Abstract:
A laundry appliance comprises a drum for receiving articles to be laundered, the drum comprising at least two rotatable drum portions and a drive capable of operating the drum in a plurality of different drum modes. The drum modes include a mode in which the rotatable drum portions are driven so as to cause relative rotation between them. A controller ( 100 ) controls the appliance to perform a plurality of different wash programs, each wash program having an associated drum mode. Each wash program comprises a sequence of stages, with a drum mode being associated with each stage. The drum modes can differ in respect of (a) use (or non-use) of relative rotation between the drum portions (b) the ratio of time that the drum portions rotate compared to the time that they are at rest, and (c) the speed at which the drum portions are rotated. The intensity of a wash program can be varied, inter alia, by varying the length of the wash stage.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a laundry appliance such as a washing machine or washer-dryer and to a control apparatus for such a machine. 
   BACKGROUND OF THE INVENTION 
   Conventional washing machines operate by agitating textile articles within a rotating drum in the presence of water and detergent so that dirt is released from the fibres of the textile articles into the water. The agitation is caused, in the case of front-loading washing machines, by the rotation of the drum about a generally horizontal axis so that the textile articles tumble over one another and rub against each other and against the walls of the drum. However, the rotational speed of the drum is limited because, if the speed is too high, the textile articles will merely be pressed under centrifugal forces against the interior walls of the drum. The articles then rotate with the drum and no agitation with respect to the drum or with respect to other articles is achieved. The amount of agitation which can be applied to the textile articles by front-loading washing machines is therefore limited. This means that, in order to achieve a specific standard of cleanliness, the machine must operate for a minimum period of time. 
   International Patent Application WO99/58753 describes a washing machine in which the drum comprises two rotatable drum portions which are driven in such a way that relative rotation is produced between the drum portions. The relative rotation between the drum portions gives a more vigorous agitation of the articles within the drum, treating them more intensively than they would be in conventional apparatus and consequently dirt is released from the textile articles at a higher rate than in other machines. 
   SUMMARY OF THE INVENTION 
   The present invention seeks to provide an improved laundry apparatus. 
   Accordingly, a first aspect of the invention provides a laundry appliance comprising a drum for receiving articles to be laundered, the drum comprising at least two rotatable drum portions and a drive capable of operating the drum in a plurality of different drum modes, including a drum mode in which the rotatable drum portions are driven so as to cause relative rotation between the adjacent rotatable drum portions, and a controller which is capable of controlling the appliance to perform a plurality of different wash programmes, each wash programme having an associated drum mode. 
   This has the advantage that each wash programme uses a drum mode which is appropriate for the type of load that is to be washed during that wash programme. 
   Preferably, in one of the wash programmes, the controller controls the drive to operate in a drum mode in which the drum portions are not rotated relative to one another at any point during the wash programme. This has the advantage that the drum can accommodate a load of the type which would not normally be suited to this type of appliance, such as a duvet. 
   The portions of the drum can be rotated in opposite directions at the same or different speeds. Alternatively, each of the portions of the drum can be rotated at a different speed in the same direction. 
   Preferably the appliance has a control panel for allowing a user to select an intensity for the chosen wash programme, such as when clothes are more heavily or more lightly soiled than normal. The controller is arranged to vary, in use, the intensity of the wash programme in accordance with the selection made by a user. The intensity of the wash programme can be varied by varying the length of the wash portion of the wash programme, varying the ratio of time during which the drum portions are rotated relative to one another compared to the time during which the drum portions are not rotated or varying the speed of relative rotation between the drum portions. The latter two options have the advantage of allowing the wash intensity to be varied without increasing the length of the wash programme. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A further aspect of the invention provides a control apparatus for the laundry appliance. 
     Embodiments of the invention will now be described with reference to the accompanying drawings, in which: 
       FIG. 1  is a cross-sectional view of a washing machine embodying the present invention; 
       FIG. 2  shows a control system for the machine of  FIG. 1 ; 
