Abstract:
An earthquake actuated micro switch includes a ball which falls into a micro switch actuating position when disturbed. The ball normally resides in a shallow ball seat. A sufficient disturbance causes the ball to escape the ball seat, and fall into a switch seat. When the ball comes to rest in the switch seat, a lower surface of the ball pushes a micro switch actuator, thereby actuating the micro switch.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to earthquake safety devices, and more particularly to devices which actuate a micro switch as a result of an earthquake. 
   There is world wide concern regarding the effects of earthquakes. In recent years, earthquakes occurring around the world resulted in tens of thousands of deaths. Although modem building codes drastically reduce the human harm resulting from earthquakes, there is still a significant likelihood that deaths will occur even in modern countries. Although building codes have been successful in reducing the catastrophic collapse of structures, there is often substantial secondary damage resulting from gas fires, broken electrical wiring, and the like. Various devices have been developed to turn off gas lines and the like, either directly through a mechanical action, or indirectly through actuation of an electrical switch. 
   U.S. Pat. No. 4,185,507 for “Acceleration Responsive Tripping Mechanism,” describes a ball sitting on a pedestal. When motion occurs, the ball falls off the pedestal into a surrounding chamber (or dish), causing the chamber to lower against a spring, and to trip a micro switch. Disadvantageously, the device of the &#39;507 patent includes a number of moving parts including a spring, vertically moving piston, and levers. Devices such as this are generally mounted, and forgotten. There is typically little to no inspection or maintenance, and as a result, such complexity is an invitation to failure. 
   U.S. Pat. No. 4,261,379 for “Vibration/Temperature Sensitive Valve Operating Apparatus,” describes a ball siting in a cup. Motion causes the ball to fall out of the cup, and the cup raises slightly, this motion releases a trigger which results in the desired actuation. Unfortunately the &#39;379 patent also includes substantial mechanical complexity, including several arms, springs, and pins. Such mechanical complexity is undesirable for the reasons cited above. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention addresses the above and other needs by providing an earthquake actuated micro switch including an encased ball which falls into a micro switch actuating position when disturbed. The ball normally resides in a shallow ball seat. A sufficient disturbance causes the ball to escape the ball seat, and fall into a switch seat. When the ball comes to rest in the switch seat, a lower surface of the ball pushes a micro switch actuator, thereby actuating the micro switch. 
   In accordance with one aspect of the invention, there is provided an earthquake sensor comprising a ball, a switch body having a floor, a ball seat on the floor, a switch seat in the floor, and an electrical switch residing under the floor and having an upward facing switch actuator positioned at least partially under the switch seat. The ball resides in the switch body, wherein the ball is positionable by the ball seat when the floor is functionally in the horizontal plane. Motion of the body allows the ball to escape the ball seat and fall into the switch seat, wherein the switch seat is of sufficient diameter and shape to allow the ball, if residing in the switch seat, to actuate the switch actuator. A four conductor cable is electrically connected to the electrical switch. The conductor cable includes a normally open conductor, a normally closed conductor, a neutral conductor, and a ground conductor. A set control is actuable from external to the switch body for moving the ball from the ball seat to the switch seat, and a reset control is actuable from external to the switch body for moving the ball from the switch seat to the ball seat. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: 
       FIG. 1A  is a side view of a motion actuated switch according to the present invention. 
       FIG. 1B  is an end view of the motion actuated switch. 
       FIG. 1C  is a top view of the motion actuated switch. 
       FIG. 2A  is a cross-section view of the interior of the motion actuated switch taken along line  2 — 2  of  FIG. 1C , with a ball in a ball seat. 
       FIG. 2B  is a second cross-section view of the interior of the motion actuated switch taken along line  2 — 2  of  FIG. 1C , with the ball in a switch seat. 
       FIG. 2C  is a detailed view of the ball seat. 
       FIG. 3A  is a cross-section view of a base only of the motion actuated switch taken along line  2 — 2  of  FIG. 1C , showing a set screw used to retain a cable in the base. 
