HOUSEHOLD DISHWASHER

Description

[0001] The present invention relates to a household dishwasher with a lower and upper dishware holder for receiving dishes and with a lifting device for lifting the lower dishware holder from a starting position, in which the lower dishware holder is completely displaced out of the washing container, to an end position, in which the lower dishware holder is completely displaced out of the washing container with the aid of the lifting device and raised approximately to the level of the upper dishware holder, and for lowering the lower dishware holder from the end position to the starting position, wherein the lifting device comprises a spring element for assisting the raising and lowering of the lower dishware holder with the aid of an assisting force and a spring preload adjusting unit which adapts the assisting force to a loading state of the lower dishware holder by adjusting a spring preload of the spring element.

[0002] A household dishwasher comprises a wash tub and at least one dish receptacle that can be moved into and out of the wash tub. In particular, such a household dishwasher can comprise several dish receptacles arranged one above the other, such as a lower basket, an upper basket, or a cutlery drawer. Since the lower basket is located near a base of the wash tub, loading or unloading the lower basket requires the user to kneel or bend down towards the lower basket. To simplify loading and unloading the lower basket, a lifting mechanism can be provided. There are passive lifting mechanisms that operate with the aid of a spring element, and active lifting mechanisms that have a drive element, for example in the form of an electric motor.

[0003] The document DE 20 2009 004 771 U1 discloses a device for adjusting the height of a shelf guided in a household appliance via at least one pull-out guide. The device has at least one guide rail, on which the shelf can be guided and pulled out in a pull-out direction, and a height adjustment mechanism that can be secured to opposite side walls of the household appliance. The height adjustment mechanism has two arms, each of which has a first end rotatably mounted parallel to the plane of the side walls and arranged parallel and spaced from one another. Two guide rails can be secured to respective second ends of the arms so that they can be rotated parallel to the plane of the side walls in such a way that the guide rails can be raised from a lower position in the household appliance to an upper position at least partially in front of the household appliance.An energy storage device can be attached to at least one of the opposite side walls of the household appliance. This energy storage device is operatively connected to one of the arms attached to this side wall in such a way that the energy stored in the energy storage device can support the raising or lowering of the guide rails. The energy storage device can be designed as a tension spring.

[0004] Document EP 3 297 511 A1 discloses a mechanism for unlocking a raised lower dishware receptacle in a dishwasher. The mechanism for unlocking the raised lower dishware receptacle is provided in an assembly for a dishwasher, which is designed to raise the lower dishware receptacle from a lower position to an upper position and to lock the raised lower dishware receptacle in the upper position. The lifting device comprises a spring-loaded pivot arm assembly, which is attached at one end to the wash tub of the dishwasher and at another end to the lower dishware receptacle, in order to raise the lower dishware receptacle from the lower position within the wash tub to the upper position at least partially outside the wash tub.The lifting device further includes a locking mechanism disposed between the spring-loaded pivot arm assembly and the lower dish support and configured to lock the spring-loaded pivot arm assembly when the lower dish support has been raised to the upper position, thereby securing the lower dish support in the upper position. The mechanism for unlocking the raised lower dish support includes a lever extending from a front side of the lower dish support along each side of the lower dish support to the locking mechanism located on a respective side of the lower dish support.User operation of the lever on the front of the raised lower rack causes each end of the lever to act on the locking mechanism located on either side of the lower dish rack to unlock the raised lower dish rack so that it can be lowered to its lower position.

[0005] US 3,799,640 A discloses a dishwasher construction that prevents tipping by ensuring that only one dish basket can be fully extended at a time. A positioning dual-crank lever limiting rod for the dish baskets is pivotally mounted at its center on a side wall of the washing tub and is spring-loaded in a dead center position so that cam surfaces on the upper and lower arms of the positioning dual-crank lever limiting rod engage cam-following actuating elements on the rear of the upper and lower dish baskets, respectively, so that pivoting of the positioning dual-crank lever limiting rod in a first direction, for example, prevents outward movement of the upper dish basket when the lower dish basket has been moved to its fully extended position.

