BACKGROUND ART In cigarette manufacturing and packing plants, a variable-capacity store for packets of cigarettes is interposed between a cigarette packing machine and a cellophaning machine to compensate for any difference between the number of packets of cigarettes produced and the number of packets of cigarettes cellophane-wrapped.

In cigarette manufacturing and packing plants, a variable-capacity store for packets of cigarettes is also interposed between a cellophaning machine and a cartoning machine to compensate for any difference between the number of packets of cigarettes cellophane-wrapped and the number of packets of cigarettes packed into respective cartons.

Currently marketed variable-capacity stores for packets of cigarettes, such as model LL16 marketed by G. D. Societa per Azioni and described in Patent

US4711336, are FILO (First In Last Out) types, i. e. in which the first packets of cigarettes fed into the store are the last to be fed out.

FILO-type variable-capacity stores for packets of cigarettes, however, have the drawback of some of the packets of cigarettes possibly being parked in the store for a prolonged period of time normally incompatible with modern manufacturing processes. Moreover, cigarettes in packets stored for a prolonged period of time with no cellophane wrapping tend to lose their original characteristics (e. g. lose part of their aroma or absorb damp).

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a FIFO-type variable-capacity store for packets of cigarettes, which is cheap and easy to produce and, in particular, is compact and highly reliable.

According to the present invention, there is provided a variable-capacity store for packets of cigarettes; the store being a FIFO type and comprising a conveyor defining a conveying branch for transferring the packets of cigarettes from an input station to an output station; and the conveyor comprising a flexible belt having a conveying surface for supporting the packets of cigarettes along the conveying branch; characterized by comprising stabilizing means associated with the flexible belt and for securing each packet of cigarettes to the flexible belt.

BRIEF DESCRIPTION OF THE DRAWING A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawing showing, schematically, a store for packets of cigarettes in accordance with the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Number 1 in the accompanying drawing indicates as a whole a variable-capacity store for substantially parallelepiped-shaped packets 2 of cigarettes; store 1 is a FIFO (First In First Out) type i. e. wherein the first packets 2 of cigarettes to be fed into store 1 are also the first packets 2 of cigarettes to be fed out of store 1.

Store 1 comprises an input station S1 and an output station S2 arranged in series along a feed path P of packets 2 of cigarettes; input-station S1 receives a succession 3 of packets 2 of cigarettes from an output conveyor of a known packing machine (not shown); and output station S2 feeds a succession 4 of packets 2 of cigarettes to an input conveyor of a known cellophaning machine (not shown).

Store 1 also comprises an endless conveyor 5 for feeding packets 2 of cigarettes along path P. More specifically, endless conveyor 5 comprises a conveying branch 6, which is substantially horizontal (i. e. slopes by no more than 20° with respect to the horizontal), extends between a drum 7, close to input station S1, and

a drum 8, close to output station S2, and feeds packets 2 of cigarettes from input station S1 to output station S2; and a return branch 9 extending between a drum 10, close to output station S2, and a drum 11, close to input station S1.

Conveyor 5 comprises a flexible belt 12 having a conveying surface 13 for supporting packets 2 of cigarettes and which is substantially horizontal (i. e. slopes by no more than 20° with respect to the horizontal) along conveying branch 6. Flexible belt 12 winds about a number of transmission pulleys 14 (shown schematically), some of which are powered to impart motion to belt 12; and belt 12 also winds in respective coils about drums 7 and 8 (conveying branch 6) and about drums 10 and 11 (return branch 9).

A known fixed continuous guide (not shown) extends along conveying branch 6, parallel to path P, is connected to flexible belt 12, and defines a tunnel through which packets 2 of cigarettes are fed, and the bottom wall of which is defined by flexible belt 12. More specifically, the tunnel is the same shape as, and slightly larger in section than, a packet 2 of cigarettes, so as to guide packets 2 of cigarettes along path P.

Each packet 2 of cigarettes is parallelepiped- shaped, is of a length (typically 80 to 100 mm) greater than its width (typically 50 to 60 mm), and is of a width greater than its thickness (typically 15 to 25 mm). To

make the best use of the space inside store 1, packets 2 of cigarettes are conveniently positioned"on edge"on flexible belt 12, as shown in the accompanying drawing.

That is, each packet 2 of cigarettes is positioned with a lateral wall resting on flexible belt 12, so that its thickness is parallel to the traveling direction of flexible belt 12, its length is parallel to flexible belt 12, and its width is perpendicular to flexible belt 12.

In the preferred embodiment shown in the accompanying drawing, flexible belt 12 has a transverse dimension smaller than the length of packets 2 of cigarettes, so as to engage, together with teeth 16, a central portion of each packet 2 of cigarettes, while leaving two lateral portions, on either side of the central portion, of each packet 2 of cigarettes free.

