Abstract:
An apparatus feeds paper inserts or other flat products from one area to another. The apparatus is particularly useful for use with newspaper insert machines. A first rotating disk presses against a first roller, and a second rotating disk presses against a second roller. Each roller is arranged to rotate about an axis of rotation that is movable with respect its opposing disk. Moving each roller toward its opposing disk permits thin products to be fed through the apparatus, and moving each roller away from its associated disk permits thick products to be fed through the apparatus.

Description:
STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT 
       [0001]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to an apparatus for feeding flat products such as newspaper inserts, sheets, signatures and the like into pockets or other areas of a machine. More particularly, the invention relates to an improved feeder capable of feeding products of different thicknesses. 
         [0004]    2. Description of the Related Art 
         [0005]    In the graphic arts and newspaper industries, insert machines are often employed to automatically insert flat printed or other products into newspapers. Examples of some commercially available insert machines are described in U.S. Pat. Nos. 4,723,770; 5,823,320; and 6,907,316. 
         [0006]    An insert machine typically has three basic sections that operate together in coordinated fashion. First, a straight-line pocket conveyor is arranged to carry a series of V-shaped or U-shaped pockets along a closed path. The pockets are typically oriented vertically with the open side of the “V” facing up, and they are carried horizontally by the conveyor. An example of one type of pocket is shown as element 300 in FIG. 1 of the above-mentioned &#39;770 patent. 
         [0007]    Mounted above the conveyor are one or more automatic feeder devices. See, for example, feeders 200 and 500 shown in FIG. 1 of the &#39;770 patent. Other types of feeders are shown in U.S. Pat. No. 5,823,320 (FIG. 1, element 2), in U.S. Pat. No. 6,907,316 (element 16 of FIGS. 1-3), and in pending U.S. patent application Ser. No. 11/250,721, owned by the assignee of the present invention. Such feeders typically employ one or more rotating disks, rollers or drums within the feeder, together with suction cups and other devices, to pull sheets from the bottom of the stack and feed them down into the pockets. 
         [0008]    In a typical operation, one feeder feeds a “jacket” of a newspaper vertically down into the pockets, one jacket per pocket. Next, as the pockets move downstream, they pass under other feeders that feed inserts down into each jacket. Finally, when inserting is complete, a gripper conveyor (such as structure 700 in FIG. 1 of the &#39;770 patent) picks up the completed newspapers from the pockets and carries the products away for further handling. 
         [0009]    Several design features need to be employed to achieve very high feeding speeds, consistent with accurate and efficient paper handling. First, the product must be transferred as quickly as possible from a stationary stack to a moving pocket. When the product is being transferred vertically, the force of gravity is used to assist in product transfer. But gravity is not enough. Just letting the product fall into the pocket does not enable transfer speeds at the desired high rate. An additional mechanical pushing or pulling force is also needed. An accelerating device is sometimes used to grab and “shoot” the product down into the pocket or other parts of the machine as fast as possible. 
         [0010]    Next, the product, which is usually a thin, flexible paper insert, must be transferred while keeping the product as straight as possible to maximize transfer speeds while minimizing crumpling or warping in the pocket. Then, once the product has been transferred to the pocket or other area, it must not be allowed to “crash” into, crumple or jam inside the pocket. 
         [0011]    Prior art feeders having a design similar to the design of the feeders described in the above-mentioned patents and pending application are quite suitable for many applications. For example, many newspaper inserts are extremely thin, having a thickness of perhaps one sheet of newsprint-style paper. These sheets can be effectively and rapidly fed from a stack of sheets into a series of pockets using an arrangement of internal rollers or disks pressing against each other to form one or more “pinch” points that grab the inserts and pass them to the pockets. Since the inserts in a particular feeder during a particular machine “run” are normally of uniform thickness, the feeding rollers can be mounted on fixed axes of rotation. This arrangement simplifies the design, and is often necessary. Because of the thinness of the inserts and the high feeding speeds required, the feeding rollers must press against each other firmly and consistently. 
         [0012]    For some applications, however, it is desirable to have the capability to feed relatively thick inserts or other products, such as magazines, computer disks or even paperback books. While some prior art feeders could be manually adjusted to handle products of varying thicknesses, this adjustment process was typically quite time-consuming, particularly if a large number of feeders were being employed. Also, for safety and other reasons, the entire insert machine frequently needed to be shut down while the manual adjustments were being made, which necessarily slowed down the entire inserting process. Thus, a need exists for a feeder that can be quickly adjusted to handle products of different thicknesses. For best results, the adjustment process should be able to be performed automatically or semi-automatically. 
