Patent Publication Number: US-2011056942-A1

Title: Waste Disposal Apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to waste disposal apparatuses for disposing of waste materials such as soiled diapers. 
     2. Description of the Background Art 
     Japanese Patent Publication No. 2002-502784 of unexamined applications discloses a technique relating to waste disposal apparatuses for disposing of waste materials such as soiled diapers. 
     A waste disposal apparatus described in Japanese Patent Publication No. 2002-502784 of unexamined applications includes a cylindrical film having its one end closed, and a waste accommodating main body for receiving a waste material placed in the film, together with the film. The waste accommodating main body includes a lower part that is a hollow container having an opening at its upper end, a tubular upper part that is pivotally attached to the lower part by a hinge, a lid that is pivotally attached to the upper end of the upper part by a hinge so as to be able to open and close, and clamps for releasably locking the upper part and the lower part together, and for releasably locking the lid and the upper part together. The lid includes a rotatable cutter blade for cutting the film. 
     When placing a waste material into this waste disposal apparatus, the clamp for the lid is released to open the lid, and the waste material is placed in the film. When emptying the waste accommodating main body, the cutter blade is rotated to cut the film, the clamp is released to pivot open the upper part of the waste accommodating main body, and then waste materials stored in the waste accommodating main body are thrown out. 
     SUMMARY OF THE INVENTION 
     However, in such a conventional waste disposal apparatus as described in Japanese Patent Publication No. 2002-502784 of unexamined applications, the clamp for locking the upper part and the lower part of the waste accommodating main body together has a simple structure, and thus infants may accidentally release the clamp and open the upper part of the waste accommodating main body. The clamp for locking the lid and the upper part of the waste accommodating main body also has a simple structure, and infants may accidentally open the lid. 
     As described above, the conventional waste disposal apparatus has the cutter blade for cutting the film. Thus, infants can be injured if they accidentally open the upper part of the waste accommodating main body or the lid and put their hands into the waste accommodating main body. 
     The present invention was developed to solve the above problems, and it is an object of the present invention to provide a waste disposal apparatus for disposing of waste materials such as soiled diapers, which includes a lock mechanism that is prevented from being accidentally unlocked by infants and is capable of being easily locked and unlocked with one hand. 
     A waste disposal apparatus according to the present invention includes: a waste accommodating main body having an upper part and a lower part which are separably connected together, and having an opening at its upper end; and a lid connected to the waste accommodating main body so as to be able to open and close the opening of the waste accommodating main body; and a sealing mechanism, and a film accommodating portion that accommodates a film for storing a waste material, which are attached to the upper part of the waste accommodating main body; and a lid lock mechanism for locking the lid and the upper part of the waste accommodating main body together in a coupled state; and a main body lock mechanism for locking the upper part and the lower part of the waste accommodating main body together in a coupled state; and a lid unlock mechanism in which a direction of an operation of unlocking the lid lock mechanism is different from that of an operation of opening the lid; and a main body unlock mechanism in which a direction of an operation of unlocking the main body lock mechanism is different from that of an operation of opening the upper part of the waste accommodating main body. 
     According to the present invention, in order to open the lid or the upper part of the waste accommodating main body, the user needs to operate the lid unlock mechanism or the main body unlock mechanism in a specific direction to unlock the lid lock mechanism or the main body lock mechanism, and also needs to open the lid or the upper part of the waste accommodating main body in a specific direction different from that direction. This makes it very difficult for infants, who have neither an intent to open the lid or the upper part of the waste accommodating main body nor knowledge of how to open it, to open the lid or the upper part of the waste accommodating main body. This can prevent infants from accidentally opening the lid or the upper part of the waste accommodating main body. 
     As a preferred embodiment, each of the lid unlock mechanism and the main body unlock mechanism may include an unlock operation portion and an opening operation portion within reach of fingers of operator&#39;s one hand. 
     According to the present invention, the unlock operation and the opening operation of the lid or the upper part of the waste accommodating main body can be easily performed with one hand. 
     As a preferred embodiment, the unlock operation portion may be a push button that is pressed by a finger. 
     According to the present invention, since the unlock operation portion is a push button, the user can easily figure out how to operate the unlock operation portion, and can easily operate the unlock operation portion. 
     As a preferred embodiment, the opening operation portion may be a recess or a protrusion which is held by a finger. 
     The lid may be pivotally connected at its one end to the upper part of the waste accommodating main body by a hinge, and the lid lock mechanism and the lid unlock mechanism may be provided at the other end of the lid, which is located on a side opposite to the hinge. 
     The upper part of the waste accommodating main body may be pivotally connected at its one end to the lower part of the waste accommodating main body by a hinge, and the main body lock mechanism and the main body unlock mechanism may be provided at the other end of the upper part of the waste accommodating main body, which is located on a side opposite to the hinge. 
     According to the present invention, the lid or the upper part of the waste accommodating main body can be opened by unlocking the lid lock mechanism or the main body lock mechanism and pivoting the lid or the upper part of the waste accommodating main body about the hinge as a fulcrum. Moreover, the recess or the protrusion is provided so as to be held by a finger when performing the pivoting operation. Thus, the waste disposal apparatus of the present invention is advantageous in that the pivoting operation can be easily performed. 
