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Title:
IMPROVEMENTS TO A BUNDLE BREAKER AND METHOD FOR ITS OPERATION
Document Type and Number:
WIPO Patent Application WO/2008/129579
Kind Code:
A2
Abstract:
A breaker of stacks or bundles of blanks obtained on superposed sheets by means of transverse cut lines comprising at least one first lower support (3; 103) and at least one second lower support (5; 105) placed side by side and distanced from each other; at least one first upper grip means (7; 107) and respectively at least one second upper grip means (9; 109) associated to each of said at least one first and second support (3; 103; 5; 105) to grip respective parts of a stack (P) of sheets placing a cutting line (T) between said at least one first and second support (3, 5; 103, 105) and between said at least one first and second grip means (7, 9; 107, 109); at least one main actuator (32A, 32B) to move vertically said first and second upper grip means (7; 107; 9; 109) in such a way as to compact or block the stack (P) of sheets on said at least one first and second support (3, 5; 103, 105); at least one first lower actuator (23A, 23B; 123A, 123B) and at least one first upper actuator (33A, 33B; 133A, 133B) to move vertically said at least one second support (5; 105) and respectively said second grip means (9; 109) perpendicularly to the direction of feeding of the stack (P) of sheets along an axis parallel to the cutting line (T); at least one second lower actuator (27; 121) and at least one second upper actuator (37; 131) to move said at least one second support (5; 105) and respectively said at least one second grip means (9; 109) reciprocatingly in transverse direction relative to the direction of advance of the stack (P) of sheets.

Inventors:
LANDUCCI PIERO (IT)
Application Number:
IT2008/000256
Publication Date:
October 30, 2008
Filing Date:
April 16, 2008
Export Citation:
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Assignee:
TENACE S R L (IT)
LANDUCCI PIERO (IT)
International Classes:
B26D7/18; B26F3/00; B65H35/10
Foreign References:
EP1369213A22003-12-10
US4500022A1985-02-19
US4136604A1979-01-30
Attorney, Agent or Firm:
MANNUCCI, Michele et al. (Via della Scala 4, Firenze, IT)
Download PDF:
Claims:

CLAIMS

1) A breaker of stacks or bundles of blanks obtained on superposed sheets by means of transverse cutting lines (T) comprising:

> at least one first lower support (3; 103) and at least one second lower support (5; 105) flanking each other and mutually distanced;

> at least one first upper grip means (7; 107) and respectively at least one second upper grip means (9; 109) associated to each of said at least first and second support (3; 103; 5; 105) to grip respective parts of a stack (P) of sheets placing one of said cutting lines (T) between said at least first and second support (3, 5; 103, 105) and between said first and second grip means (7, 9; 107, 109);

> at least one main actuator (32A, 32B) to move vertically said first and second upper grip means (7; 107; 9; 109) in such a way as to compact or block the stack (P) of sheets on said at least one first and second support (3, 5; 103, 105);

> at least one first lower actuator (23A, 23B; 123A, 123B) and at least one first upper actuator (33A, 33B; 133A, 133B) to move vertically said at least one second support (5; 105) and respectively said second grip means (9; 109) perpendicularly to the direction of feeding of the stack (P) of sheets along an axis parallel to the cutting line (T);

> at least one second lower actuator (27; 121) and at least one second upper actuator (37; 131) to move said at least one second support (5; 105) and respectively said at least one second grip means (9; 109) reciprocatingly in transverse direction relative to the direction of advance (FA) of the stack (P) of sheets.

2) The bundle breaker as claimed in claim 1, characterized in that it comprises at least one additional lower actuator (25A 3 25B; 161) and at least one additional upper actuator (35A, 35B; 162) to translate said at least one second support (5; 105) and respectively said at least one second grip means (9; 109) in the direction of advance (FA) of the stack (P) of sheets.

3) The bundle breaker as claimed in claim 1 and/or 2, characterized in that at least one of the following: said at least one main actuator (32A, 32B), said at least one first actuator (23A, 23B; 33A, 33B; 133A, 133B; 123A, 123B), said at least one second actuator (27, 37; 121, 131) and said at least one additional actuator (25A, 25B; 35A, 35B; 161, 162) is obtained with double acting mechanical devices, such as for example hydraulic or pneumatic jacks or pistons or electric motors or others.

4) The bundle breaker as claimed in at least one of the previous claims, characterized in that said at least one first actuator (23A, 23B; 33A, 33B; 133A 5 133B; 123 A, 123B), said at least one second actuator (27, 37; 121, 131) and said at least one additional actuator (25A, 25B; 35A, 35B; 161, 162) are connected to a frame (2) of the separator by means of mechanisms comprising ball joints (23N, 23M 5. 25N 5 25M, 27N, 27M) or rotary connecting joints (123N, 123K, 123R, 123M; 133N 5 133K 5 133R 5 133M).

5) The bundle breaker as claimed in at least one of the previous claims, characterized in that it comprises a plurality of actuators (23A 5 23B; 123A 5 123B; 33A 5 33B; 133A 5 133B; 27; 121; 37; 131; 25A; 25B; 161; 35A; 35B; 162) to move in at least three mutually perpendicular directions (F2; F3; F4) said at least one second support (5; 105) together with said at least one second grip means (9; 109) with respect to said at least one first support (3; 103) and respectively to said at least one first grip means (7; 107); said movements being performed alternatively to, or in combination with each other, e.g. in succession or simultaneously.

6) The bundle breaker as claimed in claim 7, characterized in that at least one of said movements (F2; F3; F4) is scissors-like.

7) The bundle breaker as claimed in at least one of the previous claims, characterized in that it comprises an adjustment mechanism for adjusting the mutual distance between said at least one first lower support (3; 103) and said at least one second lower support (5; 105) and/or between said at least one first upper grip means (7; 107) and said at least one second upper grip means (9; 109); said adjustment mechanism being mechanical or pneumatic or hydraulic or the like.

8) The bundle breaker according to at least one of the previous claims, characterized in that it comprises an adjustment mechanism commanded manually or via software by an operator to adjust the mutual distance between said at least one first lower support (3; 103) and said at least one second lower support (5; 105).

9) The bundle breaker as claimed in at least one of the previous claims, characterized in that it comprises respective stationary blades (59, 60) positioned transversely on said at least one first and respectively second lower support (3; 103; 5; 105) to define said cutting line (T) more precisely and to improve the shearing of said cutting line (T).

10) The bundle breaker as claimed in claim 9, characterized in that said stationary blades (59, 60) can be adjusted in height and/or adjustable vertically in a

support (59 1 A, 60A) fastened on said at least one first and respectively second lower support (3; 5) by means of respective threaded screws (59B; 60B).

11) The bundle breaker as claimed in at least one of the previous claims, characterized in that it comprises a first and a second lower plate (7A; 9A) for contacting and cutting the stack (P) of sheets, associated to said first and respectively second grip means (7; 9; 107; 198) and whose mutual distance can be adjusted manually or with automatic actuators, pneumatic or hydraulic or otherwise motorized, in such a way as to work as close as possible to said cutting line (T) to be broken.

