Patent Description:
The present invention relates to a roller conveying device, a connection machine, and a plant for the production of articles.

The present invention also relates to a method to extend a conveying device.

The present invention finds advantageous application in the conveyance of tiles between a manufacturing machine, for example a ceramic press, and a conveyor line, to which the following specification will make explicit reference without thereby losing generality.

Normally, a roller conveying device that picks up products from a manufacturing machine and deposits them on a conveyor line, or on another machine, is equipped with a set of manually removable rollers arranged in a portion of the conveying device that picks up the products coming out of said manufacturing machine. The removable rollers allow the portion of the conveying device that picks up the products coming out of the manufacturing machine to be moved closer and/or further away.

In the ceramic industry, this occurs when a roller conveying device is interposed between a ceramic press, which is configured to compact a powder ceramic material to form raw tiles (that are still unfired), and a subsequent conveyor line. The ceramic press is usually provided with moulds, the replacement of which allows the format or quantity (in the case of multiple formats) of the tiles produced to be changed. As the format changes, the size of the mould also changes (both in the case of single formats and in the case of multiple formats).

The position of a first roller, arranged in the portion of the conveying device that picks up the products coming out of the press, must therefore be adapted to the variation of the format, so as to ensure that, once manufactured, the tiles coming out of the press have an adequate support close to the mould. In fact, if the first roller is too far from the mould of the press, there is a risk of damaging the tiles (still unfired and therefore fragile).

Usually, when the format changes, rollers are manually added or removed in the vicinity of the ceramic press mould. However, these operations are not easy and quick to carry out, since the adjustment of the manually assembled rollers is extremely time-consuming and usually complex from the mechanical point of view due to the many hindrances generated by the ceramic press and the protections (partitions, screens, etc.) necessary near large machines to safeguard the operators. Consequently, it is common practice to move the roller conveying device so as to adapt it to the format of the press mould and then arrange the first roller in an optimal position with respect to the mould and the press.

Moreover, normally, the roller conveying device is provided, in the vicinity of the ceramic press, with a movable system, which allows the roller conveying device to be moved in order to free up space and allow ordinary and extraordinary maintenance operations, replacement of parts, format changes, etc. However, particularly in the case of large machines (such as ceramic presses), the space required to easily carry out maintenance or mould replacement operations is very large. This means that the space made available by the movable system of the roller conveying device is often insufficient to allow the assigned personnel to operate easily, or, in order to make a sufficient space available, the movable system of the roller conveying device must have a size such as to require very large spaces for its movement.

Some solutions, such as the one described in <CIT>, however, propose complex and expensive systems in order to allow space occupied by the roller conveying device to be freed, such as to allow both ordinary and extraordinary maintenance operations and format changes to be carried out easily.

Document <CIT> describes an extensible conveying device, which includes a portion with a fixed length and one with a variable length, which allows rollers to be added to or removed from a conveying path. As described in <CIT>, the extensible conveying device comprises a number of individually motorized rollers, by means of solutions displaying an internal motor in each motorized roller. However, the device proposed by <CIT> has several drawbacks, among which we mention: high construction and operating costs; relatively frequent maintenance interventions; the inability to convey items under a certain size; a relatively large number of items damaged during conveyance.

Document <CIT> discloses a transfer device for coupling a process device to a stationary station for the purpose of inward and/or outward transfer of piece goods. In such a device, at least one conveyor device has at least one magnetic coupling is formed for reversible coupling a transfer device to a corresponding drive element.

Document <CIT> discloses a roller conveying device according to the preamble of claim <NUM>.

The object of the present invention is to provide a roller conveying device, a connection machine, a plant and an extension method, which are at least partially free from the drawbacks described above and, at the same time, simple and inexpensive to manufacture.

The invention provides in a first aspect a roller conveying device according to claim <NUM>, in a second aspect a connection machine according to claim <NUM>, in a third aspect a plant for the production of articles according to claim <NUM> and in a fourth aspect a method to extend a roller conveying device according to claim <NUM>. Preferred embodiments of the invention become apparent from the dependent claims.

