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Feurst earns users’ trust in heavy-duty operations

We talk about Feurst in the french magazine “Mines et Carrières”…

“Feurst has developed the Turnkey range of ground engaging tools with hammerless fitting. It includes full equipment (teeth, adapters, complete range of shrouds) designed for use on excavator buckets of 30 to 400 tons. The Malavaux quarry, in Cusset in the Allier department, has been using these tools since they were marketed. They are fitted to the two excavator buckets. The operator appreciates the safety of maintenance operations and the practical assembly.

The Malavaux quarry straddles the towns of Cusset and Molles, in the foothills of the Bourbonnaise mountains (Allier), in the Rhône-Alpes region. Opened in 1913 when the railway line was tunnelled, it produces high-quality materials from a very hard and abrasive rhyolitic tuf. Its resistance makes it a highly sought-after road construction material for surface courses and bituminous mixes, and for high-speed railway lines.

The 91-hectare site is operated by Granulats Bourgogne Auvergne (GBA) in which LafargeHolcim has a 70% share and Eurovia a 30% share. It has a prefectoral authorisation to operate until 2034 and produce a maximum of 1.4 Mt per year. But current production (900,000 t) leaves the operator with an estimated reserve of over than half a century.

No need to use the hammer to change teeth

Quarrying is carried out on 11 faces including uncovered areas, with blasts carried out once or twice a week, producing 6,000 to 8,000 m3 per blast. The crude run material is 0/1,000 collected with a Hitachi ZX 870 LCR-5B excavator. This excavator loads three to four dumpers of 40 tons in 5 goes to convey the run material to the primary hopper at an average rate of 450 t/hour. The excavator is fitted with an ACB Morin 5,000-litre bucket that was delivered at the same time as the excavator, two and a half years ago. The second bucket is 6 years older and is used when the first one is being refitted, but its capacity is 1 m3 less than the first bucket. These two buckets with semi-delta blades are fitted with five Feurst Turnkey range assemblies intended for 30 to 400 ton-excavators: teeth, teeth-holders, inter-teeth, bucket base shrouds, chocky bars and wear buttons.

Previously, the operator used assemblies from one of Feust’s older ranges called Sticky. The parts – adapter (tooth-holder), tooth pin and tooth – were locked in place using an elastic capacity resin. But the quarry’s mobile equipment mechanic – Jean-Luc Bourgeois – says that every time they had to change the teeth, they had to “hit very hard with a hammer to remove the pin stuck in the resin. We then had to remove the hardened resin to install the new tooth, put back the pin and reinsert the resin”. The operation mobilised one person for 1 hour to change five teeth.

Feurst responded to operators’ desire for less restrictive technology by imagining a solution that was faster to assemble and that did not require a hammer or resin. “Feurst developed Turnkey assemblies in collaboration with quarry operators, taking account of their requirements and their remarks on existing ranges, while looking at the products available on the market” says Thierry Viallet, a sales representative at Feurst.

Reducing movements on the adapter.

The study carried out by Feurst led to the drafting of specifications in which two important points were highlighted: the insertion (i.e. the shape of the nose and the shape of the housing) and locking of the tooth.

The nose of the tooth-holder, on which the tooth is placed, was designed with multiple diagonal and flat facets, to withstand forces by reducing the action-effects on the tooth’s locking system. Olivier Falcoz, the technical manager at Feurst, explains the principle behind the system: “when a tooth is properly positioned on the bearing surface of the nose, the potential movement of the adapter is reduced. This stabilisation process reduces the movement of the tooth on its support once it is locked in place, and this helps reduce the wear of the adapter while increasing the life of the bucket“. Feurst uses double pin geometry with tapered bearing surfaces. The wings, located behind the nose, bear the efforts and limit the vertical movement of the teeth on the teeth-holders.

Olivier Falcoz tells us that “the pressure placed on the teeth in the adapters via locking devices compensates for any looseness that occurs during use”.

The Turnkey range in a nutshell

. Products in this range should be adapted to suit materials and machines used (excavator or loader).

. Wear ratio of over 70%.

. Adapters remain intact after 1,000 hours of use.

. Average life of teeth in severe conditions – 300 hours.

