Patent Grant
7328553
This application claims priority to Italian Patent Application No. BO2004A 000598, filed Sep. 27, 2004, which is incorporated by reference herein.
The present invention relates to a unit for overwrapping products, packets in particular, and to a relative overwrapping method.
The invention finds application to advantage in the tobacco industry, where sheets of transparent material obtained from a continuous strip are used to overwrap packets of tobacco products, typically packets of cigarettes, to which reference is made explicitly in the following specification albeit implying no limitation in general scope.
More particularly, the present invention relates to a unit for overwrapping packets substantially of rectangular prismatic shape delimited axially by two end faces, and laterally by two larger faces and two smaller faces extending parallel to the longitudinal axis of the rectangular prism.
An overwrapping unit of the type in question comprises a feed device dispensing single wrapping sheets cut from a decoiling roll of continuous strip material, and the operation of overwrapping the packets is accomplished as the packets advance along a predetermined wrapping path, utilizing a plurality of folder mechanisms by which each packet is enveloped completely in a respective sheet.
Given the high output speeds of modern cigarette makers and packers, to which overwrapping units of the above noted type are linked, there is a growing need, if the overwrapped products are to emerge free of imperfections, for the single sheets of overwrapping material to be kept continuously and fully under control along the entire wrapping path and throughout the successive operations performed by the folder mechanisms, so as to avoid any possibility of a misalignment between the packet and the sheet, or a portion of the sheet, that could result in the finished overwrap presenting unsightly creases or blemishes.
Importantly, this need for complete control over the sheets is especially evident along stretches of the wrapping line that extend between areas where successive folder mechanisms operate, and more precisely along the stretches where, with the overwrap still not fully formed, one or more parts of the sheet still project freely and have yet to undergo the action of a fold-making element.
The object of the present invention is to provide a unit for overwrapping packets such as will meet the requirements indicated above, while operating at the high output speeds of which modern cigarette makers and packers are capable.
The stated object is realized according to the present invention in a unit for overwrapping packets of substantially rectangular prismatic shape presenting two larger side faces parallel one with another and with a longitudinal axis, two smaller flank faces disposed parallel to the longitudinal axis and normal to the larger faces, and two end faces normal to the longitudinal axis, comprising a first folding conveyor rotatable about a relative axis and performing the initial steps of an operation whereby a sheet of wrapping material is folded around the side and flank faces of the packet; a plurality of holder mechanisms mounted peripherally to the first folding conveyor, each pivotable about a respective axis parallel to the axis of rotation and serving to support respective single packets disposed with the longitudinal axis parallel to the selfsame axis; means associated with each of the holder mechanisms, by which to grip and retain a first end of the sheet; means associated with each of the holder mechanisms, by which to hold and restrain a second end of the sheet; and a second folding conveyor rotatable about an axis parallel to the axis of the first folding conveyor, by which the operation of wrapping the sheet around the four side and flank faces of the packet is completed.
The stated object is realized similarly in a method according to the present invention for overwrapping packets of substantially rectangular prismatic geometry, including the steps of feeding single packets to rotating holder mechanisms of a first folding wheel, in such a way that each packet is positioned with its longitudinal axis parallel to the axis of rotation of the first folding wheel; gripping each packet by two faces disposed transversely to the axis of rotation of the first folding wheel; feeding a sheet of wrapping material to each holder mechanism; pinning a first end of the sheet to the mechanism; effecting initial folding steps, by which the sheet is wrapped around the side and flank faces of the packet; holding and restraining a second free end of the sheet on the mechanism; and transferring the packet and the sheet to a second folding wheel.
The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which:
With reference to
As illustrated in
The unit 1 comprises a substantially horizontal infeed conveyor 9 by which packets 2 are carried in ordered succession along a direction denoted 10, advancing on edge, that is to say with one flank face 7 resting on the infeed conveyor 9, and with the longitudinal axis 5 set transversely to the feed direction 10.
