FR3037849A1 - EJECTION DEVICE FOR A TOOL FOR MAKING A FORMED PART - Google Patents

Abstract

The ejection device (8) comprises: - a main ejection element (10) movable in translation in an ejection direction (E) between a retracted position and an ejection position, - a secondary ejection element (18) movable in translation in an actuating direction (A) between a retracted position and an ejection position; - a transmission element (20) arranged to transmit the movement of the main ejection element (10) to the secondary ejection element (18). The transmission element (20) is movable in translation in a transmission direction (T), the secondary ejection element (18) being mounted in translation on the transmission element (20) in a first direction ( D1), the transmission element (20) being mounted in translation relative to the main ejection element (10) in a second direction (D2).

Description

The present invention relates to an ejection device for a tool for producing a formed part, said device comprising: a main ejection element movable in translation according to a ejection direction between a retracted position and an ejection position, - a secondary ejection element movable in translation in an actuating direction, different from the ejection direction, between a retracted position and an ejection position a transmission element arranged to transmit the movement of the main ejection element to the secondary ejection element. The invention also relates to a tool for producing a formed element comprising such an ejection device. Such an embodiment tool is, for example, an injection mold in which a molded part can be produced by injecting a molding material into a mold cavity having the shape of the part to be produced. The ejection device makes it possible to separate the molded part from the molding cavity in order to make this part accessible to remove it from the mold. Such a part comprises for example an undercut area made by a molding portion which must be released from the area against undercut during demolding of the molded part. The direction of movement of the molding portion out of the undercut area is different from the ejection direction in which the ejection device moves the molded part to separate it from the mold cavity. The direction of movement of the molding part may for example be perpendicular to the direction of ejection.

The ejection device is thus arranged to synchronously move the molding part out of the undercut area while the molded part is moved away from the molding cavity. To be effective, the ejection element must have a proper stroke to move the part a sufficient distance from the mold wall to allow it to be pulled out of the mold and to generate a sufficient stroke to pull the molding part out of the mold. the area undercut. This has the effect of requiring a very large ejection couse which increases the thickness of the mold. This may lead to having to use a higher jig injection press for the operation of the mold. One of the aims of the invention is to overcome this drawback by proposing an ejection device whose ejection element has a sufficient stroke to allow the withdrawal of the formed part and to release the molding part out of the mold. the area against undercut while having a reduced footprint in thickness. For this purpose, the invention relates to an ejection device of the aforementioned type, in which the transmission element is movable in translation in a transmission direction, different from the ejection direction and the actuation direction, the secondary ejection element being mounted movable in translation on the transmission element in a first direction, the transmission element being mounted in translation relative to the main ejection element in a second direction, the first and second directions being arranged so that the displacement of the main ejection element 10 in the ejection direction causes a displacement of the transmission element in the direction of transmission, which causes a displacement of the earth element. secondary in the direction of actuation. Providing a transmission element between the main ejection element, arranged to move the molded part away from the molding cavity, and the secondary ejection element, arranged to move a mold part of a counter zone. stripping out of this zone, the thickness of the part of the mold in which the ejection device is housed can be reduced because the displacement stroke of the ejection element in the direction of ejection does not need to be as important as when the displacement of the secondary ejection element is not controlled by such a transmission element.

