EP0731045A2

EP0731045A2 - A method and equipment for the automatic selection of large size loose reams from a stack of single sheets provided with ream markers

Info

Publication number: EP0731045A2
Application number: EP96830092A
Authority: EP
Inventors: Gianluigi Gamberini
Original assignee: Wrapmatic SpA
Current assignee: Wrapmatic SpA
Priority date: 1995-03-08
Filing date: 1996-02-29
Publication date: 1996-09-11
Also published as: IT1280217B1; ITBO950083A0; JPH08259084A; ITBO950083A1

Abstract

In the first step of a method for dividing a stack (P) of large size paper sheets (1) into reams (5), which are identified previously by markers (2) inserted into a front face (A) of the stack, at least the topmost marker (2) is deflected downwards and restrained in such a way that it will recover to assume and retain a downwardly angled configuration when subsequently released, whereupon a second step is one of advancing a knife (6) toward the front face (A) at a height (H1) not less than the height (H) of a single ream (5), as measured from the top of the stack (P). The knife (6) is elastically deformable to a degree greater than that of the marker (2), in such a way that the marker will also function as a relatively resilient locating surface along which the advancing knife (6) can slide to the point of penetrating accurately between the marker (2) and the bottom sheet (1) of the ream.

Description

The present invention relates to a method of selecting reams automatically from a stack of loose large size sheets, in which the reams are divided by markers, and to equipment for the implementation of such a method.
Among the problems experienced in the art field of papermaking, with regard in particular to large sheets (typically ISO size A0) as used for layout and design drawings and artwork generally, is that of how best to separate stacked sheets into reams for handling by the relative wrapping machinery.
Sheets of paper to be wrapped in reams are stacked, palletized and conveyed from the papermaking machine to the wrapping machine; the loaded pallet is placed on an elevator which rises automatically each time a ream (i.e. a parcel of sheets equivalent in number to one ream) is removed from the top by an operator, so that the height at which the reams are separated from the stack remains constant.
The prior art embraces essentially two methods of selecting reams from the palletized stack of sheets.
A first such method involves the use of an instrument similar to a calliper gauge, of which the measuring arms consist in a fixed reference element functioning as a stop, and a moving element resembling a blade insertable between two adjacent sheets. The operator sets the depth of the ream to be separated from the stack, according to the number and the thickness of the sheets, then, offering the reference arm to the topmost sheet, slides the gauge forward to the point at which the blade penetrates between two sheets and thus separates a ream of the selected size from the remainder of the stack beneath.
In a second method, use is made of a stacking machine such as will count off the single sheets of paper and insert a marker between one sheet and the next each time the count increases by a number corresponding to one ream; the marker is quite simply a slip of paper or similar material, coloured or otherwise, of which one end projects from the stack and a significantly large portion is retained between two adjacent sheets. Thus, it remains only for the operator to raise the part of the stack lying above the marker and direct it toward the wrapping machine.
This second method affords great precision, albeit with the drawback that the markers may not always be inserted in exactly the same position, by reason of the dissimilarities that occur both in sheet sizes and in different stacking machines.
Efforts have been made in the past to find solutions or methods such as will allow the automatic separation of a palletized stack of sheets into reams indicated by suitable markers of the type mentioned above; one example of a machine reflecting the outcome of such efforts is that disclosed by the present applicant in patent IT 1 201 601: this employs equipment affording means by which to grip and tension the markers, also a selection element, and associated with the selection element, a follower element that is hinged in its turn to a supporting element capable of movement toward and away from the stack of sheets in such a manner that the follower element can slide along each successive marker to the point of penetrating the stack at each division between successive reams.
In order to ensure reliable and accurate operation, at all events, the machine in question is dependent on a somewhat elaborate architecture incorporating elements invested with relative motion of a precise and complex nature; in locating and sliding along the tensioned marker, moreover, the slender blade of the selection element is caused necessarily to penetrate the stack above the marker, functioning as a guide, and below the bottom sheet of the selected ream, with the risk that the bottom sheet may suffer defacement or damage which though superficial may not always be acceptable.
Accordingly, the object of the present invention is to provide a method, and equipment for the implementation of such a method, whereby a single palletized stack of sheets can be separated into reams selected initially by the insertion of markers located in such a way as to divide each two consecutive reams one from another, adopting an extremely simple and effective solution.
The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which:

figs 1 to 3 illustrate steps performed by equipment capable of implementing a method for the selection of large size loose reams from a stack of sheets: fig 1 in a perspective view, figs 2 and 3 in side elevation with certain parts omitted better to reveal others.

