Abstract:
Disclosed is a heater assembly for a washing machine having improved stability and reliability. The heater assembly includes a cavity formed at a bottom surface of a tub storing washing water, a heater disposed in the cavity and heating the washing water, and a cover provided to the bottom surface of the tub and configured to cover the cavity.

Description:
[0001]     This application claims the benefit of Korean Application Nos. P2004-46010; P2004-46011 and P2004-46012, three of which are filed on Jun. 21, 2004, which are hereby incorporated by reference as if fully set forth herein.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a washing machine, and more particularly a heater assembly installed in the washing machine to heat washing water.  
         [0004]     2. Discussion of the Related Art  
         [0005]     As well known, a washing using hot water enhances a washing efficiency, and for such reason, the hot water is generally supplied to the washing machine from an outside of the washing machine. However, recently, the heater is provided to the washing machine in order to directly heat the washing water.  
         [0006]     In most cases, the heater is mounted with brackets on a bottom of an inside of an outer tub which stores the washing water. The heater generates heat depending on washing conditions such as kind of laundry, for heating the water stored in the outer tub to a temperature proper for the washing. Then, the washing machine can wash the laundry appropriately by using the heated washing water.  
         [0007]     However, as described, since the heater is mounted on a bottom surface of the outer tub, it is required to disassemble not only a housing of the washing machine, but also an inner tub inside the outer tub and other related components, for an exchange or a maintenance of the heater. Consequently, the maintenance of the heater is difficult and requires much time. The heater is also installed in a cavity formed at the bottom of the outer tub. Accordingly, the cavity is different in a water pressure from the bottom surface of the outer tub, and thus the washing water could not be properly supplied to the inner tub from the outer tub. In addition, if the heater is overheated, elements near the heater could be damaged and a fire might be occurred. Further, as terminals of the heater project out of the outer tub, a short circuit and a fire thereby might be occurred.  
       SUMMARY OF THE INVENTION  
       [0008]     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.  
         [0009]     An object of the present invention is to provide a heater assembly of a washing machine having convenience in maintenance and stability and reliability in operation.  
         [0010]     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.  
         [0011]     To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the present invention provides a heater assembly for a washing machine comprising: a cavity formed at a bottom surface of a tub storing washing water; a heater disposed in the cavity and heating the washing water; and a cover provided to the bottom surface of the tub and configured to cover the cavity.  
         [0012]     The cover and the bottom surface of the tub are preferably positioned in a common surface. The cover includes an inlet configured to allow the washing water to flow into the cavity, and the inlet sinks with a predetermined depth from the cover. In addition, the cover includes an outlet configured to discharge the washing water from the cavity, and the outlet rises with a predetermined height from the cover.  
         [0013]     Preferably, the heater is configured to be detachable from the tub at an outside of the tub. The heater comprises a heating portion disposed in the cavity and generating heat, and terminals projecting out of the tub and electrically connected to the heating portion. The heater further comprises a sealing mechanism configured to seal the cavity. Additionally, the heater further comprises a pressing mechanism for pressing sealing members which seals an opening in the cavity.  
         [0014]     The heater assembly further comprises a sensing device installed in the cavity and detecting a temperature of the heater. The sensing device is configured to be detachable from the tub at an outside of the tub. For this reason, the sensing device is fitted into a bottom of the tub to be inserted into the cavity and is separated from the tub by being pulled at an outside of the tub. In addition, the heater assembly further comprises a clamp holding the heater in the cavity, and this clamp is configured to be separated from the tub together with the sensing device. Preferably, the clamp is fixed only to the sensing device.  
         [0015]     In addition, the heater assembly further comprises a cover protecting terminals of the heater. The cover comprises non-conducting material of electricity. Actually, the cover comprises first and second covers covering the terminals respectively, and further comprises an auxiliary cover covering a ground terminal of the heater. Further, the cover includes an inclined surface for allowing water to flow thereon.  
         [0016]     Alternatively, according to another aspect of the invention, the heater assembly for a washing machine comprises a cavity formed at a bottom surface of a tub storing washing water; a heater disposed in the cavity and heating the washing water; and a sensing device installed in the cavity and detecting a temperature of the heater.  
         [0017]     Alternatively, according to still another aspect of the invention, the heater assembly for a washing machine comprises a cavity formed at a bottom surface of a tub storing washing water; a heater disposed in the cavity and heating the washing water; and a cover installed to the tub and protecting terminals of the heater.  
         [0018]     The present invention mentioned above improves stability/reliability and convenience of maintenance in the heater assembly for the washing machine.  
