Patent Description:
The invention also relates to a method of forming and fanfolding a sheet material, such as corrugated cardboard.

Sheet materials, typically corrugated cardboard, have been long known to be used in box package production in the form of a web of sheet material that is folded into a fanfold arrangement to reduce bulk and facilitate handling.

In fact, the raw sheet material is initially provided as a continuous web, like the continuous forms of old dot-matrix printers, i.e., consisting of a continuous sheet material of indefinite length composed of a succession of adjacent partitions or sections of equal size, known as partitions, delimited by fold lines and alternately folded one on top of the other to form a stack of superimposed partitions.

The stacks of equal or different sizes are loaded into the magazines of an automatic or semi-automatic machine or plant for manufacturing boxes of desired sizes.

In order to obtain a stack, the continuous web initially undergoes a process of forming fold lines transverse to the longitudinal direction of the continuous web, normally by means of a creaser with at least two opposed pressing rollers for forming creases on the two sides of the continuous web that divide adjacent partitions.

Once the fold lines or creases have been formed, the web undergoes a fanfolding step, i.e., alternate folding of adjacent partitions one on top of the other, followed by a step of stacking in a final unloading unit and cutting to a desired or standard height.

Then, the fanfold stacks of sheet material are loaded into one or more storage magazines of a cutting and creasing machine from which the partitions are successively deployed and carried to feed the cutting and creasing units which will form single pieces (blankets) to be assembled into boxes.

<CIT>, <CIT> and <CIT> disclose apparatuses for folding and stacking a continuous web into flat partitions. An apparatus of the type disclosed above is known form <CIT>, which has a feeding device for feeding a strip of sheet and a number of support elements which are guided along an annular guide for supporting the strip at the fold lines.

Furthermore, the support elements have an individual actuation control and can be displaced perpendicular to the direction of feed of the continuous web. The continuous web has a horizontal orientation relative to the feed device.

One drawback of this known system is that the fold lines are formed on one side only of the strip and the support elements always support the strip from the bottom. This may cause the formation of press creases in the strip also due to continuous changes of the feeding speed of the support elements.

Furthermore, the support elements project in cantilever fashion and laterally retract laterally to slide out of the fold lines and at this time the feeding speed decreases, thereby strongly affecting the working speed of the entire device.

<CIT> discloses a folding device equipped with a guided latch member for displacing a corrugated cardboard web at a fold. Further latch members are guided independently of the former latch member to carry along the corrugated cardboard web at another fold, which is arranged upstream of the former fold.

Also, a stacking device is arranged downstream of a folding device for stacking the corrugated cardboard web, which is folded along the folds to form stacks.

One drawback of this known folding device is that once again the latch members operate on the cardboard web on one side only at one every two fold lines and cannot avoid the formation of press creases in the vicinity of the first latch member. Furthermore, the feeding speed is limited by the complexity of the mechanism for moving the independent latch members elements, which are driven by annular belts or chains.

A further drawback is that each time the stack has to be cut, the feeding speed of the continuous web decreases to allow the partition to be cut higher than the stack.

In the light of the prior art, the technical problem addressed by the present invention consists in preventing the formation of press creases on the continuous web, while increasing the folding and stacking speed of the system.

The object of the present invention is to solve the above discussed problem, by providing a system and a method for forming and fanfolding a sheet material, such as corrugated cardboard, from a continuous web of indefinite length that are highly efficient and cost-effective.

A particular object of the present invention is to provide a system as discussed above that can minimize the formation of press creases near the fold lines while keeping the partitions of the continuous web flat and undeformed.

Another object of the present invention is to provide a system as discussed above that can guide the continuous web at high speed.

A further object of the present invention is to provide a system as discussed above that can be easily adapted to continuous webs of different widths without changing or replacing the folding tools.

These and other objects, as more clearly explained hereafter, are fulfilled by a system for forming and fanfolding a sheet material, such as corrugated cardboard, from a continuous web of indefinite length having a bottom side, a top side and longitudinal side edges, as defined in claim <NUM>.

The system comprises a frame defining a vertical center plane, a feeding device having means for guiding the continuous web in a longitudinal direction, a creasing device located downstream of the feeding device to form transverse creases on the continuous web, spaced apart at a constant longitudinal pitch and defining adjacent partitions, and a folding device located downstream of the creasing device to progressively and alternately fanfold adjacent partitions along the creases.

