Abstract:
A paper shredder includes a housing, cutters positioned in the housing, and a feeder base adapted to support a stack of paper. The feeder base includes a feeder slot. The feeder base further includes a sidewall extending in a direction generally perpendicular to the feeder slot, and an aperture formed in the feeder base at a location spaced from the feeder slot. The aperture provides a pathway between a top surface of the feeder base and a waste area below the feeder base and has a first end closest to the sidewall and defining a first end point closest to the feeder slot, and a second end farthest from the sidewall and defining a second end point closest to the feeder slot. The first end point is closer to the feeder slot than the second end point.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 14/162,957 filed on Jan. 24, 2014, which is a continuation of U.S. patent application Ser. No. 13/927,899 filed on Jun. 26, 2013, now U.S. Pat. No. 8,672,251, which is a continuation of U.S. patent application Ser. No. 13/723,400 filed on Dec. 21, 2012, now U.S. Pat. No. 8,496,197, which is a continuation of U.S. patent application Ser. No. 12/762,000 filed on Apr. 16, 2010, now U.S. Pat. No. 8,336,794, the entire contents of which are hereby incorporated by reference herein. 
     
    
     BACKGROUND 
       [0002]    The present invention generally relates to the field of paper shredders, and specifically to paper shredders that have a mechanism for removing staples and paper clips prior to shredding. 
         [0003]    Paper shredders are commonly used to shred documents in order to preserve the confidentiality of the information on the documents. Shredders come in a variety of sizes, from large industrial shredders capable of shredding stacks of sheets of paper at one time, to personal and office shredders that can shred up to several sheets at one time. 
         [0004]    Personal and office shredders are commonly designed to have paper hand fed into the shredder. These shredders include a slot, typically on the top of the shredder, and sheets of paper are fed into the slot. While these shredders are often designed to accommodate staples and paper clips, it is desirable to remove staples and paper clips prior to shredding in order to prevent damage to or jamming of the shredder. 
         [0005]    Some shredders are designed to accommodate a stack of paper for shredding. These shredders commonly pull sheets of paper from the bottom of a stack for shredding several sheets at a time. When shredding a stack of paper, staples or paper clips can be embedded in the stack, and thus it is impractical to remove all staples and paper clip prior to shredding. While these shredders can often accommodate staples and paper clips, it would be desirable to have a system for removing staples and paper clips from sheets of paper within a stack prior to shredding. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides a paper shredder. The shredder includes a housing, cutters positioned in the housing, and a feeder base adapted to support a stack of paper. The feeder base includes a feeder slot. The feeder base further includes a side edge spaced from and extending generally parallel to the feeder slot, a sidewall extending in a direction generally perpendicular to the feeder slot and the side edge, and an aperture formed in the feeder base at a location spaced from the feeder slot and providing a pathway between a top surface of the feeder base and a waste area below the feeder base. The aperture has a first end point, lying in a first plane perpendicular to the side edge, and closest to the feeder slot, and a second end point, lying in a second plane perpendicular to the side edge, and closest to the feeder slot. The first plane is closer to the sidewall than the second plane, and a distance along the first plane from the side edge to the first end point is larger than a distance along the second plane from the side edge to the second end point. 
         [0007]    The present invention also provides a paper shredder including a housing, cutters positioned in the housing, and a feeder base adapted to support a stack of paper. The feeder base includes a feeder slot. The feeder base further includes a sidewall extending in a direction generally perpendicular to the feeder slot, and an aperture formed in the feeder base at a location spaced from the feeder slot. The aperture provides a pathway between a top surface of the feeder base and a waste area below the feeder base and has a first end closest to the sidewall and defining a first end point closest to the feeder slot, and a second end farthest from the sidewall and defining a second end point closest to the feeder slot. The first end point is closer to the feeder slot than the second end point. 
         [0008]    The present invention also provides a paper shredder including a housing, cutters positioned in the housing, and a feeder base adapted to support a stack of paper. The feeder base includes a feeder slot. The feeder base further includes a first aperture on one side of the feeder slot and a second aperture on a same side of the feeder slot as the first aperture. The first and second apertures provide pathways between a top surface of the feeder base and a waste area below the feeder base. The first and second apertures are spaced apart from one another by a portion of the feeder base between the first and second apertures. Each of the first and second apertures are configured so that a corner of papers in the stack fastened together by a staple folds into a corresponding one of the first and second apertures along a fold line that is oblique to the feeder slot, while the folded papers in the stack remain supported by the portion of the feeder base between the first and second apertures. 