     As a preferred embodiment, the hinge that connects the upper part and the lower part of the waste accommodating main body may be provided substantially in a middle of a vertical height of the waste disposal apparatus. 
     According to the present invention, when unlocking the main body lock mechanism to pivot open the upper part of the waste accommodating main body, the back face having the hinge in the upper part of the waste accommodating main body contacts the back face having the hinge in the lower part of the waste accommodating main body, whereby the pivoting movement is stopped, and at the same time, the upper end of the lid contacts the ground or the floor. 
     This prevents the waste disposal apparatus from falling down in the pivoting direction by a force caused by pivoting of the upper part of the waste accommodating main body, and also stabilizes the center of gravity of the waste disposal apparatus when the upper part of the waste accommodating main body is open. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an overall perspective view of a waste disposal apparatus according to an embodiment of the present invention. 
         FIG. 2  is a side cross section of the waste disposal apparatus of the embodiment. 
         FIG. 3  is a side cross section of the waste disposal apparatus of the embodiment. 
         FIG. 4  is an enlarged side cross section of a sealing mechanism of the embodiment in the state where a sealing door is closed. 
         FIG. 5  is an enlarged side cross section of the sealing mechanism of the embodiment in the state where the sealing door is open. 
         FIG. 6A  is an enlarged side cross section showing nipping shapes of an L-shaped sealing door and an inverted L-shaped sealing door receiving portion of the embodiment when the L-shaped sealing door is open, and  FIG. 6B  is an enlarged side cross section showing the nipping shapes of the L-shaped sealing door and the inverted L-shaped sealing door receiving portion of the embodiment when the L-shaped sealing door is closed. 
         FIG. 7A  is an enlarged side cross section showing nipping shapes of a convex sealing door and a concave sealing door receiving portion of an embodiment of the present invention when the convex sealing door is open, and  FIG. 7B  is an enlarged side cross section showing the nipping shapes of the convex sealing door and the concave sealing door receiving portion of the embodiment when the convex sealing door is closed. 
         FIG. 8  is an exploded perspective view of a film accommodating portion of the embodiment. 
         FIG. 9  is an overall perspective view of a waste disposal apparatus according to the embodiment. 
         FIG. 10  is a perspective view of the waste disposal apparatus of the embodiment as viewed obliquely from behind. 
         FIG. 11  is an enlarged side cross section of a main body lock mechanism and a lid lock mechanism according to the embodiment. 
         FIG. 12  is a perspective view illustrating an operation of unlocking the main body lock mechanism according to the embodiment. 
         FIG. 13  is a side cross section showing a state where an upper part of a waste accommodating main body of the embodiment is pivoted. 
         FIG. 14  is a perspective view illustrating an operation of unlocking the lid lock mechanism according to the embodiment. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.  FIG. 1  is an overall perspective view of a waste disposal apparatus according to an embodiment of the present invention.  FIGS. 2-3  are side cross sections of the waste disposal apparatus of the embodiment.  FIG. 2  shows a state where a sealing door is closed, and  FIG. 3  shows a state where the sealing door is open. 
     A waste disposal apparatus  11  includes: a waste inlet  16  for inserting a waste material D such as a soiled diaper therethrough; a cylindrical film  15  extending downward from the waste inlet  16  and having its lower end closed by a knot  26 ; a waste accommodating main body  13  for receiving the waste material D inserted through the waste inlet  16 , together with the film  15 ; and a lid  23  that covers the waste inlet  16  from above. 
     The long film  15  is attached to the waste inlet  16 . The film  15  extends downward so as to cover the opening of the waste inlet  16 . 
     The waste accommodating main body  13  is a hollow container for storing waste materials D that are placed in the film  15 , and is divided into a lower part  17  and an upper part  19 . The lower part  17  of the waste accommodating main body  13  has a bottom  17   b  at its lower end, and has an opening at its upper end. The upper part  19  of the waste accommodating main body  13  covers, at its lower end, the opening at the upper end of the lower part  17 , and has the waste inlet  16  at its upper end. 
     An open/close sealing mechanism  28  is provided inside the upper part  19  of the waste accommodating main body  13 . The sealing mechanism  28  nips the film  15  at a position between the waste inlet  16  and the stored waste material D to seal the stored waste material D. The sealing mechanism  28  has a sealing door  33  and a sealing door receiving portion  35 . 
     The sealing mechanism  28  will be described later. 
     When disposing of a waste material D, the user first opens the lid  23  to place the waste material D into the film  15  from the waste inlet  16 . Then, the user inserts his/her hand into the waste inlet  16 , and pushes the film  15  down together with the waste material D to open the sealing door  33 . The waste material D thus pushed down, together with the film  15 , passes between the opened sealing door  33  and the sealing door receiving portion  35 . The waste material D then drops downward along the film  15 , and is stored in the waste accommodating main body  13 . As soon as the user drops the waste material D to a position below the sealing door  33  and the sealing door receiving portion  35 , and removes his/her hand from the waste inlet  16 , the sealing door  33  closes to nip the film  15 . Since a new length of the film  15  is pulled out from the waste inlet  16 , the waste inlet  16  is always supplied with a new length of the film  15 . 
