FR3081747A1 - MOLDING TOOL WITH COMPRESSED GAS-OPERATED HOLDER - Google Patents

Abstract

The molding tool (1) comprises: - a mold movable between an open position and a closed position, - a holding shim (22) of a covering element (6) movable relative to a first mold part ( 8) between a separated position and a holding position, - a device for moving the holding wedge (22) comprising at least one rod (26) movable relative to a body (28), said rod (26) defining with said body (28) a first actuation chamber (30), - a device for controlling the movement device. The displacement device is connected to a source of compressed gas (32), the control device comprising at least a first inlet valve (42) interposed between the first actuation chamber (30) and the source of compressed gas ( 32).

Description

Molding tool comprising a holding shim actuated by compressed gas

The present invention relates to a tool for molding a molded element comprising at least one molded body and at least one coating element extending over at least part of said molded body, the molding tool being of the type comprising:

- a mold comprising a first mold part, comprising a first molding surface, and a second mold part, comprising a second molding surface, the mold being movable between an open position, in which the first mold part and the second mold part are spaced from each other, and a closed position, in which the first molding surface and the second molding surface define therebetween a molding cavity having the shape of the molded element;

- at least one shim for holding the coating element against the first molding surface, said shim being movable relative to the first mold part between a separated position, in which the holding shim is separated from the first molding surface, and a holding position, in which a holding face of the holding wedge extends opposite a part of the first molding surface;

a device for moving the holding wedge between the separated position and the holding position, said displacement device comprising at least one rod secured to the holding wedge and movable relative to a body secured to the first mold part between a separated position, in which the holding wedge is in the separated position, and a holding position, in which the holding wedge is in the holding position, said rod defining with said body at least one first chamber actuation;

- a device for controlling the movement device.

The invention also relates to a method for producing a molded element by means of a molding tool.

Molding tools for obtaining a molded body coated with a coating element in a single molding operation are known. In other words, these molding tools allow the molded body to be overmolded on the covering element. In such molding tools, the coating member is placed and held against a molding wall, then the molding cavity is closed and the molded body is formed on the coating. The covering element is held for example by means of a holding block which must be able to be moved between a holding position, in which it holds the covering element against the molding wall, and a separated position , in which it frees access to the molding wall in order to allow the placement of the covering element against the molding wall and the extraction of the molded element from the molding cavity.

The displacement of the holding wedge is generally obtained by the actuation of a hydraulic cylinder integrated in the molding tool.

However, the presence of such a jack greatly increases the size of the molding tool and requires that it be dimensioned to support the hydraulic pressure necessary to actuate the jack, which also increases the cost of the molding tool. . In addition, the actuation of the actuator requires an actuation device separate from the actuation of the movement of the mold parts, which complicates the use of the molding tool.

One of the aims of the invention is to overcome these drawbacks by proposing a molding tool comprising a holding wedge, the actuation of which can be integrated into the mold in a simplified and less bulky manner.

To this end, the invention relates to a molding tool of the aforementioned type, in which the displacement device is connected to a source of compressed gas, the control device comprising at least a first inlet valve interposed between the first chamber d actuation and the source of compressed gas, said first inlet valve being placed in an open position, in which the first actuation chamber is in fluid communication with the source of compressed gas, when the mold is in the open position and that a coating member is placed against the first molding surface, and being placed in a closed position, when the mold is in the closed position, the compressed gas filling the first actuation chamber when said first inlet valve is in the open position, which results in a displacement of the rod and the holding wedge in the holding position, and the wedge may tends to move to the spread position when said first inlet valve is in the closed position.

The compressed gas actuation reduces the size of the molding tool. In addition, the movement device control device can be easily integrated into the molding tool so that a separate control device is not necessary.

According to other optional characteristics of the molding tool, taken individually or in any technically conceivable combination:

the molding tool comprises a device for handling a coating element, movable relative to the first part of the mold between a separated position, in which the handling device is separated from the first part of the mold, and a position application, in which the handling device places a coating element against the first molding surface when the mold is in the open position, said handling device comprising at least one actuating arm arranged to move the first valve. entered the open position when the handling device is in the application position;

the control device also comprises at least a first outlet valve interposed between the first actuation chamber and an atmosphere external to the molding tool, said first outlet valve being in the closed position to prevent fluid communication between the first actuation chamber and the external atmosphere when the first inlet valve is in the open position, and being in the open position, in which the first actuation chamber is in fluid communication with the external atmosphere, when the mold is in the closed position, the pressure in the first actuation chamber being placed at atmospheric pressure when the first outlet valve is in the open position.

