Case analysis of hand chain hoist safety lock failure

Case analysis of hand chain hoist safety lock failure: improving the safety awareness of international wholesale buyers

Introduction
In international trade, hand chain hoists are a common lifting equipment and are widely used in factories, warehouses, construction sites and other places to lift goods and equipment. However, as a key safety device, the safety lock of the hand chain hoist may cause serious safety accidents once it fails, causing huge losses to enterprises and customers. This article will analyze multiple cases of hand chain hoist safety lock failures, explore its causes, effects and preventive measures, aiming to improve international wholesale buyers' awareness of hand chain hoist safety lock failures, ensure the safe use of equipment, and thus improve the inclusion and exposure of the website.

Case 1: Equipment damage caused by the breakage of the main lifting chain of the hand chain hoist
Accident process
On the afternoon of March 29, 2018, Tang, the captain of a construction team in the electromechanical workshop of a shipyard, led Liu, Zhang and others to lift the ballast water treatment equipment (2630KG) into the engine room on a repair ship. After the equipment was hoisted to the NO.7 cabin of the ship with a 22T crane, it was transferred to the cabin from the process hole on the rear wall of the NO.7 cabin with a hand chain hoist. During the equipment transfer and relocation process, the main lifting chain of a 1T pulling hoist at the back suddenly broke, and the equipment under force slid forward about 0.4 meters, and finally hit the cabin wall, causing damage to the front end of the equipment. Fortunately, no personal injury was caused.
Cause Analysis
The direct reason was that the construction team used a hand chain hoist to transfer the equipment, the scheme selection was unreasonable, and the lifting center of gravity was improperly selected, resulting in excessive force on the main lifting chain of the 1T hand chain hoist used for pulling insurance, which in turn caused the main chain ring with old injuries to break. The main reasons include inadequate planning for equipment lifting and relocation, unreasonable selection of lifting schemes, failure to implement equipment anti-collision measures, poor command signals during operation, and the selected insurance hoist was too small and had old injuries. The indirect reasons are that the construction team did not implement safety measures before the operation and the pre-work preparation was not sufficient; the communication during the operation was not smooth, and the actions of the operators were not coordinated; the lifting tools and equipment were not carefully checked before use, and there were defects; the project management personnel did not have enough on-site control and failed to promptly discover and correct problems in the lifting process.
Lessons and preventive measures
Before construction, the equipment lifting plan should be carefully planned to ensure that the plan is feasible. All construction personnel must understand the planning content and strictly follow the plan. Formulate lifting operation benchmarks, which are detailed to the lifting of various types of equipment. Management personnel and all full-time lifting operators must learn and master the operation benchmarks and relevant knowledge in mechanics. Make a display example of the hand chain hoist pulling dynamometer, organize all crane operators to carry out practical training on the hand chain hoist multi-person coordinated operation, and emphasize the unified and smooth command signals. Strictly implement tool and equipment inspections, check and confirm before each use, and promptly implement rectification when problems are found to ensure the safety of the objects. Project management personnel should strengthen on-site safety control and urge construction personnel to implement safety precautions in accordance with regulatory requirements.