       FIG. 4  is an enlarged cross section of the sealing mechanism  28  of  FIG. 2  when the sealing door  33  is closed.  FIG. 5  is an enlarged cross section of the sealing mechanism  28  of  FIG. 3  when the sealing door  33  is open. 
     The waste disposal apparatus  11  contains the open/close sealing mechanism  28  that nips the film  15  at a position between the waste inlet  16  and the waste material D placed in the waste accommodating main body  13 , and seals the waste material D. 
     The sealing mechanism  28  has the sealing door  33  and the sealing door receiving portion  35 . Upon closing of the sealing door  33 , the sealing door  33  engages with the sealing door receiving portion  35  to nip the film  15  therebetween. 
     A nipping portion of the sealing door  33  has a contact surface  33   c  that contacts the sealing door receiving portion  35  when the sealing door  33  engages with the sealing door receiving portion  35 . A nipping portion of the sealing door receiving portion  35  has a contact surface  35   c  that contacts the sealing door  33  when the sealing door  33  engages with the sealing door receiving portion  35 . The contact surfaces  33   c ,  35   c  are shaped so as to mesh and engage with each other in the state where the sealing door  33  is closed. 
     The sealing door receiving portion  35  is attached and fixed inside the upper part  19  of the waste accommodating main body  13  so that the sealing door  33  covers and closes the waste inlet  16  from beneath in the state where the sealing door  33  is closed. 
     A guide rail  37  for guiding the sealing door  33  in opening and closing directions is attached and fixed to the inner wall of the upper part  19  of the waste accommodating main body  13 . The guide rail  37  is attached and fixed at a position below the sealing door receiving portion  35 , and the sealing door  33  slides along the guide rail  37 . 
     The sealing door  33  is biased toward the sealing door receiving portion  35 , and in a normal state, the sealing door  33  is closed in an engaged state with the sealing door receiving portion  35 . In the normal state, as shown in  FIG. 2 , the film  15  is nipped by the sealing door  33  and the sealing door receiving portion  35 . 
     If the user pushes the sealing door  33  down, the sealing door  33  slides in the opening direction, namely away from the sealing door receiving portion  35 . As shown in  FIG. 3 , when the sealing door  33  is opened, the nipped film  15  is released to allow the waste material D to be inserted into the waste accommodating main body  13 . 
     In the present embodiment, as shown in  FIGS. 4-5 , the side cross sectional shape of the contact surfaces  33   c ,  35   c , which is formed when the sealing door  33  is closed and engages with the sealing door receiving portion  35 , is a combination of an L shape formed in the sealing door  33  and an inverted L shape formed in the sealing door receiving portion  35 . 
       FIG. 6A  is an enlarged side cross section schematically showing nipping shapes of the L-shaped sealing door  33  and the inverted L-shaped sealing door receiving portion  35  of the present embodiment when the L-shaped sealing door  33  is open.  FIG. 6B  is an enlarged side cross section schematically showing the nipping shapes of the L-shaped sealing door  33  and the inverted L-shaped sealing door receiving portion  35  of the present embodiment when the L-shaped sealing door  33  is closed. 
     As shown in  FIGS. 6A-6B , the contact surface  33   c  of the sealing door  33  has flat surfaces  33   c   1 ,  33   c   2 ,  33   c   3 . The flat surface  33   c   1  crosses the upper surface of the sealing door  33  to form a right angled L-shaped corner. The flat surface  33   c   2  crosses the flat surface  33   c   1  to form a right angled L-shaped corner. The flat surface  33   c   3  crosses the flat surface  33   c   2  and the lower surface of the sealing door  33  to form a right angled L-shaped corner. 
     The contact surface  35   c  of the sealing door receiving portion  35  has flat surfaces  35   c   1 ,  35   c   2 ,  35   c   3 . The flat surface  35   c   1  contacts the flat surface  33   c   1  and is parallel to the flat surface  33   c   1 . The flat surface  35   c   2  contacts the flat surface  33   c   2 , and forms a right angled L-shaped corner with the flat surface  35   c   1 . The flat surface  35   c   3  contacts the flat surface  33   c   3 , and forms a right angled L-shaped corner with the flat surface  35   c   2 . 
     When the sealing door  33  slides in the direction shown by arrow in  FIG. 6A  from the open state of  FIG. 6A  to the closed state of  FIG. 6B  to nip the film  15 , the film  15  is bent at right angles at two L-shaped corners α 1 , α 2 . That is, an imaginary straight line, which connects an upper end β and a lower end γ of the nipped portion of the film  15  shown in  FIG. 6B , is bent substantially horizontally between the L-shaped corners α 1 , α 2 . 
     The waste material D placed in the lower end of the film  15  is pulled downward by its own weight due to the gravity. That is, the film  15  is continuously subjected to a downward tension by the waste material D as shown by white arrow in  FIG. 6B . 
