CA1253224A - Electric cable shield - Google Patents
Electric cable shieldInfo
- Publication number
- CA1253224A CA1253224A CA000495192A CA495192A CA1253224A CA 1253224 A CA1253224 A CA 1253224A CA 000495192 A CA000495192 A CA 000495192A CA 495192 A CA495192 A CA 495192A CA 1253224 A CA1253224 A CA 1253224A
- Authority
- CA
- Canada
- Prior art keywords
- fabric sheet
- zipper closure
- zipper
- plated
- article
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- D—TEXTILES; PAPER
- D03—WEAVING
- D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
- D03D1/00—Woven fabrics designed to make specified articles
- D03D1/0035—Protective fabrics
- D03D1/0043—Protective fabrics for elongated members, i.e. sleeves
Abstract
Abstract This invention provides a wraparound tubular article for EMI/RFI shielding of electrical conductors and cables which comprises a fabric sheet which may be woven, braided or warp knitted and which has two opposing edges which are held together in the wraparound configuration by a zipper.
The fabric sheet and zipper closure are nonconductive materials which have been coated or plated with a conduc-tive metal, thereby providing electrical shielding which is of substantially uniform effectiveness around the cir-cumference of the wraparound tubular article when the zipper closure is closed. The preferred fabric sheet is a woven nylon fabric. The preferred zipper material is nylon and the preferred metal plating is silver.
The fabric sheet and zipper closure are nonconductive materials which have been coated or plated with a conduc-tive metal, thereby providing electrical shielding which is of substantially uniform effectiveness around the cir-cumference of the wraparound tubular article when the zipper closure is closed. The preferred fabric sheet is a woven nylon fabric. The preferred zipper material is nylon and the preferred metal plating is silver.
Description
-` ~25322~
Back~round__f the_Invention This invention relates to shielding of electrical con-ductors and cables from electromagnetic interference (EMI) and radio frequency interference (RFI). Electrical shielding of electrical conductors and cables has conven-tionally been provided by a wire overbraid. It is desirable, however, to have a wraparound shield which can be installed on electrical conduct:ors or cables after the conductors or cables have been connected to equipment, such as computer components. Typical of the state of the art of wraparound EMI/~FI shielding devices and articles are U.S. patents 3,423,515 to Eichberg and 4,409,427 to Plummer. A common element in these wraparound shields is the presence of a metal foil layer to provide or assist in providing the EMI/RFI electical shielding. While the foil is initially effective, foil develops cracks and separa-tions upon flexing of the cable and will permit electrical leak paths during use. Another common element in these shielding articles is the overlapping of flaps of the con-ductive shielding material, such as the foil or the silvercoated fabric used in Plummer. The problem encountered with overlapping flaps of the conductive shielding material is that the overlapping portion of the flaps must be kept in tight, continuous contact in order to provide effective shielding. As with the foil shielding, the flexing of the cables frequently separates the overlapping flaps resulting in an E~I/RFI leak path.
Summary of the Invention This invention provides a wraparound tubular article for enclosing and electrically shielding electrical con-~ 125~Z4 ductors and cables comprising a nonconductive woven, braided, or warp knitted fabric sheet having two opposing edges and a nonconductive zipper closure attached to said opposing edges and adapted for holding the woven fabric sheet in a tubular configuration around an electrical con-ductor or cable wherein the woven fabric and zipper clo-sure are coated or plated with a conductive metal to thereby provide electrical shielding which is of substan-tially uniform effectiveness arouncl the circumference of the wraparound tubular article when the zipper closure is closed.
This invention also provides methods of making the wraparound tubular article described above. One method of making said article comprises weaving, braiding, or warp knitting a fabric sheet from a fiber which is coated or plated with a conductive metal and attaching to opposing edges of the fabric sheet a zipper closure which has been plated or coated with a conductive metal such that the fabric sheet and the zipper closure provide electrical shielding which is of substantially unifor~ effectiveness around the circumference of the tubular article when the zipper closure is closed.
