The present invention relates to a machine for packing cylindrical articles, and to a group-forming device for forming groups of cylindrical articles.

The present invention may be used to advantage for packing cigarettes, to which the following description refers purely by way of example.

More specifically, the present invention relates to a machine for packing cylindrical articles in the tobacco industry, and which comprises a group-forming device for forming a group of cylindrical articles. The group-forming device in turn comprises a substantially vertical hopper; a conveying device comprising at least one pocket for housing the group of cylindrical articles; and a transfer device for transferring the cylindrical articles from the hopper to the conveying device. The transfer device comprises a push member for pushing a first and at least a second subgroup of cylindrical articles, crosswise to the feed direction, into the pocket at a first and second insertion station respectively; and the second subgroup is inserted, in use, into the pocket on top of the first subgroup to define the group of cylindrical articles.

Examples of machines of the above type for packing cylindrical articles are described in US3707219.

US5590513 describes a cigarette packing machine comprising a group-forming device for forming a group of cigarettes. The group-forming device in turn comprises a substantially vertical hopper housing a mass of downward-fed cigarettes; and a transfer device for transferring a group of cigarettes from the hopper into a folding spindle. And the folding spindle has movable lateral walls for compressing the group of cigarettes.

FR1475759 discloses cigarettes supplied from a hopper to separate stations, where they are fed into pockets of a conveyer, to form successive layers of cigarettes, by means of a pusher. Each group of cigarettes thus formed is ejected from the conveyer by a pusher and passes to a packaging machine. The number of layers of cigarettes in each group invariably equals the number of stations. The cigarettes may be formed into groups of a different number, and there may be three stations at which the conveyer pockets are filled.

Known cigarette packing machines of the above types have the drawback of being unable to satisfactorily pack substantially triangular groups of cigarettes.

In this connection, it is important to note that, being highly unstable, on account of the relative positions of the cigarettes, triangular groups of cigarettes are relatively difficult to handle. To produce packets of triangular groups of cigarettes, therefore, it is essential that means be provided - which are not, on known machines - to maintain the relative positions of the cigarettes, while at the same time adequately preparing the groups for wrapping (normally in a foil wrapping).

It is an object of the present invention to provide a machine for packing cylindrical articles, and a group-forming device for forming groups of cylindrical articles, designed to at least partly eliminate the aforementioned drawbacks, and which at the same time are cheap and easy to produce.

According to the present invention, there are provided a machine for packing cylindrical articles, and a group-forming device for forming groups of cylindrical articles, as claimed in the accompanying independent Claims or in any one of the Claims depending directly or indirectly on the independent Claims.

A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

• Figure 1 shows a schematic front view of a cigarette packing machine in accordance with the present invention;
• Figure 2 shows a view in perspective of a packet of cigarettes producible on the Figure 1 machine;
• Figure 3 shows a schematic top plan view, with parts removed for clarity, of a portion of the Figure 1 machine;
• Figure 4 shows a schematic front view of a portion of the Figure 1 machine;
• Figures 5 and 6 show sections along lines V and VI, respectively, of the Figure 3 portion;
• Figure 7 shows a view in perspective of a detail of the Figure 1 machine;
• Figure 8 shows a view in perspective of an alternative embodiment of the Figure 7 detail;
• Figures 9 to 11 show schematics of a portion of the Figure 1 machine at different operating stages;
• Figures 12 and 13 show top plan views of groups of cigarettes of two further shapes packable on a machine in accordance with the present invention;
• Figures 14 and 15 show sections along lines XIV and XV, respectively, of the Figure 3 portion.

Number 1 in Figure 1 indicates as a whole a machine for packing cylindrical articles, in particular cigarettes 2, to form a packet 3 of cigarettes 2 (Figure 2). With particular reference to Figures 3 and 4, machine 1 comprises a group-forming device 4 for forming a group 5 of cigarettes 2, and which comprises a substantially vertical hopper 6 for housing and feeding a mass of cigarettes 2 downwards to a transfer station 7, a conveyor 8 for feeding group 5 from station 7 along a path P in a given direction A, and a transfer device 9 for transferring cigarettes 2 from hopper 6 to conveyor 8.

Device 9 comprises a number of - in the example shown, two - seats 10 and 11 located at the transfer station, and each for receiving from hopper 6 a respective subgroup 12, 13 of cigarettes 2; each subgroup 12, 13 comprising at least one cigarette 2.

At the bottom, hopper 6 comprises a number of channels 14, along each of which a column 15 of single cigarettes 2 travels, in use. Each seat 10, 11 is located beneath at least one channel 14, and contains a respective number of cigarettes 2 different from the number of cigarettes 2 in the other seat 11, 10. In the embodiment shown, seat 10 is located beneath two channels 14, and houses a subgroup 12 comprising three cigarettes 2; and seat 11 is located beneath four channels 14, and houses a subgroup 13 comprising seven cigarettes 2.

The fact that each seat 10, 11 contains a respective number of cigarettes 2, different from the number of cigarettes 2 in the other seat 11, 10, provides for forming group 5 relatively easily.

Each seat 10, 11 comprises two lateral walls 16, each of which is substantially vertical and has an inner surface 17. And each seat 10, 11 comprises a bottom wall 18 having a substantially horizontal top supporting surface 19 and a substantially horizontal bottom supporting surface 19a connected to each other by a respective substantially vertical surface 19b.

An optional known vibrating member (not shown) is provided at seats 10, 11 to vibrate seats 10, 11 to ensure correct insertion of cigarettes 2 inside seats 10, 11.

