Patent Description:
Sheet element decks can be made from paper, cardboard (including corrugated board) or plastic which is printed or laminated. Usually, such sheet elements are printed or laminated by using a blank from which the sheet elements are die-cut in a converting machine. The sheet elements are transported one after the other in rows to be subsequently stacked in decks.

For a method and a device for stacking it is decisive that the sheet elements are arranged in a given sequence within the deck and that a jam of sheet elements during transport and stacking is avoided. A typical example where stacking in a fixed sequence is required is a deck of playing cards. In most cases, each card is different from the other within one deck. The playing cards needs to be arranged in a predetermined succession, e.g. the playing cards of one color shall be arranged one after the other.

Documents <CIT> and<CIT> disclose examples of stacking devices for stacking and accumulating sheet elements behind a stop member. When a desired number of sheet elements have been stacked, the stop member moves away and releases the formed stack.

Document <CIT> discloses a printer-lane packaging method for printing document sets having a variable number of sheet pages. The sheets can first be isolated so that required document sets are generated, then stacked and packaged.

Document <CIT> discloses an apparatus for producing a deck of cards. The apparatus comprises conveyor belts arranged to feed sheet elements into a first sorting device overlapping cutout sheet elements on top of each other. An additional cutting device is arranged further downstream and is configured to cut the sheet elements into separate cards, while feeding the cards into a funnel-shaped stacking device so that they form a deck.

Document <CIT> discloses a device for creating collations in the form of document stacks. Such collations can for instance be inserted into envelopes. The device comprises a plurality of drive belts provided with projections. A first pair of projections can abut against a leading front edge of a stack while a second pair of projections can abut against a rear end of the stack.

It is an object of the present invention to provide a method and a stacking device for generating decks of sheet elements wherein the sheet elements are perfectly aligned to each other and wherein a jam of sheet elements during transportation and stacking is avoided.

This object is achieved by a method for generating decks of sheet elements, comprising the steps of:.

wherein the stop member is moved in the transport direction with a lower velocity than a velocity of the transport surface.

The term "completely shifted underneath" means that the lowermost sheet is completely contained underneath the uppermost sheet element. In such a position, the uppermost and lowermost sheet elements are aligned by their surrounding edges.

It has been found that the sheet elements lying on a transport surface, i.e. moving surface, may slide underneath each other only perfectly, if the last sheet element in the row of overlapping sheet elements is the lowermost in order to have a large contact area to the transport surface. The deck is generated starting from its uppermost sheet element, and lower sheet elements reaching the stop member are shifted underneath during formation of the deck. The present invention does neither need plates moving towards each other in order to shift the sheet elements onto each other nor suction devices for engaging the individual sheet elements in order to stack them.

A moving stop member allows to maintain a flow of sheet elements and a flow of the decks. The leading stop member thus overrides the movement of the row of sheet elements on the transport surface in the transport direction.

Preferably, the sheet elements are positioned so that adjacent sheet elements are overlapping before being moved relative to each other. The sheet elements can be rectangular with rounded corners, as shown in the figures, but can also have different shapes, for example unfolded boxes, squares or rectangles without rounded corners, as long as front end of the sheet element can be effectively stopped and maintained in a well-defined orientation by the stop member.

In an embodiment, at least one endless belt is used for the transport device. The upper portion of the belt, more precisely its upper surface, defines the transport device.

The sheet elements may be positioned one behind each other on a transport device of an inlet station without overlapping each other. In the inlet station or at the end thereof, the sheet elements are repositioned to partly overlap by decelerating the sheet elements one after the other. Thus, subsequently arriving sheet elements are partly slipping underneath their front sheet element.

In an embodiment, rows of a set of overlapping sheet elements are arranged parallel to each other and the sheet elements of each row are stacked. The rows are arranged so that their longitudinal extension coincide with the direction of transportation.

