1. What is the maximum lifting weight and load center? What is their relationship?
Answer: When the center of gravity of the cargo is on the same vertical line as the load center, the maximum weight that the forklift can handle is called the maximum lifting capacity of the forklift; the horizontal distance from the center of gravity of the standard load to the front wall of the vertical section of the fork is called the load center of the forklift . Generally, the load center is specified in the design according to the standard, that is, the forklifts with different lifting weights generally have different load centers. When the center of gravity of the cargo is within the range of the load center, the forklift can carry out loading and unloading operations with the maximum lifting weight, otherwise the stability of the forklift will be damaged and accidents are likely to occur.
2 What is the stability of a forklift?
Answer: The stability of the forklift refers to the forklift's ability to resist tipping when loading and unloading and driving on various roads. It can be divided into longitudinal stability and lateral stability. Longitudinal stability refers to the ability of the forklift to resist longitudinal rollover around the axle. Lateral stability refers to the forklift's ability to resist rollover and slip.
3. How should the fork and mast be parked after the forklift works?
Answer: After the forklift is working, the fork must be lowered to the ground, and the mast must be restored to its original position (center vertical). The purpose is to allow the hydraulic system to obtain unloading protection to avoid deformation and damage of various components (especially sealing components) in the hydraulic system due to long-term compression.
4. What are the reasons for forklift gantry shaking and gantry automatic forward and backward tilt?
Answer: The reason for jitter:
(1) The gap between the support pin of the mast and the copper sleeve is too large
(2) The gap between the sliding steel plates of the inner and outer masts is too large
(3) The two start chains are not tight
(4) Excessive wheel wear
Reasons for automatic forward and backward tilt:
(1) Damage to the oblique tilt cylinder seal
(2) Multi-way valve sink
5. What is the reason for the automatic decline after the fork is lifted?
Answer: (1) The piston cup is aging or damaged
(2) The gap between the lifting cylinder and the piston is too large
(3) The gap between the lifting valve cylinder and the lifting valve stem of the hydraulic distributor is too large
(4) Pipeline or joint oil leakage
6. What is the reason why the fork lift speed is too slow and cannot be lifted?
Answer: The reason for the slow rise:
(1) Oil pump wear or oil leakage
(2) The spring pressure of the distributor safety valve is too low or the steel ball and the valve seat are worn
(3) The gap between the distributor's lifting valve cylinder and the lifting valve stem is too large
(4) The clearance between the lifting cylinder and the piston is too large, or the leather cup is aging or damaged
(5) Pipeline or joint oil leakage
(6) One-way throttle valve is not working
The reason why the fork cannot lift
(1) Fuel tank is short of oil
(2) The oil pipe joint is blocked or serious oil leakage
(3) The oil pump is damaged
(4) The safety valve spring is broken or permanently deformed
7. What are the types of forklift maintenance? What is the time interval?
Answer: The maintenance of the forklift is divided into four categories, namely daily maintenance, first-level maintenance, second-level maintenance, and third-level maintenance. Routine maintenance is maintenance performed every day, usually after every 50 hours of work, first-level maintenance, every 200 hours of second-level maintenance, every 600 hours of third-level maintenance.
8. What is the daily maintenance content of the forklift?
Answer: The specific contents are:
(1) Check the amount of engine oil in the engine crankcase and air filter, the amount of fuel in the fuel tank and the amount of cooling water in the radiator. If insufficient, add as required.
(2) Check the height of the electrolyte surface in the battery, add as necessary, and keep the air holes of the cover open, and the pole and wire joint are tightly and firmly connected.
(3) Check the free travel and working reliability of the hydraulic brake and hand brake, and add brake fluid and remove the air in the system as necessary.
(4) Check the visual tire pressure and remove debris embedded in the tread.
(5) Check the working oil volume, pipelines and joints in the hydraulic tank of the vehicle for leaks.
(6) Check the water level of the fire water tank.
(7) Check the working conditions of instruments, lights, speakers, etc.
(8) After the above inspections are completed, start the engine, check the operation of the engine, and check whether the operation of the drive train, brake system and hydraulic lifting system is normal.
9. What is the main content of the first-level maintenance of the forklift?
Answer: (1) Check the engine oil quantity, engine oil viscosity and the degree of dirt in the engine oil.
(2) Clean the battery and add distilled water if necessary.