. The locking device can be reused at least twice.

. It takes 45 seconds to remove a tooth in real conditions.

. Turnkey products are available for mining and quarrying for 50-140 mm blades.

The tooth locking system case

The Turnkey solution includes the tooth, adapter and wear cap covering the adapter. The casing or silent-block, as it is called, containing the cast locking device, is inserted into the the adapter. This horizontal locking device has a rotating eccentric system designed to compensate for any looseness between the tooth and the adapter. So when the tooth is mounted, the locking device is turned 180° and this rotates a metal part inside the casing which in turn shifts the axis of the locking system backwards, in such a way as to pull the tooth onto the adapter. “The locking system prevents wear parts from coming away from their supports. They are under maximum compression. In this way, Feurst adds an additional feature that makes the locking device apply a restraining force from the tooth onto the adapter in order to obtain a well secured assembly” says Thierry Viallet.

By keeping the tooth in constant contact with its support, the life of the adapter is extended and therefore, the life of the bucket is also extended.  At the Malavaux quarry, the locking device is used for two, or even three, sets of teeth. Therefore, as advised by Feurst, it should be replaced as a preventive measure.

Disassembling and reassembling teeth in 30 minutes

At the Malavaux quarry, it takes half as long to disassemble and reassemble Turnkey teeth, i.e. only half an hour to replace 5 teeth, and carefully remove any dust that has become cemented to the teeth-holder due to the heat produced when loading materials. The operation is safer for the person doing the job and as no hammers are used, there are fewer risks. Anthony Guillain, operations manager at GBA recognises this: “Working conditions have improved because we no longer use a hammer to remove the locking device on teeth that were difficult to access.”

He also points out that it takes less than 2 minutes to remove and remount the tooth locked onto its support, if only this operation is being done.

The different stages involved in changing a tooth are as follows: 1. remove the side caps that protect the locking system from dust using a pry bar designed by Feurst, and which give direct access to the locking device square (protected from materials); 2. unlock the locking device pin with the tool or a ratchet wrench by turning 180° (a loud clack confirms the operation); 3. eject the locking device with the same tool; 4. remove the tooth and the protective cap; 5. remove the locking device case with the removal tool; 6. clean the adapter, the wear cap dovetails and the passage for the locking device case (when assembling teeth, Feurst requires you to insert a new case), then install the new tooth.

Reinforced, long self-sharpening teeth

Teeth can be changed near the face of the quarry if no heavy work needs to be carried out at the workshop.

The quarry uses the 133 sized tooth model which is self-sharpening, penetrating and long (PRR). A Turnkey tooth’s wear ratio is over 70% which means that it is possible to use more than 70% of the total weight of the tooth. Of the 37 kg of a new tooth, there only remains approximately 11 kg when the time comes to change it.

After 100 hours of use, the teeth have a wear ratio of almost 50% on Hitachi excavator buckets, and do not move on the adapters. According to the operator, they reach a wear ratio of 100% after 230 hours of use. Up until now, three sets of teeth have been used on this bucket.

When they are half worn down, they retain a sharp profile with tear-shaped hollows that enable the bucket to penetrate the deposits easily, says Olivier Falcoz: “Turnkey teeth are self-sharpening with a hollowed-out shape that allows them to retain their penetrating qualities throughout their service life. The aim is to ensure that the tooth does not become a stump at the end of its life. This shape is chosen because it corresponds to the work to be done, and so that the teeth wear out in a regular manner.”

The operator, and particularly the driver, know when it is necessary to change the teeth. During loading operations, drivers can tell when the teeth are worn-out because they have to literally “pull with their arms” to make the bucket penetrate the heap they are loading. Excavator drivers feel this and dislike the bumps that shake the cab.

Turnkey teeth can be inter-changed, particularly those on the end, when a wear ratio of 50% is reached. The teeth on the end are placed in the centre and those in the centre are placed on the end so that the wear is even when the teeth are next changed.

But the quarry’s mobile equipment mechanic does not inter-change any teeth. He prefers replacing the worn teeth with other less worn teeth.

