US3675315A

US3675315A - Method for extracting wires from a cable bundle

Info

Publication number: US3675315A
Application number: US852283A
Authority: US
Inventors: Charles W Zebe
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1969-08-22
Filing date: 1969-08-22
Publication date: 1972-07-11
Anticipated expiration: 1989-07-11

Abstract

A method is disclosed for tracing and extracting unused crossconnection wires from a distributing frame by utilizing a tube having a detachable hollow conical head at the leading edge. One end of the dead wire or wire pair to be extracted is passed through the head and attached to a pull wire inside the tube. The head is inserted into the tube and the entire assembly is pushed along over the pull wire and the dead wire into the cable bundle until the dead wire is freed for extraction through the tube. A connection is provided on the tube for the application of pressurized air or smoke to aid in locating the leading end of the tube when an obstruction is encountered.

Description

[ July 11, 1972 [54] METHOD FOR EXTRACTING WIRES FROM A CABLE BUNDLE [72] Inventor: Charles W. Zebe, New Shrewsbury, NJ.

[73] Assignee: Bell Telephone Laboratories, Incorporated,

Murray Hill, NJ.

221 Filed: Aug.22,1969

2| Appl.No.: 852,283

3,394,449 7/ 1968 Black ..29/427 3,001,270 9/1961 Friedman... .29/241 3,110,430 11/1963 Park ..29/433 3,150,875 9/1964 Searlcs 116/1 14 3,378,628 4/1968 Gamer 174/1 12 3,555,674 1/1971 A'Leo ..29/433 Primaq- Examiner-John F. Campbell Assirram Examiner-Donald P. Rooney Arromq-R. J. Guenther and James Warren Falk ABSTRACT A method is disclosed for tracing and extracting unused crossconnection wires from a distributing frame by utilizing a tube having a detachable hollow conical head at the leading edge. One end ofthe dead wire or wire pair to be extracted is passed through the head and attached to a pull wire inside the tube. The head is inserted into the tube and the entire assembly is pushed along over the pull wire and the dead wire into the cable bundle until the dead wire is freed for extraction through the tube. A connection is provided on the tube for the application of pressurized air or smoke to aid in locating the leading end of the tube when an obstruction is encountered.

8Claims,lDrawlngFlgure NR (OR SMOKE) SOURCE P'A'TENTEDJUL 1 1 m2 INVENTOR CHARLES W. ZEBE A TTORNE Y METHOD FOR EXTRACTING WIRES FROM A CABLE BUNDLE BACKGROUND OF THE INVENTION This invention relates to a method for tracing and extracting unused conductors from a multiconductor cable bundle. While broadly applicable to any multiconductor electrical cable, the invention is described as applied to the extraction of unused cross-connection wires from a distributing frame of a telephone system.

DESCRIPTION OF THE PRIOR ART ln telephone systems large numbers of cross-connections are necessary to interconnect one piece of equipment with other pieces of equipment. These cross-connections are usually made at a central location on distributing frames. One such frame, the main distributing frame, is used to cross-connect subscriber telephone stations with associated central office switching equipment.

Whenever it is desired to rearrange the traffic usage on a particular piece of equipment, for example, when a new piece of equipment is added to the system, some of the old crossconnections must be removed and new cross-connections added. ln this situation, both ends of the old wires are removed from their respective terminals, which terminals are usually separated by a horizontal as well as a vertical distance, and an installer attempts to extract the old wires from the cross-connection cable bundle. On short wire lengths such a procedure is generally possible. More typical however, the cross-connection wires which are to be removed are buried inside the huge cable bundle and pass through one or more cable rings or support brackets. Under these conditions, the removal of the old cross-connection wires is tedious and time consuming.

One procedure followed by installers when attempting to remove dead wires from a distributing frame is to apply intermittent pressure to the end of one of the wires to be removed. A few feet away another installer fishes inside the wire bundle attempting to find the conductor that is intermittently moving. When the proper wire is located the installer pulls the loose end through the bundle. This entire procedure is repeated until the wire is finally free. To save time in the pulling operation, the free end of the wire is cut off so that the conductor being removed never exceeds a few feet in length. Accordingly, under present practices the removal of old crossconnection wires constitutes a substantial part of telephone installation costs. In addition, since the cut pieces of wire are too small to be reused they are discarded, again increasing the installation costs.

