Abstract:
Disclosed is an electromechanical locking device for a door of an appliance, particularly an oven. Said locking device comprises a lock ( 1 ) on the appliance and a hook ( 2 ) on the door. The lock ( 1 ) is provided with bolts ( 3, 4 ) on both sides of the hook ( 2 ), said bolts ( 3, 4 ) allowing the door to be opened and closed in an intermediate latched stage and a main latched stage.

Description:
This application claims the benefit of German Application No. 10 2006 017 984.6 filed Apr. 13, 2006, German Application No. 10 2006 019 515.9 filed Apr. 27, 2006, and PCT/DE2007/000659 filed Apr. 13, 2007, which are hereby incorporated by reference in their entirety. 
     The invention concerns an electromechanical locking device for an appliance door, in particular an oven, with a lock on the appliance and a hook on the door. 
     There is a multitude of appliance doors in which the opening process is carried out in two stages. The hook is first released from the appliance lock from the main latched stage into an intermediate latched stage, so that a direct opening of the door does not occur. The background for this is represented, for example, in the case of toaster ovens, by the requirement that the heated air should first escape from the interior of the oven, so that the operating personnel will not inhale said air. A large gap is rather created between oven and door in the intermediate latched stage, so that the air can escape past the body of the operating personnel in lateral direction. Only then can the door be completely released through a second, separate manipulation. 
     It is an object of the invention to improve the locking functions and thus create a more reliable and easier to manage appliance door. 
     This object is attained by arranging bolts in the lock on both sides of the hook, which are designed so as to allow opening and closing the door in an intermediate latched stage and in a main latched stage. 
     Bolts, which interact together to make possible the functions of the main and intermediate latched stages, are arranged on both sides of the hook. The door is first moved manually into the intermediate latched stage, and is then pulled shut in the main latched stage via a drive motor by means of an interaction of the bolts. 
     This interaction is considerably facilitated if both bolts have mutually corresponding locking surfaces, so that when the door is opened and/or closed, the corresponding latched positions are produced. The locking surfaces of the bolts rest one against the other or slide over each other when the door is opened or closed. 
     For this purpose, it is proposed to configure a first bolt as a swivel-mounted rotary door latch. The rotary door latch has an arm beside a region designed to correspond to the hook, whose end is configured so as to correspond to the neighboring hook, as well as also another arm, via which the rotary door latch can be actuated by means of the drive motor. 
     In this regard, the rotary door latch can be provided with an elongated holder for receiving the hook. In this way a kind of recess with an end configured as a hub-like projection is obtained which is suitable, in turn, for creating a locking connection with the hook. The appliance door slips thus with the hook into the recess when the door is closed, and is then enclosed by the projection after a corresponding actuation of the rotary door latch in order to create a locking connection. The recess is configured therein in such a way that the hook is in the main latched stage in its end position. 
     In addition, a second bolt is positioned on the opposite side of the hook with respect to the rotary door latch. Each bolt influences the operation of the other bolt, without there being any possibility of a mutual interference. An increased number of functions can be obtained if the second bolt is configured in two parts. One part of the bolt has one end on the side of the hook and the second end is in direct or indirect contact with the drive motor. 
     The invention conceives in particular that the second bolt has a locking lever on the side of the hook and a locking pawl. The former has one end in the shape of a projection or catch, which has a configuration that corresponds to the hook and is suitable for making a connection with said hook in the intermediate latched stage when the door is closed. Between this locking lever and the drive motor the other part of the bolt, the locking pawl, is located, which keeps the locking lever out of the travel path of the hook or releases said locking lever for locking upon release of a corresponding contact. 
     This can be most, effectively implemented when the locking lever and the locking pawl are connected to each other by means of a mortise and tenon joint. In this regard, the invention conceives in particular that the locking lever has a tenon, while the locking pawl has a recess at the end thereof facing the tenon, so that the mortise and tenon joint is released when the locking pawl is moved corresponding to the other end thereof by the drive motor or is moved into another position by the rotary door latch. 
     Locking surfaces are provided between the rotary door latch and the locking pawl. It is best herein to configure the latch surfaces as recesses and/or projections, so that several positions of the locking surfaces with respect to each other are possible, which will determine the intermediate or main latched position of the lock. 
     The invention proposes in particular to provide the rotary door lock with two projections and the locking pawl with one projection. The projection of the locking pawl is arranged between the two projections of the rotary door latch when the door is in the intermediate latched position; when the door is closed to the main latched position, the upper projection of the rotary door latch also slides behind the projection of the locking pawl. 
     An additional embodiment of the invention proposes to equip both bolts with status sensors in order to be able to check the open state of the lock in a contactless or contacted manner, and if necessary control the opening and/or closing of the door. In this regard, both status sensors can function independently from each other. 
     It was already pointed out that the motor function is an essential component of the locking device according to the invention. In addition to an exclusively electrical opening, it is likewise possible to implement an exclusively manual opening function in this manner. In any case, it is recommended that the bolts be controllable directly or indirectly by means of separate drive motors. For this purpose, it is proposed to set a cam wheel in rotation by means of the respective drive motor, whereupon the cam wheel can be brought into contact with the bolts. 
     One embodiment proposes the use of rotatably mounted cams in order to transfer the torques exerted by the drive motors, which are mounted on the wheels. Both wheels are independently controlled by means of the drive motors with respect to the opening and the closing process. 
