Patent Publication Number: US-2022220655-A1

Title: Drum washing machine and fixing device for drum washing machine

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation application, which claims the benefit under 35 U.S.C. § 111(a) of PCT Application PCT/KR2021/016278 filed Nov. 9, 2021 which claim the benefit of Japanese Patent Application No. 2021-002299 filed on Jan. 8, 2021 and Korean Patent Application No. 10-2021-0115761 filed on Aug. 31, 2021. The contents of PCT Application No. PCT/KR2021/016278 filed Nov. 9, 2021 and Japanese Patent Application No. 2021-002299 filed on Jan. 8, 2021 and Korean Patent Application No. 10-2021-0115761 filed on Aug. 31, 2021 are incorporated by reference herein in their entirety. 
    
    
     FIELD 
     The present disclosure relates to a washing technique for a drum washing machine. 
     BACKGROUND 
     A drum washing machine is a washing device for generally washing flexible clothes, but various studies have been proposed so far to wash three-dimensional articles or things other than clothes. 
     For example, Patent Document 1 discloses a drum washing machine in which a partition plate is radially arranged inside a drum and the inside of the drum is divided into a plurality of small spaces to wash shoes. Patent Document 2 discloses a drum washing machine in which a pair of shoes are pressed and fixed on both sides of an inner circumferential surface of a drum with a rod-shaped mechanism so as to wash the shoes. 
     Regarding the disclosed technology, although it is not a washing machine, Patent Document 3 discloses an ion generator that sterilizes and deodorizes a helmet. 
     In addition, with respect to the disclosed technology, the present applicant has proposed a powerful drum washing machine capable of obtaining a washing effect superior to that of the conventional drum washing machine (Patent Document 4). In addition to the drum being rotatable in both forward and reverse directions, the drum washing machine includes a pulsator rotatable in both forward and reverse directions independently of the drum. Therefore, in a washing or rinsing process, both the drum and the pulsator are rotated independently of each other so as to increase the movement of the clothes. 
     PATENT LITERATURE 
     
         
         [Patent Document 1] Japanese Patent Laid-Open No. 2004-97317 
         [Patent Document 2] US 2003084585 A1 
         [Patent Document 3] Japanese Patent Laid-Open No. 2011-257059 
         [Patent Document 4] Japanese Patent Laid-Open No. 2020-110369 
       
    
     SUMMARY 
     When playing contact sports, such as American football, ice hockey, and lacrosse, players wear various protective equipment, such as helmets and protective gear. Because the protective equipment adheres to the player&#39;s body, a large amount of sweat, sebum, and dust attaches to the protective equipment after the play. 
     If the contaminated protective equipment is left unattended, it will not only become dirty, but also cause a bad odor. Therefore, there is a demand for such protective equipment to be washed as often as possible, like clothes. 
     Accordingly, protective equipment is relatively flexible in many cases and is divided into a plurality of members. Therefore, it is possible to wash most protective equipment using a washing machine. Therefore, it is possible to wash the protective gear relatively frequently, and thus the protective gear may be used in a clean state. 
     On the other hand, the helmet is formed in that a strong plastic material is wrapped around in a hat shape. Further, it is large in size and heavy, and thus it is not easy to wash the helmet. 
     When cleaning the helmet, a user has no choice but to wash the helmet after soaking the helmet or ask a professional company to do it. However, this is laborious and costly. Therefore, in general, the helmet is not washed after use, but is sprayed with a deodorizing spray or wiped off contamination. 
     It is difficult to wash helmets with a washing machine. Particularly, in the case of a drum washing machine, a wet object is lifted and dropped by the rotation of the drum, and the object is washed by using the impact (it is referred to as “beating washing”). 
     Therefore, objects that are washed with a drum washing machine are originally limited to flexible clothes and the like. In addition to helmets, when hard objects or heavy objects are washed with a drum washing machine, the drum and helmet are damaged by the impact of the drop. 
     The present disclosure is directed to providing a drum washing machine including a pulsator configured to be rotatable independently of a drum. According to the present disclosure, by utilizing a function of such a drum washing machine, it may be possible to wash things that may not be washed in the conventional washing machine. 
     That is, it may be possible to implement unexpected washing using a specific drum washing machine. 
     The disclosed technology is related to a drum washing machine. 
     One aspect of the disclosure provides a drum washing machine including a housing including an inlet formed on a front surface, a tub installed inside the housing to store water, a drum rotatably accommodated in the tub in a state in which an opening faces the inlet, a water supply device configured to supply water to the tub, a drainage device configured to discharge the water from the tub, a pulsator installed on a bottom of the drum and configured to be rotatable independently of the drum, a controller configured to control an operation of the water supply device and the drainage device and configured to control a rotation of the drum and the pulsator, and a fixing device configured to detachably fix an object to be washed having a three-dimensional shape to an inner lower side of the drum. 
     The controller may include a special washing processor configured to perform a washing operation of the object to be washed, and the special washing processor may be configured to perform a water storage operation for storing water in the tub in an amount, in which at least a part of the pulsator is submerged, and configured to perform a agitating operation for agitating the water inside the tub by rotating the pulsator in a state in which the drum is stopped to maintain a position of the object to be washed that is placed in the lower side. 
     That is, the drum washing machine may include the pulsator installed on the bottom of the drum and configured to be rotatable independently of the drum unlike a general drum washing machine. Therefore, the object to be washed having a three-dimensional shape that cannot be washed in the conventional drum washing machine may be detachably fixed to the inner lower side of the drum with the fixing device. 
     The special washing processor of the controller may store water in the tub in an amount, in which at least a part of the pulsator is submerged, by driving the water supply device, and perform the operation for agitating the water inside the tub by rotating the pulsator in a state of regulating a rotation of the drum to maintain the lower position of the object to be washed. 
