Patent Publication Number: US-8991877-B2

Title: Door lock for the door of a household appliance

Description:
FIELD OF THE INVENTION 
     The present invention relates in general to door locks for household appliances, in particular washing machines, dishwashers, driers and cookers, and especially a lock for doors of household appliances with three connection contacts. 
     BACKGROUND OF THE INVENTION 
     Door locks which comprise a device for detecting a closed state of a household appliance door, a device for locking and optionally for unlocking the household appliance door and a device for detecting a locked state of the household appliance door are known in the household appliance sector. 
     The device for detecting the closed state establishes whether the household appliance door (also door in brief in the following) is closed. In this respect a closed state of the door is to be understood as meaning that the door closes the associated opening of the household appliance, if necessary with a sealing action, i.e. is not just ajar. It is assumed in the following that the door must be in the closed state if it is to be locked. It is of course also possible for the door not to be locked when it is in the closed state. 
     If the door is in the closed state, for example when starting up the household appliance, the device for locking can be actuated in order to lock the closed door, i.e. to bring it into a state in which the door cannot be opened. 
     If the door is locked, this is recognised by the device for detecting the locked state. 
     The device for detecting the closed state of the door provides a signal which indicates that the door is closed. This signal indicates to a control of the door lock that the door is closed and can now be locked. The device for locking is subsequently activated by the control in order to lock the door. The device for detecting the locked state of the door provides a signal which indicates that the door is locked. This signal indicates to the control that the door can no longer be opened and it is accordingly possible to operate the household appliance. 
     A known door lock for washing machines is illustrated in detail with reference to  FIGS. 1 to 3 : 
     The door lock, which is designated as a whole by  100 , has a housing shell  102  in which components which are described in the following are disposed. A housing lid, which is not represented, serves to close the equipped housing shell  102  and, together with the housing shell  102 , forms the housing of the door lock  100 . 
     A main slide  104 , which can be displaced horizontally in the figures, is disposed in the housing shell  102 . A main slide spring  106  acts on the main slide  104 . The main slide  104  has a stop  108 , the function of which is described in greater detail below. 
     A device of the door lock  100  for detecting the closed state of a household appliance door comprises a door contact switch  110 . The door contact switch  110  has a first door contact  112  and a second door contact  114 . If, as shown in  FIG. 1 , the first and second door contacts  112  and  114  are separated from one another, this indicates that the door is open. If, as shown in  FIGS. 2 and 3 , the first and second door contacts  112  and  114  contact one another, this indicates that the door is closed. 
     The first door contact  110  is disposed adjacent to a free end  116  of a first door contact conductor  118  formed as a leaf spring. The first door contact conductor  118  is biased to the right in the figures, i.e. the free end  116  exerts a force which is directed to the right. The end  120  of the first door contact conductor  118  which lies opposite the free end  116  is fastened to an inner end (not designated) of a first connection contact  122 . This can take place by gluing, soldering or riveting, for example. The first connection contact  122  is formed as a rigid, stiff conductor. The end  120  of the first connection contact  122  which lies opposite the connecting point with the first door contact conductor  118  serves the purpose of connection to a plug connection, which is not represented, of the household appliance. 
     The second door contact  114  is disposed at one end  124  of a second door contact conductor  126 . The second door contact conductor  126  is formed as a rigid, stiff conductor. Movements of the first and second door contacts  112  and  114  relative to one another are therefore possible on account of the flexible configuration of the first door contact conductor  118 . The end  128  of the second door contact conductor  126  which lies opposite the end  124  forms a second connection contact  128  and serves the purpose of connection to the above-mentioned plug connection. 
     A device of the door lock  100  for detecting a locked state of a household appliance door comprises a locking contact switch  130 . The locking contact switch  130  has a first locking contact  132  and a second locking contact  134 . The first locking contact  132  is disposed adjacent to a free end  136  of a first locking contact conductor  138  formed as a leaf spring. The first locking contact conductor  138  is biased to the left in the figures, i.e. therefore exerts a force to the left. The end  140  of the first locking contact conductor  138  which lies opposite the free end  136  is fastened to a third connection contact  150  by soldering, gluing or riveting, for example. The end of the third connection contact  150  which lies opposite the connecting point with the first locking contact conductor  138  serves the purpose of connection to the above-mentioned plug connection. 
