Nord-Lock: Maximum security for bolted joints
About Nord-Lock
Company Overview
Nord-Lock was founded in Sweden in 1982 with the radical vision of developing the world’s most effective bolt locking system. Their challenge was to bring a new product to the market, to continuously improve the design and become the best bolt locking system available. To achieve this, the company has employed the most talented and innovative staff, fostering close teamwork, with an ambition to solve the most demanding joint problems. The outcome – Nord-Lock: the world’s best bolt securing system.
The Nord-Lock production plant is located in Mattmar, near the town of Östersund in Sweden. The company has offices in Benelux, Czech Republic, England, Finland, France, Germany, Japan, Poland, Sweden, and the USA - with worldwide representation via a number of exclusive distributors.
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Products: The Angle That Works
Nord-Lock is a superior bolt securing system that does not use traditional techniques to secure the fastener, and yet still provides a safe locking system for bolted joints even when exposed to severe vibration and dynamic loads.
The Nord-Lock bolt-securing system is comprised of special cam faced washers; in order to facilitate assembly Nord-Lock washers come pre-assembled in pairs (glued). All Nord-Lock washers are ELV and RoHS compliant. Nord-Lock washers are available in steel and stainless steel.
Nord-Lock steel washers are made of EN 1.7182 or equivalent alloy. All Nord-Lock steel washers are through hardened. Steel washers are available with the following coatings:
- Zinc flake coated (Delta Protekt®): NL3 to NL42 (standard sizes) and NL45 to NL130 (upon request). Endure a minimum of 600 hours of salt spray test in accordance with ISO 9227.
- Passivate: NL3 to NL42 (upon request)
Nord-Lock stainless steel washers, A4, are made of EN 1.4404 or equivalent alloy (AISI 316L is the corresponding US standard). All stainless steel washers are surface hardened. Stainless steel washers are available in the following alloys:
- A4 in NL3 to NL42 (standard sizes) and NL45 to NL80 (upon request).
Nord-Lock also offers stainless steel washers in special alloys (in limited sizes, upon request):
- Nord-Lock 254SMO (EN 1.4547) washers; for salt-water applications.
- Nord-Lock Inconel® / Hastelloy® C-276 (EN 2.4819) washers; for applications in acid environments.
- Nord-Lock Inconel® 718 (EN 2.4668) washers; for high temperature applications.
Nord-Lock washers with enlarged outer diameter (sp) in combination with flanged nuts/ bolts are recommended for use on large/long holes, painted surfaces or soft materials, e.g. aluminium.
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The Locking Function
The Nord-Lock bolt securing system uses geometry to safely lock bolted joints in the most critical applications. Tension makes the bolt self-locking; the key is the difference in angles. Since the cam angle " a " is larger than the thread pitch " ß ", the pair of washers expands more than the corresponding pitch of the thread. Any attempt from the bolt/nut to rotate loose is blocked by the wedge effect of the cams. Nord-Lock washers positively lock the fastener in a joint that is subjected to extreme vibration or dynamic loads.
This unique wedge-locking system offers the following advantages:
- Maximum safety
- Resists loosening caused by vibration and dynamic loads
- Ease of assembly and disassembly
- Locking function is not affected by lubrication
- Positive locking at low and high preload levels
- Controllable preload
- Same temperature characteristics as standard bolt/nut
- Reusable
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The Truth: The Junker Test Principle
For testing and comparing the security of bolted joints, a Junker vibration test meeting DIN 65151 is an excellent method. In a Junker test the bolted joint is subjected to transverse movements while a load cell is continuously measuring the tension.
The diagram displays Nord-Lock’s superior performance. Most of the commonly used locking devices show limited or no holding performance when exposed to vibration. Whereas bolted joints secured with Nord-Lock washers only lose some of the initial preload due to normal settlements between the contact surfaces. Nord-Lock’s unique wedge-locking function is proved by the clear increase in clamp load during untightening.
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Unique Value
The best proof of Nord-Lock is real-life testing. To optimise the design of bolted joints and verify their locking function, many companies take advantage of the customised tests Nord-Lock offers at its in-house test laboratories. Nord-Lock’s dynamic joint testing laboratory includes a complete set up for torque-load and vibration testing with adjustable frequency, amplitude and clamping length. Testing and/or optimising your bolted joints will minimise overall or whole life costs.
- The built-in security of Nord-Lock washers ensures locking of bolted joints. A focus on safety helps avert expensive warranty claims.
- The reliability of Nord-Lock products helps to improve customers’ productivity and profitability.
- Furthermore, quick and easy assembly and dismantling cuts downtime and associated costs, making it the optimum solution for machinery requiring regular maintenance.
We supply samples, free of charge, so that you can test the product on the spot; we can also arrange technical aid from Nord-Lock engineers. Contact us today to order your free samples or to learn how we can assist you in finding your ultimate bolt locking solution.
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Focus on Quality
Nord-Lock’s strong reputation is based on the core values of quality, service and reliability.
Along with safety and security, these have been Nord-Lock’s keywords since the company’s founding. The company’s policy is to develop, produce and market products of a quality that fulfils internal and external demands and customers´ estimated needs, in a cost-effective way.
- Nord-Lock has full traceability and control on all processes.
- Test certificates are provided free of charge on request. Nord-Lock is a proud keeper of the ISO 9001 and ISO 14001 certifcate.
- Nord-Lock washers have been put to the test by several independent authorities, e.g. Technisher Überwachungsverein (TÜV), Deutsches Institut für Bautechnik (DIBT) and Det Norske Veritas (DNV).
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Secured by Nord-Lock: Case Studies
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Engineering With A Bite
Viper Motorcycle Company
Source:
Nordlock Bolted Magazine Issue #2, 2010
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For the past eight years the Viper Motorcycle Company have created unique custom-made Super-Cruiser motorcycles that combine first-class engineering with elegant design. Over 80% of their motorcycles are made from proprietary parts, designed and created by Viper themselves, using the most advanced 21st century technology. Last June Viper released their superbly crafted 2011MY motorcycle as an evolution to their 2009/2010MY line. The new bike is not only a high performing vehicle with Viper’s trademark proprietary parts and new Viper/Ilmor engine, but also beautifully designed with a keen sense of style.
While striving for the highest standards of engineering, Viper decided to implement Nord-Lock washers in eight locations, including turn-signal stalks and brake rotors. By using Nord-Lock with zinc-based plated bolts instead of thread-lock and chrome-plated bolts, Viper avoids chrome buildup and binding, which can damage well-engineered joints and significantly reduce the torque applied.
The Nord-Lock bolt securing system allows for quick and easy torque checking without breaking a thread locking material, which is a huge advantage when servicing and maintaining critical fasteners. No fastener using Nord-Lock has ever lost any clamp load.
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Environmental Policy
The activities at Nord-Lock affect the environment – like all industrial activities do. Nord-Lock believes it is its obligation to reduce the effects on the environment, as far it is ecologically and financially reasonable.
Nord-Lock’s Environmental Management System enables activities to be continually tried against environmental values to ensure that the company prevents pollution, fulfils valid environmental laws and regulations, and steadily reduces the effects on the environment.
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