         [0009]    Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  illustrates a paper shredder embodying the present invention. 
           [0011]      FIG. 2  is an exploded view of the shredder of  FIG. 1 . 
           [0012]      FIG. 3  is an exploded view of a feeder assembly of the shredder of  FIG. 1 . 
           [0013]      FIG. 4  is a section view taken along line  4 - 4  of  FIG. 1 . 
           [0014]      FIG. 5  is a perspective view of the shredder of  FIG. 1  with the feeder assembly removed. 
           [0015]      FIG. 6  is a top view of the shredder shown in  FIG. 5 . 
           [0016]      FIG. 7  is a section view taken along line  7 - 7  in  FIG. 6 . 
           [0017]      FIG. 8  is a top view of a shredder that is an alternate embodiment of the present invention. 
           [0018]      FIG. 9  is a bottom perspective view of a feeder assembly of the shredder of  FIG. 10 . 
           [0019]      FIG. 10  is a side view of a pressure plate and feeder base of the second embodiment. 
           [0020]      FIG. 11  is a perspective section view of a rear feeder base taken along line  11 - 11  in  FIG. 10 . 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. 
         [0022]    The illustrated shredder includes a housing  20 , a litter bin  22  positioned in the housing  20 , a top cover  24  mounted on top of the housing  20 , an engine assembly  26  mounted in the top cover  24 , a feeder base  28  mounted on the top cover  24 , and a feeder assembly  30  pivotally mounted to the feeder base  28 . By pivoting the feeder assembly  30  upward, a stack of paper  32  can be placed on the feeder base  28  in preparation for shredding. The feeder assembly  30  is then closed, and the shredding operation is performed by pulling bottom sheets of the stack of paper  32  through the feeder base  28  and into the engine assembly  26 . The paper passes through rotary cutters  34  ( FIG. 8 ) in the engine assembly  26 , which shred the paper and drop it into a waste area where the litter bin  22  is positioned. After shredding is completed, the litter bin  22  can be slid out the front of the housing  20  for disposal. 
         [0023]    The feeder assembly  30  is shown in more detail in  FIGS. 2-4 . The feeder assembly  30  includes a feeder door  40  pivotally mounted to the feeder base  28  and moveable between a lowered position and a raised position. The illustrated feeder door  40  is a one-piece door that substantially covers the entire feeder base and is pivoted about an axis at one end of the feeder door  40 . Two turn springs  42  bias the feeder door  40  toward the raised position. A catch button  44  and latch  46  are mounted on the free end of the feeder door  40 . The catch button  44  is positioned within an opening  48  in the feeder door  40  and is designed to be moveable vertically from a released position to a pressed position. The latch  46  is mounted for horizontal movement relative to the feeder door  40  between a latched position, where it engages a lip  50  ( FIG. 4 ), and an unlatched position. A pair of latch springs  52  bias the latch  46  toward the latched position and, due to a camming interface  54  ( FIG. 4 ) between the latch  46  and the catch button  44 , such bias of the latch  46  also biases the catch button  44  toward the released position. When the catch button  44  is not pressed, it is in the released position and the latch  46  is in the latched position, which will hold the feeder door  40  in its lowered position relative to the top cover  24 . When the catch button  44  is moved toward the pressed position, the latch  46  will be moved toward the unlatched position, which will release engagement between the latch  46  and the lip  50 , and will allow the feeder door  40  to pivot upward to the raised position. 
