Note: Descriptions are shown in the official language in which they were submitted.
BACKGROUND
An RG coaxial cable (Fig.1~ consists of a centrally located
center conductor and typically five concentric layers The center
conductor 1 is oF either copper-clad steel or solid copper
material, It is surrounded by a dielectric layer 2 which is
typically comprised of cellular polyethylene. A thin layer of
aluminum foil 3 is wrapped about the dialectric, with the purpose
of providing electrical grounding and RFI shielding, Additional
groundin~ is provided by a system of braid;ng 4 which surrounds the
aluminum foil. The amount of braiding o~ten varias amongst cables
and is de~cribed as a percentage o~ coverage, for examplè, 40%,
60%, 95%, On occasion, double-shielding is encountered such that
there is an additional foil and braiding layer, which acts as a
protection against signal leakage and electromagnetic interference.
A seeond layer 5 o~ typically polyethelene or PYC material acts as
the outside protective jacket.
Connectors for the cable groups defined by the above
description are generally used at cable interfaces with equipment,
The cable is prepared by trimming as described by Fig.1. Th
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center conductor 1 is exposed to a length of typically l/4 inch
and the cable outer layer 5 is further trimmed back by typically
1/4 inch. The braiding system 4 is then pulled back over the outer
layer as shown to expose the aluminum foil 3. The purpose of this
operation is to allow a continuous ground during the subsequent
connector installation, as it is almost always the case that an
electrically conductive sleeve is fitted between the aluminum foil
layer 3 and the braiding 4. The exposure of the center conductor
1, which carries electrical signals, allows it to contact with
equipment which is designed to accept the center.
The difficulties encountered at connector interfaces extend
beyond simply the continuation of a signal. It is required ~hat
the connector be able to grasp the cable with enough strength such
that considerable tension on the cable will not cause the cable to
pull free of the connector. Also, cables are often expossd to
severe environmental conditions and so, the connactor must be
sealed against water and moisture ingress. As well, it must be
protected against the infiltration of external signals. These are
problems which must be resolved by the current design.
In the past, connectors have typically addressed only some of
the above requirements. The mechanical retention of the cable has
been a priority and this was achieved by simply crimping an annular
sleeve over the cable outer lay~r by means of a hex crimpA While
effective mechanically, crimping in this manner allows water to
~r~ely enter the system because complete closure is absent at the
points of the hex. Likewise, external signals can penetrate
through and disrupt the signal. As well, due to the nature of the
previously accepted design, there are several o-ther regions within
the connector where corruption of the signal can originate. As the
requirements of systems, and in particular connector interfaces,
has been upgraded, it becomes imperative to design a connector of
higher quality which can meet higher standards.
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OBJECT~VES OF THE CURR~NT INV~NTION
In order for a design to be effective, it must be marketable
and it must be able to meet its technical r0quirements.
Therefore, it ~ust be easy to install and it must meet its
requirements in as simple a manner as possible.
One objective of the current invention is that it be craft
sensitive, that is, it must be easy to install, it must be
economical, and it must be ef~ective. It was required that the
device is presented as a single piece, albeit several parts
assembled as one piece, to guard against the possibilty that during
installation problems may occur as minute pieces are easily
misplaced. Further, in order to facilitate the connector
installation, it was preferable to design a connector in which no
special tooling is required in order to achieve a connection, which
is the case with several prior art inventions. Therefore, the
current invention is installed with the use of a standard hex
wrench.
The technical objectives are also achieved by the current
invention. The connector is able to grasp the cable with enough
strength that the pullout force which is needed in order to detach
the cable exceeds the design capabilities of the cable, that is,
any tension failure is traced back to the cable rather than the
connector. The device achieves sealiny at both the front and the
back end of the connector, which are the two possible points of
liquid ingress.
DESCRIPTION OF THE DRAWINGS
Five drawings are presented as a reference for the complete
description of the current invention, which follows thereafter.
