Patent Publication Number: US-11035067-B2

Title: Laundry machine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 15/636,092, filed on Jun. 28, 2017, which claims the benefit of an earlier filing date and right of priority to Korean Patent Application No. 10-2016-0181642, filed on Dec. 28, 2016. The disclosures of the prior applications are incorporated by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure generally relates to a laundry machine. 
     BACKGROUND 
     Generally, examples of laundry machines include washers for washing laundry, dryers for drying clothes, and laundry machines that perform both washing and drying of clothes. 
     Typically, a laundry machine implements two laundry treating devices, such as a tub and a drum, that have different volumes. Such laundry machines are typically referred to as twin laundry machines. Various types of clothes and laundry may be loaded and selectively washed, dried, and/or treated in such twin laundry machines, and such twin laundry machines sometimes include two different devices according to the types or amount of the laundry. 
     SUMMARY 
     In one aspect, a laundry machine may include a first washing unit including a first tub, a first drum mounted inside the first tub, and a first drive unit configured to drive a rotation of the first drum around a first rotational shaft inside the first tub. The laundry machine may also include a second washing unit including a second tub, a second drum mounted inside the second tub, and a second drive unit configured to drive a rotation of the second drum around a second rotational shaft inside the second tub. The second washing unit may be arranged above the first washing unit and may be configured with a second laundry treating capacity that is smaller than a first laundry treating capacity of the first washing unit. A diameter of the second drum may be larger than a height of the second drum. The first rotational shaft of the first washing unit may not be not parallel to the second rotational shaft of the second washing unit. The second drive unit may include a motor connected to the second rotational shaft of the second drum in an outer lower portion of the second tub. A first recess of the second tub may be defined to project downward from a rear portion of a lower surface of the second tub and is configured to heat wash water in the second tub. A metal plate member may be provided on an outside of the lower surface of the second tub and may be configured to reinforce the second tub, the metal plate member configured to partially extend towards the rear portion of the lower surface of the second tub and to expose a bottom surface of the first recess of the second tub. 
     In some implementations, the second tub may be made of plastic. 
     In some implementations, the metal plate member may be affixed to the lower surface of the second tub. 
     In some implementations, the metal plate member may be affixed directly to the lower surface of the second tub. 
     In some implementations, a first portion of the metal plate member may be integrally formed in the lower surface of the second tub. 
     In some implementations, the first portion of the metal plate member that is integrally formed in the lower surface of the second tub may be a center portion of the metal plate member that is injection-molded into the lower surface of the second tub. 
     In some implementations, the metal plate member may be configured to partially extend towards the rear portion of the lower surface of the second tub and to expose the bottom surface of the first recess of the second tub by extending further towards a front of the second tub rather than a rear of the second tub where the first recess is provided. 
     In some implementations, the laundry machine may further include a cabinet defining an exterior of the laundry machine. The first washing unit and the second washing unit may be provided in the cabinet. 
     In some implementations, the first recess may be a first portion of an interior space of the second tub that projects further in a downward direction as compared to a second portion of the interior space of the second tub. 
     In some implementations, the first recess may be formed in an outer radial portion of the second tub in a radial direction of the motor of the second drive unit. 
     In some implementations, relative to a center of the second tub, a first area of the lower surface of the second tub that is covered by the metal plate member that extends from the center of the second tub to a front of the second tub may be larger than a second area of the lower surface of the second tub that is covered by the metal plate member that extends from the center of the second tub to a rear of the second tub. 
     In some implementations, the metal plate member may be provided between the lower surface of the second tub and the motor of the second drive unit. 
     In some implementations, a first portion of the metal plate member may be provided to surround the motor of the second drive unit, and the metal plate member may be configured to transfer heat from the first portion surrounding the motor downward to an outside of the laundry machine. 
     In some implementations, a first portion of a drying duct that is provided in the first washing unit may be provided in a space formed between a lower portion of the second washing unit and an upper portion of the first washing unit, and the metal plate member may be configured to vertically overlay at least a portion of the drying duct. 
     In some implementations, the metal plate member may include a stepped portion that is molded to the lower surface of the second tub. 
     In some implementations, the motor of the second drive unit may include a stator directly mounted to a lower back surface of the second tub; and a rotor provided to surround the stator. A bottom surface of the first recess may be located at a height that is lower than a lowermost portion of the motor of the second drive unit. 
     In some implementations, the motor of the second drive unit may include: a stator mounted to a lower back surface of the second tub via the metal plate member; and a rotor provided to surround the stator. The bottom surface of the first recess may be located at a height that is lower than a lowermost portion of the motor of the second drive unit. 
     In some implementations, the motor of the second drive unit may include a stator; and a rotor provided to surround the stator. The metal plate member may include an inclined portion formed to surround the rotor, the inclined portion formed over the rotor and inclined downward in an outward radial direction. 
     In some implementations, the first rotational shaft of the first washing unit may be perpendicular to the second rotational shaft of the second washing unit. 
     In some implementations, the first recess of the second tub may be configured to heat the wash water in the second tub by heating at least one surface of the second tub that defines the first recess. 
     Further scope of applicability of the present disclosure will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples are given by way of illustration only, and various changes and modifications within the spirit and scope of the disclosure may be made. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 and 2  are diagrams illustrating examples of cross-sectional views of a laundry machine in accordance with the present disclosure; 
         FIG. 3  is a diagram illustrating another example of a laundry machine; 
         FIG. 4  is a diagram illustrating another example of a laundry machine; and 
         FIG. 5  is a diagram illustrating a further example of a laundry machine. 
