Patent Publication Number: US-2022219892-A1

Title: Cassette with non-uniform liner cavity

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. Application No. 15/961,097, filed Apr. 24, 2018, which is a divisional of U.S. application Ser. No. 15/417,746, filed Jan. 27, 2017, which claims the benefit of priority of U.S. Provisional Application No. 62/288,069, filed Jan. 28, 2016, the contents of which applications are incorporated into the present application by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present disclosure relates to an apparatus for packaging disposable material or objects into a tubular flexible plastic film material in general, and to cassettes for providing the tubular flexible plastic film material in particular. 
     2. Background Information 
     Waste disposal devices that include a film-dispensing cassette are commonly used to throw away odorous waste, such as diapers and litter. In such waste disposal devices, the film-dispensing cassettes are supported at an opening of a bin and dispense a tubular film projecting into the inner cavity of the bin of the waste disposal device. The free end of the tubular film can be closed to define a bag-like structure. Often, the waste disposal device includes an internal mechanism that closes the bag shut (e.g., by clamping, twisting, etc.), thereby isolating the waste in the bag below the internal mechanism, and capturing the odors in the bag. 
     SUMMARY OF THE APPLICATION 
     According to an aspect of the present disclosure, a film-dispensing cassette for a waste disposal device is provided. The cassette has a variable geometry. The cassette has an inner cavity edge defining a central opening through which liner film is disposed to collect and hold waste. The cassette has an outer cavity edge defining the outer periphery of the cassette. The inner cavity edge also defines an inner cavity wall. The outer cavity edge also defines and outer cavity wall. The inner cavity wall and outer cavity wall are joined by a bottom wall and/or a top panel, thereby forming a liner cavity. The bottom wall has an inner edge and an outer edge. The top panel has an inner edge and an outer edge. In certain embodiments, the inner edge of any wall or panel coincides with or is proximal to the inner edge of any adjacent wall or panel thereby forming a portion of the liner cavity, and likewise is true for outer edges of such walls and/or panels. 
     In some embodiments, the cassette has only portions of the liner cavity, for instance, the outer or inner cavity wall the bottom wall, or top panel. In these embodiments, the wall, panel, surface or edge defining such a wall, panel or surface, may vary in at least at two positions along the outer perimeter or inner perimeter of the cassette. Optionally, these embodiments have a liner film attached to such wall or panel at a first end of the liner film, and the second end of the liner film is closed, closeable, sealed, sealable to form a bag-like structure. Such bags may have pleats or folds to provide expansive storage properties. In such embodiments, the inner wall, outer wall, surface, bottom wall, and/or top panel may have a variable geometry such that the height is variable along the wall or surface, or the width is variable along the wall, panel or surface, or both the height and width are variable. 
     The film dispensing cassette has a central passage through which film extends and creates a barrier between the waste received within the film and the body of the disposal device. The liner film is at least partially contained, prior to use and during use, within a liner cavity in the cassette. The liner film is at least partially contained within the liner cavity until the liner film is exhausted and the cassette needs to be replaced. The liner cavity has a cross-sectional geometry that varies around a perimeter of the cassette at least at two different points. 
     The liner cavity, for example, has a first position along the perimeter of the cassette with a cross-sectional geometry generally equal to a second position along the perimeter of the cassette having a second cross-sectional geometry. The first cross-sectional geometry is different from the second cross-sectional geometry. 
     In further embodiments, the cassette has an outer cavity wall generally opposite the inner cavity wall and defining the outer perimeter of the liner cavity. In further embodiments, the cassette includes a bottom cavity wall that at least partially connects the outer cavity wall and the inner cavity wall. In yet other embodiments, the cassette has a top panel that assists in the at least partial containment of the liner film within the liner cavity (prior to and during use until the liner film is exhausted). In some such embodiments, the top panel is sized such that a generally uniform cavity opening is provided and enables generally consistent dispensation of the liner film at any given position along the perimeter of the cassette, regardless of whether the maximum height and/or width at such positions are the same or different. 
     In some embodiments, the geometry of the cassette is such that, when resting on a flat surface such as a shelf or table, the cassette is balanced and stable so as not to rock. Further, when two or more cassettes are stacked together, the top of each cassette is designed to geometrically mate with the bottom of another cassette so as to maintain relative position to each other. 
     The present disclosure is described herein in terms of aspects and embodiments of those aspects that include elements or features that may be included with the aspects. The identified embodiments may be included with the aspect of the invention singularly or in combination with any of the other identified embodiments as will be described herein below in the Detailed Description. The features and advantages of the present invention will become apparent in light of the detailed description of the invention provided below, and as illustrated in the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side perspective of a waste disposal device. 
         FIG. 2  is a front perspective of a waste disposal device, illustrating a lid rotated to an open position. 
         FIG. 3  is a diagrammatic perspective view of a film-dispensing cassette with a segment of liner film drawn out of a liner cavity and through a central passage of the cassette. 
         FIG. 4  is a diagrammatic top view of a film-dispensing cassette embodiment. 
         FIG. 5  is a diagrammatic side view of a film-dispensing cassette embodiment. 
         FIG. 6  is a diagrammatic top view of a film-dispensing cassette embodiment. 