     If the film  15  being subjected to such a tension is nipped as shown in  FIG. 6B , and is bent at right angles at the two L-shaped corners α 1 , α 2 , the film  15  is subjected to a higher tension at these L-shaped corners α 1 , α 2 . Thus, a remaining airflow path, which causes passing of odors in the related art described above, is closed at right angles, whereby odor sealing capability can be significantly increased. 
     Moreover, the film  15  need not be twisted upon every disposal of a waste material D, which can avoid the disadvantage that the maximum amount of waste that can be accommodated in the waste disposal apparatus  11  is reduced by the twists of the film  15 . 
     The L shape and the inverted L shape can be easily formed when mass producing the sealing door  33  and the sealing door receiving portion  35  by a die molding method. Thus, the waste disposal apparatus  11  of the present embodiment is advantageous in terms of mass production of the products. 
       FIGS. 7A-7B  show another embodiment of the sealing door  33  and the sealing door receiving portion  35 .  FIG. 7A  is an enlarged side cross section showing nipping shapes of a convex sealing door  33  and a concave sealing door receiving portion  35  of the present embodiment when the convex sealing door  33  is open.  FIG. 7B  is an enlarged side cross section showing the nipping shapes of the convex sealing door  33  and the concave sealing door receiving portion  35  of the present embodiment when the convex sealing door  33  is closed. 
     In the present embodiment, the side cross sectional shape of the nipping portions of the sealing door  33  and the sealing door receiving portion  35  is a combination of a convex shape formed in the sealing door  33 , and a concave shape formed in the sealing door receiving portion  35  so as to receive the convex shape. 
     More specifically, a contact surface  33   c  of the sealing door  33  has a ridge  133  having a convex cross section, and a contact surface  35   c  of the sealing door receiving portion  35  has a ridge groove  135  having a concave cross section. The ridge  133  protrudes in a direction parallel to the sliding direction of the sealing door  33 . 
     Thus, when the sealing door  33  slides in the closing direction to engage with the sealing door receiving portion  35 , the convex shape of the sealing door  33  engages with the concave shape of the sealing door receiving portion  35  without hindering the sliding movement. 
     As shown in  FIGS. 7A-7B , the contact surface  33   c  of the sealing door  33  is formed by surfaces  33   c   1  to  33   c   5 , and the contact surface  35   c  of the sealing door receiving portion  35  is formed by surfaces  35   c   1  to  35   c   5 . Of these surfaces  33   c   2  to  33   c   5 ,  35   c   1  to  35   c   5 , the surfaces  33   c   2 ,  33   c   4  and the surfaces  35   c   2 ,  35   c   4  are surfaces that extend substantially perpendicularly to an imaginary straight line connecting an upper end β and a lower end γ of the nipped portion of the film  15  shown in  FIG. 7B . 
     Thus, when the sealing door  33  slides in the direction shown by arrow in  FIG. 7A  from the open state of  FIG. 7A  to the closed state of  FIG. 7B  to nip the film  15 , the film  15  is bent at right angles at four L-shaped corners α 1  to α 4 . That is, the film  15  is bent substantially horizontally between the L-shaped corners α 1 , α 2 , and between the L-shaped corners α 3 , α 4 . 
     As described above with reference to  FIGS. 6A-6B , the film  15  is pulled in the direction shown by white arrow at the bent portions α 1 , α 2 , α 3 , α 4  by the weight of the waste material D. Thus, the film  15  is subjected to a high tension at the four L-shaped corners α 1 , α 2 , α 3 , α 4 , and a remaining air flow path formed inside of the film  15  is closed at right angles, whereby odors can be sealed more reliably. 
     Moreover, the film  15  need not be twisted upon every disposal of a waste material D, which can avoid the disadvantage that the maximum amount of waste that can be accommodated in the waste disposal apparatus  11  is reduced by the twists of the film  15 . 
     Furthermore, the concave and convex shapes can be easily formed when mass producing the sealing door  33  and the sealing door receiving portion  35  by a die molding method. Thus, the waste disposal apparatus  11  of the present embodiment is advantageous in terms of mass production of the products. 
     The waste disposal apparatus  11  further includes a spring  39  for continuously biasing the sealing door  33  toward the sealing door receiving portion  35 . The larger the biasing force of the spring  39  is, the more the force for nipping the film  15  can be increased, whereby the odor sealing capability can further be increased. 
       FIG. 8  is an exploded perspective view of a film accommodating portion  14 . The waste disposal apparatus  11  includes the film accommodating portion  14 , which forms the waste inlet  16  and also accommodates the film  15 . The film accommodating portion  14  is detachably attached to a film attachment portion  12  provided in an upper region of the upper part  19  of the waste accommodating main body  13 , and forms the outline of the waste inlet  16 . The film accommodating portion  14  has a cylindrical tubular core  27  extending downward from the waste inlet  16 , a tubular core flange  27   f  provided at the lower end of the tubular core  27 , and a film holding flange  29  that is fitted and fixed to the upper end of the tubular core  27 . 
     The film  15  is accordion folded in the axial direction of the tubular core  27 , and is coaxially inserted on the outer diameter side of the tubular core  27 . The film holding flange  29  is fitted and connected to the tubular core  27  so as to prevent the film  15  from coming off from the tubular core  27 . 
