Molded unit with magnetic bistable device

Abstract

The present invention relates to a container molding unit (18), comprising: two mold bases (22, 24); a locking device (42) for locking the mold bases (22, 24) in a closed position; a bistable device (62), comprising a fixed component (64) and a component (66) movable between two stable extreme positions (P1, P2); characterized in that the movable component (66) has a movable magnetic dipole (68), and the fixed component (64) has a fixed magnetic dipole (70), and the fixed magnetic dipole (70) remotely applies a magnetic force (Fm) to the movable magnetic dipole (68) to force the movable component (66) to move to one or the other of the two stable extreme positions (P1, P2). According to a second aspect of the present invention, there is provided: a blowing device (21) which is movable in translation relative to a support (20) between the following two stable extreme positions: a blowing position in which the blowing device contacts the upper surface of the mold to blow the preform; and a stowed position in which the preform is allowed to be introduced or the container is removed; and a bistable device (62) having: a first member (64) fixed relative to the support (20); and a second movable member (66) connected to the blowing device (21) between two stable extreme positions (P1, P2) located on both sides of an unstable equilibrium intermediate position (P0), and being movably connected to the blowing device (21), the movable member (66) interacting with the fixed member (64) to force the blowing device (21) to move to the blowing position or stowed position corresponding to each stable extreme position (P1, P2).

Description

Technical Field

[0001] The invention relates to the field of molding units for molding containers, in particular by blowing preforms of thermoplastic material, the molding unit comprising two mold supports, each of which is intended to support a portion of a mold, mounted to be movable relative to one another between an open position and a closed position, in which the two mold supports can be locked by a locking device. The molding unit is particularly equipped with a bistable device which forces the locking device to move to a locked position or an unlocked position corresponding to each of the stability extremes of the bistable device. Background Art

[0002] The invention relates to a moulding unit for equipping a moulding station for mass-moulding containers made of thermoplastic material. In such a station, hot preforms are blow-moulded into finished containers in moulds. As is known, each mould is made of at least two mould parts which can be joined together to reconstitute the complete mould cavity of the container to be made.

[0003] Each mold is mounted in an associated molding unit. In order to be able to produce different types of containers, each mold part is removably fixed in an associated mold base of the molding unit. The mold base is movable relative to each other between an open position in which the two mold parts are separated and a closed position in which the two mold parts are joined. When it is desired to change the container type, it is only necessary to remove the current mold from the mold base and replace it with a new mold.

[0004] In order to be able to manufacture containers in large quantities, a plurality of molding units are supported on the periphery of a continuously rotating turntable. The preforms are received into the mold at a defined input point and the containers are removed from the mold at a defined output point. In order to be able to insert new preforms and remove finished containers, the mold carrier is controlled in its open position. Thus, the mold is held in the open position during its travel over the angular sector extending from the output point to the input point.

[0005] The preform is formed into a container by blowing or stretch blowing in the molding unit during the transport from the input point to the output point. During its entire travel from the input point to the output point, the mold carrier must be in a closed position in which the two mold parts are engaged.

[0006] In practice, in order to avoid damage to the mold when it is closed, at least one of the two mold parts is floated with a limited clearance on its mold base. During blowing, a compressed fluid at the same pressure as the blowing fluid, for example 40 bar, is injected into the compensation chamber between the mold base and the floating mold part, so that the floating mold part rests on the other mold part. In this way, containers are obtained whose joint surfaces are barely visible.

[0007] However, if the mold base is not held in its closed position when the pressure fluid is injected into the compensation chamber, the floating mold part is pushed by the pressure with sufficient force to break free of the fasteners with which it is fastened to the mold base. As a result, the mold part can be ejected. Such a mold part may weigh tens of kilograms. The ejection of a mold part can therefore cause serious damage to the molding station and a risk of endangering the health of operators located nearby.

[0008] To ensure that the two mold parts are well joined together without causing the mold bases to open, the mold bases are locked in a closed position by a controlled locking device. The locking device has a locking member, which is mounted on one of the mold bases so as to be movable between a locked position and an unlocked position, in which the locking member cooperates with a locking surface of the other mold base to prevent the mold bases from opening, and in which the locking member is retracted relative to the locking surface to allow the mold bases to open.

[0009] The movement of the locking member between its locked position and unlocked position is generally controlled by a cam-type control member. The cam is fixedly arranged on a fixed base, wherein the turntable is rotatably mounted on the base, and the mold base equipped with the locking member has a cam follower, which is connected to the locking member and controls the movement of the locking member by cooperating with the cam.

[0010] To ensure good functioning of the moulding unit, it is important to ensure that the locking element is correctly controlled in one or the other of its locked or unlocked positions and that the locking element does not remain stuck in an intermediate position which does not allow the locking element to open or close correctly.

[0011] To this end, it is known to equip such a molding unit with a bistable device having two stable positions corresponding to the locked position and the unlocked position of the locking element. Thus, when the locking element is in an intermediate position, the bistable device forces the locking element to move to one or the other of its locked or unlocked positions. The stable position to which the locking element is urged depends on the position of the locking element relative to the unstable equilibrium position of the bistable device.

[0012] The known bistable device works by mechanical contact between a movable member, which is movably mounted on the die carrier and is movably connected to the locking element, and a fixed member. The movable member is provided with a cam. The die carrier carries the fixed member, which is formed by a cam follower having a roller which is elastically pressed against the cam of the movable member. The profile of the cam is designed so that the force exerted by the cam follower on the cam pushes the movable member into one or the other of its stable positions.