     
    
    
     DETAILED DESCRIPTION 
     Implementations disclosed herein provide a laundry machine, which may be referred to as a twin laundry machine, that includes two different laundry treating devices. The two laundry treating devices may be configured to facilitate loading and unloading of laundry. For example, in some implementations, the laundry machine may be configured with reduced overall height in providing the two different treating devices, thus improving convenience of using both devices. 
     Implementations of the present disclosure may also provide a laundry machine that reduces the transfer of vibrations, interference, and heat between the two different treating devices. Thus, in implementations in which the two laundry treating devices are provided in a single cabinet, implementations of the present disclosure may enable a laundry machine with improved reliability and durability in a compact overall size. 
     In some implementations, the laundry machine may include first and second washing units. The first washing unit includes a first tub, a first drum, and a first drive unit for driving the first drum, and the second washing unit includes a second tub, a second drum, and a second drive unit for driving the second drum. The second washing unit may be arranged on a top of the first washing unit and may have a smaller laundry treating capacity than the first washing unit. The second drum may have a diameter larger than its height, and may also have a shaft that is angled (e.g., perpendicular) relative to a shaft of the first drum. The second drive unit may include a motor connected to the shaft of the second drum in an outer lower portion of the second tub. The motor may include a stator mounted to the lower back surface of the tub; and a rotor surrounding the stator. 
     A plate member may be provided between the motor and an outer surface of the second tub. This plate member may be configured to shield off and reduce heat that is generated in the motor from being transferred to the second tub. The plate member may thus be arranged outside the second tub and configured to reinforce and protect the second tub. 
     The plate member may be fixed to an outer surface of the second tub. For example, the plate member may be attached to the outer surface of the second tub in a close proximity. In some scenarios, a predetermined portion of the plate member may be inserted in the second tub when injection-molding the second tub, and may be integrally formed with the second tub. The plate member may be metallic, in some implementations. 
     The second washing unit may be arranged on a top of the first washing unit. In some implementations, the laundry treating capacity of the first washing unit may be larger than that of the second washing unit. 
     The cabinet may be a single cabinet defining an exterior of the laundry machine, and the first washing unit and the second washing unit may be provided in the single cabinet. As such, the laundry machine may include two washing units which are mounted in the single cabinet. 
     A predetermined portion of a drying duct may be provided in between a bottom surface of the second washing unit and a top surface of the first washing unit, and the metal plate member may be vertically overlapped with the drying duct. 
     The plate member may be provided in a lower back surface of the second tub. In some scenarios, a predetermined portion of the plate member may be provided to surround the motor and the heat which rises in the motor may be guided downward to a radiation direction via the plate member to be exhausted outside. 
     A recess may be formed in the second tub and may be configured to heat wash water. For example, the recess may be formed in an outer portion of the second tub in a radial direction of the motor. The plate member may be configured so as not to cover the recess. For example, the recess may be provided in a rear portion of the second tub, and the plate member may be configured to extend further towards a front portion of the second tub, and not extend fully to the rear portion where the recess is located. 
     The temperature of the drying duct may be higher in a front portion than in a rear portion, so that the heat exchange between the drying duct and the second tub may be reduced by the plate member. 
     The plate member may include a stepped portion to be molded to the lower back surface of the second tub, so as to improve the strength and securing strength. In some implementations, the second tub may be made of plastic and the plate member may be made of metal. For example, the plate member may be formed by aluminum die casting. 
     A heat radiation shut-off film may be provided in a surface of the plate member so as to prevent the radiation heat from being absorbed in the plate member. Accordingly, the more effective heat radiation function can be expected. 
     Implementations of the present disclosure also provide a laundry machine including a first washing unit including a first tub, a first drum and a first drive unit for driving the first drum; and a second washing unit including a second tub, a second drum and a second drive unit for driving the second drum, the second washing unit arranged on a top of the first washing unit and having a smaller laundry treating capacity than the first washing unit, the laundry machine wherein the second drum has a diameter which is larger than the height and a shaft which intersects a shaft of the first drum, and the second drive unit includes a motor connected to the shaft of the second drum in an outer lower portion of the second tub, and a recess is formed from a lower outer surface of the second tub to an outer portion in a radial direction of the motor to be connected to a drainage pump and the recess is more projected downward than the other portion, and a plate member if provided between the motor and the lower outer surface of the tub and guiding the heat rising in the motor in a heat radiation direction downward to be exhausted outside. 
     The plate member may include a metal plate secured to the lower outer surface of the second tub. The plate member may include an inclined portion formed to surround the rotor, over the rotor, and inclined downward in an outer portion in a radial direction. 
     The lower outer surface of the recess may be vertically located lower than a lower outer surface of the motor. The plate member may be provided in the lower outer surface of the second tub, and may be configured so as not to cover the lower outer surface of the second tub where the recess is located. For example, the recess may be located in a rear portion of the second tub, and the plate member may extend toward a front portion of the second tub, opposite from the recess, and not extend fully to the rear portion of the second tub where the recess is located. 
     Implementations of the present disclosure also provide a laundry machine including a cabinet including a first opening provided in a front surface and a second opening provided in an upper surface; a first tub provided in the cabinet and defining a predetermined space for storing water, in communication with the first opening; a first drum rotatably mounted in the first tub and defining a predetermined space for storing clothes, in communication with the first opening; a second tub provided in the cabinet, over the first tub, and defining a predetermined space for storing clothes, in communication with the second opening; a second drum rotatably mounted in the second tub and defining a predetermined space for storing clothes, in communication with the second opening; and a hot air supply unit provided in the cabinet and supplying heated air to the first tub or the second tub, located in a space formed between a bottom surface of the second tub and the first tub. 
