Patent Publication Number: US-7898427-B1

Title: Automatic oven shutoff fire prevention

Description:
FIELD OF THE INVENTION 
     This invention relates to domestic fire prevention and particularly to fires originating from gas or electric stoves. 
     BACKGROUND AND INFORMATION DISCLOSURE 
     A principle cause of domestic fires is well known to originate from electric appliances and particularly from stoves, electric or gas fueled. 
     A particular factor that increases the cost of fire originating from stoves is that it is common practice to put a meal in the oven or to warm up on the stove and then to retire to another part of the house or “step outside” the house while the food is cooking. This is particularly true when the food being cooked is a roast or turkey or other item that often requires several hours for the cooking process. 
     Sometimes, the cook forgets that he has “something on the stove” and goes to a movie or other event and finds a house full of smoke/fire when he/she returns. 
     The technology of fire protection has grown over the years commensurate with advances in electronics. 
     For example, U.S. Pat. No. 5,297,636 discloses a fire extinguishing system for a residential cook-stove including a fire extinguisher mounted above a hood in a cabinet positioned in a cabinet over a cook stove. The fire extinguisher is connected by a flexible hose to nozzles within the hood to spray fire retardant over the cook-stove. 
     U.S. Pat. No. 7,176,805 B2 discloses an intelligent thermostat which, upon detection of a flammable gas regulates operation of appliances that have sources of ignition. This condition is detected by a flammable gas detector which then communicates with the appliances. The device may then send a visual signal to the occupant or sound and alarm. 
     U.S. Pat. No. 7,113,090 discloses a personal security network where an individual&#39;s system of security devices is connected to a central security system. 
     U.S. Pat. No. 6,965,313 discloses a personal security network where an individual&#39;s system of devices is connected to a central network. The user is enabled to set up personal alarms and alert services, to alert designated individuals. 
     U.S. Pat. No. 6,826,267 discloses an array of appliances controlled by a source of command fields defining operations to be performed within a contact sub-field. 
     U.S. Pat. No. 6,791,467 discloses a system for remotely controlling devices and includes an adaptive remote controller The remote controller is rf based and has the ability of two way communication with the devices. 
     U.S. Pat. No. 661,340 discloses a personal security network where an individual&#39;s system of security devices are connected to a central security network. The user may setup personalized alarms. And alert the individual when an alert situation occurs. 
     None of these devices address two immediate needs that a property owner requires when he is faced with the situation of imminent danger from fire particularly when he is “out of the house” and, for one reason or another has left his stove on and smoke is emanating from the stove. 
     One need is to disconnect power from the stove immediately upon receipt of the alarm signal. 
     Another need is to alert the owner to take immediate action such as calling a fire department particularly if he is not at home. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide a system for immediately turning off power to a stove (or oven) that is emitting smoke and/or heat. 
     It is another object to immediately alert the owner that the system has detected smoke, regardless of where the owner is located. 
     It is another object that the system be operable in any one of several modes, selected by the operator. These modes include: 
     a first mode where the object is simply to shut the power off and telephone a responsible party; 
     a second mode where the object is to transmit “ON” signal regardless of the status Smoke/heat detector such as when an operator simply requires that a responsible party be notified of an urgent need for help such as an ongoing burglary: 
     a third mode where the operator simply wishes to disempower the alarm for whatever reason; 
     a fourth mode where the operator wishes to delay turning the system on such as when smoke that has been generated has not been completely cleared. 
     It is another object that the system be selectively operable in an area of a plurality of such systems and it is required that response generated by a single system not be “crossed” with other systems. 
     This invention is directed toward a system which interrupts power (gas or electric) to a stove when the system detects smoke or heat in the vicinity of the stove. The system simultaneously sends a signal out to a selected phone. 
     The system includes a cordless detector that is placed within 25 meters from the stove 
     The system also generates a continuous alarm until the user initiates a reset action. 
     The system also provides that the stove continue to operate, according to the discretion of the operator, if the smoke has not been completely cleared from the vicinity of the oven. 
     The present invention includes three RF sections. 
     One RF section is a SMOKE DETECTOR section that detects smoke and broadcasts detection of smoke and an address of the smoke detector 
     Another RF section is an :RF OUTLET ADAPTER. that receives the combination signal and shuts off the power supply (electrical or gas) and provides to a Phone dialer the address of a designated party. 
     Another RF section is an RF Phone dialer that receives the transmitted signal including the phone number and calls the responsible party. 
     While the RF OUTLET ADAPTER receives an ON signal, power is provided uninterrupted to the stove for normal operation of the stove. 
     When the RF OUTLET ADAPTER receives an OFF signal, the RF adapter turns off power to the stove. Power remains OFF until a “reset” signal is received. The “reset signal” is generated by the operator. 
     In one version of the invention, the system is directed to the situation where there is only one isolated premise that must be provided with the smoke detection system. 
     In another version of the invention, such as a condominium or a complex of row houses, the system provides for several closely spaced premises where each premise requires independent protection. 
     In this latter situation, a memory of addresses and corresponding telephone numbers are made accessible to the function controllers arranged so that no cross interaction occurs that would confuse the operation of the system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of the RF Smoke detector section. 
         FIG. 2A  is a schematic diagram of the RF Outlet Adapter for an electrically powered oven. 
         FIG. 2B  is a schematic diagram of the RF Outlet Adapter for an electrically powered oven. 
         FIG. 3  is a schematic diagram of the RF Phone Dialer section. 
     