     Accordingly, the pulsator may be rotated and thus the water stored in the drum may be agitated. Due to the small amount of water, the torque may be small and thus the pulsator may be rotated rapidly in a stopped state. Therefore, water may be agitated effectively. A lower portion of the object to be washed that is submerged may be washed by the flow of water. At the same time, the water stored in the drum may be raised high by the rotation of the pulsator and the water may be scattered upward of the object to be washed. An upper part of the object to be washed may be also washed by the scattered water. 
     Therefore, with the small amount of water, it is possible to effectively wash the object to be washed, which cannot be originally washed, using a specific drum type washing machine. 
     The drum washing machine may further include a drum stopper arranged between the tub and the drum and provided to mechanically couple the drum to the tub, and the rotation of the drum may be regulated by the drum stopper. 
     Accordingly, it is possible to stably regulate the rotation of the drum. 
     The drum washing machine may further include a motor configured to rotate the drum, and the rotation of the drum may be regulated by electrically controlling the motor. 
     In this case, the rotation of the drum may be regulated. Because it is electrically controlled, there is an advantage in that a mechanical mechanism is not required. 
     In the drum washing machine, in the water storage operation, water may be stored in the tub until a water surface is located below a center of the pulsator. 
     It is possible to effectively agitate the stored water as well as raising water high upward by the rotation of the pulsator, and thus it is possible to spray water from the upper side of the object to be washed. Further, it is possible to save water. 
     In the drum washing machine, the special washing processor may rotate the pulsator in both a forward rotation direction and a reverse rotation direction in the agitating operation. 
     By reversing the rotation direction of the pulsator, it is possible to improve an agitating action and a sprinkling action. Because the deflection of the flow of water and the sprinkling water are suppressed, the object to be washed may be washed in a balanced manner. 
     The drum washing machine may further include a water circulation mechanism configured to circulate the water stored in the tub by spraying the water into the drum, and the water circulation mechanism may be driven in response to the washing operation of the object to be washed by the special washing processor. 
     Because the water is sprayed to the inside of the drum, the upper part of the object to be washed may be further washed. Because the fluidity of the water stored in the tub and the drum is also increased, the lower part of the object to be washed may be further washed. 
     In the drum washing machine, the fixing device may include a holder mountable on an inner circumferential surface of the drum, and provided to support the object to be washed, and the object to be washed may be fixed to the lower inside of the drum through the holder. 
     Accordingly, it is possible to simply and stably fix the object to be washed to the inner lower side of the drum. 
     Particularly, it is suitable when the object to be washed is a helmet. 
     For example, the helmet may include a through hole formed on opposite sides of the helmet, and the holder may support the helmet through the through hole. 
     Particularly, the holder may include a first coupling member mountable to the inner circumferential surface of the drum, a second coupling member connectable to the first coupling member through a shaft portion, and the helmet may be supported by the holder by connecting the first coupling member to the second coupling member in a state in which the shaft portion is inserted into the through hole. 
     More particularly, the first coupling member may include a body connected to the second coupling member, a mounting plate elastically deformable and protruding from an outer edge portion of the body, and a magnet provided along an edge of the mounting plate. As the mounting plate is pressed against the inner circumferential surface of the drum by a magnetic force of the magnet, the holder may be fixed to the inner circumferential surface of the drum. 
     Accordingly, it is possible to simply and stably fix the helmet to the inner lower side of the drum. 
     The disclosed technology also relates to a washing method using a drum washing machine including a pulsator rotatable independently of the drum. 
     Another aspect of the present disclosure provides a washing method including a first step of removably fixing an object to be washed to an inner lower side of a drum through a fixing device; a second step of storing water to a tub in an amount, in which at least a part of a pulsator is submerged, and a third step of agitating the water inside the tub by rotating the pulsator in a state in which a rotation of the drum is regulated to maintain a position of the object to be washed that is placed in the lower side. 
     As described in the above-described drum washing machine, according to the washing method, it is possible to effectively wash the object to be washed, which cannot be originally washed, using a specific drum type washing machine with the small amount of water. 
     In the second step, water may be stored in the tub until a water surface is located below a center of the pulsator. In the third step, the pulsator may be rotated in both a forward rotation direction and a reverse rotation direction. In the third step, the water stored in the tub may be circulated by being sprayed into the drum. The same effect as the description of the above-described drum washing machine may be obtained. In addition, a fact that the object to be washed is a helmet may be the same as the description of the above-described drum washing machine. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a view illustrating laundry washing by a vertical washing machine. 
         FIG. 1B  is a view illustrating laundry washing by a drum washing machine. 
         FIG. 2  is a cross-sectional view schematically illustrating a structure of a drum washing machine according to one embodiment of the present disclosure. 
         FIG. 3  is a block diagram illustrating a relationship between a processor and a main related device. 
         FIG. 4  is a perspective view schematically illustrating an example of a universal fixing device. 
         FIG. 5  is a schematic view illustrating an example of a fixing device for a helmet, and a left drawing illustrates an exterior and a right drawing illustrates an internal structure. 
         FIG. 6  is a schematic view illustrating an example of a mechanical regulating means configured to regulate a rotation of a drum. 
         FIG. 7  is a flowchart illustrating a series of flows of a special washing operation. 
         FIG. 8  is a schematic diagram illustrating a main state in the special washing operation. 
         FIG. 9  is a view illustrating another example of the fixing device. 
         FIG. 10  is a view illustrating another example of the fixing device. 
     
    
    
     DETAILED DESCRIPTION 
     It is possible to wash things that is normally not conceivable, such as a helmet, by using a specific drum washing machine. 
