Abstract:
The invention relates to an apparatus used for automatically shutting off cooking appliances, such as ovens, stoves, hot pots, toasters, grills, and others. More specifically, the apparatus is secured to a cooking appliance, e.g. to its control panel, and may prevent a cooking appliance from being turned on before a timer is set. The apparatus can also increase the ease with which a cooking appliance knob or other actuator may be used. To automatically shutoff the cooking appliance, the apparatus uses a timing mechanism with a spring. Pressure is exerted on a spring when the timer is set, storing enough force in the spring to enable it to turn the cooking appliance to the OFF position when time has expired. A mechanical stop is in place to keep the spring energy from releasing until the timer reaches the OFF position.

Description:
PRIOR PATENT APPLICATION 
       [0001]    This application is a non-provisional patent application claiming priority to U.S. provisional patent application Ser. No. 60/879,308 filed on Jan. 5, 2007, the disclosure of which is incorporated herein in its entirety by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention is directed to an apparatus used for automatically shutting off cooking appliances, such as ovens, stoves, hot pots, toasters, grills, and others. 
       BACKGROUND 
       [0003]    Conventional cooking appliance knobs are typically connected directly to the cooking appliance, such as an oven or stove, and may be rotated at any time to turn on the cooking appliance. A typical cooking appliance will stay at the chosen heat setting until a cooking appliance knob is manually turned to the OFF position. Controlling the operation of a cooking appliance in this manner presents the danger that a person who turned the appliance on will forget to turn it off, presenting the risk of a fire hazard or other danger. 
         [0004]    Older adults are more likely to forget to turn off a cooking appliance due to the increased possibility of their diminished mental faculties. Among those persons aged  65  and older, 15 percent of men and 11 percent of women suffer from some form of moderate to severe memory impairment, according to the 2002 Federal Interagency Forum on Aging-Related Statistics. Also, according to the Alzheimer&#39;s Association, one in ten people who are 65 years and older are afflicted with Alzheimer&#39;s Disease. Decreased sensory abilities, such as smell, touch, vision and hearing, in older adults places them at a higher risk of forgetting about cooking appliances and, thus, at a higher risk of death or injury from cooking appliance fires. 
         [0005]    Therefore, addressing the special needs of the elderly with regard to cooking appliances and the dangers present in accidentally leaving a cooking appliance on is desirable. 
       SUMMARY 
       [0006]    The invention provides an apparatus that prevents a cooking appliance from being turned on before a timer is rotated from the OFF position. In addition the invention provides an apparatus that increases the ease with which a cooking appliance knob or other actuator may be rotated or actuated. 
         [0007]    More particularly, the invention is directed to an apparatus configured as a replacement knob, which can be installed in place of or in addition to an existing original equipment manufacturers (OEM) removable knob for a conventional cooking appliance to help to prevent the cooking appliance from being accidentally left on for an undesirable amount of time. The invention further provides an apparatus that automatically shuts off a cooking appliance at a specified time. 
         [0008]    In general, in an aspect, the invention provides an apparatus including a frame with an adhesive backing to secure the device to a cooking appliance, an inner heat-setting control mounted to the frame and an outer timer control mounted to the frame. The outer timer control is adapted to engage with the heat-setting control and to inhibit the heat-setting control from being turned when the timer control is in the OFF position. The device further includes a knob shaft connected to the heat-setting control that protrudes from the back of the device and may be connected to a knob or other structure that controls operation, e.g. on and off functions, of a cooking appliance. A wheel or gear is connected to the timer control and is adapted to contact or engage with a cooking appliance knob shaft or other structure that controls the cooking appliance operation so that the wheel or gear may inhibit the cooking appliance knob shaft from being turned when the timer control is in the OFF position. 
