Topic: Maintenance of garbage grab bridge crane
The correct use and maintenance of the garbage grab bridge crane have a great relationship with the safety of production and the service life of the crane. Therefore, the crane must be regularly inspected and tested. The inspection or testing must comply with the “GB6067-85 Safety Regulations for Lifting Machinery” 》And other relevant documents. Daily maintenance and maintenance can be carried out as follows Crane for sale .
The garbage grab bridge crane should be maintained well
1. Maintenance and maintenance of lifting mechanism
1.1 Maintenance and maintenance of hoisting frequency conversion motor
1) The temperature rise of the motor during normal operation should not exceed the allowable temperature. Measured with a thermometer, the temperature rise of the iron core or casing generally does not exceed 60K. The bearing temperature rise generally does not exceed 95°C.
2) Pay attention to the smell, vibration and noise of the motor. If you smell burnt smell, find abnormal vibration or other noise, you should stop it for inspection immediately.
3) Regularly check the bearings and replenish No. 2 lithium grease.
4) Pay attention to keep the motor clean, and do not allow water droplets, oil stains and debris to enter the motor.
5) Due to the influence of the higher harmonics of the inverter, the noise and vibration of the variable frequency motor are greater than that of the grid power supply, especially when the resonance frequency is consistent and resonance occurs. The rigidity of the system can be enhanced or the frequency jump function of the inverter can be used to avoid the resonance frequency and achieve smooth operation.
6) For other contents, please refer to the “Instruction for Use and Maintenance of Variable Frequency Motors”.
1.2 Maintenance and maintenance of lifting reducer
1) Reducer lubricating oil should be N68, N100, N150, N220 medium-load extreme pressure gear oil in GB5903. The high grade should be selected in the south, and the low grade should be selected in the north.
2) The oil should be changed once after 3 months of first use. After continuous use, the oil should be changed once every six months, and the oil can be changed once a year for intermittent use.
3) The oil level of the reducer should be checked frequently. Note: At any time, the oil level cannot be lower than the lower limit of the oil standard.
The inspection should be carried out after the reducer is stopped and sufficiently cooled down.
4) During the use of the reducer, the connecting parts and fasteners must not be loosened.
5) If you find oil leakage on the joint surface during use, please disassemble the leaking parts and apply 601 sealant; if you find oil leakage on the oil seal, please replace it according to the crude oil seal model.
6) For other content, please refer to “Crane Reducer Operation Manual”.
1.3 Maintenance and maintenance of lifting brake
1) The brakes should be inspected every shift, and the inspection contents are as follows:
Whether the thruster has oil leakage or oil leakage. Whether the amount of oil is sufficient, add appropriate oil when insufficient, and replace the oil regularly.
Whether the insulation of the motor lead-in is good.
Each part of the brake system should act accurately and flexibly, and the nuts and safety washers that should be fixed should not be loosened.
The brake spring, brake arm, base, lever, screw, etc. should be replaced in time if there are cracks.
Plastic deformation of the brake spring should be replaced.
The brake shoe should fit correctly on the brake wheel, and its actual contact area should not be less than 50% of the theoretical contact area.
2) There are oil filling cups at the main joints of the brake, and the oil filling should be checked every month.
3) In the case of a holding brake, ensure that the piston rod of the pusher extends about 10 mm.
4) Check and adjust the length of the brake spring frequently to ensure the correct braking torque.
5) When the thickness of the brake lining wears to the value in the table below, the brake lining should be replaced.
6) When the brake wheel is stained with oil, kerosene must be used to clean the surface of the brake wheel and the brake pad, and it can be used after it is dry.
7) For other contents, please refer to “Brake Operation Manual”.
1.4 Maintenance and maintenance of reel coupling
1) The reel coupling is lubricated with No. 2 lithium grease, and it is better to use No. 3 lithium grease under high temperature conditions. Oil should be filled once a month until the grease overflows.
2) There are baffles and fastening bolts at the output shaft end of the reducer, and the fastening bolts of the coupling and reel must be checked frequently.
3) For other contents, please refer to “WZL Reel Coupling Operation Manual”.
1.5 Maintenance and maintenance of wire rope
1) In order to prevent the wire rope from slackening and reducing its strength, the wire rope should be prevented from twisting and kinking when the grab is working.
