Abstract:
An alarm device for signaling when an object reaches a specified temperature. The alarm device includes a thermometer for detecting the temperature of the object. The device further includes a switch element which is closed when the thermometer indicates the specified temperature. The closed switch element triggers an alarm, such as a light or a buzzer, which will signal a person monitoring the temperature that the specified temperature has been reached.

Description:
FIELD OF THE INVENTION 
     The present invention relates to temperature sensing devices. In particular, the present invention relates to a thermometer that activates a warning signal when a specified temperature is reached. More particularly, the present invention relates to a thermometer with a needle, where the needle activates a warning signal, such as a light or horn, when a specified temperature is reached. 
     BACKGROUND OF THE INVENTION 
     Temperature sensing devices are well known and widely used in many industrial and consumer applications. Temperature sensing is important for many industries, including food production, where the food can spoil if the proper temperature is not maintained. Cooks can also use a temperature sensing device to monitor the temperature of a grill, other cooking device, or food being cooked. Temperature sensing is also important in industries that use motors and other types of mechanical machinery because high temperatures which may be generated by these devices can shorten the life of the devices or cause a fire if the high temperature goes undetected. Temperature sensing devices are also utilized in scientific experiments that require the monitoring of the temperature. 
     The prior art discloses many temperature sensing devices where a user can simply look at the device to check the temperature. For example, a simple thermometer can be used. However, these devices are inefficient to use because they require constant monitoring. If a user becomes preoccupied with another task, the temperature can rise undetected and cause damage before the elevated temperature is noticed by the user. The prior art also discloses more complex temperature sensing devices where some sort of warning signal is emitted. In one example, a plurality of temperature sensors is placed in various locations in an industrial plant. The temperature sensors are hard wired to a centralized monitoring system where the temperature is monitored. However, the hard wiring of the temperature sensors makes the system susceptible to damage from routine maintenance in the plant because a wire could be damaged during the maintenance. 
     A temperature sensing device that is durable, contains no external components that can be damaged, is inexpensive to manufacture, is portable, and emits a warning signal that is readily detectable would thus be an improvement in the art. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an alarm device configured to detect when an object reaches a specified target temperature. In one embodiment of the invention, a movable element in the form of a needle from a dial-type thermometer physically contacts two contact points of a switch element, thus completing an electric circuit. The closed circuit allows electricity from a power source such as a battery to activate a warning signal device. The activated warning signal device, such as a light or buzzer, thus can alert a person monitoring the temperature that the target temperature has been reached. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top view of the illustrated embodiment of the present invention; 
     FIG. 2A is a top view of the dial thermometer used in the device shown in FIG. 1; 
     FIG. 2B is a top view of the circuit board used in the device shown in FIG. 1; 
     FIG. 2C is a partial side view of the circuit board shown in FIG. 2B; 
     FIG. 3 is a functional block diagram which shows the pathway the electricity travels between the electrical components incorporated into the device of FIG. 1; 
     FIG. 4 is a side view of the illustrated embodiment of the device shown in FIG. 1; and 
     FIG. 5 is a side view of an alternative embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention provides an inexpensive and efficient temperature monitoring device that may be used to monitor the temperature of a variety of objects. Using a dial-type thermometer with a needle, the present invention can warn users when an object reaches a specified target temperature. 
     As used herein, the term “dial-type thermometer” refers to a thermometer wherein the temperature is displayed on a circularly shaped face. The face displays a plurality of temperatures that corresponds to a range of temperatures to be sensed by the thermometer. Typically, the temperature on the face is indicated by the position of a needle relative to the displayed temperatures. 
     As used herein, the term “on” refers to the concept that the circuit contained in the present invention is closed. The closed circuit allows electricity to travel across the circuit. 
     As used herein, the term “off” refers to the concept that the circuit contained in the present invention is open. The open circuit prevents electricity from traveling across the circuit. 
     As used herein, the term “warning device” refers to a device that emits some sort of signal. The signal may be in the form of audio waves or sound, light energy, visually perceptive movement, or any type of signal that may be detected by human senses. 
     As used herein, the term “conventional circuitry” refers to an electrical circuit well known by those skilled in the art. The term is meant to encompass the components of electrical circuits that carry electricity. 
     Referring to FIG. 1, there is shown a top view of the illustrated embodiment of the alarm device generally at  10 . The alarm device  10  comprises a cap  12  made of a translucent material, such as clear plastic, so that when the warning signal, such as a light, is on, the user will be able to detect the light through the cap  12 . It will be appreciated by those skilled in the art that the cap may also be made of a transparent material. The alarm device  10  also comprises a housing  14 . The housing  14  can be made of any suitable material that will conceal and protect the components of the alarm device  10  such as metal, plastic or other material. 