Another method of forming the wraparound tubular article of this invention comprises coating or plating a woven, braided, or warp knitted fabric sheet of nonconduc-tive fiber with a conductive metal and attaching to the opposing edges of the coated or plated fabric sheet a ~ipper closure which has been coated or plated with a con-ductive metal to thereby provide electrical shielding which is of substantially uniform effectiveness around the circumference of the wraparound tubular article when the zipper closure is closed.
~ S3;~
Another preferred method of making the wraparound tubular article described above comprises attaching a zipper closure to opposing edges of a woven, braided, or warp knitted fabric sheet and plating or coating the assembled fabric sheet/zipper closure article with a con-ductive metal to thereby provide electrical shielding which is of substantially uniform effectiveness around the circumference of the wraparound tubular article when the zipper closure is closed.
Brief Description of the Drawinqs Figure la is an illustration of the wraparound tubular article of this invention.
Figure lb is a detail of the ground strap or drain wire which is partially pleated.
Figure 2 shows in graphic form the shielding effec-tiveness of a wraparound tubular article according to this invention on a flat 50 conductor ribbon cable tested in accordance with I.A.W. MIL-STD-285.
Figure 3 in graphic form shows the comparable shielding effectiveness of a conventional cable with wire overbraid.
Figure 4 shows in graphic form the shielding effec-tiveness of a wraparound tubular article of this invention as tested on a triaxial method coaxial line test.
Figure 5 shows in graphic form the shielding effec-tiveness of a wraparound tubular article of this invention as tested on a triaxial method coaxial line test.
-- ~ZS3~24 Description of the Invention Figure la illustrates the wraparound tubular article of this invention. Fabric sheet L has zipper closure 2 to attach to opposing edges of the ft~bric sheet along lines 3. The wraparound tubular article optionally contains a metalic ground strap or drain wire 4 for connecting the wraparound tubular article to grounding means.
1~- Figure lb is a detail of the ground strap or drain wire 4 which is woven in fabric sheet 1, except where it is pleated at area 5. The pleated portion allows the drain wire to be extended from the end of the tubular article and connected to a grounding means.
The fabric sheet may be woven, braided, or warp knitted. When a warp knitted fabric is used, the wales must run longitudinally the length of the wraparound tubu-S;~24 lar article. Braided or warp knitted fabrics may be tubu-lar which are then split when the zipper closure is attached. The braided or warp knitted fabric may be a flat sheet to which the zipper closure is attached to opposing edges.
The preferred fabric for the article of this invention is a woven fabric wherein the warp strands are longitudi-nal along the length of the wraparound tubular article and the filling runs across the fabric and consequently around the circumference of the wraparound tubular article when the zipper closure is closed. It is believed that warp strands along the length of the wraparound tubular article provide the most direct and straight path to grounding.
While the braided and warp knitted fabrics can provide ~
relatively direct path to grounding, the woven fabric is preferred.
The zipper closure may be any conventional interlocking slide fastener with sufficient tape on the edges thereof for uniformly effective attachment to the edges of the fabric sheet. ~he interlocking elements of the zipper may be spirals or other type of interlocking elements. The zipper closure may be the conventional visible type closure or may be a concealed type zipper that is not visible from the outside of the wraparound tubular article when the zipper is closed.
The materials used for the fabric sheet and for the zipper closure are nonconductive materials, such as various plastics. While not necessary, it is preferred in general that the fabric sheet and the zipper material be the same in order to provide enhanced uniform shielding -6- -~Z~3~2~
characteristics. The fabric sheet and the zipper closure may be made of nylon, polyester and similar synthetic or plastic materials. These materia:Ls can be used for the fabric sheet, the tape edges of the zipper closure and the teeth or interlocking elements of the zipper closure such that the entire wraparound tubular article of this inven-tion would be of one uniform material, such as polyester or nylon. The preferred material for the fabric sheet, the zipper tape and the zipper interlocking elements is nylon.
