Safety maintenance of bridge crane

Safety maintenance of bridge crane

bridge crane is a kind of hoisting and transportation machinery commonly used in factories, accounting for about 80% of the total number of cranes. Therefore, its safety management and use are very important. The statistical results of relevant accidents show that the bridge crane causes the largest proportion of accidents. For example, according to the statistics of 42 lifting deaths and serious injuries, the accidents caused by bridge cranes account for 90% of all accidents. At present, our factory has ll bridge cranes with less oil and bubbles, and the rated load is 5 ~ 15 tons. In recent years, some unsafe factors affecting the performance of the equipment have been found in the process of daily use and management. If they are not handled in time, they may cause faults, affect the normal progress of production, or accidents. The following 7. Analyze various unsafe factors that may exist in the bridge crane at an oil drain port on the side of the oil source, so as to put forward effective treatment methods according to the actual problems of the equipment.

1 Composition of bridge crane

bridge crane is a device for lifting heavy objects with hook (also with grab or electromagnetic disc). Its appearance is in bridge shape, and both ends of the bridge are on the track through roller frames. The roller travels along the track to drive the movement of the bridge. Structurally, the bridge crane is mainly composed of three parts, namely metal structure, mechanical transmission and electrical equipment

(1) the metal structure is mainly composed of bridge, walkway, cab, etc. It mainly bears heavy load, places mechanical and electrical equipment, and forms the whole bridge crane

(2) the mechanical transmission part mainly includes the crane part and the trolley part. The crane part includes the crane operating mechanism, etc., and the trolley part includes the trolley frame operating mechanism, lifting mechanism, etc

(3) electrical equipment mainly includes protection panel (distribution panel), controller, collector (power supply sliding line), motor lighting, various limiters, interlocking switches, grounding and other safety protection devices

2 safety protection of bridge crane to reduce the use of auxiliaries

the bridge operating mechanism and trolley frame elevator of bridge crane are in places that are inconvenient for regular inspection. According to relevant regulations, they must be managed according to the type of special equipment. First, according to relevant regulations and in combination with the actual situation of the factory, the bridge cranes of all units in the factory shall be uniformly required to be equipped with overload limiter, lifting limit position limiter Safety protection devices such as rail sweeping plate and support frame, conductive sliding wire protection plate, grounding, rail end stop, etc. at the same time, the technical requirements of protection devices are formulated uniformly. For example:

(1) when the lifting load reaches 90% of the rated load, the system sends an alarm signal; When the lifting load reaches the rated load, the system can automatically cut off the power supply and send an alarm signal

(2) when the lifting appliance rises to the limit position, it shall be able to automatically cut off the lifting power supply

(3) a protective plate shall be set under the end beam at the sliding line end of the crane to prevent accidental contact between the spreader or steel wire rope and the sliding line: a protective plate shall be set between the ladder and the walking platform and the sliding line

(4) set a stop at the end of the track to prevent the derailment of the bridge

3 safety precautions for metal structure of bridge crane

during the use of bridge crane, it must be ensured that the bridge girder does not produce excessive downward deflection and permanent downward deflection deformation. (P) when the trolley is braking on its own, the motor will be "overloaded", which will cause the trolley to run down the slope, and the motor will not burn down again

(2) the transmission shaft of the traveling mechanism is twisted and subjected to too much force. The coupling connecting bolt is twisted and broken, and even the shaft is broken

(3) deformation of trolley rail, wheel slide and even trolley derailment; The cracks on the lower cover plate and web of the main beam seriously threaten the safe operation