Patent Description:
The known die-cutting systems are configured to perform a die-cutting process comprising the use of the following elements:.

Focusing for simplicity on a standard cardboard box <NUM> (<FIG>), it is a very common model manufactured in several sizes. As seen from the figure, the box height "h" and the size of panels <NUM>-<NUM> (a panel means a zone delimited by folds or creases <NUM>, dashed in the figure; all other edges <NUM> are obtained by cutting or pre-cutting) can be any (the size of panels <NUM>-<NUM> is usually the same as that of panels <NUM>-<NUM>). Reference numeral <NUM> indicates the flaps of the box.

In the prior art, a whole cutting die is normally manufactured which is suitable for a specific model having a specific size (<FIG>). If the model or the size change, there is a need to manufacture a new cutting die. In the cutting die <NUM> of <FIG>, cutting and folding elements <NUM> and feeding elements <NUM> can be seen. Such elements are fixed to curved supports <NUM> fixed to an underlying cylinder (not shown) by means of fixing elements, such as screws.

Sometimes, again in the prior art, the packaging production only relates to very large standard cardboard boxes, and to manufacture them there is a need to halve the width thereof thus having only half of a box (<FIG>, parts <NUM> and <NUM> only, "half standard cardboard box") and then glue the two halves together to obtain the whole box of the desired width. In this case, the standard cutting die will be as shown in <FIG>, manufactured in a single piece given a drawing with specific size only valid for a particular packaging to be produced (<FIG>).

As a result, with standard cutting dies, a new cutting die should be prepared whenever the size of the same box model changes. This new cutting die will also be valid only for the size of that specific box model.

The need is felt not to have to manufacture a whole cutting die for each specific packaging to be produced.

It is an object of the present invention to provide a modular system and a method for assembling a packaging cutting die which solves the problems and overcomes the drawbacks of the prior art.

The present invention relates to a modular system and a method for assembling a packaging cutting die according to the appended claims.

The invention will now be described by way of nonlimiting illustration, with particular reference to the figures of the accompanying drawings, in which:.

It is specified herein that elements of different embodiments can be combined together to provide further embodiments without restrictions by respecting the technical concept of the invention, as an ordinary skilled person will effortlessly understand from the description.

Moreover, the present description also refers to the prior art for the implementation thereof, regarding the detail features not described, such as elements of minor importance usually used in the prior art in solutions of the same type, for example.

When an element is introduced, it is always understood that there can be "at least one" or "one or more".

When a list of elements or features is given in this description, it is understood that the finding according to the invention "comprises" or alternatively "consists of" such elements.

Two or more of the parts (elements, devices, systems) described below can be freely associated and considered as part kits according to the invention.

Referring to the example of known box in <FIG>, in the case of an embodiment of the magnetic modular cutting die according to the invention, the same box will be manufactured instead by assembling magnetic parts already arranged on the metal cylinder.

The modular assembly elements are shown, according to an embodiment, in <FIG>. In this embodiment, the set <NUM> of modular elements <NUM> is a set of elements of the same shape but different size.

The shape of the single element <NUM> is substantially rectangular, with a curvature in the direction perpendicular to the sheet. More generally, the single module <NUM> has a perimeter comprising two first opposite sides transverse to said extension direction and two second opposite sides parallel to an extension direction.

In more detail, each element <NUM> has two ends (or in general first end sides) along a main direction (vertical in the drawing, this is an extension direction along an arc of a circle). At one end, each element has a recess <NUM> and at the other end a tooth <NUM> (or first shape coupling means positioned on one of said first end sides) sized to enter into the notch or recess <NUM> (corresponding second shape coupling means positioned on an opposite side of said first end sides), so as to cover an arc of a circle on the metal cylinder. Indeed, one of the two surfaces of each element (surfaces in the direction perpendicular to the main direction) is magnetic and is intended to adhere to the metal cylinder (having an axial direction perpendicular to said extension direction). Here, the magnetic surface is also referred to as a "connection surface", included in said perimeter. The surface opposite to the connection surface is the so-called "die surface", comprising the elements described below.

