Abstract:
The pressure cooker has a pot ( 2 ) with a base and a side wall and an upper rim ( 6 ). A lid ( 3 ) can be connected to the pot ( 2 ) in a sealed manner along the abovementioned upper rim ( 6 ). In the presence of a predetermined positive pressure, a locking device ( 12 ) connects the lid ( 3 ) to the pot in a non-releasable manner in conjunction with a pressure element ( 11 ) arranged on the lid ( 3 ). The locking device ( 12 ), in a fitting ( 5 ) of the lid ( 3 ), has a rocker ( 12   a ) which is mounted in a movable manner and, for control purposes and in order to lock the lid ( 3 ), interacts with the pot ( 2 ) and the abovementioned pressure element ( 11 ). Locking takes place automatically when the pressure cooker is closed and the locking means can be produced in a reliable and cost-effective manner.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a pressure cooker which has a pot with a base and a side wall and an upper rim, having a lid which can be connected to the pot in a sealed manner along the abovementioned upper rim, and having a locking device which, in the presence of a predetermined positive pressure, connects the lid to the pot in a non-releasable manner in conjunction with a pressure element arranged on the lid. 
   2. Background Art 
   Pressure cookers of this type have been known for a long time now. The pressure in the interior of the pressure cooker can be increased by the base of the pot being heated, so that the cooking process is accelerated. The lid is usually connected to the pot by means of the bayonet connection. The lid can be released from the pot by being pivoted. The locking device prevents the situation where the lid can be rotated, and thus released from the pot, in the presence of a significant positive pressure. The prior art has disclosed numerous such locking devices. These have, on the lid, a pressure element which, for example in the presence of a positive pressure, has a projecting stub or pin which interacts with a displaceable catch for locking purposes. 
   A pressure cooker of the type mentioned is disclosed, for example, in EP 0 123 197 A. This pressure cooker has, in a lid handle, a locking closure designed as a snap-fitting closure. The locking closure is intended to prevent the lid from being rotated unintentionally in relation to the pot. The lid handle here is connected to the lid in a releasable manner. 
   DE 27 05 712 A discloses a lid-locking and pressure-relief means on a steam pressure cooker. Locking takes place by way of a protuberance which, for unlocking purposes, can be displaced by way of an actuating knob which projects on the top side of a lid handle. During unlocking, a valve is opened at the same time and pressure is thus dissipated. 
   DE 203 18 647 U relates to a (steam) pressure cooker. The latter has two locking means, which means that production involves comparatively high outlay. 
   SUMMARY OF THE INVENTION 
   The object of the invention is to provide a pressure cooker of the abovementioned type which is distinguished by a more straightforward and cost-effective locking means. Nevertheless, it is intended for the locking means to be functionally reliable and straightforward to handle. 
   The object is achieved, in the case of a pressure cooker of the generic type, in that the locking device, in a fitting of the lid, has a rocker which is mounted in a movable manner and, for control purposes and in order to lock the lid, interacts with the pot and the abovementioned pressure element. Such a locking means may be designed with just a small number of parts and in a very space-saving manner. The rocker can be accommodated, for example, in a lid handle, it being possible for the lid handle to be of comparative narrow design. Locking takes place automatically, as does unlocking. Manipulation is thus neither possible nor necessary in order to release the locking means. 
   According to a development of the invention, it is provided that, when the lid is rotated, the rocker is controlled by a contour of the abovementioned rim. This has the significant advantage that there is no need for any additional parts in order to control the rocker. 
   According to a development of the invention, it is provided that the contour is formed by at least one bayonet. The costs are particularly low when, according to a development of the invention, for the purpose of locking the lid, the rim has a recess, stamped formation or a projecting part which interacts with the rocker. Such recesses and stamped formations can be mass-produced very cost-effectively. This is the case, in particular, when the recess or stamped formation, or the projecting part, is arranged on a bayonet. 
   According to a development of the invention, the rocker is mounted in an essentially concealed recess of the fitting. This is advantageous, in particular, from an aesthetic point of view. In addition, the rocker is thereby protected against being damaged. 
   Straight forward and secure mounting of the rocker is ensured when, according to a development of the invention, the rocker has a spindle by which it is mounted in the fitting such that it can be pivoted to a limited extent. 