- The second mold part is arranged to move the first outlet valve in the open position when the mold is in the closed position;

- The displacement device further comprises a constraint element constraining the rod towards the separated position against the force exerted by the compressed gas in the first actuation chamber;

- the rod defines with the body a second actuation chamber connected to the source of compressed gas, the control device comprising a second inlet valve interposed between the second actuation chamber and the source of compressed gas, said second valve inlet being placed in an open position, in which the second actuation chamber is in fluid communication with the source of compressed gas, when the mold is in the closed position, and being placed in a closed position, when the mold is in the open position or moves between the open position and the closed position, the compressed gas placing the second actuation chamber under pressure when said second inlet valve is in the open position, which causes the shim to move. maintenance in the separated position when the mold moves from the closed position to the open position;

the control device also comprises at least one second outlet valve interposed between the second actuation chamber and an atmosphere external to the molding tool, said second outlet valve being in the closed position to prevent fluid communication between the second actuation chamber and the external atmosphere when the second inlet valve is in the open position, and being in the open position, in which the second actuation chamber is in fluid communication with the exterior atmosphere, when the first valve inlet valve is in the open position, the compressed gas from the second actuation chamber being discharged from said second actuation chamber when the second outlet valve is in the open position;

- The rod causes a displacement in translation of the holding wedge between the separated position and the holding position; and

- The rod causes the holding wedge to move in rotation between the separated position and the holding position.

The invention also relates to a method for producing a molded element comprising at least one molded body and at least one coating element extending over at least part of said molded body by means of a molding tool as described below. above, the method comprising the following steps:

- place the mold in the open position, the holding block being in the separated position;

- Place a coating element against the first molding surface and the first inlet valve in the open position, which results in a displacement of the holding wedge towards the holding position, in which the holding face of the wedge holding holds the coating member against the first molding surface;

place the mold in the closed position and make the molded body in the molding cavity between the first molding surface and the second molding surface, the covering element being interposed between at least part of the first molding surface and the molded body;

- place the mold in the open position and the holding shim in the separated position and remove the molded element from the molding tool.

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 sectional representation of a part of a molding tool according to a first embodiment of the invention, during an initial stage of the production method according to the invention,

- Fig. 2 is a schematic sectional representation of the part of the molding tool in FIG. 1, during a later stage of the production process,

- Fig. 3 is a schematic sectional representation of a molding tool according to the first embodiment of the invention, during another subsequent step of the production process,

- Fig. 4 is a schematic sectional representation of the molding tool of FIG. 3, during another subsequent stage of the production process,

- Figs 5 to 8 are schematic sectional representations of a molding tool according to a second embodiment of the invention, during different stages of the production process, and

- Figs 9 to 12 are schematic sectional representations of a molding tool according to a third embodiment of the invention, during different stages of the production process.

With reference to the figures, there is described a tool 1 for molding a molded element 2 comprising at least one molded body 4 and at least one coating element 6 extending over at least part of the molded body 4, as shown in the Figs 3, 4,

7, 8, 11 and 12. The molded body 4 is for example produced by injecting a molding material on the coating element 6 and can have any desired shape. The molded body 4 is for example made of flexible plastic material, such as foam, or rigid. The covering element 6 is for example formed by a decorative film, a skin made of plastic or natural material, such as leather, textile or the like. Alternatively, the covering element can also be a functional element, such as a metal part (for example a screw), a screen, a capacitive film, an airbag net or a decorative element such as a logo or whatever.

The molded element 2 for example forms a trim element having for example the shape of a vehicle part that the trim element is intended to garnish. Any shape can be envisaged, in particular three-dimensional shapes including hollow, protruding areas, etc. The covering element 6 comprises at least one part extending around the periphery of the molded body 4. According to one embodiment, the covering element 6 extends over the entire surface of the molded body 4.

The molding tool comprises a mold comprising a first mold part

8, comprising a first molding surface 10, and a second mold part 12, comprising a second molding surface 14. The first mold part 8 and the second mold part 12 are movable relative to each other between an open position, in which the first and second mold parts 8, 12 are spaced from one another so as to leave access to the first and second molding surfaces 10, 14, and a closed position, in which the first and second mold parts 8, 12 are pressed against each other so that the first and second molding surfaces 10, 14 form between them a closed molding cavity having the shape of the molded element 2 to achieve. The movement between the open position and the closed position takes place in a closing direction, represented by the arrow F in FIGS. 3, 7 and 11. The movement between the closed position and the open position takes place in an opening direction, represented by the arrow F ’in Figs. 4, 8 and 12, opposite the closing direction. The molding tool 1 is also equipped with means for injecting (not shown) a molding material into the molding cavity and optionally heating and / or cooling means (not shown) of the molding cavity.

