Basic knowledge of the hottest crane III

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Basic knowledge of cranes (III)

1 cranes include cranes, which are part of cranes

2 truck crane and tire crane are completely different:

truck crane is a kind of crane that installs the crane on the truck chassis In recent years, due to the continuous improvement of truck load capacity and the emergence of various special truck chassis, large tonnage truck cranes are constantly emerging. Because the hydraulic mechanism is widely used in truck cranes, using high-strength steel as the boom of the crane, it has many advantages in both operation and performance Therefore, truck crane is the most widely used crane at present

the tire crane is installed on the chassis composed of heavy tires and axles, and is equipped with four outriggers It is evolved from the crawler crane, which turns the crawler and walking support of the walking mechanism into a chassis with tires, which overcomes the defect that the crawler shoes of the crawler crane cause damage to the road surface, and the traveling speed is faster than that of the crawler crane The four outriggers erected by the tire crane enhance the stability of the crane during hoisting operations Its lifting capacity is relatively large, and it can rotate 360 degrees in any direction, but when lifting, outriggers are required to increase the stability of the crane When working without outriggers or lifting materials, it is difficult to walk, so the lifting weight needs to be reduced It must be ensured that the operation of road guarantee machinery is an important operation of the effectiveness subsystem, the rotation is smooth and solid, the tire pressure must meet the requirements, and the load must be carried out in accordance with the provisions of the original locomotive performance At the same time, the weight shall not be lifted more than 50cm from the ground, and the sliding rope shall be fastened to drive slowly It is forbidden to walk long distances with load

safety standard for bridge crane

a trial operation of bridge crane (no-load test, overload test, dynamic load test)

1 check the connection of each mechanism to see whether it is firm

2 check whether the wire rope is threaded correctly in the drum and pulley

3 check whether the insulation of all electrical parts is good, whether the limit switches and their safety facilities are complete, whether the wiring is correct, and whether the action of electrical components is accurate and reliable

4 check whether the brake is sensitive and reliable

5 prepare the trial weight of the specified weight

b no-load test

first, switch on the power supply, try to operate the control device, and then make each mechanism run slowly and gradually accelerate to a fixed speed. At this time, the operation of each transmission component should be stable without impact and vibration. If there is any abnormality, stop the machine immediately for adjustment. During the test, all mechanisms should run repeatedly for 2-3 times

the test operation of lifting mechanism and operating mechanism shall not be less than 10 minutes

all switches must be tested, including hook rising limit switch, crane running end limit switch, trolley running end limit switch, hatch cover switch, barrier door switch, cab door interlock switch and emergency switch, which should be sensitive and reliable

c overload test

drive the trolley to the middle of the main beam, hoist 0.5 times the load first, and then 0.7 times if there is no problem. At this time, the lower disturbance of the bridge should not exceed 1/700 of the bridge span. If there is no problem, hoist 1.25 times the rated load again, hoist 100 mm off the ground, stay for 10 minutes, and then remove the load. Repeat this for three times, and plastic deformation is not allowed

d dynamic load test

hoist 1.1 times of the rated load to make the trolley run back and forth on the main beam for several times. When there is no problem, start the two mechanisms at the same time to run repeatedly, and the number of runs should not be less than 10. At this time, all mechanisms of the crane should operate normally

gantry crane knowledge

double beam bridge crane operating procedures

2.33.1 before work

a. check the brake, hook, wire rope, safety device and other parts according to the requirements of the spot check card. If any abnormal phenomenon is found, it should be eliminated

b. the operator can turn on the main power supply only after confirming that there is no one on the platform or track. When the power circuit breaker is locked or has a notice board, the original relevant person should remove it before closing the main power supply

2.33.2 work

a. when lifting a heavy object for the first time in each shift (or when the load reaches the maximum weight), the heavy object should be lowered again after being lifted 0.5 meters above the ground, and the brake performance should be checked. Normal operation can be carried out after it is confirmed to be reliable

b. during operation, the operator shall ring the bell for the following operations as required

① lifting and lowering heavy objects; When driving large and small cars

② when the crane passes through with unclear sight, it should ring the bell continuously to give an alarm

③ when the crane approaches another crane in the span

④ when lifting heavy objects close to personnel

c. the operation shall be carried out according to the unified command signal

d. in case of sudden power failure during operation, all controller handles should be set to the "zero" position, and the crane action should be checked before re operation

c. it is strictly forbidden to turn on the reverse brake to stop the crane and trolley during normal operation; When changing the moving direction of the crane and trolley, the handle must be placed in the "zero" position, and the reverse driving can be carried out only after the mechanism is completely stopped

d. for cranes with two hooks, when the main and auxiliary hooks are replaced and the height of the two hooks is similar, the main and auxiliary hooks must be operated separately to prevent the two hooks from colliding

e. cranes with two hooks are not allowed to lift two objects at the same time; Adjust the hoist brake when it is not working

f. do not use the limit position limiter to stop, and do not adjust the brake of the lifting mechanism under load

g. strictly implement the "ten no lifting" system:

it is composed of Dow and DuPont's agricultural plates

① do not lift if the command signal is unclear or disorderly

② do not lift when the rated lifting capacity is exceeded

③ do not lift if the use of lifting appliances is unreasonable or the objects are not tied firmly

④ do not lift when there are people or other floating objects on the lifting object

⑤ do not lift if the holding brake or other braking safety devices fail

⑥ do not lift when the crane suspends the heavy object for direct processing

⑦ pull askew and hang askew without lifting

⑧ do not lift explosive objects

⑨ objects buried underground shall not be lifted

⑩ don't lift objects with edges and corners without padding

h. in case of any abnormality, stop the machine immediately, check the cause and eliminate it in time

2.33.3 after work

a. raise the hook to a certain height, stop the crane and trolley at the specified position, and set the controller handle to the "zero" position; Pull down the switch handle of the protection box and cut off the power supply

b. carry out daily maintenance

c. do a good job of shift handover

2.34 operating procedures for single beam bridge crane

2.34.1 before work

a. before the single beam bridge crane with cab and the driver takes over the shift and starts driving, the hook, steel wire rope, safety device and other parts shall be checked according to the requirements of the spot inspection card, and any abnormal conditions shall be eliminated

b. for the single beam bridge crane operated on the ground, each shift should have a special person responsible for checking according to the requirements of the spot check card, and any abnormal conditions should be eliminated

c. the operator can turn on the main power supply only after confirming that there is no one on the platform or track. When the power circuit breaker is locked or has a notice board, the original relevant person should remove it before closing the main power supply

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