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All posts for the tag “Washers”

Matching washers and bolts of different materials

First published in Bolted #2 2017.

Q: Can I use Nord-Lock stainless steel washers with steel bolts?

A: You can, as there is no difference in thread pitch between steel and stainless steel bolts. However, it is always best to use the same material for all parts of the joint. If you use a stainless steel washer together with high-strength fasteners of grade 10.9 or 12.9, you might deform the washers. These are only surface-hardened, and with a very high pre-load, the softer inside might incur “plastic deformation”. Steel bolts of grade 8.8 or lower might work in many applications, since the mechanical strength of grade 8.8 is similar to the one for stainless steel washers.

Another important aspect to consider when designing a bolted joint, including stainless steel washers and steel bolts, is corrosion, especially so-called galvanic corrosion, which may reduce the product life dramatically. Galvanic corrosion damage is induced when two dissimilar materials are coupled in an electrolyte. When a galvanic couple forms, one of the metals becomes the anode and corrodes faster than it would by itself. The other material becomes the cathode and corrodes slower than it would alone. Nord-Lock steel washers with Delta Protekt coating use the principle of controlled galvanic corrosion. Zinc material in this coating protects the cathode (the washer steel material).

 

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Focus on security in windy and vibrating environment

23 August 2017
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Text: Alastair Macduff

photo: Akkadia, 06photo

First published in Bolted #1 2017.

THE CHALLENGE
Dutch company Akkadia manufactures specialist CCTV systems for demanding situations in various industries. Its cameras can be found everywhere, from offshore, to polar regions and deserts.

Since 2010, Akkadia has had a contract with the Dutch Ministry of Infrastructure and the Environment (IenM), providing CCTV technology in tunnels throughout the Netherlands. Tunnel cameras must be particularly durable, as the vehicles that constantly pass close by create huge wind pressure. Standard security cameras normally don’t last more than a year and a half.

THE SOLUTION
Akkadia developed a specific camera for tunnels – the PTZ – as a stainless steel, vibration-resistant application, built to last more than ten years. To create and maintain such robust technology requires a high-quality locking solution.

The IenM were keen to use its usual self-locking nuts, but Akkadia were already employing a product that would ensure the ability of its cameras to provide long-term, trouble-free traffic surveillance.

Akkadia had entered into partnership with Nord-Lock and fit its washers in the CCTV camera technology. The IenM was subsequently won over by convincing evidence presented by Akkadia about the quality of the Nord-Lock washers, including test reports from TÜV in Germany. The PTZ tunnel camera utilises NL6 and NL8 steel and stainless steel washers on the inside, and NL10 stainless steel washers on the mounting and base.

THE RESULT

All moving parts and internal connections on Akkadia CCTV systems are secured by Nord-Lock washers; from the housings to the base plates.

No problems have been reported in the six years that Akkadia has supplied tunnel cameras to the IenM. Akkadia has now manufactured around 800 systems featuring the Nord-Lock solution. Currently, over 400 PTZ tunnel cameras cover two large motorway projects in the Netherlands – the Amsterdam Orbital, and the Maastricht motorway near the Belgian border.

The success of Akkadia’s tunnel cameras highlights the importance of total cost of ownership. In thinking long term, the IenM has saved money on the cost of maintenance and replacing broken cameras.

Nord-Lock Group keeps the railway industry on track

First published in Bolted #1 2017.

Starting with ROLLING STOCK some 20 years ago, Nord-Lock wedge-locking washers are now found in all safety-related areas of the railway industry, such as bogies, coupling devices, brake systems, rail dampers, housing, and many more.

Nord-Lock washers ensure the functionality of bolted joints, even at the highest levels of vibration caused by rail traffic. One example is in railway switches, highly complex structures that must be used as long as possible with minimal maintenance, while exposed to the elements and to considerable stress.