The molding tool 1 further comprises a handling device 16, shown in Figs. 1,2, 5 and 6, arranged to allow the positioning of the covering element 6 against the first molding surface 10 of the first mold part 8. The handling device 16 comprises, for this purpose, a support 18 d a covering element 6, for example carried by a robotic arm 20. The handling device 16 is movable relative to the first mold part 8 between a separated position, in which the handling device 16 is moved away from the first part of mold 8 and in which it is for example arranged to pick up a coating element 6, and an application position, in which the handling device 16 places the coating element 6 against the first molding surface 10 when the mold 1 is in the open position. The coating element 6 is applied against the first molding surface 10 by bringing the support 18 carrying the coating element 6 closer to the first molding surface 10 when the mold is in the open position, as shown by the arrow f in Figs. 1 and 5. When the covering element 6 is applied against the first molding surface 10 as shown in Figs. 2 and 6, a retaining wedge 22 is arranged to hold the covering element 6 against the first molding surface 10, as will be described later, which makes it possible to move the positioning device 16 towards its separated position while leaving the covering element 6 on the first molding surface 10.

The position of the coating element 6 on the first molding surface 10 depends on the position that the coating element 6 must have on the molded element 2 to be produced. According to the embodiment shown in the figures, the covering element 6 covers the entire first molding surface 10, but it is understood that according to other embodiments, the covering element 6 covers only a part of the first molding surface 10. It is also understood that several coating elements 6 can be placed on the first molding surface 10 when the molded body 4 must be coated with several coating elements 6. In this case, a single or several handling devices 16 can be provided for placing the covering elements 6 on the first molding surface 10. As many holding shims 22 as there are covering elements 6 are then provided. In the following description, for reasons of simplicity, a single holding shim 22 and its operation will be described, the other holding shims and their operation being, where appropriate, similar to what will now be described.

The retaining wedge 22 is provided on the first mold part 8 and extends between the first mold part 8 and the second mold part 12 outside the mold cavity or at the periphery thereof. The retaining wedge 22 comprises a retaining face 24 of the covering element 6 facing the first molding surface 10 of the first mold part 8. The retaining face 24 defines a shoulder arranged to form a retaining rim d an edge of the covering element 6 when the latter is placed against the first molding surface 10.

The holding wedge 22 is movable relative to the first mold part 8 between a holding position (Figs. 2, 3, 6, 7, 10, 11), in which the holding wedge 22, more particularly the shoulder formed by the retaining face 24, extends opposite a part of the first molding surface 10, and a separated position (Figs. 1, 4, 5, 8, 9 and 12), in which the shim holding 22, more particularly the shoulder formed by the holding face 24, is spaced from the first molding surface 10 and allows access thereto without interference with the holding wedge. Thus, by position apart, it is meant that the shoulder formed by the holding face 24 does not extend opposite the first molding surface 10 in the directions of opening and closing of the mold 1. In the holding position , the retaining wedge 22 therefore makes it possible to hold the covering element 6 against the first molding surface 10, while in the separated position, the retaining wedge 22 allows the positioning of the covering element 6 on the first surface molding 10 and the removal of a finished molded element from this first molding surface 10 without the holding wedge forming an obstacle to these operations.

The displacement of the holding block 22 between the holding position and the separated position is obtained by a displacement device. According to the embodiments shown in Figs. 1 to 8, the movement of the holding wedge 22 between the holding position and the separated position is a movement in translation in a direction D inclined with respect to the opening and closing directions. According to the embodiment shown in FIGS. 9 to 12, the movement of the holding block 22 between the holding position and the separated position is a movement in rotation around an axis A substantially perpendicular to the directions of opening and closing.

The displacement device according to the embodiments of Figs. 1 to 8 will now be described.

The displacement device comprises a rod 26 secured to the holding shim 22 and movable in translation in the direction D relative to the first mold part 8. As indicated above, the direction D is inclined relative to the directions of opening and closure, that is to say that the direction D forms a non-zero angle with these directions. According to one embodiment, the angle formed by direction D with the opening and closing directions is substantially between 5 and 15 °. It should be noted that the angle and / or the distance of the shim of the first mold part in the separated position can be adjusted, in particular to adapt to the thickness of the covering element 6. The direction D and the displacement in translation of the rod 26 are such that, in the holding position, the holding wedge 22 is applied against the first mold part 8 and that, in the separated position, the holding wedge 22 is separated from the first mold part 8 in the opening direction F 'and is spaced from the first molding surface 10 in a direction substantially perpendicular to the opening direction.