         FIG. 6A  is a diagrammatic sectional view of the cassette shown in  FIG. 6 , showing a liner cavity cross-section at section  6 A- 6 A. 
         FIG. 6B  is a diagrammatic sectional view of the cassette shown in  FIG. 6 , showing a liner cavity cross-section at section  6 B- 6 B. 
         FIG. 6C  is a diagrammatic sectional view of the cassette shown in  FIG. 6 , showing a liner cavity cross-section at section  6 C- 6 C. 
         FIG. 6D  is a diagrammatic sectional view of the cassette shown in  FIG. 6 , showing a liner cavity cross-section at section  6 D- 6 D. 
         FIG. 7  is a diagrammatic side view of the cassette embodiment shown in  FIG. 6 . 
         FIG. 8  is a diagrammatic top view of a film-dispensing cassette embodiment. 
         FIG. 8A  is a diagrammatic sectional view of the cassette shown in  FIG. 8 , showing a liner cavity cross-section at section  8 A- 8 A. 
         FIG. 8B  is a diagrammatic sectional view of the cassette shown in  FIG. 8 , showing a liner cavity cross-section at section  8 B- 8 B. 
         FIG. 8C  is a diagrammatic sectional view of the cassette shown in  FIG. 8 , showing a liner cavity cross-section at section  8 C- 8 C. 
         FIG. 8D  is a diagrammatic sectional view of the cassette shown in  FIG. 8 , showing a liner cavity cross-section at section  8 D- 8 D. 
         FIG. 9  is a diagrammatic side view of the cassette embodiment shown in  FIG. 8 . 
         FIG. 10  is a diagrammatic top view of a film-dispensing cassette embodiment. 
         FIG. 10A  is a diagrammatic sectional view of the cassette shown in  FIG. 10 , showing a liner cavity cross-section at section  10 A- 10 A. 
         FIG. 10B  is a diagrammatic sectional view of the cassette shown in  FIG. 10 , showing a liner cavity cross-section at section  10 B- 10 B. 
         FIG. 10C  is a diagrammatic sectional view of the cassette shown in  FIG. 10 , showing a liner cavity cross-section at section  10 C- 10 C. 
         FIG. 10D  is a diagrammatic sectional view of the cassette shown in  FIG. 10 , showing a liner cavity cross-section at section  10 D- 10 D. 
         FIG. 11  is a diagrammatic side view of the cassette embodiment shown in  FIG. 10 . 
         FIG. 12  is a diagrammatic perspective view of a cassette embodiment. 
         FIG. 13  is a diagrammatic perspective view of a cassette embodiment. 
         FIG. 14  is a diagrammatic perspective view of a cassette embodiment. 
         FIG. 14A  is a diagrammatic section view of the cassette shown in  FIG. 14 , showing a line cavity cross-section at  14 A- 14 A. 
         FIG. 15  is a diagrammatic section view of a cassette embodiment overlaid with a circle. 
         FIG. 16  is a diagrammatic section view of a cassette embodiment overlaid with a circle. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, a film-dispensing cassette  20  for use in a waste-disposal device is provided. The waste disposal device and the cassette  20  may be used for storing any type of waste items, but are well suited for the disposal of diapers, feminine hygiene, adult incontinence, and pet waste. The cassette includes a film that is at least partially stored within the cassette, which film is configurable to form a bag-like structure. The cassette  20  includes a central passage  44  through which waste is passed. The present cassette  20  may be used with a variety of different types of waste-disposal devices, and therefore is not limited to any particular type of waste-disposal device  22 . To facilitate the description of the present cassette  20 , an exemplary non-limiting embodiment of a waste disposal device  22  with which the present cassette  20  may be used is provided below. 
     The waste disposal device  22  includes a housing  24 , a lid  26 , and a foot pedal  28 . To facilitate the description herein, the waste disposal device  22  is described herein as having a width that extends along an X-axis, a depth that extends along a Y-axis, and a height that extends along a Z-axis; where X, Y, and Z are orthogonal axes. The housing  24  may also be described as having two side panels  30 A,  30 B that extend depthwise between a front panel  32  and a rear panel  34 . The housing  24  may include a door  33  that provides access to an interior storage region  29 . In some embodiments, the housing has a bin  33  a. The bin  33  a can be connectable to the door  33  such that bin  33  a is removable when the door  33  is opened and/or removable from the housing  24 . 
     Depressing the foot pedal  28  operates a linkage (not shown) that causes the lid  26  to open and provides access to the inner storage region  29  of the waste disposal device  22 . In some waste-disposal devices  22 , depressing the foot pedal  28  also causes a mechanism within the waste-disposal device  22  (e.g., a liner clamping assembly) to move to an “open position” where it does not impede deposit of waste within a liner disposed within the inner storage region. When the foot pedal  28  is released, the lid  26  closes automatically and the mechanism returns to its normally closed position (e.g., an “at rest” state). In the closed position, the mechanism clamps (or otherwise closes) the liner (e.g., to mitigate odor emanation). 
