EP1611042A1

EP1611042A1 - Folding cylinder for sheet-like material and folder apparatus making use of said cylinder

Info

Publication number: EP1611042A1
Application number: EP04721983A
Authority: EP
Inventors: Renzo Tommasi
Original assignee: TAU MACHINES Srl
Current assignee: TAU MACHINES Srl
Priority date: 2003-03-28
Filing date: 2004-03-19
Publication date: 2006-01-04
Anticipated expiration: 2024-03-19
Also published as: PL1611042T3; EP1611042B1; ATE446271T1; DE602004023705D1; ITFI20030085A1; SI1611042T1; ES2335006T3; WO2004085301A1

Abstract

A folding cylinder (1) for sheet-like material (M), for cooperating with a cutting roller (3) for cutting the material (M) in sheets (F1, F2) and with a second folding cylinder (2) for picking up the sheets (F1, F2) and transversally folding them, comprising two parts (13, 14) defining in cooperation the working surface of the cylinder, one or more counter-cutting grooves (6) for cutting the material and first drive means (12) for receiving the operation from the cutting roller (3) being associated to a first (13) of said parts, while at least one deviation device (7) cooperating with the second folding cylinder (2) and second drive means (18) for transmitting the operation to a second cylinder (2) are associated to a second part (14) of the first cylinder (1). The first and the second part (13, 14) may be angularly displaced with respect to each other around the axis of the cylinder, mutual locking means (15, 16) being also provided between the parts (13, 14), which may be disengaged to permit the angular displacement.

Description

TITLE

FOLDING CYLINDER FOR SHEET-LIKE MATERIAL AND FOLDER APPARATUS MAKING USE OF SAID CYLINDER DESCRIPTION Field of the Invention

The present invention relates to the field of folding machines for sheet-like material, in particular paper, tissue paper or similar items, for the production of multi-layer paper articles such as towels, handkerchiefs, and napkins. More specifically, it concerns a cylinder and a device for the execution of transverse fold lines on a material provided in web form, possibly already longitudinally folded.

Descrizione of the Background Art According to a solution provided in the known art, such devices comprise a couple of counter-rotating cylinders, arranged with parallel axes, thereby resulting substantially tangent with respect to each other. A first cylinder receives the paper web material tangentially, and cooperates with a cutting roller for dividing the material into distinct sheets. The cut is achieved along a generatrix of mutual tangency between the cutting roller and the first cylinder, in turn mutually parallel and counter-rotating. To such end, the operative surface of the cutting roller has at least two radially-projecting cutters, arranged along respective generatrices, circumferentially equally spaced. The operative surface of the first cylinder exhibits a corresponding distribution of counter-cutting grooves, such that following to the coordinated rotation between the roller and the cylinder, the grooves and the cutters match together in the tangency area, carrying out the cut of the material. During and after the cut, the paper material is held on the surface of the first cylinder by a vacuum system. Following to the rotation of the first cylinder, the material cut in sheets is transported towards the tangency area with the second cylinder, the area in which the folding along a transverse line, i.e. parallel to that of the cut, is carried out.

In greater detail, the folding is a result of the concurrent action of radial deviation devices and gripping devices of the paper material, distributed along the working surfaces of the first cylinder (in alternating position with the counter-cutting grooves) and of the second cylinder, respectively. Also in this case the rotation of the two cylinders is mutually coordinated, so that a deviation device and a gripping device correspond in the tangency area, on opposite sides of the sheet of paper. The latter, upon operation of a deviation device, is in practice slightly raised from the surface of the first cylinder, and tucked in the gripping device, which thus become capable of grasping the material . A known device which, among many others, adopts a solution of this type is for example illustrated in U.S. Patent No. 4,822,328.

With the continuing rotation, the second cylinder, at this point gripping the paper sheet, transports it, overcoming the resistance of the first cylinder's vacuum system. The sheet is thus arranged, transversely folded, on the surface of the second cylinder, from which it may be withdrawn for possible subsequent treatments, or taken immediately for packaging.

