Mould fitted with an improved pusher device

Abstract

The mould (1) comprises a base (2), a removable shim (3), a belt (5), and a pusher device (7) capable of moving the base (2) and the belt (5) away from one another automatically. The pusher device comprises a pusher (9) bearing vertically on the base, a hook pin (10) movable vertically between an upper position at a distance above the pusher and a lower position bearing on the pusher, and a locking assembly (11) which is secured to the belt and locks the hook pin in the lower position. The pusher comprises a spring (12) which is compressed when the hook pin is in the lower position, this spring then exerting an upward pushing force on the hook pin. The belt has a through-opening (34) in which the hook pin is housed, extending therethrough, an upper portion of the hook pin extending above the belt when said pin is in the upper position.

Description

Mold equipped with an improved pusher device TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of molding, and in particular resin transfer molding, using a mold comprising a base, a cover and at least one intermediate wedge located between the base and the cover.

[0002] The present invention relates to a push device capable of moving the base and the belt apart from each other automatically when the pressure holding the base and the cover against each other is released. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Typically, in resin transfer molding, the molded part material has a coefficient of thermal expansion that is different from the coefficient of thermal expansion of the mold material, which creates unwanted stresses in the molded part as it cools. These stresses can damage the part and make it difficult to demold, as the molded part may become stuck in the mold due to clamping.

[0004] In order to overcome these drawbacks, document FR 3001653 A1 in the name of the applicant and shown in [Fig. 1] and [Fig. 2] discloses a mold 1' comprising at least one removable wedge 3 located between a base 2 and a belt 5 also fulfilling the role of cover for the mold 1'. Each wedge 3 has an inclined face 4 which slides along a complementary inclined face 6 provided on the belt 5 when the mold 1' is open. The mold 1' also includes a pusher device 7' which automatically moves the base 2 and the belt 5 apart from each other when the pressure holding the base 2 and the belt 5 against each other during molding is released, allowing each wedge 3 to slide upwards and laterally away from the molded part 8, to prevent the wedges 3 from exerting stress on the molded part 8.

[0005] When no pressure is exerted to hold the base and the belt against each other, the pusher device of document FR 3001653 A1 keeps these two parts in the separated position and the mold is therefore in the partially open position. However, it may be desired for the mold to be in the closed position when it is in the rest position, while nevertheless incorporating a pusher device which automatically separates the base and the belt from each other at the end of molding, when the pressure holding the base and belt together is released.

[0006] This allows, in particular, the shims and the belt to be manually and delicately positioned on the reinforcement intended to be impregnated with resin before closing the mold, while ensuring that the reinforcement is correctly positioned in the base, without being creased, folded and / or stuck by the shims. This also ensures that the reinforcement is correctly arranged and put in place when it is made up of several layers which must be carefully positioned in relation to each other and pressed against each other before molding.

[0007] The object of the invention is therefore to provide a modified pusher device, which separates the base and the belt from each other automatically when a pressure which held them against each other is released, but which does not separate these parts before said pressure has been exerted, that is to say which allows the mold to remain in the closed position by gravity when the base and the belt are placed against each other before pressure is exerted on the mold to keep these parts pressed against each other during the injection of the resin. SUMMARY OF THE INVENTION

[0008] The invention provides a solution to the problems discussed above by providing a pusher device comprising two parts which are initially spaced apart when the mold is closed but no pressure has yet been exerted to hold the base and the belt against each other, and which are mutually locked after this pressure has been exerted, so that when the pressure is released the base and the cover are moved apart from each other automatically by the pusher device.

[0009] One aspect of the invention relates to a mold comprising: a base, a removable wedge, a belt, a pusher device capable of moving the base and the belt away from each other automatically, where in the closed position of the mold, the wedge is in vertical support on the base, the belt is in vertical support on said wedge and on the base, the wedge is in lateral support against the belt, and the wedge, the base and the belt delimit a hollow molding volume, in which the pusher device comprises: a first part, designated as a pusher, in vertical support on the base, a second part, designated as a hook axis, movable vertically between a high position in which the hook axis is at a distance above the pusher and a low position in which the hook axis is in support on the pusher, a locking assembly, integral with the belt, which locks the hook axis in the low position, and the pusher comprises a spring which is compressed when the hook axis is in the low position, this spring then exerting a pushing force on the hook axis aimed at moving it to the high position,and the belt has a through hole through which the hook pin is housed, an upper portion of the hook pin extending above the belt when the hook pin is in the upper position.,

