IE20030313U1 - An improved cable joint closure system - Google Patents
An improved cable joint closure systemInfo
- Publication number
- IE20030313U1 IE20030313U1 IE2003/0313A IE20030313A IE20030313U1 IE 20030313 U1 IE20030313 U1 IE 20030313U1 IE 2003/0313 A IE2003/0313 A IE 2003/0313A IE 20030313 A IE20030313 A IE 20030313A IE 20030313 U1 IE20030313 U1 IE 20030313U1
- Authority
- IE
- Ireland
- Prior art keywords
- base unit
- unit
- cover unit
- closure
- cable joint
- Prior art date
Links
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Abstract
ABSTRACT A telecommunication cable joint closure comprising a cover unit, a base unit, a sealing means and a securing collar. The cover unit is sealably mountable on the base unit to form ajoint line. A sealing means is locatable between the cover unit and the base unit vtherein the securing collar is sealably mountable over thejoint line. The collar is adapted so that in use the collar is mounted over thejoint line so that the collar co—opei*ates with the seal means to substantially fully form a seal about the cover unit and the base unit.
Description
This present invention relates to a cable joint closure system and more particularly to a
cable joint closure system for use in the telecommunications industry.
A telecommunications distribution network system can be divided into two distinct
sections, a pressurised section and a non—pressurised section. The non—pressurised section
is also known as an access network. Cable joint closures or ready access closures are used
throughout the access network connecting main telecommunications cables to individual
cables that are in turn connected to places of business, residence and so forth. Commonly,
a closure comprises a dome-shaped cover unit which is mountable over a base unit. A main
telecommunication cable enters the closure through an opening within the base unit and
connects to a number of individual cables within the dome cover. The individual cables
exit the closure via alternate openings on the base unit. Most of these closures are stored in
ready access junctions beneath the ground. The openings in the base unit and the joint line
between the dome cover and the base unit are sealed to prevent water ingress. Generally a
water-resistant sealant is used to seal the openings in the base unit and an ‘O ring’ is used
to seal the junction between the dome cover and base unit.
Resin type cable joint closures were introduced in the late l980’s, however there were
many problems inherent with this type of closure. Primarily, the plastic materials used to
form the base unit were brittle materials that cracked or shattered when a drill was used to
form the openings for the cables. This problem was solved by using a heated conical iron
to pierce the base unit thus forming the openings. Secondly, the sealant used to seal the
openings in the base unit was a resin type sealant that had high curing temperatures. The
plastic materials of the base unit were unable to withstand this temperature. The base unit
became distorted as heat was generated. A solution to this problem was to use
polycarbonate inserts preventing the resin sealant having direct contact with the plastic
material. The use of inserts coupled with the necessity to use a heated conical iron led to
even more problems. It became necessary to use the iron to pierce both the base unit and
the polycarbonate inserts. It was important when performing this action to create a seal
between the base unit and the polycarbonate insert to prevent water ingress between the
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two layers. It was also essential to treat the coating on the cables for example by etching to
ensure that the resin adhered to the cables forming a proper seal. Sealing the closure
became a laborious time consuming task requiring great skill. In practice the closures in
the access network rarely mirrored the results achieved in the laboratory, this resulted in
the majority of closures sealed in this manner leaking.
Heat shrink materials were introduced as a substitute to resin for sealing the closures. The
base unit material was changed to a glass fibre composite compound that had knock out
ports to facilitate easy cable entry. Whilst heat shrink materials provided an easy solution
for sealing closures, they required the use of a naked flame. This was unacceptable as
common practice as there was always a danger of gas leakage in the underground
junctions.
A further closure system was developed by Raychem, now Tyco comprising a hinged
closure using gel tapes to seal the closure. The method of securing the base unit and cover
unit of this closure required a person to tighten a plurality of bolts. Very often one or more
bolts were inadvertently left untightened enabling water to enter the joint. Gel tapes could
not be reused as they collected dirt easily, therefore if the closure was re-entered new gel
tape had to be provided each time.
Other systems such as mechanical systems proved too costly and did not provide cable
flexibility for use. Closures incorporating cable glands were bulky and were unable to
manage varying cable diameters. Grommet systems could not adapt to correctly seal
flexible cables.
The majority of cable joint closures in use in Ireland are resin type cable joint closures. It
is estimated that on average approximately 30% to 50% or possibly greater of the closures
in an access network are leaking. This is especially prevalent if the closures are used in a
particularly wet area. In these conditions the underground access junction could easily fill
with water. Water then enters the sealed closure by capillary action through any opening
on the joint closure.
A telecommunication access network that has a water leakage problem suffers from a
number of problems which are manifested as follows:
Contacts and Earth connection shorting (Loss of Phone lines),
Dis and inter Dis pairs (paired telephone lines, this is due to water causing
corrosion of copper wires by electrolysis over long periods of time),
Noisy Pairs (a buzzing noise is heard on the line when in use),
Changed Pairs (other people’s conversations can be heard in the background when
using the phone).
Where a large number of line faults are reported, it is possible that all the faults stem from
the same closure thereby leading to a false recording of the level of faults within a
network. Repairing a fault within a closure does not necessarily mean that the problem is
solved or that a repeat fault on the same cable will not occur. Areas where upgrade work
was completed and the work was subsequently visually checked showed that 30% of the
closures were leaking within a short period of time.
EP 0546267 discloses a toggle type fastener for closing a cable sleeve, particularly
telecommunication cables. This fastener was developed for split cover type pressurised
joints and is unsuitable for use with dome shaped cover joints which are in the
unpressurised section of the network system. This type of fastener simply secures the
components of the split cover joint together and does not form a seal.
US 6,025,561 discloses a clamping member in the form of a split ring. When in use the
clamping member is placed about the flanges of a two-part cable splice closure thereby
preventing axial movement. There are no securing means on the clamping member
therefore the clamping member is unable to exert sufficient pressure on the joint to prevent
and/or stop water ingress.
Therefore currently used telecommunications cable joint closures do not adequately
prevent water ingress into the interior of the joint closure.
It is the object of the present invention to seek to alleviate the aforementioned problems.
Accordingly, the present invention provides a telecommunication cable joint closure
comprising a cover unit, a base unit, a sealing means and a securing collar, the cover unit
being sealably mountable on the base unit to form a joint line, a seal means locatable
between the cover unit and the base unit wherein the securing collar is sealably mountable
over the joint line and the collar being adapted so that in use the collar is mounted over the
joint line so that the collar cooperates with the seal means to substantially fully form a seal
about the cover unit and the base unit.
