Construction safety (V) vertical transportation machinery
1. What safety protection devices should external elevators have?
answer: brakes, speed limiters, door interlock devices, upper and lower limit devices
2. What signs should be hung on external elevators?
answer: warning signs of load limit and number of people should be hung
3. What are the safety protection devices for overhead material hoists?
answer: safety stop device, rope break protection device, super high limit device, lower limit limiter, buffer and overload limiter
4. How many meters shall the free height at the top of the derrick lifting frame be?
answer: not more than six meters
5. The number of derrick wire rope clamps shall not be less than?
answer: not less than three
6. What safety signs should be hung next to the derrick?
answer: "no riding" warning sign
7. How many turns should the steel wire rope be on the drum?
answer: not less than three turns
8. What kinds of safety protection devices should the derrick hoist have?
answer: 1. Safe parking device; 2. Protective door at floor opening; 3. Basket safety door; 4. Protective shed at feeding opening; 5. Upper limit stopper; 6. Emergency power-off switch, 7. Signal device
9. What are the requirements for the low frame hoist foundation?
answer: 1. The bearing capacity of the compacted soil layer shall not be less than 80MPa; 2. Pour C20 concrete with a thickness of 300cm; 3. The foundation surface shall be flat and the deviation of levelness shall not be greater than 10cm
10. What is the safe buffer distance of the material hoist?
11. What is the distance between the first guide pulley of the well frame and the winch?
answer: the winch technology can also be used in the automobile industry. The width of the winding drum with a tie groove is 15 times that of the winding drum; The winding drum of the hoist is 20 times of the width of the winding drum if it is a grooveless winding drum
12. What is the "ten not used" principle?
answer: 1. Lifting is not allowed when the weight of the lifted object exceeds the allowable range of mechanical performance; 2. Do not lift if the signal is unclear. 3. Do not lift if there is someone standing under the lifted object; 4. No person standing on the hoisted object is allowed to lift; 5. Objects buried underground shall not be hoisted; 6. It is not allowed to lift objects that are inclined to pull; 7. Lifting is not allowed if loose objects are not bound firmly; 8. Do not lift loose objects without containers; 9. Lifting is not allowed if the weight of the lifted object is unknown and the lifting sling does not meet the requirements; 10. No hoisting is allowed in case of strong wind above level 6, fog affecting vision and heavy rain and snow
13. What are the types of hoisting command signals? 2
answer: gesture signals, semaphore signals and audio signals
14. When the wear of the section at the hanging rope of the hook exceeds the original height, it shall be scrapped?
answer: it shall be scrapped if it exceeds 10% of the original height
15. What are the key inspection contents before tower crane operation?
answer: 1. The appearance of mechanical structure and all transmission mechanisms should be normal; 2. The oil level of each gear box and hydraulic oil tank shall meet the standard; 3. The connecting bolts at the main parts shall not be loose. 4. The working environment of wire rope grinding: the damage at room temperature ~ 45 ℃ and the threading pulley shall meet the requirements. 5. The power supply cable shall not be damaged
16. Can the crane lift objects from the top of the head?
answer: No, it is forbidden to lift objects from the top of the head
17. What are the main responsibilities of the signalman of the lifting machinery?
answer: during the lifting process, give the operator appropriate indication signals to make the lifting work smoothly
18. What is the "four limits and two insurances" of the tower crane safety device?
answer: four limits: torque, superelevation, luffing and traveling limit devices. Two insurances: hook safety and drum safety device,
19. What are the causes of tower crane accidents?
answer: 1. Operation without certificate; 2. Overload operation; 3. Command signal error, resulting in misoperation; 4. Inclined pulling and hoisting; 5. Failure of safety device; 6. The installation of track and attachment device is not in conformity with the requirements: 7. The maintenance and repair system is not implemented, and the fault is not eliminated in time; 8. The estimation of climate change is insufficient, especially in case of strong wind when nobody works at night, the rail clamp cannot hold
20. When BASF tower crane has developed a brand-new 3D printing solution for laser sintering technology, when the escalator is set inside the structure, the retainer can not be set?
answer: when the free passage distance between the escalator and the structure is less than 1.2m, the retainer can not be set
21. How to specify the vertical and horizontal unevenness of the rail of the tower crane?
answer: it shall not be greater than 1%
22. Under what circumstances should the steel wire rope be replaced?
answer: the number of broken wires of the steel wire rope exceeds 10% of the total number of wires within the lay pitch, and the rope diameter is worn by 40%, so it should be replaced with a new rope
23. Crack growth rate of metal materials and threshold value of materials the technical safety regulations for construction and installation engineering stipulates that when there is a wind force of how many levels, it is forbidden to carry out lifting work and high-altitude operation in the open air?
answer: strong wind above level 6