JB/T 8906-2014 PDF English
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JB/T 8906-2014: PDF in English (JBT 8906-2014) JB/T 8906-2014
JB
MECHANICAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 53.020.20
J 80
Filing No.: 45923-2014
Replacing JB/T 8906-1999
Cantilever crane
ISSUED ON: MAY 06, 2014
IMPLEMENTED ON: OCTOBER 01, 2014
Issued by: Ministry of Industry and Information Technology.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 8
4 Types and basic parameters ... 10
5 Technical requirements ... 14
6 Test methods ... 26
7 Inspection rules ... 29
8 Marking, packaging, transportation, storage ... 31
Cantilever crane
1 Scope
This standard specifies the terms and definitions, types and basic parameters, technical
requirements, test methods, inspection rules and markings, packaging, transportation,
storage of cantilever cranes defined in 3.1.3.9 of GB/T 6974.1-2008.
This standard applies to cantilever cranes, that work in general working environments
and use electric hoists and (or) self-propelled or towed electric trolleys as lifting
mechanisms (hereinafter referred to as cranes). For other types of cantilever cranes, it
can also be used as a reference.
This standard does not apply to cranes under the following conditions:
- Pitching and luffing;
- Nuclear radiation environment, toxic gas environment;
- Lifting molten metal, flammable, explosive items.
2 Normative references
The following documents are essential to the application of this document. For the dated
documents, only the versions with the dates indicated are applicable to this document;
for the undated documents, only the latest version (including all the amendments) is
applicable to this standard.
GB 755-2008 Rotating electrical machines - Rating and performance
GB/T 1184-1996 Geometrical tolerancing - Geometrical tolerance for features
without individual tolerance indications
GB/T 1228 High strength bolts with large hexagon head for steel structures
GB/T 1229 High strength large hexagon nuts for steel structures
GB/T 1230 High strength plain washers for steel structures
GB/T 1231 Specifications of high strength bolts with large hexagon head, large
hexagon nuts, plain washers for steel structures
GB 2893 Safety colors
4 Ω (the user is responsible).
5.1.4 The altitude of the crane installation and use site shall generally not exceed 1000
m; when it exceeds 1000 m, the output power of the motor shall be corrected according
to the requirements of 7.7.2.4 in GB/T 3811-2008; when it exceeds 2000 m, it shall be
in accordance with the requirements of Appendix B in GB 14048.1-2012.
5.1.5 Climate conditions when the crane is working indoors:
a) The ambient temperature does not exceed 40 °C; the average temperature within
24 h does not exceed 35 °C;
b) The ambient temperature is not lower than -5 °C;
c) The relative humidity at 40 °C does not exceed 50%.
5.1.6 Climate conditions when the crane is working outdoors:
a) The ambient temperature does not exceed 40 °C; the average temperature within
24 hours does not exceed 35 °C;
b) The ambient temperature is not lower than -20 °C;
c) When the ambient temperature is at the highest temperature of 40 °C, the relative
humidity shall not exceed 50%; higher humidity can be allowed at lower
temperatures (such as 90% at 20 °C); the harmful effects of accidental
condensation shall be avoided, by properly designing electrical equipment or
using appropriate additional facilities (such as heaters, air conditioners, drainage
holes, etc.) in necessary places;
d) The working wind pressure shall not be greater than 150 Pa inland (equivalent to
level 5 wind), or 250 Pa along the coast (equivalent to level 6 wind);
e) The maximum wind pressure in non-working state is generally 800 Pa (equivalent
to level 10 wind), which can also be agreed upon separately.
5.1.7 The operating conditions of the motor shall comply with the provisions of Chapter
6 and Chapter 7 of GB 755-2008.
5.1.8 The normal use, installation, operation conditions of electrical appliances shall
comply with the provisions of Chapter 6 of GB 14048.1-2012.
Note: When exceeding the above range, the user shall negotiate with the manufacturer to
resolve.
