Abstract:
The disclosure relates to a door opening mechanism for a cooking device. The device includes a body defining a cooking chamber and a door operatively mounted to the body to provide access to the cooking chamber while maintaining a closed insulated barrier while in use. A sensor is mounted the body for providing a signal to retaining member when activated. A retaining member is mounted within the body to hold a latch attached to the door. The latch is released from the retaining member when a signal is provided by the sensor to the actuator retaining member that provides a positive drive force to release the latch and open the door.

Description:
BACKGROUND OF THE DISCLOSURE 
       [0001]    The present disclosure relates to an actuated door opening mechanism, and more particularly an actuated door opening mechanism for a cooking appliance or device operated by a touch sensor device. 
         [0002]    In conventional cooking appliances such as microwave ovens, a cooking chamber is provided to house an associated food product while having a closed or substantially sealed barrier. The sealed barrier is insulated and prevents the unwanted leakage of microwave energy or heat to the surrounding atmosphere while the cooking appliance is in use. The sealed barrier of the cooking chamber is oriented to allow a user or homeowner to have sufficient access to the associated food product that is cooked within the appliance. 
         [0003]    Generally, access to the cooking chamber is provided by a door that has certain structural and functional attributes necessary to maintain a sealed barrier. These characteristics include providing insulation within the door and body of the cooking device, as well as having geometrically interconnected contoured edges aligned between the body and the door when closed. Hinges are provided about the door and have sufficient strength or reinforcement to allow for smooth operation and to prevent binding during opening and closing movements. The hinges are preferably located outside of the cooking chamber and do not impinge upon the sealed barrier. The door remains closed during use of the cooking device to prevent unwanted leakage of microwave energy or heat loss. 
         [0004]    It is also known for cooking devices to include an interlock switch that provides a signal to the cooking device indicating when the door is in the closed position. When the door is opened, the interlock switch provides a signal to the cooking device indicating to shut off power supplied to the cooking chamber simultaneously with the opening of the door. This safety feature is generally known within the prior art and prevents the unwanted leakage of microwave energy from the cooking chamber. 
         [0005]    Additionally, cooking devices include an opening mechanism to allow an associated user to open a securely closed door for access to the cooking chamber. There are many different types of door opening mechanisms available that are known within the prior art. Opening mechanisms are designed to rely upon an applied force supplied by the associated user to disengage a latch from a retaining member located within a guide hole or aperture contained by the body of the cooking device. Retaining members are known to be comprised of an arrangement of springs, guide members, and pivot joints within the body that receive and hold a latch to securely close the door to the body or housing of the cooking device. 
         [0006]    Many cooking devices use a handle operatively mounted to an exterior surface of the door to manipulate the latch and thereby engage or disengage the door from the body. Other devices use a statically mounted handle whereby the latch is manipulated by a spring force coupled with an angular shaped or hooked portion of the latch to engage or disengage the door from the retaining member. However, a predetermined force must be applied to the handle by the user to overcome the spring force and effectively open and close the door of these cooking devices. 
         [0007]    It is also known in the prior art to provide a push button or plunger type opening mechanism. Typical push buttons are mounted to the face of the cooking device and arranged adjacent to the door to manipulate the springs, guide members, etc., of the retaining member. However, push buttons also require an associated force provided by a user to manipulate the retaining member which disengages the latch and opens the door. 
         [0008]    The associated force must be substantial enough to displace the latch from the arrangement within the body of the cooking device. The required force required to open/close the door varies as a function of the retaining member orientation and spring force constants, as well as a number of possible geometric design arrangements. Mechanical bindings and internal guide member friction forces also affect the amount of associated force necessary to displace the retainer and disengage the latch. Additionally, the position of the user relative to the cooking device. The user may be holding a food dish or tray and be unable to supply the required force to overcome the spring or latching force to open or close the door. 
         [0009]    For the foregoing reasons, there is a need to provide an opening mechanism for a cooking device that does not require a substantial associated force to open the door for access to the cooking chamber. 
