Abstract:
A cooking device disposable on a horizontal surface. The cooking device includes a support mechanism that is movable by a drive, in a direction substantially vertical to the surface, between an operating position and an inactive position. The cooking device also has a heating unit disposed on the support mechanism and a food tray disposed on the support mechanism. The food tray and heating unit are held on the support mechanism such that the food tray and heating unit are movable relative to one another. In an inactive position of the support mechanism, the food tray has a height position that is lower than a height position of the surface.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Priority is claimed to German patent application DE 10 2007 038 040.4, filed Aug. 10, 2007, which is hereby incorporated by reference herein. 
     FIELD 
     The invention relates to a cooking device for arrangement on an essentially horizontal work surface. 
     BACKGROUND 
     German utility model DE 296 10 240 U1 describes a cooking device known in the technical world as a “salamander” for food that serves to brown, caramelize, grill, toast, broil, heat and keep it warm, etc. 
     As a refinement of the salamander described, for example, in German utility model DE 296 10 240 U1, German patent application DE 103 54 127 A1 describes a special positioning of the heating device on the support mechanism. The height of the heating device on the support mechanism can be adjusted whereas the tray is attached thereto in a fixed position, so that the vertical distance between the tray for the food and the heating device can be set as desired. 
     Moreover, German patent application DE 26 57 746 A1 shows a cooking device configured as an oven for arrangement on an essentially horizontal work surface, comprising a support mechanism configured as an oven chamber, on which several trays configured as metal insert racks for food and a heating unit formed by the ceiling of the oven chamber and by a broiling element are arranged. The support mechanism can be moved by means of a manual or automatic drive essentially vertically to the work surface, back and forth between an inactive position and an operating position, whereby, in the operating position, at least the tray is at a lower height position than the top of the work surface. 
     SUMMARY 
     An aspect of the present invention is to provide a cooking device that requires a small amount of storage space when it is not in use, in other words, when it is in the inactive position. 
     In an embodiment, the present invention provides a cooking device disposable on a horizontal surface. The cooking device includes a support mechanism that is movable by a drive, in a direction substantially vertical to the surface, between an operating position and an inactive position. The cooking device also has a heating unit disposed on the support mechanism and a food tray disposed on the support mechanism. The food tray and heating unit are held on the support mechanism such that the food tray and heating unit are movable relative to one another. In an inactive position of the support mechanism, the food tray has a height position that is lower than a height position of the surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An embodiment of the invention is explained in detail below and depicted schematically in the drawings, in which: 
         FIG. 1  is a perspective top view of a cooking device according to the invention, with the support mechanism in the inactive position; 
         FIG. 2  shows the cooking device of  FIG. 1  in a similar depiction and with the support mechanism in an operating position; 
         FIG. 3  is a partial bottom view of the cooking device of  FIG. 2 , in the viewing direction of the heating unit; 
         FIGS. 4 to 7  show sectional side views of the cooking device of  FIG. 1 , showing different height positions of the support mechanism; and 
         FIGS. 8 to 13  show a partial depiction of the cooking device of  FIG. 1 , in the area of the support mechanism, showing different height positions, alternating between perspective and sectional views. 
     
    
    
     DETAILED DESCRIPTION 
     In addition to the small storage space when the device is not in use, the present invention provides the possibility of a cooking device that may be is kept out of sight of the user to the greatest extent possible when it is in its inactive position. This may improve the overall esthetic appearance of the area where the cooking device is set up. The cooking device can be configured in such a manner that it blends in with the rest of the kitchen or the like inconspicuously, at least when the support mechanism is in the inactive position. In particular, this may be achieved if there are cabinets underneath the work surface in which the cooking device is installed and into which it can be retracted when it is in the inactive position. As an alternative to cabinets underneath the work surface, it is likewise conceivable to use other types of enclosures for other built-in appliances, especially built-in kitchen appliances. This further takes advantage of the utilization of the available space. Alternatively, however, it would also be possible for the cooking device to have its own free-standing housing, so that it is not used in combination with a kitchen countertop or with kitchen built-in appliances or other types of enclosures. 
     In an embodiment of the present invention the tray or the heating unit may be attached vertically to the support mechanism in a fixed position. As a result, the cooking device according to the invention is realized with a particularly simple construction. 
     It is also possible for the tray and the heating unit to be moved separately from each other, for instance, by two independent electric motors. The tray and the heating unit may be detachably connected via a coupling and as a function of the height position of the support mechanism. This makes it possible to employ a single drive for the tray as well as for the heating unit. 
     In an embodiment the coupling has a latch that is pre-tensioned in the direction of the unlatching position by a spring element. As a result, the coupling has a simple and sturdy construction. 