5.2 Basic requirements
5.2.1 The design and manufacture of cranes shall comply with the relevant provisions
of GB/T 3811, GB 6067.1 and this standard.
5.2.2 The electronic control equipment of cranes shall comply with the provisions of
GB 5226.2 and this standard.
5.2.3 The selection, layout, wire laying, auxiliary facilities of components involved in
the electrical transmission system and electrical control system shall comply with the
provisions of Chapter 7 of GB/T 3811-2008.
5.3 Performance in use
5.3.1 The lifting capacity of the crane shall reach the rated lifting capacity. For a crane
with a fixed sling, its rated lifting capacity refers to the maximum mass of the weight
hanging on the fixed sling of the crane; for a crane with a detachable sling, its rated
lifting capacity refers to the sum of the mass of the detachable sling and the maximum
mass of the weight hanging on the detachable sling of the crane.
5.3.2 Parameters related to the use of the crane shall comply with 4.2 and the
requirements of the user in the order contract.
5.3.3 During the static load test, the crane shall be able to withstand a test load of 1.25
times the rated lifting capacity. After the test, a visual inspection shall be carried out.
The stressed metal structural parts shall be free of cracks and permanent deformation,
paint peeling or damage that affects the performance and safety of the crane; the joints
shall not be loose or damaged.
5.3.4 During the dynamic load test, the crane shall be able to withstand a test load of
1.1 times the rated lifting capacity. During the test, each component shall be able to
complete its functional test; the safety devices such as brakes shall act sensitively and
reliably. After the test, a visual inspection is carried out. All mechanisms and structural
parts shall be free of damage; all joints shall be free of looseness or damage.
5.3.5 The vertical static deflection of the crane shall meet the following requirements:
a) The hoisting trolley running on the boom will not lose control during normal
operation;
b) The boom shall not rotate on its own.
5.3.6 The static rigidity for pillar jib cranes, wall jib cranes, wall-pillar fixed cranes is
recommended as follows: the vertical static deflection caused by the rated lifting weight
and the deadweight load of the hoisting trolley (hoist) at the effective radius shall not
exceed the provisions of Table 4.
5.4.3.1 Both the crane operating mechanism and the trolley operating mechanism shall
be equipped with travel switches, stops, track sweeping plates, buffers. The operating
of electric hoist may not be equipped with travel switches and track sweeping plates.
5.4.3.2 When there are two cranes on the same track, anti-collision devices shall be
installed between them. If the distance between them needs to be strictly controlled, a
fixed-distance device should be set.
5.4.4 Slewing mechanism
5.4.4.1 When necessary, a slewing locking device shall be installed.
5.4.4.2 When it is necessary to limit the slewing range, a slewing angle limiter shall be
installed.
5.4.4.3 Brakes shall be provided; the selection of brake safety factors shall comply with
the provisions of 6.1.3.5 in GB/T 3811-2008.
5.4.4.4 When hydraulic or mechanical brakes are used, an interlocking device that can
cut off the synchronous electrical brake shall be provided. When a mechanical or
hydraulic electric locking normally closed brake is not provided, a mechanical locking
device (such as a pin or other embedded device) shall be used to lock the slewing motion.
5.4.5 Passages, platforms, railings, ladders
The passages, platforms, railings, ladders of double-beam cranes shall comply with the
provisions of 3.6 ~ 3.8 in GB 6067.1-2010.
5.4.6 Electrical protection and interlocking protection
5.4.6.1 Electrical protection
The electrical protection of the crane shall comply with the provisions of 8.1 ~ 8.5 in
GB 6067.1-2010.
5.4.6.2 Interlocking protection
The crane shall have the following interlocking protection:
a) Passage doors involving personal safety shall be equipped with door switches
(electrical interlocking protection devices). When any door is opened, the power
supply of the corresponding mechanism of the crane shall be disconnected;
b) When the crane requires multi-point operation, the operating points shall be
interlocked with each other, to ensure that only one operating point is in working
state at any time; meanwhile each operating point shall be equipped with an
emergency power-off device.
