Selection and Safety Performance Analysis of Crane Brakes

The complex working environments of cranes necessitate careful selection of safe and reliable brake systems. As a core component, the performance of crane brakes directly impacts the daily operational efficiency and construction productivity of cranes. Therefore, it is of great significance to strengthen the selection and safety performance analysis of crane brakes.

This comprehensive guide will delve into the design principles, safety considerations, inspection procedures, and troubleshooting techniques for crane brakes. We will pay particular attention to crane brake components, brake coils, and the overall performance of crane brake systems.

Crane Brake Design Principles

The design of crane brakes is influenced by various factors, including load capacity, operating speed, and environmental conditions. Generally, crane brakes are designed using fail-safe electromagnetic friction brakes. Under high-speed operation of motors and reducers, the performance of fail-safe electromagnetic friction brakes can be fully utilized. Common types of crane brakes include:

• Disc brakes: Characterized by their reliability and heat dissipation capabilities, disc brakes are widely used in cranes.
• Drum brakes: Offering high torque capacity, drum brakes are commonly found in heavy-duty applications.
• Electromagnetic brakes: These brakes provide rapid response times and are often used in applications requiring precise control.

Safety Considerations in Crane Brake Selection

For standardized brakes, certain principles must be adhered to during design and selection, including standardization, practicality, and safety. These principles aim to reduce the likelihood of failure in real-world applications.

Standardization Principle

Given the widespread use of crane brakes in various applications, it is common to choose standardized brakes unless there are specific requirements for a particular crane project. Brake selection should strictly adhere to national standards. Furthermore, as different crane models and types have varying brake specifications, it is crucial to pay close attention to the dimensions and specifications of the crane brake. Non-standard dimensions not only hinder installation but also pose significant safety risks during operation.

Safety Principle

A primary consideration when selecting crane brakes is their safety performance in actual applications. The analysis of a crane brake’s practical performance is essential to ensure its reliability and safety. Given the heavy workload and large loads that cranes handle, the materials used in crane brake construction must meet stringent requirements for stiffness and safety. If conditions permit, performance testing, particularly for core components such as brake levers, brake arms, and springs, should be conducted to ensure compliance with national standards.

Compatibility Principle

As a core component of a crane, the brake is directly or indirectly linked to other components. Therefore, it is essential to carefully evaluate the compatibility of the crane brake with other components. During brake selection, full consideration should be given to the matching of various systems within the crane, and whether the brake meets compatibility standards, including system performance and application environment.

Crane Brake Inspection

Regular inspections are crucial for maintaining the safety and efficiency of crane brakes.

Overall Inspection

Inspect the entire brake system for smooth operation. Subsequently, check the contact condition of the brake electromagnet core. During the electromagnetic inspection, the flexibility of the magnet core can be tested by pressing it with a wrench. The brake arm should be rocked to observe any signs of wear, and it should be repaired or replaced regularly as it is a major wear part.

For long-stroke brakes, the stationary and dynamic iron cores can be inspected using the cement layer exclusion method (implemented at the bottom of the brake). Special cement can also be used to increase the firmness.

Brake Band Inspection

As a transmission component and a major wear point in the brake system, the brake band requires regular inspection. During inspection, ensure that the rivets of the brake band do not protrude, as this can cause severe damage, excessive wear, and even brake failure or component bending. Therefore, the wear condition of the brake band should be closely monitored, and the band should be replaced regularly.

Brake Wheel Inspection

As a critical component of the drive system, the brake wheel must be inspected regularly to ensure its integrity. Due to long-term contact with the brake band and the bearing of heavy loads, the brake wheel is prone to cracking. If cracks are found, the wheel must be replaced.

During inspection, pay particular attention to the taper hole and shaft areas to ensure their tightness. If looseness is detected, the components should be disassembled for inspection. After inspection, the brake wheel should be cleaned with kerosene to prevent accidents caused by oil or contaminants.

Additionally, a temperature sensor can be installed on the drive device to ensure that the operating temperature of the brake wheel remains below 200°C.

Crane Brake Troubleshooting

Due to the complex internal structure of brakes, failures can occur during prolonged use. It is necessary to troubleshoot these failures and adopt appropriate maintenance methods or replacements to ensure the performance of the crane in actual use.

Insufficient Braking Force

Insufficient braking force, a common issue in crane operations, can stem from various factors, primarily related to brake wheel problems. Excessive wear, loose springs, dirt, or inadequate lubrication on the brake wheel can significantly reduce braking force. Given the critical role of the brake wheel in ensuring crane safety, thorough inspections are essential.

Sudden Brake Failure

During the daily use of cranes, sudden brake failures can occur, which is very dangerous and can lead to high-altitude falls.

The main cause of brake failure is the brake band, usually due to brake pad detachment or spring failure. Although the probability of brake damage is relatively low, it can still occur.

When troubleshooting this type of problem, it is usually necessary to replace or repair damaged components, such as the brake band, and adjust the relevant parameters of the brake to ensure that the operating parameters meet the actual application standards, thereby improving production safety.

Excessive Brake Wheel Temperature

Although the operating temperature of the brake wheel should be below 200°C, due to improper installation or adjustment, the brake band may not fully disengage from the brake wheel even when the brake is released, resulting in continuous friction. This can cause the brake wheel temperature to rise above 300°C within 5 minutes, causing the brake band to smoke.

In such cases, the brake caliper should be adjusted to center the brake band with the brake wheel, ensuring that the gaps on both sides are equal and that the braking torque surfaces of the brake band and brake wheel are parallel.

Inability to Open Brake Arm

During normal crane operation, the brake arm may fail to open when activated. The main causes of this problem include malfunctions of the various hinge points, circuit failures or breaks during operation, insufficient voltage, and burned coils or rectifier components.

These issues require a comprehensive inspection. During routine maintenance of the brake caliper, special attention should be paid to the various hinge points, which should be lubricated with thin oil to reduce wear on the brake arm and prevent it from failing to operate.

Selecting the Right Brake Coil for Crane

Proper selection, inspection, and maintenance of crane brakes are vital for ensuring the safe and efficient operation of cranes. By understanding the design principles, safety considerations, and potential issues, crane operators and maintenance personnel can minimize the risk of accidents and maximize equipment uptime.

CPTC is a professional tower crane parts manufacturer committed to providing comprehensive tower crane spare parts that fully meet customers’ safety, stability, and reliability requirements. If you have any questions about your crane brake selection, please feel free to contact us.