Nord-Lock steel construction washers (NLSC) help railway companies avoid operational downtime, thus saving money. When renovating or replacing old bridges, small temporary bridges are assembled on site with a bolt preload of 100 percent to achieve secure bolted joints. However, these bolt connections can only be used once. Using Nord-Lock washers, the preload can be reduced.

Overhead line masts and signal masts must cope with severe dynamic loads caused by passing trains. Given the large number of masts, reliable bolt connections are crucial to reducing maintenance costs. With their special geometry, Nord-Lock X-series washers increase security, including on bolted joints with short clamp length, as well as in softer materials.

A recent application for the Nord-Lock X-series is noise-absorbing walls, which cope with extreme vibrations from passing trains. In Germany alone, 3,000 km of noise-absorbing walls are to be installed by 2030. A combination of concrete bolts and X-series washers is used to attach noise-absorbing barriers on existing bridge decks, many of which were not designed for noise barriers.

 

Video: Nord-Lock washers Junker vibration test

Video: Multifunctional Nord-Lock X-series washers

More: Nord-Lock Group solutions in the Railway industry

Washers keep airplanes in the air

First published in Bolted #1 2017.

Look up into the sky in the coastal city of Miri, in north-eastern Sarawak, Malaysia, and you may see Nord-Lock washers in action: inside a radio-controlled aircraft. These hobby airplanes are sold by Byond Horizon, a business that otherwise uses drones to take aerial photos and videos for companies.

“Unlike our drones, these recreational aircraft use gasoline-powered engines,” says Mr. M. Fadzly of Byond Horizon. “These engines cause a vibration problem. Since the frame is made of wood, which is soft, and the engine and its mounting are made of steel, the bolts holding them together can come loose after only four or five flights.”

Fadzly says that it can be difficult to access the plane’s engine, so the loosening is a real problem. A friend of Fadzly’s, however, works at Mayura Engineering and is a supplier of Nord-Lock washers.

“I ordered a box, tried them out, and now I recommend them to all of my customers when we are assembling their airplanes,” says Fadzly. “The Nord-Lock washers never need to be retightened, and they also make sure the engine stays in place. It would be quite dangerous if the engine were to fall out during flight.”

Fadzly not only sells the radio-controlled airplanes, he flies them himself. “I’ve been doing it since 1997,” he says. “It’s a passion, and a fun thing to do on the weekend. It gives you the feeling of flying a real airplane.”

►► Contact us to receive more information about Nord-Lock washers

Converting sea wave motion into energy

CorPower Ocean harvesting energy in the sea

First published in Bolted #1 2017.

ENERGY. With oceans covering more than 70 per cent of the earth’s surface, wave power is potentially a huge untapped source of renewable energy. The problem is that most wave energy converters are too large and costly to be commercially viable. Swedish company CorPower Ocean could have the answer.

The company’s compact Wave Energy Converter works by oscillating in resonance with waves, amplifying their motion and then converting that energy into power. CorPower Ocean founder, cardiologist Stig Lundbäck, invented the initial concept based on the pumping principles of the human heart. In the same way that a heart uses hydraulically stored energy to form back in place, the Wave Energy Converter uses a pneumatic pre-tension system to pull down the buoy after it has been lifted by a wave.

This allows for a relatively small device to harvest a large amount of energy. It is estimated that one buoy, eight metres in diameter, can generate around 250 kilowatts of power. That is enough electricity for around 200 homes.

“If you look at wave energy potential, somewhere between 10 to 20 percent of global electricity consumption could be provided by wave power,” says Patrik Möller, CEO, CorPower Ocean. “It has the potential to become the most competitive source of renewable energy. It offers five times more energy density than wind and ten times more than solar power. Waves have fewer variations and are more predictable than sun and wind, so you know a few days in advance what the energy flow will be.”

Currently, the Wave Energy Converter is undergoing tests with simulated wave loading, while a full-scale demonstration is being set up to begin in 2017. One of the key challenges has been keeping the buoy small and lightweight, while at the same time strong and durable enough to survive the toughest storms at sea.

