Abstract:
The present invention provides an apparatus for dispensing rolled sheet material, the apparatus including a housing that defines an interior adapted to rotatably support rolled sheet material and having a dispensing opening sized to allow sheet material to be dispensed therefrom. The apparatus further includes a floating nip within the housing such as, for example, may be formed by first and second rollers. The floating nip minimizes variation in the force required to remove sheet material from the dispenser that may result from a user changing the angle at which sheet material is removed.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     No-touch dispensers, i.e., dispensers that do not require the patron to touch any part of the dispenser, are desired for many reasons. No-touch dispensing reduces the chance of transferring disease-causing bacteria, viruses and other microorganisms. No-touch dispensing also makes the process of obtaining a sheet simpler and quicker.  
         [0002]     Single-sheet dispensers, i.e., dispensers that dispense a consistent, fixed quantity of sheet material, are also desired for many reasons. They tend to reduce the quantity of sheet material used by an individual patron, thereby saving on material costs, disposal costs, and costs associated with the frequency whereby the dispensers must be refilled.  
         [0003]     No-touch, single-sheet dispensers for folded, interleaved sheets are known, however the manufacturing processes associated with providing the folded, interleaved sheets are more expensive and complex than the process associated with providing roll products. No-touch, single-sheet dispensers utilizing knives or other cutting devices to cut sheet material from a roll of sheet material are known, but knives and other cutting devices may present a danger to either a patron or an individual refilling the dispenser. No-touch, single-sheet dispensers for rolled products via zones of weakness are known, but if the sheet material tears before the next zone of weakness emerges from the dispenser, the next patron has no sheet material to grasp.  
         [0004]     No-touch, single-sheet dispensing of double rolled products via offset zones of weakness is known, but dispensers for these products still have disadvantages that have yet to be overcome. As an example, many of the prior art dispensers have the disadvantage that the force necessary to dispense the product can vary depending on the angle at which a user of the product pulls on the exposed product. If the applied force is too low, the zones of weakness may not separate, causing more than one sheet to be removed from the dispenser. If the applied force is too high, the zones of weakness may separate prematurely or the product may break at a location other than at the next successive zone of weakness. The features of the dispenser disclosed herein overcome these and other disadvantages of prior art dispensers.  
       SUMMARY OF THE INVENTION  
       [0005]     The aforesaid needs are fulfilled and the problems experienced by those skilled in the art overcome by the apparatus for dispensing rolled sheet material of the present invention. In one embodiment, the apparatus includes a housing defining an interior adapted to rotatably support rolled sheet material, the housing further defining a dispensing opening sized to allow sheet material to be dispensed therefrom. The apparatus further includes a floating nip within the housing, the floating nip positioned to restrain sheet material dispensed from the dispensing opening.  
         [0006]     In one aspect of the invention, the floating nip includes a first nipping member that includes a curved surface and a second nipping member that includes a substantially planar surface. Desirably, the first nipping member is biased towards the second nipping member and the second nipping member is biased towards the first nipping member in such a way that the curved surface impinges the substantially flat surface to nip sheet material being dispensed. Desirably, the curved surface has a radius of curvature smaller than about 5 millimeters. More desirably, the curved surface has a radius of curvature smaller than about 2 millimeters.  
         [0007]     The first nipping member may further include first and second arms. The first and second arms are desirably rotatable about first and second torsion springs. The first and second torsion springs bias the curved surface of the first nipping member towards the substantially flat surface of the second nipping member. The first nipping member is desirably rotatable within the housing about the third and fourth torsion springs through an angle greater than about 15 degrees, even more desirably through an angle greater than about 30 degrees.  
         [0008]     The second nipping member is desirably rotatable about third and fourth torsion springs. The third and fourth torsion springs bias the substantially flat surface of the second nipping member towards the curved surface of the first nipping member.  
         [0009]     Desirably, the torsion springs are sized to provide a pressure and/or level of friction in the nip low enough to allow sheet material to be withdrawn from the housing without breaking the sheet material and high enough to allow lines of weakness in the sheet material to break after the lines of weakness emerge from the nip during dispensing. Additionally, the position of the floating nip desirably self-adjusts to accommodate a change in the angle at which sheet material is withdrawn from the dispensing opening. Self-adjustment of the floating nip reduces variation in the nip pressure and/or withdrawal friction, thereby reducing the variation in the magnitude of the force necessary to remove sheet material from the dispenser.  
         [0010]     In another aspect of the invention, the floating nip may include at least one roller. Desirably the nip is pressurized. Even more desirably, the nip is pressurized by at least one spring.  
