Patent Publication Number: US-10758097-B2

Title: Toilet lid device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2017-253960, filed on Dec. 28, 2017; the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments described herein relate generally to a toilet lid device. 
     BACKGROUND 
     Conventionally, a toilet lid device including a toilet seat and a toilet lid rotatably attached to a casing has been known. In a state of the toilet lid closed, a lower surface of the toilet lid covers an upper surface of the casing and an upper surface of the toilet seat. The toilet lid can suppress dust from accumulating on the upper surface of the casing and the upper surface of the toilet seat. 
     SUMMARY 
     According to the embodiment, a toilet lid device includes a casing, and a toilet seat and a toilet lid rotatably supported with respect to the casing. A lower surface of the toilet lid covers an upper surface of the toilet seat and an upper surface of the casing in a state of the toilet lid closed. The lower surface of the toilet lid has a first lower surface parallel to the upper surface of the toilet seat and a second lower surface parallel to the upper surface of the casing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating a toilet lid device according to an embodiment; 
         FIG. 2A  and  FIG. 2B  are a perspective view and a side view illustrating a toilet lid of the toilet lid device according to the embodiment; 
         FIG. 3A  to  FIG. 3D  are a rear view, a plan view, a right side view, and a left side view, respectively, illustrating a casing of the toilet lid device according to the embodiment; 
         FIG. 4A  and  FIG. 4B  are a side view and a cross sectional view illustrating the toilet lid device according to the embodiment; 
         FIG. 5  is a cross sectional view illustrating a portion of the toilet lid device according to the embodiment; 
         FIG. 6  is a cross sectional view illustrating a portion of the toilet lid device according to the embodiment; 
         FIG. 7  is a plan view illustrating a portion of the toilet lid device according to the embodiment; 
         FIG. 8  is a perspective view illustrating the toilet lid device according to the embodiment; 
         FIG. 9  is a side view illustrating a portion of the toilet lid device according to the embodiment; and 
         FIG. 10  is a plan view illustrating a portion of the toilet lid device according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The first invention relates to a toilet device. The toilet lid device includes a casing, and a toilet seat and a toilet lid rotatably supported with respect to the casing. A lower surface of the toile lid covers an upper surface of the toilet seat and an upper surface of the casing in a state of the toilet lid closed. The lower surface of the toilet lid has a first lower surface parallel to the upper surface of the toilet seat and a second lower surface parallel to the upper surface of the casing. 
     According to the toilet lid device, since the first lower surface is parallel to the upper surface of the toilet seat, and the second lower surface is parallel to the upper surface of the casing, the lower surface of the toilet lid can be uniformly close to the upper surface of the toilet seat, and the lower surface of the toilet lid can be uniformly close to the upper surface of the casing. For that reason, even if the closed toilet lid deflects at any position, an inner surface of the toilet lid abuts immediately with the upper surface of the toilet seat or the upper surface of the casing, and the toilet lid is supported from downward. That is, a load applied to the closed toilet lid is easily supported by the entire upper surface of the toilet seat and the entire upper surface of the casing, and damage of the toilet lid due to the deflection can be suppressed. 
     The second invention is the toilet lid device in the first invention, further comprising a toilet seat heater provided inside the toilet seat, the toilet seat heater warming the upper surface of the toilet seat. 
     According to the toilet lid device, since the first lower surface of the toilet lid is parallel to the upper surface of the toilet seat, a long distance portion between the upper surface of the toilet seat and the lower surface of the toilet lid can be suppressed from being generated. Thereby, warm air of the toilet seat heater can be suppressed from escaping from the long distance portion between the toilet lid and the toilet seat. 
     Third invention is the toilet lid device in the first invention, wherein an upper surface of the toilet lid is parallel to the lower surface of the toilet lid. 
     In the case where the lower surface of the toilet lid is set to be parallel to the upper surface of the toilet seat and the upper surface of the casing, if the upper surface of the toilet lid is not parallel to the lower surface of the toilet lid, a thickness and a weight of the toilet lid increase, and usability for the user becomes bad. On the contrary, according to the toilet lid device, the toilet lid can be thin, and the usability for the user can be suppressed from becoming bad. 
     The fourth invention is the toilet lid device in the third invention, wherein the upper surface of the toilet seat is flush with the upper surface of the casing in the state of the toilet lid closed. 
     In the case where the lower surface of the toilet lid is parallel to each of the upper surface of the toilet seat and the upper surface of the casing, if there is a step between the upper surface of the toilet seat and the upper surface of the casing, it results in formation of the step on the lower surface of the toilet lid as well. In this case, the shape of the toilet lid becomes complex, and manufacturing may be difficult. On the contrary, according to the toilet lid device, since unevenness between the upper surface of the toilet seat and the upper surface of the casing is small, it can be suppressed that the shape of the toilet lid becomes complex. 
     The fifth invention is the toilet lid device in the fourth invention, wherein the toilet lid covers the entire upper surface of the casing in the state of the toilet lid closed. 
     According to the toilet lid device, since the toilet lid covers the entire upper surface of the casing in the state of the toilet lid closed, dust can be suppressed from accumulating on the casing. Also, the dust can also be suppressed from accumulating between the toilet seat and the casing. 
