Dual insulated data cable

• US 5,220,130 A
• Filed: 08/06/1991
• Issued: 06/15/1993
• Est. Priority Date: 08/06/1991
• Status: Expired due to Fees

• Current Assignee: Belden Wire & Cable Company, LLC (Belden Inc.)
• Original Assignee: Cooper Industries, Inc. (Eaton Corporation PLC.)
• Inventors: Walters, Jack
• Primary Examiner(s): NIMMO, MORRIS
• Application Number:
  US07/740,792
• Time in Patent Office: 679 Days
• Field of Search: 174/36, 174/115, 174/113 R, 174/116, 174/110 FC, 174/110 F, 174/120 SR, 174/120 R
• US Class Current: 174/36
• CPC Class Codes: H01B 11/1839 of cellular structure
• CPC Class Codes: H01B 11/1891 comprising auxiliary conductors
• CPC Class Codes: H01B 11/20 Cables having a multiplicity of coaxial lines

Abstract

Existing electrical cables (such as low speed data, low or high speed computer or telephone cables) employ connectors having holes or other openings for receiving the insulation or requiring conductors having a precise pitch. For example, a mechanical part of the connector may close over the received cables, piercing the insulation and making an electrical contact with the conductor inside the insulation. Or, the insulation may also be used to provide the spacing required for mass termination of insulation such as connectors which require a specified pitch. This dimension or pitch is supplied by the inner insulation while the outer insulation supplies the dimension required to meet the impedance/capacitance requirements of the electrical circuits involved. The modern high speed data cables must have substantially more insulation so that the capacitive loading or impedance match of the wire is at an acceptable level. With the increase in insulation, the cable does not fit into the holes or other openings of the existing connectors. The invention solves the resulting problem by providing two coaxial jackets of insulation which meets the high speed data transmission needs or extends the transmission or distance and yet the outer jacket may be stripped away so that the remaining inner jacket fits the existing connectors.

Claims

1. An electrical signal cable for use in a system for transmitting high speed data over low speed data or telephone lines, said low speed data or telephone lines having a plurality of existing connectors which make electrical contact by piercing an insulating jacket on said low speed or telephone lines, comprising an insulating polymer signal cable outer jacket, said signal cable outer jacket surrounding at least two high speed data cables and at least two power line cables and at least one ground able, each of said high speed data cables having a central conductor, an insulating non-foam polymer high speed signal jacket surrounding said central conductor, an insulating foam polymer high speed signal jacket surrounding said non-foam polymer high speed signal jacket and a metal shield means surrounding said foam polymer high speed signal jacket, said foam polymer high speed signal jacket having a larger thickness than said non-foam polymer high speed signal jacket and wherein said foam and non-foam insulation being an adequate insulation to reduce a capacitance loading between said power cables and said high speed data cables with reduction of noise being to levels which are below a level necessary for high speed data transmission, each of said power line cables having a central power line conductor and an insulating non-foam polymer power line jacket surrounding said power line conductor;

and at least one end of said signal cable having a portion of said high speed data cables and said power line cables extending beyond said signal cable outer jacket, and said high speed data cables having a stepped insulation end with said non-foam insulation high speed jacket extending beyond said foam insulation high speed jacket.

2. The signal cable of claim 1 wherein said non-foam polymer high speed jacket is sized to mechanically fit said existing connectors.

3. The cable of claim 2 wherein said non-foam high speed signal jacket is a tough nick resistance material and said foam jacket is a soft material which is easily stripped away from said non-foam high speed signal jacket.

4. The signal cable of claim 1 wherein said non-foam high speed jacket is made of a tough nick resistant material and said foam high speed jacket is made of a foam material which is easily stripped away from said inner jacket.

5. The signal cable of claim 1 wherein said non-foam high speed jacket is a fluorocarbon polymer and said foam high speed jacket is a foamed fluorocarbon polymer.

6. The signal cable of claim 4 wherein said non-foam high speed jacket is polypropylene and said foam high speed jacket is foamed polypropylene.

7. The signal cable of claim 1 wherein each of said jackets are made of a material taken from a group consisting of polyolefins and fluoropolymers.

8. The signal cable of claim 1 wherein said high speed data signal cable is manufactured in discrete lengths with a short stub of said non-foam high speed jacket being exposed at each end of said discrete length of cable.

9. A cable for use in a system for transmitting high speed data over low speed data or telephone lines, said low speed data or telephone lines having existing connectors which make electrical contact by piercing an insulating jacket on said low speed or telephone cables, said cable comprising:

a common ground;

at least one pair of power cables;

at least one pair of high speed data signal cables, each of said high speed data signal cables having

a conductor that is covered by an inner insulation jacket and an outer insulation jacket, said inner insulation is sized to mechanically fit said existing conductors and said outer insulation jacket reducing capacitive loading between said power cables and said high speed data signal cables to levels which do not interfere with said high speed data transmission, wherein said outer insulation jacket extends within a predetermined distance from one end of each of said high speed data signal cables for exposing a short stub section of said inner insulation jacket so that each of said high speed data signal cables has a stepped insulation at said one end, said inner insulation jacket is a fluorocarbon polymer, said outer insulation jacket is a foamed fluorocarbon polymer, said outer insulation jacket being covered by a shielding media;

said power cables being separated from each other by said high speed data signal cables;

an outer cable jacket that encases said common ground, said at least one pair of power cables and said at least one pair of high speed data signal cables; and

a polypropylene filler that is also encased by said outer cable jacket and which fills the interstices between said common ground, said at least one pair of power cables and said at least one pair of high speed data signal cables.

10. The cable of claim 9 wherein said shielding media is metal and covers said foam jacket of said high speed data signal cables to provide electrical shielding therefor.