         [0019]     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  
       [0020]     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:  
         [0021]      FIG. 1  is a sectional view showing a washing machine according to the present invention;  
         [0022]      FIG. 2  is a perspective view showing a heater assembly according to the present invention together with an outer tub;  
         [0023]      FIG. 3  is a plane view showing a bottom surface of an outer tub to which a heater assembly of the present invention is installed;  
         [0024]      FIG. 4  is a perspective view showing a bottom of an outer tub to which a heater assembly is installed;  
         [0025]      FIG. 5  is a partial enlarged perspective view showing a heater assembly according to the present invention;  
         [0026]      FIG. 6  is a perspective view showing a clamp in  FIG. 5 ;  
         [0027]      FIG. 7  is a perspective view showing a cover for a heater assembly according to the present invention;  
         [0028]      FIG. 8  is a perspective view showing a cover for terminals in a heater assembly according to the present invention; and  
         [0029]      FIG. 9  is a partial enlarged perspective view showing a heater assembly to which a cover of  FIG. 8  is installed. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. In describing the embodiments of the present invention, same parts will be given the same names and reference symbols, and iterative description of which will be omitted.  
         [0031]      FIG. 1  is a sectional view showing a washing machine according to the present invention, and  FIG. 2  is a perspective view showing a heater assembly according to the present invention together with an outer tub.  
         [0032]     Referring to  FIG. 1 , the washing machine of the present invention comprises a housing  10 , and an outer tub  20  and an inner tub  30  both installed inside the housing  10 .  
         [0033]     The housing  10  is configured to hold various components of the washing machine therein and to protect such components. The housing  10  includes a top cover  12  provided at a top portion of the washing machine and a door  13  provided at the top cover  2 . The top cover  12  has a control panel for operation by a user, and the laundry is put into and taken out of the washing machine through the door  13 .  
         [0034]     The outer tub  20  is elastically fastened to an inner surface of the housing  10 , and stores washing water for constant supply of washing water to the inner tub during washing. More particularly, as shown in  FIG. 2 , the outer tub  20  has a space  21  for storage of washing water therein and a pass through hole  23  formed at a central portion of a bottom surface  22 . A driving shaft is mounted through the pass through hole  23  and connected to the inner tub  30 . There are brackets  24  fitting dampers along an outer circumference of the outer tub  20  for elastic coupling of the outer tub  20  and the housing  10 .  
         [0035]     The inner tub  30  is rotatably mounted in the outer tub  20 . The inner tub  30  is supplied with the washing water from the outer tub  20 . The laundry is introduced into the inner tub  30 , and washed as the inner tub  30  rotates. The driving part  40  is disposed below both the outer tub  20  and the inner tub  30  and provides power to the inner tub  20  so as to be rotated. In general, the driving part  40  includes a motor and clutch and is coupled to the inner tub  30  by the driving shaft.  
         [0036]     In the washing machine described above, warm or hot washing water is required depending on kinds and status of the laundry during an operation of the washing machine, for which the washing machine is provided with a heater assembly for producing hot or warm washing water for itself. As shown in  FIG. 2 , this heater assembly is mounted to the outer tub  20  for heating washing water in the outer tub  20  to a desired temperature.  
         [0037]     Referring to  FIGS. 2 and 3 , the heater assembly basically comprises a cavity  100  in the bottom surface  22  of the outer tub  20  (hereinafter referred to as “a tub”) and a heater  200  disposed in the cavity  100 .  
         [0038]     The cavity  100  sinks with a predetermined depth from the bottom surface  22 , and an outlet  140  is formed at a bottom of such cavity  100  to discharge the washing water out of the washing machine. As shown in  FIG. 4 , an opening  150  is formed at the bottom of the tub  20  to communicate with the cavity  100 , and the heater  200  is inserted into the cavity through the opening  150 . A rib  160  is formed adjacent to the opening  150 , such that the water is prevented from reaching to terminals  250 . In addition, the opening  150  sink with a predetermined depth laterally from an outer surface of the tub  20 , and this is to restrain the water on the tub  20  from flowing toward the terminals  250 .  
         [0039]     The heater  200  basically serves to heat the washing water stored in the tub  20 . The heater  200  includes a heating portion  210  disposed in the cavity  100  and generating heat and the terminals  250  projecting out of the tub  20  and electrically connected to the heating portion  210  for providing the electricity thereto.  
