Process and apparatus for manufacturing telecommunication cables filled with expansible powder

• US 4,419,157 A
• Filed: 09/08/1981
• Issued: 12/06/1983
• Est. Priority Date: 05/13/1980
• Status: Expired due to Fees

• Current Assignee: Industrie Pirelli Societa Per Azioni
• Original Assignee: Industrie Pirelli Societa Per Azioni
• Inventors: Ferrentino, Antonio
• Primary Examiner(s): Dawson, Robert A.
• Application Number:
  US06/300,263
• Time in Patent Office: 819 Days
• Field of Search: 156/48, 156/53, 156/56, 174/102 P, 174/116, 174/118, 141/250, 222/413, 428/377, 428/378, 57/212, 57/217, 57/295, 57/296, 57/362, 118/44, 118/DIG. 5, 118/DIG. 19, 427/117, 427/120, 427/185
• US Class Current: 156/56
• CPC Class Codes: H01B 13/321 the material being a powder
• CPC Class Codes: Y10S 118/05 Fluidized bed
• CPC Class Codes: Y10S 118/19 Wire and cord immersion
• CPC Class Codes: Y10T 428/2936 Wound or wrapped core or coating [i.e., spiral or helical]
• CPC Class Codes: Y10T 428/2938 Coating on discrete and individual rods, strands or filaments

Abstract

A process and apparatus for filling multi-conductor cables, particularly a telecommunication cable with several insulated wires surrounded by a covering and a sheath, with a mixture of powders which expand with the absorption of moisture. The conductors are fed in spaced relation into the entrance of a casing having an interior, frusto-conical wall which decreases in diameter from its entrance to its exit. The exit is small in diameter compared to the entrance so that the conductors converge as they pass from the entrance to the exit. Intermediate the entrance and the exit, the conductors are subjected to the powders which are caused to follow a helicoidal course by a screw which directs them toward the exit. Due to the shape of the casing wall, the powders are forced toward the conductors.

Claims

1. A process for manufacturing a multi-conductor, electric cable comprising a plurality of conductors bundled together, a covering over the bundled conductors, and a material expansible by the absorption of a liquid disposed between the conductors and between the conductors and the covering, said process comprising:

advancing a plurality of said conductors through a frusto-conical casing having guiding means forming a first wall at the larger diameter end and an inner frusto-conical wall, said casing having a conductor entrance in the first wall at the larger diameter end of said frusto-conical wall and a conductor exit at the smaller diameter end of said frusto-conical wall, said conductors being advanced in the direction from said entrance to said exit, being fed into said entrance in spaced relation and being maintained in spaced relation until they are brought together in converging relation at said exit whereby the conductors effectively form an open frusto-conical cage within said casing having its larger end at said entrance and its smaller end at said exit;

at a point spaced from said exit in the direction of said entrance, supplying said material in powder form to the interior of said frusto-conical wall of said casing and to the interior of said frusto-conical cage while the conductors are advanced, and within said frusto-conical wall, mechanically causing said material in powder form to flow from said point along a helicoidal course within said frusto-conical wall and in said direction in which said conductors are advanced independently of the movement of the conductors, said conductors being exposed within said frusto-conical wall to said powder supplied therewithin and said helicoidal course also being directed so as to intersect the spaced conductors within said frusto-conical wall and so as to pass between the spaced conductors within said frusto-conical wall whereby said material is directed onto and between said conductors within said frusto-conical wall and enters and fills the frusto-conical cage formed by the spaced conductors and advances therewithin and toward said exit at which the material is forced toward the axis of said casing and further penetrates between the conductors; and

when the conductors with the powder thereon and therebetween leave said exit, applying a covering thereover.

2. A process as set forth in claim 1 wherein said helicoidal course extends around said plurality of conductors and powder is diverted from said course throughout its length toward said conductors.

3. A process as set forth in claim 1 or 2 wherein said covering is applied by wrapping the conductors with tapes and applying a sheath over the wrapped tapes.

4. Apparatus for manufacturing a multi-conductor, electric cable comprising a plurality of conductors bundled together with a material expansible by absorption of liquid disposed on and between the bundled conductors, said apparatus comprising:

a frusto-conical casing having a larger diameter entrance end, a smaller diameter, exit end and a frusto-conical inner wall, a conductor entrance opening at the larger diameter end of said wall and a conductor exit opening, smaller than the entrance opening, at the smaller diameter end of said wall;

means for advancing said conductors through the cavity defined by said wall in the direction from said entrance opening to said exit opening;

guiding means for guiding said conductors in spaced relation at the entrance end of the casing for maintaining the conductors in spaced relation until they are at the exit end of the casing and for bringing the conductors into close relation at the exit end of the casing, where said conductors effectively form a frusto-conical cage within the casing having its larger end at said entrance end and its smaller end at said exit end; and

means for supplying said expansible material in powder form to the interior of said casing at a point spaced from said exit end in the direction of said entrance end and onto and between the spaced conductors within said casing, said casing being free of obstructions between said last-mentioned means and said conductors within said casing which would prevent said material in powder form from impinging upon said conductors within said casing and from passing therebetween into the cage formed within said casing by said conductors and said last-mentioned means including means within said frusto-conical inner wall of said casing for causing said expansible material in powder form to flow along a helicoical course within said frusto-conical wall from in advance of said exit opening and toward said exit opening, said helicoidal course also intersecting said conductors and passing therebetween.

