Synthetic fiber rope for an elevator
View Patent ↗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:
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 yam is twisted about its longitudinal axis in a first direction, and the plurality of yams are twisted about each other in a second direction to form each pre-twisted substrand, and wherein the yams 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 synthetic filaments comprise aramid filaments.
4. A rope for an elevator according to claim 1 , wherein the first direction and the second direction are opposite.
5. A rope for an elevator according to claim 1 , wherein the first direction and the second direction are the same.
6. A rope for an elevator according to claim 1 , wherein at least one layer further comprises a lubricant in one or more of the strands of the layer.
7. A rope for an elevator according to claim 6 , wherein the lubricant comprises particles of polytetrafluoroethylene.
8. A rope for an elevator according to claim 1 , wherein the yams comprise KEVLAR® aramid filaments.
9. A rope for an elevator according to claim 8 , wherein the KEVLAR® aramid filament comprises KEVLAR® 29 filaments or KEVLAR® 49 filaments.
10. A rope for an elevator according to claim 9 , having a diameter in the range of% inch to 1 inch.
11. A rope for an elevator according to claim 10 , wherein the initial breaking strength of a half inch diameter rope is greater than about 25,000 lbs.
12. A rope for an elevator according to claim 1 , further comprising an exterior jacket comprising nylon or a woven polyester.
13. A rope for an elevator according to claim 12 , wherein the exterior jacket is woven in a Crosshatch pattern.
14. A rope for an elevator according to claim 1 , wherein the yarns are individually twisted at between 1–6 turns per inch in a counterclockwise direction.
15. A rope for an elevator according to claim 14 , wherein the plurality of yams are twisted together to form the substrand at between 1–6 turns per inch in a clockwise direction.