     The second locking contact  134  is disposed at one end  144  of a second locking contact conductor  146 , which is formed as a stiff, rigid conductor. The opposite end of the second locking contact conductor  146  forms a fourth connection contact  142  and serves the purpose of connection to the above-mentioned plug connection. 
     A device of the door lock  100  for locking and unlocking the household appliance door comprises an electromagnetic actuator which is designated as a whole by  152 . The actuator  152  has a magnet  154  with an armature, which is not represented. The control of and energy supply to the actuator  152  takes place by way of a fifth connection contact  156  and a sixth connection contact  158 , which are formed as rigid, stiff conductors and serve the purpose of connection to the above-mentioned plug connection. The actuator  152  also has an actuating plunger  160  which is actively connected to the armature of the magnet  154  and can be actuated by this. 
     The locking and unlocking device also comprises a rotary slide  162  which serves to lock and unlock the main slide  104 . The rotary slide  162  is rotatably mounted in the housing shell  102 . A return spring  164 , the function of which is described in detail in the following, can act on the rotary slide  162  in accordance with the position thereof. The rotary slide  162  has a prolongation  165  which, as illustrated in detail in the following, can interact with the first locking contact conductor  138  and with the return spring  164 . A detent clip  166  can interact with the rotary slide  162  such that the rotary slide  162  is retained in a position which is suitable for locking, as described in detail in the following. 
     An electrical equivalent circuit diagram of the door lock  100  is shown in  FIG. 4 . 
     The operation of the door lock  100  is described in the following. 
       FIG. 1  shows the door lock  100  in a state in which the household appliance door is at least partly open, i.e. is neither in the closed nor in the locked state. In this state the main slide spring  106  acts on the main slide  104  such that this is pushed to the left. In this respect the main slide spring  106  is dimensioned such that, on account of an active connection of its end  116  with the structure  108 , the first door contact conductor  118  is retained against its bias in the position which is shown in  FIG. 1 . The first and second door contacts  112  and  114  are as a result separated from one another. The door contact switch  110  is therefore open and indicates that the household appliance door is not closed. 
     The rotary slide  162  is retained in the position which is shown in  FIG. 1  by a torsion spring, for example, which is not shown. In an embodiment which is not represented the return spring  164  is configured such that, for the state according to  FIG. 1 , it acts on the prolongation  165  and thereby retains the rotary slide  162  in the position which is shown in  FIG. 1 ; it is then possible to dispense with the above-mentioned torsion spring, which is not shown. Here the rotary slide  162  acts by means of a prolongation or stop  170  against the biasing force of the first locking contact conductor  138  such that the first locking contact conductor  138  is retained in the position which is shown in  FIG. 1 . The first and second locking contacts  132  and  134  are separated from one another, the locking contact switch  138  is therefore open and indicates that the household appliance door is not locked. 
       FIG. 2  shows the door lock  100  in a state in which the household appliance door is closed, but not (yet) locked. The closure of the household appliance door causes the main slide  104  to be moved to the right against the force of the main slide spring  106 . On account of its bias, the first door contact conductor  112  can in this case move such that the first and second door contacts  112  and  114  are brought into contact with one another. According to  FIG. 2 , this is achieved by the movement of the main slide  104  to the right terminating the active connection between the free end  116  of the first contact conductor  118  and the structure  108 . The door contact switch  110  is now closed and indicates that the household appliance door is closed. The states of the rotary slide  162  and of the locking contact switch  130  have not changed in any way here with respect to  FIG. 1 . 