         [0009]    Capabilities and advantages of the invention may include one or more of the following. An automatic cooking appliance shutoff apparatus may be used along with or in place of an existing original equipment manufacturers (OEM) removable knob or other structure used to control the operation of a conventional cooking appliance. The shutoff apparatus may inhibit a heat-setting control from being turned, when a timer control is in the OFF position, preventing the cooking appliance from being turned on before a cooking time is set. Once the timer is set, the shutoff apparatus may enable the heat-setting control to be easily turned to the desired heat preference. When the set time has elapsed, the heat-setting control may be driven back to the OFF position, e.g. by the energy of an internal spring, to turn the cooking appliance off. 
         [0010]    The automatic cooking appliance shutoff apparatus may be constructed and arranged as a replacement knob to couple with an existing operating knob of a cooking appliance. The apparatus may be configured to accommodate a standard D-shaped cooking appliance knob shaft or a wide variety of other cooking appliance knob shaft profiles using a knob shaft insert. An appropriate knob shaft insert may enable the apparatus to engage the cooking appliance knob shaft, allowing the cooking appliance knob shaft to rotate with the apparatus away from the OFF position, when a heat-setting control of the apparatus is turned. An adhesive backing may create a mechanical base or foundation, holding a portion of the apparatus stable in relation to the cooking appliance and allowing the apparatus to achieve the torque needed to turn the cooking appliance knob shaft to the OFF position. The apparatus may also facilitate persons with diminished strength and manual dexterity to use a cooking appliance knob or other structure for its operation by reducing the force needed to turn such knob or structure of the appliance. 
         [0011]    The timer control and the heat-setting control of the apparatus may be marked and labeled to indicate their function, and may include text and/or graphics for setting preferences, such as temperature. The text or graphics may be large enough to make them easy to read for those persons with limited eyesight, and may be familiar to make them easy to understand by those persons with diminished mental capacities. The angular placement of text or graphics may be the same as the most prevalent text scheme appearing on a cooking appliance knob or other structures for operation of the cooking appliance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1A  is a front perspective view of an exemplary apparatus according to the invention; 
           [0013]      FIG. 1B  is a back perspective view of the apparatus shown in  FIG. 1A ; 
           [0014]      FIG. 2  is a perspective view of the apparatus shown in  FIG. 1  to be coupled to a knob shaft of an existing operation knob or structure of a cooking apparatus; 
           [0015]      FIG. 3  is a cross-sectional view of the apparatus shown in  FIGS. 1A and 1B  and  FIG. 2  during one stage of its operation; 
           [0016]      FIG. 4A  is a cross-sectional view of the apparatus shown in  FIGS. 1A and 1B  and  FIG. 2  during another stage of its operation; 
           [0017]      FIG. 4B  is a cross-sectional view of the apparatus shown in  FIGS. 3 and 4A ; 
           [0018]      FIG. 5  is a cross-sectional view of the apparatus shown in  FIGS. 1A and 1B  and  FIG. 2  during a further stage of operation; 
           [0019]      FIG. 6A  is a front perspective view of another exemplary apparatus according to the invention; 
           [0020]      FIG. 6B  is a back perspective view of the apparatus shown in  FIG. 6A ; 
           [0021]      FIG. 7  is a perspective view of the apparatus shown in  FIGS. 6A and 6B  mounted to an oven control panel; 
           [0022]      FIG. 8  is a perspective view of the apparatus shown in  FIGS. 6A and 6B  and  FIG. 7  with electronic controls; and 
           [0023]      FIG. 9  is a perspective view of a further apparatus according to the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Referring to  FIGS. 1A and 1B , in an aspect, the invention provides an automatic cooking appliance shutoff apparatus  10  constructed and arranged as a replacement knob for installing in place of a conventional OEM removable knob or other actuator of a conventional cooking appliance. The replacement knob  10  includes a frame  21 , an outer timer control  12 , an inner heat-setting control  14 , and a knob shaft  16 . The timer control  12  is mounted to the frame  21  such that it can pivot or rotate in relation to the frame  21 . A heat-setting control  14  is operatively connected to the timer control  12  and moveable in relation to both the frame  21  and the timer control  12 . 