       FIG. 3  shows one form of control panel for the, machine of  FIG. 1 ; 
       FIGS. 4A-4C  show one drum mode performed by the machine of  FIG. 1 ; 
       FIGS. 5A-5C  show another drum mode performed by the machine of  FIG. 1 ; 
       FIGS. 6 and 7  are tables which give details of the wash programmes performed by the machine of FIG.  1  and  FIG. 8  is a key for these tables. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a washing machine  10  which includes an outer casing  12  in which a stationary tub  40  is located. A drum  50  is mounted inside the tub  40  so as to be rotatable about an axis  85 . The tub  40  is watertight except for an inlet  21  and outlet  22 . The washing machine  10  includes a soap tray  20  capable of receiving detergent in a known manner. At least one water inlet  23  communicates with the soap tray  20  and is provided with suitable means for connection to a water supply within the environment in which the washing machine  10  is to be used. A conduit  21  is provided between the soap tray  20  and the tub  40  so as to allow water introduced via the inlet  23  to enter the tub  40 . The tub  40  has a sump  26  located beneath the drum  50 . A drainage pipe  28  communicates with the sump  26  and leads to a water outlet  30  via which water can be discharged from the washing machine  10 . A pump  42  is provided to allow water to be pumped from the sump  26  to the water outlet  30  at appropriate stages of the washing cycle carried out by the washing machine  10 . 
   The drum  50  is rotatably mounted about the axis  85  by way of a shaft  80 . The shaft  80  is mounted in a known manner, allowing the tub  40  to remain stationary whilst the drum  50  is rotatable with the shaft  80 . The shaft  80  is rotatably driven by a motor (not shown) mounted within the outer casing  12  of the washing machine  10 . A door  66  is located in the front panel  12   a  of the outer casing  12  to allow access to the interior of the drum  50 . It is via the door  66  that a wash load can be deposited within the drum  50  before a wash cycle commences and removed from the drum  50  at the end of the wash cycle. 
   Drum  50  comprises two portions  60 ,  70  which are mounted such that they can be rotated with respect to one another. A drum of this type is described more fully in International Patent Application WO99/58753. Typically the drum portions  60 ,  70  are rotated in opposite directions to one another, i.e. one portion clockwise, one counter-clockwise, but they can also be rotated together in the same direction. The drum  50  is mounted in a cantilever fashion on the wall of the tub  40  remote from the door  66 . The first outer rotatable portion  60 , is supported on a hollow cylindrical shaft  81 . An angular contact bearing  82  is located between the rear wall of the tub  40  and the hollow cylindrical shaft  81 . The outer rotatable portion  60  is dimensioned so as to substantially fill the interior of the tub  40 . More specifically, the outer rotatable portion  60  has a generally circular rear wall  63  extending from the hollow cylindrical shaft  81  towards the cylindrical wall of the tub  40 , a generally cylindrical wall  61  extending generally parallel to the cylindrical walls of the tub  40  from the rear wall  63  towards the front wall of the tub  40 , and a generally annular front face  64  extending from the cylindrical wall  61  towards the door  66 . Sufficient clearance is allowed between the walls  61 ,  63 ,  64  of the outer rotatable portion  60  and the tub  40  to prevent the outer rotatable portion  60  from coming into contact with the tub  40  when the drum  50  is made to spin. 
   An inner cylindrical wall  62  is also provided on the interior of the cylindrical wall  61  of the outer rotatable portion  60 . The inner cylindrical wall  62  extends from a point which is substantially midway between the rear wall  63  and the front face  64  to the front face  565 . The space between the interior cylindrical wall  62  and the cylindrical wall  61  is hollow but, if desired, could be filled with a strengthening material. In this event, the strengthening material must be lightweight. The provision of parallel cylindrical walls  61 ,  62  in the portion of the outer rotatable portion  60  closest to the front face  64  provides strength to the whole of the outer rotatable portion  60  whilst reducing the internal diameter of the outer rotatable portion  60  in this region. 
   The inner rotatable portion  70  is supported on a central shaft  80 , which in turn, is supported by deep groove bearings  83  located between the central shaft  80  and the hollow cylindrical shaft  81 . The inner rotatable portion  70  essentially comprises a generally circular rear wall  71  extending from the central shaft  80  towards the cylindrical wall of the tub  40 , and a cylindrical wall  74  extending from the periphery of the rear wall  71  towards the front wall of the tub  40 . The diameter of the cylindrical wall  74  of the inner rotatable portion  70  is substantially the same as the diameter of the inner cylindrical wall  62  of the outer rotatable portion  60 . The cylindrical wall  74  of the inner rotatable portion  70  is dimensioned so that its distal end approaches the end of the cylindrical wall  62  closest to it. It is advantageous to keep the gap between these two cylindrical walls  62 ,  74  as small as possible. An annular sealing ring  76  is located on the cylindrical wall  61  of the outer cylindrical portion  60  immediately adjacent to the end of the inner cylindrical wall  62  closest to the inner cylindrical portion  70  so as to provide support for the distal end of the cylindrical wall  76  thereof. 