     The sixth invention is the toilet lid device in the fourth invention, wherein the toilet lid includes a first hinge portion and a second hinge portion, and is rotatably supported with respect to the casing in the first hinge portion and the second hinge portion, and each of the first hinge portion and the second hinge portion is disposed at a position separated from a left end and a right end of the casing between the left end and the right end of the casing. 
     According to the toilet lid device, since the first, second hinge portions are separated from the left end and the right end of the casing, a distance between the hinge portions can be shorten in comparison with the case where the first, second hinge portions are provided on the left end and the tight end of the casing. Thereby, the toilet lid can be suppressed from being damaged due to the twist of the toilet lid between the hinge portions. 
     The seventh invention is the toilet lid device in the first invention, wherein the toilet lid exposes a left side surface and a right side surface of the casing in the state of the toilet lid closed, and covers the upper surface of the casing from a right side end to a left side end of the upper surface of the casing. 
     According to the toilet lid device, since the toilet lid covers the upper surface of the casing from the left side end to the right side end in the state of the toilet lid closed, the dust can be suppressed from accumulating on the upper surface of the casing. Also, the left side surface and the right side surface of the casing are exposed from the toilet lid in the state of the toilet lid closed, and thus the left side surface and the right side surface of the casing are easy to be cleaned with the toilet lid closed. 
     Various embodiments will be described hereinafter with reference to the accompanying drawings. In the drawings, the same reference numbers are applied to the same elements and the detailed description will be omitted as appropriate. 
       FIG. 1  is a perspective view illustrating a toilet lid device according to an embodiment. 
     As shown in  FIG. 1 , a toilet lid device  100  according to the embodiment includes a casing  10 , a toilet seat  30  on which a user sits, and a toilet lid  50 . Each of the toilet seat  30  and the toilet lid  50  is rotatably supported with respect to the casing  10 . In other word, each of the toilet seat  30  and the toilet lid  50  is pivoted for opening and closing. A state of  FIG. 1  is a state of the toilet seat  30  closed (lowered state) and a state of the toilet lid  50  opened (raised). The toilet lid  50  covers upper surfaces of the casing  10  and the toilet seat  30  from upward (see  FIG. 5 ). 
     A body cleaning function portion or the like is installed inside the casing  10 , which realizes cleaning of a human body private part (“bottom” or the like) of the user sitting on the toilet seat  30 . For example, a control circuit or the like controlling a cleaning nozzle  70  or operation of the cleaning nozzle  70  is provided inside the casing  10 . When the user is sitting on the toilet seat  30 , the cleaning nozzle  70  discharges wash water toward the private part of the user in a state where the casing  10  is advanced from the inside to forward. The casing  10  may be provided appropriately with various mechanisms such as “a warm air drying unit”, “a deodorizing unit”, or “an indoor heating unit” which blows warm air against “a bottom” or the like of the user seating on the toilet seat to dry. 
     In the specification of the application, each of “upward”, “downward”, “forward”, “backward”, “left lateral”, and “right lateral” is a direction viewed from the user sitting on the toilet seat  30  with the back to the open toilet lid  50 . 
       FIG. 2A  and  FIG. 2B  are a perspective view and a side view illustrating a toilet lid of the toilet lid device according to the embodiment. 
       FIG. 2B  shows a state of the toilet lid  50  in a closed state viewed in the left lateral direction. 
     The toilet lid  50  is formed from, for example, a urea resin. The toilet lid  50  is, for example, symmetrical, and has a bent shape when viewed in the lateral direction. A main body of the toilet lid  50  is a bent single plate bending plate portion  51 . An edge portion  57  is provided on a periphery of the bending plate portion  51 . As shown in  FIG. 2B , the toilet lid  50  (a bending plate portion  51 ) has an upper surface  53 , and a lower surface  55  on an opposite side to the upper surface  53 . The upper surface  53  faces upward and the lower surface  55  faces downward in a state of the toilet lid  50  closed. That is, the lower surface  55  is a surface facing an upper surface of the casing  10  and the toilet seat  30 . The edge portion  57  has a shape protruding in a direction from the upper surface  53  toward the lower surface  55  in the periphery of the bending plate portion  51 . 
     As shown in  FIG. 2B , the lower surface  55  has a first lower surface  55   a  and a second lower surface  55   b . The first lower surface  55   a  is positioned on the forward side of the toilet lid  50 , and the second lower surface  55   b  is positioned on the backward side of the first lower surface  55   a  in the state of the toilet lid  50  closed. An extending direction of the second lower surface  55   b  crosses an extending direction of the first lower surface  55   a  when viewed in the lateral direction in correspondence to the bent shape of the bending plate portion  51 . For example, the first lower surface  55   a  is a portion extending generally in a horizontal direction, and the second lower surface  55   b  is a portion having a downward slope facing forward in the state of the toilet lid  50  closed. 
     Similarly, the upper surface  53  has a first upper surface  53   a  and a second upper surface  53   b . The first upper surface  53   a  is on the forward side and the second upper surface  53   b  is connected to the backward side in the state of the toilet lid  50  closed. The upper surface  53  of the toilet lid  50  is parallel to the lower surface  55  of the toilet lid  50 . More specifically, the first upper surface  53   a  is parallel to the first lower surface  55   a  and the second upper surface  53   b  is parallel to the second lower surface  55   b.    
