GB/T 19924-2021Mobile cranes - Determination of stability (English PDF)

4.1 General

The calculation should verify that the crane is stable under the following conditions.

a) The criteria specified in Table 1;

b) The criteria specified in Table 2;

c) The criteria specified in Table 3;

d) Backflip stability (see 4.3);

e) Stability under non-working wind loads (see 4.4).

4.2 Stability criterion

4.2.1 See Table 1, Table 2 and Table 3 for stability criteria.

4.2.2 Based on the criteria specified in Table 1, Table 2 and Table 3, consideration should be given to the amount of crane stability determined when the minimum wind speed is 8.3m/s.

Set the weight. In special cases, the manufacturer should clearly indicate the maximum wind speed used in the stability calculation.

Table 1 Stability calculation under applied load

4.3 Back roll stability (with or without main arm)

4.3.1 General

The crane is under the following conditions, and the balance weight should be limited to the mass distribution position given below to ensure that the crane has a reasonable stability

Safety factor.

--- Placed on a solid, level supporting surface (the inclination is not more than 1%);

--- Equipped with the specified shortest main boom, and is at the maximum elevation angle of the boom;

---The hook, hook pulley block or other spreaders are placed on the ground;

---Without main arm;

---The outriggers leave the supporting surface and are calculated according to the crane supported on the wheels (tires);

--- Equipped with the specified longest main boom or main boom plus jib, at the maximum elevation angle allowed by the combined boom, and assumed to withstand the most unfavorable direction

Working wind load.

The principle of crane mass distribution is. under each balance weight condition, it should meet the most unstable crane rotation allowed by the manufacturer

position.

4.3.2 Crawler crane---the shortest main boom and the minimum working range

4.3.2.1 Crawler cranes---general

The total load on the tipping line of the side or end of the chassis supporting the smallest load shall not be less than 15% of the total gravity of the crane.

For a crawler crane equipped with a retractable crawler device, if the crawler device cannot meet the above requirements when the crawler device is retracted, the manufacturer shall

Drivers are provided with conspicuous warning information on board.

4.3.2.2 Crawler crane-without main boom

The total load on the tipping line of the side or end of the chassis supporting the smallest load shall not be less than 5% of the total gravity of the crane.

For a crawler crane equipped with a retractable crawler device, if the crawler device cannot meet the above requirements when the crawler device is retracted, the manufacturer shall

Drivers are provided with conspicuous warning information on board.

4.3.3 Wheeled cranes---the shortest main boom and the minimum working range

4.3.3.1 Wheeled cranes---general

When the longitudinal axis of the upper structure of the crane is 90° with the longitudinal axis of the chassis, the wheel (tire) or outrigger under the crane boom

The total load on the crane should not be less than 15% of the total gravity of the crane.

When the longitudinal axis of the slewing mechanism on the crane coincides with the longitudinal axis of the chassis, the light-load end of the chassis is within the working area specified by the manufacturer

The total load on wheels (tyres) or legs shall not be less than 15% of the total gravity of the crane. In the non-working area, it should not be less than the total crane

10% of mass gravity.

Unless eye-catching warning information is provided for the operator on the crane, the relevant regulations on the wheels (tires) of the crane shall be met.

In order to ensure sufficient backflip stability, the warning message should indicate the requirements for the extended state of the outriggers.

4.3.3.2 Wheeled crane-without main boom

When the longitudinal axis of the upper structure of the crane is 90° with the longitudinal axis of the chassis, the wheel (tire) on the side of the chassis that bears the smaller load

Or the total load on the outriggers should not be less than 5% of the total gravity of the crane.

When the longitudinal axis of the upper structure of the crane revolves coincides with the longitudinal axis of the chassis, the chassis is lightly loaded in the working area specified by the manufacturer

The total load on the end wheel (tyre) or outrigger shall not be less than 5% of the total gravity of the crane. In the non-working area, it should not be smaller than the crane

5% of the total mass gravity. Unless eye-catching warning information is provided for the operator on the crane, it should be satisfied that the crane is on the wheels (wheels).

Tires). In order to ensure sufficient backflip stability, the warning message should indicate the requirements for the extended state of the outriggers.

4.4 Stability under non-operating wind loads

The manufacturer shall specify the special precautions to be taken when the crane is not working, and the working limit of the wind load (wind load

For regulations, see ISO 4302).

4.5 Determination of stability

4.5.1 Under the load conditions specified in Table 1 and Table 2, the value of P shall be such that the crane tipping moment is less than the stable moment in any case.

4.5.2 The stability should be calculated according to the most unfavorable position of the crane. In addition, all loads, balance weights, and accessories that affect the stability of the crane

The most unfavorable value and position should be taken into consideration.

4.5.3 Refer to Appendix A for the tipping lines of different types of cranes and the tipping lines relative to the calculated stable moment. The tipping line in Appendix A is just

It is indicated that the actual tipping line should be determined according to the specific design situation.

4.5.4 Crane tipping angle. When calculating the crane turning to the most unstable direction, the tipping angle of different configurations and different rated lifting weights should be calculated.

Greater than or equal to the minimum value given in Table 3.For tilting angle alpha, refer to Figure B.1 to Figure B.6 of Appendix B. When calculating the rear tipping angle, the crane should be installed

With the main (auxiliary) boom, the hook should be placed on the ground.