Abstract:
A vacuum apparatus holds flat printed product in a feeder tray of a document feeding apparatus. The apparatus is particularly useful for feeding sheet material such as newspapers one at a time from the bottom of a stack. The apparatus uses existing vacuum connections in the document feeder and is easily mounted to existing feeder trays as part of a retrofit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority on U.S. Provisional Application Ser. No. 61/152,485 filed Feb. 13, 2009, which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to an apparatus for holding down flat products such as newspaper inserts, sheets, signatures and the like in a feeder tray. More particularly, the invention relates to a vacuum hold down apparatus for a feeder tray. 
         [0004]    2. Description of the Related Art 
         [0005]    In the graphic arts and newspaper industries, sheet feeding apparatus for feeding sheet material one at a time from the bottom of a stack are often employed to automatically feed flat printed or other products such as newspapers. The bottom conveyance type of document feeding apparatus is conventionally used as it is excellent for paper separating efficiency. 
         [0006]    The bottom conveyance type of sheet feeding apparatus typically has two basic sections that operate together in coordinated fashion. First, a feeder tray provides a horizontal support on which a vertical stack of sheet material is loaded. Second, a feeding system located adjacent to the feeder tray feeds the flat printed or other products such as newspapers into other areas of the machine. 
         [0007]    Devices for feeding sheet material from the bottom of a stack are typically of two types, friction feeders or gripper feeders. Friction feeders, under normal conditions, are very reliable in feeding sheets individually from the bottom of a stack. However, they are particularly susceptible to misfeeds and/or multi-feeds when subject to the harsh environment of feeding newspaper. Gripper feeders are more reliable for feeding sheets in harsh environmental conditions, but require precise complex control to assure pickup of single sheets (i.e., for prevention of misfeeds or multi-feeds). 
         [0008]    Furthermore, vacuum suckers in a gripper feeder have a tendency to adhere to only the outer half of the jacket on voluminous newspapers having loose collections of other sections. In some city newspapers, the outermost jacket is simply used to receive a loose, side-by-side collection of other sections within itself and lacks a cooperating interleaving between the outer jacket and those sections there within. The tremendous weight and friction of those newspapers above the bottom one in the stack may cause the outer jacket to be feed while the contents of the jacket stay behind, thereby failing to feed the entire newspaper and resulting in frustrating, time consuming jam-ups of the equipment. 
         [0009]    Conversely, if thin, single sheet articles such as inserts are attempted to be fed at the other extreme, the vacuum can bleed through to the next article above so that proper separation does not occur and more than one article at a time is fed. In addition, other problems such as static charge attraction between sheets, tacky or partially dried ink, and misalignment of the vertical stack of sheet material can also result in multi-feeds. 
         [0010]    Thus, a need exists for an apparatus for holding down flat products such as newspaper inserts, sheets, signatures and the like in a feeder tray to insure proper paper separation. For best results, the sheet hold down process should be able to be performed automatically or semi-automatically. 
       SUMMARY OF THE INVENTION 
       [0011]    The invention provides an apparatus for holding flat paper products in a feeder tray of a bottom conveyance type of document feeder to insure that sheet material feeds one at a time from the bottom of the stack. The invention also provides a vacuum hold down apparatus for a feeder tray that utilizes existing vacuum connections to the document feeder. The invention also provides a vacuum hold down apparatus for a feeder tray that is economical to build and easily mounted on to existing feeder trays as part of a machine upgrade or retrofit. 
         [0012]    The invention utilizes a vacuum cross bar that is configured to mount on to preexisting feeder trays. Broadly speaking, the vacuum hold down apparatus comprises a base having a flat bottom surface for mounting the base to the feeder tray. The base has a top surface for receiving a flat product which is connected at a forward edge to the bottom surface. A third surface connects the bottom surface to the top surface at a rearward edge. A channel is proximately located on the top surface of the base in contact with the flat product. A hollow bore is proximately located in an interior portion of the base and is connected to the channel through a plurality of vacuum ports proximately located in the channel. 
         [0013]    In one embodiment of the invention, the top surface has a curvilinear recess proximately located forward of the channel. The purpose of this recess is to provide a cavity for the folded end of the bottom newspaper to lie while the second newspaper in the stack rests against the vacuum channel and is restrained by the vacuum. The top surface has a forward facing angle to provide a slight gravity feed to the newspaper. In this embodiment, the third surface is an arcuate surface to provide additional clearance for the folded end of the stack of newspapers. 