     The toilet lid  50  includes a pair of hinge portions (a first hinge portion  61  and a second hinge portion  62 ) arranged in a left-right direction. The pair of hinge portions are positioned at a rear end of the toilet lid  50 , and provided on the second lower surface  55   b  in the state of the toilet lid  50  closed. The pair of hinge portions have a shape protruding in a direction from the upper surface  53  toward the lower surface  55 . The first hinge portion  61  is positioned near a left end of the toilet lid  50 , and the second hinge portion  62  is positioned near a right end of the toilet lid  50 . The pair of hinge portions are inside the left and right ends of the toilet lid  50  and are separated from the left and right ends of the toilet lid  50 . 
     The first hinge portion  61  and the second hinge portion  62  have a hole  61   h  and a hole  62   h  extending in the left-right direction, respectively. The holes  61   h ,  62   h  are engaged with a support portion described later. Thereby, the toilet lid  50  is rotatably pivoted at the first hinge portion  61  and the second hinge portion  62 . 
     Two abutment portions  59  are provided on the first lower surface  55   a . The abutment portions  59  are in abutment with the upper surface of the toilet seat  30  in the state of the toilet lid  50  closed. That is, the toilet lid  50  is supported at the pair of hinge portions and the abutment portions  59  in the state of the toilet lid  50  closed. A thickness (a height) of the abutment portions  59  is thinner than a thickness of the toilet lid  50 . For that reason, as shown in  FIG. 2B , the abutment portions  59  are not viewed when viewed in the lateral direction. 
       FIG. 3A  to  FIG. 3D  are a rear view, a plan view, a right side view, and a left side view, respectively, illustrating the casing of the toilet lid device according to the embodiment. 
       FIG. 3A  shows a state of the casing  10  viewed in the backward direction,  FIG. 3B  shows a state of the casing  10  viewed in the upward direction,  FIG. 3C  shows a state of the casing  10  in the right lateral direction, and  FIG. 3D  shows a state of the casing  10  viewed in the left lateral direction. The casing  10  is formed from, for example, a resin of polypropylene or the like. The casing  10  has a left side surface  11 , a right side surface  13 , an upper surface  15 , a toilet seat disposition surface  16 , and a rear surface  17 . 
     The upper surface  15  is a surface facing upward and not facing backward. In this example, the upper surface  15  is an inclined surface facing upward and forward. The toilet seat disposition surface  16  is provided forward the upper surface  15 , and is a surface where a rear portion of the toilet seat  30  in the closed state is disposed. That is, the rear portion of the toilet seat  30  is positioned right above the toilet seat disposition surface  16  along the toilet seat disposition surface  16  in the state of the toilet seat  30  closed. A step is formed between the upper surface  15  and the toilet seat disposition surface  16 , and the position of the toilet seat disposition surface  16  is low. The toilet seat disposition surface  16  is an inclined surface facing upward and forward. The upper surface  15  of the casing  10  is taken as a region where the toilet seat  30  in the closed state is not disposed. That is, the upper surface  15  is the region which is positioned upward the toilet seat disposition surface  16  and the step between the toilet seat disposition surface  16  and the upper surface  15 . 
     A first step portion  19   a  and a second step portion  19   b  are provided on a right end and a left end of the casing  10  between the upper surface  10  and the toilet seat disposition surface  16 . The first step portion  19   a  is a retreated portion of the left end of the upper surface  15 , and is exposed to the left lateral of the casing  10  as shown in  FIG. 3D . The second step portion  19   b  is a retreated portion of the right end of the upper surface  15 , and is exposed to the right lateral of the casing  10  as shown in  FIG. 3C . 
     A left rear end  32  (see  FIG. 1 ) of the toilet seat  30  is disposed on the step portion  19   a , and is supported by a support shaft  23   a  (see  FIG. 3D ) provided in the casing  10 . A right rear end  31  (see  FIG. 1 ) of the toilet seat  30  is disposed on the second step portion  19   b , and is supported by a support shaft  23   b  (see  FIG. 3D ) provided in the casing  10 . Thereby, the toilet seat  30  is rotatably pivoted. 
     The rear surface  17  is a surface facing backward. The rear surface  17  may be an inclined surface facing backward and upward. In this example, the rear surface  17  has a first rear surface  17   a  facing backward and upward and a second rear surface  17   b  extending downward from the first rear surface  17   a.    
     A pair of grooves (a first groove  21   a  and a second groove  21   b ) arranged in the left-right direction are provided in the casing  10 . The first groove  21   a  and the second groove  21   b  are portions of the upper surface  15  and the first rear surface  17   a , which are depressed downward. The first groove  21   a  and the second groove  21   b  are provided between the left side surface  11  and the right side surface  13 , and are separated from the left side surface  11  and the right side surface  13 . In other words, the first groove  21   a  and the second groove  21   b  are disposed inside the left-right ends of the casing  10 . That is, as shown in  FIG. 3C , the first groove  21   a  and the second groove  21   b  are not exposed to the right lateral of the casing  10  and not viewed in the right lateral direction because of being covered with the right side surface  13 . As shown in  FIG. 3D , the first groove  21   a  and the second groove  21   b  are not exposed to the left lateral and not viewed in the left lateral direction because of being covered with the left side surface  11 . 
