U.S. patent application number 09/999351 was filed with the patent office on 2003-05-15 for apparatus and method for using a backshell.
Invention is credited to Baerman, Roger A., Bodle, John W., Eddy, Brett A., Hirschberg, Robert N., Overman, Rob.
Application Number | 20030092307 09/999351 |
Document ID | / |
Family ID | 25546231 |
Filed Date | 2003-05-15 |
United States Patent
Application |
20030092307 |
Kind Code |
A1 |
Hirschberg, Robert N. ; et
al. |
May 15, 2003 |
APPARATUS AND METHOD FOR USING A BACKSHELL
Abstract
A backshell for forming an electrical connection with a cabinet,
the backshell including at least one electrical connector, a
deflection arm coupled to one end of the backshell for engaging a
cam on a cabinet which holds a receiving connector, and a fastener
on the opposite end of the backshell from the deflection arm. The
deflection arm provides a clamping force when the fastener is fully
engaged, and helps form a strong mechanical connection.
Inventors: |
Hirschberg, Robert N.;
(Glendale, AZ) ; Baerman, Roger A.; (Glendale,
AZ) ; Bodle, John W.; (Phoenix, AZ) ; Eddy,
Brett A.; (Phoenix, AZ) ; Overman, Rob;
(Phoenix, AZ) |
Correspondence
Address: |
HONEYWELL INTERNATIONAL INC.
101 COLUMBIA ROAD
P O BOX 2245
MORRISTOWN
NJ
07962-2245
US
|
Family ID: |
25546231 |
Appl. No.: |
09/999351 |
Filed: |
November 15, 2001 |
Current U.S.
Class: |
439/362 |
Current CPC
Class: |
H01R 13/6395 20130101;
H01R 12/7005 20130101; H01R 13/6272 20130101; H05K 7/1452 20130101;
H01R 13/6215 20130101 |
Class at
Publication: |
439/362 |
International
Class: |
H01R 013/627 |
Claims
The following is claimed:
1. An electronic signal connection apparatus comprising: a
backshell having a first end and a second end opposite the first
end; at least one electrical connector within the backshell; a
deflection arm coupled to the first end; and a fastener coupled to
the second end.
2. The apparatus of claim 1 further comprising a cable bundle
exiting the backshell through the first end.
3. The apparatus of claim 1 further comprising a cable bundle
exiting a rear portion of the backshell at a predetermined
angle.
4. The apparatus of claim 1 wherein each electrical connector is a
D subminiature type connector.
5. The apparatus of claim 1 further comprising: a tab forming a
part of the deflection arm configured to align the connector with a
receiving connector in a cabinet; the tab engaging a receiving
notch in a cam, and the cam being coupled to the cabinet.
6. The apparatus of claim 1 further comprising an alignment pin for
aligning the connector to a receiving connector; the alignment pin
having a curvature for radial insertion into an aligning hole.
7. The apparatus of claim 1 further comprising a key coupled to a
face plate on the backshell and a key receiver coupled to a
cabinet; the key receiver configured to receive the key.
8. The apparatus of claim 1 wherein the fastener is a jack
screw.
9. The apparatus of claim 1 further comprising at least one of the
following within the backshell: a Deutsch block, a grounding strap,
and an aircraft personality module.
10. The apparatus of claim 1 further comprising a Tag Ring in
proximity with the backshell.
11. An electronic signal connection apparatus comprising: a
backshell having a first end and a second end opposite the first
end; at least one electrical connector coupled to the backshell; a
deflection arm coupled to the first end; a fastener coupled to the
second end; a cabinet comprising at least one receiving electrical
connector; and a cam coupled to the cabinet, the cam configured to
engage the deflection arm.
12. The apparatus of claim 11 further comprising a cable bundle
exiting the first end.
13. The apparatus of claim 11 further comprising a cable bundle
exiting a rear portion of the backshell at a predetermined
angle.
14. The apparatus of claim 11 wherein the electrical connector is a
D subminiature type connector.
