Method and apparatus for machining cut-crease rules for die cutters

Abstract

A method and an apparatus are described, which allow cut-crease rules for die cutters to be obtained from creasing rules, and not assembling sections of cut rule together with sections of creasing rule. Specifically, the method comprises: (a) providing a creasing rule provided with a top edge having a continuous creasing profile, and making the rule move forward in a guide along a feed direction Y; b) temporarily stopping the rule and locking it in the guide; c) while the rule is locked in the guide, milling with a conical or circular milling cutter at least one portion of the top edge of the rule to make a cut portion preceding or following a non-machined portion of the top edge of the rule, and thus preceding or following a creasing portion; d) at the end of step c), unlocking the rule and making it move forward to carry out a new milling or to complete the machining. Thanks to the proposed solution, a cut-crease rule is obtained simply and relatively cheaply, from a single creasing rule, thus in a single body, without interruptions.

Description

[0001] Method and apparatus for machining cut-crease rules for die cutters * * *

[0002] DESCRIPTION

[0003] Field of invention

[0004] The present invention concerns the field of die cutters and specifically relates to a method and an apparatus for making cut-crease rules to be used for assembling die cutters.

[0005] State of the art

[0006] As is well known, a die cutter used in die cutting machines comprises a flat or cylindrical support, usually made of multi-layer wood, in which metal rules are mounted and provided with a cutting and / or bending edge (creasing); the rules are inserted by interference fit in corresponding slots obtained in the support and are arranged so as to reproduce the shape of a product to be made by die-cutting a paper or cardboard sheet, for example a box. The slots in the support are generally obtained by laser cutting techniques. The insertion of the rules in the corresponding slots is usually carried out manually by an operator, often with the aid of a hammer.

[0007] Raw metal rules are initially unwound and machined and bent several times to obtain the desired shapes, and finally cut to size.

[0008] Structurally, a typical die cutter rule comprises a base, which can be inserted orthogonally into the support in a corresponding slot, and an edge facing the side opposite the support, i.e., facing the sheet to be die-cut. The rules have heights extending between the base and the edge facing the sheet to be die-cut. On the die cutter support, other elements combined with the rules are provided as well, for example elastic elements commonly referred to as "rubbers", which facilitate the detachment and splitting of the die-cut portion of the sheet from the die cutter itself.

[0009] The rules are mainly subdivided into cutting rules (blades) and bending or creasing rules (creasing tools).

[0010] In the first type, the rule has a cutting edge, typically having a triangularcross section, able to cut the sheet to be die-cut when pushed to abutment against the latter and against a counter-male die cutter positioned on the opposite side of the sheet. Cutting rules are used, for example, to make the cutting lines defining the perimeter profile of a box.

[0011] The bending or creasing rules, on the other hand, have a rounded edge shaped to press, without serving, the sheet against a seat of a counter-male die placed at the opposite side with respect to the sheet to be die-cut. This way, a trace is obtained along which the bending of the sheet is easy. It is the case, for example, of the creasing lines which are on the flaps of a paper or cardboard box.

[0012] Other rules allow making the so-called weakening or tear-off lines, i.e. dashed lines which alternate cut portions with uncut portions. For example, Martin Miller firm (www.martin-miller.com) is a manufacturer of die cutter rules. Die cutter manufactures purchase the rules and machine them to obtain the blades, creasing tools and accessories needed to make the die cutter desired in each case.

[0013] In the paper processing industry, hybrid solutions are sometimes used, i.e. rules named cut-crease rules, having the edge characterized by alternating cut portions, i.e. blades, and bending portions, i.e. creasing tools.

[0014] For example, WO 2020 / 035753 describes a cut-crease rule obtained by assembling sections of cutting rule and sections of creasing rule, and a method for obtaining such a rule. Specifically, this document teaches how to make the rule by embedding sections of cutting rule and sections of creasing rule in the desired sequence, thus exploiting a dovetail coupling. The rule sections, including the respective dovetail profile or similar profile, are obtained by cutting continuous cutting rules and continuous creasing rules to size with shaped tools.