       SUMMARY 
       [0010]    The present disclosure relates to a touch sensor used as an opening mechanism that allows a user to open the door of a cooking device without applying a large opening or closing force. 
         [0011]    A preferred opening mechanism includes a body defining a cooking chamber and a door operatively mounted to the body to provide access to the cooking chamber while maintaining a closed barrier while in use. A touch sensor or tactile switch is mounted substantially flush to the exterior of the body and provides a signal to an actuator retaining member when engaged by an associated finger or dielectric object. The touch sensor/tactile switch comprises a substantially planar boundary area that can detect the presence of an associated finger or dielectric object within the boundary area. An actuator retaining member is located within the body of the cooking device that operatively receives and holds the latch. The latch engages the actuator retaining member while the door is in a closed position and thereby maintains a sealed barrier for the cooking chamber. The latch is released from the actuator retaining member when a signal is provided by the touch sensor. Further, the actuator retaining member provides a positive drive force to the latch and places the door in the open position without the use of an associated substantial force. 
         [0012]    Touch sensor or tactile switch systems and displays coupled with a mechanism capable of providing a positive drive force eliminate the need for a substantial force applied to handles, mechanical buttons, keypads, keyboards, and pointing devices. For example, a user can carry out a sequence of instructions by touching an on-display touch screen to generate a signal to operate the appropriate function. The actuator retaining member also advantageously supplies a positive drive force to effectively disengage the latch from the retainer and thereby open the door. 
         [0013]    A preferred embodiment includes a door opening mechanism for a cooking device that has a touch sensor/tactile switch and an actuator. An elongated bracket is provided within the door subject to a spring force and connects to a pawl and latch which extend outwardly towards the body to engage an actuator and retaining member, respectively located within the body. The touch sensor/tactile switch provides a signal to the actuator that supplies a positive drive force to the pawl thereby displacing the elongated bracket subject to the spring force and disengaging the latch from the retaining member and thereby opening the door without the use of substantial force. 
         [0014]    Another preferred embodiment uses a capacitive touch screen as the touch sensor. The capacitive touch screen is responsive to an input or a conductive object such as a finger or a dielectric object. The capacitive touch screen measures capacitance caused by the touch, and uses the measured capacitance to determine touch presence. The touch screen recognizes the difference in capacitance and provides an output signal indicating touch occurrence. 
         [0015]    Still another preferred embodiment uses a resistive touch screen as the touch sensor. The resistive touch screen includes two thin, electrically conductive layers separated by a narrow gap. The resistive touch screen registers the touch when the two conductive layers come into contact which causes a change in the electrical current and generates the signal. 
         [0016]    Yet another preferred embodiment provides feedback to a user when a haptic or touch event is acknowledged on the touch sensor. The feedback can be visual, audible, or physical, or any combination of the three, to verify that a touch has occurred. 
         [0017]    Still other benefits and advantages of the disclosure will become apparent upon reading and understanding the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is an isometric view of the microwave with the door in the open position. 
           [0019]      FIG. 2  is an enlarged view of the microwave latching arrangement. 
           [0020]      FIG. 3  is a side view partially in cross-section of the microwave with the door in the closed position. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    Referring to  FIG. 1 , there is shown a speedcooking appliance or microwave oven  100  comprising an outer housing, casing or body  110  enclosing a cooking chamber  120 . A front opening of the cooking chamber  120  is closed by a door  130  hinged along one edge or end  140  and having a handle  150  at the opposite edge or end  160 . A plurality of latches  170 ,  180  and a pawl  190  are positioned about the opposite end  160  of the door  130  and extend from a rear face of the door toward the body. The latches  170 ,  180  and pawl  190  are operatively located to be received through the respective slots  200 ,  210 ,  220  arranged in the face  230  of the cooking chamber  120  surrounding the front opening. The latches  170 ,  180  selectively lock the door in the closed position and provide a substantially sealed barrier about the cooking chamber  120  to prevent unwanted energy loss while the microwave oven  100  is activated. 