       SUMMARY OF THE INVENTION 
       [0013]    The present invention satisfies the above-mentioned needs. An improved feeder device has been designed that can be quickly adjusted to accommodate widely varying thicknesses of newspaper inserts and other products. Certain features of the invention relate to improvements in the feeder described in the above-mentioned pending application Ser. No. 11/250,721, while other features of the invention are completely new. Feeding speeds of tens of thousands of products, of different thicknesses, per hour can be achieved. 
         [0014]    In one embodiment of the invention, a row of pivoting sucker cups pulls down the leading edge of the lowermost product in the feeder stack. Then another device momentarily holds down the leading edge while the sucker cups pivot out of the way. Next, a segmented pusher disk pushes the leading edge down to a nip or pinch point formed between two opposing rollers. Next, the product is passed to another nip formed between another set of opposing rollers operating at a higher speed. The high speed rollers accelerate the product down into a pocket passing below. All rollers are spring-loaded and are mounted on axes of rotation that are not fixed. The rollers can pivot toward and away from each other, to allow thicker products to be fed through the machine. The springs pushing on the rollers may be quickly adjusted automatically or semi-automatically to accommodate products of different thicknesses. 
         [0015]    More specifically, in one embodiment, the invention comprises a feeder comprising a housing having a tray for receiving flat products in a stationary stack; a first roller mounted within the housing and biased against a first disk; and a second roller mounted within the housing and biased against a second disk; whereby each roller is arranged to rotate about an axis of rotation that is movable either toward or away from the first and second disks respectively, to allow products of different thicknesses to be fed from the stack, between the first roller and first disk, and between the second roller and the second disk. 
         [0016]    In another embodiment, the invention comprises an apparatus for feeding flat paper products, comprising a housing having a tray for receiving flat products in a stationary stack; a first rotatable backup roller mounted within the housing and biased against a segmented rotating pusher disk, the first backup roller being arranged to rotate about an axis of rotation that is pivotable either toward or away from the pusher disk; and a second rotatable backup roller mounted within the housing and biased against a second disk, the second backup roller being arranged to rotate about an axis of rotation that is pivotable either toward or away from the second disk; whereby the distance between the first backup roller and the pusher disk, and the distance between the second backup roller and the second disk, may be adjusted to permit products of different thicknesses to be fed from the bottom of the stack and between the first backup roller and the pusher disk, and between the second backup roller and the second disk, respectively. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    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: 
           [0018]      FIG. 1  is a perspective view showing the external appearance of one embodiment of the invention; 
           [0019]      FIG. 2  is a side cutaway view of the invention; 
           [0020]      FIG. 3  is a perspective, simplified, cutaway view of the invention showing certain internal structures; 
           [0021]      FIG. 4  is a top cutaway view of the invention; 
           [0022]      FIG. 5  is a side cutaway close-up view of the main spring adjustment assembly  402  of  FIGS. 3 and 4 ; 
           [0023]      FIG. 6  is a perspective, simplified, external view of the invention showing pulsed air separator orifices; and 
           [0024]      FIG. 7  is a stripper bar assembly that may be used with the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    The following is a description of one embodiment of the present invention that is particularly useful for feeding flat paper, plastic or other products, such as inserts, sheets, cards, signatures, magazines, books, disks, mail, film packages, etch, from a stationary location to a moving location. Varying thicknesses of products can be accommodated. In this embodiment, a sheet or other product is grabbed from the bottom of a stationary stack, pulled through the machine by a series of disks, rollers and other devices, and is then subsequently delivered at high speed to a moving, vertically-oriented pocket open at the top and being carried by a linear conveyor moving horizontally beneath the product feeder. The invention is not, however, limited to such use and is usable in any environment where feeding of a flat product is needed to transfer the product from one location in a machine to another efficiently and at very high speed. 
         [0026]    The overall external appearance of one embodiment of the invention is shown in  FIG. 1 . Typical newspaper inserts  10  are shown stacked in tray  12  on top of the machine  1 , ready to be fed down into pockets (not shown) moving underneath feeder  1 .  FIG. 6  shows the external appearance of the housing or frame of the invention. The major internal moving parts are shown in  FIGS. 2-5 . These figures are discussed in more detail below. 