The rod 26 is movable in a body 28 integral with the first mold part 10 and defines with this body 28 at least a first actuation chamber 30 connected to a source of compressed gas 32. The source of compressed gas is for example a source of compressed air, that is to say of air maintained at a pressure higher than atmospheric pressure. The first actuation chamber 30 is closed by a piston 34, formed by an end portion of the rod 26, in sealed contact with an internal wall of the body 28. Thus, when the first actuation chamber 30 is in fluid communication with the source of compressed gas 32, the first actuation chamber 30 is filled with compressed gas which tends to move the piston 34 to increase the volume of the first actuation chamber 30. The arrangement of the rod 26 and of the body 28 is such that the increase in the volume of the first actuation chamber 30 moves the rod 26 and the holding wedge 22 towards the holding position, as shown in FIGS. 2 and 6.

According to the first embodiment, shown in Figs. 1 to 4, the displacement device further comprises a constraint element 36 constraining the rod 26, and therefore the retaining wedge 22, towards the separated position, that is to say against the force exerted by the compressed gas on the piston 34. The constraint element 36 is for example formed by a spring extending in the rod 26 and bearing against a foot 38 secured to the body 28, the rod 26 being slidably mounted on the foot 38 The spring is compressed when the rod 26 and the holding shim 22 are in the holding position and exerts a force on the rod 26 to move it towards the separated position, in which the spring is relaxed.

The first actuation chamber 30 is connected to the source of compressed gas 32 by a first gas circulation circuit 40 extending in the first mold part 8 and inside which a first inlet valve 42, d a device for controlling the displacement device is arranged so as to be interposed between the first actuation chamber 30 and the source of compressed gas 32. The first inlet valve 42 can be actuated between an open position (Figs. 2 , 3), in which it allows fluid communication between the source of compressed gas 32 and the first actuation chamber 30 so that the compressed gas circulates in the first circulation circuit 40 of the source of compressed gas 32 and fills the first actuation chamber 30, and a closed position (Figs. 1 and 4), in which it interrupts the fluid communication between the source of compressed gas 32 and the first actuation chamber 30.

The first actuation chamber 30 is further connected to the atmosphere by a second gas circulation circuit 44 extending in the first mold part 8 and inside which a first outlet valve 46 is arranged so to be interposed between the first actuation chamber 30 and the atmosphere. The first outlet valve 46 can be actuated between an open position (Fig. 3), in which it allows fluid communication between the first actuation chamber 30 and the atmosphere, and a closed position (Figs. 1, 2 and 4 ), in which it interrupts the fluid communication between the first actuation chamber 30 and the atmosphere.

According to one embodiment, the actuation of the first inlet valve 42 between its closed position and its open position is done by an actuating arm 48 provided on the handling device 16 and arranged to move the first valve inlet 42 in its open position when the handling device 16 is in its application position, as shown in FIG. 2. According to one embodiment, the actuation of the first inlet valve 42 takes place while the handling device 16 is already in its application position and the actuation arm 48 undergoes an additional movement to actuate the first inlet valve 42. This can be obtained by providing that the robotic arm 20 can move relative to the support 18 when the handling device 16 is in its application position. This additional movement is made, for example, against a constraint force applied between the support 18 and the robot arm 20 by a constraint element 50, as shown in Figs. 1 and 2. It is thus ensured that the actuation of the first inlet valve 42 takes place while the coating element 6 is already applied against the first molding surface 10.

The first inlet valve 42 further comprises a constraint element arranged to constrain the first inlet valve 42 to its closed position so that the first inlet valve 42 is placed in its closed position when it is not not activated.

According to one embodiment, the actuation of the first outlet valve 46 between its closed position and its open position is done by the second mold part 12 when it is in contact with the first mold part 8 when the mold is in its closed position, as shown in FIG. 3.

The first outlet valve 46 further comprises a constraint element arranged to constrain the first outlet valve 46 to its closed position so that the first outlet valve 46 moves to its closed position when it is not actuated.

As a variant of an actuation of the first inlet 42 and outlet 46 valves by the actuating device 16 and by the second mold part 12, it is understood that this actuation can be done by external control means, by example of the electrical control means. However, such external control means need to be synchronized with the control means for the movement of the mold 1 and of the actuating device 16 while the actuation by the actuating device 16 and by the second mold part 12 simplifies the control device, as will now be described.

A method of producing a molded element 2 comprising a molded body 4 and a coating element 6 by means of a molding tool 1 according to the first embodiment will now be described with reference to Figs. 1 to 4.

As shown in Fig. 1, the mold is initially in the open position, the holding shim 22 in its separated position under the effect of the constraining element 36 and the first inlet 42 and outlet 46 valves in their closed position. The handling device 16 picks up a coating element 6 and moves towards the first molding surface 10, as shown by the arrow f in FIG. 1.