FIG. 1 illustrates a typical RG-type cable, as well as the
trimming preparation required prior to connector installation.
FIG. 2 describes the configuration of the connector, as well
as the cable position immediately after its installation.
FIG. 3 details the form and features of each of the three
components integral to this invention.
FIG. ~ describes the mechanisms employed which allow the
current invention to successfully meet its objectives, as the
assembly of FIG. 2 is mated with an F-type female interface.
Fig. 5 is a series of pictorial illustrations which describe
the form and features of all components integral to the connector.
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23~
SlJMMARY OF THE CURRENT INVENTION
Referring to Fig. 2 and Figs. 3(a)/3(b)/3(c), the components
which comprise the current invention are as follows: the body oF
the connector 40, an internal sleeve ~0, an internal clamping
device 60, a front seal 80~ and a rear seal 90.
Fig. 2 describes the connector in its assembled configuration.
Also shown is the installation of the cable onto the given devica.
It must be noted that all the internal parts of the connector are
loose in relation to each other, that is, all parts are "floating",
which is a feature which contri`butes to the overall versatility of
the current invention. Although "floating", both the sleeve and
the clamping device are assembled in such a way that they are
locked inside the body. A certain amount of lateral movement is
allowed to the sleeve and clamp along the axis of the connector.
During the installation of the device to a mating interface, this
lateral movement is gradually eliminated as all the internal
components, including the cable are locked in position as the
threads 41 of the body are screwed onto the threads of the mating
part 200 (see Fig. 4). Fig. 4 describes the configuration of the
system after mating, 1n particular the distortions caused in
certain components which allows the sealing and the clamping of the
cable system.
A prepared cable is joined to the connector as follows: the
aluminum foil 3 slips within the sleeve 20 and the cable is pushed
forward (leftward in relation to the diagrams) until the cable
dielectric 2 meets with the lip 22 of the sleeve, which acts as a
stop in this regard. Also, as the cable is pushed forward, the
braid 4 and the outer layer 5 of the cable~ override the sleeve,
positioning itself loosely under the teeth ~2 of the clamp. As
well, a section of the cable outer layer which does not override
the sleeve is positioned loosely under the rear seal 90. During
this cable installation, the positions of the internal clamp an~
sleeve are at the most forward positions (left-most). A stop ~0
on the body defines the position of the clamp whil~ a stop 6~ on
the clamp defines the position of the sleeve
It is noted that while the installation of the cable is a
smooth operation, its subtractien from the connector is not. Due
to the nature of the current invention, any attempt to remove the
cable by pulling it back (to the right) causes the sealing and
clamping mechanisms (describad further on) to come into play~
Therefore there is a resistance to the cable easily detaching
itself from the connector. This inherent cable retention acts as
a safeguard to certain installation difficulties. The complete
sealing is then achieved by mating with an interface.
Referring to Fig. 4 for the mated configuration, sealing is
achieved as the seal rings 80 and 90 are compressed while clamping
page 4
is achieved as the clamp ring 60 closes upon the cable. As the
mating part 200 is threaded into the body 100, it pushes the sleeve
20 backward (to the right). In turn, the clamp is also pushed
backward and while so moving, its toothed end meets with a ridge
47 on the body's internal surface, which causes the clamp to close.
The -Final position o-f the clamp and sleeve is determined by a stop
43 on the body's internal surface. As diagrammed, the front seal
~0 is compressed betwserl the mating part, the sleeve and the body,
which affords a reliable seal. The rear sealing is achieved when
the cable outer layer lying below the rear seal 90 is expanded by
the repositioning of the sleeve after mating such that it has
extended beyond the seal. As a result, the cable outer layer
compresses the seal.
DESCRIPTION OF THE INDIVIDUAL COMP~NENTS
Referring to Figures 3(a), 3(b), 3(c), for the body, sleeve
and clamp, this section des-ribes the connector components in
detail.
