Note: Descriptions are shown in the official language in which they were submitted.
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WIRE STRIPP~R
This invention relates to a device and method for
stripping the outer jacket from the inner core o an electric
cable or the like. More particularly, the i.nvention concerns
the use of a high-pressure jet of fluid as 21 cutting instxument-
ality which allows the outer jacket to be sepaxated from the
inner core of the electric cable without damage to the inner
core.
It is desirable to separate and salvage the inner
core and outer jacket of long lengths of electrical cables which
have ~een damaged or rejected for failure to meet quality control
standards during manufacture o the like. A technique used for
stripping the outer jacket from the inner core of such cable
involves cutting a score mark along the length of the outer
jacket and then separating the inner core from the outer iacket
along the s.core mark.
Several techniques have been developed for scoring
the outer jacket which include the use of instrumentalities
such as cutting knives and lasers. However, these techniques
have several drawbacks. Utilizing cutting knives, the process
is very time consuming and requires frequent maintenance since
the outting knives quickly become dull. Further, the cutting
.knives tend to nick the material beneath the outer jacket and
thereby damage it. Systems which utilize lasers are extremely
expensive and also have a tendency to cut too deeply and damage
material beneath the outer jacket.
Accordingly, it is an object o the present invention
to provide an improved device and method for stripping the
outer jacket from the inner core o an electric cable.
Another object of the present invention is to provide
an improved device and method of the type described for stripping
the outer jacket from the innex core of an electric cable with-
out damaging the inner core.
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Still another object of the present invention
is to provide an improved device and method of the type
described which is low in cost and requires little main-tenance.
In accordance with one aspect of the present
invention there is provided a method fo.r stripping a flexible
outer jacket from the inner core of a flexible cable.
The method comprises the s-teps of: genera-ting a concentrated
jet of fluid under pressure sufficient to cut the outer
jacket; directing the jet of fluid a-t the cable thereby
cutting the outer jacket, and separating the inner core
and the outer jacket along the cut.
In accordance with a second aspect there is
provided a device for stripping a flexible outer jacket from
the inner core of a flexible cable. The device comprises
a source means for producing a fluid jet having an orifice
through which the fluid jet exits the source means in a
stream narrow relative to the diameter of cables to be
! stripped. The source means includes pressure means for
drivlng the fluid jet at pressure great enough to cut at least
part way through the outer jacket of a cable. The device
also includes guide means for supporting a cable a
predetermined distance from the orifice with the cable
centered on the orifice to intercept the fluid jet along the
center of the cable, drive means for moving the cable
relati~e to the orifice at a rate at which the fluid jet cuts
at least part way through the outer jacket, and separating
means for separating the inner core from the outer jacket
along the cut.
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Other objects of the present inven-~ion in addition
to those set fort~l above will become appclrcnt to those skilled
in the art from ~he following description, taken in connection
with the accompan~ ig clrawings wherein:
~ IC,U~E 1 is a sectional view of a device constructed
in accordance Wit}l the invent.~on;
FIG~R~ 2 is a sectional view taken gen~rally along
the line 2-2 of ~IGURE l;
FIGURE 3 is a sectional ~iew taken ~enerally along the
line 3-3 of FIGURE 1~
FIGU~E fi is a sectional view of an eleetric c~ble
which has been scored with the device of the present inventioil;
FIGU~E 5 is another embodiment of a device constructed
in accor~ance with the present invention; and
~ IGURE 6 is a.sectional vi~w of an electric cable
hich has been scored with the device of FIGURE 5.
The present invention is directed to an improved
! device and method for stripping the outer 3acket from the inner
~ore of an electric cable~ Broadly stated, the device of ~he
present invention comprises means.for generating a hiyh-pressure
jet of fluid, means for directing the jet along ~he length of
the electric cahle thereby cutting a score mark along the length
of the outer ~acket, and means for separating the inner core
from the outer jacket along the score mark.
