EP3335998B1

EP3335998B1 - Hooding machine with improved structure

Info

Publication number: EP3335998B1
Application number: EP17207977.4A
Authority: EP
Inventors: Massimiliano Ubertini
Original assignee: Messersi Packaging Srl
Current assignee: Messersi Packaging Srl
Priority date: 2016-12-19
Filing date: 2017-12-18
Publication date: 2019-05-15
Anticipated expiration: 2037-12-18
Also published as: TR201909265T4; PT3335998T; EP3335998A1; IT201600127868A1; ES2741879T3; PL3335998T3

Description

The present invention relates to a machine of the so-called "hooding" type, namely a machine which performs the wrapping of a package by fitting from above a hood of plastic film, generally consisting of extendable or heat-shrinkable material.
In the art hooding machines are known where a section of a tube of plastic film or "hood" is prepared, said hood being generally formed by means of transverse cutting and heat-sealing a tube of flattened tube wound up on a reel. The hood, which is obtained with the mouth directed upwards, is conveyed along feed path until it is arranged with the mouth directed downwards and above the package to be wrapped. In a particular type of such machine, the hood, by means of a collecting head, is crimped along its longitudinal axis, while it is fed above the package, and is then stretched transversely taking advantage of the elasticity of the material, so as to open it sufficiently, and is then pulled down and fitted around the package from above, being gradually unrolled as the collecting head, in the form of a rectangular frame, moves down along the package.
A machine of this type is described for example in EP 2,719,628 .
One problem of these known machines is that the transverse dimension of the tube of film is dependent on the structure of the entire machine. For example, while the collecting head is by its nature generally able to be suitably widened transversely, the film travel path is essentially a channel with predefined dimensions. The known machines may therefore be designed at the most, with a certain degree of constructional complexity, so that they can be adapted to a limited and predefined number of formats, for example three formats, as regards the width of the tube of flattened film. Also the conversion from one format to another, even where such a limited number of formats is involved, also requires time and not just simple setting of the machine before being able to resume the hooding operations. In the case, where, for example, there are frequent changes in format, due to the need to pack limited numbers of packages with the same format, before switching to another format, it often becomes advantageous from the point of view of the time needed for adaptation to the change in format, to use different machines, instead of a single machine which must in each case be adapted and adjusted. This has, however, among the various drawbacks, that of increasing the costs owing to the machines required for the different formats to be processed. Moreover, if different machines are used, it is also necessary to increase the number - and hence the complexity - of lines for transporting the packages to and from the machines for the various different formats.
The general object of the present invention is, among other things, that of being able to provide a hooding machine which is flexible as regards the formats which may be processed and of ensuring that the machine settings needed to switch from one format to another may be rapidly performed.
In view of this object, the idea which has occurred is to provide, according to the invention, a hooding machine comprising a system for forming a hood from a tube of film which is in a flattened folded condition so as to form four side edges, this system comprising gripping and pulling means which move along a hood formation path from a starting area of the path, where the tube of film in the folded flattened condition is fed with its initial portion, to an end area of the path where there is a head for collecting, expanding and fitting the hood onto a package, arranged above an area of the machine which is an area for receiving a package to be wrapped, said head being suitable for receiving the hood from the gripping and pulling means and for fitting it onto a package in said package receiving area, characterized in that the gripping and pulling means comprise two pairs of chain rings arranged symmetrically on two opposite sides of the hood formation path and motor-driven so as to travel along said hood formation path, each chain ring having at least one gripper for gripping one of the four side edges of the tube of film near its initial portion so as to pull it along said path, each pair of chain rings being supported on a frame so as to be movable with respect to the other pair of chain rings and thus be able to vary controllably the mutual distance between the pairs of chains and adapt the machine to a different transverse dimension of the tube of film.
In order to illustrate more clearly the innovative principles of the present invention and its advantages compared to the prior art, an example of embodiment applying these principles will be described below with the aid of the accompanying drawings. In the drawings:

Figure 1 shows a schematic side elevation view, from a left-hand side, of the machine according to the invention during a first operating step;
Figure 2 shows a schematic side elevation view, from the right-hand side, of the machine according to Figure 1, but during a second operating step;
Figure 3 shows a schematic plan view of the machine according to the invention;
Figure 4 shows a schematic rear elevation view of the machine according to the invention;
Figures 5, 6 and 7 show enlarged and partial schematic views, i.e. a side elevation, rear elevation and plan view respectively, of an area for gripping a front portion of a tube of film in the machine according to the invention;
Figures 8 and 9 show enlarged schematic views, i.e. a plan view and side elevation, respectively, of grippers present in the machine according to the invention.