         [0014]    A longitudinal channel is centered on the angle portion of the top surface to provide a vacuum plenum. The purpose of this plenum is to hold the second flat paper product in the stack while the bottom product is fed. A series of holes intersect the channel and run the entire length. At the other end, the holes intersect a hollow bore that passes through the center of the base. The thru bore design is preferred from an ease of manufacturing perspective. One end of the bore is supplied with a standard threaded or press-fit fitting for insertions into the bore. The other end of the fitting is a standard threaded or quick-disconnect hose type fitting which is commonly available in the art. Standard flexible hosing is used to connect the vacuum hold down apparatus to the existing vacuum source of the machine. A throttling or metering valve maybe installed in the vacuum line to control the level of vacuum supplied. Automatic regulation of the vacuum is also considered within the scope of the invention. The other end of the bore has a standard threaded or press-fitted plug to seal the end of the cavity. 
         [0015]    A counter bored hole is provided through the third surface which allows for the insertion of a bolt or machine screw to attach the vacuum hold down apparatus to the feeder tray. The counter bore allows the bolt or screw head to be recessed away from the flat paper product to preclude interference between the bolt and the flat product. A tee nut is provided to align the apparatus in the existing slots which are commonly part of a feeder tray. Bolt and tee nut size is variable and can easily be matched to any slots size. 
         [0016]    In another embodiment, the invention comprises a wedged-shaped structure having a bottom surface for mounting the base to a feeder tray and an angled top surface for receiving a flat product. The top surface has a forward facing angle to provide a slight gravity feed to the newspaper and is connected at a forward edge to the bottom surface. A third generally vertical surface connects the bottom surface to the top surface at a rearward edge. A longitudinal channel proximately located on the top surface of the base is biased towards the rearward end of the top surface to provide vacuum to hold the trailing edge of the flat paper product during feeding. A hollow bore is proximately located in an interior portion of the base and is connected to the channel through a plurality of holes forming a vacuum port. A series of counter bored holes are provided to fasten the base to the feeder tray. The series of holes provides flexibility in mounting the base to the feeder tray and insures that the wedge is compatible with the multiple feeder tray slot arrangements commercially available. A means for attaching the base to a vacuum source is also provided. 
         [0017]    The vacuum wedge base has a smaller longitudinally width than the curvilinear base and is preferably used in pairs proximately spaced at a distance equal to the width of a newspaper. A center wedge support is mounted in between the two small wedge bases to support the center of the newspaper pile. The vacuum connection to the two bases is a parallel source connection using standard hose as known in the art. 
         [0018]    Those skilled in the art will further appreciate the above-mentioned advantages of the vacuum hold down apparatus, together with other important aspects thereof, upon reading the detailed description which follows in conjunction with the drawing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    These and other aspects of the present invention may be more fully understood by reference to one or more of the following drawings, in which: 
           [0020]      FIG. 1  is a perspective view showing the external appearance of one embodiment of the invention installed on a feeder tray; 
           [0021]      FIG. 2  is a perspective, simplified view of the invention of  FIG. 1  showing certain internal structures; 
           [0022]      FIG. 3  is a perspective view of the invention of  FIG. 1  showing the interface with a flat product; 
           [0023]      FIG. 4  is a perspective view showing the external appearance of an alternate embodiment of the invention; and 
           [0024]      FIG. 5  is a perspective view showing the external appearance of an alternate embodiment of the invention installed on a feeder tray. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    A preferred embodiment of the invention will be described, but the invention is not limited to this embodiment. 
         [0026]    The overall external appearance of one embodiment of a vacuum hold down apparatus  10  installed on feeder tray  12  is shown in  FIG. 1 . Vacuum hold down apparatus  10  comprises base  14  having flat bottom surface  16 ,  FIG. 2 , for mounting base  14  to feeder tray  12 . Base  14  has top surface  18  for receiving flat product  20 ,  FIG. 3 . Top surface  18  is connected to bottom surface  16  at forward edge  22 ,  FIG. 2 . Third surface  24  connects bottom surface  16  to top surface  18  at rearward edge  26 . Channel  28 ,  FIGS. 1-3 , is proximately located on top surface  18  of base  14  in contact with flat product  20 ,  FIG. 3 . Hollow bore  30  is proximately located in an interior portion of base  14 . A plurality of vacuum ports  32 ,  FIGS. 1-3 , connect channel  28  to hollow bore  30 . 
         [0027]    In this embodiment of the apparatus  10 , top surface  18  has curvilinear recess  34  proximately located forward of channel  28  as shown in  FIGS. 1-3 . The purpose of recess  34  is to provide a cavity for the folded end of the bottom newspaper  20  to lie while the second newspaper  20  in the stack (not shown) rest against vacuum channel  28  and is restrained by the vacuum. Top surface  18  has forward facing angle  36 ,  FIG. 2 , to provide a slight gravity feed to newspaper  20 . In this embodiment, third surface  24  is an arcuate surface to provide additional clearance for folded end of the stack (not shown) of newspapers  20 . 