     The first hinge portion  61  of the toilet lid  50  is disposed in the first groove  21   a . The second hinge portion  62  of the toilet lid  50  is disposed in the second groove  21   b.    
       FIG. 4A  and  FIG. 4B  are a side view and a cross sectional view illustrating the toilet lid device according to the embodiment. 
       FIG. 4A  shows a state of the toilet device  100  in the state of the toilet seat  30  closed and the toilet lid  50  closed viewed in the left lateral direction.  FIG. 4B  is a cross sectional view of  FIG. 4A , and shows a cross section passing through the center in the left-right direction of the toilet lid device  100  and being perpendicular to the left-right direction. 
     The toilet seat  30  is formed from a resin such as polypropylene, for example. The toilet seat  30  has an upper surface  35  facing the closed toilet lid  50 . The toilet seat  30  has a bent shape when viewed in the lateral direction as well as the toilet lid  50 . That is, the upper surface  35  of the toilet seat  30  has an upper surface  35   a  on the forward side and an upper surface  35   b  on the backward side, and an extending direction of the upper surface  35   b  when viewed in the lateral direction crosses an extending direction of the upper surface  35   a.    
     As shown in  FIG. 4A , the lower surface  55  of the toilet lid  50  covers the upper surface  35  of the toilet seat  30  and the upper surface  15  of the casing  10  from upward. More specifically, the first lower surface  55   a  of the toilet lid  50  covers the upper surface  35   a  of the toilet seat  30  from upward, the second lower surface  55   b  of the toilet lid  50  covers the upper surface  35   b  of the toilet seat  30  and the upper surface  15  of the casing  10  from upward. 
     The first lower surface  55   a  of the toilet lid  50  is parallel to the upper surface  35   a  of the toilet seat  30  in the state of the toilet lid  50  closed. The second lower surface  55   b  of the toilet lid  50  is parallel to the upper surface  15  of the casing  10  on the backward side of the toilet seat  30  in the state of the toilet lid  50  closed. 
     Thereby, the lower surface  55  of the toilet lid  50  can be uniformly closer to the upper surface  35  of the toilet seat  30 , and the lower surface  55  of the toilet lid  50  can be uniformly close to the upper surface  15  of the casing  10 . For that reason, even if the closed toilet lid  50  is deflected at any position, the lower surface  55  of the toilet lid  50  immediately abuts with the upper surface  35  of the toilet seat  30  or the upper surface  15  of the casing  10 , and the toilet lid  50  is supported from downward. That is, a load applied to the closed toilet lid  50  over the entire upper surface  35  of the toilet seat  30  and the upper surface  15  of the casing  10  is easy to be supported and the damage of the toilet lid  50  due to the deflection can be suppressed. 
     In the specification of the application, “parallel” includes not only strictly parallel but also generally parallel. That is, “parallel” includes not only the case where the distance between two surfaces is constant but also the case where the distance between two surfaces changes, for example, in a range of 5 millimeters (mm) or less. 
     For example, a distance L 1  between the upper surface  35   a  of the toilet seat  30  and the first lower surface  55   a  of the toilet lid  50  in a direction perpendicular to the upper surface  35   a  of the toilet seat  30  is not less than 5 mm and not more than 10 mm. For example, a distance L 2  between the upper surface  15  of the casing  10  and the second lower surface  55   b  of the toilet lid  50  is not less than 5 mm and not more than 10 mm. 
     As shown in  FIG. 4B , the second lower surface  55   b  of the toilet lid  50  is parallel to the upper surface  35   b  of the toilet seat  30  in the state of the toilet lid  50  closed. For example, a distance L 3  between the upper surface  35   b  of the toilet seat  30  and the second lower surface  55   b  of the toilet lid  50  along a direction perpendicular to the upper surface  35   b  of the toilet seat  30  is not less than 5 mm and not more than 10 mm. The distance L 1 , the distance L 2 , the distance L 3  are desired to be equal one another. 
     In the case where the first lower surface  55   a  of the toilet lid  50  is parallel to the upper surface  35   a  of the toilet seat  30  and the second lower surface  55   b  of the toilet lid  50  is parallel to the upper surface  15  of the casing  10 , if the upper surface  53  of the toilet lid  50  is not parallel to the lower surface  55  of the toilet lid  50 , a thickness and a weight of the toilet lid  50  increase, and there is a fear that opening and closing operation of the toilet lid  50  becomes uneasy and usability for the user becomes bad, and the toilet lid  50  becomes difficult to be formed. On the contrary, as described with respect to  FIG. 2 , in the embodiment, the upper surface  53  of the toilet lid  50  is parallel to the lower surface  55  of the toilet lid  50 . Thereby, the toilet lid  50  can be thin, the uneasiness of the opening and closing operation of the toilet lid  50  can be suppressed, and the usability for the user can be suppressed from becoming bad. Formability of the toilet lid  50  can be suppressed from decreasing. 
