WO2009139012A1

WO2009139012A1 - Cutting die cylinder

Info

Publication number: WO2009139012A1
Application number: PCT/IT2008/000322
Authority: WO
Inventors: Stefano Lazzari
Original assignee: A.C.M.C. S.R.L.
Priority date: 2008-05-15
Filing date: 2008-05-15
Publication date: 2009-11-19

Abstract

A die-holder cylinder (1) is described that comprises a cylindrical shell with holes (15B) for the insertion of rods (9) for retaining cutting dies (5) for cutting sheet material. Inside the cylindrical shell, there are members for locking the cutting die retaining rods, said locking means comprising a plurality of strips (13) movable between a locking position and a releasing position, and complete with elements that engage with said rods and displace them towards the inside of the cylinder.

Description

" CUTTING DIE CYLINDER "

DESCRIPTION Technical field

. The present invention relates to a cutting die cylinder, i.e. to a cylinder on which cutting dies for cutting sheet materials, e.g. paper, cardboard, fabrics, non-wovens, leather and fake leather, or other such products, can be locked in a variety of positions. State of the art

In many industrial applications where materials in the form of continuous sheets need to be cut along variously shaped lines, and usually along closed lines, so-called cutting dies are used, which consist of cylindrical shells on which cutting blades are installed. These shells are locked onto revolving cylinders that co-operate with anvil rollers or contrast rollers coated, for instance, with interchangeable layers an elastically flexible material, such as polyurethane. The sheet of material being cut is fed through a nip between the cutting die cylinder and the anvil roller.

One of the problems posed by this type of equipment involves the action needed to lock the cutting dies of various shapes and sizes in the required positions on the die-holder cylinder as rapidly as possible. According to a known embodiment, the die-holder cylinder is fitted for this purpose with a plurality of threaded holes with a predetermined space between them, the cutting dies being locked onto the die-holder cylinder by means of a series of screws or threaded rods that are inserted in through holes in the cutting dies and then made to engage in the threads of the holes provided on the die-holder cylinder. The ends of these rods lock the cutting die in place by engaging in seats provided for said purpose. The procedures involved for locking the cutting dies onto the die holder cylinder according to this method take a very long time, however, and demand a considerable amount of manpower.

To overcome these problems, various methods have been devised in which the locking of the rods needed to retain the cutting dies in the die-holder cylinder is done by means of actuators, typically of the cylinder-piston type, installed inside the die-holder cylinder. An example of a mechanism of this type is described in WO-A-96/26049. Other mechanisms for locking cutting dies onto die-holder cylinders are described in EP-A-0124329, WO-A-03/004227, WO-A- 9962778, and US-A-5.003.854.

All these devices have various drawbacks, including the considerable complexity and consequently high cost of the die-holder cylinder, a lack of flexibility in use and the need to use threaded holes to enable the attachment of cutting dies of complex shape, in addition to the actuator-controlled locking means. This is because the locking means controlled by the actuators are relatively widely spaced apart and in limited number (partly because of the dimensions of the actuators themselves), which frequently makes it necessary to lock a cutting die in place by means of some of the actuators on the cylinder, then completing the attachment of the die by means of additional screws or threaded rods that engage in threaded holes in the die-holder cylinder, as in the previously-described manual techniques. Summary of the invention

According to one aspect, the invention concerns a die-holder cylinder that fully or partially overcomes at least one of the drawbacks of die-holder cylinders of the known state of the art.

Basically, according to one embodiment, the die-holder cylinder comprises a cylindrical shell with holes for inserting retaining rods for cutting die used in cutting a sheet material, means being provided inside said cylindrical shell for keeping said cutting die retaining rods in position. Characteristically, according to one aspect of the invention, the die locking means comprise a plurality of strips movable between a locking position and a releasing position, said strips being provided with means for engaging with said rods and displacing them towards the inside of the cylinder. The strips are preferably all movable simultaneously between a locking position and a releasing position. In some embodiments, the strips may be ring-shaped and they may be slidingly arranged in circumferential seats. In a preferred embodiment, however, the strips are arranged in longitudinal seats that are preferably straight and that are advantageously aligned parallel to the axis of the die-holder cylinder. This structural solution is more straightforward and consequently facilitates the manufacture of the cylinder.

