Improved creasing unit and creasing machine comprising this creasing unit

Abstract

Creasing unit (10), particularly for creasing sheets, comprising a support (30) with a shaped seat (31) configured to accommodate a die (40) with a longitudinal extension along a second extension axis (X2) and a punch (20). The shaped seat (31) is defined by a first partially cylindrical surface (32). The die (40) comprises at least two work portions (41) with a longitudinal extension parallel to the second extension axis (X2), at least two partially cylindrical second surfaces (42) complementary to this first surface (32) and rotation means (43) configured to allow the rotation of the die (40) within the shaped seat (31) about the second extension axis (X2).

Description

[0001] The invention concerns a creasing unit, particularly for creasing sheets, of a perfected type, for quick format change.

[0002] The invention also relates to a creasing machine comprising this creasing unit. Today, creasing units for creasing machines are known to be used in the printing and paper processing industry. Their main purpose is to create crease lines, folds or bindings on paper materials, such as paper or cardboard, in order to create brochures, leaflets, booklets or other types of folded documents.

[0003] Such a known type of creasing unit comprises a punch and holder coupled with a die, which comprises two grooves, of different formats, configured to accommodate the punch in order to crease the sheets.

[0004] Different format means that the two grooves have a different width.

[0005] This creasing unit also comprises magnets adapted to hold this die in place. The main limitation of this creasing unit lies in the format change of the two die grooves.

[0006] In particular, in order to perform this format change, it is necessary to perform a manual operation of removing the die from its seat and, subsequently, reinserting that die in the aforesaid seat with the format chosen by the user. However, this manual operation is slow to perform, causing prolonged machine downtime, which will affect the productivity of the creasing machine.

[0007] In addition, the operation of inserting the die is delicate to perform, and if the die is not inserted correctly into its seat, the creasing of the sheets will be defective causing material waste.

[0008] The format change operation is therefore easily susceptible to human error.

[0009] In an attempt to solve this second problem, the use of the aforementioned magnets was arrived at, which facilitate the operator in correctly inserting and retaining the die in its seat.

[0010] However, apart from being an additional element of the creasing unit that entails extra production costs these magnets are not an optimal solution as they do not guarantee a perfect fit between the die and its seat.

[0011] The task of the present invention is to develop a creasing unit, particularly for creasing sheets, capable of overcoming the aforementioned drawbacks and limits of the prior art.

[0012] In particular, it is an aim of the present invention to provide a creasing unit that allows a quick change of die format.

[0013] Furthermore, the aim of the invention is to develop a creasing unit that allows a precise fit between the die and its seat.

[0014] The above-mentioned task and aims are achieved by a creasing unit according to claim 1.

[0015] Further characteristics of the creasing unit according to claim 1 are described in the dependent claims.

[0016] The task and the aforesaid aims, together with the advantages that will be mentioned hereinafter, are indicated by the description of an embodiment of the invention, which is given by way of non-limiting example with reference to the accompanying drawings, where: Figure 1 represents a perspective view of a creasing unit according to the invention; Figure 2 represents a sectional view of the creasing unit of Figure 1; Figure 2a represents a detail of Figure 2; Figure 3 represents a front view of Figure 1; Figure 4 represents a sectional side view of Figure 3; Figure 5 represents the same view as Figure 4 with the creasing unit in a different operating position; Figure 6 represents a perspective view of the creasing unit in the operating position of Figure 5; Figure 7 represents a perspective exploded view of the creasing unit of Figure 1; Figure 8 represents a perspective view of an element of the creasing unit of Figure 1; Figure 9 represents a detail of the element of Figure 8; Figure 10 represents a detail of some elements of the creasing unit of the invention; Figure 11 represents a side view of a detail shown in a sectional view of Figure 3; Figure 12 represents a perspective view of a creasing unit according to the invention; Figure 13 represents a further perspective view of the creasing unit of Figure 12.

[0017] With reference to the above-mentioned figures, a creasing unit, particularly for creasing sheets, according to the invention is indicated as a whole by the number 10 , clearly visible in Figures 1, 3, 6 and 7.

