Patent Publication Number: US-7213423-B2

Title: Washing machine

Description:
This application claims the benefit of the Korean Application No. 2002-47800 filed on Aug. 13, 2002, which is hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a washing machine, and more particularly, to a washing machine capable of minimizing tangle and damage of the laundry and decreasing usage of the wash water. 
   2. Discussion of the Prior Art 
   Generally, washing machine is an apparatus in which energy such as impact or the like is applied to the laundry so as to remove contaminants. According to the applying method of the energy, the washing machines are classified into the pulsator washing machine, drum washing machine and agitator washing machine. In the drum washing machine, the laundry is dropped and impacted by the rotation of the drum, to be washed. In the pulsator washing machine and the agitator washing machine, the rotation of the pulsator or agitator coupled to the washing shaft perpendicular installed at the inner tub allows the laundry to impact, and the wash action of detergent is added thereto, so that wash is performed. In other words, the aforementioned washing machines utilize a method in which impact is applied to the laundry by a mechanical method to perform the washing. 
   Referring to  FIG. 1 , a conventional pulsator washing machine will be now described as follows. 
   An outer tub  3  for containing wash water is installed inside a case  1  of the washing machine, an inner tub  5  is installed inside the outer tub  3  and is impacted, and a pulsator  7  is installed inside the inner tub  5 . A motor  9  for rotating the inner tub  5  and the pulsator  7  is installed below the outer tub  3 . 
   In more detail, a dehydration shaft  15  is coupled with the inner tub  5 , a wash shaft  13  that can be selectively coupled with the dehydration shaft  15  is installed inside the hydration shaft  15 , and the pulsator  7  is rotatably installed at a predetermined portion of the wash shaft  13 . 
   The rotational force of the motor  9  is selectively transferred to the inner tub  5  and the pulsator  7  by a clutch assembly  11 . Also, the wash shaft  13  and the dehydration shaft  15  are selectively serration-coupled by a solenoid  11   a.    
   Referring to  FIG. 1 , operation of the conventional pulsator washing machine will be described as follows. 
   First, wash cycle is described as follows. Laundry is loaded into the interior of the inner tub  5 , and the washing machine is driven, so that wash water is supplied into the inner tub  5 . After the completion of the wash water supply, in a state where the laundry is dipped in the wash water, the pulsator  7  is rotated in the forward or backward direction to wash the laundry. In other words, the rotational force of the motor  9  is transferred to the pulsator  7  through the wash shaft  13 , and washing is performed by water stream generated by the stirring of the pulsator  7  and friction between the pulsator  7  and the laundry. 
   Next, dehydration cycle is described. In the dehydration cycle, the wash shaft  13  and the dehydration shaft  15  are rotated as if they are one body by the operation of the solenoid  11   a . In other words, the inner tub  5  and the pulsator  7  are rotated at a high speed together to perform the dehydration. 
   As aforementioned, the conventional washing machine carries out the washing by stirring the pulsator to rub the laundry in a state where the laundry is dipped in the wash water, or by water stream. 
   Accordingly, the conventional washing machine is difficult to avoid tangling or damage of the laundry. Also, since the conventional washing machine carries out the washing in a state where the laundry is dipped in the wash water, the amount of the wash water and the amount of the detergent increase, and a total washing time is lengthened due to the increase in the supply and drain time of the wash water not directly related with the washing time. 
   SUMMARY OF THE INVENTION 
   Accordingly, the present invention is directed to a washing machine that substantially obviates one or more problems due to limitations and disadvantages of the related art. 
   An object of the present invention is to provide a washing machine capable of minimizing tangle and damage of the laundry. 
   Another object of the present invention is to provide a washing machine capable of saving usage amount of the wash water. 
   Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
   To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a washing machine includes: a wash shaft installed perpendicularly at a lower center of an inner tub, and rotated by a rotational force transferred from a motor; a wash plate orbiting about a rotational center of the wash shaft to form a stream of water; and a movement converting unit for converting a rotational movement of the wash shaft to a orbiting movement of the wash plate. 
   Preferably, the movement converting unit includes a base having an eccentric shaft formed in an upper portion thereof, the eccentric shaft being coupled to the wash plate and a lower portion of the base being coupled to the wash shaft. 
   Preferably, the movement converting unit further includes a counterweight for correcting imbalance in the weights of the base and the wash plate. 