         [0025]    The replacement knob  10  adheres or is otherwise affixed to a cooking appliance, e.g., its control panel using an adhesive backing  22  or other means on the frame  21 . The adhesive backing  22  or other means on the frame  21  creates a mechanical base or foundation, holding a portion of the replacement knob  10  stable in relation to a cooking appliance and allowing the replacement knob  10  to achieve the torque needed to turn the knob shaft  16  back to the OFF position, e.g. from an ON position. 
         [0026]    The timer control  12  and the heat-setting control  14  may be marked and labeled to indicate their function, and may include text and/or graphics  18  for highlighting preferences, such as temperature. The text and/or graphics  18  may be large enough to make them easy to read for those with limited eyesight, and may be common to make the text or graphics  18  easy to understand by those with diminished mental capacities. The angular placement of the text or graphics  18  may be the same as the most prevalent text scheme appearing on cooking appliance knobs. 
         [0027]    Referring to  FIG. 2 , and with further reference to  FIGS. 1A and 1B , the knob shaft  16  is connected to the heat-setting control  14  and protrudes from the back of the replacement knob  10 . The knob shaft  16  is configured to connect to an appliance knob shaft  30  or other structure that is configured and adapted to help to control the operation, e.g., setting temperature and/or turning operation ON or OFF, of a cooking appliance. In one embodiment, the replacement knob  10  may accommodate a standard D-shaped cooking appliance knob shaft  30  or a wide variety of other cooking appliance knob shaft profiles using a knob shaft insert  20 , shown in  FIG. 1A . The knob shaft insert  20  fits inside and engages with the knob shaft  16  of the replacement knob  10 . The appropriate knob shaft insert  20  may enable the knob shaft  16  to engage a cooking appliance knob shaft  30 , allowing the cooking appliance knob shaft  30  to rotate with the knob shaft  16 , e.g., away from an OFF position when the heat-setting control  14  is turned. 
         [0028]    The timer control  12  inhibits the heat-setting control  14  from being turned when the timer control  12  is in the OFF position. Referring to  FIG. 3 , when the timer control  14  is in the OFF position, a cam  40  along an inner surface  41  of the timer control  12  depresses a cam follower  42 . By depressing the cam follower  42 , the cam  40  causes the cam follower  42  to engage into a recess  44  on a circumference of the heat-setting control  14 . Engagement of the cam follower  42  into the recess  44  causes the cam follower  42  to inhibit the heat-setting control  14  from turning. 
         [0029]    Referring to  FIGS. 4A and 4B , turning the timer control  12  to set a cooking time requires compressing a spring  55 , generally disposed in the apparatus to operatively couple with the timer control  12 . The timer control  12  is turned in a counterclockwise motion, as shown by arrow  57 , shown in  FIG. 4A , against the resistance of the spring  55 . Turning the timer control  12  stores energy in the spring  55 , which allows the timer to wind down as the set time elapses. 
         [0030]    The cam  40  along the inner surface  41  of the timer control  12  rotates with the timer control  12  on the axis  59 , shown in  FIG. 4A . When the timer control  12  is turned in a counterclockwise motion, as shown by an arrow  57  in  FIG. 4A , the cam  40  rotates in the same counterclockwise motion. This counterclockwise rotation causes the cam  40  to move away from the cam follower  42 . As the cam  40  moves away, the cam follower  42  moves from the cam  40  to the cam barrel  53 . By moving to the cam barrel  53 , the cam follower  42  moves outward, away from the heat-setting control  14 , and the cam follower  42  disengages from the recess  44  in the heat-setting control  14 . 
         [0031]    Once the cam follower  42  has disengaged from the recess  44  in the heat-setting control  14 , the heat-setting control  14  can now be turned clockwise, as shown by an arrow  52  in  FIGS. 4A and 4B . A toothed pawl  54  is operatively connected to the cam follower  42  such that movement of the cam follower  42  onto the cam  40  and off of the cam  40  pivots a toothed pawl  54 . When the cam follower  42  moves outward to the cam barrel  53 , the toothed pawl  54  is pivoted against a toothed wheel  48 . The toothed wheel  48  is connected to the circumference of the heat-setting control  14 . When the heat-setting control  14  is turned, compliance provided by the toothed pawl&#39;s  54  connection to the cam follower  42  enables the reverse inclined teeth  47  on the toothed wheel  48  to slip past the toothed pawl  54 . 