     The relative position of the tray and of the heating unit in the inactive position, in the operating position and in the intermediate positions can be selected freely within a broad suitable range. In one embodiment the tray and the heating unit can lie against each other when the support mechanism is in the inactive position. This reduces the storage space requirement in the inactive position to a minimum, so that the space gained in this manner can be utilized for other functions or by other devices such as, for instance, other kitchen appliances. 
     In one embodiment, the height position of the support mechanism can be detected by at least one position sensor and, as a function of the measuring signals, the heater of the heating unit can be switched by an electric control unit of the cooking device. As a result, the heater can be switched on automatically, for example, when the support mechanism is moved into the operating position, and the heater can be switched off automatically, for instance, when the support mechanism is moved into the inactive position. Consequently, the actuation of operating elements such as, for instance, an ON-OFF button, is no longer absolutely necessary. 
     The drive can be freely selected over a wide suitable range in terms of its type, power and arrangement. The drive can optionally be configured as an electric drive that can be switched on by an operating element. This improves the convenience, for example, in comparison to a drive that is operated manually. 
     In an embodiment the temperature of the heating unit can be detected by a temperature sensor and, as a function of the measuring signals, the drive of the support mechanism can be switched by the electric control unit of the cooking device. This ensures, for example, that the cooking device cannot be completely lowered into a built-in cabinet in an undesired manner if the temperature of the heater and thus of the heating unit is still above a pre-specified maximum value. This markedly improves the safety of the cooking device. 
     In another embodiment the tray has a substructure and a cover plate that can be laid onto it, whereby the current path leading to the drive and to the heater is interrupted if the cover plate has not been put in place, even if the operating element is in the switched-on position. This ensures that the cooking device cannot go into operation without the cover plate onto which the food is to be placed. 
     In another embodiment, the switched-on drive can be automatically switched off as a function of the rise in current. In this manner, simple design and circuit-engineering means can effectuate, for instance, a so-called auto-reverse feature or an overload protection. 
       FIG. 1  shows a cooking device  1  according to the present invention in its installed position in a work surface  2  configured as a kitchen countertop. The cooking device  1  has an operating panel  4  with an operating element  6  configured as an operating knob that serves to switch on and off the drive  8  that is shown in greater detail in the other figures. The drive  8  is configured here as an electric drive with an electric motor. The other operating element  10  configured as an operating knob serves to set the heating power of the heater  12  that is likewise shown in greater detail in the other figures. The operating panel  4  is part of a surrounding frame  14  of the cooking device  1  in whose center the top of the heating unit  16  can be seen. As can be gleaned from  FIG. 1 , the top of the cooking device  1  and the top of the work surface  2  are almost flush with each other; all that remains is a small surrounding rim of the kind known, for example, from autonomous kitchen cooktops. The support mechanism  18  shown in greater detail in the other figures is in the inactive position. 
     When the user actuates the operating knob  6  by turning it clockwise, the support mechanism  18  travels from its inactive position shown in  FIG. 1  to an operating position as shown, for example, in  FIG. 2 . The movement of the support mechanism  18  here is triggered exclusively by turning the operating knob  6  clockwise one time and it continues, even without any further actuation of the operating knob  6 , until the maximum height position of the support mechanism  18  has been reached. Details about this will be explained on the basis of the other figures. When the operating knob  6  is turned counterclockwise during the movement into one of the operating positions, the drive  8  is switched off and the support mechanism  18  remains in the height position it had reached at that point in time. 
     A tray  20  for food has a substructure  20 . 1  shown in  FIG. 2  and a cover plate  20 . 2 , which is shown as removed in  FIG. 2 , onto which the food is to be placed. In contrast to what is shown in  FIG. 2 , movement of the support mechanism  18  may only possible at all if the cover plate  20 . 2  has been placed onto the substructure  20 . 1 . This is ensured by a solenoid switch  22  which is shown in greater detail in  FIGS. 4 to 7  and which is integrated into an electric control unit  24  of the cooking device  1  symbolically depicted in  FIG. 4 , whose mode of operation is generally known. Here, if the cover plate  20 . 2  has not been put in place, the solenoid switch  22  prevents, on the one hand, the drive  8  for the support mechanism  18  from being switched on, irrespective of whether the operating knob  6  has been actuated or not. On the other hand, if the cover plate  20 . 2  has not been put in place, said solenoid switch  22  prevents the heater  12  from being switched on by means of the operating knob  10  in the familiar manner. 
