The Four Main Causes Of Crane Accidents

Types and causes of accidents of lifting machinery operations-the four main causes of crane accidents.

Modern lifting machinery structure has been to large-scale, precision, high efficiency, multi-functional, pleasant electromechanical integration direction. Over the years due to the design of lifting machinery, manufacturing, installation, use, maintenance and other lack of strict, scientific system of safety management, resulting in the occurrence of casualties in lifting machinery operations in the prominent. According to relevant statistics, China’s various regions and industries occur in the lifting machinery operations in the casualties, generally account for all casualties 1/5 ~ 1/3 In order to reduce the occurrence of accidents, to ensure safe production, so it must affect the safety of lifting machinery operations to find out the reasons for the analysis of accidents occurring in the regularity in order to take appropriate measures to achieve pre-control, targeting, and passive! For the initiative, prevention is better than cure.

Types and causes of accidents involving lifting machinery

Common types of accidents involving lifting machinery are: crushing accidents, electrocution accidents, falling accidents, hanging objects (with) falling accidents, body tipping accidents and special types of accidents.

First, crowded accident – the four main causes of crane accidents.

Squeeze injury accident refers to the lifting machine operation, the operator is squeezed between two objects, resulting in injuries, pressure injuries, injuries and other personal injury and death accidents.

The main reason for such accidents is the lack of safety supervision and command management personnel at the crane site, the site lifting operators and other operators lack of safety awareness and self-protection awareness, or barbaric operation and other human factors. Crush injuries occur mostly for the hoisting operators and maintenance personnel engaged in overhaul. There are several kinds of common injuries caused by crowding.

(a) Spreader or load and ground objects between the crowded accident

Workshops, warehouses and other indoor places, ground workers in large spreader or spreader and machinery and equipment, walls, bull legs columns and other obstacles between the narrow place, in the lifting, command, operation or engaged in other operations, due to the spreader drastic swinging impingement of the operators of the crowded accident occurred.

The main cause of such an accident:

① driver improper operation, operation of the speed of the organization changes too quickly, so that the lifting object (with) to produce greater inertia.

② command error, lifting route is not reasonable, resulting in lifting objects (with) in the violent swing extrusion, collision people.

(B) elevator equipment injuries caused by crowded accident

Building elevator maintenance personnel or operators, do not comply with the operating procedures, the occurrence of being squeezed in the cage and the well wall, derrick between the accident caused by extrusion injury also occurs from time to time.

(iii) Crush injuries between the machine and the building

In the inspection or maintenance of bridge crane operation is squeezed collision, that is, the operating personnel in the lifting machine and building (structure) between (such as standing in the bridge crane car running track or standing in the inspection walkway), by the operation of the lifting machine extrusion collision.

The main causes of such crushing accidents.

① inspection personnel or maintenance personnel and the driver lack of mutual contact.

② maintenance operations did not take the necessary safety precautions (such as fixing the crane in the crane operating range of devices), resulting in the driver rashly start the crane extrusion, collision.

(D) lifting objects (tools) placed on the unstable dumping of the crowded accident

The main cause of such injuries caused by crowded accidents.

① lifting objects (with) placed in an inappropriate way, on the major lifting objects (with) placed unstable, did not take the necessary safety protection measures.

② lifting operation site management is not good, resulting in lifting objects (with) suddenly tipped over and hit people.

(E) the body rotary injury accident

This type of accident occurs in the field operation of automobile, tire and crawler crane operations, often due to such operations of the crane slewing counterweight part of the lifting, commanding and other operating personnel injured or the above people squeezed in the crane counterweight and building between the injury.

This type of injury is mainly due to lifting, command and other operators stand improperly (such as standing between the slewing jib and the body) caused by the accident.

(F) flip impact injury accident

Engaged in lifting, turning, inverted operations, due to lifting method is not reasonable, mounting card is not secure, spreader selection is not appropriate, heavy tilt falling, lifting selection is not good, the command and the operator is not good, resulting in lifting the load instability, lifting the load swing impact, etc. will result in turning operations in the smashing, bumping, touching, squeezing, pressing and other casualties, this type of accident in the extrusion of the accident is particularly prominent.