[0006] The document DE 10 2012 107 993 A1 discloses a sliding / pivoting mechanism for a shelf of a piece of furniture or a household appliance for pulling out and lifting the shelf from a body of the furniture or household appliance. The sliding / pivoting mechanism has at least two pivot arms, each pivoted to at least one of the side walls of the body with a first end parallel to the plane of the side walls and arranged parallel and spaced apart from one another. A guide rail is pivotably mounted parallel to the plane of the side walls at respective second ends of the pivot arms in such a way that the guide rail can be pivoted from a lower position within the body to a raised, upper position at least partially outside the body. At least one guide rail is provided, which is linearly displaceable in the respective guide rail and to which the shelf is attached.The sliding-swivel mechanism has a locking mechanism arranged on the guide rail and on one of the swivel arms to prevent simultaneous swivel and sliding movement of the guide rail.

[0007] The document DE 10 2015 201 806 A1, the document EP 1 066 789 A1, the document WO 2005 / 104924 A1, the document US 6,247,771 B1, the document US 2006 / 0066189 A1, the document US 2007 / 0035220 A1 and the document US 2010 / 0045152 A1 each show lifting mechanisms which operate with the aid of an electric motor as a drive element.

[0008] Against this background, it is an object of the present invention to provide an improved household dishwasher.

[0009] Accordingly, a household dishwasher is proposed with a lower dishware receptacle for receiving dishes and with a lifting device for lifting the lower dishware receptacle from a starting position, in which the lower dishware receptacle is completely displaced from the washing container, to an end position, in which the lower dishware receptacle is completely displaced from the washing container with the aid of the lifting device and raised approximately to the level of the upper dishware receptacle, and for lowering the lower dishware receptacle from the end position to the starting position. The lifting device comprises a spring element for assisting the raising and lowering of the lower dishware receptacle with the aid of an assisting force and a spring preload adjustment unit which adapts the assisting force to a loading state of the lower dishware receptacle by adjusting a spring preload of the spring element.The spring preload adjustment unit has an actuating element in the form of a stepper motor for adjusting the spring preload of the spring element.

[0010] Because the spring preload of the spring element can be adjusted using the spring preload adjustment unit, it is possible to constantly adjust the support force so that a comfortable operating force can be achieved for the user when raising and lowering the lower dishwashing basket. This increases operating comfort.

[0011] The household dishwasher preferably comprises a washing container in which the dishware holder can be accommodated. In particular, the household dishwasher has a plurality of dishware holders. For example, three dishware holders can be arranged one above the other in the washing container, wherein a lower dishware holder or a lower basket, an upper dishware holder or an upper basket and a cutlery drawer can be provided. In particular, the lower dishware holder can be moved from the starting position to the end position and vice versa with the aid of the lifting device. In the end position, the lower dishware holder is preferably arranged approximately at the height of the upper dishware holder. This enables easy loading and unloading of the lower dishware holder.

[0012] In this case, the fact that the spring element "supports" the raising and lowering is to be understood in particular to mean that the lifting is not carried out solely by the assisting force of the spring element, but that the user applies an actuating force to the lower dishware holder in order to move it from the starting position to the end position. Conversely, when moving the lower dishware holder from the end position to the starting position, the spring preload is changed such that the user does not have to work excessively against the assisting force to move the lower dishware holder from the end position to the starting position. Thus, the actuating force is particularly preferably independent of the load state of the lower dishware holder. In particular, the actuating force is consistent or constant.

[0013] "Adjusting" the spring preload specifically means that the spring element is either stretched or compressed. The greater the spring preload, the greater the assist force. "Adapting" the assist force to the load of the lower dishware holder means that the assist force increases or becomes greater as the load of the lower dishware holder increases. Conversely, the assist force decreases as the load decreases.

[0014] The stepper motor can be a linear motor, for example. However, the stepper motor can also be a rotary motor. If the actuator is a linear motor, the spring element can be directly coupled to the actuator, for example. The actuator can then stretch or compress the spring element to increase or decrease the preload.

[0015] According to a first embodiment, the household dishwasher further comprises a sensor device for detecting the loading state of the lower dishware holder.