[0015] US 2018 / 178477 describes another solution for obtaining a cut-crease rule by assembling individual sections of cutting rule with individual sections of creasing rule.In general, the individual sections of the cutting rule and creasing rule must be made very accurately, with tight dimensional tolerances. Indeed, all the rule sections must be capable of being aligned with extreme precision during the assembly on the die cutter: there must be no vertical misalignment of the rule sections with respect to each other, as this would result in an inaccurate die cutter or even in an unusable cut-crease rule.

[0016] In addition, the cutting rule sections must have a perfectly straight cutting edge, and this means that at their respective ends, the cutting edges of each rule section must not be bent or damaged when shearing the rules from which the sections are obtained.

[0017] The shearing of the individual rule sections must also provide for the formation of a recess, named nick, between a cut portion and the subsequent creasing (bending) portion, so that the two portions are separated by a discontinuity in the rule edge. Document EP 2851169, in the name of the Applicant, describes a method and apparatus for making nicks by means a multiple punch.

[0018] It is desirable to simplify the manufacturing method of cut-crease rules and the related machining apparatuses as much as possible, to achieve cut-crease rules of excellent quality in shorter times and at lower costs than the solution just described which involves the assembly of individual sections of rule.

[0019] Summary of the invention

[0020] Object of the present invention is therefore to provide a method and an apparatus which allow the limits of the solutions at present available to be overcome, specifically allow excellent quality cut-crease rules, characterized by high dimensional and constructive accuracy and maximum strength, to be obtained rapidly.

[0021] A first aspect of the present invention therefore concerns a method according to claim 1 of making a cut-crease rule for die cutters from a single creasing rule, and not assembling sections of cutting rule together with sectionsof creasing rule.

[0022] Specifically, the method comprises:

[0023] (a) providing a creasing rule having a top edge having a continuous creasing profile, meaning that throughout its length the profile of the top edge is a creasing, i.e. bending, profile, and making the creasing rule, also defined rule to be machined or more simply “rule”, move forward, in a guide along a feed direction Y;

[0024] b) temporarily stopping the rule and locking it in the guide, so as to prearrange it for the following milling, so that the position of the rule does not change and the milling is accurate;

[0025] c) during step b), and thus with the rule locked in the guide, milling with a conical or circular milling cutter at least one portion of the top edge of the rule to make a cut portion preceding or following a non-machined portion of the top edge of the rule, and thus preceding or following a creasing portion;

[0026] d) at the end of step c), unlocking the rule and making it move forward to carry out a new milling or to complete the machining.

[0027] Thanks to the proposed solution, the limits of known solutions that provide for cut rule sections to be assembled with creasing rule sections are solved: the method according to the present invention allows a cut-crease rule to be obtained in a simple and relatively inexpensive way, from a single creasing rule, thus in single body, without interruptions.

[0028] Clearly, the conical or circular milling cutter can be used to make the desired number of cut portions, selectively with the desired length and the desired pitch, by alternating cut portions and creasing portions.

[0029] Preferably, in order to make each cut portion, the conical or circular milling cutter mills at the two faces of the rule, so as to form the cutting edge.

[0030] Alternatively, two conical or circular milling cutters can be used, one that exclusively machines on the upper face of the rule and the other that exclusively machines on the lower face of the rule; in this configuration, the two cutters will mill the same cut portion at different times. For example, the two conical orcircular milling cutters can be placed side by side and a first milling cutter mills the edge of the rule on the upper face, and when the rule is moved forward, the other milling cutter mills the edge of the rule on the lower face at the same cut portion.

[0031] If at least one conical milling cutter is used, each milling cutter is rotated on its own rotation axis and brought into contact with the top edge of the rule, keeping the rotation axis of the conical milling cutter perpendicular to the top edge of the rule and moving the conical milling cutter parallel to the rule along a portion corresponding to the length of the cut portion to be made. This applies to each conical milling cutter possibly used.

[0032] If at least one circular milling cutter is used, each milling cutter is rotated on its own rotation axis and brought into contact with the top edge of the rule, keeping the rotation axis of the circular milling cutter parallel to the top edge of the rule and moving the circular milling cutter along its rotation axis, parallel to the rule along a portion corresponding to the length of the cut portion to be made. This applies to each circular milling cutter possibly used.