12) A method for separating or cutting a stack (P) of sheets comprising transverse and superposed cutting lines (T), characterized in that it comprises the following steps:

> feeding said stack (P) of sheets on a first support (3; 103) according to a direction of feeding (FA) and subsequently on second supports (5; 105) flanking, and distanced fi-om, said first supports (3; 103); > compacting or locking the stack (P) of sheets on said first support (3; 103) and second support (5; 105) through first grip means (7; 107) and respectively second grip means (9; 109), so that one of said cutting lines (T) is positioned between said first support (3; 103) and said second support (5; 105) and between said first grip means (7; 107) and said second grip means (9; 109); > moving vertically said second support (5; 105) together with said second grip means (9; 109) to break the cutting line (T) positioned between the aforesaid first and second elements perpendicularly to the direction of feeding (FA) of the stack (P) of sheets;

> moving alternatively in transverse direction relative to the direction of feeding (FA) of the stack (P) of sheets the second support (5; 105) together with the related second grip means (9; 109);

> making the stack (P) of sheets advance to break successive cutting lines (T).

13) The method as claimed in claim 12, characterized in that the transverse actuation step takes place simultaneously or in succession to the vertical actuation step. 14) The method as claimed in claim 13, characterized in that it comprises a step in which said second support (5; 105) is thrust forwards along the direction of feeding (FA) of the stack (P) of sheets together with said second grip means (9; 109) with a translatory motion or with a scissors-like motion said forwards thrust step is activated simultaneously or in succession or else alternatively to the aforesaid vertical actuation

step.

Description:

"IMPROVEMENTS TO A BUNDLE BREAKER AND METHOD FOR ITS OPERATION"

DESCRIPTION Technical Field The present invention relates to a breaker for separating stacks or bundles of shaped blanks obtained by means of cutting lines on a plurality of superposed sheets made of a semi-rigid material, and to a related method for consecutively separating each stack of blanks along v a transverse cutting line.

State of the Art In the paper industry, the use is generally known of cutters or bundle breakers for sheets or foils made of semi-rigid material, such as paper or cardboard, whereon are planar developments or template, hereafter called "blanks", able to be successively folded several times to obtain boxes, containers and cases for packing or packaging or other purposes. The blank has a shape able to provide the container with given characteristics or shapes or to allow particular simplicity in the construction of the container itself and as a rule it is obtained by die cutting on the semi-rigid sheet by means of die-cutting presses.

Die cutting consists, briefly, of performing a cut on the semi-rigid sheet while leaving points or bridge portions of material, in such a way as to define the edges and the shape of each contoured blank keeping mutually joined adjacent contoured blanks on the same sheet.

The use is known of machines, also called bundle breakers, able to cut or separate a plurality of contoured blanks obtained on stacked sheets, in order considerably to increase the production rate.

Briefly, a plurality of die-cut sheets are superposed on each other by means of automatic stacking machines; subsequently, these stacks are fed in a bundle breaker to break up to points or bridge portions of the die cutting operation, detaching a stack of blanks from the adjacent one. Lastly, the blanks are fed into folding machines to obtain the box or the container.

For example, the patent US-B-4,136,604 discloses a bundle breaker which comprises a first and a second support, first and respectively second grip means mounted on each support to grip respective parts of a stack of die cut sheets with contoured blanks, an oscillating device which makes one of the supports oscillate relative to the other starting

from a substantially aligned or coplanar position in such a way as to break the die cut lines and to separate the blanks. This oscillation motion takes place in a plane that is perpendicular relative to the plane of sliding of the stack of sheets. Moreover, vertical guide elements are provided to prevent the lateral flexion of the oscillation motion and hence to limit this same motion in the vertical plane.

The main drawback of this type of machine is that it requires a considerable cutting force because all the sheets of a same stack have to be cut at the same time; the sheets and the blanks can therefore be damaged during the separation process.

In particular, since both the contact surfaces of the grip means and of the oscillating device are rigid, a greater pressure is exerted on the higher sheets of the stacks and this pressure can damage the semi-rigid material, e.g. the corrugated cardboard. On the contrary, if the material whereof the sheets are made is less compressible - e.g. plastic- coated cardboard sheets - it may happen that the exerted pressure is insufficient for the separation of the lowest sheets in the stack, which can slip during the work process without being cut.

To try to solve these drawbacks, bundle breakers have been developed that break the die cutting lines thanks to a rotary cut system around a pivot relative to the vertical breaking plane, in such a way as progressively to break the stack of die-cut sheets along this plane; machines are also known which adopt springs or air cushions on the contact surface of the grip means to try to uniform the pressure exerted on the stack of sheets.

This type of machine generally enables work processes that apply less mechanical stress to the material being worked.

Such a machine is described for example in EP-B- 1,369,315 in which a first transport device for stacks of die cut sheets presents an upstream end to receive the stacks of sheets and a downstream end; a second transport device presents an upstream end positioned immediately adjacent to the downstream end of the first transport device and distanced therefrom to define a breaking plane for the stack; first grip means are mounted in such a way as to move vertically above the first transport device and second grip means are mounted in such a way as to move vertically above the second transport device. The second transport device and the second grip means are mounted in such a way as to rotate jointly around a pivot relative to the breaking plane and to cut the die cutting line. The first and second grip means comprise respective flexible, pressurized structures to grip the upper surfaces upstream and respectively downstream of the stack of sheets.

Bundle breakers have also been devised which enable to obtain particular work phases, in order to facilitate and speed up the separation of the die cut sheets in determined configurations.

For example, US-A-4,500,022 discloses a bundle breaker that comprises a movable upper casing guided by an articulated parallelogram formed by lower connecting rods and by upper connecting rods, an upper plane positioned within the movable upper casing and a lower plane positioned within a lower casing. The upper and lower planes are formed each by a fixed plane and by a slidable plane, which are provided with four movable boards positioned two by two matching each other on the fixed plane and respectively on the slidable plane. On the lower casing is also provided a conveyor belt to move the stacks of sheets to be divided. The two movable boards positioned on the slidable plane are laterally guided in a window formed in the slidable plane by means of rollers and at the same time they are guided in the horizontal plane by means of additional rollers which roll on the slidable plane. Similarly, the two movable boards positioned on the fixed plane are laterally guided in a window formed in the fixed plane by means of rollers and in the horizontal plane by means of additional rollers which roll on the fixed plane.

The four movable tables are displaced by means of respective jacks whose axes of action are displaced relative to the theoretical axis of the movable boards, such as to allow the separation of the blanks with a 45 degree movement with respect to the direction of sliding of the stacks of sheets.

