Material or article handling – Process – Of moving intersupporting articles into – within – or from...
Reexamination Certificate
1999-11-12
2001-10-02
Krizek, Janice L. (Department: 3652)
Material or article handling
Process
Of moving intersupporting articles into, within, or from...
C414S798700
Reexamination Certificate
active
06296437
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to sortation conveying systems used to fulfill orders of intermingled articles such as assortments of books, video cassette containers, packaged software, compact disk containers or the like. More specifically, the invention relates to discharge stacking stations that stack orders of articles onto an accumulation tray from which attending workers remove the articles and pack the orders for distribution.
BACKGROUND OF THE INVENTION
In large distribution applications, sortation conveying systems are often used to fulfill orders of intermingled articles such as assortments of books, video cassette containers, packaged software, compact disk containers, etc. Workers load articles into the system and the articles are conveyed in single file on a core conveyor belt for the sortation conveying system. As the assorted articles move along the core conveyor belt in single file, the system reads bar code information on each respective article. Based on this information, a programmable computer instructs the system with respect to further downstream processing and assorting of articles into various outgoing orders. The downstream end of the sortation conveying system normally includes a system of computer controlled diverting gates that divert articles into appropriate discharge stacking stations for outgoing orders. Outgoing orders typically contain 100 or more articles. Workers take the articles from the respective stacking station, and pack the orders for distribution. If an article is loaded onto the core conveyor and is not needed for any of the outgoing orders, it is diverted into a leftover bin. These types of sortation conveying systems are particularly effective in large distribution applications because order fulfillment and sortation are electronically integrated, thus substantially reducing the likelihood of human error in fulfilling the orders.
It is important to note that stacking the sorted articles minimizes damage to the articles being handled. For example, diverting articles into bins creates substantially more damage than stacking the orders.
The present invention was developed by the assignee of this application in order to foster more efficient mechanical handling of articles in the discharge stacking stations. In particular, it was desirable to develop a stacking station that was able to efficiently handle and move articles with the articles standing upright on edge, and without allowing the articles to tip. Importantly, it is desirable that this be done at speeds sufficiently high so that the operation of the stacking stations does not create an efficiency bottleneck for the overall system. In addition, it is desirable that the stacking stations dispense orders in a manner that is convenient and accessible for workers to unload.
SUMMARY OF THE INVENTION
The invention is a discharge stacking station that automatically stacks selected articles sequentially onto a substantially horizontal accumulation tray such that the articles are standing upright on edge and in series side-by-side, thus rendering the unloading of the articles from the accumulation tray convenient and efficient. The accumulation tray preferably includes an inclined bottom wall (e.g. downward inclination of 15°-30°), and a back wall extending perpendicularly upward. The accumulation tray is disposed substantially horizontally between a loading end of the tray and an unloading end of the tray.
The invention involves the use of a reciprocating stacking member located at the loading end of the accumulation tray. The reciprocating stacking member has a floor that is disposed to move above a small portion of the accumulation tray located at the loading end of the tray. The reciprocating stacking member also preferably has a backstop wall that extends upward perpendicularly from the floor. It is preferred that the reciprocating stacking member effectively nest next to the bottom wall and the back wall of the accumulation tray such that the floor of the reciprocating stacking member slides adjacent a portion of the bottom wall of the accumulation tray and the backstop wall of the reciprocating stacking member slides adjacent a corresponding portion of the back wall of the accumulation tray. A stationary stop member is located generally above the floor of the reciprocating stacking member and is disposed generally perpendicular to the accumulation tray. A chute transfers selected articles from the core conveyor in singular fashion onto the reciprocating stacking member when the reciprocating stacking member is positioned in an article receiving position. Preferably, a photoelectric sensor senses the passing of articles from the chute onto the reciprocating stacking member. After the article is transferred onto the reciprocating stacking member, the reciprocating stacking member is retracted. As the reciprocating stacking member moves towards the stationary stop wall to the retracted position, the stationary stop wall pushes the article from the floor of the reciprocating stacking member, and the article drops on edge onto the accumulation tray. The reciprocating stacking member then returns to the article receiving position, and in doing so, the reciprocating stacking member incrementally pushes the articles previously stacked on the accumulation tray towards the unloading end of the tray. This process is repeated for each article selected to be stacked onto the tray until the order is filled, or alternatively, the accumulation tray becomes full.
As mentioned, it is preferred that the reciprocating stacking member include a floor as well as a backstop wall extending perpendicularly upward from the floor. It is desirable that the wall thickness for both the floor and the backstop wall be in the range between ¾ of an inch to 1 and ½ of an inch. It has been found that this configuration effectively prevents back-tipping of the stacked articles. It is also preferred that the discharge stacking station include a dead plate for preventing tipping of the first stacked articles on the accumulation tray. Preferably, the dead plate is connected to a linear motion actuator, such as an automatically controlled pneumatic cylinder, that is able to drive the dead plate along the length of the accumulation tray between a home position located near the reciprocating stacking member and a full range position located near the unloading end of the tray. Before the first article is stacked on the accumulation tray, the dead plate is positioned near the loading end of the accumulation tray by the reciprocating stacking member. Then the pneumatic cylinder is deactivated (i.e., the dead plate is connected to a dead cylinder). As the articles are stacked on the accumulation tray, the dead plate abuts the first stacked article to prevent front tipping of the article in the accumulation tray. As additional articles are stacked on the accumulation tray, the dead plate moves incrementally along the accumulation tray. It has been found that the use of dead cylinder provides the dead plate with sufficient resistance to prevent tipping of the articles in the accumulation tray during the stacking procedure, yet does not interfere with the stacking of the articles onto the accumulation tray. When the order is complete or the accumulation tray is full, the attending worker unloads the articles from the accumulation tray. After the articles have been unstacked, the linear actuator (i.e. the pneumatic cylinder) automatically returns the dead plate to the home position ready to accept the next order being stacked on the accumulation tray. In many applications, it may be desirable toreplace the dead plate with a combined pushing mechanism and dead plate as disclosed incopending patent application Ser. No 09/439,863, filed on Nov. 12, 1999 entitled. “Combined Pushing Mechanism and Dead plate” assigned to the assignee of the present application, incorporated herein by reference.
Various other features and objects of the invention may be apparent to those skilled in the art upon inspecting
Eggebrecht Todd R.
Knas Jason M.
Remsing David A.
Andrus Sceales Starke & Sawall LLP
Dorner Mfg. Corp.
Krizek Janice L.
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