Abstract:
An apparatus and method for uniformly and rapidly stacking one or more comestible portions provided on carrier sheets is described. Such carrier sheets are often used as a separator sheet after stacking. In the apparatus of the invention, linear slide platform fingers intermesh with an o-ring acceleration conveyor. The comestible portion and carrier sheet are delivered onto the intermeshed fingers while constantly being driven forward by the acceleration conveyor. As the linear slide pulls the fingers away from the acceleration conveyor, it accelerates rapidly and causes the comestible portion and carrier sheet to engage separator bars which cause the comestible portion and carrier sheet to fall into a uniform stack.

Description:
[0001]     The benefit of U.S. Provisional Application No. 60/778,984 filed on Mar. 3, 2006 is hereby claimed for this application. 
     
    
     FIELD OF INVENTION  
       [0002]     The present invention relates to an automatic stacking system for the stacking of multiple comestible portions distributed on carrier sheets  
       BACKGROUND OF THE INVENTION  
       [0003]     In the food industry, a great many food products are portioned into one or more units and placed on a carrier sheets and then stacked one on top of the other prior to placing into a final container for sale. To facilitate the removal of individual portions (one or more items) the portioned comestible portions are packaged so that individual portions are separated by the carrier sheets for easy access further keeping comestible portions from sticking together.  
         [0004]     The major drawback to the current system and method of stacking portioned comestible portions on the carrier sheets is that it is highly labor intensive. Several other inventions have tried to automate the stacking of portioned comestible portions on carrier sheets with limited or no success. Many failures include: 1) the inability of maintaining the portioned arrangement on the carrier sheets; 2) the comestible portion sliding off the carrier sheets when stacking; and 3) the difficulty in creating uniform stacks of products on carrier sheets at higher stacking rates of up to 100 or more portions per minute. In addition, the automatic stacking apparatus and method of the present invention eliminates the problem of repetitive motion syndrome associated with manual labor. The apparatus and method of this invention also provides an efficient method of producing uniform stacks of portioned comestible products on carrier sheets, while maintaining both the arrangement and placement of each portion. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  is a side elevation view of an automatic stacking system in accordance with the invention with the horizontal linear slide rack fingers intermeshed with the acceleration conveyor 0-ring belts.  
         [0006]      FIG. 2  is a top elevation view of the automatic stacking system of  FIG. 1  showing the horizontal linear slide rack fingers intermeshed with the acceleration conveyor 0-ring belts.  
         [0007]      FIG. 3  is a side elevation view of the automatic stacking system showing a comestible portion on carrier sheet advancing onto the horizontal linear slide rack fingers extended between the acceleration conveyor belts of  FIG. 1 .  
         [0008]      FIG. 3A  is a front elevation view along A-A′ of  FIG. 3  of the separator showing the horizontal linear slide rack fingers extending forward outward between the stationary vertical separator bars.  
         [0009]      FIG. 4  is a side elevation view of the automatic stacking system at a slightly later time than displayed in  FIG. 3  showing a comestible portion on carrier sheet advancing sufficiently further onto the horizontal linear slide rack fingers so as to engage the stop bars on the fingers.  
         [0010]      FIG. 5  is a side elevation view of the automatic stacking system at a slightly later time than displayed in  FIG. 4  showing a comestible portion on carrier sheet completely supported by the horizontal linear slide rack fingers which have been partially retracted.  
         [0011]      FIG. 6  is a side elevation view of the automatic stacking system at a slightly later time than displayed in  FIG. 5  showing the horizontal linear slide rack fully retracted and the comestible portion on carrier sheet in the process of falling down to form another stack layer.  
         [0012]      FIG. 7  is a side elevation view of the automatic stacking system at a slightly later time than displayed in  FIG. 6  showing the horizontal linear slide rack repositioned with its fingers intermeshing with the accelerator conveyor, and the previously handled comestible portion on its carrier sheet now forming the top layer of the stack.  
         [0013]      FIG. 8  is a side elevation view of the automatic stacking system with optional second lower horizontal linear slide platform stacker located beneath the first top horizontal linear slide platform with two portions already stacked in an intermediate stack on the lower horizontal linear slide platform stacker.  