The selection of the nonconductive fabric and zipper materials and the conductive metal coating or plating will de~end on the shielding and other physical properties desired. The conductive metal used may be a combination of metals and will be selected according to its ability to plate or coat the fabric/zipper material and according to the shielding effectiveness on that material. The yarns in the fabric may be multifilament or monofilament. The texture of the weave, braid or ~arp knit can vary depending on the material used, the metal used and the frequencies at which the shielding i9 desired.
It has been found that the amount of conductive metal plated or coated on the fabric and zipper directly affects the shielding effectiveness. The amount of metal used will depend on the material of the fabric and zipper~ the texture of the fabric, the type of zipper and the frequen-cies at which the shielding is desired. The amount of metal used will also depend on the shielding effectiveness desired, the conductivity of the metal as well as the costof the metal. In general, the amount of metal should be at least about 8~ by weight based on the total weight of ~3~
the metal plated or coated fabric/zipper article. Maximum effec-tiveness in shielding is generally provided at about 16~. As shown in the Examples below, silver on nylon is effective at the frequencies shown in the Figures at about 10% to 13%.
The conductive metal coating or plating applied to the fabric sheet and the zipper closure may be silver, copper, nickel, and the like and the methods of plating or coat~ng the conductive metal on the fabric sheet and the zipper closure may be any suitable method known in the art. Such methods of plating or coating are illustrated by U.S. patents 3,733,213 to Jacob, 3,877,965 to Broadbent et al and 4,2~7,596 to Yee. The method of plating or coating the conductive metal on the fabric sheet and the zipper closure will depend on the material used in the fabric sheet and the zipper closure as well as on the conductive metal employed. The amount of conductive metal plated or coated on the fabric sheet and zipper closure will depend on the shielding properties desired. In general, it has been found that very thin layers of the metal coating or plating provide effective shield-ing over a broad range of frequencies. A preferred conductivemetal is silver plated or coated on nylon in accordance with the Broadbent et al disclosure.
The zipper closure may be attached to the fabric sheet edges by any effective means, such as sewing, welding or attach-ing with an adhesive. When attached by sewing or with an adhe-sive, the attachment should be made such that the metal plating or coating will provide uniform effectiveness o~ the shielding along the attachment line. The ~5~2~
preferred method of attaching the zipper closure to the fabric sheet edge is by fusion or welding with an ultraso-nic welder. This method assures uniform and complete con-tact between the zipper closure tape and the edge of the fabric sheet which can then be uniformly coated or plated with the conductive metal to provide uniform effectiveness in shielding.
As described above, the methods of making the wra-paround tubular article of this invention may be performed in a number of alternative ways. A fiber or yarn which has been plated or coated with the conductive metal may be woven, braided, or warp knitted into the fabric sheet and then attached to a zipper closure which has been coated or plated with the conductive metal. Alternatively, the woven, braided, or warp knitted fabric sheet can be plated or coated with the conductive metal and attached to the zipper closure which has been also plated or coated with the conductive metal. In another alternative, the woven, braided, or warp knitted Eabric sheet can be attached to the zipper closure and then the entire article plated or coated with the conductive metal. For economic reasons and for the most uniform final product, it is generally preferred to attach the zipper closure to the fabric sheet and then plate or coat the assembled article with the con-ductive metal.
