• Oct 14, 2024
• News

Overhead Crane Side Pulling Guide

Side pulling of the crane is dangerous and may lead to safety accidents. Measures need to be taken to reduce this risk.

Side pulling is a common issue encountered in the operation of overhead cranes and hoists. It refers to a situation where the load is lifted at an angle rather than vertically, placing excessive strain on the crane components and potentially creating dangerous working conditions. Overhead cranes are usually designed for vertical lifting, which means any horizontal force can jeopardize the safety and efficiency of crane operations.

Side pulling can happen unintentionally or due to improper crane usage, and it poses serious risks, including damage to equipment and potential injury to personnel. In this guide, we will explore the causes of side pulling, its dangers, and the necessary measures to prevent its occurrence.

Reasons for the Occurrence of Side Pulling

1. Operator Error: One of the most frequent causes of side pulling is operator error. This can happen when the crane operator moves the load while it is still on the ground or when the load is not positioned directly under the hoist. The operator might initiate a lift when the load is not correctly aligned with the crane's hook, causing a side pull.
2. Inadequate Load Positioning: If the load is not centered properly underneath the hoist, the lifting operation can cause side pulling. Overhead cranes are specifically designed to lift straight up and down. Any deviation from this path can cause a pull in a lateral direction, potentially leading to significant issues.
3. Environmental Factors: External environmental factors, such as wind or uneven terrain, can contribute to side pulling, especially in outdoor operations. Wind gusts can push the load off-center, causing side forces to act on the crane. Similarly, if the load is on an inclined surface, it may shift when lifted, introducing a side pull.
4. Defective or Misaligned Equipment: Sometimes, side pulling can occur due to equipment malfunctions. A worn-out hoist, misaligned components, or an improperly balanced load can result in an unintended horizontal force during a lifting operation. Equipment that is not adequately maintained is more prone to these issues.
5. Insufficient Training: A lack of proper training for crane operators and other personnel working with the crane is another common factor leading to side pulling. Operators may not fully understand the consequences of lifting loads from an off-center position or may not recognize when side pulling is occurring until it is too late.

Dangers of Side Pulling of Overhead Cranes

Side pulling is dangerous because it introduces risks that go beyond the design capabilities of overhead cranes. These cranes are specifically engineered for vertical lifting, and any horizontal force during lifting operations can compromise the crane’s stability and integrity. Below are some of the dangers associated with side pulling:

1. Structural Damage to the Crane: Overhead cranes and hoists are built to withstand vertical forces. When a side pull occurs, it places an unexpected horizontal force on components like the wire rope, drum, trolley, and hoist mechanism. Over time, these lateral forces can lead to accelerated wear and tear on the crane's structural elements. This can result in deformed or damaged parts, which may cause long-term equipment failure if not addressed.
2. Increased Risk of Load Dropping: One of the most serious risks of side pulling is the potential for dropping the load. Since the crane is not designed to handle side forces, the lifting apparatus may become unstable, increasing the chance that the hook will disengage or the wire rope will snap. A dropped load can cause significant damage to the work area, nearby equipment, or people.
3. Unstable Crane Movement: Side pulling can cause instability in the movement of the crane itself. For example, if the trolley or bridge moves while the load is being lifted at an angle, it may cause the crane to sway or jerk, further compounding the risk of accidents.
4. Increased Wear on Wire Rope and Drum: The wire rope is one of the most critical components of an overhead crane, and side pulling places undue stress on it. The rope may wind unevenly around the drum or experience additional friction, which could lead to fraying, twisting, or breaking. These problems not only reduce the lifespan of the wire rope but also present immediate safety hazards during operations.
5. Damage to Other Equipment or Infrastructure: When a side pull occurs, the load may swing uncontrollably, causing damage to surrounding equipment, walls, or machinery. This can lead to expensive repairs and downtime in the facility. Moreover, if the load collides with other structures, it could create additional hazards for anyone working nearby.

How to Avoid Side Pulling

Preventing side pulling requires both proper training and adherence to strict operational guidelines. Below are several steps to avoid side pulling and ensure the safe operation of overhead cranes:

1. Proper Operator Training: The most effective way to prevent side pulling is through thorough training of crane operators. They must understand the dangers of side pulling and be trained to recognize when a load is not properly aligned for vertical lifting. Training should also include detailed instructions on the correct positioning of loads and the use of the crane controls to avoid creating horizontal forces.
2. Pre-Lift Inspection and Load Positioning: Before any lift begins, operators should ensure that the load is centered directly under the crane's hook. Conducting pre-lift inspections to verify that the load is in the proper position is a critical step in avoiding side pulling. Operators should also check that the load is balanced and secure before initiating the lift.
3. Avoid Moving Loads on the Ground: Moving a load while it is still in contact with the ground is one of the main contributors to side pulling. Operators should refrain from dragging or pushing loads with the crane and should only lift when the load is fully suspended and balanced beneath the hoist.
4. Regular Maintenance and Inspection of Equipment: Ensuring that the crane and all its components are in proper working order is essential in preventing side pulling. Regular maintenance checks should focus on the hoist, wire rope, trolley alignment, and other key components. Any signs of wear, damage, or misalignment should be addressed immediately.
5. Use of Anti-Side Pull Devices: Modern cranes may be equipped with anti-side pull devices that can detect when a side pull is occurring and stop the lift to prevent further damage or injury. These devices can help to safeguard against operator error and mechanical issues that might otherwise lead to a side pull.
6. Monitoring Environmental Conditions: If the crane is being operated outdoors, operators must be mindful of weather conditions, especially high winds, that could push the load out of alignment. Waiting for favorable conditions or taking extra precautions during windy conditions can help prevent side pulling.

Conclusion

Side pulling is a serious issue that can compromise the safety of overhead crane operations and result in significant damage to equipment, loads, and potentially, people. It arises due to several factors, including operator error, improper load positioning, and external environmental factors. By recognizing the dangers associated with side pulling and taking steps to prevent it—such as proper training, equipment maintenance, and adherence to best practices—crane operators and facility managers can significantly reduce the risks. Preventive measures not only ensure a safer working environment but also prolong the operational lifespan of the crane and reduce costly repairs.