         [0024]    The feeder assembly  30  further includes a pressure plate  56  mounted adjacent the bottom surface of the feeder door  40 . The pressure plate  56  is a one-piece member that includes a series of posts  60  that are dimensioned to slide within corresponding openings  62  in the feeder door  40  such that the pressure plate  56  can float vertically relative to the feeder door  40 . A series of push springs  64  bias the pressure plate  56  away from the feeder door  40 . Pressure rollers  66  are mounted to the pressure plate  56  and are aligned on opposing sides of a central portion of the pressure plate  56 . The pressure rollers  66  can each rotate about axes Al relative to the pressure plate  56 , but their rotational axes Al are fixed relative to each other. The pressure rollers  66  are designed to apply pressure to a top sheet of a stack of sheets positioned on the feeder base. It should be understood that, in some embodiments, the pressure plate could be made of multiple members. For example, the pressure plate could include a front plate and a rear plate that are completely separate or that are hinged together to allow some degree of independent movement. This would facilitate upward movement of one of the plates (e.g., to accommodate the passage of a staple) while maintaining downward pressure of the other plate (to keep pressure on the stack of paper). 
         [0025]    The illustrated feeder base  28  comprises a front portion  70  and a rear portion  72 , each of which includes an inner end  74  an outer end  76 . Each of the inner ends  74  includes a series of notches  78  that are dimensioned to receive a series of rubber rollers  80  that are part of the engine assembly  26  and are substantially aligned with the pressure rollers  66 . The rubber rollers  80  protrude slightly above a top surface of the feeder base  28  and are rotated by the engine assembly  26  to frictionally draw sheets of paper through a feeder slot  84  and into the rotary cutters  34 . This action is facilitated by the one-piece pressure plate that spans the feeder slot, and by downward pressure provided by the pressure rollers  66  positioned on opposing sides of the feeder slot  84 . As such, when the paper is being drawn into the cutters  34 , the paper moves toward the feeder slot  84 . The rear portion  72  of the feeder base  28  includes hinges  86  that pivotally support the feeder door  40  for pivoting about an axis A 2 . It should be understood that, in some embodiments, the feeder base  28  could be made of a single member (see  FIG. 11 ) instead of separate front and rear portions. 
         [0026]    Each of the front portion  70  and the rear portion  72  of the feeder base  28  includes two apertures  90  that provide an opening between the top surface of the feeder base  28  (which supports a stack of paper  32  in preparation for shredding) and the waste area where the litter bin  22  is positioned below the feeder base  28 . Each aperture  90  is positioned at a corner of the feeder base  28 . That is, each aperture  90  is approximately aligned with a corner of a sheet of paper positioned on the stack. 
         [0027]    A staple plate  92  is secured to the feeder base  28  adjacent each of the apertures  90 . As best shown in  FIGS. 5-6 , each staple plate  92  is positioned at an oblique angle relative to the feeder slot  84  and relative to a side edge  94  of the feeder base  28 . In the illustrated embodiment, the staple plates  92  include an edge  96  positioned above a plane defined by the top surface of the feeder base  28 . The illustrated edge  96  faces the aperture  90  and is at an angle a ( FIG. 6 ) of about 10 degrees relative to the feeder slot  84  and relative to the side edge  94  of the feeder base  28 . As used herein, a “staple plate” is used as a convenient term to describe a plate that can be used to separate a staple S ( FIG. 6 ), paper clip, or other paper-fastening device from a sheet or sheets of paper. The staple plate  92  need not have a straight edge, but instead could have an edge with an angle that varies relative to the feed slot  84 . In this regard, the angle of the edge of the staple plate  92  at any point shall be considered the tangent to the edge at that point. It should also be noted that, while the illustrated embodiment of  FIGS. 1-9  utilizes the edge  96  of the staple plate  92  to define a portion of the aperture  90 , the staple plate  92  could be eliminated, in which case the “edge” would be defined by a portion of the feeder base  28  (see, e.g., the second embodiment of  FIG. 10 ). 
         [0028]    By positioning the edge  96  of the staple plate  92  at an oblique angle a relative to the feeder slot  84 , the bottom sheets  97  of paper will move in a direction that is oblique to the edge  96  of the staple plate  92 . This orientation causes the corner of a stapled stack of paper to fold over in a dog-eared fashion, as shown in  FIG. 7 . When in this position, further movement of the bottom sheets  97  of paper toward the feeder slot (to the right in  FIG. 7 ) causes the bottom sheets  97  to peel away from the staple S. If not for the dog-eared corner, the bottom sheets  97  would need to shear through the staple S, which is more difficult to do consistently and often causes the entire stapled stack of paper to be sucked into the feeder slot and into the cutters, which can cause a jam. After the bottom sheets  97  tear away from the staple S, the next several sheets are pulled into the feeder slot  84 , and the operation continues as described above. When the last several sheets of a staple stack are pulled into the feeder slot  84 , the staple S will be slid toward the feeder slot  84  and into engagement with the edge  96  of the staple plate  92 , where it should be held in place while the remaining sheets are torn away from the staple S. The staple S (and any small pieces of paper attached to the staple S) will then fall through the aperture  90  and into the litter bin  22 . 
