Abstract:
A system for metering articles (C) includes staging conveyor ( 16 ) and a transfer conveyor ( 26 ) extending along a conveyor path. The transfer conveyor ( 26 ) has at least two independent sets of conveying elements ( 44, 48 ). The system also includes a supply unit and a control unit ( 40 ). A first set of conveying elements ( 44 ) is held stationary at the loading zone while a first group of articles is supplied from the staging conveyor to the loading zone. Thereafter, the first group of articles (C) is moved to the exit point. The control unit also controls a second set of conveying elements ( 48 ) such that after the first group of articles is moved from the loading zone, the second set ( 48 ) is held stationary at the loading zone while a second group of articles is transferred from the staging conveyor to the loading zone.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to a system for metering articles such as containers, more specifically, but not exclusively, the invention relates to an apparatus for and method for metering articles during a container-fining process. 
         [0002]    The filling of articles such as beverage containers is typically performed using high-speed equipment. Open-top containers are conveyed sequentially to a filler which is used to dispense liquid into the containers. Modern fillers typically operate at high speed, often filling multiple containers simultaneously as the filler rotates while the containers move along a circular path. This provides sufficient “dwell” time for each container at the filling nozzle without requiring that the container be slowed or stopped. An example of such a filler may be seen in U.S. Pat. No. 5,924,482. The filled containers are then conveyed to other equipment used for closing the containers, loading the filled containers into packages, and the like. 
         [0003]    Ahead of the filler, the empty containers must be arranged in a linear fashion and transported at a line speed consistent with the filler speed. The empty containers may be supplied to the filling line on pallets in a stacked configuration, in which ease it is necessary for the empty containers to be unloaded from the pallet and placed onto a conveyor in an arranged fashion for transport to the filler. This task may be done manually, which requires a person to perform a repetitive, tedious task. What would be desirable would be to provide automated equipment that can unload the containers from the pallet and supply them to the filler. 
         [0004]    Similar needs exist in the industry with respect to beverage manufacturing and packaging, as well as in other arts. For example, it may necessary to direct the tilled containers from the filler area to a packaging machine that arranges the containers into groups of predetermined number and then packages them in a paperboard carton or other package. Equipment is needed to form the groups and to direct the groups into the packaging machine at appropriate speed. Similar needs exist for handling other articles. 
       SUMMARY OF THE INVENTION 
       [0005]    In accordance with the present invention, an article metering system for metering a plurality of articles such as containers includes staging means for holding a plurality of articles, and a conveyor extending along a conveyor path from a loading zone to an exit point and back to the loading zone. The conveyor has at least two independent sets of conveying elements for moving articles along the conveyor path. Supply means is provided for supplying a group comprising a predetermined number of articles from the staging means to the loading zone. A control means controls the sets of conveying elements whereby a first of the sets is held stationary at the loading zone while a first group of articles is supplied from the staging means to the loading zone, and is thereafter controlled to move the first group of articles to the exit point. The control means also controls a second set of conveying elements such that after the first group of articles is moved from the loading zone, the second set is held stationary at the loading zone while a second group of articles is transferred from the staging means to the loading zone. 
         [0006]    The control means may further control the second set of conveying elements to move the second group of articles to the exit point, and may further control the first set of conveying elements such that after the second group of articles is moved from the loading zone, the first set is returned to the loading zone. 
         [0007]    The control means may further control the sets of conveying elements such that if a croup of articles is not present at said loading zone, the waiting set of conveying elements is held stationary at said loading zone only a predetermined period before being moved to said exit point. 
         [0008]    Alternatively, the control means further control the sets of conveying elements such that if a group of articles is not present at said loading zone, the waiting set of conveying elements is held stationary at said loading zone until a group of articles becomes present at said loading zone. 
         [0009]    Optionally, the or each other of said sets of conveying elements are held stationary on said conveyor during the stationary period of said waiting set of conveying elements. 
         [0010]    Optionally the groups of articles may be supplied in layers from the staging means to the loading zone in order to minimize or eliminate empty space between groups of containers at the loading zone. 
         [0011]    Preferably the article metering system comprises a transfer element disposed at the exit point of the conveyor for receiving a metered stream of articles and for transferring said metered stream of articles to a processing device. 
         [0012]    Preferably the article metering system comprises a delivery mechanism for delivering a plurality of articles to the staging means. 
         [0013]    According to a second aspect, the invention provides, a method of metering articles, such as containers, comprising providing a plurality of articles to a staging means: conveying said plurality of articles from a loading zone to an exit point using at least two independent sets of conveying elements; supplying a group comprising a predetermined number of articles from said staging means to said loading zone; and controlling said sets of conveying elements whereby a first of said sets is held stationary at said loading zone while a first group of articles is supplied from said staging means to said loading zone, and is thereafter controlled to move said first group of articles to said exit point, and for controlling a second set of conveying elements such that after said first group of articles is moved from sale leading zone, said second set is held stationary at said loading zone while a second group of articles is transferred from said staging means to said loading zone. 