   The locking means is particularly functionally reliable when, according to a development of the invention, the rocker has an arm which, in the locked position, is stop-blocked in a movable part of the pressure element. The movable part is, for example, a stub or a pin which, in the presence of a positive pressure in the pressure cooker, projects on the top side of the lid. 
   According to a development of the invention, it is provided that the rocker has a finger which, for the purpose of controlling the rocker when the lid is rotated, follows along a contour of the pot. This allows a particularly straightforward construction of the locking device. This is the case in particular when, according to a development of the invention, in the locked position, the finger engages with a bayonet. The invention allows, in particular, a symmetrical arrangement, so that the lid can be connected to the pot, for example, in two or three different positions. For example, it is possible for two or three bayonets to be arranged symmetrically and provided for the locking means. A significant advantage of the invention is also seen in the fact that the pressure cooker is hardly any different from a conventional pressure cooker. In particular, the pot may be produced such that it is essentially hardly any different from a pot without any locking means. 
   Particularly cost-effective production is achieved when the rocker is produced in one piece. It is also possible, however, for the rocker to be produced from a number of parts which are connected to one another in an articulated manner. 
   According to a development of the invention, the rocker is designed such that, when the lid is not fully closed, it deforms a sealing ring mounted in the lid, so that it is not possible for any pressure to be built up in the pressure cooker. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Exemplary embodiments of the invention are explained in more detail hereinbelow with reference to the drawings, in which: 
       FIG. 1  shows a three-dimensional view of a pressure cooker according to the invention, the lid having been removed; 
       FIG. 2  shows a lateral view of the pressure cooker according to the invention; 
       FIG. 3  shows a further view of the pressure cooker according to the invention, in which case, for illustrative reasons, the lid has also been removed; 
       FIG. 4  shows a three-dimensional view of the rocker; 
       FIG. 5  shows a three-dimensional view of a bayonet; 
       FIG. 6  shows a plan view of a pot with a variant of bayonets; 
       FIG. 7  shows a view of a lid handle with a rocker mounted therein, the rocker being depicted by dashed lines; 
       FIG. 8  shows a plan view of the pressure cooker according to the invention, the lid being shown in the unlocked position; 
       FIG. 9  shows a section through a pressure element; 
       FIG. 10   a  shows the pressure element according to  FIG. 9 , but in the blocking position; 
       FIG. 10   b  shows the pressure element in the overloaded position, in which, in the presence of positive pressure in the pressure cooker, steam is let out; 
       FIG. 11  shows a schematic view of a variant of a pressure cooker, parts having been left out for illustrative reasons; 
       FIG. 12  shows a plan view of the pressure cooker according to  FIG. 11 ; 
       FIG. 13  shows a further view of the pressure cooker according to  FIG. 11 ; 
       FIG. 14  shows a further view of the pressure cooker according to  FIG. 11 , in which the pressure cooker has been locked; 
       FIG. 15  shows a section through a variant of the pressure element; and 
       FIG. 16  shows a section through the pressure element in the blocking position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The pressure cooker  1  which is shown in  FIGS. 2 and 8  has, in an in fact conventional manner, a pot  2  which has a base with a side wall  9  that is open at the top and also a lid  3 , by means of which the pot  2  can be closed in a sealed manner. The pot  2  is provided in a known manner with fittings, in particular with a pot handle  4 , which in this case is designed as an elongate handle and a spaced handle  28 . It is also possible, however, for the pot handle  4  to be designed in some other way, as is known per se. The lid  3  likewise has fittings, in particular a lid handle  5 , shown also in  FIG. 7 , which is likewise an elongate handle and which, when the pressure cooker  1  is closed, is located above the pot handle  4 . 
   The lid handle  5  is thus fixed to the lid  3  and, in particular, is screwed thereto. In order to close the pressure cooker  1 , the lid  3  is positioned on the pot  2  and rotated relative to the pot  2  until the lid handle  5  is located above the pot handle  4 . 
     FIG. 8  shows the lid  3  in the unlocked position, the lid handle  5  thus having been rotated in relation to the pot handle  4 . 
