Research on the method of adjusting the angle between the steel wire rope and the pulley of a single rope winding hoist
The winding hoist is a commonly used lifting equipment in mines and an important channel connecting the upper and lower shafts of the mine. The steel wire rope plays an important role in the entire lifting system, as the lifting load of a single rope winding hoist is carried by a single steel wire rope. If problems with the steel wire rope are not resolved in a timely manner, it can cause major safety accidents.
The winding hoist in a certain mine has been used to lift rough stones for a long time. During the annual inspection, the main hoisting rope was replaced and a trial run was carried out. In the subsequent daily inspection, it was found that when the cage reached a certain middle section, the corresponding steel wire rope was severely worn and the rope diameter changed rapidly. After two consecutive weeks of measurement, the thinnest rope diameter had reached 27.1 mm (the original rope diameter was 28.0 mm), and the wear amount had reached 1.0 mm. If not managed properly, the increase in wear would inevitably lead to a disaster. After careful observation, it was found that the position where the steel wire rope was worn was exactly at the point where the steel wire rope was replaced, and the angle between the steel wire rope and the outside of the pulley was at its maximum. Article 6.4.4.12 of the "Safety Regulations for Metal and Non Metal Mines" stipulates that in a winding lifting system, the maximum deviation angle of the steel wire rope from the drum to the pulley should not exceed 1 ° 30 '. If this value is exceeded, the steel wire rope will interfere with the pulley rim, resulting in wear and tear of the steel wire rope. The lifting system used in this mine belongs to this situation.
In the face of this situation, it is necessary to adjust the deflection angle of the steel wire rope pulley. There are many methods to adjust it. One method is to replace the pulley pad to reduce the wear of the steel wire rope on the pulley rim. However, with the extension of use time, the pad wear will also intensify, and the steel wire rope will eventually interfere again; Another method is to adjust the horizontal position of the drum, so that the drum can move as a whole, remove the original foundation and rebuild it, but the amount of work is large and time-consuming.
The author proposes a simple and feasible method to rotate the base of the crown wheel at a small angle in the horizontal direction, so that the rope entry point of the crown wheel is aligned with the center of the corresponding drum, and the inner and outer angles of the steel wire rope are almost equal, thereby achieving the effect of angle adjustment.
Measurement of the inner and outer deflection angles of the steel wire rope and crown wheel before adjustment
1.1 Plan for Measuring the Inner and Outer Deviation Angle of the Celestial Wheel
The schematic diagram of the inner and outer deflection angles of the pulley is shown in Figure 1. In order to determine whether the abnormal wear of the wire rope is caused by a large inner and outer deflection angle of the wire rope, it is necessary to measure the inner and outer deflection angles of the hoist. From Figure 1, it can be seen that α 1 is the inner deflection angle of the pulley steel wire rope, and α 2 is the outer deflection angle of the pulley steel wire rope. When the steel wire rope is near the left and right rope blocking plates, the deflection angle between the steel wire rope and the pulley reaches its maximum.
Due to the damage of the centerline and axis of the hoist drum, the axis of the crown wheel cannot be directly measured, and only indirect methods can be used to determine the centerline and axis of the drum, as well as the centerline and axis of the crown wheel.
Set up a total station in a location with good visibility conditions in the computer room, establish a hypothetical coordinate system, take the measurement station coordinates O (100010001000), and measure 1 set of data (3 points per set) in the middle of each pulley rope groove, for a total of 2 sets of measurements; Measure 1 set of data (3 points per set) on each side of the inner wall of the drum rope guard, for a total of 4 sets. The measured data is listed in Table 1. In the table, measuring points 1-3 are the measured coordinates of the first celestial wheel, 4-9 are the corresponding coordinates of the first celestial wheel, 10-12 are the measured coordinates of the second celestial wheel, and 13-18 are the corresponding coordinates of the second celestial wheel.
Table 1 Summary of Measurement Data
1.2 Calculate the inner and outer deflection angles of the steel wire rope
The first step is to perform 3D modeling processing on the measured data in CAD, and obtain the axis of the drum and the center line and axis of the crown wheel by fitting them into a circle and determining the center of the circle.