         [0014]    Preferably, the step of controlling further comprises controlling said second set of conveying elements to move said second group of articles to said exit point, and for further controlling said first set of conveying elements such that after said second group of articles is moved from said loading zone, said first set is returned to said loading zone. 
         [0015]    Alternatively, said step of controlling further comprises controlling the sets of conveying elements such that if a group of articles is not present at said loading zone, the waiting set of conveying elements is held stationary at said loading zone only a predetermined period before being moved to said exit point. 
         [0016]    Optionally, the step of controlling comprises controlling the or each other of said sets of conveying elements such that they are held stationary on said conveyor during the stationary period of said waiting set of conveying elements. 
         [0017]    Optionally, the step of controlling further comprises controlling the sets of conveying elements such that if a group of articles is not present at said loading zone, the waiting set of conveying elements is held stationary at sale loading zone until a group of articles becomes present at said loading zone. 
         [0018]    Preferably, the method comprises supplying groups of articles in layers from the staging means to the loading zone in order to minimize or eliminate empty space between groups of containers at the loading zone. The method may further comprise transferring a metered stream of articles from the exit point to a processing device. Optionally, the method further comprises delivering a plurality of articles to the staging means. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  shows a perspective, partially schematic view of a container metering system in accordance with the present invention. 
           [0020]    FIGS.  2  and  4 - 7  are each a perspective, partially schematic view of the container metering system shown in  FIG. 1 , showing sequential, further steps in its process of operation. 
           [0021]      FIG. 3  is a perspective, broken-away and partially schematic view of the transfer conveyor of the system of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    A machine embodying the article metering system of the present invention is shown in  FIG. 1 . A pallet  10  that includes stacked layers of articles such as open-top, empty beverage containers is moved into the proximity of the machine along a roller conveyor  12 . A de-palletizing robot  14  having a programmable arm is used to lift a layer of containers C from the pallet  10  and to place it onto a staging conveyor  16  comprising a series of retaining elements  18  which are moved around a conveyor. Elements  18  form an array of receiving apertures, each capable of holding a container C. The staging conveyor  16 , which forms a portion of a staging means for the containers, advances in the direction shown by arrow  20 , being moved in an intermittent motion that presents a first row  22  of containers C at the forward end of conveyor  16 , stopped in the position shown in  FIG. 1 . 
         [0023]    Other staging means that present the containers C in an organized, predictable manner may be used. For example, the containers may be held on the pallet  10  in stacked trays, with an entire tray being removed from the pallet and placed in position for subsequent handling. 
         [0024]    Referring now to  FIG. 2 , the first row  22  of containers C is engaged by a transfer means which includes lifting means  46  that engages the top of each container C of row  22 , e.g., by vacuum, and lifts the row  22  from staging conveyor  16  and places the row of containers C onto the loading zone of a transfer conveyor  26 . Transfer conveyor  26  includes a series of container-engaging elements  28 , each configured so as to engage a single container C in a recessed lace so that movement of element  28  will result in movement of the container C. 
         [0025]    Referring now to  FIG. 3 , a portion of transfer conveyor  26  is shown schematically. The transfer conveyor  26  includes a plurality of chains, three chains  30 ,  32 , and  34  being shown in this embodiment. The three chains  30 ,  32 , and  34  are stacked in vertical alignment so that, with respect to horizontal, each moves along the same path. Each chain  30 ,  32 ,  34  is driven by a separate motor M 1 . M 2 , and  1 V 13  respectively. Each motor M 1 , M 2 , and M 3  are preferably programmable servo motors, so that while each chain  30 ,  32 , and  34  move along essentially the same path, shown generally by arrow  36 , each may be drivers independently of the others. Each engaging element  28  is connected to one (but only one) of chains  30 ,  32 , and  34  in such a manner that the engaging element  28  moves in a path around conveyor  26  that is identical to that of the other engaging elements regardless of which chain  30 ,  32 , or  34  the particular element  28  is connected to. 
         [0026]    Motors M 1 , M 2 , and M 3  are all operated under the control of a programmable control means  40 . Control means  40  is conventional in its construction. The programming of control means  40  to accomplish the operation of motors M 1 , M 2 , and M 3  as described herein will be readily understood by those skilled in the art. 
         [0027]    Referring back to  FIG. 2 , engaging elements  28  are arranged on the conveyor  26  in sets of engaging elements  28  disposed in a side-by-side arrangement along the path of conveyor  26 . The number of engaging elements  28  in each set corresponds to the number of receiving apertures provided in each row of staging conveyor  18 , and the number of sets corresponds to the number of independent but coincident chains comprising conveyor  26 . In the embodiment shown herein, three such sets of engaging elements  28  are provided. A first set  44  is positioned at the loading zone, adjacent to the exit end of the staging conveyor  18 , with the engaging elements  28  that form set  44  being aligned with the receiving apertures of the leading row of the conveyor  18 . 
