U.S. patent number 3,757,276 [Application Number 05/178,097] was granted by the patent office on 1973-09-04 for connector module.
This patent grant is currently assigned to Bunker Ramo Corporation. Invention is credited to William A. Kailus.
United States Patent |
3,757,276 |
Kailus |
September 4, 1973 |
CONNECTOR MODULE
Abstract
A multi-connector bussing module for aircraft use at
temperatures of 400.degree.-500.degree.F. including a plurality of
two-contact connectors in which a plurality of protected inner
contacts are interconnected by a hollow bus ring and protective
outer contacts in association with the inner contacts are spacially
separated around a hollow interior; an insulative body of
high-temperature plastic extending in juxtaposition over the bus
ring to the protective contacts; and a relatively thin metallic
coating being adherently affixed to the insulative body to provide
an electrically protective shield and also to interconnect the
protective outer contacts of two or more connectors. The assembly
of connectors and bus ring also forms an electrically protective
enclosure around the hollow interior, shielding a plurality of
one-contact connectors with two or more of the contacts being
interconnected by an inner bus ring.
Inventors: |
Kailus; William A. (North
Riverside, IL) |
Assignee: |
Bunker Ramo Corporation (Oak
Brook, IL)
|
Family
ID: |
26873586 |
Appl.
No.: |
05/178,097 |
Filed: |
September 7, 1971 |
Current U.S.
Class: |
439/607.12;
439/886 |
Current CPC
Class: |
H01R
24/40 (20130101); H01R 31/02 (20130101); Y10S
439/933 (20130101); H01R 2103/00 (20130101) |
Current International
Class: |
H01R
13/00 (20060101); H01R 13/646 (20060101); H01R
31/00 (20060101); H01R 31/02 (20060101); H01r
013/34 () |
Field of
Search: |
;339/111,28,29,143,177,170,278C |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Moore; Richard E.
Claims
What is claimed is:
1. A multi-connector module comprising at least one forwardly
disposed two-contact connector, at least one other two-contact
connector in juxtaposition with said forwardly disposed connector,
each connector having first and second contacts being insulatively
separated and each adapted for connection to an external conductor,
means for interconnecting said first contact of at least two of
said connectors, said means having an outer surface, a high
temperature insulative body affixed to at least a portion of said
outer surface and extending to at least two of said second contacts
of said interconnected connectors, and a metallic coating
adherently affixed to at least a portion of said insulative body
and interconnecting said second contacts said insulative body and
said metallic coating remaining intact and adherently affixed at
temperatures of about 400.degree.-500.degree.F.
2. The multi-connector module of claim 1 wherein said insulative
body is of one-piece thermoplastic and said metallic coating
remains affixed to said insulative body at temperatures of about
400.degree.-500.degree.F.
3. The multi-connector module of claim 2 wherein said plastic is an
aromatic polysulfone and said coating is a nickel inner layer on
said plastic and a gold outer layer on at least a portion of the
inner layer.
4. The multi-connector module of claim 1 wherein said insulative
body extends under and provides support for at least a portion of
said second contact.
5. The multi-connector module of claim 4 wherein said second
contact is an extension of said metallic coating.
6. The multi-connector module of claim 1 wherein a plurality of
said forwardly disposed two-contact connectors are arranged in a
parallel pattern, said pattern forming and surrounding a hollow
interior, said insulative body extends on said second contacts
around said hollow interior, and said metallic coating is affixed
over said insulative body and electrically shields said hollow
interior.
7. The multi-connector module of claim 6 which includes an inner
connector assembly disposed within said hollow interior, shielded
by said metallic coating and insulatively separated from said
two-contact connectors.
8. The multi-connector module of claim 6 wherein said insulative
body is of one-piece insulative thermoplastic capable of
withstanding temperatures of about 400.degree.-500.degree.F.
without deformation and said metal coating includes a nickel inner
layer and a gold outer layer on at least a portion of said inner
layer.
9. The connector assembly of claim 6 wherein said interconnecting
means is a metallic ring interposed between at least a portion of
said forwardly disposed and said rearwardly disposed
connectors.
