Apparatus for identification of need to replace synthetic fiber ropes

• US 6,247,359 B1
• Filed: 11/24/1999
• Issued: 06/19/2001
• Est. Priority Date: 12/07/1998
• Status: Expired due to Term

• Current Assignee: De Regt Germany GmbH
• Original Assignee: Inventio AG (Schindler Holding AG)
• Inventors: De Angelis, Claudio
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US09/449,332
• Time in Patent Office: 573 Days
• Field of Search: 737/62, 738/47, 738/624.9, 731/58
• US Class Current: 73/158
• CPC Class Codes: D07B 1/025 comprising high modulus, or high tenacity, polymer filaments or fibres, e.g. liquid-crystal polymers
• CPC Class Codes: D07B 1/14 Ropes or cables with incorporated auxiliary elements, e.g. for marking, extending throughout the length of the rope or cable
• CPC Class Codes: D07B 1/145 comprising elements for indicating or detecting the rope or cable status
• CPC Class Codes: D07B 1/148 comprising marks or luminous elements
• CPC Class Codes: D07B 2201/1016 characterised by the use of different strands
• CPC Class Codes: D07B 2201/1036 nine or more strands respectively forming multiple layers
• CPC Class Codes: D07B 2201/108 Cylinder winding, i.e. S/Z or Z/S
• CPC Class Codes: D07B 2201/2074 in radial direction
• CPC Class Codes: D07B 2205/205 Aramides
• CPC Class Codes: D07B 2401/2015 Killing or avoiding twist
• CPC Class Codes: D07B 2801/10 Smallest filamentary entity of a rope or strand, i.e. wire, filament, fiber or yarn

Abstract

To identify the need for replacement of stranded synthetic fiber ropes, preferably ropes of aramide fiber, a torsionally neutral rope construction of load-bearing fiber strands is obtained by having at least two layers of strands laid together in opposite directions so that the torsional forces in the layers of strands compensate each other. If the layers of the strands become weakened by unequal amounts due to wear or external influences, when the rope is under load and running operationally it begins to twist about its longitudinal axis. The twisting of the rope can be made visible by a colored mark or strip extending along the length of the rope to indicate twisting of the rope thereby providing visual identification of the need for replacement of the rope.

Claims

1. An apparatus for identifying the need to replace a synthetic fiber rope constructed of at least two concentric layers of strands laid together and made from load-bearing aramide fiber strands, which rope has a service life dependent on the load on the rope, the two concentric layers of strands being adjacent and laid in opposite directions to each other, comprising:

an indicating device visible on an exterior surface of the rope for detecting and visually indicating a rotational position of the rope about its longitudinal axis.

2. The apparatus according to claim 1 wherein the rope has an intersheath between the adjacent concentric layers of strands.

3. The apparatus according to claim 1 wherein the two concentric layers of strands include a covering layer laid on a parallel laid rope core in a direction opposite to that of said rope core.

4. The apparatus according to claim 1 wherein said indicating device is a colored strip attached to said exterior surface and extending parallel to a longitudinal axis of the rope.

5. The apparatus according to claim 1 wherein said indicating device is a colored line on said exterior surface and extending parallel to a longitudinal axis of the rope.

6. The apparatus according to claim 1 wherein said indicating device extends parallel to a longitudinal axis of the rope along an entire length of the rope.

7. An synthetic fiber rope comprising:

at least two concentric layers of strands laid together and made from load-bearing aramide fiber strands, said layers of strands being adjacent and laid in opposite directions to each other; and

an indicating device visible on an exterior surface of the rope for detecting and visually indicating a rotational position of the rope about its longitudinal axis.

8. The apparatus according to claim 7 wherein said indicating device includes a colored line extending parallel to a longitudinal axis of the rope.