Abstract:
A control unit, particularly for a cooking appliance, containing at least one depressible knob via which at least one switch can be actuated by an outward motion of the knob. The aim is to provide a control unit and cooking appliance of the aforementioned type, in which additional functions can be versatilely integrated in a structurally simple manner in a depressible knob without limiting the rotating motion of the knob. To this end, a blocking unit prevents the knob, in at least one rotating position, from being depressed and in this rotating position, the switch can be actuated by an outward motion of the knob that is transmitted to the switch via a transmitting unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This is a continuing application, under 35 U.S.C. § 120, of copending international application No. PCT/EP03/03282, filed Mar. 28, 2003, which designated the United States; this application also claims the priority, under 35 U.S.C. § 119, of German patent application No. 102 14 920.8, filed Apr. 4, 2002; the prior applications are herewith incorporated by reference in their entirety. 

   BACKGROUND OF THE INVENTION 
   Field of the Invention 
   The invention is based on a control unit, in particular for a stove top or burner unit, having at least one pop-out knob that can be used to operate at least one switch with a linear movement. 
   Operating units for a stove having a pop-out knob that is guided by a guide unit are known. The knob can be pushed-in in a neutral position and is prevented from being pushed-in in its remaining rotation positions by a blocking unit. Additional functions, such as activating a boost function or switching on a further zone, are implemented by turning the knob beyond a position associated with a maximum level. Turning the knob from the neutral position to the left, directly to the position associated with the maximum level, is precluded here due to the option of turning from the position associated with the maximum level to the right. 
   Published, Non-Prosecuted German Patent Application DE 197 22 044 A1 discloses an operating unit of this generic type for stoves which have a pop-out knob which can be used to operate a switch with a linear movement. The switch is operated when the knob is moved out of its pushed-in position and when the knob is moved to its pushed-in position. The switch controls an electrical circuit for a light fitting. 
   SUMMARY OF THE INVENTION 
   It is accordingly an object of the invention to provide an operating unit and a stove which overcome the above-mentioned disadvantages of the prior art devices of this general type, in which additional functions can be integrated in a pop-out knob in a flexible and physically simple manner. 
   With the foregoing and other objects in view there is provided, in accordance with the invention, a control unit. The control unit contains at least one switch, at least one pop-out knob for operating the at least one switch with a linear movement of the pop-out knob, a transmission unit, and a blocking unit. The knob is prevented from being pushed-in in at least one rotation position by the blocking, unit and, in a same rotation position, the switch can be operated by the linear movement of the knob, through the transmission unit. 
   The invention is based on the control unit, in particular for a stove, having at least one pop-out knob that can be used to operate at least one switch with a linear movement. 
   It is proposed to prevent the knob from being pushed-in in at least one rotation position by a blocking unit and in the same rotation position to allow the switch to be operated with the linear movement by the knob, via a transmission unit. The blocking unit can provide high operational reliability, and further functions can be integrated in the knob in a flexible and physically simple manner, and restriction to rotary movement of the knob, in particular restriction in terms of rotary movement from the neutral position directly to a position associated with a maximum level, can be easily avoided. Furthermore, the switch can advantageously be operated without the knob having to be returned to its rotation position associated with the pushed-in position, in particular its neutral position. 
   The switch may be formed by a variety of components which are considered to be useful by a person skilled in the art, for example by a light barrier which can be operated without contact or in particular by a linear movement switch, in which case the switch can be produced particularly cost-effectively and can also be used as a stop. 
   If a guide unit for the knob is disposed on a board, the switch may be disposed such that it is easily accessible with little complexity, specifically the switch may be disposed, in particular, directly on the board, as a result of which the use of additional wiring can be avoided. 
   Another refinement of the invention, proposes that the transmission unit be at least partially integral with the blocking unit. Advantageously, existing components can be used to operate the switch when the knob is not in a neutral position and savings can be made in terms of additional components, installation space, assembly effort and costs. 
