Patent Publication Number: US-2023160125-A1

Title: Method and control unit for operating a cleaning device in a delicate wash cycle, and cleaning device

Description:
RELATED APPLICATIONS 
     The present disclosure claims priority to and the benefit of PCT Application PCT/EP2021/057277, filed on Mar. 22, 2021, which claims priority to and the benefit of German Application 10 2020 108 764.0, filed on Mar. 30, 2020, the entire contents of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The disclosure relates to a method and to a control unit for operating a cleaning appliance in a delicate wash cycle and to a cleaning appliance. 
     BACKGROUND 
     Cleaning appliances, such as washing machines, are used in abundance in today&#39;s everyday life, both in the private and in the commercial sector. Since the items to be cleaned can react with varying degrees of sensitivity to influences such as temperatures, types of washing, or even cleaning agents, such cleaning appliances have a large number of cleaning programs that can be selected. Such cleaning appliances also generally have a drum in which ribs are arranged for circulating the cleaning liquor and the items to be cleaned. 
     Against this background, EP 2 309 048 A1 describes such a drum having at least one engagement rib for a washing machine. 
     SUMMARY 
     The disclosure provides an improved method and an improved control unit for operating a cleaning appliance in a delicate wash cycle, and an improved cleaning appliance. 
     According to the disclosure, this is achieved by a method and by a control unit for operating a cleaning appliance in a delicate wash cycle and by a cleaning appliance having the features of the main claims. Advantageous embodiments and developments of the disclosure can be found in the subsequent sub-claims. 
     The advantages that can be achieved with the disclosure consist, in addition to an improved washing effect using, for example, gentle programs, in a reduction in the risk of shrinkage of the items to be cleaned. 
     A method for operating a cleaning appliance having a suds container for holding cleaning liquid and a rotatable drum for holding the textiles is therefore presented. The drum is arranged in the suds container. An inside of a drum casing of the drum is also smooth apart from a plurality of nubs. The nubs are shaped in order to cause the cleaning liquid in the drum to execute a wave motion during a cleaning process. Furthermore, the cleaning appliance has a feed unit for feeding the cleaning liquid into the suds container and a drive for causing the drum to execute a rotational motion. The method comprises a step of supplying a feed signal to an interface of the feed unit, the feed signal causing a cleaning liquid to be fed into the suds container until a predetermined target fill level is reached. The target fill level causes the textiles to float inside the drum. Furthermore, the method comprises a step of supplying a motion signal to an interface of the drive when the target fill level is reached, in order to cause the rotational motion of the drum. 
     The method can be executed, for example, in a cleaning appliance, preferably in a washing machine. The cleaning appliance can be shaped so as to wash textiles. The cleaning liquid can be, for example, a mixture of water and a detergent such as is typically used in cleaning appliances. The feed unit may comprise a valve for filling liquid from an external feed line. The drive can comprise a motor that can drive the drum directly or, for example, can drive a belt or a gear. The drum can be referred to as a laundry drum and can be non-ribbed. A non-ribbed drum is used, for example, when the drum does not contain any geometry protruding from the surface where the drum radius is reduced by more than 10%. “Non-ribbed” can be understood to mean that the drum has no ribs on the inside that extend between the drum base and the drum opening, for example parallel to the axis of rotation of the drum. A nub can be understood to mean a hump-like elevation on the inside of the drum. A nub can be pyramid-shaped or tapered. A nub can have a circle or a regular polygon as its base. A nub can also be referred to as a structural element, hump, or mini entraining element. Due to the non-ribbed design of the drum, very sensitive textiles can be cleaned gently. The floating of the textiles can prevent the laundry from falling and thus prevent the wool from shrinking. This can prevent wool fabric from shrinking, for example. Nevertheless, a good washing effect can be achieved. In addition, very long breaks of up to 2-3 minutes can be dispensed with. 
     According to one embodiment, the method can comprise a step of reading in an amount signal via an interface of an amount determination device, wherein the amount signal represents an amount of the textiles. Furthermore, the method can comprise a step of determining the target fill level using the amount signal. The amount determination device can be in the form of a sensor, for example, which is designed to determine the amount of the textiles by weighing the textiles, by using a mass moment of inertia method, or optically. The amount of textiles can indicate a weight or a volume of the textiles. Advantageously, an amount of cleaning liquid required for the cleaning process can be precisely metered as a result. 
