US 5,742,235 A · Vertical, unidirectional seismic switch

Abstract

A switch including a mass suspended above a base by a flat horizontal spring has electric contacts that close in response to the initial shocks of major earthquakes and activates safety devices before the onset of destructive ground motions. The vertical unidirectional seismic switch can be manufactured by micromechanical photolithography and is integrated with electromechanical safety devices to latch cabinets closed, secure movable objects, shut off gas, water, and electric utilities, activate alarms, early warning networks, and related automated response systems. The device is fully self contained, consumes no power until activated, is inexpensive to produce, and impervious to nonearthquake noise in that it is designed to respond specifically to the vertical acceleration and displacement characteristic of the initial shock waves of a major earthquake.

Claims12

Dependent claims

The manufacture of a vertical, unidirectional seismic switch by micromechanical photolithography by;

a) applying a first photosensitive resist on a nonconductive substrate, exposing the resist to light through a pattern of two attachment points, and developing it to expose two attachment points on the substrate;
b) depositing a conductive layer contacting the substrate at the attachment points and burying the first resist layer;
c) applying a second photosensitive resist on the conductive layer, exposing it to a second pattern of the operating elements of the seismic switch consisting of a mass suspended over an electric contact by a flat spring, and developing the second resist to mask the operating elements of the switch;
d) acid etching the conductive layer to remove unwanted material;
e) striping away the first and second photoresist layers to free the operating elements of the seismic switch, allowing them to move in response to earthquake motions.

2 more elements

A vertical, unidirectional seismic switch to detect the initial shocks of major earthquakes and activate earthquake safety devices before the onset of destructive ground motions, comprised of;

a) a base that may be fastened to objects within, or elements of structures in contact with the earth;
b) a mass suspended above the base with a flat horizontal spring connecting the mass and base, so as to decouple the vertical motion of the mass from that of the base allowing the mass to move downward relative to the base, when the whole assembly experiences the upward accelerations and displacements characteristic of the initial shocks of a major earthquake;
c) the inertial mass, spring and damping forces of the assembly being adjusted so as to tune the spectral response of the assembly specifically to the vertical accelerations and displacements characteristic of the initial shocks of major earthquakes;
d) electric contacts on the bottom of the mass and on the base directly below the mass which are normally open and make momentary contact when the assembly experiences the upward vertical threshold accelerations and displacements characteristic of the initial shocks of a major earthquake;
and
e) electric means to connect the contacts on the mass and base to electromechanical earthquake safety devices.

3 more elements

Dependencies are inferred from the claim text.

Vertical, unidirectional seismic switch

Life of this patent

Vertical, unidirectional seismic switch

Life of this patent

Abstract

Claims12