[0013] Such a bistable device must exert sufficient holding force to keep the movable member in each of its stable positions to prevent any accidental movement of the locking member, especially under the action of gravity or centrifugal force. In contrast, the cam-type control member of the locking member is designed to overcome the holding force and thus control the locking member to another stable position.

[0014] This mechanical contact arrangement functions quite satisfactorily, but requires periodic maintenance operations, in particular for lubricating the mobile components of the cam follower and the rollers, or for replacing components in contact with each other that are subject to wear.

[0015] This maintenance operation must be performed frequently, for example about once a week. The maintenance operation takes about 15 minutes for each molding unit. However, a blowing station generally has a plurality of molding units. Therefore, this maintenance operation requires stopping the equipment for several hours and / or requires several operators to perform.

[0016] Therefore, there is a need to shorten the time and / or reduce the manpower required for servicing the bistable device of each molding unit. Summary of the invention

[0017] According to a first embodiment, the present invention provides a thermoplastic material container forming station, the forming station having:

[0018] a container-moulding unit, in particular a unit for moulding containers by blowing preforms;

[0019] - bracket;

[0020] - a blowing device movable in translation relative to the support between two stable extreme positions: a blowing position in which the blowing device is in contact with the upper surface of the mold to blow the preform; and a stowed position allowing the introduction of a preform or the removal of a container;

[0021] - A bistable device having:

[0022] a first fixing member fixed relative to the support,

[0023] - A second movable member, which can move between two stable limit positions located on both sides of the unstable equilibrium middle position, is connected to the blowing device, the second movable member is movably connected to the blowing device, and the second movable member interacts with the first fixed member to force the blowing device to move to the blowing position or the stowed position corresponding to each stable limit position.

[0024] The forming station is characterized in that the second movable member has a first magnetic dipole, called the movable magnetic dipole, and the first fixed member has at least one second magnetic dipole, called the fixed magnetic dipole, which remotely applies a magnetic force to the movable magnetic dipole to force the second movable member to move to one or the other of the two stable extreme positions, regardless of the position of the second movable member between the two stable extreme positions.

[0025] According to a second embodiment, the present invention provides a thermoplastic material container forming station, the forming station having:

[0026] a container-moulding unit, in particular a unit for moulding containers by blowing preforms;

[0027] - a first mold base and a second mold base, each for supporting a portion of the mold, the first mold base and the second mold base being mounted to be movable relative to each other between an open position separated from each other and a closed position for engagement;

[0028] - a locking device for locking the first mold base and the second mold base in a closed position, the locking device having at least one locking member mounted on the second mold base to be movable between a locked position and an unlocked position, in which the locking member cooperates with at least one locking surface of the first mold base to prevent the first mold base and the second mold base from opening, and in which the locking member is retracted relative to the locking surface to allow the first mold base and the second mold base to open,

[0029] - A bistable device having:

[0030] a first fixing member fixed relative to the second die holder,

[0031] - A second movable member is mounted on the second mold base so as to be movable between two stable limit positions on both sides of the unstable equilibrium intermediate position, the second movable member is movably connected to the locking member, and the second movable member interacts with the first fixed member to force the locking device to move to a locking position or an unlocking position corresponding to each stable limit position.

[0032] The forming station is characterized in that the second movable member has a first magnetic dipole, called the movable magnetic dipole, and the first fixed member has at least one second magnetic dipole, called the fixed magnetic dipole, which remotely applies a magnetic force to the movable magnetic dipole to force the second movable member to move to one or the other of the two stable extreme positions, regardless of the position of the second movable member between the two stable extreme positions.

[0033] Advantageously, the second embodiment may have one or more of the following features, taken alone or in combination, with respect to the forming station:

[0034] - the movement of the second movable member is stopped at two stable limit positions by the associated mechanical stops, the repulsive force exerted by each fixed magnetic dipole on each movable magnetic dipole being sufficient to keep the locking member in a locked position or an unlocked position corresponding to one or the other of the two stable limit positions of the second movable member;

[0035] - the second movable member is mounted on the second mold base so as to be able to slide along a linear path between two stable limit positions;

[0036] - a second movable member is mounted on the second mold base so as to be pivotable about a pivot axis between two stable extreme positions, the movable magnetic dipole being fixed to the second movable member eccentrically with respect to the pivot axis;

[0037] Advantageously, the first and / or second embodiment may have one or more of the following features with respect to the magnetic dipole:

[0038] - the fixed magnetic dipole acts on the movable magnetic dipole by magnetic repulsion by exerting a repulsive force on the movable magnetic dipole to push the second movable member to one or the other of the two stable extreme positions;

[0039] -Magnetic dipoles always emit a magnetic field, such as permanent magnets;

[0040] - the variation of the repulsive force with the position of the second movable member has a slope connecting two extreme values ​​of opposite signs, the at least one fixed magnetic dipole being designed so that in each of the two extreme stable positions, the norm of the force exerted on the at least one movable magnetic dipole is between 30 Newtons and 100 Newtons, for example equal to about 60 Newtons;

[0041] - the movable magnetic dipoles and the fixed magnetic dipoles are designed so that in each of the two extreme stable positions, the norm of the force exerted on at least one movable magnetic dipole is equal to the local extreme value;

