EP1183183B2

EP1183183B2 - Method and apparatus for packaging articles by means of an envelope made of a thermoplastic film

Info

Publication number: EP1183183B2
Application number: EP00954410A
Authority: EP
Inventors: Luca Manini
Original assignee: Macchine Tessili Circolari MATEC SpA
Current assignee: Macchine Tessili Circolari MATEC SpA
Priority date: 1999-05-21
Filing date: 2000-05-22
Publication date: 2009-09-09
Anticipated expiration: 2020-05-22
Also published as: WO2000076848A2; EP1183183B1; EP1183183A2; AU6687500A; ES2207541T3; IT1309850B1; ITPI990031A1; WO2000076848A3

Description

Field of the invention

The present invention relates to a method for packaging articles coming from production lines by means of an envelope made of a film fed continuously that can be welded thermoplastically.
In particular, but not exclusively, the method is suitable for packaging articles such as articles of underwear, like for example stockings, collants, etc.
The invention relates furthermore to a packaging apparatus that carries out this method.

Description of the prior art

Automatic packaging lines are known suitable to form an envelope-like wrapper around a substantially flat article. These packaging lines have the object of making faster the introduction between them of an article to package into an envelope, with respect to the manual introduction, whose production rate is low.
By using a single folded film, two welding lines on opposite sides are sufficient, the third closed edge being obtained by the folded edge, opposite to the opening of the envelope.
The welding lines, made for example by a metal stretched blade heated electrically, cut at the same time the two films at the edges of the envelope.
Existing production lines, that form an envelope around articles being packaged, provide a mechanical element for containing the article and preventing it from contacting the welding blade and the transversal counter-gripper for pinching the film. This mechanical element, even if of minimum thickness, causes an increase of the size of the envelope that is the sum of the size of the mechanical element and of, the article.
DE-A-4 315 284 discloses the features of the preambles of claims 1 and 5.
DE 2 317 257 discloses a machine for packaging articles with two thermoplastic cutting and welding groups arranged according to two orthogonal planes, to form an envelope closed on four sides. The first thermoplastic cutting and welding group provides a couple of gripper that can close up to a minimum distance between them. A shoulder is provided blocking the withrawal of the articles when the web forming the envelope is withdrawn. The article is introduced in the film without crossing the cutting and welding group.

Summary of the invention

It is an object of the present invention to provide a method for making envelope-like packages by means of thermoplastic welding that allows, in a completely automatic way, to make the envelopes around the article without leaving space between the welding line and the article same.
It is another object of the present invention to provide an apparatus that carries out this method.
It is a particular object of the present invention to provide a method for closing automatically the flap of the envelopes thus formed.
These and other objects are achieved by the method for packaging articles according to claim 1 and the apparatus according to claim 5.
In the cutting and welding step any element remains for supporting the article, which hits against the gripper transversal to the feeding direction of the web using the gripper same as blocking means.
Further preferable features of the method according to claim 1 and the apparatus according to claim 5 are defined in the dependent claims.

Brief description of the drawings

Further characteristics and the advantages of the packaging method and apparatus, according to the present invention, will be made clearer with the following description of an embodiment thereof, exemplifying but not limitative, with reference to attached drawings wherein:

figure 1 shows a cross sectional longitudinal view of an apparatus according to the invention that carries out the method for making envelope packages by means of thermoplastic welding;
figure 2 shows a top plan view of the apparatus of figure 1;
figure 3 shows an elevational side transversal view of the thermoplastic cutting/welding means of the apparatus of figures 1 and 2;
figure 4 shows a view from below of the support of the thermoplastic cutting/welding means of figure 3;
figures 5 and 6 show the apparatus of figure 1 in two different steps of the method according to the invention;
figure 7-11 show a device for closing the flap of the envelope-like package.