         [0014]      FIG. 9  is a side elevation view of the automatic stacking system of  FIG. 8  showing a comestible portion on carrier sheet advancing onto the top horizontal linear slide rack fingers extended between the acceleration conveyor belts of  FIG. 8 .  
         [0015]      FIG. 10  is a side elevation view of the automatic stacking system of  FIG. 8  at a slightly later time than displayed in  FIG. 9  showing a comestible portion on carrier sheet advancing sufficiently further onto the top horizontal linear slide rack fingers so as to engage the stop bars on the fingers.  
         [0016]      FIG. 11  is a side elevation view of the automatic stacking system of  FIG. 8  at a slightly later time than displayed in  FIG. 10  showing a comestible portion on carrier sheet completely supported by the top horizontal linear slide rack fingers, which have been partially retracted, thereby bringing the comestible portion on carrier sheet into contact with the separator plate.  
         [0017]      FIG. 12  is a side elevation view of the automatic stacking system of  FIG. 8  at a slightly later time than displayed in  FIG. 11  showing the top horizontal linear slide rack fully retracted and the comestible portion on carrier sheet in the process of falling down to form another stack layer on the lower horizontal linear slide rack fingers.  
         [0018]      FIG. 13  is a side elevation view of the automatic stacking system of  FIG. 8  at a slightly later time than displayed in  FIG. 12  showing the top horizontal linear slide rack repositioned with fingers intermeshed between the belts of the acceleration conveyor and the previously handled comestible portion on carrier sheet forming the top layer of the stack on the lower horizontal linear slide rack fingers.  
         [0019]      FIG. 14  is a side elevation view of the automatic stacking system of  FIG. 8  at a slightly later time than displayed in  FIG. 13  showing a comestible portion on carrier sheet advancing onto the top horizontal linear slide rack and the lower horizontal linear slide rack retracted thereby permitting the intermediate stack to fall onto the lower conveyor which may then move the stacked products on carrier sheets aside. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]     Comestible food portion  2 A is dispensed by appropriate means well known in the art onto carrier sheets  2  that are then stacked by the device of this invention. Referring to  FIG. 1  and  FIG. 2 , the automatic stacking system generally comprises an o-ring type acceleration conveyor  3  having spaces  3 A between the several separate o-rings/belts  4 , a horizontal linear slide platform stacker  6  with protruding fingers  6 A and a stack takeaway conveyor  11 . The acceleration conveyor  3  is typically supplied with food portions  2 A on carrier sheets  2  from an initial conveyor device  1  and conveys product in the same direction as conveyor device  1 . The overall movement direction is indicated by heavy arrows. Acceleration conveyor  3  has a linear conveying speed greater than the linear conveying speed of initial conveyor  1 . As portions  2 A on carrier sheets  2  arrive at and transfer to acceleration conveyor  3 , the increased speed of acceleration conveyor  3  creates a larger gap or distance between sequential carrier sheets  2 . This larger distance essentially spreads out in time the arrival of carrier sheets  2  at the end of conveyor  3  in order to provide more time for stacking.  
         [0021]     The horizontal linear slide platform stacker assembly  6  comprises: a) protruding fingers  6 A; b) stops  6 B, which are angled toward the unmounted ends of fingers  6 A, mounted on fingers  6 A; c) a mounting block  6 C to which fingers  6 A are secured; d) horizontal linear slide support rods  6 D; e) a horizontal drive rod  6 E; and e) a linear servo motor assembly  6 F.  
         [0022]     The horizontal linear slide platform stacker mounting block  6 C may be advanced by linear servo motor assembly  6 F so that fingers  6 A pass between and slightly below the top of the separate o-ring belts  4  of acceleration conveyor  3  such that approximately 50% of finger  6 A length, as measured from angled stops  6 B to the end of fingers  6 A, is intermeshed between acceleration conveyor belts  4 .  
         [0023]     The stacking operation will now be described by reference to  FIG. 3  through  FIG. 6 . After each stacking operation, the horizontal linear slide platform stacker is repositioned as shown in  FIG. 2  to await the next carrier sheet. In  FIG. 3 , as the comestible food portion  2 A and carrier sheet  2  moves along acceleration conveyor  3  approaching the end of the conveyor, a photo eye sensor  12  detects the presence of the carrier sheet  2  and activates the linear servo motor assembly  6 F. In  FIG. 3 , as carrier sheet  2  arrives at the end of the acceleration conveyor  3 , carrier sheet  2  is transferred to horizontal linear slide platform fingers  6 A. The slide platform linear motor assembly  6 F starts to retract the slide platform mounting block  6 C in a direction away from the end of acceleration conveyor  3  at an initial rate of an equivalent or slightly slower speed than the speed of acceleration conveyor  3 . Acceleration conveyor  3  continues to push the comestible portion  2 A on carrier sheet  2  onto fingers  6 .  