         [0032]    The level of heat may be set by turning the heat-setting control  14  clockwise, as shown by an arrow  52  in  FIGS. 4A and 4B , against pressure from spring  50 . Turning the heat-setting control  14  loads the internal spring  50  with the force necessary to return the heat-setting control  14  to its OFF setting. As the heat-setting control  14  moves in a clockwise position, as shown by an arrow  52  in  FIGS. 4A and 4B , the toothed wheel  48  moves against the pawl  54  and the pawl  54  floats up the ramps of the reverse inclined teeth  74 . When the heat-setting control  14  is set to a preferred heat setting, the pawl  54  engages with the reverse inclined teeth  47 . The engagement of the pawl  54  and the reverse inclined teeth  74  on the toothed wheel  48  prevent the heat-setting control  14  from turning. The heat-setting control  14  cannot return to its OFF position until the pawl  54  is removed from its engagement with the toothed wheel  48 . 
         [0033]    Referring to  FIG. 5 , after the timer control  12  is set to a desired time, the timer control  12  rotates clockwise, as shown by an arrow  61  in  FIG. 5 , as the timer control  12  times down to the end of a cycle. As part of the timer control  12 , the cam  40  also travels clockwise during this time, as shown by an arrow  61  in  FIG. 5 . As the cam  40  travels clockwise, the leading ramp  63  of the cam  40  encounters the cam follower  42 . The leading ramp  63  of the cam  40  starts to move the cam follower  42  toward the heat-setting control  14 . As the cam follower  42  is moved toward the heat-setting control  14 , the pawl  54  is pivoted away from the toothed wheel  48 . This causes the pawl  54  to disengage from the reverse inclined teeth  74  on the toothed wheel  48  of the heat-setting control  14 . 
         [0034]    Released from the pawl  54 , the heat-setting control  14  is driven back to the OFF position by the energy of the internal spring  50 . As the heat-setting control  14  turns back to the OFF position, the knob shaft  16 , connected to the heat-setting control  14  and coupled with appliance knob shaft  30 , is also returned to the OFF position. With the heat-setting control  14  returned to the OFF position as the timer control  12  returns to the OFF position, the cam follower  42  is driven onto the highest ramp of the cam  40 . This forces the cam follower  42  to engage into the recess  44  on the circumference of the heat-setting control  14 . Engagement of the cam follower  42  into the recess  44  causes the cam follower  42  to inhibit the heat-setting control  14  from turning and locks the heat-setting control  14  until the timer control  12  is used again. 
         [0035]    Referring to  FIGS. 6A-7 , another embodiment of the invention provides a knob-turning apparatus  70  including a frame  71 , a friction wheel  72  and a timer control  80 . The timer control  80  is mounted to the frame  71  such that it can pivot or rotate in relation to the frame  71 . The friction wheel  72  is operatively connected to the timer control  80  and moveable in relation to both the frame  71  and the timer control  80 . The knob-turning apparatus  70  is adhered to a cooking appliance control panel  90 , shown in  FIG. 7 , by an adhesive backing  76  on the frame  71 . The adhesive backing  76  holds the knob turning apparatus  70  stable with relation to the cooking appliance itself. The adhesive backing  76  also provides stability for operation and allows the knob-turning apparatus  70  to achieve the torque needed to turn the OEM cooking appliance knob  92  back to the OFF position. 