Referring to the accompanying drawings, the present invention relates to a method of selecting large size loose reams automatically from a stack P of single sheets 1. The reams are divided one from another by a plurality of markers 2 inserted into a front face A of the stack P.
To detach a ream from the stack P of sheets 1, use is made of a selection device 3 operating in conjunction with handling means 4 by which the ream 5, preselected through the agency of selection means 6 appearing as a knife, will be distanced in a direction normal to the front face A of the stack P. The selection device has not been described and illustrated here in detail, not being strictly central to the subject matter of the present invention, though a preferred and unlimitative embodiment of such a device is discussed more fully in Italian patent application n° BO94A000371.
The aforementioned knife 6 is adjustable for height, to the end that it can be set at a nominal distance H1 from the topmost surface of the stack P corresponding to the height H of the ream 5, and capable of movement in such a way as to penetrate the stack P of sheets (see arrow F1 in fig 1) between the bottom sheet of the selected ream 5 indicated by the marker 2, and the topmost sheet of the remainder. The handling means 4 (which comprise a pair of blades illustrated in the drawings with phantom lines) are similarly capable of movement in such a manner that the selected ream 5 can be pushed and thus translated in a feed direction B extending at right angles to the aforementioned front face A of the stack P of sheets 1.
The method disclosed comprises steps whereby:

a) the topmost marker 2, which serves in practice to select the first and uppermost ream, is deflected downwards and bent as a result toward the front face A of the stack P in such a way as will constrain it to assume an essentially downwardly angled configuration when subsequently released (see fig 1);
b) the knife 6, positioned as already intimated at a predetermined distance H1 from the topmost surface of the stack P not less than the height H of the ream 5 (see fig 2), is advanced toward the stack.

As will be discernible from the drawings, the knife 6 is elastically deformable to a degree greater than that of the marker 2 (see arrow F2 in fig 1): this allows the knife 6 to slide along the marker 2 during the advancing movement described above, the marker in its turn functioning as a relatively non-deformable reference element offered to the underside of the advancing knife 6 and enabling its insertion between the marker 2 and the sheet 1, which is also favoured by the diminutive thickness of the marker. Finally, the inserted knife 6 is caused to rotate upwards (see arrow F3 in fig 3), thus facilitating the subsequent translation of the ream 5 by the handling means 4 (see arrow F4).
To ensure the marker 2 will be positioned correctly subsequent to the deflection step, the method further comprises a blowing step (see figs 1 and 2) in which the marker 2 is invested with a force applied from the bottom upwards, in the direction denoted F, and more exactly a measured force sufficient to restraighten the marker to the point of assuming the requisite downwardly angled configuration (and in a short time, so that the penetrating action of the knife 6 will be suitably swift).
The deflecting action is applied continuously, in any event, to a plurality of markers 2 arranged along the front face A of the stack P and within the operating compass of the knife 6, whereas the single markers are released thereafter one by one, each time the knife 6 advances.
Equipment suitable for implementing the method thus described will comprise substantially those elements referred to above, of which the knife 6 is supported by a relative height-adjustable structure 7 in such a way as to constitute an integral part of the overall selection device 3, and furnished also with a blade 6a of limited thickness S possessing a high degree of elastic deformability (blued steel, for example). The equipment also comprises a restraint 8 located below the blade 6a, associated with the selfsame overall structure of the selection device 3 that incorporates the height-adjustable structure 7 and positionable thus at a set distance H2 from the knife 6, of which an operative end portion 8a is disposed substantially parallel and in close proximity to the face A of the stack P.
More exactly, the restraint 8 comprises a vertically disposed plate 9 of rigid embodiment associated with the structure of the selection device 3 in such a way that it can be positioned stably, in close proximity to the stack P of sheets 1 and with the tip separated from the knife 6 by the aforementioned distance H2 so that the topmost marker 2 can always be released.
Also forming part of the equipment are blowing means, denoted 10, comprising a duct 11 through which air is directed from a remote source (not illustrated) to a point substantially coinciding with the tip of the restraint 8: in effect, the free end of the duct 11 is rigidly associated with the aforementioned operative end portion 8a of the restraint 8, and every time a marker 2 is released by the plate 9 the duct 11 will discharge a measured jet of air sufficient to elevate the projecting end slightly and bring it immediately into the ideal selection configuration, anticipating contact with the blade 6a.
The method and equipment described and illustrated are able to ensure a swift and reliable selection of reams from a stack of single sheets thanks to the particular design of the knife and the manner of its penetration, also to the guidance provided by the marker, of which the optimum configuration is assured by the combined operation of the restraint and the blowing means.
Observing the structure of the equipment, moreover, it will be seen that a selection device already affording great precision has not been changed radically from the original design but simply adapted by the addition of small improvements which enhance its effectiveness, precision and operating speed still further.