As mentioned above, along the circumferential length of the operative surface of the first folding cylinder, coounter-cutting grooves for the cutting step are alternated with deviation devices for the folding step. Clearly, the distribution of grooves and devices (more precisely, their mutual distance measured circumferentially) determines the position of the folding line with respect to the cut edges of the sheet, and being a fixed design parameter of a given cylinder, is initially chosen depending on the requested final product . In particular, the distance between the folding line and the rear edge of the sheet may not be modified (the adjective "rear" intended with reference to the feeding direction) , corresponding to the circumferential distance between a deviation device and the groove immediately downstream. This adversely affects the flexibility and the versatility of the device, requiring the substitution of the first cylinder when its geometric characteristics are not compatible with the desired result. The production costs are increased, due both to the times of machine downtime and related manpower, and the necessity of buying and maintaining a number of replacement cylinders. Summary of the Invention

The present invention aims at overcoming the above- described problems, providing a folding cylinder for sheet-like material and a related folder apparatus which permit to vary the position of the folding line substantially as desired, in particular to achieve with a single cylinder the folding arrangements requested by all the main typologies of paper articles on the market .

Such object is achieved with a folding cylinder which has the essential characteristics defined by the first of the attached claims.

Besides, a folder apparatus according to the present invention is characterised by the features specified in claim 9.

Brief description of the drawings

Characteristics and advantages of the folding cylinder for sheet-like material and of the folder apparatus making use of said cylinder according to the present invention will be apparent from the following description of one of its embodiments, given as purely exemplifying and non-limiting, with reference to the attached drawings, in which:

- figure 1 is a schematic perspective view of the device according to the present invention, in exploded view and with parts omitted for the sake of illustrative clarity; - figures 2 and 3 represent the device of figure 1, cross-sectioned orthogonally to the rotation axes of the cylinders and in intermediate position, in two different steps of the folding operation; and

- figures 4 and 5 show the device along the lines of view/section represented respectively by the arrows IV-IV of figure 2 and by the arrows V-V of figure 3. Detailed description of the Invention

With reference to the above figures, a folding apparatus according to the invention has a general configuration corresponding to that already provided for in the known art, briefly delineated in the introductive part of the present description. In particular, a first folding cylinder 1 is visible, tangentially cooperating at one side with a cutting roller 3, and at the opposite side with a second folding cylinder 2. The cylinders 1, 2 and the cutting roller 3 rotate integrally to respective shafts la, 2a, 3a, revolvingly supported at their ends by a frame 10 (figures 4 and 5) . For operating the roller 3 a motor, not shown, is provided. The operation is driven to the first cylinder through a first gear drive 12, working between the shafts 3a and la, outside the frame 10 (as once again can be seen in figures 4 and 5) . The drive between the first and second folding cylinder will be described later on. The web material to be cut and folded is indicated at M in figures 2 and 3, and is fed to the tangency point between the cutting roller 3 and the first folding cylinder 1, with the assistance of a deviation roller 4.

Two cutters 5 are visible on the cutting roller 3, projecting along diametrically-opposed generatrices for cooperating with respective grooves 6 formed, according to an analogous arrangement, in the first folding cylinder 1. The first folding cylinder, which in any case will be described in detail further on, comprises two radial deviation devices 7, having the shape of tucker blades 7a, extending in intermediate position between the grooves 6. The devices 7 make use of technical solutions of known type, and are not therefore described in detail.

Furthermore, it is clear from the figures that the first cylinder 1 is internally hollow, defining a central chamber lb which communicates with the outside via a distribution of radial holes 8a, 8b formed in the working surface of the cylinder. A suction is exerted through the holes 8a, 8b, for holding and transporting the web material M during and after the execution of the cut, as represented in figures 2 and 3. In figure 2 in particular it may be noticed a sheet FI on the first cylinder 1, completely cut and transported to the folding area. Suction means, not shown, are provided to obtain a vacuum within the chamber lb, pneumatically communicating with the same chamber by way of the shaft la, hollow in its turn.

The second folding cylinder 2 too has overall characteristics substantially referrable to that already known, with four gripping devices 9, equally spaced along the working surface, adapted to cooperate with the deviation devices 7 as already mentioned above. In particular, in figure 2, the step is identifiable in which a deviation device 7 and a gripping device 9 cooperate to perform the folding of the sheet FI, while a sheet F2 (already folded by the gripping device that has operated previously) has been conveyed to the second cylinder 2.

