FR3072591B1 - MOLD FOR MANUFACTURING RIBBED PIECE AND CORRESPONDING METHOD - Google Patents

Abstract

The mold (1) comprises first and second half-molds (21, 23), first and second internal surfaces (27, 29) of the first and second half-molds (21, 23) being respectively provided to form the front faces and rear (5, 7) of the ribbed piece (3); the second half-mold (23) has a main part (31) and an ejector (33), the ejector (33) having a body (34) having an end surface (35) defining part of the second internal surface ( 29) and a side surface (37) provided to form one side of the rib (9) of the part (3); the ejector (33) comprises a slide (47) movable relative to the body (34) between an extended position in which a first end (49) of the slide (47) projects relative to the side surface (37), and a retracted position in which the first end (49) of the slide (47) is retracted into the body (34).

Description

The invention relates generally to the manufacture by molding of ribbed pieces.

More specifically, the invention is in a first aspect on a mold for manufacturing a ribbed piece, the ribbed piece comprising a front face, a rear face and a rib formed on the rear face.

Such parts may for example be manufactured in a mold of which one of the two half-molds comprises a movable ejector. The ejector has a side surface provided to form one side of the rib, the other side of the rib being formed by an inner surface of the half-mold.

The workpiece is generally ejected by moving the ejector relative to the main part of the mold half in a direction that may be parallel to the rib.

A particular problem arises when the rib has a hole, formed during the molding step. In this case, it is possible to provide a relief on the lateral surface of the ejector, thus reserving a volume that will create the hole once the piece out of the mold.

In this case, during the ejection of the part, it is possible to provide that the ejector moves both upwards, that is to say parallel to the plane of the rib, and laterally, away from the rib so as to disengage the relief from the hole.

Such a movement is known by the English name "up and away", or inclined rising wedge. This movement is not possible when the piece has a shoulder preventing the ejector laterally deviates from the rib ..

In this context, the invention aims to provide a manufacturing mold for making such parts. To this end, the invention relates to a mold for manufacturing a ribbed piece, the ribbed piece comprising a front face, a rear face and a rib formed on the rear face, the mold comprising first and second half-molds, movable relative to each other between a closed position in which the first and second half-molds are relatively closer to each other and delimit between them a molding cavity, and an open position in which the first and second half-molds are relatively more distant from each other; first and second inner surfaces of the first and second half-molds being respectively provided to form the front and rear faces of the workpiece; the second half-mold having a main portion and an ejector movable relative to the main portion in an ejection direction, the ejector having a body having an end surface defining a portion of the second inner surface and a side surface provided for form one side of the rib; the ejector having a slider movable relative to the body between an extended position in which a first end of the slider protrudes from the side surface, and a retracted position in which the first end of the slider is retracted into the body. In the molding step, that is to say when the material constituting the ribbed piece is introduced into the mold cavity, the slide is in the extended position. This creates a hole in the rib of the room.

To eject the part, the front end of the slide is retracted into the body of the ejector, concomitantly or after displacement of the ejector. It is thus possible to provide for the ejector a rectilinear displacement, typically substantially parallel to the rib. It is no longer necessary to provide for the ejector an additional lateral movement spacing vis-à-vis the rib.

As a result, the manufacturing mold can be used to make all kinds of parts, including parts with a shoulder that would prevent the ejector from moving transversely of the rib.

The manufacturing mold may also have one or more of the following characteristics, considered individually or in any technically possible combination: the normal to the lateral surface forms with the ejection direction an angle of between 60 ° and 120 ° ; the end surface has first and second zones connected to each other by a shoulder turned in a direction opposite to the lateral surface, the normal to the shoulder forming with the normal to the lateral surface an angle of between ° and 179 °; the first and second zones are offset with respect to each other in the direction of ejection; - The slider moves between its output and retracted positions in a direction of travel forming with the normal to the lateral surface an angle between -30 ° and + 30 °; - The body comprises a cavity in which the slide is housed free in translation relative to the body; the ejector comprises an elastic member urging the slide towards its retracted position; the ejector moves relative to the main part of the second half-mold between a molding position and an ejection position, the second half-mold comprising a drive mechanism forcing the slide in the extended position when the ejector is in the molding position; the drive mechanism comprises a cam surface formed on the main portion of the second half-mold, a second end of the cam follower slider and cooperating with the cam surface to force the slider into the extended position when the ejector is in molding position.

