Abstract:
The present invention provides a dispenser for folded sheets having an overfill prevention device, which effectively prevents the dispenser from being overfilled with folded sheet material. The result of the present invention is that a maintainer of the dispenser will have a difficult time overfilling the dispenser.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally relates to a folded sheet dispenser, in particular to a folded sheet dispenser with an overfill prevention device. 
       BACKGROUND OF THE INVENTION 
       [0002]    Dispensers of sheet products in roll form are simple and reliable because the rolls are easy to load and the dispensers are very difficult to overload or overstuff. However, products in roll form present some dispensing problems. A single roll dispenser with a nearly depleted roll must be monitored carefully by maintenance personnel to avoid running out at an inconvenient moment. Changing a partially depleted roll results in wasted product. Moreover, some single roll dispensers are designed so a roll cannot be removed until it is depleted and only a core is left. 
         [0003]    Dispensers for dispensing stacked folded sheets of paper towels and the like are well known in the art. Single sheet dispensers are generally desirable because they can be refilled when only partially depleted, as compared to roll product dispensers wherein changing a partially depleted roll may result in significant wasted product. Stacked single sheet dispensers are also desirable because they tend to be simple devices that are not subject to jamming or failure. 
         [0004]    A disadvantage of folded stacked sheet dispensers is that they are susceptible to attempts at being overfilled or “stuffed.” Overfilling the dispenser can compress the stack of sheets and make it very difficult to remove a sheet from the dispenser. For example, the pressure against the stack may prevent a free tab or end of the sheet from becoming accessible for a user to grasp in order to withdraw the sheet. In an overfilled condition, the stack of sheets may be wedged in the dispenser so firmly that the portion of the sheet grasped by the user simply tears instead of dispensing the sheet. Friction against the dispensing opening may be increased by overfilling the dispenser making dispensing unreliable and problematic. 
         [0005]    There is still a need in the art for improvements in stacked folded sheet dispensers for preventing overfill conditions. The present invention relates to such an improved dispenser. 
       SUMMARY OF THE INVENTION 
       [0006]    Generally stated, the present invention provides a folded sheet dispenser with a simple, but effective overfill prevention device. 
         [0007]    In one embodiment of the present invention, the present invention provides a folded sheet dispenser having
       a. a mounting frame adapted to hold a stack of folded sheets, the mounting frame including a back panel, a bottom portion and a top portion;   b. a cover connected to the mounting frame, the cover having an inside surface which faces the mounting frame and an exterior surface forming the front of the dispenser, the cover having at least one projection extending from the inside surface;   c. a dispensing opening located at or near the bottom portion of the mounting frame;   d. an overfill prevention device located at or near the top portion of the mounting frame, said overfill prevention device comprises
           i. a bracket having a first section which is pivotally connected to a housing and an opposite second section, said second section being free to rotate in an arc about the pivotally connected first section, the bracket has a filling position and a dispensing position, wherein the bracket is adapted to contact a stack of folded sheets, when the dispenser is filled with a stack of folded sheets;   ii. a locking element which engages the bracket and holds the bracket in the filling position when the cover of the dispenser is open and releases the bracket when the cover of the dispenser is closed; and   
               
 
         [0014]    wherein the projection on the cover engages the locking element as the cover is being closed such that the locking element releases the bracket to allow the bracket to move to the dispensing position. 
         [0015]    In a further embodiment of the present invention, the locking element is a plate. The plate has a first end and an opposite second end. In addition, the plate is connected to the mounting frame with a pivot connection at or near the first end of the plate and the opposite second end of the plate is free to move in an arc about the pivot connection. Typically, the second end of the plate engages the bracket, retaining the bracket in the filling position when the cover is open. In one aspect of the present invention, the plate engages the bracket using the force of gravity. 
         [0016]    In an additional embodiment of the present invention, the bracket has an upper portion and a lower portion. The lower portion is adapted to contact the stack of folded sheets in the dispenser and the upper portion is adapted to be engaged with the locking element. 
