Process and device for packaging products, particularly cylindrical products such as cigarettes, or the like, in a wrapping sheet

Abstract: The invention relates to a process and to a device for packaging products, particularly cylindrical products such as cigarettes, or the like, in a wrapping sheet, and involves wrapping an ordered group of cigarettes (S) in a wrapping sheet (2) and forming a first tubular wrapping open at its opposing ends and provided with portions (402, 502, 602, 702) projecting beyond the corresponding sides of the group of cigarettes. The ends of the tubular wrapping are closed by the successive folding of the various flaps or various wings (402, 502, 602, 702) forming the projecting portions against the corresponding side of the group of cigarettes (S). The formation of the tubular wrapping open at its ends is carried out in the feed station (A), while the closing of the open ends is carried out completely in only one of the successive stations (P), the whole being done by means of particular shaping, arrangement and operation of movable folding means (6, 15, 25, 26) and stationary folding means (5, 105, 205, 605) and of the forming wheel (1).

Description: The invention relates to a process and to a device for packaging products, particularly cylindrical products such as cigarettes, or the like, in a wrapping sheet. The process according to the invention comprises the following stages: forming a group of cigarettes with a predetermined number and order corresponding to those in the packed state; combining the group of cigarettes with a wrapping sheet in a predetermined relative position and inserting them into a containing compartment with simultaneous folding of the wrapping sheet into a "C" shape around the sides of the group of cigarettes associated with the closed sides of the containing compartment; forming a tubular wrapping by folding and retaining in position the flaps of the wrapping sheet on that side of the group of cigarettes at the open entrance side of the containing compartment; subsequently closing the open ends of the tubular wrapping by folding wings formed by the terminal portions at the ends of the tubular wrapping projecting beyond the corresponding sides of the group of cigarettes; in which the complete formation of the pack, in other words the complete folding of the wrapping sheet around the ordered group of cigarettes, is executed in two stations only, in other words in the station where the group of cigarettes and the wrapping sheet are fed into the containing compartment and in only one of the subsequent stations, known as the folding station, the pack being completely formed when it leaves the said folding station, the forming of the open tubular wrapping being executed substantially in the feed station and completed during the step of advance, in other words in the initial portion of the step of advance, and the closing on the ends of the tubular wrapping being completed simultaneously for both opposite ends of the tubular wrapping in the subsequent folding station, while in the next step of advance the completely formed wrapping is simply kept closed until the discharge station is reached. The folding station is advantageously the one immediately following the feed station, so that the ordered group of cigarettes is already completely wrapped in the wrapping sheet before the start of the second step of advance. The process provides for the folding of the wrapping sheet to close the open sides in such a way that the flaps or wings are folded in succession with one being superimposed on another, at least partially, starting with the lowest to the outermost, at a speed higher than the speed of elastic return to the substantially unfolded position or to an intermediate position of folding of the said wings or flaps, while the final upper flap or wing is kept in position folded against the corresponding side of the group of cigarettes and against the other lower flaps or wings until the group of cigarettes, wrapped in this way in the wrapping sheet, is discharged. A process of this kind as defined in the precharacterizing part of claim 1, is known from the document GB-A-2101958. The invention aims to further improve the above described process, in such a way that, by means of simple and economically advantageous arrangements it becomes possible to further limit the effects on operating speed, in other words on the pack wrapping time, and consequently to improve the efficiency of the packaging devices, and also to use new materials with differing degrees of elasticity and of recovery, in other words of returning to the initial state after folding. The invention achieves the above objects with a process of the kind described initially and characterized - according to the characterizing part of claim 1 - in that provision is made to leave free at least one peripheral strip for superimposition of an upper flap or wing to be left free on the lower flaps or wings, this peripheral superimposition strip being provided on a directly adjacent side next to or facing the subsequent upper flap or wing, in other words a part of the flap which is folded into position first, the lower wing or flap being kept in the folded position only until the upper folding wing or flap is at least partially superimposed on to the free superimposition strip. The invention also relates to a device for the application of the said process, which comprises: means for forming an ordered group of cigarettes; means for feeding the said group together with a wrapping sheet into a containing compartment open at least at one entry side and at two sides transverse with respect to it; means for conveying the said containing compartment; movable and/or stationary folding means which are distributed along the path of the compartment for containing the group of cigarettes to be packed and the associated wrapping sheet, these means being designed to fold the wrapping sheet around the group of cigarettes to form a first tubular wrapping and subsequently to close the open ends of the said tubular wrapping. the movable and/or stationary folding means being provided only in the feed station and in only one of the subsequent stations, which is a folding station for completing the packaging wrapper, and which is preferably the station immediately following the feed station. A device of this kind is also known from the said document GB-A-2101958. According to the invention, in a device of this kind, the folding means are shaped in such a way with respect to the flaps or wings and/or are operated in such a way that they stop at a certain distance from a free edge of the said flaps or wings, leaving free a partial or complete strip for the superimposition of the subsequent flap or wing and of the corresponding folder, on that side which is reached first by the folder of the said subsequent wing or flap, the folding means and the operating and synchronizing means being made in such a way that the folding means of the lower wings or flaps and those of the wings and flaps directly above do not interfere with each other, while means are provided which advance the start of the folding movement of the folding means of the upper wing or flap with respect to the return movement of the folder of the flap or wing immediately below, this advance corresponding to the movement required for the superimposition of the said upper flap or wing on the free peripheral superimposition strip of the lower flap or wing. According to a further improvement, the folding means are made in such a way that they are disposed in a stand-by position directly next to the wings or flaps of the wrapping sheet which have not yet been folded, or are brought into this position during the idle or waiting time of these or of other folders, and with the folding edge substantially aligned and/or coinciding with the predetermined folding line. In a preferred embodiment, the wrapping sheet is wrapped in a tubular form around the group of cigarettes, along an axis perpendicular to the direction of transport, while the open side of the containing compartment is orientated parallel to the direction of transport or at a tangent and/or secant to the said direction of transport. In this case, at least one stationary folder and at least one tangential movable folder are provided in the station for feeding the group of cigarettes into the containing compartment, and are disposed opposite each other with respect to the advance of the containing compartment, the tangential movable folder being capable of being driven alternately forwards and backwards, in the direction of advance of the containing compartment or in a direction tangential to the path of advance and transverse with respect to the flap of the wrapping to be folded, with the provision of means of synchronized activation of the reciprocating motion of the tangential folder with the advance of the containing compartment and means of limiting the advance and return movements of the movable folder, these means being made in such a way that the movement of advance takes place in the direction of advance of the containing compartment, and is advanced to such an extent with respect to the step