[0042] - each fixed magnetic dipole has a polar axis oriented orthogonal to the path of the first fixed member, a magnetic pole of each fixed magnetic dipole, called the active magnetic pole, being arranged facing the path of the mobile magnetic dipole;

[0043] - the first fixed member has a plurality of fixed magnetic dipoles, all of which have active magnetic poles of the same polarity;

[0044] - each mobile magnetic dipole has a polar axis oriented in the direction of its path, each mobile magnetic dipole has a magnetic pole, called a "repelling magnetic pole", the polarity of which is identical to the polarity of the active magnetic pole of the fixed magnetic dipole, which is facing the active magnetic pole when the second mobile member is in an intermediate position between the two extreme stable positions;

[0045] - each fixed magnetic dipole has a polar axis oriented parallel to the path of the second movable member;

[0046] - each mobile magnetic dipole has a polar axis oriented orthogonally to its path so that, when the second mobile member moves between two stable extreme positions, at least a repelling magnetic pole of each mobile magnetic dipole is arranged opposite an active magnetic pole of the same polarity of the fixed magnetic dipole;

[0047] - each movable magnetic dipole has a polar axis oriented parallel to its path, the polarity of the movable magnetic dipole being reversed relative to the polarity of the fixed magnetic dipole;

[0048] - At least one of the movable magnetic dipole and the fixed magnetic dipole is in a tubular shape with its main axis coinciding with its polar axis, so that when the second movable member is in an unstable equilibrium intermediate position, the one magnetic dipole concentrically receives the other of the movable magnetic dipole and the fixed magnetic dipole. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Other features and advantages of the present invention will become apparent from the following detailed description which will be understood with reference to the accompanying drawings, in which:

[0050] Figure 1 is a top view schematically showing a molding station loaded into a molding unit implemented according to the teachings of the present invention;

[0051] Figure 2 , 2A , 2B is along Figure 1 A sectional view of section 2-2 in FIG. 2 shows a molding unit of a molding station, and a blowing position and a stowed position of a blowing device;

[0052] Figure 3 is a top view showing a molding unit of a molding station with a mold base in a closed position;

[0053] Figure 4 Similar to Figure 3 , wherein the die holder is in an open position;

[0054] Figure 5 is a side view showing Figure 4 The mold base is shown in an open position, the locking device of the molding unit is in an unlocked position, and the molding unit is equipped with a bistable device, which forces the locking device to move to the locked position or the unlocked position through magnetic interaction between at least one movable dipole and at least one fixed dipole;

[0055] Figure 6 Similar to Figure 5 , wherein the mold base is in a closed position and the locking device is in a locked position;

[0056] Figure 7 is a graph showing the repulsive force exerted by a fixed dipole on a movable dipole of a bistable device as a function of the position of the movable dipole relative to the fixed dipole;

[0057] Figure 8 is an axial cross-section at an enlarged scale, showing Figure 5 The bistable device of the first embodiment is shown in a first stable extreme position corresponding to the locking position of the locking device;

[0058] Fig. 9 Similar to Figure 8 , showing that the bistable device is in a second stable limit position corresponding to the unlocked position of the locking device;

[0059] Fig.10 is along Fig.11 Cross-sectional view of the middle section 10-10;

[0060] Fig.11 Similar to Figure 8 , showing the bistable device in an unstable equilibrium intermediate position corresponding to the intermediate position of the locking device;

[0061] Fig.12 Similar to Figure 8 , showing a bistable device of a second embodiment in an unstable equilibrium position;

[0062] Fig.13 is along Fig.12 Cross-section of the middle section 13-13;

[0063] Fig.14 Similar to Fig.12 , showing another embodiment variant of the second embodiment of the bistable device;

[0064] Fig.15 is along Fig.14 Cross-section of the middle section 15-15;

[0065] Fig.16 Similar to Figure 8 , showing a third embodiment of the bistable device, the bistable device is in a first stable limit position corresponding to the locking position of the locking device;

[0066] Fig.17 Similar to Fig.16 , wherein the bistable device is in a second stable extreme position corresponding to the unlocked position of the locking device;

[0067] Fig.18 is along Fig.17 Cross-section of the middle section 18-18;

[0068] Fig.19is a front view showing a molded unit having a bistable device implemented according to a fourth embodiment of the present invention, the bistable device being in a first stable extreme position corresponding to the locking position of the locking device;

[0069] Fig. 20 Similar to Fig.19 , wherein the bistable device is in a second stable extreme position corresponding to the unlocked position of the locking device;

[0070] Fig.21 is a cross-sectional view along the section 21-21 in 19, showing the position of the movable dipole relative to the fixed dipole in the first stable limit position;

[0071] Fig. 22 is along Fig. 20 The cross-sectional view along section 22-22 shows the position of the movable dipole relative to the fixed dipole in the second stable extreme position. DETAILED DESCRIPTION

[0072] In the following description, components having the same structure or similar function will be denoted by the same reference numerals.

[0073] In the following, the following directions will be used as local geometric coordinates for each molding unit without limitation:

[0074] - a longitudinal direction L, oriented from rear to front, orthogonal to the engaging surface of the mold in the engaged position;

[0075] - vertical direction V, oriented from bottom to top parallel to the mold base hinge axis;

[0076] - Transverse direction T, oriented from left to right parallel to the engaging surface of the mold in the engaged position.

[0077] Figure 1 Schematically shown in the figure is a forming station 10 for forming containers of thermoplastic material, in particular PET (polyethylene terephthalate) containers, by blowing hot preforms. The forming station 10 is intended to be a component of a large-scale container manufacturing plant. Such a plant, for example, has a cold preform heating station in addition to the forming station 10.

