GB2293571A

GB2293571A - Stabilizing the fold of an oblique reinforcement flap

Info

Publication number: GB2293571A
Application number: GB9518934A
Authority: GB
Inventors: Antonio Gamberini; Giordano Gamberini
Original assignee: GD SpA
Current assignee: GD SpA
Priority date: 1994-09-30
Filing date: 1995-09-15
Publication date: 1996-04-03
Anticipated expiration: 2015-09-15
Also published as: ITBO940431A0; GB2293571B; GB9518934D0; IT1274046B; ITBO940431A1

Abstract

A device for stabilizing a reinforcement flap 13 of a blank 3 with a fold 12 at an oblique angle comprises two contrarotating rollers 20, 21 with peripheral die surfaces 26, 27, at least one of which 26 is shaped so as only to compress a small part of the flap adjacent to the fold when bearing against the other surface. Preferably the shaped surface comprises a recessed area connected to the remainder of the surface by a shoulder extending helically around the axis of the roller. The passage width between the surfaces is preferably marginally less than twice the thickness of the single blank. <IMAGE>

Description

A device for stabilizing oblique reinforcement flaps on die-cut blanks for cigarette packets of the rigid type with a hinged lid.

The present invention relates to a device for the stabilization of oblique reinforcement flaps on die-cut blanks for cigarette packets of the rigid type having a hinged lid.

Wrapping methods adopted currently in the tobacco industry embrace the fabrication of hinged lid type cigarette packets in which the lid itself comprises a front face with a free edge that exhibits a first and a second oblique portion, mutually convergent, also an oblique reinforcing flap associated with the first oblique portion of the free edge and bent double so as to lie flat against the reverse side of the front face.

The process of manufacturing a typical hinged lid cigarette packet comprises the steps of folding the reinforcement flap flat against the reverse side of the front face and then stabilizing the flap in the folded position by means of a device as disclosed in US Patent 5,316,537, that is to say, of a type comprising two mutually opposed cylindrical rollers stationed to one side of a conveyor carrying the blanks, rotatable about respective axes extending transversely to the feed direction of the conveyor, and designed to sandwich and compress a portion of each advancing blank compassing at least a part of the aforementioned front face of the lid, which is positioned in such a way as to project laterally from the conveyor.

Whilst the conventional device outlined above is entirely suitable for stabilizing the reinforcement flap of a standard packet, i.e. with a lid of which the flap is bent double along a fold line parallel to the feed direction of the conveyor carrying the blank, it is unable to stabilize a flap bent double along a fold line disposed obliquely to the feed direction of the conveyor without causing the front face to deform against the reinforcement flap and thus rendering the flap visible from the outside.

In the former instance, more exactly, the sections of the flap taken up progressively between the two rollers remain constant with respect to the rolling surfaces, in terms of shape and position, so that the pressure of the stabilizing action applied by the rollers remains constant along all points of each section and the aforementioned deformation can be avoided. In the latter instance, conversely, the sections of the flap taken up progressively between the two rollers will vary in shape and position, so that the pressure of the stabilizing action applied by the rollers must also vary from point to point along each section, and more especially at the end of each section farthest from the fold line.

Thus it happens that even when the two rollers are set apart at the maximum distance commensurate with application of the necessary stabilizing pressure to the fold, it is still not possible in the case of an oblique reinforcement flap to avoid deforming the front face of the lid against the flap.

The object of the present invention is to provide a stabilizing device suitable for use in conjunction with oblique reinforcement flaps and devoid of the drawback described above.

The stated object is duly realized, according to the present invention, in a device for stabilizing oblique reinforcement flaps on die-cut blanks as utilized to fashion cigarette packets of the rigid type with a hinged lid, wherein the single flap is bent double along a fold line extending obliquely with respect to a longitudinal axis of the relative blank and substantially flattened against an end portion of the blank serving to establish the front face of a relative lid: such a device comprises conveyor means by which the blanks are advanced singly and in succession along a path extending at right angles to their longitudinal axes and with the respective end portions projecting laterally from the conveying surface, also a stabilizer unit stationed along the conveying path and in its turn comprising two mutually opposed pressure rollers rotatable about axes disposed transversely to the conveying direction and affording active peripheral surfaces positioned to intercept and pinch the projecting end portion of each successive blank, and is characterized in that at least one of the active peripheral surfaces is shaped in such a way that a relatively small part only of each oblique flap, disposed adjacent to the relative fold line, will be compressed against the other active surface during operation.

