BACKGROUND OF THE INVENTION 0001 The present invention relates to a rigid container for tobacco products. 0002 The invention finds application to particular advantage in the manufacture of hinge-lid cigarette packets fashioned from relative flat precreased and diecut blanks of cardboard or the like, to which reference is made explicitly in the following specification albeit implying no limitation. 0003 The traditional type of rigid packet appears as a parallelepiped of rectangular section with sharp longitudinal corner edges; such a packet presents certain drawbacks deriving from a shape not readily adaptable to the human anatomy, and from the fact that the aforementioned longitudinal corner edges can occasion wear on the pockets of garments worn by the smoker. 0004 These problems have been addressed by the prior art, which offers a rigid packet with longitudinal corner edges presenting a rounded profile that has a radius of curvature matched to that of a single cigarette. In addition to overcoming the drawbacks mentioned above, this type of packet affords the advantage that it can be fashioned from a flat diecut blank of smaller surface area than that of traditional blanks, thus bringing a cost benefit. Nonetheless, it has been found that a packet made in this way still presents certain drawbacks. 0005 A first drawback is that the absence of sharp longitudinal corner edges results in a diminished structural rigidity tending to render the packet easily deformable, especially along the rounded corner edges. Any deformation of the rounded corner edge will impact directly on the single cigarette occupying this same corner of the packet, given that approximately one quarter of the cylindrical surface area presented by the cigarette is breasted with the internal surface presented by the radiused band of material coinciding with each one of the four longitudinal corner edges. 0006 A second drawback is that the rounded corner edges in question can be produced only by making extensive modifications to conventional packer machines. In particular, complex deforming steps are required in order to precrease the areas of the blank that will provide the bands constituting the rounded corner edges on the finished packet. 0007 Another drawback is that traditional cellophaners of the type used to envelop single packets with a sheet of transparent overwrapping material were designed originally to handle parallelepiped packets with sharp longitudinal corner edges. Such overwrapping machines have been found unsuitable for packets of the type referred to here. Most noticeably, surplus material tends to bunch around the top and bottom end faces at the ends of the rounded corner edges, forming unsightly creases and folds which in particular will project from the faces of the packet once the heat seal step has been effected. 0008 The object of the present invention is to fashion a rigid container for tobacco products that will be free of the drawbacks mentioned above.

SUMMARY OF THE INVENTION 0009 The stated object is realized according to the present invention in a rigid container for tobacco products appearing prismatic in shape, which comprises a top end face, a bottom end face and a plurality of side faces. At least two mutually adjacent side faces of the container each present a respective flat portion and at least one longitudinal lateral band of curved profile with the concave surface directed inwards, embodied in such a way that the lateral bands of the two adjacent faces are joined one to another along a sharp longitudinal corner edge.

BRIEF DESCRIPTION OF THE DRAWINGS 0010 The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which: 0011 FIG. 1 illustrates a packet representing a first embodiment of the container according to the present invention, viewed in perspective from the front and shown in a closed configuration; 0012 FIG. 2 shows the packet of FIG. 1 in the open configuration, viewed in perspective from the front; 0013 FIG. 3 shows the packet of FIG. 1 in the closed configuration, viewed in perspective from the rear; 0014 FIG. 4 shows a diecut blank used to manufacture the packet of FIG. 1; 0015 FIGS. 5 and 6 show the packet of FIG. 1 obtained from the blank of FIG. 4, viewed in plan from above and from beneath, respectively; 0016 FIG. 7 illustrates a variation on the packet of FIG. 1, viewed in plan from above; 0017

FIGS. 5

