Abstract:
The invention relates to a closing device for a container with an opening, in particular for a cooking pot with an outwardly protruding pouring edge, said closing device comprising a lid for closing the opening of the container, a closing element arrangement with at least a first closing element, and a movement device for moving the first closing element, said first closing element being able to be moved in an inward direction upon actuation of the movement device and moving upward at least in parts during the inwardly directed movement.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a closing device for a container in general and for a cooking pot or steam pressure cooking pot in particular. 
   2. Description of Related Art 
   At a time of increasing health awareness, there is also a greater demand for food preparation methods which are advantageous from the point of view of nutrition. At the same time, in a hectic world in which people want to and are able to spend less and less time on everyday household chores, there is a desire for fast and efficient food preparation. Steam pressure cooking pots satisfy these two apparently conflicting requirements outstandingly by permitting rapid and gentle cooking of food. 
   In principle, steam pressure cooking pots have been known for decades. However, the known steam pressure cooking pots have a number of disadvantages. 
   From the fifties, for example, and more specifically from patent specification DE 896 409, a steam pressure cooking pot is known with a lid which is closed by means of three jaws gripping round the edge of the lid. A disadvantage of this closure mechanism is that a substantial force is needed for closing it, this force being applied via an unwieldy lever. 
   More recent developments in the field of steam pressure cooking pots are described in laid-open specifications WO 96/01070, EP-A-1 029 483 and EP-A-1 082 932, for example. 
   A closure device which is known from laid-open specification WO 96/01070 has a lid with two radially displaceable clamping jaws which are drawn together by a spring mechanism. A disadvantage here is that a seal is prestressed in an undefined manner by pressing vertically on the lid before the clamping jaws are closed. The clamping jaws then slide abruptly inward and cause an annoying noise when they strike the pot edge. 
   Laid-open specification EP-A-1 082 932 discloses a steam pressure cooking pot with a similar lid as in document WO 96/01070. 
   U.S. Pat. No. 5,613,424 discloses a control device for opening and closing closure jaws for a pressure pot. The device comprises a control element which is mounted on a lid and, engaging in movement arms, moves radially with respect to the lid. 
   Furthermore, patent specification CH 254 203 describes a steam pressure cooking pot with an outwardly protruding edge. The lid of the steam pressure cooking pot comprises three gripping members which are bent in a U shape at their ends and which engage under the edge and press the lid with an interposed seal against the top face of the pot edge. 
   The document FR 2 809 608 A1 discloses a closing and opening device for a lid of a steam pressure cooking pot, which lid has four arms with clamping jaws which are driven by rotation of a control element. 
   In addition, laid-open specification EP-A-1 029 483 discloses a lid for a pressure pot with four movable clamping jaws which can be moved radially via a crank mechanism. This crank mechanism comprises a large number of movable components, some of them made of plastic. This crank mechanism is therefore complicated and expensive to produce and assemble, is not long-lasting, and is problematic with regard to hygiene requirements. 
   All of said devices have, however, further serious disadvantages in common. 
   The devices mentioned are cumbersome, esthetically unappealing, difficult to clean, and have to be produced with small tolerances. 
   SUMMARY OF THE INVENTION 
   In addition, a further serious disadvantage is that the known devices can be used only on specially adapted for moving at least the first closing element, preferably all of the closing elements. 
   The container has an axis which extends from a base to the opening and which in the case of circular containers in particular constitutes the axis of symmetry of rotation of the container. The axis preferably extends perpendicular to the container base. 
   The container moreover has an opening plane which is defined by the pouring edge and which preferably extends parallel to the container base and perpendicular to the axis. The first closing element or the closing elements is/are directed inward or moved toward the axis by an actuation of the movement device, and, during the inwardly directed movement or displacement, there occurs an upward movement, or movement away from the container base, of at least a portion of the closing element or closing elements. 
   This movement or displacement, in particular directed obliquely inward and upward, of the closing element or closing elements advantageously ensures a controlled downwardly directed pressure of the closing device onto the container or cooking pot, in particular for the defined prestressing of a seal arranged between the lid and the container. 
   Moreover, a reliable closure is ensured by the upward movement of the closing element or of the closing elements even in the case of considerable production tolerances. The closing device according to the invention is also especially suitable for commercially available cooking pots with an outwardly protruding pouring edge which is angled obliquely downward in the outer area. For cooking pots like these, most of the known lids for steam pressure cooking pots are not suitable, because their clamping jaws in most cases move horizontally, i.e. parallel to the opening plane or perpendicular to the axis. If known closing devices of this kind were nevertheless to be used in an inappropriate way, they would engage on the outermost, downwardly projecting portion of the pouring edge, i.e. with substantial leverage, and would possibly bend the pouring edge out of shape. 