As an additional element in the wraparound tubular article of this invention, a metal drain wire or grounding strap may be included as one of the warp strands in the woven Eabric or as a longintudinal laid-in strand in the braided or warp knitted fabric in order to facilitate the connection and grounding of the tubular article at either ~2S3~Z~
g or both endsO In addition, the grounding strap or drain wire may be pleated in the fabric sheet to create extra length at any point, such that when the wraparound tubular article is cut to the desired length, the metal grounding strap or drain wire can be extended from the length of the wraparound tubular article to facilitate connection of the grounding strap or wire to a grounding means at either end or both ends. It is preferred that tin plated copper stranded wire be used as the grounding strap. It is further preferred that the grounding strap or wire be pleated at intervals. For example, the tin plated copper stranded wire can be alternately woven in the fabric for a number of picks then the end is dropped for a number of picks where the drain wire is floated on the inside of the wraparound then it is picked up and woven in again for a number of picks, etc., over the length of the wraparound article. When this configuration is used, it is desirable to use a concurrent warp strand of the fiber or yarn to weave in the fabric at those picks where the wire is floated and not woven into the fabric, thus providing a solid fabric with no open holes in the fabric where the wire is floated. Any ratio of picks where the drain wire is woven in the picks where it is floated may be used, e.g. 60 picks woven with the drain wire in and 20 picks woven with the drain wire end out where the drain wire is floated. When the fabric is subsequently heat set and shrunk down the floated portions of the drain wire on the inside of the wraparound are consequently pleated.
The wraparound tubular article of this invention pro-vides in a very simple construction and form effective EMI/RFI shielding without the necessity of overlapping flaps of the fabric or other conductive material such as a foil. The zipper closure when coated or plated as described above provides effective shielding along the closure line. The wraparound articles of this invention may be adaptable to any size cable and any configuration of cables such as round or flat ribbon cable. In addi-tion, the articles of this invention are particularly adaptable to irregular shaped cables or multiple cable bundles. The tubular article of this invention may be supplied in a continuous roll which is cut to any desired 10 length and closed around the cable or cable bundle with a separate slider tool such as those known in the art and illustrated in U.S. patents 1,452,372 to Gomez or 4,027,369 to Kando et al.
E~ample 1 As an illustration of the effectiveness of the article of this invention, a wraparound tubular shield was made from a nylon fabric having 2000 denier multifilament warp yarn and 8 mil monofilament weft yarn. The zipper was a size 6 chain, 3/4 inch overall width, all nylon zipper available from American Robbin. The fabric sheet and zipper were separately plated with silver using the Broadbent et al. method to 11~ by weight silver based on the weight of the finished plated article. The plated ~ipper was ultrasonically welded to the plated fabric.
The wraparound shielding closure was then placed around a
Back~round__f the_Invention This invention relates to shielding of electrical con-ductors and cables from electromagnetic interference (EMI) and radio frequency interference (RFI). Electrical shielding of electrical conductors and cables has conven-tionally been provided by a wire overbraid. It is desirable, however, to have a wraparound shield which can be installed on electrical conduct:ors or cables after the conductors or cables have been connected to equipment, such as computer components. Typical of the state of the art of wraparound EMI/~FI shielding devices and articles are U.S. patents 3,423,515 to Eichberg and 4,409,427 to Plummer. A common element in these wraparound shields is the presence of a metal foil layer to provide or assist in providing the EMI/RFI electical shielding. While the foil is initially effective, foil develops cracks and separa-tions upon flexing of the cable and will permit electrical leak paths during use. Another common element in these shielding articles is the overlapping of flaps of the con-ductive shielding material, such as the foil or the silvercoated fabric used in Plummer. The problem encountered with overlapping flaps of the conductive shielding material is that the overlapping portion of the flaps must be kept in tight, continuous contact in order to provide effective shielding. As with the foil shielding, the flexing of the cables frequently separates the overlapping flaps resulting in an E~I/RFI leak path.
Summary of the Invention This invention provides a wraparound tubular article for enclosing and electrically shielding electrical con-~ 125~Z4 ductors and cables comprising a nonconductive woven, braided, or warp knitted fabric sheet having two opposing edges and a nonconductive zipper closure attached to said opposing edges and adapted for holding the woven fabric sheet in a tubular configuration around an electrical con-ductor or cable wherein the woven fabric and zipper clo-sure are coated or plated with a conductive metal to thereby provide electrical shielding which is of substan-tially uniform effectiveness arouncl the circumference of the wraparound tubular article when the zipper closure is closed.