Feurst in the upper-end of the market

Feurst has been designing and manufacturing bucket teeth and teeth-holders for 25 years. These products are intended for production equipment (excavators and loaders) of 30-400 tonnes.

The company was set up in 1992, in Feurs in the department of La Loire. It is a subsidiary of the Safe Group (sales of €250M), the world’s leading manufacturer of cast-steel components used in the nuclear and railway industry.

Positioned in the upper-end of the market, Feurst manufactures all its products in France and 50% of its teeth and adapters are intended for the export market, i.e. Australia, Italy, Russia and Canada.

3,000 tonnes of teeth are manufactured each year.

The Turnkey inter-teeth shields are the most recent additions to the Turnkey range of products and are “hammerless” (no hammer is needed to install them).

Promoting Made-in-France products

Feurst designs and manufactures its ground-engaging tools at its plant in Feurs, in the department of La Loire. The design of the Turnkey teeth stems from the know-how of the manufacturer that constantly seeks to make improvements. These improvements focus on making the buckets easy to load, making the work of excavator drivers more comfortable and making adapters more durable.

At Feurst, there is no secret about the fact that operators appreciate products that are manufactured in France.

We pay a lot of attention to the composition of the teeth and the treatment they undergo” says Thierry Viallet. “To produce the quality required for wear parts, Feurst has developed production methods that reduce impurities in the liquid steel. The cast parts are subjected to a heat treatment process, then a hardening process that freezes the structure, and then a tempering process that relieves the stress.

Low-alloyed steels are used for Turnkey teeth (carbon, chrome, nickel). Their composition is adapted to the wear part in order to obtain a hardness of over 500 HB in the core of the tooth. In terms of resilience, they have an impact resistance of 20 joules. Adapters have different characteristics, i.e. a lower hardness of 380-420 HB and an impact resistance of 25 joules. The composition of adapters is different from that of teeth due to the weldability of adapters.

The rubber cases in the Turnkey range are also produced in France by a manufacturer in the same region.

Improving a bucket’s service life by 50%

By offering this new Turnkey range, Feurst estimates it can extend the service life of buckets by 50%. The company bases this estimate on the fact that the tooth remains immobile and tightly fitted to the adapter, meaning there is less vibration and less impact. “When a 555 HB tooth moves around on its 420 HB support, it wears the nose of the adapter. The phenomenon worsens over time and may lead to the housing of the tooth breaking, a tooth falling out and even the locking system being exposed to further stress” says Florian Bénetière. This is an essential element of Feurst’s sets of adapters and teeth.

Adapters in this range have a service life of 2,500 hours. But the spectrum studied is much broader because in one case the service life reached 20,000 hours, indicates Feurst. It all depends on the working conditions and the tooth. As for the locking system, it can be used with up to 3 sets of successive teeth, even if the working conditions are considered difficult, as is the case at the Malavaux quarry where the materials are hard, abrasive and compact when they are in heaps.

2,500 hours is also the threshold after which the operator refits one of its two buckets. It takes advantage of this operation to change all the shrouds and also the blade.

Even if Feurst positions its offering in the upper-end of the ground-engaging tools market, it is important to take the full service life of a bucket into account when looking at the cost of the shrouds. In Cusset, when the previous excavator had to be changed after 19,000 hours of service, the original bucket was still in place, thanks to the regular refitting.”

Jean-Pierre Le Port.

New Hammerless Turnkey®

turnkey® teeth in a few numbers…

Wear ratio : + 70%

Teeth average lifetime in most severe conditions : 300 hours

Locking devices reusable : x2

Removal time in real conditions : 45 secondes

Intact adapters after 1000 hours

Your full mining range for blades 70-140mm

Find out our Turnkey® teeth and adapters catalog

 

check out in this video how to install and disassemble turnkey® teeth !

turnkey® SHrouds : a very easy assembly and disasssembly !

Blade and lip shrouds

one weld base

180 degrees hammerless locking device

……. of blade shroud offering a very high protection

a weld base fully protected by the removal shroud

Find out our catalog about Turnkey® bucket shrouds

 

 

Contact

1 Boulevard de la Boissonnette, 42110 Feurs - France
+33 4 77 27 40 63
sales@safe-feurst.fr

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