     Some waste disposal devices  22  are configured to permit insertion or removal of a film-dispensing cassette  20  in the portion of the housing disposed vertically below the lid  26 . The exemplary embodiment shown in  FIGS. 1 and 2  has such a configuration. Other waste disposal devices  22  may be configured to permit insertion or removal of a film-dispensing cassette  20  from a front surface of the housing  24 . Embodiments of the present film-dispensing cassette  20  may be used in either of these configurations, and as indicated above, the present cassette  20  is not limited to use in any particular waste disposal device  22 . 
     Referring to  FIGS. 3-5 and 13-14 , the present film-dispensing cassette  20  may be described as having a widthwise extending axis  36  (e.g., extending in an X-axis direction) and a depthwise extending axis  38  (extending in a Y-axis direction) that orthogonally bisect a center point. In the X-Y plane, the cassette  20  may be symmetrical relative the one or both axes  36 ,  38 , or may be non-symmetrical relative to one or both axes  36 ,  38 . The cassette  20  includes a liner cavity  40  for containing a supply of liner film  42  and a central passage  44 . The liner cavity  40  may be described as having a forward region  46 , an aft region  48 , a first side region  50 , and a second side region  52 . The first and second side regions  50 ,  52  extend between the forward and aft regions  46 ,  48 , on opposite sides of the central passage  44 . As shown in  FIG. 4 , axes  36 ,  38  split cassette  20  into four general sectors, a forward first side region  37 , a forward second side region  39 , an aft first side region  41 , and an aft second side region  43 . 
     The liner cavity  40  may assume a variety of configurations to hold the supply of liner film  42 . In the embodiment shown in  FIGS. 3-5 and 13-14 , the liner cavity  40  is defined by an inner cavity wall  54 , a bottom cavity wall  56 , and an outer cavity wall  58 . The inner cavity wall  54  is radially inside of the outer cavity wall  58  (e.g. the inner cavity wall  54  is disposed closer to the center of the central passage  44  than the outer cavity wall  58 ) and the bottom cavity wall  56  extends between and at least partially connects with the inner cavity wall  54  and the outer cavity wall  58 . Although the inner cavity wall  54 , bottom cavity wall  56 , and outer cavity wall  58  are shown in  FIGS. 3-5  as having a solid wall structure, they are not limited to a solid wall configuration; e.g., one or more of the inner cavity wall  54 , bottom cavity wall  56 , and outer cavity wall  58  may assume any configuration adequate to hold the supply of liner film  42 . The liner cavity  40  may be formed as a continuous one-piece structure (e.g., the inner and outer cavity walls  54 ,  58  and bottom cavity wall  56  formed as a continuous one-piece structure), or they may be multiple pieces connected together. 
     The inner cavity wall  54 , bottom cavity wall  56 , an outer cavity wall  58  are relatively configured to give the liner cavity  40  an open channel shape. The inner cavity wall  54  and the outer cavity wall  58  may be parallel to one another (e.g., in the Z-axis direction), or they may be non-parallel (e.g., skewed at an angle) relative to one another, or the distance between the two may vary at different points. The bottom cavity wall  56  may be planar or non-planar (e.g., arcuate). The bottom cavity wall  56  may extend perpendicular to the inner and outer cavity walls  54 ,  58 , or it may be skewed at an angle other than ninety degrees. In the embodiments shown in  FIGS. 3-5 , the opening  60  (e.g., liner cavity opening) of the liner cavity  40  extends between a top surface edge of the inner cavity wall  54  and a top surface edge of the outer cavity wall  58 . In the embodiment shown in  FIGS. 3-5 , the inner cavity wall  54  defines the geometry of the central passage  44 . In alternative embodiments, the central passage  44  may be defined by a structure other than the inner cavity wall  54 . 
     The cross-sectional geometry of the liner cavity  40  varies depending upon the location of the cross-section around the perimeter of the cassette  20 . The term “cross-sectional geometry” of the liner cavity  40  (at a given perimeter position) is defined herein as the geometry of a cross-sectional plane (e.g., extending in the X-Z plane, or the Y-Z plane, etc.) that is perpendicular to inner cavity wall  54  and the outer cavity wall  58 . For purposes of describing the cross-sectional geometry of the liner cavity  40 , the “height” of the liner cavity  40  extends in a Z-axis direction from the opening  60  of the liner cavity  40  to the interior surface of the bottom cavity wall  56 , and the “width” of the liner cavity  40  extends between the interior surfaces of the inner and outer cavity walls  54 ,  58 . A liner cavity  40  according to the present disclosure includes at least two different cross-sectional geometries; e.g., a first cross-sectional geometry with a maximum height (Hmax1) that differs from the maximum height (Hmax2) of a second cross-sectional geometry, and a maximum width (Wmax1) that differs from the maximum width of the second cross-sectional geometry (Wmax2). Further varying geometries are provided for, such as Hmax3 . . . HmaxN, and Wmax3 . . . WmaxN. Stated another way, the maximum height at a first location along the perimeter of the cassette  20 , such as in the forward region  46 , may be different than the maximum height along the perimeter of the cassette  20  in the first side region  50 , as shown in  FIG. 3 . As demonstrated by the exemplary embodiment in  FIG. 4 , the aft region  48  is shown to have a maximum width that is different than the maximum width in the second side region  52 . 