of advance of the said compartment that the folder assumes a stable relative position with respect to the free edge of the folded flap, forming a front peripheral strip which is transverse with respect to the step of advance of the containing compartment, this strip being designed to be partially inserted for a certain distance under the stationary folder and under the part of the flap folded by it, before the said movable folder starts its return movement in the direction opposite the direction of advance of the containing compartment. In the folding station, movable means for folding the projecting end portions of the tubular wrapping are provided for each open end of the tubular wrapping, the end portions comprising at least one pair of first wings opposite each other and orientated tangentially to the direction of advance or in the direction of advance of the containing compartment, and at least two further, second wings opposite each other, joined at their ends to the two tangential wings and orientated transversely, preferably perpendicularly, with respect to the said tangential wings and to the direction of advance of the containing compartment, the movable folders of the first wings consisting of a surface which can oscillate about an axis coinciding with the folding line, in other words with the edge of the corresponding side of the group of cigarettes, from a position in which it is substantially aligned with and externally superimposed on the said wings in the unfolded state to the folded position of the wings, in which the folding surface which can oscillate is turned over against the corresponding side of the group of cigarettes, and the folders of the second wings consisting of two blades opposite each other and with a folding edge movable to a position coinciding with the folding line of the said second wings, in other words with the corresponding edge of the side of the group of cigarettes, these folding blades being capable of being driven with a sliding motion parallel and tangential to the plane containing the corresponding side of the group of cigarettes, one blade being driven in a direction opposite that of the other, and the blades being driven alternately, so that each carries out a folding movement in which the folding blades are at least partially superimposed on the corresponding side of the group of cigarettes and a return movement to the rest and/or stand-by position. The invention also relates to other characteristics which further improve the process and the device described above and which form the subject of the dependent claims. The particular characteristics of the invention, and the advantages derived therefrom, will be more clearly understood from the description of some preferred embodiments, illustrated by way of example and without restriction in the attached drawings, in which: Fig. 1 is a schematic front view of a forming wheel provided according to the invention; Fig. 2 is a schematic view in the direction of feed of the group of cigarettes into the containing compartment of a forming wheel; Fig. 3 is a schematic illustration of the transmission and drive system for synchronizing the steps of advance of the forming wheel with the drive of the folding means; Fig. 4 is a schematic axonometric view of the oscillating blades for folding the radial flaps on the open ends of the tubular wrapping on both ends of the group of cigarettes; Fig. 5 shows the transmission means for the synchronized operation of the oscillating blades; Figs. 6 and 7 show the means of operating the folders for the flaps on the ends of the tubular wrapping, which are orientated tangentially to the direction of advance; Fig. 8 is a view of a folder with the supporting bar, the oscillating drive shaft and the elbow joint end; Fig. 9 is a view of the front radial side, transverse with respect to the direction of transport, of the group of cigarettes between the folders of the flaps tangential to the direction of advance; Figs. 10 to 13 are schematic views of four stages of folding of the wrapping sheet for the formation of a tubular wrapping; Figs. 14 to 19 show, schematically and in relation to only one end of the ordered group of cigarettes, the stages of the closing of the tubular wrapping on the said end; Figs. 20 to 23 are perspective and more schematic views of the stages of folding the projecting flaps of the tubular wrapping as shown in Figs. 14 to 20; Fig. 24 shows the wrapped group of cigarettes at the point where it is released from the folding station and in combination with means for keeping the folded flaps in the folded state; Figs. 25 to 28 show some stages of the folding of the projecting ends of the tubular wrapping for closing the ends of the wrapping according to a variant embodiment of the invention. With reference to Figures 1 to 9, a cigarette packing machine comprises a conveyor drum 1, known as a forming wheel, which is supported rotatably about its own axis on a shaft 301 from which it projects. The forming wheel 1 has a plurality of peripheral radial compartments 101, each of which can contain a group of cigarettes S together with a wrapping sheet 2 for the said group of cigarettes. The containing compartments 101 are formed by axially coinciding recesses of rectangular shape, corresponding to that of the wrapping of the group of cigarettes, these recesses being made in two adjacent discs 201 which form the sides of the forming wheel 1. The containing compartments 101 are distributed at equal angular intervals along the circumference of the forming wheel 1 and the wheel is made to rotate in steps with an angular size corresponding to the angular distance between the individual containing compartments 101. In the central part of the wheel, between the two discs 201, there is a pusher and guide unit indicated overall by the number 3, which has an expelling pusher 103 and a guide 203 on each of its diametrically opposite sides. The expelling pusher 103 and the guide 203 can be driven so that they slide in diametrically opposite directions and interact with the group of cigarettes S together with the sheet 2 in the feed station A and with the wrapped group of cigarettes in the wrapping sheet 2 in the discharge station E on the diametrically opposite side. The group of cigarettes S has a predetermined number of cigarettes with an ordered disposition corresponding to that which the cigarettes are intended to have in the packed state. The group of cigarettes S is orientated with the axis of the cigarettes parallel to the axis of the forming wheel 1, while the ends of the cigarettes are disposed substantially flush with the outer faces of the discs 201. The group of cigarettes is formed by feeding a specified number of cigarettes into housings of predetermined shape associated with a conveyor belt, known as a box conveyor, which is known per se and is not illustrated. Each group of cigarettes is then brought into a transfer station and then into a station for combination with a wrapping sheet. In the station for combination with a wrapping sheet, the group of cigarettes is disposed so that it coincides with the complementary containing compartment 101 and is in front of the open entry side of the compartment, in such a way that it can be introduced into the compartment by movement in a direction transverse with respect to the cigarettes and radial with respect to the forming wheel 1. In the combination station, a wrapping sheet 2 is fed on to the transverse side of the group of cigarettes S, while the sheet and the group of cigarettes are kept in position and then transferred together to the containing compartment 101 by a feed pusher 4 which interacts with the guide 203 and can be moved together with it. At the time of insertion into the containing compartment 101, the wrapping sheet is automatically folded around the sides of the group of cigarettes S inside the containing compartment 101, while axial flaps 102, 202 of the sheet project radially outside the entrance aperture of the said containing compartment 101. The folding of the wrapping sheet 2 around the ordered group of cigarettes at the time of insertion into the containing compartment 101 is caused by two opposing folding edges 105, 205 of a stationary aperture 5 which is provided in a position coinciding with the open side of the containing compartment 101 in the feed station A and which is made in a stationary cylindrical coaxial peripheral wall 305 which extends around the forming wheel 1. A tangential folder 6 is supported so that it can be moved parallel to its extension and alternately in both directions, in other words in the direction of advance of the forming wheel 1 and in the opposite direction, substantially along a path tangential to the forming wheel 1, in other words to the open side of the containing compartment 101 in the feed station A. The folder is fitted on the upper end of an arm 106 which is hinged at an intermediate point to a freely oscillating lever 206, while its opposite end is hinged to a link 306 which rotates integrally with a shaft 406. With reference to Fig. 2, the folder 6 is made in the form of a comb and has segments separated by interstices, which pass through complementary