         [0027]    Looking next at  FIG. 2 , the invention comprises feeder  1  driven by motor  270  for feeding flat products such as paper inserts  10  one at a time from the bottom of a stack resting on tray  12  down into open pockets (not shown). Preferably, feeder  1  is mounted above a horizontal, linear, moving conveyor (not shown) carrying the pockets (not shown) oriented vertically. 
         [0028]    The operation of a preferred embodiment of the invention will now be described in detail. First, as best seen in  FIGS. 2 and 4 , reciprocating sucker bar  221  pivots upward toward lowermost sheet  10  or other product  10  resting on tray  12 . Suckers  220  mounted on sucker bar  221  engage leading edge  10   a  of lowermost sheet  10 , and vacuum is applied. In  FIG. 2 , “leading edge”  10   a  is the left edge of sheet  10 . After leading edge  10   a  has been grabbed by suckers  220 , sucker bar  221  begins to pivot downward. This bends leading edge  10   a  downward and forms a triangular-shaped gap (not shown) between leading edge  10   a  of lowermost sheet  10  and leading edge  10   a  of next lowermost sheet  10 . Next, a pulse of air is blown into the gap (not shown) for a fraction of a second to create an air bearing that helps to maintain separation between two sheets  10 . As shown in  FIG. 6 , the air pulses are blown from one or more orifices  600  mounted slightly below and to the left of tray  12 . Air is pulsed in timed relationship with the movement of suckers  220 . The air pulses also help to lift the stack to take weight off of the piece of product  10  being fed, preventing the stack from rolling out. 
         [0029]    Next, in a feature of the invention, hold-down finger  450  ( FIG. 2 ) pivots to the right and downward until finger tip  452  ( FIGS. 2 and 4 ) of each finger presses down against leading edge  10   a  of lowermost sheet  10  for a fraction of a second. Hold-down finger tip  452  is best seen in  FIG. 4 . Hold-down finger  450  is driven in an oscillatory motion by eccentric  464  ( FIG. 2 ), which is a type of crank, attached to connecting link  462 . Finger  450  pivots around pivot point  460 . 
         [0030]    In another feature of the invention, one or more rotating, segmented pusher disks  204  are mounted next to hold-down finger  450 . Pusher disks  204  are driven by motor  270 . As shown in  FIG. 2 , pusher disks  204 , which have two or more drive segments  205  with curved outer surfaces and relatively sharp ends, are constantly rotating clockwise. Drive segments  205  may be coated with a high-friction material. 
         [0031]    Leading edge  10   a  of lowermost sheet  10  is being momentarily held down, vacuum to suckers  220  is turned off. Next, the sharp end of one of pusher disk drive segments  205  enters the triangular gap (not shown) between two sheets  10  and bends lowermost sheet  10  down further. Next, sucker bar  221  pivots to the left to move suckers  220  out of the way and in preparation for engaging next sheet  10  in the stack. Next, curved outer surface  206  of one of pusher disk drive segments  205  engages low-speed backup roller  210 . The outer surface of roller  210  is preferably coated with rubber or other high-friction material. 
         [0032]    The engagement of disk  204  with roller  210  creates a low-speed, frictional nip or pinch point. As soon as leading edge  10   a  of sheet  10  has been bent down to this pinch point, disk  204  and roller  210  grab sheet  10  and start to pull it linearly to the left off of tray  12  and down into machine  1 . Roller  210  may be set to one, two, three or more pre-set gage positions relative to disk  204 . 
         [0033]    Mounted next to pusher disks  204  are one or more high-speed disks  250 . As shown in  FIG. 2 , each disk  250  is constantly rotating counterclockwise. Raised portion  252  of the outer periphery of disk  250  is coated with a high-friction material such a rubber. Portion  254  is stepped inward from portion  252  and is coated with a low-friction material, or is simply left uncoated. As disk  250  rotates, raised portion  252  of disk  250  periodically engages the outer periphery of high-speed backup roller  260  mounted adjacent to pusher disk  204 . In  FIG. 2 , backup roller  260  is constantly rotating clockwise. The outer periphery of roller  260  is coated with a high-friction material. 