     That is, by the film holding flange  29  located at the upper end of the tubular core  27 , and the tubular core flange  27   f  located at the lower end of the tubular core  27 , the film  15  is compressed in the accordion folded state and accommodated in the space between the upper and lower ends in the axial direction of the tubular core  27 . 
     The film  15  is a consumable part of the film accommodating portion  14 . If the film  15  accommodated in the film accommodating portion  14  runs out, the user replaces the used film accommodating portion  14  in the film attachment portion  12  with a refill film accommodating portion  14 . 
     Preferably, the film accommodating portion  14  may be configured so that only the film  15  is replaced with a refill film when the film  15  accommodated in the film accommodating portion  14  runs out. 
     In the operation of placing the refill film accommodating portion  14  in the film attachment portion  12 , the user of the waste disposal apparatus  11  first pulls out an end of the film  15 , which is accommodated in the compressed state on the tubular core  27 , upward beyond the outer peripheral edge of the film holding flange  29  while keeping the lid  23  open. Then, the user ties a knot  26  at this end of the film  15  to close the film  15 . The user pushes the knot  26  down through the tubular core  27  to the bottom  17   b  while pulling the film  15  out of the film accommodating portion  14 . 
     By disposal of waste materials such as soiled diapers into the film  15 , the waste materials are accumulated in the film  15 , and the film  15  accordion folded on the outer diameter side of the tubular core  27  is pulled out in the downward direction upon each disposal. Thus, the user can successively dispose of waste materials into the waste accumulating main body  13 . 
     As shown in  FIGS. 1-3 , in the waste disposal apparatus  11  of the present embodiment, the film accommodating portion  14  is supported by the upper part  19  of the waste accommodating main body  13  so that the axial direction of the tubular core  27 , namely the opening direction of the waste inlet  16 , crosses a vertical line at a predetermined angle. Thus, the waste inlet  16  is provided in a tilted state. 
     Note that although not shown in the figures, the film accommodating portion  14  may be supported by the upper part  19  of the waste accommodating main body  13  so that the opening direction of the waste inlet  16  is horizontal. In this case, the axis O of the tubular core  27  extends horizontally. In this configuration as well, a tension can be applied to the nipped portion of the film. 
     As shown in  FIGS. 4-5 , the sealing door  33  has a substantially flat upper surface  34 . The upper surface  34  will be described in detail later. In the waste disposal apparatus  11  of the present embodiment, the sealing door  33  is supported by the upper part  19  of the waste accommodating main body  13  so that the upper surface  34  of the sealing door  33  is tilted at a predetermined angle corresponding to the tilted axial direction of the tubular core  27  and crossing a horizontal plane. The sealing door  33  advances and withdraws at the predetermined angle to and from the sealing door receiving portion  35 . An advancing/withdrawing direction S of the sealing door  33  is tilted at an angle different from that of the axial direction of the tubular core  27 . 
     More specifically, as shown in  FIG. 4 , the following expression (1) is satisfied, where θ 16  represents a tilt angle of the waste inlet  16  (the tubular core  27 ) with respect to a vertical line, and θ 33  represents a tilt angle of the advancing/withdrawing direction S of the sealing door  33  with respect to a vertical line. 
       0°&lt;θ 16 &lt;θ 33   (1)
 
     According to the present embodiment, the tilt angle θ 33  of the advancing/withdrawing direction S of the sealing door  33  is larger than the tilt angle θ 16  of the waste inlet  16 . Thus, as the sealing door  33  is withdrawn in the opening direction, the sealing door  33  can move away from the axis O of the tubular core  27 . When opened, the sealing door  33  can be sufficiently separated from the film  15 . Thus, the film  15  is opened wide when the sealing door  33  is opened, which enables the user to easily insert a waste material D into the waste accommodating main body  13 . 
     Note that although not shown in the figures, the sealing door  33  may be supported by the upper part  19  of the waste accommodating main body  13  so that the upper surface  34  of the sealing door  33  extends perpendicularly to the horizontal direction (θ 33 =90°). In this case, the sealing door  33  advances and withdraws horizontally. In this configuration as well, the sealing door  33  can be effectively separated from the film  15  when opened. 
     Mothers typically lay their children down on the floor to change diapers. Namely, mothers typically sit on the floor while changing diapers. According to the present embodiment, mothers can easily insert soiled diapers (waste materials) through the waste inlet  16  and open the sealing door  33  to place the soiled diapers into the waste accommodating main body  13  without standing up after changing diapers in a sitting posture. 
     According to the present embodiment, the film accommodating portion  14  is supported by the upper part  19  of the waste accommodating main body  13  so that the axial direction of the tubular core  27  crosses the vertical line at the predetermined angle. Moreover, the sealing door receiving portion  35  is positioned so that the nipping portions, which are formed by engagement between the sealing door  33  and the sealing door receiving portion  35  located below the film accommodating portion  14 , are provided in a lower region of the tilt of the lower surface of the tubular core flange  27   f.    