slots separated by ribs provided in a horizontal sliding surface 405 which forms the lower edge 205 of the aperture 5. With reference to Figure 3, the shaft 406 is driven in synchronization with the stepped drive of the forming wheel 1 by means of a transmission system which comprises a pair of gears 7, 8 which transfer the motion from a driven gear 9, which also drives the forming wheel 1, to a gear 110 keyed to a shaft 10 which rotates a cam 210. The cam 210 interacts with a pair of rollers 310 which are supported in an intermediate position by a sliding bar 410. The bar 410 is supported slidably longitudinally and radially with respect to the shaft 10 by its end 510 in the form of a slider which is mounted on a guide 610 carried on, and freely rotatable with respect to, the shaft 10. The opposite end of the bar 410 is hinged to a lever 11 which is fixed on and rotates integrally with the shaft 406 for driving the tangential folder 6. Figures 10 to 13 show the stages of folding of the flaps 102, 202 of the wrapping sheet 2 for the formation of a tubular wrapping open at its ends, the axis of which is parallel to the axes of the cigarettes S and to the axis of the forming wheel. The lengths of the two flaps 102, 202 are such that, when folded against the side of the group of cigarettes coinciding with the open side of the containing compartment 101, the flaps overlap each other by a certain amount. In the starting condition shown in Fig. 10, the flaps 102, 202 extend along two horizontal radial walls 405, 505 which are made to be aligned flush with the folding corners 105, 205 of the aperture 5 and which form containing walls for the said flaps 102, 202. During the stage in which the containing compartment 101 remains in the feed station A, the tangential folder 6, which is in the withdrawn position with respect to the containing surface 405 and backward with reference to the direction of advance of the forming wheel 1 (Fig. 10), begins the folding movement with which it moves in the direction of advance of the forming wheel 1 and substantially tangentially to the said wheel, in other words parallel to the corresponding side of the group of cigarettes S (Fig. 11). The flap 202 is therefore folded against the corresponding side of the group of cigarettes S. The forming wheel 1 executes the advance step with a predetermined delay with respect to the advance movement of the tangential folder 6. This delay and the two speeds of advance of the forming wheel 1 and of the folding blade 6 are such that the folder 6 terminates its movement relative to the flap 202 of the wrapping sheet 2 in such a position that the front edge of the folder 6 is withdrawn by a certain distance with respect to the free front edge of the flap 202, forming a free front strip 302. The horizontal surface containing the front flap 102 of the wrapping sheet 2 reaches a position in which its corner 605 for folding the said flap 102 is partially superimposed on the previously folded rear flap 202, with a stationary cylindrical surface which is coaxial with the forming wheel 1 of a peripheral wall 305 and covers the radially external open side of the compartments 101 over a predetermined arc of the path of advance, in particular over the angular distance between the feed station A and the subsequent folding station P. The corner 605 for folding the front flap 102 is disposed in a position aligned with and substantially directly adjacent to the edge of the open side of the containing compartments 101 in the feed station A. As shown in Fig. 12, the reaching of a fixed relative position of the tangential folder 6 with respect to the rear flap 202 causes the folder 6 to approach the corner 605 for folding the front flap 102. The extension of the front superimposition strip 302 in the direction of advance of the forming wheel 1 and the folding movement of the folder 6 in the direction of advance of the forming wheel 1 are such that the tangential folder 6 reverses its movement at a predetermined minimum distance from the corner 605 for folding the front flap 102. When the said minimum distance is reached, the front superimposition strip 302 of the rear flap 202 has penetrated under the folding corner 605, which has superimposed on this flap, having folded it, an initial partial portion of the front flap 102. In these conditions, the folded rear flap 202 is kept in position by the front flap 102 which is partially superimposed on it and the folder 6 can completely depart from the position of the folding of the associated rear flap 202, returning to the withdrawn starting position for a new folding movement. In the meantime, the advance of the forming wheel 1 causes the completion of the folding of the front flap 102 on to the corresponding side of the group of cigarettes. During the step of advance and up to the subsequent folding station P the flap 10, which is in a position of superimposition on all the remaining flaps, is kept in the said folded position by the cylindrical surface of the wall 305. Since the cigarettes, particularly those with filters, may have diameters which differ slightly between the filter and the cigarette, and the said two parts have different degrees of deformability, and in particular of compressibility, it is possible that, during the initial folding of the wrapping sheet 2 into a C shape in the passage across the aperture 5, the section of the group of cigarettes S in a plane parallel to the aperture 5 may assume a trapezoidal shape which then leads to the formation of a frustoconical tubular wrapping with different projections of the flaps 102, 202 at the two ends and a slightly helicoidal shape of the wrapping sheet 2 folded into a C shape, or the formation of pleats, etc. To avoid such problems, the invention provides compensating means which in the illustrated embodiment consist of means of fine adjustment of the distance between the two opposite folding edges 105, 205, at least at one of the two ends. With reference to Fig. 2, the aperture 5 is formed by a fork-shaped end of the cylindrical wall 305 which extends to the feed station A and which forms the lateral walls and the folding corner 105 which is at the front with reference to the direction of advance of the forming wheel 1. The opposite folding corner 205 is formed by the front edge of a plate 405 which is fixed to the ends of the lateral branches of the fork. The two lateral branches of the fork are of different lengths, while the distance between the two folding corners 105, 205 at the two ends is adjusted by the interposition of a spacing washer 705 with a suitably adjusted thickness between the said plate and at least one of the branches of the fork. The spacing washer 705 may be replaced with washers of different thicknesses which may be fitted singly or in combination, or may be suitably reduced in thickness as required at the time of the adjustment of the device. In the subsequent folding station P folding means are provided to close the open ends of the tubular wrapping formed in the feed station A and completed in the initial section of the step of advance of the containing compartment 101. The tubular wrapping formed by the sheet 2 has tubular end portions projecting beyond the ends of the cigarettes aligned with each other at their ends and forming opposite pairs of wings orientated in the radial direction 402, 502 and in the tangential direction 602, 702 with respect to the forming wheel 1, these wings being joined together at the axial contact corners. With reference to Figs. 1, 4, 9, a pair of folding blocks 15 is provided in the folding station P on each side of the forming wheel 1 to fold the radially inner tangential wing 602 and the radially outer tangential wing 702. The folding blocks 15 are disposed outside the corresponding wing 602, 702 and have folding surfaces 115 each of which terminates in a free edge substantially coinciding with or directly adjacent to the folding line L1 of the corresponding wing 602, 702 which coincides with the edge of the corresponding side of the group of cigarettes. The said free edge advantageously consists of a sharp corner 215 of the folding block 15, while the surface 115 in the rest position is disposed so that it diverges in the radial direction of the forming wheel 1 from the wing 602, 702. By this means, the group of cigarettes wrapped in the tubular wrapping may be introduced between the four folding blocks 15 in the rest position, without the possibility of these blocks interfering with the projecting ends of the tubular wrapping, which might cause unintended and undesirable folding. The blocks 15 can oscillate about an axis 0 which coincides with the corner 215. For this purpose, as shown in Figs. 1 and 6 to 9, each folding block 15 is supported by a bar 16 which is parallel to the axis of oscillation 0 of the folding blocks 15. One end of the bar 16 is fixed to the end of a radial arm 17 which rotates integrally with a shaft 18. The folding block 15 is fixed to, and projects from, the opposite end of the bar 16, in such a way that the line joining the axis of the bar 16 and the corner 215 is axially aligned with the radial arm 17, while the corner 215 is made to coincide