[0016] Preferably, the sensor device detects the load condition indirectly. This means that the load condition can be detected, for example, by detecting the weight force acting on the spring element of the items held in the lower dishware holder. Alternatively, the load condition of the lower dishware holder can also be detected in another way, for example, optically.

[0017] According to a further embodiment, the sensor device comprises a strain gauge.

[0018] The sensor device can be part of the spring element. For example, the spring element has a cylindrical spring section with hook-shaped suspension sections provided at the ends. For example, the sensor device can be arranged in the form of one or more strain gauges between one of the suspension sections and the spring section. In particular, the strain gauge can be glued to the spring element.

[0019] According to a further embodiment, the sensor device comprises a torque sensor.

[0020] The torque sensor is preferably provided on a coupling disc, which is subjected to spring preload by means of the spring element. The coupling disc can, for example, be permanently connected to a swivel arm of the lifting device. In this case, the spring element applies a torque to this swivel arm, and the torque sensor can detect the acting torque.

[0021] According to a further embodiment, the spring preload adjustment unit has an adjusting disc which is coupled to the actuating element in the form of a stepper motor and the spring element, wherein the spring element is coupled off-center to the adjusting disc.

[0022] In particular, the adjusting element, in the form of a stepper motor, can rotate the adjusting disc about a rotational axis. "Off-center" in this case means spaced from the rotational axis of the adjusting disc. For example, the adjusting disc can have a cam or a bolt into which the spring element is hooked with one of its hooking sections. The spring preload adjustment unit can be attached, for example, to the washing tub of the household dishwasher.

[0023] According to a further embodiment, the spring element is a tension spring, wherein the spring preload adjusting unit stretches the spring element to increase the spring preload.

[0024] This means that to increase the spring preload, the spring element is stretched. The spring preload adjustment unit can move the spring element from an initial state, in which the spring preload is minimal, through any number of intermediate states to a final state, in which the spring preload is maximum.

[0025] According to a further embodiment, the spring preload adjustment unit has an engagement element which is coupled to the actuating element in the form of a stepper motor by means of a threaded spindle.

[0026] The threaded spindle can be part of the actuator in the form of a stepper motor. In particular, the actuator in the form of a stepper motor can cause the threaded spindle to rotate. The engagement element can be a nut mounted on the threaded spindle, which moves linearly along the threaded spindle as the spindle rotates.

[0027] According to a further embodiment, the spring element is arranged between the engagement element and a lever arm of a coupling disc.

[0028] As previously mentioned, the coupling disc can be connected, for example, to one of the swivel arms of the lifting device. The sensor device with the torque sensor can be provided on the coupling disc.

[0029] According to a further embodiment, the spring element is a compression spring, wherein the spring preload adjusting unit compresses the spring element to increase the spring preload.

[0030] In particular, the spring element is compressed by the engagement element moving toward the lever arm of the coupling disc. To release the spring element, the engagement element moves away from the lever arm again.

[0031] Further possible implementations of the household dishwasher also include combinations of features or embodiments described above or below with respect to the exemplary embodiments that are not explicitly mentioned. In this case, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the household dishwasher.

[0032] Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the exemplary embodiments of the household dishwasher described below. The household dishwasher is explained in more detail below using preferred embodiments with reference to the accompanying figures.

[0033] It shows Fig. 1 is a schematic perspective view of an embodiment of a household dishwasher; Fig. 2 is a schematic side view of the household dishwasher according to Fig. 1; Fig. 3 a further schematic side view of the household dishwasher according to Fig. 1 ; Fig. 4 a schematic view of an embodiment of a drive mechanism of a lifting device for the household dishwasher according to Fig. 1 ; Fig. 5 a further schematic view of the drive mechanism according to Fig. 4 ; Fig. 6 a further schematic view of the drive mechanism according to Fig. 4 ; Fig. 7 schematically shows a diagram of a force curve when lifting a lower dishware holder of the household dishwasher according to Fig. 1 ; Fig. 8 a schematic view of another embodiment of a drive mechanism of a lifting device for the household dishwasher according to Fig. 1 ; Fig. 9 a further schematic view of the drive mechanism according to Fig. 8 ; Fig. 10 a further schematic view of the drive mechanism according to Fig. 8and Fig. 11 schematically shows a diagram of a force curve when lifting a lower dishware holder of the household dishwasher according to Fig. 1 .