In a preferred embodiment of the device disclosed, the two active surfaces are cylindrical surfaces, disposed coaxially with the transversely disposed axes of the respective rollers1 which combine to establish a passage of width marginally less than twice the thickness of the single blank.

To advantage, at least one of the active surfaces comprises at least one recessed area connected to the remainder of the surface by way of a shoulder extending helically around the axis of the relative roller in such a way as to furnish the selfsame active surface with a helical rim directed toward the conveyor means.

The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which: - fig 1 schematically illustrates a preferred embodiment of the device according to the present invention, viewed in perspective and with parts omitted for clarity; - fig 2 shows the device of fig 1 in a plan view, with parts omitted for clarity; - fig 3 is a perspective view of a rigid cigarette packet with a hinged lid fashioned from a die-cut blank as illustrated in figs 1 and 2.

With reference to fig 1 of the drawings, 1 denotes an intermediate portion, in its entirety, of a wrapping machine (not illustrated) by which groups of cigarettes (not illustrated) are enveloped in packets 2 (see fig 3) fashioned from respective flat die-cut blanks 2 (figs 1 and 2) advanced in succession by a conveyor 4 along a feed direction 5 transverse to a longitudinal axis 6 of the blank 3.

Observing fig 2 in particular, the single blank 3 is of substantially rectangular shape and comprises an end portion 7 which in turn comprises a panel 8 compassed on the one side by a fold line 9 disposed transversely to the longitudinal axis 6 and on the opposite side by a free edge 10. The free edge 10 appears as a broken line extending substantially in a transverse direction relative to the longitudinal axis 6 and comprising a first oblique portion 11, also a further oblique portion extending along a fold line 12 angled in relation to the transverse fold line 9 and in the opposite direction to the first portion 11, with which it forms an obtuse angle directed toward the transverse fold line 9.

The end portion 7 also comprises a flap denoted 13, substantially rectangular in shape and obliquely disposed, of which one longer side edge is joined permanently to the panel 8 along the oblique fold line 12.

As discernible from fig 3, the panel 8 incorporates the front face 14 of a hinged lid 15 forming an integral part of the packet 2, and the flap 13 is folded flat against the reverse side of the front face 15 to provide a reinforcement 16 for the free edge 10.

As indicated in figs 1 and 2, die-cut blanks 3 are directed by the conveyor 4 singly and in succession along the feed direction 5 with the relative end portions 7 projecting in part beyond one lateral edge 17 of the selfsame conveyor 4, in such a way that each successive end portion 7 is brought into contact with a stabilizer unit 18 combining with the conveyor 4 to create a stabilizing device 19 by which the flap 13 is rendered stable in a position folded double and flattened against a surface of the panel 8 directed toward the conveyor 4.

The unit 18 is installed in a fixed position at a given point along the conveyor 4, and comprises two die rollers 20 and 21 disposed on opposite sides of the plane P occupied by the end portions 7 of the blanks 2 throughout their progress along the feed direction 5. The rollers 20 and 21 are carried by a relative support (not indicated) and rotatable with respect thereto about corresponding axes 22 and 23 disposed mutually parallel and transversely to the feed direction 5; in particular, the two rollers 20 and 21 comprise one power driven member, and are coupled together tangentially through the agency of respective gears 24 and 25 engaged in mesh and set in rotation about the respective roller axes 22 and 23 at a speed such that the peripheral velocity of the rollers will be matched to the linear velocity of the conveyor 4.The two rollers 20 and 21 also exhibit respective peripheral die surfaces 26 and 27 separated tangentially by a gap or passage 3a of which the width is marginally less than twice the thickness of the single blank 3.