In some embodiments of the invention, the means for engaging with and displacing the rods include shaped slots in which the spigots of said rods for retaining the cutting dies are inserted. Each of said slots is advantageously associated with a respective first wedge-shaped surface designed and arranged so as to displace one of said spigots towards the inside of the cylindrical shell when said strips are displaced with a cutting die locking movement. Each slot is also preferably associated with a second wedge- shaped surface for ejecting the rod.

Further advantageous features and embodiments of the invention are described below and in the attached claims, which form an integral part of the present description. Brief description of the drawings The invention is further clarified in the following description and the attached drawings, which show a non-limiting practical embodiment of the invention. More in particular,

Fig. IJs an axonometric _.view _.of_. the die-holder cylinder with portions removed; Fig. 1A is a schematic side view of a die-holder cylinder with a cutting die installed and an anvil roller or counter-roller co-operating with the cutting die; Fig. 2 is a side view of the cylinder in Fig. 1 ; Fig. 3 is a longitudinal cross-section along Ill-Ill of Fig. 2; Figs. 4, 5 and 6 are respectively an axonometric new, a view from above and a cross-section along Vl-Vl of a first component of a terminal portion of a strip;

Figs. 7, 8 and 9 are respectively an axonometric view, a top view and a cross-section along IX-IX of a first component of an opposite terminal portion of a strip; Figs. 10, 11 and 12 are respectively an axonometric view, a top view and a cross-section along XII-XII of a first component of an intermediate portion of a strip;

Figs. 13 and 14 are respectively a top view and a view along XIV-XIV of a second component of a terminal portion of a strip; Figs. 15 and 16 are respectively a top view and a cross-section along

XVI-XVI of a second component of a terminal portion of a strip;

Figs,. 17 and 18 are respectively a top view and a cross-section along XVIIl-XVIII of a second component of an intermediate portion of a strip;

Fig. 19 is a longitudinal cross-section of a first terminal portion of a strip with the first and the second components coupled together;

Fig. 20 is a cross-section similar to the one in Fig. 19 in a second terminal portion of a strip;

Fig. 21 is a cross-section similar to the one in Fig. 19 or Fig. 20 showing an intermediate portion of a strip;

Fig. 22 is a front view of a disc-shaped element for anchoring the strips in place;

Fig. 23 is a cross-section through the diameter XXIII-XXIII of Fig. 22; Fig. 24 is a front view of a second disc-shaped element for anchoring the strips in place;

Fig. 25 is a cross-section through the diameter XXV-XXV of Fig. 24; Figs. 26 and 27 respectively show a top view and a cross-section along _ XXVIJ-XXVI l_ of a batten for covering a slidjng gjrooye in a strip;

Fig. 28 is a side view of a cylindrically-shaped core of the die-holder cylinder;

Fig. 29 is a cross-section along XXIX-XXIX of Fig. 28; Fig. 30 is an enlarged partial front view along XXX-XXX of Fig. 28, with some parts in cross-section;

Fig. 31 is a side view of a rod for anchoring the cutting dies to the die- holder cylinder; and

Figs. 32 and 33 are longitudinal cross-sections of a portion of a strip with a rod for anchoring a cutting die in place, shown in two different strip positions to illustrate the locking and releasing function of the rod. Detailed description of an embodiment of the invention Figs.1 to 3 show globally a possible embodiment of the die holder cylinder according to the invention, Fig.1A being a schematic side view of the die-holder cylinder complete with a cutting die and co-operating with an anvil roller coated with an elastically flexible material, which may consist, for instance, of an interchangeable polyurethane foam cladding, or the like. The die-holder cylinder is globally indicated by the numeral 1, while the numeral 3 indicates the anvil roller or contrast cylinder, 5 the cutting die, and 7 a blade on the cutting die. The anvil roller may be made in any suitable manner, e.g. such as disclosed in EP-A-1.250.988.