[0034] In the figures, identical or functionally identical elements have been given the same reference numerals unless otherwise stated.

[0035] The Fig. 1 shows a schematic perspective view of an embodiment of a household dishwasher 1. The household dishwasher 1 comprises a washing container 2, which can be closed by a door 3, in particular in a watertight manner. For this purpose, a sealing device can be provided between the door 3 and the washing container 2. The washing container 2 is preferably cuboid-shaped. The washing container 2 can be arranged in a housing of the household dishwasher 1. The washing container 2 and the door 3 can form a washing chamber 4 for washing dishes.

[0036] Door 3 is in the Fig. 1shown in its open position. The door 3 can be closed or opened by pivoting about a pivot axis 5 provided at a lower end of the door 3. With the help of the door 3, a loading opening 6 of the washing container 2 can be closed or opened. The washing container 2 has a base 7, a ceiling 8 arranged opposite the base 7, a rear wall 9 arranged opposite the closed door 3 and two side walls 10, 11 arranged opposite one another. The base 7, the ceiling 8, the rear wall 9 and the side walls 10, 11 can be made, for example, from a stainless steel sheet. Alternatively, the base 7 can, for example, be made from a plastic material.

[0037] The household dishwasher 1 further comprises at least one dishware receptacle 12 to 14. Preferably, several, for example three, dishware receptacles 12 to 14 can be provided, wherein the dishware receptacle 12 can be a lower dishware receptacle or a lower basket, the dishware receptacle 13 can be an upper dishware receptacle or an upper basket, and the dishware receptacle 14 can be a cutlery drawer. Fig. 1 As further shown, the dishware receptacles 12 to 14 are arranged one above the other in the washing container 2. Each dishware receptacle 12 to 14 can be selectively moved into or out of the washing container 2. In particular, each dishware receptacle 12 to 14 can be pushed or moved into the washing container 2 in an insertion direction E (arrow) and pulled or moved out of the washing container 2 in an extension direction A (arrow) opposite to the insertion direction E (arrow).

[0038] As the Fig. 2 and 3show, the lower dishware holder 12 is guided in the washing container 2 with the aid of a guide device 15. The guide device 15 can be a so-called telescopic rail. Preferably, such a guide device 15 is provided on both sides of the lower dishware holder 12. With the aid of the guide devices 15, the lower dishware holder 12 can be moved out of the washing container 2 in the pull-out direction A (arrow) and moved into the washing container 2 in the push-in direction E (arrow). The lower dishware holder 12 usually represents a lower dishware holder or a lower basket.

[0039] The household dishwasher 1 further comprises a lifting device 16 with the aid of which the lower dishware holder 12 is lifted from a Fig. 2 shown starting position AP into a position shown in the Fig. 3shown end position EP. Conversely, the lower washware holder 12 can be moved from the starting position AP back to the end position EP with the aid of the lifting device 16. In the starting position AP and in the end position EP, the lower washware holder 12 is completely moved out of the washing container 2 in the pull-out direction A (arrow) with the aid of the guide devices 15.

[0040] In the end position EP, the lower dishware holder 12 is raised by means of the lifting device 16 approximately at the height of the Fig. 2 and 3not shown upper dishware receptacle 13, so that a user does not have to bend down to load and unload the lower dishware receptacle 12. Preferably, the household dishwasher 1 comprises two such lifting devices 16, which are arranged on the opposite side walls 10, 11 of the washing tub 2. In the following, however, reference is made to only one lifting device 16. The lifting device 16 supports the lifting of the lower dishware receptacle 12 from the starting position AP to the end position EP with an assisting force FU (arrow). However, the lifting device 16 does not automatically lift the lower dishware receptacle 12 from the starting position AP to the end position EP or lower it from the end position EP to the starting position AP, but the user additionally applies an actuating force FB (arrow) to the lower dishware receptacle 12.