Advantageously the cover unit of the telecommunication cable joint closure comprises a
hollow generally cylindrical shape. Ideally the cover unit is sealed at a first end and open
at a second end, the sealed end of the cover unit preferably having a generally curved
surface forming a dome shaped seal. Advantageously, the open end of the cover unit has a
radially projecting flange where the flange projects outwards. It is preferable for the sealed
end of the cover unit, the cover unit and the radially projecting flange to be formed as a
single unit. Ideally the cover unit is made from a blend of Polycarbonate and Acrylonitrile-
Butadiene-Styrene (ABS) material. Advantageously, this material has been specified as
suitable by British Telecom, having the durability to withstand extremes in weather over
the lifetime of the joint. The invention is not limited to this material and any suitable
material known to a person skilled in the art can be used.
Advantageously, the base unit of the telecommunication cable joint closure also comprises
a generally hollow cylindrical shape. Ideally, the base unit is sealed at a first end and open
at a second end and preferably, the sealed end of the base unit has a flat surface enabling
the base unit to stand on the sealed end when desired. Advantageously, the base unit of the
telecommunication cable joint closure has a radially projecting flange.
Ideally the diameter of the radially projecting flange of the base unit is equivalent to the
diameter of the radially projecting flange of the cover unit.
Advantageously when assembling for use and when in use the cylindrical surface of the
base unit intermediate the open end of the base unit and the radially projecting flange
inserts into the open end of the cover unit, so that the cover unit is mounted over the base
unit and the projecting flanges of both the cover unit and the base unit lie in a juxtaposed
position. Advantageously when the base unit inserts into the open end of the cover unit,
there is a degree of overlap between the cylindrical surfaces of the base unit and the cover
unit. Ideally the radially projecting flanges of both the base unit and the cover unit provide
a stop means that prevent the base unit from inserting fully into the cover unit.
Advantageously the degree of overlap of the cylindrical surfaces of the base unit and cover
unit is determined by the position of the radially projecting flange on the base unit.
Advantageously, the radially projecting flange on the base unit can be positioned at any
required distance from the open end of the base unit. Ideally in the preferred embodiment
of the invention the radially projecting flange of the base unit is positioned approximately
mm from the open end of the base. Advantageously, the flange is positioned
intermediate the open and sealed ends of the base unit.
Ideally the sealing means comprises an O—ring which is positioned intermediate the
projecting flanges of the cover unit and the base unit. Preferably the upper surface of the
radially projecting flange of the base unit has a recess for receiving the O—ring, the upper
surface being defined as the surface closest to the open end of the base unit.
Advantageously the recess is of insufficient depth to fully accommodate the O—ring it
merely acts as a receiving means for the O-ring. Conveniently in the preferred
embodiment of the invention the recess has a depth of approximately 1.5 mm..
Advantageously the interior surface of the cover unit that is in contact with the O—ring is
engineered to exert maximum pressure on an increased surface area of the O-ring to form a
tighter water/air seal than is commonly found on cable joint closures. Ideally this effect is
achieved by tapering the area of the interior surface of the cover unit in contact with the O-
ring. Ideally the area of the cover unit in contact with the O—ring is the interior surface of
the open end of the cover unit wherein the radially projecting flange projects from the
cylindrical side walls of the cover unit.
Ideally once the cable joint closure is assembled, the closure is further secured by means of
a collar assembly. Advantageously the collar is designed to exert maximum pressure on
the joint line hence the O-ring, maximising seal integrity.
Ideally the collar assembly comprises two semi-circular collar pieces, which when fitted
together form a circular unit, and a fastening mechanism. Advantageously the collar
pieces are generally u-shaped in cross—secti0n Ideally the collar assembly fits securely
over the radially projecting flanges of the cover unit and base unit when the cable joint
closure is assembled. Advantageously, when the collar pieces are fitted together to form
the circular collar assembly, the u-shaped collar pieces are fitted such that the closed end of
the u-shape comprises the outer edge of the circular collar assembly. The outer edge of the
circular collar assembly is defined as the surface of the collar assembly remote the flanges
of the cover unit and base unit when the collar assembly is fitted over both flanges.
Advantageously the two collar pieces are hinged together at a first point using a simple
hinge and securing pin mechanism. Advantageously once hinged the two collar pieces are
secured together using the fastening mechanism at a second point, which is diametrically
opposite the first point. Advantageously the fastening mechanism comprises a curved bar,
a curved u-shaped grip and a securing pin. Advantageously the curved bar comprises a
generally three dimensional rectangular shape and has an opening at each end for securing
the bar. Ideally each opening is circular. Advantageously the curved u-shaped grip has a
generally curved wedge shape, wherein the u-shape section is formed at the thicker end of
the wedge and the grip section is formed at the thinner end of the wedge. Advantageously
there are two pairs of openings for securing the u-shaped grip. Ideally each opening within
a pair is circular and is positioned opposite the other opening in a pair on the arms of the u-
shape section. Ideally the curved bar inserts into the centre of the u-shape section.
Advantageously the bar and u-shaped grip are secured together by passing a securing pin
through a pair of openings on the u-shaped grip and the opening on the end of the curved
bar. Preferably the pair of openings remote the grip of the u-shaped grip are used to secure
the curved bar.
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Ideally each collar piece has a pair of ring attachments remote the hinged attachment point
which, project radially from the external surface of the closed end of the u—shaped collar
piece remote the closure when the collar assembly is fitted over the joint line. Ideally each
pair of ring attachments do not directly connect with the other pair of ring attachments on
the other collar piece. Advantageously there is a space positioned intermediate each ring
attachment within a pair. Preferably each ring attachment within a pair is positioned
directly in line with the other such that the central opening on each ring attachment is in
line with the other in its pair.
Advantageously a third ring attachment is also positioned radially projecting from the
external surface of the closed end of the u-shape on each collar piece. Ideally the third
ring attachment is positioned at a distance from each pair of ring attachments on each
collar piece and in line with the space positioned intermediate each ring attachment within
a pair.
Ideally the unattached end of the curved bar (the opposite end being attached to the curved
u—shaped grip) is positioned in the space intermediate a first pair of ring attachments on a
first collar piece. Advantageously a securing screw placed through the openings on each
ring attachment and the opening on the curved bar secures the curved bar in position.
Advantageously the curved bar is sufficiently curved that it passes through the space
intermediate a second pair of ring attachments on the second collar piece.
Advantageously the arms of the u—shaped grip are positioned the same distance apart as the
rings of the second ring attachment. Ideally the ends of the arms of the u—shaped grip
remote the grip section are in contact with the rings of the second ring attachment.
