PACKING MACHINE, PARTICULARLY FOR CIGARETTES

Abstract: The invention relates to a packing machine, particularly for cigarettes, comprising: a drum (4) which is rotatable, preferably step by step, and which carries tubular molds, so-called arbors (7), around which the pack is formed; a cam (19′, 139) which is co-axial withthe arbor-carrying drum (4) and is provided with two annular guiding surfaces (45, 46; 143, 243); a flap-holding pressor (8) which is associated with one side of each arbor (7), said pressor being supported by an L-shaped arm (10) which is pivoted (12) on the arbor-carrying drum (4) and is provided with a roller (14) cooperating with one of the two annular guiding surfaces (46) of the cam (139); a sheet-retaining pressor (9) which is associated with the opposite side of each arbor (7), said pressor being supported by an L-shaped arm (11) which is pivoted (13) on the arbor-carrying drum (4) and is provided with a roller (15) cooperating with the other of the two annular guiding surfaces (45) of the cam (139). According to the invention, each annular guiding surface cooperating with the roller (14, 15) of the pressors L-shaped arms (10, 11) consists of a circular groove (45, 46) co-axial with the arbor-carrying drum (4), said groove comprising groove sectors (143, 243) which are reciprocatingly movable in a radial direction, so as to deviate the rollers (14, 15) from a circular path or to bring back the rollers (14, 15) on a circular path, thus causing the angular displacements of the associated flap-holding pressors (8) and sheet-retaining pressors (9).

Description: The invention relates to a packing machine, particularly for cigarettes, comprising: a drum which is rotatable, preferably step by step, and carries tubular molds, so-called arbors, around which a pack is formed; a cam which is co-axial with the arbor-carrying drum and is provided with two annular guiding surfaces; a flap-holding pressor which is associated with one side of each arbor, said pressor being supported by an L-shaped arm which is pivoted on the arbor-carrying drum and is provided with a roller cooperating with one of the two annular guiding surfaces of the cam; a sheet-retaining pressor which is associated with the opposite side of each arbor, said pressor being supported by an L-shaped arm which is pivoted on the arbor-carrying drum and is provided with a roller cooperating with the other one of the two annular guiding surfaces of the cam, whereby the flap-holding pressors and the sheet-retaining pressors perform a movement away from the arbor (so called opening movement) and a movement toward the associated arbor (so-called closing movement). In the known cigarette-packing machines of this kind, the arbors are moved together with the associated flap-holding pressors and sheet-retaining pressors, the one after the ao other to different stations, at which distinct operative steps of the packing procedure are carried out. The pressors are driven into their different positions that are required for the relative operative steps to be executed, either during the displacement from one station to the next or at the stations themselves. In a known packing machine of this kind, as described in the GB-A-849 594, the angular displacements of the flap-holding pressors and sheet-retaining pressors is induced by the profile of respective annular guiding surfaces of a cam, by the rollers of the L-shaped arms carrying the pressors,which rollers slide on said guiding surfaces, and by compression springs. These compression springs operate between the L-shaped arms of the couple comprising a flap-holding pressor and a sheet-retaining pressor of each arbor and produce the compression force of said pressors against the associated arbor. The control cam for the pressors is driven with a reciprocating continuous rotary motion, which is appropiately synchronized with the step by step rotation of the arbor-carrying drum. Disadvantageously, noise an vibrations are produced by this known packing machine, the intensity of which reaches intolerable levels particularly when the working rate increases. Further, the particular structure of the pressor-driving means does not allow to adjust the amplitude of the angular displacement of the pressors. The present invention aims to provide a packing machine ao of the type as described in the preamble, by which it may be possible to eliminate the springs, to deaden any noise and vibration and to adjust the amplitude of the angular displacements of the