     Typically, the cross-sectional area of the liner cavity  40  (i.e., the area of the cross-sectional plane that is perpendicular to inner cavity wall  54  (i.e. a vertical slice) and the outer cavity wall  58  that resides within the liner cavity  40 ; i.e., in the ZY or ZX plane) remains substantially constant around the cassette perimeter to enable the liner cavity  40  to accept a uniform volume of liner film  42  around the cassette perimeter. 
     The cassette  20  embodiment shown in  FIGS. 6 and 7 , for example, has a liner cavity  40  with a cross-sectional geometry that varies around the perimeter of the liner cavity  40 .  FIGS. 6A-6D  are diagrammatic cross-sections of the liner cavity  40  at the respective positions indicated in  FIG. 6 ; i.e., an aft region position ( FIG. 6A ), at a forward region position ( FIG. 6B ), a first side region position ( FIG. 6C ), and a second side region position ( FIG. 6D ). As can be seen in  FIGS. 6A-6D , the liner cavity  40  has a height H 1  and a width W 1  at the aft region position, a height H 2  and a width W 2  at the first side region position, a height H 3  and a width W 3  at the second side region position, and a height H 4  and a width W 4  at the forward region position. In this embodiment, the height and width at the liner cavity side region positions are substantially equal one another (i.e., H 2 =H 3  and W 2 =W 3 ), the height of the liner cavity  40  at the aft region position is greater than the height of the liner cavity  40  at the forward region position (i.e., H 1 &gt;H 4 ), and the width of the liner cavity  40  at the aft region position is less than the width of the liner cavity  40  at the forward region position (i.e., W 1 &lt;W 4 ). The cross-sectional area of the liner cavity  40  at the aforesaid perimeter positions are substantially equal one another. In the particular configuration of this embodiment shown in  FIGS. 6A-6D , the cross-sectional geometry of the liner cavity  40  in the aft region  48  and a substantial portion of each side region  50 ,  52  is the same, the cross-sectional geometry of the liner cavity  40  in the forward region  46  differs from the cross-sectional geometry of the aft and side regions, and a portion of each side region transitions between the two cross-sectional geometries (e.g., see  FIG. 7 ). 
     In an alternative configuration (see  FIGS. 8, 8A-8D, and 9 ), the cross-sectional geometries of the liner cavity  40  of the first side region  50 , a portion of the aft region  48 , and a portion of the forward region  46  may be the same (e.g., each have width W 5  and height H 5 ), and the cross-sectional geometry of the second side region  52  (e.g., width W 6  and height H 6 ) may differ therefrom. In this configuration, a portion of the aft region  48  and the forward region  46  transition between the two cross-sectional geometries. 
     In another alternative configuration, the cross-sectional geometry of the liner cavity  40  may be substantially constant in the first and second side regions  50 ,  52  and substantially constant in the forward and aft regions  46 ,  48 . The cross-sectional geometry of the liner cavity  40  in the side regions  50 ,  52  is, however, different (e.g., narrower widthwise) from the cross-sectional geometry of the forward and aft regions  46 ,  48 .  FIGS. 10, 10A-10D, and 11  illustrate such a geometry wherein the cross-sectional geometry of the forward and aft regions  46 ,  48  has a height H 7  and a width W 7 , and the cross-sectional geometry of the first and second liner cavity side regions  50 ,  52  has a height H 8  and a width W 8 . The height of the liner cavity forward and aft regions  46 ,  48  is less than the height of the liner cavity side regions  50 ,  52  (H 7 &lt;H 8 ), and the width of the liner cavity forward and aft regions  46 ,  48  is greater than the width of the liner cavity side regions  50 ,  52  (W 7 &gt;W 8 ). This liner cavity  40  configuration permits a widthwise narrower cassette  20  configuration relative to a cassette  20  with a liner cavity  40  having uniform cross-sectional geometry around the entire perimeter for a given central passage  44  maximum width. A further cassette  20  embodiment may adopt the converse configuration; e.g., one in which the cross-sectional geometry of the liner cavity  40  in the side regions  50 ,  52  is wider widthwise than the cross-sectional geometry of the forward and aft regions  46 ,  48 . This liner cavity  40  configuration permits a depthwise narrower cassette  20  configuration relative to a cassette  20  with a liner cavity  40  having uniform cross-sectional geometry around the entire perimeter for a given central passage  44  maximum depth. 
     In some embodiments, the liner cavity  40  does not have a uniform cross-sectional geometry about the entire inner upper edge  54   a , inner lower edge  54   b , or outer upper edge  58   a , or outer lower edge  58   b . In some such embodiments, the inner perimeter as defined by inner upper edge  54   a  or inner lower edge  54   b , or outer perimeter as defined by  58   a  or  58   b , with respect to the other, undergo a translation such that a further narrower region along a portion of the liner cavity  40  is achieved without growing the height in that region. In some such embodiments, a maximum dimension (i.e. widthwise and/or depthwise) can be achieved in a region of the cassette  20  to provide an advantageous configuration for waste disposal, as contemplated by the present disclosure. Accordingly, the translation can occur with respect to the X and/or Y axes such that the shift is in the XY plane. 