According to other features of the ejection device according to the invention: the first direction and the second direction are arranged so that the secondary ejection element moves in a substantially oblique direction of actuation relative to the direction of ejection, - the actuating direction forms an angle substantially between 20 ° and 40 ° 25 with the ejection direction, - the first direction and the second direction each form an angle substantially between 10 ° and 20 ° with the ejection direction, - the transmission direction is substantially perpendicular to the ejection direction, - the transmission element comprises a first cam path extending in the first direction and a second cam path s' extending in the second direction, the secondary ejection element comprising a first follower movable in translation on the first cam path and the main ejection element comprising a second follower movably mounted in translation on the second cam path, each cam path comprises at least one groove and each follower comprises at least one roller movable in translation in said groove, the ejection device secondary comprises a molding part of an undercut area of the formed part, the actuating direction being arranged to move said molding part out of said undercut area during the displacement of the secondary ejection device of the retracted position at the ejection position. The invention also relates to a tool for producing a shaped part of the type comprising a first part and a second part each comprising a forming wall, the first and second parts being movable in translation relative to one another according to a direction of movement between an open position in which the first and second parts are spaced from each other and a closed position in which the first and second parts define between them a cavity having the shape of the workpiece to be formed, said tool further comprising an ejection device as described above, the main ejection element and the secondary ejection element being movable relative to the first part of the tool between the retracted position, in which the main ejection element extends completely into the first part of the tool and a molding part of the ejection element is applied against the forming wall of the first part, and the ejection position, in which at least a part of the main ejection element protrudes from the first part towards the second part, and the molding part of the secondary ejection element is moved away from the forming wall of the first part. According to another characteristic of the embodiment tool according to the invention, the ejection direction is substantially parallel to the opening direction. Other aspects and advantages of the invention will appear on reading the description which follows, given by way of example and with reference to the appended drawings, in which: FIG. 1 is a schematic representation in section of a first part of an embodiment tool and comprising an ejection device according to the invention, the main ejection element and the secondary ejection element are in the retracted position, FIG. 2 is a schematic sectional representation of the first part of FIG. 1, the main ejection element and the secondary ejection element being in the ejection position, FIG. 3 is a diagrammatic representation in section of the ejection device of FIGS. 1 and 2, the main ejection element and the secondary ejection element being in the retracted position, FIG. 4 is a schematic representation in section of a part of the ejection device along the axis IV-IV of FIG. 3, and 3037849 4 - FIG. 5 is a diagrammatic sectional representation of the ejection device of FIG. 3, the main ejection element and the secondary ejection element being in the ejection position. With reference to FIG. 1, there is described a tool 1 for producing a formed part 35 comprising at least one undercut area 4. Such an embodiment tool 1 is for example an injection mold for producing a molded part, such as a vehicle part or the like, or a compression mold for forming such a part by compression, or the like. The production tool comprises a first part 2 and a second part (not shown), each comprising a forming wall 6 arranged facing the forming wall of the other part. The first part 2 and the second part are movable relative to each other in translation in a direction of displacement D, between an open position and a closed position. In the open position, the first part 2 and the second part are spaced from each other so as to leave an accessible space 15 between the forming walls 6. In the closed position, the first part 2 and the second part are close to one another so that the forming walls 6 define between them a cavity having the shape of the part to be produced. The undercut area 4 is such that it can not be defined only by the forming walls 6 so that a molding portion 7 is provided between the forming walls 6 to define with the molding wall 6 of the first part 2, the shape of the undercut area 4, as shown in FIG. 1. In the case of an injection mold, the cavity is for example hermetically closed and in fluid communication with a source of injection material. The cavity can be opened in other production tools. In a compression tool, the forming wall 6 of one of the parts may have a shape substantially complementary to the forming wall of the other part. The production tool 1 further comprises an ejection device 8 comprising a main ejection element 10 arranged in the first part 2 and movable relative thereto between a retracted position, represented in FIGS. 1 and 3, and an ejection position, shown in Figs. 2 and 5. The main ejection element 10 comprises for example one or more ejection rods 12 integral with an ejection plate 14 movable in translation, between the retracted position and the ejection position, in one direction. ejection E, which is for example substantially parallel to the direction of displacement D of the embodiment tool. The ejection plate 14 is for example housed inside the first part 2 which comprises a recess 16 dimensioned to allow the displacement in translation of the ejection element 10 between its retracted position and its position. 'ejection. In retracted position, the main ejection element 10, and more particularly the ejection rod or rods 12, extends for example completely inside the first part 2 and the free end of the rods 12, opposite. at the plate 14, is flush with the forming wall 6 of the first part 2. In the ejection position, the main ejection element 10 is moved so that the ejection rod or rods 12 protrude from the forming wall 6 of the first part 2, between the first part 2 and the second part 4 in the open position, as shown in FIG. 2. Thus, in the ejection position, the free end of the rod or rods 12 extend at a distance h from the forming wall 6 of the first part 2, this distance h corresponding to the stroke traveled by the main ejection element 10 between the retracted position and the ejection position. In known manner, this distance h is arranged to allow easy removal of the formed part 3 after its completion out of the production tool. The displacement of the main ejection element 10 is conventionally controlled by actuation of the ejection plate 14. The ejection device 8 comprises, in addition to the ejection element 10, an element of secondary ejection 18 and a transmission element 20. The secondary ejection element 18 is arranged to move the molding part 7 out of the undercut area 4, as shown in Fig. 2. For this purpose, the secondary ejection element comprises a rod 22 disposed on the ejection plate 14 and passing through the first part 2 to the forming wall 6 of the first part 2. The end of the rod 22 extending to the level of the forming wall 6 carries the molding portion 7. The rod 22 is mounted to move in translation relative to the first part 2 in an actuating direction A, different from the ejection direction E. The element 25 secondary ejection 18 is movable in the direction of ac A between a retracted position (Figs. 1 and 3), in which the molding portion 7 of the secondary ejection element 18 is brought closer to the forming wall 6 of the first part 2 so as to define therewith the shape of the zone in opposition. 4, and an ejection position (Figs 2 and 5), wherein the molding portion 7 is spaced apart from the forming wall 6 in the direction of ejection. Furthermore, in the ejection position, the molding part 7 is also moved in an extraction direction of the undercut area 4. The actuating direction A is the result of the ejection direction E and the extraction direction. The actuating direction A is thus substantially oblique with respect to the ejection direction E. For this purpose, the angle formed between the actuating direction A and the ejection direction E is for example substantially between 20 ° and 40 °. According to one embodiment, the anglea is substantially equal to 30 °.