5.4.6.3 Emergency stop switch
The crane shall be equipped with an emergency stop switch, in accordance with the
requirements of 6.2.4 in GB 6067.1-2010.
5.4.7 Insulation and grounding
5.4.7.1 The insulation resistance of each circuit in the crane's electronic control
equipment shall not be less than 1.0 MΩ in a normal environment.
5.4.7.2 The grounding resistance of the crane shall not be greater than 4 Ω. The
grounding of the crane to the earth shall be carried out by a grounding slider (or a
grounding core), or other reliable grounding methods. The metal casing of all electronic
control equipment on the crane must be effectively grounded.
5.4.8 Protection, warning, alarm
5.4.8.1 If there are exposed rotating parts on the crane that may injure people, such as
open gears, couplings, transmission shafts, it shall provide protective shields. However,
if it is not possible to install protective shields, safety warning signs or warning sign
plates shall be installed.
5.4.8.2 Clearly visible text safety warning signs shall be set at appropriate locations or
working areas of the crane, such as "No one is allowed to stand under the hoisted
objects". Safety signs and hazard graphic symbols shall be set at dangerous parts of the
crane. Safety signs and hazard graphic symbols shall comply with the provisions of GB
2893 and GB 15052.
5.4.8.3 The crane shall have a signal indicating the main power supply disconnection
and connection status; a fault signal or alarm signal shall be set when necessary.
5.4.9 Noise
The noise generated by the crane during operation shall not be greater than 85 dB (A)
at the driver's operating position, where there is no other external sound interference.
5.5 Main components
5.5.1 Electric hoist
The selection of wire rope electric hoists shall comply with the requirements of JB/T
9008.1.
The selection of chain electric hoists shall comply with the requirements of JB/T 5317.
5.5.2 Wire rope
When winding multiple layers, it shall use steel core wire ropes that comply with GB
8918. For cranes with higher requirements for wire rope toughness, fiber core wire
ropes that comply with GB 8918 shall be used first. In other cases, wire ropes with
performance not lower than that of GB/T 20118 should be used.
5.5.3 Motors
Preferably, motors that comply with the following standards shall be used: JB/T 7076,
JB/T 7077, JB/T 7078, JB/T 7842, JB/T 8955, JB/T 10104, JB/T 10105, JB/T 10360.
Variable frequency motors that comply with GB/T 21972.1 or multi-speed motors that
comply with GB/T 21971 can also be used as needed.
5.5.4 Brakes
Preferably, brakes that comply with the following standards shall be used: JB/T 6406,
JB/T 7019, JB/T 7020, JB/T 7685.
5.5.5 Couplings
It is not recommended to use couplings that may cause the brake wheel (disc) to float.
5.5.6 Reducer and gear transmission
Preferably, reducers that meet the following standards shall be selected: JB/T 8905.1,
JB/T 8905.2, JB/T 8905.3, JB/T 8905.4, JB/T 9003, JB/T 10816, JB/T 10817. When
other reducers are selected, the accuracy of hardened gear pairs shall not be lower than
level 6 specified in GB/T 10095-2008; the accuracy of medium-hardened gear pairs
shall not be lower than level 8-8-7. Open gear pairs shall be heat-treated; medium-
hardened or hardened gear pairs should be used for meshing; the accuracy of gear pairs
shall not be lower than level 9 in GB/T 10095-2008.
5.5.7 Sheaves and drums
Sheaves that comply with GB/T 27546 and drums that comply with JB/T 9006 shall be
used preferentially. The structural type of welding drums is generally short-axis type; it
can be connected to the reducer with a drum coupling.
5.5.8 Hooks
Hooks that comply with GB/T 10051.1 ~ GB/T 10051.12 shall be used preferentially.
5.5.9 Wheels
Wheels that comply with JB/T 6392 shall be used preferentially.
