3.3.1 Size requirements
The ratio D/d of the minimum nominal diameter of pulleys, drums, and balance pulleys to the nominal diameter of the wire rope shall meet the requirements of GB3811-83.
The flange on the side of the drum exceeds the height of the outermost wire rope during work and should not be less than 2 times the nominal diameter of the wire rope.
3.3.2 Scrap
Drums and pulleys with one of the following conditions should be scrapped:
a. Cracks or rim damage;
b. The wall of the reel is reduced by 10% compared to the original thickness;
c. The wall thickness of the rope groove of the pulley is worn up to 20%;
d. Wear of the bottom of the pulley groove exceeds 25% of the diameter of the wire rope.
3.4 hook

3.4.1 The manufacture of hooks should comply with the hook standards. This standard is still under development. .
3.4.2 Repair welding of hooks is forbidden, and it should be scrapped in any of the following situations:
a. Use a 20 times magnifying glass to observe the surface with cracks, breaks, dangerous sections such as hook tails and threaded parts, and permanent deformation of hook tendons;
b. The wear of the section of the lanyard exceeds 10% of the original height, and the wear of the mandrel (pin) exceeds 5% of its diameter.
3.5 brake

3.5.1 Lifting mechanism brake
At least one supporting brake shall be installed for each independent driving device of the lifting mechanism.
The supporting brake should be normally closed. The brake must be installed on the load shaft rigidly connected to the transmission mechanism. The braking safety factor is:
Generally, the lifting mechanism is not less than 1.5;
The important lifting mechanism is not less than 1.75.
3.5.2 Luffing mechanism brake
The braking safety factor of the unbalanced luffing mechanism is the same as that of the hoisting mechanism.
The braking safety factor of the balanced luffing mechanism is not less than 1.25.
3.5.3 Slewing mechanism brake
The slewing machinery should adopt a steerable normally open brake, and its braking torque should be able to stop the slewing part of the crane in the most unfavorable working state and the maximum slewing radius. If a normally closed brake is used, the tangential acceleration of the head of the boom shall be the following recommended values:
a. It is recommended to take 0.1-0.3m/s2 for installation cranes;
b. 0.8-1.2m/s2 is recommended for loading and unloading cranes.
The one with the largest lift takes the smaller value.
In the non-working state, the brake should be released.
3.5.4 Use and inspection of brake
Before each shift, check: whether all components of the brake are operating normally; whether there is jamming; whether the brake block is attached to the brake wheel; whether the surface of the brake wheel is good and whether the adjusting nut is tight. Then lift the heavy object 150-200mm away from the ground, check the brake, and then lift it after confirming that it is normal. The adjustment and replacement of brake components shall be carried out in accordance with the following regulations:
a. The brake pad friction pad should be replaced when the wear exceeds 50% of the original pad thickness;
b. The brake wheel must be updated when the surface wear reaches 1.5-2mm (large diameter takes the larger value, and small diameter takes the smaller value);
c. The idle stroke of the lever system leading to the electromagnetic drop should not exceed 10% of the rated stroke of the electromagnet, if it exceeds this value, adjust or replace the pin;
d. The lever and spring should be replaced in time if there are cracks;
e. The contact area between the friction pad of the brake pad and the brake wheel should not be less than 75% of the area of the friction pad of the brake pad. The gap between the wheel and the pad should be uniform and the opening of the brake pad should not exceed 1mm. The opening of the belt should not exceed 1.5mm;
f. It is necessary to ensure that the brake has the necessary braking stroke: the braking stroke of the translation mechanism is about 1/5 of the operating speed, and the braking stroke of the lifting mechanism when it is fully loaded is 50-200mm;
g. The initial stroke of the newly installed electromagnet core should not exceed half of the rated stroke to prepare for adjustment after wear;
h. Check the oil level and oil quality regularly for hydraulic push rod brakes.
4 Safety protection device
4.1 Lifting load limiter
The tower crane lifting load limiter can be set according to user requirements.
The error of the lifting load limiter is not more than 5% of its rated value. When the lifting capacity reaches the rated value, there should be a light or sound alarm; when the lifting capacity exceeds 5% of the rated load, the power supply in the upward direction should be cut off, but the mechanism can move in the downward direction.
4.2 Lifting torque limiter
The tower crane should be equipped with a lifting moment limiter, the overall error of which is not more than 8% of its rated value. When the lifting torque exceeds 8% of its rated value, the torque limiter should cut off the power supply in the direction of ascending and increasing, but the mechanism can move in the direction of descending and decreasing.
4.3 Ultimate torque coupling

