There are two main reasons why bolted joints fail: spontaneous bolt loosening and slackening. Traditionally, application design has involved trying to figure out which will have the biggest effect on the joint and choosing a solution to handle that one problem. It is a difficult compromise to make, especially when both could cause application failure.
Expand your bolted joint design possibilities with an excellent security option.
Upon tightening the fastener, the washers flatten and the serrations engage the contact surfaces. Since the cam angle (α) is greater than the thread pitch (β), the wedge-locking effect will prevent any rotation of the fastener. Directly after tightening, the joint settles and the fastener sinks into the surface material. The washers immediately deflect and the spring effect (Fs) counteracts the slackening movement of the bolt, thereby preventing loss of preload on the joint.
These multiple functions continuously act on the bolted joint to maintain preload and prevent spontaneous bolt loosening — serving as an effective solution for vibration, dynamic loads, settlement and relaxation.
Below you find a selection of advantages with Nord-Lock multifunctional wedge-locking solution.
The Junker test, according to DIN 65151, is considered the most severe vibration test for bolt connections. The test exposes the joint to transverse movements underneath the bolted head/nut, while continuously measuring the clamping force.
The Junker test shows that Nord-Lock’s wedge-locking function safely secures the bolted connection, which is verified through the clear increase in tension during untightening. The Nord-Lock X-series kept the highest initial tension thanks to its additional spring effect.
Would you like to learn more about the performance of Nord-Lock X-series washers? Contact your nearest representative through Contact us.