[0033] Preferably, the method also provides a step e), implemented during step b) and before or after step c):

[0034] e) with a circular milling cutter, that can be the circular milling cutter or one of the circular milling cutters used to make the cut portion, or another circular milling cutter specifically for this purpose (named nick-making milling cutter), milling a recess, named nick, in the top edge of the rule, between a cut portion and the subsequent creasing portion.

[0035] The circular milling cutter is rotated on its rotation axis parallel to the top edge of the rule, with the milling cutter disc orthogonal to the top edge of the rule, and the circular milling cutter is moved orthogonally to the top edge of the rule to mill the nicks at the desired depth.

[0036] Optionally, a relative movement between the rule and the circular milling cutter is also provided in the feed direction of the rule to join the nick with the top edge of the rule, i.e. to make nicks that join the top edge of the rule not witha sharp corner, but with a curvature radius. The relative movement in the feed direction of the rule is achieved alternatively:

[0037] - by keeping the rule stationary and moving the circular milling cutter only, or;

[0038] - in subsequent stages, by interpolating the movement of the circular milling cutter with the movement of the rule, making the rule move forward in the guide and locking it to allow a part of the edge to be milled by the circular milling cutter at a depth that will be different in each case.

[0039] A second aspect of the present invention concerns the apparatus according to claim 10, intended for machining cut-crease rules for die cutters.

[0040] Specifically, the apparatus comprises a feeding system for feeding a creasing rule, having a guide in which the rule is moved forward with intermittent motion by appropriate means for moving forward the feeding system, and at least one first milling cutter assembly provided with at least one conical milling cutter oriented with its rotation axis orthogonal to the guide, and thus orthogonal to the top edge of the rule housed in the guide when the apparatus is in use, or provided with at least one circular milling cutter oriented with its rotation axis parallel to the guide, and thus parallel to the top edge of the rule housed in the guide when the apparatus is in use. The apparatus comprises a control unit for the described components, and the control unit comprises program means programmed for implementing the method of the present invention. In other words, the control unit is programmed to move the (either conical or circular) milling cutter towards and away from the guide, and thus towards and away from the top edge of the rule housed therein, selectively at one of the two faces of the rule. The milling cutter is also movable parallel to the guide for milling a cut portion on the top edge of the rule housed in the guide.

[0041] By controlling the movement of the milling cutter, with respect to the rule positioned in the guide, cut portions can be formed in the desired position and having the desired length.Preferably, the conical milling cutter is on three axes X, Y, Z and the rule is guided by the guide on a lying plane XY, with the top edge of the rule facing the milling cutter.

[0042] Preferably, the feeding system comprises means for moving forward the rule in the guide, which are operable intermittently, and pressure elements, for example electrical or pneumatic, mounted at the guide and operable to lock the rule in the guide in a specified position.

[0043] Preferably, the apparatus comprises at least one second milling cutter assembly provided with a circular nick-making milling cutter oriented with its rotation axis parallel to the guide, and thus parallel to the top edge of the rule housed in the guide in use. The circular milling cutter is movable towards and away from the rule to mill recesses (nicks) in the top edge of the rule that, in use, is housed in the guide and there retained by the pressure elements.

[0044] Preferably, the program control unit is programmed to move the circular nick-making milling cutter both orthogonally to the guide of the feeding system and parallel to the guide itself, by interpolating the two movements, to join the milled nick with the top edge of the rule, with a curvature radius.

[0045] The control unit is programmed for synchronizing the movement of each milling cutter assembly with the movement of the means for moving forward the feeding system and possibly for coordinating the movement of all the milling cutter assemblies the apparatus is provided with.

[0046] Brief list of the figures

[0047] Further characteristics and advantages of the invention will be more evident by the review of the following detailed description of a preferred, but not exclusive, embodiment which is depicted for illustration purposes only and without limitation, with the aid of the attached drawings, in which:

[0048] - figure 1 is an isometric view of a first apparatus for machining cut-crease rules according to the present invention;

[0049] - figure 2 is a top plan view of the apparatus shown in figure 1 ;

[0050] - figure 3 is a front and elevation partial view of the apparatus shown infigure 1 ;

[0051] - figure 4 is a perspective partial view of the apparatus shown in figure 1 during a step of implementing the method according to the present invention;