As illustrated to best advantage in fig 1, the one die surface 26 consists in a cylindrical surface centred coaxially on one roller axis 22, whilst the other surface 27 consists in a cylindrical surface centred on the remaining roller axis 23, though in this instance with at least one recessed area 28 appearing substantially triangular when viewed in plan. More precisely, the triangular area 28 is compassed on one side by the frontal surface 29 of the roller 21 nearest to and directed toward the conveyor 4, and connects with the main cylindrical surface 27 by way of a first shoulder 30 departing from the frontal surface 29 and extending parallel with the roller axis 23, and a second shoulder 31 departing from the frontal surface 29 and extending helically about the roller axis 23 to connect with the end of the first shoulder 30 remote from the frontal surface 29.The second shoulder 31 serves to furnish the relative surface 27 with a helical rim 32 directed toward the conveyor 4 and of length greater than that of the oblique fold line 12.

Observing figs 1 and 2, the unit 18 is positioned laterally and externally of the conveyor 4 so that the end portion 7 of each successive blank 3 enters the gap 3a between the two die surfaces 26 and 27, the rollers 20 and 21 being timed to rotate in such a way that when the axis 6 of the blank coincides with a plane perpendicular to the conveyor 4 and occupied by the roller axes 22 and 23, as in fig 2, the recessed area 28 will be positioned facing the end portion 7, with the helical rim 32 developable on the plane occupied by the blank 3 in a direction parallel to the fold line 12, extending along the flap 13 at a distance from the line 12 less than the width of the flap itself. In this way, only a part of the flap 13 is compressed between the die surfaces 26 and 27, and more exactly a strip 33 of constant and relatively slender width, which will be subjected to a substantially uniform pressure without occasioning any deformation of the panel 8.

Claims

1) A device for stabilizing oblique reinforcement flaps on die-cut blanks for cigarette packets of the rigid type with a hinged lid, wherein the single flap is bent double along a fold line extending obliquely with respect to a longitudinal axis of the relative blank and substantially flattened against an end portion of the blank serving to establish the front face of a relative lid, comprising conveyor means by which the blanks are advanced singly and in succession along a path extending at right angles to their longitudinal axes and with the relative end portions projecting laterally from the conveying surface, also a stabilizer unit stationed along the conveying path and in its turn comprising two mutually opposed pressure rollers rotatable about axes disposed transversely to the conveying direction and affording active peripheral surfaces positioned to intercept and pinch the projecting end portion of each successive blank, characterized in that at least one of the active peripheral surfaces is shaped in such a way that a relatively small part only of each oblique flap, disposed adjacent to the relative oblique fold line, will be compressed against the other active surface during operation.

2) A device as in claim 1, wherein the active surfaces are cylindrical surfaces, disposed coaxially with the transversely disposed axes of the respective rollers and combining to establish a passage of width marginally less than twice the thickness of the single blank.

3) A device as in claim 1, wherein at least one of the active surfaces comprises at least one recessed area connected to the remainder of the surface by way of a shoulder extending helically around the axis of the relative roller in such a way as to furnish the selfsame active surface with a helical rim directed toward the conveyor means.

4) A device as in claim 3, wherein the helical rim is of length greater than that of an oblique fold line exhibited by the end portion of the blank.

5) A device as in claim 3 or 4, wherein the recessed area appears substantially triangular in plan and is compassed on one side by a frontal surface of the relative roller.

6) A device as in claim 5, wherein the recessed area is connected to the remainder of the active surface by way of a helical shoulder and a further shoulder of which respective first ends coincide with the frontal surface of the roller and respective second ends are joined together.

7) A device as in claim 6, wherein the further shoulder extends parallel to the axis of the relative roller.

8) A device as in preceding claims, wherein the two rollers comprise at least one power driven member and are coupled together tangentially through the agency of respective gears engaged in mesh and set in rotation at a speed such that the peripheral velocity of the rollers is matched to the linear velocity of the conveyor means.

9) A device for stabilizing oblique reinforcement flaps on die-cut blanks for cigarette packets of the rigid type with a hinged lid, substantially as described with reference to the accompanying drawings.