A SYSTEM WITH AN INTERFOLDING MACHINE, A METHOD AND AN INTERFOLDING MACHINE

Abstract

A system comprising an interfolding machine with a frame and an interfolding unit comprising a set of roller units removably housed and independent of one another in seats of the frame, a second set of roller units, interchangeable with the set and couplers for coupling to one another respectively the roller units of the set and of the second set. Each roller unit comprises a first part and a second part and a rotatable roller. Both the couplers comprise a structure and connecting means for connecting the first part and the second part of each roller unit to the respective structure and are configured to keep the first and second parts in the positions in which they engage the frame. A method for the cut-off change and an interfolding machine.

Description

FIELD OF THE INVENTION

The present invention relates to the technical sector regarding the production of interfolded packs of sheet articles. In this technical sector, interfolding machines are normally used that ensure the formation of interfolded packs of sheet articles obtained by cutting or perforating continuous strips, usually originating from the unwinding of reels. In greater detail, the present invention concerns a system and a method which enable a rapid and easy replacement of the roller units of an interfolding machine in such a way as to operate the interfolding machine with different lengths of the sheet articles, a characteristic commonly known as cut-off.

The advantages of the use of interfolded packs produced with interfolding machines such as, for example, the one described in EP 2437994 B1, are known.

In like interfolding machines, as with the one illustrated in FIG. 1 or FIG. 5, before or during the unwinding and folding of the strips, cuts or lines or pre-cut perforations or tear lines are realised to produce sheet articles. These are moved by a roller, termed a folding roller, and folded by folding elements, visible in FIG. 4, which collect them from the folding roller and interpose them with the sheet articles coming from the opposite side and folded by other folding elements, also illustrated in FIG. 4. Generally, the interfolding machines comprise an interfolding unit which comprises folding rollers, cutting rollers and folding elements or cutting and folding rollers and folding elements, with the rollers arranged opposite one another so as to operate on distinct strips from which the sheet articles are obtained, which are interfolded. The cutting rollers, or cutting and folding rollers, usually cooperate with blades or counter-blades fixed and arranged in proximity of the cutting rollers. Typically the folding roller, or cutting and folding roller, is provided with recesses and channels in which a depression is formed, so as to attract the sheet articles and take them into the area where the stack is formed.

The folding elements enter and exit from gullies made on the folding roller, detaching the sheet articles and creating the fold.

To obtain interfolded packs of good quality it is necessary for all the rollers and the folding elements to operate in a coordinated way; for this reason a step is included of regulating or adjustment of the reciprocal orientation of the rollers following the installation thereof or, possibly, following the changing of operating conditions, for example when the material of the sheet is changed. In general, after the regulating of the rollers, so that they are in phase with one another, the folding elements are regulated. These adjustments often include the intervention of an external technician.

The diameter of the rollers is determined by the desired length of the sheet articles; typically the circumference of the rollers must be a multiple of the desired length. It is therefore necessary to change the rollers each time it is required to work with a different length of the sheet articles.

DESCRIPTION OF THE PRIOR ART

In the known systems two solutions are known for the replacement of the rollers.

A first solution, illustrated for example in EP2437994B1, has each roller independent of the others, i.e. the interfolding machine comprises a housing for each roller. In the case of a cut-off change it is necessary to remove each roller singly, and remount each roller, regulate the reciprocal orientation of the rollers and, possibly, the position of the folding elements with respect to the orientation of the rollers.

In a second solution the interfolding machine comprises a frame with a removable part that bears the rollers. In the case of a cut-off change, the removable part has to be removed from the fixed part of the frame, as can be observed, for example, in EP1630118B1.

Neither solution is without drawbacks: the first solution enables a simple movement of the rollers and the possibility of easily changing single rollers, but requires a long replacement operation and the presence of an external technician; the second solution reduces the replacement operation times but complicates the replacement of the single rollers and requires an appropriate configuration of the frame and of the couplings between the frame and the rollers.

The present invention intends to obviate one or more drawbacks of the solutions of the prior art.

SUMMARY OF THE INVENTION

A first aim of the present invention is to provide a system which enables rapidly to replace the rollers of an interfolding machine so as to be able to operate with sheet articles having different lengths (cut-off).

A second aim is to make available a system in which it is not necessary to place the rollers in phase each time they are replaced so as to be able to operate with sheet articles having different lengths.

A further aim, especially of some embodiments, is to provide a system or an interfolding machine in which the replacement of the rollers is especially easy and rapid.

A further aim is to allow exploitation of the teachings of the invention in existing systems.

These and other aims, which will be obvious to the expert in the sector from a reading of the following text, are attained by means of a system for production of interfolded packs of sheet articles from strips, a method for varying the length of the sheet articles of the interfolded packs of sheet articles produced from strips in an interfolding machine and of an interfolding machine for production of interfolded packs of sheet articles from strips, according to the claims.

