Conveyors: power-driven – Conveyor system for establishing and moving a group of items – By shifting group from row conveyor onto row conveyor
Reexamination Certificate
2001-05-21
2003-04-15
Bidwell, James R. (Department: 3651)
Conveyors: power-driven
Conveyor system for establishing and moving a group of items
By shifting group from row conveyor onto row conveyor
C198S430000, C198S418500
Reexamination Certificate
active
06547058
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to a conveyor system comprising a row former, an array rake and a palletizing sweep mechanism that are arranged in series and are specifically designed to convey objects having irregular cross section shapes. In particular, the present invention pertains to a conveyor system comprising a novel row former, a novel array rake and a novel sweep mechanism that are all designed to prevent relative movement between objects arranged in rows and then formed in two dimensional arrays of the objects as the objects are moved through the conveyor system, where the objects have triangular shaped cross sections.
2. Description of the Related Art
Conveying systems for conveying objects, for example light-weight blow molded plastic bottles, typically include portions of the conveying system that quickly convey one or more single file streams of the objects from one station of the conveying system to another station, for example from a blow molding station where the plastic bottles are formed to a downstream palletizing station where the blow molded plastic bottles are arranged on pallets. Conveying systems often include infeed conveyors that convey one or more single file streams of the objects to a row former. The row former includes pairs of spaced, parallel arms or bars that define a row forming slot between each pair arms for each stream of objects conveyed by the infeed conveyor. The arms are positioned above the infeed conveyor where the slots between the arms receive a number of objects from the streams of objects conveyed by the infeed conveyor and arrange the numbers of objects in rows. With the desired number of objects filling the slots of the row former, the conveyed streams of objects are held back by gates of the infeed conveyor. The row former, with the arranged rows of objects, then moves in a direction perpendicular to the rows of objects across the infeed conveyor and onto the accumulating table surface. The arms of the row former then stop and move upwardly from the accumulating table surface, leaving the numbers of objects in the first arranged rows on the accumulating table surface.
The row former is then moved in the opposite direction back across the accumulating table surface to its position in line with the infeed conveyor. The row former is then moved downwardly aligning the slots between the pairs of arms of the row former with the streams of objects held back on the infeed conveyor. The gates of the infeed conveyor are opened and the slots between the arms of the row former are again filled with numbers of objects conveyed by the conveyor, upon which the gates of the conveyor are closed. The movement of the row former described above is then repeated, leaving numbers of objects in the second arranged rows on the accumulating table surface. This movement of the row former is repeated in forming two dimensional arrays of the objects on the accumulating table surface.
The accumulating table typically includes an array rake that moves across the surface of the table, engaging with the formed array of objects and pushing the formed array of objects over the table surface in the conveyor path direction toward a palletizer. The array rake is typically an elongated bar that extends across the surface of the accumulating table in a direction perpendicular to the conveyed path direction. The rake is moved by chain conveyors that cause the rake to travel across the accumulator table surface, pushing a formed array of objects before the rake across the table surface. When the rake has completed its movement across the table surface, the chain conveyor then moves the rake through its return cycle beneath the table surface before returning the rake to the accumulator table surface to engage with and push the next array of objects formed on the table surface by the row former. The accumulator rake is often used to move a formed array of objects over the accumulator table surface to a position where a sweep mechanism of a palletizer can be clamped over the formed array of objects.
The sweep mechanism of the palletizer is comprised of four panels arranged in a rectangular configuration that are positioned over the formed array of objects on the accumulating table surface. The four panels are moved downwardly over the array and pivot toward each other to clamp around the array of objects formed on the table surface. The sweep mechanism then moves the formed array of objects over the accumulating table surface as a layer of objects to be stacked on a pallet by a palletizer.
Prior art row formers, accumulating table rakes and sweep mechanisms have worked well in arranging numbers of conveyed objects in rows and then positioning the rows side-by-side in forming two dimensional arrays of the objects, and then sweeping the arrays of objects as layers of objects to be palletized where the objects being formed into the arrays are symmetric about their center vertical axes. Plastic blow molded bottles and other such containers that are symmetric about their center vertical axes are examples of such objects. With each of the individual objects in an arranged row being symmetric about its center vertical axis, it did not matter if the object was rotated or caused to move slightly about its center axis as the row former pushed the rows of objects across the infeed conveyor and onto the row accumulating table surface, or as the arrays of objects were moved across the accumulating table surface by the rake or sweep mechanism because the relative orientations of the objects would remain unchanged. However, difficulties were encountered in arranging rows of objects and in forming the rows of objects into two dimensional arrays of the objects when the shapes of the objects changed from the conventional shape, symmetric about its center axis, to asymmetric shapes, for example a plastic, aluminum or cardboard container having a triangular cross section.
A side view of one example of a container
10
having a triangular cross section is shown in FIG.
1
. The container is basically comprised of a hollow triangular body
12
having an enlarged base
14
at its bottom and an enlarged rim
16
around a top opening of the container. In forming rows of these containers
10
, single file streams of these containers would be supplied to the slots between the row former arms with the containers of each stream of containers being positioned relative to each other as shown in the schematic representations of the positions of the containers in FIG.
2
.
FIG. 2
shows the relative positions of the containers in four streams of containers supplied by the infeed conveyor to the four slots of a row former. As seen in
FIG. 2
, adjacent containers of each of the four rows of containers are rotated 180 degrees relative to each other to maximize the number of containers that can be arranged in each row of the row former. However, although the arrangements of the containers in each row shown in
FIG. 2
maximizes the numbers of containers occupying each row of the row former, problems arose when the rows of containers were moved from the row former onto the accumulating table surface of the conveyor system and the arms of the row former were removed from between the rows of the containers.
When the rows of containers formed by the row former and moved to the accumulating table surface in two dimensional arrays such as that shown in
FIG. 2
were pushed across the accumulating table surface by the forward arm of the row former, or by subsequent rows of containers formed by the row former, or by the array rake of the accumulating table, the point contact between the apexes
18
of the containers in one row with the side walls
20
of the containers in an adjacent row would cause containers to move away from the relative positions shown in FIG.
2
. This was primarily due to the instability caused by the single point contact of the apex
18
of each container in one row pushing against or being pushed by the middle of a side wall
20
of
Bidwell James R.
Ouellette Machinery Systems, Inc.
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