EP2777899A1

EP2777899A1 - Machine for working cardboard slabs

Info

Publication number: EP2777899A1
Application number: EP14158469.8A
Authority: EP
Inventors: Remo Lorenzoni
Original assignee: Lcr Macchine Automatiche Srl
Current assignee: Lcr Macchine Automatiche Srl
Priority date: 2013-03-13
Filing date: 2014-03-10
Publication date: 2014-09-17
Also published as: ITBO20130108A1

Abstract

A machine for working cardboard or the like, comprising a frame (2) forming a supporting surface (A) of a cardboard slab (100), feed means (3) of the cardboard slab (100) on the supporting surface (A) along a rectilinear movement direction (B) and at least a first (5) and a second cutting unit (6) equipped with one or more cutting blades (5a, 6a) oriented respectively parallel and transversally to the direction of movement (A). The machine also comprises at least one carriage (13) movable transversely to the direction of movement (B) along a relative operating direction (C) and equipped with at least one creasing tool (14), designed for making crease lines on the slab of cardboard (100), and at least one slitting tool (15), designed for making slots (101) of predetermined length in the slab of cardboard (100), both oriented parallel to the operating direction (C).

Description

This invention relates to a machine for working cardboard slabs or the like. This invention is applicable in particular to the making of blanks for forming cardboard boxes.
In the industry of the working of cardboard or the like there are prior art machines for making blanks made of cardboard or the like, which are then folded and formed so as to obtain boxes for packaging.
The purpose of these machines is to make cuts, creases or slits (that is, slots) on slabs or sheets of cardboard prepared inside the machine.
In this description, the machine is described with reference to the working of cardboard or the like, thereby meaning any material made of slabs or sheets, either in a continuous form or in rolls, even plastic materials, such as, for example, honeycomb polypropylene, or wood.
Currently, there are so-called "casemaker" machines equipped with a frame to which are associated means for feeding a slab of cardboard and a plurality of cutting, creasing and slitting heads, configured to perform the respective processing operations during sliding of the cardboard.
The above-mentioned machines comprise two cutting elements, one longitudinal, that is, parallel to the direction of feed of the cardboard, and one transversal, that is, at right angles to the direction of feed of the cardboard.
Similarly, there can be the same number of creasing heads, which are, however, preferably oriented in a single direction.
With regard to the slitting tools, the prior art proposes two solutions which are alternative to each other.
A first prior art solution, the so-called "guillotine", involves the use of slitting means defined by fixed blades, oriented longitudinally or transversally, moved rhythmically towards and away from the cardboard to make the slots. The blades are located in a predetermined position during set up of the machine and are moved by suitable mechanical actuators for making fast sequences of blanks.
Disadvantageously, although considerably fast and high-performing, these systems are very rigid and are only economically advantageous in the production of large batches.
In effect, the set up step of the machine is too lengthy and to all intents not remunerative to make small batches, or even individual pieces.
The second prior art solution involves the use of longitudinal rotating blades, that is to say, oriented parallel to the direction of movement, which are capable of making the incisions (that is, the slots) during the movement of the cardboard, that is, continuously, exploiting the movement of the means for feeding the cardboard.
Disadvantageously, in these configurations it is necessary to provide a number of slitting units equal to the maximum quantity of slits which can be expected for a certain type of box.
Thus, whilst being particularly versatile, slitting units such as those just described are very expensive and complicated to make. Moreover, it should noted that if the cardboard needs a greater number of slits, the machine would be unusable for that format, thus considerably limiting the freedom and flexibility of the manufacturer.
The aim of this invention is to provide a machine for working cardboard slabs or the like which overcomes the above-mentioned drawbacks of the prior art.
More specifically, the aim of this invention is to provide a machine for working cardboard slabs or the like which is extremely versatile and relatively inexpensive.
Moreover, the aim of this invention is to obtain a machine for working cardboard slabs or the like which is able to make a wide range of cuts, creases and slits in an extremely precise fashion and with limited set up times.
These aims are achieved by a machine for working cardboard slabs or the like having the features described in one or more of the subsequent claims.
More specifically, these aims are achieved by a machine for working cardboard slabs or the like, comprising a frame forming a supporting surface of a cardboard slab, feed means of the cardboard slab on the supporting surface along a rectilinear movement direction, at least a first cutting unit equipped with one or more cutting blades oriented parallel to the direction of movement and at least a second cutting unit equipped with one or more cutting blades oriented transversally to the direction of movement.
According to this invention, the machine comprises at least one carriage movable transversely to the direction of movement along a relative operating direction and equipped with at least one creasing tool, designed for making crease lines on the slab of cardboard, and at least one slitting tool, designed for making slots of predetermined length on the slab of cardboard, both oriented parallel to the operating direction.
Advantageously, the presence of a single carriage movable transversely to the direction of movement (i.e. feed direction) of the cardboard equipped with both the creasing device and the slitting device allows a machine to be obtained which is extremely economical and able to make a wide range of blanks by simply varying the position of the carriage (by translating it) and controlling the drive of the tools.
Further features and advantages of this invention are more apparent in the detailed description below, with reference to a preferred, non-limiting embodiment of a machine for working cardboard slabs or the like, as illustrated in the accompanying drawings, in which:

Figure 1 is a schematic side cross section view of the machine for working cardboard slabs or the like according to this invention, with some parts cut away in order to better illustrate others;
Figure 2 shows an enlargement of the detail "R" of Figure 1;
Figure 3 is a front view of a portion of the machine of Figure 1;
Figure 4 shows an enlargement of the detail "P" of Figure 3;
Figures 5a to 5e show a working sequence of a slitting tool of the machine of Figure 1;
Figures 6a to 6c show schematic plan views of a sequence of operational steps of the machine of Figure 1 during use;

With reference to the accompanying drawings, the numeral 1 denotes a machine for working cardboard slabs or the like according to this invention.
The machine 1 is of the type commonly called "casemaker" configured to make, from slabs of corrugated cardboard, blanks provided with fold lines (or creases), slits (slots) and flippers (closed flaps) designed to allow the formation of a box (for example of the American type).
The machine 1 comprises a frame 2 equipped with a supporting portion 2a, or base, and defining a surface "A" for supporting a cardboard slab 100.
Means 3 for feeding the slab of cardboard 100 on the supporting surface "A" along a rectilinear direction of movement "B" are also associated with the frame 2.
The feed means 3 operate between the frame 2 and the slab 100 to move it from a loading portion 2b of the frame 2 to an unloading portion 2c, passing through a machining portion 2d to which the processing means (cutting, slitting, creasing etc.) of the machine 1 are associated.
In the embodiment illustrated, the loading zone 2a of the slab 100 is defined by a platform 4 projecting in front of the frame 2. The feed means 3 comprise a conveyor belt or conveyor, or a plurality of rollers adjacent to each other and made/coated with a material such as to increase the friction.
However, in alternative embodiments, the loading zone could be equipped with an automatic loader or a storage system, or even a reel unwinder roller (in applications in which the material to be processed is wound on a roll).
As already indicated, the processing portion 2d of the frame 2 is associated with the processing, or operational, means of the machine 1.
More specifically, the machine 1 comprises at least a first 5 and a second 6 cutting unit equipped with one or more cutting blades 5a, 6a.
The cutting blades 5a of the first unit 5 are oriented parallel to the direction of movement "B", thus being "longitudinal" cutting blades.
The cutting blades 6a of the second unit 6 are oriented parallel to the direction of movement "B", thus being "transversal" cutting blades.
It should be noted that, in this text, to define the orientation of the blades 5a, 6a reference is made to the edge, that is, the cutting part of the blades 5a, 6a.
Thus, the edge of the blade (or blades) 5a of the first unit 5 is oriented parallel to the direction of movement "B", whilst the edge of the blade (or blades) 6a of the second unit 6 is oriented transversally (preferably at right angles) to the direction of movement "B".
Preferably, the blades 5a, 6a of the cutting units 5, 6 are defined by disks rotatable relative to a support 7, 8 about respective axes of rotation.
The axis of rotation of the cutting disk of the first unit 5 is at a right angles to the direction of movement "B"; the axis of rotation of the cutting disk of the second supporting unit 6 is parallel to the direction of movement "B".
Preferably, the supports 7, 8 comprise a carriage 9, 10 movable transversally to the direction of movement "B" which are associated with movement means 11, 12, preferably pneumatic, designed for moving the blades 5a, 6a (that is, the disks 7a, 8a) towards and away from the supporting surface "A" depending on the processing which must be performed (and/or of their active/passive condition).
It should be noted that the disks are moved by actuator unit X configured to impart to the peripheral portion of the blade 5a, 6a a peripheral speed substantially equal (that is, corresponding) to a speed of translation (transversal) of the carriage 12 (in the case of the second unit 6) or a feed speed (longitudinal) of the cardboard slab 100 (in the case of the first unit 5). Advantageously, this increases the efficiency of the cutting.
According to this invention, the machine 1 also comprises at least one carriage 13 movable transversely to the direction of movement "B" along a relative operating direction "C"; the carriage 13 is equipped with at least one creasing tool 14, designed for making crease lines on the slab of cardboard 100, and at least one slitting tool 15, designed for making slots 101 of predetermined length in the slab of cardboard 100.