Advantageously the end of arms of the u—shaped grip in contact with the ring attachments
are curved to facilitate movement of the u—shaped grip as it moves about the ring
attachments thus clamping the fastening device. As the u—shaped grip moves about the
ring attachment towards the cable joint closure the collar assembly is tightened to a pre-
assigned tension providing a further means of securing the cable joint closure against water
and air. Advantageously once the u—shaped grip has secured the two collar pieces a
securing pin is passed through the openings nearest the grip of the u—shaped device and the
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third ring attachment to prevent the fastening mechanism from opening without
interference.
It is preferable for the interior of the hollow base unit to be divided into a plurality of
chambers. Preferably the chambers are formed by positioning a series of struts within the
hollow base unit where the struts are perpendicularly connected to the interior flat surface
of the sealed end of the base unit. Advantageously, the struts are also connected to the
interior surfaces of the side walls of the base unit. Ideally, the plurality of chambers
comprise a central main chamber encircled by a plurality of minor chambers.
Advantageously, the main telecommunication cable is housed in the main chamber of the
base unit of the cable joint closure. Ideally, the main telecommunication cable enters the
main chamber through an opening in the sealed end of the base unit. Preferably the
opening in the sealed end of the base unit is only formed on site when the cable joint
closure is being brought into use. Ideally there are pre-assigned hole markers on the sealed
end of the base unit to direct and guide when forming the opening.
Ideally the base unit is made as a single unit with the struts formed integrally within the
base unit. Advantageously, this can be achieved by blow-moulding the base unit. Ideally a
blend of Polycarbonate and ABS material is used to form the base unit, alternative suitable
materials know to a person skilled in the art can also be used. The design of the present
invention has the advantage that there is no need to incorporate a polycarbonate insert into
the base unit. Whereas polycarbonate inserts commonly have to be used in conventional
resin type cable joint closures.
Advantageously in a second embodiment of the telecommunications cable joint closure the
base unit is readily adapted to accommodate telecommunication cables that are already in
use in a ready access network, that is where a main telecommunication cable is already
connected to a plurality of individual cables.
Advantageously, the sealed end of the base unit comprises a removable seal. Ideally the
removeable seal has a plurality of openings. Ideally, the openings have different
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diameters to accommodate large diameter main cables and small diameter individual
cables. Advantageously a split-line radiates from each opening to the edge of the seal
thereby enabling access to each opening. Ideally the seal is formed from a pliable material
such as a rubber material thereby enabling a person to manipulate the seal around the
telecommunication cables thereby inserting cables into the openings on the seal.
Advantageously the seal inserts into the base unit at the first end of the base unit thereby
forming the sealed end of the base unit. Advantageously the first end of the base unit has a
gripping means for securing the seal in position. Preferably the gripping means comprises
a circular ring which is generally u-shaped in cross-section. Advantageously the open end
of the u—shape faces the interior of the hollow cylindrical shape of the base unit. Ideally
the edges of the seal insert into the open end of the u-shaped circular ring and are held
securely in position.
Advantageously in a further embodiment of the telecommunications cable joint closure the
base unit comprises two sections, a first section containing a plurality of chambers and the
second comprising a removeable seal. Ideally the first section comprises a plurality of
chambers containing a main chamber and minor chambers. Conveniently the chambers are
formed either integrally with the base unit or using struts. Advantageously in this
embodiment the main chamber is not encircled by minor chambers. Conveniently the
removeable seal contains openings with cuts as previously described. Advantageously, the
removeable seal is manipulated around cables and is inserted and secured into the base unit
as previously described.
Conveniently the open end of the base unit remains the same in all embodiments thereby
enabling the base unit to be inserted into the cover unit using the flange as a stop means as
described above. Advantageously the base unit of each embodiment and cover unit are
sealed and further secured by means of an O-ring and collar assembly.
Advantageously the cable joint closure optionally includes a sleeve extension, a mounting
bracket and pin mechanism. Optionally the sleeve extension can be moulded at one part of
the cylindrical wall surface on the base unit. Advantageously the sleeve extension is
generally cuboid in shape. Ideally there is an opening on each side of the cuboid.
Preferably each opening on opposing sides is positioned directly opposite each other.
Advantageously the mounting bracket comprises a generally cuboid receiving means
mounted on a securing unit, wherein the securing unit is a panel with either a flat or curved
surface with openings for screws where the securing unit is removeably mountable on
either a pole or a wall. Ideally the front surface of the cuboid receiving means is removed,
wherein the front surface of the receiving means is defined as the surface remote the
securing panel. Ideally each side surface of the receiving means have openings.
Conveniently each opening is positioned directly opposite the opening on the opposite
side. Advantageously the sleeve extension fits into the receiving means of the mounting
bracket, such that the openings on the receiving means and sleeve extension correlate.
Ideally a securing pin is passed through the openings on the surfaces of the receiving
means and sleeve extension securing the mounting bracket and cable joint closure together.
Ideally the sleeve extension can be formed integrally with the base unit.
Advantageously the securing pin used to secure both the fastening device and the mounting
bracket comprises a cylindrical pin having a grip at one end and a pointed tip at the other.
Ideally the diameter of the pointed tip is slightly greater than that of the cylindrical body of
the pin. Ideally a central portion of the tip is removed allowing the tip of the pin to
compress as it passes through openings and expand once through the opening.
Advantageously the openings have a diameter that is narrower than the diameter of the tip
of the pin but equivalent to diameter of the cylindrical body of the pin.
Advantageously the cable joint closure optionally includes a handle on the top exterior
surface of the hollow dome cover unit, wherein the top surface is defined as the surface of
the cover unit that is remote the base unit. Advantageously inclusion of the handle enables
the cable joint closure to be suspended in an underground access junction helping to
prevent unnecessary exposure to water.
Advantageously the cable joint closure optionally includes an adaptor which is mountable
on the sleeve extension. Ideally the adaptor comprises a generally cuboid receiving means
mounted on a generally cuboid insertion means. Advantageously the front surface of the
,;
receiving means is removed, wherein the front surface of the receiving means is defined as
the surface remote the insertion means. Ideally there are diametrically opposite openings
positioned on a pair of opposing surfaces on the receiving means. Preferably the front
surface of the insertion means is removed, wherein the front surface of the insertion means
is defined as the surface nearest the receiving means. Advantageously there are
diametrically opposite openings positioned on each pair of opposing side surfaces on the
insertion means, wherein the side surfaces are defined as the surfaces nearest the front
surface of the insertion means. Conveniently the adaptor is readily mounted on cable
bearer brackets by inserting the receiving means into the cable bearer brackets and
preferably securing the adapter by inserting a securing pin through the openings on a cable
bearer bracket and the insertion means of the adaptor. The sleeve extension of the cable
joint closure inserts into the receiving means of the adaptor and is secured by passing a
securing pin through the openings as previously described.