2) The wire rope should be lubricated regularly. Before lubricating, clean the old oil with a rag soaked in kerosene. It is absolutely forbidden to clean the dirt on the wire rope with a metal brush or other sharp tools; it is absolutely forbidden to use acid or other corrosive lubricants.
3) The scrapping of the steel wire rope after wear is carried out according to the relevant national standards.
4) Check the connection and fixation of the wire rope and the drum once a month.
5) After replacing or moving the wire rope, the limit upper limit switch should be re-adjusted. The actual installation length of the steel wire rope is 44 meters. When replacing the steel wire rope, it is not necessary to adjust the lifting height limiter if the length of the new and old steel wire rope is the same as the two ends of the rope are fixed and the drum is not rotating.
1.6 Maintenance and maintenance of grab
1) Clean the hydraulic filter after the first start-up and work for about 50 hours.
2) The oil should be changed once after about 500 working hours of first use. Subsequent oil changes should be carried out after 10,000 working hours.
3) Regular inspection: oil level; plug connection and tension release device; hose and threaded joints and oil tank tightness; wire rope and grabbing bucket connection; system oil pressure (open: 120bar, closed 190bar).
4) When the grab bucket stops working, the power supply should be cut off to recover the piston rod to ensure that the grab bucket is in the open state.
5) Lubricate all lubrication points with lithium-based grease once a week.
6) For other content, please refer to the “Technical Documents” of Shanghai Qifan Pena Company.
1.7 Maintenance and maintenance of weighing device (load limiter)
The weighing device is composed of a sensor installed under the bearing seat of the reel and a monitoring computer installed in the control room.
1) After the adjustment of the weighing device is completed, non-maintenance personnel are not allowed to adjust any parts at will.
2) Check the change of the sensor zero point and alarm point every quarter, and adjust in time when problems are found to eliminate errors caused by component drift.
3) The load limiter is a safety protection device, and the safety operation rules should not be ignored because of the limiter.
4) Without permission, it is forbidden to enter the “calibration” state and adjust the calibration value.
5) For other content, please refer to the “Instruction Manual for Weighing and Testing System”
2. Maintenance and maintenance of the operating mechanism of large and small vehicles
1) The operating mechanism of the trolley is driven separately, and the brakes at both ends of the bridge frame must be adjusted to ensure that the two ends of the crane start and stop synchronously.
2) Wheel bearings should be kept in a good lubrication state, and the amount of oil should be 2/3 of the cavity of the bearing body.
3) When it is found that the bearing temperature is too high or the noise is too large, it must be stopped for inspection. Defective bearings should be replaced immediately.
4) Position encoders are installed on the driven wheel shafts of large and small vehicles, and their operation should be checked regularly.
5) The braking torque of the “three-in-one” reducer is fixed for the corresponding model. It has been adjusted before leaving the factory and marked with fire paint. Customers cannot adjust by themselves.
6) Regularly check the brake air gap of the “three-in-one” reducer, and adjust it to 0.2～0.5mm according to the model specifications.
7) Regularly check the wheels. If cracks, indentations and excessive wear are found, they should be repaired or replaced in time with reference to GB6067 “Safety Regulations for Cranes”.
3. Maintenance and maintenance of metal structures (bridge frame, trolley frame)
1) The crane bridge frame and its main components should be fully inspected at least once a year. The main contents of the inspection are as follows:
Check all connecting bolts, especially the connecting bolts of end beam joints, trolley frames or other parts, and pay great attention to them, and there must be no looseness.
Inspect the main welds, it is advisable to clean them with kerosene before inspection. If cracks are found in the weld, it should be removed and then welded with a high-quality welding rod to ensure the welding quality.
Check the deflection of the main beam to verify whether the main beam exceeds the specified deformation.
2) The metal structure of the crane should be painted once a year. Before painting, you should carefully remove old paint, rust stains, oil stains, etc., paint two layers, the first layer is anti-rust paint, and the second layer is top coat.
4. Maintenance and maintenance of the track
1) Frequently check the connection and fixing bolts of the running track of the crane and the trolley to ensure that there is no looseness.
2) Greasy is absolutely forbidden on the track. If necessary, fine sand can be sprinkled on the track to increase the friction coefficient.