a, 6a and 7a are enlarged details of FIGS. 5, 6 and 7, respectively; 0018 FIGS. 8 and 9 illustrate a packet representing a second embodiment of the container according to the present invention, viewed in perspective; 0019 FIG. 10 shows a diecut blank used to manufacture the packet of FIG. 8; 0020 FIG. 11 shows the packet of FIG. 8 obtained from the blank of FIG. 10, viewed in plan.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 0021 FIGS. 1, 2 and 3 and FIGS. 8 and 9 of the drawings illustrate two packets of cigarettes as examples of the rigid container for tobacco products according to the present invention. The respective packets are denoted 1 in FIGS. 1, 2 and 3, and 2 in FIGS. 8 and 9. Both packets 1 and 2 are prismatic in appearance, comprising a container 3 with an open top end, denoted 4, surmounted by a lid 5 hinged to the container 3 and rotatable thus relative to the container 3 between an open position and a closed position in which the top end 4 is concealed, and serve to accommodate a respective group of cigarettes 6 (indicated in FIGS. 2 and 9). 0022 With the lid 5 occupying the closed position, in the example of FIGS. 1, 2 and 3, the packet 1 assumes the appearance of a substantially rectangular parallelepiped compassed by four side faces, namely a front face 7 and a rear face 8 parallel one with another, two flank faces 9 substantially parallel one with another and substantially perpendicular to the front and rear faces 7 and 8 and joined to these same faces 7 and 8 along respective sharp corner edges 10, also a top end face 11 and a bottom end face 12 parallel one with another and perpendicular to the side faces 7, 8 and 9. 0023 The four side faces 7, 8 and 9 are externally convex, and more exactly, each of the larger side faces 7 and 8 presents a flat central portion 13 of substantially rectangular outline; similarly, each of the flank faces 9 presents a flat central portion 14 of substantially rectangular outline. The flat central portions 13 of the larger faces are delimited at the top by a rectilinear central portion 15 presented by one longer side 16 of the top end face 11, and delimited at the bottom by a rectilinear central portion 17 presented by one longer side 18 of the bottom end face 12; the top and bottom rectilinear central portions 15 and 17 are identical one to another. 0024 Similarly, the flat central portions 14 of the flank faces are delimited at the top by a rectilinear central portion 19 presented by one shorter side 20 of the top end face 11, and delimited at the bottom by a rectilinear central portion 21 presented by one shorter side 22 of the bottom end face 12; the top and bottom rectilinear central portions 19 and 21 are identical one to another. 0025 Each larger face 7 and 8 further comprises two longitudinal lateral bands 23 located one on each side of the central portion 13; similarly, each flank face 9 further comprises two longitudinal lateral bands 24 located one on each side of the central portion 14. In particular, each lateral band 23 of the larger faces 7 and 8 is joined to a respective lateral band 24 of the flank faces 9 along a sharp corner edge 10. 0026 Moreover, each lateral band 23 of the larger faces 7 and 8 extends laterally from the respective central portion 13 with no break in continuity, that is to say with no discontinuity in the variation of its curvature; similarly, each lateral band 24 of the flank faces 9 extends laterally from the respective central portion 14 with no break in continuity, that is to say no discontinuity in the variation of its curvature. 0027 Each band 23 and 24 is rendered pliable by longitudinal crease lines 25, so as to assume a curved profile with the concave surface directed toward the inside of the packet 1. In particular, each band 23 of the larger faces 7 and 8 presents a top edge offered to a curved portion 26 presented by the longer side 16 of the top end face 11, and a bottom edge offered to a curved portion 27 presented by the longer side 18 of the bottom end face 12; the top and bottom curved portions 26 and 27 are identical one to another. 0028 Similarly, each band 24 of the flank faces 9 presents a top edge offered to a curved portion 28 presented by the shorter side 20 of the top end face 11, and a bottom edge offered to a curved portion 29 presented by the shorter side 22 of the bottom end face 12; the top and bottom curved portions 28 and 29 are identical one to another. 0029 In the light of the foregoing it will be evident that the distance between the central portions 13 of the larger faces 7 and 8, measured normal to these same faces, is greater than the corresponding distance between the corner edges 10, and similarly, the distance between the central portions 14 of the flank faces 9, measured normal to these same faces, is greater than the corresponding distance between the corner edges 10. 