In Fig. 1A, the numeral 9 schematically indicates the rods for locking or anchoring the cutting die 5 to the die-holder cylinder 1, one of which is illustrated in detail and separately in Fig. 31.

The die-holder cylinder 1 consists substantially of a cylindrical shell and two ends, indicated as 1A and 1B. The cylindrical shell is composed of a substantially cylindrical core 11, shown separately in Figs. 28 to 30, on the outer surface of which there are grooves 11A (see Fig. 30 in particular). Strips 13 slide inside the grooves 11A in the cylindrical core 11, the configuration of said strips being described in more detail below.

Each groove 11A in which a corresponding strip 13 slides is closed on the side facing the outside of the cylinder 1 by a batten 15, one of which is shown separately in Figs. 26 and 27. As shown in Figs. 3, 26 and 27 in particular, each batten 15 is provided with a plurality of holes 15A for inserting screws for attaching the batten to the _cy!i_ndrical_core 11. The latter (Bg. 30) has threaded holes 11 B in which the screws for locking the battens 15 engage. In addition to the holes 15A, the battens 15 also have through holes 15B placed along their median line, in which the rods 9 for anchoring the cutting dies 5 to the die-holder cylinder 1 are inserted. One rod 9 for anchoring the cutting die to the die-holder cylinder is illustrated separately in Fig. 31 and it is described in more detail below. Inside the hollow space defined by the ends 1A, 1B and the cylindrical core 11, there are driving means that control the movement of the individual strips 13, which slide in the direction of the double arrow f13 inside the respective grooves 11A defined by the cylindrical core 11 and enclosed by the battens 15. As will emerge clearly from the description given later on, this movement enables the rods for anchoring the cutting dies to be locked or released so as to retain the cutting dies in the required position on the outer cylindrical surface of the die-holder cylinder 1.

In the embodiment illustrated, the driving means, globally indicated by the numeral 21 , comprise a first disc-shaped element 23 and a second disc- shaped element 25 juxtaposed with the ends 1A and 1B, respectively. The two disc-shaped elements 23 and 25 are connected together by beams 27 extending in a direction substantially parallel to the axis A-A. of the die-holder. . cylinder 1. The disc-shaped element 23 is shown in detail and separately in Figs. 22 and 23. It is provided with a set of teeth 23A that make the disc- shaped element 23 substantially take on the shape of a star. On the side facing towards the inside of the cylinder, the disc-shaped element 23 has a ring- shaped reinforcement 23B. Axially, there is a ho|e 23C for the passage of an axle 35 for supporting the die-holder cylinder 1. It should be noted that this axle 35 could be replaced by two shafts integrally attached to the ends 1A and 1B of the die-holder cylinder 1, or by any other suitable means for supporting the cylinder 1.

The opposite disc-shaped element 25 is attached by means of the beams 27 to the disc-shaped element 23 and presents a shape substantially equivalent to that of the latter, except that, in addition to radial teeth 25A, a reinforcement ring 25B and an axial hole 25C, similar to the corresponding parts 23A, 23B and 23C on the disc-shaped element 23, the disc-shaped ejement _.25 (shown Jn detail in Figs. 24 and 25) ι_. also has_. brackets 29 for engaging with the spindles of a plurality of cylinder-piston actuators, indicated by the numeral 31 (Figs. 1 and 3). In the embodiment illustrated, the spindles of the cylinder-piston actuators 31 are attached to the brackets 29, while the cylinders of said actuators are anchored to a plate 33 integrally attached to the cylindrical core 11. With this arrangement, the sliding or translation of the assembly comprising the disc-shaped elements 23, 25, the ties 27 and the strips 13 in relation to the cylindrical core 11 can be controlled by means of the actuators 31.

Each strip 13 engages at both ends with the teeth 23A and 25A on the respective disc-shaped elements 23 and 25, and in this manner the translational movements of the strips inside the respective grooves 11 A can be controlled by means of the cylinder-piston actuators 31.