According to a peculiar aspect of the invention, the folding device comprises at least one first group of thrust tools acting on the creases formed on the bottom side of the continuous web and at least one second group of thrust tools acting on the creases formed on the top side of the continuous web, wherein the tools of each group are mechanically connected to and operably dependent on each other so that all the tools of the same group are forced to follow the same trajectory.

Since the thrust tools act on the fold lines from both sides of the continuous web, the latter is progressively guided and accompanied toward the fanfolding zone without leaving free unguided zones and is prevented from being folded in any undesired manner.

This arrangement allows alternate operation on successive fold lines alternately formed at the creases from opposite sides of the continuous web, to keep the adjacent partitions well laid and avoid the formation of press creases.

Conveniently, a first operating assembly for supporting the first group of tools and a second operating assembly, separate from but dependent on the first assembly, for supporting the second group of tools are mounted to the frame.

This allows coordinated handling of the thrust tools to act simultaneously on the opposite faces of the continuous web.

The invention also relates to a method of forming, fanfolding and stacking a sheet material, such as corrugated cardboard, according to the invention, as defined in claim <NUM>.

Advantageous embodiments of the invention are as defined in the dependent claims.

Further features and advantages of the invention will be more apparent from the detailed description of a system for forming and fanfolding a sheet material, such as corrugated cardboard, from a sheet material, such as corrugated cardboard, which is described as a non-limiting example with the help of the annexed drawings, in which:.

Particularly referring to the figures, there is shown a system, generally designated by numeral <NUM>, for forming and fanfolding a sheet material, such as corrugated cardboard, from a continuous web M of indefinite length having a bottom side S<NUM>, a top side S<NUM> and longitudinal side edges B.

As is known per se, the continuous web M is substantially longitudinal and comprises a predetermined maximum width E defined by the distance of the longitudinal side edges B.

As best shown in <FIG>, the system <NUM> comprises a frame defining a vertical center plane π and a feeding device, not shown, having means for guiding the continuous web M along a longitudinal direction L parallel to the vertical center plane π.

A creasing device <NUM> is also provided downstream of the feeding device and is adapted to form transverse creases C on the continuous web M, spaced apart at a constant longitudinal pitch K and defining adjacent partitions P.

The creasing device <NUM> comprises a frame <NUM>' having a pair of side walls <NUM> and adapted to support a first pair of no-crush wheels <NUM> for input of the web M from the feeding device, a pair of creasing rollers <NUM> and a second pair of no-crush wheels <NUM> for output of the web M after creasing.

As best shown in <FIG>, the pair of creasing rollers <NUM> are motorized and comprise a lower roller <NUM>' and an upper roller <NUM>" rotating about their respective axes X<NUM>, X<NUM> substantially parallel to each other and perpendicular to the longitudinal direction of feed L of the web M to be creased.

Advantageously, each creasing roller <NUM>', <NUM>" comprises a light-weight support frame <NUM> having a high bending resistance.

In a preferred embodiment of the creasing device <NUM>, the frame <NUM> comprises a plurality of disk-shaped elements <NUM> arranged at equally spaced axial positions and connected to each other by transverse rods or bars <NUM>, parallel to the axis X<NUM>, X<NUM> of each roller <NUM>', <NUM>" to stiffen the frame and counteract bending stresses, as best shown in <FIG>.

Preferably, the disc-shaped elements <NUM> are made of sheet metal and have a circular peripheral edge <NUM>' and a plurality of weight-reducing holes <NUM>.

Advantageously, the creasing rollers <NUM>', <NUM>" are each equipped with a male tool <NUM> and a female tool <NUM> fixed transverse to the circular edge <NUM>' of the disc-shaped elements <NUM> in diametrically opposite and perpendicular positions.

In other words, each creasing roller <NUM>', <NUM>" has a male tool <NUM> and a female tool <NUM> arranged at <NUM>° and along the circular arc of the disk-shaped elements <NUM> substantially corresponding to the value of the longitudinal pitch K between the creases of the creased continuous web M.

As best shown in <FIG>, the male tool <NUM> of a creasing roller <NUM>' is mounted in a position that is diametrically opposite and perpendicular to the female tool <NUM> of the other creasing roller <NUM>".

Thus, the creasing device <NUM> is configured to form creases C alternately on the bottom side S<NUM> and on the top side S<NUM> of the continuous web M for forming "Z" folds.

Therefore, at the output of the creasing device <NUM>, the web M will alternately and successively comprise a crease C<NUM> formed on the bottom side S<NUM>, for folding the web M upwards, and a crease C<NUM> formed on the top side S<NUM>, for folding the web M downwards.