0030 The front, rear and flank faces 7, 8 and 9 each include an upper portion denoted by the suffix a, coinciding with a relative face of the lid 5, and a lower portion denoted by the suffix b coinciding with a relative face of the container 3, whilst the top end face 11 coincides with the top of the lid 5 and the bottom end face 12 with the bottom of the container 3. 0031 With the lid 5 occupying the closed position, the three upper portions 7a, 8a and 9a lie with the respective free edges offered to corresponding free edges of the lower portions 6b, 7b and 7b, whilst the edge presented by the rear face 8a of the lid 5 is joined permanently to the edge presented by the rear face 8b of the container 3, the two combining to create a hinge 30 about which the lid 5 is rotatable between the open and closed positions. 0032 As illustrated in FIG. 2, the rigid packet 1 comprises a stiffening frame 31 of U-profile projecting partially beyond the open top end 4, composed of a breast piece 32 rigidly associated with the inside of the front face 7, and, connected to the breast piece 29, two side pieces 33 each rigidly associated which the inside of a relative flank face 9. 0033 The breast piece 32 presents a flat central portion 34 destined to adhere in part to the respective inside surface of the flat central portion 13 presented by the front face 7 of the packet 1, and two respective precreased lateral bands 35 of curved profile destined to adhere in part to the inside surfaces of the lateral bands 23 presented by the front face 7 of the packet 1. Similarly, each side piece 33 of the frame 31 presents a flat central portion 36 destined to adhere in part to the respective inside surface of the flat central portion 14 presented by the relative flank face 9 of the packet 1, and two respective precreased lateral bands 37 of curved profile destined to adhere in part to the inside surfaces of the lateral bands 24 presented by the flank face 9. 0034 The lateral bands 35 presented by the breast piece 32 of the frame 31 are connected to the respective bands 37 of the side pieces 33 by way of respective sharp corner edges 10 extending substantially in vertical alignment with the corner edges 10 of the packet 1. 0035 Each lateral band 35 and 37 is rendered pliable by a respective plurality of longitudinal crease lines, and each corner edge 10 presents a longitudinal U-shaped slot 38 serving to create a respective lip 39 positioned to interact with an internal surface of the lid 5 in such a way that the lid 5 is held stably in the closed position. 0036 It will be seen that the lip 39 projects sideways from the respective lateral band 35 in such a way as to constitute an appendage of the band 35. Thanks to the incorporation of the sharp corner edge 10, the appendage projects from the corresponding band 37 sufficiently to guarantee an effective retaining action on the lid 5 when in the closed position. 0037 Referring to FIG. 4, the packet 1 is fashioned from a flat diecut blank 40 of substantially elongated rectangular outline, of which the parts are denoted where possible using the same numbers, primed, as those used to indicate the corresponding parts of the erected packet 1. 0038 The blank 40 is referable to a predominating longitudinal axis 41 of symmetry and presents two longitudinal crease lines 42 and 43 disposed one on either side of the axis 41, dividing the blank 40 into three longitudinal sectors 44, 45 and 46 lying side by side. The three sectors 44, 45 and 46 are crossed by a plurality of crease lines transverse to the axis 41 and denoted by the numbers 47 to 52. 0039 The middle sector 45 is divided by the transverse crease lines 47 to 52 into: a panel 7a positioned between the lines denoted 47 and 48; a panel 11 between lines 48 and 49; a panel 8a between lines 49 and 50; a panel 8b between lines 50 and 51; a panel 12 between lines 51 and 52, substantially identical to the panel denoted 11; and an end panel 7b joined to the panel denoted 12. 0040 The blank 40 further comprises a plurality of lateral wings 53, 54, 55 and 56 presenting a substantially trapezoidal outline, joined in pairs via the longitudinal crease lines 42 and 43 to the outer edges of the panels 7a, 7b, 8a and 8b, respectively, of which the wings denoted 55 carry longitudinal appendages 57 joined along the transverse crease line denoted 49 and directed toward the wings denoted 53. Similarly, the wings denoted 56 carry longitudinal appendages 58 joined along the transverse crease line denoted 51 and directed toward the wings denoted 54. 