         [0036]    Turning the timer control  80  to set a cooking time requires compressing the spring of a mechanical kitchen timer mechanism. The spring is generally disposed in the apparatus  70  to operatively couple with the timer control  80 . The timer control  80  is turned against the resistance of the spring. Turning the timer control  80  stores energy in the spring, which allows the timer to wind down. The mechanical kitchen timer mechanism in the knob-turning apparatus  70  is connected to a friction wheel  72 . The friction wheel  72  is mounted to the cooking appliance control panel  90  such that the friction wheel  72  is in contact with either the outer edge of the OEM cooking appliance knob  92  or the cooking appliance knob shaft  30 , as shown in  FIG. 2 . The contact between the friction wheel  72  and either the OEM cooking appliance knob  92  or the cooking appliance knob shaft  30  is such that it may prevent the OEM cooking appliance knob  92  from turning. 
         [0037]    In an additional embodiment of the knob-turning apparatus  70 , a frictional or gear component around an outer diameter  94  of the OEM cooking appliance knob  92  may engage with a mating friction wheel  72  or gear wheel on the knob-turning apparatus  70 . Further frictional grip can be achieved through application of a circumferential adhesive strip to the outer diameter  94  of the OEM cooking appliance knob  92 . 
         [0038]    The knob-turning apparatus  70  includes an engaged rotating gear attached to a wound-up clock spring that prevents the friction wheel  72  from being turned when the timer control  80  is set to the OFF position. Contact between the friction wheel  72  and the OEM cooking appliance knob  92  may prevent the OEM cooking appliance knob  92  from being turned when the friction wheel  72  is not free to turn. Therefore, when the timer control  80  is set to the off position, the OEM cooking appliance knob  92  may not be turned. When the timer control  80  is set to any position other than the OFF position, the rotating gear is disengaged, enabling the friction wheel  72  and OEM cooking appliance knob  92  to turn. 
         [0039]    Force is stored in a clock spring when the timer control  80  is turned away from the OFF position. When the timer control  80  returns to the OFF position, the rotating gear re-engages the friction wheel  72  and the clock spring&#39;s energy is released, rotating the friction wheel  72  such that the OEM cooking appliance knob  92  returns to the OFF position. 
         [0040]    In an embodiment of the invention, the friction wheel  72  may reduce the force needed to turn the OEM cooking appliance knob  92  when the timer is not set to the OFF position by using an opposing clock spring. The opposing clock spring may apply a torque to the friction wheel  72  that is slightly less than the torque needed to turn the OEM cooking appliance knob  92 . As the OEM cooking appliance knob  92  is turned, the friction wheel  72  turns easily. When the timer control  80  returns to the OFF position, the rotating gear re-engages the friction wheel  72  and the primary clock spring&#39;s energy is released, turning the friction wheel  72  such that the OEM cooking appliance knob  92  turns to the OFF position. 
         [0041]    The timer control  80  may be marked and labeled to indicate its function, and may include text and/or graphics  74  for highlighting the time. The text and/or graphics  74  may be large enough to make them easy to read for persons with limited eyesight, and may be common to make the text or graphics  18  easy to understand by persons with diminished mental capacities. The angular placement of the text or graphics  18  may be the same as the most prevalent text scheme appearing on cooking appliance knobs. 
         [0042]    Referring to  FIG. 8 , and with further reference to  FIGS. 1A-7 , an embodiment of the invention provides an electronic knob-turning apparatus  100  including a frame  101 , timer buttons  104 , a display of time remaining  102 , and an off button  106  to reset the timer to OFF. The timer buttons  104 , the display of time remaining  102 , and the off button  106  are connected to the frame  101  and are located adjacent to each other. The frame  101  may be adhered to a cooking appliance control panel using an adhesive backing on the frame  101 . 
         [0043]    In another embodiment of the replacement knob  10 , shown in  FIGS. 1A-5 , an electronic timer may replace the manual timer control  12 . The electronic timer relays user input through an electronic interface to a small motor, which is attached to the cam barrel  53 . Manual pressure on the timer buttons  104  may set the time, which is displayed on the display of time remaining  102 . When the time is set, a motor rotates the cam  40  away from the OFF position. By rotating the cam  40  away from the OFF position, the cam follower  42  moves off the cam  40  and moves to the outer surface of the cam barrel  53 . This movement off the cam  40  disengages the cam follower  42  from the recess  44  in the heat-setting control  14 . Once the cam follower  42  is disengaged from the recess  44 , the heat-setting control  14  is free to turn. Turning the heat-setting control  14  loads an internal spring  55  such that it can return the heat-setting control  14  to its OFF position. 