15. The apparatus of claim 11 further comprising a tab on the
deflection arm, the tab configured to align the connector with the
receiving connector on the cabinet, and the tab engaging a
receiving notch in the cam.
16. The apparatus of claim 11 further comprising an alignment pin
configured to align the connector to the receiving connector; the
alignment pin having a curvature for radial insertion into an
aligning hole.
17. The apparatus of claim 11 further comprising a key coupled to a
face plate on the backshell and a key receiver coupled to the
cabinet; the key receiver configured to receive the key.
18. The apparatus of claim 11 wherein the fastener is a jack
screw.
19. An electrical connection apparatus comprising: a backshell
configured to form at least one electrical connection; the
backshell having a first end and a second end opposite the first
end; a deflection arm coupled to the first end; and a single
fastener coupled to the second end.
20. The apparatus of claim 19 further comprising a cable bundle
exiting the backshell through the first end.
21. The apparatus of claim 19 further comprising a cable bundle
exiting a rear portion of the backshell at a predetermined
angle.
22. The apparatus of claim 19 wherein the electrical connector is a
D subminiature type connector.
23. The apparatus of claim 19 further comprising a tab forming a
part of the deflection arm configured to align the connector with a
receiving connector coupled to a cabinet; the tab engaging a
receiving notch in a cam, and the cam being coupled to the
cabinet.
24. The apparatus of claim 19 further comprising an alignment pin
configured to align the connector to a receiving connector; the
alignment pin having a curvature configured to be radially inserted
into an aligning hole.
25. The apparatus of claim 19 further comprising a key coupled to a
face plate coupled to the backshell and a key receiver coupled to a
cabinet; the key receiver configured to receive a matching key.
26. The apparatus of claim 19 wherein the fastener is a jack
screw.
27. An electrical connection apparatus comprising: a backshell
configured to form at least one electrical connection; a D
subminiature type connector configured to be supported by the
backshell; a receiving D subminiature type connector configured to
be supported by a cabinet; and at least two fasteners coupled to
the backshell; the fasteners configured to provide a force which
maintains the electrical connection by maintaining constant
engagement between the backshell and the cabinet.
28. The apparatus of claim 27 wherein the fastener is a jack
screw.
29. The apparatus of claim 27 further comprising an alignment pin
configured to align the connector to a receiving connector.
30. The apparatus of claim 27 further comprising a cable bundle
exiting a rear portion of the backshell at a predetermined
angle.
31. The apparatus of claim 27 further comprising a key coupled to a
face plate on the backshell and a key receiver coupled to the
cabinet, the key receiver configured to receive the key.
32. A method for using a backshell comprising the steps of:
engaging a deflection bar with a cam, the deflection bar being
coupled to one end of the integrated backshell, the cam being
coupled to a cabinet; rotating the backshell into position to
engage a connector on the integrated backshell with a mating
connector on the cabinet; and fixedly attaching the integrated
backshell to the cabinet using a single fastener.
33. A method for using a backshell comprising the steps of:
engaging a deflection bar on the backshell with a cam coupled to a
cabinet, the deflection bar being coupled to one end of the
integrated backshell; rotating the integrated backshell into
position to engage a connector on the backshell with a mating
connector on the cabinet; and securing the backshell in clamped
engagement with the cabinet to maintain an electrical connection;
the securing step being performed with a single fastener.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention relates generally to electronic signal
connectors and, more particularly, to a backshell configuration for
providing a mechanical connection for communicating signals in a
rigorous vibration environment.
[0003] 2. Background Information
[0004] Electrical connections are commonly used in transmitting
signals and data between computers, systems and other devices.
Typically, one device is connected to another device or system
through a single wire or multiple wires. In many instances, a cable
bundle containing these wires terminates in a mechanical housing,
also known as a backshell, which provides physical protection for
each wire in the cable bundle to each pin in an apparatus for
making mated connections in the connected device. A backshell also
protects the wires and connectors from fatigue. For example, FIG. 1
shows a typical prior art connection between a device 10 and a
cable bundle 20 containing multiple wires 22. The cable bundle 20
terminates in a mechanical housing also known as a backshell 30.