       FIG. 3  shows the door lock  100  in a state in which the household appliance door is closed and locked. This state is achieved by activating the actuator  152  in order to achieve a movement of the actuating plunger  160  to the left. The actuating plunger  160  then acts on the prolongation  165  and rotates the rotary slide  162  clockwise until a structure (e.g. a link connection), which is not represented, of the rotary slide  162  interacts with the detent clip  166  such that the rotary slide  162  is retained in the position which is shown in  FIG. 3 . The active connection between the prolongation  170  and the first locking contact conductor  138  is then terminated. On account of its bias, the first locking contact conductor  138  takes up the position which is represented in  FIG. 3 . The first and second locking contacts  132  and  134  are brought into contact with one another. The locking contact switch  130  is therefore closed and indicates that the household appliance door is locked. 
     In order to enable the household appliance door to be opened, the household appliance door has to be unlocked. The actuator  152  is activated again for this purpose. The resultant movement of the actuating plunger  160  to the left rotates the rotary slide  162  clockwise slightly against the action of force of the return spring  164 , with the active connection of the structure, which is not shown, of the rotary slide  162  with the detent clip  166  being terminated and a rotation of the rotary slide  162  anti-clockwise being possible. The rotation of the rotary slide  162  back into its position which is represented in  FIG. 2  or  FIG. 1  takes place through the torsion spring, which was mentioned with reference to  FIG. 1  and is not represented, and initially on account of the active connection between the return spring  164  and the prolongation  165 . This rotation can also be effected by the return spring  164  alone, if this is configured such that it can also act on the prolongation  165  for the state according to  FIG. 1 . 
     The door lock  100 , which is a representative example of known door locks of the type initially mentioned, has disadvantages like the latter. In order to connect the door lock  100 , a plug connection with a total of 6 plug contact connection receptacles is required in order to accommodate the six connection contacts  122 ,  128 ,  142 ,  150 ,  156  and  158 . The resultant construction space for a plug connection is a disadvantage, as corresponding construction space must also be provided on the household appliance side. The number of plug contact receptacles on the plug connection side is also a disadvantage, because—on the account of the structural and material expenditure—it entails corresponding production costs. This also applies to the actual door lock  1 , where the total of six connection contacts entails corresponding construction space and expenditure. 
     A further disadvantage lies in the operational reliability of known door locks of this kind. If the actuator  152  is activated such that the rotary slide  162  is brought into the locking position which is shown in  FIG. 3 , although the door contact switch  110  is not closed, the door lock  100  may sustain damage if the household appliance door is closed when the door lock  100  is in a state of this kind. 
     Moreover, faulty operation of the household appliance as a whole may occur. If the actuator  152  is actuated as mentioned above, this results in the closure of the locking contact switch  130 . The closed state of the locking contact switch  130  usually indicates to the household appliance control that startup is permissible. If, however, the household appliance door is not closed in a situation of this kind, injuries may occur through a drum rotating in the household appliance, water may escape in the case of household appliances carrying water and heat may escape in the case of driers and cookers. 
     OBJECT OF THE INVENTION 
     The object of the present invention is to provide a door lock for household appliances which can be produced in a simpler and more cost-effective way and which, moreover, also works more reliably. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The present invention provides a door lock in order to achieve the above object. 
     A third device for detecting a locked state of the door is preferably provided. 
     The third device may be connected to the series connection of the first and second devices. 
     The second device also serves to unlock the door. 
     It is particularly preferable for the door lock as a whole to have just three connection contacts for electrical connections to the household appliance. 
     In this respect the first and second devices may be electrically connected to first and second connection contacts, respectively, of the door lock. 
     When using the third device, this can be electrically connected to a third connection contact of the door lock. 
     The first device preferably comprises a door contact switch with first and second contacts. 
     The first door contact may be disposed at a free end of a resiliently biased first door contact conductor. 
     The first door contact may also be connected to a first connection contact of the door lock in an electrically conductive manner. 
     The second device may be connected to the second door contact in an electrically conductive manner. 
     In one preferred embodiment the door lock comprises a main slide, which has or can take up a first position for a closed state of the door, and a stop region in order to interact with the first device. 
     Provision is in this case made for the main switch, in the first position, to retain the first and second door contacts in positions which are separate from one another. The main slide may also have a second position which indicates an open state of the door, in which case the main slide, in the second position, releases the first door contact for contacting the second door contact. 