     In the case where the lower surface  55  of the toilet lid  50  is parallel to each of the upper surface  35  of the toilet seat  30  and the upper surface  15  of the casing  10 , if there is a step between the upper surface  35  of the toilet seat  30  and the upper surface  15  of the casing  10 , it results in formation of the step on the lower surface  55  of the toilet lid  50  as well. In this case, the shape of the toilet lid  50  becomes complex, and manufacturing may be difficult. The step is formed also on the upper surface  53  of the toilet lid  50  and cleanliness may deteriorate. On the contrary, in the embodiment, as shown in  FIG. 4A  and  FIG. 4B , the upper surface  35  (the upper surface  35   b ) of the toilet seat  30  is flush with the upper surface  15  of the casing  10 . Thereby, since unevenness between the upper surface  35  of the toilet seat  30  and the upper surface  15  of the casing  10  is small, it can be suppressed that the shape of the toilet lid  50  becomes complex and the cleanliness deteriorates due to the step. 
     The fact that the two surfaces are “flush with” means that a distance between the two surfaces is not less than 0 mm and not more than 3 mm. That is, “be flush with” may include not only strictly no step or gap between the two surfaces but also the case of existing a slight step or gap. 
     The toilet lid  50  covers the entire upper surface  15  of the casing  10  in the state of the toilet lid  50  closed. In other words, the lower surface  55  of the toilet lid  50  faces the entire upper surface  15  of the casing  10 . Thereby, dust can be suppressed from accumulating on the casing  10 . Also, the dust can also be suppressed from accumulating between the toilet seat  30  and the casing  10 . As shown in  FIG. 4B , a curved surface r 1  is provided between the upper surface  15  and the first rear surface  17   a  of the casing  10  in a cross section perpendicular to the left-right direction. The upper surface  15  does not include the curved surface r 1 , and for example, is a portion extending linearly. 
     As shown in  FIG. 4B , a toilet seat heater  37  is provided inside the toilet seat  30 . The toilet seat heater  37  includes, for example, a circular metal member provided along the circumference of the opening of the toilet seat  30 . The metal member of the toilet seat heater  37  is energized, and thus the toilet seat heater  37  warms the upper surface  35  of the toilet seat  30 . The toilet seat heater  37  may be based on, for example, a tubing heater, a sheathed heater, a halogen heater, a carbon heater or the like. The metal member is formed of, for example, aluminum, copper or the like. The shape of the metal member may be in various configurations such as a sheet configuration, a wire configuration, a mesh configuration or the like. 
     The heat of the toilet seat heater  37  is easy to escape to the outside from a long distance portion between the upper surface  35  of the toilet seat  30  and the lower surface  55  of the toilet lid  50  in the state of the toilet lid  50  closed. On the contrary, since the first lower surface  55   a  of the toilet lid  50  is parallel to the upper surface  35   a  of the toilet seat  30 , the long distance portion between the upper surface  35  of the toilet seat  30  and the lower surface of the toilet lid  50  can be suppressed from being generated. Thereby, the warm air of the toilet seat heater  37  can be suppressed from escaping to the outside from the long distance portion between the upper surface  35  of the toilet seat  30  and the lower surface of the toilet lid  50 . 
       FIG. 5  is a cross sectional view illustrating a portion of the toilet lid device according to the embodiment. 
       FIG. 5  shows the vicinity of the left end of the casing  10  and the toilet lid  50  in A-A cross section shown in  FIG. 4A . 
     A curved surface r 2  is provided between the upper surface  15  and the left side surface  11  of the casing  10 . Each of the upper surface  15  and the left side surface  11  does not include the curve surface r 2 , and is a portion extending linearly in the cross section perpendicular to a longitudinal direction. 
     A left end portion (the edge portion  57 ) of the toilet lid  50  extends to the outside (left side) from the left side surface  11  of the casing  10 . A lower end  57   s  of the edge portion  57  extends downward the upper surface  15 . A distance L 9  in a vertical direction between the lower end  57   s  of the edge portion  57  and the upper surface  15  is, for example, approximately not less than 1 mm and not more than 5 mm. 
     The toilet lid  50  covers a portion of the curved surface r 2 . That is, the portion of the edge portion  57  overlaps the portion of the curved surface r 2  in the left-right direction. On the other hand, the toilet lid  50  does not cover the left side surface  11  of the casing  10 . That is, the edge portion  57  does not overlap the left side surface  11  in the left-right direction. A distance L 4  in the vertical direction between the lower end  57   s  of the edge portion  57  and the left side surface  11  is, for example, approximately not less than 6 mm and not more than 10 mm. 
     It is much the same as the above for right ends of the toilet lid  50  and the casing  10 . That is, a curved surface r 3  is provided between the upper surface  15  and the right side surface  13  of the casing  10  (see  FIG. 3B ). Each of the upper surface  15  and the right side surface  13  does not include the curved surface r 3 , and is a portion extending linearly in the cross section perpendicular to a longitudinal direction. A right end portion of the toilet lid  50  extends to the outside (right side) from the right side surface  13  of the casing  10 . A portion of the edge portion  57  overlaps a portion of the curved surface r 3  in the left-right direction in the state of the toilet lid  50  closed. On the other hand, the edge portion  57  does not overlap the right side surface  13  in the left-right direction in the state of the toilet lid  50  closed. 