According to the teachings of the present document, the system comprises an interfolding machine for production of interfolded packs of sheet articles from strips which comprises a frame and an interfolding unit, for cutting sheet articles from strips and for arranging the sheet articles so as to realise interfolded packs.

The interfolding unit comprises a set of roller units, having a first roller unit and a second roller unit the rollers of which are configured for moving sheet articles, and folding elements cooperating with the first roller unit and the second roller unit in order to arrange the sheet articles in an interfolded way.

Each roller unit of the set comprises a first part, a second part and, between them, a roller which is rotatable with respect to the first part and to the second part about a respective rotation axis. The first part and the second part of a roller unit of the set are respectively distinct from the first part and the second part of another roller unit of the set. The frame comprises, for each roller unit of the set, a first seat which removably houses a respective first part and a second seat which removably houses a respective second part.

The system further comprises a second set of roller units which is interchangeable, in the interfolding machine, with the set and which comprises a third roller unit and a fourth roller unit interchangeable respectively with the first roller unit and the second roller unit so as to cooperate with the folding elements.

Each roller unit of the second set comprises a first part removably engageable with a respective seat of the first seats, a second part removably engageable with a respective seat of the second seats and, between them, a roller which is rotatable with respect to the first part and to the second part about a respective rotation axis. The first part and the second part of a roller unit of the second set are respectively distinct from the first part and the second part of another roller unit of the second set.

The rollers of the third roller unit and the fourth roller unit differ from the rollers of the first roller unit and of the second roller unit so as to operate with a different length of sheet articles.

The system advantageously comprises a first coupler for reciprocally coupling the roller units of the set and a second coupler for reciprocally coupling the roller units of the second set.

The first coupler comprises a structure which is configured to support the weight of the roller units of the set and connecting means for connecting the first part and the second part of each roller unit of the second set to the structure so as to be able to move the roller units of the set. Further, the first coupler is configured in such a way as to maintain the first parts and the second parts of the roller units of the set in the positions they reciprocally occupy when they engage the first seats and the second seats.

The second coupler comprises a second structure which is configured to support the weight of the roller units of the set and second connecting means for connecting the first part and the second part of each roller unit of the second set to the second structure so as to be able to move the roller units of the second set.

Further, the second coupler is configured in such a way as to maintain the first parts and the second parts of the roller units of the second set in the positions they reciprocally occupy when they engage the first seats and the second seats.

In accordance with the teachings of the present document, the method comprising steps of:

• • providing a system according to the invention;
  • replacing the set of roller units with the second set of roller units.

In the step of replacing the set of roller units, the roller units of the set are connected to the structure with the connecting means and the roller units of the second set are made to connect, or are already connected, to the second structure with the second connecting means.

In accordance with the teachings of the present document, the interfolding machine is configured so as to enable lifting together of the roller units together of the set.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments of the invention will be described in the following part of the present description, according to what is set down in the claims and with the aid of the accompanying figures, in which:

FIG. 1 is an axonometric view of an embodiment of a system according to the invention;

Figures from 2 to 4 illustrate a sequence of the steps for replacing the set of roller units;

FIG. 5 is a frontal view of a different embodiment of an interfolding machine of a system according to the invention;

FIG. 6 shows an axonometric view of the structure visible in FIGS. 1, 3 and 4;

FIG. 7 is a frontal view of a different embodiment of a set of roller units;

FIGS. 8 and 9 show a frontal view and a rear view of an interfolding machine without roller units;

FIG. 10 is an axonometric view from behind of the interfolding machine in the condition of FIG. 2;

FIG. 11 is an axonometric view alike to the view of FIG. 2 but with a second set of roller units and with some elements not included in order to better illustrate the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the appended figures, reference numeral 100 denotes a system.

The references are included to facilitate understanding of the invention but are not intended to limit the scope of protection thereof.

An embodiment of the system (100) comprises an interfolding machine (10) for production of interfolded packs of sheet articles from strips, usually obtained from the unwinding of reels, a second set of roller units (7a, 7b, 7c, 7d), a first coupler (50) and a second coupler (80).

The interfolding machine (10) comprises a frame (1) and an interfolding unit (2), for cutting sheet articles from strips and for arranging the sheet articles so as to realise interfolded packs.

The interfolding unit (2) comprises a set of roller units (3a, 3b, 3c, 3d), which include a first roller unit (3a) and a second roller unit (3b), and folding elements (4)

Each roller unit (3a, 3b, 3c, 3d) of the set comprises a first part (31a, 31b, 31c, 31d), a second part (32a, 32b, 32c, 32d) and, between them, a roller (33a, 33b, 33c, 33d) which is rotatable with respect to the first part (31a, 31b, 31c, 31d) and to the second part (32a, 32b, 32c, 32d) about a respective rotation axis (A, B, C, D).