         [0022]    The face  230  of the microwave  100  preferably has a control panel  240  for the general control of the microwave  100  and to select the desired mode of cooking, a timer, a display, clock, etc. A touch sensor or tactile switch  250  is provided on a portion of the face  230  to allow an associated user to open the door  130  by bringing a finger or other dielectric object into contact or proximity with the touch sensor. The touch sensor  250  is generally mounted flush along the face  230  and includes a boundary area  260  that is generally rectangular but may also be arranged in any practical geometric shape that can be adapted to encompass any available area based on the design criteria of the face  230 . There are several types of sensor technologies that are known within the prior art and this disclosure is not limited in this regard. Known technologies include the use of capacitive, resistive, surface wave, strain gauge, optical imaging, and infrared technologies amongst others that can sense the finger or dielectric object in contact with or closely adjacent with the touch sensor. Tactile switches can be activated by either buttons or through a protective film. Of course, touch sensors and tactile switches are preferred embodiments but the present disclosure should not be limited to these arrangements. 
         [0023]    With additional reference to  FIG. 2 , there is shown an actuator retaining member  270  that preferably includes a bracket  275  and an actuator  370  located within the body  110  of the microwave oven  100 . The representative latch  170  penetrates the slot  200  and engages the bracket  275  that is configured or oriented to hold the latch  170  and lock the door in the closed position. The bracket  275  is formed of a structurally rigid material such as plastic or metal that can be shaped to provide an inclined surface or plate  280  that allows a leading face of the latch to ride over until an undercut region of the latch  170  physically engages the bracket and retains the latch  170  within a cavity  290  that communicates rearwardly of the slot  200 . 
         [0024]    More particularly, the latch  170  has a hooked portion  340  that is adapted to engage the bracket  270  inwardly of the inclined plane  280  as the latch is advanced through the slot  200 , slides over the inclined surface  280 , and into the cavity  290 . The hooked portion  340  extends past a pinnacle or shoulder  350  of the inclined plate  280  where a segment of the latch is received through an opening  360  provided within the cavity  290 . The hooked portion  340  is shaped to engage the bracket  270  to lock the door in the closed position. 
         [0025]    Once the door  130  is in the process of being closed by an associated user, the hooked portion  340  of the latch  170  engages the base  310  of the inclined surface  280  and forces the latch  170  to shift in an upward direction while maintaining a substantially perpendicular orientation in relation to the door  130 . An elongated bracket  320  is mounted within the door  130  and interconnects the latch  170  to a plurality of similar latches to allow for the uniform motion of the latches engaging similar brackets. The elongated bracket  320  is biased by a spring force represented by reference numeral  330  located within the door  130  and urges the latch over the pinnacle  350  of the inclined surface thereby locking the door  130  in the closed position subject to overcoming the predetermined spring force  330 . 
         [0026]    An actuator  370  is mounted to the bracket  270  and oriented to physically abut or engage the hooked portion  340  when the door is in the closed position. The actuator  370  may include any conventional automated mechanism including but not limited to a solenoid valve, a rotating cam, or linear drive. As shown in  FIG. 2 , the actuator  370  includes a drive member or actuating pin  380  that is operatively connected to the drive base or solenoid  390  and positioned on the bracket  275 . The actuator means  370  is electrically interconnected with the touch sensor  250  to receive an open signal provided in the form of a valid touch on the touch sensor. In response to the touch sensor providing a signal, the drive pin is extended from the solenoid base  390  to physically engage the hooked portion  340  and urge or force the latch  170  upwardly over the shoulder  350  to disengage the latch from the inclined plate  280 . The hooked portion is shaped to interact with the inclined plate  280  in such a way that once the latch  170  is disengaged from the opening  360  and overcomes the spring force  330 , the same spring force urges the latch to proceed toward the inclined surface  280  and thereby opens the door. The shape of the hooked portion  340  interacting with the inclined surface  280  and subject to constant spring force  330  effectively urges the hooked portion  340  over the pinnacle  350  and thereby opens the door  130 . 