pressor and which should be of a simple and extremely inexpensive constructuion and should afford a reliable and quiet operation. The invention attains these objects by providing a packing machine of the type described above, wherein each annular guiding surface cooperating with the roller of the pressors L-shaped arms consists of a circular groove co-axial with the arbor-carrying drum, said groove comprising groove sectors which are reciprocatingly movable in a radial direction, so as to deviate the rollers from a circular path or to bring back the rollers on a circular path, thus causing the angular displacements of the associated flap-holding pressors and sheet-retaining pressors. Thanks to the radially movable groove sectors, the packing machine according to the present invention allows a simple adjustment of the ampliture of the pressors angular displacements. Further, since the guiding surfaces for the roller associated with the pressors of each arbor are in form of grooves, there is no need to apply springs for the production of a copression force. The intensity of noise and vibrations is notably decreased even at very high working rates to tollerable levels. The invention also relates to other characteristics which improve further said packing machine and form the subject of the subclaims. The particular characteristics of the invention and the advantages resulting therefrom will appear with more details from the description of a preferred embodiment, shown as non-limiting example in the accompanying drawings, wherein: Figure 1 is a cross sectional view of a packing machine according to the invention; Figure 2 shows a detail of the guide for the control of the sheet-retaining arms according to Figure 1, the drum being omitted; Figure 3 shows diagrammatically the cam for the control of the sliders, with an associated slider; Figure 4 is a diagrammatical front view of the guide tracks, together with the arbors and respective flap-holding and sheet-retaining pressors, the drum being omitted; Figure 5 shows the cam and the sliders associated therewith, in the relative position they assume in Figure 4. Figures 1 to 5 show an exemplary embodiment of the device according to the invention. It comprises a tubular shaft 1 actuated by a motor (not shown) and rotatably supported, through a bearing 2, in a portion 3 of the frame. A drum 4 is secured on an end portion of the tubular shaft 1 by means of a sleeve 5. The drum 4 has affixed thereto a plurality of equally-spaced spokes 6 carrying overhanging arbors 7. In the Figures 1 to 5, for simplicity sake, only a few arbors are shown, i.e. in a number which is strictly required to understand the invention. Thus, for example, in Figures 4 and 5 there are shown only the arbors 7 that are at the operating stations E, A, B, C and D where the controls according to the present invention are important. Each arbor 7 has associated therewith, at one side a flap-holding pressor 8, and at the opposite side a sheet-retaining pressor 9, each of which is mounted on an arm 10, 11 respectively. The arms 10 of the flap-holding pressors 8 and the arms 11 of the sheet-retaining pressors 9 are pivoted to the drum 4 through their extensions 110, 111 at 12 and 13, respectively, and each of them is provided, on the side facing the drum 4, with a small roller 14, 15. These rollers protrude beyond the rear side of the drum 4 through elongated openings 16. A control device (not shown) rotates the shaft 1 intermittently, whereby the drum 4 is rotated step by step, with alternated dwell periods and rotation steps having, preferably, an amplitude of 45°. Directly downstream of the arbor-carrying drum 4, there is secured on a portion of the machine's frame 3 a cashing 39. A cam 19′ is rotatably mounted on the tubolar shaft 1, through bearings 37 and 38, the cam 19′ being housed inside the cashing 39. The cam 19′ is put in continuous rotational motion by means of gearwheels 40 and 41. On the side facing the drum 4, the cam 19′ is provided with six concentric closed-track grooves 42E, 42E′, 42A, 42B, 42C, 42D (Figures 3 and 5), each of said grooves engageably receiving the roller 44 of a radial slider 43E, 43E′, 43A, 43B, 43C, 43D (Figures 3 and 4) associated with the respective working station E, A, B, C, D. As shown also in Figure 2, the front wall 139 of the casing 39, disposed between the cam 19′ and drum 4, comprises on its side facing the drum 4 two circular grooves 45 and 46 which are coaxial with the tubular shaft 1 and are interrupted