Friction Hoist Research Articles

Adaptive boundary control for a friction hoisting system during the loading process

This paper aims at the rope dynamic tension fluctuation (DTF) control in the friction hoisting system (FHS) during the loading process. The exact dynamic modelling of the tail and head ropes connected to the cage is considered. A disturbance observer is proposed to track the actual impact disturbance. The actuator acts at the friction wheel to pretension the system. The use of an adaptive neural network allows for the handling of system uncertainty. An appropriate control law is developed to stabilize the cage and suppress the rope DTF in FHS during the loading process. Numerical simulations and theoretical analysis are presented to prove the feasibility and effectiveness of the proposed control law. Numerical analysis results show that the head rope dynamic displacement fluctuation (DDF) and DTF amplitudes can be suppressed to at least 1/125 of their initial fluctuation amplitudes under the proposed control law.

Research on the Design of Multi-Rope Friction Hoisting System of Vertical Shaft Gravity Energy Storage System

Renewable energy generation methods such as wind power and photovoltaic power have problems of randomness, intermittency, and volatility. Gravity energy storage technology can realize the stable and controllable conversion of gravity potential energy and electric energy by lifting and lowering heavy loads. The hoisting system is an important component of a gravity energy storage system, and its lifting capacity and speed seriously restrict its energy storage capacity, energy conversion efficiency, and operational safety and reliability. In this paper, a design method for a multi-rope friction hoisting system of a vertical shaft gravity energy storage system is proposed. The parameter design and calculation of the hoisting rope, balance rope, and friction wheel of the friction hoisting system under typical conditions were carried out. The static and dynamic anti-slip capabilities of the friction hoisting system under the typical condition were explored. The results show that the maximum acceleration and deceleration speed of the compacted strand wire rope scheme is the largest, and the lifting and lowering time is the shortest. The maximum acceleration and deceleration speed of the triangular strand wire rope scheme is the lowest, and the lifting and lowering time is the longest. The dynamic tension of the hoisting rope at the heavy-load end is positively correlated with the acceleration, and the maximum value occurs in the accelerated lifting stage and decelerated lowering stage of the heavy load. The static anti-slip safety factor between the hoisting rope and the friction lining and the specific pressure between the hoisting rope and the friction lining comply with the requirements of China’s Safety Regulations for Coal Mines. The dynamic anti-slip safety factor of the hoisting system under different rope selection schemes is greater than the minimum value of 1.25 stipulated in the Safety Regulations for Metal and Nonmetal Mines. The research results are of great significance for the safety, reliability, and stable and efficient energy storage of a gravity energy storage system.

Research on full balance friction hoist shiplifts

Research on full balance friction hoist shiplifts

Nonlinear dynamics of time-varying curvature balance rope coupled with time-varying length hoisting rope in friction hoisting system

Mine friction hoisting system is a typical multi-body system composed of traction sheave, conveyance, hoisting rope, and balance rope. Hoisting rope is of large-scale and flexible tension, leading to large amplitude elastic vibration and huge tension fluctuation during hoisting movement. Balance rope is of small tension amplitude and bending modulus, undergoing significant curvature changes, large displacement, and large deformation. Considering the complex coupling vibrations between the moving hoisting rope and balance rope in the ultra-kilometer-deep shaft, a coupling modeling method of the variable-length hoisting rope with the variable-curvature balance rope is proposed. Based on the absolute nodal coordinate formulation(ANCF), the balance rope is modeled by non-equal-length and variable-number elements, and the hoisting ropes on both sides are modeled by variable-length and variable-number elements. A flexible rope vibration experiment platform is built in the laboratory to verify correctness of the proposed theoretical model.The experimental results are in good agreement with those in theoretical simulation. Besides, the nonlinear coupling dynamic behaviors of hoisting rope and balance rope in an ultra-kilometer-deep well are studied. It reveals the non-stationary phenomenon of hoisting rope and balance rope with a long-time range. Both sides of flat balance rope undergo large bending deformation and non-stationary response when transient resonance occurs in hoisting ropes.