     In some embodiments, a cassette  20  is provided having a balanced geometry. As described herein, “balanced” refers to a cassette  20  that is able to rest upon a substantially planar surface with little or no oscillation, such that it is generally stabilized (e.g., stays in a static position in the absence of an applied force). These embodiments are preferred in terms of stacking multiple cassettes  20 , and/or configuring cassettes  20  for shipping and/or storage. In some embodiments, the cassette  20  has at least two portions with a substantially flat bottom cavity wall  56  that act as stabilizing means. Such regions are referred to as plateaus  57  as shown in  FIG. 9 . For example, a cassette  20  as exemplified in  FIGS. 6-7  may have an H 1  and H 2  that are substantially equal, and/or an H 3  and H 4  that are substantially equal. In some embodiments the length of the region where such height is substantially constant (i.e. the plateau  57 ) is at least 10% of the length of the maximum depthwise direction have H 1  substantially equal to H 2  for at least about 10% of the length of region  50  and/or region  52 . Alternatively, the length can be respective to the maximum widthwise dimension. In some embodiments, the plateau  57  where such height is substantially constant is at least 15%, at least 20%, at least 25%, at least 30%, at least 50%, or at least 75% of the maximum dimension (i.e., widthwise or depthwise). 
     In the aforementioned embodiments, the top panel  62  may also have similar plateaus  57  as the bottom cavity wall  56 , such that cassettes  20  are balanced when stacked, and/or are easy to align in a stacked configuration. 
     In some of the aforementioned embodiments, the plateaus  57  can also help properly orient the cassette  20  into waste disposal device  22 , where waste disposal device  22  has a receiving geometry suitably configured to mate with such plateaus  57 . 
     Heights, for exemplary purposes, H 7  and H 8  vary between about 40 mm and about 70 mm. In some embodiments, H 7  and H 8  are between about 30 mm and about 50 mm. The ratio of H 7  to H 8  is between about 0.5 to about 1.0. 
     Widths W 7  and W 8  vary between about 10 mm and about 40 mm. In some embodiments, W 7  and W 8  are between about 20 mm and about 35 mm. The ratio of W 7  to W 8  is between about 0.25 to about 1.0. 
     In some embodiments, the ratio of H 7  to H 8  is between about 0.8 and 1.0, and the ratio of W 7  to W 8  is between about 0.8 and 1.0. The ratio of H 7  to W 7  is between about 1.0 to about 7.0, and the ratio of H 8  to W 8  is between about 1.0 to about 7.0. In some embodiments, the ratio of H 7  to W 7  is between about 1.0 to about 2.0, and the ratio of H 8  to W 8  is between about 1.0 to about 2.0. In some embodiments, the ratio of H 7  to W 7  will be less than or greater than the ratio of H 8  to W 8 . 
     In some embodiments, the cross-sectional geometry of the liner cavity  40  may be asymmetrical in one or more of the first and second side regions  50 ,  52 , respectively, and the forward and aft regions  46 ,  48 , relative to the other regions or sectors  37 ,  39 ,  41 ,  43 . The asymmetry amongst the regions  46 ,  48 ,  50 ,  52  or sectors  37 ,  39 ,  41 ,  43  can be utilized to accommodate structural elements within the waste disposal device  22 . For example, some waste disposal device  22  embodiments may include structure for securing the cassette  20  within the device  22 , which structure is disposed on a single side of the device. Embodiments of the present cassette  20  can be asymmetrically configured to provide clearance relative to the structure, and still provide the desired cassette  20  orientation within the device  22 . For example,  FIG. 12  shows an aft region with an asymmetrical configuration (e.g., a section  49  of the aft region  48  wherein the bottom cavity wall  56  deviates from the contour of the remainder of the aft region  48 ) relative to, for example, the forward region  46 . In this type of liner cavity  40  configuration (and others like it), the cross-sectional area of the liner cavity  40  (i.e., the area of the cross-sectional plane that is perpendicular to inner cavity wall  54  and the outer cavity wall  58  that resides within the liner cavity  40 ) may not be substantially constant around the entire cassette perimeter; e.g., the cross-sectional area of the liner cavity  40  in the asymmetrical portion may be less than the cross-sectional area of the liner cavity  40  elsewhere around the perimeter of the cassette  20 . 
       FIGS. 15-16  provide a top view of and overlays a cassette  1000  and an exemplary cassette  20  of the present disclosure.  FIGS. 15-16  demonstrate embodiments having one or more splines configured to create a generally arcuate shape defining the front region  46 , aft region  48  and/or side regions  50 ,  52 , of cassette  20 . For instance, four splines may be connected such that a first spline  400  and a second spline  402  are generally the same geometry, and a third spline  404  and fourth spline  406  are generally the same geometry but are different from the geometry of the first and second splines  400 ,  402 . This exemplary combination of splines provides symmetry with respect to the depthwise axis  920 . In certain embodiments, the cassette  20  may be shaped (due the configuration of the splines defining the front region  46 ) such that the maximum widthwise dimension  910  in cassette  20  is between the front region  46  of the cassette  20  and the midpoint  1012  of exemplary known round cassette  1000  length. In other embodiments, there may be more than four splines to further augment geometry, such as five, six, seven, eight, n, etc. In alternative embodiments, there are three splines  500 ,  502 ,  504 , such that one spline does not correspond with another spline. 