       FIG. 3B  is a second cross-section view of the base only of the motion actuated switch taken along line  2 — 2  of  FIG. 1C , showing an O-Ring and O-Ring retainer used to retain the cable in the base. 
       FIG. 3C  is a third cross-section view of the base only of the motion actuated switch taken along line  2 — 2  of  FIG. 1C , showing a second micro switch having a plunger type actuator. 
       FIG. 4A  shows cross-sectional view of a second set screw used to secure a switch in the base taken along line  4 — 4  of FIG.  1 A. 
       FIG. 4B  shows cross-sectional view of two screws with washers used to secure the switch in the base taken along line  4 — 4  of FIG.  1 A. 
       FIG. 5  shows a bracket used to secure the switch in the base. 
       FIG. 6A  shows a top view of a center body portion having an inner shaped wall. 
       FIG. 6B  shows a top view of the center body portion having a second inner shaped wall suitable for use with a reset control. 
       FIG. 7A  is a cross-sectional view taken along line  2 — 2  of  FIG. 1C  of an embodiment of the motion actuated switch including a set control and reset control. 
       FIG. 7B  is a second cross-sectional view taken along line  2 — 2  of  FIG. 1C  of an embodiment of the motion actuated switch including the set control and reset control. 
       FIG. 8  is a side view of the motion actuated switch showing set and reset controls. 
       FIG. 9A  is a cross-section view of the interior of the motion actuated switch taken along line  2 — 2  of  FIG. 1C , with a ball in the ball seat and with a gas inlet and gas outlet. 
       FIG. 9B  is a second cross-section view of the interior of the motion actuated switch taken along line  2 — 2  of  FIG. 1C , with the ball in the switch seat and with the gas inlet and the gas outlet. 
   

   Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
   DETAILED DESCRIPTION OF THE INVENTION 
   The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims. 
   The present invention addresses the above and other needs by providing a motion actuated switch  10  including a center body portion  12 , a cover  14 , and a base  16  as shown in side view in FIG.  1 A. The motion actuated switch  10  has some similarity to the earthquake actuated automatic gas shutoff valve described in U.S. Pat. No. Re. 38,220 issued to the inventor of the present invention. U.S. Pat. No. Re. 338,220 is herein incorporated by reference. 
   The motion actuated switch  10  includes a sight port  13  which allows viewing of the position of a ball  28  (see FIG.  2 A). Cover gasket  15  is positioned between the cover  14  and center body portion  12 . A base gasket  17  is positioned between the base  16  and the center body portion  12 . A cable  20  having four conductors  22  extends from the base  16 . Pads  18  extend from the bottom of the base  16 , and mounting screws  24  extend through the base  16  and pads  18 . The pads  18  are preferably ½ inch square, and the mounting screws  24  are preferably approximately ¼ inch thread screws. 
   An end view of the motion actuated switch  10  is shown in  FIG. 1B , and a top view of the motion actuated switch  10  is shown in FIG.  1 C. Four cover screws  26  on for corners of the cover  14  attach the cover  14  to the center body portion  12 . It is further seen that three mounting screws  24  extend through the base  16 , which cover screws  26  and mounting screws  24  are preferably allen head screws. The center body portion  12 , cover  14 , and base  16  are preferably made from aluminum, and the screws  24 ,  26  are preferably made from stainless steel. 
   Cross sectional views of the interior of the motion actuated switch  10  taken along line  2 — 2  of  FIG. 1C  are shown in  FIG. 2A  with the ball  28  residing in a ball seat  29  (see  FIG. 2B ) and in  FIG. 2B  with the ball  28  residing in a switch seat  31  (see FIG.  2 A), wherein the ball seat  29  and the switch seat  31  are formed in a floor  33  defined by the top surface of the base  16 . The floor  33  is functionally horizontal, i.e., the ball seat  29  retains the ball  28  and the switch seat  31  retains the ball  28 , once the ball  28  is in either seat  29 ,  31  in the absence of interference (e.g., motion) of the motion actuated switch  10 , when the base  16  is on a horizontal surface. The sight port  13  (see  FIG. 1A ) may be located to see the ball  28  in either the ball seat  29  or in the switch seat  31 . The ball  28  is preferably made from chrome steel. 