When the handling device 16 arrives in its application position, the covering element 6 is applied and positioned on the first molding surface 10, as shown in FIG. 2. An additional movement of the robotic arm 20 towards the first mold part 8 allows the actuating arm 48 to actuate the first inlet valve 22 to position it in its open position so as to place the first actuating chamber 30 in fluid communication with the source of compressed gas 32 via the first circulation circuit 40. The compressed gas is thus transmitted to the first actuation chamber 30 which is filled by moving the piston 34 as shown by the arrows f 'of Fig. 2. The displacement of the piston 34 results in a displacement of the rod 26 and therefore of the holding wedge 22 in the holding position, as shown in FIG. 2. In this position, the covering element 6 is held against the first molding surface 10 and the handling tool 16 can be moved to its separated position leaving the covering element 6 against the first molding surface 10 Removal of the handling device 16 causes the first inlet valve 42 to move to its closed position. As the first outlet valve is also in its closed position, the pressure of the compressed gas is maintained inside the first actuation chamber 30, which keeps the holding wedge 22 in its holding position.

Once the holding device 16 is moved to its separated position, the mold is moved to its closed position, as shown in FIG. 3. The second part of the mold 12 is therefore applied against the first part of the mold 8. It will be noted that the second part of the mold 12 comprises a housing 50 receiving the holding shim 22 and maintaining the latter in its holding position when the mold is in the closed position, as shown in FIG. 3. In the closed position, the second mold part 12 places the first outlet valve 46 in its open position so that the first actuation chamber 30 is placed in fluid communication with the atmosphere, as shown by the arrow f ”of Fig. 3. Thus, the pressure inside the actuation chamber 30 is released and becomes equal to atmospheric pressure. As the mold is in its closed position, the holding wedge remains in its holding position, however, under the effect of the housing 50 in which the holding wedge 22 is received. Note that the second mold part 12 is also shaped so as not to actuate the first inlet valve 40 in the closed position of the mold. To this end, the second mold part 12 comprises, for example, a hollow zone 51 extending opposite the first inlet valve 40 so that the latter is not actuated when the mold is closed, as shown in the Fig. 3.

In the closed position, the first and second molding surfaces 10, 14 define between them the molding cavity and the molded body 4 can be formed in this cavity on the covering element 6, that is to say that the 'coating element 6 is interposed between at least a portion of the first molding surface 10 and the molded body 4. The production of the molded body 4 is done for example by injection of a molding material into the molding cavity.

When the molded body 4 is produced, the covering element 6 is secured thereto and the mold is moved to its open position, as shown in FIG. 4. During this movement, the second mold part 12 separates from the first mold part 8, which places the first outlet valve 46 in its closed position and which results in a displacement of the rod 26 and of the retaining wedge 22 towards the separated position under the effect of the constraint element 36, as shown in FIG. 4. The molded element 4 can then be removed from the mold without interference with the retaining wedge 22 and the molding tool 1 can be used to make a new molded element 4.

The production method described above is particularly simple to implement and requires only the actuation of the movement of the mold and that of the holding device 16. The molding tool 1 has a reduced bulk and is less costly to produce.

The molding tool 1 according to the second embodiment shown in Figs. 5 to 8 will now be described.

The molding tool 1 according to this embodiment is substantially identical to that of the first embodiment with the exception of the constraint element 36 which is not present in the second embodiment. Only the differences of the molding tool according to the second embodiment compared to that according to the first embodiment will therefore be described below.

Instead of this constraint element, the displacement of the rod 26 and of the holding shim 22 towards the separated position is controlled by a second inlet valve 52 of the control device interposed between the source of compressed gas 32 and a second actuation chamber 54 extending between the piston 34 and the body 28 opposite the first actuation chamber 30. In other words, the piston 34 separates the interior volume of the body 28 into two isolated chambers l 'from each other hermetically by the piston 34, namely the first actuation chamber 30 and the second actuation chamber 54. When the volume of the first actuation chamber 30 increases to move the holding wedge 22 towards the holding position, the volume of the second actuation chamber 54 decreases. Conversely, when the volume of the second actuation chamber 54 increases in order to move the retaining wedge 22 towards the separated position, as will be described later, the volume of the first actuation chamber 30 decreases.

The second inlet valve 52 is placed in a third compressed gas circulation circuit 56 extending between the source of tablet gas 32 and the second actuation chamber 54. The second inlet valve 52 is of the same type that the first inlet valve 40, that is to say that it is actuable between an open position, in which it puts in fluid communication the source of compressed gas 32 with the second actuation chamber 54, and a closed position in which it interrupts the fluid communication between the source of compressed gas 32 and the second actuation chamber 54. In addition, the second inlet valve 52 is also forced towards its closed position. The actuation of the second inlet valve 52 from its closed position to its open position is done in the same way and at the same time as the actuation of the first outlet valve 46. Thus, according to one embodiment, the actuation of the second inlet valve 52 from its closed position to its open position is effected by the second mold part 12, as shown in FIG. 7. In this case, it is advantageous to have the second inlet valve 52 in the vicinity of the first outlet valve 46 so that a single actuation zone of the second mold part 12 simultaneously actuates the first outlet valve 46 and the second inlet valve 52.