(3) Check the appearance and tightness of the fan belt.
(4) Check the gearbox, drive axle, working oil pump, and water pump drive for abnormal noise.
(5) Add oil or grease to the clutch and brake longitudinal connecting rods as required.
(6) Check the abrasion of the piston rod of the lifting cylinder and the tilting cylinder. If there are slight scratches, use oil stone or fine sand cloth to smooth it.
(7) Check and tighten the bolts and nuts of the tire.
10. What is the main operation content of the secondary maintenance of the forklift?
Answer: (1) Clean the engine oil pan, crankcase and oil filter, and replace with new oil.
(2) Clean the fuel tank and check if there is any looseness or oil leakage in the connection between the fuel pipeline and the fuel pump.
(3) Check the power-off contacts of the distributor and adjust the period gap.
(4) Check and tighten the bolts of each exposed part of the generator.
(5) Check the discharge capacity of the battery and charge it if necessary.
(6) Replace the cooling water in the radiator.
(7) Check and adjust the free travel of the clutch and brake pedal and the braking clearance of the wheel brake.
(8) Drain the sediment and accumulated water at the bottom of the working oil tank, clean the filter and add new oil as appropriate.
(9) Check whether the tightness of the two heavy chains is consistent.
(10) Check whether there is any deformation or cracks on the forklift truck iron and fork heel.
11. What is the main operation content of the three-level maintenance of the forklift?
Answer: (1) Adjust the valve clearance.
(2) Measure cylinder pressure and check the cause of unsatisfactory.
(3) Check the working performance of the clutch and adjust it if necessary.
(4) Check the free travel of the steering wheel and the connection of the steering tie rod, and check the wear condition of the knuckle pin and the steering sector arm pin shaft.
(5) Check the clutch and brake pedal shaft bearings for wear.
(6) Clean the forklift in an all-round way, and inspect and tighten all bolts and nuts in the exposed parts.
12. What are the safe operation rules of the forklift?
Answer: (1) Check the vehicle
(1) Before operating the forklift, check the appearance and fill with fuel, lubricating oil and cooling water.
(2) Check the starting, running and braking performance.
(3) Check whether the lights and sound signals are complete and effective.
(4) Check whether the pressure and temperature are normal during the operation of the forklift.
(5) After the forklift is in operation, the external leakage should be checked and the seals should be replaced in time.
(6) In addition to checking the above content, the battery forklift should also check the circuit of the battery forklift according to the relevant inspection content of the battery forklift.
(2) Start
(1) Before starting, observe the surrounding area and confirm that there are no obstacles that hinder driving safety, then whistle first and then start.
(2) For vehicles with pneumatic braking, the brake air pressure gauge reading must reach the specified value before starting.
(3) When the forklift starts to load, the driver should first confirm that the loaded goods are stable and reliable.
(4) Start slowly and smoothly.
(3) Driving
(1) When driving, the height of the bottom of the fork from the ground should be kept 300-400mm, and the mast must be tilted backwards.
(2) Do not raise the fork too high while driving. When entering or leaving the job site or driving, pay attention to the sky without obstacles. When the load is traveling, if the fork rises too high, it will also increase the overall height of the forklift's center of gravity, affecting the stability of the forklift.
(3) After unloading, the fork should be lowered to the normal driving position before driving.
(4) When turning, if there are pedestrians or vehicles nearby, it should send a signal and prohibit high-speed sharp turns. High-speed sharp turns can cause the vehicle to lose lateral stability and tip over.
(5) The internal combustion forklift is strictly prohibited from turning off and sliding when descending.
(6) For non-special circumstances, it is forbidden to brake hard while driving.
(7) When the load travels more than 7 degrees and goes up and down at a speed higher than the first gear, the brakes shall not be used under special circumstances.
(8) When the forklift is in operation, it must abide by the traffic rules in the factory, and must maintain a certain safety distance from the front vehicle.
(9) When the forklift is in operation, the load must be at the lowest position that does not hinder driving. The mast must be properly tilted back, and the load must not be increased during stacking or loading. When transporting huge objects, the objects block the driver's sight, and the forklift should be turned upside down.
(10) The forklift is steered by the rear wheels, so you must always pay attention to the swing of the rear of the car to avoid the sharp turns that beginners often have when driving.
(11) It is forbidden to turn on slopes or drive across slopes.
