Modular EMI-EMP connector assembly

A modular electrical connector assembly includes a shell containing a plurality of separate bays, each bay being adapted to accept an EMI/EMP electrical connector insert or module. A unique latch structure enables each connector module to be easily removed from its bay to enable fast and easy replacement of defective modules or the EMI/EMP components contained therein.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to the field of electrical connectors, and in 
particular to electrical connectors having filtering and/or transient 
suppression capabilities. 
2. Description of Related Art 
Electrical connectors which protect electrical circuits from 
electro-magnetic interference (EMI) and transient signals such as 
electromagnetic pulses (EMP), lightening and other voltages having pulses 
of extremely short duration and high amplitudes have become increasingly 
indispensable in a variety of electrical connector applications, in 
particular in military and aerospace applications. As such connectors 
become increasing common, issues of compatibility, ease-of-use, cost, and 
repairability take on increasing significance. 
In the initial stages of the development of a new technology, 
standardization and mass production are primary objectives. Later in the 
development of the new technology, however, modularization, in which the 
customer is able to adapt a design to his particular requirements by 
arranging a variety of standard or custom components within a common 
framework, becomes an attractive option. Often, a modular product can 
render obsolete the original standardized design. 
At this stage in the development of the technology, seemingly minor 
improvements can make a big difference. The key to the success of a new 
modular design can, for example, be as simple, and unexpected, as an 
improved latch which permits easy replacement of the module. The present 
invention involves such a breakthrough latch design. While simple in 
concept and implementation and superficially similar to latches used in 
other contexts, the inventive latch nevertheless represents a fundamental 
change which permits modularity to be achieved in the context of 
electrical connectors of the type which use EMI or EMP components. 
Plural connector assemblies have previously been proposed, and a variety of 
latches are known for mating separate connectors together, but none of 
these designs is suitable for use as part of an EMI/EMP system in which 
the individual components in the connectors are desirably removed for 
repair or replacement. In fact, a prior modular assembly, disclosed in 
U.S. Pat. No. 4,659,163, teaches that the filter components in an EMI/EMP 
system should be fixed in the modular housing frame, rather then removable 
with the modules. 
Because the technology of transient suppression and filter components 
designed to fit within connectors is well developed, the present invention 
concerns the interface between the modules and the modular housing rather 
than with a specific arrangement for fitting components within the 
modules, although one particular arrangement for fitting EMI/EMP 
components in a module is disclosed. The invention thus concerns a latch, 
and also a seal and a ground arrangement for the module with advantages in 
the areas of ease-of-use, cost, and repairability, rather than filtering 
performance. Although simple in design, the invention nevertheless 
represents a significant improvement in a technology which has reached the 
point where evolutionary changes can have revolutionary results. 
SUMMARY OF THE INVENTION 
It is a first objective of the invention to provide a modular filter and/or 
transient suppression (EMI-EMP) connector assembly in which individual 
connector dimensions are within present connector envelopes, and which 
allows for easy interchangeability and replacement of unprotected 
connectors already in the field. 
It is a second objective of the invention to provide an EMI/EMP connector 
assembly which utilizes otherwise standard EMI-EMP connectors which are 
modified to include an improved latch for providing secure retention of 
the connectors in the assembly and easy removability. 
It is a third objective of the invention to provide a modular EMI-EMP 
connector assembly which provides secure retention of the connector 
modules in the assembly and an effective grounding and sealing arrangement 
for each individual connector module. 
These objectives are achieved by providing a modular electrical connector 
assembly which uses a standard ARINC 600-type interface, and provides for 
front removability of damaged or questionable EMI-EMP connector modules, 
thus permitting removal and replacement without tieing up valuable time 
for testing, and without requiring disconnection of the cables or PCB to 
which the rear portions of the connector modules are attached. Each filter 
element is grounded to a housing of the assembly through a continuous, 
replaceable groud spring, ensuring that the ground path has a minimum 
amount of inductive, capacitive, and resistive reactance while providing 
optimum filter performance, the transient suppression elements being 
grounded to the housing by a conventional ground plate design of proven 
reliability and effectiveness. Sealing is provided by an interfacial seal 
at the rear of each module, in cooperation with standard seals provided in 
the modules themselves. 
The retention latch is a molded-in two-tine latch which, when pushed into 
the housing and past a specially designed shell undercut, compresses and 
snaps back to hold the insert in place. To remove the insert, an insert 
removal tool is placed over the tines, compressing the tines so that they 
no longer latch onto the shell undercut. When the tool has compressed the 
tines and is pushed sufficiently into the housing, a pair of protrusions 
or hooks provided on the removal tool engage insert removal nubs provided 
on the connector module which allow for the insert to be pulled out. The 
tines preferably extend parallel to the connector module housing, with 
hooks extending perpendicular to the direction of insertion, in the plane 
tangential to a sidewall of the connector module housing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIGS. 1 and 2 are, respectively, front and side views of a preferred 
connector assembly 1 having three connector insert bays 2-4. A plurality 
of interface contacts 5 and all TVS or filter components (described in 
more detail below) are contained in connector inserts or modules 6, 6', 
and 6" which are arranged to fit within bays 2-4. The number of bays is of 
course optional, as are the type of components contained within the 
inserts 6, 6', and 6", although a particularly advantageous configuration 
for TVS and filter components is shown in FIG. 5. 