According to a second aspect, the invention relates to a method of manufacturing a ribbed piece comprising a front face, a rear face and a rib formed on the rear face, using a mold having the above characteristics: first and second half-molds in the closed position, the slider being in the extended position; - introducing a material into the mold cavity, the first end of the slider forming a hole in the rib; placing the first and second half-molds in the open position; - Ejecting the piece by moving the ejector relative to the main part of the second half-mold and by moving the slide from the extended position to the retracted position. Other features and advantages of the invention will emerge from the detailed description given below, by way of indication and in no way limiting, with reference to the appended figures, among which: FIG. 1 schematically illustrates the mold of manufacture of the invention in open position in a sectional view; - Figure 2 illustrates the mold of Figure 1, in the closed position, after injection of the ribbed piece in a sectional view; and - Figure 3 shows the second half-mold, after moving the ejector in a sectional view.

The mold shown in Figures 1 to 3 is provided for the manufacture of a ribbed piece of the type shown in Figures 2 and 3. The ribbed piece 3 has a front face 5, a rear face 7 and a rib 9 formed on the back side. Rib 9 has a hole 11.

The part 3 comprises a first part 15, a second part 17 and a shoulder 19 connecting the first and second parts 15 and 17 to each other. The rib 9 is formed on the first part 15. The second part 17 of the part 3 is offset towards the rear of the part relative to the first part 15. Thus, the rear of the shoulder 19 is located in a screw in a first direction T, of the rib 9.

The rib 9 extends from the rear face 7 along a second direction L, represented by the arrow L in FIGS. 1 to 3. The first direction is indicated by the arrow T in FIGS. 1 to 3. In the As shown, the rib 9 extends in a plane perpendicular to the first direction.

The manufacturing mold is typically an injection mold. Alternatively, it is of any other type.

The mold 1 comprises first and second half-molds 21, 23, visible in particular in FIG. 1. The first and second half-molds 21, 23 are movable relative to one another between a closed position in which the first and second half-molds 21, 23 are relatively closer to one another, and an open position in which the first and second half-molds 21, 23 are relatively further apart from each other. other. The open position is shown in FIG. 1. The closed position is shown in FIG.

Typically, the first and second half-molds 21, 23, move between their open and closed positions by a movement along the second direction which is here longitudinal.

In the closed position, the first and second half-molds 21, 23 delimit between them a molding cavity 25.

Typically, the molding cavity 25 has the shape of the part 3 to be manufactured.

More specifically, the first and second half-molds, 21 and 23, have respective first and second inner surfaces 27, 29 for forming respectively the front 5 and rear 7 faces of the part 3. In the closed position, the first and second internal surfaces 27 and 29 are vis-à-vis one another and delimit substantially all of the mold cavity.

As shown in the figures, the second half-mold 23 has a main portion 31 and an ejector 33 movable relative to the main portion 23 in an ejection direction E.

Hole 11 is typically through. Alternatively it is blind, and open on one side 13 of the rib 9 facing the ejector which is to the right in the representation of Figure 3. The ejector 33 moves in translation, exclusively in the direction of ejection. This ejection direction is for example parallel to the second direction. The ejector 33 has an end surface 35 defining a portion of the second inner surface 29, and a side surface 37 provided to form one side of the rib 9.