         [0028]    As shown in  FIG. 1 , one end of base  14  is supplied with standard threaded or press-fit fitting  40  for insertions into bore  30 ,  FIG. 2 . The other end of fitting  40  is a standard threaded or quick-disconnect hose type fitting which is commonly available in the art. Standard flexible hosing  42  is used to connect vacuum hold down base  14  to existing vacuum source  44 . A throttling or metering valve (not shown) maybe installed in the vacuum line to control the level of vacuum supplied. The other end of base  14  has standard threaded or press-fitted plug  46  to seal the end of bore  30 ,  FIG. 2 . Counter bored hole  50  is provided through third surface  24  for bolt or machine screw  52 . Bolt or machine screw  52  with washer  54  and tee nut  56  are used to attach the vacuum hold down apparatus  10  to feeder tray  12 . 
         [0029]    Base  14  is preferentially made of aluminum or stainless steel and fabricated using conventional machining processes, although molded composite or resin processes may be used to form base  14 . 
         [0030]    In another embodiment as shown in  FIG. 4 , the apparatus  10  comprises wedged-shaped structure  60  having bottom surface  62  for mounting structure  60  to feeder tray  12 . Angled top surface  64  for receiving flat product (not shown) has forward facing angle  66  to provide a slight gravity feed to newspaper (not shown) and is connected at forward edge  68  to bottom surface  62 . Third generally vertical surface  70  connects bottom surface  62  to top surface  64  at rearward edge  72 . Longitudinal channel  74  proximately located on top surface  64  of structure  60  is biased towards rearward end  72  of top surface  64  to provide vacuum to hold the trailing edge of the flat paper product (not shown) during feeding. Hollow bore  76  is proximately located in an interior portion of structure  60  and is connected to channel  74  through holes  78  forming a vacuum port. Series of counter bored slots  80  are provided to fasten structure  60  to feeder tray  12  using bolt or machine screw  84 ,  FIG. 5 . 
         [0031]    As shown in  FIG. 5 , vacuum wedge base is preferably used in pairs  90 ,  92 . Left wedge-shaped base  90  has inner vertical edge  90   a  and outer vertical edge  90   b.  Right wedge-shaped base  92  has inner vertical edge  92   a  and outer vertical edge  92   b.  The spacing of left base  90  with respect to right base  92  on feeder tray  12  is such that outer vertical edge  90   b  of left base  90  is spaced proximately equal to the width of a newspaper (not shown) from outer vertical edge  92   b  of right base  92 . Center wedge support  94  is mounted in between wedge bases  90 ,  92 , proximately spaced equidistance from inner edge  90   a  of left base  90  and inner edge  92   a  of right base  92  to support the center of the newspaper pile (not shown). Bolt or machine screw  96  attaches center support  94  to feeder tray  12 . Vacuum connection  98  is a parallel source connection using standard hose as known in the art to supply vacuum to bases  90 ,  92 . 
         [0032]    Although only a few embodiments of the present invention have been described, the invention is, nonetheless, to be broadly construed, and is not to be limited to these embodiments, and the scope is defined by the claims appended hereto. Those skilled in the art will recognize the above-described features and advantages of the invention and that various substitutions and modifications may be made without departing from the scope and spirit of the appended claims. 
       REFERENCE CHARACTERS 
       [0033]      10  Vacuum Hold Down Apparatus 
         [0034]      12  Feeder Tray 
         [0035]      14  Base 
         [0036]      16  Bottom Surface 
         [0037]      18  Top Surface 
         [0038]      20  Flat product 
         [0039]      22  Forward Edge 
         [0040]      24  Third Surface 
         [0041]      26  Rearward Edge 
         [0042]      28  Channel 
         [0043]      30  Hollow Bore 
         [0044]      32  Holes 
         [0045]      34  Curvilinear Recess 
         [0046]      36  Forward Facing Angle 
         [0047]      40  Fitting 
         [0048]      42  Hose 
         [0049]      44  Vacuum Source 
         [0050]      46  Plug 
         [0051]      50  Hole 
         [0052]      52  Bolt or Machine Screw 
         [0053]      54  Washer 
         [0054]      55  Tee Nut 
         [0055]      60  Wedge Shaped Base 
         [0056]      62  Bottom Surface 
         [0057]      64  Angled Top Surface 
         [0058]      66  Forward Facing Angle 
         [0059]      68  Forward Edge 
         [0060]      70  Third Vertical Surface 
         [0061]      72  Rearward Edge 
         [0062]      74  Channel 
         [0063]      76  Hollow Bore 
         [0064]      78  Holes 
         [0065]      80  Slots 
         [0066]      84  Bolt or Machine Screw 
         [0067]      90  Left Base 
         [0068]      90   a  Inner Vertical Edge 
         [0069]      90   b  Outer Vertical Edge 
         [0070]      92  Right Base 
         [0071]      92   a  Inner Vertical Edge 
         [0072]      92   b  Outer Vertical Edge 
         [0073]      94  Center Support 
         [0074]      96  Bolt or Machine Screw 
         [0075]      98  Vacuum Supply Hose