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.

Description

[0001] This application is a continuation of U.S. patent application Ser. No. 10 / 354,378, filed Jan. 30, 2003. This application also claims priority to U.S. Provisional Patent Application Ser. No. 60 / 353,020, filed Jan. 30, 2002, the disclosure of which is incorporated herein in its entirety.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention: [0003] The present invention generally concerns ropes for elevators. In particular, the invention concerns a rope formed from high modulus synthetic fibers for use in elevator systems that employ traction sheaves to drive the rope and the elevator car connected to the rope. The ropes of the invention have an improved structure that reduces compression and abrasion deterioration over the life of the rope. [0004] 2. Description of Related Art: [0005] Conventional traction drive elevators employ an elevator car that is suspended by a rope in a hoistway. The rope typically extends upwardly to the top of the elevator shaft over a drive she...

AI Technical Summary

Benefits of technology

[0011] The yarns comprise a plurality of synthetic filaments that are constructed of high modulus synthetic filaments, such as filaments comprising an aramid polymer sold under the trademark KEVLAR® and more preferably from KEVLAR® 29 or KEVLAR® 49 (KEVLAR® is a trademark of E. I. du Pont de Nemours and Company). A plurality of the pre-twisted substrands are then combined to form each strand. One or more of the strands or substrands may be impregnated or coated with a lubricant to reduce the abrasion among the strands and increase the service life of the rope. The exterior of the rope may then be covered by an outer jacket that provides for traction with the drive sheave.

[0013] The density of the claimed rope is significantly lower than that of steel, enabling smaller drive motors to be placed within the elevator shaft instead of in a separate machine room. Furthermore, a drive sheave to move a half-inch diameter rope according to the invention can be significantly smaller, for example, 10.5 inches in diameter, as compared to sheaves used for half-inch steel ropes which are a minimum of 20 inches in diameter. The smaller sheaves help to reduce the overall space needed to operate the elevator and to reduce the required torque of the motor.

Problems solved by technology

Steel ropes are relatively inexpensive and durable, but they are heavy.

The combined weight of the car and rope often surpasses the tensile strength of the rope and consequently requires the use of additional ropes.

The synthetic ropes developed thus far, however, have not adequately addressed the problems that arise from the use of synthetic materials.

These attempts have not adequately solved the compression and abrasion problems that shorten the service life of the ropes.

In addition, the use of intersheaths requires additional steps in the manufacturing process for such ropes and undesirably increases the elasticity of the rope, which can cause the elevator car to bounce as passengers enter and exit the car.

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