         [0011]     In another embodiment, the apparatus for dispensing rolled sheet material includes a housing defining an interior adapted to rotatably support rolled sheet material and having a dispensing opening sized to allow sheet material to be dispensed therefrom, a roll of sheet material having a plurality of zones of weakness that substantially extend across the width of the sheet material, and a pivotable nip within the housing. The nip includes a first nip member and a second nip member, the first nip member being resiliently biased against the second nip member, and the second nip member being resiliently biased against the first nip member. The sheet material is dispensed along a path that extends from the roll of sheet material, through the pivotable nip, and through the dispensing opening. Desirably, the rolled sheet material comprises inner and outer layers of sheet material, the layers of sheet material comprising a plurality of offset zones of weakness that substantially extend across the width of the sheet material.  
         [0012]     In one aspect, the pivotable nip is movable to accommodate changes in the angle at which the sheet material is withdrawn from the dispensing opening. The nip pivots so that the orientation of the sheet material within the nip does not substantially change despite changes in the angle at which a user withdraws sheet material from the dispenser.  
         [0013]     Other features and aspects of the present invention are discussed in greater detail below. 
     
    
     BRIEF DESCRIPTIONS OF THE DRAWINGS  
       [0014]      FIG. 1  is a perspective view depicting the interior of a dispenser of the present invention;  
         [0015]      FIG. 2  is a partial cross-sectional diagrammatic view of the dispenser of  FIG. 1 ;  
         [0016]      FIGS. 3 &amp; 4  are operational cross-sectional diagrammatic views of the dispenser of  FIG. 1 ; and  
         [0017]      FIG. 5  shows a plan view of a roll of sheet material. 
     
    
     DETAILED DESCRIPTION  
       [0018]     Reference will now be made in detail to the various embodiments of the invention, one or more examples of which are illustrated in the drawings. Each embodiment is provided by way of explanation of the invention and is not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment or figure can be used on another embodiment or figure to yield yet another embodiment. It is intended that the present invention include such modifications and variations.  
         [0019]     The present invention provides an apparatus for dispensing rolled sheet material. Exemplary sheet materials for which the present invention is suitable include, but are not limited to, absorbent sheet materials such as towels, wipers, tissue, and so forth. Suitable sheet materials are disclosed, by way of non-limiting examples only, in U.S. Pat. No. 5,048,589 to Cook et al., U.S. Pat. No. 5,399,412 to Sudall et al., U.S. Pat. No. 5,674,590 to Anderson et al., U.S. Pat. No. 5,772,845 to Farrington, Jr. et al., U.S. Pat. No. 5,904,971 to Anderson et al., U.S. Pat. No. 6,248,212 to Anderson et al., and U.S. Pat. No. 6,273,996 to Hollenberg et al., the entire contents of which are incorporated herein by reference. The sheet materials for which the present invention is suitable are desirably wound around a core, yet may, for other embodiments, be coreless. The sheet materials for which the present invention is suitable desirably have regularly spaced zones of weakness extending substantially across the width of the sheet material. The zones of weakness are used to separate the sheet material into individual sheets and may be, for example, defined by a series of perforations. The sheet material having regularly spaced zones of weakness substantially extending across its width is desirably double wound into a roll having inner and outer layers of sheet material wherein the zones of weakness for the inner and outer layers are offset as is taught in U.S. Pat. No. 3,770,172 to Nystrand, incorporated herein by reference in its entirety. The use of double-wound sheet material having offset zones of weakness allows the sheet material to tear within the dispenser while still providing a tail of sheet material extending from the dispenser to be grasped by the next patron.  
         [0020]      FIG. 5  shows a roll of sheet material  1  that has been unwound slightly from its outer surface to show the offset perforation arrangement. The roll  1  comprises an inner web  2  and an outer web  3  each having perforations  4  which allow individual sheets  5  to be detached from the webs. The individual sheets have a length X. The offset of the perforations is shown as length Y, and in this embodiment has an offset of about 50/50.  
         [0021]     It is envisioned that any suitable amount of offset may be used for the webs. The offset can be expressed in terms of a ratio of percentages; the ratio must total 100, the sum of both lengths totaling the whole length of one sheet. Desirably, the offset ratio is less than about 70/30, and more desirably the ratio is less than about 60/40. Even more desirably, the offset is about 50/50, with each sheet being presented in an amount equal to that of the previous and the subsequent sheets. However, any offset in the range between about 50/50 and about 70/30 has been found to work adequately.  