         [0017]    In another embodiment of the present invention, the upper portion of the bracket further has at least one slot. This slot is positioned at or near where the locking element engages the bracket. The slot is configured to allow the protrusion on the cover to engage the lock element without engaging the bracket. 
         [0018]    In yet another embodiment of the present invention, the overfill prevention device further has a housing. This housing comprises at least one opening, such that the opening is positioned in the housing to allow the projection on the cover to contact the locking element. 
         [0019]    By providing the folded towel dispenser of the present invention, drawbacks of the conventional overfill prevention devices can be overcome 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  shows a exploded perspective view of the dispenser within the scope present invention. 
           [0021]      FIG. 2  shows a front perspective view of a overfill prevention device within the scope of the present invention. 
           [0022]      FIG. 3  shows a bottom perspective view of a overfill prevention device within the scope of the present invention. 
           [0023]      FIG. 4  shows a exploded perspective view of a overfill prevention device within the scope of the present invention. 
           [0024]      FIG. 5  shows an inside exploded perspective view of a overfill prevention device within the scope of the present invention. 
           [0025]      FIG. 6  shows a cross sectional view of the overfill prevention device within the scope of the present invention in the filling position. 
           [0026]      FIG. 7  shows a cross sectional view of the overfill prevention device within the scope of the present invention converting from the filling position to the dispensing position. 
           [0027]      FIG. 8  shows a cross sectional view of the overfill prevention device with the scope of the present invention in the dispensing position. 
       
    
    
     DEFINITIONS 
       [0028]    It should be noted that, when employed in the present disclosure, the terms “comprises”, “comprising” and other derivatives from the root term “comprise” are intended to be open-ended terms that specify the presence of any stated features, elements, integers, steps, or components, and are not intended to preclude the presence or addition of one or more other features, elements, integers, steps, components, or groups thereof. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a further embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments and examples described herein as coming within the scope and spirit of the invention. 
         [0030]    To gain a better understanding of the present invention, attention is directed to the Figures of the present specification in general. A dispenser  10  is configured to dispense an individual sheet from a stack of folded individual sheets. The dispenser of the present invention is particularly suitable for dispensing paper towels, tissues and other similar products that are available as individual folded sheets from a stack. 
         [0031]    It should also be appreciated that a dispenser  10  according to the invention is not limited in its overall shape, size or configuration shown in the Figures. It should be understood that these particular dispenser shown in the Figure is illustrated merely as an example of embodiments of a dispenser that may incorporate the unique features of the present invention. 
         [0032]    As is shown in  FIG. 1 , the dispenser  10  includes a mounting frame  20  adapted to hold a stack of folded sheets (not shown in  FIG. 1 ). The mounting frame  20  has a bottom portion  21  and a top portion  22 , with a bottom panel  29  optionally having a dispensing opening  30  located at or near the bottom portion  21  of the mounting frame  20 . The bottom panel  29  may be a separate component from the mounting frame  20  and joined to the mounting frame  20  using suitable means, such as adhesives, welding or mechanical fasteners. Alternatively, the bottom panel  29  may be formed integrally with the mounting plate  20 , such that the mounting plate  20  and bottom panel  29  are one single piece. The mounting frame  20  also includes a back panel  24 , and may have two side walls  27  and  28 . The bottom panel  29  along with the back panel  24  and side walls  27  and  28 , if present, create a storage space  26  that allows the mounting frame  20  to hold the stack of folded articles. 
         [0033]    The mounting frame  20  is typically mounted to a support surface, such as a wall or the like, which serves to hold the dispenser  10  on the support surface. As such, the back panel  24  may be provided with various mounting means, such as pre-formed holes  25 , as is shown in  FIG. 1 , which mechanical fasteners may be used to fasten the mounting frame to the support surface. Other suitable mounting means may also be used. 
