Chain Hoists are versatile pieces of equipment that are used for the lifting of various loads. Chain Hoists can be fixed on an overhead beam, or attached to a rail system to be movable throughout the facility. Chain Hoists are used in warehouses, maintenance, construction, and industrial applications and include manual, electrical, or air powered operations.
The load chain in the Hoist consists of interwoven formed or welded links. Manually operated hoists function by an operator grasping and pulling the load chain suspended from the hoist. As the operator pulls the chain, the load wheel turns and power is transmitted through the hoist gearing to the hoist load chain sprocket. Higher capacity manual chain hoists may have multiple chains suspended from the hoist and require multiple operators, each grasping and pulling one of the load chains.
Electric or air powered hoists function by an operator using a control device with push buttons that energizes a motor. The motor transmits power through the hoist gearing to the hoist load chain sprocket which moves the hoist load chain. The control device may also contain controls for emergency stops, power, overhead travel, and other motions or functions.
Chain Hoist Inspections
A designated person, selected by the employer, is responsible to inspect hoists before their initial use and on regular intervals to comply with ASME/ANSI B30.16.
The load chain should be cleaned and inspected before each use. Each link should be visually examined for any nicks, gouges, weathering, twisting or excessive wear. The hoist should not be operated if the load chain shows the existence of any type of damage and should be replaced.
The hooks and latches attached to the load chain will also need to be inspected. Deformation, cracks, excessive bends, twists, or wide throat opening indicate significant damage to the hook. Latches should have the proper pressure to spring back to the tip when released and remain tight against the hook. Hooks should be replaced if the latch does not engage properly. Hooks should always be replaced and never repaired. Welding or reshaping the hook will change the properties of the material and reduce the strength of the hook.
Chain Hoist Load Test
First, the hoist will need to be operated in the lifting and lowering directions without a load applied. The operation of the load chain and chain sprockets should be smooth and the braking and controls should work properly.
Next, a light load is attached on the hook (approximately 50 to 100 pounds) and operated normally. If the load chain binds, jumps, or is noisy, the chain should be inspected for proper lubrication and mating parts checked for wear, distortion, or other damage.
If the hoist works properly with the light load, the rated load or a load at least 125% of the rated capacity is connected to the hoist and the load is lifted clear of the floor. The load chain is then checked for wear and elongation by measuring a specific length of chain, called gauge length. The chain’s initial gauge length and the measured gauge length when the load chain should be replaced are normally outlined in the hoist’s operation manual.
If the load chain needs to be replaced, always use the manufacturer’s recommended load chain designed for the specific hoist. Load chain is not interchangeable between different manufacturers’ hoists, hoists with different load capacities, or with chain used for other purposes such as slings and load tie downs.
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