This invention also provides methods of making the wraparound tubular article described above. One method of making said article comprises weaving, braiding, or warp knitting a fabric sheet from a fiber which is coated or plated with a conductive metal and attaching to opposing edges of the fabric sheet a zipper closure which has been plated or coated with a conductive metal such that the fabric sheet and the zipper closure provide electrical shielding which is of substantially unifor~ effectiveness around the circumference of the tubular article when the zipper closure is closed.
Another method of forming the wraparound tubular article of this invention comprises coating or plating a woven, braided, or warp knitted fabric sheet of nonconduc-tive fiber with a conductive metal and attaching to the opposing edges of the coated or plated fabric sheet a ~ipper closure which has been coated or plated with a con-ductive metal to thereby provide electrical shielding which is of substantially uniform effectiveness around the circumference of the wraparound tubular article when the zipper closure is closed.
~ S3;~
Another preferred method of making the wraparound tubular article described above comprises attaching a zipper closure to opposing edges of a woven, braided, or warp knitted fabric sheet and plating or coating the assembled fabric sheet/zipper closure article with a con-ductive metal to thereby provide electrical shielding which is of substantially uniform effectiveness around the circumference of the wraparound tubular article when the zipper closure is closed.
Brief Description of the Drawinqs Figure la is an illustration of the wraparound tubular article of this invention.
Figure lb is a detail of the ground strap or drain wire which is partially pleated.
Figure 2 shows in graphic form the shielding effec-tiveness of a wraparound tubular article according to this invention on a flat 50 conductor ribbon cable tested in accordance with I.A.W. MIL-STD-285.
Figure 3 in graphic form shows the comparable shielding effectiveness of a conventional cable with wire overbraid.
Figure 4 shows in graphic form the shielding effec-tiveness of a wraparound tubular article of this invention as tested on a triaxial method coaxial line test.
Figure 5 shows in graphic form the shielding effec-tiveness of a wraparound tubular article of this invention as tested on a triaxial method coaxial line test.
-- ~ZS3~24 Description of the Invention Figure la illustrates the wraparound tubular article of this invention. Fabric sheet L has zipper closure 2 to attach to opposing edges of the ft~bric sheet along lines 3. The wraparound tubular article optionally contains a metalic ground strap or drain wire 4 for connecting the wraparound tubular article to grounding means.
1~- Figure lb is a detail of the ground strap or drain wire 4 which is woven in fabric sheet 1, except where it is pleated at area 5. The pleated portion allows the drain wire to be extended from the end of the tubular article and connected to a grounding means.
The fabric sheet may be woven, braided, or warp knitted. When a warp knitted fabric is used, the wales must run longitudinally the length of the wraparound tubu-S;~24 lar article. Braided or warp knitted fabrics may be tubu-lar which are then split when the zipper closure is attached. The braided or warp knitted fabric may be a flat sheet to which the zipper closure is attached to opposing edges.
The preferred fabric for the article of this invention is a woven fabric wherein the warp strands are longitudi-nal along the length of the wraparound tubular article and the filling runs across the fabric and consequently around the circumference of the wraparound tubular article when the zipper closure is closed. It is believed that warp strands along the length of the wraparound tubular article provide the most direct and straight path to grounding.
While the braided and warp knitted fabrics can provide ~
relatively direct path to grounding, the woven fabric is preferred.
The zipper closure may be any conventional interlocking slide fastener with sufficient tape on the edges thereof for uniformly effective attachment to the edges of the fabric sheet. ~he interlocking elements of the zipper may be spirals or other type of interlocking elements. The zipper closure may be the conventional visible type closure or may be a concealed type zipper that is not visible from the outside of the wraparound tubular article when the zipper is closed.