     In this way, the toilet lid  50  exposes the left side surface  11  and the right side surface  13  of the casing  10  in the state of the toilet lid  50  closed. Thereby, the left side surface  11  and the right side surface  13  of the casing  10  are easy to be cleaned with the toilet lid  50  closed. Since the toilet lid  50  covers the upper surface  15  of the casing  10  from a right side end  15   g  (see  FIG. 3B ) to a left side end  15   h  in the state of the toilet lid  50  closed, the dust can be suppressed from accumulating on the upper surface  15  of the casing  10 . 
       FIG. 6  is a cross sectional view illustrating a portion of the toilet lid device according to the embodiment. 
       FIG. 6  shows the vicinity of the left end of the toilet seat  30  and the toilet lid  50  in B-B cross section shown  FIG. 4A . 
     A curved surface r 4  is provided between the upper surface  35  and a left side surface  33  of the toilet seat  30 . Each of the upper surface  35  and the left side surface  33  does not include the curved surface r 4 , and is a portion extending linearly in the cross section perpendicular to the longitudinal direction. 
     The left end portion (the edge portion  57 ) of the toilet lid  50  extends to the outside (left side) from the left side surface  33  of the toilet seat  30 . The lower end  57   s  of the edge portion  57  extends downward the upper surface  35 . A distance L 5  in the vertical direction between the lower end  57   s  of the edge portion  57  and the upper surface  15  is, for example, approximately not less than 1 mm and not more than 5 mm. 
     The toilet lid  50  covers a portion of the curved surface r 4 . That is, a portion of the edge portion  57  overlaps the portion of the curved surface r 4  in the left-right direction. On the other hand, the toilet lid  50  does not cover the left side surface  33  of the toilet seat  30 . That is, the edge portion  57  does not overlap the left side surface  33  in the left-right direction. A distance L 6  in the vertical direction between the lower end  57   s  of the edge portion  57  and the left side surface  33  is, for example, not less than 6 mm and not more than 10 mm. 
     It is much the same as the above for the right ends of the toilet seat  30  and the toilet lid  50 . That is, a curved surface r 5  is provided (see  FIG. 1 ) between the upper surface  35  and the right side surface  34  of the toilet seat  30 . Each of the upper surface  35  and the right side surface  34  does not include the curved surface r 5 , and is a portion extending linearly in the cross section perpendicular to the longitudinal direction. The right end portion of the toilet lid  50  extends to the outside (right side) from the right side surface  34  of the toilet seat  30 . A portion of the edge portion  57  overlaps a portion of the curved surface r 5  in the left-right direction in the state of the toilet lid  50  closed. On the other hand, the edge portion  57  does not overlap the right side surface  34  in the left-right direction in the state of the toilet lid  50  closed. 
     In this way, the toilet lid  50  exposes the left side surface  33  and the right side surface  34  of the toilet seat  30  in the state of the toilet lid  50  closed. For example, the toilet lid  50  is thinner than the toilet seat  30  when viewed in the lateral direction. Also, the toilet lid  50  covers the upper surface  35  of the toilet seat  30  from a right side end  35   g  (see  FIG. 1 ) to a left side end  35   h  in the state of the toilet lid  50  closed. 
     If a lateral width of the toilet seat  30  is smaller than the casing  10 , a range of the casing  10  covered with the toilet seat  30  from upward becomes narrow. For that reason, for example, left-right end portions of the toilet seat disposition surface  16  of the casing  10  are exposed, and the dust may be easy to be accumulated on the exposed portion in the state of the toilet lid  50  opened. On the contrary, in the embodiment, the toilet lid  50  does not cover the left side surface  33  and the right side surface  34  of the toilet seat  30  in the state of the toilet lid  50  closed, and exposes the left side surface  33  and the right side surface  34  of the toilet seat  30 . Thereby, the lateral width of the toilet seat  30  can be large. Therefore, the range of the casing covered with the toilet seat  30  from upward can be broad, and the dust can be suppressed from accumulating on the casing  10 . The dust can also be suppressed from accumulating between the toilet seat  30  and the casing  10 . 
     If the left side surface  33  and the right side surface  34  of the toilet seat  30  are exposed in the state of the toilet lid  50  closed, there is a fear that the heat of the toilet seat heater  37  is easy to escape to the outside from the exposed left side surface  33  and the exposed right side surface  34 . On the contrary, if the first lower surface  55   a  of the toilet lid  50  is parallel to the upper surface  35   a  of the toilet seat  30 , the entire first lower surface  55   a  of the toilet lid  50  can be uniformly close to the toilet seat  30 . Thereby, the heat of the toilet seat heater  37  can be suppressed from escaping to the outside. Also, if the second lower surface  55   b  of the toilet lid  50  is parallel to the upper surface  35   b  of the toilet seat  30 , the entire second lower surface  55   b  of the toilet lid  50  can be uniformly close to the toilet seat  30 . Furthermore, the heat can be suppressed from escaping. 
       FIG. 7  is a plan view illustrating a portion of the toilet lid device according to the embodiment. 
       FIG. 7  shows a state of the upper surface  15  of the casing  10  viewed in the upward direction in the state of the toilet seat  30  closed and the toilet lid  50  opened as shown in  FIG. 1 . 
     As shown in  FIG. 7 , the toilet lid device  100  includes a pair of support portions (a first support portion  71  and a second support portion  72 ) arranged in the left-right direction. The first support portion  71  and the second support portion  72  rotatably support the toilet lid  50  with respect to the casing  10 . 