     Thus, the upper surface  34  of the sealing door  33  is substantially flat, but to be exact, a front part  34   f  of the upper surface  34  of the sealing door  33  is substantially flat, and a rear part  34   r  of the upper surface  34  of the sealing door  33  is gently curved so as to be tilted with respect to the front part  34   f.    
     Referring to  FIG. 4 , the film accommodating portion  14  is supported in a tilted state by the upper part  19  of the waste accommodating main body  13  so that the front side of the film accommodating portion  14  is located lower than the rear side thereof. Moreover, the sealing door  33  cooperates with the sealing door receiving portion  35  on the front side of the sealing door  33 , namely on the lower side of the tilt of the sealing door  33 , to nip the film  15 . In other words, when the sealing door  33  is in a closed state, the contact surfaces  33   c ,  35   c , each having an L-shaped cross section, are present between the film accommodating portion  14  and the front part  34   f  of the upper surface  34  of the sealing door  33 , but not between the film accommodating portion  14  and the rear part  34   r  of the upper surface  34  of the sealing door  33 . 
     Thus, when the sealing door  33  is in a closed state, the front part  34   f  of the upper surface  34 , which is adjacent to the nipping surface  33   c , is located below and away from the film accommodating portion  14 . 
     On the other hand, no shape for nipping the film  15  is provided on the rear side of the sealing door  33 . Thus, when the sealing door  33  is in a closed state, the rear part  34   r  of the upper surface  34  is located near the lower end of the film accommodating portion  14 . In this manner, the upper surface  34  of the sealing door  33  is formed by two different surfaces (the flat front part  34   f  and the tilted rear part  34   r ) in order to contact the sealing door receiving portion  35  to close the waste inlet  16  from beneath. 
     In the present embodiment, as shown in  FIG. 4 , the upper surface  34  of the sealing door  33  is formed so as to satisfy the following expression (2), where θ 34f  represents an angle of the front part  34   f  with respect to a horizontal plane, and θ 34r  represents an angle of the rear part  34   r  with respect to a horizontal plane. 
       0°≦θ 34f &lt;θ 34r   (2)
 
     Thus, by putting his/her hand on the rear part  34   r  of the upper surface  34  when pushing the sealing door  33  open to dispose of a waste material D, the user can efficiently transmit the pushing force to the sealing door  33 . Thus, the user can open the sealing door  33  with a smaller force. 
     Not that as a modification of the present embodiment, the rear part  34   r  of the upper surface  34  may be substantially perpendicular to the advancing/withdrawing direction S. According to this modification, the pushing force that is applied from the user&#39;s hand to the sealing door  33  can be applied to the spring  39  without being reduced. Thus, the user can push the sealing door  33  open with a small force. 
     In the present embodiment, as described above, the sealing door  33  engages with the sealing door receiving portion  35  on the front side of the sealing door  33 , namely on the lower side of the tilt of the sealing door  33 , to nip the film  15 . 
     The film  15 , which is accommodated in the film accommodating portion  14  so as to be able to be pulled out from the waste inlet  16 , passes vertically downward through the tubular core  27 , and is accommodated together with the waste material D in the lower part  17  of the waste accommodating main body  13 . Thus, the film  15  is pulled vertically downward by the weight of the waste material D placed in the film  15  due to the gravity. 
     The tubular core  27  is supported in a tilted state so that the front side of the tubular core  27  is located lower than the rear side thereof. Thus, provided that L 0  represents a diameter of the waste inlet  16 , and θ 0  represents a tilt angle of the waste inlet  16  with respect to the horizontal direction, the film  15  is naturally drawn toward the lower side of the tilt, namely toward the front side, at least by a distance L 0  (1−cos θ 0 ). 
     The film  15  is nipped by the sealing door  33  and the sealing door receiving portion  35  at a position on the lower side of the tilt to which the film  15  is naturally drawn. This facilitates nipping of the film  15  by the sealing mechanism  28 , whereby more efficient sealing for blocking passing of odors can be expected. 
     The operation of opening the waste accommodating main body  13  will be described below. 
       FIG. 9  is an overall perspective view of a main body lock mechanism  25  and a lid lock mechanism  24  of the present embodiment.  FIG. 10  is an overall perspective view of the waste disposal apparatus  11  of the present embodiment as viewed obliquely from behind.  FIG. 11  is an enlarged side cross section of the main body lock mechanism  25  and the lid lock mechanism  24 . 
     When the waste disposal apparatus  11  is used normally, the upper part  19  and the lower part  17  of the waste accommodating main body  13  are closed so that the upper part  19  covers at its lower end a main body opening  17   h  located at the upper end of the lower part  17 . The film attachment portion  12  is provided in an upper region of the upper part  19  of the waste accommodating main body  13 , and the film accommodating portion  14  is attached to the film attachment portion  12 . 
     A main body hinge  31  is provided on the back face of the waste accommodating main body  13 . The main body hinge  31  is provided substantially in the middle of the vertical height of the waste disposal apparatus  11 . The upper part  19  of the waste accommodating main body  13  is pivotally attached to the lower part  17  thereof by the main body hinge  31 , and is pivotable about the main body hinge  31  as a fulcrum. As the upper part  19  of the waste accommodating main body  13  is pivoted, the main body opening  17   h  at the upper end of the lower part  17  is open to the outside. 