The rollers (33a, 33b) of the first roller unit (3a) and the second roller unit (3b) are configured for moving sheet articles, and cooperate with the folding elements (4) to arrange the sheet articles in an interfolded way.

The first part (31a, 31b, 31c, 31d) and the second part (32a, 32b, 32c, 32d) of a roller unit (3a, 3b, 3c, 3d) of the set are respectively distinct from the first part (31a, 31b, 31c, 31d) and the second part (32a, 32b, 32c, 32d) of another roller unit (3a, 3b, 3c, 3d) of the set. In other words, each roller unit (3a, 3b, 3c, 3d) of the set is a single entity, i.e. singly removable from or insertable in the interfolding machine (10).

The frame (1) comprises, for each roller unit (3a, 3b, 3c, 3d) of the set, a first seat (14a, 14b, 14c, 14d) which removably houses a respective first part (31a, 31b, 31c, 31d) and a second seat (15a, 15b, 15c, 15d) which removably houses a respective second part (32a, 32b, 32c, 32d). In other words, the frame (1) comprises a first seat (14a, 14b, 14c, 14d) and a second seat (15a, 15b, 15c, 15d) for housing one of the roller units (3a, 3b, 3c, 3d) of the set. As visible in the accompanying figures, the first seats (14a, 14b, 14c, 14d) and the second seats (15a, 15b, 15c, 15d) insist on opposite sides of the frame (1).

The second set of roller units ((7a, 7b, 7c, 7d) is interchangeable, in the interfolding machine (10), which set comprises a third roller unit (7a) and a fourth roller unit (7b) interchangeable respectively with the first roller unit (3a) and the second roller unit (3b) so as to cooperate with the folding elements (4), once the set has been replaced with the second set.

For each roller unit (7a, 7b, 7c, 7d) of the second set comprises a first part (71a, 71b, 71c, 71d) removably engageable with a respective seat of the first seats (14a, 14b, 14c, 14d), a second part (72a, 72b, 72c, 72d) removably engageable with a respective seat of the second seats (15a, 15b, 15c, 15d) and, between them, a roller (73a, 73b, 73c, 73d) which is rotatable with respect to the first part (71a, 71b, 71c, 71d) and to the second part (72a, 72b, 72c, 72d) about a respective rotation axis (A′, B′, C′, D′). In the present description and in the drawings the letters relating to the set correspond to the letters relating to the second set due to the interchangeability thereof.

A first part (71a, 71b, 71c, 71d) and the second part (72a, 72b, 72c, 72d) of a roller unit (7a, 7b, 7c, 7d), of the second set are respectively distinct from the first part (71a, 71b, 71c, 71d) and the second part (72a, 72b, 72c, 72d) of another roller unit (7a, 7b, 7c, 7d) of the second set. In other words, each roller unit (7a, 7b, 7c, 7d) of the second set is a single entity, i.e. singly removable from or insertable in the interfolding machine (10).

The rollers (73a, 73b) of the third roller unit (7a) and of the fourth roller unit (7b) differ from the rollers (33a, 33b) of the first roller unit (3a) and of the second roller unit (3b) so as to operate with a different length of sheet articles; in general the rollers (73a, 73b, 73c, 73d) of the second set differ from the rollers (33a, 33b, 33c, 33d) of the set.

It is specified that in the accompanying figures it is not possible to observe the dimensional variations between the set and the second set as the diameters vary by small amounts.

The first coupler (50) is configured for reciprocally coupling the roller units (3a, 3b, 3c, 3d) of the set and the second coupler (80) in configured for reciprocally coupling the roller units (7a, 7b, 7c, 7d) of the second set.

The first coupler (50) comprises a structure (5) which is configured to support, i.e.

to support at least, the weight of the roller units (3a, 3b, 3c, 3d) of the set and connecting means (6) for connecting the first part (31a, 31b, 31c, 31d) and the second part (32a, 32b, 32c, 32d) of each roller unit (3a, 3b, 3c, 3d) of the set to the structure (5) so as to be able to move the roller units (3a, 3b, 3c, 3d) of the set together.

The first coupler (50) is configured in such a way as to maintain the first parts (31a, 31b, 31c, 31d) and the second parts (32a, 32b, 32c, 32d) of the roller units (3a, 3b, 3c, 3d) of the set in the positions they reciprocally occupy when they engage the first seats (14a, 14b, 14c, 14d) and the second seats (15a, 15b, 15c, 15d).

The second coupler (80) comprises a second structure (8) which is configured to support, i.e. to support at least, the weight of the roller units (7a, 7b, 7c, 7d) of the set and second connecting means (9) for connecting the first part (71a, 71b, 71c, 71d) and the second part (72a, 72b, 72c, 72d) of each roller unit (7a, 7b, 7c, 7d) of the second set to the second structure (8) so as to be able to move the roller units (7a, 7b, 7c, 7d) of the second set.