The preferably metal shell 7 of connector assembly 1 includes a main 
housing frame 8 and a flange 9 having apertures 10 for mounting the 
assembly on a panel. Shell 7 is illustrated as being provided with PCB 
tails 11 to which contacts 5 are electrically connected, PCB tails 11 
forming means for electrically connecting contacts 5 with electrical 
conductors, such as circuit board traces, in an electrical device. In 
addition, one of the bays 4 is shown as being provided with crimp socket 
contacts 12 and an E-grommet 13, the contacts 5' of the insert 6" being 
modified accordingly. Insert 6' is identical to insert 6. 
Turning to FIG. 5, the TVS contacts 5 contained in the exemplary connector 
insert or module 6 are of known type and include socket mating section 14 
and a TVS component mounting section 15 on which is mounted a diode 16 
electrically connected to a conductive ground sleeve 17. The ground sleeve 
17 is fitted around contact 5 and an insulator sleeve (not shown) and 
grounded to main housing frame 8 by ground plate 18. Ground plate 18 
includes a plurality of tines 19 around its periphery which extend from 
the insert to resiliently engage an inner surface 20 of frame 8. 
Electrical contact between the ground sleeve 17 and ground plate 18 is 
established by tines 21 extending from edges of the apertures through 
which contacts 5 pass. In order to form the connector insert or module, 
ground plate 18 is sandwiched between and affixed to a dielectric front 
insert 22 and a dielectric rear insert 23. 
For ease of repairability, contacts 5 are formed in two parts, the first 
part including sockets 14, mounting section 15 and end portions 24 which 
mate with socket portions 25 of rear contact halves 26. Rear contact 
halves 26 extend through insert 23, ferrite filter elements 27, a 
monolithic filter capacitor 28, a dielectric spacer element 29, and an 
interfacial seal 30. 
Rear contact halves 26 include termination ends 31 which are inserted into 
sockets 32 provided on PCB tails 11. PCB tails 11 extend through and are 
secured by a dielectric back portion 33 of the otherwise metal housing 
frame. Alternatively, the insert contacts may terminate in the crimp 
socket 12 and E-grommet 13 arrangement shown for bay 14 in FIG. 2. The 
monolithic filter capacitor 28 is grounded to housing frame 8 via a ground 
strap 34 which contacts an electrode 35 provided around the periphery of 
capacitor 28 and which is retained in the housing 8 by engagement between 
an extension 36 end of strap 34 and a notch or groove 37 provided in frame 
8. 
As shown in FIGS. 3 and 4A-E, U-shaped retention latch 38 is molded into 
front insert 22 and includes two tines 39 having camming sections 40, main 
sections 41 and hook portions 42. Hook portions 42 also include camming 
portions 43 and extend outwardly within a plane which is tangential to a 
side of the connector insert or module in order to be received within a 
specially designed undercut 44 in the main housing frame 8. 
On each side of the latch, an insert removal nub 51 is also molded into the 
front insert 22. Each nub 51 includes a camming surface 52 and a bottom 
surface 53 whose function will become apparent below. The undercut 44 
extends in the direction of insertion of the connector insert and has two 
sections, one section 45 of which has a width which is less than the 
normal unstressed distance between tips of hook portions 42 on the latch. 
The second section 46 of undercut 44 is wider than the unstressed distance 
between portions 42 to form shoulders 47. 
Insertion of the connector inserts or modules into the shell is 
accomplished as follows: 
When the connector insert latch 38 is pushed into the assembly 1, it 
compresses as camming portions 43 of hooks 42 engage the narrow portion 45 
of undercut 44. After hooks 42 clear portion 45 and enter wider portion 
46, tines 39 snap back to cause the hooks to engage the shoulders and hold 
the connector module or insert in the shell. 
Removal of the connector inserts or modules form the shell is accomplished 
as follows, with reference to FIGS. 4A to 4E: 
During removal, a removal tool having two flexible tines 48 and hooks 49 
including camming portions 50 is inserted (see FIG. 4A) such that hooks 49 
on the removal tool engage both the camming portions 40 of the latch 
member and the camming portion 52 on removal nub 51 to cause main portions 
or tines 39 to flex inwardly and cause the hooks 42 to disengage the 
shoulders 47 as shown in FIGS. 4B and 4C. Upon continuing to be pushed 
into the connector module bay, hooks 49 are compressed by the insert 
removal nubs 51 until they pass the nubs, as shown in FIG. 4D, at which 
time hooks 49 engage the bottom surfaces 53 of the removal nubs 51, while 
at the same time holding the latch hooks 42 away from the shoulders 47, 
and permitting the connector module to be pulled out of the assembly, as 
illustrated in FIG. 4E. 
Having thus described an example of a modular connector assembly in 
accordance with a specific preferred embodiment of the invention, it will 
nevertheless be appreciated that the invention should not be limited by 
the above disclosure since it is anticipated that numerous variations of 
the invention will occur to those skilled in the art. Therefore, it is 
intended that the invention be limited solely by the appended claims and 
not by the above disclosure or illustrations.