     As an extra safety feature, it is provided here in the circuit of the electric control unit  24  that, even after the cover plate  20 . 2  has been put in place, the heater  12  can only be switched on after the support mechanism  18  has been moved into the inactive position, and subsequently moved into an operating position. In the present embodiment, this also applies in the case of a power outage; in this eventuality as well, even after the power supply has been restored and even if the power is set to ON, the heater  12  is only switched on after the support mechanism  18  has once again been moved into the inactive position, and subsequently moved into an operating position. 
     Another safety function of the present embodiment consists of the fact that the operating knob  6  has to be continuously actuated in order for the support mechanism  18  to be moved into the inactive position; the user has to turn the operating knob  6  counterclockwise and has to hold it in this position against an autonomous restoring force, for instance, a spring or the like, so that the drive  8  continues to receive current. Such a function is also referred to as a dead man&#39;s switch. 
     In order to increase the convenience for users, the heater  12  is automatically switched on here when the support mechanism  18  is moved into an operating position, provided that a heating power setting has been selected by means of the operating knob  10 . 
     As can be clearly seen in  FIG. 2 , the heating device  16  in the present embodiment is attached to the support mechanism  18  in a fixed position, so that the heating device  16  is attached vertically to the support mechanism  18  in a fixed position. 
       FIG. 3  shows the heating device  16  in a bottom view in the viewing direction of the heater  12 . The heater  12  is configured here as an electric radiant heater. Fundamentally, however, other types of heaters such as, for instance, gas or halogen lamps, are likewise conceivable. For purposes of allowing better cleaning and as protection against accidental contact, the bottom of the heater  12  is covered by a cover  16 . 1 , for example, glass or ceramic, that is permeable to heat radiation. 
       FIGS. 4 to 7  show sectional side views of the cooking device  1  installed into the work surface  2 , so that the support mechanism  18  and the associated lifting mechanism are visible. 
       FIG. 4  shows the support mechanism  18  in its inactive position; the top of the cooking device  1  is almost flush with the top of the work surface  2 . As can be clearly seen in  FIG. 4 , the tray  20  with the cover plate  20 . 2  and the bottom of the heating unit  16  are essentially in contact with each other in the depicted inactive position of the support mechanism  18 . The drive  8  drives a threaded rod  26  that is shown in greater detail in  FIGS. 8 to 13 . The support mechanism  18  is joined via a sleeve  18 . 1  to the threaded rod  26  so as to transmit force, so that the rotational movement of the threaded rod  26  is converted into a translatory movement of the support mechanism  18 . In order to prevent the support mechanism  18  from tilting during movement, the support mechanism  18  is guided by two additional sleeves  18 . 2  located on two guide tubes  28 . All of the actuating elements to move the support mechanism  18  are arranged in a housing  31  of the cooking device  1 , so that it is also possible to simply arrange the cooking device  1  according to the present embodiment on a work surface  2 . In other embodiments without a housing  31 , it would only be possible to install the device into another enclosure, for instance, a kitchen cabinet underneath the counter. The broken-line arrow  24 . 1  in  FIG. 4  symbolizes the signal-transmission connection between the solenoid switch  22  and the electric control unit  24 . 
     In contrast to  FIG. 4 ,  FIGS. 5 to 7  show the cooking device  1  in an intermediate position, see  FIG. 5 , and in a possible operating position, see  FIGS. 6 and 7 . A combined observation of  FIGS. 4 to 7  clearly shows that the tray  20  and the heating unit  16  in the inactive position and even in the intermediate position, are still positioned close to each other, whereas  FIGS. 6 and 7  already show that, while the support mechanism  18  is being moved into an operating position, the heating unit  16  moves further towards the top relative to the plane of the drawing, while the tray  20  remains in the position shown in  FIG. 5 . 
       FIG. 7  shows the cooking device  1  in a sectional view, in the viewing direction of the other side of the cooking device  1  in comparison to  FIG. 6 . The position sensors  30 . 1 ,  30 . 2  and  30 . 3 , which are configured as microswitches, are likewise visible in this view. The microswitches  30 . 1  to  30 . 3  are actuated by an actuation tab  18 . 3  arranged on the support mechanism  18 . As a result, a sensor system to ascertain the position of the support mechanism  18 , namely, the height position of the support mechanism  18 , can have a simple and sturdy construction. 
     While the support mechanism  18  is being moved from the inactive position into one of the possible operating positions that can be freely selected by the user by means of the operating knob  6 , as shown in a time-lapse fashion in the sequence of  FIGS. 4 to 7 , the actuation of the position sensor  30 . 3 —in other words, of the uppermost microswitch on the plane of the drawing—by means of the actuation tab  18 . 3  causes the drive  8  that had been switched on by the operating knob  6  to be automatically switched off again; the maximum possible height position of the support mechanism  18  has been reached. 
