Cable with spaced helices

• US 5,834,699 A
• Filed: 09/10/1997
• Issued: 11/10/1998
• Est. Priority Date: 02/21/1996
• Status: Expired due to Term

• Current Assignee: The Whitaker Corporation (Meggitt PLC)
• Original Assignee: The Whitaker Corporation (Meggitt PLC)
• Inventors: Buck, Arthur G., Olson, Ronald A.
• Primary Examiner(s): Kincaid, Kristine L.
• Assistant Examiner(s): Nguyen, Chau N.
• Application Number:
  US08/926,913
• Time in Patent Office: 426 Days
• Field of Search: 174/36, 174/107, 174/113 R, 174/113 A, 174/113 AS, 174/113 C, 174/131 A, 174/128.1
• US Class Current: 174/113.00R
• CPC Class Codes: H01B 11/06 with means for reducing effects of electromagnetic or electrostatic disturbances, e.g. screens
• CPC Class Codes: H01B 11/08 Screens specially adapted for reducing cross-talk
• CPC Class Codes: H01B 11/1091 with screen grounding means, e.g. drain wires
• CPC Class Codes: H01B 7/041 attached to mobile objects, e.g. portable tools, elevators, mining equipment, hoisting cables
• CPC Class Codes: H01B 7/0892 incorporated in a cable of non-flat configuration

Abstract

A flexible and limp cable (1) is constructed with: an outer jacket (2) containing at least one row of adjacent insulated conductors (3) circumferentially encircling an elongated axis lengthwise of the cable (1), and conductive drain wires (4) in selected interstitial spaces along the adjacent insulated conductors (3), the insulated conductors (3) and the drain wires (4) extending helically along the axis, and a conductive membrane (7) circumferentially enclosing the insulated conductors (3) and the drain wires (4), and the membrane (7) engaging the drain wires (4).

Claims

1. An electrical cable comprising:

signal carrying insulated conductors extending side by side in a row, each of the insulated conductors being without an encircling conducting shield that would provide a coaxial cable construction,

a conductive membrane enclosing the row, the conductive membrane providing an electrical ground plane,

conductive drain wires in selected interstitial spaces along the insulated conductors,

the drain wires and the conductive membrane engaging and reducing cross talk among the insulated conductors without said encircling conducting shield on each of the insulated conductors that would provide said coaxial cable construction, and

the conductive membrane being contained within an exterior jacket,

the insulated conductors and the drain wires being wound helically along a central axis of the cable with the insulated conductors and the drain wires being free of compression against one another so as to promote their individual flexure when the cable undergoes flexure in a bend,

an electrical coupling influence between each of said helically wound drain wires and each corresponding one of said helically wound insulated conductors remaining constant along their lengths, and

the cable being flexible and limp and having freedom of movement while being connected to a medical instrument that is hand held and maneuvered for monitoring human indications.

2. An electrical cable as recited in claim 1 wherein, the conductive membrane comprises overlapping helices enclosing said row.

3. An electrical cable as recited in claim 1 wherein, the conductive membrane is cylindrical with an overlapped seam.

4. An electrical cable as recited in claim 1 and further comprising:

the number of said insulated conductors in said row corresponding to the largest number of said insulated conductors that fits along a circumferential line that passes through the diameters of said insulated conductors and that completely encircles said central axis, a gap in said row, a width of the gap on said circumferential line being narrower than each of the diameters of the insulated conductors extending side by side in the row.

5. An electrical cable as recited in claim 1 and further comprising:

at least another row of adjacent insulated conductors encircling said conductive membrane,

at least another conductive membrane circumferentially enclosing said another row, said another conductive membrane limiting movement of the adjacent insulated conductors from out of their positions in said another row, and

additional conductive drain wires in selected interstitial spaces along said adjacent insulated conductors,

said another row being laid in helices encircling the axis with said adjacent insulated conductors in said another row being side by side, the additional drain wires engaging said another conductive membrane to reduce cross talk among said adjacent insulated conductors,

the adjacent insulated conductors in said another row and said additional drain wires in said another row being wound helically over said conductive membrane with the adjacent insulated conductors and the additional drain wires being free of compression against one another and undergoing individual flexure when the cable undergoes flexure, and

said another conductive membrane being contained within said exterior jacket.

6. An electrical cable as recited in claim 5 wherein, the helices of respective said rows are laid in alternate pitch directions.

7. An electrical cable as recited in claim 5 wherein, the helices of said rows are laid in the same pitch directions.

8. An electrical cable as recited in claim 5 wherein, said another conductive membrane comprises overlapping helices enclosing said another row of said adjacent insulated conductors.

9. An electrical cable as recited in claim 5 wherein, said another conductive membrane is cylindrical with an overlapped seam.

10. An electrical cable as recited in claim 5 and further comprising:

a gap in said another row of the adjacent insulated conductors, the gap being narrower than each diameter of the adjacent insulated conductors.