Foreword
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This document is developed in accordance with the rules given in GB/T 1.1-2020 Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents.
This document replaces GB/T 26777-2011 Semitrailer landing gears. In addition to structural adjustments and editorial changes, the following main technical changes have been made with respect to GB/T 26777-2011:
a) The clause "Terms and definitions" is added (see Clause 3 hereof);
b) The drive mode is added (see 4.2 hereof);
c) The base type is modified (see 4.3 hereof; 3.2 of Edition 2011);
d) The model designation is modified (4.4 hereof; 3.3 of Edition 2011);
e) The lateral load is deleted from the basic parameters (see 3.4.2 of Edition 2011);
f) The requirements for paint coating are added (see 5.1.1 hereof);
g) The requirement that the landing gears shall have two-speed gear transmission device is modified (see 5.1.2 hereof; 4.1 of Edition 2011);
h) The requirement that the landing gears shall be equipped with a floor-to-floor smooth moving gasket or base is deleted (see 4.2 of Edition 2011);
i) The requirement that the landing gears shall be equipped with lubrication device is deleted (see 4.7 of Edition 2011);
j) The welding requirements are modified (see 5.1.7 hereof; 4.10 of Edition 2011);
k) The requirements for the rated working voltage of electro-mechanical and electro-hydraulic landing gears are added (see 5.1.8 hereof);
l) The hydraulic failure protection requirements for manual hydraulic and electro-hydraulic landing gears are added (see 5.1.9 hereof);
m) The requirements for the hydraulic system of the landing gears are added (see 5.1.10 hereof);
n) The handle force of the landing gears is modified into torque (see 5.2.1 hereof; 4.13 of Edition 2011);
o) The requirements for the interchangeability dimensions are modified (see 5.2.2 hereof; 4.9 of Edition 2011);
p) The requirements for lifting load are added (see 5.3.1 hereof);
q) The low gear lift stroke requirements for landing gears are modified (see 5.3.2 hereof; 4.12 of Edition 2011);
r) The static load capacity requirements of the landing gears are modified (see 5.3.3 hereof; 5.3.1 of Edition 2011);
s) The transverse strength requirement of the landing gears is modified and the longitudinal strength requirement of the landing gears is added (see 5.3.4 hereof; 4.11 of Edition 2011);
t) The requirements for vertical strength of landing gears are added (see 5.3.5 hereof);
u) The requirements for the no-load operating capacity of the landing gears are added (see 5.3.6);
v) The reliability requirements are modified (see 5.3.7 hereof; 4.14 of Edition 2011);
w) The stability requirements of the landing gears are added (see 5.3.8 hereof);
x) The dynamic bearing capacity of the landing gears are added (see 5.3.9 hereof);
y) The impact resistance requirements of the landing gears are added (see 5.3.10 hereof);
z) The requirements for test equipment are deleted (see 5.1 of Edition 2011);
aa) The test load requirement is deleted (see 5.2 of Edition 2011);
ab) The test requirements are added (see 6.1 hereof);
ac) The test method of lifting capability is modified (see 6.2 hereof; 5.3.2 of Edition 2011);
ad) The test method of lifting stroke is added (see 6.3 hereof);
ae) The test method of bearing capacity is modified (see 6.4 hereof; 5.3.1 of Edition 2011);
af) The longitudinal and transverse strength test methods are modified (see 6.5 hereof; 5.3.3 of Edition 2011);
ag) The test method of vertical strength is added (see 6.6 hereof);
ah) The test method of no-load operating is added (see 6.7 hereof);
ai) The test method of reliability is modified (see 6.8 hereof; 5.3.4 of Edition 2011);
aj) The stability test method of the landing gears in the loading state is added (see 6.9 hereof);
ak) The dynamic load capacity test method of the landing gears in the loading state is added (see 6.10 hereof);
al) The impact test method is added (see 6.11 hereof);
am) The inspection classification is added and the end-of-manufacturing inspection items and type inspection items are modified (see 7.1 hereof; 6.1.2 and 6.2.2 of Edition 2011);
an) The type inspection sampling requirements are modified (see 7.2.1 hereof; 6.2.1 of Edition 2011);
ao) The contents on the nameplate of product are modified (see 8.1 hereof; 7.1 of Edition 2011).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This document was jointly proposed by the Ministry of Industry and Information Technology of the People's Republic of China and the Ministry of Transport of the People's Republic of China.
This document is under the jurisdiction of the National Technical Committee of Auto Standardization (SAC/TC 114).
This document was firstly issued in 2011, and this edition is the first revision.
Trailer landing gears
1 Scope
This document specifies the types and basic parameters, technical requirements, test methods, inspection rules, markings, and product manuals of trailer landing gears.
This document is applicable to landing gears installed and used on freight trailers (except centre-axle transport trailers).
2 Normative references
The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB/T 3766 Hydraulic fluid power - General rules and safety requirements for systems and their components
JB/T 5000.3 Heavy mechanical general technical specification - Part 3: Welding parts
QC/T 484-1999 Automobile paint coating
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
trailer landing gears
device mounted on a trailer to support the trailer and keep it stable when the towing vehicle is separated from the trailer
Note: It generally includes landing leg, handle, connecting rod, fixing frame, diagonal brace, etc.
3.2
landing leg
load-bearing assembly of the landing gears
Note: It is generally divided into left landing legs and right landing legs, mainly including outer leg, inner leg, base, driving mechanism and transmission mechanism.
3.3
lifting load
working load of a pair of landing gears during operation
3.4
static load
maximum allowable static load of a pair of landing gears
4 Type and basic parameters
4.1 Structural type
The landing gears are divided into the following two types according to structural types:
a) Single-acting type: the stroke of the left landing legs and the right landing legs is adjusted independently respectively, coded as D;
b) Coordinated type: the stroke of the left landing legs and the right landing legs is synchronously adjusted on one side, coded as L.
4.2 Drive type
The landing gears are divided into the following four types according to drive types:
a) Manual mechanical type: the mechanical transmission device is driven manually to realize the lifting of the trailer, coded as SJ;
b) Electro-mechanical type: the motor drives the mechanical transmission device to realize the lifting of the trailer, coded as DJ;
c) Manual hydraulic type: the hydraulic system is driven manually to realize the lifting of the trailer, coded as SY;
d) Electro-hydraulic type: the motor drives the hydraulic system to realize the lifting of the trailer, coded as DY.
4.3 Base type
The base of the landing gears is divided into Type A, Type G, Type R, Type S and Type T according to its structural type, as shown in Figure 1.
a) Type A b) Type G c) Type R d) Type S e) Type T
Note 1: Type A: The base is of fan-shaped curved surface structure, which is connected with the inner leg through a pin shaft, and the fan-shaped base can rotate around the pin shaft.
Note 2: Type G: The base is of flat plate structure, which is directly fixed and welded with the inner leg.
Note 3: Type R: The base includes two casters, which are connected with the inner leg through a pin shaft, and the casters can rotate around the pin shaft.
Note 4: Type S: The base is of flat plate structure, and a sector plate is fixed at the bottom. The sector plate and the flat plate base are connected with the inner leg through a pin shaft, and the flat plate base can rotate around the pin shaft.
Note 5: Type T: The base is of flat plate structure, without fan-shaped plate, which is connected with the inner leg through a pin shaft, and the flat plate base can rotate around the pin shaft.
Figure 1 Schematic diagram of base structure of landing gears
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Type and basic parameters
5 Technical requirements
6 Test methods
7 Inspection rules
8 Marking and product instructions
Bibliography
