Earthquake detector

An earthquake detector for detecting earthquakes comprising, in combination:

• a planar rectangular platform fixedly coupleable to a recipient surface for receiving vibrations generated as a result of an earthquake;
• a rigid box-shaped housing having an open front, a bottom wall coupled to the platform, a back wall, and a pair of opposed and perforated side walls that are coupled to the top wall, bottom wall, and back wall;
• a frame disposed within the housing, the frame having a central axis, an axially aligned planar rectangular horizontal rigid bottom shelf fixedly coupled between the side walls of the housing, an axially aligned planar rectangular horizontal rigid intermediate shelf located above and coupled to the bottom shelf, and an axially aligned planar rectangular horizontal rigid top shelf located above and coupled to the intermediate shelf, and wherein the bottom shelf has a rectangular axial bore disposed therethrough, the intermediate shelf has a circular axial bore disposed therethrough and a dimension smaller than that of the bottom shelf, and the top shelf has a dimension smaller than that of the intermediate shelf, and wherein the positioning of the shelves defines a generally pyramidic arrangement,
• alarm means disposed within the housing at a location above the frame for sounding an alarm when vibrated at a level that exceeds about 3.0 on the Richter scale;
• spring means coupled between the frame and the alarm means for transferring vibrations to the alarm means when the platform and frame are shaken;
• and
• a rigid counterweight disposed within the housing for damping frame vibration, the counterweight having an upper end coupled to the top shelf, a central shaft portion extended downward through the bores of the shelves, a bumper coupled to the shaft portion at a location between the bottom shelf and the intermediate shelf, and a lower end with a bob secured thereto.