     According to one embodiment, the target fill level can cause at least one lower third of the drum to be filled with the cleaning liquid. Advantageously, this allows the textiles to float safely. 
     According to one embodiment, the motion signal can be supplied in the supplying step in order to cause the rotational motion of the drum in a wave washing rhythm that is suitable for causing the wave motion of the cleaning liquid. The rotational motion can take place, for example, in at least one direction, but advantageously also alternately in a further direction opposite to said direction. As a result, the cleaning liquid can be caused as quickly as possible to execute a wave motion. 
     At this time, the wave washing rhythm may be suitable for causing the wave motion with a predetermined frequency of waves of the wave motion. For example, the frequency of the waves can be selected depending on a selected cleaning program or depending on the textiles to be cleaned, so that the waves can be stronger or weaker, for example, and the textiles can therefore flow through them at different strengths. 
     According to one embodiment, the motion signal can be supplied in the step of supplying in order to cause a motion frequency, a drum speed and, additionally or alternatively, a rotational pause value of the rotational motion suitable for implementing the wave washing rhythm. For example, the motion frequency, the drum speed, and additionally or alternatively the rotational pause value of the rotational motion can be changed in order to change the strength and the wave frequency of the cleaning liquid. For example, the motion frequency, the drum speed, and additionally or alternatively the rotational pause value can be adjusted depending on a selected cleaning program. Stored values can be used, which can be selected using a look-up table, for example. 
     In the step of supplying, the motion signal can be supplied in order to cause the rotational motion of the drum in a rocking rhythm with successive rotations of the drum at increasing rotational speeds without a complete revolution of the drum. Advantageously, the textiles are not moved by the drum due to the rotational motion with rapid changes and increasing amplitude, despite the rotating drum. 
     For example, the motion signal can cause the rocking rhythm with a frequency between 0.1 Hz and 0.3 Hz. 
     According to one embodiment, the motion signal can be supplied in the supplying step in order to cause the rotational motion of the drum to be executed for a predetermined period of time in one and the same direction. A period of time is selected that is at least long enough for a horizontal rotational motion of the textiles to be achieved during a cleaning process due to frictional contact of the textiles with a drum base of the drum. The horizontal rotational motion can be understood as meaning a circular motion of the textiles. As a result, a more thorough cleaning of the textiles can advantageously be achieved. The frictional contact is very gentle. 
     According to one embodiment, the period of time can be at least five minutes. This advantageously ensures that the textiles have been mobilized in a desired direction. 
     In the step of supplying, the feed signal can cause the cleaning liquid to be fed until the predetermined target fill level is reached if a program signal indicates that the user has selected the gentle program. In contrast, the feeding can cause the feed of the cleaning liquid until a minimum fill level is reached, which is lower than the target fill level and prevents the textiles from floating inside the drum if the program signal indicates that the user has selected the normal program. In this way, less sensitive textiles can be exposed to greater mechanical stress in the normal program. 
     The approach presented herein also creates a control unit designed to execute, control, or implement the steps of a variant of a method presented herein in corresponding devices. The problem addressed by the disclosure can also be solved quickly and efficiently by this embodiment variant of the disclosure in the form of a control unit. 
     The control unit can be designed to read in input signals and to determine and supply output signals using the input signals. An input signal can represent, for example, a sensor signal that can be read in via an input interface of the control unit. An output signal can represent a control signal or a data signal that can be supplied at an output interface of the control unit. The control unit can be designed to determine the output signals using a processing specification implemented in the hardware or the software. For example, the control unit can for this purpose comprise a logic circuit, an integrated circuit or a software module and can be implemented as a discrete component or comprised by a discrete component. 
     A computer program product or computer program with program code which can be stored on a machine-readable carrier or storage medium, such as a semiconductor memory, a hard disk memory or an optical memory, including non-transitory storage mediums even if such mediums do not necessarily store information permanently, for example random access memory (RAM), is also advantageous. If the program product or program is executed on a computer or a control unit, the program product or program can then be used to execute, implement, and/or control the steps of the method according to one of the embodiments described above. 
