Patent Publication Number: US-7216654-B2

Title: Dishwasher

Description:
This application claims the benefit of Korean Application No. 10-2002-0074988 filed on Nov. 29, 2002, which is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a dishwasher having a steam discharger including a fan motor for forcibly discharging steam, and more particularly, to such a dishwasher in which the steam discharger is provided with a mechanically controllable intake port cover, which interoperates with the fan motor. 
     2. Discussion of the Related Art 
     Generally speaking, a dishwasher is provided with a heater for performing the drying of dishes and the like immediately following a washing step. Drying is accomplished by heating air to be circulated within a cavity where the dishes are placed by a user. As an inherent byproduct of drying wet dishes, the water is converted into steam, which is discharged from the cavity to facilitate the drying action. Thus, a general dishwasher is provided with a fan and fan motor for forcibly discharging the steam, which are provided as part of a steam discharger communicating between an upper point of the cavity and the exterior of the dishwasher. The steam discharger is typically installed within the dishwasher&#39;s door. 
     Referring to  FIG. 1 , illustrating a dishwasher according to a related art, a washtub  4  is formed as a substantially hexahedral cavity in which sliding rack  8  is mounted. The washtub  4  is installed in a body  2  having an open front where a hinged door  6  is provided to close the cavity. A steam discharger  30  is installed in an upper portion of the door  6 , to discharge steam generated by the drying of dishes and the like. 
     The steam discharger  30  is comprised of a fan housing  32  one end of which communicates with the cavity at a steam intake port  32   a  and the other end of which penetrates the outer surface of the door  6  at a steam exhaust port  32   b ; an intake port cover  36 , coupled to one end of a shaft  36   a , for selectively opening and closing the steam intake port; and an electromagnet  38 , disposed at the other end of the shaft, for controllably operating the intake port cover via the shaft through a hole  32   h  provided in the fan housing. Thus, the electromagnet  38  of the steam discharger  30  is installed on the exterior of the fan housing  32 . A fan motor (not shown) is installed in the fan housing  32  and is disposed proximate to the steam exhaust port  32   b , to draw steam from inside the washtub  4  and to discharge the steam from the dishwasher. 
     The electromagnet  38  is activated to operate the shaft  36   a , by way of an electromagnetic force applied to the shaft, to cause the intake port cover  36  to seal the cavity during washing and rinsing steps, by blocking the steam intake port  32   a  to reduce heat loss and noise as well as preventing the spraying water from entering the steam discharger. Then, upon performing the drying step, the electromagnet  38  is deactivated to retract the shaft  36   a  and thereby cause the intake port cover  36  to open the steam intake port  32   a  so that the steam may be discharged by driving the fan motor within the fan housing. 
     During operation, however, the steam discharger  30  tends to fail since the electromagnet  38  cannot be protected from the steam entering through the steam intake port  32   a . That is, while the electromagnet  38  is deactivated and the steam intake port  32   a  is open, the steam escapes through the hole  32   h  of the fan housing  32  to make contact with electromagnet&#39;s components, causing an accelerated corrosion of terminals and the like. As a result, the electromagnet of the above steam discharger, adopted for use in the dishwasher according to the related art, is subject to frequent malfunction, short-circuiting, and permanent damage. There may also be corrosive damage introduced to other conductive elements necessary for operating an electromagnet. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a dishwasher that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
     An object of the present invention, which has been devised to solve the foregoing problem, lies in providing a dishwasher having a steam discharger, in which an intake port cover for closing a steam intake port is mechanically operated. 
     It is another object of the present invention to provide a dishwasher having a steam discharger, which eliminates the use of an electromagnet for operating an intake port cover of the steam discharger. 
     It is another object of the present invention to provide a dishwasher having a steam discharger, which improves reliability of the dishwasher. 
     Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent to those having ordinary skill in the art upon examination of the following or may be learned from a practice of the invention. The objectives and other advantages of the invention will be realized and attained by the subject matter particularly pointed out in the specification and claims hereof as well as in the appended drawings. 