The present invention will now be described with reference to the appended drawings, which illustrate some non-limiting embodiments thereof, wherein:.

In <FIG>, the numeral <NUM> indicates, as a whole, an extensible roller conveying device in accordance with the first aspect of the present invention. The conveying device <NUM> is configured to convey articles AR along a path with a variable length L.

According to some non-limiting embodiments, the articles AR are ceramic industry articles, in particular tiles, more particularly unfired tiles.

The roller conveying device <NUM> comprises a roller conveyor <NUM>, which is provided with a plurality of rollers <NUM>. The roller conveyor <NUM> is configured to convey articles (for example unfired tiles) along (at least) one segment of the conveying path P. The roller conveying device <NUM> comprises an extension device <NUM> provided with rollers <NUM> and an actuator system <NUM>, which is configured to move, in particular in a combined manner, the rollers <NUM>. In this way, the length of the conveying device <NUM> can be varied by changing, downstream or upstream of the roller conveyor <NUM>, the number of rollers <NUM> along the conveying path P.

According to some non-limiting embodiments (such as those illustrated in the attached figures), the roller conveying device <NUM> is a conveying device for conveying ceramic industry articles, in particular tiles, more particularly unfired tiles.

The actuator system <NUM> is configured to move (at least) part of the rollers <NUM>. Advantageously, the actuator system <NUM> is configured to move (all) the rollers <NUM> (simultaneously).

The words "in a combined manner" are intended to mean that, when one of the rollers <NUM> moves, the other rollers <NUM> also move accordingly. In other words, if one of the rollers <NUM> is moved by the first actuator system <NUM>, the other rollers <NUM> will also be moved.

In some non-limiting cases, the motion of the rollers is mechanically constrained, consequently the rollers <NUM> are moved simultaneously by the actuator system <NUM>.

The roller conveying device <NUM> (particularly the extension device <NUM>) comprises an actuator system <NUM> to also move the roller conveyor <NUM> in a direction D substantially parallel to the conveying path P. This allows the roller conveyor <NUM> to be moved closer to (or further away from) a manufacturing machine which can be located upstream of the roller conveying device. In some non-limiting cases, as shown in <FIG>, the actuator system <NUM> allows the roller conveyor <NUM> to be moved closer to or further away from a ceramic press. Accordingly, the actuator system <NUM> allows the distance of the roller conveyor <NUM> from the ceramic press to be adapted, so as to adapt it to the change of format produced by the ceramic press.

According to the invention, the actuator system <NUM> is an independent actuator system (separate from the actuator system <NUM>) configured to move the roller conveyor <NUM> in a direction D substantially parallel to the conveying path P. In particular, in such cases, the actuator system <NUM> and the actuator system <NUM> are operated in a coordinated manner so that a movement of the roller conveyor <NUM> corresponds to a transfer of an equivalent number of rollers <NUM> along the path P.

According to some non-limiting embodiments, not shown, the (independent) actuator system <NUM> comprises an electric motor configured to move the roller conveyor <NUM> along guides <NUM> (of the device <NUM>). In particular, the guides <NUM> are two guides arranged parallel to the conveying path P. More particularly, the electric motor of the (independent) actuator system <NUM> is a rotary motor which allows the roller conveyor to be moved along the guides <NUM> by means of a ball screw.

According to a further embodiment, not shown, the (independent) actuator system <NUM> comprises (at least) one electric motor, which is configured to move the roller conveyor along guides and/or is also configured to perform the function of the guides.

In accordance with further variants that are not a part of the present invention, the actuator system <NUM> comprises (in particular, is - coincides with) the actuator system <NUM>. In these cases, in particular, the actuator system <NUM> (i.e. the actuator system <NUM>) comprises a connection element (for example a pin, a hook, or other elements which perform the same function - known per se and not illustrated) to be connected to the roller conveyor <NUM>.