   By contrast, the closing element of the closing device according to the invention is able to engage farther inward in relation to the pot axis. For this reason, the closing device according to the invention can cooperate with commercially available cooking pots, including those with relatively thin walls, resulting in a steam pressure cooking pot arrangement that is able to withstand pressure. 
   In particular, the closing element arrangement defines at least an open position in which the closing device can be removed from the container, and a closure position in which the lid seals the container, in particular in a substantially liquid-tight manner. 
   The container sealed off in the closure position is preferably able to withstand pressures up to at least about 5 bar internal pressure or internal overpressure. 
   In the open position, the closing element or closing elements is/are preferably in a first, in particular outer position, and, in the closure position, the closing element or closing elements is/are preferably in a second, in particular inner position, and it/they can be moved or displaced between the first position and second position. The movement or displacement between the first position and second position takes the form in particular of an inwardly directed radial movement in which the first closing element or the closing elements slides/slide on the lid. 
   The first closing element has in particular an outer edge for engaging on the pouring edge of the container. Upon the obliquely upward and radially inward movement of the first closing element, the outer edge comes to bear from underneath on the pouring edge of the container and, through the upward component of the movement, impacts the pouring edge with an axially upwardly directed force component. 
   The outwardly protruding pouring edge particularly preferably has an outwardly extending, substantially horizontal inner ring portion and a downwardly or obliquely downwardly extending outer ring portion. By means of the obliquely inward and upward movement of the first closing element upon closure of the container, the outer edge of the closing element can bear, at least in parts, from below on the inner ring portion of the pouring edge. The bearing point or ring is preferably situated as far inward as possible, e.g. on the inner half of the inner ring portion, so that the lever conditions are optimized and only a slight torque is exerted on the pouring edge. In particular, the bearing point or ring is not situated on the outer ring portion of the pouring edge. 
   According to a preferred embodiment of the invention, the outer edge of the closing element comprises a downwardly extending first portion and an upwardly extending second portion, the second portion being arranged to the inside of the first portion with respect to the container axis. The second portion ascends, for example perpendicularly or obliquely inward in relation to the opening plane. 
   Between the first portion and second portion there is preferably a third portion, which preferably extends substantially parallel to the plane of the pot. Upon closure of the closing device, the second portion in particular of the outer edge of the closing element comes to bear with force on the inner ring portion of the container, so that the closing device and with it possibly also the seal are pressed onto the container. In this case, the closure position is particularly preferably held with self-locking through the frictional forces generated. 
   It has proven particularly advantageous, and it is therefore preferred, to have an angle in the range of 5° to 30°, in particular in the range of 10° to 20°, most preferably in the range of about 15°, between the obliquely upwardly directed movement of the outer edge of the closing element, upon closure, and the opening plane of the container. 
   The seal is in particular designed as a sealing ring and preferably extends in a circle about the closing device. The seal is preferably attached to the lid in a releasable manner and is made for example of silicone or silicone-containing material. 
   It is particularly expedient to use what is called a sealing lip or lip seal, which has a substantially U-shaped or V-shaped cross section. The lip seal has the particular advantage that the pressure generated in the inside of the container forces the seal apart and thus improves the sealing action. Thus, relatively slight prestressing, as is generated by the closing operation, is still sufficient to achieve a closure that is very resistant to pressure. 
   According to a preferred development of the invention, the closing element has substantially the shape of a segment of a circle. 
   In particular, however, the segment tip can be removed or cut out. The circle segment shape is advantageous particularly in connection with an arrangement consisting of a plurality of preferably identical closing elements. 
   In the closure position, the closing elements particularly preferably form a substantially closed covering, by virtue of the fact that the circle-segment-shaped closing elements laterally adjoin one another, preferably flush with one another. There are preferably 2, 3, 4, 5, 6, 8 or more closing elements used. An optionally remaining central opening in the arrangement of closing elements is preferably covered from sight by a handle which is part of the movement device, so that in the closure position the impression given is of a conventional pot lid. In particular, in the closure position the lid is covered or concealed more or less completely by the closing element arrangement. 
   The lid and/or the closing element arrangement are preferably bulged outward at least in parts and preferably each form a sphere portion. In this embodiment, the closing elements preferably lie flat on the lid and slide on the latter. A radius in the range of 100 mm to 1000 mm, preferably in the range of 300 mm to 600 mm, has proven particularly expedient for the curvature of the sphere portions. 