     To achieve these objects and other advantages in accordance with the present invention, as embodied and broadly described herein, there is provided a dishwasher having a cavity, where steam is created, enclosed in part by a side and a fan motor for driving a fan via a rotational shaft, each of which are installed at an upper point of the cavity side, for generating a suction force to discharge the steam from the cavity through the upper point of the cavity side via a steam discharger. The steam discharger comprises a fan housing, enclosing the fan motor and fan, for guiding the steam discharged by an operation of the fan motor, the fan housing having a steam intake port communicating with the cavity, a steam exhaust port penetrating the cavity side, and a through-hole disposed in opposition to the steam intake port; an intake port cover, movably installed within the fan housing, for opening and closing the steam intake port of the fan housing, the intake port cover having a central shaft extending through the through-hole of the fan housing; and coupling means, linking the rotational shaft of the fan motor and the central shaft of the intake port cover, for transferring the driving force of the fan motor to the intake port cover to selectively open and close the steam intake port of the fan housing. 
     It is to be understood that both the foregoing explanation and the following detailed description of the present invention are exemplary and illustrative 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 cross-sectional view of a dishwasher according to a related art; 
         FIG. 2  is a cross-sectional view of a dishwasher having a steam discharger according to the present invention; 
         FIG. 3  is a perspective view of a mechanism for controlling an intake port cover of the dishwasher shown in  FIG. 2 ; 
         FIG. 4  is a cross-sectional view of the mechanism of  FIG. 3 ; and 
         FIG. 5  is a cross-sectional view illustrating an operational status of the mechanism as shown in  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Reference will now be made in detail to the preferred embodiment of the present invention, examples of which are illustrated in the accompanying drawings. Throughout the drawings, like elements are indicated using the same or similar reference designations where possible. 
     A general dishwasher has a cavity, i.e., a washtub, where steam is created, which is enclosed in part by a side, i.e., a hinged door. The dishwasher according to the present invention is further provided with a fan motor for driving a fan via a rotational shaft. The fan motor, fan, and rotational shaft are each installed at an upper point of the hinged door, to generate a suction force and thereby discharge the steam from the washtub through the door via a steam discharger. The present invention is particularly directed towards the steam discharger of such a dishwasher. 
     Referring to  FIGS. 2–4 , a dishwasher according to the present invention comprises a steam discharger  80 , which is typically installed between the inner and outer surfaces of a hinged door  56  installed on a front side of a body  52  encasing a washtub  54  where dishes and the like are placed on a sliding rack  58  to be washed. The stream discharger  80  comprises a fan housing  82 , enclosing a fan motor assembly  84 , for guiding the steam discharged by an operation of the fan motor assembly, the fan housing having a steam intake port  82   a  communicating with the cavity of the washtub  54 , a steam exhaust port  82   b  penetrating the cavity side, and a through-hole  82   d  in opposition to the steam intake port; an intake port cover  86 , movably installed within the fan housing, for selectively opening and closing the steam intake port of the fan housing, the intake port cover having a central shaft  86   a  extending through the through-hole of the fan housing; and coupling means  90 , linking the rotational shaft of the fan motor and the central shaft of the intake port cover, for transferring the driving force of the fan motor to the intake port cover to selectively open and close the steam intake port of the fan housing. An operation of the coupling means  90  opens the steam intake port  82   a  during the performance of a drying step by the dishwasher and closes the steam intake port during the performance of washing and rinsing steps. 
     The fan motor assembly  84  is installed within an upper portion of the fan housing  82 , to be parallel with the intake port cover  86 , and includes a fan motor  84   c  for driving via a rotational shaft  84   b  and fan  84   a  to generate a suction force drawing air and steam from the steam intake port  82   a  and expelling the air and steam from the washtub  54  through the steam exhaust port  82   b . The steam intake port  82   a  of the fan housing  82  is substantially flush with the inner surface of the door  56 , and the steam exhaust port  82   b  of the fan housing preferably protrudes slightly from the outer surface of the door. 
     The intake port cover  86  is formed of a rubber based material to provide an airtight seal of the steam intake port  82   a . To assist the sealing action, an annular rib  82   c , protruding toward the intake port cover  86 , is provided to an inner circumference of the steam intake port  82   a.    