Case 2: Improper operation of hand chain hoist in a narrow space leads to fatal accident caused by people being hit by objects
Accident process
At about 16:50 on November 20, 2014, Xiao and Tang, two fitters of a construction team in the electromechanical area of ​​a shipyard, were installing a hydraulic pump in the cable room on the left side of the stern of a construction project. They untied the hook of the 2T hand chain hoist hanging on the upper ear hole of the hydraulic pump that was already in an upright state, and moved the hook to the bottom of the hydraulic pump and hung it on the sling. When they pulled the hoist hard, the center of gravity of the hydraulic pump lost stability and fell, hitting Tang, who was standing between the hydraulic pump and the cabin reinforcement structure, to death.
Cause analysis
The direct cause was improper operation of the hand chain hoist when lifting the displacement equipment and the operator stood in the dead angle of the lifting to pull the hoist. Indirect causes include the insufficient horizontal spacing between the hook of the final hanging point of the upper 3T hoist and the plane of the pump seat, and it was pressed on the top of the hydraulic pump, making it impossible to stand the hydraulic pump upright, and the wrong selection of the 3T hoist lifting point. During the operation, the two people did not make sufficient judgment on the risk of the pump tipping over. After removing the 2T hoist hook, they did not take alternative measures to prevent tipping, and believed that the pump body could be leaned on the wall plate to maintain stability. The two people did not prepare the tools fully before the operation, did not carry special tools for adjusting the bolt hole alignment, selected a large hand chain hoist, and the selection of the force point during the installation and positioning process was unreasonable. Both of them had obvious illegal operation behaviors during the operation, and the on-site operators had habitual violations.
Lessons and preventive measures
When performing hoisting operations in a small space, the safety operating procedures must be strictly followed to ensure the stability of the hoisting equipment. Before the operation, the risks must be fully assessed, and the lifting points and lifting tools must be reasonably selected to ensure the safety of the hoisting process. Strengthen the safety training of operators, improve their safety awareness and operating skills, and eliminate illegal operations. On-site managers should strengthen supervision, promptly discover and correct unsafe behaviors, and ensure the safety of the operation site.

Case 3: Hoisting accident caused by the failure of the hand chain hoist safety lock
Accident process
A factory used a hand chain hoist when performing equipment hoisting operations. During the lifting process, the safety lock of the hand chain hoist failed, causing the hoisted equipment to fall suddenly, almost causing casualties and equipment damage.
Cause Analysis
The investigation found that the safety lock of the hand chain hoist was not carefully checked before use, and there was wear and aging. During the lifting process, due to the shaking and impact of the equipment, the safety lock could not work properly, causing the equipment to fall. In addition, when using the hand chain hoist, the operator did not follow the operating procedures and failed to discover the abnormality of the safety lock in time.
Lessons and preventive measures
Before using the hand chain hoist, the hand chain hoist must be fully inspected, especially key components such as the safety lock, to ensure that it is intact. Regularly maintain and service the hand chain hoist, and replace worn parts in time. Strengthen safety training for operators to familiarize them with the operating procedures and safety precautions of the hand chain hoist and improve their emergency response capabilities. During the lifting operation, it is necessary to strictly follow the operating procedures to ensure the safety of the lifting process.

Case 4: Equipment damage accident caused by the failure of the safety lock of the hand chain hoist
Accident process
When a warehouse was using a hand chain hoist to lift goods, the safety lock of the hand chain hoist suddenly failed, causing the goods to fall, smashing some equipment and goods in the warehouse, causing great economic losses.
Cause analysis
During the long-term use of the safety lock of the hand chain hoist, due to lack of maintenance and care, the internal parts were severely worn and could not function normally. When lifting heavier goods, the pressure on the safety lock increased, which eventually led to the failure. At the same time, the warehouse management personnel did not properly manage the safety of the hand chain hoist, did not establish a regular inspection and maintenance system, and failed to discover and deal with the problem of the safety lock in time.
Lessons and preventive measures
The warehouse management department should establish and improve the safety management system of the hand chain hoist, regularly inspect, maintain and maintain the hand chain hoist to ensure that it is in good working condition. Strengthen safety training for warehouse operators to make them understand the safe use of hand chain hoists and the handling of common faults. Before lifting operations, carefully check the safety lock and other key components of the hand chain hoist, and deal with problems in time. It is strictly forbidden to use hand chain hoists with safety hazards for lifting operations.

Conclusion
The case analysis of hand chain hoist safety lock failure is of great significance to improving the safety awareness of international wholesale buyers. Through in-depth analysis of multiple actual cases, we learned that the reasons for the failure of hand chain hoist safety locks are diverse, including quality problems of the equipment itself, improper operation during use, lack of regular inspection and maintenance, etc. These cases provide us with valuable lessons and remind us that we must strictly abide by the safety operating procedures when using hand chain hoists and strengthen the management and maintenance of equipment.
In international trade, safety is always the first priority. Only by ensuring the safe use of equipment can the normal operation of the enterprise and the interests of customers be guaranteed. It is hoped that the analysis and suggestions in this article can provide useful references for users and buyers of hand chain hoists and jointly promote the safe development of the industry.