   A physically simple and compact configuration can be achieved if the knob is configured so as to be rotatable with respect to a blocking element of the blocking unit, which blocking element is mounted such that it can move in the axial direction and on which an operating element for operating the switch is disposed, specifically in particular when the blocking element is in the form of a sleeve and has a base part which is in the form of an annular disk and can be used as a spring support for a spring which loads the blocking element and/or the knob. 
   The use of additional components can also be avoided by the operating element being integrally formed on the blocking element. 
   A further refinement of the invention proposes that the switch can be operated via the transmission unit in a rotation position in which the knob can be pushed-in. The knob can be assigned further functions, such as functions for controlling a display, a lighting unit etc., and savings can be made in terms of further operating elements and costs. In this case, two or more switches can be provided in total, or one switch may have different functions in different rotation positions of the knob. 
   If a switch for interrupting the electrical circuit is integrated in the operating unit, specifically in particular for an electrical circuit of a heating element, the use of an additional relay can be avoided, thus making it possible to save the costs associated with this. A live line and a neutral conductor of a heating element can be disconnected in a physically simple and cost-effective manner. In this case, for space reasons, the switch is advantageously in the form of a microcontact switch or of what is known as a 3 mm isolating switch. 
   Other features which are considered as characteristic for the invention are set forth in the appended claims. 
   Although the invention is illustrated and described herein as embodied in an operating unit and a stove, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
   The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagrammatic, front perspective view of a stove according to the invention; 
       FIG. 2  is a diagrammatic, sectional view taken along line II—II shown in  FIG. 1 , through a knob with its guide unit in a neutral position and in a pushed-in state; 
       FIG. 3  is a diagrammatic, sectional view of the knob from  FIG. 2  in an extended state; 
       FIG. 4  is a diagrammatic, sectional view of the knob in a rotation position other than a neutral position, with a linear movement switch operated; 
       FIG. 5  is a perspective, sectional view of the knob with its guide unit; and 
       FIG. 6  is a perspective view of the knob and its guide unit. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to the figures of the drawing in detail and first, particularly, to  FIG. 1  thereof, there is shown a stove having an oven with a cooking area  20 , which is bounded by a muffle  18  and an oven door  19 , and having a cook top or hob  21  integrated on the top of the oven. The oven and the cook top  21  can be controlled by a control unit that has six pop-out knobs  11  on the front of the stove. 
   The configuration and operation of a knob  11  associated with the cook top  21  are described in more detail in the text which follows, the knob  11  associated with the cooking area  20  being of corresponding configuration. 
   The knob  11  is guided by a guide unit  10  that is attached directly to a board  14  (FIG.  2 ). In addition to the guide unit  10 , further electronic components that are considered to be useful by a person skilled in the art, such as evaluation modules, display elements etc., can be mounted on the board  14 . The guide unit  10  has a first pot-shaped holder  22 , whose base part  33  is permanently welded to the board  14 . The holder  22  could also be attached to the board  14  by other connection methods considered to be suitable by a person skilled in the art, for example by riveting or clamping etc. A blocking element  15  of a blocking unit is guided on the holder  22  such that it can move in an axial direction, is in the form of a sleeve and has an annular base part  23  in the form of a disk. 
   An input unit having a bit generator  25  and a bit generator shaft  26 , on which a knob shaft  27  is mounted, is disposed in the holder  22 . Sliding contacts, magnetic input elements etc. could also be provided in place of the bit generator  25 . Furthermore, a helical compression spring  24  is disposed in the holder  22 , the first end of the helical compression spring  24  is supported on the base part  33  of the holder  22  and the second end of which helical compression spring  24  acts on the annular base part  23 , which is in the form of a disk, of the blocking element  15 . In the direction facing away from the bit generator  25 , the blocking element  15  is secured on the holder  22  by a bayonet setting that is not shown in any more detail. The knob  11  has an integrally formed projection  28  (which is in the form of a sleeve and points in the direction of the bit generator) for mounting on the knob shaft  27  such that they rotate together and can move in the axial direction. 