Re~erring more ~articularly to the drawings, and
initially to ~IGURES 1 through 3, the device of the present
; invention is shown separating an outer layer of insulation 10
from an inner conductor 1~ of an insulated wire 14. The device
of ~he present invention comprises a wlre transport system which
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includes coplanar disc-shaped idlers 16, 18, 20, and 22 which
are freely ro~atable about parallel axes and which have outer
slotted edges 24, ~6, 2~, and 30, respectively. The unstripped
wire 14 is originally wound around a reel 32 which is also
rotatable about an axis parallel to the axes of the idlers and
located below the idler 16. From the supply reel 32, the cable
14 rides on the top of the idler 16 within the slot 29 in a
clockwise direction and then rides on the bottom of the idler
18 within the slot 26 in a counterclockwise direction.
In keeping with the present inventlon, the means for
generating a high-pressure jet of fluid comprises a high-pressure
supply of water 34 connected by a hose 36 to a nozzle 38 which
is located near the top of the idler 16 centered directly over
the wire 14. ~n orifice 40 in the nozzle 38 is locatecl close
to the outer surface of the wire 14 and positioned to direct
a cont:inuous needle-like high-pressure jet of water perpendicular
to the axis of the wire 14. It is noted that the water could
be replaced with a water-polymer solution. The orifice 40 is
located close to the surface of the wire to insure that the
energy of the jet of water is sufficient to cut through at least
a substantial portion of the thickness of the insulation 10 to
the inner conductor 12. As the wire 14 moves past the nozzle 38,
a score mark 42 is cwt into the insulation 10 along the length
o~ the wire 14 (see FIGURE 2). The score mark 42 is deep enough
to penetrate completely the insulation 10 without damaging the
inner conductor 12. Sufficiellt tension is kept on the wire 14
to ensure that the distance of the orifice 40 from the outer
surface of the wire 14 will be approximately the same through
out the entire length of the wire 14.
In keeping with the pxesent invention, the inner con-
ductor 12 is separated from the insulation 10 in the following
manner. As the wire 14 comes in contact with the bottom of the
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slotted edge 26 of the 1dler 18, the score mark ~2 is located
near the center of the slotted edge ~6 (see FIGURE 3). At
this point, the innex conductor 12 and the insulation 10 separ-
ate. The inner conductor 12 extends up and rides on the top
of the idler 20 in the slotted edge 28 in a clockwise direction,
and on to a take-up reel 44. The insulation 10 extends down
alid rides on the top of the idler 22 in the slotted edge 30 and
on to a take-up reel 46. The idler 20 is located sufficiently
above the idler 22 so that the inner conductor 12 is pulled
from the insulation 10 along the score mark 42.
The necessary pull or tension to carry wire 14 tautly
along the reels and separate the inner conductor 12 from the
insulation 10 is provided by the take-up reels ~4 and 46 which
are both driven by a core 48 in a clockwise direction.
There are a number of variables that will affect the
performance of the system, such as: water pressure, size of
nozzle, configuration of nozzle, distance of nozzle from wire,
and wire speed. All of these variables are adjusted to ensure
that a score mark of sufficient depth is cut lnto the insulation
10 without injuring the inner conductor 12, and also to maximize
the speed with which the wire 14 is run through the device of
the present invention.
It is noted that there is a distinct advantage in
using a high-pressure iet of fluid instead of instrumentalities
such as knives and lasers to cut a score mark through the outer
layer of insulation along the Iength of an insulated wire.
Both knives and lasers can cut or nick the inner conductor there-
~by destroying its salvage value. On the other hand, although
a high-pressure jet of water can readily cut through most non-
metallic materials such as neoprene rubber, polyolefins, poly-
vinyl chloride, and other materials from which the layer of
insulation of an insulated wire is fabricated, it has little
s~
t
effect on metallic materia].s such as the materials from which
the inner conductor of an insulated wire is fabricated. There-
~ore, tlle device o~ the inventi.on which uti:Lizes a high-pressure
water jet to cut a score mark along the length of the layer of
insulation can be operated at an extremely :East rate without
damaging the inner conductor.