[0052] - figure 5 is a front and elevation partial view of the apparatus shown in figure 1 during a subsequent step of implementing the method according to the present invention, corresponding to the making of a cut portion;

[0053] - figure 6 is a perspective partial view of the apparatus shown in figure 1 , in a subsequent step of implementing the method according to the present invention;

[0054] - figure 7 is a front and elevation partial view of the apparatus shown in figure 1 during a subsequent step of implementing the method according to the present invention;

[0055] - figure 8 is a top plan view of the apparatus shown in figure 1 during a subsequent step of implementing the method according to the present invention, for making a recess (nick);

[0056] - figure 9 is a top plan view of the apparatus shown in figure 1 during a step of implementing the method according to the present invention;

[0057] - figure 10 is a perspective view of a cut-crease rule made with the apparatus of figure 1, operated according the method of the present invention;

[0058] - figure 11 is a schematic and perspective view of a second embodiment of an apparatus according to the present invention;

[0059] - figure 12 is a perspective view of the second embodiment of apparatus which can be used to implement the method of the present invention;

[0060] -figure 13 is a magnification of figure 12.

[0061] Detailed description of the invention

[0062] Figure 1 is an isometric view of a first embodiment of apparatus 1 according to the present invention, which can be used to implement the method of the present invention, designed for making cut-crease rules 2 from a single rule with a bending edge, i.e. a creasing rule, on which cut portions are made, as will now be explained.Figure 2 shows the same apparatus 1 in plan, from above.

[0063] The apparatus 1 is thus configured to make cut portions, alternating with bending portions (creases) on a single metal rule 2 fed to the apparatus 1 itself, avoiding the shearing and assembling of sections of two different rules, one being a cut rule and the other a creasing rule.

[0064] Figure 10 shows the cut-crease rule 2 formed by the apparatus 1, by implementing the method according to the present invention. As can be seen, the rule 2 comprises a single body 3, i.e. a body without interruptions, not obtained by joining sections previously sheared from different rules. The rule extends in height H between the top edge 4 and the lower, opposite edge. At the top edge 4 there are cut portions 5 alternating with bending portions (creases) 6, with portions 5 and 6 separated by a recess 7 named nick.

[0065] Returning to figures 1 and 2, the apparatus 1 comprises a feeding system for feeding the rule 2 to be machined, generally denoted by the reference number 8. The feeding system 8 comprises a guide 9 for the rule 2, which is configured to guide the rule on a horizontal plane containing the Y-axis along which the rule 2 moves forward, which in the figures corresponds to the length direction of the rule 2. The forward movement is caused by motorized friction wheels (not visible), i.e. provided with electric motors, which are part of the feeding system 8. The wheels engage the lower edge of the rule 2 inserted into the guide 9 and, as they rotate, push the rule along the Y-axis.

[0066] The rule 2 moves forward intermittently: the rule is stopped whenever machining is required, as it will be described hereinafter. The forward speed of the rule 2, and the distance traveled between two consecutive stops, are feedback adjusted by using friction wheel encoders conveniently controlled by a programmable control unit.

[0067] The feeding system 8 further comprises pressure elements or clamps 10, 11, for example electrically or pneumatically operated, acting to hold the rule 2 during a stop, i.e. they act to keep the rule 2 stationary and locked. A first pair of pressure elements 10 is configured to press the rule vertically (axis Z, figure 5),i.e. orthogonally to the plane in which the rule 2 moves forward; a second pair of pressure elements 11 is configured to press the rule horizontally (axis X, figure 5), i.e. parallel to the height direction H of the rule 2. The pressure elements 10 and 11 comprise respective actuators, for example pneumatic, also controlled by the programmable control unit. The synchronous actuation of the pressure elements 10 and 11 allows the position of the rule 2 to be locked for the entire duration of the actuation; clearly, by deactivating the actuators, the pressure elements 10 and 11 are pulled back to the initial condition in which they do not interact with the rule 2, which can again be moved forward by the feeding system 8 along the Y axis.

[0068] The apparatus 1 further comprises a first milling cutter assembly collectively denoted by the reference 12, and a second milling cutter assembly collectively denoted by the reference 13.