It has been found that in actual practice, in order to save installation time, the out-of-service wires have been allowed to remain in the cable bundle and additional wires have been added between the cross-connection points. After a few years of this practice the size of the cable bundle builds to such an extent that the cross-connection terminals become obscured thereby making the addition of new wires difficult.

Under certain conditions it has been found advantageous to reconnect an old existing dead conductor instead of running a new wire. However, such a procedure is usually difficult in practice since one end of the wire is usually buried somewhere inside the cable bundle and cannot be located. Therefore a need exists in the art for a procedure for tracing as well as for extracting individual wires or individual pairs of wires from a cable bundle.

Accordingly, each of the following is an object of the present invention: to simplify the tracing and extraction of unused conductors from a cable bundle; to simplify the labor procedure involved in installing and rearranging telephone connections; and to reduce the cable wastage now occurring in the installation procedure.

SUMMARY OF THE INVENTION These and other objects of the present invention are obtained by an exemplary embodiment of the invention wherein the end of a wire or a group of wires (such as a pair or a quad) to be extracted from a cable bundle is inserted into a tube having a detachable hollow conical head at the leading end. The dead wire(s) is attached to a pull wire inside the tube and tension is applied thereto. The head is inserted into the tube and the entire assembly is pushed along the dead wire into the cable bundle. The tube is forced along the wire until an ob struction is encountered. At this point pressurized air is introduced into the tube. The air passes through the tube and is heard as a hissing sound as it escapes from the leading end of the hollow head and passes through the cable bundle. The installer, aided by the sound of the escaping air, and by distance markers on the side of the tube, locates the obstructed end. frees the tube and continues the pushing procedure. When the tube has traveled a distance sumcient to reduce the coefficient of friction between the dead wire and the other wires of the cable bundle the tension on the pull wire is increased and the dead wire is pulled out of the cable bundle through the tube. The tube is then removed from the cable bundle.

The broad advantage of extracting conductors in accordance with the teaching of the present invention is the efficiency with which such conductors may be so extracted. Further, the use of a hollow tube for extracting old wires serves as a protection for other wires in the cable bundle as well as for allowing the dead wire to be removed in reusable lengths. In addition, the relative ease with which conductors may be removed using the apparatus and methods of the present invention will serve as encouragement to the installers to extract each wire as it is removed from service, thereby maintaining the cross-connection cable bundle at a workable size.

A feature of the invention resides in the sliding of a tube over a wire to be removed from a cable bundle and pushing the tube along the wire through the bundle to reduce sliding friction between the wire and the bundle.

Another feature of the invention involves the passage of pressurized air or smoke through the tube and out through the leading end for obstruction locating purposes.

A still further feature of the invention involves the removal of a conductor from a multiconductor cable bundle in a single length while maintaining the other conductors of the cable bundle free of damage.

DESCRIPTION OF THE DRAWING The foregoing objects, features and advantages as well as others of the invention will be more apparent from a detailed description of one illustrative embodiment thereof and from the following description of the drawing in which a cable extraction device is shown entering a cable bundle.

DETAILED DESCRIPTION Extraction Device As shown in the drawing, the wire extraction device consists primarily of three parts: a head 11, a tube 12, and a pull wire 15. Tube 12 is constructed in such a manner as to have an inside diameter slightly larger than the diameter of the wire to be extracted and an outside diameter sufficiently small so as to be able to pass inside a cable bundle, such as cable bundle 20. The thickness of the tube wall is determined primarily by the degree of rigidity required for insertion into and through the cable bundle. A typical tube would have dimensions on the order of 0.3 10 inches as an outside diameter and 0.250 inches as the inside diameter. Tube 12 may consist of a single length of tubing having a typical overall length of 50 feet. Spaced along the tube at regular intervals are distance markers 18 which are arranged to indicate the horizontal distance in terms of frame members as well as in conventional unit measurement. In situations where it is deemed necessary to provide a procedure for locating the leading end of an extraction device which has become obstructed somewhere inside a cable bundle, a source of air (or smoke) 17 may be introduced into tube 12 by a coupling, such as coupling 13. In the embodiment the front end of the coupling is connected to the distal end of tube 12. The distal end of coupling 13 is connected to tube 19 which tube is arranged with a seal, such as seal 14, at its distal end.

it should be noted that although tube 12 is illustrated as being a singie length of tube, tube 12 may, in fact, be constructed of short pieces of tube arranged to interlock with each other. Each section would then be added as needed. In such an arrangement, coupling 13 could be inserted into the tube at any convenient place and would not be limited to the distal end of tube 12 as illustrated.