0041 The panels 7a and 7b making up the front face 7 and the panels 8a and 8b making up the rear face 8 present respective flat central portions 13 coinciding with the respective flat central portions 13 presented by the front and rear faces 7 and 8 of the packet 1. These same panels 7a, 7b, 8a and 8b present two bands 23, one on each side of the relative central portion 13, coinciding with the lateral bands 23 of the packet 1. 0042 In like manner, the wings 53, 54, 55 and 56 making up the flank faces 9 of the erected packet 1 comprise respective flat portions 14 each forming a part of one respective flat central portion 14 of the flank faces 9 of the packet 1, and a respective precreased longitudinal band 24 interposed between the respective flat portion 14 and the bands 23 of the respective panels 7a, 7b, 8a and 8b to which they are joined along the longitudinal crease lines 42 and 43 destined to become the sharp longitudinal corner edges 10 of the packet 1. 0043 The panel 7a first mentioned is also joined along the first transverse crease line 47 to a reinforcing flap 59 of width substantially equal to the width of the selfsame panel 7a. 0044 Observing FIGS. 5 and 6, it will be seen that the panel 11 coinciding with the top end face 11 of the packet 1 is essentially rectangular and connected to the adjoining panels 7a and 8a along respective rectilinear central portions 15 of the respective longer sides 16, of which the curved end portions 26 are detached from the lateral bands 23 of the selfsame panels 7a and 8a. 0045 In like manner, the panel 12 coinciding with the bottom end face 12 of the packet 1 is essentially rectangular and connected to the adjoining panels 7b and 8b along respective rectilinear central portions 17 of the respective longer sides 18, of which the curved end portions 27 are detached from the lateral bands 23 of the selfsame panels 7b and 8b. 0046 It will be seen also that the longitudinal shorter sides 20 of the one panel 11 are substantially aligned on the longitudinal crease lines 42 and 43 and convexly profiled, each presenting a rectilinear central portion 19 and two curved end portions 28 joined to the corresponding curved end portions 26 of the longer sides by way of the relative sharp corner edge 10. 0047 Similarly, the longitudinal shorter sides 22 of the other panel 12 are substantially aligned on the longitudinal crease lines 42 and 43 and convexly profiled, each presenting a rectilinear central portion 21 and two curved end portions 29 joined to the corresponding curved end portions 27 of the longer sides by way of the relative sharp corner edge 10. 0048 Referring to FIGS. 7 and 7a, it will be seen that the radii of the curved portions denoted 26, and consequently of the portions denoted 27, can differ from the radii of the curved portions denoted 28, and consequently of the portions denoted 29. Accordingly, the width of the relative bands 23 and 24 will vary in proportion. 0049 The hinge 30 coincides with the transverse crease line denoted 50. 0050 The longer wings 54 and 56 will be bent at right angles to the respective panels 7b and 8b with which they are associated. These same panels 7b and 8b are then bent toward one another at right angles to the intermediate panel 12, with the result that the wings 56 of one pair will overlap the wings 54 of the other pair, causing the lateral bands 24 of the selfsame wings 54 and 56 to assume a curved profile relative to the associated flat portions 14 and thus form the flank faces 9b of the container 3, and causing the lateral bands 23 of the panels 7b and 8b likewise to assume a curved profile relative to the flat portions 13 and thus form the front and rear faces 7b and 8b of the container 3. Similarly, the appendages 58 are bent inwards at right angles to the respective wings 56 and rotated together with the wings 56 to the point of engaging the inside surface of the corresponding panel 12, with which they combine to establish the bottom end face 12 of the packet 1. 0051 In like manner, the shorter wings 53 and 55 are bent at right angles to the respective panels 7a and 8a with which they are associated. The flap 59 is bent double against the internal surface of the adjoining panel 7a, whereupon the two panels 7a and 8a are bent toward one another at right angles to the intermediate panel 11 so that the wings 53 of one pair ultimately overlap the wings 55 of the other pair, causing the lateral bands 24 to assume a curved profile in relation to the associated flat portions 14 and thus form the flank faces 9a of the lid 5, and causing the lateral bands 23 of the panels 7a and 8a likewise to assume a curved profile relative to the flat portions 13 and form the front and rear faces 7a and 8a of the lid 5. Similarly, the appendages 57 are bent inwards at right angles to the respective wings 55 and rotated together with the wings 55 to the point of engaging the inside surface of the corresponding panel 11, with which they combine to establish the top end face 11 of the packet 1. 