     FIG. 2  shows part of the control system of the machine  10 . A controller  100  operates according to a control program stored on a non-volatile memory  105 . The controller  100  is preferably implemented in the form of a microcontroller but other ways of implementing the controller, such as an implementation entirely in hardware, will be apparent to the reader and are intended to fall within the scope of this invention. 
   An interface  110  interfaces the controller  100  to other parts of the machine  10 . Sensors placed on the machine return signals to the interface  110 . The sensors include a water temperature sensor for monitoring temperature of the wash water in the sump of the machine  10  and a motor speed sensor. The interface  110  also outputs signals to control operation of the display  220  to display text messages and signals to control the illumination of indicator lamps  215 ,  265  on the control panel  120 . Interface  110  also receives inputs from each of the control buttons  210 ,  230 ,  240 ,  250 ,  260  on the control panel  120  which allows the controller  100  to determine what button a user has pressed. The interface  110  also outputs a set of control signals  140  to control the operating state of various parts of the machine, such as the door lock, water inlet valves, and the motor M. In a well-known manner, the control software  105  controls operation of the machine according to the inputs it receives and issues outputs  140  for controlling various parts of the machine. 
   The speed of motor M is controlled on the basis of the monitored supply voltage and motor speed inputs to the interface and an output signal  145  to motor drive  130 . Control signal  145  controls the firing angle of the triac (or other power switching device) in the motor drive circuit  130 . Another output signal  144  controls the direction of rotation of the motor M and a further output signal  146  controls the state of the gearbox. The state of the gearbox determines whether the drum portions  60 ,  70  are rotated in unison or whether they are rotated relative to one another. Motor M can be used to drive both drum portions  60 ,  70  or two separate motors may be provided, one motor being used to drive each of the drum portions  60 ,  70 . 
     FIG. 3  shows one embodiment of control panel  120  in more detail. It will be appreciated that the control panel can vary from the one shown here. For example, the control panel  120  may provide a different range of options, the type of control may vary e.g. push button, touch-sensitive control, switch, rotatable control knob or slider. Also, the range and type of visual indicators can vary, e.g. the indicators can include LEDs, an LCD or electroluminescent display. 
   The control panel of  FIG. 3  includes an on/off button  201  to turn the mains power supply to the machine on/off; a set of control buttons  210  and associated indicators  215  for selecting the wash programme (cotton, synthetics, wool, delicates etc.); a control button  230  and an associated set of indicators for selecting the wash temperature (20-85° C.); a control button  240  and an associated set of indicators for selecting spin speed (0-1600 rpm); a control button  250  and an associated set of indicators for selecting wash intensity (light, normal, heavy); a set of control buttons  260  and an associated set of indicators  265  for selecting special features (minimum crease, pre-wash, extra rinse etc.); a plurality of memory buttons  270 ,  271 ,  272  for selecting a combination of stored settings; a start button  280  for starting the machine according to the settings programme by a user, and a cancel button  282 . A further indicator  283  indicates when the door  30  of the machine is locked and indicator  284  indicates when the child lock mode is active. 
   An LCD display  220  displays text messages at various stages during operation of the machine to help a user select programme settings and to indicate the progress of the machine through the wash cycle. 
   There are two basic types of drum mode: a counter-rotating mode in which the drum portions  60 ,  70  are rotated relative to one another and a normal mode in which the drum portions  60 ,  70  are rotated in unison in the same direction in a conventional manner. 
   The following table gives details of five drum modes. Each drum mode comprises a repeated sequence of four steps. For example, the ‘Counter Rotation’ operation performs: a first step which counter-rotates the drum portions  60 ,  70  with respect to one another for  13   s ; a second step which rests for  6   s  with no drum action; a third step which counter-rotates the drum portions  60 ,  70  with respect to one another for  13   s  in the opposite direction to that used in action  1 ; and a fourth step which rests for  6   s  with no drum action. Clearly, any of the parameters of the drum operations defined here could be varied as appropriate. 
   