The second coupler (80) is configured in such a way as to maintain the first parts (71a, 71b, 71c, 71d) and the second parts (72a, 72b, 72c, 72d) of the roller units (7a, 7b, 7c, 7d) of the second set in the positions they reciprocally occupy when they engage the first seats (14a, 14b, 14c, 14d) and the second seats (15a, 15b, 15c, 15d).

The system (100) of the invention advantageously enables rapidly replacing the rollers (33a, 33b, 33c, 33d) of the interfolding machine (10) with other rollers (73a, 73b, 73c, 73d) configured for a different length of the sheet articles of the interfolded pack.

The roller units (3a, 3b, 3c, 3d) of the set can be comfortably moved in unison after they have been coupled to one another by the coupler (50) which also guarantees or facilitates the maintenance in phase, i.e. with the correct reciprocal orientation.

Further, the coupler (50) enables maintaining the arrangement of the roller units (3a, 3b, 3c, 3d) of the set so as to be able to successively reintroduce them into the interfolding machine (10) in the required position for the correction positioning in the first seats (14a, 14b, 14c, 14d) and in the second seats (15a, 15b, 15c, 15d).

Some embodiments can comprise means for maintaining the rollers (33a, 33b, 33c, 33d) in position so as to guarantee the maintenance in phase thereof.

Each of the roller units (3a, 3b, 3c, 3d) preferably comprises a gear (34a, 34b, 34c, 34d), in general solidly constrained or made solid to the respective roller (33a, 33b, 33c, 33d), which is rotatable in unison with the respective roller (33a, 33b, 33c, 33d). The gears (34a, 34b, 34c, 34d) are for example visible in FIG. 10. As can be observed in FIG. 10, the coupling of the gears (34a, 34b, 34c, 34d) guarantees keeping the phase correct even after the extraction from the interfolding machine (10). Clearly the coupling for the set illustrated in FIG. 10 ensures in the same way the maintaining of the second set in phase.

The advantages described are also valid for the second set and the second coupler (80). After the set and the second set have been regulated on the interfolding machine (10) once the cut-off can be changed whenever desired, rapidly and, generally, without new adjustments of the set or second set. The set or second set not used in the interfolding machine (10) can remain available, ready for use, connected to the respective coupler (50, 80). It is generally necessary to match only the folding elements (4) to the new dimensions of the rollers (33a, 33b, 33c, 33d, 73a, 73b, 73c, 73d), for example by acting on the position of the fulcrum about which they oscillate.

The above-described advantages can also be applied to existing systems, with no, or a small, impact on the interfolding unit (2). However in the existing systems it is necessary to modify the upper portion of the interfolding machine (10) in such a way as to be able to proceed to lifting the roller-coupler assembly, i.e. in such a way as to have sufficient space above the interfolding unit (2) for the passage of the roller-coupler assembly.

As is known, the folding elements (4) are movable with respect to the frame (10) in such a way as to move away from and towards the first roller (33a) or the second roller (33b). Further, they are usually connected to means (not illustrated) for transforming a rotary motion in input into an oscillating motion in output. The means can comprise an input shaft, which rotates in phase with the rollers (33a, 33b, 33c, 33d), moved by at least a motor (not illustrated).

The roller units (3a, 3b, 3c, 3d, 7a, 7b, 7c, 7d) preferably also comprise a cogged gear (34a, 34b, 34c, 34d) for receiving drive from the motor, typically via transmission means (not illustrated) which might comprise belts and/or cogged wheels.

The interfolding machine (10) is preferably configured in such a way as to enable lifting the roller units (3a, 3b, 3c, 3d) of the set together, generally including the roller units (7a, 7b, 7c, 7d), of the second set. It is usually preferable for the frame (1) to have a U-shaped configuration at the first seats (14a, 14b, 14c, 14d) and at the second seats (15a, 15b, 15c, 15d) with the second seats opening upwards, towards the open part of the U.

Commonly, though not necessarily, the interfolding machine (10) comprises idler rollers and/or drive rollers at a greater height than that of the interfolding unit (2); with the aim of enabling the lifting, the components can advantageously be arranged at a greater height or it is possible to make at least a part of the interfolding machine (10) movable. To avoid having to rotate the set or second set, when extracting from or inserting in the first seats (14a, 14b, 14c, 14d) and the second seats (15a, 15b, 15c, 15d), the free space, or space freed with the movement of the movable part must be at least equal to the size in plan view of the roller units (3a, 3b, 3c, 3d) in the first seats (14a, 14b, 14c, 14d) and in the second seats (15a, 15b, 15c, 15d).

In this case too, like considerations are valid for the roller units of the second set (7a, 7b, 7c, 7d); the space is theoretically configured for the passage of the largest roller units-coupler assembly.