Generally, some form of mechanical connection is provided to
prevent the backshell from becoming disconnected from the connected
device and to maintain the signal contact at all times. For
example, in the exemplary embodiment shown in FIG. 1, two No. 4
size screws 40 are provided with thumb adjustment knobs to provide
this mechanical connection.
[0005] U.S. Pat. Nos. 4,579,415, 5,348,482, 5,788,528, 5,855,493,
5,911,595, 5,961,348 discuss typical backshell constructions,
magnetic grounding techniques in backshells, cable strain relief
techniques, and the cabinets to which the backshell connectors may
be attached. The general functionality of these patents is
incorporated by reference as background information.
[0006] While this sort of connection may be sufficient in some
applications, a large number of situations exist where the
environment provides particularly challenging conditions which may
cause the mechanical connection to fail. The failures may be a
permanent disconnection of the wires resulting in a permanent
interruption in the signals being transmitted or communicated, or
may be temporary or intermittent open circuits which distort or
destroy the signal integrity. In many applications, even a
momentary disruption in signal integrity can have very undesirable
results.
[0007] Electrical connections which are made between avionics
devices are often subject to a rigorous vibrational environment.
For example, helicopters and fixed-wing aircraft experience a broad
range of vibrations and temperature swings. These vibrations may
loosen the connectors 40 over a period of time, such as by
unscrewing or stripping the threads of connectors 40. Also, the
small No. 4 size screws 40 can slip and fail to maintain the
connection under rigorous environmental conditions. Furthermore,
the vibrations may cause the connection point between the wires of
the device and the wires in the backshell to disengage unless
constant pressure keeps the wires held together. Although the
present discussion focuses primarily on the rigorous vibrational
environments found in fixed-wing aircraft and helicopters,
similarly challenging environments may be found in pumps, fans,
motors, and other large machinery found, for example, on oil rigs,
shop floors, and other such high vibration applications.
Furthermore, connections between cable bundles and electrical
devices may be challenged by other environmental factors such as
high temperatures, or large temperature changes, low and high
humidity conditions and electromagnetic radiation environments. For
all of these conditions, it is desirable to have a strong
mechanical connection to maintain signal integrity.
[0008] Connections in avionics devices typically use an ARINC 404
connector such as, for example, a DPX model connector available
from Cannon, mil number, MIL-C-81659. ARINC stands for Air Radio
Inc. ARINC 404 is a specification, known to those of skill in the
art, that defines air transport avionics equipment interfaces.
ARINC 404 connectors tend to perform well in the high vibration
environment found in avionics. However, due to the use of smaller
and lighter devices and systems in aircraft, some manufacturers
have moved away from the ARINC 404 connectors and have begun
manufacturing devices that require connectors such as the D
subminiature connectors. These D subminiature connectors, when
attached by methods of the prior art, may not be mechanically
robust and may lack the ability to provide a reliable signal.
Furthermore, the prior art D subminiature type connectors are
bulky, often difficult to install, and lack packaging
efficiency.
[0009] The trend in avionics is to use smaller and lighter
components to improve the performance of aircraft. Thus,
manufacturers have combined multiple devices into smaller packages.
One difficulty that has been encountered with the use of the D
subminiature connectors is that cabinet 15 (such as the cabinet
illustrated in FIG. 1) which contains one or more devices 10 is
typically very small and leaves little room for accessing the thumb
screws 40. Moreover, standard backshells are a difficult fit in
congested avionics bays.
[0010] The tight spacing tolerances also make it difficult to use
the standard D subminiature connectors because in some situations,
the cabinet 15 may be located so close to device 10 that, although
there is room for the backshell 30 between the device 10 and
cabinet door 16, there may not be room for the cable bundle 20 to
come out of end 32 of backshell 30 so as to not interfere with the
closing of cabinet door 16. This interference, for example, can be
shown in FIG. 1 at interference point 28. It will be readily
appreciated, however, that if cable bundle 20 exits backshell 30 on
either top side 34 or bottom side 36, it would be more difficult to
access connectors 40 to tighten backshell 30 to device 10. In some
situations, more than one connector is attached to the device 10.