         [0029]      FIGS. 8-10  illustrate an alternate embodiment of the present invention. The illustrated shredder  200  has a feeder base  202  that is similar to the feeder base  28  of  FIGS. 1-7 , with the exception of the size and shape of the openings. More specifically, the openings  204  of the second embodiment do not include a staple plate  92 . In addition, the edge of the opening  204  includes a compound angle having an inner first section  206  at an oblique angle β of about ten degrees relative to the feeder slot  208 , and an outer second section  210  at an angle γ of about twenty-eight degrees relative to the feeder slot  208 . This configuration has been found to enhance the ability of sheets of paper to peel-away from a stapled stack. That is, the steeper angle in the outer section  210  has been found to enhance the ability of a stack of sheets to fold over at the corner, thereby facilitating peeling of the lowest sheets of the stack away from the staple, as described above and illustrated in  FIG. 7 . In this embodiment, it has been found that the edge of the opening is sufficient to remove paper clips. In addition, because the cutters are designed to handle staples, it is acceptable if the last few sheets (the top sheets) in a stack of stapled sheets pull the staple into the cutters. 
         [0030]    Referring to  FIGS. 9-10 , the feeder assembly  212  of the second embodiment includes a pressure plate  214  that is substantially shorter than the support surface  216  of the feeder base  202  that supports the stack of paper prior to shredding. More specifically, referring to  FIG. 10 , the pressure plate  214  has a length  218  perpendicular to the feeder slot  208  of about 144 mm, compared to a corresponding length  220  of the support surface  216  of about 284 mm. As a result, the pressure plate  214  has a length that is about 50% of the length of the support surface  216 . In addition, the pressure plate  214  does not overlap with the openings  204  and the inner and outer sections  206 , 210  of the edge of the openings  204  that engage and slide paper clips off of stacks of sheets (best shown in broken lines in  FIG. 8 ). This shorter pressure plate  214  functions to apply most of the pressure in the area of the feeder slot  208 , so that the pressure of the paper on the rubber rollers  80  is enhanced. In addition, this design reduces lifting of the pressure plate when a stack of stapled sheets is folded at the corner (see  FIG. 7 ). Such lifting of the pressure plate will result in a loss of friction on the rubber rollers  80 , which can cause the shredder to slip (i.e., fail to draw sheets into the cutter due to insufficient friction between the rubber rollers  80  and the bottom sheet). As noted above in connection with the first embodiment, the pressure plate  214  can be made of multiple members. For example, the pressure plate  214  could be made from two members that are evenly positioned on opposing sides of the feeder slot and are coupled together by a hinged link. In such an embodiment with multiple pressure plate members, the above-referenced length and size of the pressure plate would be determined by looking at the combined or effective footprint of the pressure plate members. 
         [0031]      FIG. 11  illustrates an alternative embodiment for a feeder base  230  that is a one-piece design. More specifically, the front and rear portions  232 , 234  of the feeder base  230  are connected by an integrally-formed side wall  236  along each side. In addition, the feeder base  230  includes a deflection member in the form of a plate  240  positioned in each opening  242  and tilted relative to horizontal. Each illustrated plate  240  will deflect paper clips that fall off the stacks of sheet being shredded, and will direct those paper clips into smaller ports  244  for falling into the litter bin (not shown in  FIG. 11 ). These plates  240  guide the paper clips around other components of the shredder (e.g., the motor and circuit board). In addition, each of the front and rear portions  232 , 234  of the feeder base  230  includes a recessed portion  246  that will retain some paper clips that slide off and do not fall into the opening  242 . This facilitates the saving and reusing of paper clips. 
         [0032]    Various features of the invention are set forth in the following claims.