This article is Part 6 of a 7-part blog series that will cover what operators should consider when performing a pre-operational hoist safety inspection. Today, we’ll discuss operation inspection.
When testing the operation of the hoist, it’s important to test the upper and lower limits. A limiting device protects the hoist from getting damaged, from running the hook block into the hoist or running chain out of the hoist.
There are two types of hoists – hoists with a limit switch and hoists with a slip clutch.
If you have a hoist that uses a slip clutch in the up direction as its limiting device, like the CM ShopStar and the CM ValuStar, you should not do this test during your pre-operational inspection. This test would only be done during a periodic inspection.
If you have a hoist with a limit switch, you should conduct this test during your pre-operational inspection. If you are testing a two-speed hoist, you should test the limit switch at both speeds.
Before testing the limits of a powered hoist, there are a few safety precautions you should observe:
- Ensure the area under the hoist or crane is clear of obstructions. Also, check that there is no one under or in the path of the hoist, including yourself.
- Ensure there is not a load on the hoist.
- Be prepared to stop the hoist by releasing the controller.
After taking these precautions, follow these steps to test the hoist’s upper and lower limits:
- With no load on the hoist, start running up the hoist.
- Listen for strange noises.
- The limit switch should stop the hoist prior to the hook block hitting the hoist. If it fails to operate, or you think it will fail, do not run into the bottom of the hoist. This can damage the hoist.
- If the limit switch fails, the hoist needs to be removed from service.
- Next, lower the hoist hook to test the operation of the lower limit switch.
- Follow the same steps you took when testing the upper limit switch. As it is lowering, listen for unusual sounds.
- Check the chain or wire rope for defects.
- Again, if the limit switch fails, remove the hoist from service.
Testing your hoist’s upper and lower limits is an important part of your hoist pre-operational inspection. If at any time you have questions about the functioning of the limit switch on your hoist or think there is an issue, take the hoist out of service and contact the manufacturer.
Learn more about hoist inspection and maintenance