[0069] The first milling cutter assembly 12 comprises a motorized spindle 121 carrying an interchangeable conical milling cutter 122. The spindle 121 is mounted on a movable table 123 which allows controlled movements to be imparted to the spindle 121, along the Y axis, i.e. movements parallel to the length direction of the rule 2 locked in the guide 9. In turn, the table 123 is mounted on a carriage 124 which can be moved by motors 125, 126 both along the X axis, to allow the conical milling cutter 122 to move towards the rule 2 locked in the guide 9 and away from the rule 2 itself, and along the Z axis, to impart movements to the conical milling cutter 122 orthogonal to the XY plane. The orientation of the conical milling cutter 122 always remains horizontal, parallel to the XY plane.

[0070] By controlling the motors 125, 126 and the table 123, the control unit is able to bring the conical milling cutter 122 into contact with the top edge 4 of the rule 2 locked in the guide 9, and specifically to bring the milling cutter, selectively, at the upper face or the lower face of the rule 2.

[0071] The second milling cutter assembly 13 comprises an electric motor 131 that is operable, by control, to rotate a side milling cutter 132 orientedorthogonal to the rule 2, i.e. the side milling cutter 132 is kept on a ZX lying plane. The motor 132 is mounted on a movable table 133 that allows movements to be imparted along the X axis to allow the side milling cutter 132 to move towards the rule 2 locked in the guide 9 and the side milling cutter 132 to move away from the rule 2 itself. The movable table 133 is mounted on the carriage 124 that can be moved by the motors 125, 126 to allow movements of the side milling cutter 132 also along the Y and Z axes, so that, overall, the side milling cutter 132 can be moved along the three axes X, Y and Z by the control unit.

[0072] Figure 3 shows a magnification of the apparatus 1 , in a front view, during the implementation of a step of the method according to the present invention. The rule 2 is kept stationary in the guide 9 by the pressure elements 10 and 11, so as to remain perfectly aligned with the guide 9. The control unit has activated the electric motors 125, 126, 121 and the movable table 123 to move the conical milling cutter 122 towards the top edge 4 of the rule 2. Specifically, the figure shows the conical milling cutter 122 moving towards the rule 2 at its lower face, the one facing away from the pressure elements 10. In this step the side milling cutter 132 is set back on the X axis so as not to interfere with the rule 2. The top edge 4 of the rule 2 is entirely a creasing profile, meaning that the entire rule 2 is initially a creasing rule. The conical milling cutter 122 is intended for milling a portion 5 of the top edge 4 of the rule 2 to form a cut portion 5.

[0073] Figure 4 is a perspective view of the apparatus 1 at a time subsequent to the one shown in figure 3. At this step of the method according to the present invention, the conical milling cutter has already milled the top edge 4 of the rule 2, both at the lower face of the rule and at the upper face of the rule 2. The milling was performed both by rotating the conical milling cutter 122 on its rotation axis and moving the conical milling cutter 122 parallel to the rule 2, thus parallel to the feed direction Y, by moving the movable table 123 so as to span the entire length of the cut portion 5.

[0074] Clearly, since the conical milling cutter 122 is movable along the threeaxes X, Y and Z and since the movements of the conical milling cutter 122 can be synchronized by the control unit with the movements imparted to the rule 2 by the feeding system 8, the conical milling cutter 122 is able to selectively mill one or more cut portions 5, i.e. with the desired length and pitch. Figure 4 shows a single cut portion 4 but the rule 2 can be machined as shown in figure 10, to obtain cut portions 5 alternating with creasing portions 6 equidistant and of equal length, with a constant pitch, or having different lengths and different pitches.

[0075] Figure 5 is a front and elevation view showing the conical milling cutter 122 which has been brought into contact with the top edge 4 of the rule 2 while the latter is stationary in the guide 9 and locked by the pressure elements 10, 11. Specifically, the conical milling cutter 122 is resting against the rule 2 at its lower face, the one which, seeing the figure, is facing downwards. The circular milling cutter 132 is set back and does not interact with the rule 2.

[0076] Figure 6 is a perspective view showing the conical milling cutter 122 moving forward along the Y-axis. Specifically, the conical milling cutter 122 is rotated on its own axis and is simultaneously moved along the Y-axis to remove material from the top edge 4 of the rule and form the cut portion 5.