         [0040]     The heater  200  also has a sealing mechanism configured to seal the cavity  100 , accurately the opening  150 . In this sealing mechanism, as shown in  FIG. 4 , a first sealing member  270  is attached to an outer surface of the cavity  100 , accurately an outer surface of the tub  20  in order to seal the opening  150 . A ground terminal  260  is provided to this first sealing member  270 . And, as shown in  FIG. 5 , a second sealing member  230  projects into the cavity  100  to close the opening  150 . The heater  200  extends passing through the first and second sealing member  270  and  230  as shown. The first sealing member  270  is formed larger than the opening  150  and made of rigid material. The second sealing member  230  is made of elastic material and is formed identical in size with or slightly smaller than the opening  150  so as to be forcedly fitted into the opening  150 . In addition, the heater  200  preferably includes a pressing mechanism configured to press the first and second sealing members  270  and  230 . In such pressing mechanism, a pressing plate  220  is installed to the heater to be in contact with the second sealing member  230 . Additionally, a bolt  240  projects out of the tub  20  passing through the pressing plate  220 , the second sealing member  230 , and the first sealing members  270  successively as shown in  FIG. 4 , and a nut  280  is fastened to the bolt  240 .  
         [0041]     In case of an installation of the heater  200 , the heating portion  210  is inserted in the opening  150  first, and then the second sealing member  230  is forcedly fitted into the opening  150  and the first sealing member  270  latches on the outer surface of the tub  20 . As the nut  280  proceeds with being fastened to the bolt  240 , the pressing plate  220  presses the second sealing member  230 . Therefore, the second sealing member  230  expands by such pressing and then completely seals the opening  150 . Simultaneously, the first sealing member  270  is closely attached to the tub  20 , and thus the heater  200  is strongly coupled to the tub  20 . Meanwhile, when the nut  280  is unfastened, the second sealing member  230  is restored. Accordingly, the heater  200  is easily separated from the tub  20  by pulling the heater  200  at an outside of the tub  20 . Consequently, due the sealing and pressing mechanisms, the heater  200  could be installed to or separated from the tub  20  at the outside, not the inside of the tub  20 , and thus it is not necessary for the an exchange and a repair of the heater  100  to separate the inner tub  20  and other related components from the washing machine. This makes maintenance of the heater  200  easy and convenient.  
         [0042]     More specifically, the heating portion  210  of the heater  200  is bent by a plurality of times so as to have a great heating surface in a limited space. Actually, the heating portion  210  comprises a pair of first extensions  211  extending parallel to each other and a pair of second extensions  212  extending respectively from the first extensions  211  in an opposite direction to the first extensions  211 , as shown in  FIG. 5 . And, the second extensions  212  are connected to each other.  
         [0043]     Referring to  FIGS. 5 and 6 , the clamp  300  is provided in the cavity  100  to hold the heating portion  210 . This clamp  300  prevents the heating portion  210  from being shaken by a flow of the washing water in the tub  20  or an impact given to the tub  20 .  
         [0044]     As particularly shown in  FIG. 6 , the clamp  300  has one or more curved portion  320 , and the heating portion  210  is inserted into the curved portion  320  to be tightly supported thereby. More specifically, the clamp  300  includes first and second curved portions  321  and  322  being opposite to each other and each having a curvature corresponding to a diameter of the heating portion  210 . The first and second curved portions  321  and  322  are connected to each other by a parallel portion  323 . These first and second curved portions  321  and  322  practically support the second extension  212  of the heating portion  210 . When the heater  200  is inserted into the cavity  100  through the opening  150 , the second extensions  212  are fitted into the curved portions  321  and  322  with being guided by such curved portions  321  and  322 , and thus the clamp  300  is caused to support the heater  200  entirely.  
         [0045]     Further, a sensing device  400  is installed to the bottom of the cavity  100  to be adjacent to the heater  200 . The sensing device  400  comprises a thermostat. The clamp  300  is fixed only to the sensing device  400  as shown in relevant drawings. More specifically, the clamp  300  has an end portion fixed to the sensing device  400  and informs the sensing device  400  of a temperature of the heating portion  210  by a heat transfer. For this reason, the clamp  300  is made of metal material having a good thermal conductivity and has a joining point  310  formed at the end portion thereof by a welding to an upper portion of the sensing device  400 . Accordingly, the heat of the heating portion  210  is transferred to the joining portion  310 , and the sensing device  400  detects the temperature of the heating portion  210  by using the transferred heat. If a detected temperature is below a predetermined proper temperature, the sensing device  400  has a controller of the washing machine operate the heater  200 . Further, if the detected temperature is the proper temperature or above, the sensing device  400  has the controller stop an operation of the heater  200 . Therefore, the sensing device  400  is configured to actively adjust the temperature of the heater  200 , and thus prevent an overheating of the heater  200 .  