Advantageously the cable joint closure includes markings on the top interior surface of the
hollow dome cover unit that enable a user to identify the manufacturer, batch number and
date of installation of the closure system.
Conveniently the individual components of the cable joint closure system with the
exception of the sealing means are secured together by means of a polyester cord.
Advantageously a new cable joint closure has no holes in the base, therefore it is necessary
to drill a hole or holes in the chambers of the base unit using a stepped conical drill bit to
facilitate the cables. Ideally the main telecommunications cable is inserted into the main
central chamber. The main telecommunications cable is then connected to the individual
ancillary cables which exit the joint through the minor chambers encircling the main
chamber. Advantageously more than one cable can be installed in each chamber. Once the
openings have been made it is necessary to seal around them to ensure no water enters the
cable joint closure. Ideally where more than one cable is installed in a chamber it is
preferably to maintain a minimum gap of 5mm between the cables and/or the chamber
walls to ensure that a good seal is achieved. Conveniently the interior surfaces of the base
‘M30515
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unit and the surfaces of the chambers are etched to facilitate the formation of a good seal
between the sealant and the base unit.
It is preferable to clean the cables and interior of the cable joint closure in order to remove
grease and dirt that may prevent a good seal forming. Advantageously either wet or dry
isoparoffin (PF) wipes are used. Advantageously the cables‘ do not need to be prepared as
necessary with resin type closures.
Advantageously the cable joint closure is used in conjunction with a sealant having a low
curing temperature to prevent water ingress into the closure system by capillary action
along the wires, wherein the polyurethane sealant is applied to the chambers with openings
in the base unit of the cable joint closure. Ideally the sealant used has a maximum curing
temperature in the range of 40°C to 50°C. Conveniently the apparatus of the invention can
be used together with Dexbond TM sealant, a two-part polyurethane sealant.
Preferably the polyurethane sealant is applied using the following procedure:
(a) cleaning the area of the closure to be sealed;
(b) sealing the cleaned area of the closure;
(c) attaching a pressure testing apparatus to the sealed joint closure;
(d) applying leak detection fluid; and
(e) activating the pressure testing apparatus to test the closure for leaks.
Advantageously putty tape is placed around the cables entering and exiting the base of the
cable joint closure. Preferably the putty tape is placed on the exterior surface of the flat
surface of the base unit remote the chambers. Ideally the putty tape acts as a barrier when
applying the sealant. Advantageously the putty tape does not have to be removed it can
remain in position thus further preventing water ingress into the chamber.
Advantageously, the pressure testing apparatus used to test the cable joint closure
comprises a hollow housing unit, which is adapted to fit over and seal with the base of a
cable joint closure and inlet valve, wherein a pump is attachable to the inlet valve.
E 030313
13
Advantageously, the housing unit of the pressure testing apparatus resembles the cover unit
of the cable joint closure
Ideally, the exterior of the unit being tested is covered with a leak detection fluid.
preferably the leak detection fluid is used to cover the joint between the pressure testing
apparatus and the base of the cable joint closure and the exit point of the cables on the base
of the cable joint closure.
As the pressure within the sealed unit increases, air is forced out through the unsealed
points on the unit. It is preferable to use a leak detection fluid, which bubbles as the air
passes through it, giving a visual indication of the location of the unsealed point. If there
are no bubbles the closure has been sealed successfully, the pressure is released from the
closure using a safety valve which is attached to the inlet valve. Ideally once the pressure
has been released, the pressure testing apparatus is detached from the closure being tested.
If there are bubbles present, the preceding steps of sealing procedure are repeated until the
closure is successfully sealed.
Optionally once the polyurethane sealant has formed a very strong hard seal, a dessicant
such as silica gel can be placed within the closure to absorb any moisture that may enter
the closure over time.
Ideally the closure is re—tested on a regular basis to ensure no leaks develop over time.
Advantageously the closure is labelled with a dated sticker to facilitate this.
It is of paramount importance that the closures remain watertight and this inevitably hinges
on the characteristics of the sealing system. Therefore, the effectiveness of the sealing
system is evaluated by subjecting the closure to air tightness and temperature cycling at a
sealed pressure. Destructive tests are necessary to obtain information on tensile strength
and elongation whereas thermal ageing can provide information on the stability of the
apparatus and sealant of the invention.
TEST ONE
Temperature cycling in water testing in accordance with British telecom specification
LN450B.
Sealants and closures developed for the external network are required to withstand severe
environmental conditions during their design life span. Seasonal and climatic variations in
temperature and rainfall are large. During recent winters, temperatures of —30°C and
below have been recorded compared with midsummer temperatures of +70°C and above
for closures exposed to prolonged periods of sunlight. This clearly demonstrates the need
for materials of high thermal stability.
Thermal cycling and accelerated thermal ageing tests have been devised to provide extra
data used in evaluating the reliability of products working at these extremes. Closures of
course experience stresses in addition to those caused by climatic variations. Closures
located alongside busy roads are subjected to vibrations, which can be severe. And those
placed in unsuitable geographical locations may also be exposed to stresses from cable
creepage and other causes. Data obtained by torsion testing, flexure, impact, static loading
etc, is compiled to evaluate a closures ability to withstand such stresses as well as those
produced by external working methods.
Accordingly a CWl587 cable was installed and sealed into the cable joint closure of the
invention in accordance with the method of the invention, using the pressure testing
apparatus and sealant of the invention. The closure was sealed and the free end of the
cable was connected to a pressure monitoring system. The pressure within the closure
while being monitored continuously was increased to 400mbar (40 kPa). The joint closure
was subjected to main functional testing in water through a simulated twenty-five year life
expectancy of the joint closure. This involved monitoring the pressure of the closure while
the closure went through fifty cycles of temperature testing in water between the
temperatures of 5°C and 50°C. There was a dwell time of two hours at each temperature.
Any loss of pressure that was not attributable to the monitoring equipment would indicate
the presence of a leak, hence failure. No pressure loss was detected during this testing
procedure.
‘E 0303
TEST TWO
Functional Test for Water and Air Tightness.
A cable joint closure of the invention was fitted with a suitably sized cable and sealed
using the pressure testing apparatus and sealant of the invention. The completed closure
was pressurised to l00kPa (+/-10kPa) and immersed in a bath of water at an ambient
temperature for 30 mins(+3 mins,—0 mins). Any Visible loss of air, not attributable to
monitoring equipment will indicate a failure of this test.
