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bolt securing

All posts for the tag “Nord-Lock”

Cheaper but better solution for tractors with washers

4 January 2018
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Text: Ekin Calisir

photo: Hattat

First published in Bolted #2 2017.

CUSTOMER: HATTAT TRAKTÖR
HORSE POWER RANGE: 50–102
LOCATION: CERKEZKOY, TEKIRDAG, TURKEY
NORD-LOCK PRODUCTS: NORD-LOCK WASHERS NL8 AND NL10
PRODUCTS: TRACTORS FOR AGRICULTURAL APPLICATIONS

A producer of agricultural vehicles for close to 20 years, Turkish company Hattat Traktör knows that, when the going gets tough, it is the durability and reliability of their products that save the day. The company’s customers often deal with rugged terrain for long periods, racing against time to maintain productivity, so their machinery must be able to withstand tough conditions such as handling vibration.

Early in 2017, when Hattat Traktör was testing a new tractor model, they realized that the joints on the air compressor–engine connection bracket were loosening because of vibration. According to the company’s vibration analysis, this problem could have been solved by a costly and time-consuming change in the bracket design, or by replacing the loosening bolts with stronger ones.

At this point, the company’s research and development department started looking for new components for their design. After days of research and evaluation, they found Nord-Lock washers, which had the potential to save them from a more costly solution.

During the tests, Nord-Lock washers proved that they could solve the problem, and this solution was much cheaper than having to change the bracket design. With Nord-Lock washers in place, the vibration caused no more loosening, to the relief of Hattat Traktör customers, who can now rely on their red tractors, even under the harshest conditions.

No more loose screws on giant quay cranes

29 November 2017
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Text: Roxana Ortiz

photo: Paceco

First published in Bolted #2 2017.

CUSTOMER: PACECO ESPAÑA S.A
PRODUCTS: QUAY CRANES, YARD CRANES, SERVICES AND SYSTEMS FOR CONTAINER HANDLING
ESTABLISHED: 1967
SHAREHOLDERS: MITSUI GROUP AND URSSA, S. COOP.
NORD-LOCK PRODUCT: NORD-LOCK 20 / NL20

Offering cranes, services and systems to the container-handling industry, engineering company Paceco España (Spain) must adjust to its customers’ needs. As ships get bigger, quay and yard cranes must increase height and reach, while also becoming more efficient. Today, Paceco España can load and offload ships from 25 container lines. The company currently produces one of the largest and most efficient cranes on the market, the Portainer Malaccamax, which maximally offers a 72.5-metre outreach, a 52.5-metre clearance under spreader, and a 30.48-metre rail span.

Paceco España first connected with Nord-Lock in 2009, when there was a problem with one of the company’s quay cranes. The crane, with a 65-ton load capacity, had problems with the fixing of the gantry reducers – the gearboxes that move the quay crane along the dock. During operation, the fixing screws vibrated loose.

During their problem analyses, Paceco España’s engineers connected with Nord-Lock and when it presented a solution, Paceco España was pleasantly surprised. “We have been using their washers since 2009, and haven’t had any problems with bolted connections being subject to vibrations since then,” says engineer Pelayo Bobes. “With Nord-Lock washers, we have been able to provide total customer satisfaction and in turn saved both money and time.”

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).

 

ASK THE EXPERTS
Do you have a question about bolt securing?
Put the Nord-Lock experts to the test.
Email your questions about bolt securing to
experts@nord-lock.com

New issue of Bolted magazine out now!

The 2017 September issue of Bolted magazine is available now! As with every issue we have filled the magazine with interesting cases and insights from the world of bolting.

In this edition, our theme article focus on lug wear which is a common issue for pivot joints. But why does it occur, what solutions exist and do they solve the root cause of the problem?

You will find out more about Expander System in our customer case, where we visited Danish company Viggo Benz who delivers solutions and equipment for crushing, demolition and sorting.

Also, see how Nord-Lock washers secure containers that transport radioactive substances, where there is no room for equipment failure.

Last but not least, don’t miss out on how and why we now offer lifetime warranty throughout our product range.

Bolted magazine is available in 9 languages – download them now:
English
German
French
Swedish
Finnish
Japanese
Chinese
Korean
Spanish

Want to receive your complimentary copy of the Bolted magazine? Subscribe here now!

The Experts: Improving fatigue resistance

First published in Bolted #2 2015.

A: The fatigue capacity of a bolted joint is very small, as compared to its static capacity. To improve fatigue resistance, designers can increase the thread capacity and decrease the alternating stresses at the threads.

To increase the thread capacity, it is recommended to use a rolled thread instead of a cutting process. To increase the bolted joint capacity, utilize multiple smaller fasteners instead of a single larger fastener.

The capacity is also increased by using an improved connector, such as a Superbolt MJT (Multi-Jackbolt Fastener) or Flexnut, which improves the load distribution in the threads and adds elasticity to the bolted joint.

The best way to improve fatigue resistance is to reduce the alternating stresses at the threads. There are three main ways of doing this: Assembly design, assembly tightening, and assembly security.

The assembly design process provides an opportunity for improvement of the load distribution on bolted joints and to reduce the level of external stresses supported by each joint. To facilitate that, keep these principals in mind:

1. Use the highest possible preload
2. Minimize the bolt to load eccentricity
3. Use the largest possible contact surfaces
4. Use the largest possible clamping lengths
5. In most cases, use a preload higher than the working load

Other assembly design options include the use of necked-down studs or bolts, and the use of elastic washers, which counter the effects of relaxation, creeping, and thermal differential elongation.

With regard to assembly tightening, achieving the necessary preload is the main factor in reducing alternating stresses. It is recommended to use calibrated tools with high accuracy. It is also recommended to use a proper lubricant to achieve preload accuracy, and to reduce the risk of seizing. A suitable tightening sequence should be used to mitigate the risk of un-evenly loaded bolts and to ensure overall bolted joint integrity.

Regarding assembly security, it is recommended to secure the bolted joint against loss of preload. Further, secure the assembly against environmental effects, such as corrosion that could initiate a fatigue crack. This may be done through the selection of suitable materials and/or coatings for parts and fasteners.

 

ASK THE EXPERTS
Do you have a question about bolt securing?
Put the Nord-Lock experts to the test.
Email your questions about bolt securing to
experts@nord-lock.com

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.”

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