Thus, each row comprises the sheet elements of a partial deck, and the partial decks from each row are together defining the final, large deck. In order to generate a complete deck, the partial decks defined by parallel rows are shifted transverse or perpendicular to the transport direction after being stacked to form the common, larger deck.

The present invention also provides a stacking device. The stacking device is configured to generateesheet element decks and comprises.

The term "endless belt" comprises a belt as well as an endless chain or any known device which implements the same function.

The stop member may protrude upwardly from underneath a plane defined by the transport surface. This allows the device to be designed compactly.

The stop member can be attached to an endless belt which is arranged underneath the plane. This endless belt may also have several stop members distanced from each other so that during one revolution of the endless belt several decks of sheet elements are generated.

Preferably, the transport devices are defined by endless belts, wherein between adjacent endless belts a stop member is arranged.

The stop member is fixed to a separate endless belt.

To each endless belt of the transport device two stop members are assigned, one stop member on each longitudinal edge of the associated endless belt. Each sheet element being preferably transported by one endless belt of the transport device and stopped by two stop members, but the reverse is also possible: each sheet can be transported by two endless belts of the transport device and stopped by one single stop member, in which case two endless belts are assigned to each stop member. The first alternative being preferred because the stability of the sheet element is better, and thus the adjustment of the first stacking station less critical.

The endless belts of the transport device and of the stop members are arranged offset in transport direction, in particular wherein the endless belts of the stop members are taking over the decks from the endless belts of the transport device after the end of the transport device in transport direction.

Furthermore, several transport sub-devices for sheet elements can be arranged parallel to each other, in particular wherein a stop member is aligned between adjacent transport sub-devices of sheet elements. One stop member may be assigned to two adjacent rows of sheet elements.

In an embodiment, one common drive for the transport sub-devices for the sheet elements and/or one common drive for the stop members are or is provided. This reduces the number of parts enables the stacking device to be conceived in a cost-efficient manner. One example to carry out this feature is to have one common driving roller onto which several endless belts are wound.

The stacking device comprises at least one slider movable crosswise to the transport direction to shift adjacent decks towards each other and above each other to form a common deck. The slider can be part of a station or module which is arranged immediately after rows of sheet elements are pushed together to form partial decks lying side by side.

In an embodiment, an inlet station is arranged before the stacking station and a decelerating element is provided for contacting the upper surfaces of the sheet elements in order to arrange a row of overlapping sheet elements. The row of overlapping sheet elements is transported to the stacking station.

In <FIG>, a stacking device for generating decks of sheet elements made of printed and/or laminated paper, cardboard or plastic is shown. The device comprises four stations or modules, an inlet station <NUM>, a first stacking station <NUM>, a second stacking station <NUM> and a subsequent outlet station <NUM>. The stacking device can, however, comprise the first stacking station <NUM> without the second stacking station <NUM>.

In the shown example, sheet elements <NUM> are printed playing cards positioned next to each other without contacting each other in rows R and columns C. A set of sheet elements <NUM> is defined by all sheet elements <NUM> of one row R.

All stations <NUM> to <NUM> comprise transport means which are moving the sheet elements <NUM> in a common transport direction T. The transport direction T coincides with the direction of rows R, which is also referred to as the longitudinal direction.

Inlet station <NUM> comprises an endless belt drive with a belt <NUM>. Driving and deflecting rollers are not shown in this figure in order to increase the clarity.

Sheet elements <NUM> are placed onto the upper portion of the belt <NUM>. The upper portion of the belt <NUM> forming a transport table. More specifically, the sheet elements <NUM> are received from a printing press and a subsequent die-cutting machine.

At the end of inlet station <NUM> and belt <NUM> a deceleration element <NUM> is provided. Deceleration element <NUM> can be a roller or cylinder having an elastomeric surface.

The transport device <NUM> of the first stacking station <NUM> is designed as a transport table with a transport surface shown in <FIG> defined by several parallel commonly driven endless belts <NUM> which define transport sub-devices.