     Embodiments described in the disclosure and configurations shown in the drawings are merely examples of the embodiments of the disclosure, and may be modified in various different ways at the time of filing of the present application to replace the embodiments and drawings of the disclosure. 
     In addition, the same reference numerals or signs shown in the drawings of the disclosure indicate elements or components performing substantially the same function. 
     Also, the terms used herein are used to describe the embodiments and are not intended to limit and/or restrict the disclosure. The singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. In this disclosure, the terms “including”, “having”, and the like are used to specify features, numbers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more of the features, elements, steps, operations, elements, components, or combinations thereof. 
     It will be understood that, although the terms first, second, third, etc., may be used herein to describe various elements, but elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the disclosure, a first element may be termed as a second element, and a second element may be termed as a first element. The term of “and/or” includes a plurality of combinations of relevant items or any one item among a plurality of relevant items. 
     In the following detailed description, the terms of “front side”, “rear side”, “left side”, “right side”, and the like may be defined by the drawings, but the shape and the location of the component is not limited by the term. 
     The disclosure will be described more fully hereinafter with reference to the accompanying drawings. The following description is merely exemplary in nature and is in no way intended to limit the present disclosure or its application or uses. 
     &lt;Type of Washing Machine&gt; 
     Home washing machines are broadly classified into vertical washing machines and drum washing machines.  FIGS. 1A and 1B  illustrate such washing machines. 
     As shown in  FIG. 1A , in general, a vertical washing machine puts clothes and a sufficient amount of washing water into a drum arranged in a water tub that is vertically placed, and washes the clothes with the water flow generated by agitating the stored washing water with a pulsator (agitating blade), (it is referred to as “rubbing washing”). 
     On the other hand, as shown in  FIG. 1B , in a drum washing machine, a drum is placed horizontally in a water tub. The drum is loaded with clothes and a small amount of washing water, and the drum is rotated to lift and then drop the clothes to mechanically wash the clothes (it is referred to as “beating washing”). Particularly, the drum washing machine may perform the washing with a smaller amount of water. Therefore, the drum washing machine has an advantage of saving water compared to the vertical washing machine. 
     However, in the case of a drum washing machine, because a strength of a mechanical action of beating-washing is largely determined by the fall of clothes according to the size of the drum, it is difficult to strengthen the washing power. It is conceivable to increase the number of rotations of the drum to increase the frequency of dropping, but even in this case, there is a limit because the clothes stick to the drum and do not fall if the rotation number is increased. 
     Accordingly, what the present applicant has proposed is a drum washing machine including a pulsator configured to be rotatable independently of the drum (hereinafter also referred to as “high-performance washing machine”; refer to Patent Document 4). The high-performance washing machine may provide an action of rubbing clothes with each other due to the movement of the clothes, as well as the mechanical action, such as “beating washing” obtained by the conventional drum washing machine. Therefore, the high-performance washing machine has superior washing power compared to the conventional drum washing machine. 
     The disclosed technology is an application of the high-performance washing machine. Therefore, the drum washing machine disclosed in one embodiment is based on the high-performance washing machine. 
     &lt;Drum Washing Machine&gt; 
       FIG. 2  illustrates a structure of the drum washing machine according to the present embodiment (hereinafter also referred to as a washing machine  1 ). The washing machine  1  includes a housing  10 , a tub  2 , a drum  3 , a pulsator  4 , a motor  5 , a processor  6  (controller), and the like. In addition, the washing machine  1  also includes a fixing device for washing a specific object to be washed different from clothes (the specific object to be washed and the fixing device will be described later). 
     In addition, the washing machine  1  is configured such that each of washing process, rinsing process, and spin-drying process are performed automatically according to a set program (fully automatic). The washing machine  1  of the present embodiment does not have a drying function. Accordingly, although the drying process is not performed, a drying device may be provided in the washing machine  1  to automatically perform the drying process. 
     The housing  10  is composed of a frame or a panel, and is formed in a box shape. A circular inlet  12  provided to be opened and closed by a door  11  is formed in a substantially center of a front surface of the housing  10 . Clothes enters and exits through the inlet  1 . A specific object to be washed also enters and exits through the inlet  12 . A control panel  13 , in which a monitor, a switch, and the like is arranged, is installed on a front upper portion of the housing  10 . The processor  6  is built in the rear of the control panel  13 . 
     The tub  2  is formed of a cylindrical container with a bottom provided to store water. The tub  2  is installed inside the housing  10  in a state in which an opening of the tub  2  is horizontally arranged toward the inlet  12 . In the washing process or the rinsing process, washing water or rinsing water is stored in a lower portion of the tub  2 . 
     A water supply device  21  configured to supply water to the tub  2  from an external water supply source through a pipe is installed above the tub  2 . Although not shown, a detergent tray is installed in the water supply device  21  to accommodate detergent and the like and send the detergent and the like to the tub  2  together with water when water is supplied. In addition, a drainage device  22  configured to discharge unnecessary water from the tub  2  is provided below the tub  2 . 
     In addition, the washing machine  1  is also provided with a water circulation mechanism configured to circulate the water stored in the tub  2  by spraying the water into the drum  3 . The water circulation mechanism may be composed of a circulation path including a circulation pump, a pipe and a hose, and a spray nozzle  8 . The spray nozzle  8  is installed above the opening of the tub  2  in a state in which a discharge port faces the inside of the drum  3 , as illustrated in  FIG. 2 . 
     A lower end of the circulation path is connected to a bottom of the tub  2 , and an upper end of the circulation path is connected to the spray nozzle  8 . The circulation pump is installed on the lower side of the circulation path. The circulation pump sends the water stored in the tub  2  toward the spray nozzle  8  through the circulation path under the control of the processor  6 . Because a structure of the water circulation mechanism is well-known, illustration except for the spray nozzle  8  will be omitted. 
