Rigging it up29 July 2019
Julian Champkin looks at recent developments in the rigging and attachments sector.
When a technology is established and works well, there comes a point where evolution slows down because what has already evolved is very well fitted for purpose. A gamechanger— digitisation is one—transforms the environment, giving new opportunities for new products; but in the absence of that, change is slow, incremental and nonthreatening. So it is with rigging apparatus. “Below the hook technology in hoists only changes gradually,” says Ashley Thacker, general manager of Ranger Lifting in New South Wales, Australia, specialist suppliers of lifting and rigging equipment. “It is because the existing basic ideas have proved to work very well.”
Nevertheless, there are developments. One is an innovation that Ranger have devised and are introducing, and that Thacker believes could find more widespread use.
“It is our own invention,” he says. “It is uniquely Australian and does not seem to have travelled.” Perhaps it is about time that it did.
They call it the Plate Lifter, and it enhances safety and efficiency when placing or removing steel road plates, of the sort that are commonly used to cover holes during work on highways and other areas. The plates are strong enough for traffic to drive over them; they are correspondingly heavy; they have to be shifted often; they are usually flat and featureless and so traditionally they are lifted by crowbar or by hand.
“The traditional method is to use crowbars to lift an edge of the plate on either side to insert clamps, and then to apply rigging equipment. It is awkward and extremely slow,” says Thacker. “It is also unsafe. Back and other injuries, sometimes resulting in long periods off work, are common occurrences; I have worked with industry professionals who have broken, even lost, fingers by getting their hands trapped beneath the heavy plates.”
Ranger’s plate lifter system consists of a receiver plate and a lifting tool. The receiver is welded into the centre of each steel trench plate. It lies flush, eliminating any potential trip hazards and allowing plates to be stacked on top of each other for storage. The lifting tool is inserted into the receiver plate and locks into place. A hook can be attached directly through the elongated hole of the lifter. Road plate lifters are designed to be lifted straight up and down in a vertical line.
A portable hoist, or any vehicle-mounted or other crane that has an appropriate capacity based on the size and weight of the steel plate, can then do the lifting. Ranger commonly supplies 10mm or 13mm chain slings and spreader systems for the job when there is a requirement.
Road plates range in shape and size but are commonly 28mm to 40mm thick. Thacker explains that when using longer plates, it is recommended that two plate lifter tools be used with a spreader bar for stability and to minimise stress caused by bending of the plate.
“The plate should be measured in thirds along its longest part,” he says, “and a weld-in plate placed on each third division. In some instances, for stiffer road plates, two plates have been installed next to each other. We can consult on such matters on a case by case basis.”
An advantage is that no added shackle is required to attach the hook to it. “That allows for easy, quick and, most importantly, safe application. As the advantages of the system become apparent to more and more influencers and buying decision makers, we are seeing increasing demand for the plate lifter. Many contractors will now only employ road plates fitted with the tooling,” he says.
Growing popularity of the system has led to Ranger consulting with end users and steel merchants to get the system installed upon manufacture of the plates. This adds further efficiency to applications given that Ranger’s technical team currently visit sites to proof load each plate once the tooling has been welded into place.
Ranger is the sole distributor of this revolutionary system in Australia and New Zealand.
In similar vein, Caldwell's new Rig-master Reel Lifter provides a lightweight, easy to use tool that they say makes upending, lifting, and unreeling cable from a reel fast, easy, and efficient. It consists of a lifting arm that fits the hole in the reel’s centre, and a toggle that, once inside the hollow core of the reel opens out to prevent withdrawal, thus holding the reel in place. The reel can then be lifted or upended by the hoist, and the cable unwound. The reel is released by pulling a lanyard, which makes the toggle return to its position inside the arm. It is a simple idea, but effective. Four standard sizes are available in capacities from 500 to 11,000 pounds. It is made of heavy duty alloy steel that is rugged enough for demanding environments and requires little maintenance.
Securing any load to any hook usually requires some kind of lifting ring to be bolted on to the load. The bolt, of course, must be tightened correctly. Jergens, of Cleveland, Ohio, have introduced Lift- Check, a lifting bolt that automatically shows when it has been tightened to a safe tension. Tension measuring devices these days are usually digital. Unusually, this one is mechanical in operation, which makes it simpler to use and universal in application. Chris Spada, product manager, explains the advantages of the device.
“For years everyone has talked about the proper torque that should be given to a lifting-bolt to make it safe and secure to lift its load,” he says. The torque, of course, is measured by tightening the bolt with a torque-wrench—which itself has to be calibrated to ensure it gives a correct reading. Even given that, the procedure has flaws. “Torque is a rotational force,” says Spada. “What you really need to know is the tension in the bolt, that is, the linear force holding it against the load. Torque can be an indication of tension, but it is not an infallible indication.
“For example, if the bolt is screwed into a blind hole, and the hole is not deep enough, the end of the bolt will be pressing against the bottom of the hole. The torque readings can be as high and apparently safe as you like, but the arrangement is not actually safe: the load is not engaging on the underside of the bolt head. That means there is no pre-load. That in turn means that bending moments can occur between the bolt and the load, leading to stresses and possible failure. So torque is not in itself a fail-safe measure of secure fastening.