         [0034]    Disk  250  and roller  260  pressing together form a high-speed, frictional nip or pinch point. As sheet  10  advances down through machine  1 , leading edge  10   a  of sheet  10  is grabbed in the high-speed pinch point, and sheet  10  is immediately accelerated to a faster linear speed down through machine  1 . At approximately the same time sheet  10  is being accelerated, drive segment  205  of pusher disk  204  has rotated further clockwise and no longer engages low-speed backup roller  210 . In other words, the low-speed pinch point has been released. This prevents sheet  10  from being torn apart as sheet  10  moves from the low-speed pinch point to the high-speed pinch point. Also, at approximately the same time, a clutch (not shown) within low-speed backup roller  210  disengages to improve sheet feeding. 
         [0035]    Shortly thereafter, as sheet  10  approaches the bottom of feeder  1 , it passes over adjustable bowing rod  470  ( FIG. 2 ). The purpose of rod  470  is to form a temporary bow in sheet  10 , and to slow sheet  10  down slightly with friction. This stiffens sheet  10  so that, as sheet  10  exits feeder  1  and enters a pocket (not shown) beneath feeder  1 , sheet  10  is less likely to crumple as it hits the bottom of the pocket (not shown) at high speed. 
         [0036]    A significant feature of the invention is that products of widely varying thicknesses can easily be handled. One way this accomplished is that some of rollers  210 ,  260  are mounted on pivoting, as opposed to fixed, axes of rotation. For example, as shown in  FIG. 2  and more clearly in  FIG. 3 , one or more low-speed backup rollers  210  are mounted on roller support shaft  211  ( FIG. 3 ) that is arranged to pivot back and forth around pivot point  410  ( FIG. 2 ). This allows roller  210  to pivot to the right (away from) pusher disk  204  if a gap (not shown) is needed to allow thick products  10  to pass between roller  210  and disk  204 . Similarly, high-speed backup roller  260  is mounted on separate arm  262  that allows roller  260  to pivot either toward or away from high-speed disk  250 . Roller support shaft  211  ( FIG. 3 ), on which low-speed backup rollers  210  are mounted, is also able to pivot around a vertical axis (see  FIG. 4 ). This permits rollers  210  to pivot back and forth horizontally (see  FIG. 4 ), to accommodate inserts  10  of uneven or non-uniform thicknesses. 
         [0037]    In addition to pivoting axes of rotation, backup roller  210 ,  260  are all spring-loaded, This is best seen in  FIG. 3 . More particularly, main spring  400  is attached to pivoting arm  212  of backup roller  210 , and secondary spring  405  is attached to pivoting arm  262  of backup roller  260 . Springs  400 ,  405  are in compression. Spring  400  urges roller  210  against pusher disk  204  (not shown in  FIG. 3 ), and spring  405  urges roller  260  against high-speed disk  250  (not shown in  FIG. 3 ). Main spring  400  is also shown in  FIGS. 4 and 5 . Springs  400 ,  405  are mounted to surround spring rods  406 ,  440 , such as spring rod  440  shown in  FIG. 5 , to add structural support and to facilitate adjustment. 
         [0038]    Compensating rollers (not shown) may also be included in feeder  1 . 
         [0039]    In yet another feature of the invention, feeder  1  can be quickly and easily reconfigured between machine runs to accommodate products  10  of different thicknesses. To maintain appropriate bias in springs  400 ,  405 , as products  10  of different thicknesses are introduced, there is provided main spring adjustment assembly  402  and secondary spring adjustment assembly  407 . Assemblies  402 ,  407  are best seen in  FIGS. 3-5 . Assembly  402  permits adjustment of spring  400 , and assembly  407  permits adjustment of spring  405 . 
         [0040]    Adjusting spring  400 ,  405  involves moving spring rod  406 , 440  either back or forth, to adjust the compression on rollers  210 , 260 . This adjusts the spring bias at the pinch points. In other words, for example, if thick products  10  are to be fed, performance is improved if the spring bias at the pinch point is reduced. Conversely, if very thin products  10  are to be fed, the spring bias should be increased to maintain adequate friction at the pinch points so that products  10  can be fed reliably and quickly through machine  1 . 