   The connection between the pot  2  and the lid  3  is a bayonet connection, a plurality of bayonets  7  and  8  being arranged on the pot  2  according to  FIGS. 1 and 3  and, correspondingly, bayonets likewise being arranged in a known manner on the lid  3 .  FIG. 8  shows the lid  3  in the position in which it can be removed from the pot  2 . The pressure cooker  1  is closed by the lid  3  being rotated in a clockwise direction until the lid handle  5  is located above the pot handle  4  to thereby lock the lid  3 . For opening purposes, the lid  3  is rotated through the same angle in the counterclockwise direction. 
   Arranged on the lid  3  is a pressure element  11  which has a movable pin  13  and, at the same time, is a safety element which lets off steam in the presence of a predetermined positive pressure, in the position which is shown in  FIG. 10   b . As seen in  FIGS. 9 ,  10   a  and  10   b , this pin  13  is mounted such that it can be displaced in a bore  31  of a guide element  10   b  and a recess  30 . The pressure element  11  has a sleeve-like and elastomeric housing  29  with a groove  34  in which engages a periphery of a bore of the lid  3 , so that the pressure element  11  is fixed securely on the lid  3 . The recess  30  is protected against soiling in relation to the interior of the pressure cooker  1  by means of a screen  33 . The screen  33  is flexible. If there is no positive pressure prevailing in the interior of the pressure cooker  1 , then the pin  13  is located in the position which is shown in  FIG. 9 . If there is an increase in the pressure in the interior of the pressure cooker  1 , then the pin  13  is raised and, finally, projects beyond the housing  29  by way of its front end, as is shown in  FIG. 10   a . If there is a further increase in the pressure in the interior of the pressure cooker  1 , then, ultimately, the pin  13  moves into the position which is shown in  FIG. 10   b , in which a collar  32  blocks further movement and pressure is dissipated. 
   The pressure element  11  thus forms, at the same time, a safety valve which prevents an inadmissible pressure from being established in the pressure cooker  1 . 
   The pressure element  11  interacts with a locking device  12 , as shown in  FIGS. 1 ,  3  and  4 . This locking device  12  and the pressure element  11  are intended to prevent the possibility of the lid  3  being opened in the event of a positive pressure prevailing in the interior of the pressure cooker  1 . It is thus intended to achieve the situation where the lid  3  cannot be rotated in the presence of a positive pressure. 
   Opening is also to be reliably prevented in the presence of a comparatively small positive pressure of, for example, from 0.04 or 0.05 bar. Blocking is to take place automatically, so that it is ensured that opening is ruled out when the pressure cooker  1  is closed and positive pressure prevails. 
   The locking device  12  has a rocker  12   a  which is preferably, but not necessarily, in one piece and produced from plastic. According to  FIG. 7 , the rocker  12   a  is mounted in a pivotable manner in a recess  26  of the lid handle  5 . For mounting purposes, the rocker  12   a , according to  FIG. 4 , has a spindle  14  with two journals  15 , which engage in corresponding openings O (one shown here) in the interior of the recess  26  of the lid handle  5 , to guide pivoting movement of the rocker  12   a  relative to the lid handle  5  around an axis A. Located in the recess  26 , at a distance from the spindle  14 , is a spring element  27 , in particular a helical spring, which is connected to the rocker  12   a  at a protuberance  18 . It is also possible for the spring element  27  to act on any other location of the rocker  12   a  and to be designed, for example, as a leaf spring. 
   The protuberance  18  is located on an arm  16  which projects radially from the spindle  14  and, at a distance from the protuberance  18 , has a recess  17  which, in the locked position according to  FIG. 1 , interacts with the pin  13 . The arm  16  is fixed to the spindle  14  via a crosspiece  20 . The rocker  12   a  may be produced from plastic or a suitable metal. 
   Extending parallel to the arm  16  is a wall  21 , on which a finger  22  is integrally formed. This finger  22  interacts with a rim  6  of the pot  2  and, in particular, with a bayonet  7 . Spaced apart from the finger  22  is a protuberance  19  which, as can be seen, is somewhat thicker than the wall  21 . The wall  21  is mounted such that it can be pivoted around the axis A to a limited extent by way of the protuberance  19  in the recess  26 . The protuberance  19  serves for controlling the rocker  12   a  and is positioned such that it slides along the rim  6  when the lid  3  is rotated. As long as the lid  3  is not completely closed, the protuberance  19  acts on a conventional sealing ring  3   a  mounted in the lid  3 , and deforms the latter, so that it is not possible for any pressure to be built up in the pressure cooker. This ensures a further safety function. 