The materials used for the fabric sheet and for the zipper closure are nonconductive materials, such as various plastics. While not necessary, it is preferred in general that the fabric sheet and the zipper material be the same in order to provide enhanced uniform shielding -6- -~Z~3~2~
characteristics. The fabric sheet and the zipper closure may be made of nylon, polyester and similar synthetic or plastic materials. These materia:Ls can be used for the fabric sheet, the tape edges of the zipper closure and the teeth or interlocking elements of the zipper closure such that the entire wraparound tubular article of this inven-tion would be of one uniform material, such as polyester or nylon. The preferred material for the fabric sheet, the zipper tape and the zipper interlocking elements is nylon.
The selection of the nonconductive fabric and zipper materials and the conductive metal coating or plating will de~end on the shielding and other physical properties desired. The conductive metal used may be a combination of metals and will be selected according to its ability to plate or coat the fabric/zipper material and according to the shielding effectiveness on that material. The yarns in the fabric may be multifilament or monofilament. The texture of the weave, braid or ~arp knit can vary depending on the material used, the metal used and the frequencies at which the shielding i9 desired.
It has been found that the amount of conductive metal plated or coated on the fabric and zipper directly affects the shielding effectiveness. The amount of metal used will depend on the material of the fabric and zipper~ the texture of the fabric, the type of zipper and the frequen-cies at which the shielding is desired. The amount of metal used will also depend on the shielding effectiveness desired, the conductivity of the metal as well as the costof the metal. In general, the amount of metal should be at least about 8~ by weight based on the total weight of ~3~
the metal plated or coated fabric/zipper article. Maximum effec-tiveness in shielding is generally provided at about 16~. As shown in the Examples below, silver on nylon is effective at the frequencies shown in the Figures at about 10% to 13%.
The conductive metal coating or plating applied to the fabric sheet and the zipper closure may be silver, copper, nickel, and the like and the methods of plating or coat~ng the conductive metal on the fabric sheet and the zipper closure may be any suitable method known in the art. Such methods of plating or coating are illustrated by U.S. patents 3,733,213 to Jacob, 3,877,965 to Broadbent et al and 4,2~7,596 to Yee. The method of plating or coating the conductive metal on the fabric sheet and the zipper closure will depend on the material used in the fabric sheet and the zipper closure as well as on the conductive metal employed. The amount of conductive metal plated or coated on the fabric sheet and zipper closure will depend on the shielding properties desired. In general, it has been found that very thin layers of the metal coating or plating provide effective shield-ing over a broad range of frequencies. A preferred conductivemetal is silver plated or coated on nylon in accordance with the Broadbent et al disclosure.
The zipper closure may be attached to the fabric sheet edges by any effective means, such as sewing, welding or attach-ing with an adhesive. When attached by sewing or with an adhe-sive, the attachment should be made such that the metal plating or coating will provide uniform effectiveness o~ the shielding along the attachment line. The ~5~2~
preferred method of attaching the zipper closure to the fabric sheet edge is by fusion or welding with an ultraso-nic welder. This method assures uniform and complete con-tact between the zipper closure tape and the edge of the fabric sheet which can then be uniformly coated or plated with the conductive metal to provide uniform effectiveness in shielding.
As described above, the methods of making the wra-paround tubular article of this invention may be performed in a number of alternative ways. A fiber or yarn which has been plated or coated with the conductive metal may be woven, braided, or warp knitted into the fabric sheet and then attached to a zipper closure which has been coated or plated with the conductive metal. Alternatively, the woven, braided, or warp knitted fabric sheet can be plated or coated with the conductive metal and attached to the zipper closure which has been also plated or coated with the conductive metal. In another alternative, the woven, braided, or warp knitted Eabric sheet can be attached to the zipper closure and then the entire article plated or coated with the conductive metal. For economic reasons and for the most uniform final product, it is generally preferred to attach the zipper closure to the fabric sheet and then plate or coat the assembled article with the con-ductive metal.
