JPH0138399B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electrical shielding for cabling, and more particularly, is particularly designed for use in shielding multiple ribbon cables from electrostatic and radio frequency interference. and a unique single flexible jacket assembly.

BACKGROUND OF THE INVENTION In the past, various proposals have been made for surrounding conductors and cables with conductive shielding means to protect the conductors from contamination by bundles and electrostatic fields and by radio frequency interference. Some shielding means utilize permanently erected shielding around the conductor and cable transmission, while others require cabling to be used for maintenance operations or to add or remove conductors.
You cannot avoid the serious disadvantage of being prevented from getting close to the inside of the building. The latter requirement may be met by the use of shielding coverings with fastening means to hold the covering compactly in place, yet permitting access to the interior of the covering if necessary. Many proposals have been made. Examples of the latter type of coating may be found in plummer US Pat. Nos. 2,960,561; 3,089,915; 3,467,761; The last of these patents to be issued accommodates multiple ribbon cables and is specifically constructed to shield them as a group from electrostatic and radio frequency interference outside of the shield. However, this construction method lacks any provision for mutually shielding the individual cables within the same jacket. Moreover, the shielding proposed therein consists of a single strip of shielding that must be unraveled in order to access the cable.

SUMMARY OF THE INVENTION The present invention incorporates several ribbon cables each into a separate shielded chamber, each chamber having one side end for quick access thereto for insertion or removal of the ribbon cable. Provides a single shielding assembly specifically designed to be opened along the line. Such storage compartments are conveniently provided by an accordion pleated inner subassembly of flexible material containing or formed by a conductive shield. The pleated inner subassembly is permanently secured within an outer shielding covering consisting of a thin layer with a seam, the outer layer of the covering being pliable with an interlocking seam that can be separated. Constructed from non-conductive material. These two subassemblies are surrounded by conductive elongated strips and include a pair of conductive flat strings positioned so as to be pressed against the shield of the outer subassembly when the seam is closed. are overlapped and secured together along their adjacent side edges. This seam can be easily opened if necessary, allowing unobstructed access to the receiving compartment for the ribbon cable.

It is therefore an object of the present invention to provide a new jacket designed for an assembly involving multiple ribbon cables and having provisions for shielding each of them from each other and from electrostatic and radio frequency interference. This is the original purpose.

Another object of the present invention is to provide a slender fold for each of the multiple ribbon cables to cooperate with an outer shield subassembly with separable seams to compactly fit and isolate from electrostatic and radio frequency interference. The present invention provides a single covering with an accordion pleated internal shield subassembly.

These and other more particular objects will become apparent from a reading of the following specification and claims and considered in conjunction with the accompanying drawings to which they pertain.

Reference is now made to the drawings, which illustrate preferred embodiments of the invention. Referring more particularly to FIGS. 1 and 2, there is shown an illustrative embodiment of a single electrostatic and radio frequency interference shielding coating of the present invention, indicated generally at 10. This covering has an outer subassembly 11 and a narrowly folded and pleated inner subassembly or unit 12 suitably secured together along one of their lateral edges, as by means of a seam 13. include.

The outer subassembly 11 has a main body consisting of a flexible thin layer of an outer layer 15 of impervious, non-conductive material, such as vinyl chloride, overlaid with an inner conductive layer 16, such as aluminum foil. This outer unit has sufficient width to enclose the required number of ribbon cables. The opposite side of the outer subassembly 11 is extruded as is well known to those skilled in the art and described in detail in Sander U.S. Pat. No. 2,810,944, granted October 29, 1957. suitable easily separated fastening means such as mating seams 18 and 19 are provided. A male seam member 19 extends longitudinally of the main body and lies within the main body of the covering within a protective flap 20 which underlies both seam elements 18 and 19 when assembled together as shown in FIGS. It is preferably secured to the main body. Therefore, and in the seam closed condition, it will be observed that the conductive shield layer 16 completely surrounds the inner shield 12 as shown in FIGS. 1 and 2.

The illustrative embodiment of the inner shielding unit 12 shown in FIGS. 1 and 2 is comprised of silver coated nylon fabric or netting that is easily folded into narrow folded pleats as shown. Each pleat cooperates with adjacent pleats to form a number of shielded accommodation cells for each length of ribbon cable of the type familiar to those skilled in the cable arts. The nylon fibers have great strength to support the silver coating, making it highly conductive and highly efficient shielding. As is clearly shown in FIG. 2, the inner unit 12 has a width of each fold approximately corresponding to the inner width of the outer sheathing when closing around several ribbon cables 29, so that the inner unit 12 has a length of the single sheathing. Can be crimped in any direction.

As seen in FIG. 2, the right hand side edge of the shielding unit is placed opposite the inner surface of the protective flap 20 which is in line with that side edge. These ends are then wrapped with a U-shaped strip 30 of conductive material, such as aluminum foil. A tin-plated copper flat string 31 is then placed opposite the outer legs of the foil strip 30 so that elements 11, 12, 30 and 31
are secured together by one or more rows of strong seams 13. The foil strip 30 provides an excellent conductive path between the two shielding members 12 and 16 and the strong copper strip 31, with both ends of the copper strip connected to grounding equipment or another length of shielding. It preferably extends beyond the ends of the sheath 10 to facilitate connection to the sheath 10.

The method of utilizing the above-described shielding coating 10 will be readily apparent from the foregoing description of the details of its construction. The sheath is opened and the folded and pleated inner unit 12 is unfolded in the manner shown in FIG. Each length of ribbon cable 29 is then connected to one or more chambers 28.
The successive chambers are laterally open along opposite sides of the pleated unit 12.

