Compared with ordinary cranes, gantry cranes nor only have high loading and unloading efficiency, large working space, and low operating costs, but have been widely used in many industries, but there are certain hidden dangerous found in the safety inspection work.
1. Channels and platforms
All the operating parts on the crane and the parts that require frequent inspection and maintenance (including the pulley and the moving part at the top of the boom), where more than 2m from the ground, should be reached by the inclined ladder(or stairs), platform, channel or straight ladder, and the guardrail should be installed on both sides of the ladder.
Where the height difference is more than 0.5m, the path should be made of inclined stairs or straight stairs. Footboards may be provided in vertical surfaces not exceeding 2m in height (for example, between the walking platform of the main beam of the bridge and the end beam), and handrails shall be provided on both sides of the footboards.
2. Hook, wire rope
When the use conditions or operation methods will lead to the accidental dishook of heavy objects, should be used anti-dishook with a locking device; when the hook is in danger of being caught by other items during the lifting process, safety hooks or other effective measures should be adopted.
The wire rope should be neatly arranged on the reel in order. Reel winding only agenda wire rope should be made rope groove. The drum used for multi-layer winding should adopt the suitable rope arrangement device or the flange guide structure to facilitate the automatic winding of the wire rope. When the hoisting mechanism uses multiple(even number) steel cables, it is appropriate to choose a steel wire rope with symmetry and symmetrical layout.
The laying of the crane roadbed and track should comply with the factory regulations, and the ground resistance of the track should not be greater than 4Ω.
The track should be straight, the fishplate connection bolts should be loose, and there should be no obstacles in the track and crane operating range. The gantry crane should release the rail clamp.
4. Safety devices
The crane and lifting trolley (except the suspended electric hoist trolley), should be installed in each running direction of the running travel limit, in the design of the limit position automatically cut off the forward direction of the power source. When the operating speed is greater than 100m/min, or the parking positioning requirements are stricter, it is appropriate to install a two-stage operating travel limit according to the need, the first sends a deceleration signal and shows down according to the requirements of the regulations, the second level should be able to automatically power off and stop.
The operating mechanism of the crane running on the track, the mechanism of the lifting trolley and the amplitude changing mechanism of the crane should be equipped changing mechanism of the crane should be equipped with a buffer device, and the buffer device can be installed on the crane or the stop device at the end of the track.
The lifting weight limit should be installed for the power driven lifting machinery of 1t and above without overturning danger. A weight limiter should also be installed for lifting machinery that is in danger of overturning and does not change its rated lifting weight within a certain range pf amplitude change.
The contact surface of the high-strength bolted connection members should be treated accordingly according to the design requirements, and should be kept dry and clean, without flash, burr, welding splash, welding scar, oxide sheet, dirt, etc., for the design requirements, the contact surface should not be painted.
6. Electrical safety
The inlet and outlet cables of the power distribution box and switch box should be fixed with cable cards. The inlet and outlet cables should be insulated with shears and fixed to the box. Do not contact the box directly. The inlet and outlet cables of the mobile distribution box and switch box shall be rubber sheathed insulated cables without connectors.
7. Working environment and appearance
Cranes shall have markings, labels and safety signs.
Rated lifting weight(or rated lifting torque) should be permanently marked. For cranes with rated lifted weight varying with the full range, there should be a visible curve or table with rated lifting weight varying with the full range; where different amplitude segments provide for different rated lifting weights, the division of amplitude segments and the rated lifting weights of each segment shall be permanently marked and clearly visible. The operating instructions provided by the manufacturer should be able to give a more detailed description of the different lifting ranges.
8. Main parts
The manufacturing unit or the installation and construction unit shall conduct welding process evaluation on the combination conditions of various parameters such as the type of steel used for the first time, welding material, welding method, joint form, welding position post-welding heat treatment process, welding parameters, preheating pr post-heating process measures.
Surface cracks and other defects affecting performance:(1) the thickness of the rim is worn up to 50% of the original thickness; (2) the bending deformation of the rim reaches 20% of the original thickness; (3) tread thickness wear up to 15% of the original thickness; (4) when the running speed is less than 50m/min, the roundness reaches 1mm; when the running speed is higher than 50m/min, the roundless reaches 0.1mm.