Note: Descriptions are shown in the official language in which they were submitted.
METHOD AND APPARP~TUS FOR h~SING A C~BIE SPLICE
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Field of the Invention
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This invention relates to splice enclosures for telephone
cable, and more specifically, relates to an elongated flexible
splice housing.
The trend in modern housing developments has been to run
all utility service, including telephone lines, underground.
Individual service lines from each housing must be spliced into a
multiline telephone cable running along the property lines of the
houses. Some type of watertight junction box, such as described
in U.S. Patent No: 3,848,074 issued to William H. Channel
has been used to allow a splicer to tie the service line from the
house into the multiline cable. If not properly installed and
sealed, however, the junction box may be a source of trouble. In
addition, the splicer must be a highly skilled tradesman to insure
that the connections between the service line and the multiline
cable are properly completed.
To avoid these and other problems in the use of on-site
installations of such junction boxes, ways have been sought to
use pre-wired factory-installed splices. This requires that the
cable splices be performed at a central plant location and the
cable with its pre-spliced service lines attached then transported
to the location for ins-tallation. Because rather substan-tial lengths
of cable may be involved, it is desirable that the individual splices
be sealed in enclosures which are coaxial with the multiline cable
and are sufficiently flexible and small enough in diameter that the
spliced cable assembly can be wound on large spools for delivery to
the installation site.
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The current method of making such flexible splices in a
cable assembly has been to lay the cable out in a large assembly
area, complete the individual splices at the required intervals, and
then seal the individual splices by means of a heat shrinkable
material which is wrapped around the cable splice. A portable oven
is moved from splice location to splice location to heat the sealing
material. This material must then be allowed to cool to complete the
shrinking process and to provide the necessary structural strength
and stability to permit the cable to be moved and rolled onto the
transporting spool. Such an arrangement is time-consuming as well
as requiring a substantial capital investment in space and portable
oven equipment. The heating process is also wasteful of energy.
Accordingly, there is provided a flexible cable splice
enclosure comprising a tubular housing of soft resilient flexible
material having integrally formed tubular end portions at either
end, the tubular housiny freely bending in an arc along its longit-
udinal axis, each end portion having a resilient tapered interior
wall, means providing a continuous rigid non-expandable band surround-
ing said tapered wall to limit outward expansion of the resilient
flexible material forming said tapered wall, a tapered plug of
resilient flexible material surrounding the cable inserted into
each end portion of the tubular housing and means forming a lip
projecting radially inwardly of the tapered surface at the outer
margins of the tapered walls for retaining the plugs in the end
portions of the housiny.
merefore, the present invention is dire~ted to an improved cable
splioe enclosure which is sufficiently thin and flexible to be readily wound on
a spool as an integral part of the associated cable. me enclosure is easily
installed to enclose the cable splioe, providing moisture-proof protection, yet
~` 30 being thin and flexible enough to permit the
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1 cable with the splices installed to be wound tightly on a
spool for storage and delivery to the cable assembly. This
is accomplished, in brief, by providing a cable splice
enclosure comprising an elongated tubular housing of
resilient flexible elastomeric material which surrounds
each splice connection of service lines to the cable. The
ends of the tubular housing terminate in integrally formed
radially offset tubular end portions having tapered inner
surfaces. The offset portions are each inserted inside an
annular collar having turned-in lips at eithar end which
secure the collars against axial movement. Grommets - -
through which the cables pass form plugs at either end of ~ -
the enclosure. The plugs are tapered to engage the inner ~ -
surfaces of th~ offset portions of the tubular housing
within the collars. When in place, the larger diameter
outer end of each tapered plug engages the lip at the outer
edge of the respective collar to lock the plug in position.
Description of the Drawings
For a more complete understanding of the invention
reference should be made to the accompanying drawings,
wherein:
FIG. 1 is a side ~iew of th~ splice enclosure;
FIG. 2 is an end view of the splice enclosure;
FIG~ 3 is a partial sectional view taken substantially
~5 on the line 3-3 of FIG. 2; ~ ~-
FIG. 4 is a partial sectional view of molding equip- : -
ment used in explaining the method by which the housing is
injection molded; and
FIG. S is a sectionalview~similar to FIG. 3 showing
an alternative embodiment to the present invention.
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1 Detailed Description
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Referring to the drawings in detail, the numeral 10
indicates generally the cable splice enclosure of the
present invention. The enclosure is coaxial with a multi-
line telephone cable 12 to which one or more service lines
are connected at a common splice, two service lines being
indicated at 14. The service lines are spliced into the
appropriate lines of the cable 12 within the housing 10
using conventional splicing techniques. Similar splices are
made at intervals along thç length of cable.
The enclosure 10 for the cable splice includes an -
elongated tubular housing member 18. The housing is molded,
in a manner hereinafter described, from a resilient flexib~
material such as natural or synthethic rubbers or other
well known elastomeric materials. The tubular shape of the
housing element 18 is maintained by a coil spring 20
embedded in the walls of the housing~ The coil spring 20
maintains the tubular shape of the housing while at the
same time permitting the housing to be easily bent or flexed
into an arcuate shape when the cable 12 is wound on a spool.
The housing 18 is provided at each end with an integrally
formed radially offset tubular end portion 22. The offset ~ ;
end portion forms an inner shoulder 24 and an outer shoulder
26 at the junction between the offset portion and the
central portion of the housing 18. The inner surface 28 of
the offset portion 22 is flared or tapered outwardly at an
approximate taper of 5. The outer edge of the offset
portion is ~ormed with a thin annular projection 30, the
inner section between the tapered surface and the projec-
tion 30 orming a shoulder 32.