by radial grooves 47 each of which slidably receives a slider 43E, 43E′, 43A, 43B, 43C, 43D (Figures 4 and 5). Two radial grooves 47 are arranged upstream and downstream of the station E, while a groove 47 is arranged downstream of the station A and downstream of the station C, and a groove is arranged upstream of the station B and upstream of the station D, respectively. The roller 44 of each slider 43 is arranged on the side facing the cam 19′ of said slider 43 and protrudes into the interior of the casing 39 through elongated slots 48 in the bottom wall of each radial groove 47. On the side opposite from the roller 44, each slider 43 comprises two groove-sectors 143, 243 which are arcuated correspondingly to the curvature of the circular grooves 45 and 46 so as to complete them. As appearing from Figures 1, 2 and 4, the circular groove 45 in the wall 139 of the casing engageably receives the rollers 15 of the arms 11 of the sheet-retaining pressors 9 and the groove 46 engageably receives the rollers 14 of the arms 10 of the flap-holding pressors 8. Thanks to the particular shape of the grooves 42E, 42E′, 42A, 42B, 42C, 42D wherein the rollers 44 of the associated sliders 43 are engaged, the cam 19′ can displace the sliders 43 to a position wherein the groove-sectors 143, 243 merge flush with the circular grooves 45 and 46 in the front wall 139 of the casing 39. Said position corresponds to the closing step of the flap-holding pressors 8 or sheet-retaining pressors 9. Further the cam 19′ can bring the sliders 43 to a position wherein the sliders 43 are displaced radially inwardly of the cam 19′ whereby the groove-sectors 143 and 243 of said sliders are offset radially inwards with respect to the associated circular grooves 45 and 46, so as to displace to an opened position the flap-holding pressors 8 and sheet-retaining pressors 9, whose rollers 14 and 15 are engaged in the groove-sectors 243 or 143 of the sliders 43. In the case of this embodiment, the cam 19′ is rotated continuously, one revolution of the cam corresponding to one step of rotation of the drum 4. With reference to the known packing machines wherein the cam rotates reciprocatingly, thus needing appropiate driving means, the continuous rotational motion of the cam 19′ represents a further advantage of the invention from the structural point of view. During the step of rotation of the drum 4, the rollers 14 and the rollers 15 of the flap-holding pressors 8 and sheet-retaining pressors 9 respectively slide in the tracks 46 and 45 of the front wall 139 of the stationary casing 39. On completion of said step of rotation of the drum 4, and as appearing from Fig. 4, the rollers 15 of the sheet-retaining pressors 9 are engaged in the groove-sectors 143 of the sliders 43E′, 43A and 43C associated with the stations E, A, C, while at the stations E, B and D the sliders 43E, 43B and 43D receive in their groove-sectors 243 the roller 14 of the respective flap-holding pressor 8. Thanks to the particular shape of the grooves 42E, 42E′, 42A, 42B, 42C and 42D of the cam 19′ and to their timing, during the rotation of the cam, with the drum 4 in the dwell period, the sliders 43E, 43E′, 43A, 43B, 43C and 43D are displaced radially towards the center of the cam 19′, thus causing the opening of the sheet-retaining pressors 9 at the stations E, A and C, and the opening of the flap-holding-pressors at the stations E, B and D, while the flap-holding pressors are kept in their closed position at the stations A and C and the sheet-retaining pressors 9 are kept in their closed position at the stations B and D. At the station E, as described previously in connection with the preceding embodiment, both the sheet-retaining pressor 9 and flap-holding pressor 8 will be opened. During the rotation of the cam 19′, the sliders are, then, moved again to the outer radial position wherein all the flap-holding and sheet-retaining pressors are closed, and the drum 4 may perform a new step of rotation to advance the arbors to the next station. Of course, the invention is not limited to the embodiments just described and shown, but broad changes and modifications, especially of constructional nature, may be made thereto. Thus, for example, a lower or higher number of stations may be provided, with no limitation to five stations, and the shapes and paths of travel of the grooves in the cams may be modified to comply with several requirements, all without departing from the basic principle set forth above and claimed hereinafter.