The lifting enables a rapid displacement, with the equipment typically available in industrial establishments, for example using bridge crane or a crane.

The frame (1) preferably comprises a first upper part (12) which bears idler rollers and/or drive rollers, a second upper part (13) which bears idler rollers and/or drive rollers and a lower part (11) which has the first seats (14a, 14b, 14c, 14d) and the second seats (15a, 15b, 15c, 15d). The first upper part (12) and the second upper part (13) are both movable with respect to the lower part (11) so as to free the space above the roller units (3a, 3b, 3c, 3d) necessary to enabling the lifting. A first example version of this is illustrated in FIG. 5, with the first upper part (12) and the second upper part (13) being able to translate with respect to the lower part (11) and which are moved by at least an actuator (16), in particular two. A second example version of this is illustrated in FIG. 4: the first upper part (12) and the second upper part (13) are both hinged to the lower part (11) the interfolding machine (10) comprises at least an actuator (16) which moves the first upper part (12) and the second upper part (13) between a first operating position and a second maintenance position in which the first upper part (12) and the second upper part (13) free the space above the roller units (3a, 3b, 3c, 3d) of the set so as to enable the lifting thereof.

The second version is particularly practical because it increases, in a limited way, or does not increase, the lateral volume of the interfolding machine (10).

In a preferred embodiment, the at least an actuator (16) comprises a first hydraulic or pneumatic cylinder (161) which is connected to the first upper part (12) and to the lower part (11) so as to move the first upper part (12) and a second hydraulic or pneumatic cylinder (162) which is connected to the second upper part (13) and to the lower part (11) so as to move the second upper part (13).

The connecting means (6) can comprise threaded connections or parts thereof, hydraulic gripping systems, such as, for example a hydraulic cylinder which moves coupling means, or other devices of known type.

For example the connecting means (6) can comprise screws and the structure (5) comprises openings (54) in which the screws engage, as visible in FIGS. 1 and 5. In greater detail, the first parts in the embodiments of the figures, the first parts (31a, 31b, 31c, 31d, 71a, 71b, 71c, 71d) and the second parts (32a, 32b, 32c, 32d, 72a, 72b, 72c, 72d) of the set and the second set comprise threaded holes in which screws fit which cross openings (54, 84) in the structure (5) and in the second structure (8).

Preferably, as in the represented embodiments, the structure (5) and the second structure (8) contact the respective first parts (31a, 31b, 31c, 31d, 71a, 71b, 71c, 71d) and the respective second parts (32a, 32b, 32c, 32d, 72a, 72b, 72c, 72d) when they are connected thereto; the correct repositioning is thus guaranteed also by the contact between the surfaces.

The interfolding unit (2) can comprise folding rollers and cutting rollers or cutting and folding rollers.

In a preferred embodiment the interfolding machine (10) comprises blades, or counter-blades, the set of roller units (3a, 3b, 3c, 3d) has two cutting roller units (3c, 3d) which cooperate with the blades, or counter-blades, to cut sheet articles from strips the structure (5) comprises a central part (51) which is configured to support the first parts (31a, 31b) and the second parts (32a, 32b) of the first roller unit (3a) and of the second roller unit (3b) and wings (52, 53) which project from the central part (51) on opposite sides and which are configured to support the first parts (31c, 31d) and the second parts (32c, 32d) of the two cutting roller units (3c, 3d). This can be seen, for example in FIG. 6. The wings (52, 53) enable collecting the roller units located at a higher level, i.e. the cutting roller units (3c, 3d), while the central part (51) can collect the first roller unit (3a) and the second roller unit (3b).

In this case too, like considerations are valid for the second structure (8), which can thus comprise a central part (81) and wings (82, 83), and for the second set which can have respective two cutting roller units (7c, 7d).

Owing to the characteristics illustrated above, the structure (5), or the second structure (8), can easily be brought into contact or near each roller unit (3a, 3b, 3c, 3d, 7a, 7b, 7c, 7d).

In another preferred embodiment the interfolding machine (10) comprises blades, or counter-blades, wherein and the first roller unit (3a) and the second roller unit (3b) cooperate with the blades, or counter-blades, for cutting sheet articles from strips.

In both the preferred versions, the blades, or counter-blades, are preferably fixed to the frame (1) by means of beams (20), one of which with the respective blade is visible in FIG. 11.

The first coupler (50) and the second coupler (80) or the structure (5) and the second structure (8) can be identical to one another or vary at most by the connecting means (6) or the second connecting means (9) or the openings (54, 84).

Preferably the structure (5), or the second structure (8), is grid-conformed so as to have a more rigid behaviour. An example of grid conformation is shown in FIG. 6.

Preferably the structure (5), or the second structure (8), comprises end parts that are opposite one another, longitudinal elements which connect them and rods that are oblique to the longitudinal direction which connect the longitudinal elements to one another.

