1. What is the maximum lifting capacity and load center? What is their relationship?
Answer: when the center of gravity of the goods and the load center are in the same vertical line, the maximum weight that the forklift can load and unload goods is called the maximum lifting weight of the forklift; The horizontal distance between the center of gravity of the standard load and the front wall of the vertical section of the forklift is called the load center of the forklift. Generally, the load center is specified in the design according to the standard, that is, the load centers of forklifts with different lifting weights are generally different. When the center of gravity of the goods is within the load center, the forklift can carry out loading and unloading with the maximum lifting capacity, otherwise the stability of the forklift will be damaged and accidents will easily occur.
2 what is forklift stability?
Answer: the stability of forklift refers to the ability of forklift to resist overturning during loading and unloading and driving on various roads. It can be divided into longitudinal stability and transverse stability. Longitudinal stability refers to the ability of a forklift to resist longitudinal overturning around the axle. Lateral stability refers to the ability of a forklift to resist rollover and sideslip.
3. How to stop the forks and gantry after forklift operation?
Answer: after the forklift works, the forklift must be lowered to the ground, and the gantry must be restored to its original position (vertical in the middle). The purpose is to obtain unloading protection for the hydraulic system, so as to avoid deformation and damage of various components (especially sealing components) in the hydraulic system due to long-term pressure.
4. What are the reasons for the shaking of the forklift gantry and the automatic forward and backward tilting of the gantry?
Answer: causes of jitter:
(1) The clearance between the portal support pin shaft and the copper sleeve is too large
(2) Excessive clearance between sliding steel plates of inner and outer door frames
(3) Two starting chains differ in tightness
(4) Excessive wear of roller
Causes of automatic tilt back and forth:
(1) The seal of tilt cylinder is damaged
(2) Multi way valve manifold leakage
5. What is the reason for the fork to slide automatically after lifting?
Answer: (1) the piston cup is aged or damaged
(2) Excessive clearance between lifting cylinder and piston
(3) The clearance between lifting valve barrel and lifting valve rod of hydraulic distributor is too large
(4) Oil leakage in pipeline or joint
6. What is the reason why the fork lifting speed is too slow and cannot be lifted?
Answer: reasons for slow lifting:
(1) Worn or leaking oil pump
(2) The spring pressure of distributor safety valve is too low or the steel ball and valve seat are worn
(3) The clearance between the lifting valve barrel of the distributor and the lifting valve rod is too large
(4) The clearance between the lifting cylinder and the piston is too large, or the leather cup is aged or damaged
(5) Oil leakage in pipeline or joint
(6) One way throttle valve fails to work
Reasons why forks cannot be lifted
(1) Oil tank is short of oil
(2) The oil pipe joint is blocked or has serious oil leakage
(3) Oil pump damaged
(4) Safety valve spring is broken or permanently deformed
7. What are the types of forklift maintenance? What is the time interval?
Answer: forklift maintenance is divided into four categories, namely, daily maintenance, first level maintenance, second level maintenance and third level maintenance. Daily maintenance is a daily maintenance. Usually, the first level maintenance is carried out after every 50 hours of operation, the second level maintenance is carried out after every 200 hours of operation, and the third level maintenance is carried out after every 600 hours of operation.
8. What is the daily maintenance of forklift truck?
Answer: the specific contents include:
(1) Check the oil quantity in the engine crankcase and air filter, the fuel quantity in the fuel tank and the cooling water quantity in the radiator. If it is insufficient, add it as required.
(2) Check the height of the electrolytic liquid level in the battery, add it if necessary, keep the air hole of the cover unblocked, and ensure that the pole is firmly connected with the wire connector.
(3) Check the free stroke and working reliability of the hydraulic brake and hand brake, fill the brake fluid and remove the air in the system as necessary.
(4) Check the tire pressure and remove the sundries embedded in the tread.
(5) Check the working oil volume in the oil tank of the vehicle hydraulic system and whether there is leakage at the pipeline, joint, etc.
(6) Check the water level of the fire extinguishing water tank.
(7) Check the operation of instruments, lights, horns, etc.
(8) After the above inspections, start the engine, check the operation of the engine, and check whether the transmission system, braking system, hydraulic lifting system and other systems work normally.
9. What are the main contents of forklift level I maintenance?
Answer: (1) check the oil quantity, oil viscosity and dirt level in the engine oil.