The secondary ejection element 18 further comprises a connecting element 26 integral with the end of the rod 22 which extends in the recess 16, that is to say the end of the rod. 22 opposite the end bearing the molding portion 7. The joining element 26 is movable in translation with the rod 22 in the actuating direction A.

The joining element 26 is for example fixed to the rod 22 by a screw 27. The joining element 26 forms a first follower of a cam system, as will be described later, and is connected to the element transmission 20, which will now be described. The transmission element 20 is formed by a part joining the main ejection element 10 to the secondary ejection element 18 and arranged to convert the movement of the main ejection element 10 in the direction of the ejection element. ejection E in one movement of the secondary ejection element 18 in the direction of actuation A. The transmission element 20 is housed in the recess 16 of the first part 1 and movable in this recess 16 in translation according to a transmission direction T, different from the ejection direction E and the direction of operation A. The transmission direction T is for example substantially perpendicular to the ejection direction E. The transmission element comprises a first path cam 28 receiving in translation the first follower formed by the junction element 26 and a second cam path 30 receiving in translation a second follower of the main ejection element 10, more particularly formed by the ejection plate 14. The first cam path 28 extends in a first direction D1 and the second cam path 30 extends in a second direction D2, different from the first direction D1. More particularly, the first direction D1 and the second direction D2 are divergent in the direction of ejection E in the direction from the retracted position to the ejection position, i.e. the first direction D1 and the second direction D2 deviate from each other in the direction from the retracted position to the ejection position, as shown in Figs. 3 and 5. According to one embodiment, the first direction D1 and the second direction D2 are symmetrical with respect to the direction of ejection. According to one embodiment, the angle formed between the first direction D1 and the ejection direction E and the angle formed between the second direction D2 and the ejection direction E are substantially between 10 ° and 20 °. °, the anglep and the angle 8 being equal when the first direction D1 and the second direction D2 are symmetrical with respect to the direction of ejection E. The cam paths 28 and 30 are for example each formed by a groove 32 As shown in FIG. 4, each follower respectively formed by the connecting member 26 and the ejection plate 14 in the form of a roller 34 sliding in the groove 32. According to the embodiment shown in FIG. 4, each cam path comprises two grooves 32 extending on opposite sides of the transmission element 20 and receiving a pair of rollers 34 respectively provided on the joining element 26 and on the ejection plate 14. In this case, the pair of rollers 34 of the joining element 26 is formed by the ends of a jaw 36 enclosing the transmission element 20 and provided at one end of the joining element 26 and the pair of rollers. 34 of the ejection plate 14 is formed by the ends of a jaw 38 enclosing the transmission member 20 and provided in the ejection plate 14. Each cam path 28 and 30 includes a first end 40 and a second one. second end 42 and extends substantially rectilinearly between these ends in the direction of the cam path. The first ends 40 are the farthest ends of the forming wall 6 of the first part 2 in the direction of ejection E and they are located next to each other in the direction of transmission T, as more particularly visible in Figs. 3 and 5. The second ends 42 are the closest ends of the forming wall 6 of the first part 2 in the direction of ejection E and they are distant from each other in the direction of transmission T as more particularly visible in FIGS. 3 and 5. Thus, the cam tracks 28 and 30 define a V-shape whose branches extend towards the forming wall 6 of the first part 2 of the embodiment tool 1. The opening angle w of the V 20 is equal to the sum of the angles 13 and S. According to the embodiment shown in the figures, the transmission element 20 is disposed in a through opening 44 of the ejection plate 14, the dimensions of which are arranged to permit movement in the transmission direction T of the transmission element 20 and the connecting element 26. Such an arrangement makes it possible to reduce the bulk of the ejection device in the first part 2 of the tool according to the transmission direction T. In fact, such an arrangement makes it possible not to have to provide an additional space next to the ejection plate 14 in the transmission direction T to allow the displacement of the transmission element 20.