When these connections are in line and close together, it is harder
still to obtain access to the mechanical fasteners.
[0011] Moreover, the screws 40 used to attach standard D
subminiature connectors are limited to the small No. 4 size screws
that fit into standard D subminiature threaded screw receiving
holes in the mating D subminiature connector. Therefore, it has
been difficult to provide a means of mating the D subminiature
connector with any other fastener other than these small screws,
and it has thus been difficult to form a connection which can
withstand the rigorous vibration environments found in aircraft
avionics bays.
[0012] Therefore, a need exists for an integrated backshell that
fits the tight confines of avionics bays while allowing access to
the connectors. A further need exists for an integrated backshell
that accommodates multiple connectors for efficient use of space,
simplification of making connections, and added assurance of making
the connections at the right places. There is a further need for a
strong mechanical connection that can withstand a rigorous
vibrational environment.
SUMMARY OF THE INVENTION
[0013] The following summary of the invention is provided to
facilitate an understanding of some of the innovative features
unique to the present invention, and is not intended to be a full
description. A full appreciation of the various aspects of the
invention can only be gained by taking the entire specification,
claims, drawings, and abstract as a whole.
[0014] In an exemplary embodiment, a back shell is provided for
forming an electrical connection with a cabinet, the backshell
comprising at least one electrical connector, such as a D
subminiature connector, a deflection arm coupled to one end of the
back shell for engaging a cam on a cabinet which holds a receiving
connector, and a fastener, for example, a captive mechanical
jackscrew, on the opposite end of the backshell from the deflection
arm. The deflection arm provides a clamping force when the fastener
is fully engaged, and helps form a strong mechanical connection. In
another exemplary embodiment, a mechanical jackscrew is provided on
both ends of the backshell for securing the backshell to the
cabinet.
[0015] The novel features of the present invention will become
apparent to those of skill in the art upon examination of the
following detailed description of the invention or can be learned
by practice of the present invention. It should be understood,
however, that the detailed description of the invention and the
specific examples presented, while indicating certain embodiments
of the present invention, are provided for illustration purposes
only and that various changes and modifications within the spirit
and scope of the invention will become apparent to those of skill
in the art from the detailed description of the invention and
claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The subject invention will hereinafter be described in
conjunction with the appended drawing figures wherein like numerals
denote like elements, and
[0017] FIG. 1 is a schematic representation of an exemplary
connection in the prior art;
[0018] FIG. 2 is a side perspective isometric drawing of an
exemplary embodiment of the present invention;
[0019] FIG. 3 is a side view of an exemplary embodiment of the
present invention; and
[0020] FIG. 4 through FIG. 8 are exploded isometric views of
exemplary embodiments of the present invention.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0021] An apparatus and method for using the apparatus in
accordance with various aspects of the present invention provide an
improved electrical signal connection for avionics related
backshells. In this regard, the present invention may be described
herein in terms of functional block components and various
processing steps. It should be appreciated that such functional
blocks may be realized by any number of components configured to
perform the specified functions. For example, the present invention
may employ various magnetic radiation grounding techniques, such as
Deutsch grounding blocks, lug terminations, Tag Rings, and the
like. Tag Ring is a brand name for a 360 degree EMI shield produced
by Glenair. Furthermore, a variety of mechanical fasteners may be
used to secure a backshell to a cabinet. Such general components
that are known to those skilled in the art are not described in
detail herein. It should further be understood that the exemplary
process or processes illustrated may include more or less
steps.
[0022] With reference to FIG. 2, the present invention comprises an
integrated backshell 200 shown mated to a modular avionics unit
(MAU) module or cabinet 280. MAU 280 is made, for example, by Tella
Tool & Mfg of Lombard, Ill. The present invention, in one
exemplary embodiment, further comprises an electronic signal
connection apparatus comprising: a backshell 200 configured to hold
an electrical signal connection device, and the backshell 200
further configured to maintain the electrical connection by holding
backshell 200 securely to the MAU 280. In one exemplary embodiment,
the backshell securing configuration further comprises a first end
34 and a second end 36 opposite the first end, wherein a deflection
arm 220 is coupled to the first end 34 and a fastener 230 is
coupled to second end 36, and wherein deflection arm 220 and
fastener 230 combine to create a clamping force to securely hold
backshell 200 to MAU 280.