     The main body lock mechanism  25  and a main body unlock mechanism are provided on the front face of the waste accommodating main body  13 . When being locked, the main body lock mechanism  25  prevents pivoting of the upper part  19  in the state where the upper part  19  covers the lower part  17 , namely in the state where the upper part  19  closes the lower part  17 . The main body unlock mechanism is a mechanism for unlocking the main body lock mechanism  25 . 
     The main body lock mechanism  25  has a columnar main body push button  21 , and a push button receiving hole  32  that is formed as a through hole in the upper part  19  of the waste accommodating main body  13  in order to latch and lock the main body push button  21 . 
     The main body push button  21  is formed in the upper end of a vertical flexible pillar portion  21   p . The lower end of the pillar portion  21   p  is connected to the upper end of the lower part  17  of the waste accommodating main body  13 . 
     The main body push button  21  is a column that protrudes in the outer diameter direction of pivoting of the upper part  19  of the waste accommodating main body  13 . A push button outer peripheral edge  21   g , which is an outer peripheral edge of the column, engages with the push button receiving hole  32  formed in the lower end of the upper part  19 , thereby preventing pivoting of the upper part  19 . 
     The main body unlock mechanism includes the main body push button  21  as an operation portion for unlocking the main body lock mechanism  25 , and an opening operation portion for placing a user&#39;s hand thereon to pivot open the upper part  19  of the waste accommodating main body  13  after unlocking the main body lock mechanism  25 . 
     The upper part  19  of the waste accommodating main body  13  has a handle  22  as the opening operation portion. The handle  22  is provided at the lower end of the front face of the upper part  19 , which is located on the side away from and opposite to the back face of the upper part  19  to which the main body hinge  31  is attached. The handle  22  is positioned near and below the main body push button  21 . 
     The main body push button  21  is disengaged from the push button receiving hole  32  and the main body lock mechanism  25  is unlocked only while the main body push button  21  is being pressed. If the user releases the main body push button  21 , the pillar portion  21   p  is restored to its original position, and the main body lock mechanism  25  is locked again. 
     When the waste accommodating main body  13  is filled with waste materials D, the user empties the waste accommodating main body  13  by unlocking the main body lock mechanism  25  and opening the upper part  19  of the waste accommodating main body  13 . 
       FIG. 12  is a perspective view illustrating the operation of unlocking the main body lock mechanism  25 . As shown in  FIG. 12 , the user places four fingers, namely fingers other than the thumb, of one hand on the handle  22  from beneath, and at the same time presses with the thumb the main body push button  21  located near and above the handle  22 , thereby unlocking the main body lock mechanism  25 . The user lifts the handle  22  while unlocking the main body lock mechanism  25 . Thus, the upper part  19  of the waste accommodating main body  13  is pivoted toward the back side, and the waste accommodating main body  13  is opened. 
       FIG. 13  is a side cross section showing the state where the upper part  19  of the waste accommodating main body  13  of the present embodiment has been fully pivoted. When emptying the waste accommodating main body  13  that is filled with waste materials D, as shown in  FIG. 13 , the user first fully opens the upper part  19  of the waste accommodating main body  13 , and cuts the film  15  with a film cutter  38 . Then, the user ties a knot to close the cut face of the film  15 , and removes the bag of the film  15  filled with the waste materials D from the waste accommodating main body  13  to throw the bag out. After emptying the waste accommodating main body  13 , the user places the upper part  19  of the waste accommodating main body  13  over the lower part  17  thereof. Thus, the push button  21  engages with the push button receiving hole  32 , and the upper part  19  of the waste accommodating main body  13  is locked again. 
     In the waste disposal apparatus  11  of the present embodiment, the main body push button  21  is positioned near and above the handle  22  so that, when unlocking the main body lock mechanism  25  to pivot open the upper part  19  of the waste accommodating main body  13 , an adult user can press the main body push button  21  with other finger while supporting the handle  22  with any of the fingers of his/her one hand. 
     More specifically, the main body push button  21  is positioned on a path the thumb is ergonomically most likely to follow naturally when the user places the other four fingers on the handle  22  from beneath and closes his/her hand with the four fingers as a fulcrum. 
     This makes it easier and more comfortable for the user to unlock the main body lock mechanism  25  to pivot open the upper part  19  of the waste accommodating main body  13 . That is, the user can unlock the main body lock mechanism  25  with one hand according to his/her movement of naturally closing his/her hand. 
     In order to unlock the main body lock mechanism  25  to open the upper part  19  of the waste accommodating main body  13 , the user needs to press the main body push button  21  in the inner diameter direction that is substantially perpendicular to the pivoting direction of the upper part  19 , and to lift the handle  22  to pivot the upper part  19 . 
     Since such two operations in different directions are required, it is very difficult for infants, who have neither an intent to open the upper part  19  of the waste accommodating main body  13  nor knowledge of how to open it, to open the upper part  19 . This can prevent the infants from accidentally opening the upper part  19  of the waste accommodating main body  13  and being injured by touching the film cutter  38  for cutting the film  15 . 