Control of friction hoist head rope tensions revisited

ABSTRACT Matching of head ropes and drum grooves in multi-rope friction winding systems is essential for effective load sharing between the winding ropes. Analytical methods were developed in the 1960s to evaluate rope load disparity when rope groove depths are mismatched. Although this historical analysis ignored flexibility in rope groove lining materials, it is widely accepted that rope groove flexibility has the effect of reducing the disparity in load sharing. This paper recounts the original 1960s work in which rope load disparity was analyzed to provide rope groove depth tolerances of rigid grooves and provides a new rope groove depth tolerance for flexible grooves. Both rigid and flexible groove analyses show the importance of an adequate distance between the conveyance at its uppermost normal position in the shaft and the head ropes’ tangent point on the hoist drum. They also show that ground-mounted hoists are more tolerant to groove depth mismatch. Maintenance methods, including the collar-to-collar test, are revisited to reflect this latest analysis.

Hoisting-Rope Continuous Retracting and Releasing Device With Constant Locking Force and Small Impact

Background: With the continuous exploitation of shallow mineral resources, the shallow resources are increasingly exhausted. Therefore, the application of multi-rope friction machine in ultradeep, high speed, heavy load mine will be more widely used. The diameter and dead weight of the hoisting-rope in this heavy-duty deep well are larger, and the internal torsion and bending load are more complex, which makes the replacement of the hoisting rope more difficult. According to the "coal mine safety regulations", the working life of the hoisting-rope is not more than two years, and the hoistingrope of friction hoist is not more than eight months in a harsh environment. Although the existing hoisting- rope replacing methods are mature, there are some problems, such as high labor intensity, long replacement time and low safety, which affect the mine production and are not suitable for deep mine hoisting-rope replacement operation. Objective: The purpose of this patent is to provide a new mechanism for safely and efficiently replacing the hoisting-ropes of multi-rope friction hoists. In addition, the dynamic simulation analysis of the key parameters of the mechanism is carried out, and reasonable design suggestions are given. Methods: A new device is designed to achieve continuous retracting and releasing ropes with constant locking force and small impact, which is mainly composed of sprocket, chain, friction block, mechanism of clamping hoisting-rope and so on. Results: The designed new mechanism can efficiently and safely replace the hoisting-rope of various hoisting equipment and realize the continuous hoisting-rope replacement, limiting the load impact to a great extent. The mechanism is responsible for clamping and releasing the new hoisting-rope and retracting the old hoisting-rope during the whole hoisting-rope replacement process. In the condition of some hoisting-rope with large dead weight, it can also provide enough clamping force, and there will be no phenomenon of hoisting-rope sliding. Conslusion: The device not only realizes the synchronous replacement of the old and new hoistingrope, but also greatly improves the replacement efficiency and safety of the hoisting-rope. The patent effectively solves the existing problems in the process of hoisting-rope replacement and greatly improves work efficiency.

Study on fault diagnosis method for the tail rope of a hoisting system based on machine vision

Healthy operation of the tail rope is crucial to the stable and safe operation of a friction hoisting system. Failure of the tail rope will threaten the property and personnel. In this study, a fault diagnosis algorithm based on deep learning is proposed for the tail rope. Specifically, we add a spatial attention mechanism in the feature extraction stage to assign different weights to different regions in images. This way “guides” the model to focus on more important regions. A class-balance cross-entropy loss is introduced to alleviate the imbalanced data distribution in the actual conditions for enhancing the robustness of the algorithm and its transferability in practical applications. Experimental studies are conducted to validate the algorithm. The accuracy of the algorithm on the conducted dataset is 99.4819%. The accuracy of the provided algorithm is increased by 10% and 7% compared with those of the hand-crafted features, namely, scale-invariant feature transform with support vector machine and random forest, respectively. Results show that the proposed algorithm can meet the requirements of high accuracy and generalization in practical engineering applications.

Effect of Dynamic Load on Adhesive Friction at the Interface Between Friction Lining and Wire Rope of Hoist

Abstract The acceleration, deceleration, and inertia of the friction hoist during lifting and lowering will cause the vibration of the wire rope. This vibration will cause the lifting load to become dynamic, which adversely affects the stability of the friction interface. In this paper, the relationship between the dynamic alternating load and the frictional vibration was established. The fully sliding critical value of dynamic alternating load was revealed. At the fully sliding critical value, the friction force and friction coefficient were the smallest, the adhesive friction was the smallest, and the vibration amplitude increased sharply. This is the most dangerous situation for friction systems. The fully sliding critical value is of great significance to the anti-skidding design of the hoist.