[0018] This creasing unit 10 comprises: a support 30 with a shaped seat 31 extending longitudinally along a first extension axis X and configured to accommodate a die 40 extending longitudinally along a second extension axis X2 ; this die 40 inserted into the shaped seat 31 ; a punch 20 with longitudinal extension along a third extension axis X3 .

[0019] This punch 20 is arranged above the shaped seat 31 and the die 40 so that the third extension axis X3 is parallel to the first extension axis X and to said second extension axis X2 .

[0020] Furthermore, the punch 20 is configured to translate along a translation axis Y orthogonal to the first extension axis X , the second extension axis X2 and the third extension axis X3 , so that said punch 20 is able to move towards / away from said support 30 and said die 40 , as visible in Figures 4, 5 and 6.

[0021] The shaped seat 31 , clearly visible in Figure 10, is defined by a first partially cylindrical surface 32 .

[0022] Preferably, this first surface 32 is semi-cylindrical.

[0023] In the context of this description, a first partially cylindrical surface is understood to mean that this first surface 32 partially defines the side wall of a cylinder.

[0024] The die 40 , clearly visible individually in Figures 8 and 9, comprises at least two work portions 41 with a longitudinal extension parallel to the second extension axis X2 .

[0025] As can be seen in Figures 5 and 6, each of these two work portions 41 is configured to accommodate the aforementioned punch 20 in order to process, specifically crease, the sheets.

[0026] In a possible embodiment of the invention, at least one of these two work portions 41 is a groove 41a .

[0027] In particular, both of these work portions 41 are grooves 41a .

[0028] In particular, the two grooves 41a have different formats.

[0029] Different formats mean that the two grooves have a different shape, e.g. a different depth or a different width.

[0030] Obviously, these different formats allow for different creasing lines on the sheets.

[0031] Continuing to describe the preferred embodiment of the invention, the die 40 comprises at least two partially cylindrical second surfaces 42 complementary to this first surface 32 .

[0032] In particular, these at least two second surfaces 42 partially define, subject to mechanical tolerances, the side walls of the cylinder defined by the first surface 32 .

[0033] The die 40 also comprises rotation means 43 configured to allow the rotation of the die 40 within the shaped seat 31 about the second extension axis X2 . Specifically, these rotation means 43 are two pins projecting from the ends 45 of the die 40 and running along the second extension axis X2 .

[0034] Obviously these rotation means 43 are connected to motion inducing means, particularly an electric motor, configured to induce the aforementioned rotation of the die 40 about the second extension axis X2 .

[0035] The creasing unit 10 enables rapid format change of the die grooves.

[0036] In fact, in order to change the format of the die grooves, it will not be necessary to perform the operation of withdrawing and reinserting the die in its seat. Instead, to perform the format change, it will be sufficient to rotate the die 40 by the aforementioned rotation means 43 about the second extension axis X2 . It is emphasised that the format change operation consists of rotating the die so as to change the groove facing the punch. These grooves have different formats, meaning a different height or width of the groove.

[0037] Obviously, this operation is carried out while keeping the die in the shaped seat.

[0038] This will make the format change operation quick and easy to perform.

[0039] In addition, there will be a precise coupling between the die 40 and the shaped seat 31 .

[0040] In particular, the two second surfaces 42 complementary to this first surface 32 ensure a precise coupling between the die 40 and the shaped seat 31 .

[0041] It should be specified that the two work portions 41 and these at least two second surfaces 42 are circumferentially alternating with each other.

[0042] It is also good to specify that the support 30 comprises an upper wall 36 .

[0043] The aforementioned shaped seat 31 is formed in this upper wall 36 .

[0044] A further advantage of the invention lies in the fact that the particular conformation of the creasing unit 10 allows the die to be rotated while maintaining the position of the support 30 during the format change.

[0045] In particular, the fact that the shaped seat 31 and the two second surfaces 42 are partially cylindrical and complementary allows the die to rotate about the second extension axis X2 during the format change operation, remaining within the shaped seat 31 while the support 30 remains in a fixed position.

