Data processing: generic control systems or specific application – Specific application – apparatus or process – Article handling
Reexamination Certificate
1999-05-27
2001-01-30
Ellis, Christopher P. (Department: 3651)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Article handling
C700S230000
Reexamination Certificate
active
06181980
ABSTRACT:
FIELD OF THE INVENTION
This invention is in the field of piece good conveying and concerns a method and an arrangement for controlling conveyance and processing of piece goods.
BACKGROUND OF THE INVENTION
The term “piece goods” is a term of art which refers to a large quantity of identical or at least similar objects which are conveyed and processed in succession while being held individually or in groups. For conveying piece goods as defined above, it is usual to use conveying systems which are closed systems, i.e., conveying systems in which holding means, each holding and conveying one object or one group of objects are moved in a predetermined direction along a conveying path which is closed in itself. On this conveying path, at least one supply station and at least one removal station are provided, and in those stations objects are supplied to holding means or are removed from holding means, respectively. Between the supply station and the removal station, the conveyed holding means are loaded and their load may also be processed. Between the removal station and the supply station, the holding means are empty.
The holding means are, e.g., attached to an endless conveying chain at regular distances from each other, whereby the conveying chain runs in a chain channel and is driven by a suitable drive. However, the holding means can also be loosely connected with each other, i.e., without fixed distances between each other, or they can be individually movable along a rail system which is closed in itself without being mutually connected.
In stations through which or past which objects being held by holding means or empty holding means are conveyed, objects or holding means are acted on, e.g., supply or removal actions, handing-over actions, repositioning actions, processing actions or sensor actions for detecting characteristics of objects or of holding means. These actions are at least partly triggered by active control, either for each object or holding means being conveyed to the station, or for only a specific selection of the supplied objects or holding means, respectively. Control of such actions and synchronization of such actions with the conveying are important control functions in a system in which piece goods are conveyed and processed.
Specific problems concerning the control of conveying and processing of piece goods have, according to the state of the art, led to specific solutions. Stations in systems with a conveying chain are, e.g., controlled by means of a system clock cycle and possibly a fine cycle. For specific actions concerning specific objects or holding means, the clock cycles are counted and relevant cycle numbers are calculated for different positions along the conveying path according to their distances from a reference position. The basic element of control in such a system is the system clock cycle being correlated with the conveying speed.
In systems with very long conveying chains, an overall clock cycle control is no longer accurate enough and is therefore often replaced by local clock cycles and/or by sensor detection of holding means.
For triggering specific actions for specific objects or holding means in systems with holding means which are loosely connected to each other, or with holding means which are fully independent of each other, it is also suggested to equip each holding means with an electronic memory means containing a code or even data regarding characteristics of the held object and to provide suitable reading means for reading the code or memory contents in order to identify the holding means or to directly trigger a specific action.
All known attempts at solving the given problem are designed for specific applications and are either connected with too much effort or are too restricted in their effect for more general application.
SUMMARY OF THE INVENTION
An object of the invention is to provide a method for controlling conveyance and processing of piece goods, which method involves simple control and requires implementing devices which are not costly such that the system is not restricted as to the lengths of conveying chains or the independence of the holding means nor regarding the free selection for positions of freely selected stations along the conveying path, whereby in the stations either each supplied object or holding means or only specific objects or holding means are acted on. Additionally, when using the inventive method, costs and effort for commissioning, for cold starts, for statistical monitoring of the condition of holding means and for maintenance by replacing holding means is minimal. Furthermore, it is an object of the invention to create an apparatus for carrying out the inventive method.
Of the totality of holding means movable on a conveying path of a system in accordance with the invention, a plurality of holding means are equipped for a signaling function. Each station comprises sensor means for generating a signal when a signaling holding means is conveyed through it. Furthermore, the stations comprise internal clocking means or sensor means for recognition of holding means as well as counters for counting the time cycles clocked by the clocking means or for counting detected holding means.
A signal generated in a station when a signaling holding means passes through sets back the counter of the station and possibly causes registration or setting back to zero any momentary phase displacement between the station clock and the system or conveying clock. Between each two signaling holding means, a number of non-signaling holding means is provided, which number is to be different for each pair of successive signaling holding means. The number of holding means between a first downstream signaling holding means and a second upstream signaling holding means, which number is counted as a number of station cycles or as number of detected holding means and is stored or registered, clearly identifies the second signaling holding means (identification of signaling holding means). A current counter reading and the identification of the last passing signaling holding means clearly identify each holding means being conveyed through the reference point of a station.
For triggering actions regarding specific objects or holding means, the identification of the specific holding means is transmitted to the station. Such identification consists of set values for a current counter reading and a counter reading stored before the last counter reset. The identification is then compared in the station with the current counter reading and with the last stored counter reading until they coincide with the two transmitted set values when the action is triggered.
In stations comprising a plurality of actors spaced from each other or in stations with counter sensing and actors spaced from each other, the transmitted identification is corrected correspondingly.
As already mentioned above, the signal generated in a station when a signaling holding means is conveyed through it can also be used for storing a phase displacement between the station clock cycle and the conveying clock cycle. For this purpose, the moment of the signal is detected and stored with the help of a fine cycle partitioning of the station cycle, or the station cycle is synchronized with the signal by, for example, setting the phase displacement to zero. Such storing or resetting of a phase displacement serves for precise adjustment of action triggering to irregularities of conveyance which is especially necessary for purely cycle-controlled actions in far apart stations.
In the following it will be shown that with the method as briefly described above, all objects can be achieved in the simplest manner. As seen already from the principle of the inventive method as sketched above, clock synchronization between actions and conveying as well as identification of holding means are effected with the same means, i.e., with the help of signals generated by detecting signaling holding means and with the help of current and stored counter readings. This makes the method
Lutz Bruno
Maeder Carl C.
Ellis Christopher P.
Ferag AG
Rankin, Hill Porter & Clark LLP
Tran Khoi H.
LandOfFree
Method and system for controlling conveyance and processing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and system for controlling conveyance and processing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and system for controlling conveyance and processing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2516677