Conveyors: power-driven – Conveyor system for arranging or rearranging stream of items – By laterally or vertically moving successive items in...
Reexamination Certificate
1998-11-06
2001-03-20
Hess, Douglas (Department: 3652)
Conveyors: power-driven
Conveyor system for arranging or rearranging stream of items
By laterally or vertically moving successive items in...
Reexamination Certificate
active
06202828
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to the field of automated conveyor systems, and, more particularly, to conveyor systems used for changing the direction and orientation of transported product.
For mass production of printed media, conveyor systems are used to transport product between workstations where a variety of operations are performed as part of the production process. It is often necessary, however, to position the product on the conveyor system in a particular orientation to facilitate the execution of a particular operation. Consider paper products, for example. Product is conveyed out of the folding unit of a printing press with the fold on the side. That is, the fold is parallel with the transport direction. When the product is delivered to a stacking machine or for one of the operations of an in-line trimming machine, however, the folded edge must be leading (i.e., perpendicular to the transport direction). To perform this reorientation, drop turn systems are used in which a conveyor is positioned at a right angle to the transport conveyor carrying the product stream to reorient the product stream through redirection.
Existing conveyor systems used in reorienting product through product flow redirection suffer from the disadvantage that product often becomes misaligned or unevenly distributed during the 90° transfer. Product distribution can be critical depending on the application. For example, stacking machines include a counting device to ensure the stack is quantisized properly. If product units overlay one another, the count generated will be incorrect resulting in an inaccurate stack to be delivered to a customer. If too much product is contained in a stack, excess printing cost is incurred. If too little product is in a stack, all customers may not be served. If product is severely misaligned, the stacking machine could jam resulting in increased maintenance costs. Similar jams can occur in in-line trimmers.
Generally, alignment problems are most acute when the drop turn system is running very slow. Under slow speed, product tends to roll or misalign during the transfer from one conveyor to a perpendicular conveyor. Existing drop turn systems have been ineffective at reorienting product streams running at slow speed without incurring frequent alignment problems. Additionally, when running at very high speeds, a traditional drop turn system can also fail.
Accordingly, there exists a need for a conveyor system capable of changing product orientation through redirection of product flow at right angles that overcomes the aforementioned disadvantages of prior art systems.
SUMMARY OF THE INVENTION
Certain objects, advantages and novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned with the practice of the invention.
To achieve the advantages and novel features, the present invention is generally directed to a conveyor drop turn system for reorienting product through redirection of product flow at a substantially perpendicular angle. The drop turn system is comprised of a first product supply conveyor that, with the assistance of a vacuum control system, delivers product to a second conveyor that is substantially perpendicular to the first product supply conveyor.
In accordance with an aspect of the present invention, a third spreader conveyor is interposed between the first product supply conveyor and the second conveyor that can be adjusted to cause product to separate in a conveyance direction defined by the second conveyor. More specifically, the third spreader conveyor comprises a plurality of endless belts that can be terminated to a variety of positions on a pair of cylindrical pulleys. Through an appropriate arrangement of the belts on the pulleys, product flow can be delivered directly or an offset can be introduced by angling the belts between the pulleys. This offset allows the spreader conveyor to begin separating the product in the direction defined by the perpendicular conveyor before the product is transferred to the perpendicular conveyor. This has proven particularly effective for lightweight or flimsy product that tends to overlay itself during the transfer to the perpendicular conveyor.
In accordance with another aspect of the present invention, the vacuum control system maintains the product in a stable stream until an individual unit is ready for transfer, in its entirety, to the second conveyor thereby reorienting the product through redirection at a substantially right angle. This is accomplished by using a vacuum to hold the product in engagement until a unit is ready for transfer to the second conveyor. Thus, a unit is never in contact with both the second conveyor and the first product supply conveyor or the third spreader conveyor at the same time, which can result in undesired twisting and misalignment of the product particularly at slow or very high speeds. Thus, the vacuum control system provides the conveyor drop turn system according to the instant invention with the ability to be used in both high speed and, most importantly, low and very high speed applications where traditional conveyor drop turn systems have been ineffective.
The invention can also be viewed as providing a method for turning product. In this regard, the method can be broadly summarized by the following steps: Product is transported on a first product supply conveyor. The product is then engaged by a vacuum control system and then deposited on a second conveyor that is substantially perpendicular to the first product supply conveyor.
REFERENCES:
patent: 3608895 (1971-09-01), Kalven
patent: 4193491 (1980-03-01), James et al.
patent: 4986730 (1991-01-01), Wetter
Hess Douglas
Jaketic Bryan
Thomas Kayden Horstemeyer & Risley LLP
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