[0046] This, in turn, makes it possible to keep the upper wall 36 of the support 30 aligned and contiguous with both the entry plane of a creasing machine and the exit plane of the same creasing machine, in which the creasing unit of the invention is inserted, both during the creasing machine's processing steps and during the format change operation.

[0047] There is therefore no need to change the mutual arrangement of the entry and exit planes with respect to the creasing unit during the latter's format change, allowing the same creasing unit to be used in automatic creasing systems or apparatus.

[0048] In the preferred embodiment of the invention, each of the at least two work portions 41 is formed on a flat surface 44, 44a of said die 40 configured to be aligned with the upper wall 36 of the support 30 when the corresponding work portion 41 is facing the punch 20 so as to accommodate the punch 20 and allow the processing of a sheet.

[0049] In particular, each of said at least two grooves 41a is formed on the flat surface 44, 44a of this die 40 configured to be aligned with the upper wall 36 of the support 30 when the corresponding groove faces the punch 20 so as to accommodate the punch 20 and allow creasing of a sheet.

[0050] This configuration allows for an alignment between the flat surface 44, 44a and the upper wall 36 of the support 30, as observed in Figures 2, 2a, 4, 5 and 11. Advantageously, this configuration allows the sheet to be placed on flat, aligned surfaces.

[0051] It should be specified that, in the preferred embodiment of the invention, these at least two work portions 41 are diametrically opposed to each other and the corresponding flat surfaces 44, 44a are parallel to each other.

[0052] In particular, these at least two grooves 41a are diametrically opposed to each other and the corresponding flat surfaces 44, 44a are parallel to each other. Therefore, in this configuration, there is a radial distance of 180° between the two grooves 41a .

[0053] Obviously, this configuration is feasible when the die comprises an even number of grooves and corresponding flat surfaces.

[0054] Alternatively, a possible configuration of the invention involves the grooves being positioned at the vertices of a regular polygon inscribed in the circumference defined by the two second surfaces.

[0055] In particular, one possible configuration of the invention involves three work portions 41 spaced apart by an angle of 120°.

[0056] Continuing to describe the preferred embodiment of the invention, the creasing unit 10 comprises locking means 50 adapted to lock in at least two positions the rotation of the die 40 about the second extension axis X2 , in such a way that in each of said at least two positions one of said at least two work portions 41 is facing the punch 20 and can accommodate said punch 20 and allow the processing, in particular the creasing, of a sheet.

[0057] It should also be specified that, in the preferred embodiment of the invention, the locking means 50 comprise at least one plate 51 firmly associated with the support 30 .

[0058] It is not excluded that these locking means comprise additional or alternative elements to lock the rotation of the die 40 .

[0059] In a possible alternative version of the invention, the locking means 50 are comprised in the motion induction means. It is understood, therefore, that these motion induction means are configured to induce the rotation of the die 40 and lock that die 40 in such at least two positions.

[0060] In a possible embodiment of the invention, at least one of the two work portions 41 is made of polymer material.

[0061] In particular, this at least one of these two work portions 41 is a flat surface made of polymer material.

[0062] In particular, this at least one of these two work portions 41 is made of polytetrafluoroethylene.

[0063] In this embodiment, the punch 20 has a serrated tip. This serrated tip allows the sheet to be perforated when this work portion 41 made of polymer material is facing this punch 20 and this punch 20 is accommodated in this work portion 41 .

[0064] It is therefore emphasised that, in this embodiment of the invention, the creasing unit 10 is capable of performing a discrete perforation on the sheet in such a way as to create a series of in-line holes.

[0065] This series of holes in a line facilitates the tearing of this sheet along this line.

[0066] Returning to the preferred embodiment of the invention, the die 40 has, at at least one of its ends 45 , an abutment portion 46 , clearly visible in Figures 8 and 9, configured to abut on the plate 51 so as to block the rotation of the die 40 about the second extension axis X2 in these at least two positions, as visible in Figure 11.

[0067] Preferably, the locking means 50 comprise two plates 51 firmly associated with the support 30 .

[0068] In addition, the die 40 has, at both of its ends 45 , an abutment portion 46 configured to abut on these two plates 51 so as to block the rotation of the die 40 about the third axis X3 in these at least two positions.

