another when spring clips 26, 28 are seated in 
areas 22, 24, respectively. Of course, if any of boards 16A-16D are 
desired to be removed for testing, repair or the like, the spring clips 
26, 28 need only be unseated from areas 22, 24 and the desired board 
removed from its associated slot. 
Another aspect of the present invention is the contiguous assembly of e.g. 
a transformer 40 and electrical connector 42 with the assembled circuit 
boards 16A-16D as previously described. To accomplish this further aspect, 
a bell housing 44 having upstanding resilient fingers 46, 48 or equivalent 
structures is provided to establish locking unity between transformer 40 
and connector 42 on the one hand, and rear support 14 on the other hand in 
a manner which will now be specifically described. 
Transformer 40 is shaped so as to fit within the interior area of housing 
44 defined between fingers 46, 48 and interior surface 50. Fingers 46, 48 
each define an inner engaging surface 52 which can be, for example, in the 
form of a recessed arcuate slot for receiving and thus grippingly 
retaining a portion of the side edges 54, 56 of connector 42. Each of the 
fingers 46, 48 also defines an outer engaging surface 58 which can 
similarly be, for example, in the form of a recessed arcuate slot for 
receiving and thus grippingly engaging a portion of the arcuate aperture 
in rear support 14. 
Rear support 14 defines a central opening 60 having substantially opposing 
locking recesses 61, 62 defined on the circumferential edge thereof. Lobes 
63, 64 alternate with recesses 61, 62 so as to provide structure against 
which fingers 46, 48 are seated. Thus, upon assembly, fingers 46, 48 are 
initially positioned to allow passage through recesses 61, 62 so as to 
permit outer engaging surface 58 to register with a respective one of 
flanges 63, 64. Thus, upon turning movement (e.g. preferably 1/4 of a 
complete turn) of bell housing 44 relative rear support 14, outer engaging 
surfaces 58 will slideably engage with flanges 65 so as to rigidly retain 
housing 44 as a contiguous unit with boards 16A-16D. Disassembly, of 
housing 44 can, of course, be effected by reverse relative turning 
movement to that described above. 
In such a manner, the end bell housing 44, by virtue of fingers 46, 48 
permit transformer 40 and connector 42 to be securely housed thereby while 
yet effecting structural rigidity between housing 44 and rear support 14. 
Since fingers 46, 48 are slideably engaged with flanges 65, housing 44 may 
be separated therefrom to obtain access to the various components in 
assembly 10 by effecting turning movement therebetween until uncoupling is 
permitted. 
Electrical communication can be established between transformer 40 and 
connector 42 by pins 70 while connector 42 establishes communication with 
boards 16A-16D by multi-conductor flexible ribbons 72, 74 connected to 
appropriate connecting pins on predetermined ones of the circuit boards 
(for example, ribbon 70 can be connected to board 16A by pins 76 as shown 
in FIG. 1). Arcuate openings 78 permit ribbon connectors 72, 74 to pass 
through rear support 14. Communication can also be established between 
circuit boards utilizing multi-conductor ribbons 80, 82 as shown in FIG. 1 
in a manner known to those in this art. Other means of effecting 
electrical communication between electronic components can also be 
utilized and as these other means are also believed to be known to those 
in this art, a detailed discussion thereof appears unnecessary. Finally, 
electrical communication between assembly 10 and the outside world can be 
established utilizing a conventional multi-pin plug-in connector 84 
adapted to being seated or fixed in aperture 86 of housing 44, the pins of 
which establish electrical contact with connector 42. A cable (shown at 88 
in FIG. 2) can be provided with connector 84 in a conventional fashion. 
A particularly preferred embodiment of the assembly 100 in accordance with 
the present invention is depicted in accompanying FIGS. 3 and 4. 
Generally, the embodiment of assembly 100 is similar to the embodiment of 
assembly 10 described above in that circuit boards 16A-16D are 
transversely mounted between front and rear supports 12, 14, respectively. 
Accordingly, like reference numerals in accompanying FIGS. 3 and 4 denote 
like structural elements with regard to the embodiment depicted in FIGS. 1 
and 2, and thus the reader's attention is directed to the discussion above 
for the functional characteristics thereof. 
The primary distinction between the assembly 100 shown in accompanying 
FIGS. 3-4 and assembly 10 shown in accompanying FIGS. 1-2 relates to the 
assemblage of bell housing 44 (and thus transformer 40) with rear support 
14 so as to provide a substantially rigid, contiguous unit. Thus, whereas 
the assembly of the FIGS. 1-2 embodiment accomplishes this rigid 
interconnection by virtue of outer engaging surfaces defined by gripping 
fingers 46, 48 being engaged with interior circumferential flanges 65 upon 
relative turning movement between housing 44 and rear support 14, the 
rigid interconnection of the FIGS. 3-4 embodiment is effected by virtue of 
locking flanges 102, 104 provided on the leading edge of bell housing 44 
cooperating with locking recesses 106, 108 defined on the exterior 
circumferential edge of rear support 14. Thus, end bell housing 44 is 
initially positioned relative rear support 14 so that flanges 102, 104 
register with recesses 106, 108, respectively, and rigid locking 
interengagement will be effected by virtue of flanges 102, 104 being 
slideably turned into locking engagement with flanges 110, 112 of rear 
support 14. 
Prior to assembly of end bell housing 44 onto rear support 14, transformer 
40 is placed into the interior space defined by the former. Connector 114 
is positioned onto pins 116 so that electrical communication can be 
established in a manner similar to that described above with respect to 
connector 42 of the FIGS. 1-2 embodiment. In accordance with the FIGS. 3-4 
embodiment, connector 114 is held securely in place not only by virtue of 
engagement with pins 116, but also by virtue of recessed area 120 defined 
around the circumferential edge of opening 122 on the rear face of rear 
support 14. Thus, connector 114 seats in area 120 so as to be held therein 
when bell housing 44 is lockably interengaged with rear support 14. 
While terms such as circular, arcuate, cylindrical and the like have been 
utilized above to describe the geometry of the presently preferred 
embodiment of the present invention, other geometric forms are well within 
the contemplation of the present invention. Thus, for example, fingers 46, 
48, bell housing 44, edge 60, recessed areas 22, 24 and front and rear 
supports 12, 14 could be any other geometric form (e.g. square, 
rectangular, etcetera) as required. 
Furthermore, it should be noted that although circuit boards 16A-16D have 
been depicted as being transversely mounted between front and rear 
supports 12, 14 in a horizontal fashion, vertical or other angular 
dispositions of boards 16A-16D transversely between front and rear 
supports 12, 14 is also contemplated. Thus, any angular relationship of 
the boards 16A-16D with respect to horizontal can be achieved in 
accordance with the present invention as long as they are mounted 
substantially transverse to the front and rear supports 12, 14. 
While the present invention has been herein described in what is presently 
conceived as being the most preferred embodiment, those in the art will 
recognize that many modifications and variations may be made while still 
retaining many of the novel features and advantages of this invention. 
Accordingly, all such modifications and variations are intended to be 
within the scope of the following claims.