For the slewing mechanism with self-locking effect, a safety limit torque coupling should be installed. The setting of the ultimate torque coupling should comply with the relevant regulations of GB3811-83.
4.4 Wind direction anemometer
Tower cranes whose boom root hinge points are greater than 5m should be equipped with wind direction anemometers. When the wind speed is greater than the working limit wind speed, it should be able to issue an alarm to stop the operation. The instrument should be placed on the top of the crane to the highest limit position of the spreader without wind.
4.5 Stroke limit device
4.5.1 For the operating mechanism of the rail tower crane (or trolley), the travel limit switch block should be installed at the end of the stroke; the installation position of the limit switch block should fully consider the braking stroke of the crane (or trolley) to ensure that the crane (or trolley) (Or trolley) can automatically and safely stop when entering the end of the track or approaching other cranes on the same track.
4.5.2 The installation distance of the trolley travel limit stopper should not be greater than the cable length.
4.5.3 The tower crane should be equipped with a lifting height limiter at the limit position on the hook.
The lifting height limiter should be able to ensure that the distance between the hook frame and the fixed pulley after the power is cut off has at least 2 braking strokes, and not less than 200mm. Tower cranes with special requirements should be equipped with lower stoppers.
4.5.4 For the luffing jib tower crane, the amplitude limit switch and the prevention arm for the low and high positions of the boom should be set.
A device that rebounds and flips back.
4.6 Windproof rail clamp and anchor position
Tower cranes must be equipped with wind-proof rail clamps. The rail clamp should be able to ensure that the crane remains stationary under the action of non-working forces, and the design of the wind-proof rail clamp should meet the requirements of GB3811-83.

4.7 Buffer
Brackets should be installed at the end of the rail of the cart (trolley), and buffers must be installed on the crane. When the crane and the end of the track
When the bumpers collide, it must be ensured that the crane can stop smoothly without causing a violent impact. The design of the buffer should meet the requirements of GB3811-83.
4.8 For cranes traveling on rails, protective baffles must be installed on the wheel frames, and the gap between the baffles and the rails shall not exceed 5mm.
5 Manipulation
5.1 The design of the control system and their arrangement should avoid the possibility of misoperation. All control handles, buttons and pedals should be installed in convenient locations, with ample space for manipulation, so that the driver can see the lifting items without getting up from the seat.
5.2 Control handle or wheel controller. Generally choose the right hand to control the lifting and walking mechanism, and the left hand to control the rotation and small
Vehicle luffing or boom luffing mechanism.
If the handle is used for control, the movement direction of the crane mechanism should be consistent with the movement direction of the handle specified in Table 5.
Table 5 Handle movement direction
━━━━━━━━━━━━━━━━━━┯━━━━━━━━━━━━━━━
Machine, structure, transportation, movement, square, direction, hand, handle, transportation, movement, square, direction
────┬─────────────┼───────────────
│Lift, change inward│Toward the driver
Lifting, ││ (handle backward)
Luffing mechanism├─────────────┼────────────────
│Descent, downward change│Leave the driver
││(handle forward)
────┼─────────────┼───────────────
Swivel mechanism│Turn to the right│Handle to the right
│Turn left│Handle left
━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━━━━
When using a wheeled controller, the direction of movement of the mechanism should be consistent with the direction of handwheel movement specified in Table 6.
Table 6 Handwheel movement direction machine
━━━━━━━━━━━━━━━┯━━━━━━━━━━━━━━━━━━
Construction of transportation, movement, square, direction│hand, wheel, spin, turn, square, direction
───────────────┼─────────────────
Lifting, inward luffing│clockwise rotation
Turn right │
───────────────┼─────────────────
Downward, outward luffing│Rotate counterclockwise
Turn left │
━━━━━━━━━━━━━━━┷━━━━━━━━━━━━━━━━━━
5.3 There should be clear signs indicating the purpose and control direction on or near all the joysticks, handles, wheels and pedals.
5.4 The control should be light and flexible, and the control force and operating stroke should meet the following requirements:
a. Hand control force is not more than 100N, operating stroke is not more than 400mm;
b. The pedal control force is not more than 200N, and the pedal stroke is not more than 200mm.
5.5 Crane performance signs and operating procedures signs should be posted on obvious parts in the driver's cabin.
The signal control device should be set within the driver's field of vision while working.
6 Electrical
6.1 General provisions
6.1.1 The selection of electrical components should take into account the characteristics of large vibration, frequent electrical connection, and open-air operation during crane operation.
6.1.2 The electrical control equipment and components should be installed in the cabinet to prevent rain and dust.
The electrical cabinet power distribution box should have a door lock, and the door should have a schematic diagram or wiring diagram, operation instructions and warning signs, etc.
6.1.3 The crane structure must be well and reliably grounded. All the electrical equipment of the crane, the non-charged metal shell, the metal conduit, the metal sheath of the cable, and the low-voltage side end of the safety lighting transformer must be reliably grounded under normal conditions.
The grounding resistance is not more than 4Ω.
The selection and installation of the grounding device should meet the requirements for electrical safety.
6.1.4 The installation of electrical equipment must be firm. Earthquake-proof electrical appliances should have anti-vibration measures.
6.1.5 The electrical connection should be in good contact to prevent loosening. Wires and harnesses should be fixed with clips to prevent swinging.
6.2 Electrical control and manipulation
6.2.1 The resistor should be located in the electrical room or in a place that is not easily accessible to the staff, with protective measures.
6.2.2 When a wired remote control device is used, the ground control station and the cab control must have electrical interlocking. Ground
A dedicated grounding wire must be connected between the uncharged shell of the surface control device and the crane structure. The grounding resistance requirements shall comply with the provisions of 6.1.3 of this standard.
6.2.3 If it is operated by wireless remote control, it must be able to stop working automatically when it loses control.
6.2.4 When the linkage console is used for operation, the linkage console must have zero self-locking.
6.2.5 The control system should be equipped with necessary audio signals, which should act as an alarm at the work site.
6.2.6 The protective neutral wire and ground wire shall not be used as current-carrying circuits.
6.3 Electrical protection
6.3.1 The tower crane shall be provided with short-circuit and over-current protection, loss-of-voltage protection and zero-position protection in accordance with the requirements of GB3811-83.
6.3.2 The crane should generally be equipped with a main isolating switch with a fuse, but the lighting circuit of the crane should be bypassed by the main isolating switch and controlled separately, and the voltage shall not exceed 250V.
6.3.3 The crane must be equipped with an emergency switch that can quickly cut off the main power supply in an emergency, and install it in a place that is convenient for the driver to operate, and paint it with eye-catching colors.
6.3.4 The passage between the fixed part and the rotating part of the tower crane should be equipped with a safety switch or other device so that the driver can know that someone has entered the rotating part of the crane and pay attention.
6.3.5 Travel protection
6.3.5.1 The travel protection device shall comply with the provisions of 4.5 of this standard.
6.3.5.2 The limit switch should stop the movement of the mechanism safely and reliably, but the mechanism can move in the opposite direction. When the switch is out of contact, it should be able to automatically reset.
6.3.6 Lightning protection and electromagnetic wave induction protection
When the height of the tower crane boom hinge point is greater than 50m from the ground, lightning protection devices should be installed on the tower top and the boom head.