The second step is to calculate the inner and outer deflection angles of the celestial wheel in CAD software, and the results are as follows:
The inner inclination angle of the first celestial wheel is 0 ° 47 ′ 53 ″; The outer deviation angle of the first celestial wheel is 1 ° 39 ′ 24 ″; The internal inclination angle of the second celestial wheel is 0 ° 12 ′ 40 ″; The external deviation angle of the second celestial wheel is 2 ° 15 ′ 08 ″.
According to Article 6.4.4.12 of the "Safety Regulations for Metal and Non Metal Mines", both the outer deflection angle of the 1st and 2nd pulleys exceed the prescribed 1 ° 30 ′ and need to be adjusted.
2 Adjustment Plan
The principle of adjusting the inner and outer deflection angles of the pulley and steel wire rope must ensure that the values of the inner and outer deflection angles meet the requirements of the "Safety Regulations for Metal and Non Metal Mines", while also ensuring that the position of the rope outlet point does not change, that is, the rope outlet point should be maintained directly above the center position of the cage to ensure the stability of the lifting container, as shown in Figure 2. θ is the angle of overall rotation between the first celestial wheel and the base, rotating clockwise from the rope point as the origin; B1 and B2 are the inner and outer deflection angles before adjustment, and picture 'shows the adjusted inner and outer deflection angles. The adjustment method for the 2nd and 1st celestial wheels is the same, with only the rotation direction being counterclockwise.
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2.1 Locate the rope point
Draw two perpendicular lines along the circumference of the first and second wheels respectively below the wheel, which are the extension lines of the two cage lifting ropes. The two perpendicular lines intersect with the horizontal plane of the base below the wheel, and these two intersection points are the rotation origin of the adjustment of the first and second wheels, namely the rope exit point (rotating around this point).
2.2 Wheel Shift
After determining the rotation reference point, adjust the base of the first pulley based on this point as the center. Rotate the base of the first pulley horizontally clockwise along the rope exit point by a certain angle, so that the rope entry point of the pulley is aligned with the center of the drum, and the inner and outer angles of the pulley steel wire rope are basically equal; Rotate the base of the second celestial wheel counterclockwise by a certain angle, align it with the center position of the corresponding drum, and after all are turned to the designated position, fix the base as shown in Figure 3.
2.3 Check and adjust the inner and outer deflection angles of the steel wire rope
After the adjustment is completed, measure the inner and outer deflection angles of the steel wire rope pulley again according to the above measurement method. The comparison of the inner and outer deflection angles of the steel wire rope before and after adjustment is shown in Figure 4. The measurement results are as follows:
The inner inclination angle of the first celestial wheel is 1 ° 17 ′ 53 ″; The outer deviation angle of the first celestial wheel is 1 ° 19 ′ 24 ″; The internal inclination angle of the second celestial wheel is 1 ° 14 ′ 40 ″; The external deviation angle of the second celestial wheel is 1 ° 18 ′ 08 ″.
The measurement results meet the requirements of the "Safety Regulations for Metal and Non Metal Mines".
2.4 Wear status of steel wire rope after adjustment
After adjusting the Tianlun, perform rope adjustment on the cage of the hoist system, and check whether there is any deviation between the steel wire rope and the original position. After confirming that there are no problems, conduct a test run. After two weeks of observation and monitoring, the diameter of the steel wire rope remained relatively stable, with no abnormal wear and tear. At the same time, there was no interference between the steel wire rope and the outer edge of the pulley.
3 Conclusion
The problem of wire rope deviation angle in mine hoists is one of the important factors affecting the safe operation of wire ropes in the hoisting system. If the wire rope deviation angle is too large, it will increase the wear of the wire rope and the rim of the pulley, reduce the service life of the wire rope, and even cause rope breakage accidents when the wear is severe, resulting in irreparable losses.
When solving the problem of excessive deflection angle of the lifting rope during the operation of the hoist, the existing foundation and installation position of the hoist were not changed. Instead, the pulley was rotated at an appropriate angle along the rope exit point, ultimately meeting the usage requirements stipulated in the "Safety Regulations for Metal and Non Metal Mines". After later observation, the steel wire rope no longer showed abnormal wear, and the fact proves that this method is feasible.