Underneath decelerating element <NUM>, a deepened or lower portion <NUM> is provided, as shown in <FIG>.

As in the illustrated embodiment, the lower portion is achieved by arranging the upper surface of the belt <NUM> at a vertically lower height than the upper surface of the belt <NUM>.

The tangential speed of the decelerating element <NUM> and the speed of the belt <NUM> is equal. The decelerating element <NUM> and the belt <NUM> are travelling slower than the belt <NUM>. The lower portion <NUM> causes the back edge of a preceding sheet element <NUM> to be raised when received in-between the decelerating element <NUM> and the belt <NUM>. The preceding sheet element <NUM> travels slower than the following sheet <NUM>, which is on belt <NUM> and whose front side gets shifted underneath the raised back side of sheet element <NUM>. This allows the generation of an inverted shingle stream of elements. The back and front of the sheet elements are defined with respect to the transport direction.

The decelerating element <NUM> and the lower portion <NUM> are cooperating to arrange sheet elements <NUM> of each row R in an overlapping manner, partly on top of each other as shown in <FIG>. These overlapping adjacent sheet elements overlap by a given overlap distance O at the entry of the first stacking station and before being stacked further by the first stacking station. The overlap distance O can vary depending on the shape and material of the sheet elements. For example, the overlap distance O may correspond to a percentage of between to <NUM> to <NUM>% of the length of the sheet elements <NUM> in the direction of transport T, i.e. for rectangular shaped sheet elements <NUM>. Such an overlap distance O ensures that the sheet elements <NUM> perform a gradual and continuous overlap in the stacking station <NUM>. This avoids an abrupt deceleration of the sheet elements <NUM> and thus prevents a loss in production speed. The percentage may be set in an adjustment phase by conducting some trial-and-error tests.

Hence, in order to overlap the sheet elements <NUM> and <NUM> in an inversed manner there is a need for a height difference between the belt <NUM> of the inlet station <NUM> and the downstream-located belt <NUM>, in combination with decelerating a preceding sheet element <NUM> in relation to a following sheet element <NUM>. This creates the i an inverted shingle stream of elements <NUM>.

Therefore, in a non-illustrated alternative embodiment, the upper surface of belt <NUM> can be located at a vertically lower height than the upper surface of the belt <NUM>. The belt <NUM> is then arranged at such a height distance and horizontal distance from the belt <NUM> so that the leading front edge of the sheet elements <NUM> grasped and guided upwardly to be driven by the belt <NUM> in the transport direction T.

The specific arrangement of sheet elements <NUM> at the rear end portion of stacking station <NUM> is shown in <FIG>. The first (front) sheet element <NUM> of each row R defines the uppermost sheet element of the row R and the last (rear) sheet element <NUM> defines the lowermost sheet element of the row R. In more detail, the last sheet element <NUM> lies with its complete underside on the transport device <NUM>. The immediately adjacent (here the middle) sheet element <NUM> has a rear end <NUM> lying on the upper side of the front end <NUM> of sheet element <NUM>. The sheet element adjacent to sheet element <NUM> in transport direction T, here the first sheet element <NUM> lies with its rear end <NUM> on the upper side of the front end <NUM> of sheet element <NUM>. Thus, first sheet element <NUM> is the uppermost and last sheet element <NUM> is the lowermost sheet element. We call this arrangement of sheet elements an inverted shingle stream of elements. The rear and the front are defined with respect to transport direction, the sheets elements being transported from rear to front.

The transport device <NUM> of the first stacking station <NUM> is designed as a transport table with a transport surface shown in <FIG> defined by several parallel commonly driven endless belts <NUM> which define transport sub-devices. Belts <NUM> have common driving and deflecting rollers. A first driving or deflecting roller (not shown) is arranged underneath and close to deceleration element <NUM>.