In particular, this machine has a main configuration in which the blanks, die cut on each sheet in two mutually flanking rows, are fed to the bundle breaker that separates them by means of a transverse movement at 45 degrees relative to the direction of feeding, obtained from the combination of a forward motion of the slidable plane and of a lateral motion of the aforesaid two pairs of movable boards.

In other words, the cutting lines of the die cut sheets are broken at the same time according to two perpendicular directions, according to the length and the width of the die cut sheet. In this way, the need is avoided to rotate by 90 degrees the sheets which must be separated on die cutting lines according to two orthogonal axes, therefore avoiding having to provide two successive separation stations or steps.

In a secondary configuration of the bundle breaker disclosed in US-A-4,500,022 a pack of sheets is fed with die cut blanks that occupy the entire width of the sheet, i.e.

arranged in a single row in the direction of advance. In this case, the blanks are separated by the forward sliding of the slidable plane, and therefore the movable boards undergo no lateral displacement.

Additionally, EP- A- 1,369,213 discloses a bundle breaker comprising two pairs of transport means to move a stack of die cut sheets in longitudinal direction; two pairs of upper grip means to lock the stacks of die cut sheets against the respective transport means; first actuators to rotate around a pivot one of the two pairs of grip means together with the respective pair of transport means on a transverse cutting line with respect to the stack of die cut sheets; and second actuators to move in transverse direction a pair of the grip means and the respective pair of the transport means on both the sides of a longitudinal cutting line relative to the stack of die cut sheets. In this case, the aforesaid first actuators truncate a transverse cutting line of the stack; the aforesaid second actuators distance in the transverse direction two mutually flanking pairs of grip means in such a way as to cut a longitudinal cutting line of the stack. In this case, too, the need is avoided to rotate by 90 degrees two mutually flanking rows of sheets which must be separated according to two orthogonal axes, therefore avoiding having to provide a rotary board and a successive separation station.

Additional bundle breakers are disclosed in US-A-5,791,539; EP-A-1, 524,224; US- A-5,927,582 and in US-B-4,987,723; US-A-5,573,488; EP-B-0,404,909 and in US-B- 4,706,532.

A disadvantage of the bundle breakers described above is that it is not possible automatically to separate contoured blanks that have undercut tabs or teeth, i.e. which project transversely relative to the direction of feeding of the stack of sheets.

These undercut teeth are generally provided to facilitate the closing of particular types of containers, e.g. some types of shoe boxes or containers for take-out pizza or others.

In this case, generally, an operator separates the stacks of blanks manually, once these stacks are cut by the machine; alternatively, an additional machine can be provided at the output of the bundle breaker to separate a stack from the other in transverse direction.

Another disadvantage is that the progressive rotary or pivot cutting system may compromise the separation of the sheets that are closest to the point of rotation, especially when the stack of sheets presents considerable height. Oftentimes, additional steps or additional machines need to be provided, in order to separate the last die cutting

points of the closest sheets to the point of rotation, increasing both manufacturing costs and times.

An additional disadvantage is that the machines that comprise the progressive rotary or pivotal cutting system are complex in their construction and use. To date, in spite of technological development, it is problematic and there is a need to obtain simple, low cost bundle breakers to detach or cut contoured blanks in a faster and more economical manner, while manufacturing an improved, high quality finished product.

Objects and Summary of the Invention An object of the present invention is to provide a bundle breaker whose construction is more economical and simpler, which enables to cut a stack of sheets, especially die cut sheets, more easily and/or more quickly.

One object of a particular embodiment of the invention is to enable to cut a stack of sheets presenting contoured blanks defined by transverse cut lines with particular profiles, in order to overcome or at least partly reduce the aforesaid disadvantages.

An object of another particular embodiment is to optimize the cutting step, preferably obtained with a cutting motion perpendicular to the direction of advance of the stack of sheets, increasing the operating speed of the machine and the quality of the finished product. An additional object of the present invention is to provide a method that enables to cut in an automated manner a stack of sheets presenting transverse cutting lines, specifically die cut sheets with cutting lines having particular profiles.

According to a first aspect, the invention relates to a breaker of stacks or bundles of blanks obtained on superposed sheets by means of transverse cutting lines, which comprises:

> at least one first lower support and one second lower support flanking each other and mutually distanced;

> at least one first upper grip means and respectively one second upper grip means associated to each of the supports to grip respective parts of a stack of sheets which comprises a cutting line positioned between the first and second support and between the first and second grip means;

> at least one main actuator to move vertically the first and second upper grip means in such a way as to compact or block the stack of sheets on the first and second support;

> at least one first lower actuator and at least one first upper actuator to move

vertically the second support and respectively the second grip means perpendicularly to the direction of feeding of the stack, of sheets along an axis parallel to the cutting line; > at least one second lower actuator and at least one second tipper actuator to move the second support and respectively the second grip means reciprocatingly in transverse direction relative to the direction of advance of the stack of sheets.

The term "cutting line" means a line of weakened material obtained transversely on the sheet relative to the direction of advance, of a different type depending on the material used, semi-rigid or fragile, able to form sheets divisible by cutting.

In particular, if this material is paper, cardboard or the like, the cutting line can be obtained by die cutting; if the material is plastic or a plastic compound, the cutting line can be obtained by weakening with a notch the surface of the same material; if it is wood (e.g. very thin wood planks) or other semi-rigid material, the cutting line could be obtained with a strip of adhesive tape or paper or with hot-poured glue points that created joining bridges, or in yet other ways. The aforesaid lateral motion of the second grip means serves, advantageously and preferably, the purpose of detaching or freeing a blank from the next blank if the contoured blanks have undercut tabs or teeth, i.e. tabs or teeth that project transversely relative to the direction of feeding of the stack of sheets, see description below.

In a particularly advantageous embodiment of the invention, the first lower actuator and the first upper actuator are obtained with pairs of upper and respectively lower actuators; each actuator of the respective pair is activated in succession, in order to obtain a vertical scissors-like movement of the second support and respectively of the second grip means in order gradually to break the cutting lines and to start from an edge to the opposite end of the stack of sheets, see description below. It is thereby possible to exert a smaller cutting force than the force that must be exerted in the case of the translatory vertical motion, thus reducing the possibility of damaging the material.

Moreover, considering that the compression force needed to block or compact the stack of sheets is substantially proportional to the cutting force (assuming the friction coefficient to be constant), it is extremely useful to reduce the cutting force as much as possible to reduce the compression force, mrther reducing the possibility of damaging the material.

Clearly, in any case, the possibility of activating the aforesaid pairs of first actuators simultaneously cannot be excluded, in order to translate vertically the second support

and the related second grip means with a motion that is parallel to the plane of advance of the stacks of sheets, see below.

In an advantageous embodiment at least one additional lower actuator and at least one additional upper actuator are provided to translate the second support and respectively the second grip means forward, i.e. in the direction of advance of the stack of sheets.