The unit 1 further comprises a transfer wheel 11 set in rotation clockwise (as viewed in
Also forming part of the unit 1 is a second folding conveyor 19, embodied as a second wheel 20 set in rotation clockwise about an axis 21 parallel to the axis 12 of the transfer wheel 11, onto which the packets 2 are taken up edgewise together with the relative sheets 3 folded to the “L” profile, and the sheets 3 thereupon bent further to form a tubular wrap enveloping each packet 2 and aligned on the relative longitudinal axis 5, employing a sequence of steps as described and illustrated in publication EP 1 260 442, to which reference may be made for a full description.
Proceeding beyond the second conveyor 19, the tubular wraps are closed and sealed in conventional manner and the overwrapped packets 2 are directed onto an outfeed conveyor (not illustrated) of the unit 1.
The infeed conveyor 9, the transfer wheel 11 and the first and second folding wheels 14 and 20 are mounted to a frame 25 of the unit 1, and combine to establish a wrapping path P that describes a substantially sinusoidal trajectory.
The transfer wheel 11, which turns substantially tangential to the infeed conveyor 9, comprises a power driven disc 26 centered on and rotatable about the axis 12 of the wheel 11, and, mounted to the disc 26, a plurality of gripping heads 27 spaced apart uniformly about the axis 12 and caused by a cam device of familiar type, not illustrated in the drawings, to pivot on respective axes 28 parallel to the selfsame axis 12. The gripping heads 27 are described in publication EP 1 260 442 mentioned above.
Each gripping head 27 comprises a respective gripper 29 projecting radially from the disc 26 and including two jaws 30 capable of movement one relative to another in a direction transverse to the radial direction, induced by actuator means of conventional embodiment (not illustrated), between an open condition and a closed condition.
When in the closed condition, the jaws 30 of the gripper 29 afford a slot 31 in which to accommodate a packet 2 disposed with one flank face 7 directed toward the axis 12 of the wheel 11 and the two larger side faces 6 in contact with the selfsame jaws 30.
In operation, with the transfer wheel 11 set in rotation, each packet 2 advancing along the infeed conveyor 9 will be picked up by a gripper 29 and then released to the first folding conveyor 13 at the transfer station 16, substantially as indicated in the aforementioned publication EP 1 260 442, to which reference can again be made for a complete description.
The first folding wheel 14 is equipped with a plurality of holder mechanisms 32 equispaced around the periphery, each pivotable about a respective axis 33 extending parallel to the axis 15 of the wheel 14 and serving to support a single packet 2.
As illustrated in
Mounted to the flat face 37 of the aforementioned first block 34, near to one longitudinal edge 38, is a substantially parallelepiped second block 39 of which one face 40, parallel to the flat face 37, functions as a fixed jaw interacting with means 41 pivotable about an axis 42 parallel to the axis 33 of the mechanism and serving to grip and retain a first end of the sheet 3.
The gripping and retaining means 41 appear as a lever with two arms denoted 41a and 41b, presenting a plurality of fingers 43 and capable of movement between a position of disengagement from the fixed face 40 and a position substantially of contact with the selfsame face (see
Movement of the gripping and retaining means 41 between the aforementioned positions is induced by respective actuator means of conventional type, not illustrated, acting on the arm denoted 41a.
As illustrated in
Referring to
Associated rigidly with a face 50 of each contact end 49 directed toward the first block 34, is a first plate 51 projecting toward the opposite contact end 49 and designed, when the jaws 45 are closed, to engage the side face 6 of the packet 2 directed toward the flat face 37 of the block 34.
Each jaw 45 carries a fulcrum pivot 52 extending parallel to the aforementioned axis 47, and a clamp element 53 mounted at an intermediate point to the pivot 52, consisting in a lever with two arms 53a and 53b of which the latter arm 53b presents a second plate 54 at the free end, combining with the first plate 51 to pinch and restrain the packet 2.