The creasing tool 14 is an element configured to make a dry mark 103 (or channel) on the slab of cardboard 100 such as to facilitate folding in the box forming step.
The slitting tool 15 is an element shaped to create a slot 101 or separating gap between two adjacent tabs (or flaps) of the slab 100 to avoid interference between them in the box forming step.
Both the creasing tool 14 and slitting tool 15 have an active portion which is oriented parallel to the operating direction "C", that is, at right angles to the direction of movement "B".
Thus, the carriage 13 defines a processing unit which is transversal (more specifically at right angles) to the direction of movement "B".
It should be noted that the second cutting unit 6 and the carriage 13, both movable transversally to the direction of movement "B", are movable independently along the operating direction "C".
Thus, the carriage of the second unit 6 and the carriage 13 each have relative actuator means 16 controlled independently by a control unit 27 to determine the positioning of the cutting blades 6a and of the creasing tools 14 and slitting tools 15 depending on the type of processing set up.
Preferably, the second cutting unit 6 (more specifically the carriage 10) and the carriage 13 are associated with respective crosspieces 17a, 17b extending along the operating direction "C" and arranged one after another along the direction of movement "B".
In the embodiment illustrated, the second unit 6 and its crosspiece 17a are positioned in a position proximal to the loading zone 2a relative to the carriage 13 and to its crosspiece 17b.
Thus, the crosspieces 17a, 17b extend along the operating direction "C" and are slidably coupled, respectively, to the carriage 10 of the second unit 6 and to a main body 13a of the carriage 13.
It should be noted that, preferably, the first cutting unit 5 is also associated with a respective crosspiece 17c similar to that just described.
Thus, the carriage 13 is slidably associated with the respective crosspiece 17a, which acts a guide for it.
Preferably, the creasing tool 14 comprises at least one disc-shaped element rotatable relative to the carriage 13 about an axis of rotation substantially parallel to the direction of movement B.
Similarly, the slitting tool 15 also comprises at least one disc-shaped element rotatable relative to the carriage 13 about an axis of rotation substantially parallel to the direction of movement B.
Thus, the axis of rotation of the disc-shaped element of the creasing tool 14 is parallel to the axis of rotation of the disc-shaped element of the slitting tool 15.
More specifically, the creasing tools 14 and/or the slitting tools 15 have a central core 14a, 15a and a peripheral portion 14b, 15b shaped for making the crease and/or the slot (or gap) 101.
The peripheral portion 14b of the creasing tool 14 is equipped with an annular protrusion 14c designed to make the groove (crease) in the cardboard.
It should be noted that the actuator means 16 of the carriage 13 are designed for moving the creasing tools 14 and/or the slitting tools 15 in roto-translation along the operating direction "C".
More specifically, the actuator means 16 are designed for imparting to the peripheral portion 14b of the creasing tool 14 a peripheral speed substantially corresponding to the translation speed of the carriage 13.
In this regard, the actuator means 16 comprise a motor 16a operatively interposed between the main body 13a of the carriage 13 and the respective crosspiece 17b to translate the carriage 13 along it.
In the preferred embodiment, the motor 16a is of the electrical type and is connected to the main body 13a of the carriage 13 by a belt 16b.
Moreover, there are drive means 18 operatively interposed between the main body 13a of the carriage 13 and the creasing tool 14 to rotate its as a function of the movement of the main body 13a.
Thus, the drive means 18 are designed for imparting to the creasing tool 14 an angular speed (that is, rotational speed) proportional to the translation speed of the carriage 13 to which they are rotatably associated. The drive means 18 may be either mechanical or electronic, the latter equipped with sensors and drives.
In the preferred embodiment, the drive means 18 comprise a rack 18a rigidly connected to the crosspiece 17b and at least one gear (not illustrated) interposed between the rack 18a and the creasing tool 14 for rotating it.