The operation of the ejection device 8 described above will now be described. When the production tool 1 has been used to make a part, the production tool 1 is moved to its open position in order to extract the finished part. Prior to opening the production tool, the ejection device 8 is retracted, i.e., the main ejection element 10 and the secondary ejection element 18 are in the position. retracted, as shown in Figs. 1 and 3 ... In this position, the rollers 34 of the main and secondary ejector elements are in the first ends 40 of the corresponding cam paths 28 and 30. In this position, the rod or shanks 12 of the ejection element 10 are in their retracted position and therefore do not extend projecting from the forming wall 6 of the first part 2 and the molding part 7 is in its retracted position, in which it defines the shape of the undercut area 4 of the molded part 3. Once the production tool is in the open position or during the opening of the production tool, the ejection phase of the formed part is started. To do this, the control device of the main ejection element 10, which is for example synchronized or confused with the control device of the production tool, triggers the displacement of the ejection plate 14 to move the main ejection element 10 from its retracted position to its ejection position, shown in Figs. 2 and 5. The main ejection element 10 moves in the direction of ejection E so as to approach the forming wall 6 of the first part 2 of the tool. Thus, the rod or rods 12 of the ejection element 10 are moved in the ejection direction E so as to exit the forming wall 6 of the first part until reaching the ejection position as shown. in FIG. 2. The displacement of the ejection plate 14 causes the displacement of its roller 34 according to the second cam path 30, that is to say a displacement in translation of the roller 34 in the groove 32 of the second cam path 30 according to the second direction D2. This has the effect of "pulling" on the transmission element 20 which moves in translation in the through opening 44 in the transmission direction T. The displacement of the transmission element 20 in the transmission direction T causes a displacement of the roller 34 of the connecting element 26 according to the first camming path 28, that is to say a displacement in translation of the roller 34 in the groove 32 of the first cam path 28 in the first direction D1. This displacement causes a translational movement of the secondary ejection element 18 in the direction of actuation A, the joining element 26 then approaching the forming wall 6 of the first part 2. This displacement causes a displacement of the molding portion 7 such that the molding portion 7 deviates from the forming wall 6 and at the same time exits the undercut area 4, as shown in FIG. 2. The transition from the ejection position to the retracted position is by a kinematic inverse to that described above. The V-shaped arrangement of the cam paths 28 and 30 makes it possible to reduce the travel of the ejection plate 14 required to move the ejection element 10 between the retracted position and the ejection position while moving. the mold part 7 out of the undercut area 4. Thanks to the invention, for a stroke of the main ejection element 10 allowing an ejection height h, that is to say an equal stroke of the ejection plate in the recess 16 equal to h, the molding part 7 moves in the direction of transmission T out of the undercut area 4 by a distance substantially equal to half the ejection height h, which allows to completely extract the molding portion 7 of the undercut area 4, as shown in FIG. 2. In the absence of transmission element as described above, that is to say with a direct actuation of the displacement of the secondary ejection element by the excrement plate, the displacement of the part of molding 7 out of the undercut area is substantially equal to one third of the ejection height, which requires increasing the stroke of the ejection plate in the recess to allow a total withdrawal of the part of molding 7 of the undercut area 4 and thus to have a recess thickness, measured in the direction of ejection E, higher. Thus, the invention makes it possible to reduce the thickness of the first portion 2 of the tool 1 by reducing the necessary travel of the ejection plate 14 and thus the thickness of the recess 16. Thus, the tool embodiment, and in particular its first part 2 housing the ejection device 8 can be made more compact while maintaining a sufficient stroke to allow removal of the formed element.