         [0034]    Referring to both  FIGS. 1 and 5 , the dispenser  10  further has a cover  40  which is movably attached to the mounting frame  20 . The cover may have side panels  47 , a front panel and interior surface  44  and an exterior surface  42 . As shown in  FIGS. 1 and 5 , the cover  40  may be attached to the back part of the mounting frame  20 , for example to the bottom panel  29  or the side walls  27 ,  28 , and is movable from a closed position, in which the interior storage space  26  of the dispenser, including the stack of folded sheets cannot be accessed other than through the dispensing opening  30 , to an open position, where easy access is provided to the internal storage space  26  for loading additional folded sheets into the storage space. In its closed position, the cover  40  defines a front panel  48  of the dispenser  10 . The cover  40  is pivotally mounted to the stationary part of the mounting frame  20  by a pivotal mounting mechanism  32  located on the mounting frame  20  with a complementary pivot mounting mechanism  50  located on the inside of the cover  20 , in particular on the side panels  47  of the cover  20 . As an example shown in  FIGS. 1 and 5 , the mounting mechanism  32  is an opening in the bottom panel  29  of the mounting frame  20  and the complementary mounting mechanism  50  on the cover is projection which is sized and shaped to fit into the opening of the mounting mechanism. It should be appreciated that any number of conventional pivotal arrangements are known and may be utilized to pivotally mount the cover  40  to the mounting frame  20  so long as the cover  40  may be easily moved out of the way to access the interior storage space  26  of the dispenser  10 . In addition, the cover  40  may be releasably locked to the mounting frame  20  by any conventional locking device  46  and a complementary lock receiver  34  present on the mounting frame. It should be appreciated that the locking device may be keyed or unkeyed, and that the main purpose of the locking device is to retain the cover  40  in a closed position. 
         [0035]    As is stated above, the dispenser  10  includes at least one dispensing opening  30 . The dispensing opening  30  is how a user accesses folded sheets  12  and how the folded sheets  12  are dispensed from the internal storage space  26 . In the illustrated embodiment shown in  FIG. 1 , the dispensing opening  30  is defined in the bottom panel  29  of the mounting frame. This is not a limitation of the invention. For example, the dispensing opening  30  could also be defined in a bottom portion or panel member of the cover  40 . The dispensing opening  30  may be disposed in any convenient location for a user to pull and dispense the individual folded sheets  12  from the internal storage space  26 . Typically, the dispensing opening  30  is located at or near the bottom portion of the mounting frame and will be generally be located in the bottom panel  29  of the mounting frame  20 . 
         [0036]    A dispenser  10  according to the invention includes an overfill prevention device  60 . The overfill prevention device  60  is configured to be located at or near the top portion of the mounting frame  20  and serves to prevent a service technician from overfilling or stuffing the dispenser with folded sheets  12  to the point where operation of the dispenser is compromised. Generally speaking, the overfill prevention device  60  is actuated by movement of the cover  40 . With the cover  40  closed, as the stack of sheets  12  is depleted, the overfill prevention device automatically moves to a position so as to reduce the internal storage space  26  within the mounting frame  20 . When the cover  24  is opened for refilling the stack, the overfill prevention device  60  is engaged and the available space for refilling the stack is restricted. When the cover  40  is subsequently closed after refilling the supply of stacked sheets  12 , the overfill prevention device  60  is disengaged and any compressive forces acting on the stack of sheets  12  is relieved. 
         [0037]    Referring particularly to  FIGS. 2-4 ,  6 - 8 , an embodiment of the overfill prevention device  60  is shown. The overfill prevention device  60  has a bracket  62  and a locking element  72 . The bracket  62  has a first section  64  which is pivotally connected to a housing  61  and an opposite second section  66 . In addition, the bracket  62  has a lower portion  67  which is adapted to contact the stack of folded sheets  12  in the dispenser  10  and the upper portion  68  which is adapted to be engaged with the locking element. The bracket  62  is adapted to contact a stack of folded sheets  12  in the second section  66  along the lower portion  67  of the bracket  62 , when the dispenser  10  is filled with a stack of folded sheets  12 . As is stated above, the bracket  62  is pivotally connected to the housing. As a result, the second section  66  of the bracket  62  is free to rotate in an arc  65  about the pivotally connected first section  64 , when the locking element  72  is not engaging the bracket  62 , as will be discussed below. This rotation of the bracket  62  results in the bracket  62  having a filling position, shown in  FIG. 6  and a dispensing position, shown in  FIG. 8 . 