Experimental Study on the Nonlinear Dynamic Characteristics of Wire Rope under Periodic Excitation in a Friction Hoist

The nonlinear dynamic responses of a wire rope under periodic excitation in a friction hoisting system are investigated. Longitudinal excitation experiments of different periodic excitation frequencies are performed. The nonlinear dynamic characteristics of the rope, including transverse, longitudinal, and coupled vibrations, are discussed with time-frequency analysis. The results show that the transverse vibration is a forced vibration following the excitation, while the longitudinal vibration shows a complex, random vibration state. The vibration amplitude and intensity deviate significantly from their linear trend (superharmonic resonance) at some excitation frequencies, and this deviation indicates the typical nonlinear multiorder natural frequency characteristics. The lifting motion can lead to additional corrugated high-order harmonics and cause a fundamental wave distortion of low-frequency excitation. Experimental evidence for the coupling characteristics of the transverse-longitudinal rope vibration in the lifting process is found.

A New Transmission Theory of “Global Dynamic Wrap Angle” for Friction Hoist Combining Suspended and Wrapped Wire Rope

A new transmission theory of “global dynamic wrap angle” for friction hoist is proposed. The theory is based on a mine hoist simulation model which combines the suspended rope with the wrapped rope. Rope dynamics in a suspended section are verified by the field experiment results. The theory holds that the mechanical state of wire rope is dynamic through the whole wrap angle, including deformation, contact and friction. When the rope enters the wrap angle, it provides positive friction and changes direction at a certain boundary point. The demarcation of the boundary depends on the rope load on both sides of the friction pulley. The theory is suitable for accurately analyzing the kinetics of high-speed and heavy-load friction hoisting.

A Bevel Gear Tension Balancing Device for Mining Hoist

Background:: With the increasing mining depth, single rope winding hoist and multi-rope friction hoist may not be feasible in ultra-deep wells. For the single rope winding hoist, larger rope diameter and drum diameter are required, while a lot of inconveniences would arise in the manufacturing process. For the multi-rope friction hoist, the balance tail rope is necessary so that a fluctuation in stress greater than 11.5% of the wire rope breaking force increases. Objective:: The purpose of this patent is to provide an overview of a tension balancing device using new bevel gear system in the multi-rope winding hoist. In the research, varying tension of the rope winded on each drum is conveniently and quickly adjusted in different working conditions. Methods:: A bevel gear balancing device is designed in the multi-rope winding hoist. It mainly consists of big and small output bevel gear, shell, balance bevel gear, and support frame. Results:: Unbalanced tension caused by different lengths of the ropes is compensated without any restrictions. The tension of all wire ropes is always in balance ensured by the balancing mechanism throughout the whole process of lifting and lowering containers. When the winding diameter of the drums is different, the tension of the hoisting-ropes will not be precisely adjusted. But it can be negligible. Conclusion:: The bevel gear balancing device in the patent is installed on the main shaft of the multirope winding hoist. Through analysis, the device was observed to be simple and easy to operate. The tension of the hoisting-ropes can be accurately balanced.

Design and Simulation of Wire Rope Recycling Device in Coal Mine

Aiming at the problem of low efficiency of artificial recycling rope in friction hoist, and the rope recycling device used in underground was proposed and designed. Then the working process of the device was analyzed. With the dynamics analysis softeware, the dynamic characteristics of the recycling device under the maximum load bearing 6.5t conditions was simulated. Finally, the impact force on the device, the contact force between the wire rope and the rope wheel and the force of the wire rope and the rope arranging device were obtained. The simulation results show that the continuous recycling device can run under the rated load, the impact force can reach to 7244N at the start of jog running, and the recycling process is relatively stable, which can meet the requirement of rope arranging. It is possible to recycle the entire replacement wire rope layer by layer without cutting the wire rope, which also can achieve the function of replacing artificially wire rope.

Design and Development of Experimental Platform for Anti-Skid Device of Friction Hoist

There is no effective special equipment to avoid or stop friction hoist sliding accidents. Study on friction property of braking mechanism for anti-skid device of friction hoist is required. Principle of designing and course of developing were given in this paper, including the principle of anti-skid device friction test, the whole structure of the platform design, mechanical transmission and wire rope brake mechanism procession, hydraulic loading system develop, control system development, experiment data acquisition system development and sensors installation. This experimental platform can be used to study the braking performance of braking mechanism for anti-skid device.