[0069] It is noted that the die 40 has, at this at least one end 45 thereof, a hollow 47 , clearly visible in Figures 8 and 9, with a depth D1 with respect to the abutment portion 46 such as to permit a partial rotation of said die 40 about said second extension axis X2 in conjunction with a recess 52 defined in said plate 51 and facing the die 40 .

[0070] It can be observed that, in the preferred embodiment of the invention, the die 40 has, at both its ends 45 , such a hollow 47 .

[0071] In the preferred embodiment of the invention both plates 51 have the recess 52 .

[0072] In particular, as can be seen in Figure 11, the distance R1 of the face 47a of the hollow 47 from the second extension axis X2 is less than the minimum distance D2 of this recess 52 from the second extension axis X2 .

[0073] In addition, the maximum distance R2 of the abutment portion 46 from the second extension axis X2 is greater than the aforementioned minimum distance D2 .

[0074] This configuration allows the rotation of this die 40 about the second extension axis X2 between these at least two positions.

[0075] In particular, this rotation is 180°. This rotation can be either clockwise or anticlockwise.

[0076] Continuing with the description of the creasing unit 10 according to the invention, it can be seen that the support 30 comprises at least one bridge 35 configured to allow attachment of the locking means 50 .

[0077] In particular, the support 30 comprises this at least one bridge 35 , clearly visible in Figures 2a and 10, configured to allow the attachment of the plate 51 .

[0078] This attachment is carried out by means of joining means, e.g. screws or pins, inserted into coaxial and through holes defined on said plate 51 and said bridge 35 .

[0079] Preferably, this bridge 35 is defined in the vicinity of one end of this support 30 . Furthermore, in the preferred embodiment of the invention, the support 30 comprises two bridges 35 configured to allow the attachment of the locking means 50 .

[0080] In particular, the support 30 comprises two bridges 35 configured to allow the attachment of the two plates 51 .

[0081] These two bridges 35 are defined near both ends of this support 30 .

[0082] Said support 30 comprises at least one side wall 33 on which a through-hole 34 is defined communicating with the shaped seat 31 and configured to allow insertion and disengagement of the die 40 into / from said shaped seat 31 .

[0083] In the preferred embodiment of the invention, the through hole 34 is defined on both side walls 33 of the support 30 and the support 30 comprises at least one bridge 35 configured to allow the attachment of the locking means 50 .

[0084] These through-holes 34 are configured to allow the passage of the rotation means 43 and possibly their connection to the motion induction means.

[0085] In particular, these through holes are configured to allow the passage of the two pins.

[0086] It is good to specify that the creasing unit 10 comprises movement means configured to allow the punch 20 to move along the translation axis Y .

[0087] The invention also relates to a creasing machine 100 , shown in Figures 12 and 13, for creasing sheets.

[0088] This creasing machine 100 comprises an inlet portion 101 , into which the sheets to be folded are allowed to enter, and an outlet portion 102 , which allows the folded sheets to exit.

[0089] This creasing machine 100 defines a feed direction Z of the sheets between the inlet portion 101 and the outlet portion 102 .

[0090] The creasing machine 100 comprises a creasing unit 10 for creasing sheets. This creasing unit 10 is arranged between the inlet portion 101 and said outlet portion 102 in a transverse direction to the feed direction Z .

[0091] The uniqueness of this creasing machine 100 lies in the fact that this creasing unit 10 is made as described above.

[0092] It has thus been established that the invention achieves the intended task and objects.

[0093] In particular, with the invention, a creasing unit has been developed that allows a rapid die format change.

[0094] In addition, a creasing unit has been developed that allows a precise coupling between the die and its seat.

