Technical field

This invention relates to a device and a method for releasing rod-shaped articles of the tobacco industry onto an endless conveyor. Background art

In the tobacco industry it is normal practice to transfer rod-shaped articles onto an endless conveyor defined by a belt or band provided with a succession of seats transverse to the feed direction of the conveyor in such a way as to feed individual rod-shaped articles transversely one after the other.

The conveyor belt has an upper operating section which passes underneath a plurality of releasing units and whose seats face upwards in order to receive respective rod-shaped articles. The releasing units each have a plurality of feed channels (commonly known as "veins") running side by side and each associated with a respective transfer member disposed at an outlet section of the feed channel. The feed units receive the rod-shaped articles directly from one or more hoppers above them and into which a mass of articles is fed.

In order to be able to release the articles into the seats in a controlled manner, the transfer members are driven in such a way as to release one article at a time at a rate that is suitably synchronized with the other transfer members so as to fill all the seats on the conveyor in a controlled manner. During machine operation, one or more of the releasing units may be subject to malfunctions, caused for example by an interruption in the flow of articles in one or more of the veins or on account of a fault in some of the transfer members or for any other reason.

In this situation, in order to make up for the malfunctioning releasing units failing to feed the articles, it is common practice to provide one or more additional releasing units, which normally remain idle and are activated only in the event of a malfunction of the other units, so that all the seats on the conveyor can resume being filled. In other words, the compensation mechanism provided is based on the numerical redundancy of the releasing units, meaning that the number of releasing units provided is in excess of that strictly necessary for machine operation.

A machine structure of this kind has some inherent disadvantages, however.

In particular, in order to be ready to come into operation, the normally idle redundant units are preloaded with articles ready to be released which means that if they remain inactive for extended periods of time, there is the risk that the properties of these articles will deteriorate and the articles will no longer be suitable for making marketable products.

Moreover, a solution aimed at overcoming this problem would, on the contrary, involve introducing complex machine control mechanisms intended to periodically vary the units that remain idle so as to create a "rotational" redundancy system whereby each of the releasing units would come into operation in turn (according to a rotation program). It is obvious that a system of this kind would inevitably lead to problems connected with the complexity of machine control.

Aim of the invention

In this context, the basic technical purpose of this invention is to provide device and a method for releasing rod-shaped articles of the tobacco industry onto an endless conveyor to overcome the above mentioned disadvantages of the prior art.

More specifically, this invention has for an aim to provide a device and a method for releasing rod-shaped articles of the tobacco industry onto an endless conveyor and capable of improving control over the process of filling the endless conveyor in the event of malfunctions. Brief description of the drawings

The invention is described below with reference to the accompanying drawings, which illustrate a non-limiting embodiment of it, in which:

- Figure 1 represents a releasing device according to this invention in the context of installation in a machine of the tobacco industry;

- Figure 2 is an enlarged view of a detail of the device of Figure 1 ;

- Figure 3 is a further enlarged view of a detail of the view of Figure 2;

- Figure 4 represents a sequence of steps of a first embodiment of a releasing method implemented by the releasing device according to this invention, under normal operating conditions;

- Figure 5 represents a sequence of steps of a first embodiment of a releasing method implemented by the releasing device according to this invention, during a compensating routine consequent upon a malfunction;

- Figure 6 represents a sequence of steps of a second embodiment of a releasing method implemented by the releasing device according to this invention, under normal operating conditions;

- Figure 7 represents a sequence of steps of a second embodiment of a releasing method implemented by the releasing device according to this invention, during a compensating routine consequent upon a malfunction.

The numeral 1 in the accompanying drawings denotes in its entirety a device according to this invention for releasing rod-shaped articles of the tobacco industry onto an endless conveyor.

The device 1 is installed in a machine for making and/or packaging smoking articles and is designed to release rod-shaped articles such as, for example, cigarette or filter segments.

