In this case study, HARDLOCK® nut was chosen over double nutting for installation in seismic isolated building dampers on the anchor bolt. Fasteners used to hold down the rubber components in the damper are much weaker than metal joints meaning they must be fastened with much less torque (clamp force) than a regular fastener. Double nut is a solution which can achieve good locking but can lead to risks of loosening in the case of bad installation. HARDLOCK® is easy to install with no risks for installation problems. In Japan on average, there are 153 earthquakes each year over magnitude 6.0. To keep buildings from shaking such seismic isolators are required. HARDLOCK® is used in many seismic isolators across Japan to ensure safety. In Japan they have the phrase “Sonae areba urei nashi” which means if you are well prepared there is nothing to fear. This phrase represents well the use of HARDLOCK® nut because you don`t know whether your current loosening preventions solution is right until there is an Earthquake.
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