With reference to the figures, Figure 1 shows a hooding machine provided according to the invention, indicated generally by 10.
The machine 10 comprises a system 11 for forming a hood from a tube of film 12 which arrives in a flattened folded condition (preferably unrolled from a feed roller). "Flattened folded condition" is understood as meaning that the tube of film is flattened in a first direction transverse to its length (the horizontal direction in Figure 1) so as to become substantially a strip and in such a way as to form four side edges along the sides of the said strip. In order to form the four edges, flattening is performed with the sides of the tube which are folded in pleats inwards. This flattening of the strip can be understood from the illustration in the left-hand part of Figure 3 or, more clearly, also in the right-hand part of Figure 3 where the strip is only partially flattened for the reasons which will become clearer below.
The hood formation system 11 comprises gripping and pulling means which move along a hood formation path from an initial or starting position or area 13 of the path where the tube of film in the flattened folded condition is fed with its initial portion 14. The formation path has an end area or position 15 where there is a head 16 for collecting, expanding and fitting the hood onto a package, said head being arranged above an area 17 of the machine for receiving a package 18 to be wrapped.
As can be seen in Figure 1, the formation path is preferably shaped generally in the form of an inverted L or J, with a first vertical section directed upwards, a second horizontal section and, preferably, a third vertical section directed downwards, as far as the head 16.
The head 16 is of the type known per se and will not shown and described in detail, since it may be easily imagined by the person skilled in the art based on the description provided hitherto. The head 16 is essentially designed to receive the hood from the gripping and pulling means and to fit it onto a package which is situated in the receiving area (for example inserted in this area manually or by means of known transportation systems).
For example, the head comprises a horizontal rectangular frame with at least the four corners which can be controllably moved away from each other so as to be inserted inside the hood and stretch it transversely so that it can be fitted onto the package according to a known system where the hood is first crimped along its length so that it can be positioned in its entirety on the frame 19 by means of motor-driven crimping rollers and then the frame of the head can be moved downwards in order to fit the hood unrolling it from the top downwards onto the package. The four corners of the frame, which are L-shaped, and the motor-driven crimping rollers are for example visible in Figure 3, indicated by 20 and 21 respectively. As can be seen in this figure, the motor-driven rollers are movable so as to be able to be arranged close to the outer wall of the four corners with the hood of film, indicated by 12b in Figure 3, arranged in between.
Considering again mainly Figure 1, the gripping and pulling means comprise two pairs 22a, 22b and 23a, 23b of chain rings which are symmetrically arranged on two opposite right-hand and left-hand sides of the hood formation path, namely along the sides of the tube of film which travels along the hood formation path until it forms the hood.
Figure 1 shows a first side of the machine with the first pair 22a, 22b of chains which travel in a loop between the starting position 13 and the end position 15 of the hood formation path and on one side of the tube of film.
Figure 2 shows the other side of the machine, opposite to the first side, with the second pair 23a, 23b of chains which travel in a loop between the starting position 13 and the end position 15 of the hood formation path and are situated on the opposite side of the tube of film to the first pair.
The two pairs of chains 22a, 22b and 23a and 23b are motor-driven (in a manner which may be easily imagined by the person skilled in the art by means of motors which, for simpler illustration, are not shown in the drawings) so as to travel along the hood formation path and each chain ring carries at least one gripper 24 for gripping one of the four side edges of the tube of film close to its initial portion so as to pull it along the path into the end position 15 for crimping onto the frame of the head 16. Each pair of chain rings 22a, 22b and 23a, 23b is moreover supported on an associated frame, i.e. the frames 25 and 26, so as to be movable with respect to the other pair of chain rings in a direction transverse to the length of the hood formation path and thus be able to vary controllably the mutual distance between the pairs of chains and adapt the machine to a different transverse dimension of the tube of film. Its pairs of chain rings are supported on the facing side frames 25, 26 by means of a plurality of rollers so as to guide the chains during their circular travel movement along the path between the starting point 13 and the arrival point 15.
The frames 25, 26 may also be preferably shaped generally in the form of an inverted L or J, with a first vertical section directed upwards, a second horizontal section and, preferably, a third vertical section directed downwards, as far as the head 16.
The rear view of the machine according to Figure 4 shows in schematic form a general frame of the machine, indicated by 27, and the two frames 26, 27 of the pairs of chains which are displaceable towards or away from each other along horizontal guides 28, advantageously by means of a chain drive 39 and a gearmotor 30.
The drive system and the guides remain parallel to each other and the two frames 26 and 27 remain vertical.
Figures 5, 6 and 7 show enlarged views of the starting area 13 of the path as present on the frame 25. The other frame has a starting area which is substantially the same and a mirror image thereof. Only the area on the frame 25 is therefore described in greater detail, the other frame area being able to be easily imagined based on the description of the first area.
As can be seen from Figures 5, 6 and 7, the frame 25 supports in the starting area two transmission rollers 31a and 31b of the chain 22a and chain 22b, respectively. Two guides 32 and 33 widen slightly the two edges of the tube of film on a same side of the tube of film so as to facilitate gripping of these two edges by two grippers 24 brought by the two chains 22a and 22b into the starting position of the path, as clearly shown again in Figure 5. At the same time, on the other side of the tube of film, the chains 23a and 23b, which travel in synchronism with the chains 22a and 22b, will bring two associated grippers 24 into the same symmetrical position so as to be able to grip the other two side edges of the tube of film.