The control device further comprises a second outlet valve 58 extending in a fourth circulation circuit 60 of compressed gas and interposed between the second actuation chamber 54 and the external atmosphere of the molding tool 1. The second outlet valve 58 is of the same type as the first outlet valve 46, that is to say that it can be actuated between an open position, in which it places the second actuation chamber 54 in fluid communication with the exterior atmosphere, and a closed position, in which it interrupts the fluid communication between the second actuation chamber 54 and the exterior atmosphere. In addition, the second outlet valve 58 is also constrained to its closed position. The actuation of the second outlet valve 58 from its closed position to its open position is done in the same way and at the same time as the actuation of the first inlet valve 40. Thus, according to one embodiment, the actuation of the second outlet valve 58 from its closed position to its open position is effected by an actuating arm 62 of the handling device 16, as shown in FIG. 6. In this case, it is advantageous to have the second outlet valve 58 in the vicinity of the first inlet valve 40 in order to simplify the structure of the handling device 16 so that it simultaneously actuates the first inlet valve 40 and the second outlet valve 58. As a variant, the actuating arm 48 which actuates the first inlet valve 40 is dimensioned to simultaneously actuate the second outlet valve 58. Similarly, the second mold part 12 is shaped to do not operate the second outlet valve 58 when the mold is in the closed position. When the second outlet valve 58 is adjacent to the first inlet valve 40, it is sufficient to dimension the recessed area 51 adequately so that the second outlet valve 58 is not actuated by the second mold part 12 of the same way as the first inlet valve 40, as shown in FIG. 7.

A method of producing a molded element 2 comprising a molded body 4 and a coating element 6 by means of a molding tool 1 according to the second embodiment will now be described with reference to Figs. 5 to 8.

As shown in Fig. 5, the mold is initially in the open position, the holding shim 22 in its separated position, the first inlet 42 and outlet 46 valves and the second inlet 52 and outlet 58 valves in their closed position. The handling device 16 picks up a coating element 6 and moves towards the first molding surface 10, as shown by the arrow f in FIG. 5.

When the handling device 16 arrives in its application position, the covering element 6 is applied and positioned on the first molding surface 10, as shown in FIG. 6. An additional movement of the robotic arm 20 towards the first mold part 8 allows the actuating arm 48 to actuate the first inlet valve 22 and the actuating arm 62 (or if necessary the single arm actuator 48) actuate the second outlet valve 58 to position them in their open position so as to place the first actuation chamber 30 in fluid communication with the source of compressed gas 32 via the first circuit circulation 40 and the second actuation chamber 54 in fluid communication with the atmosphere via the fourth circulation circuit 60. The compressed gas is thus transmitted to the first actuation chamber 30 which is filled by moving the piston 34 as shown by the arrows f 'in FIG. 6. The second actuation chamber 54 does not oppose this movement since the air present in this second actuation chamber 54 is evacuated to the outside atmosphere, as represented by the arrow f ’” in FIG. 6. The displacement of the piston 34 results in a displacement of the rod 26 and therefore of the holding wedge 22 in the holding position, as shown in FIG. 6. In this position, the covering element 6 is held against the first molding surface 10 and the handling tool 16 can be moved to its separated position leaving the covering element 6 against the first molding surface 10 The withdrawal of the handling device 16 causes the first inlet valve 42 and the second outlet valve 58 to move into their closed position. As the first outlet valve and the second inlet valve 52 are also in their closed position, the pressure of the compressed gas is maintained inside the first actuation chamber 30, which keeps the holding shim 22 in its holding position.

Once the holding device 16 is moved to its separated position, the mold is moved to its closed position, as shown in FIG. 7. The second mold part 12 is therefore applied against the first mold part 8 and maintains the holding shim 22 in its holding position thanks to the housing 50. In the closed position, the second mold part 12 places the first outlet valve 46 and the second inlet valve 52 in their open position so that the first actuation chamber 30 is placed in fluid communication with the atmosphere, as represented by the arrow f ”and that the second actuation 54 is placed in fluid communication with the source of compressed gas 32 via the third circulation circuit 56 as shown by the solid line in FIG. 7. Thus, the pressure inside the first actuation chamber 30 is released and becomes equal to atmospheric pressure, while the second actuation chamber 54 is pressurized. As the mold is in its closed position, the holding wedge remains in its holding position, however, under the effect of the housing 50 in which the holding wedge 22 is received.