The shape of the individual strips 13 can be clearly seen from Figs. 4 to 21, showing individual parts thereof alone and coupled to one another. More in particular, each strip is composed of two opposite end portions, shown respectively in Figs. 19 and 20, and a plurality of intermediate portions, shown in Fig,21, inserted between the end portions shown in Figs. 19 and 20. In Figs.

19 to 21 , the references 13A and 13B indicate the end portions of a given strip and..13.C one of its intermediate portions. Lt should be noted that.the number of . intermediate portions in each strip 13 can vary, based on the axial length of the cylinder 1. In another embodiment, each strip 13 can consist of a single portion, although this is less advantageous from the point of view of the cylinder manufacturing and heat treatment. In fact, these components need to be hardened and the heat treatment for said purpose is facilitated by the manufacturing said components with limited longitudinal dimensions, which makes it easy to produce cylinders 1 even of considerable axial length.

The first end 13A of a generic strip 13 consists of two components, separately illustrated in Figs. 4, 5 and 6, and in Figs.13 and 14, respectively, while Fig. 19 shows said components assembled together. With particular reference to Figs. 4 and 6, the first component of the portion 13A of the strip, indicated as 41, consists of a flat profile with a plurality of slots 41 A (see Fig. 5 in particular) of a specific shape. More precisely, each slot 41A has an expanded end 4,1 B with a diameter D and a portion 41 C extending longitudinally along the length of the component 41_j the width L of which is narrower than the diameter D. On the underside, the component 41 has sloping, i.e. wedge-shaped, surfaces 41 D on either side of each slot 41A. These wedge-shaped surfaces 41 D slope away from the outside towards the inside of the cylinder 1 , starting from the larger-sized portion 41 D towards the opposite end of each slot 41 A.

The dimensions D and L of each slot 41 A are such that the rod 9 for retaining the cutting die on the die-holder cylinder can be inserted with its terminal spigot 9A, which has a diameter DX roughly corresponding to the diameter D, inside the portion 41 B of the slot 41A. The spigot 9A of each rod 9 is connected to a shank 9B of said rod (which terminates with a head 9C) by means of a portion 9D of said shank the diameter d of which is narrower than the diameter of the spigot 9A or of the remainder of the shank 9B. With a shaping of this type, when the rod 9 is inserted in the seat provided for this purpose in the cutting die 5 and with the spigot 9A occupying the expanded portion 41 D of the respective slot 41 A, the spigot 9A can engage with the wedge-shaped surfaces 41 D of the respective slot 41 B, so that a right-tό-left translation (in Fig. 5) of the strip 13 to which the component 41 belongs causes the wedge-shaped surfaces 41 D to co-act with the side of the spigot 9A that faces towards the head 9C of the rod . 9, with the consequent . radial displacement of the rod 9 towards the inside of the cylinder 1 and the locking in position of the cutting die 5. The component 41 of the portion 13A of the strip 13 is attached to an underlying component 43, shown separately in Figs. 13 and 14. This second component 43 comprises a plurality of second wedge-shaped surfaces 43A in the same number and positions as the slots 41A in the component 41 of the portion 13A of the strip 13. The mutual longitudinal position of the two components 41 and 43 is established by reference pins 45 (Fig.19). In the assembled arrangement (see Fig.19), the wedge-shaped surfaces 43A consequently come to be opposite the wedge-shaped surfaces 41 D. When the rod 9 is inserted with its spigot inside the slots 41A, it can be pushed radially outwards by a translational movement of the strip 13 opposite to the one previously described that induces the wedge-shaped surfaces 41 D to cooperate with the spigot 9A to induce the displacement of the rod 9 towards the insjde. of the. cylinder L .This opposite movement makes the wedge-shaped surfaces 43A co-operate with the distal side of the spigot 9A and consequently eject or push the rod 9 radially outwards to facilitate its removal from the die- holder cylinder 1.