     Due to the counterclockwise actuation of the operation knob  6  as explained in greater detail above, the drive  8  is automatically switched on again; now it turns in the opposite direction, so that the support mechanism  18  is moved from the maximum possible operating position back towards the inactive position. 
     The same applies analogously to the other possible operating positions of the support mechanism  18 . As soon as the actuation tab  18 . 3  actuates the position sensor  30 . 2 , that is to say, the middle microswitch, during the movement into the inactive position, the signal of a temperature sensor  12 . 1  that detects the temperature of the heater  12  and thus of the heating device  16  is automatically evaluated by the electric control unit  24 . In this context, also see the broken-line arrow  24 . 2  in  FIG. 7 , which symbolizes the signal-transmission connection between the temperature sensor  12 . 1  and the electric control unit  24 . If the measured temperature exceeds a pre-specified switching temperature of about 65° C. in the case here, the drive  8  is automatically switched off; the same applies for the eventuality that the temperature is the same as the switching temperature. If the temperature is below the switching temperature of about 65° C., the support mechanism  18  can be moved further towards the inactive position in the manner already described above, until the inactive position shown in  FIG. 4  is ultimately reached. In the inactive position, the actuation tab  18 . 3  actuates the lowermost microswitch, that is to say, the position sensor  30 . 1 , by means of which the drive  8  is switched off again. 
     The drive is automatically switched off if the temperature measured by the temperature sensor  12 . 1  is the same as or higher than 65° C. at the point in time when the position sensor  30 . 2  is actuated. Therefore, at higher temperatures, the support mechanism  18  cannot be moved further towards the inactive position; the top of the cover plate  20 . 2  and the bottom of the heating device  16  are at a distance of about 65 mm from each other here. The drive  8  can only be switched on again by means of the operating knob  6  once the temperature of the heater  12  has fallen below 65° C. The further course is as described above. 
     A residual heat display  32  configured as an indicator lamp situated on the operating panel  4  shows the user whether the temperature has fallen below 65° C. As soon as the temperature measured by the temperature sensor  12 . 1  is lower than 65° C., the light in the residual heat display  32  goes off. In contrast, at higher temperatures, the residual heat display  32  lights up. 
     In order to further improve the protection against an undesired lowering of the support mechanism  18 , an additional temperature sensor in the form of a temperature limiter  12 . 2  is provided here. The use of the temperature limiter  12 . 2  here offers additional protection against cable breakage since the current path of the temperature limiter  12 . 2  is closed in the normal state and when the temperature of the heating unit  16  is lower than 65° C. If a cable is broken, the current path is opened and the temperature limiter  12 . 2  acts redundantly to the temperature sensor  12 . 1  already comprehensively explained above. For the rest, the temperature limiter  12 . 2  functions analogously to the temperature sensor  12 . 1 . 
     Moreover, in the present embodiment, the electric control unit  24  evaluates the rise in current of the drive  8  for purposes of automatically controlling the drive  8  and thus moving the support mechanism  18 . For instance, if a heavy object has been placed onto the top of the heating unit  16  when the support mechanism  18  is in the inactive position, see  FIG. 4 , and if the user would like to move the support mechanism  18  to an operating position in the manner explained above, this is automatically detected by the electric control unit  24  in a manner familiar to the person skilled in the art due to a rise in the current being supplied to the motor of the drive  8  and the drive is automatically switched off. In the opposite case, in other words, if the user would like to move the support mechanism  18  from an operating position, see  FIG. 6  or  7 , into the inactive position shown in  FIG. 4 , and if due to inattentiveness, a finger or hand has been placed into the space between the tray  20  and the heating device  16 , the electric control unit  24  automatically switches off the drive  8  in an analogous manner. In the latter case, that is to say, if the drive  8  is switched off while the support mechanism  18  is being moved into the inactive position, the drive  8  is controlled by the electric unit  24  in a manner known to the person skilled in the art in such a way that the support mechanism  18  moves again a small distance in the opposite direction, in other words, towards the operating position. This is done here in that the drive  8  is switched off after the undesired rise in current has been automatically detected and is switched back on in the reverse direction of rotation for a pre-specified duration. 
     In both cases, the detection of a rise in current that exceeds a pre-specified maximum value causes the drive  8  to immediately be switched off, so that the support mechanism  18  is not moved any further. As a result, in a manner involving simple circuit-engineering means, it is possible to achieve overload protection as well as an auto-reverse feature, thus enhancing the protection against damage to persons and property. 
     The sequences of the movement of the support mechanism  18  for the present embodiment can be seen in  FIGS. 8 to 13 , which will be elaborated upon below. 