Claims (10)

CLAIMS1.- Ejection device (8) for a tool (1) for producing a formed part (3), said device comprising: - a main ejection element (10) movable in translation in an ejection direction (E) between a retracted position and an ejection position, - a secondary ejection element (18) movable in translation in an actuating direction (A), different from the ejection direction (E), between a retracted position and an ejection position; - a transmission element (20) arranged to transmit the movement of the main ejection element (10) to the secondary ejection element (18), characterized in that transmission element (20) is movable in translation in a transmission direction (T), different from the ejection direction (E) and the actuation direction (A), the secondary ejection element (18) ) being mounted mobile in translation on the transmission element (20) according to a first direction (D1), the transmission element (20) being movably mounted in translation relative to the main ejection element (10) in a second direction (D2), the first and second directions (D1, D2) being arranged so that the displacement of the main ejection element (10) in the ejection direction (E) causes the transmission element (20) to move in the transmission direction (T), which causes a displacement of the secondary excrement element (18) in the direction of actuation (A). 2.- ejection device according to claim 1, wherein the first direction (D1) and the second direction (D2) are arranged so that the secondary ejection element (18) moves in a direction of actuation (A) substantially oblique with respect to the ejection direction (E). 3.- ejection device according to claim 2, wherein the actuating direction (A) forms an angle (a) substantially between 20 ° and 40 ° with the ejection direction (E). 4.- ejection device according to claim 2 or 3, wherein the first direction (D1) and the second direction (D2) each form an angle ((3, 8) substantially between 10 ° and 20 ° with the direction of ejectin (E) 3037849 11 5.- ejection device according to any one of claims 1 to 4, wherein the transmission direction (T) is substantially perpendicular to the direction of ejection (E). 5 6. An ejection device according to any one of claims 1 to 5, wherein the transmission element (20) comprises a first cam path (28) extending in the first direction (D1) and a second cam path (30) extending in the second direction (D2), the secondary ejection element (18) comprising a first follower movable in translation on the first cam path (28) and the element main ejection (10) comprising a second follower movable in translation on the second cam path (30). 7.- ejection device according to claim 6, wherein each cam path (28,30) comprises at least one groove (32) and each follower comprises at least 15 a roller (34) movable in translation in said groove ( 32). 8. An ejection device according to any one of claims 1 to 7, wherein the secondary ejection device (18) comprises a molding part (7) of an undercut area (4) of the formed part (3), the actuating direction (A) being arranged to move said molding part (7) out of said undercut area (4) during the displacement of the secondary ejection device (18) of the retracted position at the ejection position. 9. A tool for producing a formed part comprising a first part (2) and a second part each comprising a forming wall (6), the first and second parts being movable in translation relative to one another. other in a direction of movement (D) between an open position in which the first and second parts (2) are spaced from each other and a closed position in which the forming walls (6) first and second parts (2) define between them a cavity having the shape of the workpiece to be formed, said tool further comprising an ejection device (8) according to any one of claims 1 to 8, main ejection element (10) and the secondary ejection element (18) being movable relative to the first part (2) of the tool between the retracted position, wherein the main ejection element (10) ) extends completely into the first part (2) of the and a molding part (7) of the secondary ejection element (18) is brought closer to the forming wall (6) of the first part (2), and the ejection position, in which at least A part of the ejection element (10) projects from the first part (2) towards the second part (4) and the molding part (7) from the ejection element secondary (18) is spaced from the forming wall (6) of the first part (2). 5 10. The production tool according to claim 9, wherein the ejection direction (E) is substantially parallel to the opening direction (D).