More preferably, the end parts are connected to the set, or to the second set, by the respective connecting means (6, 9).

The invention also relates to a method for varying a length of sheet articles of interfolded packs of sheet articles produced from strips in an interfolding machine (10).

An embodiment of the method comprises steps of:

• • providing a system (100) according to the invention, i.e. as described in the foregoing;
  • replacing the set of roller units (3a, 3b, 3c, 3d) with the second set of roller units (7a, 7b, 7c, 7d).

Advantageously, in the step of replacing the set of roller units (3a, 3b, 3c, 3d), the roller units (3a, 3b, 3c, 3d) of the set are connected to the structure (5) with the connecting means (6) and the roller units (7a, 7b, 7c, 7d) of the second set are connected, or are already connected, to the second structure (8) with the second connecting means (9).

The presence of a first coupler (50) and a second coupler (80) enables replacing the roller units in a simple and rapid way, with the advantages already set out above with reference to the system (100).

After the step of replacing the set of roller units (3a, 3b, 3c, 3d) a step can be included of regulating the folding elements (4).

The method preferably comprises steps of:

• • adjusting the reciprocal orientation between the rollers (33a, 33b, 33c, 33d) of the set of roller units (3a, 3b, 3c, 3d) before the step of replacing the set of roller units (3a, 3b, 3c, 3d);
  • replacing the second set of roller units (7a, 7b, 7c, 7d) the set of roller units (3a, 3b, 3c, 3d) after the step of replacing the set of roller units (3a, 3b, 3c, 3d).

Further, between the step of replacing the set of roller units (3a, 3b, 3c, 3d) and replacing the second set of roller units (7a, 7b, 7c, 7d) the reciprocal orientation between the rollers (33a, 33b, 33c, 33d) of the set of roller units (3a, 3b, 3c, 3d) is maintained. In other words, the relation between the angular position of one of the rollers and the angular position of the other rollers (33a, 33b, 33c, 33d) with respect to the respective rotation axis (A′, B′, C′, D′) is maintained.

In the known systems the regulation is usually done or followed by an external technician; with the teachings of the invention it is no longer necessary to repeat this each time the set or second set is replaced. It is carried out once only, typically on installation and is not repeated, unless there is a change in operating conditions.

More preferably the method also comprises a step of:

• • adjusting the reciprocal orientation between the rollers (73a, 73b, 73c, 73d) of the second set of roller units (7a, 7b, 7c, 7d) after the step of replacing the set of roller units (3a, 3b, 3c, 3d).

In other words, the relation between the angular position of one of the rollers and the angular position of the other rollers (73a, 73b, 73c, 73d) with respect to the respective rotation axis (A′, B′, C′, D′) is maintained.

In this way the second set can also be subsequently extracted and re-introduced in the interfolding machine (10) with the advantages as discussed in the foregoing.

During the step of providing a system (100) a system (100) is provided which an interfolding machine (10) which preferably comprises a first upper part (12) which bears idler rollers and/or drive rollers, a second upper part (13) which bears idler rollers and/or drive rollers and a lower part (11) which has the first seats (14a, 14b, 14c, 14d) and the second seats (15a, 15b, 15c, 15d). The first upper part (12) and the second upper part (13) are both hinged to the lower part (11) and the interfolding machine (10) comprises at least an actuator (16) which moves the first upper part (12) and the second upper part (13) between a first operating position and a second maintenance position in which the first upper part (12) and the second upper part (13) free the space above the roller units (3a, 3b, 3c, 3d) of the set so as to enable the lifting thereof. In this case the method comprises a step of:

• • activating the at least an actuator (16) so as to bring the first upper part (12) and the second upper part (13) into the second maintenance position before the step of replacing the set of roller units (3a, 3b, 3c, 3d) or, possibly, before the step of replacing the second set.

The invention also relates to an interfolding machine (10) for production of interfolded packs of sheet articles from strips.

An embodiment of the interfolding machine (10) comprises a frame (1) and an interfolding unit (2), for cutting sheet articles from strips and for arranging the sheet articles so as to realise interfolded packs, which comprises: a set of roller units (3a, 3b, 3c, 3d), having a first roller unit (3a) and a second roller unit (3b) the rollers (33a, 33b) of which are configured for moving sheet articles, and folding elements (4) cooperating with the first roller unit (3a) and the second roller unit (3b) in order to arrange the sheet articles in an interfolded way.

Each roller unit (3a, 3b, 3c, 3d) of the set comprises a first part (31a, 31b, 31c, 31d), a second part (32a, 32b, 32c, 32d) and, between them, a roller (33a, 33b, 33c, 33d) which is rotatable with respect to the first part (31a, 31b, 31c, 31d) and to the second part (32a, 32b, 32c, 32d) about a respective rotation axis (A, B, C, D).