As an additional element in the wraparound tubular article of this invention, a metal drain wire or grounding strap may be included as one of the warp strands in the woven Eabric or as a longintudinal laid-in strand in the braided or warp knitted fabric in order to facilitate the connection and grounding of the tubular article at either ~2S3~Z~
g or both endsO In addition, the grounding strap or drain wire may be pleated in the fabric sheet to create extra length at any point, such that when the wraparound tubular article is cut to the desired length, the metal grounding strap or drain wire can be extended from the length of the wraparound tubular article to facilitate connection of the grounding strap or wire to a grounding means at either end or both ends. It is preferred that tin plated copper stranded wire be used as the grounding strap. It is further preferred that the grounding strap or wire be pleated at intervals. For example, the tin plated copper stranded wire can be alternately woven in the fabric for a number of picks then the end is dropped for a number of picks where the drain wire is floated on the inside of the wraparound then it is picked up and woven in again for a number of picks, etc., over the length of the wraparound article. When this configuration is used, it is desirable to use a concurrent warp strand of the fiber or yarn to weave in the fabric at those picks where the wire is floated and not woven into the fabric, thus providing a solid fabric with no open holes in the fabric where the wire is floated. Any ratio of picks where the drain wire is woven in the picks where it is floated may be used, e.g. 60 picks woven with the drain wire in and 20 picks woven with the drain wire end out where the drain wire is floated. When the fabric is subsequently heat set and shrunk down the floated portions of the drain wire on the inside of the wraparound are consequently pleated.
The wraparound tubular article of this invention pro-vides in a very simple construction and form effective EMI/RFI shielding without the necessity of overlapping flaps of the fabric or other conductive material such as a foil. The zipper closure when coated or plated as described above provides effective shielding along the closure line. The wraparound articles of this invention may be adaptable to any size cable and any configuration of cables such as round or flat ribbon cable. In addi-tion, the articles of this invention are particularly adaptable to irregular shaped cables or multiple cable bundles. The tubular article of this invention may be supplied in a continuous roll which is cut to any desired 10 length and closed around the cable or cable bundle with a separate slider tool such as those known in the art and illustrated in U.S. patents 1,452,372 to Gomez or 4,027,369 to Kando et al.
E~ample 1 As an illustration of the effectiveness of the article of this invention, a wraparound tubular shield was made from a nylon fabric having 2000 denier multifilament warp yarn and 8 mil monofilament weft yarn. The zipper was a size 6 chain, 3/4 inch overall width, all nylon zipper available from American Robbin. The fabric sheet and zipper were separately plated with silver using the Broadbent et al. method to 11~ by weight silver based on the weight of the finished plated article. The plated ~ipper was ultrasonically welded to the plated fabric.
The wraparound shielding closure was then placed around a
2.5 inch flat 50-conductor ribbon cable and a 3-meter length of the wraparound shield was tested in accordance with I.A.W. MIL-STD-285 using the ribbon cable as receiver. The shielding effectiveness is shown in graphic form in Figure 2.
~s~
--ll--By comparison, a 3 meter length of a conventional cable shielded with overbraided wire and rated for 40dB
from 10 kilohertz to 1 gigahertz was tested under the same conditions. The shielding effectiveness of this cable is shown in graphic form in Figure 3.
Example 2 Another sample of the same plated fabric and plated zipper as Examp~e 1 assembled in the same way as Example 1 and also having 11% by weight silver on the fabric and zipper was tested using the triaxial method by measuring voltage.
The sample length was 0.5 meters and a five volt input was used. The shielding effectiveness is shown in graphic form in Figure 4.
Example 3 Another sample which was the same as Example 2, except that the silver ws 11.6%, was tested the same way as in Example 2. The shielding effectiveness i3 shown in graphic form in Figure 5.
