Abstract:
This invention discloses an apparatus and method for separating and feeding flat products from a stack to a gripper drum. The invention employs a specially-positioned pivoting and articulating sucker bar, having several degrees of motion, operating in timed relationship with a reciprocating and articulating pusher blade, to reduce the travel distance of vacuum suckers, to reduce the diameter of the gripper drum, and to increase the speed at which products are separated from the stack and transferred to the gripper drum.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     Reference is made to prior copending U.S. provisional patent application No. 60/557,716, filed Mar. 30, 2004, entitled “Product Separator and Feeder,” by the inventors of the present invention. Such application is incorporated herein by reference. 
     
    
     NO GOVERNMENT RIGHTS  
       [0002]     No federally-sponsored research or development was involved with this application.  
       BACKGROUND OF THE INVENTION  
       [0003]     1. Field of the Invention  
         [0004]     This invention relates to an improved apparatus and method for separating flat products such as newspapers and inserts from a stack and feeding them to a drum or other moving machine parts at high speed.  
         [0005]     2. Art Relating to the Invention  
         [0006]     At present, machines for handling flat products, such as newspaper insert machines, often include one or more automatic feeders for feeding the products from a stationary stack to other moving parts of the machine. One item at a time is separated from the stack, either from the top or the bottom, and transferred to a rotating drum or other moving part by a separator device housed within a product feeder. Typically, one or more product feeders are mounted above a conveyor carrying open moving pockets, and the feeders transfer products from the drum into the pockets. An example of an insert machine is shown in U.S. Pat. No. 4,723,770.  
         [0007]     If the flat products are thin or flexible, such as paper sheets or jackets, then several engineering challenges present themselves for proper and efficient machine operation. First, one item at a time must be separated from the stack without separating or damaging the remaining items. Since sheets of paper, for example, tend to stick together when stacked due to friction and air pressure, a means of separating one sheet from the stack sometimes includes a suction device to pull one sheet away while leaving the remaining sheets in place. After separation, the item must be transferred from the stationary stack to other parts of the machine that are moving, such as a rotating drum or a conveyor.  
         [0008]     One example of a prior art separator and feeder apparatus is shown in  FIG. 1 . A hopper having a table  2  holds a stack of flat products  1 . A reciprocating sucker bar  6  is pivotally mounted beneath the lowermost product in the stack. One or more suckers  5  are attached to one end of the sucker bar, and the bar pivots around its other end. Note that, in this prior art device, the pivot point of the sucker bar is situated directly underneath the table and the stack.  
         [0009]     Beneath the hopper and the sucker bar, there is mounted a rotating drum  3 , which carries one or more grippers  7  around its periphery. The grippers open and close at certain, timed positions as the drum rotates (counterclockwise in  FIG. 1 ).  
         [0010]     In operation, as an open gripper rotates up towards the hopper, sucker bar  6  pivots upward and suction is applied to the sucker  5 . The sucker approaches and then makes contact with an edge portion of the lowermost product in the hopper. As used herein, this edge portion, which is the portion closest to the drum, is called the leading edge of the product.  
         [0011]     Next, the sucker bar  6  pivots downward, causing sucker  5  to peel the leading edge of the lowermost product away from the leading edge of the next lowermost product in the stack by suction, and to bend the leading edge of the lowermost product downward. This creates a gap between the lowermost product and the next lowermost product. Meanwhile, the gripper  7  continues to rotate toward the stack. When the gripper moves into a position immediately below the bent-down leading edge of the lowermost product, the gripper closes and grabs the leading edge. Suction is then immediately released from the sucker  5 , and the gripper then pulls the product down and around a portion of the periphery of the drum  3 . Subsequently, the gripper opens and releases the product into a moving pocket  4 , which carries the product away for further processing.  
         [0012]     While the above-mentioned prior art separator and feeder apparatus accomplishes the task of separating one product from a stack of products and transferring it to a rotating drum, it has certain limitations that limit the speed of operation of the machine. For example, since the sucker bar is positioned underneath the stack in the prior art, in order for the sucker to clear the leading edge of the paper in time, the sucker bar must swing down (counterclockwise in  FIG. 1 ).  