[0078] The forming station 10 has a turntable 12 which is mounted rotatably about a vertical axis A on a base 14 fixed relative to the ground. The turntable 12 is here driven by a motor (not shown) to rotate continuously in a counterclockwise direction as indicated by the arrow F1. The motor rotates at a very high speed so that the forming station can produce at least about 2500 containers per hour.

[0079] A plurality of molding units 18 are supported by the turntable 12. The molding units 18 are evenly distributed around the periphery of the turntable 12. Each molding unit 18 is provided with a separate container molding.

[0080] Here, each molding unit 18 is supported by a bracket 20 fixed to the turntable 12, as shown in FIG. Figure 2 shown.

[0081] The support 20 carries a blowing device 21 .

[0082] A first embodiment according to the invention will be described for a blowing station, but the invention is applicable to all blowing devices.

[0083] like Figure 2 As shown, each support 20 has a blowing device 21, also called a blowpipe. The blowing device 21 is particularly movable in translation relative to the support 20 between two extreme stable positions: the blowing position (e.g. Figure 2B As shown), in the blowing position, the blowing device abuts against the upper surface of the mold to supply air to the preform; the retracted position (as shown Figure 2A ), allowing the introduction of preforms or the removal of containers. The blowing device 21 is connected to the support 20, in particular by a linear guide. The movement between the support and the blowing device is ensured by a roller 23 and a cam 25 mechanism.

[0084] To ensure that the blowing device 21 is accurately positioned in the vertical direction, the bistable device 62 has:

[0085] a first member 64 fixed relative to the support 20,

[0086] The second movable member 66 can move between two stable limit positions P1 and P2 on both sides of the unstable equilibrium intermediate position P0, and is connected to the blowing device 21. The second movable member is movably connected to the blowing device 21. The movable member 66 interacts with the fixed member 64 to force the blowing device 21 to move to the blowing position or the stowed position corresponding to each stable limit position P1 and P2.

[0087] The movable component 66 has a first magnetic dipole called the movable magnetic dipole 68, and the fixed component 64 has at least one second magnetic dipole called the fixed magnetic dipole 70, which remotely applies a magnetic force Fm to the movable magnetic dipole 68 to force the movable component 66 to move to one or the other of the two stable extreme positions P1 and P2, regardless of the position of the movable component between its two stable extreme positions P1 and P2.

[0088] Each molding unit 18 has two mold carriers 22, 24, which are movably mounted on the turntable 12. Here, the two mold carriers 22, 24 are mounted in particular on an associated support 20. The molding units 18 are all identical.

[0089] The second embodiment according to the invention will be described for a blowing station, the invention being applicable to all molding units.

[0090] Each mold base 22, 24 is used to receive a mold part 26, 28, such as Figure 3 and 4 As shown. In practice, a mold has at least two semi-cylindrical parts 26, 28, each of which has a cylindrical vertical outer surface 30 intended to face the relative mold base 22, 24 and a flat vertical inner surface 32 having a half-cavity of the container to be molded. When the two mold parts 26, 28 are joined by their inner surfaces 32, the two mold parts thus define a mold cavity forming the cavity of the container to be molded. This mold cavity is opened vertically upwards by a passage 34 for the neck of the container or preform.

[0091] The mold bases 22, 24 are mounted on the turntable 12 so as to be movable between an open position and a closed position. Figure 4 As shown, in the open position, the two mold parts 26, 28 are separated from each other, as shown in FIG. Figure 3 As shown, in the closed position, the two mold portions 26 , 28 are joined by their inner surfaces 32 .

[0092] To ensure that the inner surfaces 32 of the two mold parts 26, 28 engage correctly during the molding operation, it is known to interpose a compensation chamber 35 between the outer surface of at least one mold part 26 and its mold base 22. The mold part 26 is mounted so as to be able to slide with a small stroke between a position retracted toward the mold base 22 and an extended position extending in the direction of the other mold part 28. During the blowing operation, the compensation chamber 35 is supplied with a pressurized pressure fluid in order to push the mold part 26 into its extended position.

[0093] Here, the mold carriers 22, 24 are mounted so as to be pivotable relative to each other about a hinge 36 having a vertical axis B. Thus, each mold carrier 22, 24 has a vertical free edge 38, 40 opposite the hinge 36. Figure 4 As shown, the two free edges 38, 40 are separated in the open position of the mold bases 22, 24, as shown in FIG. Figure 3 As shown, they are engaged in the closed position of the mold carriers 22, 24.

[0094] The hinge 36 is arranged on the side of the rotation axis A of the turntable 12 , while the free edges 38 , 40 are arranged laterally outwardly of the turntable 12 .

[0095] The mold bases 22, 24 are automatically controlled between their closed position and their extreme open position by mechanical control elements, such as cams. The control elements are well known and are not the object of the present invention. Therefore, they will not be described in detail later.

[0096] To ensure that the mold bases 22, 24 remain in their closed position during the blowing operation, the mold bases are provided with locking means 42 which lock the mold bases 22, 24 in the closed position.