     The drum  3  is composed of a cylindrical container including an opening  31  at one end and a bottom  32  at the other end. The drum  3  is mainly formed of a stainless-steel sheet. The drum  3  is accommodated in the tub  2  in such a way that the opening  31  faces the inlet  12  and the bottom  32  faces the rear side. The drum  3  is rotatable about a rotation axis J extending in a front and rear direction (the rotation axis J is approximately horizontal or inclined upward toward the front). 
     A plurality of through holes  33  penetrating the inside and outside is formed on a circumferential surface of the drum  3 . A plurality of lifters  35  is provided inside the drum  3 . Each lifter  35  is formed of a substantially columnar member having a substantially triangular cross-section. The lifter  35  protrudes inward from an inner circumferential surface of the drum  3  and extends in a direction parallel to the rotation axis J (rotation axis direction). Each lifter  35  is arranged at substantially constant intervals in the circumferential direction. 
     One pulsator  4  is installed at the bottom  32  of the drum  3 . The pulsator  4  is formed of a disk-shaped member having an approximately conical shape with a low vertex. A diameter of the pulsator  4  is formed slightly less than a diameter of the bottom  32  of the drum  3 . A surface of the pulsator  4  is provided with a plurality of protrusions  4   a  (three according to the embodiment) protruding and extending in a radial direction. 
     An inner shaft  2   a  and an outer shaft  2   b  that are rotated independently of each other are installed at the bottom  32  of the tub  2  (dual shaft structure). The drum  3  is connected to an upper end of the outer shaft  2   b . The pulsator  4  is connected to an upper end of the inner shaft  2   a  passing through the bottom  32  of the drum  3 . 
     Accordingly, the pulsator  4  and the drum  3  are rotated independently of each other about the rotation axis J. In addition, the outer shaft  2   b  and the inner shaft  2   a  are connected to the motor  5  arranged at the rear of the tub  2 . 
     (Motor  5 ) 
     The motor  5  may include a single stator, an inner rotor and an outer rotor arranged an inside and outside thereof. The inner rotor and the outer rotor are provided with permanent magnets forming a different number of magnetic poles, respectively. The outer shaft  2   b  is connected to the inner rotor. The inner shaft  2   a  is connected to the outer rotor. 
     The stator is shared by both the outer and inner rotors. That is, a compound current, in which the current corresponding to the number of magnetic poles of each rotor is superimposed, is supplied to the stator through inverter control. Accordingly, the two rotors are configured to be rotatable independently of each other. The motor  5  rotates the drum  3  and the pulsator  4  in a predetermined direction of forward rotation or reverse rotation, respectively, at a predetermined speed through the outer shaft  2   b  and the inner shaft  2   a  (dual rotor motor). 
     Such a motor is an example. As long as the drum  3  and the pulsator  4  are driven independently of each other, a driving mechanism may be selected according to the specifications. For example, the drum  3  and the pulsator  4  may be driven individually by two motors, respectively, or the drum  3  and the pulsator  4  may be driven by a single motor in which two rotors and two stators corresponding to the drum  3  and the pulsator  4  are integrally configured. 
     (Processor  6 ) 
       FIG. 3  illustrates a relationship between the processor  6  and the main related devices. The processor  6  is composed of hardware such as a CPU, a memory, and an interface, and software such as a control program and data mounted on the hardware. The processor  6  is electrically connected to the control panel  13 , the motor  5 , the water supply device  21 , the drainage device  22 , and the like. 
     Based on a signal input from the control panel  13 , the processor  6  outputs a control signal to the motor  5  or the like and comprehensively controls the washing machine  1 . The processor  6  is provided with a general washing processor  6   a  and a special washing processor  6   b  for controlling the washing machine  1  as a functional configuration. The general washing processor  6   a  may be a general washing portion  6   a  or a general washing unit  6   a , and the special washing processor  6   b  may be a special washing portion  6   b  or a special washing unit  6   b.    
     The general washing processor  6   a  performs an original washing operation of the washing machine for clothes. That is, the general washing processor  6   a  automatically performs a series of processes including a washing process, a rinsing process, and a spin-drying process. 
     For example, the general washing processor  6   a  supplies a predetermined amount of washing water or rinsing water to the tub  2  by operating the water supply device  21  in the washing process and the rinsing process. The general washing processor  6   a  controls the motor  5  to rotate the pulsator  4  and the drum  3  in the same direction or in the counter direction while switching at a predetermined timing. 
     The general washing processor  6   a  operates the drainage device  22  to discharge the water stored in tub  2 . In the spin-drying process, the general washing processor  6   a  controls the motor  5  to synchronize and rotate the pulsator  4  and the drum  3  in the same direction while operating the drainage device  22  to discharge the water from the tub  2 . Accordingly, it is possible to spin-dry the clothes by using the centrifugal force. 
     On the other hand, by a special washing method using a fixing device, the special washing processor  6   b  performs a washing operation (special washing operation) of a specific object to be washed different from clothes. The special washing operation will be described later in detail. 
     &lt;Object to be Washed with Special Washing Operation&gt; 
     A specific example of the object to be washed in the special washing operation includes a helmet worn in contact sports, such as American football, ice hockey, and lacrosse. A specific example of the object may include a helmet worn in cycling sports, such as cycling or mountain biking. 
     The specific example of the object is not limited to a helmet, and the specific example of the object may include other sports gear worn in sports, such as ski boots and goggles. Further, the object may include safety gear worn in work involving physical labor, such as construction work, machining work, agriculture, etc. In addition, the object is not limited to the sports gear and the safety gear, and may include various mechanisms. That is, as long as a thing that is washable with water and has a three-dimensional shape that can be accommodated in the drum  3 , the thing may correspond to the object to be washed. 