[0041] The lifting device 16 can be a Fig. 2 and 3 not shown. The drive element can be a passive drive element. A "passive" drive element is understood here to be a drive element to which no external energy is supplied. Such a passive drive element can be, for example, a spring element. In contrast, an "active" drive element is understood to be a drive element to which external energy is supplied. For example, an electric motor is an active drive element.

[0042] The lifting device 16 can comprise the guide device 15. Furthermore, the lifting device 16 comprises a first pivot arm 17 and a second pivot arm 18. In the starting position AP, the pivot arms 17, 18 are arranged parallel to each other and extend in the orientation of the Fig. 2from top to bottom. The pivot arms 17, 18 are each rotatably connected to the washing container 2, in particular to one of the side walls 10, 11 of the washing container 2, by a respective first end section. Furthermore, the pivot arms 17, 18 are each rotatably connected to the guide device 15 by a second end section facing away from the first end section.

[0043] The lifting device 16 further comprises a Fig. 4 to 6shown drive mechanism 19A. The drive mechanism 19A comprises a spring element 20. The spring element 20 is a cylindrical spring. The spring element 20 can be a tension spring. The spring element 20 comprises a spring section 21, which is designed, for example, as a spiral coil. Furthermore, the spring element 20 comprises two hook-shaped suspension sections 22, 23, with which the spring element 20 can be connected, for example, to the lifting device 16 and / or the washing container 2. The spring section 21 is arranged between the two suspension sections 22, 23.

[0044] The drive mechanism 19A further comprises a sensor device 24 for detecting a loading state of the lower dishware receptacle 12. The "loading state" is understood here to mean the degree to which the lower dishware receptacle 12 is filled with dishes and / or the weight of the dishes held in the lower dishware receptacle 12. The sensor device 24 can, for example, comprise a strain gauge 25. The sensor device 24 can be part of the spring element 20 or arranged on the spring element 20. As shown in the Fig. 4 to 6 As shown, the sensor device 24 can be arranged between the spring section 21 and the suspension section 23.

[0045] The drive mechanism 19A further comprises a spring preload adjustment unit 26, with the aid of which a spring preload FV (arrow) of the spring element 20 can be adjusted. The spring preload adjustment unit 26 comprises a circular adjusting disc 27 and an actuating element 28 in the form of a stepper motor, with the aid of which the adjusting disc 27 can be rotated about a rotational axis 29. Off-center on the adjusting disc 27, i.e., spaced from the rotational axis 29, a cam or a bolt 30 is provided, into which the suspension section 22 of the spring element 20 is suspended. For example, the spring preload adjustment unit 26 can be firmly connected to the rinsing container 2. The suspension section 23 of the spring element 20 is suspended in a further cam or a bolt 31. The bolt 31 can, for example, be coupled to one of the pivot arms 17, 18.

[0046] The functionality of the drive mechanism 19A is explained below. With the help of the actuating element 28 in the form of a stepper motor, the adjusting disc 27 can be set in rotation. The direction of rotation D (arrow) of the adjusting disc 27 can be oriented clockwise. However, the direction of rotation D (arrow) can also be oriented counterclockwise. In this case, the spring element 20 is actuated by a Fig. 4 shown initial state AZ, in which the spring preload FV (arrow) is minimal, is brought continuously via any number of intermediate states ZZ to a final state EZ in which the spring preload FV (arrow) is maximum.

[0047] The rotation of the adjusting disc 27 occurs depending on the loading state of the lower dishware holder 12, which is detected by the sensor device 24. This means that the higher the loading state and thus the weight of the lower dishware holder 12, the greater the spring preload FV (arrow) and the greater the assisting force FU (arrow) when lifting the lower dishware holder 12 from the starting position AP to the end position EP. This means that, regardless of the loading state of the lower dishware holder 12, a user must always apply approximately the same actuating force FB (arrow) to lift the lower dishware holder 12 from the starting position AP to the end position EP. The drive mechanism 19A therefore does not lift the lower dishware holder 12 automatically, but rather supports the user in the lifting process with the assisting force FU (arrow).As previously mentioned, the assist force FU (arrow) depends on the load status of the lower dishware holder 12. The actuating force FB (arrow), however, which the user must apply, is preferably independent of the load status. The actuating force FB (arrow) is preferably constant or consistent.