In detail, the tooth <NUM> (e.g., central on the side from which it protrudes) is obtained by eliminating the corners <NUM> of the rectangle, and the notch or recess <NUM> constructionally has side protrusions <NUM>. There can also be multiple teeth and multiple recesses, in any embodiment, e.g., two teeth and two recesses, in particular at the ends of the sides perpendicular to said extension direction.

In all embodiments, the cutting die modules can have a different length in said extension direction along an arc of a circle.

<FIG> shows the association of two elements like those just described: in (a) they are just spaced apart, while in (b) the two elements are joined (thus achieving shape coupling by said first and second shape coupling means). The above-mentioned curvature is observed. The element <NUM> is one of the cutting/folding/feeding elements mentioned above with reference to <FIG>. The element <NUM> is specifically a folding element, shown as an example.

<FIG> shows a partial assembly of a cutting die according to the invention. Here, the modules <NUM> are slightly different in that the recess <NUM> and the tooth <NUM> are much narrower, but the concept is similar. Moreover, according to the invention, other shapes dedicated to the coupling of various modules are possible. Two similar strips are assembled on the cylinder <NUM> in the figure. The elements <NUM> are cutting elements appropriately fixed on the modules (they can be considered part of the modules).

<FIG> shows four strips assembled on the cylinder <NUM>, with cutting elements <NUM> on some of the modules <NUM> and feeding elements <NUM>. The cylinder <NUM> is perforated but it is not a necessary condition, precisely because the magnetic coupling makes screw means unnecessary for fixing the cutting die elements. In general, and for all embodiments, each cutting die module has "cutting die elements" that can be cutting and/or feeding and/or folding elements. A subset of the cutting die elements can also comprise only one type of the mentioned elements, in particular only feeding elements.

Advantageously according to the invention, the magnets of the modules have an adequate magnetic force to withstand the stresses generated during the use of the cutting die. Each module must withstand the stresses and remain in the assigned position. Below is a table with exemplary intervals:.

It is apparent that a high magnetic force makes it difficult to detach the module for assembling a new cutting die. For this purpose, on the edge of each module (or on a portion of the edge), a few millimeters (e.g., <NUM>-<NUM>) of material are removed from the side of adhesion to the metal cylinder so as to fit an appropriate lever into this void between the module and the metal cylinder.

An example of this lever is given in <FIG>, diagrammatically showing (a) a top view of the module <NUM> above, with the tooth <NUM> and the cutting blade <NUM>, and (b) a bottom view of the same module <NUM>, where the partially peripheral empty space <NUM> is highlighted, while the module magnet <NUM> is in the middle (in general and for all embodiments, it extends over at least one portion from the connection surface). The space <NUM> can be partially peripheral or even totally peripheral, i.e., it can run all around the magnet <NUM>, which for convenience is shown square in shape, but can have other shapes. In the space or region <NUM>, the thickness of the cutting die module in the direction perpendicular to the extension direction is preferably less than the thickness of the cutting die module where said module magnet <NUM> is present.

The module magnet <NUM> is chosen with a magnetization constant such that it applies a nominal attraction force between <NUM> and <NUM>/cm<NUM>, more preferably between <NUM> and <NUM>/cm2, so that it can withstand the cylinder rotation even better.

The distance d is the distance between the edge of the module <NUM> and the beginning of the magnet, on one or more sides where the magnet is not flush with such an edge. One of the two angled ends <NUM> and <NUM> of the lever <NUM> shown in figure (c), precisely configured to insert and lift the cutting die module with respect to the metal cylinder, is fitted into space <NUM>. Preferably, the lever <NUM> (shown in the figure without thickness for simplicity) comprises a central body <NUM>, with respect to which the end <NUM> forms an angle β and the end <NUM> forms an angle α. Preferably, at least one of the two angles is between <NUM>° and <NUM>°, even more preferably of about <NUM>°, which angles ensure high practicality of use.