(12) When the forklift truck is going downhill, it should drive backwards to prevent the goods from falling.
(4) Loading and unloading
(1) When loading items on forks, the spacing between the two forks should be adjusted as necessary to balance the load on the two forks without deflection. The side of the article should be against the shelf, and the weight of the fork should conform to the requirements of the load center curve sign.
(2) The height of the load must not obstruct the driver's sight.
(3) During the loading and unloading of articles, the forklift must be braked with brakes.
(4) When the forklift is approaching or evacuating items, the speed should be slow and steady. Be careful not to crush the items, wooden mats, etc. on the wheels to prevent the crushed objects from flying and hurting people.
(5) When picking up goods with a fork, the fork should be as deep as possible under the load, and also pay attention to that the tip of the fork cannot touch other goods or objects. The minimum mast tilt should be used to stabilize the load to prevent the load from sliding back. When lowering the load, the mast can be tilted forward by a small amount to facilitate the placement of the load and extraction of the fork.
(6) It is forbidden to fork the goods at high speed and collide with hard objects with fork heads.
(7) When the forklift is operating, it is forbidden to stand on the fork.
(8) Forklifts and forks work, it is forbidden for people to stand around the forks to prevent the goods from collapsing and hurting people.
(9) It is forbidden to use credit forks to lift people to work in high places, so as to avoid falling accidents in high places.
(10) It is not allowed to use the braking inertia to slide objects.
(11) It is not allowed to fork the cargo on the ship directly on the shore of the dock.
(12) The use of single fork operations is prohibited.
(13) Overload operation is prohibited.
13. What are the safety technical conditions of the forklift crane structure?
Answer: (1) The door frame must not be deformed and the weld seam should be unwelded. The rolling gap between the inner and outer door frames should be adjusted reasonably, not more than 15mm, the rolling rotation should be flexible, and the wheel and shaft should be free of cracks and defects. The amount of wheel groove wear shall not be greater than 10% of the original size.
(2) The tension of the two lifting chains should be even, without distortion, the ends should be connected firmly, and the pitch of the chain should not exceed 4% of the length, otherwise the chain should be replaced. The sprocket rotation should be flexible.
(3) The fork frame must not be severely deformed; the surface of the fork must not be cracked; the welds of all parts must not be de-welded, the root angle of the fork must not be greater than 93%, and the thickness must not be less than 90% of the original size; The height difference should not exceed 3% of the length of the horizontal section of the fork; the positioning of the fork should be reliable, the bearing surface and positioning surface of the fork hook must not have obvious defects; the cooperation gap between the fork and the fork frame should not be too large, and the movement should be smooth .
(4) The joint part of the lifting cylinder and the gantry should be firm, the hinge connection of the tilting cylinder and the gantry, and the frame should be firm and flexible, and the cooperation clearance should not be too large. The oil cylinder should be well sealed, without cracks, and work smoothly. Under the rated load, the self-sinking amount of the 10min portal frame is not more than 20mm, and the inclination angle is not more than 0.5 degrees. The lifting speed at full load is not less than half of the standard value.
14. What are the safety technical conditions for the hydraulic control system of the forklift?
Answer: (1) The joints of the hydraulic system pipelines are firm, without leakage, and are not worn with other mechanical parts, and the rubber hoses must not be aged or deteriorated.
(2) Transmission components in the hydraulic control system should not co-occur with crawling, stagnation and obvious impulse within the rated load and rated speed.
(3) The casing of the multi-way reversing valve is free of cracks and leakage. The working performance is good and reliable; the safety valve is sensitive and should be fully opened when the overload is 25%, and the nut of the adjustment bolt should be fully tightened. The operating handle is positioned accurately and reliably, and must not be displaced due to vibration.
(4) The load curve and hydraulic control nameplate should be complete and fresh.
15. What to know about full hydraulic forklift
(1) The amount of torque converter oil needs to be marked with a dipstick. Add enough torque converter oil. No. 8 liquid-lift transmission oil in winter No. 22. Summer steam turbine oil No.
(2) The normal working oil temperature of the torque converter is 90 degrees ± 10 degrees.
(3) The oil temperature needs to be cooled by the vehicle to 100 degrees. So as not to affect the performance and life of the vehicle.
(4) The pressure of the torque converter gear is 12 ± 1 kg. Excessive pressure will affect the performance and life of the work.