[0097] The locking device 42 for locking the mold bases 22 and 24 in the closed position comprises at least one locking member 52 which can be movably mounted on the first mold base, in this case the mold base 22 and 24. Figures 3 to 6 On the right mold base 24 shown on the right side. The locking member 52 is installed to be movable between the following positions:

[0098] - Locking position, in the locking position, the locking piece and the second mold base are Figures 3 to 6 At least one locking surface 45 of the left mold base 22 shown on the left cooperates to prevent the mold bases 22, 24 from opening when they are in the closed position; - and an unlocked position, in which the locking member 52 is retracted relative to the locking surface 45 to allow the mold bases 22, 24 to open.

[0099] exist Figure 5 and 6 In the first embodiment of the present invention shown, the locking member 52 is mounted so as to be slidable relative to the right mold base 24 supporting it.

[0100] Here, the locking device 42 has lugs 44, which are arranged on the free edge of one of the mold bases, here on the free edge 38 of the left mold base 22, and protrude outward. These lugs 44 extend in a horizontal plane and are arranged one above the other in the vertical direction along the free edge 38. Each lug is provided with a socket. 46 is vertically penetrated, and the inner surface of the socket forms the locking surface 45 of the left mold base 22. Here, these sockets 46 are vertically coaxial. Here, the number of lugs 44 is three.

[0101] The right mold base 24 is provided with U-shaped clamps 48. Each clamp 48 has two wings extending parallel to each other in a horizontal plane. The wings of the clamp are penetrated vertically by guide holes 50. The guide holes 50 are vertically coaxial. The clamps 48 are arranged one above the other vertically along the free edge 40 of the right mold base 24. The right mold base 24 has the same number of clamps 48 as the lugs 44 of the left mold base 22.

[0102] like Figure 6 As shown, when the mold bases 22, 24 are in their closed position, each lug 44 is received between the two wings of the corresponding clamp 48. Each socket 46 coincides with a guide hole 50 of the clamp 48.

[0103] The locking device 42 also has a locking member 52 formed by a finger with a vertical axis, which is supported by the right mold base 24. The locking member 52 is guided to slide vertically in the guide hole 50 of the clamp 48. The right mold base 24 has the same number of locking members 52 as the clamp 48.

[0104] Each locking member 52 is mounted on the right mold base 24 so as to be able to slide vertically between a lower limit unlocking position and an upper limit locking position. In the lower limit unlocking position, the upper free end of the locking member 52 is substantially arranged at the same height as the lower wing portion of the associated clamp 48, such as Figure 5 As shown, in the upper limit locking position, the locking member 52 passes through the guide holes 50 of the lower wing and the upper wing of the relevant clamp 48, as shown in FIG. Figure 6 shown.

[0105] like Figure 6 As shown, when the mold bases 22, 24 are in their closed position, each locking member 52 thus passes through the socket 46 of the lug 44 received in the associated clamp 48. Thus, each locking member 52 cooperates with the inner surface 45 of the socket 46 to prevent the mold bases 22, 24 from opening.

[0106] In the following, the mold bases 22, 24 are considered to be in the closed position only when the guide holes 50 overlap the sockets 46 sufficiently to allow the locking member 52 to slide through the associated sockets 46 to its locked position. Figure 3 and 6 In any other position than the closed position thus defined, the mold carriers 22, 24 are considered to be in the open position.

[0107] The locking device 42 is adapted to be automatically controlled between its unlocked state and locked state, for example by a cam. To this end, all locking members 52 are fixed to a common vertical operating rod 54, which is vertically slidably mounted on the right mold base 24. Here, the rod 54 is offset longitudinally relative to the locking members 52. The locking members 52 are fixed to the operating rod 54 by a horizontal fixing rod 55.

[0108] The operating rod 54 is guided to slide in the base of each clamp 48. Therefore, all the locking elements 52 slide together with the operating rod 54. The sliding of the locking elements 52 is controlled by a cam follower, here a roller 56, which is arranged at the lower end of the operating rod 54 and rolls on an upward locking cam track 58, which is fixed relative to the base 14 of the turntable 12. Therefore, when the roller 56 reaches the upper section of the locking cam track 58, the operating rod 54 slides upward, as shown in FIG. Figure 6 As shown by the arrow F2 in the figure, the locking member 52 is controlled in its locking position.

[0109] The locking member 52 is, for example, controlled by the second unlocking cam to the unlocking position of the locking member. Therefore, the roller 56 can control the locking member 52 to its unlocking position again by cooperating with the downwardly directed unlocking cam path 60, such as Figure 6 Indicated by the dashed line.

[0110] In a variant not shown, the locking element may be controlled between its locked state and its unlocked state by any other known means, for example by an electric motor.

[0111] In order to prevent the locking element 52 from being in an intermediate position between its locked and unlocked positions, the molding unit 18 is provided with a bistable device 62 having:

[0112] - a first member 64 fixed relative to the right mold base 24, which carries the locking element 52; and

[0113] - A second movable component 66 is mounted on the right mold base 24 so as to be movable along a certain stroke and is movably connected to the locking member 52 .

[0114] The movable member 66 has at least one first magnetic dipole referred to as a movable magnetic dipole 68 , and the fixed member 64 has at least one second magnetic dipole referred to as a fixed magnetic dipole 70 .

[0115] The movable magnetic dipole 68 and the fixed magnetic dipole 70 interact together to force the movable member 66 to move to two stable limit positions P1 and P2, which are located at both ends of its travel on both sides of the unstable equilibrium intermediate position P0. Therefore, the movable member 66 can force the locking device 42 to move to the locking position corresponding to the first stable limit position P1 of the movable member 66, or to the unlocking position corresponding to the second stable limit position P2 of the movable member 66.