Below are some composition examples of cutting dies that can be made by means of the modular system of the invention:.

With reference to <FIG>, an off-machine assembly system for magnetic modular cutting dies is described.

The system is developed about a concept of off-machine arrangement of the axial extension size required for the box.

Once the axial size has been set up on a supplied millimeter bar <NUM> made of aluminum or other material (in this application "millimeter bar" means any graduated scale extending in a linear direction, for example, and allows measuring a distance), the bar <NUM> itself is placed in the machine with a magnetic coupling (by means of a "bar magnet", not shown), and the modular cutting die is composed by means of the magnetic coupling system.

For example, the cutting die is configured with:.

The concept is the off-machine arrangement (axial size) and quick assembly system of the magnetic modular cutting die.

In general, the graduated bar comprises:.

As shown, one slider <NUM> for each module strip can slide in the linear guide <NUM>. The slider <NUM> has fixing means <NUM> allowing the slider itself to be clamped at a given height of the guide <NUM>. After the off-machine arrangement, the bar (with millimeter scale <NUM>) is thus placed at the metal cylinder <NUM> and the modules <NUM> are adhered to the cylinder. The sliders <NUM> are then disengaged and the bar removed.

Note that the slider <NUM> has a recess <NUM> for the connection with the cutting die modules <NUM> (or <NUM> in the embodiment described above). There can be a protrusion or tooth instead of the recess, the cutting die modules being capable of being positioned with a corresponding recess; any shape coupling is possible between slider and modules and between module and module, according to the invention.

As with the cutting die modules, the graduated bar <NUM> can also have a magnet-free region along at least one portion of the perimeter thereof, for the insertion of a lever dedicated to removing the graduated bar itself.

Similar to the cutting die modules, the bar magnet can be chosen with a magnetization constant such that it applies a nominal attraction force between <NUM> and <NUM>/cm<NUM>, preferably between <NUM> and <NUM>/cm<NUM> so as to ensure an adequate adhesion against external stresses.

As seen from the figures, by virtue of the system of the invention (step A) it is possible to manufacture a cutting die by arranging one or more cutting die modules <NUM>; <NUM> on said metal cylinder <NUM> with the corresponding module magnet <NUM> in contact with the metal cylinder <NUM>.

Such an arrangement step B can comprise the following sub-steps:.

Moreover, step B can comprise the following preliminary step:
B0. removing, by means of the aforesaid lever, at least one cutting die module <NUM>; <NUM> previously magnetically fixed to said metal cylinder <NUM>.

The system according to the invention is advantageous for various box models. For each box model, the system is universal, i.e., it becomes a durable good, no longer manufactured for a specific order.

The manufacturer of a box, with the modular system according to the invention, does not need to order a special cutting die but already has the system in-house to manufacture it.

This results in a significant improvement for the user such as:.

Claim 1:
A modular system for creating a cutting die, comprising:
- a set of cutting die modules (<NUM>, <NUM>), each cutting die module having:
▪ an extension direction along an arc of a circle;
▪ a perimeter comprising two first opposite sides transverse to said extension direction and two second opposite sides parallel to said extension direction;
▪ a connection surface included in said perimeter, the connection surface being configured to be positioned on a metal cylinder (<NUM>) extending in an axial direction, with said extension direction perpendicular to said axial direction;
▪ a die surface included within said perimeter and opposite to said connection surface, said die surface comprising at least one die or feeding element (<NUM>,<NUM>,<NUM>; <NUM>,<NUM>,<NUM>);
the system being characterized in that:
- said connection surface comprises a module magnet (<NUM>) extending over at least one portion from the connection surface;
- each cutting die module comprises first shape coupling means (<NUM>; <NUM>) on one of said first sides and corresponding second shape coupling means (<NUM>; <NUM>) on the other of said first sides, so that two different modules (<NUM>; <NUM>) can achieve shape coupling by said first and second shape coupling means.