     Furthermore, a cleaning appliance for cleaning textiles is presented, which has a suds container for holding cleaning liquid and a rotatable drum for holding the textiles, which is arranged in the suds container. An inside of a drum casing of the drum is smooth apart from a plurality of nubs. The nubs are shaped in order to cause the cleaning liquid in the drum to execute a wave motion during a cleaning process. Furthermore, the cleaning appliance has a feed unit for feeding the cleaning liquid into the suds container, a drive for causing the drum to execute a rotational motion, and a control unit in an aforementioned variant for controlling the feed unit and the drive to operate the cleaning appliance. 
     The cleaning appliance can be implemented as a washing machine, for example, in which a method can be executed in one of the aforementioned variants. The cleaning appliance can be implemented, for example, as a household appliance, but also as a professional device. 
     Furthermore, according to one embodiment, the nubs can be shaped in the form of so-called royal cells. 
     According to one embodiment, the nubs can be shaped as a dome-like enlargement and can protrude into an interior space of the drum. Advantageously, the nubs in this way form a resistance for the cleaning liquid and additionally or alternatively for the textiles in order to set the cleaning liquid and additionally or alternatively the textiles in motion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An embodiment of the disclosure is shown in the drawings in a purely schematic manner and will be described in more detail below. In the drawings: 
         FIG.  1    is a schematic representation of a cleaning appliance according to one embodiment; 
         FIG.  2    is a schematic representation of a cleaning appliance according to one embodiment; 
         FIG.  3    is a schematic representation of a control unit for a cleaning appliance according to one embodiment; 
         FIG.  4    is a perspective view of a drum according to one embodiment of a cleaning appliance; 
         FIG.  5    is a schematic cross-sectional view of a drum according to one embodiment; 
         FIG.  6    is a perspective side view of a drum according to one embodiment; 
         FIG.  7    is a schematic representation of a surface structure of a drum according to one embodiment; and 
         FIG.  8    is a flowchart of a method for operating a cleaning appliance according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
       FIG.  1    is a schematic representation of a cleaning appliance  100  according to one embodiment. The cleaning appliance  100  is designed to clean textiles  102 . The cleaning appliance  100  can be implemented, for example, as a commercially available washing machine, which can be used, for example, for private purposes, but also for commercial purposes. The cleaning appliance  100  has a suds container  104  which is shaped to hold a cleaning liquid  106 . A rotatable drum  108  for holding the textiles  102  is arranged in the suds container  104 . An inside of a drum casing of the drum  108 , as is described in more detail in one of the following drawings, is smooth apart from a plurality of nubs. The nubs are shaped in order to cause the cleaning liquid  106  in the drum  108  to execute a wave motion during a cleaning process. The cleaning appliance  100  also has a feed unit  110  for feeding the cleaning liquid  106  into the suds container  104  and a drive  112  for causing the drum  108  to execute a rotational motion  114 . Furthermore, the cleaning appliance  100  has a control unit  116  which is designed to control the feed unit  110  and the drive  112  for operating the cleaning appliance  100 . In short, the control unit  116  controls, for example, a filling-in process of the cleaning liquid  106  to a target fill level  116  and a motion of the drum  108 . 
     In other words, a concept for a wave washing rhythm for very delicate textiles  102  in a non-ribbed drum  108  for the cleaning appliance  100  is presented. As a result, very sensitive textiles  102 , such as wool or silk, are gently washed achieving a good washing effect. The textiles  102  are passed through by a wave motion of the cleaning liquid  106  without mechanical load, so that an indirect washing takes place via an activation of the free liquor, comparable to a wave pool in which the strength and frequency of the waves can be varied via various adjustment parameters, such as a rocking frequency, rotational speed, and/or break times. 
       FIG.  2    is a schematic lateral representation of a cleaning appliance  100  according to one embodiment. The cleaning appliance  100  can correspond to or be similar to the cleaning appliance  100  described in  FIG.  1   . The cleaning appliance  100  shown herein also has the drum  108  arranged in the suds container  104 , the feed unit  110 , the drive  112 , and the control unit  116 . A drum base  218  is arranged opposite an opening of the drum  108 . 