Figure 3 refers instead to an immediately subsequent step, in which the sheet FI is leaving the first cylinder 1. For operating the gripping devices 9, here too according to a known solution, a cam 11 is provided, visible in figures 4 and 5, integral with the frame 10 and coaxial with the shaft 2a. The devices 9 have in fact rotating shafts 9a whose ends project axially from the cylinder 2 and come into contact with the cam 11 through respective driving arms 9b. The cam 11 is shaped in such a way that it brings the shafts 9a in a gripping position, along a predetermined arc of rotation of the cylinder 2, evidently corresponding to the sector where the transfer of the sheets from the first folding cylinder 1 occurs.

Turning back to the first folding cylinder 1, according to the invention it has a structure in two parts, angularly displaceable with respect to each other in an adjustable manner around the rotation axis of the cylinder. A first part consists of the actual cylinder body, indicated at 13 in figure 1. The body 13 is integral with the shaft la and comprises, in addition to two side flanges 13a lying on planes normal to the rotation axis, two cylindrical sectors 13b which extend axially between the flanges 13a, thereby defining only a part of the working surface of the cylinder.

More precisely, the two sectors 13b are located over two symmetric arcs in correspondence with respective grooves 6, that are formed precisely in the sectors together with a group of suction holes 8a. If the circumferential length of the body 13 is followed, the two sectors 13b are thus alternated with two passages 13c, symmetric in their turn, which open on to the inner chamber lb of the cylinder. In correspondence with the passages 13c, shaped slots 13d are formed in the side flanges 13a, so that a butterfly profile is conferred to the flanges, as can be appreciated in figures 2 and 3.

Coaxially and outside body 13, a second cylinder part is arranged, in the form of a cage 14 (figure 1) , supported by the shaft la so that the former is free for rotation with respect to the latter. The frame 14 comprises in turn two side flanges 14a which externally overlap the side flanges 13a of the body 13 and centrally define the insertion seats for the shaft la. The flanges 14a have a complete circular figure, with the same diameter of the flanges 13a, obstructing thus the slots 13d. In each flange 14a slots 15 are also formed, of curved shape which follows the profile of the flange edge, and arranged in an equally spaced manner along such edge.

The slots 15 slidingly house respective screws 16 which, inserted axially from the outside, engage within threaded holes formed in the relevant flange 13a of the body 13. The flanges 13a and 14a are connected to each other due to the coordinated tightening of the screws 16; on the other hand, by removing said tightening the flanges are capable of performing mutual angular displacements.

Two sleeves 17 project outside from -and integrally with- the two side flanges 14a of the cage 14. The sleeves 17 coaxially overlay the shaft la, being in turn free from it. At the free ends the sleeves 17 radially expand, forming respective gears 18 which engage with corresponding gears 19 of the second folding cylinder 2. In this manner, the second drive of the rotational operation, i.e. that from the first to the second folding cylinder, is ensured.

A couple of laminar coverings axially and integrally extend between the side flanges 14a of the cage 14; the coverings completely obstruct respective passages 13c of the body 13, partially inserting themselves in between them. In further detail, each covering comprises a gutterlike elongated member 14b, passing within the related passage 13c through the slots 13d, and housing a radial deviation device 7. The width of the elongated member 14b is considerably lower than the angular extension of the passage (and of the slots) , so that the above-mentioned mutual angular displacement between the flanges 13a and 14a may take place; the displacement corresponds precisely to a translation of the elongated member along the circumference of the cylinder.

For each covering, the obstruction of the passage 13c is completed by two projections 14c transversely extending from the elongated member 14b. The projections 14c are arc-shaped in accordance with the curvature of the cylindrical sectors 13b of the body 13, to which they overlap in order to provide a continuity to the working surface of the cylinder. The transversal extension (if the longitudinal axis of the elongated member is taken as a reference; or else circumferential if referred to the overall configuration of the cylinder) of the projections 14c is such that said overlapping, and therefore the continuity of the working surface, is assured along the entire angle of displacement permitted to the cage 14.