Advantageously, these additional upper and lower actuators are made with pairs of additional upper and respectively lower actuators; each additional actuator of the respective pair can be activated in combination with the aforesaid first and/or second actuators in such a way as to obtain a diagonal and downward cutting motion able to break any fibers still joined and to clean the cut from the residues of material; it cannot be excluded that these additional actuators may be activated reciprocatingly to the first actuators, see description below.

The first and the second actuators, and possibly also the additional actuators, are advantageously and preferably obtained with double acting mechanical devices, e.g. hydraulic or pneumatic jacks or pistons, and they are connected to the fixed frame by means of mechanisms comprising ball joints that enable the aforesaid movements along the three directions in a simple and fast manner, or rotary connecting joints, see detailed description below. The first and the second actuators and the additional actuators may in any case be embodied by different mechanical devices, e.g. electric motors or others.

In sum, the bundle breaker of the aforesaid type comprises a plurality of actuators to move in at least three directions, substantially parallel to each other, at least the second support and the related second grip means relative to the first support and to the related first grip means.

In particular, these three movements along three directions can be performed alternatively or in combination with each other, specifically in succession or simultaneously, see below.

According to another particularly relevant aspect of the invention, an adjustment mechanism is provided for adjusting the mutual distance between the first and the second support of the bundle breaker, in order to work as closely as possible to a transverse cutting line.

This adjustment mechanism can be mechanical or pneumatic or hydraulic and it can be commanded manually or via software by an operator.

Advantageously, a similar adjustment mechanism can be provided to adjust the distance between the &st and the second upper grip means.

In one embodiment, an adjustment mechanism . of the aforesaid type is able to translate simultaneously both supports, or both grip means, in such a way as to move them closer or farther away from each other.

In another embodiment, an adjustment mechanism of the aforesaid type is able to approach or distance only one support, or only one grip means, relative to the other one which remains fixed with respect to the frame.

According to an additional aspect, a first and a second contact and cutting plate are -provided for the stack of sheets associated to the first and respectively to the second grip means whose mutual distance can be adjusted manually or with actuators which can be automatic, pneumatic or hydraulic or otherwise motorized, in order to work still closer to the cutting line.

Moreover, for large productions said plates can be shaped according to the shape of the blank or to the shape of the cutting line being processed.

The above mentioned adjustment mechanisms and contact and cutting plates are advantageously and preferably embodied in combination to the above described bundle breakers; it should not be excluded, however, that they be arranged in combination to one another or individually also with different kinds of bundle breakers. According to an additional aspect, the invention relates to a method for separating or cutting a stack of sheets comprising transverse and superposed cutting lines, characterized in that it comprises the following steps:

> feeding the stack of sheets on a first support according to a feed direction and subsequently on a second support flanked and distanced from the first support; > compacting or blocking the stack of sheets on the first and on the second support through first grip means and respectively second grip means, in such a way that one of the cutting lines is positioned between the first support and the second support and between the first grip means and the second grip means;

> vertically moving the second support together with the second grip means to break the cutting line positioned between the aforesaid first and second elements, i.e. perpendicularly to the direction of feeding of the stack of sheets;

> moving reciprocatingly in transverse direction relative to the direction of advance of the stack of sheets the second support together with the related second grip means;

> making the stack of sheets advance to break transverse cutting lines in succession.

In particular, the step of actuating in a transverse direction the second support together with the related second grip means can be accomplished simultaneously or in succession to the step of vertically actuating said supports.

In a particularly advantageous embodiment of the present invention, the step of vertically actuating the second support together with the related second grip means can be accomplished with a scissors-like motion of said second movable elements, i.e. reciprocatingly actuating the ends thereof.

Nevertheless, it would be possible to accomplish the aforesaid vertical actuation step by vertically translating both the movable elements, i.e. actuating their ends simultaneously.

Additionally, a step may easily be included in which the second support together with the related second grip means is thrust forward along the direction of feeding of the stack of sheets.

This latter step can be activated simultaneously to the vertical actuation step described above, in such a way as to accomplish a downwards and forwards cutting motion; or, this step can be activated in succession to one of the two aforesaid vertical actuation steps.

Clearly, said last forwards thrust step may be activated reciprocatingly to the vertical actuation step, in order to achieve the cut with a horizontal forward motion. According to a particularly advantageous embodiment of the invention, an initial step is provided to adjust the mutual distance between the first and the second support, and possibly also between the first and the second grip means, manually or via software.

This last step can comprise horizontally translating both the first and the second support, or both the first and the second grip means, in order to move them closer to or away from each other.

Alternatively, this last step can comprise translating horizontally one of the two supports, or one of the two grip means, in such a way as to approach it or distance it from the other.

Additionally, a further initial step can be provided to adjust the distance between first and second lower contact and cut plates for the stack of sheets associated in a movable manner to said first and second grip means.

An advantage of a machine according to the present invention is that it allows to cut and to free in succession and automatically contoured blanks that present cutting lines with undercut tabs or teeth, with no need for the intervention of an operator or of

additional devices in the work chain.

Another advantage is that it is possible to work in a simple and fast manner higher stacks of sheets, i.e. stacks with a greater number of stacked sheets, in particular providing for the aforesaid scissors-like cutting motion; for example, in the case of corrugated cardboard, it is possible to work stacks of sheets that presents twice or even three times the height of traditional pivotal cutting machines.

In this way, the yield of the machine is considerably increased and production costs are lowered.

Additionally, another advantage is that it is possible to work on contoured blanks used to obtain containers or boxes having different heights, i.e. blanks that present transverse cutting lines variously distanced on the sheet.

Yet another advantage is that it is possible to make countless adjustments for the cutting step according to the specific work process and in particular to the contour of the blank to be worked and to the shape of the cutting line; specifically, it is possible to adjust the distance between the supports and/or between the cutting means or to adjust the distance or to replace the contact plates or to combine different cutting motions, considerably reducing the possibility of defects, flaws or damages in the finished product. hi sum, the machine according to the invention is extremely versatile and fast and at the same time simple in its construction and use; the finished product also is of a high quality.

Additional advantageous characteristics and embodiments of the machine and of the method according to the present invention are indicated in the accompanying dependent claims and they shall be further described hereafter with reference to some non limiting examples of embodiment .

Brief description of the drawings

The present invention can be better understood and its numerous objects and advantages shall be readily apparent to those skilled in the art with reference to the accompanying schematic drawings, which show a practical non limiting example of the invention. hi the drawing:

Figure 1 shows an axonometric view of a machine according to an embodiment of the invention; figure 2 shows a section according to the line II-II of figure 3;

figure 3 shows a section according to the line 111-111 of figure 2; Figure 4 shows a partially sectioned lateral view of another embodiment of the invention; figure 5 shows a partially sectioned top view according to the line V-V of figure 4; figure 6 shows an enlarged detail of figure 4; figures 7A through 7H schematically show consecutive work steps of the machine of figure 1; figures 8 and 9 show two work steps, successive and alternative to that of figure 7C; figure 10 shows a section according to the line X-X of figures 12A and 12B of a different embodiment of the invention; figure 11 shows a front view of the embodiment of figure 10; figures 12A and 12B show a section according to, the line XIIA-XIIA and respectively XIIB-XIIB of figure 10; figure 13A shows a detail of another embodiment of the invention; figure 13B shows a cross section of figure 13 A.

