Abstract:
A method of reducing sheet product waste generated during use of a sheet product dispenser in a particular location and over a broad range of usage rates includes designing a dispenser. The design includes determining a desired housing size to obtain a top to bottom height for sheet product roll storage within the housing, dividing the height by two to obtain a maximum roll diameter, locating two roll holders in the housing so that each holder may accept a roll having the maximum roll diameter, positioning a first roll of the maximum roll diameter in a first one of the two roll holders, and positioning a second roll of the maximum roll diameter in a second one of the two roll holders so that two rolls of equivalent length are configured to be dispensed sequentially from the dispenser. The installation and use of two rolls of maximum roll diameter reduces waste. Dispensers formed according to this method are also described.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/731,812, filed Nov. 30, 2012, the contents of which are incorporated herein by this reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates generally to a method of reducing waste when using a product dispenser, and to rolled sheet product dispensers useful in the reduction of waste. 
       BACKGROUND 
       [0003]    Sheet product dispensers typically include rolls of sheet product. The sheet product is dispensed from the roll by passing one end of the sheet product through a pair of rollers. One of the rollers is coupled to an electric motor that is selectively energized by a controller. Friction between the rollers and the sheet product pulls the sheet product from the sheet product roll when the motor is operated. 
         [0004]    Waste reduction is an important consideration in the design and use of dispensers. One way to reduce waste is to ensure the full contents of a roll are used. To achieve this goal, some dispensers include a means to support two or more rolls of rolled sheet product. One such known dispenser is able to receive two rolls, the left ends of which are substantially aligned in a plane, and the right ends of the rolls are substantially aligned in another plane. Once the roll in the foremost position is depleted, product from the roll in the secondary position may be taken by users. 
         [0005]    To satisfy customer desires, some dispensers provide a means of conveying product from a roll to a user. One dispenser is able to receive two full-sized rolls and ends of the rolls are non-planar. The rolls are substantially coaxial and side-by-side. Since the ends of the rolls are not substantially planar, this dispenser requires a separate drive roller and pinch roller for each roll in order to convey product to a user. 
         [0006]    Other bath tissue or toilet paper sheet product dispensers can receive two full-sized rolls, the ends of which are aligned in planes so that the dispenser only requires one drive roller to dispense product from either roll, thereby reducing the number of dispenser components required to convey product to a user. However, while only a single drive roller is required, this dispenser requires two pinch rollers in order to convey product to a user because the substrate is less robust. 
         [0007]    Other dispensers, known as “stub roll dispensers,” can receive one full-sized roll and one partially-depleted roll. One known stub roll dispenser aligns the ends of the rolls in planes and conveys product to a user. This dispenser further reduces the number of dispenser components required to convey product to a user, as it utilizes only one drive roller and only one pinch roller. Since the rolls in this dispenser are arranged vertically, it also reduces the amount of horizontal wall space required for installation. However, use of this type of dispenser demonstrates the need for additional waste reduction. For example, stub roll dispensers are configured to accommodate roll lengths that are a small fraction (e.g. 25% or less) of the original roll length. Therefore, if the stub roll is too large to fit into the stub roll position at the time of servicing, the custodian must either place the stub roll outside of the dispenser cabinet, which is undesirable for both aesthetic and safety reasons, discard the roll or must choose to not service the dispenser. In a washroom with one known stub roll dispenser, removing the stub roll from the dispenser and replacing it with a full sized roll is desirable to prevent the dispenser from running empty of sheet product before the next service cycle. 
         [0008]    Historically, the need to reduce waste has focused research and design efforts on increasing the capacity of the full-sized roll. This effort has been unsuccessful, at least in part because this method does nothing to reduce waste due to premature discarding of a stub roll. 
       SUMMARY 
       [0009]    The terms “invention,” “the invention,” “this invention” and “the present invention” used in this patent are intended to refer broadly to all of the subject matter of this patent and the patent claims below. Statements containing these terms should not be understood to limit the subject matter described herein or to limit the meaning or scope of the patent claims below. Embodiments of the invention covered by this patent are defined by the claims below, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire specification of this patent, all drawings and each claim. 