     Implementations of the present disclosure also provide a laundry machine including a first washing unit including a first tub, a first drum and a first drive unit for driving the first drum; and a second washing unit including a second tub, a second drum and a second drive unit for driving the second drum, the second washing unit arranged on a top of the first washing unit and having a smaller laundry treating capacity than the first washing unit, wherein the second drum has a diameter which is larger than the height and a shaft which intersects a shaft of the first drum, and the second drive unit includes a motor connected to the shaft of the second drum in an outer lower portion of the second tub, and a recess projected downward is formed in a lower back surface of the second tub to heat wash water, and a metal plate member is provided in a rear surface of the second tub to reinforce the strength of the second tub, except a rear surface of the recess. 
     The second tub may be made of plastic. The metal plate member may be fixed to a rear surface of the second tub. The metal plate member may be attached to the rear surface of the second tub closely. A predetermined portion of the metal plate member may be inserted in the second tub when injection-molding the second tub and integrally formed with the second tub. 
     The cabinet may be a single cabinet defining an exterior of the laundry machine, and the first washing unit and the second washing unit may be provided in the single cabinet. 
     The recess may be formed in an outer portion in a radial direction of the motor. The area of the second tub covered by the metal plate member may be larger in the opposite portion to the recess than the portion near the recess with respect to the center of the second tub. The metal plate member may be provided between the rear surface of the second tub and the motor. A predetermined portion of the metal plate member may be provided to surround the motor and the heat which rises in the motor is guided downward to a radiation direction via the metal plate member to be exhausted outside. 
     A predetermined portion of a drying duct provided in the first washing unit may be provided in a space formed between a lower portion of the second washing unit and an upper portion of the first washing unit, and the metal plate member may be vertically overlapped with the drying duct. 
     The metal plate member may include a stepped portion to be molded to the lower back surface of the second tub. 
     The motor may include a stator directly mounted to a lower back surface of the tub; and a rotor provided to surround the stator, and the lowermost portion of the recess is located lower than the lowermost portion of the motor. In some implementations, the motor may include a stator mounted to a lower back surface of the tub via the metal plate member; and a rotor provided to surround the stator, and the lowermost portion of the recess may be located lower than the lowermost portion of the motor. 
     The motor may include a stator; and a rotor provided to surround the stator, and the metal plate member includes an inclined portion formed to surround the rotor, over the rotor, and inclined downward in an outer portion in a radial direction. 
     Some examples of implementations will be described below in more detail with reference to the accompanying drawings. 
     Referring to  FIG. 1 , a laundry machine  100  includes a cabinet  1 . The cabinet  1  includes a first laundry treating device, which includes a first tub  2  and a first drum  3 , defining a predetermined space in which washing of drying for clothes can be performed. The cabinet  1  also includes a second laundry treating device, which includes a second tub  4  and a second drum  6 , defining a predetermined space in which washing or drying for clothes can be performed. The second laundry treating device is arranged above the first laundry treating device. For example, the first laundry treating device may be a first washing unit and the second laundry treating device may be a second washing unit. 
     The cabinet  1  defines an exterior of the laundry machine and includes a bottom surface supported by the ground; an upper surface  12  arranged over the bottom surface; and a lateral surface connecting the upper surface and the bottom surface with each other. The lateral surface may consist of a front surface  11  arranged in a front of the laundry machine and a rear surface arranged in a backside of the laundry machine. 
     A first opening  13  is provided in the front surface  11  to communicate with the first laundry treating device (first tub  2  and first drum  3 ) and a second opening  14  is provided in the upper surface  12  to communicate with the second laundry treating device (second tub  4  and second drum  6 ). An external air inlet hole  19  is provided in the rear surface of the cabinet  1  to draw external air into the cabinet  1 . 
     The first opening  13  is open or closed by a first door  15  rotatably coupled to the front surface  11  and the second opening  14  is open or closed by a second door  16  rotatably coupled to the upper surface  12 . 
     In some implementations, the first door  15  may be configured to open and close the first opening  13  and a first tub opening  23  of the first laundry treating device. The second door  16  may be provided to open and close only the second opening  14 . 
     The first laundry treating device includes a first tub  2  provided in the cabinet  1  and in communication with the first opening  13 ; and a first drum  3  rotatably mounted in the first tub  2  and providing a predetermined space for storing clothes or laundry. 
     The first tub  2  may be formed in any suitable shape that holds water.  FIG. 1  illustrates the first tub  2  which is formed in a cylindrical shape as one example. 
     In this instance, the first tub  2  includes a first tub body  21  formed in a hollow cylinder shape; and a first tub opening  23  penetrating a front surface of the first tub body and in communication with the first opening  13 . 
     The first tub body  21  is fixed in the cabinet  1  by a first tub support unit  251 ,  253  and  255 , which will be described in detail later. 
     The first opening  13  and the first tub opening  23  are connected by a gasket  231 . The gasket  231  may be formed of an elastic material such as rubber to prevent the leakage of water from the first tub body  21  and the transferring of vibration from the first tub body  21  to the cabinet  1 . 
     The first drum  3  may be provided in any suitable shape configured to rotate within the first tub body  21 .  FIG. 1  illustrates the first drum formed in a cylindrical shape as one example. 