Detailed description of some preferred embodiments of the invention In the drawings, in which to equal numbers correspond equal parts in all the different figures, a bundle breaker 1, see figures 1 through 3, comprises a fixed frame 2, a first support 3, a second support 5, a first grip means 7 and a second grip means 9 associated to each support 3 and 5; a stack P of sheets slides on the first support 3 and subsequently on the second support 5.

In the embodiment shown in this figure, the frame 2 comprises two pairs of vertical uprights 2A joined by two cross members 2B and by horizontal spacers 2C.

The first support 3 comprises a first pair of vertical and distanced plates or bulkheads 3P, see figure 2, anchored to the ends of a first lower supporting cross member 3 C, transverse relative to the direction of advance of the stack P of sheets; the ends of the cross member 3C pass through these plates 3P to be anchored in turn to the respective upright 2A of the frame 2.

Between the first plates 3P is mounted a plurality of transverse transmission rollers 15 which form a closed path for a conveyor belt 3A, whereon is placed the stack P of sheets and which is actuated by an electric motor 19, see figure 2, anchored on the same plates 3P.

In this configuration, the first support 3 and the supporting cross member 3 C, comprising the plates 3P and the related rollers 15, are fixed relative to the frame 2.

In the same manner, the second support 5 comprises a second pair of vertical and distanced plates or bulkheads 5P, see figures 2 and 3, between which are mounted a plurality of transverse transmission rollers 17 which form a second closed path for a second conveyor belt 5 A, whereon is pushed the stack P of sheets coming from the first conveyor belt 3A; this second belt 5A is actuated by a second electric motor 21, see figure 2, anchored on the same plates 5P.

It should be noted that the sliding belts 3 A and 5A are coplanar in the upper segment and distanced by a distance "D", see figures 4 through 6, in such a way as to form a feeding path or plane for the stack P of sheets that slides thereon. Differently from what is described for the first support 3, the second pair of vertical plates 5P is fastened to the ends of a first lower and transverse section bar 24, see figures 1 through 3, which in turn is connected in a movable manner on a second lower support cross member 5C, transverse with respect to the direction of advance of the stack P of sheets. The first lower section bar 24 presents substantially an inverse U shape and it is positioned above the second cross member 5C; the ends of the cross member 5C pass through the plates 5P to be anchored in turn to the respective upright 2A of the frame 2.

In this case, therefore, the second lower cross member 5 C is fixed relative to the frame 2 whilst the section bar 24 and the second support 5, comprising the related plates 5P and the related rollers 17, are movable relative to the support 5 C, see the description below.

Both the conveyor belts 3A and 5A follow a roughly triangular path formed by the transmission rollers 15 and respectively 17 in the number of three, however clearly a different path could be obtained with a different number of transmission rollers, and it cannot be excluded that the same supports 3 and 5 could be obtained in a different manner, e.g. replacing the system comprising the conveyor belts 3 A and 5 A with a system that uses a plurality of flat belts or table-top chains or chains with resin belt for accumulation or others yet.

Figures 2 and 3 show in particular a pair of first lower actuators 23A and 23B in vertical direction, a second lower actuator 27 in transverse direction and a pair of additional lower actuators 25A and 25B in horizontal direction; these lower actuators 23A, 23B; 25A, 25B and 27 are advantageously and preferably obtained with double acting pistons or jacks of the hydraulic or pneumatic type able to move the second support 5 relative to the second cross member 5C.

The aforesaid pairs of jacks are connected to the fixed frame 2 of the machine with respective mechanisms, described in detail below.

The pair of first lower actuators 23A and 23B is obtained with a first right jack and respectively a first left jack in vertical direction passing through openings of the second cross member 5C, their lower ends project from the same cross member 5C to be connected with respective couplings 23T, see in particular figure 3, by means of ball joints 23N; the upper ends project from the cross member 5C to be connected to the section bar 24 by means of additional ball joints 23M. The couplings 23T are fastened on the second cross member 5C and they project outwards substantially to create the space necessary for the positioning of the jacks 23A, 23B.

The purpose of these first jacks 23 A and 23B is to move vertically according to the arrows F2 and F4 - see description below in reference to figures 7C and 7F - i.e. in a plane perpendicular to the surface of advance of the stack P of sheets, the second support 5 with the second bulkheads 5P and the conveyor belt 5A. The pair of additional actuators 25A and 25B is obtained with a right jack and respectively a left jack in horizontal direction passing through the second cross member 5C, only the jack 25A is visible in figure 2; one end of these jacks 25A and 25B is connected to the cross member 5C by means of respective ball joints 25N, whilst the opposite end passes through openings of the cross member 5C to be connected to couplings 25T fastened on the section bar 24 by means of additional ball joints 25M.

These additional jacks 25A and 25B move forwards, i.e. in the direction of advance of the stack P of sheets - see arrow FA of figure 1 - the second support 5 comprising the second bulkheads 5P and the conveyor belt 5 A.

The second actuator 27 is obtained with a double acting jack positioned within the cross member 5C in transverse direction; one end of this jack 27 is connected to the same cross member 5C by means of a ball joint 27N, see figure 3. and the other end is connected to a coupling 27T by means of an additional ball joint 27M; the coupling 27T is free to slide in a slit of the cross member 5C to be fastened on the section bar 24.

This second jack 27 reciprocatingly moves in transverse direction relative to the direction of advance of the stack P of sheets - see the arrow F3 of figures 7D and 7E - the second support 7E with the second bulkheads 5P and the conveyor belt 5A.

It should be noted that the motion of the section bar 24 takes place by activating the jack 27 or the pair of jacks 23A - 23B or the pair of double acting jacks 25A - 25B. In any case, it could be possible to activate two or more of said jacks simultaneously, as

described above.

Above each support 3 and 5 are positioned the first and the second grip means 7 and 9 arranged side by side and mutually distanced according to the direction of advance of the stack P of sheets. In particular, figure 2 shows the first support means 7 which comprises a first upper support cross member 7C, transverse relative to the direction of advance of the stack P of sheets, whereon is fastened a first contact and cut plane 7A for the stack P of sheets.

The second grip means 9 comprises a second upper support cross member 9C transverse relative to the direction of advance of the stack P of sheets. Upper plate end stops 31 A and 3 IB connect the first and the second cross member 7C and respectively 9C - only the end stop 31A is shown in figure 2 whilst both are shown in figure 3 - and they each present an upper coupling 3 IT for a main actuator 32A and respectively 32B.

