Top Running Overhead Crane In Warehouse

Top Running Overhead Crane In Warehouse
 

Bridge crane is a kind of hoisting and transportation machinery commonly used in factories, accounting for about 80% of all cranes. Therefore, its safe management and use are very important. The statistical results of accidents show that bridge cranes cause the largest proportion of accidents.
 

For example, according to the statistics of 42 lifting deaths and serious injury accidents, the accidents caused by bridge cranes accounted for 90% of all accidents. In the process of daily use and management, some unsafe factors that affect the performance of the equipment are found. If they are not dealt with in time, they may cause malfunctions, affect the normal production, or cause accidents.
 

The following analyzes the various unsafe factors that may exist in the bridge crane, so as to propose effective treatment methods based on the actual problems existing in the equipment.
 

 

1. The composition of the bridge crane
 

The bridge crane is a device that uses a hook (also useful for grabs or electromagnetic disks) to lift heavy objects. The appearance is bridge-shaped, and the two ends of the bridge frame are mounted on the track through rollers. The rollers walk along the track and drive the movement of the bridge. From the structural point of view, the bridge crane is mainly composed of three parts, namely metal structure, mechanical transmission and electrical equipment.
 

(1) The metal structure part is mainly composed of bridge frame, walking platform, cab and so on. It mainly bears heavy loads, houses mechanical and electrical equipment, and composes the bridge crane as a whole.
 

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

(3) Electrical equipment mainly includes safety protection devices such as protection panel (distribution panel), controller, collector (power supply slide wire), motor lighting, various limiters, interlock switches, and grounding.
 

2. Safety protection of bridge cranes
 

The bridge running mechanism and the trolley frame lift of the bridge crane are all inconvenient for frequent inspection, in accordance with relevant regulations. It must be managed according to the type of special equipment—according to the relevant regulations and combined with the actual situation of the factory, the bridge cranes of each unit in the factory are uniformly required to install overload limiters, limit position limiters for rising, rail sweeping plates and support frames, conductive Safety protection devices such as slide line protection boards, grounding, and track end stops, and the technical requirements for protection devices have been formulated uniformly. like:
 

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

(2) When the lifting gear is raised to the limit position, it should be able to automatically cut off the lifting power supply.
 

(3) Set up a protective plate under the end beam at the end of the sliding line of the cart to prevent accidental contact between the spreader or wire rope and the sliding line: set a protective plate 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 structures of bridge cranes
 

During the use of the bridge crane, it must be ensured that the main girder of the bridge frame does not produce excessive downdeflection and permanent downdeflection deformation. Otherwise, there will be the following hazards:
 

(1) Make the trolley "slip" by itself after braking, and cannot stop accurately. When the trolley climbs a slope, it will cause the motor to overload and burn out the motor.
 

(2) The transmission shaft of the traveling mechanism is twisted and subjected to excessive force. The coupling bolts will be twisted off, or even the shaft will be broken.
 

(3) The rails of the trolley are deformed, resulting in wheel slide rails, and even trolley derailment accidents; the lower cover and web of the main beam are cracked, which seriously threatens safe operation.
 

4. Safety precautions for the mechanical part of the bridge crane
 

The spare parts of the bridge crane must be checked regularly to avoid accidents
 

(1) The wear of the pulley groove is uneven, which can easily cause the wire rope pulley to contact evenly, and in severe cases, an operation accident will occur; if the wear of the pulley shaft exceeds the standard, it will easily cause the breakage of the pulley shaft. Once the wear exceeds the relevant regulations. must be replaced.
 

(2) If the wear of the reel exceeds the standard or fatigue cracks appear, it is easy to cause damage to the reel; if the key of the reel is severely worn, it is easy to cause the key to fall off or be cut off, and in severe cases, it is easy to cause heavy objects to fall. in this situation should be replaced
 

(3) The small shaft of the brake, the mandrel, the brake wheel, and the pad of the brake shoe are worn beyond the standard, and the fatigue cracks of the pull rod and the spring are likely to cause the brake to fail and should be replaced.
 

(4) If the wear of the dangerous section at the opening of the hook exceeds the standard or fatigue cracks appear on the tail, the thread relief groove at the tail, and the surface of the hook, it is easy to cause the breakage of the hook. Therefore, the hook garbage should be checked 1 to 3 times a year, and the problems found should be replaced in time
 

(5) If there are fatigue cracks on the spokes and treads of the crane wheels, or excessive wear on the wheel rims and treads, it is easy to cause damage to the wheels, and in severe cases, the crane will derail.
 

(6) If there is oil on the track, the motor starts too fast, and the wheel pressure is uneven, it is easy to cause the trolley running mechanism to slip; Uneven pressure is easy to cause the small wheels to be evenly stressed and must be adjusted.
 

(7) Regularly check the temperature, sound and lubrication of the bearings of each part of the crane; if the sound of the reducer is abnormal, it must be repaired or replaced in time
 

(8) If the deviation of the transmission system is too large, the frame is deflected and deformed, the installation error of the track and the wheel is too large, and oil is stored on the track, it is easy to cause the dog car to be gnawed, and it must be adjusted, cleaned and corrected in time.
 

 

5. Safety precautions for electrical equipment of bridge cranes
 

The driving motor of the bridge crane realizes the front and rear, left and right, and up and down movements of the hook through deceleration and transmission mechanisms. In order to ensure work safety, necessary electrical protection systems should be installed, such as main isolation switch, emergency power-off switch, short-circuit protection, Overload protection, limit protection, etc. It is necessary to regularly check the sound and heating of the motor, and whether the electromagnet is working normally.
 

Whether the controller and contactor are flexible and easy to use. It must be done: first, to prevent loss of control, heavy objects falling or impact accidents caused by incorrect operation or electrical failures such as controllers and protection panels; second, to prevent electric shock accidents caused by touching exposed power supply slide wires, insulation damage, and poor grounding; Especially in flammable and explosive places, explosion-proof electric cranes must be used.
 

6. Inspection and test of bridge type overweight crane
 

(1) In general, bridge cranes should be inspected once a year.
 

(2) All overhead cranes that are newly installed, overhauled, remodeled, and have been in normal use for two years or have been out of service for more than one year shall be tested in accordance with the hoisting machinery test regulations, and they can only be put into use after passing the test.
 

(3) Load tests include no-load test, static load test and dynamic load test.
 

7. Matters needing attention in inspection and test work
 

(1) Special personnel must be appointed to be responsible for inspection and testing work, and safety education must be given to relevant personnel before the work starts, so that they can understand the requirements of relevant regulations, and at the same time, the division of labor should be clearly defined.
 

(2) Carry out the final inspection of the bridge crane in accordance with the mechanical, electrical and high-altitude operation safety regulations
 

(3) When driving the car too much. Must be signaled by the commander after confirming safety before proceeding
 

(4) Only the commander is allowed to give the command signal, except that anyone can give the stop signal in urgent and dangerous situations.
 

(5) During the test, relevant personnel are to stand in a safe position.
 

(6) Emergency safety measures should be formulated in case of emergency danger

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