         [0013]     In addition, in order for the sucker bar  6  to position the leading edge of the product accurately for proper pick-up by the gripper  7 , the sucker bar must pivot all the way down, such that the “final,” extended position of sucker  5  is almost touching the rotating drum. In other words, the distance that the sucker must “travel” is the entire distance between the bottom side of the lowermost product in the stack and the uppermost periphery of the drum. Since there are mechanical limits on how quickly the sucker bar can be pivoted back and forth, the necessity for the sucker to make a “full travel” limits the speed at which products can be separated from the stack and transferred to the drum. This full travel requirement also increases the amount of time that suction must be applied to the sucker, and also increases wear and tear on the sucker bar. In addition, this arrangement requires the drum to have a relatively large diameter, placing limits on the rotational speed of the drum. Consequently, the above disadvantages place an upper limit on the speed of the entire machine. It is desirable to overcome these limitations, particularly in machines such as newspaper insert machines, where extremely high speeds are required.  
       SUMMARY OF THE INVENTION  
       [0014]     To overcome the limitations of the prior art, an improved product separator and feeder apparatus and method has now been developed which is capable of separating flat products from a stationary stack of flat products, and transferring and feeding each product individually to a drum or other moving parts of a machine, efficiently and at extremely high speeds.  
         [0015]     In order to accomplish this, the separator and feeder apparatus of the present invention employs a unique, specially-positioned pivoting and articulating sucker bar, having several degrees of motion, operating in timed relationship with a unique reciprocating and articulating pusher blade, to reduce the travel distance of vacuum suckers and to increase the speed at which products are separated from a stack and transferred to a rotating drum, for subsequent transfer to a moving pocket.  
         [0016]     More specifically, one embodiment of the invention comprises an apparatus for separating and feeding flat products from a stack of flat products, comprising: 
        a pivoting and articulating sucker bar having at least one sucker mounted thereon, the sucker bar arranged to pivot around a cam profile mounted to one side of and above a lowermost product in the stack, the sucker arranged to periodically pivot up, articulate toward and make contact with a leading edge of such lowermost product and then to pivot down, articulate away and pull down and away such edge by suction to create a gap between such lowermost product and a next lowermost product in the stack; and     a reciprocating and articulating pusher blade arranged to push into such gap, and articulate down, in timed relationship with the sucker bar, to further separate such lowermost product from such next lowermost product, and to push down such leading edge to bring such edge to within range of a gripper.        
 
         [0019]     Another embodiment of the invention comprises a method for separating and feeding a flat product from a stack of flat products, comprising the steps of: 
        pivoting a sucker about a cam profile located to a side of a stack of flat products, and articulating the sucker toward the stack, until the sucker makes contact with the bottom of a lowermost product in the stack;     applying vacuum to the sucker;     pivoting the sucker down, and articulating the sucker away, from the stack, to create a gap between the lowermost product and a next lowermost product in the stack, and to begin to pull down and away a leading edge of the lowermost product;     pushing a blade into the gap to engage the top of a leading edge of the lowermost product;     releasing the vacuum from the sucker; and     articulating the blade downwards so as to push the leading edge of the lowermost product down and away from the stack and to within range of a gripper.        
 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]     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:  
         [0027]      FIG. 1  is a side view of a prior art separator and feeder apparatus;  
         [0028]      FIG. 2  is a perspective view of the product separator and feeder of the present invention;  
         [0029]      FIG. 3  is a top view of the invention;  
         [0030]      FIG. 4  is a side partial sectional view of the invention, taken along lines A-A of  FIG. 3 ;  
         [0031]      FIG. 5  is a side partial sectional view of the invention, taken along lines B-B of  FIG. 3 ;  
         [0032]      FIG. 6  is a side sectional view of the invention, showing the invention mounted adjacent to a rotating drum of a product feeder; and  
         [0033]      FIG. 7  is a timing diagram showing time relationships of motions of the pusher tip, sucker cup and sucker crank of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0034]     The following description disclosed an embodiment of the present invention that is particularly useful for separating flat paper products, such as newspapers, newspaper inserts and jackets, from the bottom of a stationary stack of flat products, and transferring them at high speeds to a rotating drum of a product feeder, for subsequent delivery to open moving pockets on a linear conveyor of a newspaper insert machine. The invention is not, however, limited to such use and is usable in any environment where separation and transfer of individual flat items from a stack of flat items to another moving machine part is necessary or desirable.  
         [0035]     Turning now to the drawings,  FIG. 2  is a perspective view of the product separator and feeder of the present invention. The separator and feeder includes an approximately box-shaped frame  12  of metal or other suitable rigid material, on which is mounted a table  14  suitable for holding a stack of flat items such as paper sheets  80  ( FIG. 5 ). An optional jogger plate  100  ( FIG. 6 ) may also be included adjacent to the table.  
