The Benefits of an Elevator Traction Sheave

The Benefits of an Elevator Traction Sheave

If you’re looking for an elevator traction sheave, you’ve come to the right place. These types of pulleys offer a number of benefits, including improved frictional traction, reduced rope wear, and the ability to divert the ropes. Keep reading to learn more about the various types of traction sheaves and how they can help your elevator. Ultimately, you’ll be glad you found this article!

Improved frictional traction

The improved frictional traction of elevator tracers is made possible by improving the sheave’s diameter. This resulted in reduced rope length for each sheave revolution. The reduction of material caused a wild swing in rope tension, which could be directly related to the diameter of the groove. The amount of material lost is another question. The diameter of the sheave is influenced by the E-A-l parameters, which stand for the rope’s elongation module, A-sectional area and l, the actual rope’s length.

When comparing the strand constructions of different types of wires, it was found that the difference between them was the greatest. While both the wire and the rope thickness are approximately the same, the traction sheave’s strands were designed to make contact with the metallic groove. The strands are not free-rotating, which results in secondary flexural stress. Thus, these constructions are not appropriate for elevator ropes or dumb waiters.

An additional sheave is installed in the elevator pit below. The bar is mounted between the counterweight railway lines and guides the cables. This system may be suitable for other kinds of suspension arrangements. Fig. 3 shows a typical elevator traction sheave. A cable or chain is installed between the counterweight railway lines to compensate for these changes. An elevator that can withstand these changes will experience enhanced traction.

An improved elevator traction sheave should have a strong grip on the steel wire rope. A design that minimizes rope wear is preferred. The traction sheave should also be durable and should eliminate the disadvantages of prior art solutions. Therefore, the specific object of the invention is to disclose a new type of engagement between the traction sheave and rope. This new type of engagement is advantageous to elevators and other vehicles.

Durable

Using a durable elevator traction sheave will reduce wear and tear on ropes. The thickness of the rope is approximately eight to ten millimeters, and the traction sheave’s coating will reduce the need for thick surface wires. An elevator rope’s helical wires bear friction, contact pressure, and tension. The stress distribution of the central wire shows a similar trend. Torque loading increases the stress at the left end and decreases the stress at the right end.

A durable elevator traction sheave has excellent grip on steel wire rope and reduces wear on rope. This design overcomes some of the disadvantages of prior-art solutions and discloses a new type of engagement. It also has higher wear resistance than its predecessors, allowing it to withstand high traction loads. The invention is useful for elevators that are used in buildings of different sizes. It can be applied to diverting elevator pulleys.

One example of an elevator with a 2:1 suspension ratio is shown in FIG. 1. The invention is also applicable to elevators with a 1:1 suspension ratio. Furthermore, the invention can be implemented in elevators without diverting pulleys or with another suspension arrangement. It can be adapted for both 1:1 and 2:1 suspension ratios. Once the suspension arrangement is finalized, the invention can be implemented. The invention also addresses the problem of a deficient traction system.

A traction sheave of an elevator is designed for hoisting ropes of substantially round cross sections. It contains grooves for the ropes. The coating is typically less than 100 shore A, and harder near the bottom and edge. A good traction sheave is designed to last decades and withstand high levels of wear and tear. If it fails to function properly, this can lead to an inefficient and unsafe operation of the elevator.

Reduces rope wear

In order to maintain a high level of performance, elevators must be able to relevel themselves whenever passenger load changes. To accomplish this, elevators need to have the ability to compensate for rope stretch without causing a significant amount of noise and vibration. In addition, elevators need to be able to move almost imperceptibly without affecting passenger comfort. Luckily, one new technology is making this process easier.

Various materials are used to produce wire ropes. There are natural and synthetic fibres, as well as steel wire. Whether the fibres are made of steel, they act as lubricant storage. Consequently, fibre cores absorb large quantities of grease, which results in fast rope diameter shrinkage. This is particularly problematic because the grease squeezes out of the fibre core, leading to a loss of volume.

The single-wrap arrangement is another common way to rope elevator machines. It applies to both gearless and geared machines. The ropes have varying amounts of pressure and grooves to provide traction. A good single-wrap arrangement offers 180 degrees of rope contact with the traction sheave without deflecting it. For the longest life, the rope must be replaced every ten years, or as soon as possible.

In addition to conventional ropes, some of the newer systems use diverting pulleys that are located at different heights. This method minimizes rope wear on an elevator traction sheave by making ropes run over two separate portions. This arrangement allows a narrower rope distance for the same size ropes. Using this technique, elevator car ropes can be installed much faster than before.

Diverting pulleys

A traction sheave elevator consists of three parts: the car, the counterweight, and the drive machine unit. These components move in tandem, causing the car to rise and lower, and providing traction as the elevator turns. The elevator car is made of steel and is attached to a counterweight to make the elevator car go up and down. The counterweight are attached to the hoisting ropes, which are three to seven in number and about half an inch in diameter.

The design of the diverting pulleys dictates the final position of the suspension means within the shaft, as well as their diameter and running paths. This is an important consideration for modernization and maintenance, since changing the running path can interfere with the tension between the suspension means and apply different forces to other parts of the traction sheave. Therefore, the diverting pulleys are essential for the proper operation of elevator traction sheaves.

In addition to proper rope lubrication, the elevator traction sheave should also have the same length of ropes and equal tension across them. If the length is longer than 100 metres, the ropes should be untwisted as little as possible. When changing the ropes, make sure to check the grooves of the drive sheave to ensure that the ropes are lined up properly. For better alignment, you can draw a line on the rope to check if the rope is positioned correctly.

The traction sheave tolerances for elevators are much tighter than those of other wire ropes. The DIN EN 12385-5 specifies limiting measures depending on the rope’s nominal diameter and core. PFEIFER DRAKO uses these limiting measures more strictly than DIN EN 12385-5 for full steel rope and implements them in non-tensioned states.

Angle of contact between ropes and traction sheave

In some cases, a suspension rope arrangement is preferable to an air spring. The most efficient rope suspension arrangement can be found in the Finnish patent 56813. In this arrangement, a diverter pulley guides the ropes to the traction sheave. A high-speed DW elevator can have an angle of contact of 235 degrees, with the ropes spanning across the sheave twice.

The resulting angle is the result of a finite-element model that investigates the behavior of the traction rope at the interface. This analysis also discusses the stress and tension distribution in a six-wire rope. It also shows that the traction force increases with the increasing angle. In the case of double-wrap solutions, the contact angle is increased by two-thirds and the number of rope grooves is doubled.

A variation of the invention is shown in figure 2c. The contact angle in this variation is more than 180 degrees and is actually divided into two sections. Each rope is in a groove in the traction sheave. Its continuous contact angle ranges from 200 to 270 degrees. The traction sheave is located within the plane of rotation of the diverting pulleys.

The angle of contact between ropes and elevator traction shaft is the critical parameter for a smooth, safe, and efficient ride. A diverting pulley has equal axial and skew traction forces, and its distance between adjacent rope grooves is much greater than the diameter of the rope. Moreover, a diverting pulley can also be tilted. If this happens, the angle of contact between ropes and elevator traction sheave will be increased and the rope will not be deflected.

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