   The closing element arrangement and the lid can preferably be connected to one another in a releasable manner by a central securing means, for example a screw. This makes it much easier to thoroughly clean the closing device. 
   The closing device, in particular the lid, preferably has centering means, for example projections extending downward from the lid. In the open position and/or the closure position, the centering means ensure a reliable and precise centering of the closing device, in particular of the lid, on the container. 
   The movement device preferably comprises a slotted guide disk secured on the handle, for example. In addition to having an axial bore, the slotted guide disk has, for each closing element, a curved slot extending obliquely to the circumference of the slotted guide disk. In the slot there is a bolt which is connected in fixed position to the corresponding closing element. By turning the slotted guide disk, the bolt is thus radially displaced with the closing element. Alternatively or as a complement to this, a toothed gear arrangement can also be used. 
   It is particularly preferable for the closing device, excluding the handle, to be made, in particular completely, of metal, for example of stainless steel. This gives a sturdy, long-lasting and hygienic closing device in which the coefficients of expansion of different component parts are adapted to one another and to the container. 
   Moreover, the closing device according to the invention preferably comprises a safety means with a blocking means for blocking the movement of the closing elements and/or an overpressure relief valve, in order to meet the legal safety requirements. Such safety means are known in principle to the person skilled in the art. 
   The invention is explained in more detail below on the basis of preferred embodiments and with reference to the figures. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
       FIG. 1  shows a partially sectioned top view of a first embodiment of the closing device according to the invention, in a closure position, 
       FIG. 2  shows a side view of the closing device from  FIG. 1 , 
       FIG. 3A  shows a sectional view along the line A—A of a firtst embodiment of a detail of the closing device from  FIG. 1 , together with a detail of a pot, 
       FIG. 3B  shows a sectional view along the line A—A of a second embodiment of a detail of the closing device from  FIG. 1 , together with a detail of a pot, 
       FIG. 4  shows an enlarged detail of the closing device and of the pot from  FIG. 3 , but in an open position, 
       FIG. 5  shows a detail of a sectional view of a second embodiment of the closing device according to the invention, corresponding to a section along the line B—B in  FIG. 1 , 
       FIG. 6   a  shows a detail of a sectional view of a third embodiment of the closing device according to the invention, corresponding to a section along the line A—A in  FIG. 1 , in the open position, 
       FIG. 6   b  shows the same view as  FIG. 6   a , but in a half closed position, 
       FIG. 6   c  shows the same view as in  FIG. 6   a , but in the closure position 
       FIG. 7  shows a detail of a sectional view of a closing element according to a fourth embodiment of the invention, 
       FIG. 8  shows a sectional top view of the closing device without handle, and 
       FIG. 9  shows a sectional view through a safety means. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows an embodiment of the closing device  1  according to the invention with a closing element arrangement  2 , comprising four closing elements  10 ,  20 ,  30 ,  40  which are substantially in the shape of segments of a circle, and a rotationally symmetrical and rotatable handle  50  which is arranged centrally with respect to the closing device  1 . Each of the four closing elements  10 ,  20 ,  30 ,  40  has in each case a central arc-shaped cutout  12 ,  22 ,  32 ,  42  and in each case two mutually adjoining cutouts  14   d ,  14   a ,  24   a ,  24   b ,  34   b ,  34   c ,  44   c ,  44   d  which are arranged at the outer corners of the closing elements located on the circumference. 
   In the closure position of the closing device  1  shown in  FIG. 1 , the cutouts  12 ,  22 ,  32 ,  42  substantially form a central circular cutout  4  of the closing element arrangement  2 . The cutouts  14   d ,  14   a ,  24   a ,  24   b ,  34   b ,  34   c ,  44   c ,  44   d  form four cutouts  6   a ,  6   b ,  6   c ,  6   d  arranged at 90° along the circumference of the closing element arrangement  2 . 
   The four closing elements  10 ,  20 ,  30 ,  40  each have two radial edges  16   d ,  16   a ,  26   a ,  26   b ,  36   b ,  36   c ,  46   c ,  46   d  and in each case an outer arc-shaped edge area  18 ,  28 ,  38 ,  48 . 
   The closing element arrangement  2  is preferably first produced in one piece and shaped and then cut by means of a laser or a saw into four equal closing elements  10 ,  20 ,  30 ,  40 . The laser cutting is particularly advantageous, as this avoids deburring. 
   The closing device  1  has been cut open in the area S so that a cutout of a slotted guide disk  60  and of a retaining and guide plate  70  can be seen. 