For convenience, the articles are not illustrated in the accompanying drawings, whilst the components of the device used for conveying and transferring the articles are shown in detail. Detailed description of preferred embodiments of the invention

Looking in more detail, the device 1 comprises two juxtaposed releasing units 2, as shown in Figure 1 . Each releasing unit 2 is provided at the bottom of it, with a plurality of feed channels 3 (or "veins") extending at least partly vertically and running side by side and being twenty in number for each unit 2. The feed channels 3 have respective upper stretches which are divergent and respective lower stretches which are parallel and vertical (Figure 2). Each feed channel 3 has, associated with it, a transfer member 4 disposed at an outlet section at the bottom of the feed channel 3 (Figures 2 and 3). At the top of it, each releasing unit 2 is provided with a hopper 5 for containing a mass of articles and connected or connectable to a feed unit (not illustrated because it is of known type) for feeding a plurality of articles: for example, a machine for making the articles or a unit for emptying trays that are full of the articles. The feed channels 3 extend from the bottom of the hopper 5.

As will become clearer as this description continues, there may, without departing from the scope of this invention, be two or more releasing units and each unit may have one or a plurality of feed channels.

Also, in an embodiment, all the releasing units 2 have the same number of feed channels 3. The number may, however, vary from one releasing unit 2 to another.

Under the releasing units 2, or in any case in a spatial relationship with the releasing units 2 suitable for the purpose, there is an endless conveyor 6 - that is to say, a looped conveyor belt, band or chain - having an (upper) operating branch 6a provided with a succession of receiving seats 7 disposed in such a way that receiving seats 7 of the conveyor 6 are aligned with respective transfer members 4 of the releasing units 2.

The operating branch 6a of the conveyor 6 travels along a feed direction "A" and the releasing units 2 are disposed in succession along the feed direction "A".

Each transfer member 4 comprises a rotary element (in the form of a roller, for example) mounted rotatably about a respective horizontal axis of rotation and having a gripping portion 4a rotatable between a gripping position, where it receives an article from the respective feed channel 3, and a releasing position, aligned with a respective receiving seat 7 of the conveyor 6 to release the article into the receiving seat 7.

The device 1 also comprises drive means acting on the transfer members 4 to release from each transfer member 4 a sequence of respective articles at a predetermined rate (or frequency/pace) in such a way that each article released from the transfer members 4 is received into a respective receiving seat 7 of the conveyor 6.

Advantageously, the device 1 also comprises a control unit (also not illustrated), connected to the drive means to adjust the rate at which the articles are released from the transfer members 4.

More specifically, in the event of malfunctioning or stopping of at least one of the releasing units 2, the control unit is configured to activate a compensating routine whereby at least one of the functioning releasing units 2 (that is to say, of those that remain functional, other than the malfunctioning one) is operated at a faster rate and/or in a modified sequence compared to normal operating conditions, that is to say, compared to operating conditions where none of the releasing units 2 is malfunctioning or has stopped, so as to compensate for the smaller number of functioning releasing units 2.

Preferably, the compensating routine activated by the control unit entails operating each of the functioning releasing units 2 at a modified rate and/or in a modified sequence compared to normal operating conditions.

The term "rate" is used to mean the number of articles released per unit time by the transfer members 4 of the same releasing unit 2, while the term "sequence" also indicates the distribution over time of the releasing actions performed by the different transfer members 4 of the same releasing unit 2 (since the temporal sequence of the releasing actions performed by the transfer members 4 may be intercalated, alternated, reversed or, more generally speaking, varied compared to the situation under normal operating conditions).

In an advantageous embodiment of the invention, the transfer members 4 of each releasing unit 2 can be driven and controlled independently of the transfer members 4 of the other releasing units 2.

This may be achieved by configuring the unit to control the drive means in such a way as to operate the transfer members 4 of two or more releasing units 2, preferably all the releasing units 2 at the same rate under normal operating conditions, this rate being subsequently variable during the compensating routine.

In a preferred embodiment, the drive means comprise, for each releasing unit 2, a transmission mechanism (not illustrated in detail) connected to a plurality of transfer members 4 of the releasing unit 2, and preferably to all the transfer members 4 of the releasing unit 2, so as to drive the transfer members 4 simultaneously and/or at the same release rate, if necessary with a specific phase relationship to temporally offset the releasing actions performed by the transfer members 4 of the same releasing unit 2.

