This invention relates to a duct which can be positioned in an underground conduit or buried directly in the ground, and which receives a fiberoptic cable or the like therein. More particularly, this invention relates to such a duct which can be easily installed in a conduit without spiraling, and which can have a cable positioned therein prior to the installation.
The communications industry most often utilizes underground conduits to house its communication cables, such as fiberoptic cables. Traditionally, one or more innerducts are provided in the conduit, each of which carry a cable. One such type of innerduct is constructed of a rigid high density polyethylene (HDPE). Such tubular innerducts are extruded and while still hot are put on reels which might hold as much as twenty-five hundred feet of the product. The innerduct then cools on the reel and is ready to be installed in a conduit to subsequently receive a cable therein.
However, such innerducts are fraught with problems. These innerducts have “reel memory” such that as they come off the reel to be positioned in a conduit, they will spiral during placement. Such spiraling makes it difficult to insert the innerduct, and at a later date makes it more difficult to insert a cable into the innerduct. Moreover, since most conduits are designed to receive multiple innerducts, an existing spiraling innerduct in a conduit makes it extremely difficult to place additional innerducts in the conduit.
Thus, the need exists for a rigid innerduct, made of HDPE or an equivalent material, which will not spiral upon insertion into a conduit. Moreover, the need exists to provide such an innerduct which can carry a cable prior to being installed in a conduit so that the innerduct and cable are inserted simultaneously into the conduit, and which could alternatively be inserted directly in the ground.
It is thus an object of one aspect of the present invention to provide a rigid innerduct which can be inserted into a conduit without spiraling.
It is an object of another aspect of the invention to provide a rigid innerduct, as above, which can have a cable positioned therein during its construction so that the innerduct and cable can be inserted simultaneously into a conduit.
It is an object of an additional aspect of the invention to provide a duct, as above, which could also be inserted directly in the ground as opposed to in an underground conduit.
These and other objects of the present invention, as well as the advantages thereof over existing prior art forms, which will become apparent from the description to follow, are accomplished by the improvements hereinafter described and claimed.
In general, an apparatus adapted to be inserted into a conduit or into the ground includes a sheet of a polymeric semi-rigid material having edges. Complementary connectors extend outwardly from each edge of the material such that when the connectors are attached to each other, a tubular duct is formed.
In accordance with another aspect of the invention, a duct adapted to be inserted into a conduit includes a longitudinally extending corrugated sheet of semi-rigid material, a cable, and complementary connectors extend outwardly from each lateral edge of the sheet. When the connectors are attached to each other, the duct is formed by having a cable therein.
In accordance with the method of the present invention, a duct is formed by the steps of providing a longitudinally extending polymeric sheet of material having complementary connectors at its lateral edges. A cable is placed adjacent to the material and the connectors are attached to form the duct with the cable therein.
Preferred exemplary ducts according to the concepts of the present invention which can be formed by the method of the present invention are shown by way of example in the accompanying drawings without attempting to show all the various forms and modifications in which the invention might be embodied, the invention being measured by the appended claims and not by the details of the specification.
A sheet of material is generally indicated by the numeral 10, and is preferably made of a polymeric material such as a thermoplastic, an example of which is HDPE. Thus, material 10 is a thermoplastic having sufficient rigidity to hold its shape while having sufficient flexibility to be bent into a tubular shape as will hereinafter be described. The degree of flexibility of such material depends, to some extent, on the thickness thereof. Material 10 extends longitudinally for some length, often 2500 feet or more, and it can be stored on a reel and taken to a site where it will eventually be formed into an innerduct and installed in a conduit.
A traditional HDPE innerduct I, shown in prior art
In the present invention, as shown in
To that end, complementary connectors, generally indicated by the numerals 13 and 14, extend longitudinally along the lateral edges of material 10. As somewhat schematically shown, connector 13 can be in the form of a hook or barb, and connector 14 can be in the form of a socket. Thus, connector 13 can take the shape of an arrow 15 which compresses as it passes through an opening 16 in connector 14 defined by lugs 17. Then when arrow 15 passes lugs 17, it flexes back to its original configuration to be located in cavity 18 of connector 14. Of course, other complementary connectors, such as a ball and socket configuration, a VELCRO® with a hook and loop connection, or equivalent devices, could be employed without departing from the concept of the invention.
Before connectors 13 and 14 are attached, as just described, a cable 19 can be positioned adjacent to, and generally laterally centered along, material 10 as shown in
This assembly of innerduct 20 can be accomplished at an access site of an underground conduit. To do so, a roll of cable 19 and a roll of material 10 can be supplied at the conduit introduction site. Then they are fed through a device (not shown) which can wrap the material 10 around the cable 19 as it is being pulled into the conduit by means of a pull rope already installed in the conduit. Such a device is similar to the apparatus shown in U.S. patent application Ser. No. 17/475,693 reference to which is incorporated herein for a better understanding of the manner in which innerduct 20 is assembled and inserted into a conduit. If desired, a pull tape (not shown) can be positioned adjacent to innerduct 20 and can be installed in the conduit at the same time as innerduct 20 so that it is available for installation of another innerduct into the conduit at a later date as may be desired.
As previously described, and as shown in
Another embodiment of the present invention is shown in
Like the embodiment of
Before connectors 22 and 23 are attached, as just described, a cable 28 can be positioned adjacent to, and generally laterally centered along, material 21 as shown in
Innerduct 29 may be constructed at a conduit access site in the same manner as innerduct 20, and as shown in
An additional embodiment of the present invention is shown in
Complementary connectors 31 and 32 are formed on the open ends of material 30. These connectors can also be in the form of a hook and socket combinations. Thus, connector 31 can take the shape of an arrow 33 which compresses as it passes through an opening 34 in connector 32 defined by lugs 35. Then when arrow 33 passes lugs 35, it flexes back to its original configuration to be located in cavity 36 of connectors 32. Of course, other complementary connectors, such as a ball and socket, a VELCRO® with hook and loop connection, or equivalent devices, could be employed without departing form the concept of the invention.
Before connectors 31 and 32 are attached to each other, a cable 37 can be received within material 30 by passing it through the opening between the open ends of material 30, as somewhat schematically shown in
In view of the foregoing description, it should be evident that a device constructed and used as described herein accomplishes the objects of the present invention and otherwise substantially improves the art.
This application claims priority from U.S. Provisional Patent Application Ser. No. 63/323,733 filed on Mar. 25, 2022, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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63323733 | Mar 2022 | US |