     &lt;Fixing Device&gt; 
     The fixing device is used to detachably fix the object, which is to be washed, accommodated in the drum  3 , to the drum  3 . The fixing device may prevent the object to be washed from moving inside the drum  3  even when the force of the water flow is applied during the washing operation. However, because it is required for the fixing device to enter and exit through the inlet  12 , it is appropriate that a user can easily handle the fixing device. Further, it is appropriate that the fixing device is used for various objects to be washed. 
     (Universal Fixing Device) 
       FIG. 4  illustrates an example of the fixing device. The fixing device  40  includes a holder  41  formed of a plastic material and formed to have a cross section in an arc shape according to a shape of the inner circumferential surface of the drum  3 . The holder  41  is provided in such a way that a plurality of grid plates  41   a  and  41   b  (three grid plates on the drawings) is connected rotatably in the circumferential direction so as to be foldable. 
     Each plate  41   a , and  41   b  is formed in a grid shape by installing a rib between rectangular frames. The holder  41  includes a single center plate  41   a  and two side plates  41   b  and  41   b  connected to opposite sides of the center plate  41   a . At a predetermined position on an inner surface of the center plate  41   a , a display projection  42  defining an interference position with the pulsator  4  is provided. 
     A width of each plate  41   a , and  41   b  is set to be approximately the same size, and by folding the two side plates  41   b  and  41   b  toward the center plate  41   a  side, the width of the plate may be reduced to approximately ⅓. A length of each plate  41   a , and  41   b  is approximately equal to a length of the inner circumferential surface of the drum  3  in the front and rear direction, and the holder  41  is designed to be fitted in the front and rear direction inside the drum  3  so as to prevent the distortion. 
     The holder  41  is also designed to be accommodated between two lifters  35  and  35  adjacent to each other in a state in which the holder  41  is unfolded along the inner circumferential surface of the drum  3 . The holder  41  may be designed to be fitted between the two lifters  35  and  35  in response to being accommodated in the drum  3 . In addition, a magnet may be provided on a rear surface of the holder  41  to allow the holder  41  to be suctioned to the inner surface of the drum  3  by a magnetic force. 
     The holder  41  may enter and exit from the inlet  12  in a folded state. Therefore, it is easy to handle the holder  41 . The holder  41  is unfolded inside the drum  3  so as to be mounted on the inner circumferential surface of the drum  3 . In this case, by arranging the holder  41  to place the protrusion  42  to the inside of the drum  3 , a position interfering with the pulsator  4  may be easily recognized 
     The fixing device may further include a restraining tool (not shown) configured to install the object to be washed to the holder  41 . By installing the object to be washed to the holder  41  with a restraining tool, the object to be washed may be fixed to the lower portion of the drum  3  through the holder  41 . 
     It is appropriate that the restraining tool includes a rope or a net including a hook provided at a tip and adjustable in length. With the restraining tool, the object to be washed may be easily tied by hooking a hook to the grid rib of the holder  41 . 
     (Fixing Device for Helmet) 
       FIG. 5  illustrates a fixing device  50  for a helmet. The fixing device  50  is mainly for the helmet  100  for sports. As illustrated in the cross-section in  FIG. 5 , ear covers  101  and  101  for protecting ears are generally provided on opposite sides of the helmet  100 . In the ear cover  101  and  101 , a through hole  101   a  is formed on a portion corresponding to the user&#39;s ear so as not to interfere with hearing. 
     The shape of the ear cover  101  including the through hole  101   a  is almost constant. Therefore, it is appropriate to support the helmet  100  using the through hole  101   a  (the through hole  101   a  is used according to the embodiment). When through holes are provided on opposite sides of the helmet  100 , it may be used to support the helmet  100  even if the through holes  101   a  are not present. 
     Particularly, the fixing device  50  includes a first coupling member  60  and a second coupling member  70 . The first coupling member  60  is provided to be mountable on the inner circumferential surface of the drum, and the second coupling member  70  is provided to be connected to the first coupling member  60  with each other. 
     The first coupling member  60  includes a body  61  formed in a disc shape having a greater diameter than the through hole  101   a , and including an insertion hole  62  provided at a center of a surface of the body  61 , a first pressing portion  63  formed in a ring shape formed of an elastic member and installed around the insertion hole  62  on the surface of the body  61 , and a mounting plate  64  elastically deformable and protruding from an outer edge portion of the body  61 . The mounting plate  64  may correspond to an elastic plate  64 . 
     The first pressing portion  63  and the mounting plate  64  are formed of an elastic member such as rubber or silicone. A plurality of magnets  65  is provided at an outer circumferential side edge of the mounting plate  64  at intervals along the circumferential direction of the edge. 
     The second coupling member  70  includes a fitting portion  71  formed in a disc shape having a greater diameter than the through hole  101   a , and including a shaft portion  72  provided at a center of the fitting portion  71 , a second pressing portion  73  formed in a ring shape formed of an elastic member and installed around the shaft portion  72  of the fitting portion  71 , and a handle portion  74  connected to a portion opposite to the shaft portion  72  of the fitting portion  71 . The shaft portion  72  is provided to be fitted from a tip thereof to a predetermined position in the insertion hole  62 , and provided to be detachable from the insertion hole  62 . 