Between adjacent endless belts <NUM> and, preferably, along the outer edges of the outermost endless belts <NUM> (seen in transport direction T) drive elements <NUM> in the form of endless belts are arranged parallel to endless belts <NUM>. The transport surface defined by the upper sides of the upper portions of endless belts <NUM> is arranged above a plane defined by the upper sides of the upper portions of drive elements <NUM> so that sheet elements <NUM> are not contacting the upper sides of drive elements <NUM> but the upper sides of belts <NUM>, only.

As can be seen from <FIG> and <FIG>, the loops defined by endless belts <NUM> and drive elements <NUM> are offset in transport direction T, in other words, when moving along transport direction, the loop defined by drive elements <NUM> start before and ends before the loop defined by endless belt <NUM>.

The plurality of drive elements <NUM> may also have common driving and deflecting rollers so as to move with the same velocity.

On each endless drive element <NUM>, one or more stop members <NUM> are attached and are protruding upwardly (when the respective portion of endless belt of drive element <NUM> defines the upper portion) as seen in <FIG>. Each stop member <NUM> is plate-like and extends transversely to transport direction T, preferably along the full width of drive element <NUM>. Stop members <NUM> extend and protrude over the transport surface defined by the upper surfaces of endless belts <NUM>. The height of the stop members <NUM> may correspond to or exceed the height of each partial deck in each row R.

The first stacking station <NUM> is configured to form decks of sheet elements of each single row R.

When sheet elements <NUM> are aligned at the front end of transport device <NUM> to overlap, the sheet elements are moved forward by endless belts <NUM>. Drive elements <NUM> are driven with a velocity which is lower than the velocity of endless belts <NUM>. Thus, the first sheet elements <NUM> reach and contact the slower stop members <NUM> when being transported by endless belts <NUM> in transport direction T. <FIG> shows the first contact of the front ends of the first sheet elements <NUM> with the stop members <NUM>.

As can be seen from <FIG>, the middle stop members <NUM> are contacted by the first sheet elements <NUM> of adjacent rows. Thus, each sheet element <NUM> is decelerated by two stop members <NUM> at their left and right hand edges seen in transport direction T.

Due to the deceleration of the first sheet element <NUM>, the middle sheet element <NUM> and the last sheet element <NUM> are still moved forward by endless belts <NUM> and are sliding underneath the first sheet element <NUM> of their associated row. Thus, at the end of the transport track of endless belts <NUM>, a deck <NUM> of each row R of sheet elements <NUM> is formed.

As the loops of endless belts <NUM> are ending in transport direction T before the loops of drive elements <NUM> (see <FIG>) the decks <NUM> are taken over by drive elements <NUM>. The speed of the first sheet elements <NUM> in the first column C in the first stacking station <NUM> is thus defined by the drive elements <NUM>, as the first sheet elements <NUM> abut against the stop members <NUM>. Hence, the speed of all the sheet elements <NUM> is decreased from the speed of the belt <NUM> to the speed of the drive elements <NUM> at the outlet end of the first stacking station <NUM>. Plate-like vertical sliders <NUM> are bridging a gap between the ends of the loops of drive elements <NUM> and a subsequent endless belt or several adjacent endless belts <NUM> of the second stacking station <NUM>. Thus, drive elements <NUM> are delivering decks <NUM> to endless belt <NUM>. Optionally, a slope can be arranged on sliders <NUM> so as to help the sheet elements to slide (downwards) toward endless belts <NUM>. Optionally, as an alternative, an additional set of endless belts with a protruding member can be arranged above the sheet elements and above the plate-like vertical slides <NUM> to push the sheet elements (with the protruding member) in the transition zone between the first stacking station <NUM> and the second stacking station <NUM>.

