Only the correct use of regular inspections and frequent attention to maintenance can ensure the normal and safe operation of single-girder cranes . The inspection is mainly to observe and find the worn or damaged parts, and then repair or replace them. At the same time, the welding reliability of all the fastening elements must be checked Crane for sale .
One of the most important maintenance tasks is to pay attention to the lubrication of the various mechanisms of the single-beam crane . Only regular and correct lubrication of the transmission mechanism can prolong the service life of the crane .
The following briefly describes the maintenance and repair of important parts of single-girder cranes:
1. Wire rope
Whether the steel wire rope used for lifting can continue to be used reliably or whether it needs to be replaced. It is determined by the number of wire breaks in each pitch. The definition of drum pitch is the axial distance around each strand of rope.
If the number of steel wire breaks in each pitch of the lifting steel rope on the electric hoist has reached the requirements in Table 1, the steel rope should be immediately scrapped and replaced with a new rope. If the number of steel wire breaks does not meet the requirements of Table 1, in principle, it is allowed to continue to use, but it must be checked closely at any time to ensure safety.
Wire rope scrap specification table 1
| Safety factor of steel rope | Wire rope mechanism | |
| 6×19=114 (a core of organic matter) | 6×37=222 (a core of organic matter) | |
| When the number of wire breaks within a strand of the wire rope reaches the following value, it shall be scrapped | ||
| 4.5 | 12 | twenty two |
In order to improve the wear of the wire rope, the wire rope must be lubricated with wire rope grease every 10 to 15 days. When lubricating, use a cloth soaked in kerosene to try out the dirty grease before applying new grease.
It is absolutely forbidden to use acidic or alkaline lubricated steel wire ropes.
2. Wheel
No cracks are allowed on the wheels, and no cracks are allowed on the wheel hub. Therefore, during use, it must be checked regularly (once a month). When the wheel has cracks or the wheel hub is cracked, a new wheel should be replaced immediately.
After the crane is used for a long period of time, due to uneven wear, the working diameter of each wheel may become unequal. At this time, the wheels should be re-machined.
3. Crane walking mechanism
The oil should be refueled once a month, and the degree of wear of the gears should be checked. The correctness of the meshing, the reliability of the gear assembly on the shaft and the tightness of the case connection. In addition, the degree of tightness between the ring gear and the wheel.
When the reduction box is working, there should be no strong noise and impact sound, and the gear should not swing on the shaft or produce axial movement. If such phenomena are discovered, they should be eliminated immediately.
The gearbox should be cleaned and changed every six months.
Run the motor and adjust the adjusting nut according to Figure 4 to ensure the axial movement of 2~4mm.
4. Rolling bearings
Regularly check the reliability of the rolling bearing in the mechanism, whether the retaining ring is tight, and whether the bearing is damaged.
Rolling bearings should be refueled once every half a month.
When the bearing is in operation, a strong rubbing noise occurs. It means that the bearing lacks lubricating oil or the bearing is damaged should be repaired or replaced in time.
5. Metal structure
The metal structure is the largest and main component of a single-beam crane. It must be inspected and maintained at least once a year to check whether there are cracks in the weld. If any, stop using it immediately, find out the cause and remove all cracks, and Use high-quality welding rods for re-welding.
In order to prevent the rust and corrosion of the metal structure, depending on the previous painting, repaint it every 1 to 3 years, and carefully remove the old paint before painting.
6. Motor
Before the installation of the single beam crane, all motors should be measured with a 500-volt megohmmeter to measure the insulation resistance of their coils. The stator insulation resistance of the motor should not be less than 1 megohm, and the insulation resistance of the rotor coil should not be less than 0.5 megohm.
If the insulation resistance is lower than the above regulations due to operation or long-term storage, the motor must be removed and dried. When measuring the insulation resistance of the rotor, the carbon brush in the brush holder on the slip ring must be removed, and the insulation resistance of the brush holder should also be measured-the standard is the same as that of the rotor.
Before the motor is dried, compressed air should be used to carefully blow away the dust in the machine.
During drying, the temperature outside the motor should be gradually increased. The temperature of the motor should not exceed 50°C during the first 2 to 3 hours of drying, and the temperature of the motor should gradually reach the limit value of 70°C in the next 6 to 7 hours. After reaching the limit temperature, continue to dry for 3 to 5 hours.
To measure the temperature of the motor, only alcohol thermometers are allowed, not mercury thermometers.
In addition, the pressure of the brush holder of the motor should be checked. For the same motor, the pressure of the brush holder spring should be the same.
Good maintenance and repair of single-beam cranes can not only reduce the probability of failure of the crane, but also greatly increase the service life of the crane. why not.
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