Apparatus and Method of Removing Cable

1. Field of the Invention

The present invention relates to a method of retrieving underground cable or removing cable from conduit and more particularly, multi-conductor cable, such as telecommunication cable.

2. Description of Prior Art

During the installation process, a telecommunications cable is pressurized with air as a measure of protection. The pressurization of this cable and the settlement of the earth around it or the filling of the conduit with mud over a period of time creates friction between the cable and its surroundings which makes it difficult to remove. When the underground telecommunication cable or the cable routed in conduit is no longer in service, for example, when a communication system is being expanded when a more advanced system, such as a fiber optic system, is installed, the previous service cable is abandoned underground or within the conduit because of the cost involved in removing it.

There are methods known for removing underground cables. However, no methods currently in use incorporate the collapse of the cable or the reduction of the diameter of the cable through an evacuation process.

U.S. Pat. No. 2,297,164 issued Sep. 29, 1942 to John E. Rainwater discloses an apparatus for pulling and replacing pipes by means of a cable and a device attached to the cable whereby a pipe may be pulled and replaced.

U.S. Pat. No. 4,018,058 issued Apr. 19, 1977 to Heinrich Eichenseher et al. discloses a method of recovering non-ferrous metal conductors from a sheathed cable laid in the earth which includes excavating the earth at intervals, severing the cables, and withdrawing the cable with the aid of a pulling force.

U.S. Pat. No. 4,685,831 issued Aug. 11, 1987 to Robert L. Mahoney discloses a cable removing apparatus and a method utilizing the apparatus to remove continuous lengths of underground cable.

None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.

The present invention relates to a method of retrieving multi-conductor cable, specifically telecommunication cable, from underground or from a section of conduit. The method includes excavating the earth at intervals to expose segments of cables at these intervals. The exposed cable is severed. A cap is secured on one end of the cable to provide an airtight seal within the cable. Another cap is fastened to the opposite end of the cable also to provide an airtight seal. The second cap includes a coupling to facilitate the connection of a vacuum device. A vacuum device is connected to the cable via the coupling found on the second cap and a vacuum is applied to reduce the cross-section of the cable. Over a short period of time, the cable collapses or the cross-section is reduced from being evacuated by the vacuum device. After the evacuation process or once the cable is collapsed sufficiently, the caps are removed and a chain from a winch is fastened via a half hitch to one end of the cable. The other end of the winch is secured to an unsevered segment of cable to provide a stationary support for the winch. A pulling force is applied by the winch to remove the cable. As the cable is removed, it can be cut in lengths appropriate for transporting. As an alternative, cable is removed from conduit by severing the cable at intervals within a manhole. The same technique is applied where the cable is capped off at both ends to provide an airtight seal, the cable is collapsed by removing the air with a vacuum device, and after the cross-section is reduced sufficiently, the cable is pulled out of the conduit by a winch and if necessary, segmented for transportation purposes.

Accordingly, one object of the present invention is to provide a method of removing multi-conductor cable from the ground without the aid of heavy duty excavating equipment.

Another object of the present invention is to provide a method of removing multi-conductor cable from the ground or from a section of conduit by collapsing or reducing the cross-section of the cable by removing the air through an evacuation process.

These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.

FIG. 1 is a partially broken environmental view showing the evacuation of a severed cable in compliance with the evacuation step of the method of the present invention according to a preferred embodiment.

FIG. 2 is an environmental cross-sectional view taken along line 2--2 of FIG. 1 of the multi-conductor cable prior to the evacuation step according to the method of the present invention according to the preferred embodiment.

FIG. 3 is an environmental cross-sectional view taken along the line 3--3 in FIG. 4 of the multi-conductor cable after the evacuation step according to the method of the present invention according to the preferred embodiment.

FIG. 4 is a partially broken environmental cross-sectional view showing the pulling of the cable in compliance with the pulling step of the method of the present invention according to the preferred embodiment.

FIG. 5 is a partially broken environmental cross-sectional view showing the evacuation of a severed cable in compliance with the evacuation step of the method of the present invention according to an alternative embodiment.

FIG. 6 is an environmental cross-sectional view taken along the line 6--6 in FIG. 5 of the multi-conductor cable prior to the evacuation step according to the method of the present invention according to the alternative embodiment.

FIG. 7 is an environmental cross-sectional view taken along the line 7--7 of FIG. 8 of the multi-conductor cable after the evacuation step according to the method of the present invention according to the alternative embodiment.

FIG. 8 is a partially broken environmental cross-sectional view showing the pulling of the cable in compliance with the pulling step of the method of the present invention according to the alternative embodiment.

FIG. 9 is a block diagram of the method of the preferred embodiment of the present invention.

FIG. 10 is a block diagram of the method of the alternative embodiment of the present invention.

Similar reference characters denote corresponding features consistently throughout the attached drawings.