The second stacking station <NUM> is stacking the partial sheet elements stacks transverse to the transport direction T. Endless belt <NUM> has several tracks <NUM> to <NUM>, each track <NUM> to <NUM> is assigned to a row R. The stacks are transported from an upstream track <NUM> to a downstream track <NUM>. Each track has an upstream track side <NUM>, which is the longitudinal side that is closer to the upstream track. Each track has also a downstream track side <NUM> which is the longitudinal side that is closer to the downstream row. "Upstream" and "downstream" are defined according to the transversal direction, i.e. the direction perpendicular to the transport in the plane of the sheet elements; on the stacking second station <NUM>, the stacks are formed from upstream to downstream.

In order to ensure a proper stacking of the sheet elements stacks, a stack on an upstream track must slide above the stacks on the neighboring downstream track. Thus, the downstream track side <NUM> of an upstream track must lie above the upstream track side <NUM> of the neighboring downstream track, resulting in a staircase profile. The height difference between two stairs in the profile must be at least as large as the thickness of the stacks of sheet elements entering the second stacking station.

Slider <NUM> shifts decks <NUM> onto each other to form a common, larger deck. This is achieved by deck <NUM> on the upstream track <NUM> being moved onto adjacent deck <NUM> which is positioned underneath it on downstream tracks <NUM> to <NUM>.

Slider <NUM> shifts decks <NUM> to define one common deck <NUM> (see <FIG>) and, finally, shifts common deck <NUM> onto an endless belt <NUM> of outlet station <NUM>.

The present stacking device enables the creation of ordered decks <NUM> comprising a variable quantity of sheet elements <NUM>. Such a stacking device is suitable in the production of playing cards, as such decks may have a different number of cards <NUM>.

In a converting machine for use together with the present stacking device, the individual sheet elements or cards <NUM> are produced by printing and processing a substrate in sheet or web form. The printing can for instance be effectuated with a flexographic printing assembly. A die-cutter tool can be used downstream of the printing assembly and is used to cut out the individual sheets or cards <NUM>.

The die cutter tool is provided with a pre-defined cutting arrangement adapted to create cutouts to form the sheet element <NUM> in rows R and columns C. The arrangement of the rows R and columns C can be modified depending on the number of cards included in the complete deck <NUM>.

The stacking station <NUM> may therefore be configured to include a variable number of belts <NUM>, <NUM> in operation. The stacking station <NUM> can be provided with a number of belts <NUM>, <NUM> dimensioned for a maximum amount of rows R to be used. The stacking station <NUM> can be arranged to be slidable in a direction transverse or perpendicular to the direction of transportation. In such a way, the belts <NUM>, <NUM> can be aligned with the rows R of sheet elements <NUM>. This allows the position of the belts <NUM>, <NUM> to be laterally shifted to render one or several exteriorly located belts <NUM>, <NUM> inoperable (e.g. moving, but not receiving any sheets <NUM> or idle). This enables the stacking station <NUM> to adapt to job specifications with different number of rows R.

Claim 1:
Method for generating decks (<NUM>) of sheet elements (<NUM>), comprising the steps of
positioning a set of numerous sheet elements (<NUM>) onto a transport surface of a transport device (<NUM>) one after another such that the sheet elements (<NUM>) are partly overlapping with their adjacent sheet elements (<NUM>),
wherein the transport device (<NUM>) has a transport direction (T), and wherein the last sheet element (<NUM>) of the set with respect to the transport direction (T) is positioned to be the lowermost sheet element (<NUM>) of the set, and the other sheet elements (<NUM>) being positioned so that their rear end (<NUM>) lies onto the front ends (<NUM>) of the sheet element (<NUM>) being adjacent in counter-transport direction, so as to form a row (R) of overlapping sheet elements (<NUM>),
moving the row (R) of overlapping sheet elements (<NUM>) in the transport direction (T), and
moving the overlapping sheet elements (<NUM>) against a stop member (<NUM>), which is firstly contacted by the uppermost sheet element (<NUM>), until the lowermost sheet element (<NUM>) is completely shifted underneath an adjacent sheet element (<NUM>), and wherein the stop member (<NUM>) is moved in the transport direction (T) with a lower velocity than a velocity of the transport surface.