     In some embodiments, one or more splines provide a maximum lengthwise dimension between the front region  46  and the midpoint  1012  (e.g., distance  916 +distance  914 ), and/or a maximum widthwise dimension aligned with the maximum widthwise dimension  910 . 
     The maximum widthwise dimension of the central passage  44  is greater than or equal to 100 mm. In further embodiments, the maximum widthwise dimension is between about 100 mm to about 140 mm. In further embodiments, the maximum widthwise dimension is greater than about 110 mm. In some embodiments, the maximum widthwise dimension of the central passage  44  is about 10% greater than the maximum widthwise dimension of known cassette  1000 . 
     In further embodiments, splines are utilized to maximize the area of the central passage to reduce difficulty with inserting messy, large and/or odd-shaped waste such as diapers or waste disposing accoutrements such as scoops. 
     As shown in exemplary  FIGS. 15-16 , the cassette  1000  has a shorter central passage  1002  diameter in the widthwise and depthwise directions than the exemplary cassette  20  and likewise the outer wall  1004  has a smaller diameter. Cassette  20  in  FIG. 16  also has its maximum widthwise dimension  910  situated below the midpoint  1012  of cassette  1000  a distance  914  such that the maximum widthwise dimension  910  of the cassette  20  is closer to the front region  46  and thus helps reduce the distance a user&#39;s arm/hand travels to deposit the waste into central passage  44 . In some embodiments, the location of the maximum widthwise dimension  910  being within the front region  46  is due to the variable cross-section permitting a narrower liner cavity  40  dimension in the front region than in the aft region. Distance  914  is at least 10 mm and can be up to about 70 mm. In another embodiment, the distance  916  between the intersection of the maximum widthwise dimension  910  and the depthwise axis  920  and the front region  46  of the central passage  44  is between about 20 mm and about 70 mm. In further embodiments, distance  916  is between about 50 mm and about 70 mm. In some embodiments, distance  916  is less than 60 mm. 
     The distance  918  between 1) the intersection of the maximum widthwise dimension  910  and the depthwise axis  920  and 2) the aft region  48  of the central passage (e.g., intersection of the inner cavity wall  54  of the aft region and the depthwise axis  920 ) is between about 50 mm and about 140 mm. In further embodiments, the distance  918  is between about 50 mm and about 90 mm. In further embodiments, the distance  918  is greater than 60 mm. In further embodiments, the distance  918  is greater than 70 mm. The distance  918  is greater than or equal to 50% of the entire length of the maximum depthwise dimension while distance  916  is less than or equal to 50% of the entire length of the maximum depthwise dimension. 
       FIGS. 15-16  also demonstrate cassette  20  having longer depthwise dimension such that larger waste can be deposited. The maximum depthwise dimension is located along the depthwise axis such that large waste does not need to be pivoted to enter central passage; it can be deposited straight-on from the front of the pail without undue pivoting of the waste. In some embodiments, the maximum depthwise dimension is the perpendicular bisector of the front edge (or front panel  32 ) of the waste disposal device  22 . 
       FIG. 15  further demonstrates central passage  44  with a larger forward portion area than that of cassette  1000 , where the forward portion is defined as the portion of the central passage  44  between the forward region  46  extending to the maximum widthwise dimension  910 . This can be described as the area in the forward portion of the central passage  44  to the product of the maximum widthwise dimension and the distance  916  for given a constant perimeter of liner film  42 . The equation is generally represented as: 
       Forward Area Aspect Ratio=(forward portion area)/(910*916) 
     The Forward Area Aspect Ratio is between about 0.5 and about 1.5. 
       FIG. 15  demonstrates a second aspect ratio showing the redistribution of area with cassettes  20  of the present disclosure, focusing on the aft portion area. The aft portion area is defined as the portion of the central passage  44  between the aft region  48  and the widthwise axis extending through the midpoint  1012  of the central passage  44  (i.e. corresponding to distance  918  minus distance  914 , as per  FIG. 15 ). This can be described as the Aft Area Aspect Ratio of the area in the aft portion of the central passage  44  to the product of a first widthwise dimension  1010  at midpoint  1012  and distance  918  minus distance  914 , for given a constant perimeter of liner film  42 . Aft Area Aspect Ratio=(aft portion area)/( 1010 *( 918 − 914 )). 
     The Aft Area Aspect Ratio is between about 0.3 and about 2.0. 
     A further ratio of the Forward Area Aspect Ratio to the Aft Area Aspect Ratio is called the Maximum Area Ratio. The Maximum Area Ratio is between about 0.25 and about 5. Generally, this describes the relative distribution of the surface area of the central passage  44 . In some embodiments, the Maximum Area Ratio is between about 0.25 and about 1. In further embodiments, the Maximum Area ratio is less than about 0.9. In other embodiments, the Maximum Area Ratio is between about 1 and about 5. In yet other embodiments, the Maximum Area Ratio is greater than about 1.1. 
       FIG. 16 , although showing an exemplary embodiment of central passage  44 , can also similarly illustrate the outer cavity wall  58 . Both  FIGS. 15-16  demonstrate geometries of the present disclosure that relocate surface area of the cassette  20  such that a larger opening space is located in the forward region and/or a larger opening space is located in the aft region in order to accommodate oddly shaped waste. 