   A preferred ball seat  29  is shown in FIG.  2 C and is described in detail in U.S. Pat. No. Re. 338,220, incorporated by reference above. The ball seat  29  comprises a conical depression having a diameter D. The diameter D of the ball seat  29  determines the actuation G level at higher frequencies. When used to turn off gas service, the standard calls for the closing of the valve at a G level of over 0.4 G at 10 Hz compared to 0.15 G at 2.5 Hz. For the same G level the movement at 10 Hz is only {fraction (1/16)} that at 2.5 Hz. The diameter D of the seat can be made large enough to contain the 10 Hz movement while allowing the lower frequencies to actuate. To meet the standard, the diameter D is preferably about 0.375″. The angle of the cone is preferably about 13 degree. Of course, the ball seat can be machined out and an insert added with a different angle and diameter for different actuation requirements. At 7.5 Hz and 10 Hz, the ball is shaking back and forth and cannot escape the ball seat just below the actuation level. A hole  29   a  at the apex of the ball seat  29  may be provided to improve ball seating stability for light balls  28 . 
   The switch seat  31  is preferably large enough to allow the ball  28  to actuate the switch  30  when the ball  28  rests in the ball seat  31 , and the ball seat  31  is preferably small enough to allow the ball  28  to be reset by use of the reset control (see FIG.  7 B). It is thus seen that the size of the ball seat  31  is a function of the size of the ball  28 , and of the position of the switch actuator  32 . 
   A switch  30  is shown residing in the base  16 , and a switch actuator  32  extends from the switch  30 . The switch  30  is positioned to position the switch actuator  32  below the switch seat  31 , so that when the ball  28  is resting in the switch seat  31  (as shown in FIG.  2 B), the ball  28  pushed the switch actuator  32  down, and thereby actuates the switch  30 . The switch  30  is preferably a micro switch, and more preferably a Single-Pole Double-Throw (SPOT) micro switch, for example, a part number 311 SX2-T micro switch manufactured by Honeywell in Morristown, N.J. While a switch with a straight switch actuator  32  is described herein, a switch having any suitable switch actuator is intended to come within the scope of the present invention, for example, a roller lever. 
   The switch  30  preferably has three contacts  34 . The cable  20  preferably includes four conductors  22  comprising a normally open conductor, a normally closed conductor, a neutral conductor, and a ground conductor. Three of the four conductors  22  are electrically connected to the switch  30 , and one of the conductors  22  is electrically connected to the base  16 , preferably by a ground screw  36 . The cable  20  preferably has a jacket wall and is approximately 0.228 inches in diameter, and the conductors  22  are preferably 20 AWG insulated conductors. A preferred cable is a part number NQ-420 SJ available from National Wire and Cable Corporation in Los Angeles, Calif. 
   A cross-section view of a base  16  only of the motion actuated switch  10  taken along line  2 — 2  of  FIG. 1C  is shown in  FIG. 3A. A  set screw  38  is used to retain the cable  20  in the base  16 . The cable  20 , the entry hole in the base  16  for the cable  20 , the set screw  38 , and the threaded hole in the base  16  for the set screw  38 , are preferably coated with a sealant, and more preferably with Dow Coming RTV 734 Adhesive Sealant. The set screw  38  is preferably a ¼-20 by ⅜ inch hex socket set screw, preferably having a cup point. 
   A cross-section view of a second embodiment comprising a base  16   a  only of the motion actuated switch  10  taken along line  2 — 2  of  FIG. 1C  is shown in  FIG. 3B  showing an O-Ring  40  and O-Ring  42  retainer used to retain the cable  20  in the base  16 . 
   A cross-section view of an embodiment comprising a base  16   b  only of the motion actuated switch  10  taken along line  2 — 2  of  FIG. 1C  is shown in FIG.  3 C. The base  16   b  includes a second micro switch  30   a  having a plunger type actuator  32   a . The micro switch  30   a  is positioned with the actuator  32   a  approximately centered under the switch seat  31  and at a height which allows the ball  28  to actuate the micro switch  30   a  when the ball  28  resides in the switch seat  31 . 
