Avoid Safety Hazards When Operating Overhead Cranes

Main Factors of Crane Operation Accidents

In daily lifting operations, common accidents that cause injury to people include decoupling and smashing people, wire rope breakage and injury, mobile spreader hitting people, pulley smashing people, overturning accidents, falling accidents, and lifting equipment falling off accidents. There are many reasons for these accidents, but there are mainly two reasons: operational factors and equipment factors.

The main operating factors are:

The main equipment factors are:

Safety Devices for Lifting Appliances

Lifting machinery is a special equipment, and since its safety is very important, safety devices must be installed on the lifting machinery. Different types of cranes should be installed with different types and performance of safety devices. The more common safety devices are as follows:

  1. Overwind Limiter
According to the regulations, the hoisting mechanism of the crane must be equipped with an over-hoisting limiter. When the hook block is lifted 300mm away from the crane frame, the power supply of the motor can be automatically cut off and the motor will stop running. In this way, the safe operation of the crane can be ensured, and accidents such as the wire rope being pulled off and heavy objects falling can be avoided.

  2. Travel Limiter
It is a safety device adopted to prevent a collision accident caused by the crane approaching the end of the track, or a collision accident of two cranes on the same track. The travel limiter can ensure that when the distance between the end of the track is 200mm and the distance between the cranes is 500mm, the power supply is immediately cut off and the operation is stopped.

  3. Weight Limiter
Weight limiters are overload protection devices for cranes. According to its structure and working principle, it can be divided into two types: mechanical type and electronic type. During the lifting operation, when the lifting capacity exceeds 10% of the rated lifting capacity of the crane, the weight limiter will work to make the mechanism power off and stop working, thus playing the role of overload limit.

  4. Torque Limiter
For cranes with luffing boom, in addition to considering the size of the load, the change in the distance from the center of gravity of the load to the crane caused by the luffing of the boom should also be considered, that is, the problem of lifting moment. The torque limiter is a safety device that integrates the factors of the lifting capacity and the operating range of the crane to ensure that the lifting torque is always within the allowable range. It can be divided into two types: mechanical and electronic.
Mechanical torque limiters are available in lever and horizontal boom types. In the lifting operation, when the lifting weight increases to the limit value, the limiter can drive the control block to trigger the control switch to disconnect the power supply and stop working.
The electronic torque limiter can automatically compare the actual lifting torque with the rated lifting torque through the instrument during operation. If it is overloaded, the relay will automatically cut off the power supply of the working mechanism to ensure safety. The electronic torque limiter overcomes the shortcomings of the mechanical torque limiter and is widely used in various cranes.

  5. Automatic Interlock Device
There are many bare wires passing through the bridge crane. In order to prevent the maintenance personnel from getting electric shock, it is required to install an automatic interlocking device at the point where the cab leads to the vehicle (or bridge) to realize power failure during maintenance, and power on after the maintenance to ensure the safety of maintenance operations.

  6. Buffer
A buffer is a safety device that absorbs energy when a crane collides with an object, and works after the crane's brakes and end switches fail. When the crane is connected to the rail end column, ensure that the crane stops smoothly. Commonly used buffers on cranes include rubber buffers, spring buffers and hydraulic buffers.

  7. Brake
The brake on the lifting equipment can make the lifting equipment stop working at any time during the lifting, translation and rotation process and make the heavy objects stay at any height. It can prevent accidents and meet the working requirements. There are many types of brakes, such as spring-loaded brakes, safety cranks, etc. Because the function of the brake is very important for the crane, many accidents are often caused by the failure of the brake or the occurrence of applause. Therefore, in order to ensure the safety of lifting operations, the inspection and maintenance of brakes must be strengthened, and inspections are generally required once per shift.

  8. Dangerous Voltage Alarm
When the jib crane works near the power line, due to improper operation, the jib wire rope is too close to or even touches the wire, which will cause an electric shock accident. In order to prevent such accidents, a dangerous voltage alarm has been developed. The principle is: the transmission line of the alarm is three-phase alternating current, the phase difference between each phase is 120°, and the spatial electric field distribution is an alternating electric field. Points equidistant from each other should have zero potential. However, in actual line layout, there is no point where the potential is zero. According to the distribution characteristics of the electric field, as long as the absolute value and potential gradient of the touch potential are detected and compared with the preset reference voltage, the distance between the boom and the wire can be judged and timely Send out a warning.
The alarm consists of a detector and a siren. The detector is installed at the end of the crane arm, and the metal ball at the upper end acts as a detection probe, which can detect the electric field around the wire. The preamplifier inside the detector amplifies the weak electric field signal and sends it to the alarm for comparison processing.

Why Custom a Crane Solution?

At Yuantai, we know that there is no "one size fits all" in the lifting field. Universal cranes are suitable for general factories, warehouses, etc. Besides, different applications have different needs for cranes. For example, steel industries often lift steel plates, so need electromagnetic cranes. Ports and docks often need to load ore, gravel, and other bulk goods, so need to grab bucket cranes. Chemical dangerous places often need to carry flammable and explosive materials, so need explosion proof cranes.

So, we provide customized cranes according to the special needs of our customers. Custom crane solutions offer many benefits in a variety of applications：

Hoist

Overhead Crane

Gantry Crane

Jib Crane

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I'm happy to help you with a crane solution and pricing. Please provide me with the following crane specifications:

1. What type of overhead cranes do you need? (i.e., overhead crane, gantry crane, etc.)
2. What lifting capacity do you need for your overhead crane?
3. What span of crane do you need? 
4. What lifting height of overhead cranes do you need? 
5. What material will the crane lift? (i.e., steel, concrete, etc.)
6. Will the crane be used indoors or outdoors?
7. Any special requirements for the crane? (i.e., explosion-proof, etc.)

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