         [0038]    The pivotal connection of the bracket  62  to the housing  61  may be achieved through any convention pivotal connection means. As is shown in  FIG. 4 , the pivot connection is an axel  69  extending from the first section  64  of the bracket  62 . A complementary slot  88 , which is adapted to accept the axel  69  of the bracket is located on the housing  61  such that the axel  69  will fit into the slot  88  and that the bracket  62  will rotate in an arc  65 , show in  FIG. 6 , about the pivotal connection created by the axel  69  and the slot  88 . Other conventional pivot connection may be used, other than the one exemplified in the drawings without departing from the scope of the present invention. For example, the bracket could contain the slot and the housing could contain the axel. By having the bracket  62  pivotally connected to the housing  61 , the second section  66  of the bracket  62  is free to move in an arc  65  about the pivotal connection. This will allow the bracket  62  to rotate from the position shown in  FIG. 6  to the position shown in  FIG. 8 , when the cover  40  is closed, which is described in more detail below. 
         [0039]    The locking element  72  is adapted to engage the bracket  62  and serves to hold the bracket  62  in the filling position when the cover  40  of the dispenser  10  is open. In addition, the locking element  72  also releases the bracket  62  when the cover of the dispenser  40  is closed. The locking element  72  will engage the upper portion  68  of the bracket  62 , as is shown in  FIG. 6  and holds the bracket  62  in place, preventing the bracket  62  from being moved by the technician filling the dispenser  10 . This will be described in more detail below. 
         [0040]    The locking element  72  may be a plate  73  as is shown in  FIGS. 5 ,  6  and  7 . Generally, the locking element  72  will have a first end  78  and an opposite second end  79 . In addition the locking element  72  is connected to the housing  61  of the overfill prevention device  60  with a pivot connection at or near the first end  78 . As is shown in  FIG. 4 , the pivot connection is an axel  76  extending from the first end  78  of the locking element. A complementary slot  86 , which is adapted to accept the axel is located on the housing  61  such that the axel  76  will fit into the slot  86  such that the locking element  72  will rotate in an arc  75 , show in  FIG. 6 , about the pivot connection. Other conventional pivot connections may be used, other than the one exemplified in the drawings without departing from the scope of the present invention. For example, the locking element could contain the slot and the housing could contain the axel. By having the locking element  72  pivotally connected to the housing  61 , the opposite second end  79  of the locking element  72  is free to move in an arc  75  about the pivot connection. This will allow the locking element  72  to move out of the way of the bracket  62  when the cover  40  is closed so that the bracket  62  can rotate in the arc  65 , which is described in more detail below. 
         [0041]    The overfill prevention device  60  further has a housing  61 . As described above, the housing  61  serves as pivotal connection points for both the bracket  62  and the locking element  72 . As shown in the drawings, the housing  61  is a separate element from the mounting frame  20 ; however, the housing  61  could be integral with the mounting frame  20 , such that the mounting frame  20  and housing  61  are a single continuous piece. When the housing  61  is a separate element, the housing will generally be provided with a mounting means  81 , which will allow a mechanical fastener to attach the housing  61  to the mounting frame  20 . Additionally, the housing  61  serves to protect both the bracket  62  and the locking element  72  from tampering by a technician loading a stack of folded sheets  12  into the dispenser  10  to override the overfill prevention device. 