     Referring now to FIG. 2A, there is shown a thermometer  16  used in the alarm device  10 . In the illustrated embodiment, the thermometer  16  is a dial-type thermometer  16 . The thermometer  16  comprises a needle  18 . In the illustrated embodiment, the needle  18  is electrically conductive. It will be appreciated by those skilled in the art that the needle  18  can be made electrically conductive by manufacturing the needle  18  with an electrically conductive material, such as a conductive metal or alloy, or by coating the needle  18  with an electrically conductive material. The needle  18  may be insulated from the rest of the thermometer  16 , in a manner known by those of ordinary skill in the art, to prevent the electricity from flowing through the thermometer  16 . In one example, the needle  18  may be made of a nonconductive material, such as plastic, and coated with a conductive material such that the portion of the needle  18  coated with the conductive material transmits electricity. The thermometer  16  further comprises a face  20 . In the illustrated embodiment, the face  20  of the thermometer  16  is marked with indicia of a temperature gradient that corresponds to the intended temperature range of the thermometer  16 . It will be appreciated that dial-type thermometers are well known by those of ordinary skill in the art. 
     Referring now to FIG. 2B, there is shown a circuit board  30  of the alarm device  10  shown in FIG.  1 . The circuit board  30  comprises a power source  32 . The power source  32  in the illustrated embodiment is a low-voltage battery, such as the lithium-style, long life battery commonly used in many electrical devices, such as watches and flashlights. It will be appreciated by those of ordinary skill in the art that other power sources  32  can be used such as alkaline batteries, solar cells or other low-voltage power sources. The circuit board  30  also comprises a switch element  34 . The switch element  34  comprises two conductive contact points  36 , wherein the contact points  36  are separated from each other by the dielectric material of the circuit board  30 , such that electricity does not flow from one contact point  36  to the other contact point  36 . 
     Referring now to FIG.2C, there is shown a partial side view of the circuit board  30  of FIG. 2B showing the switch element  34 . The contact points  36  extend below the surface of the circuit board  30 . The extension of the contact points  36  below the circuit board  30  allows the electrically conductive needle  18  of the thermometer  16  to simultaneously physically touch the two contact points  36 . In operation, the alarm device  10  of the present invention is typically “off” because the two contact points  36  of the switch element  34  are not contacted by the needle  18 . When the electrically conductive needle  18  simultaneously touches both contact points  36 , electricity travels from one contact point  36 , through the electrically conductive needle  18 , and to the other contact point  36 . Thus, the switch comprising the switch element  34  and needle  18  is closed and the alarm device  10  is “on.” When the alarm device  10  is “on,” electric current flows through conventional circuit traces  42  in the alarm device  10  and causes a warning device  40  to emit a signal. 
     Referring back to FIG. 2B, the circuit board  30  also comprises a diode  38 . The diode  38  may be a conventional diode or a light-emitting diode. It will be appreciated by those of ordinary skill in the art that when the power source  32  comprises a battery, the diode  38  may be omitted from the circuit board  30  because the battery provides DC current. The circuit board  30  also comprises an electronic warning device  40 . In the illustrated embodiment, the warning device  40  is a lightbulb, but it will be appreciated by those skilled in the art that the electronic warning device  40  can be any type of device that emits a warning signal. Other types of warning devices  40  may include, but are not limited to, a horn or a buzzer, or any combination of warning devices. The power source  32 , switch element  34 , diode  38 , and warning device  40  are interconnected by conventional circuit traces  42  well known by those of ordinary skill in the art. The conventional circuit traces  42  transmit current between the battery  32 , the switch element  34 , the diode  38 , and the warning device  40 . 
     In another embodiment, a manual switch in the form of a toggle switch  39  may be added to the conventional circuit traces  42 . In this embodiment, the toggle switch  39  will have a lever (not shown) extending out of the exterior of the housing  14  such that when the specified temperature has been met and the alarm device  10  is “on”, the lever (not shown) on the toggle switch  39  can be moved such that the conventional circuit traces  42  in the toggle switch  39  are open, thus turning the alarm device  10  “off.” The addition of a toggle switch  39  thus allows a user to turn the alarm device  10  “off” when the functionality of the alarm device  10  is not needed. 
     Still referring to FIG. 2B, the circuit board  30  may be mounted for rotation inside of the housing  14  (not shown). Such rotational capability allows the entire circuit board  30  to be moved in either a clockwise or counterclockwise direction indicated by the arrows  41 . The rotation of the circuit board  30  thus allows the position of the switch element  34  to be moved. The movement of the switch element  34  allows the predetermined temperature to be changed by the user. For example, rotation of the circuit board  30  in a counterclockwise direction allows the predetermined temperature to be lowered. Referring back to FIG. 2A, the circuit board  30  may be rotated such that the needle  18  contacts the switch element  34  (shown in FIG. 2B) at 140 degrees instead of 180 degrees. The rotational mounting of the circuit board  30  allows a user to rotate the circuit board  30  such that any specified target temperature within the range displayed on the face  20  may be set. 
