This product is registered by Azumaneji Co., Ltd..
About This Product
■Loosening prevention washer (NORD-LOCK®)
NORD-LOCK® washers use tension rather than friction to secure bolts. The system consists of a two-piece washer with a cam surface on one side and a radial rib surface on the other side.
When the screw is tightened, the rib bites into the fastened object and the bearing surface of the bolt/nut and fixes it. Therefore, when a bolt or nut tries to rotate due to loosening due to vibration or shock, only the cam surface will move, but the cam angle (α) is designed to be larger than the screw lead angle (β). Therefore, the cam cannot be easily overcome. In this way, the cam surfaces create a wedge effect, which prevents the bolt from loosening due to rotation.
■Junker vibration test
The Junker vibration test, based on the German industrial standard DIN 65151, is a vibration test to check for loose bolt connections. In the test, the fastened object is vibrated to cause slippage, and the tightening force (axial force) is continuously measured while applying force in the direction perpendicular to the axis of the bolt.
The results of the Junker vibration test are shown in the figure. With Nord-Lock washers, there is only a slight decrease in axial force due to initial break-in, and there is almost no loosening over time. When the bolt was released, the axial force of the bolt increased, proving that the cam had a locking effect.
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