The gear may be defined by a plurality of gear wheels or by a single gear wheel rigidly connected to the respective creasing tool 14 and engageable from the rack 18a.
Advantageously, in this way the motion transmitted to the creasing tool 14 is precise, simple and inexpensive to achieve.
It should be noted that, in an alternative embodiment, the creasing tool 14 is pivoted to the carriage 13 and able to rotate freely relative to it (that is, idle).
In that case, the rotation of the creasing tool 14 is imparted by friction with the slab 100 during translation of the carriage 13.
In the preferred embodiment, the actuator means 16 comprise a further motor 26 (or gear motor) coupled to the slitting tool 15 to rotate it independently from the movement of the carriage 13.
Preferably, the actuator means 16 are associated with a control unit 27 configured for putting in relation the speed of rotation of the slitting tool 15 with the speed of translation of the carriage 13. This relation is achieved by an electronic interpolation so as to define the angular position of the slitting tool 15 in such a way as to determine the correct length of the slit (or slot 101).
Preferably, the carriage 13 also comprises a pressing tool 19 designed for acting on a predetermined portion of the slab of cardboard 100 for reducing the thickness.
The pressing tool 19, in the jargon of the trade known as "flipper flattener" is particularly useful in machines for processing cardboard with a thickness greater than 2 mm, in which it is necessary to flatten the ends of the two flaps of cardboard which are superposed in the closing of a box of the "American" type.
In the embodiment illustrated, the pressing tool 19 comprises a disc 19a having a peripheral annular crown 19b rotatable relative to the main body 13a of the carriage 13. The pressing tool 19 is thus able to rotate (freely or guided) about its own axis of rotation parallel to the direction of movement "B".
Preferably, the peripheral annular crown 19b has a thickness, calculated parallel to the axis of rotation, greater than 15 mm, in such a way as to guarantee a balanced flattening of the cardboard flap.
In the preferred embodiment, the pressing tool 19 is also moved (in roto-translation) by the above-mentioned drive means 16, and in particular by the motor 16a and the drive means 18 (preferably the same rack 18a).
Alternatively, the pressing tool 19 can also be pivoted to the carriage 13 in an idle fashion, in the same way as described for the creasing tool 14.
In its preferred embodiment, the slitting tool 15 has a peripheral portion 15b defined by a curved blade 20 extending around the central core 15a between a first 21 and a second tip 22.
The curved blade 20 has an angular extension less than 360°, preferably between 100° and 320°, in such a way that the first tip 21 and the second tip 22 are spaced from each other by a circular sector 23 (namely one segment) of the central core 15a having predetermined amplitude, preferably between 40° and 260°, respectively.
The curved blade 20 is shaped for cutting a rectilinear flap 102 of the slab of cardboard 100 along the operating direction "C".
Preferably, the curved blade 20 has a cross-section (parallel to the axis of rotation of the tool) with a concave geometry, so as to define two cutting edges positioned alongside and parallel to each other, spaced apart from each other by a distance equal to the thickness of the slitting tool 15.
Advantageously, in this way it is possible to cut a flap 102 with a width equal to the thickness for defining the slot 101.
It should be noted that the first 21 and the second tip 22 are shaped to separate an end 102a of the above-mentioned flap 102 cut in order to make the slot 101.
More specifically, the first 21 and the second tip 22 are defined by respective teeth projecting radially away from the central core 15a of the slitting tool 15 and located at respective ends 20a, 20b of the curved blade 20.
In this regard, it should be noted that the control unit 27 is configured to determine the angular position of the tip 21, 22 in combination with the position of the carriage 13 so as to determine the length of the slit (that is, the slot 101).
Figures 5a to 5e illustrate the operation of the slitting tool 15 in successive operating steps.
In use, in fact, the tool 15 is rotated in such a way that the first 21 or the second tip 22 is in a predetermined angular position, so that a subsequent rotation of the curved blade 20 (that is, of the central core 15a) makes a slot of predetermined length before the separation of the flap imparted by the respective tip 21, 22.
Consequently, the slitting tool 15 comprises:

a non-operating configuration (Figure 5c) wherein the circular sector 23 of the central core 15a faces the supporting surface "A" and the spouts 21, 22 are spaced from it to allow the feeding of the slab 100;
an operating configuration (Figures 5b, 5d) wherein the tool is rotated relative to the non-operating configuration in such a way that the curved blade 20 interferes with the supporting surface "A" for cutting the slab 100. However, to allow activation of the creasing tool 14 (defined by a circular disk) the presence of a drive unit 24, preferably pneumatic, is necessary, operatively interposed between the main body 13a of the carriage 13 and the creasing tool 14 and configured for moving it towards and away from the supporting surface "A" as a function of a signal received by the control unit 27.

Similarly, there is also a further movement unit 25, operatively interposed between the main body 13a of the carriage 13 and the pressing tool 19 and configured for moving it towards and away from the supporting surface "A" as a function of a signal received by the control unit 27.
The invention achieves the proposed aims and brings significant advantages.
In effect, the presence of a transversal carriage equipped with a creasing tool and a slitting tool (as well as the pressing tool) movable in roto-translation allows an extremely versatile machine to be obtained, which is able to work both large batches and single pieces without the need for long set up times.
Moreover, the movement of these tools by a single motor and specific drive means considerably simplifies the machine structure, rendering it not only versatile but also extremely inexpensive to make.
Moreover, it should be noted that the design of the drive means which make it possible to rotate at least the slitting tool, but preferably also the creasing tool, with peripheral speed greater than the linear speed of translation of the carriage makes the processing effective, because it keeps the force on the material uniform, especially if it is a large thickness. In this description, the machine is described with reference to the working of cardboard or the like, thereby meaning any material made of slabs or sheets, either in a continuous form or in rolls, even plastic materials, such as, for example, honeycomb polypropylene, or wood.