10. A multi-connector module comprising an outer connector assembly
including an outer metallic bus ring having front and rear
surfaces, a plurality of connectors frontwardly disposed around at
least a portion of the front surface of said ring, each of said
connectors including first and second contacts, said ring being
connected to at least a portion of said first contacts, at least
one other connector including first and second contacts connected
to the rear surface of said ring by said first contact and
extending rearwardly therefrom, each of said second contacts
including a metallic sleeve coaxially disposed around each of at
least a portion of said frontwardly and rearwardly disposed first
contacts and insulatively separated from said ring, an insulative
body disposed on said ring and including a section insulatively
separating a portion of each first contact from its associated
metallic sleeve, said insulative body having an outer surface, a
metallic layer affixed to at least a portion of said outer surface
of said insulative body and at least a portion of said metallic
sleeves including those of at least two of said frontwardly
disposed connectors to electrically interconnect said metallic
sleeves, said interconnected metallic sleeves on said frontwardly
disposed connectors being in juxtaposition on said front surface of
said ring to form a hollow interior, and an inner connector
assembly comprising an inner bus ring disposed within said hollow
interior and insulatively separated from said outer ring,
connectors, and metallic coating, said inner ring having front and
rear surfaces, a plurality of forwardly disposed connectors affixed
to the front surface of said inner ring, and at least one
rearwardly disposed connector extending rearwardly from said
ring.
11. The multi-connector module of claim 10 wherein at least one of
said forwardly disposed connectors is insulatively separated from
said outer bus ring and at least one rearwardly disposed connector
is interconnected to said insulatively separated connector.
12. The multi-connector module of claim 10 wherein the metallic
coating is an inner layer of nickel and outer layer of gold on at
least a portion of said inner layer.
13. The multi-connector module of claim 12 wherein said insulative
body is composed of an aromatic polysulfone.
14. The multi-connector module of claim 10 wherein the section of
said insulative body which insulatively separates a portion of said
first contact and metallic sleeve includes an insulative sleeve in
juxtaposition with said metallic sleeve.
15. The multi-connector module of claim 14 wherein said metallic
sleeve is an extension of said metallic coating.
16. The multi-connector of module of claim 10 wherein an insulative
spacer is disposed within said hollow interior and includes a
section positioned against a portion of said front surface of said
outer ring, said spacer including at least one aperture, and each
of said rearwardly disposed connectors on said inner bus ring
positioned in said aperture.
17. The multi-connector module of claim 16 which includes at least
one pair of forwardly disposed and rearwardly disposed connectors
and a second insulative spacer having a front surface bearing
against the rear surface of said inner ring, each of said pair of
connectors including a positioning section between and separating
said first and second spacers.
18. The multi-connector module of claim 15 which includes a
frontwardly positioned insert having apertures in registered
alignment with said metallic sleeves, said forwardly disposed
connectors on said inner ring, and said forwardly disposed contact
on said pair of connectors.
Description
BACKGROUND OF THE INVENTION
In the instrumentation field, multi-connector modules have been
used to interconnect circuits associated with various sensing
elements to instruments for the detection, measurement, or control
of the phenomena being sensed. In the measurement of liquid levels
in an aircraft fuel tank, such modules have been used to
interconnect a plurality of capacitance sensing elements located
within the fuel tank with one or more fuel supply indicating
instruments in the aircraft. Generally, a number of such sensing
elements positioned at spaced-apart locations in the fuel tank are
themselves interconnected or "bussed" together to compensate for
the variations in fuel level produced by changes in the attitude of
the aircraft during flight and thus provide a compensated or
"averaged" indication of the fuel supply.
As the performance requirements of aircraft have been increased,
there has often been an increase in temperatures and temperature
variations to which various components including the
multi-connector modules are exposed. In some instances,
requirements have been set for modules to perform under
temperatures as high as 500.degree.F. and above, together with
temperature variations of from sub-zero to 500.degree.F. Under
these conditions, many modules suffer deterioration, heat
distortion, insulation breakdown, unequal expansion of the various
metallic and non-metallic connector parts and the like. These
effects act to interrupt the individual connections between
connectors and adversely affect the impedance characteristics of
the modules. As an example of the problem, materials in the modules
have an insulative quality which can deteriorate with increasing
temperatures, and at 500.degree.F., sufficient heat can be
generated as to actually cause a breakdown of insulation between
contacts. When some of the insulators are buried within the module,
it is not always apparent on the instruments when signal valves on
the instruments are inaccurate due to deterioration or breakdown of
the insulation.
