EP2849928A1

EP2849928A1 - Molding device for manufacturing containers via blow-molding or stretch blow-molding

Info

Publication number: EP2849928A1
Application number: EP13725412.4A
Authority: EP
Inventors: Vincent Brachet; Daniel Nguyen Van; Georges FROUIN
Original assignee: Sidel Participations SAS
Current assignee: Sidel Participations SAS
Priority date: 2012-05-15
Filing date: 2013-05-03
Publication date: 2015-03-25
Also published as: FR2990641A1; WO2013171402A1; FR2990641B1

Abstract

The invention relates to a molding device (1) comprising: (i) a mold, including two half-molds (2, 3) pivotably mounted around a common axis (Z) between an open position and a closed position of the mold where both half-molds (2, 3) are joined along a joint plane (P); and (ii) a means for locking the mold in a closed position. The locking means comprises: a bolt (4) pivotably mounted on a first (2) of the half-molds (2, 3), near the free edge (12) of the first half-mold (2), between a locked position and an unlocked position; and a strike plate (5) created in a second half-mold (3), near the free edge (13) of the second half-mold (3), capable of receiving said bolt (4). The device is remarkable in that said strike plate (5) has a concave form, is directed toward the outside of the second half-mold (3), and includes a surface (6) against which said bolt (4) bears when the mold is in the locked position.

Description

MOLDING DEVICE FOR MANUFACTURING BY BLOWING OR STRETCH BLOWING OF CONTAINERS

The present invention generally relates to the field of molding devices for the blow-molding or stretch-blow molding of containers from preforms of heated thermoplastic material.

More particularly, the invention relates to improvements made to those devices comprising at least one mold comprising at least two half-molds movable mutually between an open position in which they are spaced from one another and a position closure in which they are closely coupled against each other by cooperating respective bearing faces defining a joint plane.

According to the document FR 2,646,802, there are known locking means for two half-molds in the closed position which comprise a plurality of coupling fingers supported one above the other, coaxially, by a first half-mold and adapted to be moved parallel to the axis of the mold to engage in a plurality of respective receiving ports supported by the second half-mold.

Such locking means are satisfactory and are nowadays common use in mold molding devices called "wallets".

However, these locking means have several significant disadvantages.

In particular, the embodiment is complex and the operating mechanism of such locking means is slow to implement.

This is why the Applicant subsequently made other locking means of the mold in the closed position, which it describes in particular in the application FR 2 856 334.

According to this embodiment, the mold comprises:

two half-molds, each of the two half-molds being pivotally mounted about a common axis between an open position of the mold where the two half-molds are spaced from one another and a closed position of the mold where the two half-molds are joined along a joint plane,

locking means of the mold in the closed position, the locking means comprising a bolt pivotally mounted on a first of the half-molds, at its free end, and a keeper made in a second half-mold, at its free end, adapted to receive said bolt, said latch having a shape substantially U-shaped, said U-shaped comprising a face against which said bolt bears when the mold is in the closed position.

According to this embodiment, the shape of the U of said striker is oriented towards the outside of the second half-mold and the bolt is mounted at a first end of a movable part mounted on the first half-mold, said moving part. being of sufficient length so that said bolt fits into said striker by surrounding the end of the second half-mold, and bears against said bearing face when the mold is in the closed position.

Such a molding device has the advantage of being simpler to implement than the technical solution described in document FR 2 646 802. Moreover, the mechanism of operation of the locking means is faster than that described in FIG. document FR 2 646 802.

At the origin of the invention, it has been sought to further improve the system described in document FR 2 856 334 to further secure the closure of the mold.

The document FR 2 856 334 already includes technical means that secure the closure of the mold. Indeed, the document mentions the presence of an eccentric pivot axis.

The invention offers an alternative to this technical solution, which allows not to off-center the pivoting axis of the moving part, in order to limit the number of movement of the moving part to lock the mold securely and thus save time in the implementation of the closure system.

To this end, the invention relates to a molding device of the type described in document FR 2 856 334, that is to say a molding device for the blow-molding or stretch-blow molding of containers, said device comprising

a mold comprising two half-molds, each of the two half-molds being mounted to pivot about a common axis between an open position of the mold where the two half-molds are spaced apart; on the other side and a closed position of the mold where the two half-molds are joined along a joint plane,

- Locking means of the mold in the closed position, the locking means comprising a bolt pivotally mounted on a first of the half-molds, near the free edge of the first half-mold, between a locking position and an unlocking position, and a strike made in a second half-mold, near the free edge of the second half-mold, adapted to receive said bolt.

In the unlocked position, the bolt is oriented along a line segment that does not intersect said joint plane, said line segment connecting the pivot point of the bolt on the first half-mold and the end of the bolt. Such a molding device is known from documents EP 1 535 719 and FR 2 863 930.

The invention is remarkable in that said striker having a concave shape, oriented outwardly of the second half-mold, comprising a face against which said bolt rests when the mold is in the locking position.

Thus realized, as the straight segment does not cut the joint plane, there is no inconvenience in introducing a preform into the mold or removing a preform from the mold when the bolt is in the unlocking position, even before the opening or complete closure of the mold.

In addition, the fact that the striker is oriented towards the outside of the half-mold makes it possible not to hinder the introduction or the exit of an object in the mold or out of the mold, such as a preform or a molded container.

Thus, the introduction or removal of an object in the mold can be achieved more quickly.

In addition, this saving time to introduce or remove an object from the mold, adds another time saving. This is the one dedicated to securing the mold, which is done without having to offset or refocus a moving part.

This time saving can be used to increase the rates or it can be attributed to another step of manufacturing a container, such as the step of blowing the container. By increasing the time dedicated to the blowing step, a better quality container is obtained. The molding device according to the invention may also comprise the following features, taken separately or in combination:

the bolt may comprise a bar mounted between first ends of at least two connecting rods, said at least two connecting rods having second ends pivotally mounted on said free edge of the first half-mold at an angle of at least 90 °;

said first half-mold may comprise a system for controlling the pivot of the bolt between said locking position and said unlocking position, said control system comprising at least one rail and at least one roller connected to said bolt;

the face of the strike, against which said bolt bears when the mold is in the locking position, can be oriented at an angle of substantially between 8 and 12 degrees with the joint plane of the two half-molds, and preferably 10 degrees;

the second half-mold may comprise additional locking means of said bolt in said striker;

- The additional locking means may comprise a latch, adapted to engage with said bolt when it is inserted in said latch, and an actuator adapted to engage with said latch to hold it in position;

- The latch can be connected to a second roller which is associated with a second rail, and the latch can be pivotally mounted about an axis parallel to the pivot axis of the half-molds

said actuator may be constrained in at least one catch position with the latch by resilient return means, and said actuator may be pivotally mounted about an axis parallel to the pivot axis of the half-molds;

the mold may comprise a system for deactivating the elastic return means, so as to release the latch.

The invention also relates to an installation for the manufacture of containers by blow molding or stretch blow molding of a preform thermoplastic in a mold, comprising at least one device as defined above.

To be able to be executed, the invention is set forth in a sufficiently clear and complete manner in the following description which is, in addition, accompanied by drawings in which:

Figure 1 illustrates an embodiment of a molding device according to the invention, seen in perspective;

FIG. 1B is a very diagrammatic representation of the sliding device of FIG. 1, equipped with latch means and in accordance with the invention;

Figure 2 shows the molding device of Figure 1 in top view, the molding device being in the open position;

Figure 3 shows the molding device of Figures 1 and 2 in top view, the molding device being in the closed position and the locking means not being fully activated; and FIG. 4 shows the molding device of FIGS. 1, 2 and 3, seen from above, the molding device being in the closed position and the locking means being fully activated. Figure 1 shows a molding device 1 according to an embodiment of the invention.

The molding device 1, intended for the manufacture of containers by blow molding or stretch blow molding, comprises a mold comprising two half-molds 2 and 3.

Each of the half-molds 2 or 3 is pivotally mounted around a common axis Z, between an open position illustrated in FIG. 2, where the two half-molds 2 and 3 are separated from one another, and a closing position illustrated in Figure 4, wherein the two half-molds are contiguous defining a plane P joint.

Conventionally, each half-mold is equipped with an internal molding element 7 which face each other when the mold is in the closed position, each element 7 comprising an impression of an object to be produced. For the sake of clarity of the figures, the elements 7 are not shown in detail because they have no technical impact on the embodiment of the invention.

According to the invention, the molding device 1 also comprises mold locking means for holding the device in the closed position.

The locking means, illustrated in particular in Figure 1, comprise a bolt 4 pivotally mounted about an axis Z1 on the half-mold 2 shown on the left of the figure.

The axis Z1 is parallel to the Z axis around which the half-molds 2 and 3 are pivotally mounted.

More specifically, the bolt 4 comprises a bar 10, cylindrical of circular section, fixed to the ends of three connecting rods 1 1, two of the three connecting rods being located at the ends of the bar 10, the rod 10 passing through the end of the third rod 1 1, located substantially in the middle of the bar 10.

The three connecting rods 1 1 are identical. Their other end (that is to say the end of the connecting rods 1 1 which is not fixed to the bar 10) is pivotally mounted about the axis Z1, near the free edge 12 of the half-mold 2 .

Each of the three links 1 1 defines, between the point of pivot of the bolt 4 on the first half-mold and the end of the bolt 4, that is to say the point of attachment of the bar 10 on the rod 1 1 , a segment 40 on the right.

When the bolt 4 is in the unlocking position, as shown in Figure 2, the segment 40 does not cut the joint plane P.

In particular, the rods January 1 having second ends pivotally mounted on said free edge of the first half-mold at an angle of at least 90 ° (see position of the bolt between Figures 2 and 4), so that the segment 40 is oriented substantially parallel to the joint plane as shown in Figure 2, when the bolt 4 is in the unlocked position. The bolt 4 does not interfere with the introduction of a preform in the mold when it opens. It does not disturb the output of the molded object either.

The locking means also comprise a keeper 5 made in the second half-mold 3 shown on the right in FIG. The striker 5 is formed on the outer part of the half-mold 3, near the free edge 13 of the half-mold 3. The striker 5 extends over the entire height of the half-mold 3. However, in one embodiment alternatively, the strike could extend over part of the height of the half-mold 3.

In addition, the striker 5 has a concave shape, formed in the wall of the mold, having substantially the shape of a V, to accommodate the bar 10 of the bolt 4.

The V-shaped concave striker 5 then has a bearing face 6, that is to say a face 6 against which the bar 10 of the bolt 4 bears when it is inserted into the striker 5 (see schematic representation of FIG. Figure 1B).

To allow the insertion of the bar 10 into the keeper 5, the free edge 13 of the half-mold 3 comprises a notch 14 in which can enter the connecting rod 1 1 of the bolt 4.

Other notches 15 are also provided at the upper and lower ends of the free edge of the half-mold 3 to allow passage to the connecting rods 1 1 end of the bolt 4.

The face 6 of the striker 5, ensuring the support of the bar 10, has the following feature: it is oriented at an angle of 10 degrees (an angle between 08 and 12 degrees).

This is the angle which ensures, on the one hand, a restraint of the bar when the latter is engaged in the keeper 5 and bears against the face 6: Indeed, after closure of the mold, and after commitment of the bar 10 in the striker 5, the bar 10 bears against the face 6, because the mold tends to want to open again when pressurized air is introduced into the mold, during the formation of the molding element. This angle is ideal both to hold the bar 10.

This angle is also ideal for allowing the release of the bar. Indeed, on the other hand, when no more pressure is exerted in the mold, the bar can easily be released thanks to the slope of 10 °.

In accordance with the invention, the molding device 1 comprises additional locking means which will now be described with reference to FIG. 1B and then to FIGS. 2 to 4.

FIG. 1B schematically illustrates the concept of additional locking means: it is a question of securing the position of the bar 10 against the face 6 of the striker 5 surrounding it with a U-shaped element 8, the U-shaped element 8 being rotatably mounted around an axis Z2, parallel to the Z axis or to the Z1 axis.

The bar 6 is then enclosed between the wall of the keeper 5 and the inner face of the U-shaped element 8.

An example of a U-shaped element 8 is shown in FIGS. 2 to 4.

The element 8 is formed by a latch 9, which is in the form of a substantially ovoidal roller, having a first notch 23 in the shape of a U.

The notch 23 is adapted to receive the bolt 4 (and in particular the bar 10 of the bolt 4) so that the latch 9 engages with the bolt 4.

The latch 9 also has, on its outer wall, two second notches 16, which allow engagement with an actuator 17.

To do this, the actuator comprises, on its outer part, an element 18 of complementary shape to that of the second notches 16, to ensure engagement between the latch 9 and the actuator 17.

In the context of this embodiment, the element 18 of the actuator is a shoulder formed in the wall of the latter.

The function of the actuator 17 is to hold the latch 9 in position. It is also pivotally mounted about an axis Z3 parallel to the axis Z around which the two half-molds 2 and 3 pivot.

To do this, the actuator 17 is constrained in at least one setting position with the latch 9 by elastic return means 19 such as a spring.

The device therefore also comprises a system for deactivating the elastic return means, so as to release the latch 9.

To allow the rotational or pivoting movements of the various elements 4, 9 and 17 of the locking mechanism of the invention (that is to say the bolt 4, the latch 9 and the actuator 17), these elements 4, 9 and 17 are connected to rollers movably mounted moving in cams.

To simplify the reading of Figures 2 to 4, only a roller 20 has been shown on these. This is the roller 20 controlling the engagement of the bolt 4 in the waste 5.

FIG. 1 shows a roller 21 for controlling the rotation of the latch 9. The path provided by each of the rollers 20 and 21 makes it possible to impose a rotational movement on the bolt 4 and the latch 9, respectively.

The paths are imposed by cams 30 and 31 which are not shown in all the figures to simplify the reading, but which the skilled person usually knows to place wisely.

In general, the shapes of the curves of the cams depend on where they are positioned on a carousel, on which is mounted at least one molding device.

The molding device supports a preform at a predetermined geographic point around the carousel. When the carousel rotates 360 °; or less, the molding device closes, forms the desired element by molding the preform, opens and releases the formed member by molding.

The changes in the curves of the cams, making it possible to deflect the rollers and thus to create a rotational or pivotal movement of the bolt or the latch, therefore depend on the geographical location where the mold must close or open, to realize each of the steps to form the desired element.

Thanks to the face 6 of the striker having a particular angle (as seen above), the mold can begin to open as soon as the bolt 4 leaves the striker 5, before the bolt returns to its initial position, it is ie the totally unobstructed position illustrated in FIGS. 1 and 2.

Similarly, when closing the mold, the pivoting movement of the bolt 4, so that it fits into the keeper 5, can be initiated before the mold is closed.

Thus, thanks to its design, the molding device according to the invention opens and closes faster than the molding devices of the state of the art. The closing or opening step of the molding device can therefore be performed at a smaller rotation angle of the carousel.

This makes it possible to increase the rates, or even to increase the time devoted to the molding, and in particular the cooling time of the molded elements. For example and concretely, with the current molding devices, the time required between the beginning of the opening of the mold and the end of the closure of the mold, to insert a preform for example, corresponded to a rotation of the carousel 70 ° . With the solution according to the invention, a rotation of the carousel of only 58 degrees is necessary.

Moreover, the cooperation of a bolt of circular section with a face of a striker allows a catch of play during the locking phase. In fact, the bolt of circular section is in contact with the face of the striker along a contact line, and not according to a complementary shape in three dimensions (complementary form of the striker and the bolt in the locking position of the mold), as we usually find. In known solutions where two complementary shapes are associated, it is understood that if there is a game, it is difficult to cooperate the complementary shape of the bolt with that of the keeper intended to accommodate it. The invention does not have this drawback because it supports not two complementary shapes but a straight line and a support face.

It is understood from the foregoing how the invention makes it possible to ensure a secure locking, while allowing a quick opening or closing of the mold, since the movements of the half-molds during the opening and closing can be realized by at the same time as the movements of the locking or unlocking means, which saves time in the molding step of an element, and therefore a significant increase in rates.

It should be understood that the invention is however not limited to the embodiment shown, and that it is the implementation of any equivalent means.

Claims

1. Molding device (1) for the blow-molding or stretch-blow molding of containers, said device (1) comprising

a mold comprising two half-molds (2; 3), each of the two half-molds (2; 3) being pivotally mounted about a common axis (Z) between an open position of the mold where the two half-molds molds (2; 3) are spaced from one another and a closed position of the mold where the two half-molds (2, 3) are joined in a joint plane (P),

- Locking means of the mold in the closed position, the locking means comprising a bolt (4) pivotally mounted on a first (2) of the half-molds (2, 3), near the edge (12) free of the first half mold (2), between a locking position and an unlocking position, and a keeper (5) made in a second half-mold (3), close to the free edge (13) of the second half-mold (3), adapted to receive said bolt (4),

in the unlocking position, the bolt (4) being oriented along a segment (40) on the right which does not intersect said joint plane (P), said segment (40) on the right connecting the point of pivot of the bolt on the first half -mould and the end of the bolt,

characterized in that said striker (5) has a concave shape, oriented towards the outside of the second half-mold (3), comprising a face (6) against which said bolt (4) rests when the mold is in position locking.

2. Device according to claim 1, characterized in that the bolt comprises a bar (10) mounted between first ends of at least two rods (1 1), said at least two connecting rods (1 1) having second ends mounted pivoting on said free edge of the first half mold at an angle of at least 90 °.

3. Molding device according to any one of claims 1 or 2, characterized in that said first half-mold (2) comprises a system of control of the bolt pivot (4) between said locking position and said unlocking position, said control system comprising at least one rail (30) and at least one roller (20) connected to said bolt (4).

4. Molding device according to any one of the preceding claims, characterized in that said face (6) of said striker (5), against which said bolt (4) bears when the mold is in the locking position, is oriented at an angle (a) substantially between 8 and 12 degrees with the plane (P) of the joint of the two half-molds (2, 3), and preferably 10 degrees.

5. Device according to any one of the preceding claims, characterized in that the second half-mold (3) having means (9, 17) for additional locking said bolt (4) in said striker (5).

6. Device according to claim 5, characterized in that the additional locking means comprise a latch (9), adapted to engage with said bolt (4) when it is inserted in said keeper (5), and an actuator ( 17) adapted to engage said latch (9) to hold it in position.

7. Molding device according to claim 6, characterized in that the latch (9) is connected to a second roller (21) which is associated with a second rail (31), and in that the latch (9) is mounted pivoting about an axis (Z2) parallel to the pivot axis (Z) of the half-molds (2, 3).

8. Molding device according to claim 6 or 7, characterized in that said actuator (17) is constrained in at least one setting position with the latch (9) by elastic return means (19), and in that said actuator (17) is pivotally mounted about an axis (Z3) parallel to the pivot axis (Z) of the half-molds (2, 3).

9. Molding device according to claim 8, characterized in that the mold comprises a system for deactivating the elastic return means (19), so as to release the latch (9). Apparatus for the manufacture of containers by blow molding or stretch blow molding of a thermoplastic preform in a mold, comprising at least one device according to any one of the preceding claims.