     A main slide spring is preferably used in order to bias the main slide into the first position or into the second position. 
     The second device may comprise an actuator which has first and second actuator connections. 
     An electromagnetic actuator is preferably used. 
     The first actuator connection may be connected to the first device in an electrically conductive manner. 
     The second actuator connection may be connected to a second connection contact of the door lock in an electrically conductive manner. 
     The second device preferably comprises a rotary member and an actuating member by means of which the rotary member can be actuated when locking takes place. 
     The rotary member may have a lock-in structure which can interact with a detent member. 
     The rotary member may have a stop for interaction with the third device. 
     A lever provided on the rotary member is provided to interact with the actuator. 
     The third device preferably comprises a locking contact switch with first and second locking contacts. 
     The first locking contact may be disposed at a free end of a resiliently biased first locking contact conductor and/or connected to a third connection contact of the door lock. 
     The second locking contact is preferably connected to the second device in an electrically conductive manner. 
     The second device can release the first locking contact when locking takes place such that the first and second locking contacts can contact one another. 
     When the door is in an unlocked state the second device retains the first and second locking contacts in positions which are separate from one another. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present description and in particular the following description of preferred embodiments refer to the accompanying figures, in which: 
         FIG. 1  shows a known door lock with an unclosed and unlocked door, 
         FIG. 2  shows the known door lock of  FIG. 1  with a closed door, 
         FIG. 3  shows the known door lock of  FIG. 1  with a closed and locked door, 
         FIG. 4  is a schematic representation of a circuit arrangement for use with the known door lock according to  FIGS. 1 to 3 , 
         FIG. 5  shows an embodiment of the door lock according to the invention with an unclosed and unlocked door, 
         FIG. 6  shows the embodiment of  FIG. 5  with a closed and unlocked door, 
         FIG. 7  shows the embodiment of  FIG. 5  with a closed and locked door, 
         FIG. 8  is a schematic representation of a circuit arrangement for use with the door lock according to the invention, and 
         FIG. 9  is a schematic representation of a circuit arrangement for use with a known door lock with a thermoelectric actuator. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     A preferred embodiment of the door lock according to the invention and variants thereof are described with reference to  FIGS. 5 to 7 . 
     The door lock  1  comprises a housing shell  2 , in which components of the door lock  1  which are mentioned in the following are disposed. The housing shell  2  can be closed by a housing lid, which is not shown and which, together with the housing shell  2 , forms a housing of the door lock  1 . 
     A main slide  4  is disposed in the housing shell  2  such that it can move horizontally in the figures. A main slide spring  6  acts on the main slide  4 , pushing the main slide  4  to the right according to the figures. A stop region  8  is provided at the end of the main slide  4  which lies opposite its side which interacts with the main slide spring  6 . As shown in the figures, the stop region  8  may be provided by this end of the actual main slide  4 . The stop region  8  may also be provided in the form of a structure on the main slide  4  which extends substantially perpendicularly to the directions of movement of the main slide  4 . 
     The door lock  1  has a door contact switch  10 . The door contact switch  10  comprises a first door contact  12  and a second door contact  14 . The first door contact  12  is disposed on a first door contact conductor  16 . The first door contact conductor  16  is configured as a resilient element, for example in the form of a leaf spring. According to the figures, the first door contact conductor  16  is biased to the right. The first door contact  12  is disposed on the first door contact conductor  16  such that movements of the first door contact conductor  16  which are described in the following can bring the first and second door contacts  12  and  14  into contact with one another and separate them from one another. 
     As illustrated in the following, a free end  18  of the first door contact conductor  16  can interact with the stop region  8 . The end  22  of the first door contact conductor  16  which lies opposite the free end  18  is connected to an inner end of the first connection contact  20  by soldering, gluing or riveting, for example. The arrangement of the second door contact switch  14  is described below. In this respect “inner” is understood as meaning the region and components which are not accessible from outside when the housing is closed (i.e. housing shell closed by housing lid); the equivalent applies to “outer”. 