These main actuators 32A and 32B, too, are advantageously obtained with a double acting piston or jack of the hydraulic or pneumatic type.

Each main actuator 32A and 32B presents an upper end fastened to the corresponding upper coupling 3 IT by means of a respective rotary connecting joint 7M and a lower end fastened to the frame 2 by means of a corresponding rotary connecting joint 32M. The main actuators 32A and 32B move vertically - according to the arrows Fl, F5 of figures 7B, 7G - the first and the second grip means 7 and respectively 9 in such a way as to compact and secure (or, conversely, release) the stack P of sheets on the same supports 3 and 5.

On the cross member 9C of the second grip means 9 is movably fastened an upper, transverse section bar 34 which presents substantially U shape oriented upwards; on the lower surface of this section bar 34 is fastened a second contact and cut plate 9A for the stack P of sheets.

The section bar 34 moves relative to the second upper cross member 9C - similarly to what is already described for the lower support 5 - by means of a pair of first upper actuators 33A and 33B in vertical direction, see in particular figures 2 and 3, of a second upper actuators 37 in transverse direction and a pair of additional upper actuators 35A and 35B in horizontal direction; these upper actuators 33A, 33B and 35A, 35B and 37 are also advantageously and preferably obtained with double acting pistons or jacks of the hydraulic or pneumatic type.

The aforesaid pairs of actuators or jacks are connected to the second cross member 9C with respective mechanisms, described in detail below.

The pair of first upper actuators 33 A and 33B is obtained with a first right jack and respectively a first left jack in vertical direction passing through openings of the second cross member 9C, their ends project from the same cross member 9C to be connected with respective couplings 33T by means of ball joints 33N; the opposite ends project from the cross member 9C to be connected to the section bar 34 by means of additional ball joints 33M. The couplings 33T are fastened on the second cross member 9C and they project outwards substantially to create the space necessary for the positioning of the jacks 33 A, 33B.

These first jacks 33A and 33B move vertically i.e. in a plane perpendicular to the direction of advance of the stack P of sheets - see arrows F2 and F4 of figures 7C e 7F - the upper section bar 34 relative to the second cross member 9C and they are activated simultaneously to the first lower jacks 23 A and respectively 23B of the second support 5.

The pair of additional upper actuators 35A and 35B is obtained with a right jack and respectively a left jack in horizontal direction comprising a respective end connected to the cross member 9C by means of respective ball joints 35N - only the end stop 31A is shown in figure 2 whilst both are shown in figure 3 - and the other end passing through openings of the cross member 9C to connect to couplings 35T fixed on the section bar 34 by means of additional ball joints 35M, see also figure 1.

These additional jacks 35 A and 35B move in the direction of advance of the stack P of sheets — see arrow FA of figure 1 — the upper section bar 34 relative to the second cross member 9C and they are activated simultaneously to the additional lower jacks 25A and respectively 25B of the second support 5.

The second upper actuator 37 is obtained with a double acting jack positioned within the cross member 9C in transverse direction. One end of this second actuator 37 is connected to the same cross member 9C by means of a ball joint 37N, see figure 3, and the other end is connected to a coupling 37T by means of an additional ball joint 37M; the coupling 37T is free to slide through a slit of the cross member 9C in order to be fastened on the section bar 34.

This second jack 37 reciprocatingly moves in transverse direction relative to the direction of advance of the stack P of sheets - see the arrow F3 with reference to figures 7D and 7E - the upper section bar 34 relative to the second cross member 9C and it is

activated simultaneously to the second lower jack 27 of the second support 5.

It should be noted that the motion of the upper section bar 34 relative to the cross member 9C takes place simultaneously with that of the lower section bar 24 by activating the second upper and lower jack 37 and respectively 27 or the pair of upper and lower jacks 33 A, 33B and respectively 23 A, 23B or the pair of additional upper and lower jacks 35A, 35B and respectively 25 A, 25B double acting.

Moreover, a sensor 4 of the type with feeler or photoelectric cell is used to detect when a transverse cutting line T is between the first and the second support 3 and 5 in such a way as to block the advance of the stack P of sheets. Figures 4 and 5 show an adjustment mechanism to adjust the mutual distance "D" between the first and second support 3 and 5; this mechanism is not shown in the previous figures for the sake of simplicity.

Ih particular, this adjustment mechanism comprises an activator 41, e.g. an electric motor or a crank, mounted on the first support 3 in lateral position and connected through a reduction gear 43 to a driving worm screw 45, which in turn is connected to a driven worm screw 47 through a connecting joint 49.

The driving screw 45 is free to rotate at one end on an "L" shaped bracket 45A fastened on the frame 2 and it meshes with a lead nut 49B fastened on the first lower support cross member 3 C; similarly, the driven screw 47 is free to rotate on an "L" shaped bracket 47A fastened to the frame 2 and meshing with a lead nut 45B fastened on the second lower support cross member 5C.

The ends of the first cross member 3C and of the second cross member 5C slide on a first and a second pair of horizontal prismatic guides 51 and respectively 53 fixed on the frame 2. The aforesaid worm screw 45 and 47 have opposite threads so that, when activated to rotate by the motor 41, they enable mutually to approach and distance the two supports 3 and 5.

Figure 5 is a top view showing two substantially similar adjustment mechanisms positioned on each side of the frame 2; a transmission system transmits motion to the corresponding driven screw 47 on the opposite side of the frame 2, e.g. a chain transmission system 55.

With the arrangement described above, the operator can set the distance "D" whereat the first and the second support 3 and 5 have to be positioned through a command on the control panel, mainly as a function of the shape of the cutting line and of the

distance of successive cutting lines.

Clearly, the motion may be imparted to the driving screw 45 by means of other devices, e.g. cranks which can be operated manually or others.

The distance between the first and the second upper grip means can be adjustable by means of an adjustment mechanism similar to what is described above.

In this way it is possible to optimize the cutting step enormously, increasing the operating speed of the machine and the quality of the finished product. Figure 6 is an enlarged detail of figure 4, showing a transmission roller 15 positioned between the vertical plates 3P of the support 3 and a transmission roller 17 positioned between the vertical plates 5P of the support 5 distanced by the distance "D" and in proximity to which are mounted respective transverse cutting abutments or transverse stationary blades 59 and 60, rigid and replaceable obtained, in this embodiment, with respective upside down "L" bars which define the cutting lines more precisely, in order further to improve the cut itself. In particular, the stationary blade 59 is fastened on the vertical plates 3P of the fixed support 3 through a vertical screw 59B adjustable in supports 59A fastened on each vertical plate 3P; in a similar manner, the stationary blade 60 is fastened on the vertical plate 5P of the movable support 5 through a vertical screw 6OB adjustable in supports 6OA fastened on each vertical plate 5P. In this way it is possible to adjust the height of said stationary blade 59 and 60 manually relative to the plane of sliding of the stack P of sheets by appropriately rotating the respective threaded screws 59B and 6OB, avoiding the formation of a step which may block the sliding of the stack P of sheets; it is also possible to replace the stationary blades 59 and 60 with stationary blades having the appropriate shape, according to the shape of the cutting line T of the specific work process.