A group of holes 8b is formed in the projections 14c, in order to guarantee the necessary suction also in the portion of the working surface defined by such projections. In particular, the distribution of the holes 8b on the projections 14c, in relation to that of the holes 8a on sectors 13b, is such to permit mutual correspondence in the area in which the projections and the sectors overlap, thus assuring the suction in such area.

It shall be easily understood that, due to the above-described structure, the position of the elongated members 14b and consequently of the deviation devices 7 may be adjusted, with respect to the counter-cutting grooves 6. Such adjustment corresponds to a translation of the folding line on the folded sheet, approaching to or moving away from the rear cut edge of the sheet . As mentioned, the adjustment is obtained upon the untightening of the screws 16, so that the cage 14 can be displaced angularly with respect to the body 13 around the rotation axis of the cylinder. At the same time, there is therefore a sliding of the screws 16 within the slots 15, within the limits imposed by the length of the latter. Such length shall be established so as to assure the desired extent of adjustment range. Since the gear 18 driving the operation to the second folding cylinder 2 is integral with the cage 14, further to the adjustment the deviation devices 7 always result in phase with the gripping devices 9, while the counter-cutting grooves 6 are maintained in phase with the cutters 5 of the cutting roller 3.

Thanks to the invention it is therefore possible, with a single folder apparatus and without the need to replace any components, to vary the position of the folding line with respect to the two cut edges, thereby satisfying the most various production needs. In particular, a sheet with an off-center folding may be obtained, with flaps having a length which may be varied as desired. On the other hand, the central position of the folding with respect to the cut edges may be maintained, even when the length of the sheet varies, another result clearly precluded to the known apparatus. In this regard, it must be pointed out that the sheet length is easily modifiable by holding in greater or lesser manner the feed of the material M upstream of the first cylinder 1, and therefore causing the material to slide over the surface of the cylinder between the execution of the two cuts.

All the above is accomplished without adversely affecting in any manner the efficiency of the folding procedure, due to the fact that the first cylinder 1 always maintains a continuous and integral working surface, along with the necessary homogeneity in the distribution of the suction holes 8a, 8b. Therefore, there is provided an apparatus with the utmost flexibility and versatility, capable of significantly containing production costs, and also with a solution that is remarkable for its structural and functional simplicity. The cylinder according to the invention, even if usable in a particularly advantageous manner in an apparatus such as the one referred to above, may also be effectively used as a component of structures with different overall characteristics, if there is a similar need for a position adjustment of the radial deviation means. The construction details adopted in the illustrated embodiment, in particular but not exclusively those related to the reversible locking between the body 13 and the cage 14, may undergo modifications within the scope of an equivalent working concept. For instance, the cage 14, i.e. the so-called "second" part of the first folding cylinder 1, may also be made of several, non-integral parts, i.e. each capable of locking on the body 13 in an independent manner. Finally, it must be pointed out that, with obvious adaptations with respect to what described above, the cylinder may comprise counter-cutting grooves 6, and deviation devices 7, in number greater or lesser than two. Other variants and/or modifications may be brought to the folding cylinder for sheet-like material and to the folder apparatus making use of said cylinder according to the present invention, without thus departing from the scope of protection of the invention itself.

Claims

1. Folding cylinder (1) for sheet-like material (M) , comprising: a generally cylindrical working surface; at least one counter-cutting groove (6) , formed in said working surface, for cooperating with a cutter (5) of a cutting roller (3) for cutting in sheets (F) said material (M) ; at least one radial deviation device (7) , for cooperating with a gripping device (9) of a second folding cylinder (2) to deviate said sheets (F) from said working surface and transversely fold them; a plurality of holes (8a, 8b) formed in said working surface in order to exert a suction capable of holding said material (M) and transporting said sheets (F) over said operative surface; and first (12) and second (18) drive means capable of engaging respectively with complementary drive means in said cutting roller (3) and in said second cylinder (2) , so as to receive and transmit a rotational operation, characterised in that it comprises two parts (13, 14) defining in cooperation said surface, said at least one counter-cutting groove (6) and said first drive means (12) being formed in a first of said parts (13) , while said at least one radial deviation device (7) and said second drive means (18) are formed in a second part (14) of the cylinder (1), said first and said second part (13, 14) being angularly displaceable with respect to each other around the cylinder axis (1), locking means (15, 16) being also provided for mutually locking the parts (13, 14), said locking means being releasable so as to permit the mutual angular displacement .