The body ~0 is machined from typically 7/16" hexagonal brass
material. There are three internal undercuts and a threaded
forward portion 41. The thread is a standard for the industry as
all mating parts are designed with 3/8-32 threading. The first
undercut 42 houses the front seal, the second undercut 45 encloses
the clamp, and the third undercut 48 is designed to hold the rear
seal. The ridge 47 controls the amount of compression endured by
the clamp. The ridge 49 is of a diameter such that the cable can
easily pass through into the connector. A stop 43 determines the
final position of the sleeve and another stop 50 of the clamp
undercut, deter~ines the initial position of the clamp. The
external surface is shaped in such a manner that the connector can
be easily grasped and held securely. A ridged area 5~ açts as a
grip for the installer while the installer is pushing the cable
into the connector.
The sleeve 20 is typically machined ~rom round brass material.
Its internal bore 23 is designed to slip oYer the cable aluminum
foil and a stop 22 determines the final position of the cable.
Three ridges 24 on the back end of the sleeve expand the cable
outer layer and also are designed to prevent pullout of the cable.
The surface 21 acts as a seat to the front seal and a stop 28 meets
with a corresponding stop ~3 on the body to determine the final
position of all the internal components. The surface 27 acts as
a fitting for the clamp, while a ridge 26 prevents the clamp from
detaching itself from the sleeve.
The clamp 60 is mashined from round plastic of a durable and
resilient material, typically delrin. It is slotted in an unusual
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manner, as shown, with a through slot 69 and a partial slot 67.
Teeth 62 grip the cable outer layer. The internal surface 65 fits
in position with a corresponding surface on the sleeve and the
surface 64 fits loosely under an internal ridge 44 on the body. The
through slot is necessary to allow the clamp to become smallar in
diameter as it is assembled into position within an undercut in the
body. Therefore, this slot serves as an assembly requirement~ The
through slot also allows the clamp to close at the toothed end as
the connector is mated. The partial slot at the rear end of the
clamp allows it to close further at that section, which accomodates
a need to achieve a high level of cable gripping.
These items are shown pictorially by Fig. 5. The assembly
process is described following. All internal parts are fitted
sequentially into the connector body. The rear seal is to be
positioned first within its slot. Following is the clamp, which
is slotted to allow it to slip through a smaller diameter to reach
its desired location within an undercut. Next, the sleeve is
press-fitted into the clamp as the ridge 26 causes the slotted
clamp to expand and then contract after the ridge has passed
through to position 66 of the clamp. The shape of the ridge and
the diameters of the clamp, sleeve and body are such that it is
impossible for the sleeve to disengage from the clamp. Finally,
the front seal is loosely seated on the sleeve and within an
undercut insida the body.
ADDITIONAL FEATURES OF THE CURR~NT INVENTION
The following notes describe several additional features which
are inherent to this connector design:
The rear seal is achieved when the cable is expanded into the
space occupied by the seal during the installation of the connector
with a mating component~ This feature is unusual in that in almost
all previous designs, the seal is designed to compress into space
which is occupied by the cable.
Sealing and retention mechanisms are addressed individually
with two independent internal components, a seal and a clamp. As
a result, the weaknesses of either component does not compound with
the weaknesses of the other component. The seal serves that
function alone, and likewise the clamp serves that function alone.
Prior art desi`gns have attempted to combine these two functions
with a single component. The current invention realizes that
sealing is best achieved with a spongy material which is
necessarily too weak to achieve a strong mechanical grip on a
cable. Conversely, gripping is best achieved with a hard plastic
material ~hich is often unable to seal as effectively as spongy
material.
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While threading onto the mating component, the cable remains
loose within the connector until typically the final thread turn,
when the clamp mechanism comes into effect. The turning prior to
the final turn is necessary to take up the slackness which is a~
fcature of the current design. Although loose prior to this stage,
there is a cable retention mechanism which is inherent to the
current invention which has been described previously.
