Requirements for metal structures in safety regulations for lifting appliances

Table des matières

The "Safety Regulations for Lifting Machinery" set out the most basic requirements for the safety requirements for the design, manufacture, inspection, scrapping, use and management of lifting machinery. Suitable for bridge cranes (including metallurgical cranes), gantry cranes , loading and unloading bridges, cable cranes, truck cranes, tire cranes, crawler cranes, railway cranes, tower cranes, mast cranes, lifts, electric hoists and simple lifting equipment and Assistive devices and so on. This article shares the basic requirements of the regulations for the metal structure of hoisting machinery.

1 Arrangement of structural parts

It should be easy to check, repair and drain.

2 Structural welding requirements

2.1 The quality of butt welds of main stress-bearing components, such as main beams, end beams, outriggers, towers, booms, etc., shall not be lower than the secondary welds in JB928-67 "Standard for Radiographic Inspection of Welds", or JB1152-81 "Ultrasonic flaw detection of butt welds of boilers and steel pressure vessels" stipulates the first-level welds.
2.2 The welding rod, welding wire and flux should be compatible with the material of the welded parts.
2.3 Welding rods should meet the requirements of GB981-76 "Low-carbon steel and low-alloy high-strength steel welding rods": the welds should comply with GB985-80 "Basic Types and Dimensions of Manual Arc Welding Joints" and GB986-80 "Submerged Arc Welding The basic types and dimensions of welded joints are stipulated in ".
2.4 Welding work must be performed by welders who have passed the examination. The welder's code stamp must be stamped near the weld of the main force-bearing member.

3 High-strength bolt connection

It must be handled according to the design and technical requirements and tightened with special tools.

4 Driver's cab

4.1 The cab must be safe and reliable. The connection between the cab and the suspension or supporting part must be firm.
4.2 The top of the cab should be able to withstand a static load of 2.5kN/cubic meter (250kgf/square meter).
4.3 For cranes working under high temperature, dust, toxic environment, etc., a closed driver's cab should be set up. For cranes that work in the open air, a driver’s cab that is wind-proof, rain-proof and sun-proof shall be provided.
4.4 The open driver’s cab should be provided with railings with a height of not less than 1050mm and should be reliably fenced.
4.5 Except for mobile cranes, the clearance height in the driver's cabin shall not be less than 2m.
4.6 Except for mobile cranes, when there is a platform outside the driver's room, the door should open outward; when there is no platform outside the driver's room, the door should open inward. Sliding sliding doors can be used with or without a platform outside the driver.
When the distance between the bottom of the driver's cab and the ground, passage, and platform is more than 2m, the platform should generally be set.
4.7 Except for the mobile crane and the starter that has no danger of touching people at the bottom of the driver, the clearance height of the bottom surface of the driver's cab that moves with the crane should not be less than 2m from the ground, passage, platform, etc. below.
4.8 The driver's cab of the bridge crane should generally be located on the side of the non-conductive bare slide line.
4.9 The structure and layout of the driver's cab should enable the driver to have a good view of the working area, and be convenient for operation and maintenance.
The driver’s cab should ensure that the driver can withdraw safely in the event of an accident, or avoid the hazard of the accident to the driver.
4.10 The layout of the cab windows should be such that all window glass can be cleaned safely.
The window glass should be tempered glass or laminated glass, and it should only be installed from the driver's cab.
4.11 Cranes whose internal working temperature is higher than 35℃ and working in high temperature environments, such as cranes used in metallurgy, should be equipped with cooling devices.
The driver's cab whose operating temperature is lower than 5°C shall be equipped with safe and reliable heating equipment.
4.12 The cab directly exposed to heat radiation in a high-temperature environment shall be provided with an effective thermal insulation layer. The heat-radiated window glass should be tempered glass that prevents infrared radiation.
4.13 The driver’s cab should be equipped with comfortable and adjustable seats, door locks, fire extinguishers and electric bells or alarms, and communication devices should also be provided when necessary.

5 Railing

The height should be 1050mm, and there should be horizontal crossbars with a spacing of 350mm. An enclosure with a height of not less than 70mm should be installed at the bottom.

Any place on the railing should be able to withstand 1kN (100kgf) load from any direction without plastic deformation.

For the railings installed on the boom for lubrication or maintenance in the air, the handrails should be able to hang the safety belt hook, and should be able to withstand a load of 4.5kN (450kgf) without being damaged.

6 Upright ladder

The distance between steps should be 300mm, and the distance between all steps should be equal; the distance between the step bar and the front elevation should not be less than 150mm, and the width of the ladder should not be less than 300mm.

When the height is greater than 10m, a resting platform shall be set every 6-8m; when the height is greater than 5m, a safety ring with a diameter of 650-800mm shall be installed from 2m, and the distance between two adjacent laps shall be 500mm. Between the safety rings, 5 uniformly distributed longitudinal connecting rods are used to connect.

Any position of the safety ring should be able to withstand a force of 1kN (100kgf) without breaking.

When the upright ladder leads to the upper platform with open edges, the tops of the handrails on both sides of the ladder should be 1050mm higher than the highest step rods, and the tops of the handrails should bend towards the platform.

7 Inclined ladder

It should be set according to the requirements of Table 1. In the whole inclined ladder, the spacing of all steps should be equal.

When the height of the inclined ladder is greater than 10m, a rest platform should be set at 7.5m. At future heights, rest platforms will be set up every 6-10m.

Railings should be provided on the side of the ladder.

Table 1 Requirements for Inclined Ladder

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Angle with horizontal plane (°)|20 |35 |40 |45 |50 |55 |60 |65

------------------|------|------|------|------|--- ---|------|------|------

Step spacing (mm) |160|175|185|200|210|225|235|245

Pedal width (mm) |310|280|249|226|208|180|160|145

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8 Walking platform on crane

The width (the distance from the railing to the maximum limit of the moving part) should not be less than 500mm for electric cranes, and should not be less than 400mm for manpower-driven cranes.

The clearance height of a platform with relatively moving components or objects above it should not be less than 1800mm.

The walking platform should be able to withstand the concentrated load of 3kN (300kgf) movement without plastic deformation.

9 non-slip

Ladder pedals and platform surfaces should have anti-slip properties.

10 Scrap of metal structures

10.1 When the main force-bearing component loses its overall stability, it should not be repaired and should be scrapped.
10.2 When the main force-bearing components are corroded, inspection and measurement shall be carried out. When the carrying capacity is reduced to 87% of the original design carrying capacity, if it cannot be repaired, it should be scrapped.
For units that have no computing power, when the section of the main force-bearing member corrodes to 10% of the original thickness, if it cannot be repaired, it shall be scrapped.
10.3 When cracks occur in the main stressed components, measures should be taken to prevent the cracks from continuing to expand according to the stress conditions and crack conditions, and measures to strengthen or change the stress distribution should be taken, or the use should be stopped.
10.4 When the main force-bearing component is plastically deformed and the working mechanism cannot operate normally and safely, if it cannot be repaired, it shall be scrapped.

For general bridge type cranes, when the trolley is in the middle of the span and under the rated load, the deflection of the main girder in the middle of the span

When the value of 1 is below the horizontal line and reaches the span ------, if it cannot be repaired at 700, it should be scrapped.

Relevant regulations on the metal structure of hoisting machinery are made to ensure the safety of the whole machine.