   The diameter of the closing device is about 240 mm, and the thickness of the closing elements is about 1 mm to 1.2 mm. 
     FIG. 2  shows the closing device  1  in a side view along the direction C in  FIG. 1 . This view includes the two closing elements  20  and  30 , the handle  50 , and a lid  80  which is arranged inside the closing element arrangement  2 . The lid  80  has four centering tabs  82   a ,  82   b ,  82   c ,  82   d  which are arranged in the cutouts  6   a ,  6   b ,  6   c ,  6   d  of the closing element arrangement  2 , and of which the rear centering tab  82   d  is not shown. 
     FIG. 3A  shows the closing device  1  in the closure position (solid lines). An edge area  140  of the closing element  40  is also indicated in the open position by broken lines. The other closing elements  10 ,  20 ,  30  are essentially identical to the first closing element  40 . 
     FIG. 3A  also shows a movement device  90  comprising the handle  50  made of plastic, the metal slotted guide disk  60 , the metal guide plate  70 , a screw  92 , a drive pin  94 , a guide screw  96 , a central screw  98 , and a central nut  99 . 
   The handle  50  comprises a rotation knob  52  and a finger protection plate  54 . The guide plate  70  is arranged between the slotted guide disk  60  and the closing element  40  and is completely concealed by the handle  50 . 
   The guide screw  96  connects the closing element  40  to the guide plate  70 , the closing element  40  being radially displaceable with respect to the guide plate  70 . Upon the displacement, the guide screw  96  slides in a radially extending oblong hole  71  in the closing element  40 . The drive pin  94  connects the closing element  40  to the guide plate  70 , likewise in a radially displaceable manner, with the drive pin  94  sliding in an oblong hole  72  of the guide plate  70 . The is drive pin  94  further extends through a curved oblong hole  64  in the slotted guide disk  60 . The mechanism of displacement for the other three identical closing elements  10 ,  20 ,  30  is of equivalent design. 
   By turning the handle  50  about an axis  122  and the slotted guide disk  60  secured on the handle  50 , the closing element  40  is displaced radially between the open position and the closure position by means of the drive pin  94 . 
     Fig. 3B  shows a movement device  90  comprising the handle  50  made of plastic, the metal slotted guide disk  60 , the metal guide plate  70 , a screw  92 , a drive pin  94  having a toothed gearing  94   a , a guide screw  96 , a central screw  98 , and a central nut  99 . 
   The guide screw  96  connects the closing element  40  to the guide plate  70 , the closing element  40  being radially displaceable with respect to the guide plate  70 . Upon the displacement, the guide screw  96  slides in a radially extending oblong hole  71  in the closing element  40 . The toothed gearing  94   a  of drive pin  94  connects the closing element  40  to the guide plate  70 , likewise in a radially displaceable manner, with the drive pin  94  sliding in an oblong hole  72  of the guide plate  70 . The toothed gearing  94   a  of drive pin  94  engages a curved oblong toothed gearing  64   a  of the slotted guide disk  60 . The mechanism of displacement for the other three identical closing elements  10 ,  20 ,  30  is of equivalent design. 
   By turning the handle  50  about an axis  122  and the slotted guide disk  60  secured on the handle  50 , the closing element  40  is displaced radially between the open position and the closure position by means of the toothed gearing  64   a ,  94   a.    
   The closing element arrangement  2  and the lid  80  can be easily separated from one another by removing the central nut  99 , for example for cleaning purposes. 
   An enlargement of the edge area  140  is illustrated in  FIG. 4  in the open position.  FIG. 4  shows a circularly extending lip seal  110 . The lip seal  110  is made of silicone and is of substantially U-shaped cross section. The lip seal  110  comprises a central portion  112  and an upper lip portion  114  and lower lip portion  116 . The central portion  112  and the upper lip portion  114  lie from inside and from below against the lid  80 . The lower lip portion  116  comes to bear on a pouring edge  130  of a pot  120  of circular cross section, when the closing device  2  is fitted onto the pot or cooking pot  120 . 
   The closing element  40  has a lid portion  49  which curves outward in relation to the inside of the pot, and a claw-like edge portion  140  for engaging around the pouring edge  130 . The surface of the lid portion  49  is in the shape of a spherical portion with a radius of about 400 mm. The claw-like edge portion  140  has a first downwardly extending portion  142  and a second upwardly extending portion  144 . Here, the terms downward and upward are to be understood extending in the path of the closing element  40  away from the center or the axis  122 . Arranged between the first portion  142  and the second portion  144 , there is a third portion  146 , which according to this illustrative embodiment is horizontal. The second and third portions  144 ,  146  are arranged inward in the direction of the axis or pot axis  122  in relation to the first portion  142 , and under the lid portion  49 . The closing element  40  is made of metal, in particular of stainless steel sheet, and the edge portion  140  is bent, rolled or beaded, so that curved portions  141 ,  143  and  145  are obtained between the portions  49 ,  142 ,  146  and  144  of the closing element  40 . 
