US20070220840A1

US20070220840A1 - Apparatus for wrapping objects

Info

Publication number: US20070220840A1
Application number: US11/384,826
Authority: US
Inventors: Paolo Pecchenini
Original assignee: Robopac SA
Current assignee: Robopac SA
Priority date: 2006-03-21
Filing date: 2006-03-21
Publication date: 2007-09-27
Also published as: WO2007107586A1; EP2001744A1

Abstract

An apparatus for wrapping objects comprises a ring element which is rotatable around a rotating axis and which supports a reel unit arranged for wrapping a film on said objects, said reel unit being associated with a respective cutting device suitable for cutting said film, wherein said apparatus comprises at least a further reel unit supported by said ring element, arranged for wrapping a further film on said objects and cooperating with a further cutting device suitable for cutting said at least further film.

Description

The invention relates to an apparatus for wrapping objects with film in plastics and/or paper material.
Apparatuses are known comprising a ring element that is rotatable around a rotating axis and a supporting reel unit fit for wrapping objects with a stretchable plastic film.
A conveying plane is provided that extends through the ring element and on which objects are advanced along an advancing direction that have to be wrapped with the film, such as for example pipes, elongated elements, wooden or metal profile elements, etc.
The reel unit comprises a support on which a reel of stretchable film is positioned that is arranged parallel to the rotating axis. Near said reel, a tightening roller is provided that is used to keep the film tight during wrapping, and an idle roller, adjacent to the tightening roller and arranged for directing the film onto the object to be wrapped.
A gripping member is provided that is movable parallel to the advancing direction and is arranged to intercept and/or grasp a portion of the film at the end of the wrapping of an object to enable the wrapping of a subsequent object.
A cutting element is arranged for cutting the film, with which a brush element is associated. The cutting element is movable from a first position, in which it does not interfere with the film whilst the latter is wrapped around an object, to a second position, in which it cuts the film, separating it from the object that has just been wrapped. During operation, an object to be wrapped with the film is advanced along the conveying plane so that a first end portion thereof traverses the ring element and is positioned near the reel unit. The ring element starts to rotate and drags with itself the reel unit whilst the gripping member continues to retain an end edge of the film that is progressively unwound from the reel and is wrapped around the object.
After the reel unit has rotated around the object in such manner that the end edge of the film is stably connected to the object, the gripping member disengages from the film and retreats to a rest position.
The object is advanced in the advancing direction whilst the reel unit rotates around the rotating axis so that the film can progressively wrap adjacent zones of the object.
After the surface of the object has been covered by the film completely or partially, the ring element, and therefore the reel unit, stops in a position such as to enable the gripping member to advance to an operating position to intercept and grasp the film.
The cutting element is driven to cut the film in a zone interposed between the gripping member and the object. A further end edge of the film, generated after the cutting, is retained by the gripping member to enable wrapping of a subsequent object.
The brush element acts after the cutting so as to make an end portion of the film adhere to the object. At this point the object is completely wrapped and can be picked up from the apparatus.
A drawback of the known apparatuses is that they do not enable objects to be wrapped in a sufficiently short time as the structural stress to which the apparatuses are subjected imposes limits on the rotating speed with which the ring element and the reel unit move. The structural stress is associated with the dynamic unbalance of the mechanical parts that are movable around the rotating axis, in particular the reel unit.
To reduce this problem counterweights are provided on the ring element that are not able to satisfactorily balance the inertia forces generated by the reel unit and do not therefore enable the apparatus to reach a high speed and thus high productivity.
Another drawback is that the aforementioned known apparatuses do not enable objects to be wrapped with film in different materials, for example paper and plastic film, in order to form wrappings with differentiated strips or layers.
Another drawback is that if there is an undesired break in the film it is necessary to immediately arrest the apparatus to restore correct operation.
An object of the invention is to provide an apparatus that is able to wrap objects in a very short time.
Another object of the invention is to provide an apparatus that is statically and/or dynamically very balanced.
A further object of the invention is to provide an apparatus that is able to wrap objects with film of different materials in a single operation so as to form wrappings with differing strips or layers.
Another object of the invention is to provide an apparatus that is able to terminate the wrapping of an object even if there is an undesired breakage of a film.