It is also important that these multi-connector modules be
constructed so as to be of limited weight and size in view of their
use in aircraft. In many instances, the combination of requirements
of performance at high temperatures with reasonable valves of
weight and size can significantly complicate the design of the
modules.
Therefore, it is commercially important that new multi--connector
modules be provided for use on aircraft and that these modules
perform under extreme temperature conditions without being of
excessive weight or size.
SUMMARY
The invention is directed to a high temperature multi-connector
module for use in aircraft at temperatures of about
400.degree.-500.degree. F. and more particularly to a compact
multi-connector molule in which two or more connectors are
internally interconnected or bussed. The module comprises two or
more electrical connectors in juxtaposition with each other, an
insulative body, preferably of one-piece construction formed over
at least a portion of two or more of the connectors, and a metallic
coating adherently affixed to at least a portion of the insulative
body to interconnect the connectors.
More particularly, the insulative body is a high temperature
thermoplastic and preferably an aromatic polysulfone capable of
adherently receiving a thin metallic coating which at temperatures
of about 400.degree.-500.degree. F. does not separate from the
insulative body and does not exhibit silver migration. The module
is particularly useful with two contact connectors having protected
or shielded contacts and in one embodiment comprises a plurality of
two-contact connectors arranged around a bus ring or other means
for interconnecting at least a portion of at least one of the
contacts in each of two or more connectors. An insulative body,
preferably of one-piece construction, is molded around the outer
surface of the bus ring and serves to insulatively separate the
inner contact from the outer contact in each connector while also
insulating the portion of the bus ring adjacent to the inner
contact. The metallic coating is adherently affixed to the outer
surface of the insulative body and extends between two or more of
the outer contacts of the connectors. In a particularly useful
form, the metallic coating serves as a shielding for both the bus
ring and portions of each of the individual connectors. In some
instances, the metallic coating may extend around in spaced
relationship with each of the inner contacts as individual shields
and is adherently affixed to an inner insulative sleeve, preferably
composed of a high-temperature plastic.
Advantageously, the two-contact shielded connectors are disposed on
a bus ring in an outer connector assembly to form a hollow interior
adapted to receive one or more additional assemblies of connectors.
In this arrangement, the outer connector assembly both houses and
shields the inner connectors. Flat, disc-like spacers are also
positioned within the hollow interior and serve to insulatively
separate and mount the connectors. Front and rear inserts with
passages adapted to receive frontwardly and rearwardly disposed
connectors are then positioned around the outer and inner connector
assemblies, spacers, and additional connectors.
One of the advantages of the multi-connector module of the
invention is that it is capable of satisfactory performance at high
temperatures without insulation breakdown. Another advantage is
that the metallic coating is adherently attached to the insulative
body and also capable of performance at these temperatures without
flaking or otherwise becoming separated from the body. A further
advantage is that the metallic coating provides individual
shielding of the outer connectors and also shields the inner
connectors. In addition, the entire assembly provides a housing
containing a plurality of one and two-contact connectors while
being of relatively low weight and size.
DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a perspective view of the components of a module
utilizing the invention.
FIG. 2 is an enlarged front view of the plurality of two-contact
connectors and outer bus ring forming the outer assembly.
FIG. 3 is an enlarged partial side view in cross section of an
individual two-contact connector and associated portion of the bus
ring prior to receiving a metallic coating.
FIG. 4 is an enlarged side sectional view of the module of FIG.
1.
FIG. 5 is an enlarged front sectional view of the module of FIG.
1.
FIG. 6 is a partial side view of another embodiment of the
connector of FIG. 3.
GENERAL DESCRIPTION
The module comprises one or more forwardly disposed two-contact
connectors in juxtaposition with one or more other two-contact
connectors which are usually rearwardly disposed. Each contact is
insulatively separated from the other contact and is adapted for
connection to an external conductor. A bussing ring or other means
is provided for interconnecting an inner or a first contact of two
or more of the connectors and is interposed between the forwardly
disposed and rearwardly disposed connectors. An insulative body,
preferably of a high-temperature insulation, is molded on or
otherwise affixed to at least a portion of the outer surface of the
bussing ring and extends to two or more of the second contacts of
the interconnected connectors.