The apparatus and sealant provided an air tight seal as no air was detected leaking out
through entry holes at base of the closure after sealing the closure with the sealant.
In addition ingress of water into the sealed closure was examined.
This test was performed by attaching a dome with a pressure Valve to the base of the
closure, where the cables were inserted and sealed into the closure in accordance with the
invention. Air was then pumped into the sealed closure to a pressure of lO0kPa (+/-10kPa)
Leak detection fluid was applied to the base of the closure to check for leaks.
A humidity indicator was positioned on the inside of the sealed closure to check for water
ingress.
cable joint closures were set up and tested with a multiple of cable sizes and numerous
cables in each joint to check for water ingress. No leaks were found on any of the closures.
No loss of pressure was recorded and no humidity was detected on the inside of the joint.
TEST THREE
Axial Tensile — 1000 Newton Pull Test
A CW1587 cable was installed and sealed into a cable joint Closure of the invention. The
closure was then placed in the axial tensile rig, the free end of the cable was connected to a
pressure monitoring system and the closure was pressurised to 400mbar. The closure was
then subjected to an axial tensile load of lkN via the cable for a period of 5 minutes.
During the test, the pressure was continuously monitored. Any loss of pressure not
attributable to the monitoring equipment would indicate failure against British Telecom
Specification LN450B. No pressure loss was detected during this testing procedure.
TEST FOUR
Gas Blocking of Dexbond Sealant in External Joints to BT Specification RC307
A CW1587 cable was installed and sealed into the Ready Access Closure in accordance
with the method of the invention, using the apparatus and sealant of the invention. The
sealant was permitted to flow around the cable interstices. The closure cap was not fitted,
to allow any gas to vent to atmosphere. The opposite end of the cable was installed into an
OTIAN Generic Joint 2A closure, which was used as a pressure chamber. The cable end
was left open to allow the penetration of gas along the length of the cable sample. The gas
(5% Hydrogen, 95% Nitrogen) was then connected to the pressure chamber and regulated
to 30kPa. The sample was left on test for 48 hours. During and immediately after this
period, no gas was detected using a Hydrogen Leak Detector 8012.
The invention will now be described by way of example only and with reference to the
accompanying drawings in which:
Figure l is a perspective view of a first embodiment of the cable joint closure system of the
invention;
Figure la is a perspective front view of a second embodiment of the cable joint closure
system of the invention;
Figure lb is a perspective rear view of the second embodiment of the cable joint closure
system of Figure la;
lE050571j
Figure 1c is a perspective view of a third embodiment of the cable joint closure system of
the invention;
Figure 2 is a plan view of the cable joint closure system of Figure 1;
Figure 2a is an enlarged plan View of the cable joint closure system of Figure 1;
Figure 3 is a side View of the cable joint closure system of figure 1;
Figure 4 is a side sectional view of the cable joint closure system of Figure 1;
Figure 5 is a side View of the cover section of the cable joint closure system;
Figure 6 is a perspective View of a first embodiment of the base unit of the cable joint
closure system ;
Figure 6a is a side View of the base unit of Figure 6;
Figure 6b and Figure 6c are plan views of the base unit of Figure 6;
Figure 7 is a side view of a second embodiment of the base unit of the cable joint closure
system;
Figure 7a is a plan View of the base unit of Figure 7;
Figure 7b is a perspective view of the base unit of Figure 7;
Figure 7c is a sectional perspective view of the base unit of Figure 7;
Figure 8 is a perspective view of the mounting bracket of the cable joint closure system;
Figure 8a is a side View of the mounting bracket of Figure 8;
‘M30313
18
Figure 9 is a perspective View of the collar piece of the securing collar of the cable joint
closure system ;
Figure 9a is a perspective View of the securing pin used to secure the components of the
fastening mechanism of the invention;
Figure 10 is a perspective view of the securing pin used to secure the mounting bracket of
Figure 8 and the adaptor of Figure 13 ;
Figure 11 is a perspective view of the curved bar of the fastening mechanism of the cable
joint closure system;
Figure 12 is a perspective view of the curved generally U-shaped grip of the fastening
mechanism of the cable joint closure system of Figure 1;
Figure 13 is a perspective View of the adaptor of the cable joint closure system;
Figure 13 a is a sectional plan view of the adaptor of Figurel3;
Figure 13b is a side View of the adaptor of Figure 13; and
Figure 14 is a perspective View of a fourth embodiment of the cable joint closure system of
the invention.
Referring to the drawings and initially to figure 1, there is shown a perspective View of a
cable joint closure system 100 of the invention comprising a cover unit 1, a base unit 2,
securing collar 3 formed from two semi-circular collar sections 4. The cable joint closure
system 100 also includes a mounting bracket 21 wherein the cable joint closure system is
secured to the mounting bracket 21 by means of a securing pin 23 in a first position. The
securing pin 23 and the longitudinal axis of the cable joint closure system 100 being
substantially in parallel with the longitudinal axis of the securing unit 22 of the mounting
bracket 21. The cover unit 1 is a dome shaped cover which is sealably mounted over base
unit 2. The securing collar 3 is fitted over the joint line formed when the cover unit 1 is
sealably mounted over the base unit 2.
Referring to figures la and lb there is shown a front and rear perspective View of a second
embodiment of the cable joint closure system 200 of the invention respectively. The cable
joint closure system 200 is secured to the mounting bracket 21 by means of a securing pin
23 in a second position, wherein the securing pin 23 is substantially perpendicular with the
longitudinal axis of the securing panel 22 of the mounting bracket 21.
Referring to Figure 1c, there is shown a third embodiment of the cable joint closure system
300 secured to a mounting bracket 21 in a second orientation where the longitudinal axis of
the cable joint closure system 300 is perpendicular to the longitudinal axis of the securing
panel 22 of the mounting bracket 21.
Referring to figures 2 and 2a, there is shown a plan View of the apparatus of the invention.
The securing collar 3 and mounting apparatus 21 of the apparatus are shown in figure 2 but
not in figure 2a. The presence of handle la and mounting bracket 21 enables an operator
installing the cable joint closure to choose the most appropriate method of securing the
closure system within a ready access junction. The closure system 100 can be suspended
using the handle 1a or secured to either a wall or a pole using the mounting bracket 21.
