Elevator Wire Rope Types and Applications
A good elevator wire rope will meet the following requirements:
Requirements for good elevator wire rope
The preconditions for a good elevator wire rope are several. The wire rope must be of adequate strength to protect the traction sheaves from wear. A good elevator wire rope should have a hardness range that is within the nominal strength of the wire. If the wire is too soft, it may cause imprints in the sheave grooves. The wire should be of a proper diameter and length to fit the elevator.
Elevator wire ropes usually have a fiber core. These can be natural or synthetic fibers. Fiber cores are more flexible and provide excellent resistance to contact pressure and long-term support for the elevator wire rope. On the other hand, an independent wire rope core increases the metallic cross-section and reduces tensile stress in individual wires. This type of wire rope is more suitable for low-duty passenger elevators and slow-traveling freight elevators.
The material should be durable enough to support the required weight. A high-quality wire rope will resist abrasion and corrosion. Its tensile strength is sufficient to meet the requirements of the elevator. A rope with low abrasion resistance is also suitable for traction-drive elevators. A rope with high tensile strength is also recommended in deflection sheaves. Stainless steel ropes are more expensive than carbon steel ropes.
A good elevator wire rope must be strong enough to support the loads. This can be achieved by ensuring a sufficient wire diameter. It should be free of dirt and dust. In elevators, the lubricant is often mixed with dust and dirt. If it is not cleaned properly, it will affect the traction. This means that it is impossible to accurately measure the diameter and count wire breaks if there is too much dirt on the rope.
Types of ropes
There are various types of elevator wire ropes on the market today. Some elevators may use simple steel rope, while some may use special wire ropes with reverse bends or wire fatigue. In any case, elevator wire rope is a reliable option with a long lifespan and minimal maintenance. The main benefit of using ropes is their ease of identification and ease of replacement when they become obsolete. Let us discuss the most common types of elevator wire rope and their applications.
The four most common strand constructions used in elevator ropes are: Seale, Warrington, and Filler. Each of these strands has specific advantages and disadvantages. This document will help you determine which rope is most suitable for your particular elevator. The Seale strand construction is more commonly used than the Warrington-Seale strand, while the Warrington-Seale rigged construction is less common.
The asymmetric wedge socket is another type of connector used to connect two ends of rope. This termination has a relatively large diameter, but can be compensated for by using long eye bolts staggered to the rope’s diameter. During installation, a wedge socket is required to secure the dead end of the rope. If both ends of the rope are terminated together, a wedge socket is used instead. But be careful: if the two ends of the rope aren’t secured, they may fall out.
As the vertical rise of buildings increases, the mechanical requirements for the ropes in an elevator are becoming more stringent. To maintain high-rise elevator safety, it is important to choose the right rope for each type of elevator. While simple rope constructions may be fine for elevators with a low payload, the more complex rope constructions are unlikely to be used. In addition to the safety requirements, traction capability is crucial in elevators.
When it comes to selecting the right material for an elevator rope, the choice of fiber core varies widely. Typically, a fiber core is made of polypropylene, but it is possible to use a natural fiber core as well. A few common fiber core types are: 6x25F-FC, which has six strands, used mostly as compensating ropes, and 8x19S-FC, which has eight strands and uses a fiber core.
In the case of a 2:1-suspension elevator, individual deflection sheaves can rotate as much as 90 degrees, causing the elevator rope to vibrate and impact with other ropes. While this doesn’t necessarily affect service life, it may cause a perceptible noise to passengers. The impact may also result from ropes not making central contact with deflection sheaves. In addition, if the ropes are not in central contact, they may be offset from each other and thus rotate, which can also reduce the service life.
The most common type of elevator rope is 8-strand with fibre core. For medium to long-shaft heights, this type of rope is used. For short-shaft applications, an 8-strand rope made from steel has a higher breaking load than natural fibres. The quality of the fibre core determines how durable the rope will be. If you are concerned about ride comfort, you should choose a steel core rope.
The next step is determining which lubricant to use. Some types of lubricants are non-combustible and incompatible with the rope. They contain bitumen and are generally too viscous to be effective. Bitumen lubricants are unsuitable for this application, but they can be effective in reducing friction between the rope and groove. The same rule applies to relubricants.
In an elevator, the diameter of wire rope must be measured within one layer and offset by 90deg. Measure the diameter over two opposite strands when there are even numbers of outer strands. If there are uneven numbers of strands, measure the diameter over one strand in the opposite gap. Then, form a mean value from the two measurements to determine the size of the rope. The final diameter must be equal to the outer diameter minus the inner diameter.
The design of the elevator wire ropes requires analysis based on the properties of the wire. Two wire-rope configurations are considered: one with a GCS and one with a steel galvanized finish. The analysis uses ANSYS software to model the structure. The maximum load to be carried by the wire rope is 45 kN. The wire ropes are then tested for tensile strength and life, and the resulting models are used to design a new elevator.
The hardness of wire increases linearly with nominal wire strength. Elevator ropes have lower wire strengths compared to crane ropes. However, their nominal wire strengths must protect the traction sheaves from wear. In addition, elevator manufacturers in the Far East sometimes request HV hardness for the wires in elevator ropes. In order to ensure the highest strength, elevator ropes should have at least eight strands and a helix shaped wire.
As a result, the high performance ropes can be eliminated from slow-moving elevators. On the other hand, simple rope constructions are not suitable for high-rise installations. The constructions of elevator wire ropes shown in Fig. 13 are all special ropes. These ropes transmit differential force through friction between the rope and sheave. This is known as traction capability. Once the friction between the sheave and rope is sufficient, the elevator will operate smoothly and safely.
The life of a wire rope used in elevators decreases with increasing axial load and sheave bend radii. The outer and inner cross sections of the rope are constantly being bent and thus the traction between the wire and the sheave is also increased. This leads to a significant shortening of the innermost wire, which is considered as one of the main causes of damage. Researchers have studied the traction between the sheave and the wire rope, and the effect of bending and wear on the wire.
Conventional wire ropes are impregnated with lubricant. However, the lubricant causes problems like splashing of oil and adhering to the clothing of maintenance workers. The present invention provides an efficient solution for a number of these problems. This rope also suppresses the suspension load caused by its own weight. Therefore, it provides superior fire protection. Further, this wire rope has a longer lifespan because it can withstand temperatures up to 1,000 degrees C.
In addition to this, the present invention provides an improved mechanism for reducing the size and weight of an elevator. This reduces the required space in the elevator by minimizing the sheave diameter. The sheave 56, in turn, is mounted on a detachable shaft, reducing the height of the motor. In addition to improving the life of the wire rope, the invention reduces the size and weight of the elevator by reducing the friction characteristic between the rope and the sheave.
Another way to improve the life of an elevator wire rope is to increase its radius of curvature. This increases the rope’s elasticity and reduces the contact pressure. However, this method is costly, and should be avoided if possible. Aside from that, a rope that is made of synthetic fibers will last longer than one that does not. So, if you’re considering a replacement of your wire rope, take a look at the following.