A thin metallic coating is adherently affixed to at least a portion
of the insulative body and serves to interconnect the second
contact of two or more connectors. The metallic coating is usually
about 100-200 .times. 10.sup..sup.-6 inches although it may range
up to about 1 .times. 10.sup..sup.-6 inches in thickness and can
include two or more layers of shielding metal such as nickel and
gold which in combination are capable of withstanding temperatures
of about 400.degree.-500.degree.F. without separation from the
insulative body and without silver migration at the high
temperatures.
In more detail, the module comprises a plurality of the two-contact
connectors arranged around a bus ring to form an outer connector
assembly having a hollow interior and a plurality of other
connectors on an inner bus ring to form an inner connector
assembly. An insulative body composed of a high temperature
plastic, preferably of one piece, is molded on the outer surface of
the outer bus ring and extends over a portion of a centrally
located contact in the two-contact connector. The metallic coating
is formed over at least a portion of the insulative body and serves
to interconnect outer or second contacts in the two-contact
connector.
The module 10, illustrated in FIGS. 1-5, includes outer connector
ring assembly 11 positioned around inner connector assembly 12,
offset connectors 14 and 16, and spacers 18 and 20, with the
combination being housed between front insert 22 and rear insert
24. In turn, inserts 22 and 24 are housed within an exterior metal
shell 26 of aluminum, illustrated in FIG. 4, and provided with
exterior threaded portion 28 for connection to suitable rear
housing and complimentary connectors (not shown) to those
connectors rearwardly directed in module 10. Exterior metal shell
26 is also provided with interior radial grooves 30 and 31 for
gasket 32 and retainer ring 33 which act with gasket 34 to secure
module 10 within shell 26 and to keep inserts 22 and 24 in snug
engagement. An exterior radial rib 36 is provided on the front end
37 of shell 26 for engagement with a suitable hermetically-sealed
module (not shown) mounted on the wall of an aircraft fuel tank or
other liquid container.
Included in outer connector assembly 11 are outer ring 38, a
plurality of forwardly disposed, closely positioned connectors 39
arranged on the front surface 40 of ring 38 to form hollow interior
41, and one or more rearwardly disposed connectors 42 extending
rearwardly from rear 43 of hollow interior 41 and in juxtaposition
with rear surface 44 of ring 38. Connecting plate 45 (as
illustrated in FIG. 2) serves to interconnect outer ring 38 to rear
connector 42 although in some arrangements, connector 42 can be
conveniently connected directly to rear surface 44. As illustrated,
outer ring 38 includes cutout portion 46 so that one or more of
front connectors 39' can be interconnected to one or more rear
connectors 42' by connecting plate 47 or other suitable means
without being bussed by ring 38.
Each of the connectors 39 and 42 is constructed of beryllium copper
and includes an inner, centrally-located, protected contact 48 and
outer, surrounding, protective contact 49 on connectors 39 and
similar inner and outer contacts 50 and 51 on connectors 42.
Although illustrated in the form of a socket, the inner contact 48
can be shaped as a pin or other form of longitudinally extending
contact. Outer contact 49 is disposed around socket 48 as a second
wire and includes shoulder 52 with front surface 53 which, as
illustrated in FIG. 4, acts as a stop for front insert 22.
Thus, each of the forwardly and rearwardly directed inner contacts
48 and 50 are provided with individual shields 49 and 51 against
magnetic and electrical fields from external sources as well as
from adjacent contacts. In addition, as discussed in more detail
below, connectors 39 are arranged around hollow interior 41 to
provide a shielding effect in respect to inner connector assembly
12 and offset connectors 14 and 16.
Together with connecting plates 45 and 47, outer bus ring 38 serves
as a means for interconnecting contact 48 with one or more other
contacts 48 or contacts 50 or combination thereof. As illustrated,
12 parallel front connectors 39 are arranged in juxtaposition with
bus ring 38, with eleven connectors being connected to ring 38 and
thereby bussed down to one rear connector 42. The remaining front
connector 39' is interconnected by plate 47 to rear connector 42'.
In a similar manner, bus ring 38 can be formed with more than one
cutout portion 46 to provide two or more bus bars for
interconnecting a number of individual groups of connectors 39 and
42.
Outer bus ring 38 is of brass construction and is provided with
outer surface 54 and an insulative body 55 of high-temperature
insulation capable of withstanding temperatures in the order of
400.degree.-500.degree.F. such as an aromatic polysulfone affixed
to at least a portion of surface 54 and extends to two or more of
the outer contacts of connectors 39 and 42 interconnected by bus
ring 38. Preferably, insulative body 55 extends to all of contacts
49 and 51 on outer connector assembly 11.