         [0036]     Rotatably mounted under the table  14  and preferably within the frame  12  is a drum  15  ( FIG. 6 ) mounted on a drum drive shaft  62 , which is driven by an electric motor (not shown). Preferably mounted around the periphery of the drum are a plurality of grippers  85  ( FIG. 6 ).  
         [0037]     Referring to  FIG. 2 , in a feature of the invention, mounted within the frame and preferably oriented parallel to the drum drive shaft  62  is a pivoting and articulating sucker bar  30  and an associated sucker bar drive shaft  34 , also oriented parallel to the drum drive shaft. Attached to the sucker bar is at least one sucker  32 . Preferably, multiple suckers are employed. The sucker bar is arranged to pivot around a pivot point or profile  50 , and also to articulate up and down. (See also  FIG. 4 .)  
         [0038]     Sucker bar  30  is rigid and hollow and is suitable for supplying vacuum and air to the suckers. A flexible hose (not shown) is attached between the sucker bar and a vacuum and air manifold (not shown). Preferably, the suckers are rubber, cup-shaped and suitable for forming a seal between the sucker and a sheet of newspaper or other flat item when vacuum is applied to the sucker and the sucker is brought into contact with the item, preferably from below. The purpose of the suckers is to grab and pull down and away a leading edge of the lowermost sheet in the stack during a separating and feeding operation.  
         [0039]     In another feature of the invention, and unlike product separators and feeders in the prior art, the pivot points or areas of sucker bar  30  are not located under the table  14  holding the stack of flat products  80 . Instead, the sucker bar is pivotally and articulably mounted within the frame sideways away from the table and the stack. More particularly, in  FIGS. 2 and 5 , it can be seen that sucker bar  30  is mounted to the left of, and not under, table  14 , and approximately horizontal in relation to leading edges (toward the left in this view) of products in the stack (see  FIG. 5 ).  
         [0040]     In yet another feature of the invention, and as best seen in  FIGS. 2 and 5 , the sucker bar has more than one degree of motion. Not only does the sucker bar pivot about an axis parallel to the axis of rotation of the drum, but the sucker bar also articulates up and down, perpendicular to the pivoting axis, within elongated slots  31  in the frame ( FIG. 2 .). This arrangement further reduces the travel distance required for the attached sucker(s) to pivot and articulate toward and away from the lowermost product  81  ( FIG. 5 ) in the stack, permits the sucker vacuum to be released earlier, and permits the drum diameter to be decreased, thus further increasing the speed of product separation and  
         [0041]     As best seen in  FIG. 4 , mounted to both ends of sucker bar drive shaft  34  are sucker bar cranks  35  and associated pulleys  36 . Each crank  35 , in turn, is pivotally attached to one end of a hinged, articulating sucker bar control lever  40 . Hinge point  41  in the approximate middle of each control lever  40  is fixedly mounted to one end of the sucker bar drive shaft, and other end of the control lever  40  is pivotally mounted to the frame  12  at pivot points  50 . Crank  35 , lever  40 , hinge point  41 , and pivot point  42  together define a cam profile about which sucker bar  30  travels when it is in motion.  
         [0042]     In another feature of the invention, mounted to frame  12 , and as best seen in  FIGS. 3, 5  and  6 , is a pusher blade mount  71 , on which a pusher blade  70  is mounted so as to reciprocate and articulate when in motion. A major purpose of pusher blade  70  is to push into a gap between the lowermost sheet  81  in the stack and the second lowermost sheet after the suckers  32  have pulled down and away the leading edge of the lowermost sheet, and then to push the leading edge down further toward rotating drum  15  ( FIG. 6 ) until the leading edge is within range of an open gripper  85  mounted on the periphery of the drum. As can be seen in  FIG. 6 , grippers  85  pivot back and forth as the drum rotates. The solid line shows the grippers in their fully retracted position, and the dashed line shows the grippers in their fully extended position.  
         [0043]     Pusher blade  70  is positioned close to sucker bar  30  ( FIGS. 2 and 5 ) and preferably approximately midway between opposite sides of the frame, and in between the suckers, so as to avoid interference with the suckers during operation, and so as to provide for an even push-down of the product toward the drum.  
         [0044]     As shown in  FIGS. 5 and 6 , pivotally attached to pusher blade  70  is a crank  75  that is also attached to pusher blade drive shaft  34 .  