Complement of Ribbon Cable 29
The unit 12 having a . The seaming tapes 18 and 19 are then closed using suitable tools well known to those skilled in the art. The protruding end 32 of the conductive flat string 31 then connects to the earth cable or shielding covering 1
Connected to terminals of adjacent parts of 0. 1 and 3, the protective flap 2
0 is below the unshielded seam members 18 and 19 and sufficiently bridges them, and the conductive flat string 31 is connected to the conductive foil 1 laminated inside the outer unit 11.
Maintain firm contact with the adjacent side edges of 6. It further supports a tight tubular shield for all the cables 29 which are mutually shielded by the narrow folded pleated units 12.

If the user needs access to any one of the cables 29, the seams 18 and 19 are opened and folded outward to expose the open side of each cable receiving compartment 28. The care operation is then carried out on any selected cable or cables without disturbing the other cables, following which the outer jacket is reclosed in a similar manner as described above.

A second illustrative embodiment of the invention, shown in FIG. 5, differs from the first embodiment only in having a laminated, shielded internal subassembly. Accordingly, the same reference symbols are used to designate the same components, distinguished by the addition of a prime sign.

The folded pleated inner shielding unit 12' is a flexible laminate formed of conductive metal foil 35 to which is adhered a non-conductive material such as plastic. The latter provides protection against rupture or damage to the foil screening, additional insulation to the ribbon cable and, importantly, between conductors of adjacent cables 29' thereby minimizing the possibility of electrostatic or other interference. Useful for several features including greater separation. In all other respects, the structure, operation, and use are the same as described above with respect to FIGS. 1-4.

Although the special radio frequency interference shielding coating for a number of ribbon cables shown and disclosed in detail herein may be sufficient to accomplish its purpose and provide the benefits mentioned above, it is It is merely illustrative of the presently preferred embodiment of the invention and no limitations are intended to the design herein or to details of construction other than as defined in the appended claims. It should be understood that this is not the case.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an illustrative embodiment of the shielding sheath of the present invention fully assembled around a plurality of ribbon cables; FIG. 2 is partially enlarged in an open position; FIG. Figure 3 is a partial perspective view of the covering shown in Figure 1 with the inner shield subassembly folded and pleated; Figure 3 is an enlarged view taken along line 3--3 of Figure 1; 4 is a partial cross-sectional view taken along line 4--4 of FIG. 3; and FIG. 5 is a cross-sectional view taken along line 4--4 of FIG. 3; and FIG. FIG. 3 is a partial cross-sectional view of a second embodiment of the invention. Explanation of symbols of main parts, 11: Outer small assembly,
12: Inner subassembly, 15: Outer shielding layer, 1
6: Inner shielding layer, 18, 19: Combination seam member, 20: Protective flap, 30: U-shaped strip, 3
1: Copper flat string, 13: Seam, 28: Small room, 2
9: Ribbon cable, 35: Conductive metal foil, 3
6: Non-conductive material.

Claims (1)

Claims: 1. In a single tubular jacket for shielding multiple ribbon cables from electrical interference: inner and outer shielding subassemblies, the inner subassembly for each ribbon cable; consisting of a flexible strip of flexible conductive material that can be folded into a number of narrow folded pleats to form a storage compartment, and the outer subassembly is attached to one side of said inner subassembly. an inner and outer subassembly, such as having one lateral edge secured at the end; a pair of separable mating seam members, bridging and underlying said seam members when assembled with each other; a seam member secured at the side edge of said outer subassembly to provide a protective flap of sufficient width; an outer subassembly comprising an outer layer of electrically conductive material; electrically connected to the electrically conductive inner subassembly and placed in contact with the electrically conductive layer of the outer subassembly when the seam member is assembled; A unitary tubular shielding covering, characterized in that it comprises: means comprising an electrically conductive flat strip secured to the outer surface of said protective flap in position. 2. A tubular shielding covering as claimed in claim 1, which is attached to and surrounds said jointly secured side edges of said inner and outer subassemblies and is connected to said flat cord and said inner and outer subassemblies. A tubular shielding covering characterized in that it comprises a U-shaped strip of electrically conductive foil providing electrically conductive passages between electrically conductive parts of the article. 3. A tubular shielding according to claim 1, wherein the electrically conductive material of the inner subassembly is laminated to a substantially flexible non-conductive material over its entire length and width. A tubular shielding covering characterized by: 4. A tubular shielding sheath according to claim 1, wherein said inner subassembly is comprised of non-conductive fibers coated with a conductive material. 5. A tubular shielding sheath according to claim 1, wherein said inner subassembly is comprised of silver coated plastic fibers. 6. In a method of providing a tubular enclosure for a plurality of ribbon cables in order to shield them from mutual electrical interference and from external electric fields and signals: each ribbon extending in the length direction of the chamber; Providing a pleated flexible strip of electrically shielding material to provide a compartment suitable for housing the cable; detachable along the side edges of the conductive foil lining and sheathing; attaching one longitudinal end of said pleated strip to one side edge of a stitched tubular covering having an outer layer of impervious, non-conductive material with mating seam means; and electrically conductive means on the outer surface of one end of the pleated strip in intimate conductive relationship with the electrically shielding material and placed in contact with the electrically conductive foil when the seam of the tubular covering is closed; A method characterized by: providing; 7 In the method described in claim 6,
A method characterized by the step of utilizing a flexible material in the pleated strip having a layer of ductile metal coated plastic mesh sandwiched between layers of non-conductive material. 8. In the method described in claim 6,
Opposite ends of the pleated strip are surrounded by a strip of foil, and the foil and a piece of flat metal string are secured to the pleated strip so that the seam connects the coated mesh to the electrical connection. A method characterized by the step of ensuring contact with.