         [0044]    When the time expires, the electronics relay a signal to the motor, turning the cam  40  back to its original OFF position. This enables the leading ramp of the cam  40  to depress the cam follower  42 . Depressing the cam follower  42  lifts the pawl  54  out of its engagement with the toothed wheel  48 , causing the heat-setting control  14  to be driven back to the OFF position by the energy of the internal spring  50 . Once the cam  40  is back to its OFF position, the motor takes a stable position. A visual or acoustical signal or alarm may be activated in conjunction with this action. 
         [0045]    Referring to  FIG. 8 , and with further reference to  FIGS. 6A-7 , in another embodiment of the knob-turning apparatus  70 , an electronic timer may be used to relay user input through an electronic interface to a small motor, which is attached to a friction wheel  72 . The friction wheel  72  is in contact with the side of the OEM cooking appliance knob  92  or attached directly to the cooking appliance knob shaft  30 . The friction wheel exerts a force against the OEM cooking appliance knob  92  that may prevent or resist turning of the OEM cooking appliance knob  92  when the timer is set to OFF. When the timer is set to some number greater than zero, the user is free to turn the OEM cooking appliance knob  92 . Once the time expires, the electronics relay a signal to the motor, turning the OEM cooking appliance knob  92  until a sensor receives a signal that the torque is high enough to indicate the OEM cooking appliance knob  92  has arrived at the OFF position. At this point, the motor stops turning the friction wheel  72  and takes a stable position. A visual or acoustical signal or alarm may be activated in conjunction with this action. 
         [0046]    An electronic embodiment may also include input to set heat, and the motor may turn the OEM cooking appliance knob  92  to the appropriate heat level for the user. If the motor can set the heat level, the OEM cooking appliance knob  92  may be programmed to be set to a certain heat level for a specified amount of time, and then changed to a different heat level, accommodating more complicated recipes, or the ability to automatically keep food warm for a period of time after it is done cooking. Also, the motor may reduce the torque needed to turn the OEM cooking appliance knob  92 . 
         [0047]    Referring to  FIG. 9 , and with further reference to FIGS.  2  and  6 A- 7 , another embodiment of the knob turning apparatus  70  is a knob-turning apparatus  110 , which includes an extended portion  112  that engages with the cooking appliance knob shaft  30 . To install the knob-turning apparatus  110 , the OEM cooking appliance knob  92  is removed and the knob-turning apparatus  110  is placed around the cooking appliance knob shaft  30 . The cooking appliance knob shaft  30  extends through a hole  114  in the extended portion  112  of the knob-turning apparatus  110 . The cooking appliance knob shaft  30  engages with the rotating gear  116  in the extended portion  112 . The hole  114  may accommodate a standard D-shaped cooking appliance knob shaft  30  or a wide variety of other cooking appliance knob shaft profiles. 
         [0048]    The knob-turning apparatus  110  is adhered to the cooking appliance control panel  90  using an adhesive backing, and the OEM cooking appliance knob  92  is placed back onto the cooking appliance knob shaft  30 , disposed further away from the control panel  90 . A gear train located inside the extended portion  112  engages with the rotating gear  116  to prevent the cooking appliance knob shaft  30  from turning when the timer control is set to the OFF position, and turns the cooking appliance knob shaft  30  back to the OFF position when the time has expired. When the timer control  118  is set, the OEM cooking appliance knob  92  may be turned, rotating the cooking appliance knob shaft  30  and turning on the cooking appliance. 
         [0049]    Having described at least one illustrative embodiment of the invention, various alterations, modifications and improvements will readily occur to those skilled in the art. Such alterations, modifications and improvements are intended to be within the scope and spirit of the invention. Accordingly, the foregoing description is by way of example only and is not intended as limiting. The invention&#39;s limit is defined only in the following claims and the equivalents thereto.