3) When the track surface has waves in the high and low directions or the height difference between the two tracks on the same section is out of tolerance, it should be re-adjusted to meet the specified requirements.
4) When the rail side wear exceeds 15% of the original rail width, the rail must be replaced.
5. Maintenance and maintenance of limit switch
1) The crane is equipped with switches such as end beam door safety switch, lifting height limit, various extreme positions, and feeding port center to protect the safe operation of the crane. Especially the operation of the automatic control state plays a decisive role. The position and flexibility of various switches should be checked regularly to prove the reliability of the switches. In particular, switches such as brake opening limit and lifting limiter should be kept in their original positions after parts are worn or replaced.
2) Non-maintenance personnel are prohibited from touching various limit switches, especially directional limit switches, such as claw switches.
3) Drivers must not rely on limit switches to replace their normal operations.
6. Maintenance and maintenance of electrical equipment
The regulations of various maintenance periods are determined according to the crane’s working level and environmental conditions. The various maintenance systems listed below refer to general conditions. Users can make rules and regulations based on actual conditions.
Daily maintenance system: carried out by the crane driver when handing over shifts every day. The scope of overhaul is as follows:
Remove dust, oil and other attachments from the outside of electrical equipment. Use your hands to detect the heating of motors, contactors, controller contacts, resistors and other equipment. Check whether there is oil leakage in the bearing, and whether the wires and cable joints of the main equipment are tight. Check the operation of the brake motor. When opening the observation hole cover or enclosure, prevent foreign objects such as dust from entering the inside of the device. Record all the observations.
Ten-day maintenance (or bi-weekly maintenance): It is performed by the electrical staff, and the driver should also participate. The scope of the maintenance is as follows:
Remove dust, oil and other attachments inside electrical equipment. Observe whether the sounds of motors, contactors, relays and brakes are normal during operation, check and repair the contacts of the controller and the switch, level the contacts and apply a layer of petroleum jelly. Cooperate with mechanics to adjust the brake. Check the rodent damage in the cable trench.
Annual overhaul or overhaul: performed by electrical staff, the scope of overhaul is as follows:
Disassemble the electrical equipment for cleaning, and overhaul the brackets and fasteners of the electrical equipment. Check the protective layer of the wires and cables, clean the cable trench, and repair the holes in the cable trench that may cause rodent damage. Clean the rolling bearing of the motor and replace with new lubricating grease, measure the gap between the stator and the rotor, and replace the rolling bearing if it is found to be uneven. Measure the insulation resistance, (there are a large number of microelectronic devices inside the inverter and PLC, circuit isolation must be carried out when measuring the insulation with a megohmmeter) if necessary, dry it. All hidden dangers and defects must be repaired during the annual repair, and the parts that cannot be repaired should be replaced. The annual overhaul or overhaul should be determined by the actual wear and obsolescence of the various equipment, and don’t be too obsessed with time.
When using, pay special attention to the maintenance of the main contactors in the control cabinet, eliminate faults in time, keep the contacts smooth, clean, and normal pressure to check the reliability of the mechanical interlock.
A dry fire extinguisher must be provided on the crane, the most commonly used is a carbon tetrachloride fire extinguisher. Foam fire extinguishers are not allowed. Dry sand can only be used to extinguish the fire of the wire, but not to extinguish the fire of the motor.
When a fire occurs, first try to cut off the power supply. If other parts are on fire, use a main low-voltage circuit breaker to cut off the power supply. When the protection panel is on fire, the superior switch on the feeder should be cut off.
Cranes that have been on fire must be cleaned, dried and repaired, and all electrical equipment and electrical wiring must be repaired before they can be used.
Safety technical rules for electrical equipment maintenance:
1) Only professionals are allowed to perform electrical maintenance of cranes, and record the date, name, cause of the electrical failure, repair method, and actual maintenance problems at any time.
2) If the shell or protective cover of conductive parts and bare wires is incomplete, cranes are not allowed.
3) Portable lighting lamps with voltage below 36V must be used for repairs.
4) When working with electricity, be sure to wear rubber gloves, rubber boots and use tools with insulated handles. In addition, a dedicated person should immediately cut off the power supply in the event of danger. All places close to conductive parts must be fenced off.
5) All metal parts on motors, electrical equipment and electrical enclosures that may conduct electricity must be grounded.