Description of the preferred embodiments

With reference to figures 1 and 2, an apparatus for packaging articles 10 coming from production lines 20 uses a web 30 of continuous film that can be welded thermoplastically having two continuous wings 31, 32 overlapping each other and a longitudinal edge 33 along which the wings 31 and 32 are foldably connected. Free edge 34 of lower flap 31 exceeds outwardly more than the edge free 35 of the upper flap 32 in order to provide, eventually, an envelope 36 (figure 2) with a closure flap 37.
The apparatus comprises a feeding/drawing back system 40 in a direction 41 having a conveyor 42 of the web operated by relative driven rollers 44 and 45. Downstream of it a conveyor 46 is provided operated by a roller 47, for dragging away an envelope 36 formed after two transversal cuts of web 30 as described hereinafter.
Transversally to the direction 41 a thermoplastic welding mit 50 is provided having a support 51, visible also in figures 3, 4, 5 and 6. The thermoplastic welding is carried out by means of an electrical blade resistance 52 located between a gripper 53 and a counter-gripper 54, formed by relative upper jaws that are aligned vertically with lower jaws 53a and 54a.
The upper jaws of the gripper and counter-gripper 53 and 54 are mounted on guiding sticks 53b and 54b resiliently sliding on a support 55, shown also in figure 5. Support 55, to which cutting and welding blade 52 is integral, is mounted on a slide 56 that moves on guide 56a integral to support frame 51. Two opposite pneumatic cylinders, 57 and 58, respectively integral to the frame 51 and to the support 55, are used for lowering in two times the support 55.
As shown in figure 1, upper jaws 53 and 54 of the gripper and of the counter-gripper are shifted in height and the jaw of the gripper is lower than that of the counter-gripper. The lower jaws 53a and 54a can be raised towards the above, by means of a raising unit 59, being parallel to each other.
Always with reference to figure 1, an opening device 21 is provided at the end of the line 20, shown only in the final part, comprising two jaws distanced in height 21a and 21b on which the lower wing 31 and the upper wing 32 respectively slide, in order to keep them open and allowing the introduction of the article 10 by an introducing device 22 not shown in detail.
The article 10, can be a desired article to be packaged, which can be for example a collant with the relative inner support cardboard and a outer V-folded sheet with pictures printed thereon for containing it such as a sandwich.
The article 10 is inserted between the two jaws 21a and 21b on a support tray 23, integral to a lateral carriage 24 operated by motor 25 and belt 26. The tray 23 can move from the position indicated with the continuous line in figure 1 up to the position indicated with a dotted line, carrying the article 10 up to reaching with its front edge a transversally closed end 38 of the web 30.
When tray 23 is in the forward position, that it has reached moving through the counter-gripper 54 and the gripper 53, the article 10 is passed between the two wings 31 and 32 maintaining them in the shape indicated with a dotted line, and eventually slightly pushing the article 10 against the closed transversal end 38 of web 30.
Then, according to the invention, the tray 23 moves back leaving the article 10 in this position and returns up to the starting position passing through the jaws 21a and 21b of the opening device 21, for receiving another article to be packaged.
As shown in figure 4, then, the first actuator 57 pushes the support 55 towards below along the guide 56a, until the upper jaw of the gripper 53 is closed on the lower jaw 53a, which in the meantime has raised itself. The upper shroud of the counter-gripper 54, being shifted in height, instead, is not yet closed. The guide sticks 53b and 54b are not stressed.
In this position the web 30 can slide without tearing itself moving back by means of a back pulling action carried out by the pinch rollers 44 and 45. This movement allows edge 38 to contact the front edge 10a of article 10, bringing the rear edge 10b thereof to contact gripper 53 with the interposition of wings 31 and 32.
The drawing back continues a bit further for slightly bending article 10, so that the envelope 36 that is formed after the cut as described hereinafter is stretched enough around the article 10 same after releasing.
As shown in figure 5, second actuator 58 pushes the upper jaws of the gripper 53 and of the counter-gripper 54 further below so that they press the web 30 against the lower jaws 53a and 54a, with the extension towards the above of the guide sticks 53b and 54b. At the same time, a further push causes the electrical resistance blade to cross the web 30 thus cutting it along the line 38b and welding the two wings 31 and 32 along this line.
Then, finally, the two actuators 57 and 58 raise again themselves and a new cycle starts. The envelope 36 formed (figure 2) has front edge and rear edge 10a and 10b of the article 10 that are located at a direct contact with the welding lines 38 and 38b, achieving the desired object. The conveyor for dragging away 46 brings forward the envelope 36 in an automatic station 49, shown diagrammatically in figure 2, and described in more detail in figures from 7 to 11 for the closure of flap 37, or alternatively in a station of manual closure.
To this end, with reference to figures 7 and 11, the device 49 for closing automatically the flap 37 of the envelope 36, formed as above described, comprises a guiding support 60 arranged at the side of the conveyor web 46 that carries out the dragging away of the envelopes 36.
On the guiding support, which is inclined with respect to the plane of the envelope 36 and of the conveyor web 42, a carriage 61 slides to which are hinged a first and a second arm 62 and 63 having at an end respectively a first and a second finger 64 and 65 for gripping the flap 37. The second arm 63 is connected through a sliding member to a cam 66, integral to the support 60. A pawl 67 has the function of opening fingers 64 and 65 when the arms 62 and 63 are located in a lowered position. The reciprocation of the carriage 61 is given by a connecting rod 68 operated by a crank 60 operated by a motor 70. By means of the cam 66 the fingers 64 and 65 of arms 62 and 63 follow a trajectory shown in turn in figures from 7 to 10. In particular the first and second finger 64 and 65 move above and under the flap 37 when the arms 62 and 63 are in contact with the pawl 67 (figure 7). Then, while being brought forward by the connecting rod 68 is they slidingly close on the flap 37 (figure 8) raising it from the conveyor for the web, rotating it and arranging it (figure 9) correctly on the envelope with the interposition of an adhesive layer and finally going further on until it is extracted from the fingers same (figure 10).
The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention as defined in the claims. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Claims

A method for packaging articles coming from production lines by means of an envelope made of film fed continuously that can be welded thermoplastically comprising the steps of:
- in a feeding direction arranging at least a web (30) of continuous film that can be welded thermoplastically according to two continuous wings (31,32) overlapping each other in order to present a continuous longitudinal closed edge (33), said folded web having a front end (38) transversally to its feeding direction closed in a previous step;

- arranging thermoplastic cutting and welding means (50,52) transversally to the feeding direction of said web;

- opening apart from each other said wings and introducing between them an article (10) being packaged opposite to said closed longitudinal continuous edge at an opening station located upstream of said thermoplastic cutting and welding means (50,52), said article being introduced on a support tray (23) between said wings;

- carrying said article on said tray (23) with a relative movement through said web (30) up to reaching or overcoming said thermoplastic cutting and welding means (50,52) until a front edge of said article is at said front closed end (38), which has been brought further forward by said tray beyond the thermoplastic cutting and welding means together with the article;

- drawing back said tray upstream of said thermoplastic cutting and welding means towards said loading station, leaving said article at said front closed end;

- at said thermoplastic cutting and welding means, transversal to the feeding direction of the web pinching said folded web by means of a gripper (53) transversal to the feeding direction of the web, leaving said web free of sliding through said gripper;

- pulling said web upstream of said gripper transversal to the feeding direction of the web and drawing back said web that slides through said gripper until a front edge of said article contacts said front closed end;

- further drawing back said web until a rear edge of said article contacts said gripper;

- transversal to its feeding direction cutting and welding said web next to said gripper whereby an envelope (36) is formed closed at three sides about said article;

- dragging away said envelope, further packaging the articles and feeding said cut web, said transversal cutting and welding creating another front closed end for said web.
A method for packaging articles according to claim 1, wherein said step of further drawing back said web (30), until a rear edge of said article contacts said gripper (53) transversal to the feeding direction of the web, comprises a step of stretching said web between said gripper and said front closed end with a slight resilient deformation of said article (10), whereby said cutting and welding are carried out on a line that is located shifted from said front closed end that after the raising of said gripper, after that cutting and welding have been made, said film is close to said article that is again in condition not deformed elastically without causing it to fold or crease.
A method for packaging articles according to claim 1, wherein said cutting and welding of said web (30) transversal to the feeding direction of the web comprises the steps of:
- at the end of said further drawing back said web through said gripper, lowering a counter-gripper (54) transversal to the feeding direction of the web upstream of said gripper (53);

- gripping of said gripper and said counter-gripper on said web, so that said web is stretched between said gripper and said counter-gripper;

- passage of said thermoplastic cutting and welding means (50,52) through said web between said gripper and said counter-gripper for said cutting and welding transversal to the feeding direction of the web;

- opening said gripper and said counter-gripper.
A method for packaging articles according to claim 1, wherein said continuous longitudinal closed edge (33) is obtained with a step selected from the group comprised of:
- longitudinal folding of a single continuous web (30) of double width;

- longitudinal overlapping of two webs with the welding line along a longitudinal side line;

- longitudinal overlapping of two webs of double width with the welding and cutting line along a longitudinal central line, obtaining a double web with accessible wings overlapping each other and that can be opened apart from opposite sides.
An apparatus for packaging articles coming from production lines by means of an envelope made of film fed continuously that can be welded thermoplastically comprising:
- means (40) for feeding and drawing back in a feeding direction at least a web (30) of continuous film that can be welded thermoplastically having two continuous overlapped wings;

- thermoplastic cutting and welding means (50,52) arranged transversally to the feeding direction of said web;

- means (21) for opening apart said wings;

- wherein said means (21) for opening apart the wings (31,32) are arranged between said means (40) for feeding and drawing back and the thermoplastic cutting and welding means (50,52), the following being furthermore provided:

- support means (23) of said article (10) at the level of said means for opening apart the wings, said support means being located between the wings of said web (30);

- means (25, 26) for moving said support means along said web between said means for opening apart the wings and a position downstream of said thermoplastic cutting and welding means and viceversa, sliding through said wings;

- a gripper (53) transversal to the feeding direction of said web provided at the level of said thermoplastic cutting and welding means,

- means (55, 56a, 57) for closing said gripper on said web leaving it free of sliding if pulled back from said means for drawing back;

- means (46) for dragging away an envelope (36) formed downstream said thermoplastic cutting and welding means about said article after two consecutive cuts transversal to the feeding direction of the web.
Apparatus according to claim 6, wherein said means for feeding and drawing back comprise means (44,45) for pulling back said web (30) for a predetermined length.
Apparatus according to claim 6, wherein a counter-gripper (54) transversal to the feeding direction of the web is provided upstream of said gripper (53), said thermoplastic cutting and welding means (52) being located between said gripper and said counter-gripper.
Apparatus according to claim 6, wherein said gripper (53) and said counter-gripper (54) are formed by a couple of lower parallel jaws (53a, 54a) and a couple of upper parallel jaws, means being provided for raising said lower jaws and for lowering said upper jaws, said means for raising and for lowering carrying out in turn the closure of said gripper and then of said counter-gripper, said means for drawling back (44,45) operating in the interval between the closure of said gripper and of said counter-gripper.