The connection element allows the actuator system <NUM> to move the roller conveyor <NUM> along the guides <NUM> (in particular, linear guides), which are part of the device <NUM>.

The actuator system <NUM> is configured to move the rollers <NUM> to the conveying path P (and to the work position - defined below), along respective transfer paths having at least one common segment.

The rollers <NUM> define a conveying plane CP, along the conveying path P, and the actuator system <NUM> moves the rollers <NUM> from a rest position, outside of the conveying plane, to a work position, substantially arranged in the conveying plane.

Advantageously, but not necessarily, the actuator system <NUM> comprises an electric motor <NUM> which is mechanically connected to the rollers <NUM> of the extension device <NUM>.

In particular, the rollers <NUM> each have a respective shaft <NUM>. More particularly, the shafts <NUM> of the rollers <NUM> comprise ends <NUM> which axially protrude from the rollers <NUM>. These ends <NUM> serve the function of mechanically coupling the rollers <NUM> to the actuator system <NUM>, which allows the movement thereof (in particular, along the respective transfer path).

Advantageously, but not necessarily, the actuator system <NUM> comprises at least one elongated transmission element provided with seats where the shafts <NUM> of the rollers <NUM> are inserted, in particular inside each of which an end <NUM> of a shaft <NUM> is inserted. More precisely, the actuator system <NUM> comprises two elongated transmission elements provided with seats where the shafts <NUM> of the rollers <NUM> are inserted, in particular inside each of which an end <NUM> of a shaft <NUM> is inserted.

According to some non-limiting embodiments (such as that illustrated in <FIG>), the elongated transmission elements are chains <NUM> provided with (as the seats) hollow pins <NUM>, inside each of which an end <NUM> of a shaft <NUM> is inserted. In other words, the rollers <NUM> are connected (pivoted) to the chains <NUM>, i.e. the chains <NUM> support the rollers <NUM>. Accordingly, the chains <NUM> are configured to (at least partially) support the rollers <NUM>.

According to some embodiments that are not a part of the present invention, the aforementioned connection element couples (at least) one roller <NUM> of the roller conveyor <NUM> to the elongated transmission elements, in particular to the chains <NUM>.

Advantageously, but not necessarily, (at least) the roller <NUM> closest to the rollers <NUM> is connected (pivoted) to the elongated transmission element (in particular, to the elongated transmission elements; more particularly, to the chains <NUM>). More precisely, the (each) elongated transmission element is provided with seats, inside (at least) one of which the shaft <NUM> of (at least) one of the rollers <NUM> is inserted, in particular the one closest to the second rollers <NUM>.

Alternatively or additionally, the elongated transmission element (in particular, the elongated transmission elements; more particularly, the chains <NUM>) is connected directly to the roller conveyor <NUM>. In this way, the roller conveyor <NUM> (together with all the rollers <NUM>) is moved by the elongated transmission element (i.e. from the chains <NUM>).

Accordingly, when the chains <NUM> move (through the motor <NUM>), (at least) the roller <NUM> closest to the rollers <NUM> pushes (or pulls) the roller conveyor <NUM> along the guides <NUM>. In other words, through the connection element, the movement of the rollers <NUM> is mechanically constrained to the movement of the chains <NUM>, and therefore of the rollers <NUM> and the actuator system <NUM>. In this way, as the rollers <NUM> and (at least) the roller <NUM> closest to the rollers <NUM> are mounted (pivoted) on the same chains <NUM>, the distance travelled by the roller conveyor <NUM> (pushed (at least) by the roller <NUM> closest to the rollers <NUM>) along the direction D parallel to the conveying path corresponds exactly to the (linear) distance travelled by the rollers <NUM> to extend the conveying device <NUM>.