       FIG. 8  partially shows the cooking device  1  in the viewing direction of the support mechanism  18  in the inactive position, that is to say, in the position already shown in  FIGS. 1 and 4 . As already explained above, the heating unit  16  is attached to the support mechanism  18  in a fixed position, so that the heating device  16  is affixed on the support mechanism  18  in the vertical direction, in other words, in the image plane of  FIG. 9  parallel to the lengthwise edge of the drawing. The tray  20  is coupled to the support mechanism  18  via a latch  20 . 3  and thus to the heating unit  16  so as to transmit force, which can be clearly seen in  FIG. 9 . Towards this end, the support mechanism  18  has a kind of latching mechanism  18 . 4  that is configured here as a cylindrical pin and that engages with the latch  20 . 3  in the coupled state. The latch  20 . 3  is pre-tensioned in the position shown in  FIG. 9  by means of a spring element  34  configured as a spiral spring in such a way as to promote a clockwise rotational movement of the latch  20 . 3  around the axis of rotation  36 . Therefore, the latch  20 . 3  and the latching mechanism  18 . 4  form a coupling by means of which the heating device  16  and the tray  20  are detachably connected as a function of the height position of the support mechanism  18 . 
       FIGS. 10 and 11  show the cooking device  1  in a partial view in the viewing direction of the support mechanism  18  in an analogous view to  FIGS. 8 and 9  in the intermediate position between the inactive position and the operating position already shown in  FIG. 5 . 
     In this position of the support mechanism  18 , the latch  20 . 3  with a nose  20 . 3 . 1  arranged on it is at the height of an opening  31 . 1  formed in the housing  31  corresponding to the nose  20 . 3 . 1 . The latch  20 . 3  that is pre-tensioned by the spiral spring  34  moves clockwise around the axis of rotation  36 , so that the latch  20 . 3  with the nose  20 . 3 . 1  engages into the opening  31 . 1 . This rotational movement transpires concurrently with the further upward movement—relative to the image plane of FIG.  11 —of the support mechanism  18 , so that, in the meantime, the latch  20 . 3  is disengaged from the latching mechanism  18 . 4 . 
     The coupling formed by the latch  20 . 3  and the latching mechanism  18 . 4  is released; since the latch  20 . 3  is now latched to the housing  31 , the tray  20  remains fixed in its height position; also see  FIG. 5 . The heating device  16  is moved further upwards by the support mechanism  18  in the manner described above. Also see  FIGS. 6 and 7  in conjunction with  FIGS. 12 and 13 . 
     This upward movement of the heating device  16  is stopped, as already described above, either by the user by actuating the operating knob  6  or by actuating the position sensor  30 . 3  by means of the actuation tab  18 . 3 . 
     When the support mechanism  18  is moved from one of the possible operating positions to the inactive position, the sequence explained above is executed in the opposite order. The heating device  16  attached to the support mechanism  18  moves downwards in the image plane of  FIG. 13 . As soon as the support mechanism  18  has reached the height position according to  FIG. 11 , the latch  20 . 3  engages with the latching mechanism  18 . 4 . As the support mechanism  18  continues its downward movement, the latching mechanism  18 . 4  pulls the latch  20 . 3  against the spring force of the spiral spring  34  with the nose  20 . 3 . 1  out of the opening  31 . 1  of the housing  31 . In this process, the latch  20 . 3  is turned counterclockwise around the axis of rotation  36 . The coupling of the tray  20  and the heating  16  formed by the latch  20 . 3  and the latching mechanism  18 . 4  is restored. Starting from this height position of the support mechanism  18 , both the heating device  16  and the tray  20  are moved jointly further downwards. 
     As already explained, this downward movement is likewise stopped, either when the user actuates the operating knob  6  or when the position sensor  30 . 1  is actuated by means of the actuation tab  18 . 3 . 
     The invention is not limited to the present embodiment. For instance, other suitable couplings known to the person skilled in the art are likewise conceivable for purposes of coupling the tray to the heating unit as a function of the height position of the support mechanism. As an alternative to the proposed coupling, it is also conceivable for the support mechanism to be configured in two parts, whereby one part holds the tray and the other part holds the heating device, and the height of both parts of the support mechanism can be adjusted by separate drives, in other words, they can be moved in the vertical direction. The type and arrangement of the employed position and temperature sensors can also be freely selected over a wide range. The same applies to the spring element, whose type, spring constant and arrangement can be freely selected over a wide range. Fundamentally, instead of the electric drive employed here, other automatic or even manual drives known to the person skilled in the art are likewise conceivable.