Crane crushing accident is the most common casualties occurring in lifting machinery operations, the danger is great, the consequences are serious, often leading to death.

Second, electric shock accident – the four main causes of crane accidents.

Electrocution accident is to engage in lifting operations and maintenance operations of personnel, due to electric shock suffered by the electric shock occurred in personal injury and death. Most of the lifting machinery operations in the electric operating environment, electrocution is also a common casualty occurring in the lifting machinery operations. Crane work in the operator electrocution there are four main cases.

(A) the driver touches the clear contact line

When the crane driver’s room is set in the same side of the sliding contact line, the driver in the upper and lower crane touch the sliding contact line and electrocution.

The main cause of such electrocution:

① driver room location is not reasonable, generally should not be set up with the same side of the slip line.

② crane near the end of the sliding contact line is not set up on the side of the protective plate (net).

(B) crane in the open air operation of high-voltage transmission line contact

Open-air operation of mobile cranes in the high-voltage transmission lines or tower cranes in the high-voltage transmission lines next to the side of the boom, luffing and slewing process touched the high-voltage transmission lines, so that lifting machinery electrified, resulting in electrocution of the operator (electric shock).

The main causes of such electrocution accidents.

① crane in the high-voltage power lines (side) operation without taking the necessary safety measures (such as the installation of screen protection isolation).

② improper command, operating errors, resulting in lifting machinery electrocuted and charged.

The main causes of such electrocution.

① crane electrical facilities maintenance is not timely, leakage.

② the driver’s room is not set up to protect the safety of insulating pads, resulting in the driver due to leakage of facilities and electric shock (electric shock).

(D) lifting wire rope touching the slip contact line

Due to the skewed pulling and slanting hanging or lifting the process of lifting objects (with) swinging violently to lift the wire rope touching the sliding contact line, resulting in electrocution of the operator. The main cause of such electrocution accident:

① lifting method is not appropriate, crooked slant hanging violation of safety regulations.

② lifting machinery near the end of the contact line is not set up on the side of the sliding contact line protection plate, resulting in lifting the wire rope touching the sliding contact line and electrified, resulting in electrocution of the operator (electric shock).

Third, fall from height accident – the four main causes of crane accidents.

Fall from height accident mainly refers to personnel engaged in lifting machinery operations, from the crane body and other high altitude occurred down to the ground fall accident, including tools, parts and so on from the height of the fall will be the ground workers injured in the accident. Fall from height mainly occurs in the crane installation, maintenance operations. Crane operations in the operator falls from a height there are three main situations.

(A) repair cage fall

The main cause of such accidents:

① repair cage design structure is unreasonable (such as the height of the guard bar is not enough, the material selection does not meet the specified requirements, design strength is not enough, etc.).

② maintenance workers operate improperly, did not take the necessary safety measures (such as wearing a safety belt), resulting in maintenance cages and workers fell together.

(B) the road over the crane when the fall

The main cause of such accidents:

① maintenance workers did not take the necessary safety measures, take a chance not to wear a safety belt, due to foot slippage, obstacles to trip or crane suddenly start the shaking caused by the operator unsteady from the height of the fall to the ground and fall injuries.

② operator paralysis, work against the rules, resulting in a fall.

Installation or dismantling of lift able tower (section) type tower crane tower (section) of the operation, the tower (section) together with the operator fell. The main causes of such accidents are

① tower body (section) design structure is unreasonable (disassembly and installation of the fixed structure of the hidden problems).

② Improper disassembly and installation methods, operators and commanders with the wrong coordination, resulting in the tower (section) and the operators fell together.

(D) Body Impact Fall Accidents

This type of accident mostly occurs in maintenance operations, due to the lack of strict on-site safety supervision system, maintenance personnel were other operations of the crane end beam or cantilever impact, fall from height.

(E) maintenance tools, mold parts fall and injury accidents

In the high-altitude crane to engage in maintenance operations, often due to carelessness, so that the repair and replacement of parts or maintenance tools from the crane body slipped, smashed ground workers and machinery and equipment and other accidents.