     Referring now to FIG. 3, there is shown a functional block diagram which shows the flow of electricity between the electrical components incorporated into the alarm device  10  of the present invention. The power source  32  comprises a battery in this embodiment, but may also comprise a solar cell or an external power source. The power source  32  is connected to the switch element  34 , such that when the switch element  34  is closed, electricity will flow from the power source  32  to the switch element  34  and from the switch element  34  to the diode  38 . It is well known by those of ordinary skill in the art that the diode  38  restricts the flow of electricity to one direction as indicated by the arrows  35 . The electricity will then flow from the diode  38  to the warning device  40 , which in the illustrated embodiment is a light. The electricity will then flow from the warning device  40  back to the power source  32 . 
     Referring now to FIG. 4, there is shown a side view of the alarm device  10  shown in FIG.  1 . The thermometer  16  and the circuit board  30  are shown located inside of the housing  14 . In the illustrated embodiment, the cap  12  is raised such that when light  44  is given off by the warning device  40 , the light  44  is refracted and thus may be detected by a user from the side of the alarm device  10 , as well as from the top of the alarm device  10 . The alarm device  10  is shown with the needle  18  touching the two contact points  36 , such that the switch comprising the switch element  34  and needle  18  is closed and the alarm device  10  is “on.” When the switch element  34  is closed, the warning device  40  emits a warning signal such as light, shown by lines  44 . The side view also shows a temperature sensing device  50  such as a bimetallic spring. It will be appreciated by those of ordinary skill in the art that the temperature sensing device  50  is integral with the dial-type thermometer  16 , such that the needle  18  on the thermometer  16  will be moved as the temperature detected by the temperature sensing device  50  changes. In the illustrated embodiment, the temperature sensing device  50  may include a heat sink to contact the surface of an object such that the temperature of the surface of the object is measured. The illustrated embodiment further comprises a pair of magnets  52 , wherein the magnets  52  are attached to the housing  14  of the alarm device  10 . The magnets  52  may be used to magnetically attach the alarm device  10  to any ferrous surface, such that the temperature of the ferrous surface will be monitored. 
     It will be recognized by those of ordinary skill in the art that high temperatures may damage certain components of the alarm device  10 . For example, high temperatures may cause damage to the power source  32  or the plastic used to construct the housing  14 . These potential problems can be solved with alternative embodiments of the alarm device  10 . In one embodiment, the alarm device  10  may be designed such that only the temperature sensing device  50 , such as a heat sink, contacts the surface of the monitored object. In this embodiment, air circulation will help keep the rest of the alarm device  10  at ambient temperature. In another embodiment, the power source  32  may be thermally insulated from the monitored object such that the power source  32  is not subjected to high heat. These embodiments are only illustrative of ways to protect the components of the alarm device  10  from high heat. It will be appreciated by those of ordinary skill in the art that this invention is meant to cover other embodiments designed to protect the components of the warning device  10  from high heat. 
     It will be appreciated by those of ordinary skill in the art that the illustrated embodiment of the present invention may be used in many applications. For example, the alarm device  10  may be used in an industrial setting. Because the alarm device  10  is inexpensive, a plurality of alarm devices  10  may be attached to many pieces of equipment without imposing a large cost on the user. The alarm device  10  may be used to alert workers at an industrial plant when the temperature of the surface of a motor, pump, gearbox or any other piece of machinery exceeds a specified temperature. Because the alarm device  10  contains an independent power source  32 , the alarm device  10  is portable and no external wiring is needed to connect the plurality of alarm devices  10 . 
     The alarm device  10  of the present invention described with respect to the illustrated embodiment also has many consumer uses. For example, the alarm device  10  may be used by outdoor grilling enthusiasts. The alarm device  10  may be placed on a grill hood or cover and used to alert the cook that a target temperature has been reached and that it is time to start cooking. It will be appreciated by those of ordinary skill in the art that this is just one example of a consumer use and that many other uses exist. 
     The temperature sensing device  50  could also be configured in many other ways known by those skilled in the art for a variety of uses. Referring to FIG. 5, there is shown a side view of an alternative embodiment of the present invention. In this embodiment, the temperature sensing means  50  is configured with a heat sink usable as a probe. It will be appreciated by those of ordinary skill in the art that the probe in this embodiment has a wide variety of uses. For example, the probe could be used to sense the temperature of liquids, foods such as brats, hamburgers, hot dogs, fish, chicken or any other material in which the probe may be inserted. This embodiment may be useful to grilling enthusiasts to ensure that the interior of the meat being cooked has reached a temperature sufficient to ensure that the meat is thoroughly cooked. It will be appreciated by those of ordinary skill in the art that the temperature sensing device  50 , such as the probe, may be connected to the alarm device  10  in a manner such that the alarm device  10  is located remote from the temperature sensing device  50 . This embodiment allows the temperature sensing device  50  to be inserted into the object to be measured such that the alarm device  10  is not subjected to the high heat of the object being measured. 
     The embodiments described herein do not limit the scope of the present invention. In each of its various embodiments, the apparatus and methods of the present invention provides an inexpensive and efficient alarm device for monitoring the temperature of an object, and the present invention may be carried out using embodiments different from those specifically described herein. Therefore, the scope of the present invention is not limited by the description provided by the present specification, but is defined by the appended claims.