According to some non-limiting embodiments, the chains <NUM> can be replaced by any element capable of transmitting the motion of the actuator system <NUM> to the rollers <NUM> (such as for example a belt - which can be toothed or not, a conveyor band, a sleeve, etc.).

The roller conveying device <NUM> comprises an actuator system <NUM> configured to make the rollers <NUM> arranged along the conveying path P rotate on themselves. In particular, the expression "make the rollers <NUM> arranged along the conveying path P rotate on themselves" means (as shown in <FIG>) that the actuator system <NUM> is configured to make at least part of the rollers <NUM> arranged along the conveying path P rotate on themselves (each one around its own longitudinal axis). In other words, the conveying device <NUM> comprises an actuator system <NUM> which rotates the rollers <NUM> arranged along the conveying path P.

In this way, by reducing the distance between two consecutive driven rollers, it is possible to reduce the size of the minimum format that the conveying device <NUM> is able to carry. Furthermore, the conveying device <NUM> is decidedly simpler (constructively and operationally less costly) compared to the state of the art and also allows the articles AR to be handled in a more delicate way (the articles AR do not undergo tugs).

Advantageously, but not necessarily, the actuator system <NUM> is configured to make (at least) most of the rollers <NUM> arranged along the conveying path P rotate on themselves.

In some non-limiting cases, the actuator system <NUM> is configured to make all the rollers <NUM> arranged along the conveying path P rotate on themselves.

According to some non-limiting embodiments, not shown, the actuator system <NUM> is configured to make all the rollers <NUM> arranged along the conveying path P rotate on themselves, except for the roller <NUM> (or the rollers <NUM>) arranged along the conveying path P and furthest away from the roller conveyor <NUM>.

In some non-limiting cases, this roller <NUM> (or these rollers <NUM>) not moved by the actuator system <NUM> is (are) idle.

In other non-limiting cases, this roller <NUM> (or these rollers <NUM>) not moved by the actuator system <NUM> is (are) moved indirectly by the actuator system <NUM>, in particular by means of a (flat or toothed) belt. In these cases too, therefore, the actuator system <NUM> is configured to make all the rollers <NUM> arranged along the conveying path P rotate on themselves.

Advantageously, but not necessarily, the rollers <NUM> of the extension device <NUM> each have, at least at one end (in particular at the ends <NUM> of the shaft <NUM>), a number of bushings <NUM> (in particular, toothed bushings).

Advantageously, but not necessarily, the actuator system <NUM> comprises an elongated transmission element, which is configured to transmit, through coupling to the bushings <NUM>, a rotary motion to the rollers <NUM> arranged along the conveying path P.

In particular, the elongated transmission element (of the system <NUM>) comprises (is) a locular motorized element, which transmits, through mechanical coupling to the toothed bushings <NUM>, a rotary movement to the rollers <NUM> arranged along the conveying path P.

According to the non-limiting embodiments illustrated in <FIG>, the locular element is a motorized toothed belt <NUM>. In particular, the motorized toothed belt <NUM> is connected to the toothed bushings <NUM> of the rollers <NUM> located on the conveying path P through a shape coupling. In other words, the teeth of the motorized toothed belt <NUM> (in particular, arranged with the long side substantially parallel to the conveying path P) transmit a rotary motion to the rollers <NUM> arranged along the conveying path P.

The extension device <NUM> comprises a plurality of rollers <NUM>, a first part of which is arranged along the conveying path P and a second part is arranged outside the conveying path P. In these cases, the intermediate length of the path P will be less than that shown in <FIG> and greater than that shown in <FIG>.

According to some non-limiting embodiments (such as that illustrated in <FIG>), the motorized toothed belt <NUM> transmits the rotary motion exclusively to the rollers <NUM> of the extension device which are located along the conveying path P. This is because, since the long side of the motorized toothed belt <NUM> is substantially parallel to the conveying path P, the actuator system <NUM> moves (at least some of) the rollers <NUM> from the work position (along the conveying path P), in contact with the motorized toothed belt <NUM>, to the rest position (outside the conveying path P), not in contact with the motorized toothed belt <NUM>. Consequently, the rollers <NUM> in the rest position, as they are not in contact with the toothed belt <NUM>, do not rotate on themselves, whereas the rollers <NUM> in the work position, as they are in contact with the toothed belt <NUM>, rotate on themselves.

