WO2014016510A1

WO2014016510A1 - Method and machine to form capsules containing a fluid

Info

Publication number: WO2014016510A1
Application number: PCT/FR2013/051773
Authority: WO
Inventors: David Delhaye; Jean-Baptiste CROUE; Antoine BASTIEN; Régis BIGOT
Original assignee: Polytek Innovations
Priority date: 2012-07-27
Filing date: 2013-07-23
Publication date: 2014-01-30
Also published as: FR2993864A1; FR2993864B1

Abstract

According to a method of producing capsules (16) containing a fluid, a step-by-step method comprises the following steps: receipt of two sheets (11, 12) of thermoplastic film, each sheet (11, 12) comprising at least one column (14a, 14b, 14c, 14d) of shaped cavities (10); movement of the two sheets (11, 12) to align the respective cavities (10) of each sheet and gapping of the sheets (11, 12) via pairs of bars (301, 302, 303) which successively clamp the sheets (11, 12) on each side of the pairs of columns of cavities (10), filling of the pocket delimited between the two pairs of bars (301, 302, 303) with fluid to fill the cavities (10), welding of the sheets (11, 12) around the cavities (10) to form the capsules (16). Machine implementing the method

Description

Method and machine for forming capsules containing a fluid

DESCRIPTION

Technical area

The present invention relates to a method and a machine for manufacturing capsules or beads containing a fluid. It applies in particular but not exclusively to paintballs used in militant training or military games.

In the description below, references in brackets ([]) refer to the list of references at the end of the text.

State of its technique

For the purposes of the present invention, a ball of marking paint is understood to mean a capsule generally of spherical shape, which comprises an envelope and a marking paint composition contained in this envelope.

In this context, the nature of the material constituting the envelope and its dimensional characteristics (in particular the thickness) must be such that the impact caused by a ball on a target causes the envelope to burst and to spread out. of the marking paint composition on the target, indicating that it has been reached.

At present, such a ball is made with a gelatin envelope according to a known method conventionally used for the manufacture of medicaments. This method comprises forming by thermoforming two hemispheres, which are joined together by welding, while the marking composition is introduced into the cavity delimited by the two hemispheres. This ball, however, poses many problems related to the nature of the envelope.

Indeed, since the gelatin is of animal origin, its preparation is delicate and it is difficult to obtain a constant and reproducible composition. In addition, the manufacture of gelatin beads must be carried out under controlled atmospheric conditions because of the high sensitivity of the gelatin to moisture and temperature. This is usually manifested as tallow: from a certain moisture level, the gelatin softens, while at high temperature, it tends to dry. Moreover, in case of frost. the water contained in the gelatin crystallizes, which has the consequence that the gelatin loses some of its mechanical properties.

Finally, the sensitivity of gelatin to moisture requires the use of non-aqueous solvent-based paint compositions such as ethylene glycol, polyethylene glycol or polypropylene glycol. These non-aqueous paint compositions are generally in the form of viscous gels and contain solvents which are absolutely not environmentally friendly.

The applicant has proposed in WO2009 / 074732 A1 [1] a ball whose envelope is made of an oxo-biodegradable thermoplastic material. Thus the shell can remain in nature without consequence for the environment, since it can disappear naturally without leaving a trace. However, the manufacturing method requires the use of a high temperature paint composition so that the thermoforming can be performed in the same operation as the filling.

The invention therefore aims to provide a method and a machine for manufacturing capsules or beads for using a non-moisture sensitive material for the casing independently of the material for the filling fluid. Description of the invention

With these objectives in view, the subject of the invention is a process for manufacturing capsules containing a fluid, in which the following steps are carried out:

- Receipt of two sheets of thermoplastic film, each pan having at least one column of cavities formed;

- bringing together the two faces to match the respective cavities of each pan;

filling the cavities with the fluid;

soldering the flaps around the cavities to form the capsules;

characterized in that it proceeds in steps, and at the step of approaching, the plates are sliced by pairs of bars which successively pinch His sides on either side of the columns of cavities, and in the filling step, the pocket defined between two pairs of bars is filled.

The method as proposed makes it possible to separate the filling step and the cavity forming step, such as hemispheres for producing beads. The cavities are formed beforehand in the sheets of thermoplastic film, for example by thermoforming, before the filling step. This separation is made possible by operating in steps, that is to say in sequences, and not continuously. This mode of operation in sequence makes it possible to preserve a good productivity by manufacturing numerous capsules by sequence. In the approaching step, numerous cavities are joined to receive the filling fluid and held together forming a filling pocket. The filling fluid does not need to be mounted in temperature since the thermoforming of the cavities has already occurred before the introduction of the fluid. We can choose it without this constraint. The fluid may for example be a water-based paint.

The thermoplastic material of the film is chosen for example from polyolefins such as polypropylene or polyethylene. The material may be biodegradable, for example oxobiodegradable. She can incorporating a filler, for example a mineral filler, to make the ball more brittle for use in a striking paintball.

According to an improvement, the panels are from the same film and delimited between two free edges of the film and a central fold along which the film is folded during the approach step. The cavities of the two panels are formed at the same time and their relative positions are perfectly controlled. Folding the film along the central fold, ensures an alignment of the cavities from one pan to another. In addition, the same tools can be used to make the cavities of the two panels.

Advantageously, the pairs of bars are successively tightened from the nearest of the free edges to the nearest of the central fold. The panels are thus allowed to take their position freely during tightening, avoiding the formation of any folds.

According to other characteristics:

the free edge of the ends is guided by a stop to align them during the approach step. If the free edges are well aligned, in combination with the central fold, the cavities are also well aligned.

- Centering pins are inserted into respective holes of the two faces during the approach step to align the sections. This technique in replacement or in addition to the previous one also ensures in particular the relative position in the longitudinal direction of the panels. The holes will have preferably been made in the same step as the cavities to ensure the accuracy of their relative positions with the cavities.

the welding is carried out by heated welding elements which are brought together around the cavities to weld the panels together, the welding elements comprising angled surfaces for pushing the material towards the inside of the cavities. By pushing the material inward, the junction surface between the cavities is enlarged inwards, which in turn allows cutting of the material. capsule flush with the walls while maintaining a junction surface between the cavities.

- Cutting is carried out with a punch to detach the capsules from the sheets of film. This cutting means is very fast to implement and very productive. A blade bypasses the cavity over its entire periphery and pinches the remaining two thicknesses of the panels against a matrix so as to achieve a compact cut,

The invention also relates to a capsule-forming machine containing a fluid, the machine comprising guide means for receiving and guiding two sheets of thermoplastic film each having at least one column of cavities, so as to match the respective cavities of each pan, plating means for clamping the flaps against each other, filling means for supplying the fluid into the cavities, and soldering means for welding the flaps together at the periphery of the cavities , characterized in that the plating means comprise pairs of bars arranged vertically and arranged to tighten successively His sides together along the columns of cavities and form pockets, Its filling means being arranged to fill the fluid pockets.

According to a constructive arrangement, its guide means comprise a pair of upper rollers for bringing the two panels together between the rollers upstream of the bars. Thus, the sections are guided without friction to fit between the bars.

Additionally, the guide means further includes a pair of input rollers and a pair of motorized lower rollers for driving and tensioning the superimposed panels between its pairs of input and bottom rolls. This ensures a traction on the panels for their placement between the bars. This ensures that they are taut and do not form folds. According to other characteristics:

the plating means comprise two press assemblies, each press assembly comprising a support in which the bars are slidably mounted in a direction of work via sliders and on which the welding elements are fixedly mounted, each bar comprising elastic means tending to push the bar in an abutment position towards the other bar of the same pair, mounted on the other support. Thus, the only relative movement of the supports is the shift in action of the pairs of bars. At the end of the stroke of the support, the flanges are gripped between the welding elements.

- The plating means further comprises a pair of horizontal bars at a lower end of the vertical bars to close the bottom pockets, Thus, the fluid filling does not exceed the extent of the bars.

the welding elements comprise pairs of heating rings and stop means for keeping, on at least a part of its periphery, a spacing between the rings. A crown of connection of the capsule to the pan is thus preserved and thus avoids detaching the capsules. Rather than a crown, the connection can also be made by several segments. The manipulation of the sections makes it possible to transfer all the capsules to the next station where the cutting can be done in optimal conditions.

Brief description of the figures

The invention will be better understood and other features and advantages will appear on reading the description which follows, the description referring to the appended drawings among which:

FIG. 1 is a perspective view of a machine of which only the essential elements have been represented; FIG. 2 is a side view of the machine of FIG. 1;

Figure 3 is a front view of the machine of Figure 1;

~ Figures 4 to 7 are sectional views along line IV-IV of Figure 2 at different stages of the manufacturing process seion the invention;

- Figures 8 and 9 are views, respectively in perspective and in section, welding means according to the invention;

FIG. 10 is a view of the detail X of FIG. 9.

DETAILED DESCRIPTION

A capsule forming machine according to the invention is placed downstream of a thermoforming station, not shown, which is intended to make cavities 10 distributed in columns and rows on a film 1 of thermoplastic material, with the following: four columns 14a, 14b, 14c, 14d. The cavities 10 are made for example in sequences, but they could also be carried out continuously. The cavities 10 are distributed symmetrically with respect to an axis A longitudinal longitudinal axis! of the film 1. The columns are parallel to the axis A. In the example shown in Figures 1 to 3, the film 1 arrives to the capsule forming machine to the horizontal, in a direction of movement represented by the arrow F1 parallel to the axis A, the cavities 10 are hemispheres, so as to form capsules in the form of beads by the meeting of two hemispheres.

The capsule forming machine comprises guide means 2 for receiving and guiding the film 1. For this purpose, its guide means comprise, in the direction of travel of the film 1, a pair of input rollers 21, a return roller 22. a pair of upper rollers 23 and a pair of motorized lower rollers 24 for driving and tensioning the film 1 between the pairs of input and lower rollers 21, 24. The input rollers 21 grip the film 1 and provide a resistance the progress of film 1, so as to provoke a tension across the entire length of the film 1 to the lower rollers 24, The opposing resistance may simply come from the rolling resistance, but may later be supplemented by a braking device on the rollers, adjustable or not. The deflection roller 22 can direct the film 1 from the horizontal position to the vertical position, it comprises circular grooves, not shown, provided for the passage of each column of cavities 10 without pressing on them. The upper rollers 23 can bring two sides of the film 1 between the rollers and thus form a central fold 13 which delimit the two sections 1 1, 12 in the longitudinal direction of the film 1 which corresponds to the direction of travel. The sections 1 1, 12 are thus brought together so as to match two free edges 1 10, 120 of the film and the respective cavities 10 of each pan 1 1, 12.

The machine further comprises plating means 3 for clamping the flanges 1 1, 12 against each other, arranged between the upper rollers 23 and its lower rollers 24. The plating means 3 comprise two press assemblies 30. facing each other, on either side of a welding plane at which the sections 1 1, 12 of the film 1 are intended to pass. Each press assembly 30 comprises a support 305, only one of which is shown in FIGS. 1 and 3 for the sake of simplification, in which bars 301a, 301b, 302a, 302b, 303a, 303b, 304a, 304b are mounted vertically. and sliding in a working direction F2 perpendicular to the welding plane via sliders 307, with two sliders per bar. Each support 305 is also slidably mounted in the working direction F2 and is able to be set in motion by actuating means 306, symbolized in FIG. 3 by a jack 306 for one of the supports 305 between a withdrawal position. and a clamping position. The cylinder could be replaced by a crank system or a screw-nut system. In the retracted position, a free space is maintained between the press assemblies 30 for the passage of the film 1. Elastic means constituted by springs 308 are mounted around the cups 307 and tend to push the bars 301a, 301b, 302a, 302b, 303a, 303b, 304a, 304b towards the other press assembly 30 on the support 305, the sliders 307 comprise a stop ring 3070 in order to limit the stroke of the sliders 307 and to determine an abutment position of the bars 301a, 301b, 302a, 302b, 303a, 303b, 304a, 304b, achieved particularly when the press assemblies 30 are in the retracted position.

In the embodiment of the invention, shown in particular in FIGS. 4 to 7, each bar 301a, 302a, 303a, 304a of one of the press assemblies 30 corresponds to another bar 301b, 302b, 303b, 304b of the other press assembly 30 with which it forms a pair of bars 301, 302, 303, 304 capable of pinching the panels 1 1, 12. There are thus three pairs of vertical bars 301, 302, 303 of in order to frame two pairs of cavity columns 10. The press assemblies 30 also include a pair of horizontal bars 304, on the side of the lower rollers 24, extending across the width covered by the pairs of vertical bars 301, 302, 303 and at the end of these. As can be seen in particular in FIG. 4, the stops of each pair of bars 301, 302, 303, 304 are selected so that the abutment position of each pair 301, 302, 303, 304 is progressively shifted. Thus, the abutment position S 1 foremost concerns the first pair of bars 301, the rightmost one in FIG. 4, followed by the second pair 302, which is central, and finally by the third pair 303, which is the leftmost. The pair of horizontal bars 304 is synchronized with the third pair of vertical bars 303.

At least one of the bars of each pair is heated, so as to achieve a weld between the sections when the bars are supported one on one. The second pair of central bars 302 comprises centering means 5 comprising centering pins 50 on one of the bars 302b projecting towards centering housings, not shown, carried by the reciprocal bar 302a to receive the centering pins 50.

Welding means are provided and comprise pairs of welding elements 309 fixedly mounted on the supports 305. Thus, the welding elements 309a, 309b of the same pair 309 come closer when the supports 305 come closer together. Each welding element 309a, 309b comprises a ring 3090 which has a working surface 3091 of annular shape and diagonally oriented towards the inside, as shown in FIG. 10. The welding element 309a, 309b further comprises a sheath 3092 in which is inserted an electrical resistance 3093 adapted to heat the ring 3090. Stop means 31 limiting the stroke of the supports 305 are provided to maintain a spacing between the rings 3090 on their periphery.

The machine further comprises filling means 4 for supplying a fluid into the cavities 10, the filling means 4 being arranged to pour the fluid near the upper end of the pairs of vertical bars 301, 302, 303, to feed each column of cavities 10. The filling means 4 comprise in particular two tubes 40 which open vertically downwards after a horizontal path above the plating means 3. The filling means 4 further comprise a dosing pump, not shown , allowing to deliver the necessary quantity of fluid through its tubes 40.

Operation

It is considered that in the initial position, the film 1 is already in place as shown in the figures, the startup phase not forming part of the invention. Typically, the film 1 is unwound manually at least up to the lower rollers 24 to be pinched and then driven by said rollers. The press assemblies 30 are in the retracted position.

The first step is to move the film 1 by one step by driving it through the lower rollers 24 to put facing press assemblies 30 of the columns 14a, 14b, 14c, 14d of cavities 10 not yet met. The unwinding of the film 1 is stopped and several operations then take place simultaneously.

At a first station, not shown, the film 1 is heated to soften it in view of the step at the next station.

At a second station, not shown, the cavities 10 are formed by thermoforming. For this, the film 1, ramoili the previous post, is for example pinched between two matrices, one of which carries fingerprints. The vacuum is made on the side of the impressions so that the film 1 is deformed and plated in the cavities to form the cavities 10. The temperature of the matrix is such that a cooling of the film 1 is done so that it cures sufficiently to be extracted from the matrix. In the same operation, centering holes 15 are made through the film 1 symmetrically with respect to the central fold.

The next post is the capsule forming machine. In the first step, the film 1 is retained by the input rollers 21 as it is driven by the lower rollers 24 so as to stretch it. The film 1 is oriented downwards by the return roll 22 and is folded in two along the central fold 13 so that two sides 1 1, 12 of the film 1 on either side of the central fold 13 is place in opposite of each other. This approximation is achieved by the upper rollers 23 in combination with the drive voltage. The cavities 10 of the outermost columns 14a, 14d are placed facing each other, while the cavities of the columns 14b, 14c on the side of the central fold 13 are placed facing each other. other, so as to form two pairs of columns of cavities 10.

Then, we continue the step of bringing the two sections 1 1, 12 which matches the respective cavities 10 of each pan 1 1, 12 by bringing together the two press assemblies 30. During the approximation, the bars of the first pair 301 approach each other and come to enclose the two sections 1 1, 12 along the free edges 1 10, 120, opposite the central fold. Then, in the continuation of the movement approaching the press assemblies 30, the bars of the second pair 302, then those of the third pair 303 and the horizontal bars 304 enclose the two sections 1 1, 12 on either side of the pairs of columns of cavities 10. When bringing together the bars of the central pair 302, the centering pegs 50 engage in the respective centering holes 15 of the two panels 1 1, 12 and in the corresponding centering housings, in order to ensure even better the correspondence of the cavities 10 from one pan to another. Pockets are thus delimited between His panels 1 1, 12 and bars, each pocket having a column of cavities 10. A weld is made along the pockets so that subsequently, the fluid contained in the pockets remains in place and does not does not flow even after removal of the bars. The weld can be limited to the outermost pairs of bars, which is sufficient to contain the remaining fluid.

In the next step, the bags are filled with a fluid such as paint or any other material that it is desired to encapsulate. The fluid then completely fills the pockets, and in particular the cavities, descending by gravity. The quantity of fluid can be predetermined and controlled by means of a device for measuring the delivered volume, or slaved to a detection of the level of fluid reached in the pockets.

After filling, the supports 305 are brought closer to the abutment means 31 so that the pairs of welding elements 309 come closer and the welding rings 3090 come into contact with the panels 1 1, 12 for the pinch. The position shown in particular in FIG. 10 is attained and a continuous weld is thus produced at the periphery of the cavities 10 for assembling between them two cavities 10 coming respectively from each pan and thus forming a ball 16 containing the fluid. Under the effect of the nip, the temperature that softens the thermoplastic material and the angled shape of the work surface, a bead 16 of material is formed inwardly, in the extension of the wall of the cavities 10, a space remains between the working surfaces, so as to maintain a connecting ring between the ball and His panels 1 1, 12. As soon as the welding is performed, the press assemblies 30 take over the withdrawal position.

In a last step, not shown, it is proceeded to a die cut to detach the balls 18 of the sections 1 1, 12 of film 1.

The invention is not limited to the embodiment which has just been described by way of example. Capsules of different shape of a sphere and with a junction plane different from a ring can be produced. The upper rollers could be replaced by fixed guides, for example bent sheet. Centering by the centering pins could be replaced or complemented by abutment of the free edges on the same stop along the press assemblies. The welding could be performed by other heating techniques, such as the use of ultrasound, high frequency current, or induction if the film has conductive particles. The stop principle for the welding means could be achieved by a stop of the welding elements of the same pair through the panels or through cuts previously made in the panels, at least one of the welding elements being mounted in an elastic way. The welding elements could abut one against the other so as to obtain the cutting of the capsules directly in this phase, possibly including ejection means to ensure that the capsule does not remain in one of the elements welding. These ejection means may be compressed air injectors in the cavity of the welding elements. It can also be ejectors sliding in the axis of the welding elements. The drive of the film could be achieved not by adhesion to the rollers, but positively, by toothed wheels in cooperation with perforations made in the panels, in the manner of film films. Positioning at the end of the step displacement of the film can be achieved by a position encoder on the drive motor, on one of the rollers, on an independent encoder wheel, or by detecting a mark on the film made for this purpose.

List of references [1] WO2009 / 074732 A1: published on June 18, 2009

Claims

1. Process for manufacturing capsules (16) containing a fluid according to which the following steps are carried out:

- reception of two sections (1 1, 12) of thermoplastic film (1), each section (1 1, 12) comprising at least one column (14a, 14b, 14c, 14d) of cavities (10) formed;

- bringing together the two sides (1 1, 12) to match the respective cavities (10) of each side;

- filling of the cavities (10) with the fluid;

- welding of the sides (1 1, 12) around the cavities (10) to form the capsules (16);

characterized in that we proceed in steps, and in the bringing together step, we plate the sides (1 1, 12) by pairs of bars (301, 302, 303) which successively pinch the sides (1 1, 12) on either side of the pairs of columns of cavities (10), and in the filling step, the pocket delimited between two pairs of bars (301, 302, 303) is filled.

2. Method according to claim 1, according to which the sections (1 1, 12) come from the same film (1) and delimited between two free edges (1 10, 120) of the film (1) and a central fold (13) along which the film (1) is folded during the rapprochement step,

3. Method according to claim 2, according to which the pairs of bars (301, 302, 303) are tightened successively from the closest to the free edges (1 10, 120) towards the closest to the central fold (13).

4. Method according to claim 2, according to which the free edge (1 10, 120) of the sections (1 1, 12) is guided by abutment to align them during the rapprochement step.

5. Method according to claim 1, according to which centering pins (50) are introduced into respective centering holes (15) of the two sides (1 1, 12) during the bringing together step to align its sides (1 1, 12),

6, Method according to claim 1, according to which the welding is carried out by pairs of heated welding elements (309) which are brought together around the cavities (10) to weld the sides (1 1, 12) together, the welding elements comprising rings (3090) which have surfaces (3091) at an angle to push the material towards the interior of the cavities (10).

7. Method according to claim 1, according to which punch cutting is carried out to detach the capsules (18) from the sections (1 1, 12) of film (1).

8, Machine for forming capsules (16) containing a fluid, the machine comprising guide means (2) for receiving and guiding two sections (1 1, 12) of film (1) made of thermoplastic material each comprising at least one column of cavities (10), so as to bring into correspondence the respective cavities (10) of each side, plating means (3) for tightening the sides (1 1, 12) one against the other, means of filling (4) to supply the fluid into the cavities (10), and welding means (309) to weld the sides (1 1, 12) together at the periphery of the cavities (10), characterized in that the means of veneer (3) comprise pairs of bars (301, 302, 303) arranged vertically and arranged to successively clamp the sections (1 1, 12) together along the pairs of columns (14a, 14b, 14c, 14d) of cavities (10) and form pockets, the filling means (4) being arranged to fill its pockets with fluid.

9. Machine according to claim 8, in which the guide means (2) comprise a pair of upper rollers (23) to bring the two sides (1 1, 12) closer together between the rollers upstream of the bars (301, 302, 303 ).

10. Machine according to claim 8, in which the guide means (2) further comprise a pair of input rollers (21) and a pair of lower rollers (24) motorized to drive and tension the panels (1 1 , 12) superimposed between the pairs of input (21) and lower (24) rollers,

1 1. Machine according to claim 8, in which the veneering means (3) comprise two press assemblies (30), each press assembly (30) comprising a support (305) in which the bars (301 a, 301 b , 302a, 302b, 303a, 303b) are mounted sliding in a working direction (F2) via slides (307) and welding elements (309a, 309b) are mounted fixed, each bar (301 a, 301 b, 302a, 302b, 303a, 303b) comprising elastic means (308) tending to push the bar (301 a, 302a, 303a) into an abutment position in the direction of the other bar (301 b, 302b, 303b) of the same pair (301, 302, 303), mounted on the other support (305).

12. Machine according to claim 8, in which the plating means (3) further comprise a pair of horizontal bars (304) at a lower end of the vertical bars (301 a, 301 b, 302a, 302b, 303a, 303b) to close the pockets at the bottom.

13. Machine according to claim 10, in which the welding means (309) comprise pairs of heating rings (3090) and stop means (31) to maintain a spacing between the rings (31) over at least part of the periphery. 3090).