Maintenance is an essential for safe operation of hoists

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“In addition, hoists need a rated load test. In OSHA’s words, ‘Test loads shall not be more than 125% of the rated load unless otherwise recommended by the manufacturer. The test reports shall be placed on file where readily available to appointed personnel.”

That having been said—on smaller hoists at least—maintenance is less demanding now than it used to be. “Our range of electric hoists has been designed not to need too much maintenance,” says Hunter Golden, product manager at Ingersoll Rand. “Key to reducing maintenance is to operate the hoist within its designed window and duty cycle.”

There are some obvious things that you should do, for all hoist and lifting equipment:

“Check the chain and hook for wear and tear,” he says. “On a small hoist you can usually do that visually. The chain will need lubricating periodically. How often that will need to be done depends on the duty cycle, the environment it is working in, and the application it is used for. A more corrosive environment of course will need more frequent lubrications. But our chains now have magnesium phosphate coatings which makes them more corrosion resistant. It also makes them able to run with less lubricant and still function.”

Ingersoll Rand’s ELK series range from 1/8t to 2t capacities and is a modular design. “The modularity gives an advantage where maintenance is concerned,” says Golden. “Our three series of electric hoists all have the same basic design. The components are bigger for the higher capacity machines but the designs are essentially the same. So if you can maintain the small-capacity hoists, you can maintain the large capacity ones as well.

“They can be serviced in situ. We give full guidance in our literature; a competent mechanic can do it. The cover has been designed to be easy to remove. That gives access for maintenance to the pocket wheel and brake at one end of the hoist, and to the motor at the other.

“Our winches are IP65 protected, which means they are dustproof and water resistant. That of course increases safety and lifespan: you will not get grit wearing down the gear teeth.”

New materials, such as the manganese phosphate chain coatings mentioned above, have helped ease maintenance burdens. Other new materials, though, are less used in this sector. “The strength of metals is well-known and well-defined now,” he says. “Composites can lead to unknown territory.” The reliable workhorse that with regular maintenance goes on forever would seem to be made of metal.

Which is not to reject new technology. Digitalisation has greatly assisted in routine maintenance—mainly by giving warning of when servicing is due, and by sensing wear and tear in components and warning of it.

“We have an option for a cycle count device, which also records the number of hours of operation. The device has optional intelligence built in that monitors the core winding temperature of the motor, to tell you if it is overheating,” says Golden. “Those options are very popular in the rental environment. People hiring out their equipment want to know how much it has been used or abused.”

On larger-capacity hoists digital maintenance-aids go further. “One of the cornerstones of Industry 4.0 is predictive maintenance,” says Heike Metzger, marketing manager at Stahl CraneSystems. “In predictive maintenance the wear of individual parts can be calculated better, with the help of data collected on a system. This means that failures can be prevented with selective maintenance measures.”

Thus Stahl’s SMC multicontroller and remote condition monitoring system records the complete operating data of a hoist. As well as the total operating hours it monitors brakes, records speeds and load spectrum and full load hours, and calculates from that data the remaining service life. The data is transmitted wirelessly to a global server via a GSM connection; Stahl’s ConFig tool allows the data to be read out and evaluated on a computer. Authorised persons can then access the data worldwide and in real time.

Similarly, the crane management system from CMS supervises and collects crane status data continually, and helps report and analyse the cause of a fault or alarm. “This rationalises maintenance and management by preventive maintenance,” they say.

In larger hoists chains are replaced by wire rope. Its condition is absolutely critical. “The rope of course is part of the LOLER examination,” says Tensology’s Mordue, “and ISO 4309 is the relevant standard that covers how the rope must be inspected. It has tables that cover such things as the number of allowable broken wires, and gives guidance on when to change the rope.

“It applies to all kinds of cranes and hoists, and all kinds of industries, from big industries working offshore down to small workshops and garages. And it has changed recently. There had been a series of incidents that were worrying, so since 2017 the standard has included mandatory magnetic testing of wire ropes.

“It specifies magnetic testing because there is no other way that you can tell what is happening inside a rope. Visual inspection alone is now deemed unsatisfactory.”

A ‘competent person’ is required to perform the test. “A competent person is ‘someone who has theoretical knowledge and practical experience,” he says. “A lot of companies won’t have one; they can call in someone like ourselves. And wire is a somewhat specialised area, so an otherwise experienced engineer may not feel he has the competence. Sometimes an insurance company may send an inspector, or may ask for a second opinion.

“In fact we’ve found through the years that the gradual application of the load using bags is essential to achieving a controlled test environment as most problems or failures occur on the lifting equipment way before the full proof load is achieved. In those cases testing can be stopped and the problems mitigated and fixed before full proof load is swung through the entire testing criteria.”

One reason for using Water Weights, he says, is that the weight of the bags and load cells combined add up to only 1.5% of the rated test-load; so transporting them to your site and the associated manpower is very much less costly. “A typical 100t test performed with conventional weights would take five tractor-trailer loads and five men on site; with Water Weights it would need one pickup truck and two men on site.” An example of their flexibility is a recent 315t load test of an overhead bridge crane, carried out inside the turbine bay of a hydroelectric power plant in Georgia.

The overall message remains: maintenance will be easier, less costly, and more efficient if you treat your hoist with care and respect its limits of performance. Kindness, it seems, brings its own rewards.

Maintenance is an essential for safe operation of hoists