(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2016/0037691 A1
`Kroush et al.
`(43) Pub. Date:
`Feb. 4, 2016
`
`US 20160037691A1
`
`(54) DISCONTINUOUS SHIELDING TAPE FOR
`DATA COMMUNICATIONS CABLE AND
`METHOD FOR MAKING THE SAME
`
`(52) U.S. Cl.
`CPC .............. H05K 9/0086 (2013.01); H0IB II/08
`(2013.01)
`
`(71) Applicant: NEXANS, PARIS (FR)
`
`(72) Inventors: Paul Kroushl, Franklin, MA (US); Paul
`Vanderlaan, New Holland, PA (US)
`
`(21) Appl. No.: 14/448,017
`
`(22) Filed:
`
`Jul. 31, 2014
`
`Publication Classification
`
`(51) Int. Cl.
`H05K 9/00
`HOB II/08
`
`(2006.01)
`(2006.01)
`
`ABSTRACT
`(57)
`A discontinuous shielding tape includes a first tape layer
`having a first width and a metallic layer disposed on the first
`tape layer having a second width. The second width of the
`metallic layer is narrower than the first width of the first tape
`layer so as to leave at least two metallic free Strips running the
`longitudinal length of the first tape layer, one on either side of
`the metal layer. The metallic layer is scored only within the
`second width of the metal layer with resultant discrete metal
`lic elements such than when the first tape layer is stretched,
`the discrete metallic elements are separated each by a gap
`creating the discontinuous shielding tape, where the two
`metallic free Strips are configured to maintain integrity of the
`first tape layer.
`
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`US 2016/0037691 A1
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`Feb. 4, 2016
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`DISCONTINUOUS SHIELDING TAPE FOR
`DATA COMMUNICATIONS CABLE AND
`METHOD FOR MAKING THE SAME
`
`RELATED APPLICATION
`0001. This application is related to pending U.S. patent
`application Ser. No. 13/779,089.
`
`BACKGROUND
`0002 1. Field of the Invention
`0003. This application relates to a shielding tape and
`method for making the same. More particularly, this applica
`tion relates to a shielding tape for LAN (Local Area Network)
`cables and method for the production of Such tapes.
`0004 2. Description of the Related Art
`0005 LAN or network type communication cables are
`typically constructed from a plurality of twisted pairs (two
`twisted insulated conductors), enclosed within a jacket. A
`typical construction includes four twisted pairs inside of a
`jacket, but many other larger pair count cables are available.
`0006 Care is taken to construct these cables in a manner to
`prevent cross talk with adjacent cables. For example, in a
`typical installation, many LAN cables may be arranged next
`to one another, and signals in the pairs from a first cable may
`cause interference or crosstalk with another pair in an adja
`cent LAN cable. In order to prevent this, the lay length or twist
`rate of the pairs in a cable is varied differently from one
`another. Additionally, when pairs in adjacent cables are run
`ning parallel to one another the cross talk can be increased so
`the pairs within a cable are twisted around one another (heli
`cally or SZ stranding) to further decrease interference. Spac
`ing elements can also be used so that the jacket is spaced apart
`from the pairs so that pairs in adjacent cables are as far away
`as possible.
`0007 Nevertheless, despite all of these features, in some
`cases, the requirements for increased bandwidth may neces
`sitate additional protection from crosstalk. One Such common
`type of protection is shielding. LAN cable shielding is usually
`in the form of a foil that is wrapped around the pairs inside the
`cable, under the jacket. This metal foil is usually wrapped
`around the assembled core of twisted pairs at or prior to
`jacketing and is constructed of Suitable metals, for example
`aluminum.
`0008 Although the shield is effective for preventing alien
`crosstalk and other external signal interferences, the shield
`must be grounded to the connector in order to meet safety
`regulations. This is a time consuming step that increases the
`cost to install the shielded cable. One typical example
`requires a drain wire to be helically coiled around the shield
`which also increases the overall cable cost.
`0009. In the prior art, there have been proposals to mitigate
`the above effect by providing a discontinuous shielding tape
`having periodic breaks in the shield. This design makes Sure
`that any signals that travel in the shield do not extend con
`tinuously from one end to the other end of the cable, obviating
`the need for grounding the shield.