     On the other hand, adults with intent to open the upper part  19  of the waste accommodating main body  13  can easily unlock the main body lock mechanism  25  and open the upper part  19  of the waste accommodating main body  13  with one hand. Thus, the waste disposal apparatus  11  is easy to handle when throwing out the waste materials D stored in the waste accommodating main body  13 . 
     The operation of opening the lid  23  will be described below. 
     The lid  23  is pivotally attached, at its end on the back side, to the upper end of the upper part  19  of the waste accommodating main body  13  by a lid hinge  30 , and the lid  23  is pivotable about the lid hinge  30  as a fulcrum. When the lid  23  is pivoted open, the waste inlet  16  is open to the outside as shown in  FIG. 1 . 
     As shown in  FIGS. 9 and 11 , the waste disposal apparatus  11  includes a lid lock mechanism  24 , and a lid unlock mechanism. When being locked, the lid lock mechanism  24  prevents pivoting of the lid  23  in the state where the lid  23  covers the waste inlet  16 , namely in the state where the lid  23  is closed. The lid unlock mechanism is a mechanism for unlocking the lid lock mechanism  24 . 
     The lid lock mechanism  24  has a lid push button  20 , and a lid push button receiving portion  36  provided in the upper part  19  of the waste accommodating main body  13 . The lid push button  20  is provided in the lower part of the front face of the lid  23 . A lid push button hook  20   h  is formed at the lower end of the lid push button  20 . The lid push button hook  20   h  moves integrally with the lid push button  20 . 
     The lid push button receiving portion  36  is formed at the upper end of the upper part  19  of the waste accommodating main body  13 . When the lid  23  is in a closed state, the lid push button receiving portion  36  engages with the lid push button hook  20   h.    
     The lid unlock mechanism includes the lid push button  20  as an operation portion for unlocking the lid lock mechanism  24 , and an opening operation portion for placing a user&#39;s hand thereon to pivot open the lid  23  after unlocking the lid lock mechanism  24 . 
     As the opening operation portion, the lid  23  has a lid handle  18  on the front face of the lid  23 . The lid handle  18  is positioned near and above the lid push button  20 . 
     When inserting a waste material through the waste inlet  16 , the user unlocks the lid lock mechanism  24  to open the lid  23 .  FIG. 14  is a perspective view illustrating the operation of unlocking the lid lock mechanism  24 . 
     When the user places four fingers, namely the fingers other than the thumb, of his/her one hand on the lid handle  18  from above, and presses the lid push button  20  by the thumb as shown in  FIG. 14 , the lid push button  20  together with the lid push button hook  20   h  moves in the pressing direction, and the lid push button hook  20   h  is disengaged from the lid push button receiving portion  36 , whereby the lid lock mechanism  24  is unlocked. The user lifts the lid handle  18  while pressing the lid push button  20  with the thumb and unlocking the lid lock mechanism  24 . Thus, the lid  23  is pivoted toward the back side, and the waste inlet  16  is opened. 
     After inserting a waste material through the waste inlet  16 , the user closes the lid  23 . Thus, the lid push button hook  20   h  is restored to its original position, and is engaged again with the lid push button receiving portion  36 , whereby the lid lock mechanism  24  is locked. 
     In the lid lock mechanism  24 , the lid push button hook  20   h  is disengaged from the lid push button receiving portion  36  only while the lid push button  20  is being pressed. That is, if the user releases the lid push button  20 , the lid lock mechanism  24  is locked again. 
     Thus, in order to unlock the lid lock mechanism  24  to open the lid  23 , it is necessary to press the lid push button  20  in the inner diameter direction that is substantially perpendicular to the pivoting direction of the lid  23 , and to lift the lid handle  18  to pivot the lid  23 . This makes it very difficult for infants, who have neither an intent to open the lid  23  nor knowledge of how to open it, to open the lid  23 . This can prevent the infants from accidentally opening the lid  23  and putting their hands into the waste disposal apparatus  11 . 
     However, adults with intent to open the lid  23  can easily unlock the lid lock mechanism  24  and open the lid  23  with one hand. Thus, the waste disposal apparatus  11  is easy to handle when inserting waste materials through the waste inlet  16 . 
     Moreover, according to the present embodiment, as shown in  FIG. 14 , the user can place the four fingers other than the thumb of his/her one hand on the lid handle  18  from above, and at the same time press the lid push button  20  located near and below the lid handle  18  with the thumb. That is, the operator can unlock the lid lock mechanism  24  according to his/her movement of naturally closing his/her hand. 
     More specifically, the lid push button  20  is positioned on a path the thumb is ergonomically most likely to follow naturally when the user places the other four fingers on the lid handle  18  from above and closes his/her hand with the four fingers as a fulcrum. This makes it easier and more comfortable for the user to unlock the lid lock mechanism  24  to pivot open the lid  23 . 
     Although the embodiments of the present invention are described above with reference to the drawings, the present invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiments within a scope that is the same as, or equivalent to the present invention. 
     The present invention provides waste disposal apparatuses having very safe lock mechanisms, and can be expected to be widely applied to industrial products such as, e.g., diaper disposal apparatuses.