(2) Clean the battery and add distilled water as necessary.
(3) Check the appearance and tightness of the fan belt.
(4) Check the gearbox, drive axle, working oil pump and water pump driving device for abnormal noise.
(5) Fill oil or grease at each part of the clutch and brake longitudinal connecting rod as required.
(6) Check the wear of the piston rod of the lifting cylinder and the tilt cylinder. If there is a slight scratch, it can be polished with an oilstone or a fine abrasive cloth.
(7) Check and tighten the bolts and nuts of the tire.
10. What are the main operation contents of forklift secondary maintenance?
Answer: (1) clean the engine oil pan, crankcase and oil filter, and replace with new engine oil.
(2) Clean the fuel tank and check whether the joints of the fuel pipeline and the oil pump are loose or leaking.
(3) Check the power distributor cut-off contact and adjust the interval clearance.
(4) Check and tighten the bolts at all exposed parts of the generator.
(5) Check the discharge of the battery and charge it if necessary.
(6) Replace the cooling water in the radiator.
(7) Check and adjust the free stroke of clutch and brake pedal and the brake clearance of wheel brake.
(8) Discharge the settled sundries and accumulated water at the bottom of the working oil tank, clean the filter screen and add new oil as appropriate.
(9) Check whether the tightness of the two lifting chains is consistent.
(10) Check whether there is deformation and cracking on the iron block of the forklift and the heel of the forklift.
11. What are the main operation contents of forklift three-level maintenance?
Answer: (1) adjust the valve clearance.
(2) Measure the cylinder pressure and check the cause of nonconformity.
(3) Check the working performance of the clutch and adjust it as necessary.
(4) Check the free stroke of the steering wheel and the connection of the steering tie rod, and check the wear of the steering knuckle pin and the pin shaft of the steering sector boom.
(5) Check the bearing wear of clutch and brake pedal shaft.
(6) Thoroughly clean the forklift, and check and tighten the bolts and nuts at all exposed parts.
12. What are the safety operating procedures for forklifts?
Answer: (I) check the vehicle
(1) Before forklift operation, the appearance shall be checked and fuel, lubricating oil and cooling water shall be filled.
(2) Check startup, operation and braking performance.
(3) Check whether the light and sound signals are complete and effective.
(4) During the operation of forklift, check whether the pressure and temperature are normal.
(5) After the forklift is operated, the external leakage shall be checked and the seals shall be replaced in time.
(6) In addition to the above contents, the battery forklift shall also check the circuit of the battery forklift according to the relevant inspection contents of the battery forklift.
（2） Start
(1) Before starting, observe the surrounding area and confirm that there are no obstacles hindering driving safety, then whistle first and then start.
(2) For air braked vehicles, the brake barometer reading must reach the specified value before starting.
(3) When the forklift starts with load, the driver should first confirm that the load is stable and reliable.
(4) Start slowly and steadily.
（3） Driving
(1) When driving, the height between the bottom of the fork and the ground shall be kept 300-400mm, and the gantry shall be tilted back.
(2) Do not raise the fork too high while driving. When entering or leaving the operation site or driving, pay attention to whether there are obstacles above. When the load is moving, if the fork is raised too high, the overall center of gravity height of the forklift will be increased, which will affect the stability of the forklift.
(3) After unloading, lower the fork to the normal driving position before driving.
(4) When turning, if there are pedestrians or vehicles nearby, send a signal and prohibit sharp turning at high speed. Sharp turns at high speeds can cause the vehicle to lose lateral stability and roll over.
(5) It is strictly forbidden for the internal combustion forklift to stall and slide down the slope.
(6) It is forbidden to brake suddenly when the vehicle is moving with load except for special circumstances.
(7) The brake shall not be used except under special circumstances when the load is driven over 7 degrees and the speed is higher than the first gear.
(8) The forklift shall comply with the traffic rules in the plant and must keep a certain safe distance from the front vehicle.
(9) When the forklift is running, the load must be at the lowest position that does not interfere with driving. The gantry shall be properly tilted back. The load shall not be raised except when stacking or loading. When handling large objects, the objects block the driver's line of sight. At this time, the forklift should be reversed.
(10) The forklift is steered by the rear wheel, so it is necessary to pay attention to the swing behind the forklift at all times to avoid the phenomenon that beginners often turn too fast when driving.
(11) It is forbidden to turn on the ramp or drive across the ramp.