Figures 3 and 4 are a side view and a side sectional view of the closure system 100
respectively. When assembling the closure system 100 and when in use the base unit 2 is
inserted into the open end of the cover unit 1, so that the cover unit 1 is mounted over the
base unit 2. Both the cover unit 1 and the base unit 2 have radially projecting flanges 1c
and 2c respectively. When the cover unit 1 is mounted over the base unit 2, the projecting
flanges 1c and 2c lie in a juxtaposed position thereby preventing the base unit 2 of the
closure system 100 from being inserted fully into the cover unit 1. Only portion 2d (see
Figure 6) above projecting flange 2c inserts into the cover unit. Positioned in between the
radially projecting flanges 1c and 2c, is an O-ring 1d. The surface of the cover unit 1 in
contact with the O-ring 1d is tapered so as to exert maximum pressure on the O-ring 1d.
Figure 5 is a side view of the cover unit 1 of the closure system 100 showing the handle la
and radially projecting flange lc. There is a hole lb in the handle la to allow the cover unit
to be secured with other components of the cable joint closure system by means of a
polyester cord (not shown). The projecting flange lc projects outwards thereby increasing
the diameter at the open end of the cover unit 1. In the preferred embodiment of the
invention, the cover unit is formed as a single unit from a blend of Polycarbonate and
The invention is not limited to this
Acrylonitrile-Butadiene-Styrene (ABS) material.
material and any suitable material known to a person skilled in the art can be used.
Figures 6, 6a and 6b are a perspective view, side View and plan view of the base unit 2 of
the closure system 100. The projecting flange 2c is provided radially about the base unit 2
and is spaced apart from the open end (mouth) of the base unit by a predetermined
distance. This feature allows the cover unit 1 to rest on the projecting rim 2c with the
projecting rim 1c in abutment of the cover unit therewith. The diameter of the radially
projecting flange 2c of the base unit 2 is equivalent to the diameter of the radially
projecting flange lc of the cover unit 1. The upper surface of the radially projecting flange
2c has a recess 2h for receiving the O-ring (not shown). The base unit 2 is hollow and the
interior of the hollow base unit is divided into a plurality of chambers 2e and 2f. The
chambers 2e and 2f are formed by positioning a series of struts 2b within the hollow base
unit 2. The chambers 2e and 2f comprise a central main chamber 2e encircled by a
plurality of minor chambers 2f. The main telecommunication cable is housed in the main
chamber 2e of the base unit 2, the cable entering the chamber 2e through an opening (not
shown) in the sealed end of the base unit 2. The individual cables are housed in the minor
chamber 2f encircling the main chamber 2e. Where a main chamber 2e is required to
facilitate larger main cables, some of the struts 2b can be removed to provide an enlarged
main chamber 2e as shown in Figure 6c. In the preferred embodiment of the invention, the
base unit is also integrally formed as a single unit from a blend of Polycarbonate and
Acrylonitrile-Butadiene-Styrene (ABS) material. The interior surfaces of the base unit 2
and the surfaces of the struts 2b are etched to facilitate bonding of the sealant when the
base unit is being sealed as described below.
lE030313‘
In the preferred embodiment, the closure system 100 includes the mounting bracket 21.
The sleeve extension 20 of the mounting bracket 21 is shown in figures 6, 6a and 6b. The
sleeve extension 20 is moulded at one point on the cylindrical wall surface of the base unit
2. The sleeve extension 20 is generally cuboid in shape with an opening 20a on both the
top and bottom surfaces of the sleeve extension 20, (The opening on the bottom surface is
not shown) and an opening 20b on both side surfaces of the sleeve extension 20 (Only one
side opening is seen).
Referring now to Figures 7, 7a, 7b and 7c, there is shown a second embodiment of the base
unit 30 of the invention. The base unit 30 is divided into two section 30i and 30k
respectively, separated by a dividing wall 30j. The first section 30i comprises a number of
chambers 30p that are formed in the preferred embodiment continually and integrally with
the cylindrical wall 30g and the dividing wall 30j. Alternatively the chambers 30p can be
formed using struts as described above. The first and second sections 30i and 30k
respectively form the sealed end of the base unit 30. The second section 30k comprises a
removable seal 301 that has numerous openings 30n and 30m of different diameters. The
larger openings 30m are sized to accommodate large main telecommunication cables,
whilst the smaller openings 30m are sized to accommodate smaller individual cables. A
split-line (not shown) extends from each opening 30n and 30m to the edge of the
removable seal 301. The removable seal 301 is secured in position by inserting it into the
base unit 30. A gripping means is provided at the end of the base unit which receives the
removable seal 301. The gripping means comprises a partially circular ring 300 which is
generally u-shaped in cross-section. The edges of the removable seal 301 insert into the
open end of the u-shaped ring 300.
In use the second embodiment of the base unit accommodates main telecommunication
cables that are in situ in an access network and have been jointed to a large number of
individual cables. The removable seal 301 is made of a pliable material such as rubber and
can be manipulated around the cables without disconnecting any. The base unit 30 can be
pulled over the cables to the removable seal 301. The removable seal 301 is secured in
position and the base unit is sealed using a sealant as described later providing an effective
barrier against water ingress. The chambers 30p are present to enable further connections
to be made to a main telecommunications cable if so desired. The O—ring 30h and cover
unit of the cable joint closure system attach to the base unit 30 as previously described.
The base unit 30 includes the sleeve extension 20 which may be attached to a mounting
bracket or the like as described above.
Referring now to Figures 8 and 8a the sleeve receiving means 28 and securing unit 22 of
mounting bracket 21 are shown. The receiving means 28 is also generally cuboid in shape.
The securing unit 22 is a panel with either a flat or curved surface 22a with openings 22b
and 22c for screws to allow the securing unit to be removeably mounted on either a pole
or a wall. The securing unit 22 also includes a slotted opening 22d, which allows the unit
to be removably secured to a pole using a strap mechanism or stainless steel band. In the
drawings, the front surface of the receiving means 28 is shown removed, the front surface
of the receiving means 28 being the surface remote from the securing panel 22. There are
openings 21a and 21b on the top and bottom surfaces of the sleeve receiving means 28
where the top and bottom surfaces are the surfaces substantially perpendicular to the
longitudinal axis of the securing unit 22. There are also openings 21c on each side surface
of the sleeve receiving means 28. The sleeve extension 20 fits into the sleeve receiving
means 28 of the mounting bracket 21, such that the openings on the receiving means 21a
and 21b and sleeve extension 20a are aligned . A securing pin 23 (Figure 10) is passed
through the openings 21a, 20a and 21b on the surfaces of the sleeve receiving means and
sleeve extension respectively, securing the mounting bracket 2l and cable joint closure 100
together.
Figure 9 is a perspective view of a semi-circular collar section 4 which combined with a
second such collar section 4 form the securing collar 3, used to further secure the closure
system 100 by exerting maximum pressure on the joint line between the cover unit 1 and
base unit 2 and hence on the O-ring, maximising seal integrity.