It will be understood that the <NUM>° mutual arrangement of the creasing tools <NUM>, <NUM> allows the continuous web M to be processed at a constant angular speed.

Preferably, the tools <NUM>, <NUM> are conveniently removable from their respective rollers <NUM>', <NUM>" for maintenance and/or replacement and tools of convenient shape may be installed, depending on the type of creasing desired and the type of sheet material to be processed.

Furthermore, the particular "open" structure, consisting of multiple disk-shaped elements <NUM> with the transverse rods or bars <NUM> mounted thereto and the "squirrel cage" structure of the creasing rollers <NUM>', <NUM>", has a very light weight and a high flexural strength due to the disk-shaped stiffeners in a direction parallel to the direction of feed of the continuous web M which limit transverse deformation.

This flexural strength ensures a substantially constant pressure along the axial extent of the creasing rollers <NUM>', <NUM>", thereby providing more uniform and consistent depth of the creases C and improved folding of the form M.

Conveniently, the system <NUM> comprises a folding device <NUM> located downstream of the creasing device <NUM> for progressively and alternately fanfolding adjacent partitions P along the creases C.

In a particular aspect of the invention, the folding device <NUM> comprises at least one first group of thrust tools <NUM> acting on the creases C<NUM> formed on the bottom side S<NUM> of the continuous web M and at least one second group of thrust tools <NUM> acting on the creases C<NUM> formed on the top side S<NUM> of the continuous web M.

Advantageously, the thrust tools <NUM>, <NUM> of each group of tools <NUM>, <NUM> are mechanically connected to and operatively dependent on each other so that all the tools <NUM>, <NUM> of the same group will be forced to follow the same trajectory T<NUM>, T<NUM>.

<FIG> shows a side view of the folding device <NUM> in which the trajectories T<NUM>, T<NUM> of the first <NUM> and the second group <NUM> of thrust tools respectively are drawn as solid lines, and the continuous web M is temporarily folded to a "Z" shape by the two groups of thrust tools <NUM>, <NUM>, and having a development interposed between the two trajectories T<NUM>, T<NUM>.

Thus, the first group of tools <NUM> comprises first thrust tools <NUM> configured to temporarily push the creases C<NUM> formed on the bottom side S<NUM> of the continuous web M upwards, and the second group of tools <NUM> comprises second thrust tools <NUM> configured to temporarily push the creases C<NUM> formed on the top side S<NUM> of the continuous web M downwards.

As best shown in the figures, each thrust tool <NUM>, <NUM> is a substantially horizontal elongate member, which is transverse and perpendicular to the center plane π.

It will be noted that the thrust tools <NUM>, <NUM> alternately act on the creases C<NUM>, C<NUM> and on the sides S<NUM>, S<NUM> of the continuous web M, so that that the latter will be progressively guided and accompanied toward the fanfolding zone without leaving free unguided zones, and preventing it from being folded in any undesired manner.

In other words, the particular arrangement of the thrust tools <NUM>, <NUM> and their respective groups of tools <NUM>, <NUM> affords action on successive fold lines, alternately formed on the creases C<NUM>, C<NUM> of the opposite sides S<NUM>, S<NUM> of the continuous web M to keep adjacent partitions P well stretched and to avoid the formation of press creases.

As more clearly shown in <FIG>, the folding device <NUM> comprises a frame <NUM>" having mounted thereto a first operating assembly <NUM> for supporting a moving the first group <NUM> of thrust tools <NUM> and a second operating assembly <NUM>, distinct from and independent of the first assembly <NUM>, for supporting the second group <NUM> of thrust tools <NUM>.

The first <NUM> and the second <NUM> operating assemblies respectively comprise, a first <NUM> and a second pairs <NUM> of supporting wheels, facing other about the vertical center plane π, and the supporting wheels of each pair <NUM>, <NUM> are substantially vertical and symmetric about the center plane π.

As best shown in <FIG>, the supporting wheels of the first pair <NUM> are rigidly fixed to a first transverse shaft <NUM> driven by a first motor <NUM> and are located at a first transverse distance d<NUM> that is greater than the maximum width E of the continuous web M.

In addition, the supporting wheels of the second pair <NUM> are rigidly fixed to a second transverse shaft <NUM> driven by a second motor <NUM> and are located at a second transverse distance d<NUM> that is greater than the maximum width E of the continuous web M and greater than the first transverse distance d<NUM>.