     In this instance, the first drum  3  may include a first drum body  31  formed in a hollow cylindrical shape; a first drum opening  33  penetrating a front surface of the first drum body and in communication with the first tub opening  23 ; and a plurality of penetrating holes  35  penetrating the first drum body  31  to make an internal space of the first drum body communicate with an internal space of the first tub body. 
     The first drum opening  33  communicates with the first opening  13  via the first tub opening  23 . When the first door  15  opens the first opening  13 , the user is able to load clothes into the first drum body  31  or unload the clothes held in the first drum body  31  via the first opening  13 , the first tub opening  23  and the first drum opening  33 . 
     The first drum body  31  is rotatable by a first drive unit. As one example,  FIG. 1  illustrates the first drive unit including a first stator  371  fixed to a rear surface of the first tub body  21  and forming a rotating field; a first rotor  373  rotatable by the rotating field; and a first shaft  375  connecting the first drum body  31  to the first rotor  373  through the rear surface of the first tub body. 
     The first shaft  375  may be provided in parallel with the bottom surface of the cabinet (or to form an angle smaller than a threshold angle with respect to the bottom surface of the cabinet) and to form zero or more degree angle with respect to the bottom surface of the cabinet  1 . 
     In the latter case, the first shaft  375  has to be provided to have a smaller angle than 90 degrees with respect to the bottom surface of the cabinet. The second laundry treating device (second tub  4  and second drum  6 ) is located on the top of the first laundry treating device (first tub  2  and first drum  3 ) and the first drum opening  33  is located in the front surface of the first drum body  31  so that the tilt angle of the first shaft  375  has to be 90 degrees or more with respect to the bottom of the cabinet and that the user can unload the clothes held in the first drum body  31  out of the cabinet. 
     The first laundry treating device (first tub  2  and first drum  3 ) having the structure mentioned above may receive water via a first water supply unit and may drain the water out of the cabinet via a first drainage unit. The first water supply unit may include a first water supply pipe  211  connecting the first tub body  21  to an external water supply source arranged outside the cabinet; and a first valve  213  for opening or closing the first water supply pipe  211  according to a control signal of at least one processor, such as a controller. 
     In some implementations, the first drainage unit may include a first drainage pipe  215  for guiding the water held in the first tub body toward the outside of the cabinet  1 ; and a first pump  217  for moving the water held in the first tub body along the first drainage pipe  215 . 
     The first drainage pipe  215  may be provided to pass a higher point than the highest water level set in the first tub body  21 . In some scenarios, this configuration may facilitate the water storing in the first tub body  21 , even without an auxiliary valve for opening and closing the first drainage pipe. 
     The second laundry treating device includes a second tub  4  provided beyond the first tub body  21  and defining a predetermined space for storing water, in communication with the second opening  14 ; and a second drum  6  rotatably mounted in the second tub  4  and defining a predetermined space for storing clothes. 
     The second tub  4  may be formed in any suitable shape configured to provide a space for storing water and  FIG. 1  illustrates the second tub  4  formed in a cylindrical shape as one example. 
     In this instance, the second tub  4  may include a second tub body  41  provided in a hollow cylinder shape and located beyond the first tub body  21 ; and a second tub opening  43  penetrating an upper surface of the second tub body  41  and in communication with the second opening  14 . 
     The second tub body  41  is fixed in the cabinet  1  by a second tub supporting unit  47 . The implementation of the laundry machine may include at least three second tub supporting unit  47  which are spaced a distance apart from each other along a circumferential surface of the second tub body  41 . 
     The second tub supporting unit may include a support bar  475  having one end rotatably coupled to the cabinet  1  and the other end rotatably coupled to the second tub body  41 . 
     More specifically, the second tub supporting unit  47  may include a first bracket  471  provided in the cabinet  1  and rotatably supporting an upper end of the support bar; and a second bracket  473  provided in the second tub body  41  and rotatably supported to a lower end of the support bar  475 . In this instance, a first coupling portion  477  is provided in the upper end of the support bar  475  to be rotatably supported to the first bracket  471 . A second coupling portion  479  is provided in a lower end of the support bar  475  to rotatably support the second bracket  473 .  FIG. 1  illustrates the first coupling portion  477  and the second coupling portion  479  which are formed in a sphere shape as one example. 
     The second tub opening  43  may be open or closed by a second tub door  45  rotatably coupled to the upper surface of the second tub body  41 . The second tub door  45  is exposed outside the cabinet via the second opening  14 , when the second door  16  opens the second opening  14 . 
     The second tub door  45  may be located in a projected plane of the second opening  14  which is formed on the upper surface of the second tub body  41  to rotate toward outside the cabinet  1  via the second opening  14  when the second door  16  opens the second opening  14 . 
     The second drum  6  may be formed in any shapes only if provided in a shape rotatable in the second tub body  41   FIG. 1  illustrates the second drum  6  formed in a cylinder shape as one example. 
     In this instance, the second drum  6  may include a second drum body  61  located in the second tub body  41  and formed in a cylinder shape; a second drum opening  63  penetrating an upper surface of the second drum body and in communication with the second tub opening  43 ; and a plurality of penetrating holes  65  penetrating the second drum body and make an internal space of the second drum body  61  communicate with an internal space of the second tub body  41 . 
