SENSOR OF SISMOSFIELD OF THE INVENTIONThe present invention relates to earthquake sensors and earthquake alarms in general.
BACKGROUND OF THE INVENTIONVarious types of earthquake sensors are known in the patent literature. The following North American Patents are believed to represent the state of the art: 4,086,807; 4,262,289 4,297, 690;4,358,757 4, 484, 186 4, 662,225 4, 689, 997 4,764,761; 4,764,762 4, 789, 922 4, 841,288 4,904,943 4,945,347; 4, 978, 948, 4, 980, 644, 5, 001, 466, 5, 101, 195, 5,248, 959; 5,278, 540BRIEF DESCRIPTION OF THE INVENTIONThe present invention seeks to overcome the disadvantages of prior art attempts and provides a relatively inexpensive and reliable earthquake sensor. REF: 25569 There is provided in this manner according to a preferred embodiment of the present invention, an earthquake sensor comprising a base support, a first element pivotably supported on the base support at a first pivot location; a second element pivotably supported on the first element at a second pivot site and the operating sensor apparatus for detecting the vibration actuated by the earthquake of the second element, and for providing an indication of its output therefrom. Preferably, the alarm apparatus that responds to the output indication is provided, to provide an auditory alarm indicating the occurrence of an earthquake. According to a preferred embodiment of the present invention, the sensor apparatus responds to the relative displacement of the first and second elements. Furthermore, according to a preferred embodiment of the present invention, the sensor apparatus is located intermediate in the first and second pivot sites. According to a preferred embodiment of the present invention, the sensor apparatus comprises the piezoelectric apparatus.
Furthermore, according to a preferred embodiment of the present invention, an adjustment device is provided, the adjustment device being operative to change the amplitude of the vibration activated by the earthquake of the second element, required to provide the output indication from the sensor device. Additionally according to a preferred embodiment of the present invention, the sensor apparatus responds to the frequencies induced in the base support in the range substantially at 0.1 Hz and 10 Hz to provide the output indication.
BRIEF DESCRIPTION OF THE DRAWINGSThe present invention will be more fully understood and appreciated from the following detailed description, taken in conjunction with the drawings in which:Figure 1A is a pictorial illustration of the earthquake alarm apparatus constructed and operative in accordance with a preferred embodiment of the present invention;Figure IB is a sectional illustration of the apparatus of Figure 1A, taken along lines B-B in Figure 1A;Figure 2 is a sectional illustration of part of the apparatus of Figures 1A and IB, taken along lines II-II in Figure IB;Figure 3 is a simplified block diagram of the electrical circuitry used in the apparatus of Figures 1A and IB;Figure 4 is a sectional illustration of an alternative embodiment of the apparatus of Figures 1A-2;Figure 5 is a simplified illustration of the earthquake alarm apparatus constructed and operative in accordance with another preferred embodiment of the present invention; YFigures 6, 7, 8, 9, 10 and 11 are each simplified illustrations of a sensor module useful in a preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED MODALITIESReference is now made to Figures 1A and IB, which illustrate the earthquake alarm apparatus constructed and operative in accordance with a preferred embodiment of the present invention. The earthquake alarm apparatus comprises a housing 10, typically formed of plastic and having a transparent or translucent top portion 12 accommodated to receive a lamp 14 or other visual alarm indicator. In the illustrated embodiment, a tang 16 with an upward pointing tip is mounted on a base portion 18 of the housing 10, such that the tip of the pin 16 defines a first pivot site 20. Pivotably mounted on the tip of the pin 16 for pivotable movement about the first pivot site 20, there is a first element 22, which can be produced from one or more pieces and preferably has a first weight 24 associated with it, at a site that lies below the first pivot site 20. The first element 22 preferably similarly defines a second pin 26 with the tip directed upwards, such that the tip of the second pin 26 defines a second pivot site 30. Mounted pivotably on the point of the pin 26 for pivotable movement about the second pivot site, there is a second element 32, which can be made from one or more parts and preferably has a vibration sensor-triggered by the earthquake, associated with it at a site that lies below the second pivot site 30, but above the first site of the earthquake. ivote 20. The sensor 34 of the vibration actuated by the earthquake is operative to detect the vibration triggered by the earthquake of the second element 32 and to provide an indication of the output signal thereof. In the illustrated embodiment, the sensor 34 of the vibration actuated by the earthquake comprises a conductive sensing rod 35 which passes through a conducting sensor ring 36, as shown in Figures IB and 2. The conductive sensing rod 35 is coupled at its upper end to the second element 32. A second weight 33 is coupled to the lower end of the conductive sensing rod 35. The conductive sensing ring 36 is illustrated in Figure 2 as a flexed wire, the ends of which are press fit within the sites 37 and 38 of the first element 22. It is appreciated that many other methods of forming the ring 36 and assembling it with the first element 22 are possible.