For tower cranes that work in places with strong electromagnetic wave induction, when high-voltage static electricity harmful to the human body is generated at the hook or structure, measures must be taken to prevent electromagnetic wave induction.
6.4 Lighting, signal
6.4.1 The crane driver's cab, electrical room, and passageway should be well illuminated.
6.4.2 The power supply voltage of fixed lighting devices should not exceed 220V. It is strictly forbidden to use metal structures as circuits for lighting circuits.
The power supply voltage of portable lighting devices should not exceed 36V, and it is prohibited to use autotransformers to supply power directly.
6.4.3 The tower crane with the tower top higher than 30m should be equipped with anti-collision red lights on the tower top and the boom head, and ensure that the power supply is not affected by shutdown.
6.4.4 Tower cranes that are towed as a whole shall be equipped with DC 24V width indicator lights, turn indicators, height indicators and brake lights during implementation.
6.4.5 For tower cranes that work at night, spotlights facing the working surface should be installed on the tower body or other parts.
6.4.6 The opening and closing status of the crane's main power supply should have an obvious indication signal in the driver's cabin.
6.4.7 The indication signal or audible alarm signal of the safety protection device should be set up where the driver's eyesight or hearing can reach.
6.5 Wire and its laying
6.5.1 The selection and laying of power conductors should comply with the requirements of GB3811-83.
6.5.2 The power supply cable of the crane should be equipped with a special core wire or a protective grounding neutral wire made of a metal sheath.
6.5.3 The lighting and heating lines should be laid separately.
6.5.4 A junction box should be set at the connection and branch point of the wire. The outdoor junction box should be waterproof, and the wire hole should be sheathed.
6.5.5 Both ends of the wire should have permanent marks consistent with the schematic diagram and wires for connection

6.5.6 The wiring steel pipe should be clear of burrs, the edges and corners of the pipe mouth should be rounded, and be treated with anti-corrosion treatment.
6.5.7 The bending radius of fixedly laid cables shall not be less than 5 times the outer diameter of the cable; the bending radius of movable cables shall not be less than 8 times the outer diameter of the cable.
6.6 Cable drum
The power supply cable drum of the crane traveling on the track should have a tensioning device to prevent the cable from being disturbed or falling on the track.
The connection between the cable and the reel must be secured to protect the electrical contacts from being pulled.
6.7 Collector
6.7.1 The collector slip ring shall meet the requirements of the corresponding voltage level and current capacity. Each slip ring has at least one pair of carbon brushes;
The contact area between the carbon brush and the ring should not be less than 80%, and the contact should be stable.
6.7.2 The insulation resistance between the slip ring and the slip ring is not less than 1MΩ. The minimum distance between the slip rings is not less than 6mm, and has undergone a pressure test without breakdown or flashover.
7 Hydraulic system 7.1 The hydraulic system should have safety devices to prevent overload and hydraulic shock. The adjustment pressure of the safety relief valve shall not be greater than 110% of the normal working pressure of the system, and the maximum adjustment pressure of the relief valve shall not exceed the rated working pressure of the hydraulic pump.
7.2 The jacking fluid hydraulic cylinder must have a reliable balance valve or hydraulic lock. The balance valve or hydraulic lock and the hydraulic cylinder must not be connected by hoses.
7.3 The system should be equipped with other devices to prevent oil pollution, and the accuracy should be in line with the hydraulic system element
Requirements. The cleanliness of the system should comply with the relevant regulations on the cleanliness of the hydraulic system.
7.4 When designing hydraulic cylinders, it must