   Alternatively, a pumping passage is installed at one side of the inner tub, and a pumping means rotating according to the rotation of the wash shaft to pump the wash water of the inner tub to the pumping passage is installed at the lower side of the base. Preferably, the pumping means is a plurality of blades formed from the center of the inner tub along an outer circumferential direction. 
   Preferably, the movement converting unit further includes a wash plate adapter of which one side is coupled to the eccentric shaft and the other side is coupled to the wash plate. 
   Preferably, a bearing is installed between the eccentric shaft and the wash plate adapter, and the bearing has a construction capable of transferring the rotational force in one side direction. Preferably, a sealer is installed below the bearing. 
   Alternatively, a self-rotation preventing member for preventing the rotation of the wash plate is installed between the wash plate and the inner tub. 
   Preferably, a protruded portion is formed below the eccentric shaft, and a cap is installed below the protruded portion. The cap is divided into at least two caps for smooth assembling. 
   Preferably, a plurality of guide members formed from the center of the eccentric shaft along an outer circumferential direction are installed on the upper surface of the wash plate. The guide members may be made in the form of a spiral type. 
   Also, a plurality of guide members which form a concentric circle with respect to the center of the eccentric shaft may be installed on the upper surface of the wash plate. Preferably, the guide members have a section shape of waves. 
   Preferably, the upper surface of the wash plate has a height difference along the rotational direction. The vertical section of the wash plate may be made to have a construction in which a tangent slope with respect to the surface of the wash plate increases as it radially travels from the central portion to the circumferential portion. 
   Preferably, a textile caught preventing ring is installed at a lower circumference of said wash plate such that laundry is not caught between the lower side of the inner tub and the wash plate. 
   Preferably, the counterweight is at least partially inserted in the wash plate so as to match the height in the center of gravity of the counterweight with the height in the center of gravities of the eccentric shaft and the wash plate. 
   Preferably, a plurality of protruded portions are formed at the inner wall of the inner tub, so that the laundry is effectively washed between the wash plate and the protruded portions of the inner tub due to the orbiting movement of the wash plate. 
   In another aspect of the invention, the eccentric shaft is installed oblique by a predetermined angle. 
   Preferably, a flexible member is installed between the wash plate and the lower portion of the inner tub. 
   Preferably, the lower portion of the inner tub is made to have a sphere shape. 
   In another aspect of the invention, the movement converting unit includes a base of which one side of the lower portion is coupled with the wash shaft, and circumference is directly coupled with the wash plate with a bearing as a medium. 
   In another aspect of the present invention, a washing machine includes: a wash shaft installed perpendicularly at a lower center of an inner tub, and rotating by a rotational force transferred from a motor; and a wash plate directly coupled to the wash shaft, wherein the rotational center of the wash shaft and the rotational center of the wash plate are arranged so as not to accord with each other, and thus the rotational movement of the wash shaft is converted into the orbiting movement of the wash plate. 
   According to the aforementioned invention, it becomes possible to minimize tangle and damage of the laundry and save usage amount of the wash water. 
   It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
       FIG. 1  is a side view schematically showing a conventional washing machine; 
       FIG. 2  is a sectional view of a washing machine according to an embodiment of the present invention; 
       FIG. 3  is a perspective view of main portions of  FIG. 2 ; 
       FIGS. 4A and 4B  are plan view and side view of a self-rotation preventing member of a washing machine according to the present invention; 
       FIG. 5  is a plan view of an exemplary construction of the washing plate of  FIG. 2 ; 
       FIG. 6  is a plan view of another exemplary construction of the washing plate of  FIG. 2 ; 
       FIGS. 7A and 7B  are plan view and disassembled view of another exemplary construction of the washing plate of  FIG. 2 ; 
       FIG. 8  is a side view of another exemplary construction of the washing plate of  FIG. 2 ; 
       FIG. 9  is a sectional view of a washing machine according to another embodiment of the present invention; 
       FIG. 10  is a sectional view showing a modification of  FIG. 9 ; 
       FIG. 11  is a sectional view of a washing machine according to another embodiment of the present invention; 
       FIG. 12  is a plan view of  FIG. 11 ; 
       FIG. 13  is a sectional view of a washing machine according to another embodiment of the present invention; and 
       FIG. 14  is a plan view of  FIG. 12 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
   Referring to  FIGS. 2 and 3 , a washing machine according to one embodiment of the present invention will be described as follows. 