Traction capability of friction hoist with bobbin counterbalancing device

Traction capability of friction hoist with bobbin counterbalancing device

Modeling and Vibration Characteristics of Ground Mounted Friction Hoist

Modeling and Vibration Characteristics of Ground Mounted Friction Hoist

Vibration modal shapes and strain measurement of the main shaft assembly of a friction hoist

In order to evaluate the reliability of the main shaft unit of a friction hoisting system, strain measurement is a significant method. In this paper, a test rig of a friction hoisting system was built, which could applied periodically changing load on its main shaft unit; The mechanical analysis under the test load was conducted and the boundary limits were obtained; A three dimensional model of the main shaft unit was built in Pro-E and its finite element analysis was performed in ANSYS; With the analytical result, measuring points for strain rosettes were initially selected; Vibration modal shapes of the main shaft unit were analyzed, based on which Modal Assurance Criterion (MAC) was utilized in the Particle Swarm Optimization (PSO) algorithm to make the final decision of the number and positions of the measuring points; A wireless measurement system was developed to acquire strain signals from the optimized measuring positions; The test result verified the efficiency of the methods employed in this paper and revealed how strain of the main shaft unit changes during running process.

Longitudinal dynamic characteristics of steel wire rope in a friction hoisting system and its coupling effect with friction transmission

Abstract The longitudinal rope dynamics in a friction hoisting system and its coupling effect with friction transmission are investigated. The tension and longitudinal vibration characteristics of the rope are obtained through experiments. The dynamics of rope and friction transmission are obtained by a validated simulation model. The results show that the rope tension is divided into the dynamic tension regime and inertial tension regime due to the multi-frequency cross-linking. The longitudinal rope vibration is embodied as random perturbation. The reduction of the friction coefficient will increase the sliding between the rope and lining, and it will be beneficial to narrowing the dynamic tension regime. The increase in the longitudinal rope vibration will reduce the friction force between the rope and lining.

Research on Components Characteristics of Single Container Friction Hoist

To improve the system of a single container multi rope friction, from the point of view of safety conditions, based on Euler formula, combined with dimensionless method, the static tension ratio analysis and research into the system, draws a single container friction hoisting system Components characteristics of static tension ratio C, in order to explore components configuration of the system and anti-skid, provides a simple, convenient, and reliable theoretical basis.

Experimental research on effect of wire rope transverse vibration on friction transmission stability in a friction hoisting system

The transverse vibration of a wire rope and the effect on friction transmission stability in a friction hoisting system are investigated. A simulation model is established by Adams/cable and then it is validated by an experimental device using the time-frequency technology. The influence of different factors (including speed, acceleration, load, rope length) on transverse vibration is discussed. A method is employed to weaken the transverse vibration by adjusting the initial acceleration time. The results show that, the transverse vibration reduces the actual contact area of the wrap angle. The intensification of transverse displacement at the tangent point of the pulley reduces the friction force of the following rope in the wrap angle and increases the instability of the friction force.

Comparison of the thermophysical properties, microstructures, and frictional behavior of lining materials used in mine hoists

Mine hoists for medium depth and deep mines in China rely on friction hoists. Proper function of the equipment involves controlled frictional contact between a rope and a lining. While there has been a lot of empirical testing of friction hoist materials, studies of the effects of their microstructure and basic properties on friction and wear have largely been neglected. Three commercial grade linings with similar compositions were investigated (trade names: K25, G30, and GM-3). Their thermo-physical properties were measured using XPS, FTIR and TGA. Their hardness and other properties were correlated with their microstructures and frictional behavior. The DTG curves of the three linings follow a similar pattern and their weight loss rate peaks occur in the second stage due to the cyclodehydration of phenolic hydroxyl and fracture of methylene. GM-3, which is highest content of inorganic filler, had the smallest weight loss. Reciprocating sliding friction and wear tests indicated that higher contents of methylene and filler improve the friction coefficient. Adhesive wear is observed when the friction material hardness is relatively low. When the sliding velocity increases, the friction coefficient of two of the linings (K25 and GM-3) increases, but that of G30 first rises then falls. The reasons for these differences in behavior are discussed.