For which applications are these the weapons of choice?
Shovel heads, drum cutters, pile cutters and riddle buckets are all part of the excavator’s arsenal – but for which applications are these the weapons of choice?
We all know that excavators have buckets on the front. After all, that’s the point, right?
Well, yes, but there are several new technologies to increase the speed and reduce costs of excavating. Some you have probably heard of, if not actually used. Others might be less familiar.
A good place to start investigating different attachments for machines was German Gulf Engineering based in Sharjah. This firm has been going since 1974 and incredibly, at least one Atlas excavator from this date remains in service, though the majority of the fleet are now Hyundai machines of various weights.
“This is to be mounted on a thirty tonner,” said the firm’s plant hire manager, Mr. Menon said, indicating a large bucket with a quick hitch coupler, and a set of tungsten-tipped teeth, “This is for the normal excavation. Generally about 80 per cent of the work in the UAE is normal excavation, because the soil is very sandy.”
Of course, correct bucket selection also makes a big difference to the speed of a job, as well at the amount of diesel used.
Any bucket needs to be the correct one for the job. In any application, the bucket must be able to stand up to the huge break-out forces involved in it.
Buckets come in a wide variety of sized and shapes, but generally they can be put in to two categories: the smaller type for earthmoving, as seen on construction sites and larger buckets found in the quarrying industry.
With extreme earthmoving projects ongoing, such as the anticipated Arabian Canal, these large rock buckets have fount their way onto construction sites. “For the canal, they need huge buckets” said Menon, gesturing towards a scoop roughly the size of a studio flat in Sharjah. “We have an even bigger one, too,” he added, as a giant 50-tonne Hyundai RC-500LC trundles into the yard with an even larger bucket.
However, bigger isn’t always better. When digging specific areas such as tight city workspaces, or narrow gulleys, it is obviously better to have the correct bucket for the job as the amount of fuel saved by not having to double-handle work would be substantial.
The first device to catch our eye is a spiky-looking wheel attached to a machine that had just come back from hire. This is an Erkat drum cutter, and has been developed to eliminate the need for traditional rock breakers when trenching in hard stone.
Users recon that the cutters nearly double the output compared to traditional methods. Menon explained; “There are areas where the soil is too hard and the bucket just scratches, for this you need the drum cutter. It is very fast and safe.”
While drum cutting is only used on a handful of UAE sites at the moment, in other parts of the region it is very popular. “In Oman and Doha is very popular” he said. “We were the first company to use it here, and on several sites including The Waterfront where there is something not totally rock, not totally limestone,” Apparently, the drum cutter ‘simply crunches through’ this type of high-carbide stone.
The old method of demolishing unwanted foundation piles involved jackhammers, saws, and a whole lot of labour. Clearly, this would very quickly become a drain on resources should more than one pile need removing. “One of my specialities is pile cutting. We have cut over a million piles now” Memon said,
“We have a longitude cutter working in Dubai. This one cuts from the inside, outwards. Any pile over 1.4 metres we can’t crush with our machine. For that we use this and auger it from the inside, out. At the moment it is working at the Schumacher Tower in Business Bay.” Larger piles are necessary as buildings get heavier and taller. “At the moment, the standard here is piles 1.8 metres tall, but 2 metres will be common soon” he explained.
Not common in the UAE yet, these buckets with a meshed rear are invaluable for any application where soil or sand needs to be sorted from stone or rubble. They allow brick, concrete, stone, vegetation or any other debris to be separated from soil, and the heavier duty, ribbed back models are suitable for sorting rock or concrete, prior to crushing or screening.
While these buckets are not often seen here, a company new to the region, Fleco Attachments have brought these and others to the region. Andrew Morrison, a regional manager at the company said; “Riddle buckets are ideal for any applications where you want to move the debris, rather than the soil itself.”
The gap between the riddle bars, known as ‘tines’ will depend on the nature of the stone and soil you wish to separate.”
He added these were popular in the demolition industry in the ‘States, as well as closely related attachments such as skeletal rock buckets.
For moving large boulders, or handling rubble on a demolition project, the tool of choice is a grapple, sometimes known as a grabber. Menon said; “This is for stone placing. We have a project coming up, where this grapple will be put on the end of a fifteen metre boom.”
Used for placing stones, the grapple can also be found in the scrap handling and demolition industries. A close relative of the grapple is the pulveriser, which is an evil looking jaw used in demolition, which can literally ‘chew’ its way through brick. Modern developments now allow this attachment to also be used as a rebar cutter. So now you’ve read the scoop, go and choose a bucket.
The most basic method of breaking down piles is to either use hand held breakers or plant-mounted pneumatic breakers. While this method is perhaps the easiest to specify and takes no initial planning, it can produce unacceptable heath and safety risks and causes unnecessary damage particularly to small diameter piles if not very carefully controlled.
Specially designed pile breakers are available in a range of sizes and capability. Hydraulic pile breakers are both available for cast in situ and precast piles.