Therefore, the first <NUM> and the second pairs <NUM> of supporting wheels are able to rotate along respective horizontal axes X<NUM>, X<NUM> perpendicular to the center plane π and the first <NUM>, and second transverse shafts <NUM> are concentric with the axis X<NUM>. X<NUM> of each pair <NUM>, <NUM> of supporting wheels.

Moreover, the first <NUM> and the second transverse shafts <NUM> are rotatably mounted to the frame <NUM>" in longitudinally offset positions and with the second shaft <NUM> downstream of to the first shaft <NUM>.

In the embodiment as shown in the figures, the supporting wheels of each pair <NUM>, <NUM> substantially have a cross shape, with the transverse shafts <NUM>, <NUM> extending from the center thereof.

However, this does not exclude that the supporting wheels of each pair <NUM>, <NUM> may have a shape other from those as described heretofore.

Advantageously, the thrust tools <NUM>, <NUM> of the same group <NUM>, <NUM> are supported at the free ends of first series <NUM> and second series of articulated arms <NUM>, as further described below.

As best shown in <FIG>, respective first series of articulated arms <NUM> are mounted near the peripheral edge <NUM>' of the first pair of wheels <NUM>, and are each driven by a respective first drive <NUM> whose transverse axis X<NUM> is perpendicular to the center plane π.

Likewise, respective second series of articulated arms <NUM> are mounted near the peripheral edge <NUM>' of the second pair of wheels <NUM>, and are each driven by a respective second drive <NUM> whose transverse axis X<NUM> is perpendicular to the center plane π.

The articulated arms of the first series <NUM> and the articulated arms of the second series <NUM> are in side-by-side relationship, and are directed radially outwards with respect to the respective pair of supporting wheels <NUM>, <NUM> and constantly facing each other about the center plane π.

Advantageously, the articulated arms of the first series <NUM> are configured to support the first group of thrust tools <NUM> at their free ends and are formed by respective first pairs of elongate members <NUM> connected to each other by third drives <NUM> with transverse axes of oscillation X<NUM> perpendicular to the center plane π.

The articulated arms of the second series <NUM> are configured to support the second group of thrust tools <NUM> at their free ends and are formed by respective second pairs of elongate members <NUM> connected to each other by fourth drives <NUM> with transverse axes of oscillation X<NUM> perpendicular to center plane π.

Conveniently, the third <NUM> and fourth drives <NUM> are configured to impart a relative oscillation to the respective elongate members <NUM>, <NUM> about the respective transverse axes of oscillation X<NUM>, X<NUM>.

It will be understood that each of the drives <NUM>, <NUM>, <NUM>, <NUM> is operably coupled to the first <NUM> and the second motors <NUM> and is configured to keep the articulated arms of each series <NUM>, <NUM> constantly paired and the thrust tools <NUM>, <NUM> substantially parallel to each other and perpendicular to the longitudinal direction L.

In a first embodiment of the system <NUM>, as shown in <FIG>, the first drive <NUM> and the second drive <NUM> comprise a third motor <NUM> and a fourth motor <NUM>, respectively, and the third drives <NUM> and the fourth drives <NUM> comprise fifth motors <NUM> and sixth motors <NUM>, respectively, in which the motors <NUM>-<NUM> are operably coupled to the first motor <NUM> and to the second motor <NUM>.

In a second embodiment of the system <NUM>, not shown in the figures, the first drive <NUM> and the second drive <NUM>, the third drives <NUM> and the fourth drives <NUM> are of mechanical cam type and operably coupled to the first motor <NUM> and the second motor <NUM>.

Cam-type mechanical actuators refer to mechanical members of chain, belt and gear types, for constraining motion to the first motor <NUM> and the second motor <NUM>.

Of course, the first motor <NUM>, the second motor <NUM> and the third, fourth, fifth and sixth motors <NUM>-<NUM> are controlled by a control unit, not shown, which is able to set the first and second differentiated and non-interfering trajectories T<NUM>, T<NUM> to the first <NUM> and the second groups <NUM> of tools respectively.

Accordingly, the control unit is adapted to set the first and second paths W<NUM>, W<NUM> respectively to the creases C<NUM>, C<NUM> of the sides S<NUM>, S<NUM>.

As best shown in <FIG> and <FIG>, the first operating assembly <NUM> with the first pair of supporting wheels <NUM> is mounted to the frame <NUM>" directly downstream of the creasing device <NUM>, whereas the second operating assembly <NUM> with the second pair of supporting wheels <NUM> is mounted to the frame <NUM>" downstream of and partially upwards with respect to the first operating assembly <NUM>.