This arrangement makes packets 2 of cigarettes easier to feed in at input station S1 and out at output station S2, by enabling each packet 2 of cigarettes, at input station S1 or output station S2, to be engaged simultaneously by conveyor 5, which engages a central portion of packet 2 of cigarettes, and by a further known conveyor (not shown) for conveying succession 3 or 4, and which engages the lateral portions of packet 2 of cigarettes.

Flexible belt 12 comprises stabilizing means 15 for securing each packet 2 of cigarettes to flexible belt 12 and so preventing jamming caused by packets 2 of cigarettes falling out of position as flexible belt 12

travels along-particularly around bends or when accelerating/decelerating.

Flexible belt 12 comprises a number of teeth 16, which define stabilizing means 15, extend crosswise to the traveling direction of. flexible belt 12, and are equally spaced along the whole of flexible belt 12 with a spacing slightly greater than the thickness of each packet 2 of cigarettes. More specifically, the distance between each two consecutive teeth 16 equals the thickness of a packet 2 of cigarettes plus a value (roughly 5 to 20% of the thickness of a packet 2 of cigarettes) to allow for the production tolerances of both teeth 16 and packets 2 of cigarettes. Each tooth 16 is preferably substantially parallelepiped-shaped, possibly terminating with a truncated-cone-shaped top portion.

Each two consecutive teeth 16 define a gap for housing a respective packet 2 of cigarettes, which is inserted between the two teeth 16 at input station S1, and is withdrawn from the two teeth 16 at output station S2. Insertion/withdrawal of packet 2 of cigarettes between/from two consecutive teeth 16 is made easier by flexible belt 12 winding, at input station S1 and output station S2, about respective transmission pulleys 14, which curve flexible belt 12 and so part the two consecutive teeth 16.

In a further embodiment-not shown, the distance between each two consecutive teeth 16 is slightly greater

than the thickness of N number of packets 2 of cigarettes, so that two consecutive teeth 16 define a gap for housing a group of N packets 2 of cigarettes, which is preferably relatively small and no more than 5 units.

Each tooth 16 has a transverse dimension equal to the transverse dimension of flexible belt 12, and is of a height equal to a fraction (normally 20 to 60%) of the width of a packet 2 of cigarettes. The height of teeth 16 is selected bearing in mind two conflicting factors: the higher teeth 16 are, the better they provide for retaining packets 2 of cigarettes, but at the same time packets 2 of cigarettes are more difficult to load/unload onto/off conveyor 5.

In an alternative embodiment not shown, teeth 16 may be replaced by gripping members, each integral with, and for gripping a respective packet 2 of cigarettes to, flexible belt 12. Each gripping member preferably comprises a pair of movable jaws, each of which is maintained in a gripping position by a spring and is withdrawn from the gripping position by cams at input station S1 and output station S2.

Store 1 also comprises a known regulating unit (not shown) for adjusting the length LI of conveying branch 6 and the length L2 of return branch 9 in complementary manner, so as to adjust the storage capacity of store 1.

More specifically, the positions of drums 8 and 10 are fixed, and the regulating unit moves drums 7 and 11 with respect to respective drums 8 and 10 by the same amount

but in opposite directions.

When drum 7 is moved closer to drum 8, the storage capacity of store 1 is reduced by shortening conveying branch 6 wound about drums 7 and 8; and the surplus flexible belt 12 must obviously be absorbed by lengthening return branch 9, which is done by moving drum 11 away from drum 10 by the same amount but in the opposite direction to that in which drum 7 is moved closer to drum 8.

Similarly, when drum 7 is moved away from drum 8, the storage capacity of store 1 is increased by lengthening conveying branch 6 wound about drums 7 and 8; and the extra flexible belt 12 must obviously be supplied by shortening return branch 9, which is done by moving drum 11 closer to drum 10 by the same amount but in the opposite direction to that in which drum 7 is moved away from drum 8.

In actual use, packets 2 of cigarettes are fed from succession 3 through input station S1 onto conveying branch 6, and are fed by conveying branch 6 to output station S2 where the packets 2 of cigarettes fed first into store 1 are fed to succession 4 and to the input conveyor of the known cellophaning machine (not shown).

In normal operating conditions, the number of packets 2 of cigarettes fed to input station S1 from succession 3 equals the number of packets 2 of cigarettes absorbed from succession 4 at output station S2; and, in the event the number of packets 2 of cigarettes fed to

input station S1 differs from the number of packets 2 of cigarettes absorbed at output station S2, the known regulating unit (not shown) moves drums 7 and 11 with respect to corresponding drums 8 and 10 to adjust the storage capacity of store 1 and so compensate for the difference in the number of packets 2 of cigarettes fed to input station S1 and the number of packets 2 of cigarettes absorbed at output station S2.