In particular, during the closing movement of the gripping and supporting means 44, the free end of the arm denoted 53a is engaged and checked by a fixed stop 55 that induces an angular movement of the clamp element 53 about the pivot 52 against the action of a coil spring (of conventional type, not illustrated) wound around the pivot 52, between a position of disengagement illustrated in
It will be seen moreover that the first plate 51 is separated from the flat face 37 by a given distance D in such a way as to create a void 56, for reasons of access that will become apparent in due course.
It will be seen also, in
The aforementioned portion 36a of the cylindrical surface 36 combines with the suction holes 58 to provide means by which a second end of the sheet 3 is held and restrained.
In operation, with the transfer wheel 11 and the first folding wheel 14 set in rotation about their respective axes 12 and 15, each single packet 2 is released by a gripping head 27 to a corresponding holder mechanism 32 at the transfer station 16, as the jaws 30 of the gripper 29 are distanced from the larger faces 6 and the jaws 45 of the gripping and supporting means 44 simultaneously close on the two end faces 8 of the packet 2.
As the packet advances to the next station 17, a sheet 3 of film is supplied by the feed unit 18 to the relative holder mechanism 32, and pinned at the first end by the gripping and retaining means 41.
As the folding wheel 14 rotates on its axis 15 and the holder mechanism 32 is caused at the same time to pivot on its own axis 33 by actuator means of conventional type (not illustrated), the sheet 3 encounters a fixed restraint 59 of curved profile, substantially concentric with the wheel 14 and presenting an internal surface 59a with suction holes 59b connected to a source of negative pressure (not indicated), by which it is drawn flat progressively against the larger side face 6 of the packet 2 located farther from the flat face 37 of the block 34 and then bent over the adjoining flank face 7 to assume an “L” profile.
The restraint 59, the relative surface 59a and the suction holes 59b combine to establish fixed folder means.
At the point of exit from the fixed restraint 59, the second part of the sheet 3 is attracted to the aforementioned portion 36a presented by the cylindrical surface 36 of the first block 34, and held by suction generated through the holes 58.
As the folding wheel 14 continues to rotate, the holder mechanism 32 in question advances beyond the point of exit from the restraint 59 and into a station 60 at which the packet 2 is transferred to the second folding wheel 20, which is equipped with a plurality of pivoting U-shaped pockets 61 each presenting a back wall 62 and two side members 63.
As it passes through the transfer station 60, the packet 2 is directed gradually from the holder mechanism 32 into the pocket 61. During the course of the transfer, as discernible in
To advantage, the holding and restraining means afforded by the holes 58 generate an aspirating action on the trailing part of the sheet 3 such as will attract the selfsame sheet and ensure that it remains perfectly under control when smoothed by the side member 63 of the pocket 61 against the relative side face 6 of the packet 2, and when sliding over the aspirating portion 36a of the cylindrical surface 36.
The step that takes place on the second folding wheel 20, in familiar manner, is that of completing and securing the tubular wrap around the packet 2.
| Number | Date | Country | Kind |
|---|---|---|---|
| BO2004A0598 | Sep 2004 | IT | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3543471 | Youngman | Dec 1970 | A |
| 5301489 | Benedetti | Apr 1994 | A |
| 5305580 | Draghetti | Apr 1994 | A |
| 6324817 | Ghini et al. | Dec 2001 | B1 |
| 6470651 | Polazzi | Oct 2002 | B1 |
| 6643996 | Spatafora | Nov 2003 | B2 |
| 20020189207 | Spatafora | Dec 2002 | A1 |
| 20030205025 | Spatafora | Nov 2003 | A1 |
| Number | Date | Country |
|---|---|---|
| 1052171 | Nov 2000 | EP |
| 1260442 | Nov 2002 | EP |
| 1361158 | Nov 2003 | EP |
| 1260442 | Nov 2004 | EP |
| 2010769 | Jul 1979 | GB |
| WO 0047474 | Aug 2000 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20060064944 A1 | Mar 2006 | US |