[0010] In addition to the features just mentioned in the preceding paragraph, the mold according to one aspect of the invention may have one or more additional features from among the following, considered individually or according to all technically possible combinations: the hook axis comprises a vertical shaft extending along an axis Y-Y' substantially parallel to a demolding axis and having a locking surface perpendicular to the axis Y-Y', the locking assembly comprises at least one moving part movable between an engagement position and a disengagement position, the locking assembly comprises a spring which pushes the moving part into the locking position, when the moving part is in the engagement position, the locking surface of the hook axis bears against a face lower part of the movable part of the locking assembly, and when the movable part is in the disengaged position, it is not in contact with the locking surface. the outer lateral face of the vertical shaft or an outer face of the movable part of the locking assembly has an inclined ramp forming a sliding ramp between the vertical shaft and the movable part, and the hook pin is movable vertically in an intermediate position located between the upper position and the lower position and in which the inclined ramp laterally moves the movable part from its unlocking position to its locking position. the inclined ramp of the vertical shaft is in the form of a conical or frustoconical portion tapering downwards and provided at the lower end of the vertical shaft, and the locking surface of the hook pin is an upper face of the conical or frustoconical portion.the locking assembly comprises two moving parts facing each side of the hook axis and each pushed towards said hook axis by a spring. the pusher comprises a lower support part, a vertically movable upper support part and a spring elastically deformable between a rest state and a compressed state in which it exerts a pushing force between the two support parts. the lower support part comprises a tubular part having a hollow volume in the lower part, the pusher comprises a vertical rod fixed to the upper support part and slidably mounted in the tubular part, and the height of the hollow volume is greater than the distance traveled by the vertical rod when the spring passes from the rest state to the compressed state.the tubular part of the lower support piece has a narrowing in the upper part, and the vertical rod has a shoulder in its lower part, this shoulder being pressed against a lower face of the narrowing of the lower support piece by the thrust force of the spring. the upper part of the vertical rod has a threaded part, the upper support piece comprises a threaded orifice, and the threaded part of the vertical rod is screwed into the threaded orifice of the upper support piece. the mold comprises a cover located above the belt, which cover has a through orifice which communicates with the through orifice of the belt, the hook axis being housed in the through orifice of the belt and in the through orifice of the cover, and the upper part of the hook axis extending above the cover when the hook axis is in the high position. the base has a recessed housing in which the lower support piece of the pusher is at least partially housed. the wedge has an inclined face, the belt has an inclined face, and in the closed position of the mold the inclined face of the wedge bears laterally on the inclined face of the belt.

[0011] Another aspect of the invention relates to a molding method using a mold as described above, comprising the following steps: closing the mold; applying pressure to the mold and the pusher device, and changing said pusher device from an unlocked state to a locked state; releasing the pressure on the mold and the pusher device, and automatically moving the base and the belt away from each other by the pusher device; and opening the mold.

[0012] According to one aspect of the invention, the molding method is a resin transfer molding method.

[0013] By virtue of the invention, after closing the mold and before any pressure force has been exerted on it, the belt is in free support against the base and each wedge, and the hook axis is in the high position, which makes it possible in particular to ensure that the reinforcement to be impregnated with resin is well positioned and well immobilized. After applying pressure to the mold, for example by a press, the upper part of the hook axis is forced downwards, which moves the hook axis in low position where it is engaged in locking by the locking assembly and compresses the spring of the pusher device. When the pressure on the mold is released, the spring of the pusher device automatically pushes the hook pin upwards, which in turn lifts the belt via the locking assembly, which advantageously allows each wedge to slide upwards and laterally away from the molded part. Thus, the mold of the invention does not generate unwanted stresses in the part during its molding and the demolding of the finished part is also facilitated.

[0014] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0015] The figures are presented for information purposes only and in no way limit the invention.

[0016] [Fig. 1] is a schematic sectional side view of a mold according to the prior art in the partially open position in the absence of pressure to maintain the mold closed.

[0017] [Fig. 2] is a view similar to [Fig. 1] where the mold is in the closed position with a pressure force exerted on the mold.

[0018] [Fig. 3] is an overall view of a pusher device according to the invention.

[0019] [Fig. 4] is a sectional view of a pusher device of the invention according to section plane IV-IV shown in [Fig. 3].

[0020] [Fig. 5] is a schematic sectional side view of a mold according to the invention in the closed position but without any pressure force being exerted on the mold.

[0021] [Fig. 6] is a view similar to [Fig. 5], where the mold is in the closed position with a pressing force exerted on the mold, the pusher device being in the locked position.

[0022] [Fig. 7] is a view similar to [Fig. 5] and [Fig. 6], where the mold is in the partially open position in the absence of pressure to hold the mold closed.