Claims

1. Creasing unit (10), particularly for creasing sheets, comprising: - a support (30) with a shaped seat (31) extending longitudinally along a first extension axis (X) and configured to accommodate a die (40) extending longitudinally along a second extension axis (X2); - said die (40) inserted into said shaped seat (31); - a punch (20) longitudinally extending along a third extension axis (X3), said punch (20) being arranged above said shaped seat (31) and said die (40) so that said third extension axis (X3) is parallel to said first extension axis (X) and to said second extension axis (X2), said punch (20) being configured to translate along a translation axis (Y) orthogonal to said first extension axis (X), to said second extension axis (X2) and to said third extension axis (X3), so that said punch (20) is able to move towards / away from said support (30) and said die (40); characterised in that: - said shaped seat (31) is defined by a first partially cylindrical surface (32); - said die (40) comprises at least two work portions (41) having a longitudinal extension parallel to said second extension axis (X2), at least two partially cylindrical second surfaces (42) complementary to said first surface (32), and rotation means (43) configured to allow rotation of said die (40) within said shaped seat (31) about said second extension axis (X2).

2. Creasing unit (10) according to claim 1, characterised in that said at least two work portions (41) and said at least two second surfaces (42) are circumferentially alternating with each other.

3. Creasing unit (10) according to claim 1 or 2, characterised in that each of said at least two work portions (41) is formed on a flat surface (44, 44a) of said die (40) configured to be aligned with the upper wall (36) of said support (30) when the corresponding work portion is facing said punch (20) so as to be able to accommodate said punch (20) and allow the processing, in particular creasing, of a sheet.

4. Creasing unit (10) according to claim 3, characterised in that said at least two work portions (41) are defined diametrically opposed to each other and the corresponding flat surfaces (44, 44a) are parallel to each other.

5. Creasing unit (10) according to any one of the preceding claims, characterised in that it includes locking means (50) adapted to lock in at least two positions said rotation of said die (40) about said second extension axis (X2) in such a way that in each of said at least two positions one of said at least two work portions (41) is facing said punch (20), being able to accept said punch (20) and to allow the processing, in particular the creasing, of a sheet.

6. Creasing unit (10) according to claim 5, characterised in that said locking means (50) comprise at least one plate (51) firmly associated with said support (30), said die (40) presenting, at at least one end (45) thereof, an abutment portion (46) configured to abut on said plate (51) so as to block the rotation of said die (40) about said second extension axis (X2) in said at least two positions.

7. Creasing unit (10) according to claim 6, characterised in that said die (40) has, at said at least one end (45) thereof, a hollow (47) with a depth (D1) with respect to said abutment portion (46) such as to allow a partial rotation of said die (40) about said second extension axis (X2) in cooperation with a recess (52) defined in said plate (51) and facing said die (40).

8. Creasing unit (10) according to claim 7, characterised in that: - the distance (R1) of the face (47a) of said hollow (47) from said second extension axis (X2) is less than the minimum distance (D2) of said recess (52) from said second extension axis (X2); - the maximum distance (R2) of said abutment portion (46) from said second extension axis (X2) is greater than said minimum distance (D2).

9. Creasing unit (10) according to any one of claims 5 to 8, characterised in that said support (30) comprises at least one bridge (35) configured to allow attachment of said locking means (50).

10. Creasing unit (10) according to any one of the preceding claims, characterised in that said support (30) comprises at least one side wall (33) on which a through hole (34) communicating with said shaped seat (31) and configured to allow insertion and disengagement of said die (40) into / from said shaped seat (31) is defined.

11. Creasing unit (10) according to any one of the preceding claims, characterised in that it comprises movement means configured to allow the translation of said punch (20) along said translation axis (Y).

12. Creasing unit (10) according to any one of the preceding claims, characterised in that at least one of said two work portions (41) is made of polymer material, and that said punch has a serrated tip.

13. Creasing unit (10) according to any one of the preceding claims, characterised in that at least one of said two work portions (41) is a groove (41a).

14. Creasing machine (100) for creasing sheets, comprising: - an inlet portion (101) into which the sheets to be folded are allowed to enter and an outlet portion (102) which allows the folded sheets to exit, said creasing machine (100) defining a feed direction (Z) of said sheets between said inlet portion (101) and said outlet portion (102); - a creasing unit (10) for creasing said sheets, said creasing unit (10) being arranged between said inlet portion (101) and said outlet portion (102) in a direction transverse to said feed direction (Z), characterised in that said creasing unit (10) is made according to any one of the preceding claims.

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