According to the invention, an apparatus is provided comprising a ring element which is rotatable around a rotating axis and which supports a reel unit arranged for wrapping a film on objects and cooperating with a cutting device suitable for cutting said film, wherein the apparatus comprises at least a further reel unit supported by said ring element, arranged for wrapping a further film on said objects and cooperating with a further cutting device suitable for cutting said further film.
Owing to the invention it is possible to obtain an apparatus that is able to wrap objects with a film in a very short time.
Owing to the reel unit and to the further reel unit, the apparatus according to the invention in fact enables objects moved at a high advancing speed to be wrapped in a uniform and complete manner, whilst keeping the rotation speed of the ring element limited.
In addition to that, the apparatus enables an object to be wrapped simultaneously with film of different materials so as to form wrappings with distinct strips or layers, for example a layer of paper and a layer of transparent plastics.
As the reel units are fixed to the ring element spaced angularly between them, it is possible to furthermore obtain an apparatus that is statically and/or dynamically very balanced, so that to reduce the structural stress that is generated during operation, also at high rotating speeds.
The apparatus also enables the wrapping of an object to be complete even if an undesired break of one of the films occurs.
The invention can be better understood and carried out with reference to the attached drawings, that illustrate an embodiment thereof by way of non-limitative example, in which:
FIG. 1 is a front view of an apparatus for wrapping objects according to the invention in association with an object to be wrapped;
FIG. 2 is a partial side view of the apparatus in FIG. 1;
FIG. 3 is a view from above of the apparatus in FIG. 1;
FIG. 4 is a perspective view of the apparatus in FIG. 1.
FIGS. 1 to 4 show an apparatus 1 for wrapping objects, comprising a ring element 2 which is rotatably movable around a rotating axis R and which supports a reel unit 3 and further reel unit 4, which are arranged angularly spaced from one another with respect to said rotating axis R. In the example shown in FIGS. 1 to 4 the rotating axis R is horizontal.
The ring element 2 comprises an annular element or wheel that is rotatably supported by a frame 40, for example of a wrapping machine, with which the apparatus 1 can be associated. The ring element 2 is driven by means of a belt 17 connected to a motor 18.
The reel unit 3 and the further reel unit 4 are rotated by the ring element 2 around the rotating axis R so as to wrap objects 50 with stretchable plastic films and/or with sheets of paper or similar material.
It is provided a conveying plane 41 which passes through the ring element 2 and on which the objects to be wrapped are advanced in an advancing direction A, in manual or automatic mode.
The reel unit 3 comprises a support member 21 fixed to said ring element 2 and suitable for supporting a first reel 5 which is arranged substantially parallel to the rotating axis R and on which is wound a film 25.
The reel unit 3 comprises a tightening arrangement 7, 8 suitable for keeping said film 25 stretched tight during wrapping of an object 50. Said tightening arrangement includes a first tightening roller 7, provided with a clutch device, and a first guide roller 8, arranged for directing the film 25 onto the object 50.
The further reel unit 4 comprises a further support member 22 suitable for supporting a further reel 6 which is arranged parallel to the rotating axis R and on which is wrapped a further film 26.
The further reel unit 4 includes a further tightening arrangement 9, 10 provided for keeping said further film 26 stretched tight during wrapping of an object 50. Said further tightening arrangement comprises a further tightening roller 9, provided with a clutch device, and a further guide roller 10, arranged for suitably directing the further film 26 onto the object 50.
The apparatus is provided with a gripping member 11 that is movable and suitable for interacting with said film 25 that is unwound from the first reel 5.
A further gripping member 12 is provided for acting with the further film 26 that is unwound from the second reel 6.
The gripping members 11, 12 are of the known type and comprise for example respective grippers, which are arranged angularly spaced with respect to the rotating axis R, at the respective reels 5, 6 for clamping portions of the respective films 25, 26.
In an embodiment of the apparatus 1 that is not shown, the gripping members 11, 12 may comprise respective elongated rods, provided with ends arranged for abutting on and hooking edges of the respective films 25, 26.
The gripping members 11, 12 are movable substantially parallel to the advancing direction A from a rest position, on which they are on an opposite side from said reels 5, 6 with respect to the ring element 2, to an operating position, in which they project through the ring element 2 so as to be positioned near the reels 5, 6.
The apparatus 1 comprises a cutting device 15 suitable for cutting the film 25 that is unwound from the reel unit 3 at the end of the wrapping of an object 50. A further cutting device 16 is provided for cutting the further film 26 unwound from the further reel unit 4.
The cutting device 15 and the further cutting device 16 are arranged angularly spaced with respect to the rotating axis R.