   In its pushed-in position, the knob  11  is loaded in the direction of its extended position by a helical compression spring  32 , whose first end is supported on the knob shaft  27 , and whose second end acts in the interior of the knob  11 . The knob  11  is held in its pushed-in position by a latching unit, which is not shown in any more detail. When the latching unit is released and the knob  11  is moved out of its pushed-in position by the helical compression spring  32 , a stop lug  29 , which is integrally formed at the end of the sleeve-like projection  28  and extends radially outwards, moves through a corresponding recess  30  in the annular base part  23 , which is in the form of a disk, of the blocking element  15  ( FIGS. 3 ,  5  and  6 ). The knob  11  can then be turned away from its neutral position or away from its rotation position associated with the pushed-in position either to the left, directly to a position associated with a maximum or high cooking level, or to the right to a position associated with a low cooking level, the knob  11  being turned relative to the blocking element  15 , which is mounted on the holder  22  such that they rotate together, and the bit generator shaft  26  in the bit generator  25  being turned with the knob  11  via the knob shaft  27 . When the knob  11  is not in the neutral position, it is prevented from being pushed-in by the stop lug  29  and the blocking element  15  of the blocking unit. 
   The stop lug  29  and the blocking element  15  form a transmission unit  12 , by which a short-travel switch  13  fitted in a recess in the board  14  can be operated by a linear movement of the knob  11  when it is not in the neutral position. If the knob  11  is pressed inward when it is not in its neutral position, the stop lug  29  on the knob  11  acts on the base part  23 , which is in the form of an annular disk, of the blocking element  15 , thus causing the blocking element to be moved in the axial direction toward the board  14 , against the spring force of the helical compression spring  24  (FIG.  4 ). In the process, an operating element  16 , which is in the form of a plunger, is integrally formed on the outer circumference of the blocking element  15  and extends in the axial direction toward the board  14 , comes into contact with the short-travel switch  13  and operates the latter. A boost function can be activated by the short-travel switch  13  when the knob  11  is not in the neutral position. It is also possible for further functions which are considered to be useful by a person skilled in the art to be controlled by the short-travel switch  13 , for example, switching on a cooking zone, turning an oven light on and off or turning display illumination on and off etc. The linear movement of the knob  11  in order to operate the short-travel switch  13  advantageously covers approximately 2 to 5 mm. 
   If the knob  11  is rotated from a position associated with a cooking level to its neutral position, contacts of a microswitch  17  which are disposed on the stop lug  29  and on the annular base part  23 , which is in the form of a disk, are disconnected and the power supply to a heating element associated with the knob  11  is interrupted. In the neutral position, the stop lug  29  on the knob  11  can be passed through the recess  30  in the annular base part  23 , which is in the form of a disk, and moved to its pushed-in position. Operation of the short-travel switch  13  by the stop lug  29  is precluded, but operation of the short-travel switch  13  by a second contact face  31  on the knob  11  is possible. 
   Shortly before the knob  11  reaches its pushed-in position, its contact face  31 , which adjoins the projection  28  in the direction of an operator, comes to bear against the base part  23 , which is in the form of an annular disk, of the blocking element  15 . If the knob  11  is moved further in the direction of its pushed-in position, the contact face  31  on the knob  11  acts on the base part  23 , which is in the form of an annular disk, of the blocking element  15 , thus causing the blocking element  15  to be moved in the axial direction with respect to the board  14  against the spring force of the helical compression spring  24 . In the process, the operating element  16 , which is in the form of a plunger, is integrally formed on the outer circumference of the blocking element  15  and extends in the axial direction with respect to the board  14 , comes into contact with the short-travel switch  13  and operates the latter. In the neutral position, as detected by the input unit, a controller that is not shown in any more detail allocates to the short-travel switch  13  a function which differs from the rest of the rotation positions. When the knob  11  is pushed-in, the short-travel switch  13  deactivates the display lighting, and when the knob  11  is extended, the short-travel switch  13  activates the display lighting.