       FIG.  3    is a schematic representation of a control unit  116  for a cleaning appliance according to one embodiment. The control unit  116  shown herein can be used in a cleaning appliance, as was described in  FIG.  1  or  2   , and is designed to execute a method for operating the cleaning appliance. According to this embodiment, the control unit  116  has a read-in unit  300  and a supply unit  302  for this purpose. 
     The read-in unit  300  is designed to read in an amount signal  304  via an interface of an amount determination device  306 . The amount signal  304  represents an amount of the textiles. According to this embodiment, the read-in unit  300  is also designed to determine a target fill level using the amount signal  304 . 
     The supply unit  302  is designed to supply a feed signal  308  to an interface of the feed unit  110 . In this case, the feed signal  308  causes the cleaning liquid to be fed into the suds container until a predetermined target fill level is reached, which causes the textiles to float inside the drum. Furthermore, the supply unit  302  is designed to supply a motion signal  310  to an interface of the drive  112  when the target fill level is reached, in order to cause the rotational motion of the drum. 
     According to this embodiment, the target fill level causes at least one lower third of the drum to be filled with the cleaning liquid. According to this embodiment, the motion signal  310  optionally causes the rotational motion in a wave washing rhythm that is suitable for causing the wave motion of the cleaning liquid. In summary, this means that the motion signal  310  ultimately causes the wave motion of the cleaning liquid by setting the drum in motion. Further optionally, the wave washing rhythm is adapted to cause the wave motion with a predetermined frequency of waves. According to this embodiment, the motion signal  310  supplied by the supply unit  302  causes a motion frequency, a drum speed, and/or a rotational pause value of the rotational motion suitable for implementing the wave washing rhythm. 
     Furthermore, according to one embodiment, the motion signal  310  causes the rotational motion of the drum in one and the same direction for a predetermined period of time. The period of time is optionally selected to be at least long enough for a horizontal rotational motion of the textiles to be achieved during a cleaning process due to frictional contact of the textiles with a drum base of the drum. The period of time is, for example, at least five minutes. 
     According to one embodiment, the motion signal  310  causes the rotational motion of the drum in a rocking rhythm with successive rotations of the drum at increasing rotational speeds without a complete revolution of the drum taking place. For example, the frequency of the rocking rhythm is between 0.1 Hz and 0.3 Hz. 
     According to one embodiment, the read-in unit  300  is designed to read in a program signal  320  via an interface of an input device  322  of the cleaning appliance. The program signal  320  indicates a user&#39;s program selection. For example, in the event that the program signal  320  indicates a selection of the gentle program, the feed signal  308  is determined in such a way that the cleaning liquid is fed up to the target fill level. If, on the other hand, the program signal  320  indicates a selection of a normal program, the feed signal  308  is determined according to one embodiment such that the cleaning liquid is fed up to a minimum fill level that is so low that the textiles do not float in the drum. In this case, the motion signal  310  is determined in such a way that the rotational motion already described or another suitable rotational motion of the drum is caused. 
     According to one embodiment, the program signal  320  and, additionally or alternatively, the amount signal  304  are used to set the motion frequency, the drum speed, and/or the rotational pause value of the rotational motion. A suitable adjustment specification or, for example, a look-up table can be used. 
     In other words, according to one embodiment, a high water level, which is also referred to as the target fill level, is adjusted at the beginning of a washing program for very delicate laundry. The textiles, which are also referred to as laundry, float up such that there is no direct contact between the textiles and the drum casing. The textiles to be washed are “artificially” suspended, so to speak, which means that the drum casing according to this embodiment does not cause any “hard” mechanical stress. According to this embodiment, a level of the target fill level depends on the amount of laundry detected in advance by means of the amount determination device  306 . The amount of laundry is determined by different actions, such as mass moment of inertia methods or weighing the textiles, for example at the start of the program. The greater the amount of laundry, the higher the target fill level is adjusted. After the cleaning liquid has been fed by means of the feed unit  110 , the cleaning liquid, also referred to as washing suds, is caused to execute a wave motion by the corresponding wave washing rhythm and by the nubs, also referred to as structural elements. For example, the laundry is not moved directly due to the lack of laundry entraining elements, i.e. the ribs, but rather flows through the “wave pool” so that the textiles are massaged. This process ensures an absolutely gentle textile treatment in connection with an improved washing effect. If there is no change of direction during the wave washing rhythm for a longer period of time, the textiles are additionally caused to execute a horizontal rotational motion by a structure of the drum base according to this embodiment. This results in a further mechanical flow. If, for example, the wave washing rhythm is executed like a rocking rhythm, which means rapid changes with increasing amplitude, the laundry is not moved despite the rotating drum. According to an alternative embodiment, these two processes can be varied depending on the program, the amount of laundry, and sensitivity. 
