Rope pre-failure warning indicator system and method

Abstract

A pre-failure indicator system for determining a degradation or failure condition includes a rope having an elongated structural strand and a pre-failure indicator strand. The pre-failure indicator strand has a tensile strength less than a tensile strength of the structural strand. The pre-failure indicator strand constructed of a conductive wire. The pre-failure indicator strand is configured to fail when the rope is subject to tension that exceeds the tensile strength of the structural strand. An indicator generates a detectable signal when the pre-failure indicator strand fails. A transceiver detects the detectable signal. The transceiver is configured to transmit a warning upon receipt of the detectable signal.

We claim: 
     
         1 . A pre-failure indicator system for determining a degradation or failure condition, the pre-failure indicator system comprising:
 a rope having an elongated structural strand and a pre-failure indicator strand, the pre-failure indicator strand comprised of a conductive wire and configured to fail when the rope is subject to tension that is less than the tensile strength of the structural strand;   an indicator that generates a detectable signal when the pre-failure indicator strand fails; and   a transceiver that detects the detectable signal, the transceiver configured to transmit a warning upon receipt of the detectable signal.   
     
     
         2 . The pre-failure indicator system of  claim 1 , wherein the structural strand is comprised of a plurality of structural strands. 
     
     
         3 . The pre-failure indicator system of  claim 1 , wherein the conductive wire is comprised of a multiple conductive wires. 
     
     
         4 . The pre-failure indicator system of  claim 1 , wherein the conductive wire is constructed of a metal. 
     
     
         5 . The pre-failure indicator system of  claim 4 , wherein the metal is comprised of one of copper and silver. 
     
     
         6 . The pre-failure indicator system of  claim 1 , wherein the indicator includes an electrical signal generator and the detectable signal comprises an electrical signal. 
     
     
         7 . The pre-failure indicator system of  claim 1 , wherein the conductive wire is constructed one of carbon fibers and a conductive polymeric material. 
     
     
         8 . The pre-failure indicator system of  claim 1 , wherein the conductive wire includes a first end and a second end, a first terminal connected to the first end and a second terminal connected to the second end. 
     
     
         9 . The pre-failure indicator system of  claim 8 , wherein the first terminal includes a first electronic signal transmitter, a first electronic signal receiver and a first electronic signal transceiver. 
     
     
         10 . The pre-failure indicator system of  claim 1 , wherein the conductive wire is constructed of a material designed and configured to degrade at a faster rate than the structural strand based on exposure an environmental factor, the environmental factor selected from the group consisting of ultraviolet radiation, abrasion and dry rot. 
     
     
         11 . The pre-failure indicator system of  claim 1 , further comprising:
 a time-domain reflectometry (“TDR”) device associated with a first terminal of the rope, the TDR device configured to send a pulse signal into the pre-failure indicator strand and sense a time until a return pulse is received at the TDR device, the time being recorded.   
     
     
         12 . A pre-failure indicator system for determining a degradation or failure condition, the pre-failure indicator system comprising:
 a multiple rope unit including a plurality of ropes, a first rope of the plurality of ropes including a pre-failure indicator strand having a tensile strength less than a tensile strength of the multiple rope unit such that the pre-failure indicator strand fails when the multiple rope unit is subject to tension that exceeds the tensile strength of the pre-failure indicator strand before the multiple rope unit fails, the pre-failure indicator strand comprised of a conductive wire;   an indicator that generates a detectable signal associated with the pre-failure indicator strand; and   a transceiver that detects the detectable signal and transmits a warning upon receipt of the detectable signal.   
     
     
         13 . The pre-failure indicator system of  claim 12 , wherein the plurality of ropes also includes a second rope and a third rope. 
     
     
         14 . The pre-failure indicator system of  claim 12 , wherein each of the plurality of ropes is constructed of a material selected from the group consisting of synthetic fibers, natural fibers and a combination of synthetic and natural fibers, each of the plurality of ropes including a plurality of structural strands. 
     
     
         15 . The pre-failure indicator system of  claim 12 , wherein the conductive wire is constructed of a metallic material. 
     
     
         16 . A pre-failure indicator system for determining a degradation or failure condition, the pre-failure indicator system comprising:
 a rope including a plurality of structural strands and a pre-failure indicator strand, the pre-failure indicator strand having a tensile strength less than a tensile strength of the structural strands such that the pre-failure indicator strand fails when the rope is subject to tension that exceeds the tensile strength of the pre-failure indicator strand, the pre-failure indicator strand comprised of a conductive wire having a first end and a second end;   a first signal source connected to the first end and configured to impart a signal into the conductive wire;   a signal detector connected to the conductive wire and configured to detect the signal and convert the signal; and   a signal transmitter in communication with the signal detector, the signal transmitter configured to transmit the converted signal.   
     
     
         17 . The pre-failure indicator system of  claim 16 , wherein the structural strands are constructed from a material selected from the group consisting of natural fibers, synthetic fibers and a combination of natural and synthetic fibers. 
     
     
         18 . The pre-failure indicator system of  claim 16 , wherein the conductive wire is constructed of a metallic material. 
     
     
         19 . The pre-failure indicator system of  claim 16 , wherein the signal is comprised of an electric current. 
     
     
         20 . The pre-failure indicator system of  claim 16 , wherein the signal source is selected from the group consisting of signal generator, an analog signal generator, a function generator, a microwave signal generator, a pitch generator, an arbitrary waveform generator and a frequency generator.