   In respect of the bayonet  7  which is shown in  FIG. 3 , the protuberance  19  is arranged such that, in the case of the lid  3  being positioned according to  FIG. 8 , the protuberance is located in front of a bayonet  7 , as is shown in  FIG. 3 . If the lid  3  is rotated in the clockwise direction from the position which is shown in  FIG. 8 , then the protuberance  19  moves onto the bayonet  7  and slides along the same. The protuberance  19  is deflected in the radial direction by the bayonet  7  and, correspondingly, the rocker  12   a  is rotated about the axis A of the spindle  14 . The finger  22  is pivoted, at the same time, by this rotary movement, to be precise such that it is moved radially inward. The protuberance  19  thus moves outward and the finger  22  moves inward. If the lid  3  is in the closed position, then the protuberance  19  butts against the outside of the bayonet  7  and the finger  22 , according to  FIG. 1 , engages in the region of the bayonet  7 . If there is no positive pressure in the pressure cooker  1 , then it is possible for the lid  3  to be rotated once again into the position which is shown in  FIG. 8 , and for the pressure cooker  1  to be opened. The rocker  12   a  here moves correspondingly in the opposite direction about the spindle  14 . This movement is assisted by the biased spring  27 . If a positive pressure then prevails in the interior of the pressure cooker  1 , this movement in the opposite direction is no longer possible. In the presence of positive pressure, the pin  13 , according to  FIG. 1 , projects on the top side of the lid, to be precise such that it is located directly in front of the recess  17 , as is shown in  FIG. 1 . It is thus no longer possible for the rocker  12   a  to be pivoted since the arm  16  is positioned against the projecting pin  13  by way of the recess  17 . 
   As has been mentioned above, in the above-cited position according to  FIG. 1 , the finger  22  engages in the region of the bayonet  7 . According to  FIG. 1 , the bayonet  7  is provided with a stamped formation  7   a  which deforms the bayonet  7  such that the latter is elevated in the region of the stamped formation. This stamped formation  7   a  forms a stop for the finger  22  and prevents the situation where the lid  3  can be opened. 
   Instead of the stamped formation  7   a , it is also possible, for example according to  FIG. 5 , for an upwardly projecting pin  23  or protuberance or the like to be arranged on a bayonet  7 ′ on a rim  6 ′ on a pot  2 ′. If an attempt is made to open the lid  3 , then the finger  22  positions itself correspondingly against the pin  23 . As an alternative, according to  FIG. 6 , it is also possible for a pot  2 ″ to have a bayonet  7 ″ with a recess  24  at a rim  6 ″. In the locked position, the finger  22  then engages in this recess  24  and it is thus no longer possible for the lid  3  to be opened. As  FIG. 6  shows, preferably at least two bayonets  7 ″ located opposite one another are provided with such a recess  24 . The lid  3  can correspondingly be placed on the pot  2 ″ in two positions. More than two symmetrically arranged bayonets  7 ″ are also possible in principle. The lid  3  can then optionally be placed, for example, in three positions. Locking takes place in all three positions, as has been explained above. This also applies, of course, to the bayonets  7  and  7 ′. 
   If, once cooking has been completed, the pressure cooker  1  has cooled and the positive pressure has largely dissipated, for example to below 0.04 or 0.05 bar, then the pin  13  is once again located in the position which is shown in  FIG. 9 . The lid  3  can then readily be rotated into the position which is shown in  FIG. 8 . The rocker  12   a  can be pivoted here since the pin  13  no longer prevents the rocker  12   a  from being pivoted about the spindle  14 . The pivoting movement of the rocker  12   a  causes the finger  22  to be moved radially outward, and it thus disengages from the stamped formation  7   a , or the pin  23 , or moves out of the recess  24 . Since there is no positive pressure present in the interior of the pressure cooker  1 , this movement, or the opening of the pressure cooker  1 , is safe. 