Conveyor 8 comprises a belt 10 travelling in direction A and looped about two pulleys (not shown); and at least one pocket 21 fitted integrally to belt 20 to travel along path P in direction A.

With particular reference to Figure 7, pocket 21 comprises two lateral walls 22, each having an inner lateral surface 23; a bottom wall 24 having an inner bottom surface 25; and a top wall 26 having an inner top surface 27. Surfaces 23 are crosswise to the given direction, and slope towards each other so that group 5 assumes a substantially triangular shape inside pocket 21. More specifically, surfaces 23 slope so that the space defined inside pocket 21 by surfaces 23, 25 and 27 tapers downwards.

Pocket 21 comprises a slit 28 crosswise to surfaces 23, substantially parallel to direction A, and defining openings in lateral walls 22 and top wall 26; and a slit 29 crosswise to slit 28 and defining an opening in top wall 26.

With particular reference to Figures 3, 5 and 6, device 4 also comprises a push member 30 for pushing subgroups 12, 13 longitudinally, and crosswise to direction A, through respective insertion channels 31, 32 into pocket 21. Push member 30 comprises two pushers 33 comprising a number of push fingers 33a (some of fingers 33a are shown in Figure 3); and each finger 33a is movable longitudinally, and crosswise to direction A, to push a respective cigarette 2 into pocket 21.

Each channel 31, 32 is located at a respective insertion station 34, 35, and comprises two lateral walls 36, each having an inner surface 37; a bottom wall 38 having an inner bottom surface 39; and a top wall 40 having an inner top surface 41.

Inner top surfaces 41 are designed to exert downward pressure on cigarettes 2 in respective subgroups 12, 13, as subgroups 12, 13 are pushed, in use, towards path P.

Each channel 31, 32 is shaped so that the inner cavity 42 defined by surfaces 37, 39, 41 tapers towards path P, and the cigarettes 2 in subgroup 12, 13 are therefore brought closer together and/or compacted as they travel along relative insertion channel 31, 32 towards conveyor 8.

Channel 32 has one end 43 facing path P at a higher level than a similar end 44 of channel 31, so that, in use, subgroup 13 is inserted into pocket 21 on top of subgroup 12.

It is important to note that the cross sections, parallel to direction A, of cavities 42 vary. More specifically, the respective cross sections, parallel to direction A, of cavities 42 are substantially T-shaped (Figures 5 and 6) at ends 43 and 44, and are substantially L-shaped (Figures 14 and 15) at the opposite ends to ends 43 and 44. This particular design of cavities 42 provides for positioning cigarettes 2 in each subgroup 12, 13 correctly with respect to one another, as cigarettes 2 are fed from hopper 6 to conveyor 8.

With particular reference to Figures 9 to 11, device 4 also comprises a stabilizing device 45 for keeping subgroup 12 positioned correctly inside pocket 21 as pocket 21 travels, in use, along path P between stations 34 and 35. Device 45 has the same structure and operates in the same way as the stabilizing device described in US3642112, to which full reference is made herein. More specifically, device 45 comprises a retaining member 46, which at least partly engages slit 28 to define the top of a portion 47 of pocket 21 housing subgroup 12. And retaining member 46 has a bottom pressure surface 48 for pressing down on subgroup 12.

Device 45 also comprises actuating members (not shown) for moving retaining member 46, in time with pocket 21, along path P from station 34 to station 35 (Figure 9), and, once pocket 21 reaches station 35 (Figure 10), for returning retaining member 46 to station 34 (Figure 11).

Device 4 preferably comprises a known control unit (not shown) for coordinating push member 30 and the actuating members (not shown), so that retaining member 46 begins disengaging the slit when subgroup 13 is at least partly inserted inside pocket 21.

Operation of machine 1 will now be described briefly, as of the instant in which subgroup 12 is correctly positioned inside seat 10.

At this point, push member 30 pushes subgroup 12 through insertion channel 31 into pocket 21; and subgroup 12 is kept positioned correctly inside pocket 21 by retaining member 46, which moves together with pocket 21 from station 34 to station 35.

When pocket 21 reaches station 35, subgroup 13, formed in the meantime inside seat 11, is pushed through channel 32 into pocket 21 and on top of subgroup 12 to form group 5. As subgroup 13 begins engaging pocket 21, retaining member 46 is withdrawn from station 35 to station 34 to disengage slit 28 and avoid interfering with insertion of subgroup 13.

In the above embodiment, group 5 of cigarettes 2 is substantially triangular with its apex facing downwards.

In a further embodiment, group 5 is formed with its apex facing upwards. In which case, hopper 6 is equipped with mechanical fingers (not shown) for selectively closing some of channels 14 to form, inside seats 10 and 11, superimposed layers (not shown) of decreasing numbers of cigarettes 2 (i.e. layers in which the top layer comprises a smaller number of cigarettes 2 than the underlying layer). The pocket 21 of this further embodiment is shown in Figure 8.

Though the above description relates to a packet 3 of ten cigarettes 2, the teachings of the present invention obviously also apply to packets containing a different number of cigarettes 2.

Purely by way of example, Figures 12 and 13 show respective groups 5' and 5" of cigarettes 2 of two further shapes that can be produced and packed in accordance with the present invention. More specifically, group 5' comprises twenty-one cigarettes 2, and group 5" twenty cigarettes 2.

The above embodiments may also obviously be modified to form subgroups 12, 13 comprising a different number of layers of cigarettes 2. More specifically, in an embodiment not shown, to form groups 5" of twenty cigarettes 2, each subgroup 12, 13 comprises three layers of cigarettes 2. In which case, subgroup 12 comprises six, and subgroup 13 fourteen, cigarettes 2.