According to some non-limiting embodiments (such as that illustrated in <FIG>), the first actuator system <NUM> moves the rollers <NUM> by means of a "shutter" operation. In other words, the chain <NUM> supporting the rollers <NUM> and moved by the actuator system <NUM> has a first portion parallel and adjacent to the conveying path P and a second portion, adjacent to the first portion, which moves away from the conveying path P.

Advantageously, but not necessarily, the roller conveying device <NUM> comprises an actuator system <NUM> configured to make the rollers <NUM> of the roller conveyor <NUM> rotate on themselves.

In particular, the rollers <NUM>, similarly to the rollers <NUM>, each have a respective shaft <NUM>, which is equipped with at least one end <NUM> of a bushing <NUM> (in particular, a smooth bushing). More particularly, the actuator system <NUM> comprises a motorized belt <NUM> which transmits a rotary motion through coupling (friction) with the (smooth) bushing <NUM> of each roller <NUM> of the roller conveyor <NUM>.

As an alternative to the smooth bushings <NUM> moved by friction by the belt <NUM>, it is possible to use any element capable of transmitting a rotary motion to the rollers, which can be either a common element (e.g., a toothed belt, a chain, etc.), or an independent element (e.g., electric motors for each individual roller or for restricted groups of rollers).

Advantageously, but not necessarily, the pitch between the rollers <NUM> and/or <NUM> arranged along the conveying path P is substantially constant, in particular it is fixed. In the ceramic industry for the production of articles AR (tiles), the fact that the rollers are at a substantially constant distance from one another allows the articles AR (pressed, but still unfired tiles) to be conveyed, reducing the risk of causing cracks and/or fractures due to an excessive distance between the rollers <NUM>, <NUM>. The constant pitch between the rollers allows the weight of the articles AR to be evenly distributed on the rollers, favouring the conveying thereof without shocks.

In accordance with the second aspect of the present invention, there is provided a connection machine connecting a loading unit to a discharge unit according to claim <NUM>.

According to some non-limiting embodiments (such as that illustrated in <FIG>), the connection machine <NUM> is arranged between a ceramic press <NUM> (a loading unit) and a conveyor line <NUM> (a discharge unit). In particular, the machine <NUM> comprises a roller conveying device <NUM>.

According to some non-limiting embodiments (such as those illustrated in <FIG>), the connection machine <NUM> is a machine for connecting a press <NUM>, provided with moulds <NUM>, for the production of ceramic industry articles AR, to a conveyor line for such articles AR, in particular for tiles, more particularly unfired tiles.

Advantageously, but not necessarily, the machine <NUM> comprises a rotation unit <NUM> (a treatment unit) for the rotation of the articles AR (pressed, unfired tiles) to be conveyed from the outlet of the ceramic press <NUM>. In particular, the machine <NUM> also comprises a discharge roller conveyor <NUM> (provided with rollers) configured for sorting out the rotated articles AR. According to some non-limiting embodiments, not shown, the roller conveyor <NUM> is defined as the conveying device <NUM> described in accordance with the first aspect of the present invention.

According to some non-limiting embodiments (such as that illustrated in <FIG>), the articles AR (tiles), whatever the format, come out of the ceramic press <NUM> (by means of a pusher, not shown), are conveyed by the roller conveying device <NUM> inside the rotation unit <NUM>. The rotation unit <NUM> makes the article AR (or each article AR) located therein rotate on itself (tip over). Once the article AR has been rotated, the rotation unit <NUM> conveys the article AR onto the discharge roller conveyor <NUM>, which in turn conveys it to the conveyor line <NUM>.