[0048] Conversely, the drive mechanism 19A also supports the lowering of the lower dishware holder 12 from the end position EP to the starting position AP. Here, too, the support force FU (arrow) depends on the load state of the lower dishware holder 12. This means that when the lower dishware holder 12 is empty or only lightly loaded, the spring preload FV (arrow) is reduced so that the user does not have to press the lower dishware holder 12 downward against the spring element 20. When the load is high, however, the spring preload FV (arrow) is increased so that the lower dishware holder 12 does not move uncontrollably from the end position EP to the starting position AP. Even when lowering the lower dishware holder 12, the actuating force FB (arrow) that the user must apply is therefore independent of the loading state of the lower dishware holder 12. Preferably, the actuating force FB (arrow) is constant or consistent.

[0049] The drive mechanism 19A is thus semi-passive. The lifting device 16 can therefore be referred to as a semi-passive lifting device 16. With the aid of the drive mechanism 19A, it is possible to adapt the support force FU (arrow) to the load of the lower dishware holder 12. Thus, compared to a lifting device that does not have such a spring preload adjustment unit 26, but only a spring element, improved support of the load weight can be achieved. In particular, the actuation force FB (arrow) can be kept within a range that is comfortable for the user. This improves operating comfort.

[0050] The Fig. 7shows a schematic diagram associated with the drive mechanism 19A, in which the force in Newtons is plotted against the lifting height in millimeters. The fully loaded lower dishware holder 12 is marked with a solid line. The empty lower dishware holder 12 is marked with a dashed line, and the required actuating force FB (arrow) is plotted with a dash-dotted line, which must be applied to lift the lower dishware holder 12 from the starting position AP to the end position EP. Arrows with the reference number 32 represent a relaxation of the spring element 20, and arrows with the reference number 33 represent a tensioning of the spring element 20. Depending on whether the lower dishware holder 12 is loaded or unloaded, the spring element 20 is tensioned or relaxed in order to achieve a comfortable actuating force FB (arrow).

[0051] The Fig. 8 to 10show a further embodiment of a drive mechanism 19B for the lifting device 16. The drive mechanism 19B comprises a spring element 34, which is designed as a compression spring. The drive mechanism 19B further comprises a spring preload adjustment unit 35 for adjusting a spring preload FV (arrow) of the spring element 34. The spring preload adjustment unit 35 has an actuating element 36 in the form of a stepper motor. The actuating element 36 in the form of a stepper motor has a threaded spindle 37 and an engagement element 38, into which the threaded spindle 37 engages. The engagement element 38 can be a nut. The engagement element 38 moves along the threaded spindle 37 upon rotation of the threaded spindle 37, as indicated by a double arrow 39. The spring element 34 bears against the engagement element 38. For example, the spring preload adjustment unit 35 is fixedly mounted on the rinsing container 2.

[0052] The drive mechanism 19B further comprises a coupling disc 40 with a lever arm 41. The spring element 34 rests against the lever arm 41. The coupling disc 40 is coupled, for example, to a pivot point of one of the pivot arms 17, 18 of the lifting device 16. A sensor device 42, which has a torque sensor 43, is associated with the coupling disc 40. A braking element 44 can also be associated with the drive mechanism 19B. The braking element 44 can, for example, interact non-positively with the coupling disc 40 and decelerate it. The braking element 44 can, for example, have a plunger 45 actuated by an electromagnet, which interacts with the coupling disc 40.

[0053] Like the spring element 20 of the drive mechanism 19A, the spring element 34 can be continuously moved from an initial state AZ, in which the spring element 34 is minimally preloaded, through any number of intermediate states ZZ to a final state EZ, in which the spring element 34 is maximally preloaded. The spring preload FV (arrow) is therefore greater in the final state EZ than in the initial state AZ. The functionality of the drive mechanism 19B otherwise corresponds to the functionality of the drive mechanism 19A.

