A regular inspection and maintenance of gantry crane is crucial to improve safety and productivity. The following are maintenance tips for the main components of gantry cranes.
Main Components Maintenance
Wire ropes can be regarded as vulnerable parts. Lack of maintenance is one of the main reasons for the short life of wire ropes.
1. Inspection and maintenance of wire rope
- It is necessary to check the fixing condition of the end of the wire rope and the wear of the wire rope regularly.
- If the rope diameter is reduced, the elasticity is reduced, orthe deformation is found, it should be dealt with in time.
- The wire rope should be kept in a good lubrication state. When lubricating, use a wire brush to remove dirt and clean with kerosene, and heat the lubricating oil to above 80°C so that the oil can be immersed in the steel wire rope.
2. Replacement of the wire rope
- The replacement of a new wire rope must comply with the original design model, specification and tensile strength requirements.
- When the wire rope is not long enough, it is forbidden to connectthe ropes to use.
- When there is not enough information to explain the performance of the wire rope, the breaking force test shall be carried out according to the regulations.
3. Scrap of wire rope
- The scrapping of a wire rope can be determined by the number of wire breaks in each lay length.
- When any section of the steel wire rope or the outer steel wire is uniformly worn or corroded to more than 40% of the original diameter, it shall be scrapped.
- When a strand of steel wire in the wire rope breaks, it must be scrapped.
- Check whether the fixing of the bearing seat, the tightness of the bearing cover, the lubrication in the bearing and the tightness of the gasket meet the requirements.
- When there is rolling noise, add lubricating oil first. If it still does not work, it should be overhauled. When disassembling the bearing, it must be heated to 80-100℃ with oil for no less than 15 minutes.
- Check whether the wheel has cracks, and whether the rim and tread are worn.
- It should be ensured that the wheel diameter deviation of the same crane does not exceed 0.0005D (Drefers to the wheel diameter).
Drum And Pulley
- Check the surface of the groove, whether the lubrication system isin a good condition, whether the pulley can rotate freely on the shaft, whether the bearing and the shaft are firmly fixed, etc.
- When the length of the groove edge wear does not exceed 20% of the whole length, it is allowed to repair with electric welding and process after repair. If the depth of the abrasion does not exceed 2mm, just use a file to trim.
- When the reducer is driving, there should be no strong noise and impact sound.
- Check the degree of wear and meshing of the working surface of the gear.
- The gear on the shaft must not move radially or axially.
- If oil leakage is found, it may be the connecting bolts of the upper and lower housings of the reducer, the oil drain plug and the oil cover bolts are not tightened, or the sealant has failed.
- Check whether all couplings are installed firmly, whether the bolts are tightened, and whether they are jumping during work.
- The brake of the hoisting mechanism should be inspected during the shift, and the brake of the running mechanism shall be inspected every 2-3 days.
- During the inspection, attention should be paid to that the various parts of the brake system act flexibly. When braking, the brake shoes should be correctly attached to the brake wheel.When opening, the gaps on both sides of the brake wheel should be equal.
- Check the braking torque. The lifting mechanism must reliably support 1.25 times the rated lifting capacity. For the running mechanism, within the specified braking distance, it should ensure that the crane or trolley can be braked.
- When the brake pad is worn more than 1/2 of the original thickness, it should be replaced. When the brake wheel surface has a concave depth greater than 0.5mm or scratches, it should be polished again. The surface of the brake wheel should be cleaned with kerosene on a regular basis.
- When a peculiar smell or smoke is found during braking, the gap on both sides of the brake wheel should be adjusted in time to make it equal. The rotating part of the brake shaft bolt should be lubricated once a week to keep it in good condition.
- When using the control screen, pay special attention to the maintenance of the positive and negative contactors, and keep the contacts smooth and normal pressure.
Common Problems With Gantry Cranes
To make your gantry crane have a long service life, we provide you with some common troubles of the gantry crane when you use it and some solutions to sole them. Hoist mechanism is the same except and gantry crane, there are many differences, such as rotation mechanism, luffing mechanism, there are also unique in their metal structure so that the fault situation also has the special place, here is the gate seat lifting machine common fault. The followings are failure phenomenon, cause analysis and troubleshooting method of rotating mechanism.
1. Wrench the handle of the main controller of the rotating mechanism, and the mechanism is not operated
- Cause analysis: the contact of zero contact is bad or damaged.The voltage relay coil is broken or the lead is disconnected.The over-current relay often closes the contact.The wiring bolts are loose, the contact is bad and the bolts are tightened.
- Troubleshooting: repair or replace the relevant components of the gantry crane.
2. The speed of rotation is slow and the speed is not up to the rated speed
- Cause analysis: control panel in a stage of accelerating contactor is not good, will cause the pull and not after the next level of the contractor, it can not access the corresponding resistance in a motor rotor motor removed, it is not up to the rated speed.
- Elimination method: check each acceleration contactor of each constant open contact, so that the contact is good at work, and the circuit at all levels is unblocked.
3. When the rotating mechanism is operated, the fuselage is jitter and cannot move.
- Cause analysis: the first or second stage resistance of the rotor circuit of a rotary motor has a circuit breaker, causing the motor to run in phase, and the fuselage jitter is not moving.
- Elimination method: find out the resistance of the motor rotor loop and find out the circuit breakers.
4. The rotating mechanism can sometimes be rotated in one direction
- Cause analysis: The interlocking contact of the command controller is not closed in this direction.The total power contactor is damaged by interlocking contact and bad contact.The connection head is loose and should be tightened.
- Troubleshooting: Troubleshooting the fault contacts. The rotary table supporting device of the sleeve roller wheel, the horizontal deformation of the ring down raceway, causes the rotary part running on the raceway.
5. Many small cracks and concave denudations along the circumferential direction on the track surface
- Cause analysis: walking track foundation is not strong and low-lying, laying the adjustment of mismanagement, the two-track in the same section of the height difference of serious ultra poor and single track serious distortion in the long run.The overall crane is tilted, which is indirectly reflected in the circular orbit, causing a small area of stress concentration at the contact of the track and the roller.The hardening layer and the body are easily separated and peeled off under the high load repeated rolling of the roller, forming partial fatigue damage on the track surface.
- Elimination method: commonly used repair method: disassemble the rotating parts and send factories to repair with large machine tools.Temporary repair method: stop the rotating parts to the end, the cracks in the cracks and the peeling off.
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