• Oct 21, 2024
• News

What factors affect the working radius or reach of a crane?

The working range of a crane is influenced by factors such as the length of the boom, the load, the lifting height, and so on.

The working radius, also referred to as the reach of a crane, is a critical factor in crane operations that defines how far a crane can lift and move a load from its base or center of rotation. Understanding the factors that affect the working radius of a crane is essential for safe and efficient lifting operations. Failure to account for these factors can lead to operational challenges, safety risks, and equipment damage. In this article, we’ll explore the key elements that influence the working radius or reach of a crane, providing you with a detailed guide for better project planning and execution.

1. Boom Length and Configuration

One of the primary factors that affect the working radius of a crane is the boom length. The boom is the long arm of the crane, which can be extended or retracted based on the lifting needs. Cranes with longer booms can reach farther but may have reduced lifting capacity due to the extended length.

• Telescopic Booms: Many cranes, especially mobile cranes, are equipped with telescopic booms, which can be adjusted to the desired length. As the boom is extended, the crane's capacity to lift heavier loads decreases, but its reach increases.
• Lattice Booms: Some cranes, like lattice boom cranes, consist of a fixed-length boom, which is designed for heavy-duty lifting over greater distances. While these provide increased stability and lifting power, they may not offer the same flexibility in reach adjustments as telescopic booms.

The boom length directly impacts the working radius, as a longer boom increases the horizontal distance between the crane’s base and the load. However, this increase in reach comes with trade-offs in stability and lifting capacity.

Impact of Boom Configuration on Reach:

The boom can also be configured at different angles. When the boom is extended to its full length and at a low angle, the crane’s reach is maximized, but its capacity is diminished. Conversely, a boom that is raised to a steep angle can lift heavier loads but with a reduced reach.

Calculation Consideration:

For telescopic or mobile cranes, the working radius can be calculated using a crane load chart, where both boom length and boom angle are key inputs. The relationship between boom length, boom angle, and reach is not linear, so a load chart is crucial to calculate the exact radius.

2. Boom Angle

The boom angle is another critical factor that affects the working radius of a crane. The boom angle refers to the angle between the boom and the ground. Lowering the boom increases the working radius, allowing the crane to reach farther horizontally. However, as the boom angle decreases, the lifting capacity diminishes due to the increased leverage required to lift the load at a longer distance.

Effect of Boom Angle on Capacity and Radius:

• A lower boom angle results in a longer working radius but a reduced lifting capacity.
• A higher boom angle decreases the working radius but allows the crane to lift heavier loads more securely.

In practical terms, adjusting the boom angle is a common method to change the reach of the crane during operations. However, operators must always reference the crane’s load chart to ensure that the capacity at the specific boom angle and length is not exceeded.

3. Counterweight and Stability

Cranes rely on counterweights to stabilize themselves during lifting operations. The placement and weight of the counterweight directly influence the crane’s reach and lifting capacity.

• A well-balanced crane with adequate counterweight can handle greater lifting capacities at longer reaches, while insufficient counterweight can drastically reduce both the reach and safety of the crane operation.
• Stability Considerations:
  • Ground Conditions: Uneven or unstable ground can negatively affect the crane’s stability, reducing its safe working radius. Operators must assess the ground conditions and, if necessary, use outrigger pads or mats to stabilize the crane.
  • Crane Base Size: The size and footprint of the crane base also play a role in stability. Cranes with larger bases or additional stabilization can handle longer reaches with greater safety.

4. Lift Height and Load Weight

The lift height and load weight are two interconnected factors that affect the crane’s working radius.

• Lift Height: The lift height refers to how high the crane needs to raise the load. As the height increases, the effective working radius may be reduced because the crane needs more power to lift the load vertically. If your factory has limited space and you want to maximize the lifting height, you may consider our low headroom hoist. This type of hoist can increase the lifting height by 200-500mm compared to a regular electric hoist, making it ideal for places with restricted ceiling height in factories.
• Load Weight: The weight of the load has a direct impact on the working radius. Heavier loads reduce the crane’s safe working radius because more force is required to move the load over longer distances.

As a general rule, the greater the load’s weight, the shorter the working radius of the crane. Operators must calculate both the vertical lift and horizontal movement to determine if the crane can safely handle the load at the required height and distance.

Load Charts and Crane Capacity:

Crane load charts show the maximum allowable load at various boom lengths and angles. They also account for the lift height, which can reduce the crane’s lifting capacity. The charts offer precise information on how weight and height impact the working radius, enabling operators to make informed decisions.

5. Wind and Environmental Conditions

Wind and other environmental conditions can have a significant effect on the crane’s working radius and overall safety. Wind applies additional force to the load and the boom, particularly when the load has a large surface area, such as a panel or beam. This force can increase as the crane reaches farther, reducing its effective working radius.

• Wind Speed: Higher wind speeds can make it dangerous to lift loads, especially at long distances. Wind exerts lateral pressure on the boom and can cause swaying, which reduces the control over the load.
• Load Shape: Loads with larger surface areas are more susceptible to wind pressure, further reducing the crane’s reach under windy conditions.

Most crane operations have wind limits specified by the manufacturer, and cranes may be rated for different capacities depending on the wind speed and the environment in which they operate.

6. Rigging Configuration

The rigging setup used to lift the load also affects the crane’s working radius. Proper rigging ensures that the load is evenly distributed and securely attached to the crane. Incorrect or imbalanced rigging can shorten the crane’s effective reach by introducing additional strain on the boom and affecting the center of gravity.

Operators must take into account the type of rigging equipment being used, such as slings, hooks, and shackles, and ensure that it can handle the weight and dimensions of the load. Improper rigging can lead to a reduction in both the crane’s capacity and its working radius.

Conclusion

In conclusion, the working radius or reach of a crane is influenced by several interrelated factors including boom length, boom angle, counterweight and stability, load weight, lift height, and environmental conditions. Proper planning and understanding of these factors are critical for safe and efficient crane operations. The working range of a crane is also a necessary factor to consider when selecting a model. If you would like to learn more about the selection process, you can check out our article on crane selection.