0052 The two longitudinal lines 42 and 43 are creased more forcibly than the lines 25 generating the lateral bands 23 and 24, so that when the diecut blank 40 is bent in the manner described above along these same crease lines 42 and 43, the sharp corner edges 10 of the packet 1 will be formed decisively and without difficulty. 0053 It will be seen that the operations of folding the blank 40 as described above are pertinent only to the container 3 and the lid 5; accordingly, the stiffening frame 31 is prepared preferably by means of separate folding operations and then assembled with the container 3. 0054 In the example of FIGS. 8 and 9, the packet 2 appears as a prismatic solid of substantially triangular cross section, comprising three side faces 60, 61 and 62 of which the two denoted 60 and 61 combine to establish a front face 63, and the remaining side 62 establishes a rear face. The top and the bottom end faces of the packet 2 are denoted 65 and 66 respectively. The side faces 60, 61 and 62 are joined one to the next along respective sharp corner edges 67. 0055 In like manner to the packet 1 described above, the three side faces 60, 61 and 62 of the packet 2 present a convex profile; more exactly, each face comprising a substantially rectangular flat central portion 68 and two longitudinal lateral bands 69 disposed on opposite sides of the relative central portion 68, each joined to the corresponding lateral band 69 of the adjacent face along a relative sharp corner edge 67. 0056 Each band 89 is rendered pliable by longitudinal crease lines 70, so as to assume a curved profile with the concave surface directed toward the inside of the packet 2. 0057 As discernible from FIG. 11, each side of the top end face 65 and of the bottom end face 66 presents a rectilinear portion coinciding with the end of the flat central portion 68 presented by the side faces 60, 61 and 62, and respective curved end portions coinciding with the ends of the lateral bands 69. 0058 Referring to FIG. 10, the packet 2 is fashioned from a flat diecut blank 71 of substantially elongated rectangular outline, of which the parts are denoted where possible using the same numbers, primed, as those used to indicate the corresponding parts of the erected packet 2. 0059 In particular, the flat blank 71 is referable to a predominating transverse axis 72 and presents three mutually parallel precreased bend lines 67 delimiting two panels 60 and 61 making up the front face 63 of the packet 2, a panel 64 coinciding with the rear face 64 of the packet 2, and a connecting panel 73 that will be breasted ultimately in contact with the inside surface of the back panel 64. 0060 The panels 60, 61, 64 and 73 of the blank 71 also presents lateral bands 69 located on either side of each bend line 67 and rendered pliable by crease lines denoted 70. 0061 The blank 71 also presents a transversely placed Vee cut 42 intersecting the three precreased bend lines 67, and more exactly composed of two angled legs 75 converging onto the central precreased bend line 67. The two ends of the cut 74 are joined to respective crease lines 76 extending transversely to the bend lines 67 and functioning as the hinge of the lid 5. 0062 The panel 64 coinciding with the rear face of the packet 2 is associated with a top wing 77 and a bottom wing 78, each joined to the panel 64 along a relative crease line 79. The two wings 77 and 78 are substantially triangular and serve respectively to establish the top end face 65 and the bottom end face 66 of the packet 2. The precreased bands 69 serve to establish respective longitudinal lateral bands 69 designed to assume a curved profile with the concave surface directed toward the inside of the packet 2. 0063 It will be observed that the second packet 2 comprises a frame 80 in like manner to the first, in this instance furnished with two side pieces 81 joined by a central precreased band 82 breasted in contact with the inside surface of the band 69 presented by the front face 63. 0064 The present invention is applicable likewise to containers embodied as cartons, designed to hold a plurality of packets of cigarettes and differing from the packets 1 and 2 described above only in terms of size.