[0023] [Fig. 8] [Fig. 9] are simplified schematic views illustrating variants of the pusher device according to the invention.

[0024] [Fig. 10] [Fig. 11] are schematic top sectional views of a pair of half-rings of the pusher device in the closed and open position.

[0025] [Fig. 12] is a schematic sectional top view of a variant of the pair of half-rings of [Fig. 10]. DETAILED DESCRIPTION

[0026] The figures are presented for information purposes only and in no way limit the invention.

[0027] By convention, in the present application, when referring to the mold according to the invention, by upper, lower, above and below we refer to the mold as shown in the drawings. Similarly, by vertical we refer to a direction along an axis extending perpendicular to the main plane in which the base of the mold extends. In the figures, the axis Y-Y' is vertical and corresponds substantially to a demolding axis, that is to say an axis along which the different parts of the mold are usually moved away from each other when it is opened.

[0028] The mold 1 according to the invention comprises at least one removable wedge 3 located between a base 2 and a belt 5 intended to hold the wedges 3 in position in the mold 1 when it is closed. It may also comprise a cover 15 provided above the belt 5.

[0029] When the mold 1 is in the closed position, each wedge 3 is in contact with the base 2. The belt 5, the wedge 3 and the base 2 then delimit a hollow molding volume 38 where a reinforcement can be impregnated with resin to form a molded part 8.

[0030] At least one shim 3 is provided to be partially in contact with the molded part 8. This shim preferably has an inclined face 4 which slides preferentially along a complementary inclined face 6 provided on the belt 5 when the mold 1 is opened. When the mold 1 is closed, the inclined face 4 of each shim 3 can also be located in the extension of an inclined face 39 of the base 2.

[0031] The mold 1 according to the invention also comprises a pusher device 7 comprising a pusher 9, a hook axis 10 and a locking assembly 11.

[0032] The hook axis 10 is movable vertically between a high position in which it is at a distance from the pusher 9 and a low position in which it rests on the pusher 9. It comprises a vertical shaft 13 extending along an axis Y-Y' and has a horizontal locking surface 16.

[0033] The belt 5 has a through hole 34 through which the hook pin 10 is housed, an upper part of the hook pin 10 extending above the belt 5 when the hook pin 10 is in the high position.

[0034] When the mold 1 comprises a cover 15 located above the belt 5, this cover 15 has a through orifice 35 which communicates with the through orifice 34 of the belt 5. The hook axis 10 is housed in the through orifice 34 of the belt 5 and in the through orifice 35 of the cover 15, and the upper part of the hook axis 10 extends above the cover 15 when the hook axis 10 is in the high position.

[0035] The locking assembly 11, integral with the belt 5, is provided to lock the hook pin 10 when the latter is in the low position so as to prevent it from rising without this also lifting the belt 5. The locking assembly 11 is preferably mounted in a housing 40 extending horizontally in the belt 5. It comprises at least one moving part 17 movable between an engagement position and a disengagement position. In the engagement position, the locking surface 16 of the hook pin 10 is preferably in abutment against a lower face 19 of the moving part 17. In the disengagement position, the moving part 17 is not in contact with the locking surface 16. It can then be at a distance from the vertical shaft 13. The locking assembly 11 comprises a spring 18 which tends to push the moving part 17 into the locking position.

[0036] An external lateral face 14 of the vertical shaft 13 or an external face 20 of the moving part 17 of the locking assembly 11 preferably has an inclined ramp 21, 22 forming a sliding ramp between the vertical shaft 13 and the moving part 17 provided so that when the hook axis 10 is in an intermediate position located between the high position and the low position, the ramp inclined 21, 22 laterally moves the moving part 17 from its unlocking position to its locking position by the sliding contact of the vertical shaft 13 against the moving part 17 of the locking assembly 11.

[0037] The inclined ramp 21 of the vertical shaft 13 is preferably in the form of a conical or frustoconical part 23 tapering downwards and provided at the lower end of the vertical shaft 13 and the locking surface 16 of the hook axis 10 is an upper face 24 of the conical or frustoconical part 23.

[0038] The moving part 17 of the locking assembly 11 preferably has an inclined ramp 22, the lower part of which is directed towards the vertical shaft 13.

[0039] Two variants are shown in [Fig. 8]-[Fig. 9] where either it is the vertical shaft 13 which has a ramp 21, or it is the moving part 17 which has a ramp 22.