It is noted that the device of the present invention
can also be utili~ed to strip the outer jac~set from cables having
inner cores consisting o~ various components without''damagi.ng the
inner cores. For example, the device of the present invention
can be utilized to strip the outer jacket from a cable having an
inner core consisting of one or more insulated wires without
damaging the insulated wires, whereby the inner wires can be
salvaged and reused.
FIG~RE 4 shows a cross~sectional view of a two-conductor
unshielded cable 50 having an outer jacket 52 and an inner core
54-comprising a pair of insulated wires. The outer jacket 52 can
be fabricated from various materials such as rubber, plastlc, or
vinyl. The inner core 54 includes an insulated wire 56 having
an inner conductor 58 and an outer layer of insulation 60, and
an insulated wire 62 having an inner conductor 64 at an outer
layer of insulation 66. The device of the present invention can
~e used ~o separate the wires 56 and 62 from the outer jacket
52 without damaging the insulation 60 and 66. To this effect,
the device of the present invention is used to cut a score mark
6B along the length of the outer jacket 52 which does not com-
pletely penetrate the outer jacket 52. The parameters of the
device of the invention are regulated to ensure that the score
mark 68 penetrates only about 70-90 percent through the outer
jacket 52.
By not completely penetrating through the outer jacket
52,.it is ensured that the insulation 70 and 66 will not be
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dama~ed so that the wires 56 and ~2 can be salvaged and ~herefore
reused. The depth of the score mark 68 is deep enough so that.
the inller core 54 can be pulled from the outer jacket 52 mechan-
ically therehy breaking through a remaining portion 69 aloncJ the
score mark 68.
It is noted that problems arise when other instrument-
alities such as knives are used to cut a score mark along the
length of a cable without penetrating through the outer jacket.
Due to imperfection in the wire transport system and nonuniformity
1~ of the thickness of the cable along its length, the relative
distance from the top of the cable to the cutting edge of the
cutting knife varies as the cable moves past the knlfe thereby
creating a probability that the knife will cut too cleeply through
the outer jacket, possibly da~laging the inner core and thereby
destroying it. This problem becomes more acute for cables having
outer jackets which are not cylindrical in shape, for example,
a cable comprising a pair of -twisted wires encased in a flexible
outer jacket which molds to the general contour of the twisted
pair of wires.
On the other hand, the cutting power of a jet of fluid
is xelatively constant for distances close to the orifice of the
nozzle. There can be small variations in the distance separting
the nozzle and the outer surface of the cable that do not affect
the depth of the cut, and the variation that can be experienced
without any significant loss of effectiveness or damage is much
greater than that which can be tolerated with mechanical cutting
knives. Thus, the cutting power and therefore the depth of the
cut will be relatively constant irrespective of nonuniformities
in the cable and imperfections in the transport system which
3Q vary the distance between the orifice of the nozzle and the
surace of the cable as the cable passes unc~er the nozzle. By
carefully regulatincJ the power of the jet of fluid and the speed
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of the cable past the nozzle, the depth of the cut can be
accurately controlled to preven~ the iet of fluid from cutting
through the outer jacket and thereby possibly damaging the inner
ccre and destroying its salvage value.
During operation of apparatus embodying the present
invention, a two-conductor 19 gauge unshielded cable having a
nominal outer diameter of 0.162 inch, with a vinyl outer jacket
of 0.025 inch thickness was subjected to a high-pressure jet of
water at 15,000 psi. The water was emitted in a needle-like
stream from a continuous flow nozzle having a round ori~ice with
an inside diameter of 0.005 inch. The cuttiog speed was 50 feet
per minute with the orifice located about 0.25 inch Erom the
surface of the cable:
In keeping with the present invention, another embodi-
ment is shown in FIG. 5 separating an outer jacket 70 from an
inner core 72 of a two-conductor unshielded cable 74. The cable
74 is similar in construction to the cable 50 shown in FIG. 4,
with the inner core 72 comprising a pair of lnsulated wires 76
and 78. The device illustrated in FI~. 5 removes the outer
jacket 70 from the inner core 72 by scoring the outer jacket 70
along its length on opposite sides and then pulling the outer
jacket 70 apart along the score marks.