[0023] An exemplary integrated backshell 200 is shown in FIG. 2 in
an installed position. Integrated backshell 200 is shown connected
to MAU cabinet 280 via an MAU module front plate 282. In this
embodiment, the backshell 200 may support two D subminiature
connectors associated with two cable bundles. The cable bundles are
not shown in this figure for the sake of clarity, but would exit
through counter bored clearance holes 210 located at the top end 34
of backshell 200.
[0024] It will be noted that because cable bundles exit the top 34
of backshell 200, it would be very difficult to have access to a
bolt or screw for connecting to the top connector 240. Therefore, a
deflection arm 220 (or bar) provides an alternative means of making
a mechanical connection. Deflection arm 220 engages a cam 290
located at the top portion of MAU cabinet 280. Cam 290, in this
embodiment, is bracket-shaped such that deflection arm 220 may be
positioned under the bracket portion of cam 290. Of course, other
shapes or configurations may be used for cam 290 and deflection arm
220 so long as the two devices may interact to form a clamping
force. Cam 290 also contains slots 292 for engaging tabs 222 on
deflection arm 220. The slot 292/tab 222 assembly arrangement
enables improved alignment in installing backshell 200.
[0025] Deflection arm 220 may suitably be made of aluminum alloy in
one embodiment of the present invention. Deflection arm 220 may
also be made of material such as, for example, 6061-T651 aluminum
alloy, spring steel, and beryllium copper. In avionics, materials
are often chosen for their light weight, which makes materials such
as aluminum favorable for use. Other suitable materials, however
may also be used such as, for example, glass, nylon, polycarbon,
and carbon-fiber. In one embodiment of the present invention,
deflection arm 220 causes a pressure to be created forcing
backshell 200 to remain in contact with MAU cabinet 280 when
engaged with cam 290. Therefore, deflection arm 220 should
preferably be configured to provide the necessary force to
constrain the backshell in its mounting under the applied loads as
required due to the environment to which the electronics shall be
subjected.
[0026] In the embodiment shown in FIG. 2, only one fastener 230 is
used to secure backshell 200 to the MAU cabinet 280. The fastener
is located at the opposite end from deflection arm 220, which in
this embodiment is the bottom 36 of backshell 200. This fastener is
connected to backshell 200, and may be, for example, a screw-type
fastener. Screw 230 engages bottom connector 242 and provides the
second pressure point for holding backshell 200 to the MAU cabinet
280. Screw 230 may be, for example, a No. 10 size screw with
locking capabilities, such as Part No. 7027042 provided by
Honeywell Manufacturer. Other jackscrews and fasteners may be used
in other exemplary embodiments.
[0027] With reference to FIG. 3, a detailed side view of the
preferred relationship between cam 290 and backshell deflection arm
220 is shown. In this view, deflection arm 220 is shown with tab
222 engaging cabinet cam 290. Deflection arm 220 is shown to be
preferably shaped such that it clears module jack screw 240 and
such that a very small interference (for example, 15 thousandths to
14 thousandths of an inch) is created between the deflection arm
220 and the cabinet cam bar 290. In an exemplary embodiment, the
amount of interference is dictated by the clamping force desired to
maintain a stable and reliable mechanical and electrical interface.
As discussed above, this determination of the desired clamping
force may be a function of the vibration environment and backshell
vibration response. In some embodiments, resistance to vibration
may not be a concern, such as on a shop floor where shock might be
more of a concern or shop floor personnel bumping up against the
equipment and loosening the electrical connection. This
interference will preferably cause an appropriate amount of
pressure to be placed on deflection arm 220 to deflect the arm.