with the extension of the axis 0 of the shaft 18 (Fig. 8). The shafts 18 are supported so that they can rotate freely in a wall 119 of a casing 19, and their inner ends rotate integrally with a crank 118 which carries an eccentric roller 218 which is rotatable about an axis parallel to the axis 0 of the shaft 18, this roller engaging slidably in a transverse guide in the form of a link 20 which is movable in an alternating way in a direction perpendicular to its longitudinal extension. The transverse guides 20 are fitted so that they can be removed and adjusted with respect to their position by means of a securing device or clamps 120 on respectively two arms 121, which are perpendicular to the guides and parallel to each other and which form part of an articulated quadrilateral indicated overall by the number 21. The ends of the arms 121 are interconnected by oscillating levers 221, 321 which are parallel to each other and which are hinged so that they can oscillate freely about perpendicular central axes 521, 621 which are aligned with each other in a direction parallel to the arms 121, 221. The articulated parallelogram 21 is driven with a reciprocating motion by means of a bar 22 which is hinged between a median radial extension 721 of the oscillating lever 321 and a radial projection 12" of a shaft 223 of what is known as an intermittent/oscillating drive device 23, for example of the type with a cylindrical and/or spheroidal cam 323 (such as the type marketed by Colombo Filippetti of Casirate d'Adda, BG). This construction makes it possible to adapt the relative disposition of the folding blocks 15 to the various cigarette and pack formats in a relatively rapid and simple way. In this case, it is sufficient to dismount the plate 119 with the shafts 18 and the bars 16. These may easily be mounted on another plate, in which the journals for the shafts 18 are provided in different relative positions. The connection of the cranks 118 in the corresponding guides 20 and their adjustment is extremely rapid and simple. A pair of opposing folding blades 25, 26 is provided on each side of the forming wheel 1 to fold the radial wings 402, 502 of the ends of the tubular wrapping projecting beyond the ends of the cigarettes S. The folding blades extend parallel and tangentially to the plane containing the ends of the cigarettes and can oscillate parallel to each other in the said tangential plane, alternately in the direction of advance of the forming wheel 1 and in the opposite direction on a path forming a secant to the wheel 1. Each folding blade 25, 26 has a transverse extension 125, 126 on the side facing the corresponding radial wing 402, 502. The trajectory of oscillation of the said folding blades 25, 26 is such that, during the stage in which the containing compartment 101 remains in the folding station P, the blades can assume a stand-by position (Fig. 15) in which they are swung into a position in which the extensions 125, 126 are aligned with the external surface of the corresponding side of the tubular wrapping, and in which they are in contact with the associated wings 402, 502, thus forming containing surfaces for the said wings 402, 502, as a substantial axial extension of the corresponding radial walls of the containing compartments 101. Each blade 25, 26 is carried on and projects from an arm 225, 226. The ends of the arms 225, 226 are fixed to and rotate integrally with associated driving shafts 27, 28. Each driving shaft 27, 28 carries the two corresponding folding blades 25, 26 on the two opposite sides of the forming wheel 1 (Fig. 4). With reference to Fig. 5, the shafts 27, 28 are made to rotate in both directions and through angular distances which are variable according to the movement of the folding blades 25, 26 by means of a corresponding intermittent/oscillating drive device with parallel axes indicated overall by the numbers 30, 31, the cams 130, 131 of the two oscillators 30, 31 being mounted in axial alignment with each other on the same shaft 32, while each driving shaft 27, 28 of the folding blades 25, 26 rotates integrally with the roller support group 230, 231. With reference to Fig. 1, to permit the presence of the radially outer folding blocks 15, the peripheral cylindrical wall 305 which surrounds the forming wheel 1 has an aperture, or rather an interruption 805 at the folding station P. Consequently, in order to keep the flaps 102, 202 on the radially outer side of the tubular wrapping in the folded position without interfering with the blocks 15, a retaining foot 33 is provided and is supported in such a way that it can be alternately brought closer to and distanced from the said side of the group of cigarettes wrapped in the tubular wrapping. The retaining foot 33 is slightly shorter than the axial extension of the corresponding side of the group of cigarettes S. The retaining foot 33 is carried at the end of a radial arm 134 of a system of articulated levers 34. The arm 34 is hinged, at an intermediate point and at its end opposite the foot 33, to a driven oscillating lever 234 and to an idle oscillating lever 334 respectively, the two levers being of identical length and having their axes of oscillation spaced apart by substantially the same distance as the axes of hinging to the radial arm 134. The lever 34 rotates integrally with a shaft 35. The foot 33 which has a contact surface orientated substantially parallel to the corresponding side of the group of cigarettes is therefore movable substantially alternately in the radial direction. The particular construction of the system of articulated levers makes it possible, in particular, to use the small components of motion in the direction transverse to the radial direction, in other words, in this case, parallel to the corresponding side of the group of cigarettes, in the sense that the said movement takes place at the end of the movement of contact with the tubular wrapping and in the direction of folding of the upper flap 102. The operation of the folding blocks 15, the folding blades 25, 26 and the retaining foot 33 in synchronization with the steps of advance of the forming wheel 1 and with each other is obtained by taking, in some suitable way, the motive power from a common motor or from a common power take-off. With reference to Figs. 1, 3, 5, 6, the driving shaft 35 of the retaining foot 33 is connected mechanically to the driven gear 9 from which the motion is taken for the forming wheel 1 and for the tangential folder 6 in a way similar to the latter. From the system for transmitting the motion to the tangential folder 6, the motion is transferred by means of a further gear 36 to a gear 137 keyed to a shaft 37. The rotary motion of the shaft 37 is converted into an alternating rotary motion of the shaft 35 by means of a transmission similar to that described with reference to the tangential folder 6. The rotary motion is transmitted to the parallel-axis oscillators 30, 31 driving the folding blades 25, 26, via removable rotating means 38 which couple the common input shaft 32 of the said oscillators 30, 31 to the driving shaft 10 of the tangential folder 6, while the rotary drive motion of the oscillator 23 is transmitted to the input shaft 423 of this oscillator by means 39 which couple the input shaft to the driving shaft 37 of the retaining foot 33 so that it rotates with it. Figures 14 to 24 show some stages of the folding of the radial and tangential wings 402, 502, 602, 702 which form the end portions of the tubular wrapping projecting beyond the ends of the group of cigarettes. In the folding station P, the containing compartment 101 coincides with the slot 805 in the peripheral cylindrical wall 305 and the retaining foot 33 is brought next to the folded and overlapping axial flaps 102, 202 of the wrapping sheet 2 to retain them in position. The front folding blades 25 are in the rest position, in which they are aligned with the extensions 125 and the folding corner with respect to the corresponding front radial wall of the compartment 101, so that the front radial wings 402 are made to bear on the extensions 125 of the blades 25. The blocks 15 are in the rest position (Fig. 9), with the edge 215 of the folding surface 115 disposed on the folding line L1 of the said tangential wings 602, 702, while the folding surface 115 diverges from the said wings 602, 702. This state is illustrated in Figs. 14 and 20. The rear folding blades 26 are then swung in the direction of advance of the forming wheel from a rest position in which they are remote from the wheel to a stand-by position in which they are aligned, similarly to the facing front folding blades 25, with the corresponding radial side of the containing compartment 101. In this way, the two radial wings 402, 502 projecting beyond the ends of the group of cigarettes are interposed between two associated containing walls, which prevent their bulging and/or deformation at the time of folding of the tangential wings 602, 702 which are joined as one piece with the first wings 402, 502 (see Figs. 15 and 22). Subsequently (Figs. 16, 21 and 22), the blocks 15 are swung into the position in which they fold the associated tangential wings 602, 702 