This has presented a number of fastening challenges. On the mainframe inside the buoy, Cor­Power Ocean has elected to use Superbolt ­tensioners due to their lower torque requirements compared to a single bolt, which makes assembly far more manageable. Superbolt can also guarantee reliability over the buoy’s intended 20-year lifespan. At the base of the buoy, Nord-Lock washers are used, since they can maintain the correct tension over many load cycles over a long period of time.

Renovating Nuremberg’s metro – without affecting the timetable

24 May 2017
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Text: Linda Karlsson

photo: VAG/ Peter Roggenthin, 123rf

Renovating an underground railway system without weeks of construction and chaos caused by delays and diversions was previously unheard of. That is, until a unique concrete bolt emerged in Nuremberg.

First published in Bolted #1 2017.

The people of Nuremberg are proud of their underground system, which is among the most modern in Europe. The city, located in Bavaria, Southern Germany, has the only underground network in Germany where two of the three lines operate automatically, without train drivers. Nuremberg trains travel the equivalent of the circumference of the earth twice each day, carrying more than one hundred million passengers per year.

After 40 years of continuous use, it comes as no surprise that a renovation of the track beds is required to ensure passenger safety. The main beam, also known as a concrete stringer, which attaches the tracks to the tunnel floor, has simply sustained damage in too many places.

This is a daunting issue for the provider of the Nuremberg metro services, VAG (Verkehrs-Aktiengesellschaft Nürnberg). Normally, metro companies need to completely shut down a track for weeks during the renovation of such concrete stringers. Employing water pressure to remove the concrete, it is a time-consuming and extremely dangerous job, considering the many power lines inside the tunnel. Long delays caused by closed tunnels are costly for the track operators, adversely affecting train traffic and irritating passengers.

Coming to the rescue, a brand new innovation caught VAG’s attention just as they started planning the renovation. Local Nuremberg dowel and concrete bolt manufacturer TOGE Dübel won a railway innovation award for a new concept that enhances the sustainability of existing concrete bridges. Present in the audience, VAG representatives were intrigued and had the idea of trying the concept for the first time in an underground rail environment. Currently, work is under way at the first three stations: Bärenschanze, Gostenhof and Maximilianstrasse. Work on the second largest station in the network, the “Plärrer”, with 98,000 passengers daily, is planned for 2017.

Instead of complete reconstruction, concrete bolts measuring 36 centimetres and weighing 1 kilo are utilised as load-bearing components to improve the life span of the overall track bed construction. The bolts are fitted with a patented special thread that cuts into the borehole wall upon application. The force of the bolt is mechanically transferred to the anchor base and the concrete is fixed in place.

“Completely removing a concrete stringer and installing a new one could never be accomplished without service disruption,” says Waldemar Gunkel, Technical Director of TOGE and one of the two inventors of the new generation of concrete bolts.

“In Nuremberg, however, our system is only being installed between the hours of 23.00 and 04.00. By the morning, everything is running ­normally.”

During these working hours, only one track is shut down and trains are redirected via a single track, while the porous areas of concrete on each stringer are chipped away and replaced. Finally, the stringers are fixed into the ground utilising the concrete bolts. Since the bolts need to be drilled into the concrete, there is a risk of inclination as the drilling machine might not be positioned at an exact 90-degree angle. That’s why all concrete bolts that are being used in this first project are secured by Nord-Lock X-series ­washers. Their conical shape can compensate for the inclination, while the wedge effect prevents spontaneous bolt loosening due to vibration.

The Nord-Lock connection came via Deutsche Bahn – Germany’s national railway operator – where Nord-Lock original wedge-locking technology has long been prescribed as the standard.

Jochen Süssenbach, Nord-Lock ­Project Account Manager, sees great potential in this new approach to metro renovation. “We’re looking at a huge renovation of the tunnels that virtually doesn’t affect the timetable at all”, he says. “In terms of costs, it’s also a solution that beats any ­conventional method.”