Also visible in FIG. 3 is the cabinet 280 and a curved portion of
cabinet sheet metal 284 which provides added stiffness. MAU module
front plate 282 is also visible in FIG. 3.
[0028] With reference now to FIG. 4, an exploded isometric view of
the internal construction of an exemplary backshell 200 is shown.
Backshell 200 is made of a base housing 201 with a mated cover 202
which contains all the components internal to the backshell. The
housing and cover may be made, for example of 6061-T651 aluminum.
Backshell 200 further has a deflection arm 220 formed as an
integral part of, or otherwise rigidly attached to, base housing
201 or cover 202. Deflection arm 220 may also be attached in other
ways known in the art so long as deflection arm 220 is securely
attached to the backshell structure. Jack screw 230 is shown with
washers for use in attaching backshell 200 to cabinet 280 as
discussed with reference to FIG. 2. Drainage holes 204 are
optionally shown in bottom 36 of backshell 200 for providing a
drainage route for condensation or any other moisture buildup.
Drainage holes make backshell 200 more able to withstand
temperature and humidity environmental conditions, as well as shed
other moisture which might get into backshell 200. Two cable
bundles 260 are shown entering the backshell housing through holes
210 through top 34 of backshell 200.
[0029] The "top" 34 and "bottom" 36 of backshell 200 have been
identified with reference to one exemplary embodiment. However,
those of skill in the art will now realize that deflection arm 220
could be coupled to backshell 200 on either the top or bottom ends
of the backshell. Mechanical fastener 230 is generally located at
the opposite end of backshell 200 from the end where deflection arm
220 is attached. Furthermore, cable bundles 260 may exit through
the top end, bottom end, and rear end of backshell 200. If the
cable bundles exit through a top or bottom end, it will be through
the deflection arm end to leaving the other end free to allow a
person easier access to mechanical fastener 230. The drain may be
exclusively used on the bottom of backshell 200 for obvious gravity
drainage reasons.
[0030] Cable bundle 260 enters backshell 220 through, for example,
one or more counter-bored clearance holes 210. Common rubber
grommets 530 are installed over cable bundles 260. Grommets 530 fit
into clearance holes 210 which conform to the outside dimensions of
the grommets 530. A shoulder on grommet 530 mates with a
counter-bore in clearance hole 210 to capture grommet 530 and not
allow it to work its way out of backshell housing 200. Cable
bundles 260 may be secured to base housing 201 in a variety of
places using a cable strap and screw assembly 262.
[0031] The cable bundles may contain multiple wires 22 (not shown)
which exit the cable bundles at 264 and connect to dual D
subminiature connectors 266. Typical D subminiature connectors are
manufactured by Cannon, AMP, and Positronic and have 62 pins,
although other D subminiature connectors may be used such as: 5 pin
(power supply with heavy current carrying capability), 9 pin, 26
pin, etc. Furthermore, other D subminiature models may be used such
as combination D-Subminiature connectors which combine coax and
signal contacts. Two D subminiature connectors 266 are incorporated
and held in place in backshell face plate 268 which is connected to
backshell housing 201 via screws 269. Furthermore, an alignment pin
270 is provided, for example in the middle of the two D
subminiature connectors 266 as shown in FIG. 4 and attached by
screws 271.
[0032] Alignment pin 270, in one embodiment, has a curvature to it
which is dependent upon the geometry of backshell 200 and is
constructed such that alignment pin 270 will smoothly rotate for
radial insertion into a receiving hole on face plate 282 of MAU
module 280. The curvature is due to the rotational nature of making
the connection by rotating about the end of deflection arm 220 as
backshell 200 is connected and the electrical connection is made.
Furthermore, face plate 268 of backshell 200 is supplied with a key
272 and the matching MAU module front plate 282 is set up with
matching holes for receiving the key when the proper backshell is
connected to the proper MAU module connections. Therefore,
alignment pin 270 and alignment tab 222 are configured for
simplifying the connection of the backshell 200 to the MAU cabinet,
and key 272 is for reducing the possibility of connecting the wrong
backshell to a pair of connectors on the MAU module front
plate.