         [0024]     Due to the motion of acceleration conveyor  3 , the forward momentum of portion  2 A and carrier sheet  2  aids in transferring the portion  2 A and carrier sheets  2  onto fingers  6 A and further causes carrier sheet  2  to advance on fingers  6 A until halted by angled stops  6 B as shown in  FIG. 4 . Angled stops  6 B create a reference stop position for stacking by preventing the portion  2 A and carrier sheet  2  from sliding off fingers  6 A. As the portion  2 A on carrier sheet  2  is approaching fingers  6 A or being transferred onto fingers  6 , the initial rate of retraction by linear servo assembly  6 F may be varied based upon the speed of the acceleration conveyor  3  which may be monitored by a conveyor speed sensor built into motor  9 .  
         [0025]     When linear motor  6 F has retracted fingers  6 A so that portion  2 A and carrier sheet  2  are past the end and clear of rollers  5  of acceleration conveyor  3 , linear motor  6 F increases the rate of retraction of fingers  6 A to a faster speed of approximately five or more times the initial retraction rate. During this accelerated retraction, as fingers  6 A are withdrawn through separator bars  8  on support  7  (see  FIG. 3A  taken along section A-A′), portion  2 A and carrier sheet  2  engage bars  8  which prevent portion  2 A and carrier sheet  2  from moving further. Separator bars  8  are positioned to extend vertically between horizontal fingers  6 A.  FIG. 5  shows portion  2 A and carrier sheet  2  just before engagement with separator bars  8 . The rapid withdrawal of fingers  6 A from underneath now stationary portion  2 A and carrier sheet  2  causes portion  2 A and carrier sheet  2  to drop under the influence of gravity onto stack  10  waiting on takeaway conveyor  11  as shown in  FIG. 6  and  FIG. 7 . Since each successive portion  2 A and carrier sheet  2  is brought to the same position against bars  8  before being dropped, a uniform stack  10  is formed on takeaway conveyor  11 . Alternatively, rather than having the portions  2 A and carrier sheets  2  stacked directly on conveyor  11 , a suitable packaging structure such as a container with open top (not shown) may be positioned below the drop point into which the portion  2 A on carrier  2  maybe stacked.  
         [0026]     In cases where it is desirable to stack a higher volume of portions  2 A and carrier sheets 2 per minute, an optional second horizontal slide platform assembly  16  may be located below the top first horizontal slide platform as shown in  FIG. 8 . In similar fashion to the top stacker assembly, the second horizontal slide platform assembly  16  consists of fingers  16 A, mounting plate  16 B, drive rod  16 C, and linear motor  16 D. Fingers  16 A pass through separator plate bars  17 . No stops are used on fingers  16 A since portions  2 A and carrier sheets  2  are already uniformly stacked by operation of the top slide platform stacker. The second lower horizontal slide platform assembly  16  is used to accumulate a specified number of portions  2 A and carriers  2  in an intermediate stack  18  under the first top slide platform  6  before fingers  16 A are withdrawn against separator bars  17  thereby dropping the entire stack to waiting takeaway conveyor  11 . This allows the takeaway conveyor  11  more time to move slowly for packaging. More than two horizontal slide platform assemblies may be employed if necessary.  
         [0027]     It is envisioned that this system will work with portions that may be provided without carrier sheets. It is further contemplated that the takeaway conveyor belt could be a solid flat belt or one with flighted raised cleats spaced to accommodate the portion size and sequenced by the completion of a stack count or by utilizing a belt with a weight controller.  
         [0028]     While only portions of the support frames have been shown in the Figures, it is well understood by those skilled in the art that all the elements of the stacking system including the conveyors, conveyor motors, control systems, linear motors, and separator bars are mounted to one or more support frames which maintain the relative positions of the stacking elements with respect to each other.