   The washing machine of the present invention is the same in the general construction as that of the conventional art. In other words, the washing machine of the present invention also includes an outer tub  3 , an inner tub  5 , a clutch assembly  11 , a solenoid  11   a , a motor  9  and the like. However, the washing machine of the present invention further includes a movement converting unit  100  for converting the simple rotational movement of the motor  9  (or wash shaft  13 ) to a whirl movement. 
   In other words, water stream in the conventional washing machine is generated by the simple rotational movement of the pulsator coupled to the wash shaft. However, in the present invention, it is only necessary that a wash plate for generating water stream is coupled to the wash shaft with the movement converting unit as a medium, and it gyrates to effectively transfer physical force such as beating, bending and stretching the laundry, into the laundry. 
   In more detail, a hollow dehydration shaft  15  is coupled to the inner tub  5 , and a wash shaft  13  that can be selectively coupled to the dehydration shaft  15  is installed inside the dehydration shaft  15 .  FIG. 2  shows that the wash shaft  13  is directly coupled to the motor  9  by using the outer rotor type motor  9 , but it is apparent that the present invention is not limited thereto. In other words, it is naturally possible to indirectly transfer the rotational force of the motor  9  using a pulley not directly coupling the wash shaft  13  to the motor  9 . 
   Meanwhile, the wash shaft  13  is protruded toward the inner center of the inner tub  5 , and the rotation of the wash shaft  13  is transferred to the wash plate  200  with the movement converting unit  100  as a medium. In other words, a base  110  having an eccentric shaft  112  is coupled to the wash shaft  13 , and the wash plate  200  is coupled to the eccentric shaft  112 . At this time, in order to correct eccentric weights of the eccentric shaft  112  and the wash plate  200  that are eccentric with respect to the wash shaft  13 , it is preferable that a counterweight  130  is installed at an opposite side to the eccentric shaft  112 . 
   Respective elements and coupling relations are in more detail described as follows. 
   The wash shaft  13  is coupled integrally with the base  110 , and preferably they are serration-coupled. 
   Meanwhile, the wash plate  200  is directly coupled to the eccentric shaft  112 , but it is preferable that a wash plate adaptor  120  is interposed between the eccentric shaft  112  of the base  110  and the wash plate  200 . This is because the use of the wash plate adaptor  120  enables to enhance the relative movement of the wash plate  200  and the base  100 , and the assembling capability of the products. 
   Also, it is preferable that a bearing  140  is installed between the wash plate adaptor  120  and the eccentric shaft  112  such that the wash plate  200  and the wash plate adaptor  120  can freely perform relative movement with respect to the eccentric shaft  112 . 
   At this time, below the bearing  140  is installed a sealer  142  for preventing the wash water from being in contact with the bearing  140  during the washing. 
   Also, the bearing  140  may be made in a structure in which the rotational force is transferred in one side direction. In this case, the wash plate  200  is rotatable only when the wash shaft  13  is rotated in one side direction, and the wash plate  200  cannot be rotatable when the wash shaft  13  is rotated in a reverse direction. By doing so, it is possible to allow the wash plate  200  to perform the rotation movement in one side direction and to perform both the orbiting movement and the rotation movement in the other side direction according to the rotational direction of the wash shaft  13 . 
   In more detail, in order for the wash plate  200  to deviate from the normal location to upward or downward direction, a protruded portion  112   a  having a relatively large diameter is installed below the eccentric shaft  112 . The sealer  142  is installed over the protruded portion  112   a , and the wash plate adaptor  120  and an assemblable additional cap  144  are installed. For the smooth assembling, the cap  144  is preferably divided into at least two. A thrust bearing (not shown) may be additionally installed over and/or below the protruded portion  112   a  so as to lower the friction between the protruded portion  112   a  and other member(s). 
   Meanwhile, in order to assemble the cap  144  at the lower portion of the wash plate adaptor  120 , it is preferable to form an assembling hole  116  at a circumference of the base  110 . Of course, the circumference of the base  110  may be partially cut instead of the assembling hole  116 . 
   Also, in order to fix the base  110  on the wash shaft  13 , it is preferable to form an assembling hole  122   a  at a circumference of the wash plate adaptor  120  or partially cut the base  110 . 
   Next, an assembling procedure of the wash shaft  13 , the base  110  and the wash plate adaptor  120  is described as follows. 
