GB/T 26777-2023Trailer landing gears (English PDF)

3.1 Trailer landing gears

A device installed on a trailer to support the trailer and maintain it stable when the towing vehicle is detached from the trailer.

NOTE: it generally includes landing legs, handles, connecting rods, fixed frames and diagonal braces, etc.

3.2 Landing leg

An assembly of load-bearing components of the landing gears.

NOTE: it is generally divided into left landing leg and right landing leg, and mainly includes outer leg, inner leg, base, driving mechanism and transmission mechanism, etc.

5.2 Requirements for Interchangeability and Main Parameters

5.2.1 The adjustable stroke and main technical parameters of the landing gears shall comply with the relevant stipulations of Table 1.

5.3 Performance Requirements

5.3.1 The landing gears shall be tested for lifting capacity in accordance with the stipulations of 6.2. The lifting load and corresponding torque shall comply with the stipulations of Table 1.

5.3.2 The manual mechanical type and electromechanical type of landing gears shall be tested for lifting stroke in accordance with the stipulations of 6.3. The lifting stroke of the power input spindle for one rotation shall not be less than 0.6 mm.

5.3.3 After the landing gears are subject to the load-bearing capacity test in accordance with the stipulations of 6.4, there shall be no structural damage and abnormal wear, etc. (except for wearing parts), and they shall still be able to normally operate. The hydraulic system of the hydraulic type landing gears shall not leak, and the sinkage shall not be greater than 5 mm.

5.3.4 After the landing gears are subject to the longitudinal and transverse strength test in accordance with the stipulations of 6.5, they shall be able to normally expand and retract under the no-load condition. During expansion and retraction, the torque required by the mechanical landing gears shall be less than 67 N·m, and the hydraulic system of the hydraulic type landing gears shall not leak.

5.3.5 After the landing gears are subject to the vertical strength test in accordance with the stipulations of 6.6, they shall be able to normally expand and retract under the no-load condition. During expansion and retraction, the torque required by the mechanical landing gears shall be less than 67 N·m, and the hydraulic system of the hydraulic type landing gears shall not leak.

5.3.6 After the landing gears are subject to the no-load operation test in accordance with the stipulations of 6.7, there shall be no structural damage and abnormal wear, etc., and they shall still be able to normally operate.

5.3.7 After the landing gears are subject to the reliability test in accordance with the stipulations of 6.8, there shall be no structural damage and abnormal wear, etc., and they shall still be able to normally operate.

5.3.8 After the landing gears are subject to the stability test in accordance with the stipulations of 6.9, there shall be no structural damage, permanent deformation and abnormal wear, etc., and they shall still be able to normally operate.

5.3.9 After the landing gears used for multimodal trailers are subject to 1,000 times of dynamic load-bearing test in accordance with the stipulations of 6.10, there shall be no structural damage, permanent deformation and abnormal wear, etc., and they shall still be able to normally operate.

5.3.10 After the landing gears used for multimodal trailers are subject to the impact test in accordance with the stipulations of 6.11, there shall be no structural damage and abnormal wear, etc., and they shall still be able to normally operate.

6.1 Test Requirements

The installation of auxiliary connectors and landing gears used for the tests shall comply with the manufacturer's design requirements. During the tests, necessary maintenance can be performed in accordance with the manufacturer's regulations.

6.2 Lifting Capacity Test

6.2.1 In accordance with the method recommended by the manufacturer, vertically install the landing gears on a special-purpose testing machine, fix and tightly lock it.

6.2.2 Operate the landing gears to extend the inner leg by 370 mm (if the stroke is less than 395 mm, extend the maximum stroke, and then, retract by 25 mm), along the F1 direction shown in Figure 4, load it to the lifting load.

6.2.3 Use the low-speed gear to operate the mechanical type of landing gears, so that the inner leg extends by 25 mm at a constant speed. Measure and record the torque for no less than 10 times and calculate the average value.

6.2.4 Operate the hydraulic type of landing gears, so that the inner leg extends by 25 mm at a constant speed. Measure and record the hydraulic system pressure for no less than 10 times, and the average value shall not be greater than the specified rated working pressure. […]