Load Limit Switches 101

What are load limit switches?

Dillon load limit switches are overload protection devices used to ensure that the capacities of cranes and hoists are not exceeded. They can also be used as a load detection device by sending a signal to an alarm or light when reaching a specified load setting.

Dillon load limit switches can have up to 4 microswitches installed on them to perform functions such as:

• Alert you when you’ve reached a predefined minimum load or “slack” line
• Alert you when you’ve reached a predefined load threshold
• Alert you when you’ve reached a predefined maximum load
• Shut down the machinery when it’s reached a predefined minimum load or “slack” line
• Shut down the machinery when it’s reached a predefined maximum load

How do load limit switches work?

Dillon load limit switches work off the deflection of a pressure bar. During the calibration process, a specified load is applied to the pressure bar and the microswitches within that unit are adjusted to open or close a circuit when it reaches that load.

The MSI Clamp On Load Cell works off an electric current which sends a signal to a set of relays to open or close a circuit at a predetermined load. This unit can also be configured with a digital indicator that provides live load readings

Why are load limit switches important?

Load limit switches are crucial for creating a safe working environment–in fact, the Occupational Safety and Health Administration (OSHA) requires them to be used. Along with ensuring the safety of personnel, load limit switches can help you monitor a crane’s load to avoid exceeding its capacity, helping the equipment last longer and avoiding unnecessary damage or maintenance costs.

What are the different types of load limit switches Dillon offers?

There are two types of load limit switches: the inline and the clamp-on.

• The inline load limit switch (DynaSwitch) is installed at the dead-end of the line between the anchor point and the cable.
• The MSI Clamp On Load Cell is installed at the dead-end of the line and “clamped” on to the cable. It can also be used to continuously measure the load via a wired display.

What factors should I consider when selecting a load limit switch?

The cable diameter and  load capacity influence proper load limit switch selection. All our load limit switches are weather-proof, but consider whether you need an optional explosion-proof switch. If you’re not sure which solution is right for you, our expert team has decades of experience in a wide array of applications, and can help you find, configure, and implement the best load limit switch to meet your needs.