An entirely similar configuration to the one described for the portion 13A of the strip 13 is provided for the other end portion 13B, and for the one or more intermediate portions 13C of the strips. More particularly, the components comprising the portions 13B are shown separately in Figs. 7, 8 and 9 inasmuch as concerns the outer component, and in Figs. 15 and 16 as regards the inner component of the portion 13B, while the outer and inner components of one of the intermediate portions 13C are shown respectively in Figs. 10, 11, 12, and 17, 18. The portions 13A have a recess 13X at one end that engages with a corresponding tooth 25A on the disc-shaped end element 25. Vice versa, at the opposite end, there is a recess 13Y that engages with a corresponding recess 13Z in the adjacent intermediate portion 13C. The shape of the latter mirrors the recess 13Z at the opposite end for engaging with a consecutive intermediate portion 13C, or with the recess 13Z of the end portion 13B. The latter in turn has an opposite recess 13X for engaging with a corresponding tooth 23A on the disc-shaped element 23.

With this arrangement, as shown in particular in the longitudinal portion of Fig. 3, each groove 11A on the cylindrical core 11 contains a strip 13 of any length, consisting of two portions 13A₁ 13B and a plurality of intermediate portions 13C. Said strip is anchored at its ends to the disc-shaped elements 23 and 25.

As mentioned earlier, the operation of the device according to the invention can be clearly envisaged from the above details. For further clarification, however, Figs. 32 and 33 show the way in which a single rod 9 is locked in place due to the effect of the radial displacement action exerted by a strip 13, with the consequent anchoring of the cutting die 5 to the cylinder 1.

In Fig. 32, a rod 9 has been inserted through a hole in the cutting die 5. Said rod has been inserted so that the spigot 9A extends into one of the slots 41 A on the strip 13. The spigot 9A engages with the lower wedge-shaped surface 41 D, i.e. the one facing towards the inside of the cylinder, on the strip 13._ A_. dispJaj5eirienijDf Jhe_strip 13 jn the _.direction of i the arrow f 13 (from right to left in the figure) induces the co-operation of the wedge-shaped surface 41 D with the outward-facing side of the spigot 9A on the rod 9. The wedge-shaped surface 41 D induces the displacement of the rod 9 towards the inside of the cylinder 1 , a movement that consequently makes the rod lock the cutting die 5 against the outer cylindrical surface of the cylinder 1 , defined by the surface of the battens 15. The reverse movement causes the ejection of the rod 9 due to the effect of the thrust of the wedge-shaped surface 43A against the surface of the spigot 9A that faces towards the inside of the cylinder 1.

Thanks to the provision of a large number of holes 15B on the cylindrical surface of the cylinder 1, corresponding to an equal number of slots in the strips 13 contained in the sliding seats underneath the cylindrical surface of the cylinder 1 , cutting dies of any shape and size can be locked onto the cylinder 1 by inserting an adequate number of rods 9 in the required positions. The operation for locking all the strips 13 in place simultaneously, by means of the cylinder-piston actuators 31 of the locking assembly 27, 25, 23, enables a rapid and secure locking of the cutting die in place. According to a possible embodiment, to simplify the anchoring of each cutting die to the cylinder 1 even when the rods 9 are located on the underside of the cylinder 1 during the assembly of the cutting die, in order to avoid any accidental falling of the rods 9 due to gravity before they have been locked by the translation of the strips 13, the rods 9 can be fitted with elastic retainer elements consisting, for example, of O-rings 9E, or elastic coatings 9F, as shown in Fig. 31. In said figure, the retainer elements 9E and 9F are both shown together on the two sides of the figure, but this is on the understanding that usually only either ring-shaped gaskets 9E or cylindrical coatings 9F (made of a suitable elastically flexible and compressible material) will be used. These elements induce some degree of friction between each rod 9 and the surface, for instance, of the hole 15B in the batten 15 in which the rod 9 is inserted. The slight pressure thus exerted in this way and the consequent friction prevent any accidental falling of the rods 9 from the holes 15B before the corresponding spigots 9A have engaged with and been displaced inside the cylinder 1 by the corresponding wedge-shaped surfaces 41 D. Other equivalent methods may be adopted, such as the use of laminar springs made of a metallic material instead , of rubber rings.