[0033] The unused space inside the backshell is advantageous for
providing Deutsch grounding blocks 275 within backshell 200. In an
exemplary embodiment, these grounding blocks comprise Model
#CTJ722E01C-6192, available from Deutsch. These Deutsch grounding
blocks are tied to ground to dissipate magnetic radiation from the
incoming wires 22. The incoming wires 22 in the cable bundles, for
example, are preferably surrounded with a metal mesh overbraid
which is electrically connected to the Deutsch grounding blocks
275. It is advantageous to be able to provide the Deutsch grounding
blocks internally because this improves the long term reliability
and the maintenance of the EMI ground path. For example, an
internal mount removes the ground shields from exposure to agents
in the surrounding environment that could degrade the electrical
path to ground. Furthermore, internal Deutsch grounding blocks
provide for a "clean" installation with no visible wires, etc. In
addition, the "pig tails" associated with the Deutsch grounding
blocks are typically short (to be able to ground the high frequency
noise), and thus it is advantageous to locate the grounding blocks
inside the backshell in close proximity to the wires to be
grounded. An alternative grounding or shielding methodology is, for
example, to use a band clamp near entry holes 210.
[0034] Referring now to FIG. 5, an alternative embodiment is shown
with two entries of cable bundles as in FIG. 4 but with only a
single D subminiature connector containing coax inserts 510. Other
connectors may similarly be used in place of the single D
subminiature connectors such as blind mate coax. Although most of
the parts shown in FIG. 5 are similar to those shown in FIG. 4, a
few differences exist. For example, in place of the Deutsch
grounding blocks, the electromagnetic radiation is grounded using
ring lug terminals 520. These are located near the standard
grommets 530 which are located at the entry to the backshell and
surround the entering cable bundles. In an exemplary embodiment,
ferrite beads 635 filter out high intensity radio frequency. These
ferrite beads 635 are located, for example, on a LAN coax cable. In
other exemplary embodiments, a triax cable may be used instead of a
coax for the LAN. Thus, many types of wiring and protection means
may be well suited for use in alternative embodiments. Furthermore,
an aircraft personality module 540, such as one provided by
Honeywell, Model No. IM-950, may be provided. This aircraft
personality module 540 identifies the electronics, hardware,
software, etc., and is used for splicing, cuts and jumpers, such as
splitting a signal onto two wires. Devices such as aircraft
personality module 540 are conveniently placed inside backshell 200
where space permits.
[0035] With reference to FIG. 6, other embodiments may be employed
consistent with the philosophy of the present discussion, including
configuring the exit of cable bundles 260 in such a manner that
cable bundles 260 exit neither the top 34 nor bottom 36 of
backshell 200, but exit the rear end 32 portion at a predetermined
angle so as to provide efficient packaging and space conservation.
In this embodiment, cable bundles 260 exit end 32 at a location
indicated by reference number 600, and at an angle which
facilitates short turning radiuses for reducing the clearance
distance required in front of MAU cabinet 280 to fit backshell 200
and the immediately protruding cable bundle 260. Cable bundles 260
enter through Tag Ring castellated nut 610 and tag ring jam
nut/cable strain relief 612, manufactured by Glenair. Tag ring 610
provides another means of providing electromagnetic radiation
shielding for incoming cable bundles 260. FIG. 6 also shows a hex
nut head backshell fastener 230 exemplifying that several different
types of fasteners may be used to provide the one mechanical
connection point for the typical integrated backshell 200.
[0036] FIG. 7 shows a further exemplary embodiment with a single D
subminiature connector 510 with coax center contacts 700 provided
in a backshell 200 with a single pair of cable bundles exiting rear
end 32 of backshell 200 at an angle similar to that shown in FIG. 6
but with a space large enough to provide an aircraft personality
module 540 similar to that discussed with reference to FIG. 5. It
is noted that the alignment pin 270 in FIGS. 5 and 7 are located
typically near the mechanical fastener end of the D subminiature
connector, although any suitable location may be selected for
alignment pin 270.