The collar pieces 4 are generally u-shaped in cross section, such that when the collar
assembly 3 is formed, there are two distinct diameters within the collar assembly 3, the
first diameter extends between two points on the surface of the arms 4b of the u-shape
remote the base of the u-shape, whilst the second diameter is defined as the diameter of the
!E03O31j
23
circular unit from a first point on the internal surface of the base 4a of the u-shape to the
diametrically opposite point on the internal surface of the base of the u-shape. The first
diameter is equivalent to the diameter of the cover unit 1 (figure 4) and is smaller than the
second diameter, which is equivalent to the diameter of the radially projecting flanges lo
and 2c (figure 4).
The means by which the two semi-circular collar sections 4 are combined to form the
securing collar 3 shall now be described with specific reference to Figures 1, la, lb, 1C, 2,
4 and 9. The two semi-circular collar sections 4 are hingedly attached together at a first
point 11 using a simple hinge and securing pin mechanism. Once hinged, the two semi-
circular collar sections 4 are secured together using the fastening mechanism at a second
point 9a. The semi-circular piece 4 has a pair of ring attachments 9b and 9c, which
radially project. When the collar assembly 3 is formed, the pair of ring attachments 9b and
9c on each semi-circular piece 4 do not directly connect with the other pair of ring
attachments. There is a space 9d positioned intermediate each ring attachment 9b and 9c
within a pair. Each ring attachment 9b and 9c within a pair is positioned directly in line
with the other such that the central opening 9e on each ring attachment is in line with the
other in its pair.
The semi-circular collar section 4 has a third ring attachment 10 positioned radially
projecting from the external surface of the base of the u-shape on each semi-circular piece
4. The third ring attachment 10 is positioned in line with the space 9d positioned
intermediate each ring attachment 9b and 9c within a pair.
Figures 9, 9a, 11 and 12 are perspective views of the components of the fastening
mechanism of the invention comprising a securing pin 7, an arcuate bar 5 and a grip 6
which has a generally U-shaped profile. The grip 6 tapers at the closed end thereof. The
complete fastening mechanism is shown secured on the joint cover system 100 in Figure
The arcuate bar 5 has an opening 5a at each end for securing the arcuate bar 5. The grip 6
is in the form of a generally arcuate wedge shape, with the U-shaped section 6d being
'E°303
formed at the thicker end of the wedge and the grip section 6c is formed at the tapered end
of the wedge. There are two pairs of openings 6e and 6f for securing the u—shaped grip.
Ideally each opening within a pair 6e and 6f is positioned opposite the other opening in a
pair on the arms 6a and 6b of the u—shape section 6d. The curved bar 5 inserts into the
centre of the u—shape section 6d between the arms 6a and 6b. The bar 5 and u—shaped grip
6 are secured together by passing a screw through a pair of openings 6e on the u—shaped
grip 6 and and an opening 5a on the bar. The grip 6 is pivotable about these openings when
secured.
Referring to figures 1, 9, 9a, ll and 12 the unattached end of the arcuate bar 5 ( the
opposite end being attached to the curved u—shaped grip) is positioned in the space
intermediate 21 first pair of ring attachments 8 on a first semi—circular piece 4. A screw
placed through the openings on each ring attaclunent and the other opening 5a on the
curved bar secures the curved bar 5 in position. The arcuate bar is pivotable about the ring
attachments 8 when secured. The arcuate bar 5 is sufficiently curved that it passes
through the space intermediate a second pair of ring attachments 9 on the second semi-
circular piece 4. The arms 6a and 6b of the u—shaped grip 6 are positioned the same
distance apart as the rings 9 of the second ring attachment. The ends of the arms 6a and 6b
of the u—shaped grip 6 remote the grip section 6c are in contact with the rings 9 of the
second ring attachment. The end of arms 6a and 6b of the u—shaped grip 6 in contact with
the ring attachments 9 are curved to facilitate movement of the u—shaped grip 6 as it moves
about the ring attachments 9 thus clamping the fastening device. As the u—shaped grip 6
moves about the ring attachment 9 towards the cable joint closure 100 the circular unit is
tightened to a pre-assigned tension providing a further means of securing the cable joint
closure 100 against water and air. Once the u—shaped grip 6 has secured the two semi-
circular pieces 4 a securing pin 7 is passed through the openings 6f nearest the grip 6c of
the u—shaped grip 6 and the openings on the third ring attachment 10a to prevent the
fastening mechanism from opening without interference. The third ring attachment lOa on
the other semi-circular collar piece 4 can be used to secure the fastening mechanism to
other components of the closure system by means of polyester cord (not shown).
IE 0303
The securing pin 7 used to secure the fastening device is the same as the securing pin 23
used to secure the mounting bracket 21, but is smaller in size. Each securing pin comprises
a cylindrical pin 25 having a grip 24 at one end and a pointed tip 26 at the other. The
diameter of the pointed tip 26 is slightly greater than that of the cylindrical body 25 of the
pin. A central portion 27 of the tip 26 is removed allowing the tip of the pin to compress
as it passes through openings. Each securing pin has a hole in the grip 24 that allows the
securing pin to be secured with other components of the closure system by means of
polyester cord.
Referring now to Figure 13, 13a, 13b and 14, there is shown an adaptor 40 comprising two
sections, a receiving section 40b and an insertion section 40a. Both the receiving section
40b and insertion section 40a are generally cuboid in shape. The receiving section 40b acts
in the same way as the sleeve receiving means 28 of the mounting bracket 21 (Figures 8
and 8a). The sleeve extension 20 of the base unit of the cable joint closure system 400 fits
into the receiving section 40b and is secured by passing a securing pin 23 (Figure 10)
through the openings 40c and 23a or 23b on the receiving section 40b of the adaptor 40
and the sleeve extension 20 respectively. The insertion section 40a of the adaptor 40
inserts into a cable bearer bracket 50. The adaptor 40 is secured to the cable bearer bracket
50 by passing a fixing pin (not shown) through the openings 40d and 50a of the insertion
section 40a of the adaptor 40 and the cable bearer bracket 50 respectively. In use the
telecommunications cable joint closure is installed using the following method, the method
comprising the steps:
. Removing collar assembly, cover unit and O-ring.
. Select chambers to be drilled using a step conical drill bit. For a loop
cable use the main chamber and for all individual ancillary cables use
remaining minor chambers.
Ancillary Cable Preparation
Mark and circumferentially cut sheaths on all ancillary cable
mm.g Do not remove sheath)
Loop Cable Preparation
Mark and cut 520mm joint gap
Remove cable sheath and place / secure joint in a polyethylene (PE)
bag.