The end surface 35 has first and second zones 39, 41 connected to each other by a shoulder 43. The shoulder 43 forms a non-zero angle with respect to the first and second zones 39 and 41. The first and second zones 39, 41 second zones 39, 41 are provided to partially form the parts 15 and 17 of a rear side. The shoulder 43 is provided to form the shoulder 19 of the part, a rear side.

The first and second zones 39, 41 are offset with respect to each other in the direction of ejection. The second zone 41 is set back relative to the first zone 39 in the direction of ejection. The different orientations of the lateral surface 37, the first and second zones 39 and 41 and the shoulder 43 do not allow the part 3 a movement perpendicular to the ejection direction in the ejection position of the ejector 33.

Typically, the normal N1 at the shoulder 43 forms with the normal N2 at the lateral surface 37 an angle a1 between 91 ° and 179 °.

On the other hand, the normal N 2 at the lateral surface 37 forms with the ejection direction E an angle comprised between 60 ° and 120 °, preferably between 80 ° and 100 °. In one embodiment, the normal N2 at the side surface 37 forms with the ejection direction E an angle a2 of 90 °.

Thus, the ejector 33 has a projecting portion 45 delimited by the lateral surface 37, the shoulder 43 and the first zone 39, intended to form the recessed zone defined on the rear face of the part between the first part 15. , the rib 9 and the shoulder 19.

This projecting portion 45 protrudes with respect to the second zone 41 in the direction of ejection. The ejector 33 further comprises a slider 47, movable relative to the body 34 between an extended position (FIGS. 1 and 2) in which a first end 49 of the slider 47 projects relative to the lateral surface 37, and a position retracted into which the first end 49 of the slider is retracted into the body 34.

The first end 49 is intended to form the hole 11 of the rib 9. It has any suitable shape: circular, rectangular, etc.

Typically, the slider 47 moves between its output and retracted positions in a direction of displacement D forming with the normal N2 at the lateral surface 37 an angle of between -30 ° and + 30 °, preferably an angle of between -10 ° and 10 °.

In one embodiment, the slider 47 moves between its exit and retracted positions in a direction of travel forming with the normal N2 at the side surface 37 a zero angle.

The body 34 comprises a cavity 51 in which the slider 47 is housed.

The slider 47 is free in translation inside the cavity 51 relative to the body 34. The ejector 33 further comprises an elastic member 53, urging the slider 47 to its retracted position. The elastic member 53 is of any suitable type. In the example shown, the elastic member 53 is a compression spring.

The cavity 51 is substantially rectilinear. It crosses the ejector 34 from one side to the other. It comprises a central section 55 of relatively larger section, extended on both sides by two end sections 57 of relatively smaller sections. The end sections 57 are open. One of the sections 57 opens out at the level of the lateral surface 37. The other end section 57 opens out on an inclined surface 59 situated opposite the lateral surface 37. At each of its two opposite ends, the central section 55 has an annular surface 61, perpendicular to the central axis of the cavity 51. The annular surfaces 61 connect the peripheral wall of the central section 55 to the peripheral walls of the end sections 57. The elastic member 53 is supported on one side on a flange 63 rigidly fixed to the slider 47, and on the other side on the annular surface 61 facing the lateral surface 37.

As shown in the figures, the ejector 33 moves relative to the main portion 31 of the second half-mold between a molding position and an ejection position. The molding position is shown in Figures 1 and 2. The ejection position is shown in Figure 3. The ejector moves between its two positions in the direction of ejection, as indicated above.

To do this, the main part 31 comprises a channel 65 in which the ejector 33 is engaged. The channel 65 has a surface 67 placed vis-à-vis the side surface 37 when the ejector 33 is in its molding position. The surface 67 is provided to form, with the lateral surface 37, the rib 9 of the part 3.

In the molding position, the end surface 35 fits into the second inner surface 29. The ejector 33 is retracted inside the channel 65.