     The second drum opening  63  is located under the second tub opening  43 . When the user opens the second opening  14  by using the second door  16  and the second tub opening  43  by using the second tub door  45 , the second drum opening  63  is exposed outside the upper surface  12  of the cabinet. Accordingly, the user is able to load or unload clothes into or out of the second drum body  61  via the second opening  14 . 
     The second drum body  61  is rotatable by a second drive unit  67 . The second drive unit may include a second stator  671  fixed to a bottom surface of the second tub body  41  and forming a rotating field; a second rotor  673  rotatable by the rotating field; and a second shaft  675  connecting the second drum body  61  to the second rotor  673  through the bottom surface of the second tub body  41 . 
     The second shaft  675  may be provided to lie at right angles to the bottom surface of the cabinet  1 . The second drum opening  63  provided in the second drum body  61  is exposed outside via the upper surface  12  of the cabinet so that the second shaft  675  may be set to be arranged at an angle larger than zero and smaller than 90 degrees. 
     The second laundry treating device (second tub  4  and second drum  6 ) having the structure mentioned above supplies water to the second tub body  41  via a second water supply unit and drains the water stored in the second tub body  41  via a second drainage unit. 
     The second water supply unit may include a second water supply pipe  411  connecting the second tub body  41  to a water supply source; and a second valve  413  opening and closing the second water supply pipe according to a control signal of the controller. 
     The second drainage unit may include a second drainage pipe  415  guiding the water stored in the second tub body  41  toward the outside of the cabinet  1  and provided to pass a higher point than the maximum water level preset in the second tub body  41 ; and a second pump  417  for moving the water along the second drainage pipe. 
     Moreover, the implementation of the laundry machine  100  further include a hot air supply unit  9  for supplying heated air to the first tub body  21  or the second tub body  41 .  FIG. 1  illustrates the hot air supply unit  9  for supplying heated air to the first tub body  21  as one example. 
     The hot air supply unit  9  provided in the illustrated implementation may include a duct  91  providing a passage for exhausting internal air of the first tub body  21  outside the first tub body  21  and re-supplying the air to the first tub body  21 ; a fan  93  circulating the internal air of the first tub body  21  through the duct  91 ; and a heater  97  for heating the air drawn into the duct  91 . 
     One end of the duct  91  is connected to a first tub penetrating hole  27  penetrating the first tub body and the other end is connected to a second tub penetrating hole  29  penetrating the first tub body. The first tub penetrating hole  27  is configured to draw in the air having passed the heater into the first tub body  21  and the second tub penetrating hole  29  is configured to exhaust the internal air of the first tub body  21  to the duct  91 . 
     A cooling unit may be further provided in the duct  91  to remove the moisture contained in the air (e.g., dehydrating the air) by cooling the air moving toward the heater  97 . The cooling unit may be one example of a cold water supply unit for using an inner circumferential surface of the first tub body as space for air condensing by supplying cold water to the inner circumferential surface. In this instance, no condensing duct has to be provided advantageously. 
     The second laundry treating device (second tub  4  and second drum  6 ) of the implementation is located on the top of the first laundry treating device (first tub  2  and first drum  3 ). The higher the second laundry treating device is located, the more difficult it is for the user to load or unload clothes into or from the second laundry treating device. Accordingly, it is very important to adjust the heights of the second opening  14 , the second tub opening  43  and the second drum opening  63  in the laundry machine having the top second laundry treating device (second tub  4  and second drum  6 ) and the bottom first laundry treating device (first tub  2  and first drum  3 ). 
     To minimize the height of the cabinet, the duct  91  shown in  FIG. 2  may be fixed to the first tub body  21  to be located between an upper region of a circumferential surface of the first tub body  21  and the bottom surface of the second tub body  41 . The upper region of the circumferential surface of the first tub body  21  refers to the region located beyond a horizontal line (X, as horizontal line passing the rotation center of the first drum body) passing the center of the first tub body in the space defined by the first tub body  21 . 
     In some implementations, as mentioned above, the first tub body  21  is fixed in the cabinet  1  by the first tub supporting unit. 
     The first tub supporting unit may include a first spring for fixing the upper region of the circumferential surface of the first tub body  21  to the cabinet  1 ; a second spring for fixing the upper region of the circumferential surface to the cabinet  1 ; and a damper  255  for fixing a lower region of the circumferential surface to the cabinet  1 . 
     The damper  255  may be configured to dampen the vibration of the first tub body  21 . The first and second springs  251  and  253  may be configured to provide restitution to the first tub body  21  as well as dampening the vibration. 
     The damper  255  may be used in fixing the lower region of the circumferential surface of the first tub body  21  to the bottom surface or the lateral surface of the cabinet  1 . 
     The first spring  251  and the second spring  253  may be arranged in symmetry with each other with respect to a vertical line (Y as vertical line passing the rotation center of the first drum body) passing the center of the first tub body  21 . 
     When the first tub supporting unit of the present disclosure is provided with the structure mentioned above, the first spring  251  or the second spring  253  is likely to interfere with the duct  91 . Accordingly, the duct  91  may include a bending groove  911  for preventing the interference of the first or second spring  251  or  253  with the duct  91 . 
     The bending groove  911  is formed by concavely bending one surface of the duct  91  and the duct penetrating hole  913  penetrates the duct  91  to connect the first or second spring  251  or  253  to the first tub body  21  via the duct  91 . 
     In some implementations, it is more advantageous to the first spring  251  and the second spring  253  to provide elasticity to the first tub body  21 , as they are arranged more perpendicular with respect to the bottom surface of the cabinet  1 . Accordingly, the first spring  251  and the second spring  253  may be provided as shown in  FIG. 3 . 