     FIGS. 11 to 16  show a locking device  35  which is likewise mounted in a corresponding recess of the pot handle  4 . The locking device  35  has a spindle  47  by means of which it is mounted in a pivotable manner in the recess. The spindle  47  is connected, for example according to  FIG. 12 , to a finger  49  and to an arm  48  such that it can be pivoted via a lever  46 . The lever  46  engages with a pin  44  which, according to  FIG. 12 , butts against the rim  6 ″ by way of a front end on account of the biasing of a spring element  45 . The pin  44  is connected in a pivotable manner to the lever  46 . The finger  49  corresponds, in terms of functioning, to the finger  22  and the lever  48  corresponds, in terms of functioning, to the arm  16 . The pin  44  is mounted in a displaceable manner in the pot handle  4 , the spring  45  being supported on the pot handle  4 . 
   The locking device  35  interacts with a pressure element  11 ′ which is designed according to  FIGS. 15 and 16  and, unlike the pressure element  11 , does not perform any safety function. As can be seen from these figures, the pressure element  11 ′ has a sleeve-like body  39  which is mounted in captive and displaceable fashion in an opening  38  of the lid  3 ′. A sealing ring  42  is arranged between the inside  43  of the lid  3 ′ and a collar  41 . A thickened portion  40  is spaced apart from the collar  41  and fixes the pressure element  11 ′ in the lid  3 . In the presence of a positive pressure in the pressure cooker, the pressure element  11 ′ moves into the position which is shown in  FIG. 16  and in which, as can be seen, the pressure element  11 ′ projects on the top side of the lid  3 . It is also possible, however, for the pressure element  11 ′ provided in this embodiment to be replaced by the pressure element  11  which is shown in  FIGS. 9 and 10 . 
     FIGS. 11 and 12  show the locking device  35  in the unlocked state, in which the lid  3  can thus be rotated. The pressure element  11 ′ is located in the position which is shown in  FIG. 15 . 
     FIGS. 13 and 14  show the locking device  35  in the locked state. With the lid  3  located in the closed position and the pressure element  11 ′ located in the position which is shown in  FIG. 16 , the body  39  projects upward. The pin  44  is biased counter to the spring  45  and butts against a bayonet  36  on the pot  2 ″′. The bayonet  36  forces the pin  44  into a position in which it is arranged further outward in the radial direction than in the unlocked position, which is shown in  FIG. 12 . On account of the position of the lever  46 , the finger  49  is located further inward in the radial direction in the position which is shown in  FIG. 14 . If an attempt is then made to open the lid  3 , the arm  48  engages with the projecting pressure element  11 ′. The finger  49  thus cannot be rotated into the position which is shown in  FIG. 12 . It remains essentially in the position which is shown in  FIG. 14  and, ultimately, butts against a shoulder  37  of the bayonet  36 . It is thus not possible for the lid  3  to be rotated any further or, consequently, opened. 
   The bayonet  36  is, as can be seen, of shortened form here. It is also conceivable, however, to have an embodiment in which the finger  49  is positioned against a shoulder of a non-shortened bayonet. A hitherto conventional pot can thus be used with this embodiment. 
   LIST OF DESIGNATIONS 
   
       
         1  Pressure cooker 
         2  Pot 
         3  Lid 
         4  Pot handle 
         5  Lid handle 
         6  Rim 
         7  Bayonet 
         8  Bayonet 
         9  Wall 
         10  Outside 
         11  Pressure element 
         12  Locking device 
         12   a  Rocker 
         13  Pin 
         14  Spindle 
         15  Journal 
         16  Arm 
         17  Recess 
         18  Protuberance 
         19  Protuberance 
         20  Crosspiece 
         21  Wall 
         22  Finger 
         23  Pin 
         24  Recess 
         25  Stamped formation 
         26  Recess 
         27  Spring element 
         28  Handle 
         29  Housing 
         30  Recess 
         31  Bore 
         32  Collar 
         33  Screen 
         34  Groove 
         35  Locking device 
         36  Bayonet 
         37  Shoulder 
         38  Opening 
         39  Body 
         40  Thickened portion 
         41  Collar 
         42  Sealing ring 
         43  Inside 
         44  Pin 
         45  Spring element 
         46  Lever 
         47  Spindle 
         48  Arm 
         49  Finger