Fourth, hanging objects (with) falling accidents – the four main causes of crane accidents.

Crane hoist (with) falling accident refers to lifting machinery operations, lifting loads, spreaders and other heavy objects falling from the air caused by personal injury and equipment destruction, referred to as the loss of the accident. Common lifting objects (gear) fall accident has five types.

(A) off-rope accident

The off-rope accident refers to the heavy objects from the bundled lifting ropes in the fall collapse of casualties occurred in the destruction of the accident. The main cause of the off-rope accident.

① the weight of the binding method and the essentials are not appropriate, resulting in the weight slipped off.

② lifting center of gravity selection is not appropriate, resulting in partial load lifting or lifting center is not stable so that the weight falls off.

(iii) the load was collision, impact and swaying, resulting in the loss of heavy objects, etc..

Unhooking accident refers to the loss of heavy loads caused by heavy loads, hoisting ropes or special spreaders coming out from the hook.

The main causes of unhooking accidents are

(1) The hook lacks a hook guard.

① Lack of hook guards. ② Failure of hook guards.

(iii) Improper lifting method and deformation of the hook opening, causing the opening to be too large.

(iv) Rope breakage

Rope breakage accident refers to the loss of heavy load caused by broken hoisting rope and hoisting rope.

The main reasons for breaking the hoisting rope:

(1) overload lifting and pulling off the wire rope. Due to the operator of the weight of the lifting object is not clear (such as lifting objects partially buried in the ground, frozen ground, ground bolt is not loosened, etc.), rash and blind lifting, overloading occurs to pull off the sling.

② lifting limit switch failure caused by over-roll pull off the wire rope.

③ oblique hanging, pulling diagonally caused by the rope squeeze cut off the wire rope, or due to the crooked pulling diagonally hanging overload and pull off the slinging device.

④ wire rope due to long-term use and lack of maintenance caused by fatigue and deformation, wear and tear damage to reach or exceed the end-of-life standard is still using the damage caused by the accident.

The main reasons for the breakage of sling rope.

① hook on the lifting rope angle is too large (〉1200)，No balance beam, so that the tension on the lifting rope more than the limit value and pull off.

② lifting wire rope species and specifications of improper selection, or still use the wire rope has reached the end of the standard bundling lifting loads caused by lifting rope breakage.

(iii) No protective measures were taken at the contact point between the rope and the sharp corners of the load, which caused the corners to cut the wire rope and caused the rope to break.

(iv) Hook breakage

A broken hook accident is an accident in which a heavy load is lost due to a broken hook. The main causes of hook breakage accidents:

① Defective material of hook.

① Defective hook material. ② Hooks are still in use due to long term wear and tear, which reduces the section size and reaches the end-of-life limit.

③ Frequent overloading caused by fatigue damage to fracture damage.

(E) Over-winding accident

Over windlass accident refers to the loss of heavy objects caused by the top of the hook. The main reasons for over-winding accident.

① No installation of limit position limiter or limiter failure, so that the hook continues to rise until the roll (pull) off the lifting wire rope.

② lifting mechanism of the main contactors failure (such as the main contact fusion, due to institutional failure or electromagnet core residual magnetism is too large Ambassador main contact release action is slow), can not be cut off in time to lift until the volume (pull) off the lifting rope.

Crane hoist (with) falling accidents mainly occur in the hoisting mechanism to take the winding system, in addition to the rope off, off the hook, broken rope, broken hook and over the winch, each hoisting wire rope ends of the fixing is also very important, such as the wire rope in the drum on the limit of the safety circle is guaranteed to be in the more than 2 laps; whether there is a fall limit protection; wire rope in the drum device on the pressure plate fixed and the module fixing whether it is safe and reliable. In addition the wire rope off the groove (out of the reel rope groove) or off the sheave (out of the pulley) accident will also happen to lose the accident.

Lift (gear) fall is the most common casualties occurring in lifting machinery operations, but also occurs in various types of lifting machinery operations with the universality of casualties, the danger is great, the consequences are very serious, often leading to death.