Using a wet wipe isoparaffin solution towel clean all ancillary cable
sheaths and loop cable sheaths and the polyethylene bag containing
the joint. Then using the dry wipe clean the residue from all cable
sheaths.
Feed the cables through their appropriate chamber holes, ensuring
the cable butts are positioned to within approximately 20mm of the
top of the chambers.
Apply the putty tape around each cable and press firmly to the
underside of the base unit.
Load the sealant cartridge in the cartridge dispenser. Squeeze the
trigger to dispense the sealant.
Dispense the sealant to each chamber where the cables are installed.
The sealant should be dispensed to within 10mm of the top of the
chamber. By placing the cable butts beneath the sealant cable
sealing a water block is achieved.
Do not apply any mechanical stress to the sealed cables for 20
minutes after the sealing has taken place.
The joint can be tested to prove the integrity of the joint using a
specially adapted pressure testing apparatus to facilitate pressure
testing.
J ointing between the main cable and individual cables can commence
after 25 minutes of starting the cable sealing process.
Tie off desiccant packs to the spliced terminations to absorb any
moisture in the closure. Attach packs using binding wraps or tape
binding.
Clean the O-ring recess on the closure base unit. Clean and replace
the 0- ring. Mount the cover unit over the base unit and lock into
position using the collar assembly. The fastening mechanism should
be locked in the closed position using the securing pin provided.
Closure Mounting Procedure.
Underground Installation.
The mounting bracket can be screwed to the sides of the chamber wall to
facilitate the complete installation.
Alternatively,
If cable bearer brackets are fitted to the underground chamber the closure
can be installed directly to the “U” channel of the cable bearer bracket by
using the adaptor and fixing pin which is inserted through the charmel
and the closure spigot fixing hole, thus retaining the joint in the desired
vertical or horizontal position.
Overhead Installation.
Using 2 off 8 x 50mm coach screws, secure the mounting bracket in the
desired position on a pole.
It will of course be understood that the invention is not limited to the specific details
described herein, which are given by way of example only, and that various modifications
and alterations are possible within the scope of the invention.
MACLACHLAN & DONALDSON,
Applicants’ Agent,
Merrion Square,
DUBLIN 2.
Claims (5)
1. A telecommunication cable joint closure comprising a cover unit, a base unit, a sealing means and a securing collar, the cover unit being sealably mountable on the base unit to form a joint line, a sealing means locatable between the cover unit and the base unit wherein the securing collar is sealably mountable over the joint line and the collar being adapted so that in use the collar is mounted over the joint line so that the collar cooperates with the seal means to substantially fully form a seal about the cover unit and the base unit.
. A telecommunication cable joint closure as claimed in claim l, wherein the cover unit of the telecommunication cable joint closure comprises a hollow generally cylindrical shape sealed at a first end and open at a second end, the sealed end of the cover unit preferably having a generally curved surface forming a dome shaped seal and the open end of the cover unit has a radially projecting flange where the flange projects outwards and it is preferable for the sealed end of the cover unit, the cover unit and the radially projecting flange to be formed as a single unit and ideally the cover unit is made from a blend of Polycarbonate and Acrylonitrile-Butadiene-Styrene (ABS) material.
. A telecommunication cable joint closure as claimed in claim 1 or claim 2, wherein the base unit of the telecommunication cable joint closure also comprises a generally hollow cylindrical shape, optionally in which the base unit is sealed at a first end and open at a second end; the sealed end of the base unit has a flat surface enabling the base unit to stand on the sealed end when desired; and the base unit of the telecommunication cable joint closure has a radially projecting flange.
. A telecommunication cable joint closure as claimed in any one of the preceding claims, wherein in use the cylindrical surface of the base unit intermediate the open end of the base unit and the radially projecting flange inserts into the open end of the cover unit, so that the cover unit is mounted over the base unit and the projecting flanges of both the cover unit and the base unit lie in a juxtaposed position, optionally in which; when the base unit inserts into the open end of the cover unit, there is a degree of overlap between the cylindrical surfaces of the base unit and the cover unit; the radially projecting flanges of both the base unit and the cover unit provide a stop means that prevent the base unit from inserting fillly into the cover unit; the degree of overlap of the cylindrical surfaces of the base unit and cover unit is determined by the position of the radially projecting flange on the base unit; the radially projecting flange on the base unit can be positioned at any required distance from the open end of the base unit; the radially projecting flange of the base unit is positioned approximately 15 mm from the open end of the base; and the flange is positioned intermediate the open and sealed ends of the base unit; and optionally in which:- the sealing means comprises an O-ring which is positioned intermediate the projecting flanges of the cover unit and the base unit; the upper surface of the radially projecting flange of the base unit has a recess for receiving the O-ring, the upper surface being defined as the surface closest to the open end of the base unit; the recess is of insufficient depth to fully accommodate the O-ring it merely acts as a receiving means for the O-ring; the recess has a depth of approximately 1.5 mm; the interior surface of the cover unit that is in contact with the O-ring is engineered to exert maximum pressure on an increased surface area of the O- ring to form a tighter water/air seal than is commonly found on cable joint closures; this effect is achieved by tapering the area of the interior surface of the cover unit in contact with the O—ring; the area of the cover unit in contact with the O-ring is the interior surface of the open end of the cover unit wherein the radially projecting flange projects from the cylindrical side walls of the cover unit; and optionally in which once the cable joint closure is assembled, the closure is further secured by means of a collar assembly designed to exert maximum pressure on the joint line hence the O-ring, maximising seal integrity, and optionally in which; the interior of the hollow base unit is divided into a plurality of chambers; the chambers are formed by positioning a series of struts within the hollow base unit where the struts are perpendicularly connected to the interior flat surface of the sealed end of the base unit; the struts are also connected to the interior surfaces of the side walls of the base unit; the plurality of chambers comprise a central main chamber encircled by a plurality of minor chambers; the main telecommunication cable is housed in the main chamber of the base unit of the cable joint closure; the main telecommunication cable enters the main chamber through an opening in the sealed end of the base unit; the opening in the sealed end of the base unit is only formed on site when the cable joint closure is being brought into use; there are pre-assigned hole markers on the sealed end of the base unit to direct and guide when forming the opening, and optionally in Which; the base unit is made as a single unit with the struts formed integrally within the base unit this can be achieved by blow-moulding the base unit; a blend of Polycarbonate and ABS material is used to form the base unit.
5 . A telecommunication cable joint closure substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
Publications (2)
Publication Number | Publication Date |
---|---|
IE20030313U1 true IE20030313U1 (en) | 2004-11-03 |
IES83730Y1 IES83730Y1 (en) | 2004-12-30 |
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