(12) When the forklift is carrying goods downhill, it should be driven backwards to prevent the goods from falling.
（4） Loading and unloading
(1) When forking articles, the space between the two forks shall be adjusted as required to balance the load of the two forks without deflection. One side of the article shall be close to the shelf. The weight of the forks shall comply with the provisions of the load center curve signboard.
(2) The height of the load shall not obstruct the sight of the driver.
(3) During the loading and unloading of articles, the forklift must be braked with brakes.
(4) When the goods forklift approaches or evacuates the goods, the vehicle speed shall be slow and stable, and the wheels shall not crush the goods, wooden mats, etc., so as to avoid flying the crushed goods and injuring people.
(5) When taking goods with a fork, the fork should be as deep as possible under the load, and the fork tip should not touch other goods or objects. The load shall be stabilized with a minimum gantry tilt back to prevent the load from sliding backwards. When releasing the load, the gantry can be tilted forward a small amount to facilitate the placement of the load and the withdrawal of the fork.
(6) It is forbidden to pick up goods at high speed and collide with hard objects with fork heads.
(7) During forklift operation, it is forbidden to stand on the forklift.
(8) During forklift operation, personnel are not allowed to stand around the forks to avoid injury caused by the collapse of goods.
(9) It is forbidden to lift personnel with forks for high-altitude operation to avoid falling accidents.
(10) It is not allowed to use braking inertia to slip objects.
(11) It is not allowed to fork load the goods directly on the quay.
(12) Single fork operation is prohibited.
(13) Overload operation is prohibited.
13. What are the safety technical conditions for forklift lifting mechanism?
Answer: (1) the gantry shall be free of deformation and weld desoldering. The rolling gap between the inner and outer gantry shall be adjusted reasonably, which shall not be greater than 15mm. The rolling rotation shall be flexible, and the roller and shaft shall be free of cracks and defects. The wear of the wheel groove shall not be greater than 10% of the original size.
(2) The tension of the two lifting chains shall be uniform without distortion, the ends shall be firmly connected, and the pitch of the chain shall not exceed 4% of the length, otherwise the chain shall be replaced. The sprocket shall rotate flexibly.
(3) The fork frame shall not be seriously deformed; The fork surface shall be free of cracks; The welds of all parts shall be free of desoldering, the fork root angle shall not be greater than 93%, and the thickness shall not be less than 90% of the original size; The height difference between the left and right fork tips shall not exceed 3% of the length of the horizontal section of the fork; The positioning of the fork shall be reliable, and the supporting surface and positioning surface of the fork hook shall not have obvious defects; The fit clearance between the fork and the fork frame shall not be too large, and the movement shall be smooth.
(4) The connecting parts of the lifting cylinder and the gantry shall be firm, and the articulation of the tilt cylinder and the gantry and frame shall be firm and flexible, and the matching clearance shall not be too large. The oil cylinder shall be well sealed, free of cracks and stable. Under the rated load, the self sinking amount of gantry in 10min shall not be greater than 20mm, and the inclination angle shall not be greater than 0.5 °. The lifting speed at full load shall not be less than half of the standard value.
14. What are the safety technical conditions for forklift hydraulic control system?
Answer: (1) the hydraulic system pipe joints shall be firm without leakage, and shall not be worn with other parts. The rubber hoses shall not be aged or deteriorated.
(2) The transmission components in the hydraulic control system shall not creep, stagnate or have obvious impulse within the range of rated load and rated speed.
(3) The multi-channel directional valve shell shall be free of cracks and leakage. Good and reliable working performance; The safety valve acts sensitively and can be fully opened when it is overloaded by 25%. The nuts of adjusting bolts shall be complete and fastened. The operating handle shall be positioned accurately and reliably, and shall not be displaced due to vibration.
(4) Load curve and hydraulic control nameplate shall be complete and fresh.
15. Full hydraulic forklift
(1) For the torque converter oil quantity, add enough torque converter oil as indicated by the dipstick 8 l transmission oil winter 22 Summer 30 turbine oil.
(2) The normal operating oil temperature of the torque converter is 90 ± 10 degrees.
(3) When the oil temperature reaches 100 ℃, the vehicle shall be stopped for cooling. So as not to affect the performance and service life of the vehicle.
(4) The torque converter gear pressure is 12 ± 1kg. Excessive pressure will affect the working performance and service life.