         [0042]    Referring to  FIG. 5 , the inside surface  44  of the cover  40  has at least one projection  84  extending away from the inside surface  44  of the cover  40 . The projection(s)  84  on the inside surface  44  of the cover  40  are adapted to engage the locking element  72 , thereby causing the locking element  72  to disengage from contact with the upper portion  68  of the bracket  62 . The projections on the inside of the cover may be integral with the cover (not shown) or may be a separate elements which is held to the inside surface  44  via a suitable fastening means  85 . As shown in  FIG. 5 , the fastening means  85  is a mechanical fastener; however other suitable fastening means, such as adhesive attachment, welding or other similar fastening means may be used. Further, the size and shape of the projections  84  are not critical to the present invention; so long as the projections  84  on the inside cover  44  will contact the locking element  72  and disengage the locking element  72  from the upper portion  68  of the bracket  62 , as the cover of the dispenser is closed. The projections can be cylindrical, cuboidal or other similar shapes, for example. 
         [0043]    The housing  61  of the overfill prevention device  60  further has at least one opening  82 . The opening(s)  82  allow the projections  84  on the inside surface  44  of the cover  40  to contact and engage the locking element  72  through the housing  61 . The housing will generally have a top surface  91 , side surfaces  92  and a front face  93 . Typically, the openings will be in the front face  93  of the housing. The front face  93  of the housing  61  is the side of the housing  61  that faces away from the mounting frame  20 . Typically, the openings  82  in the housing should be positioned in the housing such that the projections  84  will line up with the openings  84 , allowing the projections  84  to contact the locking element  72  as the cover  40  of the dispenser  10  is closed. The size of the opening should be such that the projections  84  easily enter through the opening  82 , but not so large as to allow an adult human finger to fit through the openings  82 . By keeping the openings  82  to smaller than an adult human finger, it is more difficult for a technician to use their finger to override the overfill prevention device  60 . Generally, at least one dimension of the opening  82 , such as the diameter or width will be less than 7 mm, more generally less than 5 mm. In addition to the opening  82 , the housing  61  may further have secondary openings  83  therein to confuse a technician that is trying to override the overfill prevention device. The secondary openings  83  are generally positioned such that the locking element  72  cannot be contacted with a probe. 
         [0044]    The locking element  72  may further optionally have one or more legs  74 , extending from the second end  79  of the locking element  74 . The legs  74  may serve to extend the locking element  74  into the opening  82  so that the projections will easily contact the locking element  72  as the cover  40  is closed. The legs  74  further provide additional weight to the locking element, allowing the locking element to be positioned in the filling position. 
         [0045]    The bracket  62  will generally have an L shape, a triangular shape or a arc shape. When an L-shape, as is shown in  FIGS. 3 and 4 , the bracket can have additional features such as supports  70 . The supports  70  help provide structural rigidity to the bracket  62 . No matter what the shape of the bracket  62 , the bracket  62  may be provided with one or more slots  63  which are positioned on the bracket  62  at a location which corresponds with the openings  82  in the housing  61 . The slots  63  facilitate the bracket  62  moving from the filling position, shown in  FIG. 6 , to the dispensing position, shown in  FIG. 8 . The slots  63  allow the bracket  62  to move from the filling position to the dispensing position around the projections  84  on the inside surface  44  of the cover  40  as the cover is being closed. It is noted that the slots  63  are optional, but depending on the location of the openings  82  in the housing  61 , the slots could be required. That is, the lower on the front face  93  the opening  82 , the more likely the slots  63  will be needed on the bracket  62 . 
         [0046]    In the present invention, there are typically at least two projections  84  located on the inner surface  44  of the cover  20 , at least two complementary openings in the housing  61  and there are at least two legs  74  of the locking element. Typically, there will be two of each. Having a single projection, opening or leg could cause the overfill prevention device to not properly work if the projection was damaged. In addition, having two or more of each of these elements allows the force being applied by the projections to be more evenly distributed to the locking element. 