[0040] As shown by way of example in [Fig. 10]-[Fig. 12], the locking assembly 11 preferably comprises two moving parts 17, for example in the form of a half-ring, facing each side of the hook axis 10 to form a ring, and each pushed towards said hook axis 10 by a spring 18, the mutual movement of the two moving parts 17 being preferably guided by a pair of screws 41 screwed into one of the two moving parts 17 and slidably mounted in the other moving part 17. The two moving parts 17 are shown in contact in [Fig. 10]-[Fig. 12], and in the separated position in [Fig. 11],

[0041] It will be noted that a minimum force is applied by the springs 18 to keep the moving parts 17 in contact. The stroke of said springs 18 allows the conical or truncated part 23 of the hook axis 10 to pass and to resume its locked shape thereafter. The internal diameter of the ring formed by the moving parts 17 in contact is greater than the diameter of the vertical shaft 13.

[0042] The pusher 9 preferably comprises a lower support piece 25, an upper support piece 26 movable vertically and a spring 12 elastically deformable between a rest state and a compressed state in which it exerts a thrust force between the two support pieces 25, 26. The pusher 9 is supported vertical on the base 2, preferably via its lower support piece 25.

[0043] The lower support piece 25 preferably comprises a tubular part 27 having a hollow volume 37 in the lower part, the pusher 9 comprises a vertical rod 29 fixed to the upper support piece 26 and slidably mounted in the tubular part 27, and the height of the hollow volume 37 allows movement of the vertical rod 29 when the spring 12 passes from the rest state to the compressed state.

[0044] The tubular part 27 of the lower support piece 25 preferably has a narrowing 28 in the upper part, and the vertical rod 29 has a shoulder 30 in its lower part, this shoulder 30 being pressed against a lower face 31 of the narrowing 28 of the lower support piece 25 by the thrust force of the spring 12.

[0045] Preferably, the upper part of the vertical rod 29 has a threaded part 32, the upper support piece 26 comprises a threaded orifice 33, and the threaded part 32 of the vertical rod 29 is screwed into the threaded orifice 33 of the upper support piece 26, which makes it possible to adjust the vertical position of the upper support piece 26 relative to the vertical rod 29.

[0046] The lower support piece 25 may bear directly on the base 2 or be at least partially housed in a recess 36 formed as a hollow in the base 2.

[0047] The operation of the push device 7 will now be explained in relation to [Fig. 5]-[Fig. 7],

[0048] In [Fig. 5], the mold is in the closed position, without any pressure being exerted on it. The hook axis 10 is in the high position, its upper part protruding upwards outside the mold 1. It is located at a distance from the pusher. Although this is not necessarily necessary, it is shown in contact with the locking assembly 11.

[0049] Pressure is then applied to the top of the mold 1, for example by a press, to keep it closed during resin injection. This pressure is also exerted on the upper projecting part of the hook axis 10, which then moves from its high position to its low position, moving the parts apart in the process. mobile 17 of the locking assembly 11 and pressing on the pusher 9 to lower its upper support piece 26 and compress its spring 12.

[0050] In the low position of the hook axis 10 (see [Fig. 6]), the lower face 19 of the moving parts 17 of the locking assembly 11 come to bear against the locking surface 16 of the hook axis 10 to lock it in the low position.

[0051] When the pressure applied to the top of the mold 1 is released (see [Fig. 7]), the hook axis 10 rises, pushed by the compressed spring 12 of the pusher 9. As it is engaged in locking with the locking assembly 11, the hook axis 10 also tends to move the locking assembly 11 upwards. The latter being integral with the belt 5, the latter is therefore moved upwards, as well as the cover 15 if it is present.

[0052] The separation of the base 2 and the belt 5 from each other by the pusher device 7 is carried out automatically, for example by a distance of the order of a few millimeters, when the pressure applied to the mold is released. If necessary, this preferentially frees up a space allowing each wedge 3 to slide upwards along the inclined contact face 6 of the belt 5 and to slide laterally on the base 2 away from the molded part 8.

[0053] The invention also relates to a molding method, preferably a resin transfer molding method, using a mold 1 according to the invention, and comprising the following steps: closing the mold 1; applying pressure to the mold 1 and the pusher device 7, and switching said pusher device 7 from the unlocked state to the locked state; releasing the pressure on the mold 1 and the pusher device 7, and automatically moving the base 2 and the belt 5 away from each other by the pusher device 7; and opening the mold 1.

[0054] The unlocking mode of the push device 7 depends on the design of the locking assembly 11. 11 is preferably based on an extraction of the hook axis 10 from below when opening the mold, the vertical shaft 13 passing through the ring formed by the moving parts 17.