     Due to the wave washing rhythm presented herein and the high water level, an improved washing mechanics is achieved for sensitive loads. This means faster washing and/or an improved washing effect is achieved. According to this embodiment, resources are saved at the same time as a result of the load-dependent target fill level. Due to the variable water level and the wave washing rhythm, optimal washing results are achieved even for small laundry loads of, for example, less than 0.5 kg of wool. 
       FIG.  4    is a schematic representation of a drum  108  according to one embodiment of a cleaning appliance. The drum  108  shown herein can, for example, correspond to or be similar to the drum  108  described in  FIG.  1    or  FIG.  2    and can therefore be used in a cleaning appliance as was described in one of  FIG.  1  or  2   . An inside  400  of a drum casing  401  of drum  108  has a plurality of nubs  402  which are formed in order to cause cleaning liquid in the drum  108  to execute a wave motion during a cleaning process. The inside  400  is smooth with the exception of the nubs  402 . According to this embodiment, the nubs  402  have a hexagonal shape and, according to this embodiment, are surrounded by a honeycomb construction  404 , so that the nubs  402  are shaped in the form of royal cells. According to this embodiment, the nubs  402  are curved in a dome-like manner, so that they protrude into an interior space  406  of the drum  108 . At the highest position of the nubs  402 , the nubs  402  have one or a plurality of through-openings  408 , which are designed to let the cleaning liquid into the interior space  406  of the drum  108 , for example. 
       FIG.  5    is a schematic cross-sectional representation of a drum  108  according to one embodiment. The drum  108  shown herein can, for example, correspond to or be similar to the drum  108  described in  FIG.  4   . According to this embodiment, it can be seen that the nubs  402  on the inside  400  of the drum casing  401  have the enlargement in the direction of the interior space  406 . Apart from that, according to this embodiment, the inside  400  of the drum casing  401  is smooth. According to this embodiment, the nubs  402  are arranged on the drum casing  401  such that two nubs  402  are arranged opposite one another in relation to an axis  500  that runs through the center point  502  of the drum.  FIG.  6    is a perspective side view of a drum  108  according to one embodiment. The drum  108  shown herein can correspond to or be similar to the drum  108  described in  FIG.  4  or  5   , for example. According to this embodiment, adjacent nubs  402  are offset from one another with respect to an axis of rotation of the drum. Furthermore, according to this embodiment, a diameter of at least one drum edge  600  is smaller than a diameter of the drum casing  401 . 
       FIG.  7    is a schematic representation of a surface structure  700  of a drum according to one embodiment. The drum can, for example, correspond to the drum described in one of  FIGS.  4  to  6   . The surface structure  700  can correspond, for example, to an inside or alternatively to an outside of the drum casing. According to this embodiment, two of the nubs  402  are spaced apart from one another on a corresponding longitudinal axis  500 ,  702 ,  704 . According to this embodiment, the longitudinal axes  500 ,  702 ,  704  are aligned parallel to one another. 
       FIG.  8    is a flowchart of a method  800  for operating a cleaning appliance according to one embodiment. The method  800  can be executed in a cleaning appliance, for example, as was described in  FIG.  1   . The method  800  comprises a step  802  of supplying a feed signal to an interface of the feed unit, the feed signal causing a liquid to be fed into the suds container until a predetermined target fill level is reached. The target fill level causes the textiles to float inside the drum. Furthermore, the method  800  comprises a step  804  of supplying a motion signal to an interface of the drive when the target fill level is reached, in order to cause the rotational motion of the drum. According to this embodiment, the method  800  only optionally comprises a step  806  of reading in an amount signal via an interface of an amount determination device before the step  802  of supplying the feed signal, wherein the amount signal represents an amount of the textiles, and also optionally a step  808  of determining the target fill level using the amount signal. Also optionally, the method comprises a step  810  of reading in a program signal that indicates a program selection by the user.