Empty hitting occurs when the piston of a hydraulic breaker moves without making contact with the chisel during operation. This phenomenon can lead to significant risks and damage to both the hydraulic breaker and its components. Understanding the hazards and implementing preventive measures is crucial for maintaining equipment integrity, ensuring safety, and optimizing performance.
Hazard Analysis
1. Component Damage
- Chisel Pin Failure: During empty hitting, the impact force intended for breaking material is instead transferred through internal components such as the chisel pin. This can cause the chisel pin to break under excessive stress.
- Cross Pin Cracks: The force is also dispersed to the cross pin of the chisel pin, leading to cracks around the inner hole edges, ultimately resulting in the fracture of the lower cylinder body.
2. Structural Failure
- Critical Part Fractures: Frequent empty hitting can cause critical parts like the front body, flat pin, bolts, guards, boom, and chisel to crack or break. Such structural failures reduce the efficiency of the hydraulic breaker and shorten its lifespan.
3. Hydraulic System Malfunction
- Leakage: Soft and hard hydraulic lines may develop leaks due to empty hitting, wasting valuable hydraulic fluid, causing environmental pollution, and increasing maintenance costs.
4. Energy Waste
- Heat Generation: In cases of complete empty hitting, where the piston does not contact the chisel at all, all the energy generated by the hydraulic system is converted into heat, doing no useful work and potentially overheating the equipment.
5. Accelerated Wear
- Increased Impact Forces: In incomplete empty hittings, even though the piston contacts the chisel, if the excavator is not properly stabilized, the entire assembly lifts, causing the chisel to retreat and move forward with the piston. Eventually, this results in the chisel hitting the flat pin. Throughout this process, the chisel, piston, flat pin, front cylinder body, and bolt rod all experience additional impact forces, accelerating wear.
- Catastrophic Failure: If the chisel is struck by the piston during its retraction, it can cause greater damage to the next flat pin, possibly leading to a catastrophic failure similar to a "blowout."
Causes of Empty Hitting
1. Operational Errors
- Improper Chisel Positioning: Before starting the hydraulic breaker, failing to ensure that the chisel is firmly pressed against the target material can easily result in empty hitting.
- Continued Operation After Material Breakage: Continuing to operate the breaker after the material has been broken can also lead to empty hitting.
2. Insufficient Maintenance
- Lack of Regular Checks: Even though the operator’s manual explicitly prohibits empty hitting, inadequate regular maintenance—such as not checking and adjusting the condition of various components—can indirectly lead to empty hitting.
Prevention Measures
1. Standardize Operating Procedures
- Follow Manufacturer Guidelines: Adhere closely to the instructions in the hydraulic breaker’s user manual. Before beginning work, ensure the chisel is securely pressed against the target material and maintain an optimal striking angle between 85 and 95 degrees. This ensures that each strike effectively transfers energy.
2. Enhance Operator Training
- Technical Training: Provide thorough technical training for operators to understand the dangers of empty hitting and how to operate the hydraulic breaker correctly. Increase their safety awareness and skill level to prevent operational errors.
3. Regular Inspection and Maintenance
- Comprehensive Inspections: Conduct regular comprehensive inspections of the hydraulic breaker, checking for issues such as loose high and low-pressure hoses, hydraulic fluid leaks, and proper nitrogen pressure. Address any problems promptly to avoid minor issues escalating into major failures.
4. Use High-Quality Components
- Select Certified Parts: Choose original or certified high-quality components, such as chisels, to reduce the risk of empty hitting caused by substandard parts.
5. Plan Operations Reasonably
- Match Equipment to Conditions: Select appropriate hydraulic breaker models and specifications based on actual working conditions. Avoid overloading the equipment beyond its capacity to reduce unnecessary stress.
Conclusion
While completely eliminating empty hitting is challenging, implementing standardized operations, enhancing operator training, conducting regular inspections and maintenance, and using high-quality components can significantly reduce the likelihood of empty hitting and mitigate its harmful effects. These measures help extend the service life of the hydraulic breaker, ensure safe and efficient construction, and protect the investment in the equipment.