5.5.10 Buffers
Buffers that comply with JB/T 7017, JB/T 8110.1, JB/T 8110.2, JB/T 10833 shall be
used preferentially.
5.8 Electric control equipment
5.8.1 The technical performance of electric control equipment, limiters and other
electrical components used in electric hoists shall comply with the corresponding
requirements of JB/T 9008.1 or JB/T 5317.
5.8.2 The degree of protection of the electric control equipment shall be adapted to the
working environment of the crane. For cranes used indoors, the electrical equipment
installed on the pillar or cantilever (jib) shall have no exposed live parts; the minimum
degree of protection shall be IP30 in GB 4208-2008. For cranes used outdoors, when
the control cabinet on the cantilever (jib) is installed in an unsheltered place, the degree
of protection of enclosure shall not be lower than IP54 in GB 4208-2008; when installed
and used in a sheltered place, the degree of protection of enclosure may be reduced, but
it shall meet the protection requirements.
5.8.3 The crane and the trolley (or electric hoist) can be fed with slider busbars or cables.
When the crane uses angle steel (copper) slider busbars, protective devices shall be
provided. It is recommended that the slider busbars use a slider transmission device that
complies with JB/T 6391.1. Where the user has special requirements, it may also use
copper wire, profile steel or other new feeding devices.
5.8.4 The steel wire or wire rope used for erecting mobile cables shall be galvanized;
the sheave and sheave tracks shall be rust-free, painted or galvanized.
5.8.5 The wire protection tube shall be firmly fixed on the cantilever (jib); the pipe
opening shall be equipped with a wire protection nozzle; the wires laid in the wire
protection tube shall not have joints.
5.8.6 All wires laid in the wire protection tube shall be copper core multi-strand wires.
The cross-sectional area of the main circuit is selected according to the controlled power
and shall not be less than 1.5 mm2.
5.8.7 When the crane cantilever is designed to rotate without limit, a slip ring device
shall be installed, to ensure that the power supply is not restricted when the cantilever
rotates. When the crane design only allows the cantilever to rotate within a limited range,
a slip ring device is not required, but a block shall be installed to prevent it from
exceeding the limited range.
5.9 Painting
5.9.1 Steel surface treatment before painting
Important structural parts such as crane pillars, cantilever (jib) shall be shot blasted to
remove rust and reach level in GB/T 8923; the other components shall reach
Sa2 level or St2 level (manual rust removal).
5.9.2 Paint quality
5.9.2.1 The crane topcoat shall be uniform, fine, bright, complete, consistent in color;
it shall not have defects such as roughness, holiday, paint mismatch, wrinkles, pinholes,
severe sagging.
5.9.2.2 Recommended total paint film thickness: 75 μm ~ 105 μm for indoor cranes: 80
μm ~ 120 μm for outdoor cranes. Depending on the needs of the crane working
environment, it can also be agreed upon by the supplier and the buyer.
5.9.2.3 The paint film adhesion shall meet the first-level quality requirements specified
in GB/T 9286.
6 Test methods
6.1 General
Crane tests shall follow the specifications and procedures specified in GB/T 5905.
6.2 Visual inspection
The visual inspection shall include whether the specifications and (or) status of all
important components meet the requirements, such as:
- All mechanisms, electrical and hydraulic equipment, safety devices, brakes,
controllers, lighting and signal systems;
- Metal structures of the crane and their connections, ladders, passages, walkways;
- All protective devices;
- Hooks or other picking devices and connections;
- Wire ropes and their fasteners;
- Pulley blocks and their shafts and fastening parts.
During the inspection, it is not necessary to disassemble any components except for the
covers that need to be opened for normal maintenance and inspection (such as limit
switch covers).
The inspection procedure shall also include checking whether the acceptance
documents specified in GB/T 17908 have been submitted and passed the review.