In the closed position, the first and second molding surfaces 10, 14 define between them the molding cavity and the molded body 4 can be formed in this cavity on the covering element 6, that is to say that the 'coating element 6 is interposed between at least a portion of the first molding surface 10 and the molded body 4. The production of the molded body 4 is for example by injection of a molding material into the mold cavity.

When the molded body 4 is produced, the covering element 6 is secured thereto and the mold is moved to its open position, as shown in FIG. 8.

During this movement, the second mold part 12 separates from the first mold part 8, which places the first outlet valve 46 and the second inlet valve 52 in their closed position and which causes a displacement of the rod 26 and of the retaining wedge 22 towards the separated position under the effect of the pressure exerted in the second actuation chamber 54 which displaces the piston 34, as shown in FIG. 8. The molded element 4 can then be removed from the mold without interference with the retaining wedge 22 and the molding tool 1 can be used to make a new molded element 4.

The second embodiment described above makes it possible to dispense with a constraint element in the body 28 of the displacement device, which simplifies the structure of the latter and makes it possible to reduce its bulk.

The molding tool 1 according to the third embodiment shown in Figs. 9 to 12 will now be described.

The molding tool 1 according to this embodiment is substantially identical to that of the first embodiment with the exception of the displacement of the retaining wedge 22 which is done in rotation and not in translation. Only the differences of the molding tool according to the third embodiment compared to that according to the first embodiment will therefore be described below.

In this third embodiment, the retaining wedge 22 is articulated on the first mold part 10 around a pivot link 64 allowing rotation of the retaining wedge 22 about an axis of rotation A substantially perpendicular to the directions d opening and closing of the mold. The rod 26 is connected to the holding wedge by a pivot link 66 allowing rotation of the holding wedge 22 relative to the rod 26 about an axis of rotation parallel to the axis of rotation A. A displacement in translation of the rod 26 thus causes a rotational movement about the axis of rotation A of the holding wedge 22 between its separated and holding positions, as shown by the arrows D and D 'of Figs. 10 and 12. A displacement in rotation of the holding shim 22 makes it possible to reduce the size of the molding tool 1, in particular in the open position, since it is not necessary to provide a spacing between the first part of mold 8 and the second part of mold 10 taking account of the displacement stroke of the holding wedge 22 in translation between the holding and spaced positions, as is the case in the first and second embodiments described above.

Note that Figs. 9 to 12, the actuation of the displacement device is shown as being done from the outside of the mold. It is however understood that the structure of the control device described for the first embodiment can also be applied in the third embodiment, that is to say by using first inlet and outlet valves actuated by the handling tool and through the second mold part. It will also be noted that in Figs. 9 to 12, the rod 26 has been shown as a constraint towards the position separated by a constraint element 36, as in the first embodiment. It is however understood that the structure of the control device described for the second embodiment can also be applied in the third embodiment, that is to say by using second actuated inlet and outlet valves. by the second mold part and by the actuation device for moving the holding block in the separated position in place of the constraint element 36. Thus, the third embodiment is compatible with the control devices of the first and second embodiments described above by simply adapting the structure of the first mold part 10.

The method for producing a molded element is substantially identical to what has been described above with reference to the first embodiment or to the second embodiment and will not be described again in detail here. It will simply be noted that during this process, the holding shim 22 moves in rotation between its holding and spaced positions and not in translation. In the case of an external actuation of the displacement of the rod, as shown in Figs. 9 to 12, this actuation must simply be synchronized with the movements of the handling device and of the mold to place the first actuation chamber 30 in fluid communication with the source of compressed gas 32 or with the external atmosphere to move the rod 26 and the holding block 22 between the separated and holding positions, as described above.

Claims (11)