For example, the transmission mechanism may be a mechanical part comprising a bar applied eccentrically to the transfer members 4 in such a way as to work like a connecting rod for simultaneously moving some or all of the transfer members 4 of the releasing unit 2.

Preferably, the drive means also comprise, for each releasing unit 2, a respective motor or actuator (not illustrated) driven by the control unit independently of the motors or actuators of the other releasing units 2. Advantageously, the control unit is configured to activate all the releasing units 2 under normal operating conditions. That way, under normal operating conditions, all the releasing units 2 are in operation and can work at a release rate that is lower than a respective maximum release rate.

In an embodiment, during the compensating routine, the control unit acts on the drive means to set at least one rotary element 4 of at least one of the functioning releasing units 2 in rotation about its axis at a speed which is higher than the corresponding speed of rotation under normal operating conditions. This rotation speed may be continuous and preferably constant. In such a case, the higher rotation speed is applied in at least one stretch of each rotation cycle of the rotary element.

In a different embodiment, the control unit acts on the drive means to set each rotary element 4 in rotation intermittently about its axis. Under these circumstances, during the compensating routine, the control unit acts on the drive means to set at least one rotary element 4 of at least one of the functioning releasing units 2 in rotation intermittently so that its stop time is shorter than the corresponding stop time under normal operating conditions. By "stop time" is meant the length of time the same transfer member 4 stops for between two successive steps of rotating.

A possible releasing method forming an object of this invention and preferably implemented by the device 1 described above comprises the following steps:

- feeding a plurality of rod-shaped articles of the tobacco industry to a plurality of releasing units 2, each of which has at least one feed channel 3 associated with a respective transfer member 4 disposed at an outlet section of the feed channel 3

- causing an (upper) operating branch 6a of an endless conveyor 6, preferably a conveyor belt, band or chain, to advance under the transfer members 4 in such a way that receiving seats 7 of the conveyor 6 are aligned with respective transfer members 4 of the releasing units 2;

- releasing from each transfer member 4 a sequence of respective articles at a predetermined rate (or frequency/pace) in such a way that each article released from the transfer members 4 is received into a respective receiving seat 7 of the conveyor 6;

- in the event of malfunctioning or stopping of at least one of the releasing units 2, activating a compensating routine whereby the step of releasing the articles from at least one of the functioning releasing units 2 is carried out at a faster rate compared to normal operating conditions, that is to say, compared to operating conditions where none of the releasing units 2 is malfunctioning or has stopped, so as to compensate for the smaller number of functioning releasing units 2.

During the compensating routine, the faster release rate applies to all the functioning releasing units 2 and is preferably the same for all the functioning releasing units 2.

Preferably, the step of releasing the articles from the releasing units 2 is carried out by driving at least some of the releasing units 2, preferably all of the releasing units 2, independently of each other, in particular through respective motor means (for example, electric motors or actuators) controlled independently of each other.

Looking in more detail, under normal operating conditions, the transfer members 4 of the releasing units 2 operate at a first release rate at which the respective articles are released into the receiving seats 7 of the conveyor 6, whereas during the compensating routine, the transfer members 4 operate at a second release rate which is higher than the first release rate.

Moreover, the first and second release rates are lower than the maximum release rate permitted by the transfer members 4.

Furthermore, preferably, during the compensating routine, the feed speed of the conveyor 6 is unchanged compared to normal operating conditions and, still more preferably, it is a constant speed.

Preferably, each feed channel 3 is associated with a respective sensor (not illustrated) to detect possible jamming or incorrect feeding of the articles in the feed channel 3 and, if malfunctioning is detected, the sensor sends to the control unit a respective identification signal relating to the malfunctioning detected. Under these circumstances, the control unit sets to "malfunctioning" the state of the releasing unit 2 associated with that signal (that is to say, comprising the feed channel affected by the fault) and activates the compensating routine.

Figures 4-7 illustrate different embodiments of the method implemented by the releasing device according to the invention.