In FIG. 3, a cross-sectional view of individual two-contact
connector 39 illustrates the manner in which insulative body 55 is
affixed on outer surface 54 of ring 38 and extends under and
provides support for contact 49. Advantageously, body 55 extends
longitudinally with section 56 in juxtaposition with contacts 48
and 49 to insulatively separate and seal the two contacts near bus
ring 38. Inner radial grooves 57 and 58 are provided in contact 49
for sealing and mounting purposes. These and other features of the
individual connectors 39 and 42 are described in my copending
application Ser. No. 177,730 entitled "ELECTRICAL CONNECTOR" and
filed Sept. 3, 1971 which is incorporated herein by reference.
In forming the outer connector assembly 11, a plurality of
two-contact connectors 39 and 42 without insulative body 55 are
positioned around ring 38 to form hollow interior 41. Inner
contacts 48 are swaged or otherwise forced into abutting engagement
in apertures 59 in brass bus ring 38 and connecting plates 45 and
47 are interconnected to bus ring 38 and contact 50. A moldable
high-temperature plastic, and preferably an aromatic polysulfone,
is transferred into the mold and forced between contacts 48 and 49
and contacts 50 and 51 as well as around surfaces 54 and 60 of ring
38 and plates 45 and 47. After the insulated assembly is removed
from the mold, openings 106-107 resulting from mold supporting
surfaces are filled with the plastic forming plugs 108-109.
In the preferred embodiment, the aromatic polysulfone is of the
type available from Minnesota Mining & Manufacturing as
generally described on page 182 of Modern Plastics Encyclopedia,
1970-1971 and has only aromatic groups as the organic portion of
the polymer. This polymer provides a combination of
high-temperature properties, dimensional stability, sealing
characteristics, and platability particularly important for the
high-temperature connector. Mixtures of the aromatic polysulfone
with other high-temperature plastics such as Teflon can also be
utilized for the insulative body.
Next, metallic coating 62 is adherently affixed to outer surface 63
of insulative body 55 and serves to interconnect two or more
contacts 49 and 51. Since insulative body 55 extends over bus ring
38, metallic coating 62 provides a shield over bus ring 38 without
electrically interferring with the internal bussing provided
thereby.
Metallic coating 62 is composed of one or more metals which are
capable of withstanding temperatures of about
400.degree.-500.degree.F. without separation from the underlying
insulative body 55, without flaking associated with silver
migration at these temperatures, and without excessive corrosive
effects. Advantageously, the coating includes an outer corrosion
resistant metallic layer such as gold, nickel or the like and
includes metallic shields for magnetic and electrical fields of
nickel and gold, copper and nickel, iron and gold, and the like. In
the preferred embodiment with an aromatic polysulfone, coating 62
is composed of nickel inner layer 65 on body 55 and a gold outer
layer 66 on at least a portion of the nickel inner layer. The
nickel and gold layers 65 and 66 act in combination as a shield
against both magnetic and electrical fields. In contrast, tests
with a coating composed of copper, silver and gold revealed that at
the high temperatures, portions of the coating could easily be
manually removed.
Advantageously, coating 62 extends over a portion of contacts 49
and 51 and in the preferred embodiment, over the entire surface 67
of the contacts. In the process of forming coating 62, surfaces 63
and 67 of insulative body 55 and contact 49 are treated to adapt
them to adherently receive one or more layers of a metal. Treatment
can include the use of an adhesive on surface 63 and separate
coating steps on plastic surface 63 and metal surface 67. In the
preferred embodiment, plastic surface 63 is treated to receive
electrolessly deposited metal and a nickel layer is deposited in
this manner over surface 63 as well as over at least a portion of
metallic surface 67. The gold is then electroplated over the nickel
inner layer. To avoid coating contact 48, a plug (not shown) is
first inserted around contact 48 and surface 68 of the body 55. As
an alternative, contact 49 (illustrated in FIG. 6) can be formed by
extending metal coating 62 over body 55 surrounding contact 48. In
this instance, body 55 is extended as a plastic sleeve 69 spacially
surrounding and separated from contact 48 to form a socket and in
juxtaposition with coating 62 which forms a metallic sleeve to
serve as the outer contact 49.