     The coupling means  90  comprises a spring  92 , installed on an outer circumference of the rotational shaft  84   b  of the fan motor  84   c , to be elastically supported by the fan motor; a push ring  94 , installed movably along the rotational shaft of the fan motor, for compressing the spring; a push member  96 , hinge-coupled with the rotational shaft of the fan motor, for pressing the push ring when the rotational shaft of the fan motor is driven; and a linking rod  98  having one end supported by the push ring, the other end coupled to a distal end of the central shaft  86   a  of the intake port cover  86 , and a leverage point hinge-coupled to the fan housing  82  so that when, the push ring compresses the spring, the intake port cover opens the steam intake port  82   a.    
     The push ring  94  includes a hollow body  94   a , fitted to the rotational shaft  84   b  of the fan motor  84   c , having one end abutting the spring  92 ; and an annular flange  94   b , formed on the other end of the hollow body, the annular flange providing a first surface to catch the end of the linking rod  98  and a second surface in contact with the push member  96 . 
     The push member  96  includes a skewed hollow shaft  96   a , disposed at a first predetermined angle with respect to the rotational shaft  84   b  of the fan motor  84   c  and hinge-coupled to the rotational shaft at a second predetermined angle so as to movably rotate against the rotational shaft, and a pair of pivoting arms  96   b  extending perpendicularly from the circumferential surface of the skewed hollow shaft. The inner diameter dimension of the skewed hollow shaft  96   a , which is greater than the outer diameter dimension of the rotational shaft  84   b  of the fan motor  84   c , depends on the second predetermined angle of the skewed hollow shaft. When the rotational shaft  84   b  rotates, a centrifugal force is created in the pivoting arms  96   b  of the skewed hollow shaft  96   a , so that the pivoting arms are brought perpendicular to the rotational shaft  84   b  of the fan motor  84   c . Hence, an inn er lip of the skewed hollow shaft  96   a  pushes against the second surface of the annular flange  94   b , to thereby compress the spring  92  and activate the linking rod  98 . 
     In the operation of the steam discharger of the present invention, the fan motor  84   c  is inactive (i.e., not driven) during the performance of washing and rinsing steps by the dishwasher. Thus, as shown in  FIG. 4 , the fan motor  84   c  is in stopped state, and the intake port cover  86  blocks the steam intake port  82   a . Upon initiating the dishwasher&#39;s drying step, the fan motor  84  is actuated to rotate the fan  84   a  to expel the steam from the washtub  54  via the fan housing  82 . In doing so, as shown in  FIG. 5 , the driving force of the fan motor  84   c  causes the intake port cover  86  to open the steam intake port  82   a  via the coupling means  90 . 
     In detail, as the fan motor  84   c  is actuated to rotate the rotational shaft  84   b , the skewed hollow shaft  96   a  is rotated to thereby create a centrifugal force acting on the pivoting arms  96   b . As the pivoting arms  96   b  spin, the centrifugal force forces the pivoting arms perpendicular with the rotational shaft  84   b  of the fan motor  84   c  and in turn forces the circumferential surface of the skewed hollow shaft  96   a  parallel with the rotational shaft so that the inner lip of the skewed hollow shaft  96   a  presses the push ring  94 , which compresses the spring  92 . Simultaneously, one end of the linking rod  98  is set in motion by the annular flange  94   b , so that the other end acts the central shaft  86   a  of the intake port cover  86  to open the steam intake port  82   a . Thus, by a forcible blowing force of the fan  84   a  driven by the fan motor  84   c  via the rotational shaft  84   b , the steam in the washtub  54  is sucked into the fan housing  82  via the steam intake port  82   a  to be expelled from the washtub through the steam exhaust port  82   b.    
     Accordingly, the steam discharger of a dishwasher according to the present invention mechanically transfers power from the rotational shaft of the fan motor to the intake port cover, such that the steam intake port is opened whenever the fan motor is driven, thereby obviating an electrical activating means such an electromagnet. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover such modifications and variations, provided they come within the scope of the appended claims and their equivalents.