Patent GB-1360518-A (GB)
Title: Method for the destination control of objects fed into a distri buting conveying system and distributing conveying system for performing such method
IPC: B65G47/49
Filed: 1972-03-01
Abstract: 1360518 Selective signalling ALEX LINDER GmbH 1 March 1972 [12 March 1971 28 Jan 1972] 9472/72 Heading G4H Discharge of objects (e.g. containers) from a recirculating conveyer is controlled using a store indicating three items of information for each object, viz. (a) destination station, (b) section of track currently occupied by the object, a section being the stretch of track between two successive stations, (c) the position number of the object in the order of all objects in the track section. The store may be a recirculating shift register, each position being wide enough to hold items (a) and (b), item (c) being indicated by the order of occurrence of the stored items (a) and (b) for the different objects, in the shift register. The stations are scanned in turn, repetitively, and as each is scanned, the register is circulated at least once. Arrival of an object at a station is detected, e.g. photo-electrically, and if the first entry in the register which has the corresponding item (b), and thus corresponds to this object, has item (a) corresponding to this station, a discharge control signal is sent to the station and the entry in the register is erased. Otherwise, item (b) of the entry is updated to reflect the passage of the object to the next track section, and stored in the register at an appropriate position to indicate the new item (c). Recirculation in the register is via a one-entry register which can be by-passed, permitting erasure and also closing up of gaps in the register. Entry of an object into the conveyer system at a station is prevented by a lock until a suitable position is free in the shift register. Entry may be via a stand-by (lead-in) track, with a lock at each end, an entry being provided in the shift register for each object in the stand-by track. Detectors are provided at each end of this track, and in the path down which objects are discharged. from the conveyer at the station, permitting sufficient clearance to be maintained between adjacent objects. The operator, on supplying an object to the system at a station, enters the required destination on a dial or keyboard, and this may be compared with all valid destinations in turn, lack of agreement with any of them preventing entry (using the lock) or causing routing to a particular collecting station. The stations communicate with the control circuitry via a common set of lines, or via respective lines. An associative store may replace the shift register, in which case item (c) is stored explicitly. The conveyer may have a plurality of branches which diverge from each other and subsequently join up again, the stored items (a) having two portions, one identifying the branch and the other the station within the branch, switching of the objects to the appropriate branch (at a station where branches diverge) being controlled by extra comparisons using the stored items. Different types of conveyer system, running at different speeds if desired, each with its own store &c., can be linked at interchange stations, the respective stores being linked via one-entry transfer stores. The shift register or associative store in a given system may also hold information to control by-pass in case of disturbances, or preferential routings at peak-load times. Empty containers can be kept circulating in the system with an item (a) equal to zero, and discharged when necessary by producing a discharge signal on a "compare equal" with zero. Admittance of further empty containers to the system can be blocked when a predetermined number is present, and in the case of linked conveyer systems empty containers can be automatically transferred between systems to maintain an approximate balance.