14.05.08
The NORD-LOCK system for safer rail design
It is vital that bolted joints holding subassemblies together remain secure. Bolts need to be easily removable during maintenance, but resist loosening when exposed to vibration and dynamic loads
NORD-LOCK has developed a securing system that makes the bolt self-locking. The principle is based on a pair of washers that provide a wedge-locking action meeting DIN 25 201, a unique method using tension instead of friction. On one side the washers have cams with a rise greater than the thread angle of the bolt, and on the opposite side there are radial teeth.
The washers come pre-assembled as a pair cam face to cam face. When the bolt and/or nut is tightened, the teeth grip and seat into the mating surfaces. The washers are locked in place, allowing movement only across the face of the cams. Any loosening movement of the bolt/nut is blocked by the wedge effect of the cams. The increase of tension makes the bolt/nut self-locking.
For machinery requiring regular service and maintenance, NORD-LOCK is the optimum solution. Bolted joints secured with NORD-LOCK are easily assembled and disassembled and no special tools or fasteners are needed. Since the NORD-LOCK bolt securing system uses tension instead of friction to secure bolted joints, the locking function is not affected by lubrication. The use of a good lubricant is recommended in order to reduce friction, minimize clamp load deviation and to protect against corrosion.
All NORD-LOCK washers are produced in compliance with the European directives on RoHS and ELV. Washers are available in steel with zinc flake coating for bolts from M3 to M130 and in stainless steel from M3 up to M80.
Ultra Dynamics in the U K manufactures rail retarder systems used in marshalling yards worldwide. The company has chosen NORD-LOCK washers to secure all critical fasteners since the retarders are constantly exposed to high/low frequency vibrations, shock loads, pressure loads and daily temperature changes.
NORD-LOCK washers have successfully solved loosening problems on rails, switches, signal systems, chassis and passenger compartments throughout Europe and the U.S. The system makes assembly easy and provides maximum safety.
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