         [0010]    A method of reducing sheet product waste generated during use of a sheet product dispenser in a particular location and over a broad range of usage rates includes designing a dispenser, the design including: determining a desired housing size to obtain a top to bottom height for sheet product roll storage within the housing, dividing the height by two to obtain a maximum roll diameter, and locating two roll holders in the housing so that each holder may accept a roll having the maximum roll diameter, positioning a first roll of the maximum roll diameter in a first one of the two roll holders; and positioning a second roll of the maximum roll diameter in a second one of the two roll holders, so that two rolls of equivalent length are configured to be dispensed sequentially from the dispenser. The installation and use of two rolls of maximum roll diameter reduces waste. 
         [0011]    Another method of reducing sheet product waste generated during use of a sheet product dispenser includes: determining the maximum desired capacity of sheet product for a dispenser of a given size; determining the sheet product maximum roll diameter required to provide half of the maximum desired length of sheet product per service cycle; providing a dispenser for the sheet product comprising: space for two rolls of sheet product, each of the maximum roll diameter, two sets of sheet product roll holders, each positioned to accept a roll having the desired maximum roll diameter, a means to dispense the sheet product out of the dispenser, and a means to enable sheet product to be dispensed sequentially from one roll then from the second roll; positioning a first sheet product roll of the desired roll length in a first one of the two sets of sheet product roll holders in the dispenser; and positioning a second sheet product roll of the desire roll length in a second one of the two sets of sheet product roll holders in the dispenser. 
         [0012]    A dispenser for rolled sheet product may be formed according to the methods described above. The dispenser may include: space for two substantially identical rolls of sheet product; two sets of sheet product roll holders, each positioned to accept a roll substantially the same diameter, with one roll positioned above the other; one mechanism to dispense sheet. product from the dispenser; and a means to enable sheet product to be dispensed sequentially from one roll then from the second roll. 
         [0013]    Another sheet towel roll dispenser may be formed according to the methods described above and may include: two sets of sheet towel roll holders, wherein (i) one set is in a position in the dispenser that is large enough to accept a full-sized roll, and (ii) the other set is in a position in the dispenser that is large enough to accept a roll at least 67% as long as, but not substantially larger than, the full-sized roll, (b) one drive roller, substantially the same length as a roll of towel, and (c) one pinch roller, substantially the same length as a roll of towel. 
         [0014]    The dispenser may dispense sheet towel product from a roll in a primary position in the dispenser before dispensing from a roll in a secondary position in the dispenser. Either sheet towel roll holder in one set may be substantially planar to a corresponding sheet towel roll holder in the other set. Alternatively, the ends of the drive roller may be substantially planar to either sheet towel roll holder in a set. 
         [0015]    A sheet product dispenser formed according to one of the above methods may include: (a) two sets of sheet product roll holders, wherein (i) one set is in a position in the dispenser that is large enough to accept a full-sized roll, and (ii) the other set is in a position in the dispenser that is large enough to accept a roll at least 67% as long as, but not substantially larger than, the full-sized roll, (b) one drive roller, substantially the same axial length as a roll of product, and (c) one pinch roller, substantially the same axial length as a roll of product. 
         [0016]    The dispenser may dispense product from a roll in a primary position in the dispenser before dispensing from a roll in a secondary position in the dispenser. Either sheet product roll holder in one set may be substantially planar to a corresponding sheet product roll holder in the other set. Alternatively, the ends of the drive roller are substantially planar to either sheet product roll holder in a set. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    Illustrative embodiments of the present invention are described in detail below with reference to the following drawing figures: 
           [0018]      FIG. 1  is an illustration of towel consumption as a function of usage rate. 
           [0019]      FIG. 2  is an illustration of the comparison between a dispenser having a stub roll in use and a dispenser with a stub roll not in use. 
           [0020]      FIG. 3  is an illustration of towel consumption using an embodiment according to the present invention. 
           [0021]      FIG. 4  is an illustration of an example of waste at various percentages of stub roll size to primary roll size. 
           [0022]      FIG. 5  is an illustration of the waste savings when using two 536 foot initial rolls versus a 1000 foot primary roll. 
           [0023]      FIG. 6  is a perspective view of a sheet product dispenser in accordance with an embodiment of the present invention. 