   First, the bearing  140  and the sealer  142  are assembled to the wash plate adaptor  120 . After that, the wash plate adaptor  120  is assembled to the base  110  and finally the cap  144  is assembled. At this time, as aforementioned, since the cap  14  is divided into at least two, one is arbitrarily assembled and then a bolt  118  is coupled through the assembling hole  116  of the base  110 . The coupled cap is rotated by an angle of about 180°, and then the remaining cap is assembled in the same way. 
   Once the base  110  and the wash plate adaptor  120  are assembled, the base  110  is coupled to the wash shaft  13 . The base  110  is coupled to the wash shaft  13  by a bolt  13   a . At this time, a tool for coupling the bolt enters into the assembling hole  122   a  formed at the wash plate adaptor  120 . 
   Meanwhile, as aforementioned, in order to correct the eccentric weight of the eccentric shaft  112  and the wash plate  200 , the counterweight  130  is preferably installed at the opposite location to the eccentric shaft  112 . The counterweight  130  should balance with the eccentric weight of the eccentric shaft  112  and the wash plate  200 . Also, it is preferable that the height of the gravity center of the eccentric shaft  112  and the wash plate  200  is approximately similar to the height of the gravity center of the counterweight  130  so as to balance with the height of the gravity center of the eccentric shaft and the wash plate. 
   The counterweight  130  may be formed integrally with the wash plate  200 , the wash plate adaptor  120  or the base  110 , but it is more preferable that the counterweight  130  is separately installed at the base  110  for the convenience of the assembling. In other words, it is preferable that the counterweight  130  is installed to be slightly inserted into an inner space of the wash plate  200  at a location of 180° from the eccentric shaft  112  round the wash shaft  13 . 
   Meanwhile, it is preferable that a caught preventing ring  250  is installed at the circumference of the wash plate  200  such that the laundry is caught between the wash plate  200  and the inner tub  5 . It is more preferable that the caught preventing ring  250  is made of member having a low friction characteristic. The caught preventing ring  250  is preferably installed at a lower circumference of the wash plate  200 . Alternatively, it is also possible to fabricate the inner lower surface of the inner tub  5  in a proper shape so as to minimize a gap between the wash plate  200  and the lower portion of the inner tub  5  according to the movement of the wash plate  200 . 
   Meanwhile, as shown in  FIG. 4 , a self-rotation preventing member  400  is installed between the wash plate  200  and the inner tub  5 , thereby capable of preventing the rotational movement of the wash plate  200  with respect to the center of the eccentric shaft  112  when the wash plate orbits. 
   The self-rotation preventing member  400  is operated in a similar principle to Oldham coupling. In other words, the self-rotation preventing member  400  has a protruded vertical guide  410  and a protruded horizontal guide  420 . The vertical guide  410  is inserted in a linear groove (not shown) formed on the upper surface of the inner tub  5 , and the horizontal guide  420  is inserted in a linear groove (not shown) formed at the lower surface of the wash plate  200 . By doing so, the self-preventing member  400  can be moved only in the upward and downward direction with respect to the inner tub  5 , and the wash plate  200  can be moved only in the left and right direction, so that the wash plate  200  does not self-rotate but freely orbits. 
   Meanwhile, a plurality of protruded portions (not shown) are formed at the inner wall of the inner tub  5 , so that the laundry is effectively washed between the wash plate  200  and the protruded portions of the inner tub  5  due to the orbiting movement of the wash plate  200 . 
   Next, the wash plate  200  is in detail described with reference to  FIGS. 3 ,  5  and  6 . In the drawings, reference numeral  01  represents a rotational center of the wash shaft, and numeral  02  represents a rotational center of the eccentric shaft, e.g., wash plate. 
   The wash plate  200  includes a boss part  210  placed at the center and coupled with the wash plate adaptor  120 , and a horizontal part  220  that is approximately flat and is formed extending toward the circumferential direction from the boss part  210 . A plurality of guide members  240  are installed at the horizontal part  220  of the wash plate  200 . As shown in  FIG. 3 , the guide members  240  are made in an upward protruded shape, and are radially installed in the circumferential direction from the center  02  of the eccentric shaft. And, as shown in  FIG. 5 , the plurality of radial-shaped guide members  240  may be installed in a spiral type. By doing so, it is possible to push or pull the laundry toward the center of the wash plate  200  or the circumferential portion by the forward and backward rotation of the wash shaft  13 . Also, as shown in  FIG. 6 , the guide members are made in a circle type, and they may be arranged to form a plurality of concentric circles about the center  02  of the eccentric shaft. 