     More specifically, the first spring  251  may be provided to connect the upper region of the circumferential surface of the first tub body  21  to the bottom surface of the second tub body  41  and the second spring  253  may be provided to connect the upper region of the circumferential surface to the bottom surface of the second tub body  41 . 
     The implementation of the laundry machine  100  above may include the top second laundry treating device (second tub  4  and second drum  6 ) and the bottom first laundry treating device (first tub  2  and first drum  3 ), and may be configured to prevent the first tub body  21  from interfering with the second tub body  41 . For example, the laundry machine  100  may be configured to prevent the vibration generated in the first tub body  21  in the operation of the first laundry treating device from being transferred to the second tub body  41  or the vibration generated in the second tub body  41  in the operation of the second laundry treating device from being transferred to the first tub body  21 . 
     As such, in some implementations the shortest distance (L 4 ) between the duct  91  and the second tub body  41  is formed to be more than the shortest distance (L 1 ) between the first tub body  21  and the cabinet  1 . 
     The shortest distance (L 1 ) between the first tub body  21  and the cabinet  1  is designed, considering the vibrating amplitude of the first tub body  21 . When the shortest distance ( 14 ) between the duct and the second tub body  41  is set as more than the shortest distance (L 1 ) between the first tub body and the cabinet, the risk of transferring the vibration generated in the first tub body  21  to the second tub body  41  may be minimized. 
     Moreover, when the shortest (L 4 ) between the duct  91  and the second tub body  41  is set as more than twice the shortest distance (L 1 ) between the first tub body  21  and the cabinet  1 , the risk may be effectively prevented that the vibration generated in the first tub body  21  is transferred to the second tub body  41 . 
     The vibration generated in the first tub body  21  might be transferred to the second tub body  41  via the second drive unit  67 , so that the shortest distance (L 3 ) between the second rotor  673  of the second drive unit and the first tub body  21  may be set to be equal to or more than twice the shortest distance (L 1 ) between the cabinet and the first tub body  21 . 
     In some implementations, the shortest distance (L 2 ) between the duct  91  and the cabinet  1  may be set as more than the shortest distance (L 1 ) between the first tub body  21  and the cabinet  1 , to prevent the vibration generated in the first tub body  21  from being transferred to the cabinet  1  via the duct  91 . 
       FIG. 4  illustrates another implementation of the laundry machine  100 . The illustrated implementation of the laundry machine  100  is characterized in that the hot air supply unit  9  includes a supply duct  92  for supplying external air to the first tub body  21 ; an exhaustion duct  94  for exhausting internal air of the first tub body  21  outside the cabinet  1 ; a fan  93  provided in the exhaustion duct  94 ; and a heater  97  for heating the air drawn into the supply duct  92 . 
     In this instance, the supply duct  92  may be located between the upper region of the circumferential surface of the first tub body  21  and the bottom surface of the second tub body  41 . The exhaustion duct  94  may be provided in the space formed between the cabinet  1  and the lower region of the circumferential surface of the first tub body  21  or a space formed between the upper region of the circumferential surface of the first tub body  21  and the bottom surface of the second tub body  41 . 
     Accordingly, when the fan  93  rotates, some of the air drawn into the cabinet via an external air inlet hole  19  is drawn into the first tub body  21  via the supply duct  92 . In that process, the air is heated by the heater  97 . 
     When the air heated via the supply duct  92  is drawn into the first tub body  21 , the internal air of the first tub body  21  is exhausted outside the cabinet  1  via the exhaustion duct  94  by the pressure inside the first tub body  21  so as to facilitate the drying of the clothes. 
     The implementations are described on a basis for the hot air supply unit  9  supplying heated air to the first tub body  21 . Alternatively, the hot air supply unit  9  may supply heated air to the second tub body  41 . 
     In this instance, the duct  91  has to be provided to circulate the internal air of the second tub body  41  and the supply duct  92  has to be provided to supply external air to the second tub body  41 . In some implementations, the exhaustion duct  94  may be arranged in the space formed between the upper region of the circumferential surface of the first tub body  21  and the bottom surface of the second tub body  41  and exhaust the internal air of the second tub body  41  outside the cabinet. 
     Hereinafter, implementations applicable to the present implementation will be described in detail, in an aspect of the hot air supply unit  9 . 
     As shown in  FIG. 1 , two washing units may be provided in on cabinet  1 . 
     In this example, a second tub  4  is provided beyond a first tub  2  and a second drive unit  67  is provided underneath a lower back surface of the second tub  4 . The second drive unit  67  includes a rotary second rotor  673 . Accordingly, a vertical space is formed between the two washing units and it is limited to increase such a space vertically. When both gaps are increased, the overall height of the cabinet is increased by a wide margin, and the increased overall height of the cabinet may make it difficult for a user to use the second washing unit. 
     Therefore, in some scenarios, there may be challenges in excluding the interference between the two washing units in such the narrow space. For example, wires or tubes may be arranged such the space, making it difficult to exclude the interference between such components and the second rotor  673 . 
     In some scenarios, there may be a risk of overheating the second stator  671  of the second drive unit  67 . For example, as the motor is driven, the temperature of the second stator  671  may rise. In such scenarios, it may be desirable to radiate the heat generated in the second stator  671  effectively. 