`0010. However, making such a shielding tape is difficult.
`For example, one method currently used for manufacturing
`discontinuous tape is by incising the aluminum side of a
`polyester film backed aluminum tape. This tape is then
`stretched to separate the aluminum segments. Care must be
`taken to cut only the aluminum as the polyester film backing
`is used to keep the tape contiguous. The polyester film must
`
`also be kept thin due to its undesirable fuel loading and
`potential for smoke generation, However this thinness of the
`polyester backing tape results in uneven aluminum segment
`spacing separation and also makes tape breakage common
`during the manufacturing process,
`
`OBJECTS AND SUMMARY
`0011. The present arrangement overcomes the drawbacks
`of the prior art by providing a novel construction and manner
`for making the same for a discontinuous shield tape, for use
`for example in LAN cables or other such implementations.
`0012 To this end, in accordance with one embodiment, the
`present arrangement provides for a discontinuous foil shield
`having a first tape layer having a first width and a metallic
`layer disposed on the first tape layer having a second width.
`The second width of the metallic layer is narrower than the
`first width of the first tape layer so as to leave at least two
`metallic free strips running the longitudinal length of the first
`tape layer, one on either side of the metal layer.
`0013 The metallic layer is scored only within the second
`width of the metal layer with resultant discrete metallic ele
`ments such than when the first tape layer is stretched, the
`discrete metallic elements are separated each by a gap creat
`ing the discontinuous shielding tape, where the two metallic
`free strips, running the longitudinal length of the tape, are
`configured to maintain integrity of the first tape layer.
`0014. In accordance with another embodiment, the
`present arrangement provides a discontinuous shielding tape
`Includes a first tape layer having a first width and a metallic
`layer disposed on the first tape layer has a second width,
`where the second width of the metallic layer is narrower than
`the first width of the first tape layer so as to leave at least two
`metallic free strips running the longitudinal length of the first
`tape layer, one on either side of the metal layer.
`0015 The metallic layer and the first tape layer are peri
`odically punched completely through only within the second
`width of the metal layer with resultant discrete metallic ele
`ments and corresponding tape layer, Such that the discrete
`metallic elements are separated each by a full air gap created
`between the discrete metallic elements, where the two metal
`lic free Strips are configured to maintain integrity and conti
`nuity of the first tape layer.
`
`BRIEF DESCRIPTION OF THE DRAWINGS:
`0016. The present invention can be best understood
`through the following description and accompanying draw
`ings, wherein:
`0017 FIG. 1 shows a shielding tape substrate with a metal
`layer thereon, in accordance with one embodiment;
`0018 FIG. 2 shows a shielding tape substrate with a
`scored metal layer thereon, in accordance with one embodi
`ment;
`0019 FIG. 3A shows a shielding tape substrate with a
`metal layer thereon having discrete discontinuous metal seg
`ments, in accordance with one embodiment;
`0020 FIG. 3B shows a shielding tape substrate with a
`metal layer thereon having discrete discontinuous metal seg
`ments, in accordance with another embodiment;
`0021
`FIG. 4 shows a shielding tape substrate with a metal
`layer thereon having discrete discontinuous metal segments
`and upper tape layer, in accordance with one embodiment;
`and
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`0022 FIG. 5 shows a shielding tape substrate with a metal
`layer thereon having discontinuous metal segments, in accor
`dance with another embodiment.
`
`DETAILED DESCRIPTION
`0023. In one embodiment of the present arrangement as
`shown in FIG. 1, a first polyester substrate tape 10 is provided
`having a laminated metallic surface 12 thereon. Tape 10 is
`preferably made from polyester but it may be made from
`other polymers. Metal layer 12 is preferably made from an
`aluminum deposit but other metals may be used. In one pre
`ferred arrangement, tape 10 is approximately 0.003" thick
`and approximately 1.0"-1.5" wide. The associated metal layer
`12 deposited thereon is an aluminum layer approximately
`0.001"-0.002" thick and approximately 0.25" narrower than
`the width of tape 10, Such a size would be typically applied to
`a common LAN type cable having four twisted pairs. How
`ever, it is understood that the dimensions are only considered
`exemplary and other thicknesses and widths for tape 10 and
`metal layer 12 are within the contemplation of the present
`invention, depending on the desired final structure of the
`cable in which it will be used.