[0116] To this end, at least one magnetic dipole 68, 70 remotely exerts a magnetic force Fm on the other magnetic dipole 70, 68 to force the movable member 66 to move toward one or the other of its two stable extreme positions P1, P2, whatever its position along its travel.

[0117] In particular, when the movable member 66 is located between its unstable equilibrium intermediate position P0 and its first stable limit position P1, the movable member is forced to move toward the first stable limit position P1, and when the movable member 66 is located between its unstable equilibrium intermediate position P0 and its second stable limit position P2, the movable member is forced to move toward the second stable limit position P2. When the movable member 66 is in the unstable equilibrium intermediate position P0, the movable member is immediately forced to randomly move toward one or the other of its stable limit positions P1 and P2.

[0118] Each of the two magnetic dipoles 68, 70 emits a magnetic field. In particular, each magnetic dipole 68, 70 always emits a magnetic field at least during the period when the molding unit 18 is in the container production process. Here, each magnetic dipole 68, 70 is formed by a permanent magnet or by a stack of permanent magnets. In fact, it is known that a plurality of permanent magnets stacked and engaged with each other by magnetic attraction act together as a single magnetic dipole.

[0119] Each permanent magnet is made of a material compatible with the use temperature of the molded unit 18, which can be up to about 100° C. Each permanent magnet is, for example, based on neodymium (Nd), for example, a magnet made of a neodymium iron boron alloy (NdFeB). In a variant, each permanent magnet is, for example, based on samarium (Sm), for example, a magnet made of a samarium cobalt alloy (SmCo).

[0120] In a variant of the invention not shown, at least one magnetic dipole is formed by an electromagnet. In this case, when the molding unit 18 is operating to produce a container, the electromagnet is powered to generate a permanent fixed magnetic field, regardless of the position of the mobile member 66.

[0121] In the embodiment of the invention shown in the drawings, here, each fixed magnetic dipole 70 acts on each movable magnetic dipole 68 by magnetic repulsion by applying a repulsive force Fm to each movable magnetic dipole, so as to push the movable member 66 to one or the other of its two stable extreme positions P1, P2.

[0122] The repulsive force exerted by all fixed magnetic dipoles 70 on all movable magnetic dipoles 68 is sufficient to keep the locking member 52 in a locked position or an unlocked position corresponding to one or the other of the stable extreme positions P1, P2 of the movable component 66, especially when the control roller 56 does not contact one or the other of the locking or unlocking cams 58, 60.

[0123] To avoid interference with the magnetic field emitted by the magnetic dipoles 68, 70, the components of the movable member 66 and the fixed member 64 are made of non-magnetic materials, that is, such non-magnetic materials have negligible magnetic susceptibility, such as aluminum, copper or plastic.

[0124] like Figure 7 As shown, the repulsive force Fm varies with the position of the movable member 66 between its two stable limit positions P1 and P2. Here, the force Fm is shown in its algebraic value, and when the force pushes the movable member 66 toward the first stable limit position P1, the force is positive, and when the force pushes the movable member 66 toward the second stable limit position P2, the force is negative. When the movable member 66 is in the unstable equilibrium position P0, the repulsive force Fm is zero.

[0125] The magnetic dipoles 68 and 70 are arranged so that the repulsive force Fm has a slope connecting two extreme values ​​Max1 and Max2 of opposite signs as the position of the movable member 66 changes. Here, the magnetic dipoles 68 and 70 are designed and arranged so that at each of the two stable extreme positions P1 and P2, the absolute value of the force Fm applied to all active magnetic dipoles 68 is between 30 Newtons and 100 Newtons, for example, approximately equal to 60 Newtons.

[0126] exist Figure 7 In the example, the magnetic dipoles 68 , 70 are designed and arranged so that in their first extreme stability position P1 , respectively in their second extreme stability position P2 , the absolute value of the force Fm exerted on all active magnetic dipoles 68 is equal to their local extreme value Max1 , respectively Max2 .

[0127] exist Figure 5 , 6 In the first embodiment shown in Figures 8 to 11, the movable member 66 is mounted to slide vertically relative to the fixed member 64. In particular, the movable member 66 is integrally connected to the locking member 52. Here, the movable member 66 is formed by a rod with a vertical axis C, for example, fixed to the operating rod 54 by a crossbar 55. The fixed member 64 has a guide bearing 72 for guiding the sliding movement of the movable member 66.

[0128] like Figure 5 and 6 As shown, the movement of the locking member 52 is limited by the first mechanical stopper 74 in its locking position and by the second mechanical stopper 76 in its unlocking position. In a non-limiting manner, the mechanical stops 74 and 76 are formed by pins fixed to the right mold base 24. The movable member 66 is integrally connected to the locking member 52 for movement, and therefore, the movement of the movable member is also limited by the first mechanical stopper 74 to the first stable limit position P1 of its upper portion corresponding to the locking position, as shown in FIG. Figure 8 As shown, and is limited by the second mechanical stopper 76 to the second stable limit position P2 of its lower portion corresponding to the unlocked position, as shown Fig. 9 shown.

[0129] Here, the fixing member 64 has a single magnetic dipole 70 . Figures 8 to 11 The fixed magnetic dipole 70 shown has a polar axis M1 which is oriented parallel to the path of the movable member 66. The polar axis M1 is thus oriented vertically. In particular, the fixed magnetic dipole 70 is formed by at least one axially magnetized annular magnet 78. The polar axis M1 of the annular magnet 78 thus coincides with its main axis.