     At least a portion of the first support portion  71  is disposed in the first groove  21   a  of the casing  10 . The first hinge portion  61  is connected to the first support portion  71  in the first groove  21   a . At least a portion of the second support portion  72  is disposed in the second groove  21   b  of the casing  10 . The second hinge portion  62  is connected to the second support portion  72  in the second groove  21   b.    
     In this example, each of the first support portion  71  and the second support portion  72  is a shaft extending in the left-right direction, and protrudes from the inside of the casing  10 . The first hinge portion  71  is inserted into the hole  61   h  of the first hinge portion  61  described with respect to  FIG. 2A , and is engaged with the first hinge portion  61 . The second support portion  72  is inserted into the hole  62   h  of the second hinge portion  62 , and is engaged with the second hinge portion  62 . Thereby, the toilet lid  50  rotates (open/close) with rotation of the first support portion  71  and the second support portion  72 . 
     A buffer unit  80  housed in the casing  10  is provided in the first support portion  71 . The buffer unit  80  includes a shaft connected to the first support portion  71  and fluid (oil) or the like filled around the shaft therein, and functions as a dumper. A viscous force of the fluid is transferred to the toilet lid  50  via the first support portion  71 . Thereby, the buffer unit  80  operates a braking force in a reverse direction opposite to a closing direction of the toilet lid  50  on the toilet lid  50  by the viscous force when the toiled lid  50  is closed. 
     An assist unit  90  housed in the casing  10  is provided in the second support portion  72 . The assist unit  90  includes a shaft connected to the second support portion  72  and an elastic body (for example, coil spring) engaged with the shaft or the like therein. An elastic force of the elastic body is transferred to the toilet lid  50  via the second support portion  72 . Thereby, the assist unit  90  operates an urging force in opening direction on the toilet lid  50  by the elastic force when the toilet lid  50  is closed. The assist unit  90  urges the toilet lid  50  only in the opening direction of the toilet lid  50 . The buffer unit  80  also may be provided with the elastic body urging the toilet lid  50  in the opening direction of the toilet lid  50 . 
     For example, in the case where a twist force of the toilet lid is applied to the other hinge portion in a state where one hinge of the pair of hinges provided on the toilet lid  50  is fixed, if a distance between the hinge portions is long, there is a fear that the toilet lid is easy to be twisted and the toilet lid is damaged. On the contrary, in the embodiment, each of the first hinge portion  61  and the second hinge portion  62  is disposed at a position separated from the left side surface  11  and the right side surface  13  of the casing  10  between the left side surface  11  (left end) and the right sider surface  13  (right end) of the casing  10 . Thereby, in comparison with the case where the first hinge portion  61  and the second hinge portion  62  are provided on the left side surface  11  and the right side surface  13  of the casing  10 , the distance between the hinge portions can be shorten. Thereby, the damage due to the twist of the toilet lid  50  between the hinge portions can be suppressed. 
     As described above, the first groove  21   a  and the second groove  21   b  are disposed inside the left-right ends of the casing  10 . For that reason, each of the left side surface  11  and the right side surface  13  of the casing  10  does not include a step backward the rear end of the toilet seat  30 . More specifically, the left side surface  11  does not have the step backward the left rear end  32  of the closed toilet seat  30 . The right side surface  13  does not include a step backward the right rear end  31  of the closed toilet seat  30 . 
     Thereby, sanitary property of the left side surface  11  and the right side surface  13  of the casing  10  can be improved. For example, the dust can be suppressed from accumulating on the left side surface  11  and the right side surface  13  of the casing  10 . For example, wiping cleaning of the left side surface  11  and the right side surface  13  of the casing  10  becomes easy. Since the toilet lid  50  is supported at the first, second hinge portions  61 ,  62 , balance in the left-right direction can be improved in comparison with the case of single hinge portion. For example, the toilet lid  50  is hard to be twisted when the user holds the right rear end or the left rear end of the toilet lid  50  and rotates the toilet lid. 
     In the specification of the application, it is assumed that “not including a step” includes not only the case of strictly no step but also, for example, the state of no step larger than 3 mm, favorably 1 mm. For example, the side surface of the casing  10  may be formed of multiple members like the right side surface  13  shown in  FIG. 3C . At this time, surfaces of the multiple members are provided so as to be flush with each other on the side surface of the casing  10 . 
       FIG. 8  is a perspective view illustrating a portion of the toilet lid device according to the embodiment. 
       FIG. 8  shows a state of periphery of the first hinge portion  61  viewed in the backward direction in the state of the toilet lid  50  closed. 
     A restriction portion  25   a  and a recess  25   b  are provided on a lower surface  25  of the first groove  21   a . The restriction portion  25   a  is positioned outside the casing  10  from the recess  25   b . In other words, the restriction portion  25   a  is positioned between the left side surface  11  and the recess  25   b  in the left-right direction. The first hinge portion  61  has an abutment surface  61   a  exposed backward the casing  10  in the state of the toilet lid  50  closed. 
