The Nord-Lock bolt securing system uses tension instead of friction to ensure that joints holding sub-assemblies together remain secure. Bolts on pumps need to be easily removable during maintenance procedures, but must resist the loosening effects of vibrations and dynamic loads. Bolts that are locked conventionally by friction in the thread tend to lose most of their preload through vibrations, while those locked by the tension of this system present a minor loss of preload which is caused mainly by settlement in the thread. Even after moderate tightening, the bolt is safely locked when using Nord-Lock.
It has become increasingly important to have good control of the torque-clamp load relationship when tightening a joint. To optimise the design of the joint and utilise as much of the capacity of each dimension as possible, it is important to know the required tightening torque. Nord-Lock washers, which are installed in pairs, cam face to cam face, have cams on one side, with a greater rise than the pitch of the bolt. When the bolt and/or nut is tightened, the radial teeth on the opposite side grip and seat the mating surfaces. The teeth also lock the washers in place, allowing movement only across the face of the cams. The resulting tension makes the bolt self-locking.
These washers can be used on standard grade, as well as high grade bolts and there is no need for adhesives to lock the stud bolt. This system is designed for use in tapped and counter-bored holes and for larger holes or on soft materials, a flange nut or bolt should be used in combination with Nord-lock washers with a larger outer diameter.
Advantages of this reusable system include maximum safety when locking fasteners, easy assembly and disassembly, positive locking at low or high preload levels and minimum surface marring or scratching. This system, which has the same temperature characteristics as a standard bolt or nut, resists loosening caused by vibration and dynamic loads. The locking function is not lost by lubrication.
A method for testing the security of a bolted joint is the Junker-vibration test where the preload (bolt tension) is measured by a load cell and vibrating motions are generated radically through the bolt.
New generation low power frequency inverters Bearing Man Group T/A BMG
Electrical switching & drive systems & components
New to BMG’s electromechanical range are energy-efficient Synergy PI150 series frequency inverters, which have been designed for efficient use in many applications.
Read more...Motion technology for all types of automation Bearing Man Group T/A BMG
News & events Electrical switching & drive systems & components
BMG has been appointed by The Timken Company as a distributor in southern Africa for the Rollon linear motion guidance system.
Read more...Efficient maintenance counts Bearing Man Group T/A BMG
Shaft power components
BMG’s total plant management solutions encompass a technical advisory service for maintenance programmes that includes correct chain and sprocket selection, which is a critical factor in any power transmission system.
Read more...Optimise your plant assets SKF South Africa
Shaft power components
The SKF Rotating Equipment Performance Centre provides anyone from anywhere with easy access to a comprehensive suite of advanced condition monitoring, analytical and diagnostic solutions.
Read more...Hydraulic pumps deliver high flow, convenience and precision Bearing Man Group T/A BMG
Hydraulic systems & components
BMG’s range of high-performance hydraulic electric Enerpac E-pulse pumps is critical to all 700 bar operating hydraulic systems. These portable E-pulse pumps have intelligent auto-cycle functionality and an efficient power-to-weight ratio to ensure dependable operation and high productivity in challenging industrial applications.
Read more...Advanced solutions for valves Bearing Man Group T/A BMG
Shaft power components
BMG delivers state-of-the-art valve solutions to diverse industries across Africa, in collaboration with InterApp, a global leader in the design and manufacture of high-quality valves.
Read more...Monitoring the health of systems SA Gauge
Editor's Choice Shaft power components
Pressure and temperature gauges are vital instruments in various industries. However, they are susceptible to failures that can compromise their accuracy and reliability. When these gauges fail, the consequences can be severe.
Read more...Cogged raw edge belts SKF South Africa
Shaft power components
SKF’s cogged raw edge belts are ideally suited for essentially any industrial application that runs on ISO wedge and classical V-belt pulleys.
Read more...The torque of the town
Shaft power components
Bolt and Engineering Distributors (B.E.D.) is pleased to announce its new distribution agreement with torque and tensioning company Bolt Torque, which has a comprehensive range of manual, hydraulic, electric and battery bolt torque, and bolt tensioning solutions.
printer friendly version