     With regard to the hook, the invention proposes providing the hook with a pin on its front side and a wedge at a distance therefrom on the inside of said hook. In this case, the pin is configured so as to correspond to the recess in the rotary door latch, and the wedge corresponds to the locking pawl. In this way, a good connection is ensured between the rotary door latch and the pin in the latched stages, on the one hand, and it is ensured, on the other, that a guide contour for the locking lever is created by means of the wedge to provide the latter with temporary additional support. 
     The invention is characterized in particular in that an electromechanical locking device is created for an appliance door, with which said door can be reliably and securely opened and closed. Differently configured and working bolts can be provided for this purpose on both sides of the door hook. The two bolts operate essentially independently from each other, so that they are driven by different drive motors, but also operate in a mutually dependent manner in such a way that they have mutually matching locking surfaces, which ensure the opening and/or closing of the door, respectively. 
     Additional details and advantages of the object of the invention are obtained from the following description of the corresponding figures, in which a preferred embodiment with the necessary details and individual parts is represented. In the drawings: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an illustration of the inner mechanism of the lock; 
         FIG. 2  shows a section thereof in perspective view; 
         FIG. 3  shows a lock in the intermediate latched position during closing; 
         FIG. 4  shows a lock in the main latched position; 
         FIG. 5  shows a lock in the intermediate latched position during opening; and 
         FIG. 6  shows the opened lock. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows the interior of the lock  1  with its various components. The symmetrically designed hook  2 , which is not inserted herein in the lock  1 , can be seen first. On both sides  19 , of the lock  1  are located bolts  4 ,  3 . The former has a two-part design and has the locking pawl  7  in addition to the locking lever  6  on the side of the hook. The latter is configured as a rotary door latch  5  on the other side  20  and is rotatably mounted around the axis  33 . Contactless or contacted state sensors  18 ,  22  with actuators  15  are used to scan the open state of the lock and accordingly to control the opening and/or closing of the electromechanical lock. The cam  14  is moved against the locking pawl  7  by the reduction gear  27  and by the drive motor  11  for the opening function when the wheel  32  is turning. The cam  13  or the wheel  32 ′, which is concealed herein, is moved against the rotary door latch  5  by the drive motor  12  or by the reduction gear  26 . Reference number  25  identifies the base plate; all connection points are integrated into the housing of the lock  1 . 
       FIG. 2  illustrates the locking function, because here the hook  2  is shown in an intermediate latched stage, in which only one locked connection is made with the bolt  4 . The configuration of the hook  2  with the pin  30  on the front side  23 , and with the wedge  29  on the inside  24  of hook  2  is readily apparent. The latter is used to form a type of guide contour for the bolt  4 . The two bolts  3 ,  4  configured in the shape of a convex, elongated recess  17  in the region of the rotary door latch  5  are provided with a nose-like projection  28  and also with a likewise nose-like end  31  in the region of the locking lever  6 . The corresponding configuration of the rotary door latch  5  and locking lever  6  in the region of the latch surfaces  8  and  9  with the projections  35  and  37  on the side of the rotary door latch, and also the recess  34  and/or the projection  36  on the side of the locking pawl, and the recess  38 , are all readily apparent. The mortise and tenon joint  21  is exposed here. 
       FIG. 3  shows the lock  1  in the intermediate latched position during closing. The rotary door latch  5  is locked by the locking pawl  7 ; the locking surfaces  8 ,  9  rest against each other. Stated more precisely, the projection  36  on the side of the locking pawl is located in the recess  34  on the side of the rotary door latch between the two projections  35  and  37 . The locking lever  6  is released and rests against the hook  2 ; the mortise and tenon joint  21  is released. The cam wheels  13 ,  14  are in the basic position. 
     In order to arrive at the main latched position illustrated in  FIG. 4 , a force is exerted on the rotary door latch  5  via cam  13  and said latch is pulled into the main latched position, in which the hook  2  is pulled farther into the recess  17  of the rotary door latch  5  in comparison with the illustration in  FIG. 3 , and has reached its end position. In this case, the lock  1  pulls the hook  2  automatically from the intermediate latched position into the main latched position, whereupon the rotary door latch  5  and locking lever  6  are moved into a new latched position with respect to each other, in which the upper protrusion  37  on the side of the rotary door latch is now located underneath the projection  36  on the side of the locking pawl. 
     The lock  1  moves from the main latched position illustrated in  FIG. 4  into the intermediate latched position illustrated in  FIG. 5 . For this purpose, an opening pulse is transmitted by a sensor or by an appliance program to the cam  14 , which actuates the locking pawl  7  and opens this part of the lock. The hook  2  is thus caught in the locking lever  6 , the lock  1  moves into the intermediate latched position, in which the air, for example, can escape from a toaster. 
       FIG. 6  finally shows the open state, as was already shown earlier in  FIG. 1 , in which the rotary door latch  5  is unlocked, the opening pulse for the locking pawl  6  again comes from a sensor or an appliance program, the cam wheel  14  actuates again the locking lever  6  and opens the lock, the mortise and tenon joint  21  is maintained between the two parts of the bolt  4 , the locking lever  6  and locking pawl  7  mutually support each other, and the hook  2  is released.