5. Apparatus as set forth in claim 4 wherein said means for causing said material to flow along a helicoidal course comprises a screw within said frusto-conical inner wall with a longitudinal bore and with spaced threads around said bore having openings therebetween which extend from the exterior of the screw to said bore, said screw extending longitudinally from adjacent the exit opening to a point spaced from said exit opening in the direction of said entrance opening, said screw being rotatably mounted and said threads having a hand which causes said material to move in the direction from said entrance to said exit when the screw is rotated in one direction, said bore of said screw being sized and shaped to permit the passage of said conductors therethrough and the outer peripheries of said threads conforming and being adjacent to said wall, driving means for rotating said screw in said one direction around its longitudinal axis, and a hopper for feeding said material into said cavity at a point therein spaced from said exit opening.

6. Apparatus as set forth in claim 5 wherein said bore is frusto-conical and has its smaller and larger diameter ends respectively adjacent said exit opening and spaced from said exit opening in the direction of said entrance opening.

7. Apparatus as set forth in claim 6 wherein said driving means comprises a flange ring, mounting means rotatably mounting said ring at the entrance end of said casing, the inner diameter of said ring being a size which permits the passage of said conductors therethrough and said screw being secured at the end thereof nearest said entrance opening to said ring for rotation with the latter, and power actuated means connected to said ring for rotating said ring around the axis of said screw.

8. Apparatus as set forth in claim 4, 5 or 6 wherein said guiding means comprises a disc with a plurality of circumferentially spaced openings for the passage of the conductors through said openings.

9. Apparatus as set forth in claim 4 wherein said means for causing said expansible material to flow along a helicoidal course comprises a further casing having a frusto-conical inner wall and having an extension at the smaller diameter end of the wall thereof disposed within said cavity intermediate the entrance and exit openings of said first-mentioned casing, said extension having an exit opening directed toward the exit opening of the first-mentioned casing for directing said material toward said last-mentioned exit opening, a screw within said further casing, said screw being rotatably mounted within said inner wall of said casing, having its axis of rotation extending transversely to the axis of the frusto-conical wall of said first-mentioned casing and having exterior threads shaped to conform to the shape of said last-mentioned inner wall and to lie in close proximity to said last-mentioned inner wall, and means for feeding said material to said screw at a point thereon remote from said extension.

10. Apparatus as set forth in claim 9 wherein said guiding means comprises a disc at the entrance opening of the first-mentioned casing for maintaining the conductors in spaced relation at the entrance opening, said disc having a plurality of circumferentially spaced openings therethrough for the passage of the conductors through said openings.

11. Apparatus for manufacturing a multi-conductor, electric cable comprising a plurality of conductors bundled together with a material expansible by absorption of liquid disposed on and between the bundled conductors, said apparatus comprising:

a frusto-conical casing having a larger diameter entrance end and a frusto-conical inner wall, a conductor entrance opening at the larger diameter end of said wall and a conductor exit opening, smaller than the entrance opening, at the smaller diameter end of said wall;

means for advancing said conductors through the cavity defined by said wall in the direction from said entrance opening to said exit opening;

guiding means for guiding said conductors in spaced relation at the entrance end of the casing for maintaining the conductors in spaced relation until they are at the exit end of the casing and for bringing the conductors into close relation at the exit end of the casing; and

means for supplying said expansible material in powder form to the interior of said cavity at a point spaced from said exit in the direction of said entrance and onto and between the spaced conductors, said last-mentioned means comprising a screw within said frusto-conical inner wall of said casing for causing said expansible material in powder form to flow along a helicoidal course within said frusto-conical wall from in advance of said exit opening and toward said exit opening, said screw having a frusto-conical, longitudinal bore and with spaced threads around said bore having openings therebetween which extend from the exterior of the screw to said bore, said screw extending longitudinally from adjacent the exit opening to a point spaced from said exit opening in the direction of said entrance opening, and having the smaller and larger diameter ends of the bore respectively adjacent said exit opening and spaced from said exit opening in the direction of said entrance opening, said screw being rotatably mounted and said threads having a hand which causes said material to move in the direction from said entrance to said exit when the screw is rotated in one direction, said bore of said screw being sized and shaped to permit the passage of said conductors therethrough and the outer peripheries of said threads conforming and being adjacent to said wall, driving means for rotating said screw in said one direction around its longitudinal axis, said driving means comprising a flange ring, mounting means rotatably mounting said ring at the entrance end of said casing, the inner diameter of said ring being a size which permits the passage of said conductors therethrough and said mounting means comprising a plurality of rollers distributed around and engaging the circumference of said ring, said rollers having axes of rotation parallel to the axis of rotation of said screw and said screw being secured at the end thereof nearest said entrance opening to said ring for rotation with the latter, and power actuated means connected to said ring for rotating said ring around the axis of said screw.

12. Apparatus as set forth in claim 11 further comprising sealing means engaging said ring and said guiding means for preventing powder within said casing from exiting therefrom between said ring and said guiding means.

13. Apparatus as set forth in claim 12 wherein said guiding means has a plurality of circumferentially spaced openings therein for the passage of said conductors therethrough, said guiding means being mounted adjacent and in stationary relation to said ring, and wherein said sealing means comprises an annular gasket of elastomeric material mounted for rotation with said ring and engaging said guiding means.