~ he offset end portions 22 of the housing 18 are each
insertcd in ~ rigid collar, indicated at 39. The collars
are molded from a suitable rigid plastic, such as poly-
eth~lcne. To secure the offset portion within the collars
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1 and hold the collars in place, each collar is formed withan inwardly projecting inner lip 38 which engages the
shoulder 26 of the housing member 18. The outer edge of
each collar 34 is formed with an inwardly projecting outer
lip 40 which is formed with a smooth arcuate outer surface
and with an inner undercut groove into which the thin outer
portion 30 of the offset portion 22 of the housing fits.
Because the housing is made of a flexible resilient
material, the offset portion can be squee7ed into the
central space between the inner and outer lips of the
collar. Once in place, the resilient material expands
outwardly to its normal shape in which it fits snugly
against the inner cylindrical surface of the collar.
A multiline cable and the service lines enter the
housing through either end. To provide support ~or the
cables and to provide a seal between the cables and the
enclosure, a pair of grommets 42 are provided, one at
either end. Each grommet is made of an elastomeric material
such as natural or synthetic rubber and is shaped to form a
tapered plug which is inserted into the offset portion 22
within the associated collar 34 of the housing 18. The
outer surface of the grommet 42 is ~apered to the same
taper as the inner surface of the offset portion 22. The
grommets are provided with a central hole 44 through which
the large multiline cable 12 passes into the splice
enclosure, and smaller off-center holes 46 through which
the service lines 14 pass into the housing. The grommet 42
may be split, as indicated at ~, to permit the grommet to
be expanded to slip over the cable 12. When in assembled
position, as shown in FIG. 3, the grommet 42 is in a state
of compression by the rigid collar, insuring a moisture-
tight seal at the tapered interface between the outside of
the grommet 42 and the surrounding offset portion 22. The
compression of the grommet also insures that the grommet
3~ clamps down securely around the cable and service lines
1 where they pass through the holes 44 and 46. When in
position, the grommet 42 seats against the inner shoulder
24 of the housing.
To insure that the grommet is placed in a state of
compression and remains in place, the diameter of the
smaller end of the tapered grommet is made substantially
the same diameter as the opening formed by the lip 40,
which in turn is approximately the same diameter of the
tapered inner surface of the offset portion 2~ as measured
at the shoulder 32.
The enclosure of the present invention is installed
by first inserting the ends of the service lines 14 through
the openings of the grommet. The tubular housing portion
is slipped over one end of the cable 12. ~he splice
connection is then formed between the service lines 14 and
the multiline cable 12. The split grommet is then spread
sufficiently to sli~p onto the cable 1~ adjacent one end of
the splice. A suitable lubricant is applied to the outer
surface of the grommet 42 and then the housing member 18,
with the collars 34 in place, and the grommet 42 are forced
together by inserting the tapered end of the grom~et 42
into the opening in the adjacent collar. Once the grommet
is seated against the inner shoulder 24, the outer edge of
the grommet expands behind the lip 40 of the collc~r, locking
the gromrnet in place. As pointed out above, the rigid collar
34 maintains the resilient material of the offset portion
22 and the grommet 4~ in a state of compression so that the
grommet clamps and seals the cable and service lines where
they pass through the grommet, as well as sealing the
interface between the grommet and the offset portion of the
housing member. Once the grommet at one end of the
enclosure is in place, the grommet at the other end of the
enclosure is slipped over the multiline cable and compressed
into the offset portion at the other end of the housing
through the other collar 34, thereby fully enclosing the
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1 splice connection between the service lines 14 and the
multiline cable 12. The enclosure with its flexible
tubular housing 18, being coaxial with the multiline cable
12 and being flexible along its length, permits the cable
assembly to be wrapped on a spool as each splice along the
length of the cable is completed~
An alternative embodiment of the present invention
is shown in FIG. 5. The ~ubular housing member 18 with its
embedded coil spring 20 and integrally formed radially
offset tubular end portions 22 is substantially the same as
the arrangement of FIG. 1. However, in place of the
separate rigid plastic collar 34, a cylindrical metal sleeve
or band 34' is embedded in the end portion 22 during the
molding process. The metal sleeve 34', like the collar 34
15 of FIG. 3, acts as a restraining element when the tapered '
grommet 42 is inserted in place. An integrally molded
inner lip 40' on the outer edge of the offset end portion ~ -
22 holds the grommet,against the inner shoulder 24. The
grommet 42 may be molded with a rounded nose portion 42' '
which helps to ~enter and guide the splice as it is drawn
with the cable through underground conduit. '
Referring to FXG. 4, there is shown in injection
molding arrangement for molding the housing 18 with its
embedded coil ~pring 20. The mold includes an outer annular
female mold section 50 and an inner arbor 52 which form a
cavity 54 which conforms to the desired shape of the molded
housing 18 with its offset end portions 22. With the mold ~ -
open, the coil spring 20 is slipped over the arbor 52 into
the cavity 54. The uncured latex is then injected into the
cavity under pressure by a suitable drive piston 56 which
forces the latex through a passage 58 into the end of the
cavity 54. A similar injection piston may be provided at
the opposite end of the cavity so,that the latex is injected
from both ends. Such conventional molding technique is
well known.
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l However, it was found that the consistency of the
uncured molding material was such that the spring 20 was
compressed from either end during the injection process
and tended to remain compressed during the curing. It was
found that this problem could be overcome by providing a
manifold arrangement to individual injection passages 60
spaced along the length of the cavity 54. The position of
the passages 60 is such that the uncured molding material
is injected between each of the convolutions of the coil
l~ spring 20. This injection arrangement acts to balance any
forces imposed on the spring 20 by the molding material as
it is injected into the cavity 54.
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