The cutting devices 15, 16 are provided with respective cutting elements 13 and with respective brush elements 14 that can rotate around axes B.
In particular, the cutting devices 15, 16 are driven so as to move from a first position, in which they do not interfere with the films whilst the latter are wrapped onto the object, to a second position in which they acts on the films by separating said films from the object that has just been wrapped. The brush elements 14 are used to make the end portions of the films, that are generated after cutting, adhere to the object that has just been wrapped.
In an embodiment of the apparatus not shown, the cutting devices 15, 16 are fixed with the respective gripping members 11, 12 consisting of the aforementioned movable elongated rods. In this embodiment, the cutting devices comprise respective fixed blades that are suitable for cutting the films that are grasped and dragged by the gripping members in the rest position.
In the embodiment shown in the figures, the apparatus 1 comprises two reels, a first reel 5 and a second reel 6, associated with corresponding tightening arrangements 7, 8, 9, 10, cutting devices 15, 16 and gripping members 11, 12. The apparatus 1 may also comprise three or more reels of film, each reel associated with a respective tightening arrangement, cutting device and gripping member.
In the configuration disclosed above, the reel unit 3 and the further reel unit 4 are arranged spaced apart from one another by an angle of 180° with respect to the rotating axis R, i.e. with the first reel 5 and the second reel 6 diametrically opposite with respect to said axis R.
Similarly, the cutting device 15 and the further cutting device 16, the gripping member 11 and the further gripping member 12 are arranged together in diametrically opposite positions with respect to the rotating axis R. This configuration enables the apparatus 1 to be balanced both statically and dynamically, in order to reduce the structural stress thereto that is generated during operation.
If the apparatus 1 comprises, for example, three reels, the latter can be arranged angularly spaced from one another by an angle of 120°.
In the case of a larger number of reels, for example four, the latter can be arranged angularly spaced from one another in different ways to create a statically or dynamically balanced structure.
During operation of the apparatus 1, an object 50 to be wrapped is advanced on the conveying plane 41 so that an end portion thereof is interposed between the reel unit 3 and the further reel unit 4, whilst the gripping member 11 and the further gripping member 12 are in the operating position and respectively keep clamped an end edge of the film 25 and an end edge of the further film 26.
The ring element 2 starts to rotate by moving the reel units 3, 4 around the rotating axis R. During the rotation of the ring element 2, the end edges of films 25, 26 are initially retained by the gripping member 11, 12 so that the films 25, 26 are forced to unwind from the respective reels 5, 6, whilst respective first portions of film are deposited on the object.
After the ring element has been rotated so that the films 25, 26 are stably fixed to the object 50, the gripping members 11, 12 disengage from the films 26, 26 and retract to the rest position.
The stretchable films remain stably wrapped on the object 50 also because they elastically shrink after being tensioned by the tightening rollers.
The object 50 is advanced in the advancing direction A whilst the reel units 3, 4 rotate around the rotating axis R so as to progressively cover the surface of the object with the films in a partial or complete manner.
After the surface of the object has been covered by the films, the ring element 2, and therefore the reel unit 3, 4 are arrested in a position such as to enable the gripping member 11 and the further gripping member 12 to advance to the operating position and respectively grasp the film 25 and the further film 26.
At this point, the cutting device 15 is driven to cut the film 25 in a zone interposed between the gripping member 11 and the object 50, and similarly the further cutting device 16 is driven to cut the further film 26 in a further zone interposed between the further gripping member 12 and the object 50.
The brush elements 14 of each cutting device 15, 16 act so as to make end portions of film 25, 26 that have been generated after cutting adhere completely to the object. At this point the object 50 is wrapped and can be removed from the apparatus 1.
Further end edges of the films 25, 26 are retained by the gripping member 11, 12 to enable a subsequent object to be wrapped.
It should be observed that owing to two or more reels, the apparatus 1 enables the objects 50 to be wrapped with films of different material to arrange superimposed strips, for example a paper film and a transparent plastic film.
In an embodiment of the apparatus 1 that is not shown a vertical operating configuration is provided. In particular, the ring element 2 is arranged in such a way as to be rotatable around a further rotating axis vertically arranged and movable along the latter.
A conveying plane is provided that is used to convey to an operating zone objects that have to be wrapped. In this case, after an object has been positioned in the operating zone, the ring element 2 is driven. The latter moves along the further rotating axis and rotates around the latter by travelling down the object whilst the first reel unit 3 and the second reel unit 4 wrap the film around the object.

