Pendulum-spring base

Kahlid (2010) the novel pendulum spring base isolation element, an innovative sliding element to resist minor dynamic loads and a TLCGD to dissipate vibrational energy during the strong motion phase of an earthquake. 

But around 1875 Filippo Cecchi (1822—1877) built what it is now considered the first seismograph. However at the time it passed quite unnoticed. Unlike any of the instruments discussed up to this point, the Cecchi seismograph was expected to record the relative motion of a pendulum with respect to the Earth as a function of time. It was based in the inertia principle, and as described by Dewey and Byerly (1969), two common pendulums were used to record horizontal vibrations, each one oscillating in a unique direction and placed perpendicular to each other. Their free period was 1 Hz and the ground motion was magnified three times by a thread-and-pulley apparatus. A mass held on a spiral spring, as shown in Fig. 1, was used for the recording of the vertical motion. A device... 

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