The first part (31a, 31b, 31c, 31d) and the second part (32a, 32b, 32c, 32d) of a roller unit (3a, 3b, 3c, 3d) of the set are respectively distinct from the first part (31a, 31b, 31c, 31d) and the second part (32a, 32b, 32c, 32d) of another roller unit (3a, 3b, 3c, 3d) of the set.

The frame (1) comprises, for each roller unit (3a, 3b, 3c, 3d) of the set, a first seat (14a, 14b, 14c, 14d) which removably houses a respective first part (31a, 31b, 31c, 31d) and a second seat (15a, 15b, 15c, 15d) which removably houses a respective second part (32a, 32b, 32c, 32d).

The interfolding machine (10) is advantageously configured in such a way as to enable lifting the roller units (3a, 3b, 3c, 3d) of the set together.

Preferred embodiments of the interfolding machine (10) are described in the foregoing in the description of the system (100). For example refer to the foregoing description for the movement modes of the first upper part (12) and the second upper part (13) or for the elements of the set of roller units (3a, 3b, 3c, 3d) and the mode of connection thereof to the frame (1) or for the configuration of the frame (1). The most relevant aspects are described briefly in the following.

The interfolding machine (10) preferably comprises blades, or counter-blades, wherein the set of roller units (3a, 3b, 3c, 3d) has two cutting roller units (3c, 3d) which cooperate with the blades, or counter-blades, for cutting sheet articles from strips. If follows that the interfolding machine (10) is configured in such a way as to enable lifting together of the first roller unit (3a), of the second roller unit (3b) and of the two cutting roller units (3c, 3d). As described above:

• • each roller unit (3a, 3b, 3c, 3d) of the set comprises a first part (31a, 31b, 31c, 31d), a second part (32a, 32b, 32c, 32d) and, between them, a roller (33a, 33b, 33c, 33d) which is rotatable with respect to the first part (31a, 31b, 31c, 31d) and to the second part (32a, 32b, 32c, 32d) about a respective rotation axis (A, B, C, D);

The first part (31a, 31b, 31c, 31d) and the second part (32a, 32b, 32c, 32d) of a roller unit (3a, 3b, 3c, 3d) of the set are respectively distinct from the first part (31a, 31b, 31c, 31d) and the second part (32a, 32b, 32c, 32d) of another roller unit (3a, 3b, 3c, 3d) of the set;

• • the frame (1) comprises, for each roller unit (3a, 3b, 3c, 3d) of the set, a first seat (14a, 14b, 14c, 14d) which removably houses a respective first part (31a, 31b, 31c, 31d) and a second seat (15a, 15b, 15c, 15d) which removably houses a respective second part (32a, 32b, 32c, 32d);

The frame (1) preferably has a U-shaped configuration at the first seats (14a, 14b, 14c, 14d) and at the second seats (15a, 15b, 15c, 15d) with the second seats opening upwards, towards the open part of the U.

It is understood that the above has been described by way of non-limiting example and that any constructional variants are considered to fall within the protective scope of the present technical solution, as claimed in the following.

Claims

1. A system comprising an interfolding machine for production of interfolded packs of sheet articles from strips which comprises a frame and an interfolding unit, for cutting sheet articles from strips and for arranging the sheet articles so as to realise interfolded packs, which comprises a set of roller units, having a first roller unit and a second roller unit the rollers of which are configured for moving sheet articles, and folding elements cooperating with the first roller unit and the second roller unit in order to arrange the sheet articles in an interfolded way, wherein: each roller unit of the set comprises a first part, a second part and, between them, a roller which is rotatable with respect to the first part and to the second part about a respective rotation axis;the first part and the second part of a roller unit of the set are distinct respectively from the first part and from the second part of another roller unit of the set;the frame comprises, for each roller unit of the set, a first seat which removably houses a respective first part and a second seat which removably houses a respective second part;the system comprises a second set of roller units which is interchangeable, in the interfolding machine, with the set and which comprises a third roller unit and a fourth roller unit interchangeable respectively with the first roller unit and the second roller unit so as to cooperate with the folding elements, each roller unit of the second set comprising a first part removably engageable with a respective seat of the first seats, a second part removably engageable with a respective seat of the second seats and, between them, a roller which is rotatable with respect to the first part and to the second part about a respective rotation axis and the first part and the second part of a roller unit of the second set being distinct respectively from the first part and from the second part of another roller unit of the second set;the rollers of the third roller unit and of the fourth roller unit differ from the rollers of the first roller unit and of the second roller unit so as to operate with a different length of sheet articles;the system being characterised in that it comprises a first coupler for reciprocally coupling the roller units of the set and a second coupler for reciprocally coupling the roller units of the second set, wherein:the first coupler comprises a structure which is configured to support the weight of the roller units of the set and connecting means for connecting the first part and the second part of each roller unit of the set to the structure so as to be able to move the roller units of the set together;the second coupler comprises a second structure which is configured to support the weight of the roller units of the second set and second connecting means for connecting the first part and the second part of each roller unit of the second set to the second structure so as to be able to move the roller units of the second set;the first coupler is configured in such a way as to maintain the first parts and the second parts of the roller units of the set in the positions they reciprocally occupy when they engage the first seats and the second seats;the second coupler is configured in such a way as to maintain the first parts and the second parts of the roller units of the second set in the positions they reciprocally occupy when they engage the first seats and the second seats.

