Material or article handling – Apparatus for moving intersupporting articles into – within,... – Unstacking apparatus
Reexamination Certificate
1998-05-20
2001-01-09
Ellis, Christopher P. (Department: 3651)
Material or article handling
Apparatus for moving intersupporting articles into, within,...
Unstacking apparatus
C198S444000, C198S689100, C198S575000
Reexamination Certificate
active
06171051
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for separating a stack of documents, such as, for instance, a stack of magazines, into individual documents.
In practice, there is a regular need to unstack stacks of documents, such as, for instance, magazines, so that individual documents are obtained. In the following, a document is understood to mean not only a magazine, but also a book, a video cassette, a compact disk, a postal item or a like information-carrying object. In the case of magazines, for instance, it is customary for the retailer to return to the publisher the magazines that have not been sold by the end of the day, week or month for which they are intended. Needless to say, the retailer does not first sort the magazines, but returns them to the publisher in often random stacks. Depending on the number of returned magazines and the price of the various magazines which have been returned, the publisher settles with the retailer. It is therefore essential that it be determined how many magazines of each type have been returned by the retailer. Determining these numbers manually is an impracticable task. Specifically, unstacking a random stack of magazines of different types presents a major problem. The object of the invention is to provide an apparatus and a method for separating a stack of documents into individual documents.
EP-A-0 478 981 discloses a method and an apparatus for separating a stack of documents. The known apparatus comprises a horizontal endless conveyor and an inclined roller conveyor. The rollers of the inclined roller conveyor are individually drivable, so that the mutual distance between the documents to be separated is controllable. Apart from the fact that the known apparatus is rather costly, the chances that a proper separation occurs are not particularly high. A first drawback of the known apparatus is that it works exclusively on the basis of the frictional force between the lowermost document resting on the rollers of the roller conveyor and the rollers. This frictional force is dependent on the mass of the document. Specifically with light documents, the frictional force will be small and the chances of the document not being carried along by the inclined roller conveyor are considerable. A second disadvantage of the known apparatus is that the angle of inclination of the roller conveyor in the known apparatus may not be too steep because otherwise the frictional force between the rollers and the underlying document will be too small. For the known apparatus, an angle of inclination of 20° is proposed. Such an inclination is rather gentle. The tendency of the overlying documents to slide down is therefore not all too strong. The known apparatus will therefore be unable to accomplish a proper separation in all types of documents. Moreover, the known apparatus can work only at a relatively low processing rate.
SUMMARY OF THE INVENTION
The apparatus contemplated by the invention should be applicable to all types of documents, that is, both very light and very heavy documents.
To that end, according to the invention, the apparatus for separating a stack of documents into individual documents comprises a number of endless conveyors which are arranged behind each other, connect to each other, and together form a transport path, the transport path comprising a first path section and a second path section, and in the first path section the stack of documents is formed into a shuffled document stream, and in the second path section the documents are separated from the shuffled document stream into individual documents, while at least one of the endless conveyors is inclined, and at least the or each inclined conveyor includes a vacuum chamber and an endless conveyor belt provided with suction openings, the vacuum chamber including a suction opening contiguous to the side of a top part of the conveyor belt remote from a transport surface. Owing to the apparatus comprising two path sections where, separately, two properly controllable operations occur, that is, forming a stack of documents into a shuffled document stream and subsequently separating the documents disposed in the shuffled document stream into individual documents, the separation of the documents can be realized in a controlled manner.
Owing to the inclined conveyors comprising a vacuum chamber and an endless conveyor belt provided with suction openings, excellent adherence between the conveyor belt and the underlying document is created during the transport on the inclined conveyors. As a consequence, a fairly steep angle of inclination for the inclined conveyors can be chosen, which promotes the degree of separation occurring on the inclined conveyors. What is further achieved through the vacuum chamber conveyors is that both very light documents and very heavy documents can be effectively separated. Because the inclined conveyors can have a fairly steep angle of inclination, the separation will occur very fast. The fact is the overlying documents will slide down fairly rapidly off the underlying document being sucked against the surface of the inclined conveyor belt. As a consequence of this fast separation, a travelling speed of about 2 meters per second can be achieved, which, in the case of A
4
products, amounts to a capacity of about 4 products per second. Such a capacity is absolutely unattainable with the known apparatus.
In order to obtain a properly shuffled document stream, the apparatus is characterized, according to a further elaboration of the invention, in that the first path section comprises a first conveyor, arranged substantially horizontally as viewed in a direction of transport, and a second conveyor, which is inclined, so that, viewed in the direction of transport, it defines an ascending transport path section, a supply end of the second conveyor connecting to a discharge end of the first conveyor, while for forming the shuffled document stream the transport speed of the second conveyor is equal to or higher than the transport speed of the first conveyor.
In order to form a stream of individual documents from the shuffled document stream in a controlled manner, according to a further elaboration of the invention, the second path section includes a third conveyor, arranged substantially horizontally as viewed in the direction of transport, and the second path section further includes a fourth conveyor, which is inclined, so that, viewed in the direction of transport, it defines an ascending transport path section, a supply end of the fourth conveyor connecting to a discharge end of the third conveyor, while for separating the documents from the shuffled document stream the transport speed of the fourth conveyor is higher than the transport speed of the third conveyor.
Preferably, the two above-described preferred embodiments are combined with each other in that a supply end of the third conveyor connects to a discharge end of the second conveyor.
In order to arrive at a proper separation of the documents, according to a further elaboration of the invention, above at least some of the endless conveyors a sensor is arranged by means of which the passing documents are sensed, and the transport speed of at least some conveyors is controllable, the apparatus comprising a control which, depending on a document stream sensed by the sensors, controls the transport speed of the different conveyors.
Needless to say, the substantially horizontally arranged conveyors, too, can be provided with an endless conveyor belt and a vacuum chamber as indicated above.
With an apparatus of such design, documents of different dimensions and different thicknesses contained in a single stack can be efficiently separated from each other.
The invention further relates to a method for separating a stack of documents, such as, for instance, a stack of magazines, into individual documents. According to the invention, in a first method step the stack of documents is formed into a shuffled document stream, which document stream has a first, optionally variable, transpo
Buyze Martijn
Hamers Ludovicus Wilhelmus Alphonsus
Birch, Stewasrt, Kolasch & Birch, LLP
Buhrs-Zaandam B.V.
Dillon, Jr. Joe
Ellis Christopher P.
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