Synthetic fiber rope for an elevator

Abstract

A synthetic rope for an elevator having improved resistance to compression and abrasion is provided and comprises a plurality of strands forming layers of the rope, each strand formed from a plurality of pre-twisted strands made from high modulus synthetic filaments. One or more of the strands or layers of strands may be impregnated with a lubricant, such as polytetrafluoroethylene, to reduce the abrasion among the strands and substrands, and increase the service life of the rope. The exterior of the rope may be covered by a jacket that provides for traction with the drive sheave. An elevator system comprising the claimed rope is also provided.

1 . A rope for an elevator comprising: 
 a plurality of strands forming the rope, each strand comprising a plurality of pre-twisted substrands, each substrand comprising a plurality of yarns twisted together, wherein each yarn is twisted about its longitudinal axis in a first direction, and the plurality of yarns are twisted about each other in a second direction to form each pre-twisted substrand, and wherein the yarns comprise high modulus synthetic filaments.    
   
   
       2 . A rope for an elevator according to  claim 1 , wherein the synthetic filaments comprise polyamide filaments, polyolefin filaments, polybenzoxazole filaments, polybenzothiazole filaments, or mixtures thereof.  
   
   
       3 . A rope for an elevator according to  claim 1 , wherein the filaments comprise aramid filaments.  
   
   
       4 . A rope for an elevator according to  claim 1 , wherein the plurality of pre-twisted substrands are helically wrapped around one another to form each strand.  
   
   
       5 . A rope for an elevator according to  claim 4 , wherein the first direction and the second direction are opposite.  
   
   
       6 . A rope for an elevator according to  claim 4 , wherein the first direction and the second direction are the same.  
   
   
       7 . A rope for an elevator according to  claim 4 , wherein the rope further comprises a plurality of layers of strands.  
   
   
       8 . A rope for an elevator according to  claim 7 , wherein the layers comprise an inner layer, middle layer and outer layer.  
   
   
       9 . A rope for an elevator according to  claim 7 , wherein at least one layer comprises a lubricant in one or more of the strands of the layer.  
   
   
       10 . A rope for an elevator according to  claim 9 , wherein the lubricant comprises particles of polytetrafluoroethylene.  
   
   
       11 . A rope for an elevator according to  claim 4 , wherein the yarns are comprised of KEVLAR® aramid filaments.  
   
   
       12 . A rope for an elevator according to  claim 11 , wherein the KEVLAR® aramid filaments comprise KEVLAR® 29 filaments or KEVLAR® 49 filaments.  
   
   
       13 . A rope for an elevator according to  claim 12 , wherein the diameter of the rope is in the range of ¼ inch to 1 inch.  
   
   
       14 . A rope for an elevator according to  claim 13 , wherein the breaking strength of a half inch diameter rope is initially greater than about 25,000 lbs.  
   
   
       15 . A rope for an elevator according to  claim 4 , further comprising an exterior jacket of nylon or a woven polyester.  
   
   
       16 . A rope for an elevator according to  claim 15 , wherein the exterior jacket is braided in a Crosshatch pattern.  
   
   
       17 . A rope for an elevator according to  claim 4 , wherein the yarns are individually twisted at between 1-6 turns per inch in a counterclockwise direction.  
   
   
       18 . A rope for an elevator according to  claim 17 , wherein the plurality of yarns are twisted together to form the substrand at between 1-6 turns per inch in clockwise direction.  
   
   
       19 . A rope for an elevator comprising: 
 an inner layer of three strands laid helically around one another;    a middle layer of six strands laid helically around the inner layer; and    an outer layer of twelve strands laid helically around the middle layer;    wherein each strand comprises a plurality of pre-twisted substrands, each substrand comprising a plurality of yarns twisted together, wherein each yarn is twisted about its longitudinal axis in a first direction, and the plurality of yarns are twisted about each other in a second direction to form each pre-twisted substrand, and wherein the yarns comprise high modulus synthetic filaments.    
   
   
       20 . A rope for an elevator according to  claim 19 , wherein the synthetic filaments comprise polyamide filaments, polyolefin filaments, polybenzoxazole filaments, polybenzothiazole filaments, or mixtures thereof.  
   
   
       21 . A rope for an elevator according to  claim 19 , wherein the synthetic filaments comprise aramid filaments.  
   
   
       22 . A rope for an elevator according to  claim 19 , wherein the first direction and the second direction are opposite.  
   
   
       23 . A rope for an elevator according to  claim 19 , wherein the first direction and the second direction are the same.  
   