         [0027]      FIG. 2  shows the actuator  370  oriented in a generally parallel orientation relative to the door  130 . However, the driving mechanism  370 , bracket  275 , cavity  290  and hooked portion  340  may be oriented in such a way that allows the actuator  370  to be mounted in a different angular relation relative to the bracket and hooked portion without departing from the scope and intent of the present disclosure. 
         [0028]      FIG. 3  shows a preferred embodiment of the present disclosure whereby the addition of a pawl  190  is provided. The microwave oven  100  is depicted to have two retaining members  400 ,  410  mounted within the body  110 . Specifically, retaining member  400  is operatively associated with slot  200  and interacts with latch  170  while retaining member  410  is operatively associated with slot  210  and interacts with latch  180 . The use of multiple retaining members provides increased locking force to provide a secure closed position. 
         [0029]    Retaining members  400 ,  410  include interlock switches  420 ,  430  mounted to respective brackets  440 ,  450 . Interlock switches are generally well known in the prior art and function as a shut off switch linked to the operation of the microwave oven  100 . The brackets  440 ,  450  have a substantially similar arrangement as bracket  275  from  FIG. 2  however an interlock switch is provided in place of the actuator. 
         [0030]    The interlock switches  420 ,  430  have actuating arms  460 ,  470 , respectively, which are used utilized in such a way that depression of the actuating arms  460 ,  470  by latches  170 ,  180  also depress projections or buttons  480 ,  490  that activate the interlock switches  420 ,  430 . The actuating arms  460 ,  470  are located adjacent to inclined plates  500 ,  510  in such a way that the segments  520 ,  530  of the latches  170 ,  180  protrude though openings  540 ,  550  of cavities  560 ,  570  and depress the respective actuating arms  460 ,  470  when the door  130  is in the closed position. When depressed, the interlock switches  420 ,  430  provide a signal indicating that the door is closed thereby allowing the operation of the microwave oven  100 . Release of the actuating arms  460 ,  470  releases the buttons  480 ,  490  and, in turn, deactivates the interlock switches  420 ,  430  to shut off operation of the microwave oven. 
         [0031]    Pawl  190  is mounted to elongated bracket  320  in a substantially parallel arrangement to latches  170 ,  180 . The elongated bracket  320  provides uniform motion of latches  170 ,  180  and pawl  190  subject to the biasing spring force  330  within the door  130 . The pawl  190  selectively penetrates slot  220  and is aligned to engage actuator  580 . The actuator  580  is mounted within the body  110  of the microwave oven  100  and preferably arranged between retaining members  400 ,  410  for selective operative interaction of head portion  590  of the pawl  190  with the actuator  580 . 
         [0032]    The actuator  580  includes a drive pin  600  that is operatively connected to the solenoid or drive base  610 . The actuator  580  is electrically interconnected with the touch sensor  250  to receive an open signal from the touch sensor  250 . In response to the signal, the drive pin  600  is extended from the drive base  610  to engage the head portion  590  and move the pawl  190  in an upward, release direction. The actuator  580  drives the pawl  190  a predetermined distance to raise the elongated bracket  320  and displace the latches  170 ,  180  upwardly to a disengaged position relative to inclined surfaces  500 ,  510  and open the door of the microwave oven. 
         [0033]    The actuator  580  may use alternative drive mechanisms including but not limited to a solenoid, rotating cam, rack and gear linear drive, etc. In addition, the touch sensor  250  may also provide feedback or a haptic effect indicating to an associated user that the sensor has been actuated. For example, the feedback may include a physical, visual or audible notification. 
         [0034]    The disclosure has been described with respect to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the disclosure be construed as including such modifications and alteration in so far as they come within the scope of the appended claims or the equivalents thereof.