In the ejection position, the ejector 33 protrudes out of the channel 65 towards the molding cavity which is upward in the representation of FIG. 3. The end surface 35 is offset from the remainder of the second surface internal 29, in the direction of ejection. The cavity 51 and the slider 47 are located outside the channel 65. Similarly, the lateral surface 37 is located outside the channel 65. The inclined surface 59 is also located outside the channel 65.

Furthermore, the second half-mold 23 comprises a drive mechanism 69 forcing the slider 47 into its extended position when the ejector 33 is in the molding position.

The drive mechanism 69 is arranged to place the slider 47 in its retracted position as the ejector 33 moves from its molding position to its ejection position.

The slider 47 is driven for this purpose by the elastic member 53.

As can be seen in particular in FIG. 3, the drive mechanism 69 comprises a cam surface 71 formed on the main part 31 of the second half-mold 23, a second end 73 of the cam follower slide 47 and cooperating with the surface of the cam. cam 71 to force the slider 47 into the extended position when the ejector 33 is in the molding position.

In the example shown in the figures, the cam surface 71 is formed in the wall defining the channel 65. The cam surface 71 deviates from the ejector 33 in the first direction when it is followed towards the second internal surface. 29 according to the second direction.

In the molding position, the inclined surface 59 is in contact with the cam surface 71. Both surfaces have the same shape, and the same inclination.

As can be seen in FIG. 3, in the ejection position, the second end 73 of the slide protrudes in the first direction out of the cavity 51, at the inclined surface 59. The resilient member 53 presses on the collar 63 and urges the latter in the first direction until it bears on the annular surface 61 facing the inclined surface 59. This causes the second end 73 to exit. In this position, the first end 49 of the slide is retracted inside the cavity 51.

On the contrary, when the ejector 33 is in its molding position, the cam surface 71 forces the second end 73 of the slider to enter the cavity 51. The slider 47 is thus forced to move in the first direction towards the surface. lateral 37, against the restoring force of the elastic member 53. As a result, the flange 63 off the annular surface 61. This displacement causes the output of the first end 49 of the slide.

The method of manufacturing the ribbed piece 3 using the mold 1 described above will now be detailed. In the initial state, the two half-molds 21, 23 are in the open position.

The method comprises the following steps: - locating the first and second half-molds 21, 23 in the closed position, the slide 47 being in the extended position; - Introducing a material into the molding cavity 25, the first end 49 of the slider 47 forming the hole 11 in the rib 9; placing the first and second half-molds 21, 23 in the open position; - Ejection of the piece 3 by moving the ejector 33 relative to the main portion 31 of the second half-mold 23 and by moving the slide 47 from the extended position to the retracted position. In the initial state, the ejector 33 is in its molding position. The drive mechanism 69 causes the slider 33 to be in its extended position.

During the step of introducing the material into the molding cavity 25, the material will disperse and occupy the entire volume of the molding cavity 25. It flows until it comes to surround the first end 49 of the slide, as illustrated in FIG. 2. In the step of ejecting the part 7, the ejector 33 moves in translation along the direction of ejection, that is to say along the second direction in the example shown. . It drives the part 3 with it, this part being detached from the main part 31 of the second half-mold 23. Due to this displacement of the ejector 33 with respect to the main part 31, the inclined surface 59 of the ejector 33 is detached from the cam surface 71. Under the effect of the biasing of the elastic member 53, the slide 47 is then moved to its retracted position. The first end 49 of the slider 47 is extracted out of the hole 11. It is then possible to grasp the part 3 and separate it from the ejector 33 by moving the part 3 in the direction of ejection. The shoulder 19 of the piece does not prevent this movement.

The mold and method described above have multiple advantages.

They make it easy to manufacture parts having a shoulder such as the shoulder 19 described above, which prevents the ejector from moving in the first direction to disengage the ejector hole 11 of the rib.

Housing the slide in a body cavity makes the device particularly compact. The use of a resilient member urging the slide to its retracted position makes the process particularly simple.