         [0028]    Lifting means  46  transfers the group of containers C from the leading row on the staging conveyor  18  onto the loading zone of transfer conveyor  26 . The lifting means  46  may be, e.g., a vacuum system that engages the containers C, lifts them together as a row from the receiving apertures  18  of the staging conveyor  16 , arm places them or transfer conveyor  26  so that one container C is located in the receiving recess of each engaging element  28 . The containers C are shown in this position in  FIG. 2 . Other forms of transfer means may be used, such as a belt conveyor that, intermittently directs articles onto fixed guides that in turn direct the articles onto transfer conveyor  26 . 
         [0029]    Referring now to  FIG. 4 , it can be seers that the engaging elements  28  of set  44 , and the conveyed containers G, are advanced along transfer conveyor  26 . This occurs by selective actuation of the corresponding one of motors M 1 , M 2 , and M 3 , so that each engaging element  28  moves the corresponding container C. A static guide  48  retains the containers on the path of conveyor  26 . Meanwhile, a second set  50  of elements  28  is advanced along the transfer conveyor  26  by actuation of a second of the motors M 1 , M 2 , and M 3  for the purpose of locating the set  50  at the exit end of the staging conveyor  16 . At the same time, the lifting means  46  begins to lift the next row of containers C from the staging conveyor  16 . 
         [0030]    in  FIG. 5 , it can be seen that the elements of set  50  are brought to a stop at the end of staging conveyor  18 , where the containers of the next row are placed by the lifting means  46  into the recesses defined by the elements  28 . Meanwhile, set  44  of elements  28  continues to advance its respective containers C along the transfer conveyor  26 . A third set  52  of elements  28 , driven by a third of motors M 1 , M 2 , and M 3 , is moved towards the loading zone at the end of staging conveyor  16 . 
         [0031]    As shown in  FIG. 6 , the containers C conveyed by the first set  44  of elements  28  continue along the path of transfer conveyor  26  until the containers C reach the exit point of conveyor  26 , where they begin to engage stationary guide  54  and an infeed conveyor  56 . In this embodiment infeed conveyor  56  may include a screw-type conveyor element  58  having a pitch that is sized to receive a container C within each flight of the screw-type conveyor element  58  so as to advance the containers C along the infeed conveyor  58  and away from the transfer conveyor  26 . 
         [0032]    Referring now to  FIG. 7 , the containers C that had been delivered to the infeed conveyor  56  by the first set  44  of elements  28  have traversed the length of infeed conveyor  56 , whereupon they move around a starwheel device  60  and are transferred onto a filling apparatus, illustrated schematically at  62 . Meanwhile, the elements  28  of the first set  44  are returned along the return path of transfer conveyor  26 . In  FIG. 7 , the elements  28  are shown approaching the loading zone at the end of the staging conveyor  16 , where the elements  28  will be available for loading with additional containers C. The second set  50  of engaging elements  28  is unloading its respective containers C into the infeed container  56 , which containers C will join the line of containers C previously deposited by the preceding set. At the same time, the third set  52  is proceeding along transfer conveyor  26  so that any conveyed containers C can be directed into the infeed conveyor  56 . 
         [0033]    Throughout the sequence shown by FIGS.  2  and  4 - 7 , it can be seen that the de-palletizing robot  14  is progressing to move the next layer of containers C from the pallet  10  onto the staging conveyor  16 . For maximum efficiency of operation, it will be appreciated that layers of containers should be supplied to staging conveyor  16  so as to minimize or eliminate empty space between containers C on the conveyor  16 , although the container metering system can accommodate breaks in the supply of containers C. In one embodiment, when a set  44 ,  50 , or  52  of elements  28  arrives at the exit end of staging conveyor  16  and no containers C are present, the set will wait the normal time increment and then proceed around conveyor  26  even though the elements  28  may be empty. Alternatively, the control system  40  for motors M 1 , M 2 , and M 3  may be programmed so that the set  44 ,  50 ,  52  will simply wait at tire loading point for containers C to arrive from staging conveyor  16 . In this latter case, some containers C may be halted on the conveyor  26  until additional staged containers C reach the loading zone. 
         [0034]    While the container metering system is described herein as used as part of a container filling operation, it will be appreciated that the invention may be used in any operation in which it is desired to take articles delivered in bulk and supply them in metered fashion to a subsequent operation. For example, the system could be used to take filled, individual containers delivered on pallets and supply them to the infeed of a packaging machine for placing the filled containers into a carton. Alternatively, the system could be used to supply articles of any type to, for example, a processing station where the articles are painted or labeled. Many other uses will be apparent to those skilled in the art. 
         [0035]    In addition it is envisaged that any set of engaging elements held stationary at the loading zone so that a group of containers can be loaded into the set of engaging elements  46 ,  48 ,  50  will be held stationary only relative to the group of articles and in absolute terms both the group of articles and set of conveying elements may be moving but relative to one another are both stationary. It is also envisaged that alternatively, the group of elements will only be held substantially still or will be allowed to move, providing that the movement relative to the group of containers C enables loading of the group of containers into the set of engaging elements  46 ,  48 ,  50 .