[0130] Therefore, each annular magnet 78 has a central hole 80 of circular profile in cross section, and the polar axis M1 passes through the middle of the central hole, as shown in FIG. Fig.10 The upper annular surface 82 of each annular magnet 78 forms a first magnetic pole having a first polarity, such as the north pole N. Figures 8 to 11 As shown, the lower annular surface 84 of each annular magnet 78 forms a second magnetic pole with opposite polarity, such as a south pole S. In the example, the fixed magnetic dipole 70 is formed by a stack of a plurality of annular magnets 78, and here by a stack of four identical annular magnets 78. In particular, the fixed magnetic dipole 70 is arranged so that its polar axis M1 is coaxial with the axis C of the movable member 66.

[0131] Here, the movable member 66 has a single magnetic dipole 68. The movable magnetic dipole 68 has a polar axis M2 which is parallel to its path, here oriented vertically. In particular, the movable magnetic dipole 68 is formed by at least one axially magnetized annular magnet 86. Its polar axis M2 coincides with its main axis, as shown in FIG. Fig.10 As shown. Therefore, each annular magnet 86 has a central hole 88 with a circular profile in cross section, and the polar axis M2 passes through the middle of the central hole. The upper annular surface 90 of each annular magnet 86 forms a first magnetic pole with a first polarity, such as a south pole S, as shown in FIG. Figures 7 to 10 As shown, the lower annular surface 92 of each annular magnet 86 forms a second magnetic pole with opposite polarity, for example the north pole N. In the example, the movable magnetic dipole 68 is formed in particular by a stack of a plurality of annular magnets 86 , here four identical annular magnets 86 .

[0132] The polar axis M2 of the movable magnetic dipole 68 is arranged coaxially with the polar axis M1 of the fixed magnetic dipole 70 so that the radial force applied to the movable magnetic dipole 68 by the fixed magnetic dipole 70 with respect to the axis C of the movable member 66 can be substantially eliminated.

[0133] Here, the movable member 66 is formed by a rod implemented in two sections, where the annular magnet 86 of the movable magnetic dipole 68 is fitted around the terminal end of the first section, and the first section is then fixed to the second section, for example by screwing, so that the annular magnet 86 is vertically fixed to the movable member 66 by the vertical fastening between the two sections. The annular magnet 86 forming the movable magnetic dipole 68 is slidably received in the central hole 80 of the annular magnet 78 of the fixed magnetic dipole 70, as shown in FIG. Figures 8 to 11 As shown. Fig.11 In the unstable equilibrium position P0 of the movable member 66 shown, the movable magnetic dipole 68 is concentrically received in the central hole 80 of the fixed magnetic dipole 70, and an annular air gap g is radially retained between the outer cylindrical surface of the movable magnetic dipole 68 and the inner cylindrical surface of the fixed magnetic dipole 70.

[0134] The polarity of the movable magnetic dipole 68 formed by the annular magnet 86 is reversed relative to the polarity of the fixed magnetic dipole 70 formed by the annular magnet 78 .

[0135] When the molding unit 18 is working, Figure 6 Starting from the locked position shown, the movable member 66 is in Figure 8Its first stable limit position P1 is shown, in which the fixed magnetic dipole 70 applies an upwardly oriented magnetic force Fm, which is here equal to its local extreme value Max1. More precisely, the lower magnetic pole of the movable magnetic dipole 68, here the north pole N, is pushed upward by the upper magnetic pole of the fixed magnetic dipole 70 with the same polarity. Therefore, the movable member 66 is pushed against the first mechanical stop 74 with a force sufficient to keep the locking member 52 in its locked position. When the roller 56 rolls on the descending slope of the unlocking cam track 60, the roller applies a vertically downwardly oriented control force to the movable member 66, which exceeds the magnetic force Fm of the bistable device 62. Therefore, the movable member 66 slides vertically downward against the action of the magnetic force Fm until it reaches Fig.11 The unstable equilibrium position P0 is shown in FIG. In this way, the strength of the magnetic force Fm decreases uniformly, as shown in FIG. Figure 7 shown.

[0136] When the movable member 66 exceeds its unstable equilibrium position P0 and approaches its second equilibrium position P2, the force Fm increases and is oriented downward to push the movable member 66 toward its second stable limit position P2, where the movable member is stopped by the second mechanical stopper 76. Figure 5 and 9 shown.

[0137] When the movable member 66 reaches its second stable limit position P2, it is pushed against the second mechanical stopper 76 by the magnetic force Fm with a strength sufficient to keep the locking member 52 in its unlocked position.

[0138] In order to control the locking member 52 to move to its locking position again, the roller 56 rolls on the upward slope of the locking cam track 58, exerting a control force on the movable member 66 that is vertically oriented upward and exceeds the magnetic force Fm of the bistable device 62. Therefore, the movable member 66 slides vertically upward against the effect of the magnetic force Fm until it reaches the position of the movable member 66. Fig.11 The unstable equilibrium position P0 is shown in FIG. In this way, the strength of the magnetic force Fm decreases uniformly, as shown in FIG. Figure 7 shown.

[0139] When the movable member 66 exceeds its unstable equilibrium position P0 and approaches its first equilibrium position P1, the force Fm increases and is directed upward to push the movable member 66 to its first stable limit position P1 corresponding to the locking position of the locking member 52, and the movable member is stopped at the first stable limit position by the first mechanical stopper 74, as shown in FIG. Figure 6 and 8 shown.