The present invention according to a preferred embodiment, as illustrated in FIGS. 1-4 and FIG. 9, involves a multi-conductor cable 10 partially buried in the earth 12. In agreement with the method of the present invention, the earth 12 is excavated (step 100) at intervals to expose the multi-conductor cable 10; two such intervals are illustrated by the holes 14a and 14b. The multi-conductor cable 10 exposed is severed (step 101) at points S1 and S2. The segment of the multi-conductor cable 10 to be recovered is capped at a first end 26 by a first cap 16. The first cap 16 is secured to the multi-conductor cable 10 by a hose clamp 18 to provide an airtight seal with the multi-conductor cable 10. The same segment of multi-conductor cable 10 is then capped at a second end 28 by a second cap 20 which is also secured to the multi-conductor cable 10 by a hose clamp 18 to provide and airtight seal with the multi-conductor cable 10. The second cap 20 includes a coupling 22 to facilitate the connection of a conventional vacuum device 30 (or V) via the vacuum line 24.

FIG. 2 and FIG. 9 shows the original cross-section of the multi-conductor cable 10 prior to the evacuation of air by the vacuum device (step 102). A snug fit relationship exists between the outside surface 32 of the cable 10 and the surface 34 of the earth 12 around the multi-conductor cable 10. The snug fit relationship creates friction between the multi-conductor cable 10 and the earth 12 which makes the multi-conductor cable 10 difficult to pull or to remove from the earth 12.

During the evacuation step (step 102), as shown in FIGS. 2-3 and FIG. 9, the cross-section (shown in FIG. 2) of the multi-conductor cable 10 is reduced to provide a collapsed cross-section (shown in FIG. 3) by evacuating the air 40 from the multi-conductor cable 10. After the evacuation step (step 102), a space 42 is provided which is defined by and between the outside surface 43 of the collapsed multi-conductor cable 44 and the surface 34 of the earth 12 surrounding the collapsed multi-conductor cable 44. This space 42 lessens the friction between what is now a collapsed multi-conductor cable 44 and the surface 34 of the earth 12 significantly enough to enable the collapsed multi-conductor cable 44 to be removed from the earth 12 with relative ease (step 103).

According to the preferred embodiment, as shown in FIG. 4 and FIG. 9, a chain 46 is wrapped around the collapsed multi-conductor cable 44 and secured by a half hitch 48 which tightens with tension or as the chain 46 is pulled by a conventional winch W. The first and second caps 16,20 are removed from the segment of collapsed multi-conductor cable 44; the winch W is activated to apply force in the direction F to pull to collapsed multi-conductor cable 44 from the earth 12. As the pulling step (step 103) is accomplished it may be necessary to remove and reapply the chain 46 depending on the length between the intervals or holes 14a,14b and if the collapsed multi-conductor cable 44 is to be cut into lengths suitable for transportation purposes.

An alternative embodiment, according to FIG. 5 and FIG. 10, involves a multi-conductor cable 10 in a section of conduit 52 buried beneath the earth 12. In agreement with the method of the present invention, a transition is made by the multi-conductor cable 10 within a manhole 54 from one section of conduit 52 to another section of conduit 52 whereby the multi-conductor cable 10 is exposed; two such manholes 54 are illustrated. The multi-conductor cable 10 exposed is severed at points S2 and S3 (step 200). The segment of the multi-conductor cable 10 to be recovered is capped at a first end 26 by a first cap 16. The first cap 16 is secured to the multi-conductor cable 10 by a hose clamp 18 to provide an airtight seal with the multi-conductor cable 10. The same segment of multi-conductor cable 10 is then capped at a second end 28 by a second cap 20 and is also secured to the multi-conductor cable 10 by a hose clamp 18 to provide and airtight seal with the multi-conductor cable 10. The second cap 20 includes a coupling 22 to facilitate the connection of a vacuum device 30 (or V) via the vacuum line 24.

FIG. 6 and FIG. 10 show the original cross-section 30 of the multi-conductor cable 10 prior to the evacuation step (step 100). A snug fit relationship exists between the outside surface 32 of the cable 10 and the inside surface 56 of the conduit 52 around the multi-conductor cable 10. The snug fit relationship creates friction between the multi-conductor cable 10 and the conduit 52 which makes the multi-conductor cable 10 difficult to pull or to remove from the conduit 52.

During the evacuation step (step 201), as shown in FIG. 7 and FIG. 10, the cross-section (shown in FIG. 6) of the multi-conductor cable 10 is reduced to provide a collapsed cross-section (shown in FIG. 7) by evacuating the air 40 from the multi-conductor cable 10. After the evacuation step (step 201), a space 58 is provided which is defined by and between the outside surface 43 of the collapsed multi-conductor cable 44 and the inside surface 56 of the conduit 52 surrounding the collapsed multi-conductor cable 44. This space 58 lessens the friction between what is now a collapsed multi-conductor cable 44 and the inside surface 56 of the conduit 52 significantly enough to enable the collapsed multi-conductor cable 44 to be removed from the conduit 52 with relative ease (step 202).

As shown in FIG. 8 and FIG. 10, chain 46 is wrapped around the collapsed multi-conductor cable 44 and secured by a half hitch 48 which tightens with tension or as the chain 46 is pulled by the winch W. The first and second caps 16,20 are removed from the segment of collapsed multi-conductor cable 44; the winch W is activated to apply force in the direction F to pull the collapsed multi-conductor cable 44 from the conduit 52. As the pulling step (step 201) is accomplished it may be necessary to remove and reapply the chain 46 depending on the length between the intervals or manholes 54 and if the collapsed multi-conductor cable 44 is to be cut into lengths suitable for transportation purposes.

It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.