[0037] Integrated backshell 200 shields the cable bundle
connections to MAU cabinet 280 from the environment. The
connections are held together with a clamping force generated by
cam 32 and deflection arm 220, in conjunction with mechanical
fastener 230. This clamping force, and the use of only one
mechanical fastener reduces the chance that vibrations will cause
the wires to loosen and disconnect. The strong housing and the
drainage holes shield the connecting wires from humidity and other
moisture sources, as well as dust and accidental bumps, rubbing, or
other wearing. The grommets and cable bundles provide a firm
connection to the backshell. The use of a deflection arm allows for
expansion and contraction typical when temperatures fluctuate
greatly. However, the deflection arm continually maintains a
clamping force holding the connection together despite temperature
changes and associated material expansion or contraction. Unlike
some screws and many other mechanical fasteners, the deflection arm
can not loosen due to vibrations, or expansion and contraction.
[0038] Integrated backshell 200 also supports multiple D
subminiature connectors as well as other standard connectors.
Providing multiple connectors in a single housing not only makes
efficient use of available space, but makes it faster for an
operator to make the connections, and reduces the opportunity for
connection confusion. For example, a person could connect two or
three D subminiature connectors at a time, and without concern of
getting the cables mixed up and plugged into the wrong slot.
Multiple connectors in one backshell are beneficial to not only
avionics bay connections, but are beneficial for rack-type
equipment and any PCI bus architecture. For example, the present
invention may be used on production floors in connection with
industrial grade equipment.
[0039] In a further exemplary embodiment, backshell connections may
also be made to modular radio cabinet modules and other similar
devices. In this exemplary embodiment, the backshell does not use a
deflection arm for clamping force, but relies on two or more
mechanical jackscrews to create this clamping force. With reference
to FIG. 8, an exemplary exploded view of a mechanical backshell is
shown with many of the features described herein. For example, the
cable bundles in this exemplary embodiment are shown exiting the
back of the backshell at an angle and multiple D subminiature
connectors are provided within the single backshell. In this
embodiment, however, a first fastener 801 and a second fastener 802
are provided for creating a clamping force. The first and second
fasteners are, in one embodiment, jackscrews. It will be
appreciated, however, that other fasteners which can withstand
rigorous vibrations found in aircraft and similar rugged
environments may be substituted.
[0040] With regard to various aspects of the present invention, a
mechanical jackscrew provides a stronger connection than the
standard No. 4 size screws used in typical backshell connections.
The incorporation of one or more D subminiature connectors into a
backshell enables the use of stronger fasteners. The screws 40, of
the D subminiature connectors, are not the source of the force that
maintains the signal connections. Rather, in this embodiment,
fasteners 801 and 802 provide that stronger and more reliable force
to maintain constant engagement of the two mating objects. In
further aspects of the present invention, and unlike D subminiature
screws 40, the choice of fastener is not limited because the
cabinet receiving the fastener is designed to receive the selected
type of fastener. Furthermore, in other embodiments, other
fasteners may be used, such as the deflection arm discussed above
and other fasteners which provide similar strength and
reliability.
[0041] Therefore, the present invention may be useful in
challenging environments subjecting the electrical connections to
rigorous vibrations, humidity extremes, temperature extremes, and
electromagnetic radiation. The device is also useful for PCI bus
architectures and rack-type equipment, and may be found useful in
many industrial applications. An alignment pin on the backshell and
a pin receptacle on the module engage before the connectors to
provide the precise alignment required between the mated connector
pair. As a backshell completes full connector engagement, the jack
screw draws the backshell down against the module surface and
develops the full clamping force of the deflection arm.
[0042] Other variations and modifications of the present invention
will be apparent to those of ordinary skill in the art, and it is
the intent of the appended claims that such variations and
modifications be covered. The particular values and configurations
discussed above can be varied, are cited to illustrate particular
embodiments of the present invention and are not intended to limit
the scope of the invention. It is contemplated that the use of the
present invention can involve components having different
characteristics as long as the principle, the space efficient
backshell that only requires a single mechanical fastener, is
followed.
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