It should be noted that the stationary blades 59 and 60 can be provided also on a bundle breaker of a different kind, depending upon special constructional or use requirements.

Figures 7A-7H schematically show consecutive working steps of the machine described above.

In particular, figure 7A shows a step in which stack of die cut sheets P is fed on the first support 3 according to a direction of feeding FA and subsequently on the second support 5 flanking, and distanced fiom, the first support 3. The advance of the stack P of sheets is blocked when a transverse cutting line T is between the first and the second

support 3 and 5 by. means of the detection of a sensor 4 of the type with feeler pin or photoelectric cell, see figures 2 and 3, in a manner that is substantially known to those skilled in the art.

In this step the first and the second upper grip means 7 and respectively 9 are completely raised so that the lower plates TA and 9A are not in contact with the stack P of sheets.

Figure TB shows a subsequent step in which the stack P of sheets is compacted or blocked on the first and on the second support 3 and 5 by lowering the first and the second grip means 7 and respectively 9 through the activation of the main actuators 32 A and 32B - see arrow Fl - the lower plates 7A and 9A press on the stack P of sheets.

Figure 7C shows a subsequent step in which the second support 5 together with the related second grip means 9 are actuated downwards - see arrow F2 - by the activation of the first lower and upper jacks 23A, 23B and respectively 33A, 33B to cut perpendicularly to the direction of feeding the stack P of sheets along the cutting line T positioned between the aforesaid first and second elements.

This vertical motion is achieved by vertically translating both movable elements 5 and 9, i.e. simultaneously moving their ends; this motion is in the order of some tens of centimeters, specifically from about 2 centimeters (cm) to about 50 (cm) and more, depending on the height of the stack P of sheets and on the material being worked. Figure 7D shows a subsequent step in which the second support 5 together with the related second grip means 9 is translated reciprocatingly in transverse direction - see arrow F3 - relative to the direction of advance of the stack P of sheets, by means of the second lower and upper jack 27 and respectively 37, in order to detach or free the stack of cut blanks from the adjacent stack of blanks, see description below; this transverse motion is in the order of some centimeters, specifically from about 1 (cm) to about 5 (cm) or more.

In this step, it is readily apparent that the first lower and upper jacks 23 A, 23B and respectively 33A, 33B are deactivated and inclined in the direction of the transverse motion thanks to the ball joints 23M, 23N and respectively 33N, 33M; the additional lower and upper actuators 25A, 25B and respectively 35A, 35B, not shown in the figure for the sake of simplicity, are also deactivated and inclined.

Figure 7E shows from the top the transverse motion described in figure 7D in which the superposed sheets of the stack P comprise transverse cutting lines T distanced at regular intervals to form successive stacks of contoured blanks Sl, S2 and S3; on each

cutting line T is obtained an undercut tab or tooth L which, projects transversely relative to the direction of advance of the stack P of sheets.

As is readily apparent from this figure, the contoured blank Sl is detached from the next blank S2 freeing the tooth S thanks to the transverse motion according to the arrow F3 described above.

Figure 7F shows a subsequent step in which the second support 5 together with the related second grip means 9 are translated upwards - see arrow F4 - by the activation of the first lower and upper jacks 23 A, 23B and respectively 33 A, 33B in such a way as to return the stack P of sheets on the feeding plane. Figure 7G shows a subsequent step in which the stack P of sheets is released by lifting the first and the second grip means 7 and 9 - see arrow F5 - through the activation of the main actuators 32A and 32B in order to advance - figure 7H - the stack P of cut blanks towards the output of the bundle breaker 1 and to advance a subsequent stack P of sheets to be detached. Figures 8 and 9 show two successive work sub-steps that are alternative to that of figure 7C in which the downward actuation step is achieved with an inclined, i.e. scissors-like, motion of the second support 5 together with the related second grip means 9.

In a first sub-step, see figure 8, the first left lower and upper jacks 23A and respectively 33A are activated to move downwards - see arrow F2A - whilst the first right lower and upper jacks 23B and 33B are inactive and rotate around the ball joints 23M, 23N and respectively 33N, 33M - see arrows M2A - to incline in a scissors-like manner the second support 5 together with the related second grip means 9.

In a second sub-step, see figure 9, the first right lower and upper jacks 23B and respectively 33B are activated to move downwards - see arrow F2B - whilst the first left lower and upper jacks 23A and 33A are inactive and rotate around the ball joints 23M, 23N and respectively 33N, 33M - see arrows M2B - to return the second support 5 together with the related second grip means 9 in horizontal configuration and to complete the cutting of the stack P of sheets. This scissors-like movement is of the same extension as the vertical translation described above with reference to figure 7C.

Additionally, a step may easily be included, not shown in the figures for the sake of simplicity, in which the second support 5 together with the related second grip means 9 is thrust along the direction of feeding of the stack P of sheets by the activation of the additional lower and upper actuators 25 A and respectively 35 A.

This forward motion step can be activated simultaneously to the aforesaid vertical actuation step, in order to accomplish a cutting motion that is inclined downwards and forwards; this forward motion step can also be activated in succession to the aforesaid downward motion step. Clearly, this last forwards motion step may be activated reciprocatingly to the downwards motion step, in order to achieve the cut with a horizontal forward motion.

Moreover, the forward motion step can also be achieved with an inclined, i.e. scissors-like, motion of the second support 5 together with the related second grip means 9, by appropriately activating respective j acks. According to a particularly advantageous embodiment of the invention, an initial step is provided to adjust the mutual distance between the first and the second support 3 and respectively 5, and possibly also between the first and the second grip means 7 and respectively 9, manually by acting on mechanical devices or automatically through controls via software. Figures 10 to 12B show a different embodiment of the invention comprising a first lower support 103 with a respective first upper grip means 107 and a second lower support 105 with a respective second upper grip means 109.

The second lower support 105 comprises lower bearing elements 105 S with substantially parallelepiped or box-like shape, see figures 11 and 12 A, slidable on respective lower horizontal prismatic guides 153 fastened laterally on the frame 2.

In this embodiment the box shaped elements 105 S substantially serve the same function as the second cross member 5C described in the previous embodiment, i.e. to provide a support and to guide the movable elements of the machine.

Ends of a first lower cross member 124A are hinged both to the box shaped elements 105 S by means of rotation bars 125N, see figure 11, and to a second actuator 121, see figure 12A, e.g. a double acting jack, which moves the first cross member 124A reciprocatingly in transverse direction relative to the direction of advance of the stack P of sheets, see the arrow F3 with reference to figures 7D and 7E.

This second actuator 121, see figure 12A again, is hinged at one end to one of the two box shaped elements 105S by means of a rotary joint 121N and at the other end to the first lower cross member 124A by means of a rotary joint 121M.