   
       24 . A rope for an elevator according to  claim 19 , wherein at least one layer further comprises a lubricant in one or more of the strands of the layer.  
   
   
       25 . A rope for an elevator according to  claim 24 , wherein the lubricant comprises particles of polytetrafluoroethylene.  
   
   
       26 . A rope for an elevator according to  claim 19 , wherein the yarns comprise KEVLAR® aramid filaments.  
   
   
       27 . A rope for an elevator according to  claim 26 , wherein the KEVLAR® aramid filament comprises KEVLAR® 29 filaments or KEVLAR® 49 filaments.  
   
   
       28 . A rope for an elevator according to  claim 27 , having a diameter in the range of ¼ inch to 1 inch.  
   
   
       29 . A rope for an elevator according to  claim 28 , wherein the initial breaking strength of a half inch diameter rope is greater than about 25,000 lbs.  
   
   
       30 . A rope for an elevator according to  claim 19 , further comprising an exterior jacket comprising nylon or a woven polyester.  
   
   
       31 . A rope for an elevator according to  claim 30 , wherein the exterior jacket is woven in a Crosshatch pattern.  
   
   
       32 . A rope for an elevator according to  claim 19 , wherein the yarns are individually twisted at between 1-6 turns per inch in a counterclockwise direction.  
   
   
       33 . A rope for an elevator according to  claim 32 , wherein the plurality of yarns are twisted together to form the substrand at between 1-6 turns per inch in a clockwise direction.  
   
   
       34 . A rope for an elevator comprising: 
 an inner layer of strands laid in a helical orientation; and    one or more outer layers of strands, each outer layer of strands laid helically around the preceding layer,    each strand comprising a plurality of pre-twisted substrands, each substrand comprising a plurality of yarns twisted together, wherein each yarn is twisted about its longitudinal axis in a first direction, and the plurality of yarns are twisted about each other in a second direction to form each pre-twisted substrand and wherein the yarns comprise high modulus synthetic filaments.    
   
   
       35 . A rope for an elevator according to  claim 34 , wherein the synthetic filaments comprise polyamide filaments, polyolefin filaments, polybenzoxazole filaments, polybenzothiazole filaments, or mixtures thereof.  
   
   
       36 . A rope for an elevator according to  claim 34 , wherein the filaments comprise aramid filaments.  
   
   
       37 . A rope for an elevator according to  claim 34 , wherein the first and second directions are opposite.  
   
   
       38 . A rope for an elevator according to  claim 34 , wherein the first and second directions are the same.  
   
   
       39 . A rope for an elevator according to  claim 34 , wherein at least one layer further comprises a lubricant in one or more of the strands in the layer.  
   
   
       40 . A rope for an elevator according to  claim 39 , wherein the lubricant comprises particles of polytetrafluoroethylene.  
   
   
       41 . A rope for an elevator according to  claim 34 , further comprising a woven exterior jacket.  
   
   
       42 . A rope for an elevator according to  claim 41 , wherein the exterior jacket is formed of polyester or nylon and is woven in a cross-hatch pattern.  
   
   
       43 . An elevator system comprising: 
 an elevator car;    a rope comprising a plurality of strands, each strand comprising a plurality of pre-twisted substrands, each substrand comprising a plurality of yarns twisted together, wherein each yarn is twisted about its longitudinal axis in a first direction, and the plurality of yarns are twisted about each other in a second direction to form each pre-twisted substrand, and wherein the yarns comprise high modulus synthetic filaments;    a drive motor for displacing the rope in order to move the car;    one or more sheaves for guiding the displacement of the rope; and    a counterweight coupled to the rope for counterbalancing the weight of the car.    
   
   
       44 . An elevator system according to  claim 43 , wherein the synthetic filaments comprise polyamide filaments, polyolefin filaments, polybenzoxazole filaments, polybenzothiazole filaments, or mixtures thereof.  
   
   
       45 . An elevator system according to  claim 43 , wherein the synthetic filaments comprise aramid filaments.  
   
   
       46 . An elevator system according to  claim 43 , wherein the rope is covered with a woven exterior jacket.  
   
   
       47 . An elevator system according to  claim 46 , wherein the jacket is formed from polyester or nylon and is woven in a Crosshatch pattern.  
   
   
       48 . An elevator system according to  claim 43 , further comprising a lubricant in one or more of the strands.  
   
   
       49 . An elevator system according to  claim 48 , wherein the lubricant comprises particles of polytetrafluoroethylene.