     The door lock  1  has a device for locking and unlocking a household appliance door with an actuator  24  which is formed as an electromagnetic actuator. The actuator  24  comprises a magnet  26  whose armature, which is not represented, interacts with an actuating member  28 . Activation of the actuator  24  by energising the magnet  26  gives rise to movements of the actuating member  28  to the left according to the figures. 
     The actuator  24  has a first actuator connection  30  and a second actuator connection  32  for supplying energy. The first actuator connection  30  is connected to the second door contact  14  in an electrically conductive manner. As represented in the figures, this can be achieved, for example, by forming the first actuator connection  30  as a conductor which extends away from the actuator  24  and the free, outer end of which allows the second door contact  14  to be disposed. 
     The second actuator connection  32  is connected to a second connection contact  34  in an electrically conductive manner. This can be achieved by forming the second actuator connection  32  as a conductor which extends away from the actuator  24  and the free end of which serves as a third connection contact  34 . It is also possible to provide the second actuator connection  32  as a connection point which is formed on the actuator  24  and is connected to an inner end of an electrical conductor which provides the second connection contact  34  at its opposite, outer end. 
     A rotary member  36  is also provided. The rotary member  36  can be actuated by the actuator  24 , with rotations of the rotary member  36  thereby effected serving to lock and unlock the main slide  4 . The rotary member  36  can rotate clockwise and anti-clockwise, with a spring, which is not represented, biasing the rotary member  36  in the anticlockwise direction. 
     The rotary member  36  has a lever  38  whose free end serves to actuate the rotary member  36  through the actuating member  28 . The rotary member  36  also has a stop which is formed as a prolongation  40 . A lock-in structure  42  which is formed or disposed on the rotary member  36  interacts with a detent clip  44 . 
     The door lock  1  also has a locking contact switch  46 . The locking contact switch  46  comprises a first locking contact  48  and a second locking contact  50 . The first locking contact  48  is disposed on a resilient first locking contact conductor  52  which is formed as a leaf spring, for example. The first locking contact conductor  52  is fixed and connected to an inner end of a third connection contact  56  in an electrically conductive manner at its end  54  which is the lower end in the figures. The third connection contact  56  may also be provided by a corresponding, longer configuration of the actual first locking contact conductor  52 . The opposite end  58  of the first locking contact conductor  52  is a free end which can move as described in the following. Movements of the end  58  enable the first and second locking contacts  48  and  50  to be brought into contact with one another and separated from one another. 
     The second locking contact  50  is disposed on a second locking contact conductor  60  opposite the first locking contact  48 . The second locking contact conductor  60  is connected to the first connection contact  20  in an electrically conductive manner and, as represented in the figures, preferably formed in one piece with this. According to the figures, the end  22  of the first door contact conductor  16  is connected to the connection contact  20  by connecting the end  22  to the second locking contact conductor  60 . 
     For a basic understanding of the mode of operation of the door lock  1 , reference is made to  FIG. 8 , which can be conceived as an electrical equivalent circuit diagram with regard to the door contact switch  10 , the locking contact switch  46  and the actuator  24 . The door contact switch  10  and the actuator  24  are electrically connected in series between the first connection contact  20  and the second connection contact  34 . The locking contact switch  46  is connected between the first connection contact  20  and the third connection contact  56 . 
     The door contact switch  10  is open as long as the household appliance door is not closed. The actuator  24  cannot then be activated by supplying energy by way of the first and second connection contacts  20  and  34 . 
     If the household appliance door is closed, the door contact switch  10  closes in response to this. The first and second actuator connections  30  and  32  are then connected to the first and second connection contacts  20  and  34  in an electrically conductive manner. In this state the actuator  24  can be controlled by supplying energy by way of the first and second connection contacts  20  and  34 , for example in the form of a pulse-like operation. As described in detail below, activation of the actuator  24  to lock the household appliance door causes the locking contact switch  46  to close. This is indicated in  FIG. 8  by the broken line. 
     The locking contact switch  46  closed in response to locking establishes an electrical connection between the first and third connection contacts  20  and  56 . The electrical connection of the first and third connection contacts  20  and  56  which is thus established indicates to a household appliance control that the household appliance door is locked and startup can take place. 