`0024. As shown in FIG. 1, tape 10 is constructed having a
`width that is wider than the metallic layer 12 such that tape 10
`has two metallic free segments 14a and 14b on each side of
`metallic layer 12 running the length of tape 10. According to
`the above exemplary dimensions, each Such metallic free
`segment 14a and 14b is approximately 0.125" wide on either
`side of metallic layer 12, running the entire length of tape 10.
`0025. As shown in FIG. 2, in order to make metallic layer
`12 discontinuous, metallic layer 12 is scored by means of a
`punch or scribing blade that incises across the entirety of the
`width of metallic layer 12 forming score lines 17. As a result,
`metallic layer 12 is now formed by a series of discretely
`scored metallic elements 16, which at this stage have a de
`minims separation as score lines 17 are at this stage very
`narrow. Each metallic element 16 is in the form of a triangle,
`with alternating orientation along the length of tape 10. How
`ever, it is to be understood that metallic elements 16 may have
`other shapes such as rectangles, squares etc... as desired. In
`one example, the longitudinal width along tape 10 of each
`metallic segment 16 is between 1.0"-6.0" (for triangles mea
`Sured from mid-height) however, the invention is equally
`applicable to any length metallic segments 16.
`0026. As shown in FIG. 3A, polyester tape 10 is stretched
`slightly separating metallic elements 16 of metallic layer 12
`So as to make metallic layer 12 discontinuous. The amount of
`stretching of tape 10 is preferably done so as to create gaps 22
`of approximately 0.05" and 0.125" depending on the desired
`final structure.
`0027. The metallic free edges 14a and 14b provide struc
`tural integrity to tape 10 during the scoring process, shown in
`FIG. 2. For example during scoring of the metallic layer 12
`into elements 16 it is possible that the blade or scoring mecha
`nism may damage tape 10. However, because of metallic free
`edges 14a and 14b, the scoring process does not need to
`traverse the entire width of tape 10 in order to complete score
`across metallic layer 12 to create discrete metallic elements
`16. As such, if any incidental scoring of tape 10 occurs during
`scoring of metallic layer 12, then during stretching, tape 10
`will at least have partially un-scored areas in the region of
`metallic free Zones 14a and 14b to maintain tape integrity
`throughout the stretch.
`
`0028. Another advantage of metallic free Zones 14a and
`14b is that they can help prevent the unintentional shorting of
`adjacent metallic segments 16 when the tape is applied
`around the cable core. For example, if discontinuous metallic
`segments extended all the way to the edge of a tape, when that
`tape is applied to a cable core at an angle (spiral wrapped as
`with typical shielding tape), there is the possibility that the
`edges of Such metal segments may intermittently touch,
`despite being longitudinally discontinuous, creating electri
`cal continuity due to tape edge curling or deformation during
`manufacturing or later installation. In the current design with
`foil free edges 14a and 14b, even after tape 10 is applied to a
`cable core at an angle, the discontinuous metallic elements 16
`do not touch and thus do not accidentally create a continuous
`conducting situation.
`0029. As an alternative embodiment, FIG.33 is the same
`as FIG. 3A only it shows a tape 100, with metallic layer 112
`and metal free edges 114A and 114B. In this embodiment,
`metallic elements 116 of metallic layer 112 are in the shape of
`squares or rectangles as opposed to triangles, but otherwise of
`Substantially the same dimensions.
`0030. In another embodiment, as shown in FIG. 4, a tape
`200 is provided again with metallic layer 212 and metal free
`edges 214A and 2143. In this embodiment, after tape 210 is
`stretched to form independent metallic elements 212 as
`shown above in FIG. 3, and optional second tape layer 230 is
`applied over metallic elements 216 for additional stability.
`This second tape layer 230 may be made of polyester and is
`substantially 0.0005" and 0.001" but it is not limited in these
`respects.
`0031. This second tape layer 230 also provides strength to
`the design to prevent breakage during later cable manufac
`turing processes. As noted above, accidental scoring of tape
`210 during scoring of metallic layer 212 can lead to breakage
`or at least a generally weakened tape 210 that could break
`when being applied during cable assembly. The addition of
`upper tape layer 230 adds a layer of stability to the overall
`design.