   Meanwhile, it is preferable that the respective guide members  240  are varied in height as it travels from the central portion to the circumferential portion. For instance, by forming concave portions  242  at selected portions of the wash plate  200 , it is preferable to make the wash plate  200  in the form of waves. By doing so, when the laundry is radially moved, the wash plate serves as a washboard. 
   Meanwhile, as shown in  FIG. 7 , it may be intended that the upper surface of the wash plate has a height difference in the rotational direction. For instance, it is preferable that the upper surface of the wash plate  200  is made in the form of a sawtooth. By doing so, it is possible to induce vibration and fluctuation of the laundry in the upward and downward direction by the horizontal orbiting movement of the wash plate  200  and the rotational movement of the wash plate  200  with respect to the eccentric shaft  112 . 
   Also, as shown in  FIG. 8 , it is preferable that the vertical section passing through the center axis of the wash plate, i.e., the eccentric shaft  112  is made to have a construction in which a tangent slope with respect to the surface of the wash plate increases as it radially travels from the central portion to the circumferential portion, thereby allowing the circumferential portion to beat the laundry more positively. 
   Next, an operation of the washing machine according to the present invention is described as follows. 
   First, wash cycle is described as follows. As the wash shaft  13  is rotated by the rotation of the motor  9 , the base  110 , the eccentric shaft  112  and the counterweight  130  all integrally coupled with the wash shaft  13  are simultaneously rotated with the wash shaft  13  as a rotational shaft. At this time, the wash plate  200  is freely rotatable with respect to the eccentric shaft  112  by the bearing  140 . Accordingly, the wash plate  200  is orbited about the rotational center of the wash shaft  13 , and at the same time the wash plate  200  gradually rotates while sliding with the eccentric shaft  112  occurs due to the movement of the laundry. 
   Meanwhile, it is preferable that the wash shaft  13  repeats forward and backward rotation so as to prevent tangle of the laundry. As the wash shaft  13  is rotated in one side direction, the wash plate  200  orbits and at the same time is rotated in the orbiting direction with respect to the eccentric shaft  112 . And, as the wash shaft  13  is rotated in the opposite direction, the direction of the orbiting movement of the wash plate  200  is directly changed. As the orbiting movement continues, the direction of the rotational movement of the wash plate  200  is further changed into the direction of the orbiting movement of the wash plate  200 . 
   Meanwhile, the laundry is continuously moved from the center portion of the inner tub  5  to the side portion of the inner tub  5  regardless of the rotational direction of the wash shaft  13 . Also, by the shape of the upper surface of the wash plate  200 , the laundry vibrates in the upward and downward direction to be beaten, and is also compressed, bent and stretched between the side surface of the wash plate  200  and the inner sidewall of the inner tub  5 , thereby performing the washing. Imbalance of the eccentric shaft  112  and the wash plate  200  with respect to the wash shaft  13  during the washing is offset by the action of the counterweight  130 , so that vibration decreases. 
   In the dehydration cycle, as the solenoid is driven, the wash shaft  13  and the dehydration shaft  15  are integrally coupled with each other. Once the motor  9  is rotated, the wash shaft  13 , the dehydration shaft  15 , the wash plate  200  and the counterweight are integrally rotated, so that the dehydration is carried out. 
   As described above, according to the present invention, by the orbiting movement and the rotational movement of the wash plate  200 , the laundry in the inner tub  5  is continuously beaten, bent and stretched, so that the washing is carried out nearly without tangle and damage of the laundry. Also, the laundry is beaten by the guide members formed on the wash plate  200 , and radial fluctuation proceeding from the central portion of the lower portion of the inner tub  5  is continuously generated, so that tangle and damage of the laundry is remarkably reduced. 
   Referring to  FIG. 9 , a washing machine according to another embodiment of the present invention is described. 
   The present embodiment is the same in the whole construction as the previous embodiment, but the present embodiment has an eccentric shaft  112  obliquely installed by a predetermined angle (θ) such that an arbitrary point of the wash plate  200  is movable up and down. 