     The first connection contact  20  is preferably connected to earth. The second connection contact  34  is preferably connected to an electrical connection of a household appliance control by way of which control signals (e.g. pulse signals) can be supplied to the actuator  34 . The third connection contact  56  is preferably connected to a connection of a household appliance control which has a predetermined potential which preferably differs from earth. If the locking contact switch  46  is closed, current flows between the first and third connection contacts  20  and  56 . This flow of current indicates the locked state of the household appliance door. 
     The mode of operation of the door lock  1 , as illustrated in  FIGS. 5 to 7 , is described in greater detail in the following. 
     The door lock  1  is in the state which is shown in  FIG. 5  when the household appliance door is neither completely closed nor locked. In this state the main slide spring  6  retains the main slide  4  in the represented position. The stop region  8  and the free end  18  of the first door contact conductor  16  then interact such that the first door contact conductor  16  is retained in the represented position against its bias. The first and second door contacts  12  and  14  are in this case separated from one another. 
     This indicates that the household appliance door is not closed. Any activation of the actuator  40  is impossible in this case. 
     When the door lock  1  is in the state according to  FIG. 5  the free end of the lever  38  lies against the actuating member  28  on account of the action of force of the above-mentioned torsion spring, which is not represented, of the rotary member  36 . The prolongation  40  and the free end  58  of the first locking contact conductor  52  then interact such that the first locking contact conductor  52  is retained in the represented position against its bias. The first and second locking contacts  48  and  50  are separated from one another. This indicates that the household appliance door is not locked. Current cannot flow between the first and third connection contacts  20  and  56 . 
     The state of the door lock  1  which is represented in  FIG. 6  corresponds to a situation in which the household appliance door is closed, but not locked. The closure of the household appliance door causes the main slide  4  to move to the right against the pressure force of the main slide spring  6 . The active connection between the stop region  8  and the free end  18  of the first door contact conductor  16  is then terminated. The bias of the first door contact conductor  16  causes a movement into the position which is represented in  FIG. 6 . The first and second door contacts  12  and  14  are as a result brought into electrically conductive contact with one another. The actuator  24  can be controlled on account of the resultant electrical connection between the first and second connection contacts  20  and  34 . No changes occur with regard to the rotary member  36  and the locking contact switch  46  when the door lock  1  is in this state. 
     The state of the door lock  1  which is represented in  FIG. 7  corresponds to a situation in which the household appliance door is closed and locked. In order to bring the door lock  1  into a state in which the household appliance door is locked, the actuator  24  is activated, which is possible on account of the electrical connection of the first and second connection contacts  20  and  34  by way of the closed door contact switch  10 . The activation of the actuator  24  causes a movement of the actuating member  28  to the left, preferably in a pulse-like manner. The rotary member  36  is then rotated clockwise on account of the active connection with the actuating member  28  and the free end of the lever  38 . The rotation of the rotary member  36 , which also results in a displacement of the prolongation  40 , causes the first locking contact conductor  52  to move on account of its bias into the position which is represented in  FIG. 7 . It is then possible for the active connection between the prolongation  40  and the free end  58  of the first locking contact conductor  52  to be terminated or, as shown in  FIG. 7 , for the prolongation  40  and the end  58  to remain in contact. When the first locking contact conductor  52  is in this position, the first and second locking contacts  48  and  50  contact one another in an electrically conductive manner, so that there is an electrically conductive connection between the first and third connection contacts  20  and  56 . 
     The rotation of the rotary member  36  also causes the lock-in structure  42  and the detent clip  44  to interact such that the rotary member  36  is retained in the position which is shown in  FIG. 7 . 
     The actuator  24  is activated again in order to unlock the household appliance door. 