    
    
     DISCUSSION OF THE DRAWINGS 
     Turning now to a discussion of the drawings,  FIGS. 1-3  are schematic diagrams of the “AUTOMATIC OVEN SHUT OFF” system  10  of this invention. 
     The system  10  comprises: 
     the smoke detector section ( FIG. 1 ) 
     the RF Adapter section, ( FIG. 2A  shows the adaptation to an electric oven and  FIG. 2B  shows the adaptation to a gas oven); 
     the phone dialer section ( FIG. 3 ). 
     The smoke detector section ( FIG. 1 ) includes a smoke detector  26  that sends a “smoke” signal to a 4-1 multiplexor.  21 . 
     Multiplexor  21  responds to the Smoke signal according to a mode selected manually by closing combinations of switches  21 A, and  21 B. Inputs  21 A and  21 B are typically pushbutton switches that enable Multiplexor  21  to apply the selected mode ( 1   a ,  1   b ,  1   c ,  1   d ,) to functional controller  4 . 
     Table I is the truth table for applying the combinations of input  21 A,  21 B to selecting as outputs, any one of the inputs ( 1 A,  1 B,  1 C,  1 D) to the multiplexor  21 . 
     The operator (e.g., homeowner) selects an operating mode (inputs  1   a ,  1   b ,  1   c ,  1   d ) manually by pressing any one of the four enable combinations available at manual control  21 A. 
     Input  1 A of MUX  21  is connected directly to the smoke detector,  26 , Manual selection of input  1 A sets the system in the “auto detection mode”. This is the normal operation mode. When the smoke/heat detector detects smoke or heat, the functional controller  4  turns. the RF transmitter  5  to ‘smoke on’ condition causing the RF Transmitter  5  to broadcast a “smoke on” signal. When the smoke detector  26  no longer detects smoke/heat. RF Transmitter will automatically turn off and transmit a “smoke off” signal. 
     Manual selection of input  1 B to multiplexor,  21  will force the functional controller  4  to generate the RF transmitter “ON” signal regardless of the status Smoke/heat detector  26   
     Manual selection of signal input  1 C applied to multiplexor  21  will turn the power off and shut the system down. 
     Manual selection of signal input  1 D applied to multiplexor  21  applies signal input  26   a  from the Smoke Detector  26  “Ored” with signal input  2 B to reset the system with a programmable time delay. 
     This mode is activated by the operator when he wishes the system to activate after a selected delay period. 
     In addition to the “mode signal” from the MUX  21  input into functional controller  4 , an address (physical location)  4 E of the smoke detector  26  is also input into the functional controller  21 . 
     The address is written one time in an address register and is retained as a permanent reference for the operation of the system. 
     This arrangement ensures that the addresses of events of turning off power to the stove and calling a responsible telephone party correspond only to the address of the smoke detector originating the transmitted Smoke-address signal. Each system has a unique address and responds only to the matching address. 
     The functional controller  4  generates a “combined” signal being the “MUX” signal (representing mode from MUX  21 ) and the “address signal” from the Address register  5   
     The functional controller  4  passes the combined signal to the input terminal of RF Transmitter  5 . The RF transmitter  5  broadcasts the combined signal to the RF Adapter section shown in  FIG. 2A  if the stove is electrically powered, or  FIG. 2B  if the stove is gas powered. 
     If there are numerous premises in the area requiring separate fire protection, then there are numerous entries in the address library  11  of the RF Adapter section. —one entry for each premise occupied by its own smoke detector  26 . 
       FIG. 2A  is a schematic diagram of the RF Outlet Adapter for an electrically powered oven. The Receiver  7  receives the combined signal from the RF transmitter  5 . The output from Receiver  7  enables multiplexor  8 . If the power  10  to the oven is ON, then a “high” signal  8   a  is input to multiplexor  8 . causing multiplexor  8  to signal function controller  9  to turn the power switch  10  off. 
     The functional controller  9  will compare the address included in the combined signal to the address of an OFF/ON POWER switch  10  supplying electric power to oven conductor  19  to confirm that the incoming combined signal applies to the OFF/ON POWER switch  10 . 
     If the power  10  to the oven is already OFF, then a “low” signal  8   b  is input to multiplexor  8  and multiplexor  8  will not respond to any input from the RF Receiver  7 . 
     If the power  10  to the oven is ON, then a “hi” signal  8   b  is input to multiplexor  8  and multiplexor  8  will respond to any input from the RF Receiver  7 . by turning the control of the solenoid switch OFF 
       FIG. 2B  is a schematic diagram of the RF Outlet Adapter for a gas powered stove. This version ( FIG. 2B ) is identical to the electric powered version ( FIG. 2A ) except that the functional controller  9  sets the on/off solenoid switch  16  to control (on-off) the gas supply to the gas oven, depending on the status high-on  13 A or low off  13 B. 
       FIG. 3  is a schematic diagram of the RF Phone dialer. The RF receiver  17  receivers the combined signal (Smoke-On-Address). 
     The functional controller  21  of the RF Phone adapter section applies the address portion of the signal using comparator  20  to lookup the phone number in the lookup table  19 . 
     The functional controller  21  then applies the phone number to enable the phone dialer  18  to call a cell phone or emergency operator listed with the corresponding phone number in library  19 . 
     A system has been described whose basic function is to detect a smoke/heat signal generated by an electrical/gas powered device, shut off power to the device, and phone a responsible party regarding the detection of the smoke/heat. The base parts of the system include a smoke detection section, a power shut off section, and a phone dialer section each working in combination with the other sections to accomplish the objectives of the system 
     Modifications and variations of the invention may be contemplated after reading the specification and studying the drawings which are within the scope of the invention. I therefore wish to define the scope of my invention by the appended claims.