     Accordingly, after inserting the shaft portion  72  of the second coupling member  70  from the inside of one side of the ear cover  101  into the through hole  101   a , the shaft portion  72  protruding from the through hole  101   a  is inserted into the insertion hole  62  of the first coupling member  60 . Accordingly, the first coupling member  60  and the second coupling member  70  are connected to each other so as to allow the ear cover  101  to be elastically supported on opposite sides by the first pressing portion  63  of the first coupling member  60  and the second pressing portion  73  of the second coupling portion  70 . Accordingly, it is possible to install the fixing device  50  to the helmet  100 . 
     In response to mounting the fixing device  50  to the inner circumferential surface of the drum  3  from the side of the first coupling member  60 , the mounting plate  64  is deformed by the magnetic force of the magnet  65  and pressed against the inner circumferential surface of the drum  3 . Therefore, even on the inner circumferential surface of the drum  3  having a curved surface, the helmet  100  may be removably fixed to the inner lower side of the drum  3  simply. 
     &lt;Special Washing Operation&gt; 
     As described above, in the washing machine  1 , the special washing processor  6   b  is provided in the processor  6 , and thus the washing machine  1  is configured to perform the special washing operation for a specific object, which is to be washed, through a special washing method using the fixing device  50 . 
     (Rotation Regulation of Drum  3 ) 
     In the special washing operation, the washing process and/or the rinsing process are performed, and the spin-drying process is not performed. In addition, in the washing process, only the pulsator  4  is rotationally driven (agitating operation) in order to agitate the water inside the drum  3 , and the drum  3  is not rotationally driven. The rotation of the drum  3  is regulated at a predetermined position to maintain the pulsator  4  in a submerged state. 
     (Mechanical Regulating Means) 
     The washing machine  1  is configured to perform the rotation regulation of the drum  3  by using a mechanical regulating means. Particularly, a drum stopper configured to mechanically couple the drum  3  to the tub  2  is arranged between the tub  2  and the drum  3 . For example, the washing machine  1  may include a drum stopper hooked and coupled to between the tub  2  and the drum  3 . Therefore, the rotation of the drum  3  is regulated by driving the drum stopper. 
       FIG. 6  illustrates a coupling pin  80  as an example of the drum stopper. The coupling pin  80  is provided between a flange portion  31   a  extending along the outer circumference of the opening  31  of the drum  3 , and an opposite flange portion  2   a  of the tub  2  opposite to the flange portion  31   a . The coupling pin  80  is supported to protrude toward the corresponding flange portion  31   a  by a support member  81  provided on the flange portion  31   a.    
     A concave portion  82  is formed at a predetermined position of the opposite flange portion  2   a . By pressing the coupling pin  80  in a state in which the coupling pin  80  and the concave portion  82  are aligned, the coupling pin  80  protrudes from the support member  81 , and a tip thereof is inserted into the concave portion  82 . Accordingly, the rotation of the drum  3  is regulated at a predetermined position. 
     The concave portion  82  is not essential. By pressing the coupling pin  80 , the tip of the coupling pin  80  may be pressed against the opposite flange portion  2   a . A coupling hole, into which the coupling pin  80  is inserted, is formed in the flange portion  31   a , and in the state in which the coupling hole and the concave portion  82  are aligned, the tip of the coupling pin  80  inserted into the coupling hole may be inserted into the concave portion  82 . That is, the drum stopper only needs to hold the drum  3  at a predetermined position during the agitating operation. 
     The operation of inserting or removing the coupling pin  80  may be performed manually or may be performed automatically through electrical control by the processor  6 . In the washing machine  1 , the case in which the operation of inserting or removing the coupling pin  80  is performed manually is describe as an example. 
     (Electrical Regulating Means) 
     In a state in which each rotor of the motor  5  is controlled by an individual inverter or a state in which the drum  3  is driven by a dedicated motor (drum motor) independently of the driving of the pulsator  4 , the rotation regulation of the drum  3  may be performed by an electrical means. 
     For example, in the former case, a three-phase current is supplied to prevent the generation of the rotational force by controlling an inverter configured to supply a current to the inner rotor configured to rotate the drum  3 . Accordingly, the inner rotor is not rotated. Therefore, the rotation of the drum  3  may be regulated. 
     Alternatively, it is also possible to use short break control. That is, the so-called short-brake control, which stops the rotation of the motor by controlling a switching circuit of the inverter to cut off electricity to the motor, is generally used for shortening a spin-drying time (short-brake control is well-known technology and thus a description thereof will be omitted). 
     Particularly, in the performance of the special washing operation, the short-brake control is performed on the inverter configured to supply the current to the inner rotor. Accordingly, energization of the inner rotor is cut off, and the inner rotor is electrically disconnected. Therefore, the inner rotor is not rotated, and the rotation is suppressed by the action of the permanent magnet provided in the inner rotor. Therefore, the rotation of the drum  3  may be regulated. 
     In the latter case, in response to stopping the driving of the drum motor, the rotation of the drum  3  may be stopped. The rotation of the drum  3  may be regulated by the short-brake control of the inverter of the drum motor. 
     (Special Washing Method Using the Fixing Device) 
     Hereinafter a special washing method using the fixing device will be described. The washing method mainly includes three steps, and the three steps are performed in the washing process or the rinsing process of the special washing operation. 
     That is, the washing method includes a first step of removably fixing the object to be washed to the inner lower side of the drum  3  through the fixing device, a second step of supplying water in an amount in which at least a part of the pulsator  4  is submerged in the tub  2 , and a third step of agitating the water stored in the drum  3  by rotating the pulsator  4  in a state in which the rotation of the drum  3  is regulated to allow the object, which is to be washed, to be placed on the lower side. 
     The first step is mainly performed by a user. The second and third steps are performed by the washing machine  1  (processor  6 ).  FIG. 7  illustrates a series of process flow including the steps.  FIG. 8  illustrates a main state of the washing machine in the process of the operation. In the following description, the helmet  100  for sports such as American football is described as the object to be washed. 