         [0022]     If there is an uneven offset present, it is desirable that the outer web projects more once a sheet has been detached from the inner web than the inner web projects when a sheet has been detached from the outer web. When the outer web is pulled from the roll and out of the dispenser, it will almost certainly pull the inner one with it because of the way the webs are wound up. Conversely, when the inner web is pulled, the certainty that the outer web will be pulled out is less because the inner web does not surround the outer web; more reliance is placed on the friction or other attachment between the two webs to pull the outer web from the dispenser. Therefore, it is desirable that the outer web projects by a greater amount than the inner web each time so that there is more chance that the outer web will be drawn through the dispenser with the inner web.  
         [0023]     Embodiments of a dispenser  10  incorporating basic operational features according to the present invention are illustrated in  FIGS. 1-4 . The dispenser  10  is configured to dispense a primary roll  12  of web material  14  that may be, for example, a standard eight-inch towel roll. For illustrative purposes only, the roll  12  will be referred to as a towel roll and the web material will be referred to as towel material.  
         [0024]     Referring to  FIG. 1 , the dispenser  10  includes a housing  18  of any general shape and configuration. The housing  18  includes a bottom portion  20 , a front portion  22 , a back portion  24 , and side portions  26 . The dispenser  10  may be mounted to a vertical supporting wall structure by any conventional means. A dispensing slot  28  is defined at an appropriate location in the housing  18 . In the illustrated embodiment, the dispensing slot  28  is provided in the bottom portion  20 . It should be understood that the dispensing slot  28  may be disposed at various locations in the housing depending on the conveying path of the towel material  14  and configuration of the internal components of the dispenser  10 . The dispensing slot  28  is desirably disposed so that a user can see a tail  16  of the towel material extending therefrom and has easy access to grasp and pull the tail.  
         [0025]     It should be appreciated that the dispenser  10  according to the invention is not limited in its construction by any particular type of materials. For example, the back portion  24  and/or bottom portion  20  may be formed as a sheet metal assembly and the front portion  22  may comprise a removable or pivotal plastic assembly.  
         [0026]     The roll  12  is rotatably disposed in the housing  18  by any manner of suitable carrier, such as side arms  30 . Various configurations of carrier mechanisms are known in the art for rotatably supporting a roll of material in a dispenser, and any such device may be used with the present invention.  
         [0027]     Optionally, there may be a window defined in the housing to allow viewing of the interior of the dispenser. The window may be open, or may be constructed of a transparent or translucent material that permits viewing of the interior of the dispenser.  
         [0028]     Referring to  FIGS. 2-4 , within the housing  18  is a floating nip  32 . The floating nip  32  has an entrance side  34  and an exit side  36 . As the towel material  14  is dispensed, the towel material enters the floating nip  32  on the entrance side  34  and exits on the exit side  36  before traveling through the dispensing slot  28 . The nip  32  is formed between first and second nipping members  40 ,  50 . Desirably, the floating nip  32  has a length approximately equal to the width of the towel material  14  being dispensed. However, the nip  32  may be interrupted by first and/or second recessed portions  49 ,  54  in the first and/or second nipping members  40 ,  50  respectively (see  FIG. 1 ). The recessed portions  49 ,  54  allow a user to grasp towel material  14  on the entrance side  34  of the floating nip  32  in the event there is no tail extending from the dispensing opening  28 .  
         [0029]     The nipping members  40 ,  50  are biased and/or pressurized against one another. As depicted in the figures, the first nipping member  40  rotates about and is biased by at least one first torsion spring  42 . The second nipping member  50  rotates about and is biased by at least one second torsion spring  52 . Desirably, first and second nipping members  40 ,  50  are each biased by two torsion springs to provide substantially equal force within the floating nip  32  from one end of the nip to the opposite end. Alternatively, other mechanisms known to those skilled in the art may be used for biasing or pressurizing the first nip member  40  and the second nip member  50  against one another.  
         [0030]     The magnitude of the force exerted by the first nip member  40  against the second nip member  50  is desirably such that the tension required to pull the towel material  14  through the floating nip  32  exceeds the breaking strength of zones of weakness in the towel material. However, the tension required to pull the towel material  14  through the floating nip  32  desirably does not exceed the breaking strength of the towel material  14  in areas other than the zone of weakness. Therefore, tension applied to the tail  16  of the towel material  14  extending from the dispensing opening  28  will advance the towel material  14  until a zone of weakness emerges from the floating nip  32 . When the zone of weakness emerges from the floating nip  32 , the zone of weakness will break, providing a single sheet to the patron, and leaving an extended tail of towel material  16  for the next patron to grasp. A detailed description of the desired force balance for dispensing double-wound rolls of offset-perforated sheet material can be found in U.S. Pat. No. 3,770,172 to Nystrand.  