   The pouring edge  130  of the pot  120  has an inner ring portion  132  extending horizontally, or parallel to the pot surface  121 , and a downwardly beveled outer ring portion  134 . 
   In this embodiment, the centering tabs  82   a ,  82   b ,  82   c ,  82   d  are produced in one piece with the lid  80  and are indicated by broken lines in  FIG. 4 . 
     FIG. 5  shows a detail of a sectional view corresponding to a section along the line B—B in  FIG. 1 . 
     FIG. 5  illustrates an alternative embodiment of the centering tabs. A centering tab  82   c  is shown which has been secured, for example welded, from the outside onto the outer edge of the lid  80 . 
     FIGS. 6   a  through  6   c  show the movement of a closing element  40 ′ which has been modified compared to the closing element  40 . The closing element  40 ′ comprises an outer, downwardly extending first portion  142 ′, and an obliquely upwardly extending second portion  144 ′. Adjoining the second portion  144 ′ there is a substantially horizontally extending end portion  148 ′. Curved portions  141 ′ and  143 ′ are also present. 
     FIG. 6   a  shows the closing element  40 ′ in the open position. During closure, the closing element  40 ′ slides on the lid  80  in direction D. 
   It is obvious that the second portion  144 ′ and the end portion  148 ′, together with the whole closing element  40 ′, move upward during the inward closing displacement. As can best be seen from  FIG. 3 , the angle α between the direction of movement of the end portion  148 ′ is about 18° in these illustrative embodiments. 
     FIG. 6   b  shows the closing element  40 ′ or closing device  1  in a half closed position, in which the inner portion  144 ′ already overlaps the pouring edge  130  of the pot  120  in part. 
   Referring now to  FIG. 6   c , the closing element  40 ′ or closing element arrangement  2  is shown in the closed state or closure state. In the closure state, the second portion  144 ′ of the closing element  40 ′, or more exactly the inner horizontal end portion  148 ′, bears with force on the pouring edge  130 . It is obvious that, by means of the oblique upward movement of the closing element  40 ′, a perpendicular or axial force is exerted on the lid  80  and lip seal  110 , so that a defined prestressing of the lip seal  110  is obtained. In particular, the seal  110  is automatically prestressed when the movement device  90  is actuated to effect closure. 
   The point of engagement of the horizontal inner portion  148 ′ lies relatively far inward on the pouring edge  130 , in this illustrative embodiment within the center of the inner ring portion  132 . In this way, the torque on the pouring edge  130  is kept low, with the result that the closing device  1  can even be used for pots  120  with a pouring edge thickness of less than 1.2 mm or less than 1.0 mm. 
     FIG. 7  shows a fourth embodiment for the form of the outer edge of the closing element. According to this fourth embodiment, the outer edge  140 ″ comprises an obliquely upwardly and inwardly extending second portion  144 ″ with an end portion  148 ″ which is bent downward in an arc shape and comes to bear on the pouring edge in the closure position. 
     FIG. 8  shows a plan view looking at the center of the closing device without the handle  50 . This view shows the slotted guide disk  60  of stainless steel with four curved oblong holes  61 ,  62 ,  63 ,  64  which do not extend parallel to the circumference of the slotted guide disk  60  and thus, upon rotation, radially displace the drive pins  94  and, with them, the four closing elements  10 ,  20 ,  30 ,  40 . 
     FIG. 9  shows a safety means  150  with a blocking device and integrated overpressure relief valve. The safety means  150  comprises a housing  151 , a screwed connection  152 , a valve pin  153 , a valve spring  154 , a valve ball  155 , and an O-ring  156 . 
   If the internal pressure in the closed pot rises above a first threshold value, the valve pin  153  is pushed upward through an opening in the closing element  40 , so that the closing element arrangement  2  is blocked and can no longer be opened. If the pressure rises above a second threshold value, e.g. 5 bar, pressure is released automatically via the valve ball  155 . 
   It will be clear to the skilled person that the invention is not limited to the embodiments described above and that instead it can be varied, particularly in relation to the concrete design of the outer edge of the closing elements and of the pouring edge, without departing from the spirit of the invention.