against the corresponding ends of the group of cigarettes S. In this state, since the tangential wings 602, 702 are joined along the axial corners to the radial wings 402, 502, a substantially triangular part 802 of the end of the radial wings 402, 502 is refolded, simultaneously with the folding of the tangential wings 602, 702, on to the inner side of the latter wings, while at the corner areas of the ends of the group of cigarettes, the wrapping material has to change from a substantially convex state to a substantially concave state. To prevent the wrapping sheet from tearing in the course of this change, during the folding of the tangential sides 602, 702, the corresponding corner area 315 of the folding block 15 is chamfered and/or rounded. This makes it possible to avoid tension on the wrapping sheet 2 in the said corner area and consequently in the change from the concave state to the convex state of the wrapping sheet which in some sense undergoes a movement, in particular a virtual rotation, around the corner 315. In this condition of folding, the radial sides 402' and 502' have a configuration in the form of an isosceles trapezium, whose longest base coincides with the folding line L2 of these sides; in other words, it is tangential to or coincident with the radial edge of the end of the group of cigarettes S. Subsequently (see Figs. 17 and 23), the folding blocks 15 are swung back into the rest position, while the front folding blade 25 is activated which, with an angular movement tangential to the end of the group of cigarettes and in a direction opposite the direction of advance of the wheel, causes the front radial flap 402' to be folded on to the end of the group of cigarettes and superimposed on the previously folded tangential wings 602 and 702. The whole process takes place at a speed which is greater than that of the elastic return of the tangential wings to their unfolded or partially folded state, and which in any case is sufficient to prevent them from assuming a position which would adversely affect the correct folding of the sheet on to the ends of the group of cigarettes. At least the perpendicular extension 125 of the front folding blade 25 is of trapezoidal form, substantially corresponding to the trapezoidal form of the radial flaps 402', 502'. This enables the wait times of the operation of the folding blade 5 to be reduced, since the blade can start somewhat in advance, when the folding blocks 15 have executed only a part of the return movement and are in a position of intermediate elevation in which the angle between the folding surface 115 and the end of the group of cigarettes is slightly greater than the angle between the inclined sides and the base of the trapezoidal extension 125 of the folding blade 25. This blade may therefore be inserted under the folding blocks 15 while they are still at an intermediate point of the return movement. The rear folding blade 26 is operated before the start of the return movement of the front folding blade 25, and is swung in the direction of advance of the forming wheel 1 towards the front folding blade 25 until it reaches a certain distance from it. When the said minimum approach distance has been reached, the front folding blade 25 starts the return movement with a speed substantially equal to that of the rear folding blade 26. The folding movement of the rear folding blade 26 and the return movement of the front blade 25, as well as the path of the facing folding edges of the said folding blades 25, 26 and the minimum distance between them, are set in such a way that, in the end areas of the corresponding folding and return movements, the rear folding blade 26 is superimposed, directly or with the interposition of the rear radial flap 502 in the folded state, at least partially on the front radial flap 402, while the front blade 25 is still superimposed on the front end of the group of cigarettes (Fig. 18). In these conditions, the front radial flap 402 is kept in position both by the associated folding blade 25 and by the opposite folding blade 26. When this condition is reached, the forming wheel executes the step of advance, while the two folding blades 25, 26 end their simultaneous movement in the direction of advance of the forming wheel, with a certain delay with respect to the execution of the step of advance and at a speed lower than that of the step of advance of the compartments 101 (Fig. 19). The group of cigarettes is therefore moved with respect to the folding blades 25, 26 in the direction of advance of the wheel 1. The whole is adjusted and designed in such a way that, as shown in Fig. 19, the end of the rear and upper radial wing 502' which is free and faces the direction of advance of the forming wheel 1, is folded back and inserted under the folding edge of the front folding blade 25, while the rear blade 26 is still partially superimposed on an area on the opposite side of the said rear upper wing 502'. With reference to Fig. 24, the folding edge of the folding blade 25 has a chamfered or rounded guide portion 225 for this purpose. In the subsequent arc of the path of the second step of advance, the forming wheel 1 is associated with an extension of the peripheral coaxial cylindrical wall 305' to keep the axial flaps 102, 202 folded, and with a sliding surface 140 of a lateral wall 40 on each side of the forming wheel 1, to keep the wings 402, 502, 602, 702 folded on the ends of the group of cigarettes, the upper rear wings 502' of the ends of the packaged group of cigarettes sliding against the direction of the fold along the said surfaces (see Fig. 24). To permit the passage from the area of the folding blade 25 to the stationary surface 140 without letting the wings 502' catch on the facing leading edge of the sliding surface 140, the front folding blades 25 and the leading portions of the lateral walls 40 forming the surfaces 140 facing these blades have complementary recesses or thinner areas for reciprocal engagement 425, 240 on the sides facing each other. The whole being such that, at the end of the movement in the direction of advance of the forming wheel 1, the folding blades 25 are engaged with the walls 40 whose inner surfaces are substantially flush with the inner surfaces of the portions 525 of the blades 25 on the side of the folding edge. The ends of the surfaces 140 directly adjacent to the inner surfaces 525 of the folding blades 25 may advantageously be made in the form of inclined guide surfaces 340 so that the ends of the said surfaces are lower than the surfaces 525 of the folding blades 25 and thus further reduce the risk of catching the free front edge of the upper rear wing 502 in the opposite direction to the fold. In the embodiment illustrated, the walls 40, in other words the surfaces 140 and the wall 305', extend as far as the discharge station E on the side diametrically opposite the feed station A. However, Figure 1 shows that the wrapping is perfectly formed when it leaves the second folding station P, and therefore the discharge station may be disposed at the end of the second step of advance of the forming wheel 1. The folding procedure according to the preceding description, consisting in the operation in rapid succession of the folding means 6, 605, 15, 25, 26 at a speed easily higher than the speed of recovery, in other words of the elastic return of the folding flaps or wings 102, 202, 402, 502, 602, 702 in the folded position or in a position of intermediate folding, is not applicable to all wrapping materials. In particular, when sheets of polypropylene or of plastic material with a similar elastic behaviour or resistance to folding are used as wrapping materials, the operating speed required, particularly for the operation of the folding blocks 15 and of the front folding blade 25, may become excessively high. In order to avoid such problems, the invention provides a variant shown in Figs. 25 to 28. In this variant, the edge 215 of the folding blocks 15 about which the blocks 15 oscillate does not have a length substantially identical to the side and to the tangential wing 602, 702, as in the preceding example shown in Figs. 14 to 24, but, conversely, the edge 215' and consequently the blocks 15' are made shorter than the corresponding tangential wings 602, 702 on the side facing the front folding blade 25 and leave a strip 902 free on which an initial part of the radial wing 402 may be superimposed before the start of the return movement of the blocks 15. This is done by operating with a certain predetermined degree of advance of the front folding blade 25 for the execution of the folding movement with respect to the start of the return movement of the folding blocks 15. The dimensions of the peripheral strip 902, and the advance, as well as the speed of operation of the blocks 15' and of the front folding blade 25 are such that, when the strip has been overlapped by an amount sufficient to keep the tangential wings 602, 702 temporarily in the folded position, and at a predetermined minimum distance from the blocks 15 (Fig. 26), the blocks start their return movement to the rest position at a speed such that interference with the folding blade 25 is avoided.