Disposed within an outer connector assembly 11 is inner connector
assembly 12, offset connectors 14 and 16 and spacers 18 and 20 (of
aromatic polysulfone). Connector assembly 12 comprises a plurality
of forwardly disposed connectors 70, inner bus ring 71, and one or
more rearwardly disposed connectors 72. In the preferred
embodiment, ten single-contact front connectors 70 extend
frontwardly from front surface 73 of bus ring 71 and are bussed
thereby to rear single-contact connector 72 extending from rear
surface 74 of ring 71. One or more cutout portions 75 in ring 71
permit the extension of separate single-contact front connector 76
Of offset connector 14 while hollow interior 77 of ring assembly 12
provides a passage for single-contact front connector 78 of offset
connector 16. As illustrated, offset connectors 14 and 16 include
flat bars 79 and 80 for interconnecting front and rear connectors
76 and 81 and 78 and 82 respectively and serve to mount connectors
14 and 16 in cavities 83 and 84 of spacer 18 in an arrangement
which resists axial and lateral movement.
Spacer 18 also includes apertures 85, 86, and 87 which serve as
passages for rear connectors 72, 81, and 82 of inner bus ring
assembly 12 and offset connectors 14 and 16. Spacer 18 is a
disc-like polygon with outer concave surfaces 88 to resist radial
movement in respect to outer bus ring assembly 11.
Cavity 89 in spacer 20 serves to position and insulate inner bus
ring assembly 12 from the other metallic components in assembly 10.
Apertures 90, 91, and 92 are provided as passages for rear
connector 72 and front connectors 76 and 78 of offset connectors 14
and 16. Spacer 20 is also shaped as a disc-like polygon with
concave surfaces 93 for resisting radial movement in assembly
10.
In forming assembly 10, outer connector assembly 11 is placed
around the combination of spacer 18, offset connectors 14 and 16,
spacer 20 and inner connector assembly 12. Front and rear inserts
22 and 24 (of aromatic polysulfone) are then positioned on and
around outer assembly 11. Apertures 95 and 96 of front insert 22
are adapted to respectively receive 12 two-contact front connectors
39 of assembly 11 and 12 single-contact connectors 70, 76, and 78
of assembly 12 and offset connectors 14 and 16. Similarly, rear
insert 24 includes apertures 97 and 98 to receive 2 two-contact
connectors 42 of assembly 11 and 3 single-member rear connectors
72, 81, and 82 of assembly 12 and connectors 14 and 16. The entire
combination, as illustrated in FIG. 4, is then housed in shell
26.
IN FIG. 4, a cross-sectional view of the internal bussing
arrangement is illustrated and depicts the arrangement by which 12
two-contact connectors are internally reduced to 2 connectors and
12 single-contact connectors are internally reduced to 3
connectors. As illustrated, front connectors 39 extend through
apertures 95 of front insert 22 and are internally bussed by outer
bus ring 38 to rear connectors 42. In a similar manner, connectors
70 extend through apertures 96 and front insert 22 and are
internally interconnected by inner bus ring 71 to rear connectors
72. Spacers 18 and 20 serve as means for mounting offset connectors
14 and 16 and insulatively separating these connectors from outer
assembly 11 and inner assembly 12. As illustrated, (FIG. 1)
cavities 83--84 and 89 are respectively formed in spacers 18 and 20
and are separated by spacer 20. Spacer 18 is also provided on its
rear surface 99 with rearwardly extending surfaces 100 and 101
(FIG. 4) for positioning of the spacer in rear insert 24. Rear
insert 24 is also provided with forward extension 102 which fits in
complimentary groove 103 in outer assembly 11 and spacer 18.
FIG. 5 further illustrates the relative positions of front
connectors 39, 70, and 76, and 78. The front view of exterior shell
26 is also illustrated together with the projections 104 and 105
for keying assembly 10 in shell 26 and for a mating housing (not
shown) containing complimentary connectors into shell 26. Cutaway
portions of the assembly 10 also reveal flat bars 79 and 80 of
offset connectors 14 and 16 within the assembly.
The foregoing description of the present invention is only
illustrative of an exemplary form which the invention may take.
Still other modifications and variations will suggest themselves to
persons skilled in the art. It is intended, therefore, that the
foregoing detailed description be considered as exemplary only and
that the scope of the invention be ascertained from the following
claims.
* * * * *