   In more detail, on a plane where the wash shaft  13  and the eccentric shaft  112  pass, an upper portion of the eccentric shaft  112  is sloped with respect to a lower portion of the eccentric shaft  112  toward a vertical direction passes through the wash shaft  113  or an opposite direction to the vertical direction, or toward a direction perforating the plane. By doing so, the wash plate  200  orbits about the wash shaft  13  during the washing and at the same time an arbitrary point on the surface of the wash plate  200  draws a trajectory of a vertical direction. 
   Meanwhile, a flexible member  500  is installed between the wash plate  200  and the lower portion of the inner tub  5 , thereby preventing the laundry from being caught between the wash plate  200  and the lower portion of the inner tub  5 . 
   Meanwhile, as shown in  FIG. 10 , it is preferable that the lower portion of the inner tub  5  has a partial surface shape of sphere. Since the wash plate  200  is moved round a central point  03  of the rotation where an extending line of the wash shaft meets with an extending line of the eccentric shaft, the lower portion  5   a  of the inner tub  5  preferably has a sphere shape with the central point  03  as the center of the sphere. By doing so, since the wash plate  200  is moved along the surface of the sphere shape during the washing, it can be prevented that the laundry is caught between the wash plate  200  and the bottom surface of the inner tub  5 . 
   Referring to  FIGS. 11 and 12 , a washing machine according to a further embodiment of the present invention is described. 
   The present embodiment is also the same in the whole construction as the previous embodiments, but the present embodiment is discriminated in that a pumping passage  300  and a pumping means  310  are additively installed to pump the wash water using the pumping means  310  during the washing and circulate the pumped wash water through the pumping passage  300 , thereby injecting the wash water from the upper portion of the inner tub  5  onto the laundry. 
   In more detail, the pumping passage  300  is formed at one side of the inner tub  5 . The pumping means  310  is installed below a base  110 . Preferably, the pumping means  310  is comprised of a plurality of blades. 
   While  FIG. 11  shows that the base  110  is made to have the same size as the inner diameter of the inner tub  5  and the pumping means  310  is installed below the base  110 , the present invention is not restricted thereto. In other words, any member may be used as the pumping means  310  if it is rotatable as the wash shaft  13  is rotated. 
   According to the present embodiment, the wash water is continuously pumped from the lower side of the inner tub  5  to the upper side of the inner tub  5  and the pumped wash water is injected onto the laundry during the wash cycle, thereby capable of saving the usage amount of the wash water. 
   Referring to  FIGS. 13 and 14 , a washing machine according to still another embodiment of the present invention is described. 
   The present embodiment is the same in principle as the previous embodiments, but is discriminated in that the eccentric shaft  112  is not separately formed at the base  110  but the base  110  holds the role of the eccentric shaft with the original role thereof so as to simplify the whole structure. In other words, the base  110  is formed larger relative to the wash shaft  13 , and the base  110  is coupled to the rotational shaft such that the center of the base  110  does not accord with the center of the wash shaft  13 . Also, on the circumference of the base  110  is coupled the washing plate  200  with the bearing  140  as a medium. By doing so, the center of gravity of the wash shaft  13  does not accord with the center of gravity of the base  110 . Accordingly, the counterweight  130  is installed at one side of the base  110 . Also, it is preferable that a caught preventing ring  250  is installed outside the base  110 . Since the operation of the present embodiment is the same as those of the previous embodiments, detail description thereof is omitted. 
   Meanwhile, the aforementioned embodiment shows and describes that the wash plate is coupled to the wash shaft with the movement converting unit as a medium. However, the present invention is not restricted thereto. In other words, it is also possible to directly couple the wash plate to the wash shaft. At this time, the center of gravity of the wash shaft is arranged not to accord with the center of gravity of the wash plate such that the wash plate orbits about the wash shaft. 
   As described previously, the washing machines according to the present invention have the following effects. 
   First, a simple rotational movement of motor (or wash shaft) is converted into a orbiting movement by a movement converting unit and thus omnibus impact including horizontal and vertical directional impact is applied to the laundry, thereby remarkably reducing tangle and damage of the laundry. Also, use of the movement converting unit basically excludes occurrence structure of friction or impact, so that low noise is possible. 
   Secondly, since the movement converting unit may be made in the form of a module, its assembling is simplified. Also, since the movement converting unit can be equipped without changing the construction of the conventional washing machine, it is possible to apply the washing method of the present invention to the conventional washing machine. 
   Thirdly, according to the present invention, the laundry is not dipped in the wash water and is washed by the re-circulation and injection of the wash water, so that usage amount of the wash water is reduced. 
   It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.