Actuating devices 34 fixed in the starting position 13 on the two frames 25 and 26 will actuate the grippers for the suitable opening and closing movement.
Advantageously, as can be clearly seen in the enlarged views of Figures 8 and 9, each gripper 24 has a jaw 35 which is fixed onto a link of the associated chain 22 or 23 and second jaw 36, facing the first jaw, which is pushed against the jaw 35 by a spring 37, such that the gripper 24 is normally in its closed position. When the jaw is brought by the associated chain into the vicinity of an actuator 34, the actuator 34 (advantageously an electric or pneumatic linear actuator) pushes with its thrusting end 38 against the actuating part 39 of the jaw 36, opening it against the action of the spring 37.
From Figures 1 and 2 it is clear that the actuating systems 34 are also present in the end position 15 of the path 11 near the head 16 so as to be able to release controllably the hood which reaches this position and thus allow the hood to be picked up by the head, as mentioned above.
During operation of the machine, the grippers which arrive in the starting area 13 therefore grip the four edges or corners of the tube of film, in the vicinity of the initial portion 14, and transport it along the path 11 as far as the end area 15 where they release it so that it may be taken up by the head 16 which crimps onto its frame and then fits it over the package.
As can be clearly seen in Figure 1, the chains of each pair are arranged so as to have their terminal ends along their path (where respective transmission rollers 40a and 40b are present) spaced from each other so as to open the mouth of the hood formed by the tube of film and allow the mouth of the hood to be fitted onto the frame of the head 16.
In order to separate the tube film section and form the hood, a known device 41 for performing cutting and optionally transverse sealing of the tube of film is arranged in the starting area 13, preferably immediately downstream of the gripping zone of the grippers 24.
In this way, the device 41 may be operated when the gripping and transportation means formed by the chains and the corresponding grippers have transported along the path the tube of film over a length which is the desired length of the hood to be formed.
In this way, the hood is separated from the tube of film and the film tube portion situated upstream of the cut becomes a new film tube portion which will form the mouth of the next hood to be formed and will be gripped at the four corners by the next grippers of the chains in order to repeat the cycle.
This is for example shown in Figure 1, where a hood 12b already separated from the tube of film is held at the top by the grippers 24, while a new portion 14 is ready in the area 13 to be gripped by the next grippers 24 (or by the same grippers 24 following completion of the circular path with rotation of the chains).
The hood then continues the movement along the path until it reaches the end position 15, with the mouth at least partially open owing to the separating movement of chains of each pair, so that it may be then gripped by the head as described above. This is shown for example in Figure 2. The movement of the corners of the frame of the head will then completely open the mouth, elastically stretching the film, so as to adjust the mouth to the dimensions suitable for being fitted onto the package.
The cycle may then be repeated with the grippers which grip and pull the tube of film which has the new front portion in the area 13, so as to form a new hood to be fitted onto the next package which will replace in the zone 17 the package which has just been wrapped.
Obviously the length of the path will be suitable for formation of the hood of the desired length.
The number of grippers along each chain may vary from one or more, depending on whether or not it is required to reduce the time needed to bring the grippers back into the starting area 13 after a hood has been conveyed into the end area 15. For example, two grippers may be provided for each chain, said grippers being spaced along the chain so that, while one gripper is located in the release position in the end area 15, the other gripper is already situated or is reaching the pick-up position in the starting area 13. The machine in this way is very fast.
If the format of the tube of film must be changed, it is merely required to remove the tube of film with the previous format and perform the displacement of the two frames of the chains so that they are arranged at the mutual distance suitable for the new format, position the initial portion of the tube of film with the new format in the starting area 13 and start the machine again. It will also be sufficient, if necessary, to adjust consequently the transverse distance of the gripping edges of the head 16.
At this point it is clear how the objects of the invention have been achieved. According to the invention a machine with a fairly simple and strong structure, with few moving parts, may be provided. It is also possible to provide a machine which may be rapidly adapted to changes in format of the tube of film used. The formats which can be used may also vary continuously from a maximum size to a minimum size which depend only on the maximum distance and the minimum distance at which the two frames with the chains may be arranged.
Obviously the description provided above of embodiments applying the innovative principles of the present invention is illustrated by way of example of these principles. The machine may comprise other mechanisms and systems which are known for this type of machine, such as systems for raising the package towards the head above the hooding zone, for example so as to allow the hood to be fitted until arranged underneath the base of the package.
The dimensions and the proportions of the various parts of the machine may also vary depending on the specific practical requirements. For example, the vertical section of the path will be designed so as to be suitable for the maximum height of the packages which are to be processed, and likewise the length of the horizontal section will depend on the corresponding maximum horizontal dimension of the packages which are to be processed, etc.