A second lower cross member 124B, see figures 10 and 11, is positioned above the first cross member 124 A and comprises plates 105P whereon are positioned

' transmission rollers 170 that form a path for the conveyor belt 5 A of the second lower

support 105.

Pairs of "L" shaped lower couplings 123H are provided, passing in slots obtained in the first cross members 124A and hinged at one end to a double acting jack 123A and respectively 123B by means of a respective rotary joint or articulation 123N, at the opposite end hinged to the second cross member 124B by means of a respective rotary joint 123K and at the centre hinged on an extension 103P of the first cross member 124A by means of a rotary joint 123R.

The double acting jack 123A and respectively 123B is hinged to the first cross member 124A by means of a respective rotary joint 123M. Therefore, in this embodiment, the reciprocating motion in transverse direction of the second support 105 relative to the direction of advance of the stack P of sheets, see arrow F3 in reference to figures 7D and 7E, is achieved thanks to the second actuator 121, in this ύase a double acting jack, whilst the vertical cutting motion, see arrows F2 and F4 of figures 7C and 7F 5 is accomplished by the jacks 123A and 123B. The secorid upper grip means 109 comprises, similarly to the mechanism described above with reference to the second support 105, respective parallelepiped shaped bearing elements 109S, see figures 11 and 12B, slidable on respective upper horizontal prismatic guides 157 fastened laterally on the frame 2.

Ends of a first upper cross member 134A are hinged both to the box shaped elements 109S by means of rotation bars 135N and to a second actuator 131, see figure 12B, e.g. a double acting jack, which moves the first cross member 134A reciprocatingly in transverse direction, simultaneously to the motion of the first cross member 124A achieved with the second lower actuator 121.

This second upper actuator 131 is hinged at one end to one of the two box shaped elements 109S by means of a rotary joint 131N, see figure 12B, and at the other end to the first cross member 134A by means of a rotary joint 13 IM.

A second lower cross member 134B, see figures 10 and 11, is positioned above the lower cross member 134A and it comprises the second plate 9A which serves as a contact and cutting surface for the stack P of sheets. In this case, too, there are pairs of "L" shaped couplings 133H passing in slots obtained in the first cross member 134A and hinged at one end to a double acting jack 133A and respectively 133B, see figures 11 and 12B, by means of a respective rotary joint or articulation 133N, at the other end hinged to the second cross member 134B by means of a respective rotary joint 133K and at the centre hinged on an extension 133P

of the first cross member 134A by means of a rotary joint 133R.

The double acting jack 133 A and respectively 133B is hinged to the first cross member 134A by means of a respective rotary joint 133M.

Therefore, the reciprocating motion in transverse direction, see the arrow F3 of figures 7D and 7E, of the second upper grip means 109 takes place by means of the second upper actuator 131 and the vertical cutting motion, see the arrows F2 and F4 of figures 7C and 7F 5 is achieved by the jacks 133 A and 133B; these motions take place simultaneously to. the respective motions of the second support 105.

It should be noted that in this embodiment the lower rotary joints 123N, 123K, 123R, 123M and the upper ones 133N, 133K, 133R, 133M.are of the cylindrical hinge type, unlike the ball joints 23N, 23M, 25N, 25M, 27N and 27M described in the previous embodiment, which are of the spherical hinge type.

In this embodiment, too, it is possible to adjust the distance between the first and the second lower support 103 and respectively 105 through a mechanism that comprises a lower screw 151, see figure 12A, on each side of the frame 2.

Each lower screw 151 meshes with a respective lead nut 15 IB fixed on each box shaped element 105 S; these screws 151 are set in rotation by a motor 15 IM by means of a transverse chain 151 C and a related sprocket.

Therefore, the distance between the first and the second support 103 and respectively 105 is adjusted by means of a command imparted to the motor 15 IM up to even 10 (cm) or more; instead, the possible forwards cutting motion of the second support 105 relative to the first support 103 takes place by means of the actuators 161 up to about 1

(cm) or slightly more.

A similar adjustment mechanism is provided to adjust the distance between the first and the second upper grip means 107 and respectively 109 comprising a screw 171, see figure 12B, on each side of the frame 2 that meshes with a respective lead nut 171B fixed on the second grip means 109; these screws 171 are set in rotation by a motor

171M by means of a transverse chain 171C. Therefore, the distance between the first and the second grip means 107 and respectively 109 is adjusted by means of a command imparted to the motor 171M; instead, the possible forwards cutting motion of the second support 109 relative to the first support 107 takes place by means of the actuators 162.

Figures 13 A and 13B show the first plate 7A and the second plate 9A of the grip means 7 and respectively 9; the cutting line of the stack P of sheets to be cut stops

between these plates 7A and 9 A. In this embodiment each of these plates 7A and 9A comprises three movable and replaceable boards 10 fastened inferiorly to the first and to the second grip means 7 and respectively 9 by means of a manual engagement device. This engagement device enables to move the boards 10 in such a way as to adjust them manually as close as possible to the cutting line 7 and it consists of a plurality of knobs 1OA mounted distanced on an edge 7B and respectively 9B of each grip means 7 figure 13B, which is screwed in a guiding bushing 1OB fixed on the edge 7B or 9B - figure 12B shows only an enlargement of the area of the edge 7B for the sake of simplicity - and to a lead nut 1OC. On the lead nut 1OC is fastened a transverse square 1OS whereon is screwed the end of the board 10 by means of locking screws 1 OF.

The longitudinal ends of each board 10 slide in double "T" shaped support guides 1OU that are locked on the lower surface of the respective grip means 7 or 9 by means of locking screws 1OZ.

Therefore, by acting on the knobs 1OA the boards 10 can be moved by some centimeters relative to the grip means 7 or 9 adjusting their position relative to the cutting line T.

Instead, acting on the locking screws 1OF and 1OZ it is possible to replace the same boards 10.

One cannot exclude the possibility of using boards 10 contoured in such a way as to adapt to the shape of the blanks Sl -S3 or of the cutting lines T being processed, to work as close as possible to the breaking point, improving the cut and lowering the probability of producing machining flaws.

It is clear that the engagement device described above is purely indicative, since this device can be of any other convenient type. It should be noted that the aforesaid adjustable and replaceable boards 10 find a particularly advantageous application for large scale productions and in combination with the stationary blades 59 and 60 and possibly with the system for adjusting the distance of the supports 3 and 5 and/or of the grip means 7 and 9 described above, since a still more advanced optimization of the cutting step is obtained, further increasing the operating speed of the machine and the quality of the finished product.

It is understood that what is illustrated herein represents only some non limiting embodiments of the invention, which can vary in the forms and arrangements without departing from the scope of the concept of the invention. The presence of any reference number in the appended claims has the sole purpose of facilitating reading in light of the

above description and of the accompanying drawings and it in no way limits the scope of protection.