Inspection of crane safety devices

(1) Overload protection device.

Whether the overload protection device is sensitive and reliable, meets the design requirements, the opening pressure of the hydraulic overload protection device; whether the mechanical, electronic and integrated overload protector alarms and cuts off the comprehensive error of the power source set point.

(2) Torque limiter.

The torque limiter is a safety device for the boom type crane to prevent overcharging. Check the sensitivity of the torque limiter by the amplification method or the weight gain method, and check whether the torque limiter alarm and the cut-off power supply set point comprehensive error are within the specified range.

(3) Limit position limiter.

Check the luffing mechanism of the lifting equipment, whether the lifting mechanism and the running mechanism can reach the set position distance, whether the alarm signal can occur, and automatically cut off the power source running in the dangerous direction.

(4) Windproof device.

For cranes with a hinge height of more than 50 m at the root of the boom, the anemometer should be inspected, and it can be accurately alarmed when the wind speed set point is reached or the working limit wind speed is reached. Cranes operating in orbit on the open track should check the components of the rail clamps, iron shoes and anchoring devices for deformation, defects and the reliability of their independent work. For the automatic rail clamp, the reliability of the windproof function and the electric interlock switch function in the non-anchored state should be checked for the sudden gust windproof device and the large vehicle running brake.

(5) Anti-rollover device.

For boom luffing and boom type cranes, the reliability of the anti-backward device should be checked, the sensitivity of the electrical interlock should be checked, and the indication accuracy of the luffing position and amplitude indicator should be checked.

(6) Buffer.

For different types of cranes with different lifting speeds and running speeds, check whether the configured buffers match and check the integrity of the buffer and whether it can touch the stop at both ends.

(7) Protective devices.

Check whether all kinds of protective covers, guardrails, guards, ladders, etc. on the crane are complete and reliable. Exposed on the crane may cause winding and wounding, open drive; couplings, sprocket, chain, transmission belt and other rotating parts Whether there is a protective cover, a pedestrian passage on the crane, a ladder and a fence that may cause the exposed parts of the personnel to meet the requirements. The electrical equipment for open-air cranes shall be equipped with a rain cover.

5 electrical control device

(1) Control device.

It should be checked whether the electrical accessories are complete and complete, whether the mechanical fixing is firm, no looseness, no jamming; the power supply cable is not aged or exposed; the insulating material should be good. No damage and deterioration; bolted contacts, brushes and other joints should be reliable; the electrical equipment and electrical components selected on the crane should be compatible with the power supply and working environment and working conditions. For the bare wire power supply, check whether the external coloring and indicator settings meet the requirements; for the soft cable power supply, check whether the cable is properly retracted; check the collector cable for the entire length of the cable without bending, no jamming contact is reliable.

(2) Electrical protection.

An easy-to-operate main disconnector shall be provided at the entrance of the crane. An emergency power-off switch shall be provided on the crane and the total power supply shall be cut off. Check the crane power supply and various mechanisms for short-circuit protection, voltage loss protection, zero protection, over-current protection and over-speed and loss-of-magnetic protection for special cranes. Check the complete effectiveness of protective devices such as electrical interlocks, interlocks, and self-locking. Check the insulation resistance of the electrical circuit, whether the grounding of the electrical equipment and the grounding resistance of the metal structure meet the requirements. All metal equipment on the crane, such as the normal uncharged metal casing, transformer core and metal isolation layer, threaded metal pipe groove, cable metal sheath and other metal structures shall have reliable grounding (zero) protection.

6 metal structure

The main stressed members should be inspected for overall or local instability, fatigue deformation, cracks, severe corrosion and other phenomena. The connection of the metal structure and the weld joint have obvious deformation and cracking. Bolts or riveted connections shall not have any defects such as looseness or defects. Whether the high-strength bolt connection has sufficient pre-tightening force. The overall anti-corrosion coating of the metal structure should be good.

7 driver's cab

The suspension and support connection of the driver's cab should be checked for firmness and reliability. The door lock and door electrical interlock switch of the driver's cab, insulated floor and dry powder fire extinguisher should be fully equipped and effective. For cranes with harmful environment such as dust, poison, radiation, noise, high temperature, etc., it is necessary to check whether necessary protective devices for protecting the health of drivers are added. Driver room lighting and inspection lights must use a safe voltage of 36V or less.

8 safety signs

The crane lifting weight sign shall be inspected, and the safety inspection conformity mark of the technical supervision department shall be hung in the obvious part. Large car slides, sweeping boards, cable reels, spreaders, trolleys, rail clamps, slip line guards, booms, crane balance arms, boom heads, outriggers, bridges with pedestrian passages Whether the outside of the end frame of the crane, etc., is sprayed with the safety mark color as required.

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