Head 11, which is hollow, is arranged with a conical leading end 22 having a hole cut therethrough on the horizontal axis. The size of the hole is determined by the diameter of the wire to be traced and is typically on the order of 0.149 inches. Head 11 is arranged with a cylindrical collar 21 having an outside diameter slightly smaller than the inside diameter of tube 12 so that the collar may be force fitted into the tube. Collar 21 is further arranged with locking pins 31 such that when head [1 is inserted into the tube and twisted the head will mate securely with locking slot 32 in tube 12. The fullest part of the conical leading end of head 11 has a circumference exactly equal to the circumference of the tube such that when they are in interlocked position there is a smooth transition between head 11 and tube 12.

Pull wire 15 is arranged to pass entirely through tube 12 from the front end to the distal end and to pass through coupling 13, through tube 19, and out through seal 15. Pull wire 15 is further arranged with a junction point .lPl at its leading end so that the pull wire l5 may be securely attached to a wire to be removed, such as wire 10, for tension application purposes.

it should be noted at this point that although the conical head is shown detachably connectable to the tube, other arrangements can be devised. For example, a tube having a permanent conical shaped leading end could be arranged with a slot on the side for facilitating the connection of the pull wire to the wire to be removed.

Method of Extracting a Wire When it is desired to extract a wire, such as wire 10, from a cable bundle, such as cable bundle 20, the wire is inserted through the hole in the conical end of head 11. Accordingly, wire is then connected to the front end of pull wire at junction point JPl. Head U is then inserted into tube 12 and locked by pin and

slot assembly

31 and 32. Tension is then applied to pull wire 15 at the far end thereby pulling wire it] tight. The tube and head assembly is then pushed along the wire 10 into cable bundle thereby effectively tracing the wire [0. The tube is forced along wire 10 until an obstruction is encountered and the tube can be pushed no farther.

At this point pressurized air (or smoke, or a combination of both) is introduced into the tube from air (or smoke) source 17 and coupling 13. Seai l4 prevents the air from passing out of the distal end of the tube. Accordingly, the air passes through the tube and is heard as a hissing sound as it escapes from the leading end of the hollow head and passes through the cable bundle. An installer, aided by the sound of the escaping air and by the distance markers on the tube, locates the obstructed end, frees the tube and continues the pushing procedure until the far end of wire 10 is located.

In situations where it is desired to remove wire 10 from cable bundle 20, tube 12 is pushed along wire 10 a distance sufficient to reduce the coefficient of friction between wire 10 and the other wires of the cable bundle. At that point the tension on pull wire 15 is increased and wire 10 is pulled through head 11 and tube 12 out of cable bundle 20. Tube 12 is then removed from cable bundle 20.

In one embodiment of the invention the head was constructed of brass with a wire hole of 0. I49 inches and a conical length of I25 inches. The overall length of the head, including the collar, was 1.75 inches. The tube consisted of 50 feet of teflon flexible tubing, type P'TFE, having an inside diameter of 0.250 inches and a wall thickness of 0.030 inches. The outside diameter of the tube was 0.310 inches. The pull wire was 0.046 inches.

Conclusion While the procedure and apparatus of the invention have been shown in a particular embodiment wherein unused crossconnection wires are extracted from a cable bundle, it is to be understood that such an embodiment is intended only to be illustrative of the present invention and numerous other procedures may be devised by those skilled in the art without departing from the spirit and scope of the invention.