~s~
--ll--By comparison, a 3 meter length of a conventional cable shielded with overbraided wire and rated for 40dB
from 10 kilohertz to 1 gigahertz was tested under the same conditions. The shielding effectiveness of this cable is shown in graphic form in Figure 3.
Example 2 Another sample of the same plated fabric and plated zipper as Examp~e 1 assembled in the same way as Example 1 and also having 11% by weight silver on the fabric and zipper was tested using the triaxial method by measuring voltage.
The sample length was 0.5 meters and a five volt input was used. The shielding effectiveness is shown in graphic form in Figure 4.
Example 3 Another sample which was the same as Example 2, except that the silver ws 11.6%, was tested the same way as in Example 2. The shielding effectiveness i3 shown in graphic form in Figure 5.
Claims (18)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A wraparound tubular article for enclosing and electrically shielding electrical conductors and cables comprising a nonconductive woven, braided, or warp knitted fabric sheet having two opposing edges and a nonconductive zipper closure attached to said opposing edges and adapted for holding the fabric sheet in a tubular configuration around an electrical conductor or cable wherein the woven fabric and the zipper closure are coated or plated with a conductive metal to thereby provide electrical shielding which is of substantially uniform effectiveness around the circumference of the wraparound tubular article when the zipper closure is closed.
2. The article according to Claim 1 wherein the fabric sheet is woven.
3. The article according to Claim 2 wherein the warp yarns are multifilament and the fill is monofilament.
4. The article according to Claim 1 wherein the fabric sheet is braided.
5. The article according to Claim 1 wherein the fabric sheet is warp knitted.
6. The article according to Claim 2 wherein the woven fabric is nylon.
7. The article according to Claim 6 wherein the warp yarn is multifilament and the fill is monofilament.
8. The article according to Claim 6 wherein the fabric sheet and zipper closure are coated or plated with silver.
9. The article according to Claim 8 wherein the zipper is nylon.
10. The article according to Claim 9 wherein the fabric sheet and the zipper closure are coated or plated with silver.
11. The article of Claim 2 wherein the fabric sheet con-tains a longintudinal metal grounding strand.
12. The article of Claim 11 wherein the metal grounding strand is pleated.
13. A method of making a wraparound tubular article for enclosing and electrically shielding electrical conductors and cables comprising weaving, braiding, or warp knitting a fiber or yarn which is plated or coated with a conduc-tive metal to form a fabric sheet and attaching to the opposing edges of the fabric sheet a zipper closure which is plated or coated with a conductive metal.
14. The method of Claim 13 wherein the fiber or yarn is nylon, the zipper closure is nylon and the fiber or yarn and the zipper closure are coated or plated with silver.
15. A method of making a wraparound tubular article for enclosing and electrically shielding electrical conductors and cables comprising plating or coating a woven, braided, or warp knitted fabric sheet with a conductive metal and attaching to the edges of the fabric sheet a zipper clo-sure which has been coated or plated with a conductive metal.
16. A method according to Claim 15 wherein the fabric sheet and the zipper closure are nylon and the conductive metal is silver.
17. A method of making a wraparound tubular article for enclosing and electrically shielding electrical conductors and cables comprising attaching a zipper closure to a woven, braided, or warp knitted fabric sheet and coating or plating the fabric sheet/zipper closure assembly with a conductive metal.
18. A method according to Claim 17 wherein the fabric sheet and zipper closure are nylon and the conductive metal is silver.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US67069884A | 1984-11-13 | 1984-11-13 | |
| US670,698 | 1984-11-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1253224A true CA1253224A (en) | 1989-04-25 |
Family
ID=24691495
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000495192A Expired CA1253224A (en) | 1984-11-13 | 1985-11-13 | Electric cable shield |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1253224A (en) |
-
1985
- 1985-11-13 CA CA000495192A patent/CA1253224A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry | ||
| MKEX | Expiry |
Effective date: 20060425 |