2. The system of claim 1, wherein the interfolding machine is configured in such a way as to enable lifting the roller units of the set together.

3. The system of claim 2, wherein the frame comprises a first upper part which bears idler rollers and/or drive rollers, a second upper part which bears idler rollers and/or drive rollers and a lower part which has the first seats and the second seats, wherein the first upper part and the second upper part are both hinged to the lower part and wherein the interfolding machine comprises at least an actuator which moves the first upper part and the second upper part between a first operating position and a second maintenance position in which the first upper part and the second upper part free the space above the roller units of the set so as to enable the lifting thereof.

4. The system of claim 3, wherein the at least an actuator comprises a first hydraulic or pneumatic cylinder which is connected to the first upper part and to the lower part so as to move the first upper part and a second hydraulic or pneumatic cylinder which is connected to the second upper part and to the lower part so as to move the second upper part.

5. The system of claim 1, wherein the connecting means comprise screws and the structure comprises openings in which the screws engage.

6. The system of claim 1, wherein the interfolding machine comprises blades, or counter-blades, wherein the set of roller units has two cutting roller units which cooperate with the blades, or counter-blades, for cutting sheet articles from strips and wherein the structure comprises a central part which is configured to support the first parts and the second parts of the first roller unit and of the second roller unit and wings which project from the central part on opposite sides and which are configured to support the first parts and the second parts of the two cutting roller units.

7. The system of claim 1, wherein the interfolding machine comprises blades, or counter-blades, and wherein the first roller unit and the second roller unit cooperate with the blades, or counter-blades, for cutting sheet articles from strips.

8. A method for varying a length of sheet articles of interfolded packs of sheet articles produced from strips in an interfolding machine comprising steps of: providing a system according to claim 1;replacing the set of roller units with the second set of roller units;wherein in the step of replacing the set of roller units, the roller units of the set are connected to the structure with the connecting means and the roller units of the second set are connected, or are already connected, to the second structure with the second connecting means.

9. The method of claim 8, comprising steps of: adjusting the reciprocal orientation between the rollers of the set of roller units before the step of replacing the set of roller units;replacing the second set of roller units with the set of roller units after the step of replacing the set of roller units;wherein between the step of replacing the set of roller units and replacing the second set of roller units the reciprocal orientation between the rollers of the set of roller units is maintained.

10. The method of claim 8, wherein the frame comprises a first upper part which bears idler rollers and/or drive rollers, a second upper part which bears idler rollers and/or drive rollers and a lower part which has the first seats and the second seats, wherein the first upper part and the second upper part are both hinged to the lower part and wherein the interfolding machine comprises at least an actuator which moves the first upper part and the second upper part between a first operating position and a second maintenance position in which the first upper part and the second upper part free the space above the roller units of the set so as to enable the lifting thereof; wherein in the step of providing a system further comprises the step of:activating an actuator so as to bring the first upper part and the second upper part into the second maintenance position before the step of replacing the set of roller units.

11. An interfolding machine for the production of interfolded packs of sheet articles from strips which comprises a frame and an interfolding unit, for cutting sheet articles from strips and for arranging the sheet articles so as to realise interfolded packs, which comprises a set of roller units, having a first roller unit and a second roller unit the rollers of which are configured for moving sheet articles, and folding elements cooperating with the first roller unit and the second roller unit in order to arrange the sheet articles in an interfolded way, wherein: each roller unit of the set comprises a first part, a second part and, between them, a roller which is rotatable with respect to the first part and to the second part about a respective rotation axis;the first part and the second part of a roller unit of the set are distinct respectively from the first part and from the second part of another roller unit of the set;the frame comprises, for each roller unit of the set, a first seat which removably houses a respective first part and a second seat which removably houses a respective second part;the interfolding machine being characterised in that it is configured in such a way as to enable lifting the roller units of the set together.

12. The interfolding machine of claim 11, wherein the frame comprises a first upper part which bears idler rollers and/or drive rollers, a second upper part which bears idler rollers and/or drive rollers and a lower part which has the first seats and the second seats, wherein the first upper part and the second upper part are both hinged to the lower part and wherein the interfolding machine comprises at least an actuator which moves the first upper part and the second upper part between a first operating position and a second maintenance position in which the first upper part and the second upper part free the space above the roller units of the set so as to enable the lifting thereof.