     A user who wants to wash the helmet  100  manipulates the control panel  13  to select a driving mode (special washing mode) for performing the special washing operation, and starts driving the washing machine  1 . Accordingly, in the washing machine  1 , a signal for instructing of a special washing mode operation is received through the control panel  13  to the processor  6 . At this time, in the case of washing with water, the user proceeds with the process as it is, but in the case of using detergent, etc., the user inputs the detergent to the detergent tray in advance. 
     The processor  6  determines whether or not the operation of the special washing mode is started based on the signal received through the control panel  13  ( 1 ). Therefore, in response to determining that the operation of the special washing mode is started, the special washing operation is started by the special washing processor  6   b  of the processor  6 . 
     In response to the start of the special washing operation, the processor  6  urges the user to perform the regulation of the rotation of the drum  3 , that is, inserting the coupling pin  80 , through a monitor of the control panel  13 . At the same time, through the monitor of the control panel  13 , the processor  6  urges the user to perform the first step, that is, to install the helmet  100  to the inner lower side of the drum  3  ( 2 ). 
     Accordingly, the user rotates the drum  3  to align the coupling pin  80  and the concave portion  82 , and then pushes the coupling pin  80  into the concave portion  82 . Accordingly, the drum  3  is fixed in a predetermined position. 
     The user also installs the fixing device  50  to the contaminated helmet  100 . Particularly, the fixing device  50  is installed to one side of the ear cover  101  of the helmet  100 . 
     As illustrated in  FIG. 8A , the helmet  100  is accommodated in the drum  3  through the inlet  12 , and the fixing device  50  is installed at the lower inside of the drum  3 . At this time, because the mounting plate  64  is deformed and pressed against the inner circumferential surface of the drum  3  by the magnetic force of the magnet  65 , the user can simply operate the fixing device  50  even if the helmet  100  is placed. As a result, the helmet  100  may be fixed to the inner lower side of the drum  3  through the fixing device  50 . 
     In addition, at this time, it is required to arrange the helmet  100  so as not to contact the pulsator  4 . Because the shape and size of the helmet  100  vary, it is difficult to properly arrange the helmet  100  in the conventional manner. However, because the fixing device  50  is attached to the drum  3  by only the action of magnetic force, the position may be easily adjusted only by changing the position of the helmet  100  against the suction force. 
     After the helmet  100  is fixed to the inner lower side of the drum  3 , the user closes the door  11 . The user inputs an operation completion command to the processor  6  by manipulating a button or the like displayed on the monitor of the control panel  13 . 
     In response to the operation completion command not being input for a predetermined period of time (no in  3 ) or in response to the door  11  not being closed for a predetermined period of time (no in  4 ), the processor  6  notifies the user of an abnormality by an alarm or the like ( 15 ). The processor  6  terminates the special washing mode without performing the special washing operation. 
     On the other hand, in response to the operation completion command being input and in response to determining that the door  11  is closed, the processor  6  starts the special washing operation. That is, the special washing processor  6   b  drives the water supply device  21  to start a water storage operation (water storage process) ( 5 ). An amount of water supply is pre-set in the processor  6 . In the special washing operation, washing is performed using agitating and sprinkling action, not by the beating washing. For this purpose, an amount of water supply for the special washing operation is greater than that of the general washing operation for clothes. 
     Therefore, it is required to supply water in an amount, in which at least a part of the pulsator  4  is submerged, to the drum  3 . It is possible to supply the maximum amount of water that can be stored in the tub  2 , but it is appropriate to supply an amount of water that submerges a lower portion of the helmet  100 , that is supplying water until a water surface is under the center of the pulsator  4 , as shown in  FIG. 8B . The water surface of the tub  2  and/or the drum  3  may be the water level of the tub  2  and/or the drum  3 . 
     It is possible to effectively agitate the stored water as well as raising water high upward by the rotation of the pulsator  4 , and thus it is possible to spray water from the upper side of the helmet  100 . Further, it is possible to save water. 
     The processor  6  determines whether or not the amount of water supply reaches a set water amount Wo ( 6 ), and in response to determining that the amount of water supply reaches the set water amount (yes in  6 ), the processor  6  stops the water supply and starts the agitating operation (agitating process) by driving the motor  5  ( 7 ). 
     The rotation of the drum  3  is regulated by the connection of the coupling pin  80  and the concave portion  82 . As a result, the helmet  100  is always positioned in the lower side in the drum  3  and thus the submerged state is maintained. In this state, the pulsator  4  is rotated and the agitating operation is performed. 
     As the pulsator  4  is rotated, the water stored in the drum  3  is agitated. Due to the small amount of water, the torque is small and thus the pulsator  4  is rotated rapidly in a stopped state. Therefore, water may be agitated effectively. A lower portion of the helmet  100  that is submerged may be washed by the flow of water. At the same time, the water stored in the drum  3  is raised high by the rotation of the pulsator  4 , and the water is scattered upward of the helmet  100 . The upper part of the helmet  100  is also washed by the scattered water. 
     At this time, the rotation of the pulsator  4  may be in a constant direction, but it is appropriate to reverse the rotation direction, as shown in  FIG. 8C . Particularly, it is more appropriate to alternately rotate the pulsator  4  in the forward rotation direction and the reverse rotation direction for the same period of time. Particularly, the processor  6  controls the driving of the motor  5  to allow the pulsator  4  to be alternately rotated in both the forward rotation direction and the reverse rotation direction in a short time. 
     By reversing the rotation direction of the pulsator  4 , it is possible to improve the agitating action and the sprinkling action. Because the deflection of the flow of water and the sprinkling water are suppressed, the helmet  100  may be washed in a balanced manner. 