2. Cylinder according to claim 1, wherein said parts (13, 14) consist respectively of a body (13) , integral with a central rotating shaft (la) of the cylinder (1) , and a cage (14) arranged coaxially and externally to said body (13) , said body (13) comprising at least one cylindrical sector (13b) defining a portion of said surface in which said at least one counter-cutting groove (6) is formed, and at least one passage (13c) communicating with a vacuum inner chamber (lb) on which said holes (8a, 8b) open; said cage (14) comprising at least one arc-shaped laminar covering (14b, 14c) obstructing said at least one passage (13c) and partially overlapping said at least one sector (13b) , respective groups (8a, 8b) of said holes being formed in said sector and said covering, so as to mutually correspond in the overlapping area.

3. Cylinder according to claim 2, wherein said covering (14b, 14c) comprises an elongated gutter-like member (14b) arranged within the relevant passage and housing a radial deviation device (7) , the width of said member (14b) being considerably lower than the angular opening of the relevant passage (13c) , thereby permitting said mutual angular displacement between the body (13) and the covering (14b, 14c) , said covering also comprising two projections (14c) projecting transversely from said member

(14b) and arc-shaped in accordance with the curvature of the at least one cylindrical sector (13b) of said body

(13) , to which they overlap, the length of said projections (14c) being such to assure said overlap, and thus the continuity of said working surface, along the entire displacement angle permitted to said cage (14) .

4. Cylinder according to claim 3, wherein said body (13) comprises two generally circular side flanges (13a) , lying on planes orthogonal to the rotation axis, among which said at least one sector (13b) axially extends, said cage

(14) in turn comprising two side flanges (14a) overlaying the side flanges (13a) of said body (13) on the outside, said at least one covering (14b, 14c) integrally extending between said side flanges (14a) of said cage (14) , passing through shaped slots (13d) formed in said side flanges (13a) of said body (13) in correspondence with said at least one passage (13c) , said locking means (15, 16) working between said side flanges (14a) of said cage (14) and said side flanges (13a) of said body (13) .

5. Cylinder according to claim 4, wherein in each of said side flanges (14a) of said cage (14) curved slots (15) are formed which follow the flange edge and are arranged in an equally spaced manner along such edge, said locking means

(15, 16) comprising means (16) for reversibly tightening to each other said side flanges (13a, 14a) of said body (13) and said cage (14) , slidingly housed by said slots

(15) .

6. Cylinder according to claim 5, wherein said tightening means comprise screw means (16) engaging within respective threaded seats formed in said side flanges (13a) of said body (13) , and tightening on the outside said side flanges (14a) of said cage (14) .

7. Cylinder according to any of the claims from 2 to 6, wherein said body (13) comprises two cylindrical sectors

(13b) over two symmetric arcs in correspondence with respective counter-cutting grooves (6) , defining two passages (13c) for housing respective coverings (14b, 14c) .

8. Cylinder according to any one of the claims from 4 to 7, wherein sleeves (17) project axially from said side flanges (14a) of said cage (14) , coaxially overlaying said rotating shaft (la) , being disengaged therefrom, said second drive means comprising respective gears (18) , integrally supported by said sleeves (17) and engaging with corresponding gears (19) formed in said second folding cylinder (2) .

9. Folder apparatus for sheet-like material comprising a first folding cylinder (1) cooperating with a cutting roller (3) and with a second folding cylinder (2) for cutting said material (M) in sheets and for transversely folding it, first and second drive means (12, 18) being provided for transmitting a rotational operation respectively from said cutting roller (3) to said first cylinder (1) , and from said first cylinder (1) to said second cylinder (2) , characterised in that said first cylinder (1) is a cylinder according to any of the previous claims, said second drive means comprising mutually engaging gears (18, 19), formed in said first cylinder (1) and in said second cylinder (2) .