   The switch  30  is shown in  FIG. 4A  fixed in the base  16  by a second set screw  46 , in a cross-sectional view taken along line  4 — 4  of FIG.  1 A. The switch  30  is held between the set screw  46  and a switch support surface  44 . The set screw  46  is preferably sealed using RTV 734 Adhesive Sealant. A second embodiment is shown in  FIG. 4B  wherein two screws with washers  53  hold the switch  30  against the switch support surface  44 . A short set screw  46   a  resides in an opening  47  in the base  16 , which opening  47  is used to drill and tap screw holes, and to install the screws with washers  53 . 
   In another embodiment, the switch  30  is attached to the base  16  by a switch bracket  48  shown in FIG.  5 . The bracket  48  is attached to the switch  30  by a switch screw  50  and switch nut  54 , with a switch washer  52  between the switch  30  and the nut  54 . A bracket screw  56  may be used to attach the bracket  48  to the base  16 , with a bracket washer  58  between the head of the bracket screw  56  and the bracket  48 . While the methods shown in  FIGS. 4A ,  4 B, and  5  are preferred, a motion actuated switch with a switch attached by any method is intended to come within the scope of the present invention. The washers  52  and  58  are preferably lock washers. 
   Top views of two embodiments of the center body portion are shown in  FIGS. 6A and 6B . The center body portion  12  has an oval shaped first inner shaped wall  60   a . The inner shaped wall  60   a  provides a surface for deflecting the ball  28  toward the switch seat  31 , and preferably the inner shaped wall  60   a  is shaped to be within one ball radius from the switch seat  31 . A second center body portion  12   a  has a second inner shaped wall  60   b  having additional reliefs  61  provided for second arms  70  (see  FIG. 7A ,  7 B). The cover  14  is attached to the center body portions  12 ,  12   a  using screw holes  62  in the center body portions  12 ,  12   a.    
   An embodiment of a motion actuated switch with set and reset controls is shown in  FIGS. 7A and 7B . The set control comprises a set shaft  64  and at least one first arm  66 . The reset control comprises a reset shaft  68  and at least one second arm  70 . There are preferably two arms  66  and two arms  70 , and the arms  70  may include hands  72  at lower ends, which hands  72  contact the ball  28  below center to facilitate lifting the ball  28  out of the switch seat  31  (see FIG.  2 A). The ball  28  is shown in the ball seat  29  (see  FIG. 2B ) in  FIG. 7A , wherein rotating the arms  66  toward the ball  28  caused the ball  28  to escape the ball seat  29 . The ball  28  is shown in the switch seat  31  in  FIG. 7B , wherein rotating the arms  70  toward the ball  28  lifts the ball  28  out of the switch seat  31 . Additional details and embodiments of set and reset controls are described in detail in U.S. Pat. No. Re. 338,220, incorporated by reference above. 
   The shafts  64 ,  68  preferably extend through the side of the center body portion  12  as shown in FIG.  8 . The set control and reset control are thus actuable from external to the center body portion  12  to set or to reset the ball. 
   In some situations both a mechanical gas shutoff and an electrical switch may be desired or required. A motion actuated switch combining both a mechanical gas shutoff and an electrical switch is shown in  FIGS. 9A and 9B . A preferred second ball  28   a  and second ball seat  31   a  are described in U.S. Pat. No. Re. 338,220, incorporated by reference above. The ball  28   a  is shown on the ball seat  29  in  FIG. 9A , wherein a gas flow entering at an inlet  80  flows through the body  12  and out an outlet  82 , and the switch  30  is not actuated. The ball  28   a  is shown on the switch seat  31   a  in  FIG. 9B , wherein the gas flow entering at the inlet  80  is blocked from flowing through the body  12 , and the switch  30  is actuated. The cable  20  may, for example, be connected to a bell or other alarm, or to a remote site using a wired (e.g., phone lines or internet type connection) or wireless transmission. The cable  20  may further be connected to an electrical valve to turn off a flow of gas or water or other liquid, or may turn off an electrical circuit. 
   While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.