Advantageously, but not necessarily, the rollers of the discharge roller conveyor <NUM> and the rollers <NUM>, <NUM> of the roller conveying device <NUM> move at adjustable angular speeds. In particular, the rollers of the discharge roller conveyor <NUM> move with lower angular speeds compared to those of the rollers <NUM>, <NUM> of the roller conveying device <NUM>. In this way, it is possible to use the discharge roller conveyor <NUM> as a temporary magazine (buffer) for the smaller formats.

According to some non-limiting embodiments, the rollers of the discharge roller conveyor <NUM> have different angular speeds, in particular decreasing speeds. In this way, the rollers of the discharge roller conveyor <NUM> allow a progressive slowing down of the articles AR present on the discharge roller conveyor <NUM>, thereby improving its capacity as a temporary magazine (buffer) for the smaller formats.

Advantageously, but not necessarily, in order to easily allow maintenance and format changes (which require space in front of the ceramic press <NUM>), the connection machine <NUM> comprises a disengagement system <NUM> configured to move the roller conveying device <NUM> from an engagement position (shown in <FIG> and <FIG>) to a disengagement position (shown in <FIG>).

In particular, the engagement position is substantially horizontal and the disengagement position is substantially vertical.

In particular, the first disengagement system <NUM> is configured to move the roller conveying device <NUM> by means of a rotation around an axis A1 transverse to the conveying path A1. More particularly, the rotation around the axis A1 takes place through articulated connections (such as those shown in <FIG>) between the disengagement system <NUM> and the conveying device <NUM>.

The overall size reduction described above is implemented with particular ease by reducing the length of the roller conveying device <NUM> (i.e. by moving the roller conveyor <NUM> via the actuator system <NUM> away from the ceramic press <NUM>). In this way, the roller conveying device <NUM> is freed from the hindrances <NUM> which are generally caused by the ceramic press and the protections (partitions, screens, etc.) necessary to safeguard the operators, thus allowing the rotation of the roller conveying device <NUM>.

Advantageously, but not necessarily, in order to easily allow maintenance and machine movements, the connection machine <NUM> comprises a disengagement system <NUM> configured to move the discharge roller conveyor <NUM> from an engagement position (shown in <FIG> and <FIG>) to a disengagement position (shown in <FIG>). In particular, the engagement position is substantially horizontal and the disengagement position is substantially vertical.

In particular, the disengagement system <NUM> is configured to move the discharge roller conveyor <NUM> by means of a rotation around an axis A2 transverse to the conveying path P. More particularly, the rotation around the axis A2 takes place through articulated connections (such as those shown in <FIG>) between the disengagement system <NUM> and the discharge roller conveyor <NUM>.

In accordance with the third aspect of the present invention, there is provided a plant <NUM> for the production of articles AR according to claim <NUM>, comprising a roller conveying device <NUM> as described above in accordance with the first aspect of the present invention. In particular, the plant <NUM> comprises a connection machine <NUM> in accordance with the second aspect of the present invention.

According to some non-limiting embodiments (such as those illustrated in <FIG>), the plant <NUM> is a plant for the production of ceramic industry articles AR, in particular for the production of tiles, more particularly unfired tiles.

In accordance with the fourth aspect of the present invention, there is provided a method to extend a roller conveying device according to claim <NUM>.

Advantageously, but not necessarily, the method comprises a movement step, during which the actuator system <NUM> moves the roller conveyor <NUM> by a certain distance DC in the direction D substantially parallel to the conveying path.

The method comprises an extension step, during which the actuator system <NUM> moves the rollers <NUM> so as to vary the length L of the conveying path P (and of the conveying device <NUM>) by changing, downstream or upstream of the roller conveyor <NUM>, the number of rollers <NUM> along the conveying path P.

According to some non-limiting embodiments (as shown in <FIG>), during the extension step, the actuator system <NUM> also moves the rollers <NUM> (through the aforementioned connection element).