Claims: Process for packaging products, particularly cylindrical products such as cigarettes, or the like, in a wrapping sheet, in which the following stages are provided: forming a group of cigarettes (S) with a predetermined number and order corresponding to those in the packed state; combining the group of cigarettes (S) with a wrapping sheet (2) in a predetermined relative position and inserting them into a containing compartment (101) with simultaneous folding of the wrapping sheet (2) into a "C" shape around the sides of the group of cigarettes (S) associated with the closed sides of the containing compartment (101); forming a tubular wrapping by folding and retaining in position the flaps (102, 202) of the wrapping sheet (2) on that side of the group of cigarettes at the open entrance side of the containing compartment (101); subsequently closing the open ends of the tubular wrapping by folding wings (402, 502, 602, 702) formed by the terminal portions at the ends of the tubular wrapping projecting beyond the corresponding sides of the group of cigarettes, in which the complete formation of the pack, in other words the complete folding of the wrapping sheet (2) around the ordered group of cigarettes (S), is executed in two stations (A, P) only, in other words in the station (A) where the group of cigarettes (S) and the wrapping sheet (2) are fed into the containing compartment (101) and in only one subsequent folding station (P) formed by one of the stations following the feed station, the pack being completely formed at the time of the step of advance for departure from the said folding station (P), the forming of the open tubular wrapping being executed substantially in the feed station (A) and completed during the step of advance, in other words in the initial portion of the step of advance, while the closing on the ends of the tubular wrapping is completed simultaneously for both opposite ends of the tubular wrapping in the folding station (P) and in the next step of advance, the completely formed wrapping is simply kept closed until the discharge station (E) is reached, characterized in that provision is made to leave free at least one peripheral strip (302, 902) for superimposition of an upper flap or wing on the lower flaps or wings (202, 402, 602, 702), this peripheral superimposition strip (302, 902) being provided on a directly adjacent side next to or facing the subsequent upper flap or wing (102, 402, 502), in other words a part of the flap which is folded into position first, the lower wing or flap (202, 402, 602, 702) being kept in the folded position only until the upper folding wing or flap (102, 402, 502) is at least partially superimposed on to the free superimposition strip (302, 902). Device for the application of the process according to claim 1, which comprises: means for forming an ordered group of cigarettes; means (4, 203) for feeding the said group together with a wrapping sheet (2) into a containing compartment (101) open at least at one entry side and at two sides transverse with respect to it; means (1, 201) for conveying the said containing compartment (101); movable and/or stationary folding means (5, 105, 205, 6, 605, 15, 115, 25, 26) which are distributed along the path of the compartment (101) for containing the group of cigarettes to be packed and the associated wrapping sheet (2), these means (5, 105, 205, 6, 605, 15, 115, 25, 26) being designed to fold the wrapping sheet (2) around the group of cigarettes to form a first tubular wrapping and subsequently to close the open ends of the said tubular wrapping; the movable and/or stationary folding means (5, 105, 205, 6, 605, 15, 115, 25, 26) being provided only in the feed station (A) and in only one of the subsequent stations, which is a folding station (P) for completing the packaging wrapper, and which is preferably the station immediately following the feed station (A), characterized in that the folding means (5, 105, 205, 6, 605, 15, 115, 25, 26) are shaped in such a way with respect to the flaps or wings (102, 202, 402, 502, 602, 702) and/or are operated in such a way that they stop at a certain distance from a free edge of the said flaps or wings, (202, 402, 502, 602, 702), leaving free a partial or complete strip (302, 902) for the superimposition of the subsequent flap or wing (102, 402, 502) and of the corresponding folder (605, 25, 26), on that side which is reached first by the folder (605, 25, 26) of the said subsequent wing or flap (102, 402, 502), the folding means (5, 105, 205, 6, 605, 15, 115, 25, 26) and the operating and synchronizing means being made in such a way that the folding means (6, 15, 25) of the lower wings or flaps (202, 602, 702, 402) and those (605, 25, 26) of the wings and flaps directly above (102, 402, 502) do not interfere with each other, while means are provided which advance the start of the folding movement of the folding means (605, 25, 26) of the upper wing or flap (102, 402, 502) with respect to the return movement of the folder (6, 15, 25) of the flap or wing immediately below (202, 602, 702, 402), this advance corresponding to the movement required for the superimposition of the said upper flap or wing (102, 402, 502) on the free peripheral superimposition strip (302, 902) provided on the lower flap or wing (202, 602, 702, 402). Device according to Claim 2, characterized in that the folding means (15, 25, 26) are made in such a way that they can be brought into a stand-by position directly adjacent to the wings or flaps (402, 502, 602, 702) of the wrapping sheet (2) which have not yet been folded, or are brought into this position during the idle or waiting time of these or of other folders, and with the folding edge (225, 215) substantially aligned and/or coinciding with the predetermined folding line (L1, L2). Device according to one or more of the preceding claims 2 and 3, characterized in that the wrapping sheet (2) is wrapped in a tubular form around the group of cigarettes (S), along an axis perpendicular to the direction of transport, while the open side of the containing compartment (101) is orientated parallel to the direction of transport or at a tangent and/or secant to the said direction of transport, at least one stationary folder (605) and at least one tangential movable folder (6) being provided in the station (A) for feeding the group of cigarettes into the containing compartment (101), and being disposed opposite each other with respect to the advance of the containing compartment (101), the tangential movable folder (6) being capable of being driven alternately forwards and backwards, in the direction of advance of the containing compartment (101) or in a direction tangential to the path of advance and transverse with respect to the flap (102, 202) of the wrapping (2) to be folded, with the provision of means of synchronized activation of the reciprocating motion of the tangential folder (6) with the advance of the containing compartment (101) and means of limiting the advance and return movements of the movable folder (6), these means being made in such a way that the movement of advance takes place in the direction of advance of the containing compartment (101), and is advanced to such an extent with respect to the step of advance of the said compartment (101) that the folder (6) assumes a stable relative position with respect to the free edge of the associated folded flap (202), forming a front peripheral strip (302) which is transverse with respect to the step of advance of the containing compartment (101), this strip (302) being designed to be partially inserted for a certain distance under the stationary folder (605) and under the part of the flap (102) folded by it, before the said movable folder (6) starts its return movement in the direction opposite the direction of advance of the containing compartment (101). Device according to one or more of the preceding claims 2 to 4, characterized in that, in the folding station (P), movable means (15, 25, 26) for folding the projecting end portions of the tubular wrapping are provided