Clearly, the drawings merely show an example, given here as a practical illustration of the invention, which may vary in shape and layout without departing from the inventive concept. Any reference numbers used in the attached claims are merely to facilitate the reading of the claims with reference to the description and drawings, and they shall not be deemed to restrict the scope of the invention represented in the claims.

Claims

1. A die holder cylinder comprising a cylindrical shell with holes for inserting retention rods for retaining cutting dies for cutting sheet material inside said cylindrical shell, members being provided for locking said cutting die retaining rods, characterized in that said locking means comprise a plurality of strips, movable between a locking position and a releasing position, said strips being provided with elements for engaging with and displacing said rods towards the inside of the cylinder.

2. A cylinder according to claim 1 , characterized in that said strips are capable of a movement approximately parallel to the surface of said cylinder and have thrust surfaces co-operating with spigots integrally attached to said rods, the displacement of the strips parallel to the surface of the cylinder causjngjj jadlalinward and outwar4mpvemeni pf sa[d rods.

3. A cylinder according to claim 1 or 2, characterized in that said elements for engaging with and displacing the rods comprise shaped slots in which spigots of said cutting die retaining rods can be inserted, each of said slots being associated with a respective first wedge-shaped surface arranged and designed so as to displace one of said spigots towards the inside of the cylindrical shell when said strips are displaced by a cutting die-locking movement.

4. A cylinder according to claim 3, characterized in that each of said slots is associated with a second wedge-shaped surface arranged and designed to push the spigot towards the outside of the cylindrical shell when said strips are displaced with an opposite, cutting die-releasing movement.

5. A cylinder according to claim 3 or 4, characterized in that each of said slots comprises an expanded area enabling the insertion of a respective spigot and an elongated portion extending in the direction in which said strip moves, the crosswise dimension of which is narrower than the cross section of said spigot.

6. A cylinder according to one or more of the previous claims, characterized in that said strips extend in a direction substantially parallel to the axis of the cylinder. . . .

7. A cylinder according to one or more of the previous claims, characterized in that it comprises a substantially cylindrical core with a plurality of longitudinal grooves in which said strips are slidingly engaged.

81 A cylinder according to claim 7, characterized in that each of said grooves is closed by a batten that covers it, thereby defining a portion of the outer surface of said cylindrical shell, each of said battens being provided with through holes for radial insertion of said cutting die retaining rods.

9. A cylinder according to claim 8, characterized in that each of said holes in said battens coincides with a slot in a corresponding strip slidingly contained in a respective groove.

10. A cylinder according to one or more of the previous claims, characterized in that said strips are connected to driving members that control the simultaneous translational movement of said strips.

11. A cylinder according to claim 10, characterized in that said driving members comprise a first disc-shaped element around the perimeter of which first end portions of said strips are attached, said first disc-shaped element being connected to at least one actuator.

12. A cylinder according to claim 11 , characterized in that the opposite ends of said strips are attached to a second disc-shaped element.

13. A cylinder according to claim 11 or 12, characterized in that said first disc-shaped element is connected to three actuators attached to said substantially cylindrical core.

14. A cylinder according to one or more of the previous claims, characterized in that each of said strips consists of a plurality of portions connected to one another and aligned in the direction in which the strips move.

15. A cylinder according to claim 14, characterized in that the portions forming a strip are connected to one another by means of mutually engaging teeth.

16. A cylinder according to one or more of the previous claims, characterized in that said strips consist of longitudinal components that are coupled to one another so that they cannot slide in relation to one another, a first longitudinal component presenting said slots and said first wedge-shaped surfaces, a second longitudinal component presenting said second wedge- shaped surfaces.

17. A cylinder according to claim 14 and 15, characterized in that each of said portions forming a given strip consists of a pair of longitudinal components.

18. A cylinder according to one or more of the previous claims, characterized in that said rods are provided with members for temporarily retaining them on said cylinder.

19. A cylinder according to one or more of the previous claims, characterized in that said cutting die retaining rods comprise a shank, a spigot and a head, a section of said shank adjacent to said spigot being of a narrower diameter than the remainder of said shank.