         [0045]     In the preferred embodiment, and as best seen in  FIG. 4 , sucker bar drive shaft  34  and pusher blade drive shaft  74  are rotatably driven in synchronization with the drum  15  by means of a belt or chain  60  that loops around a pulley or gear  63  ( FIG. 6 ) mounted on the drum drive shaft  62 , then around an idler wheel  91 , around a sucker bar drive shaft pulley or gear  36 , then around a pusher bar drive shaft pulley or gear  67 , and back around the drum drive shaft pulley  63 .  
         [0046]     In operation, as the drum rotates (counterclockwise in  FIGS. 5 and 6 ), a vacuum is periodically created in a manifold (not shown) through a vacuum inlet (not shown). Sucker bar  30  then pivots (counterclockwise in  FIGS. 5 and 6 ), and also articulates up and down within slot  31 . As the suckers  32  approach the leading edge of the lowermost sheet  81 , a vacuum is applied to the suckers  32  through the sucker bar. The leading edge of the lowermost sheet is engaged by the suckers. The suckers then pivot down and away, thus pulling the leading edge of the lowermost sheet down and away from the stack, and creating a gap between the lowermost sheet and the next lowermost sheet. After a brief interval, air is then blown into the manifold through an air inlet to release the vacuum in the suckers. This permits the suckers  32  to alternatively grab and release the leading edge of flat items such as a paper inserts from a stationary table  14  or hopper area, for transfer to the pusher blade and later to the rotating drum. After release of the vacuum, the pusher blade is pushed into the gap between the lowermost and next lowermost sheets, and then articulated down to push the lowermost sheet further away from the next lowermost sheet, and within range of the grippers  85  on the rotating drum. As the grippers move within range, the grippers grab the leading edge of the lowermost sheet, and pull the sheet down and partially around the periphery of the drum. A short time later, the grippers are released, and the sheet is released into a moving pocket on a conveyor.  
         [0047]      FIG. 7  is a timing diagram showing preferred time relationships of motions of the pusher tip, sucker and sucker crank of the invention. The horizontal axis shows degrees of rotation of the drum. At position 0 degrees, the sucker starts to pivot upward and articulate toward the lowermost sheet in the stack of paper. After approximately 150 degrees of rotation, the sucker has engaged the leading edge of the lowermost sheet, has separated it from the underside of the stack, and is starting to pivot and articulate down and away from the stack. At this point, the tip of the pusher blade engages the lowermost sheet and starts pushing the sheet toward the drum. Vacuum is also released from the sucker at this point, or slightly before this point, and the sucker pivots rapidly downward.  
         [0048]     Between positions of approximately 180 degrees and 270 degrees, while the pusher blade is still pushing the lowermost sheet toward the drum, the sucker begins to reverse direction and move toward the stack in preparation for engaging the next lowermost sheet in the stack. This is a significant feature of the invention in that this arrangement and method of operation permits two sheets to be handled at the same time. Specifically, before the pusher blade has finished pushing the lowermost sheet down to within range of the grippers, the suckers are already moving toward the next lowermost sheet, or have already engaged the next lowermost sheet.  
         [0049]     In summary, the present invention provides several advantages over the prior art. First, the sucker bar and pusher blade work in coordinated fashion in multiple ways to separate each product from a stack of products. This reduces the stroke distance of the sucker. The short stroke of the cups allows for decreased response time and increased speed. The sucker movement, pusher blade movement, and vacuum and air operations are all carefully timed and coordinated with the movement and operation of the drum and the grippers to facilitate the quick separation and feeding of flat material.  
         [0050]     Using the present invention, it has been discovered that the sucker need travel only about ⅓ of the distance between the stack and the drum. Also, the vacuum can be released from the sucker sooner, and thus disengage the sucker from the paper sooner so that the sucker can move out of the way and prepare to engage the next sheet in the stack. And since the pusher blade is to the side of, and hence out of the way of, the suckers, the suckers can start to pivot up toward the next sheet in the stack while the pusher blade is still pushing the first sheet down toward the drum. Consequently, the coordination of the parts of the present invention permits the parts to work together to provide multiple ways to increase the speed of product separation and feeding, and hence to increase the overall speed of the entire machine.  
         [0051]     Although only one embodiment of the present invention has been expressly disclosed, it is, nonetheless, to be broadly construed, and not to be limited except by the character of the claims appended hereto.