Claims

1. Apparatus for wrapping objects comprising a ring element which is rotatable around a rotating axis and which supports a reel unit arranged for wrapping a film on said objects, said reel unit being associated with a respective cutting device suitable for cutting said film, wherein said apparatus comprises at least a further reel unit supported by said ring element, arranged for wrapping a further film on said objects and cooperating with a further cutting device suitable for cutting said further film.

2. Apparatus according to claim 1, wherein said reel unit and said further reel unit are angularly spaced with respect to said rotating axis.

3. Apparatus according to claim 1, wherein said cutting device and said further cutting device are movable around respective axes, which are substantially parallel to said rotating axis.

4. Apparatus according to claim 1, wherein said cutting device and said further cutting device are angularly spaced with respect to said rotating axis.

5. Apparatus according to claim 1, wherein said reel unit comprises a support member fixed to said ring element and suitable for supporting a reel on which is wound said film.

6. Apparatus according to claim 5, wherein said at least further reel unit comprises a further support member suitable for supporting a further reel, on which is wound said further film.

7. Apparatus according to claim 6, wherein said reel and said further reel are substantially parallel to said rotating axis.

8. Apparatus according to claim 1, wherein said reel unit and said further reel unit respectively comprise a tightening arrangement and a further tightening arrangement suitable for tightening said film and said further film.

9. Apparatus according to claim 1, wherein a gripping member is provided that is movable and suitable for interacting with said film.

10. Apparatus according to any one of claim 9, wherein at least a further gripping member is provided that is movable and suitable for interacting with said further film.

11. Apparatus according to claim 10, wherein said gripping member and said further gripping member are movable in a direction that is substantially parallel to said rotating axis.

12. Apparatus according to claim 10, wherein said gripping member and said further gripping member are arranged angularly spaced with respect to said rotating axis.

13. Apparatus according to claim 10, wherein said gripping member and said further gripping member comprise respective grippers suitable for grasping and locking edges of said films.

14. Apparatus according to claim 1, wherein said cutting device and said further cutting device comprise respective cutting elements and respective brush elements.

15. Apparatus according to claim 1, wherein said rotating axis is substantially horizontal and substantially parallel to a conveying plane of said objects.

16. Apparatus according to claim 1, wherein said rotating axis is substantially vertical.

17. Apparatus according to claim 16, wherein said rotating axis is arranged transversely to a conveying plane of said objects.

18. Apparatus according to claim 17, wherein said rotating axis is substantially orthogonal to said conveying plane.

19. Apparatus according to claim 16, wherein said ring element is movable along said rotating axis.