Claims

A method for the automatic selection of large size loose reams from a stack (P) of single sheets (1), in which the reams (5) are divided initially by relative markers (2) projecting from a front face (A) of the stack and the sheets (1) of each successive ream then separated from the stack by a selection device (3), operating in conjunction with handling means (4) such as will distance the single successive reams (5) from the stack in a direction normal to the front face (A), and incorporating selection means (6) embodied as a knife that is adjustable for height, positionable at a distance from the top of the stack corresponding to the nominal height (H) of the ream (5) and designed to penetrate between the bottom sheet (1) of a ream (5) resting on a relative marker (2) and the topmost of the remaining sheets in the stack (P), wherein the handling means (4) are capable of movement such as will cause the single ream (5) to be pushed and thus translated in a feed direction (B) extending at right angles to the front face (A) of the stack,
characterized
in that it comprises the steps of:
- causing at least the topmost marker (2) indicating the first and topmost ream of the stack (P) to be deflected downwards initially and bent thus toward the front face (A) of the stack (P), in such a way that it will assume an essentially downwardly angled configuration when released subsequently;

- causing the knife (6) to advance toward the front face (A) at a distance (H1) from the topmost surface of the stack (P) not less than the height (H) of the ream (5);
also in that the knife (6) is elastically deformable to a degree greater than that of the marker (2) and able thus to slide along the marker (2) during the advancing movement with the marker functioning as a relatively non-deformable reference element offered to the underside of the advancing knife (6) and enabling its insertion between the marker (2) and the bottom sheet (1) of the ream.
A method as in claim 1, wherein the release of the topmost marker (2) is accompanied by a blowing step in which the marker is invested with a force applied in a direction (F) from the bottom upwards and sufficient to ensure that the marker (2) assumes the downwardly angled configuration.
A method as in claim 1, wherein the deflection step is implemented continuously on a plurality of markers (2) arranged along the front face (A) of the stack (P) and within the operating compass of the knife (6), whilst the markers (2) are released singly and in succession with each advancing movement of the knife (6).
Equipment for implementing a method as in claims 1 to 3, comprising selection means embodied as a knife (6) carried by a relative height-adjustable structure (7) forming a part of the selection device (3),
characterized
in that the knife (6) is furnished with a blade (6a) of limited thickness (S) possessing a high degree of elastic deformability, and operates in conjunction with a restraint (8) likewise forming a part of the selection device (3), located beneath and positioned at a fixed height (H2) in relation to the blade (6a), of which at least one operative end portion (8a) is disposed substantially parallel and in close proximity to the stack (P) of sheets (1).
Equipment as in claim 4, wherein the blade (6a) of the knife (6) is fashioned from blued steel.
Equipment as in claim 4, wherein the restraint (8) is positioned at a height (H2) in relation to the blade (6a) such as will allow the release of a single marker (2), and consists in a plate (9) of rigid embodiment associated with the overall structure of the selection device (3) that incorporates the height-adjustable structure (7) and occupying a stationary position in close proximity to the stack (P) of sheets (1).
Equipment as in claim 4, further comprising blowing means (10), consisting in an air duct (11) of which the free end is rigidly associated at least with the operative end portion (8a) of the restraint (8).