         [0031]     The magnitude of the force required to pull sheet material through a fixed nip can change depending on the angle at which a user pulls the tail from the dispensing opening. For example, if a user pulls on the tail in a more upwardly or downwardly direction, the sheet material may have a larger wrap angle around one of the nipping members. The larger wrap angle creates more friction and results in a greater force being necessary to pull the sheet material through the nip. The floating nip  32  of the present invention is self-adjusting with respect to the angle at which sheet material is withdrawn. Referring to  FIG. 3 , a more upwardly directed force applied to the tail material  16 , depicted by arrow A, causes the first nipping member  40  to rotate upwardly about the first torsion springs  42 . Because the second nip member  50  is biased upwardly towards the first nip member, the sheet material remains clasped within the nip and remains properly oriented while traveling through and beyond the nip. Conversely, referring to  FIG. 4 , a more downwardly directed force, depicted by arrow B, causes the second nipping member  50  to rotate downwardly about the second torsion springs  52 . Because the first nipping member  40  is biased towards the second nipping member  50 , the sheet material remains clasped within the nip  32  and is removed from the nip at the desired angle. Because the towel material  14  is removed at the desired angle with respect to the floating nip  32 , the tension required to dispense the towel material remains consistent and results in more consistent dispensing performance.  
         [0032]     Referring again to  FIG. 1 , the second nipping member  50  includes a nipping surface  56 . The nipping surface  56  nips the towel material  14  against the first nipping member  40  during dispensing of sheet material. Desirably the nipping surface  56  is substantially flat and/or planar to provide a relatively large surface area for the first nipping member  40  to impinge against. Therefore, as the floating nip  32  moves to adjust for changes in the dispensing angle of the towel material  14 , slight lateral movement of the first nipping member  40  with respect to the second nipping member  50  will not cause the first and second nipping members to disengage. Disengagement of the nipping members  40 ,  50  is to be avoided, as disengagement will degrade dispensing performance.  
         [0033]     The first nipping member  40  desirably includes a rounded end  48  that impinges against the nipping surface  56  of the second nipping member  50 . The rounded end  48  provides a curved surface that minimizes the surface area of the first nipping member  40  that contacts the towel material  14  passing through the floating nip  32 . Desirably, the curved surface has a radius of curvature smaller than about 5 millimeters. More desirably, the curved surface has a radius of curvature smaller than about 2 millimeters. Desirably, the rounded end  48  does not provide a sharp edge upon which sheet material could catch or tear. Therefore, the curved surface desirably has a radius of curvature greater than about 0.1 millimeters.  
         [0034]     The rounded end  48  is desirably disposed on an extension member  46  that is disposed on arms  44 . The arms  44  are biased as described above by the torsion springs  42 . The extension member  46  is disposed approximately perpendicular to the arms  44 . Such positioning minimizes the potential for deflection of the extension member  46  caused by the biasing against the second nipping member  50 . The extension member  46  may be curved to allow the first nipping member  40  more rotational freedom about the torsion springs  42  without causing the extension member to contact the interior of the housing  18 . During the dispensing operation, the first nipping member  40  is desirably rotatable within the housing about the torsion springs  42  through an angle greater than about 15 degrees, even more desirably through an angle greater than about 30 degrees. Greater rotational freedom of the nipping members  40 ,  50  permits the floating nip  32  to accommodate a greater range of dispensing angles.  
         [0035]     The arms  44  extend towards the back portion  24  of the dispenser  10 . Desirably, the arms are long enough such that rotation of the first nipping member  40  about the torsion springs  42  can be accomplished within the housing  18  without opening the housing. Therefore, in the event that the towel material  14  were to tear on the entry side  34  of the nip  32 , the user may open the nip by raising the first nipping member  40  without opening the housing  18 . The towel material  14  within the dispenser  10  may therefore be easily rethreaded through the floating nip  32 .  
         [0036]     The first and second nipping members as shown in the figures may be repositioned within the dispenser. For example, the nipping members  40 ,  50  may be positioned within the dispenser in a side-by side orientation. As another example, the first nipping member  40  may be positioned below the second nipping member  50 . Therefore, the particular orientation of the nipping members within the dispenser is not critical to the performance, so long as the floating nip  32  is positioned in the path of the dispensing towel material  14  and is capable of elf-adjustment to minimize the effect of changes in the angle at which a user dispenses the towel material.  
         [0037]     While the invention has been described in detail with respect to specific embodiments thereof, it will be apparent to those skilled in the art that various alterations, modifications and other changes may be made without departing from the spirit and scope of the present invention. It is therefore intended that all such modifications, alterations and other changes be encompassed by the claims.