           [0024]      FIG. 7  is a perspective view of the sheet product dispenser of  FIG. 6  with the front cover removed. 
           [0025]      FIG. 8  is a side plan view of the sheet product dispenser of  FIG. 6  with the front cover removed. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    The subject matter of embodiments of the present invention is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described. 
         [0027]    Embodiments of this invention include a system and method for minimizing waste over a broad range of usage rates. Embodiments of this invention may be used with the dispenser described in US 2010/0286818, which is hereby incorporated by reference in its entirety. 
         [0028]    In particular, as shown in  FIGS. 6-8 , one embodiment of a sheet product dispenser  20  includes a front cover  22  and a back plate  24  that is arranged to hold and dispense a sheet product  26 . The dispensing mechanism may include a transfer bar  60  that is activated by an actuator. The transfer bar acts to move the end portion of sheet product  26  on main roll  72  from a first position to a second position where it engages the rollers in roller assembly  74  and may thereafter be dispensed. Two sheet product rolls  70 ,  72  are mounted on rolls or core stock. Maintenance personnel manually refill the sheet product dispenser  20  and position the second roll  70  within the lower or tapered portion  30 . This second roll  70  may be a stub roll since it usually, but not necessarily, contains only a portion of the sheet product of a new/full sheet product roll. However, in one embodiment the stub roll  70  can be a new or full sheet product roll. The stub roll  70  feeds sheet product to a roller assembly  74  that includes a pair of rollers that pull the sheet product when activated by the motor. 
         [0029]    After the roller assembly  74  pulls the sheet product from either the stub roll  70  or the main roll  72 , the sheet product proceeds to the tear bar assembly. The tear bar assembly is positioned adjacent the dispensing slot  32 . A means for cutting the sheet product  26  is included in the tear bar assembly once the appropriate amount of sheet product  26  has been dispensed. The tear bar assembly may separate the dispensed sheet product using a sharp edge that cuts into the sheet when the user pulls the dispensed sheet product  26 . The separation of the sheet product  26  from the sheet product roll  70 ,  72  may then be used and discarded as necessary by the user. 
         [0030]    In this embodiment, the stub roll  70  and main roll  72  are arranged with the main roll  72  being in the upper portion and the stub roll  70  in the lower portion of sheet product dispenser  20 . The roller assembly  74  includes a feed roller  86  and a pinch roller  88 . The location where the rollers meet is commonly referred to as the “nip.” The feed roller  86  is coupled for rotation to the motor. When maintenance or refill operations are performed on the sheet product dispenser  20 , the stub roll  70  is positioned in the lower portion and the leading edge portion  90  of the sheet product  26  from stub roll  70  is inserted between the feed roller  86  and the pinch roller  88  at the nip. Friction between the rollers  86  and  88  and the sheet product  26  causes sheet product  26  to be pulled from the stub roll  70  when the motor is activated. Maintenance personnel may also position the main roll  72  in the sheet product dispenser  20 . The main roll  72  includes a leading edge portion  90  that is positioned adjacent the transfer bar  60 . An arm on the transfer bar  60  extends parallel to the feed roller  86  transversely across the front of the sheet product dispenser  20  to engage the main roll leading edge portion  90 . 
         [0031]      FIG. 1  illustrates towel consumption as a function of usage rate. Towel consumption is the sum of towel usage and towel waste. Specifically,  FIG. 1  compares consumption over a range of usage rates. Usage rate refers to the amount of towel used in linear feet per service cycle. A service cycle is the period of time between custodian visits for review and restocking. As shown in  FIG. 1 , the general profile of the traces remains constant, regardless of the roll footage. Increasing the roll length simply moves the trace to the right on the plot. The roll length that yields the least waste depends on which towel usage rate is in effect. Generally, users prefer rolls having higher capacity. 
         [0032]      FIG. 2  illustrates the comparison between a dispenser having a stub roll in use and a dispenser having a stub roll not in use. Unexpectedly, the traces are almost overlapping, with only minor variance. Thus, the stub roll feature provides little advantage for minimizing waste. 