6.3 No-load test
Before turning on the power supply, check whether the lubricant is applied to each
lubrication part as required. Turn on the power supply. Start each mechanism. Make the
trolley (or electric hoist) run back and forth along the full length of the jib once, to
check whether there is any jamming. Start and check other mechanisms, to see if they
are operating normally, whether the control system and safety devices meet the
requirements and are sensitive and accurate, meanwhile check the lifting height and the
left and right limit positions of the hook.
6.4 Rated load test
After 2 ~ 3 gradual loadings until the rated lifting weight, perform action tests and tests
in all directions, to verify whether the lifting speed, braking slippage, rotation speed,
running speed of the crane meet the requirements of the design drawings and this
standard.
6.5 Lifting speed
When the lifting distance exceeds 0.5 m, use a stopwatch to measure the distance lifted
within 10 s, or take a fixed distance and measure the required time. Calculate the lifting
speed by calculation. Make four measurements in a row. Take the average value.
6.6 Determine the running speed of the hoisting trolley (or electric hoist) and the
running speed of the crane
When making measurement, mark two points on the track that are not less than 2 m
apart. When the hoisting trolley (electric hoist) or crane runs normally to the mark, start
timekeeping; when it runs to another mark, stop the timekeeping. Repeat four times.
Calculate the speed respectively. Take the average value.
6.7 Braking downslide
Use a steel rope with a diameter of 1 mm, to tie a small weight at one end; connect the
other end to a fixed micro switch (contact normally closed). The normally closed
contact is connected to the descending circuit controlled by a contactor. The weight
shall be sufficient to actuate the switch and cut off the descending circuit. When
measuring, the small weight is placed on the load (weight). When the load descends to
a certain position, the small weight is separated from the load. At this time, the
descending circuit is immediately cut off, meanwhile the load immediately begins to
slide down. The vertical distance between the small weight and the load is measured,
which is the downslide. Make three measurements in a row. Take the average value.
6.8 Crane noise
6.8.1 Noise of pillar jib cranes, wall jib cranes, wall-pillar fixed jib cranes
In a non-enclosed workshop, lift the rated lifting capacity at the effective radius. Use a
sound level meter at 6 m away from the trolley (or electric hoist), to make four
measurements according to the A-level reading (twice each for lifting and lowering).
mechanisms and brakes of the crane.
The dynamic load test of each mechanism of the crane shall be carried out separately
first; the test of combined action shall be carried out when specified. When conducting
the test of combined action, no more than two mechanisms shall be operated at the same
time.
The lifting mechanism is loaded at 1.1 times the rated lifting weight. During the test,
each action shall be started and braked repeatedly within its travel range. When the
suspended test load is started in the air, the test load shall not have reverse action.
During the test, the operation interval shall be reserved according to the continuous
power-on rate of the crane's motor; the control shall be carried out according to the
operating procedures. Attention shall be paid to limiting the acceleration, deceleration,
and speed within the normal working range of the crane.
After the test, visually check whether the components of each mechanism or structure
are damaged; check whether the joints are loose or damaged.
6.12 Paint film adhesion
Use the tool specified in GB/T 9286, to mark 6 positions on the cantilever using the
grid method. Select four points on the pillar (or jib) for testing. When making grid, the
tool shall be perpendicular to the measured surface; the force shall be even. After
making grid, use a soft brush to gently brush three times in the diagonal direction in
both the forward and reverse directions. Then check the area of paint peeling. If more
than eight places meet the level 1 quality requirements in GB/T 9286, it is qualified.
7 Inspection rules
7.1 Classification
The inspection of cranes is divided into exit-factory inspection and type test.
7.2 Exit-factory inspection
7.2.1 Crane manufacturers shall take effective measures, to ensure the correctness of
the overall assembly of all parts at the site of use.
7.2.2 The manufacturer's quality inspection department shall conduct item-by-item
inspections according to the product drawings and this standard. Only after the
inspection is qualified will it be accepted and the "Product qualification certificate" will
be issued to the user.
7.2.3 Exit-factory inspection items are as follows:
a) The exit-factory inspection items of pillar jib cranes, wall jib cranes, wall-pillar
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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