Claims

A machine for working cardboard or the like, comprising:
- a frame (2) defining a surface (A) for supporting a slab of cardboard (100);

- means (3) for feeding the slab of cardboard (100) on the supporting surface (A) along a rectilinear direction of movement (B);

- at least a first cutting unit (5) equipped with one or more cutting blades (5a) oriented parallel to the direction of movement (A);

- at least a second cutting unit (6) equipped with one or more cutting blades (6a) oriented transversally to the direction of movement (B);
characterised in that it comprises at least one carriage (13) movable transversely to the direction of movement (B) along a relative operating direction (C) and equipped with at least one creasing tool (14), designed for making crease lines on the slab of cardboard (100), and at least one slitting tool (15), designed for making slots (101) of predetermined length on the slab of cardboard (100), both oriented parallel to the operating direction (C).
The machine according to claim 1, characterised in that the creasing tool (14) and/or the slitting tool (15) comprise at least one disc-shaped element rotatable relative to the carriage (13) about an axis of rotation substantially parallel to the direction of movement (B).
The machine according to claim 2, characterised in that:
- the creasing tool (14) and/or the slitting tool (15) have at least a central core (14a, 15a) and a peripheral portion (14b, 15b) shaped for making the crease and/or the slot (102), and

- the machine comprises actuator means (16) associated with the carriage (13) and designed for moving the creasing tool (14) and/or the slitting tool (15) in roto-translation.
The machine according to claim 3, characterised in that the actuator means (16) are designed for imparting to the peripheral portion (14b) of the creasing tool (14) a peripheral speed substantially corresponding to the translation speed of the carriage (13).
The machine according to claim 3 or 4, characterised in that it comprises a crosspiece (17b) extending along the operating direction (C) slidably coupled to a main body (13a) of the carriage (13); the actuator means (16) comprising a motor (16a) operatively interposed between the main body (13a) of the carriage (13) and the crosspiece (17b) for translating the carriage (13) along the crosspiece (17b), and drive means (18) operatively interposed between the main body (13a) of the carriage (13) and the creasing tool (14) for rotating it according to the speed of movement of the main body (13a).
The machine according to claim 5, characterised in that the drive means (18) comprise a rack (18a) rigidly connected to the crosspiece (17b) and at least one gear interposed between the rack (18a) and the creasing tool (14) for rotating it.
The machine according to any one of claims 3 to 6, characterised in that it comprises a crosspiece (17b) extending along the operating direction (C) slidably coupled to a main body (13a) of the carriage (13); the actuator means (16) comprising a motor (16a) operatively interposed between the main body (13a) of the carriage (13) and the crosspiece (17b) for translating the carriage (13) along the crosspiece (17b), and a further motor (26) coupled with the slitting tool (15) for rotating it independently of the movement of the carriage (13).
The machine according to claim 7, characterised in that the actuator means (16) are associated with a control unit (27) configured for putting in relation the speed of rotation of the further motor (26) with the speed of movement of the carriage (13) through an electronic interpolation so as to define the angular position of the slitting tool (15) in such a way as to determine the correct length of the slot (101).
The machine according to any one of the preceding claims, characterised in that the slitting tool (15) comprises a central core (15a) and a peripheral portion (15b) formed by a curved blade (20) extending about the central core (15a) between a first (21) and a second tip (22) and having an angular extension of less than 360° in such a way that the first (21) and second tip (22) are spaced from each other by a circular sector (23) of the central core (15a) having a predetermined size; the curved blade (20) being shaped for cutting a rectilinear flap (102) of the slab of cardboard (100) along the operating direction (C) and the first (21) and second tip (22) each being shaped for detaching an end (102a) of the cut flap (102) so as to make the slot (101).
The machine according to any one of the preceding claims, characterised in that the carriage (13) also comprises a pressing tool (19) designed for acting on a predetermined portion of the slab of cardboard (100) for reducing the thickness.
The machine according to claim 10, characterised in that the pressing tool (19) comprises a disc (19a) having a peripheral annular crown (19b) rotatable relative to the main body (13a) of the carriage (13).
The machine according to any one of the preceding claims, characterised in that the second cutting unit (6) and the carriage (13) are independently mobile along the operating direction (C).
The machine according to claim 12, characterised in that the second cutting unit (6) and the carriage (13) are associated with respective crosspieces (17a, 17b) extending along the operating direction (C) and arranged one after another along the direction of movement (B).