     The above described liner cavity  40  configurations represent non-limiting examples of a liner cavity  40  having a cross-sectional geometry that varies at least at two different points along the perimeter of the cassette  20 . The present disclosure is not limited to these examples. One skilled in the art understands that different geornettic configurations such as circles, ovals, arcuate shapes, undulating shapes, stepped shapes, chamfers, triangles, Reuleaux triangles, frusto-conical shapes, conics, other polygons and combinations thereof are within the scope of the present disclosure (in both vertical and/or horizontal cross-sectional orientations). For instance, in a generally triangular shaped cross-section, Wmax1 may describe the width of the panel defining the base of the triangle and Hmax1 might correlate to the perpendicular bisector of the base extending to the opposite vertex. One skilled in the art understands that the area of the triangle in this case would be ½*(Hmax1*Wmax1). In instances where a portion of the cross-section was, for example, generally triangular and a portion of the cross-section was, for example partially circular, in certain embodiments the cross-sectional area of each would be generally equal such that ½*(Hmax1*Wmax1)≈Π((Hmax2)/2)2). Other areas can be calculated via known mathematical calculations and/or via integration. 
     The varying cross-sectional geometry of the liner cavity  40  provides several advantages beyond those provided above. For example, the varying cross-sectional geometry makes it easy for a user to identify the correct orientation of the cassette  20  within the waste disposal device  22  (e.g., the at least partially asymmetric shape can only be inserted into the waste disposal device  22  in a single orientation), and yet permits a uniform volume of liner film  42  (i.e. such that any given cross-sectional slice along the z axis has substantially the same cross-sectional area) to disposed in the liner cavity  40  around the entire liner cavity perimeter. For those embodiments that have a substantially constant cross-sectional area around the perimeter of the cassette, the uniform volume of liner film  42  around the entire liner cavity perimeter facilitates uniform liner dispensing within the waste disposal device  22 . The varying cross-sectional geometry of the liner cavity  40  can also make the cassette  20  easier to install into and be removed from the waste disposal device  22 , e.g., a cassette  20  having a shallower front portion may be rotated relative to the waste disposal device  22  to facilitate removal, as opposed to a cassette  20  that installed/removed along a purely vertical axis. Also as described above, the varying cross-sectional geometry of the liner cavity  40  can also accommodate asymmetric positioning of structural elements within the waste disposal device  22 . The varying cross-sectional geometry enables the cassette  20  to “sit” within an asymmetric cassette “seat”, and still provide the desired cassette  20  orientation within the device  22 . 
     The liner film  42  is a film formed in a closed perimeter configuration that extends a length. The closed perimeter configuration is such that the liner material has a continuous perimeter that extends lengthwise; e.g., the configuration may be described as “tubular”. The cross-sectional configuration of the liner film  42  (i.e., the cross-sectional perimeter shape) may vary depending on the particular configuration. The liner film  42  is comprised of a material that is flexible, capable of being stored within the liner cavity  40 , capable of being readily drawn out of the liner cavity  40 , and capable of being formed in a closed configuration (e.g., knotted) as will be described below. A flexible plastic film is an example of an acceptable liner film  42 . The liner film  42  can include one or more layers of polyethylene, polypropylene, polyester, EVA, EVOH, nylon, tie resin, and may further include additives such as carbon, calcium carbonate, talc, titanium dioxide and slip agents. Embodiments of the liner film  42  may include agents that mask odor such as fragrance, mitigate odors including odor absorbers and odor absorbers, etc. 
     The liner film  42  is stored within the liner cavity  40  in an orientation that allows incremental portions of the liner to be drawn out of the liner cavity  40 . The cassette  20  may be configured such that the liner film  42  can be drawn out of the liner cavity  40  through an opening disposed around the cassette perimeter at the opening  60 ; e.g., the cassette  20  diagrammatically shown in  FIG. 3  includes a top panel  62  that substantially covers the opening  60 , creating the opening through which the liner film  42  is drawn out of the liner cavity  40 . The present cassette  20  is not limited to any particular liner path configuration; e.g., liner film  42  may alternatively be drawn out of the liner cavity  40  through the bottom cavity wall, inner cavity wall  54 , or the outer cavity wall  58  of the liner cavity  40 . The present cassette  20  is also not limited to any particular manner for arranging the liner film  42  within the liner cavity  40  (e.g., folded, pleated, etc.), provided the liner film  42  can be readily drawn out from the liner cavity  40  on demand by the user. 
     In some embodiments, the cassette  20  includes a top panel  62  to assist with containing liner film  42  within the liner cavity  40  prior to and during use until the liner film  42  is exhausted. The top panel  62  also assists in controlling the dispensation of the liner film  42 . In embodiments of the present disclosure where the maximum width varies around the perimeter of cassette  20 , the top panel  62  can also vary to provide opening  60  with generally the same width at any given point around the cassette  20  perimeter. The top panel  62  can be integral with the cassette  20  via a living hinge and/or can be connected to the cassette via ultrasonic welding, heat, adhesives, or mechanically attached with snap-fits, detents, press-fits, etc. . . . 