         [0046]     The sensing device  400  is forcedly fitted to the bottom of the tub  20  so as to be inserted into the cavity  100 . More specifically, an opening (not shown) communicating with the cavity  100  is formed at the bottom of the tub  20 , and the sensing device  400  is fitted in such opening. In this case, a sealing member could be interposed between the opening and the sensing device  400  for a perfect sealing. Therefore, if the clamp  300  or the sensing device  400  needs to be exchanged or repaired, the heater  200  is firstly separated from the tub  20  by a method as mentioned above. Then, as a portion of the sensing device  400  exposed to the outside of the tub  20  is pulled downwardly, the sensing device  400  is separated from the tub  20 . Additionally, since the clamp  300  is coupled only with the sensing device  400  as described above, the clamp  300  is easily separated from the tub  20  through the opening together with the sensing device  400 . Consequently, similar to the heater  200 , the clamp  300  and the sensing device  400  could be installed to or separated from the tub  20  at the outside, not the inside of the tub  20  for the convenient maintenance.  
         [0047]     Referring to  FIG. 7 , the heater assembly according to the present invention further includes a cover  600  covering the cavity  100 . Also, at least one boss  130  is formed at the cavity  100  or the bottom surface of the tub  20  adjacent to the cavity  100  (see  FIG. 5 ), and a hole  620  corresponding to the boss  130  is formed at the cover  600 . Therefore, the cover  600  is coupled to the boss  130  by using a fastening member.  
         [0048]     The cover  600  and the bottom surface of the tub  20  are positioned in a common plane, and this compensates for a difference in height between the bottom surface of the cavity  100  and the bottom surface of the tub  20 . Accordingly, as the cover  600  reduces a difference of water pressure in the tub  20  caused by the difference in the height, the washing water is allowed to be smoothly supplied to the inner tub  30  from the tub, i.e. the outer tub  20 . In addition, the laundry is not in contact with the heater  200  by the cover  600 . Accordingly, the cover  600  prevents a fire or a damage of the laundry. For this reason, the cover  600  is made of nonflammable material, preferably stainless steel which is light and has proper strength.  
         [0049]     Additionally, the cover  600  includes an inlet  610  allowing the stored washing water to flow into the cavity  100 . An outlet  620  is formed apart from the inlet  610  to discharge the washing water from the cavity  100 . The inlet  610  sinks with a predetermined depth from the cover  600 , and a portion around the inlet  610  is inclined downwardly. Therefore, the washing water is guided by the inlet  610  so as to easily flow into the cavity  100 . Further, the outlet  620  rises with a predetermined height from the cover, and causes the washing water in the cavity  100  to easily flow to tub  20 . Accordingly, even though the cover  600  is installed to the tub, the washing water smoothly flows in or out of the cavity  100  through the inlet  610  and the outlet  620 , so as to be properly heated by the heater  200 .  
         [0050]     Meanwhile, as explained above, the terminals  250  project out of the tub  20 , while the heating portion  210  is disposed in the tub  20  (i.e. the cavity  100 ). If the washing water overflows the tub  20 , such washing water flows along the outer surface of the tub  20  and reaches the terminals  250  and the ground terminal  260  such that the fire or the short circuit occurs. Therefore, as shown in  FIGS. 8 and 9 , the heater assembly of the present invention further includes a cover  700  protecting the terminals  250  and  260  in order for the water not to reach the terminals  250  and  260 .  
         [0051]     The cover  700  comprises first and second covers  710  surrounding the terminals  250 , and a rib  730  connects the first and second covers  710 . An auxiliary cover  720  is further formed at the rib  730  to surround the ground terminal  260 . A bolt cover  740  is formed at the rib  730  to surround the bolt  240  (see  FIG. 4 ), and a hole  741  through which an end of the bolt  240  passes is formed at a center of the bolt cover  740 . In addition, the first and second covers  710  and  720  each include an inclined surface extending from an upper portion to a lower portion thereof. Accordingly, since the water inherently flows along such inclined surfaces, the covers  710  and  720  completely prevents the terminals  250  from being in contact with the water. Further, as the covers  710  and  720  cover the terminals  250  and the ground terminal  260 , these covers  710  and  720  are very likely to be in contact with the terminals  250  and  260 . Therefore, it is preferable that the cover  700  is made of non-conducting material of electricity such as plastic.  
         [0052]     In order to couple the cover  700  to the tub  20 , the covers  710  and  720  are disposed to cover the corresponding terminals  250  and  260 , and the end of the bolt  240  projects through the hole  741 . Then, an additional nut is fastened to the bolt  240  so as to attach the cover  700  to the outer surface of the tub  20 .  
         [0053]     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 inventions. 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.