1.- Molding tool (1) of a molded element (2) comprising at least one molded body (4) and at least one coating element (6) extending over at least part of said molded body (4) , the molding tool comprising: - a mold comprising a first mold part (8), comprising a first molding surface (10), and a second mold part (12), comprising a second molding surface (14), the mold being movable between a position open, in which the first mold part (8) and the second mold part (12) are spaced from each other, and a closed position, in which the first molding surface (10) and the second surface molding (12) define between them a molding cavity having the shape of the molded element (2), - at least one retaining wedge (22) of the covering element (6) against the first molding surface (10), said retaining wedge (22) being movable relative to the first mold part (8) between a separated position, in which the retaining wedge (22) is separated from the first molding surface (10), and a retaining position, in which a retaining face (24) of the retaining wedge (22) extends opposite part of the first molding surface (10), - a device for moving the holding block (22) between the separated position and the holding position, said moving device comprising at least one rod (26) integral with the holding block (22) and movable relative to a body (28) integral with the first mold part (10) between a separated position, in which the retaining wedge (22) is in the separated position, and a retaining position, in which the retaining wedge (22) is in the holding position, said rod (26) defining with said body (28) at least one first actuation chamber (30), - a device for controlling the movement device, characterized in that the movement device is connected to a source of compressed gas (32), the control device comprising at least a first inlet valve (42) interposed between the first actuation chamber (30) and the source of compressed gas (32), said first inlet valve (42) being placed in an open position, in which the first actuation chamber (30) is in fluid communication with the compressed gas source (32), when the mold is in the open position and a covering member (6) is placed against the first molding surface (10), and being placed in a closed position, when the mold is in the closed position, the compressed gas filling the first actuation chamber (30) when said first inlet valve (42) is in the open position, which causes displacement of the rod (26) and of the shimholding (22) in the holding position, and the holding shim tending to move towards the separated position when said first inlet valve (42) is in the closed position. 2, - molding tool according to claim 1, further comprising a handling device (16) of a coating element (6), movable relative to the first mold part (8) between a spaced position, in which the handling device (16) is moved away from the first mold part (10), and an application position, in which the handling device (16) places a covering element (6) against the first molding surface ( 10) when the mold is in the open position, said handling device (16) comprising at least one actuating arm (48) arranged to move the first inlet valve (42) in the open position when the handling device (16) is in the application position. 3. - molding tool according to claim 1 or 2, wherein the control device further comprises at least a first outlet valve (46) interposed between the first actuation chamber (30) and an atmosphere outside the molding tool, said first outlet valve (46) being in the closed position to prevent fluid communication between the first actuation chamber (30) and the outside atmosphere when the first inlet valve (46) is in the open position , and being in the open position, in which the first actuation chamber (30) is in fluid communication with the external atmosphere, when the mold is in the closed position, the pressure in the first actuation chamber (30) being placed at atmospheric pressure when the first outlet valve is in the open position. 4, - molding tool according to claim 3, wherein the second mold part (12) is arranged to move the first outlet valve (46) in the open position when the mold is in the closed position. 5. - molding tool according to any one of claims 1 to 4, in which the displacement device further comprises a constraint element (36) constraining the rod (26) towards the separated position against the force. exerted by the compressed gas in the first actuation chamber (30). 6. - molding tool according to any one of claims 1 to 4, in which the rod (26) defines with the body (28) a second actuation chamber (54) connected to the source of compressed gas (32) , the control device comprising a second inlet valve (52) interposed between the second actuation chamber (54) and the source of compressed gas (32), said second inlet valve (52) being placed in a position open, in which the second actuation chamber (54) is in fluid communication with the source of compressed gas (32), when the mold is in the closed position, and being placed in a closed position, when the mold is in the open position or moves between the open position and the closed position, the compressed gas placing the second actuation chamber (54) under pressure when said second inlet valve (52) is in the open position, which causes displacement hold in the spread position when the mold moves from the closed position to the open position. 7. - molding tool according to claim 6, wherein the control device further comprises at least one second outlet valve (58) interposed between the second actuation chamber (54) and an atmosphere external to the tool. molding, said second outlet valve (58) being in the closed position to prevent fluid communication between the second actuation chamber (54) and the external atmosphere when the second inlet valve (52) is in the open position, and being in the open position, in which the second actuation chamber (54) is in fluid communication with the external atmosphere, when the first inlet valve (42) is in the open position, the compressed gas from the second actuation (54) being discharged from said second actuation chamber (54) when the second outlet valve (58) is in the open position. 8. - Molding tool according to any one of claims 1 to 7, wherein the rod (26) causes a displacement in translation of the holding wedge (22) between the separated position and the holding position. 9. - Molding tool according to any one of claims 1 to 7, wherein the rod (26) causes a rotation movement of the holding wedge (22) between the separated position and the holding position. 10.- Method for producing a molded element (2) comprising at least one molded body (4) and at least one coating element (6) extending over at least part of said molded body (4) by means of a molding tool (1) according to any one of claims 1 to 9, said production method comprising the following steps: 5 - place the mold in the open position, the holding shim (22) being in the separated position, - placing a covering element (6) against the first molding surface (10) and the first inlet valve in the open position, which causes a displacement of the holding wedge (22) towards the holding position, in which the holding face 10 (24) of the retaining wedge (22) holds the covering element (6) against the first molding surface (10), - place the mold in the closed position and make the molded body (4) in the molding cavity between the first molding surface (10) and the second molding surface (14), the covering element (6) being interposed between at least part of the 15 first molding surface (10) and the molded body (4), - place the mold in the open position and the holding shim (22) in the separated position and remove the molded element (2) from the molding tool (1).