I claim:

1. A method of tracing wires in a wire bundle comprising the steps of inserting one end of a wire to be traced into a tube; applying tension to said inserted wire; inserting said tube inside a wire bundle; pushing said tube along said wire inside said wire bundle whereby said friction around said wire is reduced; and

increasing said applied tension on a traced wire an amount sufficient to extract said traced wire from said wire bun dle through said tube.

2. The invention set forth in claim 1 wherein said tension is applied by a wire extending through said tube.

3. The invention set forth in claim 1 wherein said tube has a conical shaped leading end detachably affixed thereto.

4. In a telephone system cross-connection distributing frame having a multiconductor cable for interconnecting various terminals;

a method for tracing or extracting unused conductors comprising the steps of inserting one end of a conductor to be traced or extracted into a tube having a conical shaped leading end;

attaching said conductor end to a wire extending through said tube;

applying tension to said wire;

pushing said tube along said inserted conductor inside said multiconductor cable;

periodically observing the progress of said tube along said conductor;

continuing said pushing and said observing steps until said tube has progressed along said conductor a distance sufficient to allow said conductor to be extracted from said multiconductor cable through said tube.

5. The invention set forth in claim 4 further comprising the step of increasing said tension on said wire an amount sufficient to pull said conductor through said tube.

6. The invention set forth in claim 4 wherein said observing step comprises the steps of applying pressurized air to the inside of said tube; and

determining where said air escapes from the leading end of said tube and passes through said multiconductor cable.

8. The invention set forth in claim 6 wherein said conical leading end of said tube is detachable from said tube.

8. A method of removing wires from a cable bundle comprising the steps of locating a free end of a wire to be removed;

inserting said free end of said wire through a conical end of a hollow cylinder;

attaching said inserted wire to one end of a pull wire extending through a tube;

coupling said cylinder to said tube;

applying tension to the other end of said pull wire;

pushing said coupled cylinder and tube assembly along said inserted wire inside said cable bundle until the forward progress of said assembly becomes obstructed; connecting said tube to a source of pressurized air; observing where said air escapes from said conical end of said hollow cylinder and passes through said cable bundle;

opening said cable bundle at said observed area and freeing said obstruction;

repeating said pushing, connecting, observing and opening steps until said assembly has traversed a distance sufficient to allow said wire to be removed from said cable 5 bundle through said assembly.

Claims

1. A method of tracing wires in a wire bundle comprising the steps of inserting one end of a wire to be traced into a tube; applying tension to said inserted wire; inserting said tube inside a wire bundle; pushing said tube along said wire inside said wire bundle whereby said friction around said wire is reduced; and increasing said applied tension on a traced wire an amount sufficient to extract said traced wire from said wire bundle through said tube.

4. In a telephone system cross-connection distributing frame having a multiconductor cable for interconnecting various terminals; a method for tracing or extracting unused conductors comprising the steps of inserting one end of a conductor to be traced or extracted into a tube having a conical shaped leading end; attaching said conductor end to a wire extending through said tube; applying tension to said wire; pushing said tube along said inserted conductor inside said multiconductor cable; periodically observing the progress of said tube along said conductor; continuing said pushing and said observing steps until said tube has progressed along said conductor a distance sufficient to allow said conductor to be extracted from said multiconductor cable through said tube.

6. The invention set forth in claim 4 wherein said observing step comprises the steps of applying pressurized air to the inside of said tube; and determining where said air escapes from the leading end of said tube and passes through said multiconductor cable.

7. The invention set forth in claim 6 wherein said conical leading end of said tube is detachable from said tube.

8. A method of removing wires from a cable bundle comprising the steps of locating a free end of a wire to be removed; inserting said free end of said wire through a conical end of a hollow cylinder; attaching said inserted wire to one end of a pull wire extending through a tube; coupling said cylinder to said tube; applying tension to the other end of said pull wire; pushing said coupled cylinder and tube assembly along said inserted wire inside said cable bundle until the forward progress of said assembly becomes obstructed; connecting said tube to a source of pressurized air; observing where said air escapes from said conical end of said hollow cylinder and passes through said cable bundle; opening said cable bundle at said observed area and freeing said obstruction; repeating said pushing, connecting, observing and opening steps until said assembly has traversed a distance sufficient to allow said wire to be removed from said cable bundle through said assembly.