for each open end of the tubular wrapping, the end portions comprising at least one pair of first wings (602, 702) opposite each other and orientated tangentially to the direction of advance or in the direction of advance of the containing compartment (101), and at least two further, second wings (402, 502) opposite each other, joined at their ends to the two tangential wings (602, 702) and orientated transversely, preferably perpendicularly, with respect to the said tangential wings (602, 702) and to the direction of advance of the containing compartment (101), the movable folders (15) of the first wings consisting of a surface (115) which can oscillate about an axis (0) coinciding with a free edge (215) of the said surface and with the folding line (L1), in other words with the edge of the corresponding side of the group of cigarettes, from a position in which it is substantially aligned with and externally superimposed on the said wings (602, 702) in the unfolded state to the folded position of the wings, in which the folding surface (115) which can oscillate is turned over against the corresponding side of the group of cigarettes, and the folders (25, 26) of the second wings (402, 502) consisting of two blades opposite each other and with a folding edge movable to a position coinciding with or adjacent to the folding line (L2) of the said second wings (602, 702), in other words with the corresponding edge of the side of the group of cigarettes, these folding blades (25, 26) being capable of being driven with a sliding motion parallel and tangential to the plane containing the corresponding side of the group of cigarettes, one blade being driven in a direction opposite that of the other, and the blades being driven alternately, so that each carries out a folding movement in which the folding blades are at least partially superimposed on the corresponding side of the group of cigarettes and a return movement to the rest and/or stand-by position. Device according to one or more of the preceding claims 2 to 5, characterized in that the folders (605, 15, 25) of the tangential wings (60, 70) and of the front, with reference to the advance of the containing compartment (101), transverse and axial wings (102, 402), assume a rest position with respect to the containing compartment (101) and to the wings (102, 402, 602, 702) corresponding to the stand-by position, in which the folders (605, 15, 25) are substantially directly adjacent to the corresponding wings and to the folding lines (L1, L2) in the initial position of the active folding movement. Device according to one or more of the preceding claims 2 to 6, characterized in that the folders (15) of the wings (602, 702) tangential or parallel to the direction of advance of the containing compartments (101) consist of surfaces (115) of blocks (15) which oscillate about axes (0) coinciding with a peripheral edge (215) of the surfaces (115) and with the folding line (L1) of the said wings (602, 702), the said blocks (15) being supported on and projecting from the side substantially opposite that of the oscillation edge (215), so that the surfaces (115) are brought alternately into a stand-by position adjacent to the wings (602, 702) in the unfolded state and into a folding position in which they are turned over against the facing side of the group of cigarettes. Device according to Claim 7, characterized in that, in the stand-by position, the folding surfaces (115) are orientated so that they diverge outwardly and towards the end opposite the folding line (L1) with respect to the position of the associated wings (602, 702) in the unfolded state. Device according to one or more of the preceding claims 2 to 8, characterized in that, in the folding station P, the folding means (15 and 25) of the tangential wings (60, 702) and of the front transverse wings (402) on both ends of the group of cigarettes are disposed in the stand-by position, and the group of cigarettes wrapped in the tubular wrapping and contained in the compartment (1) is inserted with the lines corresponding to the folding lines (L1, L2) in a predetermined position of the configuration of the folders (15, 25) with the step of advance from the feed station to the folding station. Device according to one or more of the preceding claims 2 to 9, characterized in that the edge (215) of the oscillating folding surface (115) which is substantially coincident with or directly adjacent to the folding line (L1) of the corresponding tangential wings (602, 702) has a length substantially equal to that of the said line (L1), while the corner areas of the folding surface are chamfered or rounded (315) in the end area of the folding line (L1). Device according to Claim 10, characterized in that the oscillating folding surface (115) of the tangential wings (602, 702) and the free edge (215) coinciding with the folding lines (L1) and with the axis of oscillation (0) are formed by the surface facing the said wings and by the corresponding edge of a block (15) with a substantially trapezoidal transverse section, while the corner areas of the block (15) at the ends of the edge (15) are flattened, chamfered or rounded (315). Device according to one or more of the preceding claims 2 to 11, characterized in that blocks (15) are supported radially with each projecting from a bar (16) which is parallel to the axis (0) of a driving shaft (18) and which is supported rotatably about the said axis (0) by means of a radial arm (17) axially aligned with the line running between the edge (15) of the block (15) coinciding with the folding line (L1) of the tangential wing (602, 702) and the axis of the bar (16), while the driving shaft (18) is made to rotate in an alternating way and through a predetermined angle by means of a cranked end (118, 218) engaged with driving means (20, 121) providing an alternating traversing motion in the radial direction of the driving shaft (18). Device according to one or more of the preceding claims 2 to 12, characterized in that the driving shafts (18) of the folding blocks (15) of the corresponding tangential wings (602, 702) are mounted in a removable plate (119) with their axes (0) coinciding with the extensions of the folding lines (L1) of the associated tangential wings (602, 702), while so as to adapt to the different dimensions of the cigarettes and of the groups of cigarettes, a plurality of plates (119) is provided, each having a corresponding relative disposition of the supports for the rotation of the shafts (18), the means of transmission (118, 218, 20) and conversion of the alternating traversing motion into an alternating rotary motion of the shafts (18) and into an alternating oscillatory motion of the folding blocks (15) being adjustable to match the new folding movements, the end of travel positions and the synchronization of the folding blocks (15) to each other and to the other operating units. Device according to one or more of the preceding claims 2 to 13, characterized in that, at least on the side facing the front folding blade (25), the folding blocks (15) are made slightly shorter than the associated folding line (L1), by an amount such that a strip (902) is left free for the partial superimposition of the subsequent facing transverse wing (402') by the advance of the folding movement of the corresponding folding blade (25) with respect to the return movement of the folding blocks (15) to the rest position, without any collision between the folding blade (25) and the folding blocks (15). Device according to one or more of the preceding claims 2 to 14, characterized in that, before the operation of the folding blocks (15) for the tangential wings (602, 702) the front and rear folding blades (5, 6) are brought into the stand-by position, with the folding edge directly adjacent to and/or substantially coinciding with the folding lines (L2) of the transverse wings (402', 502'), the said folding blades being provided with transverse extensions (125, 126) which lie side by side with each other from the outside parallel to the corresponding transverse wings (402', 