It is common practice to provide cable, such as telephone, electric or other utility cables, in a network of plastic conduits buried underground. The installation of such conduits and the introduction of cables therein is obviously a time-consuming and expensive task. For any such installation, many of which extend for many miles, first the conduit must be buried underground and then the cable must be installed in the conduit. Traditionally, such cable is installed by first blowing a rope through the conduit, then attaching the cable to the rope, and then pulling the rope to insert the cable into the conduit.
Today, millions of miles of underground conduits having a cable in place exist throughout the world. However, the ever-expanding telecommunications systems often require that additional networks be put in place, networks which might even parallel an existing network. Although existing conduits are large enough to house more than one cable, because there is no known efficient way to introduce another cable into an existing conduit, another entire system of conduit must first be placed underground and a new cable installed therein. The need exists, therefore, to be able to easily and efficiently install an additional cable in an existing conduit to avoid the redundancy of multiple complete conduit/cable networks, without damage to the cable already in the conduit.
USPTO Backgrounds
USPTO Backgrounds