Weight Overload Protection

Many hoist users assume that their hoist has overload protection to prevent picking up more than the labeled capacity. This may be FALSE.



The specification governing electric chain hoists is ASME HST-1 – 2017 – Performance Standard for Electric Chain Hoists.  The specification governing electric wire rope hoist is ASME HST-4 – Performance Standard for Overhead Electric Wire Rope Hoist. These document do NOT specify that a hoist must have an overload limiting device.

If you want your hoist to have weight overload protection be sure to specify it.

When weight overload protection is specified, there are several methods that can be used:

Electro-Mechanical Devices

Electro-mechanical devices employ a spring arrangement or load beam arrangement that deflects at a certain load and trips a limit switch disabling the up lifting circuit on the hoist. These devices are generally installed at the chain or wire rope dead end connection. They allow for precise load limit settings with repeatable accuracy. They can take up hoist headroom depending on how they are mounted.

Dillon DynaSwitch (force beam with microswitch)

Harrington ER2 Load Limiter option (Bellville spring washers with microswitch)

Other Methods

There are a variety of other methods to detect overloads including devices that clamp to the wire rope and monitor rope tension.

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