A Junker test machine (also known as Junker machine) tests connections according to DIN 65151. We made a movieclip where we run 4 tests using such a Junker testmachine. These tests show the difference between connections using
This movie shows connections under the specific circumstances this Junker test machine tests for, ie extreme vibrations that take place in heavy machinery like trains, harvest machines in agriculture and MRI machines in the health care industry
The chart that appears on the connected laptop shows the force applied by the bolt to the left on the y-axis, the more force the sturdier the bolt is secured. During the tests you see the force deminishing (relaxation), the x-axis shows the time. We use a shortened test to not have the demonstration with the Junker test machine take too long: 10 seconds using a frequency of 40Hz.
The resulting graphs show that for applications with heavy vibration the use of Nord-Lock washers might be advisable. After some initial setting the the force on the connection remains constant. This is because the two Nord-Lock washers are coupled with edged teeth that are slightly steeper than the pitch of the bolt. You need more force (see the end of the movieclip) to turn the nut loose than it applies to the connection. Our sales advisors have a small kit for a manual demo where you can experience this effect yourself. Now you need less connections in your machine!
For more information about Nord-Lock contact our sales advisors. Thank you Leonard for demonstrating the Junker testmachine!