The combined mass of the first element 22 and the first weight 24 is typically from about 500 to 600 grams. The vertical distance between the first pivot site 20 towards the center of gravity of the first element 22 and the weight 24. is typically about 40 mm. The mass of the second element 32, the second weight 33 and the conductive sensor rod 35, is typically approximately 50-55 grams. The vertical distance between the second pivot site 30 and the center of gravity of the second element 32, the second element 33 and the conductive sensor rod 35, is typically from about 60-65 mm. The vertical distance between the first pivot site 20 and the second pivot site 30, is typically approximately 80-100 mm. The conductive sensor rod 35 is typically made of copper with a thin gold plate. The diameter of the conductive sensor rod 35 is typically from about 1 to 1.5 mm. The inner diameter of the conductive sensor ring 36 is typically from about 3 to 4 mm. It will be appreciated by one of ordinary skill in the art that the earthquake alarm apparatus 10 will respond to vibrations in the range of 0.1 to 10 Hz. It will also be appreciated that the earthquake alarm apparatus 10 will respond to the vibrations induced by the earthquake. , which are generally in the frequency range of approximately 2 to 8 Hz. It will also be appreciated that the earthquake alarm apparatus 10 will respond less to vibrations not induced by earthquakes, such as sonic explosions or near heavy traffic, which they are generally in the frequency range of 14 to 25 Hz. The alarm apparatus that responds to the indication of the output signal is preferably provided, for the provision of an auditory and / or visual alarm indicating the occurrence of an earthquake . In Figure 3 a simplified block diagram of the electrical circuitry associated with the alarm apparatus is shown. The conductive sensing rod 35 and the conductive sensing ring 36 are electrically connected in series with the lamp 14, the battery 40, the buzzer 41, the switch 42 and the electronic element 43. The switch 42 is used to turn on the alarm apparatus. earthquake After the occurrence of an earthquake, the vibrations cause the rod 35 to come into contact with the ring 36, whereby the electrical circuit is completed and the buzzer 41 and the lamp 14 are operated. The electronic element 43 determines the duration of the the operation of the buzzer 41 and the duration and type of illumination, such as stable or flashing, of the lamp 14. Reference is now made to Figure 4, which may be identical to the embodiment of Figures 1A, IB and 2 but that includes an adjustable sensitivity characteristic which will now be described. A knob 50 operable by the user operates a rack and pinion gear train 52, which raises or lowers an arm 54, thereby modifying the distance between the conductive sensor ring 36 and the second weight 33. When decreasing or Increasing the distance between the conductive sensor ring 36 and the second weight 33, changes the required vibrational amplitude, necessary to produce an alarm. It will be appreciated that the unwanted movement in the rack-and-pinion gear 52 is sufficiently large, so that the earthquake alarm apparatus of Figure 4 will have substantially the same frequency response characteristics as the embodiment described hereinabove. with reference to Figures 1A-2. Reference is now made to Figure 5, which is a simplified illustration of earthquake alarm apparatus constructed and operative in accordance with another preferred embodiment of the present invention. The apparatus comprises a base element 78, which can be fixed to a wall or other suitable object, and defines in a sharp flexion therein, a first pivot site 80. Vertically mounted on the element 78 for pivotal movement about the first pivot site 80, there is a first element 32, which can be made from one or more pieces and preferably has a first weight 84 associated with it at a site that lies below the first pivot site 80. The first element 82 preferably defines similarly a second pivot site 90. Pivotably mounted for pivotal movement about the second pivot site 90, there is a second element 92, which can be made from one or more parts and preferably has a vibration sensor 94 driven by the earthquake , associated with it in a site that lies below the second pivot site 90, but above the first pivot site 80. The vibration sensor 94 operated by the earthquake is operative to detect the vibration triggered by the earthquake of the second element , and to provide an indication of output signal thereof. The second element 92 is preferably provided with a second weight 96 at a site below the sensor 94 of the vibration actuated by the earthquake. It may be appreciated by some of ordinary skill in the art that the earthquake alarm apparatus in Figure 5 will have substantially the same frequency response characteristics as the embodiment already described hereinabove with reference to Figures 1A-2. Preferably , the alarm apparatus is provided which responds to the indication of the output signal, to provide an auditory and / or visual alarm indicating the occurrence of an earthquake, substantially as illustrated and described hereinabove with reference to the Figures 1A-3. Reference is now made to Figures 6, 7, 8, 9, 10 and 11, which are each, simplified illustrations of a sensor module useful in a preferred embodiment of the present invention. It is appreciated that the sensor module shown in each of Figures 6 -11, simply replaces the sensor 34 of the vibration actuated by the earthquake of the embodiment illustrated in Figures 1A-3. Referring now to Figure 6, a weight 105 is fixed to a base 106, which is in mechanical communication with a piezoelectric element 107. The piezoelectric element 107 is operative to produce electrical signals in response to the mechanical stress caused by the displacement of the weight 105 and the base 106, induced by the vibration of the earthquake. Reference is now made to Figure 7, which illustrates a weight 115 suspended from the pivot point 120, and operative to strike any of the piezoelectric elements 121 and 122 after the occurrence of an earthquake. The piezoelectric elements 121 and 122 convert the resulting mechanical voltage to an electrical signal. Reference is now made to Figure 8, which illustrates a generally spherical weight 125, operative to roll on the surface 126. The vibrations of the earthquake cause the weight 126 to roll and strike any of the sensors 127 or 128. The sensors 127 and 128 may be piezoelectric elements or contact microphones, which convert the shock to an electrical signal. Reference is now made to Figure 9, which illustrates a mercury bath 130 with an electrode 132 permanently immersed therein. The electrodes 134 and 136 are located above the mercury bath 130 and initially are not in contact with the bath.
The vibrations of the earthquake cause the mercury to come into contact with any of the electrodes 134 or 136, thereby closing the set of alarm circuits. Reference is now made to the. Figure 10, which illustrates a magnet or magnet 140 suspended from the pivot point 142 and the adjacent stationary winding or coil 144. The movement induced by the vibration of the earthquake of the magnet 140 with respect to the winding or coil 144, produces an electrical signal . Reference is now made to Figure 11, which illustrates an arrangement similar to Figure 10, except that in the embodiment illustrated in Figure 11, the winding 154 is suspended from the pivot point 152 and the magnet 150 is stationary. It will be appreciated by those skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove, but rather includes equivalents and variations thereto. The scope of the present invention is defined solely by the following claims:It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.
Having described the invention as above, property is claimed as contained in the following: