FR3065388A1 - MOLD EJECTION DEVICE COMPRISING A SLIDING LINK CHAIN CONNECTED BY CONNECTING ELEMENTS - Google Patents

Abstract

The ejection device comprises: - a thrust device (14) movable in translation along a first axis (A1), - at least one ejection element (28) movable in translation along a second axis (A2), different from the first axis (A1), - at least one transfer device (26) connecting the thrust device (14) and the ejection element (28), arranged to move the ejection element (28) according to the second axis (A2) when the thrust device (14) is moved along the first axis (A1). The transfer device (26) comprises at least two links (44) movable in translation relative to each other and with respect to the thrust device (14) and to the ejection element (28), said links (44) being interconnected by at least one connecting element (64) connected to each of said links (44).

Description

Holder (s): FAURECIA INTERIEUR INDUSTRIE Simplified joint-stock company.

Extension request (s)

Agent (s): LAVOIX.

MOLD EJECTION DEVICE COMPRISING A CHAIN OF SLIDING LINKS CONNECTED BY CONNECTING ELEMENTS.

FR 3 065 388 - A1 (5 /) The ejection device includes:

a pushing device (14) movable in translation along a first axis (λ1),

- at least one ejection element (28) movable in translation along a second axis (A2), different from the first axis (A1),

- at least one transfer device (26) connecting the pushing device (14) and the ejection element (28), arranged to move the ejection element (28) along the second axis (A2) when the pushing device (14) is moved along the first axis (A1).

The transfer device (26) comprises at least two links (44), which are movable in translation relative to one another and relative to the pushing device (14) and to the ejection element (28), said links (44) being interconnected by at least one connecting element (64) connected to each of said links (44).

-66s

Ejection device for mold comprising a chain of sliding links connected by connecting elements

The present invention relates to an ejection device of the type for a mold for producing an article molded in a molding cavity intended to allow the ejection of the molded article from said molding cavity, said device comprising:

- a mobile pushing device in translation along a first axis between a retracted position and an ejection position,

at least one movable ejection element in translation along a second axis, different from the first axis, between a retracted position and an ejection position, and

- At least one transfer device connecting the pushing device and the ejection element, said transfer device being arranged to move the ejection element along the second axis between its retracted position and its ejection position when the pushing device is moved along the first axis between its retracted position and its ejection position.

In a mold for producing a molded part, such as an injection mold, the molded part is removed from the mold, for example by means of a gripping tool, when the molding cavity is open. In order to facilitate this removal, provision is made to separate the molded part from the part of the mold on which the molded part rests by means of an ejection device.

Such an ejection device generally comprises an ejection plate, movable in a hollow space in the part of the mold in a direction corresponding to the direction of ejection of the part, and one or more ejection rods integral with the plate ejection and opening into the wall of the part of the mold against which the molded part is applied. By moving the ejection plate in the direction of ejection, the ejection rods push the molded part so as to separate it from the wall of the mold part, which allows subsequent removal of the molded part. The use of several rods is particularly advantageous when the molded part has a large surface because these rods can be distributed over this surface in order to push the part into different parts of it and avoid deformation and or breakage of the part at during its ejection. Using an ejector plate allows all rods to be moved simultaneously using a single ejector plate actuator.

However, in such an ejection device, the rods are movable only in a single ejection direction, which limits the possibilities of ejection strokes. Such a limitation can be problematic for parts having complex shapes, for example when these parts are not planar and have zones extending in one or more planes different from a plane perpendicular to the direction of ejection or when they include elements projecting in a direction different from the ejection direction.

In addition, for parts having complex shapes, such as an undercut part, the simple ejection of the part from the mold does not allow the undercut part to be removed from the mold. To demold this part, it is known to use a movable drawer in the molding cavity between a molding position, in which the drawer defines with the molding cavity the shape of the undercut area, and a retracted position, in which the drawer is removed from the undercut area and allows the part to be ejected from the mold cavity.

The ejection of such a part therefore requires a drawer actuation operation and a part ejection operation, which increases the mold cycle time and makes the mold structure more complex.

One of the aims of the invention is to overcome these drawbacks by proposing an ejection device offering greater freedom of arrangement while being less bulky and also allowing the withdrawal of a drawer from a counter zone. - undercut during the ejection of the part.

To this end, the invention relates to an ejection device of the aforementioned type, in which the transfer device comprises at least two links, movable in translation relative to one another and relative to the pushing device and to the ejection element, said links being interconnected by at least one connecting element connected to each of said links so as to allow the displacement of the links in translation with respect to each other.

The transfer device makes it possible to modify the direction of ejection of the ejection element by choosing a second axis inclined relative to the first axis. Thus, by way of example, the ejection device may comprise an ejection rod ejecting the part along the first axis and another ejection rod forming the ejection element and ejecting the part along the second axis, which allows to eject pieces of complex shape. Furthermore, by providing a molding surface at the end of the ejection element, for example to form an undercut part on the molded article, this molding surface can be disengaged from the undercut part at the during the movement of the second rod between its retracted position and its ejection position. Thus, the actuation of the ejection device also makes it possible to demold part of the molded article.

The connecting element makes it possible to maintain the links together and to prevent them from separating during the translation of one relative to the other, which would cause a malfunction of the transfer device. . In addition, the connecting element makes it possible to form a coherent chain which can be handled in one piece, which facilitates the assembly, disassembly and maintenance of the ejection device.

According to other characteristics of the ejection device according to the invention, taken in isolation or in any technically possible combination:

- The connecting element is formed by a link comprising two opposite ends, said ends each being articulated to one of the links;

- The connecting element is formed by a flexible element connected at each of its ends to one of said links;

- The connecting element comprises a lug at each of its two ends, each lug being introduced into a bore of one of the links so as to mount the movable connecting element in rotation relative to said links;

- The transfer device comprises a guide element receiving said links, said links being moved in a displacement stroke in said guide element by the pushing device and moving the ejection element, said links being guided in said element guidance over the entire travel stroke;

- the links are identical to each other;

- the second axis forms a non-zero angle with the first axis;

each link comprises a first sliding surface forming a translation surface with a first adjacent link and a second sliding surface forming a translation surface with a second adjacent link;

- Each sliding surface forms an angle relative to a direction perpendicular to the first axis, said angle being negative to delay the movement of the ejection element relative to the pushing device or positive to accelerate the movement of the element d ejection with respect to the pushing device or zero to move the ejecting element and the pushing device at the same speed; and

the ejection element comprises a secondary molding surface arranged to form a part of the molding cavity and to mold a part of the molded article, the displacement of the ejection element in the ejection position causing separating the secondary molding surface from the part of the molded article molded by said secondary molding surface.

Other aspects and advantages of the invention will appear on reading the description which follows, given by way of example and made with reference to the appended drawings, in which:

- Fig. 1 is a schematic perspective representation of a first mold part comprising an ejection device according to an embodiment of the invention, said device being in the retracted position,

- Fig. 2 is a schematic sectional representation of the first mold part of FIG. 1,

- Fig. 3 is a schematic sectional representation of the first mold part of FIG. 2, the ejection device being in an intermediate position between the retracted position and the ejection position,

- Fig. 4 is a diagrammatic representation in section of the first mold part of FIG. 2, the ejection device being in the ejection position,

- Fig. 5 is a schematic perspective and exploded representation of the ejection device according to an embodiment of the invention,

- Fig. 6 is a schematic representation of part of the ejection device of FIG. 5, and

- Fig. 7 is a schematic perspective representation of links connected together by connecting elements according to one embodiment of the ejection device according to the invention,

- Figs. 8 and 9 are schematic representations of links linked together by a connecting element according to another embodiment of the ejection device according to the invention in different positions of the links relative to each other,

- Fig. 10 is a schematic perspective representation of links linked together by a connecting element according to another embodiment of the ejection device according to the invention,

- Fig. 11 is a diagrammatic side view of a connecting element capable of connecting links together according to another embodiment of the connecting element, and

- Figs. 12 to 16 are schematic sectional representations of the first mold part, the ejection device being in the retracted position, and showing different displacement strokes of the ejection device.

With reference to FIG. 1, an embodiment 1 of a molded article 2 is described which can have any shape suitable for being molded. Such an embodiment mold 1 is for example an injection mold, a compression mold, a foaming mold or the like. More generally, a mold makes it possible to impart a desired shape to a material placed in a molding cavity having the desired shape.

The molded article 2 is for example a motor vehicle or other part. More particularly, according to the embodiment shown in the figures, the molded article 2 comprises a main surface 4 and an undercut part 6 relative to the main surface 4, that is to say a part comprising at at least one surface which cannot be removed from the mold by simply separating two mold parts and requiring a complementary molding element which can be moved in a direction different from the direction of separation of the two mold parts.

The embodiment mold 1 comprises a first part 8 and a second part (not shown to simplify the figures), movable relative to each other between an open position, in which the first and second parts are spaced apart. on the other, and a closed position, in which the first and second parts are brought closer to each other so as to define a closed main molding cavity. The main molding cavity has a shape complementary to the main surface 4 of the molded article 2 to be produced. The movement from the closed position to the open position takes place in an opening direction D, shown in the figures. The first part comprises a molding surface 10 defining, with a molding surface of the second part, the main molding cavity when the first and second parts are in the closed position.

The main surface 4 is such that it can be separated from the molding surface 10 by a displacement of the molded article 2 in a single ejection direction, for example parallel to the opening direction D. Consequently, the main surface 4 is not necessarily flat and may have any shape allowing demolding by displacement of the molded article 2 in the direction of ejection. Thus, according to the embodiment shown in the figures, the main surface 4 comprises a first part 5 substantially perpendicular to the opening direction D and a second part 7 inclined relative to the first part 5. It should be noted that the main mold cavity could also be arranged to form elements projecting from the main surface 4, for example ribs, as long as these elements can also be separated from the main mold cavity by displacement of the molded article 2 according to the direction of ejection.

According to the embodiment shown in the figures, the main molding cavity is in fluid communication with a secondary molding cavity defined by the molding surface 10 of the first part and a complementary molding surface 12 carried by the ejection device of the invention, as will be described later. The complementary molding cavity has a shape complementary to the undercut part 6 of the molded article. The main mold cavity and the complementary mold cavity together form the mold cavity of the embodiment mold 1.

The embodiment mold 1 is for example an injection mold arranged to inject a plastic material at a predetermined pressure into the molding cavity. To this end, the production mold 1 comprises all the means making it possible to carry out and control this injection and the formation of the part, such as one or more injection nozzles for the plastic material, means for regulating the temperature of the molding cavity, means for actuating and moving the first and second parts of the embodiment mold 1, etc. Since such means are known, they will not be described in more detail here.

The production mold 1 comprises an ejection device arranged to facilitate the removal of the molded article 2 from the production mold 1 after its production. Once the molded article 2 is made, the first and second parts of the mold are moved to the open position. The molded article 2 is then placed against the molding surface 10 of the first part 8, as shown in FIGS. 1 and 2, and the ejection device is arranged to separate the molded article 2 from the molding surface 10, as shown in FIG. 4, in order to allow the gripping of the molded article 2 to take it out of the production mold. It should be noted that the ejection device can be actuated during the opening of the mold 1 so that the ejection of the molded article 2 does not necessarily start while the mold is already in the open position.

The ejection device comprises a pushing device 14 movable in the first part 8 along a first axis A1 between a retracted position, shown in Figs. 1 and 2, and an ejection position, shown in FIG. 4. The first axis A1 extends in the direction of ejection and is for example substantially parallel to the direction of opening D so that, in the ejection position, the molded article 2 is spaced from the molding surface 10 in the space between the first part 8 and the second part of the mold.

The pushing device 14 comprises at least one ejection plate 16 disposed, movably in translation along the first axis A1, in a space 18 of the first part 8. In the retracted position, the ejection plate 16 is disposed in an upstream part 20 of the space 18, that is to say the part of the space 18 furthest from the molding surface 10, and in the ejection position, the ejection plate 16 is disposed in a downstream part 22 of the space 18, that is to say the part of the space 18 closest to the molding surface 10.

The pushing device 14 further comprises an actuating element 24 integral in displacement with the ejection plate 16. The actuating element 24 is connected to a transfer device 26 itself connected to an ejection element 28.

The ejection element 28 is movable along a second axis A2, different from the first axis A1. According to the embodiment shown in the figures, the ejection element 28 is a movable block carrying the complementary molding surface 12. Thus, in the retracted position, the block is arranged in the first part so that the molding surface complementary 12 extends opposite the molding surface 10 of the first part and defines therewith the complementary molding cavity. The ejection element 28 further comprises an actuating end 30. The ejection element 28 further comprises an actuating rod 31 connected, by its downstream end, to the actuating end 30 of the block mobile and extending along the second axis A2. The upstream end of the actuating rod 31 is connected to the transfer device 26, as will be described later. It should be noted that the actuating rod 31 could be made in one piece with the movable block. However, providing a movable block and an actuating rod 31 formed from two separate parts makes it possible to improve the adaptability of the ejection element 28 to different molds, as will be described later.

The second axis A2 forms an angle a with the first axis A1. The value of the angle a is chosen according to the shape of the molded article. More particularly, in the case where the molded article 2 comprises an undercut area 6, the angle a depends on the distance necessary to exit the movable block from the undercut area 6 during the ejection of the molded article 2, as will be described later.

Thus, the ejection element 28 is movable between a retracted position and an ejection position respectively when the pushing device 14 is in the retracted position and in the ejection position by means of the transfer device 26 which is arranged to transform the movement of the pushing device 14 along the first axis A1 into movement of the ejection element 28 along the second axis A2, as will now be described.

The transfer device 26 comprises a guide element 33 extending in the first part 8 of the mold from space 18 to the molding surface 10 along a path extending along the first axis A1 in space 18 and according the second axis A2 in the part of the first mold part 4 extending between the space 18 and the molding surface 10. The guide element 33 comprises a first section 32, for example formed by two first sections 34, extending in space 14 along the first axis A1 and defining, for example between the first two profiles 34, a first groove, or guide slide, 36, as shown in FIG. 5. The guide element 33 also comprises a second section 38, for example formed by two second sections 40, extending in the first part 8 between the space 18 and the molding surface 10 along the second axis A2 and defining , for example between the two second profiles 40, a second groove, or guide guide 42, as shown in FIG. 5. The guide grooves 36, 42 are defined by at least two opposite walls of the sections 34, 40. These opposite walls extend along the first axis A1 for the first section 32 and according to the second A2 for the second section 38, that is to say that the opposite walls extend along the displacement path of the links, as will be described later. The guide element 33 is fixed relative to the first part 8 of the mold.

It should be noted that the ejection plate 16 is movable in translation relative to the first section 32. For this purpose, the ejection plate 16 comprises a cavity 43 arranged to receive the two first sections 34 of the first section 32. This imprint 43 is able to slide around the first section 32, which allows the ejection plate 16 to be moved between its retracted position and its ejection position, as will be described later.

The transfer device 26 further comprises at least two links 44 interconnected and one of which is connected to the thrust device 14 and the other of which is connected to the ejection element 28. The links 44 are movable in translation relative to each other and relative to the pushing device 14 and to the ejection element 28. The translation of the links 44 between them takes place along sliding surfaces 46 and relative to the pushing device 14 and the ejection element 28, the sliding surfaces 46 being substantially parallel with respect to each other. Thus, each link 44 comprises a first sliding surface 46 forming a translation surface with an adjacent first link 44 and a second sliding surface 46 forming a translation surface with a second adjacent link 44. The length of the sliding surfaces 46 is such that the links 44 do not disengage from each other during the movement of the ejection device between its retracted position and its ejection position. In addition, these sliding surfaces 46 are sufficient to be able to transmit the thrust forces from the ejection plate 16 to the ejection element 28.

Each sliding surface 46 forms an angle β with a direction perpendicular to the first axis A1, as shown in FIGS. 11 to 15 The adjustment of the angle β relative to the first axis A1 makes it possible to adjust the advance or the delay of displacement of the ejection element 28 relative to the displacement of the pushing device 14, as will be described later .

The number of links 44 of the transfer device 26 depends on the path followed by the links 44 in the guide element 33 and is arranged so that the links connect the pushing device 14 to the ejection element 28. More particularly, the links 44 connect an actuating link 48 integral with the ejection plate 16 to the upstream end of the actuating rod 31.

The actuation link 48 is formed of first and second sub-links 50 and 52. The first sub-link 50 is secured in translation of the ejection plate 16 and is movable in translation along the first axis A1. The second sub-link 52 is articulated to the first sub-link 50 and comprises a sliding guide surface 46 intended to be connected to a link 44 of the transfer device 26, as shown in FIGS. 5 and 6. The second sub-link 52 is thus movable in rotation relative to the first sub-link 50 around an axis substantially perpendicular to the plane containing the first axis A1 and the second axis A2.

The transfer device 26 may comprise more than two links 44, including two end links connected respectively to the actuation link 48 secured to the ejection plate 16 and to the upstream end of the actuation rod 31, and at least one intermediate link connected to the two end links or several intermediate links successively connected to each other so as to form a chain of links 44 extending in the guide element 30 between the actuating link 48 and the actuating rod 31.

All the links 44 are identical, that is to say that they have an identical shape and structure, whether they are end links or intermediate links.

Several forms of link 44 can be envisaged. However, these shapes are adapted to cooperate with each other and with the guide element 33 over the entire travel of movement of the links 44 so that the links 44 are guided in the guide element 33 over the entire travel of travel.

To this end, each link 44 comprises at least one guide surface 54 arranged to cooperate with the first guide groove 36 and with the second guide groove 42 over the entire travel of movement of the links. By "cooperate" is meant that the guide surface 54 is in sliding, sliding and / or rolling contact with one of the guide grooves 36 and 42 over the entire travel of movement of the link 44 carrying this guide surface 54 Thus, when the link 44 is in the first section 32 of the guide element 33, the guide surface 54 is in contact with at least one surface of the first guide groove 36 and when the link 44 is in the second section 38, the guide surface 54 is in contact with at least one surface of the second guide groove 42. According to the embodiment shown in Figs. 1 to 6, the guide surface 54 is formed by a roller 56 having a diameter substantially equal to the width of the guide grooves 36 and 42. The cylindrical peripheral surface of the roller 56 forms the guide surface 54 while being in contact sliding with the walls of one of the guide grooves 36, 42 at at least two points on the surface. According to the embodiment shown in the figures, each link 44 comprises two rollers 56 arranged to cooperate respectively with one of the sections 34, 40, forming the first section 32 and the second section 38. According to one embodiment, the rollers 56 are also movable in rotation relative to the links, so that the guide surface 54 can also roll on the walls of the guide grooves 36 and 42. Thus, the guidance of the links 44 in the guide element 33 is ensured effectively, which avoids any risk of blocking or entrainment of the ejection device by blocking a link 44 in the guide element 30. It should be noted that the guide surface 54 could be defined directly by the shape of the link 44 without requiring the addition of a roller 56, this shape can be arranged to define a sliding contact with the guide element. According to one embodiment, each link 44 comprises two opposite guide surfaces 54 arranged to be in permanent contact with the opposite walls defining the guide grooves 36, 42 of the guide element 33.

To ensure the translational movement of the links relative to each other, relative to the actuating link 48 secured to the ejection plate 16 and relative to the upstream end of the actuating rod 31, each link 44 comprises two sliding surfaces 46, each formed by a wall of the link 44. The walls forming the sliding surfaces 46 can be arranged in different ways, as will be described by way of example, as long as they are complementary and allow a displacement in translation of each other. According to the embodiment shown in FIGS. 1 to 6, each link 44 has, in a plane containing the first axis A1 and the second axis A2, an S-shaped section, as more particularly visible in FIG. 6. Thus, each link 44 comprises two external branches and an internal branch connected together so as to define two grooves 58, each extending between the internal branch and one of the external branches and opening in two opposite directions. The opposite walls of the outer branches and the inner branch each define a sliding surface 46. Thus, as shown in FIG. 6, each link comprises six sliding surfaces 46a, 46b, 46c, 46d, 46e and 46f defined by the facing walls of each groove 58 and by the external surfaces of the external branches of the link 44. Such an embodiment makes it possible to ensuring a robust connection between the links 44, since each link 44 is held in two grooves 58 of adjacent links 44. In this case, the sub-link of the actuation link 48 and the upstream end of the actuation rod 31 each include a complementary groove for receiving the sliding surface 46 of the end links.

According to the embodiment shown in FIG. 7, each link 44 comprises a groove 60 and a lug 62, the lug 62 being of shape complementary to that of the groove 60. The sliding surfaces 46 are defined by the interior surfaces of the groove 60 and by the exterior surfaces of the lug 62. The groove 60 of a link 44 is thus arranged to receive the lug 62 of an adjacent link 44. Such an embodiment ensures a robust connection between the links 44 and a guide in the sliding of the links 44 relative to each other.

It should be noted that in the figures, the sliding surfaces 46 have been shown as being substantially flat. It is understood, however, that these sliding surfaces could also be curved. In this case, the angle β is formed between a tangent to a sliding surface and a direction perpendicular to the first axis A1.

It should be noted that the sub-link 52 of the actuating link 48 and the upstream end of the actuating rod 31 each has a sliding surface 46 of suitable shape to ensure sliding contact with the sliding surfaces 46 of the links 44 described above. Such an embodiment has the advantage of being compact, especially in a direction perpendicular to the first and second axes A1 and A2.

The sliding between the sliding surfaces 46 and between the links 44 and the guide element 33 can be favored by the materials used to produce the sliding surfaces 46, the guide surfaces 54 and / or the guide grooves 36 and 42 or by coating these surfaces and / or walls or by using a lubricant.

The links 44 are also connected two by two by at least one connecting element 64, as more particularly visible in FIGS. 7 to 10. The connecting element 64 is arranged to maintain the connection between the links 44 when they slide relative to each other in order to avoid the “chain breaks” which could occur if the sliding surfaces 46 of two adjacent links 44 came to no longer be in contact with one another during the movement of the links 44 in the guide element 33. The transfer device 26 comprises for example a plurality of connecting elements 64, each arranged to connect two adjacent links 44 together. In addition, connecting elements 64 may be provided to connect the end links to the actuation link 48 on the one hand and to the upstream end of the actuation rod 31 on the other hand.

According to the embodiment shown in FIG. 7, each connecting element 64 is formed by a rigid link articulated at each of its ends 66 to a link 44 among two successive links 44. The articulation of the connecting element 64 is such that the connecting element 64 is able to rotate with respect to each of the links 44 around an axis of rotation R substantially perpendicular to the plane containing the first axis A1 and the second axis A2 so as to allow the connecting element 64 to follow the movements of the links 44 relative to one another when these move in translation relative to one another, as shown for the two upper links 44 of FIG. 7. The link can have any suitable shape. For example, in FIG. 7, each end 66 has the shape of a fork introduced into a groove formed in the peripheral surface of cylindrical shape of the roller 56. Thus, the roller 56 forms both a guide surface 54 and the means for receiving the connecting element 64, which limits the size of the links 44. In order to facilitate the positioning of the connecting elements 64, provision is made, for example, for first and second adjacent links 44 to be connected to one another by a connecting element 64 extending between two rollers 56 arranged on the same side of the links 44 and that the second link 44 is connected to a third link 44 adjacent by a connecting element 64 extending between the two rollers 56 of these links 44 arranged on the other side of the links 44. Thus, the connecting elements 64 are arranged alternately on one side and on the other of the links 44, which prevents the same roller 56 receiving the extr emitted 66 from two different connecting elements 64.

According to the embodiment shown in FIG. 11, the link has the shape of an S-shaped clip, the ends of which 66 each have a rounded shape to match the shape of the groove defined in the cylindrical wall of the roller 56 so as to ensure a robust connection between two successive links 44. In addition, the connecting element 64 comprises two substantially elastic branches 68 extending the ends 66 (and forming the ends of the S) so as to facilitate the introduction of the ends 66 into the grooves of the rollers 56.

The rigid link is for example made from a single piece of metal, in which case the S-shape of FIG. 11 makes it possible to lighten the connecting element 64. The rigid link could also be made of plastic or other material.

According to the embodiment shown in FIGS. 8 to 10, the connecting element 64 is formed by a flexible, flexible and / or elastic element allowing the connecting element 64 to follow the movements of the links 44 relative to each other in the guide element 33 while maintaining the link of the links 44 between them.

For the sake of simplification, only two links 44 have been shown in FIGS. 8 to 10, these links 44 having a simplified shape of a parallelepiped element whose opposite faces form the sliding surfaces 46. It will be noted in fact that the use of connecting element 64 can make it possible to simplify the shape of the links 44 since the shape of these does not necessarily have to provide a function for holding the links together, this function being fulfilled by the connecting elements 64 and possibly by the guide element 33.

Each connecting element 64 is for example formed by a flexible cord whose ends 66 are each fixed to a link 44. When the links 44 extend opposite one another, for example when they are located in the first section 32 of the guide element 33, the cord is folded up as shown in FIG. 9. When the links 44 are offset from each other due to the sliding of the sliding surfaces 46, for example when the links 44 are located in the second section 38 of the guide element 33, the bead deploys so as to allow the movement of the links 44 relative to one another, as shown in FIG. 8.

The connection between the ends 66 of the connecting element 64 and the links 44 is arranged to allow the displacement of the cord relative to the links 44. Thus, the connection between the ends 66 and the links 44 is for example a free connection in rotation about an axis of rotation perpendicular to the plane containing the first axis A1 and the second axis A2. Such a connection could be obtained by forming a loop at the ends 66 of the cord and by passing this loop around the rollers 56 for example. According to another embodiment shown in FIG. 10, the connecting element 64 comprises at each of its ends 66 a lug 70 extending along the axis of rotation and mounted movable in rotation in a bore provided in the link 44 to which the end 66 is linked. Such an embodiment makes it possible to avoid having to provide a specific fixing element on the links 44, such as a roller as described above. Thus, the structure of the links 44 can be simplified. The cord is for example made in one piece from flexible plastic material, rubber for an elastic cord, or the like. As in the embodiment of FIG. 7, the connecting elements 64 are for example arranged alternately on one side and on the other of the links 44.

According to another embodiment, a single connecting element 64 connects more than two successive links 44 by providing, for example, a plurality of lugs distributed along the cord and each introduced into a bore of the successive links 44. In this case, the bead is elastic in order to allow the connecting element 64 to adapt to the shape of the chain of links 44. Thus, one could provide a single connecting element 64 extending from the link actuation 48 at the upstream end of the actuation rod 31 and connected to each of the links 44 provided between the actuation link 48 and the upstream end of the actuation rod 31.

The ejection device may further comprise one or more ejection rods 72 extending in directions parallel to the first axis A1. One end of the ejection rod 72 is integral with the ejection plate 16 and its other end is flush with the molding surface 10 in the retracted position of the ejection device and forms part of the molding surface 10 , as shown in Figs. 1 and 2. The ejection rod (s) 72 are arranged to allow the ejection of the molded article 2 in the direction of opening of the mold, as will now be described.

The operation of the ejection device described above will now be described.

During the molding of article 2, the mold is in the closed position and the ejection device is in the retracted position, in which the ejection plate 16 is located in the upstream part 20 of the space 18, the rod ejection 64 is flush with the molding surface 10 and in which, according to the embodiment shown in the figures, the ejection element 28 defines with the first part 8 the secondary molding cavity by its secondary molding surface 12.

Once the article has been produced, the mold is opened by spreading the first and second mold parts from one another in the opening direction D. During this opening or after it, the ejection device is actuated to pass from its retracted position to its ejection position.

To do this, the ejection plate 16 is actuated to move in the space 18 towards the downstream part 22 of this space 18, as shown in FIG. 3. During this movement, the ejection plate 16 moves along the first axis A1 by sliding around the first section 32 of the guide element 33, this first section 32 penetrating into the cavity 43 of the ejection plate 16 provided for this purpose.

The displacement of the ejection plate causes the displacement of the ejection rod 72 in a direction parallel to the first axis A1, which separates the molded article 2 from the molding surface 10 in this direction, as shown in FIG . 3.

In addition, the displacement of the ejection plate 16 causes the displacement of the actuation link 48 along the first axis A1 which itself causes the displacement of the links 44 in the guide element 30, the links 44 causing the displacement of the ejection element 28.

As shown in Fig. 1, in the retracted position, the links 44 are initially located in the first section 32 of the guide element 30. The movement of the ejection plate 16 results in a movement along the first axis A1 of the links 44 which gradually engage in the second section 38 and change direction to move along the second axis A2, as shown in FIG. 3. This change of direction is possible by the sliding of the sliding surfaces 46 of the links 44 relative to one another.

The displacement of the links 44 along the second axis A2 causes a displacement along this axis of the actuating rod 31 and the movable block. Due to the angle a between the first axis A1 and the second axis A2, the displacement of the movable block causes the movable block to slide out of the undercut area 6, as shown in FIG. 3, which allows this area to be demolded. It should be noted that by adapting the value of the angle β, it is possible to delay or accelerate the movement of the movable block outside the undercut zone 6 relative to the movement of the pushing device 14. C In other words, for a movement at a given speed of the pushing device along the first axis A1, the movable block will move at a higher speed, in the case of an accelerated movement, or lower, in the case of a delayed movement, at this given speed. The acceleration or the delay of the displacement of the movable block relative to the pushing device 14 makes it possible to synchronize the displacement of the movable block with that of the ejection rod (s) 64 so that the mobile block and the ejection rods 72 reach the ejection position at the same time when the ejection strokes are different.

In Fig. 12, the angle a is substantially equal to 30 ° and the angle β is zero. In this case, the movable block moves at the same speed as the pushing device 14.

In Fig. 13, the angle a is substantially equal to 35 ° and the angle β is substantially equal to -35 °. In this case, the movable block moves at a speed lower than the speed of movement of the pushing device 14.

In Fig. 14, the angle a is substantially equal to 20 ° and the angle is substantially equal to -40 °. In this case, the movable block moves at a speed lower than the speed of movement of the pushing device 14.

In Fig. 15, the angle a is substantially equal to 15 ° and the angle β is substantially equal to 20 °. In this case, the movable block moves at a speed greater than the speed of movement of the pushing device 14.

In Fig. 16, the angle a is substantially equal to 15 ° and the angle β is substantially equal to 30 °. In this case, the movable block moves at a speed greater than the speed of movement of the pushing device 14.

Thus, it is understood that by choosing a negative β angle, the displacement of the movable block is delayed and by choosing a positive β angle, the displacement of the movable block is accelerated.

When the ejection plate reaches its ejection position, in which it is for example in contact with the upper wall of the space 18 of the first part 8, as shown in FIG. 4, the molded article 2 is completely separated from the molding surface 10 and the movable block is completely extracted from the undercut area

6. Thus, the molded article 2 can be removed from the mold without hindrance and without interference with one of the parts of the mold and of the ejection device.

The ejection device described above therefore allows the ejection of molded articles of large dimensions and / or of complex shape without weakening the first part of the mold. In addition, the transfer device can be used to adapt the ejection device to the shape of the molded article 2. The chain of links 44 can be easily modified by adding or removing links 44, which are all identical and interchangeable . In addition, the angle a between the first axis A1 and the second axis A2 can be modified by simply changing an interface piece 74 interposed between the first section 32 and the second section 38. This interface piece 74 allows more or less incline the second section 38 relative to the first section 32. Thus, common elements of the ejection device, such as the links 44, the actuating rod 31, the first and second sections 34 and 40, the plate d ejection 16 and the ejection rod (s) 72 can be used for different molds. It suffices to change only the movable block when the shape of the secondary molding surface 12 must be modified and / or the interface piece 74 when the angle a has to be modified.

The ejection device described above could be modified in various ways while remaining in accordance with the invention. Thus, by way of example, the ejection element 28 may not include a secondary molding surface and serve only for the separation of the molded article 2 from the molding surface 10, in particular when the main surface 4 of the molded article 2 has areas extending in directions different from a direction substantially perpendicular to the direction of opening. The links 44 could also be formed from simple blocks, the external surfaces of which form the sliding and guiding surfaces. In such an embodiment, the links 44 are not directly linked to each other and are in simple sliding contact with one another. compared to others.

In addition, it is understood that the mold could comprise several second ejection elements 28 and several corresponding transfer devices 26 to allow the molding and ejection of several undercut areas 6 and / or the ejection of several areas of complex shape of the main surface 4. In this case, a single ejection plate 16 carrying several actuation links 48 can be provided for simultaneously actuating all the second ejection elements 28.

Claims (10)

1. - Ejection device for a mold for producing a molded article (2) in a molding cavity intended to allow the ejection of the molded article (2) from said molding cavity, said device comprising: - a pushing device (14) movable in translation along a first axis (A1) between a retracted position and an ejection position, - at least one ejection element (28) movable in translation along a second axis (A2), different from the first axis (A1), between a retracted position and an ejection position, - at least one transfer device (26) connecting the pushing device (14) and the ejection element (28), said transfer device (26) being arranged to move the ejection element (28) according to the second axis (A2) between its retracted position and its ejection position when the pushing device (14) is moved along the first axis (A1) between its retracted position and its ejection position, characterized in that the device transfer (26) comprises at least two links (44), movable in translation relative to each other and relative to the thrust device (14) and the ejection element (28), said links (44) being interconnected by at least one connecting element (64) connected to each of said links (44) so as to allow the displacement of the links (44) in translation with respect to each other. 2. - Ejection device according to claim 1, wherein the connecting element (64) is formed by a rod comprising two opposite ends (66), said ends (66) each being articulated to one of the links. 3. - Ejection device according to claim 1, wherein the connecting element (64) is formed by a flexible element connected at each of its ends (66) to one of said links (44). 4. - Ejection device according to any one of claims 1 to 3, wherein the connecting element (64) comprises a lug (70) at each of its two ends (66), each lug (70) being introduced into a bore of one of the links (44) so as to mount the connecting element (64) movable in rotation relative to said links (44). 5. - Ejection device according to any one of claims 1 to 4, wherein the transfer device (26) comprises a guide element (33) receiving said links (44), said links (44) being moved according to a displacement stroke in said guide element (33) by the pushing device (14) and moving the ejection element (28), said links (44) being guided in said guide element (33) over the entire displacement race. 6. - Ejection device according to any one of claims 1 to 5, wherein the links (44) are identical to each other. 7, - Ejection device according to any one of claims 1 to 6, wherein the second axis (A2) forms a non-zero angle (a) with the first axis (A1). 8. An ejection device according to any one of claims 1 to 7, in which each link (44) comprises a first sliding surface (46) forming a translation surface with a first link (44) adjacent and a second sliding surface (46) forming a translation surface with a second adjacent link (44). 9. An ejection device according to claims 7 and 8, in which each sliding surface (46) forms an angle (β) relative to a direction perpendicular to the first axis (A1), said angle (β) being negative. to delay the movement of the ejection element (28) relative to the pushing device (14) or positive to accelerate the movement of the ejection element (28) relative to the pushing device (14) or zero 15 to move the ejection element (28) and the pushing device (14) at the same speed. 10. An ejection device according to any one of claims 1 to 9, in which the ejection element (28) comprises a secondary molding surface (12) arranged to form a part of the molding cavity and for molding part of the molded article (2), moving the ejection member (28) to the ejection position 20 causing the separation of the secondary molding surface (12) from the part of the molded article (2) molded by said secondary molding surface (12).