The relative position of the first <NUM> and the second operating assemblies <NUM> is determined in view of facilitating the alternating interaction on the creases C<NUM>, C<NUM> with no mutual interference of the respective pairs of elongate members <NUM>, <NUM> and the respective thrust tools <NUM>, <NUM>.

Thus, the creases C<NUM> of the bottom side S<NUM> are pushed by the thrust tools <NUM> first upwards and then toward the second group of tools <NUM>, whereas the creases C<NUM> of the top side S<NUM> are pushed by the thrust tools <NUM> first downwards and then toward the first group of tools <NUM>, as illustrated by the paths W<NUM>, W<NUM> of the creases C<NUM>, C<NUM> in <FIG>.

This allows coordinated handling of the thrust tools <NUM>, <NUM> to act simultaneously on the opposite sides S<NUM>, S<NUM> of the continuous web M.

In <FIG>, one of the first pairs of elongate members <NUM> and one of the second pairs of elongate members <NUM> are shown respectively as dashed surfaces during operation of the folding device <NUM>.

It will be appreciated herein that the continuous web M is constantly supported by at least four thrust tools <NUM>, <NUM> and always at the respective creases C<NUM>, C<NUM> to maintain the adjacent partitions P of the continuous web M flat and undeformed.

Thus, the thrust tools <NUM>, <NUM> act on their respective creases C<NUM>, C<NUM> on both sides S<NUM>, S<NUM> of the continuous web M and the latter is progressively guided and accompanied toward the fanfolding zone without leaving free unguided zones and preventing any undesired folding thereof.

In particular, <FIG> show how the thrust tools <NUM>, <NUM> move away from their respective crease C<NUM>, C<NUM> without interfering with the respective adjacent partitions P and only when the latter form a predetermined folding angle to prevent the weight of the continuous web M from generating press creases near the fold lines.

In a further aspect, there is provided a method of forming and fanfolding a sheet material, such as corrugated cardboard, from a continuous web M of indefinite length having a bottom side S<NUM>, a top side S<NUM> and longitudinal side edges B.

Il will be appreciated from the foregoing that the system for forming and fanfolding a sheet material and the method according to the invention fulfill the intended objects and namely prevent the formation of press folds in the continuous web, while increasing the folding speed of the system.

The system and method of operation of the invention are susceptible to a number of changes and variants within the inventive concept as disclosed in the annexed claims.

While the system and method of operation have been described with particular reference to the accompanying figures, the numerals referred to in the disclosure and claims are only used for the sake of a better intelligibility of the invention and shall not be intended to limit the claimed scope in any manner.

Reference herein to "one embodiment" or "the embodiment" or "some embodiments" indicates that a particular characteristic, structure or element that is being described is included in at least one embodiment of the inventive subject matter.

Claim 1:
A system (<NUM>) for forming and fanfolding a sheet material, such as corrugated cardboard, from a continuous web (M) of indefinite length having a bottom side (S<NUM>), a top side (S<NUM>) and longitudinal side edges (B), which system (<NUM>) comprises:
- a frame (<NUM>', <NUM>") defining a vertical center plane (π);
- a feeding device having means for guiding the continuous web (M) in a longitudinal direction (L);
- a creasing device (<NUM>) located downstream of said feeding device to form transverse creases (C<NUM>, C<NUM>) on the continuous web (M) spaced apart at a constant longitudinal pitch (K) and defining adjacent partitions (P);
- a folding device (<NUM>) located downstream of said creasing device (<NUM>) for progressively and alternately fanfolding the adjacent partitions (P) along the creases (C<NUM>, C<NUM>);
wherein said folding device (<NUM>) comprises at least one first group (<NUM>) of thrust tools (<NUM>) acting on the creases (C<NUM>) formed on the bottom side (S<NUM>) of the continuous web (M) and at least one second group (<NUM>) of thrust tools (<NUM>) acting on the creases (C<NUM>) formed on the top side (S<NUM>) of the continuous web (M);
wherein said thrust tools (<NUM>, <NUM>) of each group (<NUM>, <NUM>) are mechanically connected to and operably dependent on each other so that all the tools (<NUM>, <NUM>) of the same group (<NUM>, <NUM>) will be forced to follow the same trajectory (T<NUM>, T<NUM>);
characterized in that the thrust tools (<NUM>, <NUM>) of the same group (<NUM>, <NUM>) are supported at the free ends of first series (<NUM>) and second series of articulated arms (<NUM>).