502'), forming a containing channel in the unfolded position of the said transverse wings at the time of folding of the tangential wings (602, 702) and of folding on to these of the outer triangular parts (702) of the transverse wings (402). Device according to one or more of the preceding claims 2 to 15, characterized in that the extension (125) of at least the folding blade (25) is of trapezoidal shape, substantially corresponding to the trapezoidal shape assumed by the transverse wings (402', 502') after the folding of the tangential wings (602, 702), while the said folding blade (25) and the folding blocks (15) are synchronized with each other in such a way that the folding blade (25) reaches the folding blocks (15) when these blocks are in an intermediate return position with the folding surface (115) which has a smaller inclination with respect to the perpendicular at the corresponding side of the group of cigarettes than that of the inclined sides of the extensions (125) of the folding blades (25). Device according to one or more of the preceding claims 2 to 16, characterized in that the containing compartments (101) are disposed in such a way that the group of cigarettes and the tubular wrapping are orientated with the ends parallel to the direction of transport, while the folding blades (25, 26) are made so that they can be moved tangentially to the ends of the group of cigarettes, the containing compartments (101) being open at the said ends, while the front folding blades (25) and the rear blades (26) are fitted in pairs on a common shaft (27, 28) for the execution of opposing folding and return movements with an alternating oscillatory motion, the whole being designed in such a way that, in the stand-by position, the folding blades (5, 26) are disposed with the folding edges completely parallel and/or coinciding with the folding lines (L2) of the associated transverse wings (402, 502), while during the folding movement the folding edge assumes an inclined position with respect to the direction of the folding line (L2) and to the folding edge of the facing folding blade (25, 26), in such a way that each of the opposing folding blades (25, 26) can be superimposed on the wing (502', 402') associated with the opposite folding blade (26, 25) before this blade has released the said associated wing (502', 402'), a minimum distance for non-collision and/or non-interference between the said folding blades (25, 26) being maintained by the execution of alternating oscillatory movements in the same direction and substantially at the same speed and/or in opposite directions. Device according to one or more of the preceding claims 2 to 17, characterized in that between the feed station (A) and the folding station (P) a wall is provided for retaining the flaps (102, 202) of the tubular wrapping superimposed on each other in the position in which they are folded on to the corresponding side of the group of cigarettes, this side coinciding with the open side of the containing compartment (101) and being orientated parallel or tangentially to the direction of transport, the side of the group of cigarettes sliding against the said stationary wall (305) in the direction of folding of the upper flap (102), and the said wall extending tangentially to the path of the open side of the containing compartment (101) and in the direction of transport. Device according to Claim 18, characterized in that the wall (305) for superimposition on the open sides tangential to the direction of transport of the containing compartments (101) has an aperture (805) in the folding station (P), while it extends (305') beyond this station to the discharge station (E), the folding station (P) being provided with removable means (33) for retaining the flaps (102, 202) on the open side of the containing compartment (101), it being possible to operate these means in synchronization with the steps of advance of the containing compartments (101). Device according to one or more of the preceding claims 2 to 19, characterized in that, on the transport path between the folding station (P) and the discharge station (E), for each end of the group of cigarettes, a wall (40) is provided with a surface (140) for retaining in position the wings (402, 502, 602, 702) of the wrapping folded on to the said ends of the group of cigarettes, the said wrapped ends of the group of cigarettes sliding along the said surface. Device according to Claim 20, characterized in that the upper wing at each end of the group of cigarettes is formed by the rear transverse wing (502') which, in the position in which it is folded on to the underlying wings (402, 602, 702), is orientated with its free front edge in the direction of advance, while the front folding blade (25) forms a movable extension (525) of the wall (40, 140), a portion of the surface (525) facing the group of cigarettes and lying along the folding edge aligned with the plane of the stationary sliding surface (140), and the facing ends of the front folding blade (25) and of the wall (40) being provided with complementary recesses or thinner areas (240, 425) for mutual engagement, for the positioning of the folding blade (25) in a position in which its inner surface is directly adjacent to the sliding surface (140, 525). Device according to Claim 21, characterized in that the folding edge of the folding blade (25) is made rounded or chamfered (225), while the leading portion directly adjacent to the inner surface (525) of the folding blade (25) is made in the form of a guide surface (340), in other words becomes thinner in the form of a wedge towards its end, which is recessed with a step from the adjacent inner surface (525) of the folding blade (25). Device according to Claim 19 or 20, characterized in that the means of operating the folding blades (25, 26) comprise means (30, 31) of synchronizing the motion of the folding blades (25, 26) with each other and with the folding blocks (15) and with the steps of advance of the forming wheel (1), the said synchronizing means being made in such a way that the front folding blade (25) executes the folding movement first and the folding blade (26) executes the folding movement with a certain advance with respect to the start of the return movement of the front folding blade (25), being brought to a certain minimum distance from the front folding blade (25), at least when both folding blades are near the end of travel position of the return movement in the case of the front folding blade (25) and of the folding movement in the case of the folding blade (26), while the forming wheel (1) executes the step of advance with a certain advance with respect to the moment at which the two folding blades (25, 26) reach the end of travel positions of the return and folding movements. Device according to one or more of the preceding claims 2 to 23, characterized in that the motion of the tangential folder (6), the folding blocks (15), the folding blades (25, 26) and the retaining foot (33) is taken by means of a mechanical transmission system (7, 8, 10, 36, 37, 110, 137, 210, 310, 410, 510, 610, 406, 35) from the same power take-off (9) as for the drive to the forming wheel (1). Device according to one or more of the preceding claims 2 to 24, characterized in that the conveyor (1) consists of a forming wheel provided with at least one, and preferably more, radial peripheral containing compartments (101) which are provided at equal angular intervals, with their tangential open sides disposed at the periphery of the forming wheel, the tubular wrapping being formed by wrapping the wrapping sheet about an axis parallel to the axis of the forming wheel, and the sides of the compartments (101) on the sides of the wheel being made open so that the end portions of the tubular wrapping forming the closing wings (402, 502, 602, 702) of the said ends of the tubular wrapping project from the compartments.

Inventors: SPADA VALTER, SPADA, VALTER
Applicants: SASIB TOBACCO SPA, SASIB TOBACCO S.P.A.
Application year: 1996
Main classification: B65B19
IPC codes: B65B19, B65B11