         [0041]    The mechanism for moving spring rod  440  is shown in  FIG. 5 . As can be seen, mainspring  400  is wound around spring rod  440 . Main spring  400  applies a biasing force to low speed backup roller  210  ( FIG. 4 ), which causes roller  210  to press against curved drive segments  206  of pusher disk  204 . Looking again at  FIG. 5 , spring rod  440  passes through opening  408  in a fixed structural member  409 , and rod  440  can move up and down for a short distance. Attached to the lower end of rod  440  is wedge-shaped block  435 , which will be called “wedge Y.” Second wedge  430  (“wedge X”) rests on top of wedge Y  435 , with the slanted surfaces pressing against each other. Wedge X  430 , in turn, is attached to air cylinder rod  510 , which is housed within air cylinder  503 . Air cylinder  503  consists of return spring  503  ( FIG. 3 ), air brake fitting  507 , air cylinder fitting  508 , air cylinder  510 , spring  511 , and seal  513 . Rod  510  is arranged to move back and forth within air cylinder  503  if compressed air is introduced into cylinder  503 . Alternatively, air cylinder rod  510  may be moved back and forth by introducing liquid into cylinder  503 , or by mechanical or electromechanical means. Another spring  511  is also attached to air cylinder  503  (see  FIG. 5 ). 
         [0042]    The arrangement shown in  FIG. 5  permits feeder  1  to be adjusted to accommodate products  10  of different thickness. For example, it can be seen that if wedge X  430  is forced to the left by air in air cylinder  503 , the slanted surface of wedge X  430  will slide over the slanted surface of wedge Y  435 , which will force wedge Y downward, together with attached spring rod  440 . This will reduce the compressive force in main spring  400 . A gap (not shown) between rollers  210 ,  260 , is set that is smaller than the thickness of insert  10  being fed. In this way, thicker products  10 , can pass between low speed backup roller  210  and pusher disk  204  ( FIG. 2 ). Some force on backup roller  210  is still required, so brake structure  520  driven by brake piston  522  ( FIG. 5 ) prevents wedge X  430  from traveling too far over the top of wedge Y  435 . Brake structure  520  consists of brake piston  522 , seal  523  and friction material  524 . If thin products  10  are to be fed through machine  1 , air is again introduced into air cylinder  503 , which will force wedge X  430  to the right, which will in turn force spring rod  440  upward to increase the compressive force in spring  400 . Wedge X  430  remains firmly adjacent to wedge Y  435  by a return spring  504  ( FIG. 3 ), which is under tension. 
         [0043]    Secondary spring adjustment assembly  407  ( FIG. 3 ) is identical to main spring adjustment assembly  402 , except that assembly  407  is arranged to permit the adjustment of high-speed backup roller  260 , to allow products  10  of different thickness to pass between the pinch point formed by roller  260  pressing against high speed disk  250 . 
         [0044]    In a preferred embodiment, adjustment of feeder  1  is performed semi-automatically by an operator at the start of a “run” of insert machine  1 . The operator will note the thickness of products  10  of feeder tray  12 , and then engage air to move spring rod  440  either backward or forward by the proper amount. Alternatively, product thickness may be determined automatically by sensor  475  ( FIG. 2 ) positioned within feeder  1 . Sensor  475  may be connected to electromechanical or pneumatic means (not shown) to automatically adjust rollers  210  and  260 . 
         [0045]    Typically, after a machine run, roller adjustment will be reset so as to create a zero gap (not shown) between rollers  210 ,  260 . As insert  10  is being fed, forcing rollers  210 ,  260  apart, wedge  430 ,  435  automatically moves to the correct position, as long as brake  520  is off (see  FIG. 5 ). 
         [0046]    One aspect of feeder  1 , is that pulsed air “kit” (not shown) is available for separate purchase by a customer as a stand-alone unit and installed into feeder  1 .  FIG. 7  shows stripper bar assembly  800  suitable to use with feeder  1 . Assembly  800  can be mounted underneath feeder tray  12  and adjacent to orifices  600  shown in  FIG. 6 . Stripper bar assembly  800  together with other parts of the kit (not shown) may also be retrofitted onto other types of sheet feeders  1  not covered by the present invention, such as gripper-drum types of feeders  1  used with other insert machines and the like. 
         [0047]    Although only a few embodiments of the present invention have been expressly disclosed, the invention is, nonetheless, to be broadly construed, and is not to be limited except by the character of the claims appended hereto.