     In response to determining that a period of time reaches a preset operation time T 0  (yes in  8 ), the processor  6  stops the agitating operation ( 9 ). 
     The processor  6  performs a drainage operation. That is, the processor  6  drives the drainage device  22  to start an operation of draining water from the tub  2  ( 10 ). In response to determining that a predetermined time T 1  for completing the drainage elapses (yes in  11 ), the processor  6  stops draining and notifies a user that the operation is completed by an alarm or the like ( 12 ). 
     In addition, through the monitor of the control panel  13 , the processor  6  urges the user to release the rotation regulation of the drum  3 , that is to take out the coupling pin  80 . At the same time, through the monitor of the control panel  13 , the processor  6  urges the user to take out the helmet  100  from the inside of the drum  3  ( 13 ). 
     Accordingly, the user pulls out the coupling pin  80  from the concave portion  82 . Therefore, the rotation regulation is released, and the drum  3  becomes rotatable. The user also takes out the helmet  100  together with the fixing device  50  from the drum  3 . At this time, because the fixing device  50  is attached to the drum  3  by only the action of magnetic force, the fixing device  50  may be easily taken out together with the helmet  100 . 
     Finally, in response to the operation completion command being input to the processor  6  by manipulating a button displayed on the motor of the control panel  13  by the user, the series of special washing operation is terminated (yes in  14 ). The user may take out the helmet  100  and remove the fixing device  50  from the helmet  100  and dry the helmet  100  by wiping off the remaining water or drying the helmet  100  in the shade. 
     On the other hand, in response to the operation completion command not being input for the predetermined period of time (no in  14 ), the processor  6  notifies the user of an abnormality through an alarm or the like ( 15 ). 
     The user may change the direction of the helmet  100  and perform the special washing operation a plurality of times. In addition, in the case of washing by adding detergent, it is appropriate to perform the special washing operation with only water in order to additionally perform rinsing by washing with water. A detergent washing mode may be provided in the washing machine  1  and thus the special washing processor  6   b  continuously performs the washing process and the rinsing process. 
     Application Example 
     In the above-described washing method, the helmet  100  is washed by using the agitating operation by the rotation of the pulsator  4 , but a water circulation mechanism may be further used. 
     That is, the washing machine  1  is provided with a water circulation mechanism configured to circulate the water stored in the tub  2  by spraying the water into the drum  3 . The special washing processor  6   b  drives the water circulation mechanism while performing the agitating operation during the special washing operation. 
     Because the water is sprayed from the spray nozzle  8  toward the inside of the drum  3 , the upper part of the helmet  100  may be further washed. Because the fluidity of the water stored in the tub  2  and the drum  3  is also increased, the lower part of the helmet  100  may be further washed. The water circulation mechanism may be continuously or intermittently driven during the performance of the special washing operation. 
     The drum washing machine according to the disclosed technology is not limited to the above-described embodiment, and may include various other configurations. For example, the shape of the fixing device may be appropriately changed according to the object to be washed. The shape of the fixing device that is employable is exemplified in  FIGS. 9 and 10 . 
     A fixing device  90 A illustrated in  FIG. 9A  includes a mesh net  91  formed in a bag shape and a hook  92  for fixing. The mesh net  91  may include an opening configured to be opened or closed and thus the helmet  100  may be inserted or withdrawn through the opening. The hooks  92  are installed at a plurality of places spaced apart from each other in the mesh net  91 . 
     The hook  92  may be fixed by being hooked on a drain hole (not shown) formed in the lifter  35 . The fixing device  90 A is used in such a way that the mesh net  91 , in which the helmet  100  is placed and the opening thereof is closed, is accommodated in the drum  3  and then the hook  92  is hooked and fixed to the lifter  35 . 
     A fixing device  90 B illustrated in  FIG. 9B  is an application example of the fixing device  90 A illustrated in  FIG. 9A . In addition to the mesh net  91  and the hook  92 , a line  93  provided to connect the hook  92  to the mesh net  91  is provided. It is possible to reduce the size of the mesh net  91  by a length of the line  93 . 
     A fixing device  90 C illustrated in  FIG. 9C  includes a circular frame  94  having a diameter smaller than the inner diameter of the drum  3 , a mesh net  95  provided on the circular frame  94 , and a plurality of hooks  92  provided around the circular frame  94  in correspondence with each lifter  35 . 
     The fixing device  90 C is installed and used so as to divide the inside of the drum  3  into a front space and a rear space. The helmet  100  and the like are accommodated in the front space of the drum  3  partitioned by the fixing device  90 C. 
     A fixing device  90 D illustrated in  FIG. 10D  is an application example of the fixing device  90 C illustrated in  FIG. 9C . The fixing device  90 D includes an arcuate frame  96 , a mesh net  97  provided on the arcuate frame  96 , and two hooks  92  and  92  provided on opposite sides of the arcuate frame  96  in correspondence with each lifter  35 . 
     A fixing device  90 E illustrated in  FIG. 10E  is a fixing device  90  for exclusive use of the helmet. The fixing device  90 E is formed of metal or resin having flexibility, and includes a first hook portion  98   a  hooked on the opening of the drum  3  and a second hook portion  98   b  hooked on the helmet  100 . For washing the helmet  100 , the helmet  100  is fixed to the drum  3  through the fixing device  90 E. 
     A fixing device  90 F illustrated in  FIG. 10F  is an application example of the fixing device  90 B and the fixing device  90 E. The fixing device  90 F includes a mesh net  91  and a first hooking portion  98   a.    
     While the present disclosure has been particularly described with reference to exemplary embodiments, it should be understood by those of skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the present disclosure.