[0054] The Fig. 11shows a schematic diagram associated with the drive mechanism 19B, in which the force in Newtons is plotted against the lifting height in millimeters. The maximum spring preload FV (arrow) is plotted with a dotted line. The minimum spring preload FV (arrow) is plotted with a solid line. The maximum force curve and the minimum force curve during lifting are shown with a dash-dotted line and a dashed line, respectively.

[0055] Although the present invention has been described using exemplary embodiments, it can be modified in many ways. Reference symbols used

[0056] 1Household dishwasher 2Wash tub 3Door 4Washing chamber 5Pivot axis 6Loading opening 7Floor 8Ceiling 9Rear wall 10Side wall 11Side wall 12Dishware receptacle; lower dishware receptacle; lower basket 13Dishware receptacle; upper dishware receptacle; upper basket 14Dishware receptacle; cutlery drawer 15Guide device 16Lifting device 17Pivot arm 18Pivot arm 19ADrive mechanism 19BDrive mechanism 20Spring element 21Spring section 22Hanging section 23Hanging section 24Sensor device 25Strain gauge 26Spring preload adjustment unit 27Adjustment disc 28Adjusting element; Stepper motor 29Rotation axis 30Bolt 31Bolt 32Arrow 33Arrow 34Spring element 35Spring preload adjustment unit 36Actuator; stepper motor 37Threaded spindle 38Engaging element 39Double arrow 40Coupling disc 41Lever arm 42Sensor device 43Torque sensor 44Braking element 45Plunger AExtension direction (arrow) APStarting position AZStarting state DDirection of rotation (arrow) EInsertion direction (arrow) EPEnd position EZEnd state FBActuating force (arrow) FUSupport force (arrow) FVSpring preload (arrow) ZZZIntermediate state

Claims

1. Household dishwasher (1) with a lower and upper holder (12; 12, 13) for items to be washed for holding items to be washed and with a lifting device (16) for raising the lower holder (12) for items to be washed from a starting position (AP), in which the lower holder (12) for items to be washed is moved completely out of the dishwasher cavity (2), to an end position (EP), in which the lower holder (12) for items to be washed is moved completely out of the dishwasher cavity (2) with the aid of the lifting device (16) and is raised to around the level of the upper holder (13) for items to be washed, and for lowering the lower holder (12) for items to be washed from the end position (EP) to the starting position (AP), wherein the lifting device (16) comprises a spring element (20, 34) for assisting the raising and lowering of the lower holder (12) for items to be washed with the aid of an assisting force (FU) and a spring bias adjusting unit (26, 35), which tailors the assisting force (FU) to a loading state of the lower holder (12) for items to be washed by adjusting a spring bias (FV) of the spring element (20, 34), characterised in that the spring bias adjusting unit (26, 35) has a setting element (28, 36), embodied as a stepper motor, for adjusting the spring bias (FV) of the spring element (20, 34).

2. Household dishwasher (1) according to claim 1, also comprising a sensor facility (24, 42) for detecting the loading state of the lower holder (12) for items to be washed.

3. Household dishwasher (1) according to claim 2, characterised in that the sensor facility (24) has a strain gauge (25).

4. Household dishwasher (1) according to claim 2, characterised in that the sensor facility (42) has a torque sensor (43).

5. Household dishwasher (1) according to one of the preceding claims, characterised in that the spring bias adjusting unit (26) has an adjusting disk (27), which is coupled to the setting element (28) and the spring element (20), wherein the spring element (20) is coupled to the adjusting disk (27) eccentrically.

6. Household dishwasher (1) according to one of the preceding claims, characterised in that the spring element (20) is a tension spring, wherein the spring bias adjusting unit (26) extends the spring element (20) to increase the spring bias (FV).

7. Household dishwasher (1) according to one of the preceding claims, characterised in that the spring bias adjusting unit (35) has an engagement element (38), which is coupled to the setting element (36) with the aid of a lead screw (37).

8. Household dishwasher (1) according to claim 7, characterised in that the spring element (34) is arranged between the engagement element (38) and a lever arm (41) of a coupling disk (40).

9. Household dishwasher (1) according to claim 7 or 8, characterised in that the spring element (34) is a compression spring, wherein the spring bias adjusting unit (35) compresses the spring element (34) to increase the spring bias (FV).