         [0033]      FIG. 3  illustrates towel consumption using an embodiment of this invention. A dispenser of an embodiment of this invention offers minimal waste over a wider range of towel usage rates and provides a high capacity dispenser. 
         [0034]      FIG. 4  illustrates an example of waste at various percentages of stub roll size to primary roll size. In  FIG. 4 , the primary roll size is 1000 feet. The consumption for each of six stub roll sizes as a percentage of the primary roll length is illustrated. 
         [0035]    In one embodiment of this invention, the stub roll length is increased to 67% as long as a full sized roll. Compared to a stub roll length that is 50% as long as a full sized roll, increasing the stub roll length to 67% as long as a full-sized roll substantially reduces waste due to premature discarding. This is true even if two smaller sized rolls of equal length must be used. In another embodiment of this invention, the stub roll length is increased in size to 100% of the length of a full-sized roll. In this embodiment, towel waste due to premature discarding of the roll is further reduced. This reduction occurs even if a full-sized roll must to decrease in length to make room for both rolls within a dispenser design. 
         [0036]    Thus, a system and method of reducing waste utilizing a dispenser capable of receiving two rolls of substantially equal size can reduce the occurrence of waste. In one embodiment, two identically sized rolls are used in a dispenser. Partially used rolls may be moved to the stub roll position to allow installation of a full-sized roll in the primary roll position. By way of example,  FIG. 5  illustrates the waste savings when using two 536 foot initial rolls versus a 1000 foot primary roll. 
         [0037]    Infrequently, a high usage rate may require entirely discarding a partially used roll to make sure the dispenser does not run empty prior to the next service cycle. As shown in  FIG. 4 , the closer the two rolls are in size for a given dispenser size, the less waste is generated by premature discarding. The closer the stub roll capacity is to the length of the primary roll, the better chance there is for use of the stub roll. 
         [0038]    Embodiments of this invention include a drive roller comprising a cylinder that may rotate and communicate with rolled sheet product in order to convey the sheet product from inside of the dispenser housing to the outside of the dispenser housing. A drive roller may rotate once, more than once, or less than once in order to deliver an appropriate length of sheet product for a user. In other embodiments, a drive roller may be of a shape other than a cylinder. In other embodiments, a drive roller may include a feature such as a cutting knife or a tear blade. In one embodiment, the drive roller is substantially the same axial length as the axial length of a roll of product. 
         [0039]    Embodiments of this invention include a pinch roller comprising a cylinder that may rotate and communicate with rolled sheet product in order to cause the sheet product to touch the drive roller, thereby enabling the drive roller to convey product to a user. In other embodiments, a drive roller may be of a shape other than a cylinder. In other embodiments, a drive roller may be non-rotational. 
         [0040]    In one embodiment, two full-sized sheet product rolls have the same length and diameter, and both sets of sheet product roll holders are positioned in the dispenser with enough room so that each set of sheet product roll holders may simultaneously receive a full-sized roll of product. However, manufacturing tolerances, premature usage, etc., may cause differences in length and diameter between two full-sized rolls. 
         [0041]    Practical design considerations as well as customer preferences may affect some embodiments. For example, one set of roll holders may be positioned in the dispenser without sufficient room to receive a completely full-sized roll, but that can accommodate a roll that is at least 67% as long as a full-sized roll. In that case, a full size roll and the smaller roll may be used. 
         [0042]    In one embodiment, the web paths for each of the primary and the stub rolls traverse the same components. In this manner, a dispenser can be made smaller, simpler, and less expensive, such as by using only one drive roller, pinchroller, paper chute, etc. to dispense from either of the rolls of product. Horizontal space on a wall may be limited in a washroom environment, and that in many embodiments, a narrow, taller dispenser with two full-sized rolls arranged vertically is more useful than a short, wide dispenser with two similar-sized rolls arranged side-by-side. 
         [0043]    Different arrangements of the components depicted in the drawings or described above, as well as components and steps not shown or described are possible. Similarly, some features and subcombinations are useful and may be employed without reference to other features and subcombinations. Embodiments of the invention have been described for illustrative and not restrictive purposes, and alternative embodiments will become apparent to readers of this patent. Accordingly, the present invention is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications can be made without departing from the scope of the claims below.