[0055] According to a variant of the invention, it is possible to unlock the pusher device by moving the moving parts 17 away from the hook axis 10. This moving away can be achieved by a magnetic or mechanical device, not shown. The unlocking of the pusher device 7 can for example be achieved by introducing a hollow tube around the vertical shaft 13 in order to come to bear on the inclined ramp 22 of each moving part 17, and to temporarily move them away from the hook axis 10, which allows it to be raised to the high position.

[0056] Unless otherwise specified, the same element appearing in different figures has a single reference.

Claims

CLAIMS

1. Mold (1) comprising: - a base (2), - a removable wedge (3), - a belt (5), - a pusher device (7) capable of moving the base (2) and the belt (5) away from each other automatically, where - in the closed position of the mold (1), the wedge (3) is in vertical support on the base (2), the belt (5) is in vertical support on said wedge (3) and on the base (2), the wedge (3) is in lateral support against the belt (5), and the wedge (3), the base (2) and the belt (5) delimit a hollow molding volume (38), - characterized in that the pusher device (7) comprises: - a first part, designated as a pusher (9), resting vertically on the base (2), - a second part, designated as a hook axis (10), movable vertically between a high position in which the hook axis (10) is at a distance above the pusher (9) and a low position in which the hook axis (10) is resting on the pusher (9), - a locking assembly (11), integral with the belt (5), which locks the hook axis (10) in the low position, and in that - the pusher (9) comprises a spring (12) which is compressed when the hook axis (10) is in the low position, this spring (12) then exerting a pushing force on the hook axis (10) aimed at moving it to the high position, and - the belt (5) has a through hole (34) through which the hook pin (10) is housed, an upper part of the hook pin (10) extending above the belt (5) when the hook pin (10) is in the high position.

2. Mold (1) according to claim 1, characterized in that: - the hook axis (10) comprises a vertical shaft (13) extending along an axis Y-Y' substantially parallel to a demolding axis and having a locking surface (16) perpendicular to the axis Y-Y', - the locking assembly (11) comprises at least one moving part (17) movable between an engagement position and a disengagement position, - the locking assembly (11) comprises a spring (18) which pushes the moving part (17) into the locking position, - when the moving part (17) is in the engagement position, the locking surface (16) of the hook axis (10) bears against a lower face (19) of the moving part (17) of the locking assembly (11), and - when the moving part (17) is in the disengaged position, it is not in contact with the locking surface (16).

3. Mold (1) according to claim 2, characterized in that: - an external lateral face (14) of the vertical shaft (13) or an external face (20) of the moving part (17) of the locking assembly (11) has an inclined ramp (21, 22) forming a sliding ramp between the vertical shaft (13) and the moving part (17), and in that - the hook axis (10) is movable vertically in an intermediate position located between the high position and the low position and in which the inclined ramp (21, 22) laterally moves the movable part (17) from its unlocking position to its locking position.

4. Mold (1) according to claim 3, characterized in that: - the inclined ramp (21) of the vertical shaft (13) is in the form of a conical or truncated part (23) tapering downwards and provided at the lower end of the vertical shaft (13), and in that - the locking surface (16) of the hook axis (10) is an upper face (24) of the conical or truncated part (23).

5. Mold (1) according to any one of the preceding claims, characterized in that the locking assembly (11) comprises two moving parts (17) facing each side of the hook axis (10) and each pushed towards said hook axis (10) by a spring (18).

6. Mold (1) according to any one of the preceding claims, characterized in that the pusher (9) comprises a lower support piece (25), an upper support piece (26) movable vertically and a spring (12) elastically deformable between a rest state and a compressed state in which it exerts a thrust force between the two support pieces (25, 26).

7. Mold (1) according to the preceding claim, characterized in that the base (2) has a housing (36) shaped as a hollow in which the lower support piece (25) of the pusher (9) is at least partially housed.

8. Mold (1) according to any one of the preceding claims, characterized in that the mold (1) comprises a cover (15) located above the belt (5), which cover (15) has a through orifice (35) which communicates with the through orifice (34) of the belt (5), the hook axis (10) being housed in the through orifice (34) of the belt (5) and in the through orifice (35) of the cover (15), and the upper part of the hook axis (10) extending above the cover (15) when the hook axis (10) is in the high position.

9. A molding method using a mold (1) according to any one of the preceding claims, characterized in that it comprises the following steps: - closing the mold (1); - applying pressure to the mold (1) and the pusher device (7), and switching said pusher device (7) from an unlocked state to a locked state; - release of the pressure on the mold (1) and the pusher device (7), and automatic moving away of the base (2) and the belt (5) from each other by the pusher device (7); and - opening the mold (1).

10. A molding method according to the preceding claim, characterized in that the molding method is a resin transfer molding method.

Images