| 摘要 |
1. A multiple channel duct assembly for cables comprising: (a) a plurality of plastic inner ducts contiguous, co-directionally extending, substantially parallel, in abutting contact with each other, each of said inner ducts having the cross sectional areas sufficient to contain at least one cable; and (b) a plastic outer duct encircling said inner ducts over their entire length to retain them in their contiguous relationship; (c) wherein said outer duct has a corrugated tubular section including a plurality of contiguous ridges and troughs extending over the entire length; (d) whereby said assembly is so flexible that it can be coiled around transportable reels as well as so strong that it can withstand dirt in a trench. 2. The multiple channel duct assembly for cables of Claim 1, wherein each of said inner ducts is made of polyethylene. 3. The multiple channel duct assembly for cables of Claim 1, wherein each of said inner ducts has a substantially round cross sectional shape. 4. The multiple channel duct assembly for cables of Claim 1, wherein each of said inner ducts is made separately extruded. 5. The multiple channel duct assembly for cables of Claim 1, wherein each of said inner ducts is connected by flexible connecting webs. 6. The multiple channel duct assembly for cables of Claim 1, wherein said outer duct has a substantially round cross sectional shape. 7. The multiple channel duct assembly for cables of Claim 1, wherein said outer duct has a substantially ellipsoid cross sectional shape. 8. The multiple channel duct assembly for cables of Claim 1, wherein said outer duct has a substantially triangular cross sectional shape with round corners. 9. The multiple channel duct assembly for cables of Claim 1, wherein said outer duct has a substantially quadrangular cross sectional shape with round corners. 10. A multiple channel duct assembly for cables comprising: (a) a plurality of plastic inner ducts contiguous, co-directionally extending, substantially parallel, in abutting contact with each other, each of said inner ducts having the cross sectional areas sufficient to contain at least one cable; and (b) a plastic outer duct encircling said inner ducts over their entire length to retain them in their contiguous relationship; (c) wherein said outer duct has a corrugated tubular section including a plurality of contiguous ridges and troughs extending over the entire length, and wherein said inner ducts and said outer duct are altogether made of polyethylene; (d) whereby said assembly is so flexible that it can be coiled around transportable reels, and so strong that it can withstand dirt in a trench. 11. The multiple channel duct assembly for cables of Claim 10, wherein said inner ducts and said outer duct are welded together at the contiguous portions where the troughs of said outer duct and the outer peripheral surfaces of said inner ducts are contacted. 12. The multiple channel duct assembly for cables of Claim 10, wherein each of said inner ducts is made separately extruded. 13. The multiple channel duct assembly for cables of Claim 10, wherein each of said inner ducts is connected by flexible connecting webs. 14. The multiple channel duct assembly for cables of Claim 10, wherein the interior surfaces of said inner ducts are formed with longitudinal ridges upon which the cable ride as it pulled through them. 15. The multiple channel duct assembly for cables of Claim 10, wherein the interior surfaces of said inner ducts are formed with spiral ridges upon which the cable ride as it pulled through them. 16. The multiple channel duct assembly for cables of Claim 10, wherein the wall of said inner ducts is formed with corrugation. 17. The multiple channel duct assembly for cables of Claim 10, wherein said outer duct has a substantially round cross sectional shape. 18. The multiple channel duct assembly for cables of Claim 10, wherein said outer duct has a substantially ellipsoid cross sectional shape. 19. The multiple channel duct assembly for cables of Claim 10, wherein said outer duct has a substantially triangular cross sectional shape with round corners. 20. The multiple channel duct assembly for cables of Claim 10, wherein said outer duct has a substantially quadrangular cross sectional shape with round corners. |