“People make calculations to convert torque readings to tension, and there is indeed a correlation between them; but it is not a direct correlation. So the calculations are fallible, and they are to an extent subjective. They depend on such things as the friction between the two parts. Some people use a friction factor of 0.19 for the calculation, some use 0.22; it can depend on whether you are working at high or low tolerances, or even on personal choice; and the choice can drastically change the calculation.”
Lift-Check, he says, eliminates those uncertainties. “It allows you to know directly that you have the proper tension and that you are good to go.”
The operator doesn’t even need a torque wrench, calibrated or not, to install it: an ordinary box wrench will do. An indicator panel on the top of the bolt is red, and stays red until it is screwed to the right tension. “At that point it turns black. That tells you that you are at the proper tension and that you are good to go,” says Spada. “Red means No, black means Go.” It is a direct, rather than an indirect, indicator of safety.
The bolts are re-useable. After the lift, when they are taken out, they should return to red; if they do not it is an indication that something has occurred that needs investigating. “We have all known the six-foot strongman who removes bolts after lifting with a crowbar and a sledge-hammer, and weakens them in the process. With conventional bolts there would be no way of telling that they had been damaged, so they would be used again for another—and might crack, unseen, while being tightened. Lift-Check bolts give an indication that something has occurred and needs checking; so they are a nice preventive safety measure for the next lift as well as for the current one,” says Spada.
Lift-Check lifting bolts and hoist rings come in load capacities from 2,500lbs to 7,000lbs (1t to 3t) and are rated at 5:1 strength factor and proof tested to 200% of rated load capacity.
Offshore lifting is more challenging, more high-tech, more cutting-edge, more hazardous and therefore much more fastmoving. A small improvement, in efficiency, ease or safety, can still yield large returns; consequently new developments, some of them radical, are frequent, and more the rule than the exception.
One such comes from William Hackett lifting products. It is widely accepted that certain types and grades of compliant lifting products that may be suitable for standard industrial applications are not suitable for offshore and subsea applications. Safety is paramount, which is why William Hackett advocates that equipment specifiers and users only consider products that the manufacturer warrants as suitable for use in offshore and in subsea environments.
Specialist manufacturers offer hoists with features making them suitable for use in subsea activities; among them, subsea lever hoists, in which William Hackett were pioneers.
Lever hoists are apparently-simple pieces of kit, but their obvious use—that of raising a load by pulling the lever—is by no means their only application. When a load hangs from two or more rigging chains going to a single hook—for example, via a spreader bar hook—it is important that the chains are the right length for the load to hang horizontally. You need to get the triangulation right. Chain lengths therefore need to be adjustable. One way of adjusting them is to insert a lever hoist as part of one of them. Pulling on the lever will shorten the effective length of the chain to give the geometry that is required. The lever hoist becomes part of the rigging.
This is common usage in land-based lifting. It is also used in sub-sea applications. The offshore industry has embraced lever hoists, but for them the historic industry norm is for a hoist to be used only once, for a limited time, and then recovered and quarantined from service or discarded. This may surprise those unfamiliar with the subsea industry; but loads can be large and valuable, installing them is expensive, the environment is hostile even at the best of times, and sea water is very corrosive; above all, safety must be paramount. Hence the single-use policy.
Single-use has of course disadvantages. It means that a project may require a large number of hoists to be purchased, transported, stored, allocated, recovered, and either inspected or destroyed. The cost and environmental impacts of this are significant. The necessity for and sustainability of the historic practices are now being successfully challenged and customer decision-making criteria are changing to reflect this.
Thus the second generation range of William Hackett lever hoist, and specifically their SS-L5 subsea lever hoist, has been designed to exceed the historic performance levels and meet safety criteria for hoists and rigging that are currently used subsea.
Based upon knowledge gained in first generation subsea hoists, on materials research and on technical development, William Hackett has raised the industry standard by providing a hoist that has been designed for multi-immersion use.
The company used all the relevant safety standards, from IMCA and others, as reference throughout the development of the SSL5 lever hoist. An extremely important step was when the company engaged Smith Lifting Consultants to design a rigorous but controlled testing regime and DNV-GL, the industry-leading verification organisation, to witness the testing and the results. The trials sought to demonstrate that the hoists could operate satisfactorily with minimal maintenance during and after multi-immersions in salt water, in contaminated salt water, and in suspended sand, and that they could successfully undergo a light-load test after multi immersions. The effects of thorough maintenance versus minimal maintenance over multi immersions were investigated, and it was examined whether the hoists were capable of being restored to factory condition after such immersions using service packs.
The testing, inspection and operational functionality tests were witnessed by DNV GL UK Limited and confirmed as satisfactorily passed. Based upon that witnessed testing, William Hackett states that the SS-L5 type lever hoist can be safely used over a 21-day single, and a 31-day multi-immersion period, subject to the hoist being inspected and maintained according to the manufacturer’s instructions using the OEM spare parts.Since these trials were completed William Hackett has continued to develop its lever hoist range and the scope of field data. The company is now working with some of the largest global subsea operators, one of which has successfully used the SS-L5 lever hoist in multiimmersion condition up to 12 times over a 60-day period. The hoist is now supplied with a warranty that the hoist can be used for multi-immersions.