Claims: A packing machine, particularly for cigarettes, comprising: a drum (4) which is rotatable, preferably step by step, and which carries tubular molds, so-called arbors (7), around which the pack is formed; a cam (19′, 139) which is co-axial whith the arbor-carrying drum (4) and is provided with two annular guiding surfaces (45, 46; 143, 243); a flap-holding pressor (8) which is associated with one side of each arbor (7), said pressor being supported by an L-shaped arm (10) which is pivoted (12) on the arbor-carrying drum (4) and is provided with a roller (14) cooperating with one of the two annular guiding surfaces (46) of the cam (139); a sheet-retaining pressor (9) which is associated with the opposite side of each arbor (7), said pressor being supported by an L-shaped arm (11) which is pivoted (13) on the arbor-carrying drum (4) and is provided with a roller (15) cooperating with the other of the two annular guiding surfaces (45) of the cam (139), whereby the flap-holding pressors (8) and the sheet-retaining pressors (9) perform a movement away from the arbor (7) (so called opening movement) and a movement toward the associated arbor (7) (so-called closing movement), characterized in that each annular guiding surface cooperating with the roller (14, 15) of the pressors L-shaped arms (10, 11) consists of a circular groove (45, 46) co-axial with the arbor-carrying drum (4), said groove comprising groove sectors (143, 243) which are reciprocatingly movable in a radial direction, so as to deviate the rollers (14, 15) from a circular path or to bring back the rollers (14, 15) on a circular path, thus causing the angular displacements of the associated flap-holding pressors (8) and sheet-retaining pressors (9). A packing machine according to Claim 1, characterized in that the closed circular grooves (46, 45) in which the rollers (14, 15) of the flap-holding arms (10) and sheet-retaining arms (11) can slide, are formed in the surface facing the arbor-carrying drum (4) of a stationary wall (139) placed directly downstream of the arbor-carrying drum (4), said stationary wall (139) comprising radial grooves (47) each of which slidably receives a slider (43) which, on the side facing the drum (4), comprises two groove-sectors (143, 243) whose arcuate shape corresponds to that of the circular grooves (45, 46), and on the opposite side is provided with a roller (44), said slider being constructed so as to complete with its groove-sectors (143-243) the circular grooves (45, 46) interrupted at said radial grooves (47), while the radial displacement of said sliders (43) is controlled by a rotating cam (19′) placed directly downstream the stationary wall (139) and formed also with a closed-track shaped groove (42) for the roller (44) of each slider (43). A packing machine according to Claim 2, characterized in that the cam (19′) is set in a continuous rotary motion. A packing machine according to Claim 2, characterized in that the cam (19′) and the arbor-carrying drum (4) are synchronized, so that one complete revolution of the cam (19′) corresponds to one rotational step of the arbor-carrying drum (4). A packing machine according to any one or more of the preceding Claims, characterized in that the shaped close-track grooves (42) have a path shaped in such a manner that each slider (43) may assume two control positions of the respective flap-holding arms (10) and sheet-retaining arms (11), namely a position in which the groove sectors (143, 243) merge with the circular grooves (45, 46), and a position which said sectors are offset radially with respect to said circular grooves, for example, inwardly. A packing machine according to any one or more of the preceding Claims, characterized in that the stationary wall (139) is the front wall of a casing (39) secured to the machine frame (3) and the cam (19′) is housed inside the said casing (39). A packing machine according to any one or more of the preceding Claims and wherein each arbor (7) is displaced at a plurality of successive working stations (A, B, C, D, E), corresponding to distinct forming phases of the box, characterized in that each working station (A, B, C, D, E) in which one of the flap-holding pressors (8) or one of the sheet-retaining pressors (9) of one arbor (7) has to operate, is associated with at least one slider (43A, 43B, 43C, 43D, 43E or 43E′) being placed in such a manner that the roller (14, 15) of the flap-holding pressor (10) or sheet-retaining pressor (11) operating at said station (A, B, C, D, E) engages with the respective arcuate shaped groove sectors (143, 243) of the slider (43A? 43B, 43C, 43D, 43E or 43E′). A packing machine according to Claim 7, characterized in that each working station (E) in which both the flap-holding pressor (8) and the sheet-retaining pressor (9) of one arbor (7) placed at that station (E) have to operate, is associated with two sliders (43E, 43E′) being placed in such a manner that the roller (14) of the flap-holding pressor (8) and the roller (15) of the sheet-retainig pressor (9) of said arbor (7) engage respectively whith the arcuate shaped groove sector (243) belonging to one of the sliders (43E)and with the arcuate shaped groove sector (143) belonging to the other slider (43E′).

Inventors: MASOTTI,  CARLO, ROFFI, ROBERTO, Masotti, Carlo
Applicants: SASIB S.P.A.
Application year: 1989
Main classification: B65B19
IPC codes: B65B19