Figures 4 and 5 show an application example comprising two releasing units 2, each (by way of example) having only one feed channel and hence only one transfer member 4, the two transfer members 4 being spaced from each other by a distance equal to an even number of receiving seats 7 (in Figure 4, the distance is equal to two receiving seats 7).

Looking in more detail, Figure 4 shows a sequence of steps of releasing under normal operating conditions where each transfer member 4 releases one article 100 every two receiving seats 7 moving past thereunder and where the two transfer members 4 perform the releasing action alternately. Figure 5, on the other hand, shows the situation when the compensating routine is activated.

According to the compensating routine, in a situation where the releasing unit 2 downstream suddenly stops releasing articles 100, the other releasing unit 2, upstream, makes up for the interruption by doubling the release rate, which means that by itself it fills all the receiving seats 7 on the conveyor 6. It is evident that an operating logic of this kind can be applied in the same way to releasing units 2 which each have a plurality of feed channels 3. In effect, in such a case, each releasing action performed by a releasing unit 2 corresponds to the simultaneous filling of a number of receiving seats 7 equal to the number of feed channels 3 of the releasing unit 2. In other words, the embodiment illustrated in Figures 4 and 5 is extendable by providing, in the place of each seat 7, a number of seats that is equal to the number of feed channels of each releasing unit 2 (in such a situation, it is preferable, though not necessary, that the releasing units 2 have the same number of feed channels 3, as described above).

Similarly, this operating logic can also be applied when the distance between the two transfer members 4 corresponds to an uneven number of receiving seats 7 on the conveyor 6 (embodiment not illustrated). In such a case, it is obvious that the two transfer members 4 fill all the seats 7 by simultaneously releasing corresponding articles.

Figures 6 and 7 show an application example comprising three releasing units 2, each (by way of example) having only one feed channel and hence only one transfer member 4, the three transfer members 4 being spaced from each other by a distance equal to an uneven number of receiving seats 7 (in Figure 6 the distance is equal to three receiving seats 7).

Looking in more detail, steps 6a-6j show a normal operating condition where each transfer member 4 releases one article 100 every three receiving seats 7 moving past thereunder and where the three transfer members 4 perform the releasing action according to the sequence illustrated (the sequence starts from a transient starting condition associated with an empty conveyor 6).

Steps 7a-7e, on the other hand, show the situation when the compensating routine is activated.

According to the compensating routine, in a situation where the releasing unit 2 further downstream suddenly stops releasing articles 100, the other two releasing units 2, upstream, make up for the interruption by changing the release rate so that one releasing action is performed every two seats 7 that pass thereunder.

In each of the two cases illustrated, the possible presence of receiving seats not filled is due to the unfavourable case of malfunctioning of the releasing unit 2 furthest downstream, which means that seats already left empty cannot be filled, although this is a temporary, transient condition that is corrected within the space of time of advancing just a few receiving seats 7. It is evident that the operating logic illustrated in Figures 4-7 can be extended to any number of releasing units 2, specifically by applying the teachings of the invention and making the different releasing units 2 controllable independently of each other so that the release rate of each of them can be varied independently for the purposes of compensation.

The considerations made with regard to Figure 4-5 also apply to the embodiment of Figures 6-7: that is to say, the possibility of extending the embodiment by providing, instead of each seat 7, a number of seats equal to the number of feed channels of each releasing unit 2 (which release articles onto the conveyor 6 preferably simultaneously).

Moreover, it is evident that this invention can be carried out by applying, in the compensating routine, a different release algorithm (that is to say, different release sequences for some or all of the transfer members) instead of merely increasing the rate, provided always that the compensating logic is intended to fill all the receiving seats of the conveyor even when one or more of the releasing units have stopped on account of a malfunction.

The present invention achieves the preset aims, overcoming the disadvantages of the prior art.

In effect, in the event of malfunctioning of one or more releasing units, the device and method according to the invention allow varying the release algorithm (sequence and/or rate) of the remaining releasing units in order to make up for the smaller number of functioning releasing units without having to provide redundant releasing units which remain idle but, instead, with releasing units which, under normal operating conditions, work at a speed lower than the maximum speed so as to preserve their working life.