     The first hinge portion  61  is disposed upward the restriction portion  25   a , and is not disposed in the recess  25   b . The recess  25   b  is exposed on a side of the rear surface  17  of the casing  10 , and communicates with the inside of the first groove  21   a . Thereby, the inside of the first groove  21   a  can be cleaned from the recess  25   b , and the cleanliness can be improved. 
     A bottom surface of the recess  25   b  has a downward slope toward backward. Thereby, water which enters into the first groove  21   a  can be discharged from the recess  25   b  to the outside. 
       FIG. 9  is a side view illustrating a portion of the toilet lid device according to the embodiment. 
       FIG. 9  shows a state of a periphery of the first hinge portion  61  viewed in the left lateral direction in the state of the toilet lid  50  opened. 
     If the toilet lid  50  rotates in the opening direction, the abutment surface  61   a  of the first hinge portion  61  also rotates. The rotated abutment surface  61   a  abuts with the restriction portion  25   a  of the first groove  21   a . In this way, the restriction portion  25   a  restricts a movable range in the opening direction of the toilet lid  50 . In the specification of the application, the state of the toilet lid  50  opened means a state of the abutment surface  61   a  abutted with the restriction portion  25   a.    
     The first hinge portion  61  has an upper surface  61   b  facing upward in the state of the toilet lid  50  opened. The upper surface  61   b  is flush with the upper surface  15  of the casing  10  in the state of the toilet lid  50  opened. Thereby, since the unevenness between the upper surface  61   b  of the first hinge portion  61  and the upper surface  15  of the casing  10  is small, the cleanliness can be improved. For example, the wiping cleaning of the upper surface  15  of the casing  10  becomes easy. 
       FIG. 10  is a plan view illustrating a portion of the toilet lid device according to the embodiment. 
       FIG. 10  shows a state of the periphery of the first hinge portion  61  viewed in the upward direction in the state of the toilet lid  50  opened. 
     A distance L 7  is a distance between a forward end  61   c  of the first hinge portion  61  and a forward end  27   a  of the first groove  21   a  in the state of the toilet lid  50  opened. A distance L 8  is a distance between a lateral end  61   d  (left side end) of the first hinge portion  61  and a lateral end  27   b  (left side end) of the first groove  21   a  in the state of the toilet lid  50  opened. As shown in  FIG. 10 , the distance L 7  is longer than the distance L 8 . 
     In this way, a gap between the forward end  61   c  of the first hinge portion  61  and the forward end  27   a  of the first groove  21   a  is relatively broad. Thereby, a dust cloth or the like can be put into from between the forward end  61   c  of the first hinge portion  61  and the forward end  27   a  of the first groove  21   a  in the state of the toilet lid  50  opened. For that reason, the cleaning inside the first groove  21   a  becomes easy. 
     In the case where the dust cloth or the like is put into the first groove  21   a  from a gap between the lateral end  61   d  of the first hinge portion  61  and the lateral end  27   b  of the first groove  21   a , a force is applied to a front end side of the first support portion  71  (shaft), and the first support portion  71  may be damaged. On the contrary, if the dust cloth or the like is put into the first groove  21   a  from the gap between the forward end  61   c  of the first hinge portion  61  and the forward end  27   a  of the first groove  21   a , the first support portion  71  can be suppressed from being damaged. 
     The descriptions about  FIG. 8  to  FIG. 10  can also be applied to the shapes of the second groove  21   b  and the second hinge portion  62 . For example, the casing  10  is symmetrical with respect to the first groove  21   a  and the second groove  21   b . Also, for example, the toilet lid  50  is symmetrical with respect to the first hinge portion  61  and the second hinge portion  62 . That is, the second hinge portion  62  includes an abutment surface  62   a , an upper surface  62   b , a forward end  62   c , and a lateral end  62   d  (right side end) (see  FIG. 2A ). These are the same as the abutment surface  61   a , the upper surface  61   b , the forward end  61   c , and the lateral end  61   d  of the first hinge portion  61 , respectively. The second groove  21   b  includes a restriction portion  26   a , a recess  26   b , a forward end  28   a , and a lateral end  28   b  (right side end) (see  FIG. 3B ). These are the same as the restriction portion  25   a , the recess  25   b , the forward end  27   a , and the lateral end  27   b  of the first groove  21   a , respectively. 
     As shown in  FIG. 3B , the restriction portions  25   a ,  26   a  are provided outside from the recesses  25   b ,  26   b  in the left and right grooves. In other words, the recesses  25   b ,  26   b  are provided between the restriction portion  25   a  and the restriction portion  26   a . The left and right balance of the toilet lid  50  can be improved by supporting the toilet lid  50  by the restriction portions  25   a ,  26   a  provided outside in the state of the toilet lid  50  opened. For example, one position of the left end and the right end of the toilet lid  50  is uneasy to be shifted forward or backward from the other position. 
     Although the embodiments are described above with reference to the specific examples, the embodiments are not limited to these specific examples. That is, design modification appropriately made by a person skilled in the art in regard to the embodiments is within the scope of the embodiments to the extent that the features of the embodiments are included. The shape, the dimension, the material, the disposition, and the installation form or the like included in the toilet lid device are not limited to illustrations and can be changed appropriately. 
     The components included in the embodiments described above can be combined to the extent of technical feasibility and the combinations are included in the scope of the embodiments to the extent that the feature of the embodiments is included.