Claims

Hooding machine (10) comprising a system for forming a hood from a tube of film (12) which is in a flattened folded condition so as to form four side edges, this system comprising gripping and pulling means which move along a hood formation path (11) from a starting area of the path (11), where the tube of film (12) in the folded flattened condition is fed with its initial portion (14), to an end area (15) of the path where there is a head (16) for collecting, expanding and fitting the hood onto a package, arranged above an area (17) of the machine which is an area for receiving a package to be wrapped, said head (16) being suitable for receiving the hood from the gripping and pulling means and for fitting it onto a package in said package receiving area (17), characterized in that the gripping and pulling means comprise two pairs of chain rings (22a, 22b and 23a, 23b) arranged symmetrically on two opposite sides of the hood formation path (11) and motor-driven so as to travel along said hood formation path (11), each chain ring having at least one gripper (24) for gripping one of the four side edges of the tube of film near its initial portion (14) so as to pull it along said path, each pair of chain rings being supported on a frame (25, 26) so as to be movable with respect to the other pair of chain rings and thus be able to vary controllably the mutual distance between the pairs of chains and adapt the machine to a different transverse dimension of the tube of film (12).
Hooding machine according to claim 1, characterized in that downstream of the starting area a device (41) is present for transversely cutting and optionally sealing the tube of film so as to form the hood.
Hooding machine according to claim 1, characterized in that in the end area (15) the two chains of each pair are spaced from each other so as to open a front mouth of the hood.
Hooding machine according to claim 1, characterized in that the grippers (24) comprise a jaw (35) fixed to a chain link and a jaw (36) which is movable from a closed condition to an open condition of the gripper against the action of a spring.
Hooding machine according to claim 1, characterized in that in the starting area (13) and in the end area (15) actuators are present for opening the grippers (24) carried by the pairs of chain rings into these areas.
Hooding machine according to claim 1, characterized in that the head (16) comprises a frame with four corners (20) movable so as to open transversely the mouth of the hood that is fed onto it.
Hooding machine according to claim 1, characterized in that the formation path (11) is shaped generally in the form of an inverted L or J.
Hooding machine according to claim 1, characterized in that the frames (25, 26) for supporting the pairs of chain rings are shaped generally in the form of an inverted L or J.
Hooding machine according to claim 1, characterized in that the head (16) has motor-driven rollers (21) for crimping the hood on the head.