first surface 9211 is opposite to the second surface 9212 an example of mounting the seismic energy dissipation device to a steel frame 1 is shown in fig5 the steel frame 1 comprises a beam 11 and two columns 12 the first plate 5 is connected to the beam 11 and the base frame 9 is connected to the columns 12 through two inclined struts 3 fig6 shows the assembly of the seismic energy dissipation device according to fig5 the cylinders 7 can be put directly into the notches 921 without touching the third surfaces 9213 thereof i e there is a space between the third surface 9213 and the cylinder 7 in this manner the assembly method of the present invention is easier than the assembly of the prior art tadas device because it does not require such rigid precision in distances between the cylinders 7 the circular washers 8 fill the space between the walls 92 and the narrower ends 62 of the tapered plates 6 to prevent undesirable free play after assembly as shown in fig5 and 7 when lateral forces 21 are applied to the steel frame 1 the tapered plates 6 deform and no eventual collisions between.