     In addition, such the narrow space makes it no easy to reduce the heights of the second tub  4  and the second drum  6 , because the laundry treating capacity could be remarkably reduced by decreasing the heights. It is possible to increase the capacity by enlarging a diameter more than the heights of the second tub  4  and the second drum  6  but it is limited by the size of the cabinet to increase the diameter. 
     To solve such disadvantages, the illustrated implementation illustrates that the lower back surface of the second tub  4  is projected upward. In other words, the lower back surface of the second tub  4  is recessed inward to the second tub  4 . Corresponding to such the shape of the second tub  4 , the shape of the second drum  6  may have a recessed portion inward to the second drum  6 . 
     Such different recessed portions may be provided in central portions of the second tub  4  and the second drum  6 , respectively. The second drive unit  67  may be provided in the center in which the recess is formed. 
     The lowermost portion of the second drive unit  67  is located higher than the lowermost portion of the second tub  4 . Especially, the lowermost portion of the rotary second rotor  763  may be located higher than the lowermost portion of the second tub  4  so that the second rotor  673  may rotate in a state of being surrounded by the second tub  4 . Even when the second rotor  673  is driven, the interference of the rotor with the other components located under the second tub  4  can be excluded. Even when a narrow space is provided between the first washing unit and the second washing unit, it is possible to use the washing units. 
     In some implementations, as the second drive unit  67  is provided in the narrow space, the heat generated in the second drive unit  67 , especially, the second stator  671  might fail to be radiated only to be transferred to the second tub  4 . As mentioned above, it is limited in reducing the height of the second tub  4  so that the lower thickness of the second tub  4  is relatively small. 
     The second tub  4  is formed of plastic and the second tub  4  made of plastic becomes more susceptible to heat as the lower thickness gets smaller. Also, the structural strength becomes reduced. Such the lower portion of the second tub  4  is the portion where the second drive unit  67  is mounted only to cause damage to the second tub  4  which is likely to deteriorate the strength. 
     Accordingly, heat damage prevention and strength reinforcement are required. 
     The illustrated implementation of the laundry machine may include a plate member  500  provided between the second drive unit  67 , in other words, a motor and an outer surface of the second tub  4 . The plate member  500  provided between the outer surface of the second tub  4  and the second stator  671  may facilitate smooth flow of heat in a radial direction. 
     The plate member  500  may be fixed to the outer surface of the second tub  4  or closely attached to the outer surface of the second tub  4 . 
     The second drum  6  is rotatable on a vertical shape and the outer surface where the plate member  500  is provided may be a lower back surface of the second tub  4 . 
     A portion of the plate member  500  may be inserted in the second tub  4  when injection-molding the second tub  4 , so that the portion of plate member  500  is integrally formed with the second tub  4 . For example, a center portion of the plate member  500  may be integrally formed with the second tub  4 , for example by inserting the center portion of the plate member  500  into the surface of second tub  4  during injection-molding of the second tub  4 . 
     In some implementations, the second shaft  675  of the second drive unit  67  penetrates the center of the second tub  4  and a bearing is provided to rotatably support the second shaft  675 . The bearing may be provided as a bearing housing. The center of the plate member  500  may be formed in a shape of a bearing housing. 
     In some implementations, as mentioned above, a drying duct  91  may be formed between the first washing unit and the second washing unit. The drying duct  91  may be connected to a front portion from a rear portion of the first tub  2 . 
     A heater  97  of the drying duct  91  may be configured to heat the air that is exhausted from the first tub  2  and re-supply the heated air into the first tub  2 . Accordingly, the temperature of the front portion may be higher than that of the rear portion in the drying duct  91 . For example, the amount of the evaporated moisture may be relatively small in an initial stage of the drying, and the temperature may be higher in the front portion than the rear portion of the drying duct  91 . 
     Accordingly, in such scenarios, high temperatures of the drying duct  91  are likely to affect the lower back surface of the second tub  4 . For example, the heat is likely to be transferred to the lower back surface, especially, a front portion of the lower back surface of the second tub  4 . 
     In some implementations, the plate member  500  is vertically overlapped with the drying duct  91 . For example, the plate member  500  may be provided in the front portion of the lower back surface of the second tub  4 . 
     As such, the plate member  500  may be not arranged in an entire portion of the lower back surface uniformly but instead may occupy a larger area of the front portion of the lower back surface in the second tub  4 . Accordingly, the plate member  500  may function to partition off the drying duct  91  from the second tub  4  so that heat transfer between the drying duct  91  and the second tub  4  may be reduced. 
     In some implementations, at least predetermined portion of the plate member  500  may be formed to cover the second stator  671  and the second rotor  673 . The heat rising in the second rotor  673  may be guided downward in a radial direction to be exhausted outside. 
     For that, an inclined portion  501  may be formed in the plate member  500 . The inclined portion  501  may be inclined downward from a center to a radial direction. Accordingly, heat may be guided along the inclined portion  501  radially and downward to be exhausted outside. 
     As a result, the heat inside the second rotor  673  may be exhausted easily so that cold air outside the second rotor  673  can be drawn into the second rotor smoothly enough to radiate the second stator  671 . As such, the plate member  500  may function to guide air flow as well as to mitigate heat transfer. 
     In some implementations, a downwardly recessed space, such as recess  4   b , is formed in the second tub  4 . The recess  4   b  may be connected to the second pump  417  and may correspond to the lowermost space where wash water is held in the second tub  4 . 
     In some implementations, the recess  4   b  may be configured to heat wash water. For example, a heater for heating wash water may be configured as part of the recess  4   b  so as to form a heating space. As such, water that is held in the second tub  4  may be heated in the recess  4   b.    