     U.S. Pat. No. 4,934,529 to Tannock, and U.S. Pat. No. 5,056,293 to Richards et al. describe methods for loading liner film into cassettes and are hereby incorporated by reference. Loading the liner film  42  into the liner cavity  40  requires moving liner film  42  over a mandrel such that the liner film  42  rests outward of the mandrel. The mandrel is sized less than the diameter of the liner film  42  but is sized such that the liner film  42  is able to move along the length of the mandrel (as per process parameters and mechanics) without undue resistance. The mandrel is sized and shaped similarly to the inner cavity wall  54  of cassette  20  (i.e. taking a horizontal slice in the XY plane of the mandrel that is proximal and/or adjacent and inner cavity wall  54 ) such that the liner film  42  travels along the length of the mandrel towards the open end of cassette  20  such that liner film  42  can be loaded into liner cavity  40 . The peripheral length of the liner film  42  is slightly greater than the peripheral length of the inner cavity wall  54  and the peripheral length of the liner film  42  is slightly less than peripheral length of the outer cavity wall  58 . After the appropriate length of liner film  42  has been received into liner cavity, the top panel  62  is placed over the opening  60  to at least partially contain the liner film  42  in the liner cavity  40 . 
     The top panel  62  may optionally include a removal portion  66  such that it is frangible or peelable, such as a peel tab, label, sticker, perforation or tear strip. Removal portion  66  contains the liner film placed inside the liner cavity  40  until the removal portion is removed to reveal the cavity opening. In certain embodiments, the removal portion  66  is located adjacent the outer perimeter (i.e. proximal the outer cavity wall  58 ). In other embodiments, the removal portion  66  is located adjacent the inner perimeter (i.e. proximal the inner cavity wall  54  and/or the central passage  44 ). In yet other embodiments, the perforation or tear strip (e.g., removal portion  66 ) is located towards the middle portion of the top panel  62 , bottom cavity wall  56 , outer cavity wall  58  or inner cavity wall  54 . 
     As the liner film  42  is loaded into the liner cavity  40 , the liner film  42  may creep outward from the liner cavity and may present issues when the top panel  62  is placed and connected onto the cassette  20  (i.e. the liner film  42  could be pinched at a point where the top panel  62  is connected to the cassette  20 ). To minimize quality issues, the assembly process may provide for pins (or fingers) that help depress the liner film  42  into the liner cavity  40  as it is being loaded. In some embodiments, the top panel  62  has apertures sized to receive such pins such that the top panel  62  can pass along the pins and ultimately connect to the cassette  20  prior to removal of the pins (i.e. such that the liner film  42  is depressed to a position away from the connection point(s) between the top panel  62  and cassette  20  to prevent pinching). In alternate embodiments, pins or fingers may be designed to fit around the top panel  62  (i.e. above and/or below) or have a slim profile to avoid apertures in the top panel. In an exemplary embodiment shown in  FIG. 13 , the top panel  62  has an undulating shape such that the pins or fingers can fit within local at least one concave portion  21  of the top panel  62 . In some embodiments, the top panel  62  has at least 2 concave portions  21 . In some such embodiments, the pins or fingers have side action (i.e., lateral or rotational motion) as opposed to solely linear vertical motion requiring the apertures in the top panel  62 . In yet other embodiments as exemplified in  FIG. 14A , the bottom surface  65  of top panel  62  (i.e. the surface facing the liner cavity  40  and in contact with liner film  42 ) may have ribs or protrusions  68  to help push liner film  42  downward into the liner cavity  40  and away from connection point(s) between the top panel  62  and cassette  20 . 
     The present cassette  20  can be removed and replaced from the waste disposal device  22  as needed. For example, in the waste disposal device  22  embodiment shown in  FIGS. 1 and 2 , the cassette  20  can be replaced by opening the lid  26 , removing the empty cassette  20  from the housing (if necessary), and placing an unused cassette  20  into the housing  24 . The user then withdraws a length of the liner film  42  from the liner cavity  40 , feeds it through the central passage  44 , and into the inner storage region  29 , so that the free end of the liner film  42  is disposed near the lower end of the bin  33  a. The user then closes off the free end of the liner film  42  to form a liner film “bag” (e.g., by tying the liner film  42  into a knot adjacent the free end) and closes the bin  33  a. In this configuration, the waste disposal device  22  (and specifically the liner film  42 ) is ready to receive waste such as, but not limited to, disposable diapers, nappies, training pants, feminine hygiene articles, and incontinence products. Gravitational forces urge whatever waste is deposited into the liner film bag toward the closed-off free end of the liner film bag. When the liner film bag is full of waste, the upper end of the liner film  42  is separated from the supply of liner film  42  (e.g. by cutting the liner film  42  at a point above the stored waste), and the bag is removed from the waste disposal device  22 . The just-separated end of the liner film  42  may then be closed (e.g., by knot or fastener) and the bag disposed of The process is then repeated; e.g., the user withdraws another length of the liner film  42  from the liner cavity  40 , drawing it through the cassette central passage  44  and into the bin  33  a. The user then closes off the free end of the liner material to form a new liner film bag. 
     While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. For instance, specific embodiments providing geometries in a first configuration could be flipped or rotated. Further, different combinations of different geometries are also within the scope of the present disclosure. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed herein as the best mode contemplated for carrying out this invention.