`0032. In another embodiment shown in FIG. 5, a tape 300
`is provided again with metallic layer 312 and metal free edges
`314A and 314B, In this embodiment, rather than creating
`gaps 22 through scoring and stretching as described above
`with FIGS. 2 and 3A/3B, segments 316 are formed in metallic
`layer 312 on tape 310, by completely punching through metal
`layer 312 and tape 310 (no stretching) forming segments 316
`with complete aft gaps 323 there between. Such an arrange
`ment still retains metallic free edges 314a and 314b and the
`advantages appurtenant thereto. Moreover, in this arrange
`ment, the metallic segments 316 and the underlying tape 310
`(that was not punched out) act as rungs in a ladder like
`arrangement with the longitudinally running metal free edges
`314a and 314b acting as the ladder rails. Such an arrangement
`may in Some cases have an advantage that complete punching
`of tape 310 may be accomplished with less variation as
`opposed to the prior scoring and stretching method from
`FIGS. 2 and 3A/3B depending on the various thicknesses
`dimensions and materials being used.
`0033 While only certain features of the invention have
`been illustrated and described herein, many modifications,
`Substitutions, changes or equivalents will now occur to those
`skilled in the art. It is therefore, to be understood that this
`application is intended to cover all such modifications and
`changes that fall within the true spirit of the invention.
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`What is claimed is:
`1. A discontinuous shielding tape comprising:
`a first tape layer having a first width; and
`a metallic layer disposed on said first tape layer having a
`second width,
`wherein said second width of said metallic layer is nar
`rower than said first width of said first tape layer so as to
`leave at least two metallic free strips running the longi
`tudinal length of said first tape layer, one on either side of
`said metal layer,
`wherein said metallic layer is scored only within said sec
`ond width of said metal layer with resultant discrete
`metallic elements such than when said first tape layer is
`stretched, said discrete metallic elements are separated
`each by a gap creating said discontinuous shielding tape,
`where said two metallic free strips are configured to
`maintain integrity of said first tape layer.
`2. The discontinuous shielding tape as claimed in claim 1
`wherein said first tape layer is made of polyester.
`3. The discontinuous shielding tape as claimed in claim 1,
`wherein said first tape layer is substantially 0.003" in thick
`CSS.
`4. The discontinuous shielding tape as claimed in claim 1,
`wherein said first tape layer is substantially 1.0"-1.5" in
`width.
`5. The discontinuous shielding tape as claimed in claim 1,
`wherein said metallic layer is substantially 0.001"-0.002" in
`thickness.
`6. The discontinuous shielding tape as claimed in claim 1,
`wherein said metallic layer is substantially 0.25" in width less
`than the width of said first tape layer.
`7. The discontinuous shielding tape as claimed in claim 6.
`wherein said metallic free strips on either side of said metallic
`layer are each substantially 0.125" in width.
`
`8. The discontinuous shielding tape as claimed in claim 1,
`wherein said discrete metallic elements are each separated by
`a gap that is substantial between 0.05"-0.125".
`9. The discontinuous shielding tape as claimed in claim 1,
`further comprising a second tape layer disposed over said
`metal layer.
`10. The discontinuous shielding tape as claimed in claim 9.
`wherein said second tape layer is made of polyester.
`11. The discontinuous shielding tape as claimed in claim 9.
`wherein said second tape layer is substantially between
`0.0005"-0.001" in thickness.
`12. The discontinuous shielding tape as claimed in claim 9.
`wherein said second tape layer is applied after said first tape
`layer is stretched to form said discrete metallic elements.
`13. A discontinuous shielding tape comprising:
`a first tape layer having a first width; and
`a metallic layer disposed on said first tape layer having a
`second width,
`wherein said second width of said metallic layer is nar
`rower than said first width of said first tape layer so as to
`leave at least two metallic free strips running the longi
`tudinal length of said first tape layer, one on either side of
`said metal layer,
`wherein said metallic layer and said first tape layer are
`periodically punched completely through only within
`said second width of said metal layer with resultant
`discrete metallic elements and corresponding tape layer,
`Such that said discrete metallic elements are separated
`each by a full air gap created between said discrete
`metallic elements, where said two metallic free strips are
`configured to maintain integrity and continuity of said
`first tape layer.
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