     The recess  4   b  may be downwardly recessed from the lower back surface of the second tub  4 , so that it may correspond to the lowermost portion of the second tub  4 . When the second drive unit is mounted such a portion, the overall height of the second tub  4  may be increased. Accordingly, in some implementations, the recess  4   b  is partitioned off from the space where the second drive unit is mounted. 
     As an example, a recess  4   a  projected upward may be formed in the center of the second tub  4  and the recess  4   b  may be formed in an outer portion along a radial direction of the recess  4   a . Accordingly, the lowermost portion of the recess  4   b  may be lower than the lowermost portion of the second rotor  673 . For example, the recess  4   b  may be provided to cover at least predetermined portion of the second rotor  673  by using the recess  4   a.    
     In some implementations, the plate member  500  may be configured so as not to cover the lower back surface of the second tub  4  corresponding to the lower portion of the recess  4   b . As such, the plate member  500  may be configured so as not to cover the recess  4   b . In such implementations, the recess  4   b  may be located in a rear portion of the second tub  4 . Wash water may be exhausted via the recess  4   b  and the length of the drainage pipe line may be reduced. 
     In some implementations, the plate member  500  may not be formed in an entire portion of the lower back surface of the second tub  4 . For example, the plate member  500  may extend to the front portion of the second tub  4 , but may not fully extend to a rear portion of the lower back surface of the second tub  4 . As a specific example, the plate member  500  may include an expanded portion  503  expanded from the center toward the front portion of the second tub  4  in an opposite direction to the recess  4   b . As such, the plate member  500  may be configured so as not to cover the recess  4   b.    
     In addition, the plate member  500  may include a center portion  502  surrounding the second shaft  675 . The center portion  502  may be formed as plane to be coupled to the second tub  4  stably. 
     The inclined portion  501  may be extended along a radial direction of the center portion  502 . Such the inclined portion  501  may be formed to surround the second rotor  673  from an outer portion in a radial direction of the second rotor  673 . The expanded portion  503  may be extended outward in a radial direction from the inclined portion  501 . 
     As mentioned above, the heat generated in the drying duct  91  might be transferred to the second tub  4  in the front portion of the lower back surface. In contrast, the heat generated in the second drive unit might be transferred to the drying duct  91 . Accordingly, the plate member  500  is provided to mitigate such heat transfer. 
     In addition, the heat generated in the second stator  671  is exhausted via the plate member  500  in a radial direction, so as to minimize the heat which might directly heat the drying duct  91 . 
     The plate member  500  may be made of metal and formed in a plate shape. The plate member  500  may be attached to the rear surface of the second tub  4  closely so as to reinforce the strength of the second tub  4  effectively. The plate member  500  may be molded with the rear surface of the second tub  4 , especially, the lower back surface. For that, a stepped portion may be formed so that the plate member  500  may be secured to the rear surface of the second tub  4  more closely. 
     In some implementations, the overall height of the second tub  4  may be determined by the recess  4   a  recessed upward from the center of the second tub  4  and the recess  4   b  recessed downward in the outer portion in the radial direction of the recess  4   a  to secure the second drive unit  67 . 
     The second drive unit  67  is secured in a state of being inserted in the recess  4   a  and the recess  4   b  is more recessed downward than the second drive unit  67 . Accordingly, the second rotor  673  may be located higher than the lowermost portion of the second tub  4  only to effectively prevent the driving of the second rotor  673  from interfering with the peripheral devices. 
     The plate member  500  may cover the second rotor  673 . Together with the plate member  500 , the recess  4   b  may cover the second rotor  673 . When a gap is formed between the second rotor and the plate member and between the plate member and the second rotor, the heat inside the second rotor  673  may be radiated and exhausted downward via the gap. 
     Referring to  FIGS. 1 through 4 , the implementation including the plate member  500  and the second stator  671  which are not secured to each other is described. 
     Hereinafter, referring to  FIG. 5 , one implementation including the plate member  500  and the second stator  671  which are secured to each other will be described. 
     As mentioned above, the plate member  500  may be coupled to or integrally formed with the lower back surface of the second tub  4 . The plate member  500  may be made of plastic and have a higher strength than plastic. Accordingly, in some implementations, the second stator  671  is secured to the plate member  500 , not directly secured to the second tub  4 . 
     For that, the center portion  502  of the plate member  500  may be extended more to the center of the radial direction and a securing portion for securing the second stator  671  may be formed in the center portion  502 . 
     First of all, the heat transferred via the second stator  671  may be radiated outside by the plate member  500  so as to improve the effective securing of the second stator  671  and the heat radiation effect. 
     In addition, the second drive unit  67  may be secured to the lower back surface of the second tub  4  more stably. 
     In some implementations, the two washing units according to the implementations mentioned above may not be separate and independent parts. In case one of the washing units is broken, the user is able to use the other one. However, if those washing units are in an inseparable relation, the user seems to recognize them as one product. Accordingly, the interference of the two washing units with each other may be excluded and the unnecessary heat transferring between the two washing units may be effectively shut off may be prevented by using the implementations mentioned above. Accordingly, the laundry machine may have enhanced reliability and durability. 
     Implementations of the present disclosure may be readily applied to other types of methods and apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations may be made. The features, structures, methods, and other characteristics of the exemplary implementations described herein may be combined in various ways to obtain additional and/or alternative exemplary implementations. As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described implementations are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be considered broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds, are therefore intended to be embraced by the appended claims.