[0077] Note that figure 6 shows the conical milling cutter 122 placed under the rule 2 to machine the top edge 4 at the lower face of the rule 2, as described in relation to figure 5; however, in order to complete the cut portion 5 the conical milling cutter 122 must perform the same machining of the top edge 4 at the upper face of the rule 2 too. Figure 6 thus shows a time in which the conical milling cutter 122 has already milled the top edge 4 on the upper face of the rule 2 and is completing the milling of the top edge 4 on the lower face of the rule 2.

[0078] In other words, while the rule 2 is kept stationary in the guide 9, the conical milling cutter 122 carries out two milling operations of the top edge 4 of the rule 2: one on one face of the rule 2 and the other on the opposite face, in order to make each cut portion 5.

[0079] Milling is performed by rotating the conical milling cutter 122 on its ownrotation axis, the latter being kept orthogonal to the top edge 4 of the rule, and moving the conical milling cutter 122 along the Y axis, i.e. parallel to the rule 2, while the rule 2 is kept stationary in the guide 9. The feeding system 8 is activated to move the portion of the rule 2 to be milled in front of the conical milling cutter 122 and, at this point, the rule 2 is locked by the pressure elements 10, 11.

[0080] Figure 7 is a front and elevation view showing a step of the method according to the present invention during which the conical milling cutter 122 is inactive, for example after milling a cut portion 5, and the circular nick-making milling cutter 132 has been activated, which is moved forward to orthogonally mill the top edge 4 of the rule 2 and form the nicks 7 which separate the cut portions 5 from the creasing portions 6. Milling the nicks 7 occurs by rotating the circular nick-making milling cutter 132 and moving it orthogonally towards the rule 2 kept stationary in the guide 9 by the pressure elements 10 and 11, so as to plunge the cutting edges of the circular nick-making milling cutter 132 into the material of the rule 2.

[0081] Figure 8 is a plan view of the circular nick-making milling cutter 132 which is milling a nick 7 separating a cut portion 5 previously made by the conical milling cutter 122, and a creasing portion 6 of the top edge 4 of the rule 2.

[0082] The feeding system 8 is controlled by the control unit to impart to the rule 2 an intermittent movement synchronized with the movement of the two milling cutters 122 and 132, so that the milling cutters 122, 132 operate while the rule 2 is stationary.

[0083] Figure 9 is a magnification of figure 8 showing how the circular nickmaking milling cutter 132 can be moved to form nick 7 with a chamfered profile, not a sharp-edged corner. As indicated by the arrows in figure 9, the circular nick-making milling cutter 132 can be moved by the table 133 so as to join the nick 7 to the cut portion 5 or the adjacent creasing portion 6 at 7', alternatively to leaving the sharp edge 7".This result is achieved by the control unit, by conveniently moving the milling cutter assembly 13, by using the motors 124, 125 and the mobile table 133 or, alternatively, by interpolating two movements: the forward movement of the rule 2 in the guide 9, by the feeding system 8, and the forward movement of the circular nick-making milling cutter 132 along the X axis orthogonal to the top edge of the rule 2, proceeding by steps and locking the rule 2 with the pressure elements 10, 11 at each step.

[0084] It will be clear to the field technician that the apparatus 1 can be equipped with more than one conical milling cutter 122 and more than one circular nick-making milling cutter 132, as needed.

[0085] Figure 10, as above mentioned, shows the finished cut-crease rule 2 made with the apparatus 1 and according to the method of the present invention, from a single piece rule 2. The milling cutters 122 and 132 made the alternated cut portions 5 and creasing portions 6 arranged in succession and separated by the nicks 7.

[0086] Figure 11 is a simplified perspective view of a second embodiment T of an apparatus according to the present invention, which can be used to implement the method according to the present invention. The apparatus T has the same characteristics as the apparatus 1 (first embodiment) except that, the apparatus T uses at least one circular milling cutter 140 to make the cut portions 5, in replacement of the at least one conical milling cutter 122.

[0087] The at least one circular milling cutter 140 is oriented with the rotation axis R parallel to the rule 2, so that the cutting edges 141 of the milling cutter 140 can remove material from the top edge 4 of the rule 2.