The fact that the slider is moved in the extended position by a cam surface formed on the second half-mold also makes the device particularly mechanically simple.

The mold and the corresponding manufacturing method may have multiple variants.

The mold and the method may be designed to produce ribbed pieces having no shoulders such as the shoulder 19 described above.

The slider can be driven between its retracted and exited positions by other means than those described above. In particular, it is possible to provide in the main part of the second half-mold a groove, the rear end of the slide forming a dovetail driven in the first direction by the groove when the ejector moves towards its position. ejection.

The material constituting the ribbed piece can be of any type. This material is a plastic material, or a metal, or any other suitable material.

Claims (10)

1, -Production mold (1) of a ribbed piece (3), the ribbed piece (3) comprising a front face (5), a rear face (7) and a rib (9) formed on the rear face ( 7), the mold (1) comprising first and second half-molds (21, 23) movable relative to each other between a closed position in which the first and second half-molds (21, 23) are relatively closer to each other and delimit between them a molding cavity (25), and an open position in which the first and second half-molds (21,23) are relatively more distant one of the other; first and second inner surfaces (27, 29) of the first and second half-molds (21, 23) being respectively provided to form the front and rear faces (5, 7) of the workpiece (3); the second half-mold (23) having a main portion (31) and an ejector (33) movable relative to the main portion (31) in an ejection direction, the ejector (33) having a body (34) having an end surface (35) defining a portion of the second inner surface (29) and a side surface (37) provided to form one side of the rib (9); the ejector (33) having a slider (47) movable relative to the body (34) between an extended position in which a first end (49) of the slider (47) projects from the side surface (37), and a retracted position in which the first end (49) of the slider (47) is retracted into the body (34). 2, - Mold according to claim 1, wherein the normal to the lateral surface (37) forms with the direction of ejection an angle between 60 ° and 120 °. 3, - mold according to any one of the preceding claims, wherein the end surface (35) has first and second zones (39, 41) connected to one another by a shoulder (43) rotated in one direction opposed to the side surface (37), the normal (N1) at the shoulder (43) forming with the normal (N2) at the side surface (37) an angle (cry) of between 91 ° and 179 °. 4, - Mold according to claim 3, wherein the first and second zones (39, 41) are offset relative to each other in the direction of ejection. 5, - mold according to any one of the preceding claims, wherein the slider (47) moves between its outward and retracted positions in a direction of travel forming with the normal (N2) to the side surface (37) an angle included between -30 ° and + 30 °. 6. - mold according to any one of the preceding claims, wherein the body (34) comprises a cavity (51) wherein the slide (47) is housed free in translation relative to the body (34). 7. - Mold according to any one of the preceding claims, wherein the ejector (33) comprises an elastic member (53) urging the slide (47) to its retracted position. 8. Mold according to any one of the preceding claims, wherein the ejector (33) moves relative to the main part (31) of the second half-mold (23) between a molding position and a position of ejection, the second half mold (23) having a drive mechanism (69) forcing the slider (47) to the extended position when the ejector (33) is in the molding position. The mold of claim 8, wherein the drive mechanism (69) comprises a cam surface (71) formed on the main portion (31) of the second half-mold (23), a second end (73). cam follower slider (47) cooperating with the cam surface (71) to force the slider (47) to the extended position when the ejector (33) is in the molding position. 10. - Method for producing a ribbed piece (3), the ribbed piece (3) comprising a front face (5), a rear face (7) and a rib (9) formed on the rear face (7), using a mold (1) according to any one of the preceding claims, the method comprising the following steps: - placing the first and second half-molds (21, 23) in the closed position, the slide (47) being in the extended position ; - introducing a material into the molding cavity (25), the first end (49) of the slider (47) forming a hole (11) in the rib (9); placing the first and second half-molds (21, 23) in the open position; - Ejecting the piece (3) by moving the ejector (33) relative to the main part (31) of the second half-mold (23) and by moving the slide (47) from the extended position to the retracted position .