According to further non-limiting embodiments, not shown, the method comprises a movement step, during which the (independent) actuator system <NUM> moves the roller conveyor <NUM> by a certain distance DC in the direction D substantially parallel to the conveying path. Advantageously, but not necessarily, during the extension step, the actuator system <NUM> moves the rollers <NUM> by a distance substantially equal to the distance DC.

In these cases, advantageously, but not necessarily, particularly during a format change (replacement of the mould with a different size mould), the extension step and the movement step take place substantially simultaneously. This allows time saving.

According to some embodiments, not shown, the roller conveyor <NUM> is downstream of the extension device <NUM>; accordingly, the number of rollers <NUM> is modified downstream of the roller conveyor <NUM>.

According to some non-limiting embodiments (such as that illustrated in <FIG>), the direction D is opposite to the discharge roller conveyor <NUM>. In other words, the roller conveyor <NUM> is moved in direction D opposite to the flow of the articles AR (which goes from the ceramic press <NUM> to the conveyor line <NUM>).

According to some non-limiting embodiments, the method comprises a step, prior to the extension step, wherein the distance DC by which the actuator system <NUM> must move the extension device <NUM> (in particular, the rollers <NUM>; additionally or alternatively, the rollers <NUM>; more precisely, the elongated transmission element) is set, particularly by means of a software.

According to further non-limiting embodiments, the method comprises a step, prior to the extension and movement steps, wherein the distance DC, by which the actuator system <NUM> and the actuator system <NUM>, respectively, independently move the extension device <NUM> (in particular, the rollers <NUM>; more precisely, the elongated transmission element) and the roller conveyor <NUM>, is set, particularly by means of a software.

According to some non-limiting embodiments, the distance DC is set directly, i.e. by selecting the distance DC via a human-machine interface (HMI).

According to other non-limiting embodiments, the distance DC is set indirectly, i.e. by selecting the number of rollers <NUM> to be added to the conveying path P downstream of the roller conveyor <NUM>, or by selecting the format change. In the latter case, the roller conveying device <NUM> automatically processes (via a control unit) the optimal number of rollers to be added/removed to/from the conveying path P.

According to some non-limiting embodiments (such as those illustrated in the attached figures), when there is a change in the number of rollers <NUM> added to the conveying path P by the extension device <NUM>, there is a corresponding suitable movement of the roller conveyor <NUM> along the guides <NUM>, which is generated by the actuator system <NUM>.

Claim 1:
A roller conveying device (<NUM>) to convey articles along a conveying path (P) with a variable length (L); the conveying device comprising:
a roller conveyor (<NUM>), which is provided with a plurality of first rollers (<NUM>) and is configured to convey the articles along at least one segment of the conveying path (P);
an extension device (<NUM>) provided with second rollers (<NUM>);
at least a first actuator system (<NUM>) to move at least part of the second rollers (<NUM>) so as to vary the length (L) of the conveying path (P) and of the roller conveying device (<NUM>) by changing, downstream or upstream of the roller conveyor (<NUM>), the number of second rollers (<NUM>) along the conveying path (P);
a second actuator system (<NUM>) configured to make the second rollers (<NUM>) arranged along the conveying path (P) rotate on themselves; wherein the first rollers (<NUM>) define a conveying plane (CP);
the first actuator system (<NUM>) being configured to move at least part of the second rollers (<NUM>) between a rest position on the outside of the conveying plane (CP) and a work position substantially arranged on the conveying plane (CP); wherein the first actuator system (<NUM>) is configured to move the second rollers (<NUM>) to the conveying path (P) and to the work position along respective transfer paths having at least one common segment;
a third actuator system (<NUM>), which is configured to move the roller conveyor (<NUM>) in a direction (D) that is substantially parallel to the conveying path (P);
characterized in that the third actuator system (<NUM>) is an independent actuator system, separated from the first actuator system (<NUM>).