[0088] Figure 12 is a perspective view of the overall apparatus T configured to make cut portions, alternating with bending sections (creases) on a single metal rule 2 fed to the apparatus T itself, avoiding the shearing and assembling of sections of two different rules, a cut rule and a creasing one, as shown in figure 10.

[0089] Figure 13 is a magnification of figure 12.In reference to both figures 12 and 13, the apparatus T, like the apparatus 1, also comprises a feeding system for feeding the rule 2 to be machined, generally denoted by the reference number 8. The feeding system 8 comprises a guide 9 for the rule 2, which is configured to guide the rule on a horizontal plane containing the Y-axis along which the rule 2 moves forward, which in the figures corresponds to the length direction of the rule 2. The forward movement is caused by motorized friction wheels (not visible), i.e. provided with electric motors, which are part of the feeding system 8. The wheels engage the lower edge of the rule 2 inserted into the guide 9 and, as they rotate, push the rule along the Y-axis.

[0090] In this case, too, the movement forwards of the rule 2 is intermittent: the rule is stopped whenever machining needs to be performed, as will be described below. The forward speed of the rule 2, and the distance traveled between two consecutive stops, are feedback adjusted by using friction wheel encoders conveniently controlled by a programmable control unit.

[0091] Like in the apparatus 1 , the feeding system 8 further comprises pressure elements or clamps, for example electrically or pneumatically operated, acting to retain the rule 2 during a stop, i.e. acting to keep the rule 2 stationary and locked. The synchronous actuation of the pressure elements allows the position of the rule 2 to be locked for the entire duration of the actuation; clearly, by deactivating the actuators, the pressure elements are returned to the initial condition in which they do not interact with the rule 2, which can again be moved forward by the feeding system 8 along the Y axis.

[0092] The apparatus T also comprises a first milling cutter assembly generally denoted by the reference 14, and optionally the second milling cutter assembly denoted by the reference 13 in the apparatus 1 and not visible in the apparatus T (but that can be mounted on the same).

[0093] The first milling cutter assembly 14 comprises at least one circular milling cutter 140, as described in figure 11, and preferably also a second circular milling cutter 150 coplanar with the first circular milling cutter 140. These millingcutters are interchangeable on their respective spindles. The first milling cutter assembly 14 is movable on the YZ plane and on the XZ plane (reference system shown in figure 11) to bring the circular milling cutter to machine the rule 2 in order to make the cut portions 5, as described in relation to the conical milling cutter 122.

[0094] By using two milling cutters 140 and 150 two cut portions 5, or a single cut portion 5 at its top and bottom edges, selectively, can be machined simultaneously.

[0095] The operation of the apparatus T is the same as the operation of the apparatus 1, except that the milling cutter, or the milling cutters, used 140, 150 is / are circular and not conical. Milling a cut portion 5 is performed by both rotating the circular milling cutter 140 on its rotation axis R and moving the circular milling cutter 140 parallel to the rule 2, thus parallel to the feed direction Y, by moving the milling cutter assembly 14 so as to span the entire length of the cut portion 5.

Claims

1. CLAIMS1. A method of making a cut-crease rule (2) for die cutters from a single creasing rule, comprising:(a) providing a creasing rule provided with a top edge (4) having creasing profile, and make it move forward in a guide (9) along a feed direction (Y);b) temporarily stopping the rule (2) and locking it in the guide (9);c) during step b), milling with a conical milling cutter (122) or a circular milling cutter (140) at least one portion of the top edge (4) of the rule (2) to make a cut portion (5);d) at the end of step c), unlocking the rule (2) and making it move forward.

2. Method according to claim 1 , wherein the portions milled by the conical milling cutter (122) or the circular milling cutter (140) are cut portions (5) and the not-milled portions are creasing portions (6).

3. Method according to claim 1 or claim 2, wherein step c) is carried out: by milling the top edge (4) of the rule both at the upper face of the rule, and at the lower face of the rule.

4. Method according to any one of the preceding claims, wherein step c) is carried out,by rotating the conical milling cutter (122) on its own rotation axis, keeping the rotation axis of the conical milling cutter (122) orthogonal to the top edge (4) of the rule and moving the conical milling cutter (122) parallel to the rule (2) along a portion corresponding to the length of the cut portion (5) to be made, or alternativelyby rotating the circular milling cutter (140) on its own rotation axis (R), keeping the rotation axis (R) of the circular milling cutter (140) parallel to the top edge (4) of the rule and moving the circular milling cutter (140) along its rotation axis (R) and parallel to the rule (2) along a portion corresponding to the length of the cut portion (5) to be made.