So far, the renovation is running as planned. The first construction phase has even been completed a week ahead of schedule and the total time for construction carried out at all three metro stations will last six weeks instead of several months, which could have been the case with the previous method.

The concrete bolts themselves are designed to last for 50 years. No concrete will last that long, but further renovations will not be necessary for decades.

Describing TOGE’s Innovation Award-winning solution, Bavarian Interior and Transport Minister Joachim Herrmann said the following: “We have our fingers right on the pulse.” He hinted at the billion-­dollar losses that Germany faces due to the poor condition of some 120,000 ­highway bridges and 30,000 railway bridges.

THE UNDERGROUND RAIL SYSTEMS are in a similar state. Just as in Nuremberg, most metro networks in Germany, as well as in the rest of Europe, were established in the 1970s. Gunkel thinks TOGE has found an important application for its concrete bolt: “This project gives us the boost to further drive our product development forward.”

Facts: The Nord-Lock Solution
Client: TOGE Dübel GmbH & Co.KG.
End customer: Metro services provider, Verkehrs-Aktiengesellschaft Nürnberg (VAG).
Location: Nuremberg, Germany.
Project: Renovating concrete stringers under metro tracks without affecting traffic.
Solution: Using concrete bolts with a patented special thread to reinforce the existing structure.
Nord-Lock Product: X-series multifunctional wedge-locking washers with enlarged outer diameter (NLX24sp)
Benefits gained:

  • Reliability in different environments.
  • Safety under any dynamic load vibrations caused by trains.
  • Excellent partnership in which problems are solved quickly.

Customized washers keep KTM in the race

26 April 2017
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Text: Linda Karlsson

photo: KTM

First published in Bolted #1 2017.

Customer: KTM Sportmotorcycle AG
Production: >160,000 motorcycles ANNUALLY (2015)
Number of world titles: 270
Company size: 2,900 employees, one billion Euro in revenue
Strongest motorcycle: KTM 1290 SUPER DUKE R, aka “The Beast” (177 HP, 1,301 cc, 144 Nm, 189 kilos)
Nord-Lock products: Nord-Lock washers for M6, M8, and a customized washer
Number of models: 45

Pick any of the world’s most exciting motor races and you will find the orange motorcycles by KTM, Europe’s largest manufacturer, among the top contenders.

Located in Mattighofen, Austria, close to both motorsport-crazy Italy and R&D stronghold Germany, KTM mixes influences from both countries with its own “never give up” attitude. After failing to cross the Dakar finishing line ten times, KTM turned failure into a winning streak that has lasted since 2001.

KTM is the only manufacturer that bolts the gearshift lever axially instead of clamping it, making it easier to access with tools. However, the bolt that attaches the conic gearshift lever to the shifter shaft was a weak spot on early pre-series bikes. Heavy washers combined with glue couldn’t prevent loss of preload during some of the most extreme jumps, where the riders land with their foot on the gearshift lever. The whole lever would come loose.

Standard Nord-Lock washers were either too large or too thick to solve the issue. However, Nord-Lock customized an NL6sp washer, with an outer diameter of 16.6 mm instead of 13.5 mm. Two years later, KTM hasn’t seen one single case of gear-lever bolt failure.

Irish Rail safely secured with Nord-Lock washers

Safety is everything for the Irish Rail. When they noticed that the bolts on their axle boxes were loosening due to vibration, they decided to replace the locking-wire mechanism on the wheel sets with Nord-Lock washers.

“Since the introduction of the Nord-Lock washers we have not had one instance of a bolt coming loose which give us a lot of comfort from a safety point of view”, says Conor Doyle, Senior Fleet Technical Support at Irish Rail.

Two years on since the first installation of Nord-Lock washers and Irish Rail has been more than satisfied with the outcome.

Watch the video of Irish Rail sharing their experience of using the Nord-Lock washers:

Learn more: Advantages of Nord-Lock washers
Learn more: Nord-Lock Group solutions in the Railway industry
Watch now: ActSafe trusts the proven quality of Nord-Lock washers