     The resultant, preferably pulse-like, movement of the actuating member  28  exerts a force on the rotary member  36  clockwise by way of the lever  38 . This action of force, is which can cause the rotary member  36  to rotate further clockwise, results in the lock-in structure  42  and the detent clip  44  interacting such that the active connection which retains the rotary member  36  in the position which is shown in  FIG. 7  is terminated. The rotary member  36  is subsequently brought by the above-mentioned spring, which is not represented, anticlockwise into the position which is shown in  FIG. 5 . The prolongation  40  then pushes the end  58  of the first locking contact conductor  52  into the position according to  FIG. 6 . The electrically conductive connection between the first and second locking contacts  48  and  50  is terminated. The absence of an electrical connection between the first and third connection contacts  20  and  56  indicates that the household appliance door is not locked (any more). 
     After unlocking the household appliance door, where the door lock  1  is in the state which is shown in  FIG. 6 , the household appliance door can be opened. Opening of the household appliance door causes the main slide spring  6  to push the main slide  4  out of the position which is shown in  FIG. 6  into the position which is shown in  FIG. 5 . The stop region  8  then moves the free end  18  of the first door contact conductor  16  into the position which is shown in  FIG. 5 . The first and second door contacts  12  and  14  are then separated from one another. There is no electrically conductive connection between the first and third connection contacts  20  and  34 . Activation of the actuator  34  is not possible (any more). 
     Diverging from the embodiment which is represented in  FIGS. 5 to 7 , it is possible to use, instead of the separated first door contact conductor  16  and second locking contact conductor  60 , a conductor which is comparable with the first door contact conductor  16  and on which both the first door contact and the second locking contact are disposed. 
     It is also possible to use, instead of separate conductors for the connection contacts, one-piece conductors which provide, as integrated units, the connection contacts and door contact and locking contact conductors or actuator connections. 
     Provision is also made to firmly connect the first locking contact  48  to the rotary member  36  and dispose it such that a rotation of the rotary member  36  for locking the household appliance door brings the first and second door contacts into contact with one another. 
     Furthermore, embodiments are provided in which individual, a plurality of or all active principles are reversed in comparison with the embodiment of  FIGS. 5 to 7 , as far as this is possible. For example, one embodiment can have a locking contact switch whose open state (i.e. locking contacts  48  and  50  contact one another) indicates that the household appliance door is locked, while its closed state (i.e. locking contacts  48  and  50  do not contact one another) indicates an unlocked household appliance door. 
     The door lock according to the invention has various advantages. 
     The electrical series connection of the door contact switch and the actuator ensures that the actuator is also only actually activated when the household appliance door is closed. 
     Moreover, the number of connection contacts which are used is distinctly reduced. This results in a lower number of components, a reduced material requirement, a simpler structure and therefore in reduced production costs. The construction space in the region of the connection contacts is in addition decreased. However the reduced number of connection contacts also results in a decrease in the construction space required overall. The advantages obtained from the reduced number of connection contacts also apply to the connection which is provided on the household appliance side. 
     It is, nevertheless, still possible to detect the positions of the door contact switch  10  and/or of the locking contact switch  46  in order to establish whether the door contact switch  10  and the locking contact switch  46  are closed or open. 
     A further advantage becomes apparent in view of the following statements. Many household appliance manufacturers fit their household appliances according to price category with simple door locks whose doors are locked by means of a thermoelectric actuator (e.g. PTC element), or with door locks in the case of which doors are locked by means of an electromagnetic actuator. 
     As illustrated in  FIG. 9 , the simpler door locks with thermoelectric actuators have three connection contacts I, II and III. In contrast to the door locks discussed here, these door locks do not comprise any devices for establishing whether a household appliance door is closed.  FIG. 9  represents in schematic form an electrical equivalent circuit diagram for a known door lock with a thermoelectric actuator TA in the form of a PTC element and a device DV for detecting a locked state. 
     It has until now been necessary, depending on whether door locks with a thermoelectric actuator or with an electromagnetic actuator are to be used, to provide various connection devices on the household appliance side, namely on the one hand connections with three contacts and on the other connections with six contacts. This is no longer necessary with the present invention. It is instead possible to use identical connections on the household appliance side irrespective of the type of door lock which is to be used. The present invention enables, for example, one and the same household appliance to be fitted either with a door lock according to the invention or with a known door lock with a thermoelectric actuator, without structural changes on the household appliance side being required in this respect.