5. Method according to any one of the preceding claims, comprising,during step b) and prior or after step c):e) milling, with a circular nick-making milling cutter (132), a recess named nick, between a cut portion (5) and the subsequent creasing portion (6).

6. Method according to claim 5, wherein the circular nick-making milling cutter (132) is rotated on its own rotation axis parallel to the top edge (4) of the rule, with the circular milling cutter (132) orthogonal to the top edge (4) of the rule, and the circular milling cutter (122) is moved orthogonally to the top edge (4) of the rule.

7. Method according to claim 6, wherein a relative movement between the rule and the circular nick-making milling cutter (132) is provided in the feed direction of the rule to join a nick (7) with the top edge (4) of the rule.

8. Method according to claim 7, wherein the relative movement in the feed direction of the rule is achieved alternatively:- by keeping the rule stationary and moving the circular nick-making milling cutter (132) only, or;- in subsequent stages, by interpolating the movement of the circular nick-making milling cutter (132) with the movement of the rule, making the rule move forward in the guide (9) and locking it to allow a part of the edge (4) to be milled by the circular milling cutter (132).

9. Method according to any one of the preceding claims, wherein the cut-crease rule (2) is formed by milling portions (5) of the top edge (4) of a single creasing rule and not assembling sections of creasing rules and cutting rules.

10. An apparatus for machining cut-crease rules (1) for die cutters, comprising a feeding system (8) for feeding a creasing rule, with a guide (9) in which a rule to be machined (2) is moved forward with intermittent motion, and at least one first milling cutter assembly (12) provided with a conical milling cutter (122) oriented with its rotation axis orthogonal to the guide (9), and thus orthogonal to the top edge (4) of the rule housed in the guide (9) in use, or with a circular milling cutter (140) oriented with its rotation axis parallel to the guide (9), and thus parallel to the top edge (4) of the rule housed in the guide (9) inuse,and comprising a control unit of the feeding system (8), of the conical milling cutter (122) or the circular milling cutter (140), wherein the control unit is provided with program means programmed for:a) making the rule to be machined (2) move forward in the guide (9) along a feeding direction (Y);b) temporarily stopping the rule to be machined (2) and locking it in the guide (9);c) during step b), milling with the conical milling cutter (122) or the circular milling cutter (140) at least one portion of the top edge (4) of the rule (2) to make a cut portion (5);d) at the end of step c), unlocking the rule (2) and making it move forward.

11. Apparatus according to claim 10, wherein the conical milling cutter (122) or the circular milling cutter (140) are movable along three axes X, Y, Z and the rule to be machined (2) is guided by the guide (9) on a lying plane XY, with the top edge (4) of the rule to be machined (2) facing the conical milling cutter (122) or the circular milling cutter (140).

12. Apparatus according to claim 10 or claim 11, wherein the feeding system (8) comprises means for moving forward the rule to be machined (2) in the guide (9) and pressure elements (10, 11) mounted at the guide (9) and operable to lock the rule to be machined (2) in the guide (9).

13. Apparatus according to any one of preceding claims 10-12, comprising at least one second milling cutter assembly (13) provided with a circular nick-making milling cutter (132) oriented with its rotation axis parallel to the guide (9), and thus parallel to the top edge (4) of the rule housed in the guide (9) in use, and wherein the circular nick-making milling cutter (132) is movable towards and away from the rule to mill recesses, named nicks, in the top edge (4) of the rule.

14. Apparatus according to claim 13, wherein the control unit isprogrammed to move the circular nick-making milling cutter (132) both orthogonally to the guide (9) of the feeding system (8) and parallel to the guide (9) itself, by interpolating the two movements to join the milled nick with the top edge (4) of the rule to be machined (2).

15. Apparatus according to any one of preceding claims 10-15, comprising a program control unit programmed to move at least one milling cutter assembly (12, 13) while milling on the top edge (4) of the rule to be machined (2), while the rule to be machined (2) is kept stationary in the guide (9) of the feeding system (8).

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