         [0047]    In the overfill prevention device, the locking element  72  and the bracket  62  are positioned in the filling position, shown in  FIG. 6 , by the force of gravity. That is, the natural state for both the bracket  62  and the locking element are in the positions shown in  FIG. 6 , even when the dispenser is empty (i.e., does not contain a stack of folded sheet) or the dispenser is less than full (i.e., contains less than a full stack of folded sheets. It is noted that both the locking element  72  and the bracket  62  could be biased into the position shown in  FIG. 6 , by using mechanical means such as a spring, without departing from the scope of the present invention. However, given that the force of gravity is sufficient, it is preferred that no biasing mean is used. 
         [0048]    To gain a better understanding of the operation of the overfill prevention device  60  of the present invention, attention is directed to  FIGS. 6-8 .  FIG. 6  shows the overfill prevention device  60  in the filling position. In this position, gravity or another biasing force causes both the bracket  62  and the locking element  72  in the position shown in  FIG. 6 . In this position, the locking element  72  engages the upper portion  68  of the bracket  68 . This retains the bracket in the position shown in  FIG. 6 , such that the lower portion  67  of the bracket  62  limits the number of folded sheets that can be in the stack  12 . Generally, the technician will compress the stack  12  so that the maximum number of folded sheets can be loaded into the dispenser  10 . This will result in an upward force  100  being placed on the bracket  62  due to the compression of the folded sheets. This upward force  100  will cause the upper portion  68  of the bracket  62  to apply an upward force onto the locking element  72 . Since the locking element  72  is essentially perpendicular to the upper portion  68 , the locking element  72  is unable to rotate out of the way of the bracket  62 . Once no additional folded sheets can be added to the stack  12 , the technician will generally close the cover  40 . 
         [0049]    As the technician closes the cover  40 , the projections  84  on the inner surface  44  of the cover, will move through the opening  82  in the housing  61 . In this regard attention is directed to  FIG. 7 . As the projections  84  move through the opening  82 , the projection  84  will contact the locking element  72 . As the cover  40  is continued to be closed by the technician, the locking element  72  is caused to move in an arc  75  about the pivot point  76 . As the locking element  72  clears the upper portion  68  of the bracket  62 , the bracket  62  becomes free from the locking element  72  and the force  100  exerted by the compressed stack of folded sheets  12  cause the bracket  62  to move in the arc  65  about the pivot point  69 . The bracket  62  will move in the arc  65  to a position similar to that shown in  FIG. 8 . It is noted that the actual distance the bracket  62  will move is dependent on the force exerted by the stack of folded sheets  12 . It is noted that the stack of folded sheets  12 ′ shown in  FIG. 8  is in a less compressed state that the stack shown in  FIG. 6  or  7 . Applicants also noted that it is not necessary for the bracket  62  to move. If the stack of folded sheets is not compressed, or is only slightly compressed before the cover  40  is closed, it is possible that the bracket could remain in the position shown in  FIG. 6 . 
         [0050]    If the bracket  62  does move to the position shown in  FIG. 8 , as the individual sheets are removed from the dispenser and the stack becomes shorter, the bracket  62  will return to the position shown in  FIG. 6 . It is noted that the locking element  72  will remain in a position shown in  FIG. 8  or will return to a position such that the locking element  72  will contact the projection  84 , until the cover  40  is again opened. Once the cover is open, the locking element will return to the position shown in  FIG. 6 , provided that a sufficient number of folded sheets are removed from the dispenser. If only a few sheets have been removed, the locking element would remain in the position shown in  FIG. 8 . 
         [0051]    Typically, the components of the folded sheet dispenser of the present invention as described above may be formed of any suitable material, including metal, plastic, and so forth. The construction of such dispensers is well known to those skilled in the art and need not be described in great detail herein. 
         [0052]    The advantages of the present invention is that the overfill prevention device is a simple, low cost and effective way to prevent the technician servicing the folded sheet dispenser from overfilling the dispenser. Further, the overfill prevention device of the present invention is functional without the need for biasing elements, that can cause problems and add complexity for prior art overfill prevention devices. 
         [0053]    Although the present invention has been described with reference to various embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. As such, it is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is the appended claims, including all equivalents thereof, which are intended to define the scope of the invention.