Referring to FIG. 5 cable 74 is shown to originate from
a supply reel 80 and it travels through two pairs of guide rollers
82 and 84 so that the cable 74 is directed between nozzles 86
and 88 which are both similar in construction to the nozzle 38
shown in FIG. 1. The nozzles 86 and 88 are each connected by
a hose 90 to a high-pressure supply of water (not shown) and are
both positioned close to the surface of the cable 74 so that
each directs a continuous needle--like high-pressure jet of water
perpendicular to the axis and along one side of the cable 74.
As the cable 74 passes under the nozzles 86 and 88 a pair of score
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marks are cut on opposite sides along the length of the cable.
The score marks preferably penetrate the outer jacket 70 approxi-
mately 50 percent: to insure ~hat they will not penetrate through
to the inner core 72. FIG 6 shows a cross-sectional view of the
cable 74 with score marks 92 and 94 cut on opposite sides. As
the scored cable 74 passes the pair of guide rollers 84, the
o~iter jacket 70 is pulled apart along the score marks 92 and 94
forming two outer jacket halves 96 and 98. The outer jacket half
96 rides in a stripper capstan 100 and the outer jacket half 98
rides in a stripper capstan 102 and are each wound onto take-up
reels not shown in the figures. The inner core 72 separated from
the outer jacket 70 is collected on a take-up reel 104.
By scoring~the outer jacket on opposite sides rather
than on only one side, it is possible to make a shallower cut
which further enhances the ability of the device of the present
invention to prevent damage to the inner core when the outer
jacket is pulled away. Further by pulling the two halves of the
outer 3acket apart along two score marks rather than pulling the
inner core from the outer jac~et along one score mark there is
less likelihood of damaging the inner core. For example, with
this embodiment the device of the present invention can be used
*o separate the outer jacket from a cable having an inner core
wrapped in tissue paper tape without destroying the ta2e when
the outer jacket is separated from the inner core.
In keeping with the present invention, another embodi-
ment can be used to enable the stripping of a selected portion
of insulation from the inner conductor of an insulated wire.
For this purpose, means can be provided for restraining a portion
of the insulated wire which is to have a selective portion of
3Q insulation removed. One or more jets of water can be directed
about the insulated wire thereby circumferentially cutting the
insulation and thus enabling the removal of the selec~ed portion
of insulation.
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It may therefore be seen that the present invention
provides an improved device and method or stripping the outer
jacket ~rom the inner core of an electric cable without damagin~
the inner core and thereby allowing the inner core to be salvaged.
The device of the present invention is low in cost, has a high
de~ree of reliability, and operates at a fast speed. There are
also several distinct advantages in using a high-pressure jet of
fluid instead of other cutting instrumentalities. The device
of the present invention is ideally suited for stripping the
1~ outer insulation o an insulated wire without damaaing the inner
conductor because a high-pressure jet of fluid can easily and
quickly cut through the outer insulation while having little
effect on the inner conductor. Further, the device of the
present invention is also ideally suited for stripping the outer
jacket from the inner core of an electric cable because the
depth of the cut along the length of the cable can be accurately
controlled regardless of irregularities in the wire and the wire
transport system to prevent the jet of fluid from cutting through
the outer jacket and thereby possibly damaging the inner core.
It should be understood that although certain preferred
embodiments of the present invention have been illustrated and
described, various modifications, alternatives, and equivalents
thereof will become apparent to those skilled in the art and,
accordingly, the scope of the present invention should be defined
only by the appended claims and equivalents thereof.
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