     
       
             
             
             
             
           
             
             
             
             
           
         
             
                 
             
             
               Drum Mode 
               Step no. 
               Duration (s) 
               Drum speed (rpm) 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
               Counter Rotation 
               1 
               13 
               52 
             
             
               (CR) 
               2 
               6 
               0 
             
             
                 
               3 
               13 
               −52 
             
             
                 
               4 
               6 
               0 
             
             
               Counter Rotation 
               1 
               10 
               52 
             
             
               Normal 
               2 
               32 
               0 
             
             
               (CRN) 
               3 
               10 
               −52 
             
             
                 
               4 
               32 
               0 
             
             
               Normal Action 
               1 
               11 
               52 
             
             
               (NA) 
               2 
               5 
               0 
             
             
                 
               3 
               11 
               −52 
             
             
                 
               4 
               5 
               0 
             
             
               Gentle Action 
               1 
               6 
               52 
             
             
               (GA) 
               2 
               12 
               0 
             
             
                 
               3 
               6 
               −52 
             
             
                 
               4 
               12 
               0 
             
             
               Super Gentle Action 
               1 
               6 
               52 
             
             
               (SGA) 
               2 
               27 
               0 
             
             
                 
               3 
               6 
               −52 
             
             
                 
               4 
               27 
               0 
             
             
                 
             
           
        
       
     
   
     FIGS. 4A-4C  illustrate steps numbers  1 - 3  for the counter-rotating drum modes. The drum portions  50 ,  60  firstly rotate in opposite directions (FIG.  4 A), then rest (FIG.  4 B), then rotate in opposite directions ( FIG. 4C ) with each drum portion  60 ,  70  rotating in a different direction to that in FIG.  4 A and finally rest (not shown.)  FIGS. 5A-5C  illustrate actions for the normal drum modes. The drum portions  60 ,  70  firstly rotate in unison in the same direction (FIG.  5 A), then rest (FIG.  5 B), then rotate in unison ( FIG. 5C ) in the opposite direction to that in FIG.  5 A and finally rest (not shown.) 
   In the above table, the Counter Rotations (CR) and Counter Rotation Normal (CRN) modes differ in the ratio of time when the drums are rotating (and therefore agitating the load) and when the drums are at rest. In the CR mode the drums are rotating for roughly twice the time that they are at rest whereas in the CRN mode the drums are at rest for roughly three times the time that they are rotating. Similarly, with the normal modes, the modes differ in the ratio of time when the drums are rotating (and therefore agitating the load) and when the drums are at rest. While the modes detailed above all operate at the same drum speed of 52 rpm it is possible to vary the drum speed between modes to vary the amount of agitation that these modes provide. 
     FIGS. 6 and 7  are tables which give full details of a set of wash programmes performed by the machine  10  and  FIG. 8  is a key for these tables. A complete wash cycle comprises the following stages: prewash (if the user has selected this), main wash, rinse, final rinse and final spin. Each of these stages comprises a number of steps. During each step the machine operates with a combination of an amount of water, a water temperature and a drum mode  400  detailed in the tables. As is well-known with conventional wash programmes, the water temperature that is used during the wash programme varies according to the type of fabric being washed, with robust fabrics such as cotton being washed at a higher temperature than delicates. 
   During the stages of the wash cycle, and particularly during the main wash (see “Main Wash” step no.  3 ,  FIG. 6 ) the machine operates with a drum mode which is dependent on the wash programme. The most robust fabric types such as cottons, synthetics and dedicates use the CR drum mode (long burst of counter-rotation followed by a short rest); wool and care+ use the CRN drum mode (short burst of counter-rotation followed by a long rest) and the duvet programme does not use counter-rotation at all, since the load comprises one large article which is expected to fill the drum, conditions which are not suited to the use of a counter-rotating drum mode. The length of the wash step (see “Main Wash” step no.  3 ,  FIG. 6 ) varies according to the amount of soiling of the articles in the wash load: 4 minutes for light soiling, 6 minutes for normal soiling and 10 minutes for heavy soiling. A user selects the intensity of the wash via control  250  on the control panel  120 . However, as an alternative to varying the length of time for the wash step, the controller can vary the amount of agitation by varying the drum mode. Increased agitation can be provided by using a drum mode which rotates the drum portions  60 ,  70  at a higher speed relative to one another or with a longer ratio of rotation time to rest time. 
   Variations to the described embodiments are intended to fall within the scope of the present invention. While five drum modes are described here, it is possible to provide more modes which vary in the amount of agitation they apply to the wash load. The modes can vary in the ratio of rotating time to rest time and/or speed of rotation. The drum  50  can comprise more than just the two rotatable portions  60 ,  70 . Three or more separately rotatable portions can be provided, all lying alongside one another along the axis of rotation.