[0140] Fig.12 and 13A second embodiment of the present invention is shown in FIG. The bistable device 62 is similar to the bistable device described in the first embodiment of the present invention. Only the differences from the previous embodiment will be described in detail below, and the other structural parts are the same or have similar operation.

[0141] Here, the fixed member 64 has at least one magnetic dipole 70 , the polar axis M1 of which is oriented orthogonally to the path of the movable member 66 . Here, the fixed magnetic dipole 70 is formed by a permanent magnet 78 .

[0142] exist Fig.12 and 13 In the example of FIG. 6 , the fixed member 64 has two fixed magnetic dipoles 70A, 70B, which are symmetrically arranged with respect to the sliding axis C of the movable member 66. Therefore, the polar axes M1 of each fixed magnetic dipole 70A, 70B are arranged coaxially with each other and radially with respect to the sliding axis C. The movable magnetic dipole 68 is used to pass between the fixed magnetic dipoles 70.

[0143] Thus, each fixed magnetic dipole 70A, 70B has a magnetic pole, referred to as an active magnetic pole, which is arranged facing the path of the mobile magnetic dipole 68 .

[0144] In the example, each fixed magnetic dipole 70A, 70B is formed by a permanent magnet 78. As shown on the left side of the figure, the active magnetic pole of one of the fixed magnetic dipoles 70A is formed by a north pole N, while the active magnetic pole of the other fixed magnetic dipole 70B is formed by a south pole S.

[0145] Here, the movable member 66 has a single movable magnetic dipole 68. The movable magnetic dipole 68 is formed by a permanent magnet 86. The movable magnetic dipole 68 has a polar axis M2 oriented orthogonally to its path, here radially with respect to the sliding axis C. Fig.12 and 13 In the example of FIG. 7 , the polar axis M2 is oriented parallel to the polar axis M1 of the fixed magnetic dipole 70 .

[0146] Therefore, the movable magnetic dipole 68 has two magnetic poles, namely repelling magnetic poles, each of which is arranged to face the active magnetic pole of each fixed magnetic dipole 70A, 70B with the same polarity when the movable member 66 is in its unstable equilibrium position P0. The repelling magnetic poles are arranged symmetrically with respect to the sliding axis C. In the unstable equilibrium position P0, the polar axes M1, M2 of the fixed magnetic dipoles 70A, 70B and the movable magnetic dipole 68 are aligned here.

[0147] An air gap g is radially retained between each repelling pole of the movable magnetic dipole 68 and the active pole of the associated fixed magnetic dipole 70A, 70B to allow the movable magnetic dipole 68 to pass between the fixed magnetic dipoles 70A, 70B without contact. The strength of the magnetic force Fm can be adjusted by acting on the air gap g.

[0148] In order for the bistable device 62 to work properly, the movable magnetic dipole 68 must maintain a fixed angular position relative to the fixed magnetic dipoles 70A, 70B so that the polar axes M1 and M2 remain parallel to each other.

[0149] The operation of the bistable device 62 according to the second embodiment is the same as that of the first embodiment, and therefore will not be described in detail below.

[0150] exist Fig.14 and 15 In the variant of this second embodiment shown, the fixed member 64 has more than two, here four, magnetic dipoles 70A, 70B, 70C, 70D, which are evenly distributed around the sliding axis C of the movable member 66 to form a ring. Therefore, the polar axis M1 of each fixed magnetic dipole 70A, 70B, 70C, 70D is arranged radially with respect to the sliding axis C of the movable member 66.

[0151] Thus, each fixed magnetic dipole 70A, 70B, 70C, 70D has a magnetic pole, namely an active magnetic pole, which is arranged to face the path of the associated movable magnetic dipole 68A, 68B, 68C, 68D.

[0152] Here too, the movable member 66 has a plurality of movable magnetic dipoles 68A, 68B, 68C, 68D, which are uniformly arranged around the sliding axis C. The movable magnetic dipoles 68A, 68B, 68C, 68D are used to pass between the fixed magnetic dipoles 70A, 70B, 70C, 70D. Here, each of the movable magnetic dipoles 68A, 68B, 68C, 68D is formed by a permanent magnet 86. Each movable magnetic dipole 68A, 68B, 68C, 68D has a polar axis M2, which is oriented orthogonal to its path, and here is oriented radially relative to the sliding axis C. Therefore, in Fig.14 and 15 In the example of FIG. 7 , the polar axis M2 is oriented parallel to the polar axis M1 of the fixed magnetic dipoles 70A, 70B, 70C, 70D.

[0153] Advantageously, all active magnetic poles of the fixed magnetic dipoles 70A, 70B, 70C, 70D here have the same polarity. For example, it concerns the north pole N. In this case, the movable member 66 has the same number of movable magnetic dipoles 68A, 68B, 68C, 68D as the fixed magnetic dipoles 70A, 70B, 70C, 70D that the fixed member 64 has. Therefore, each movable magnetic dipole 68A, 68B, 68C, 68D has a magnetic pole, namely a repelling magnetic pole, which is arranged to face the active magnetic pole of the same polarity of the associated fixed magnetic dipole 70A, 70B, 70C, 70D when the movable member 66 is in its unstable equilibrium position P0.

[0154] In this unstable equilibrium position P0, the polar axes M1, M2 of the associated two fixed and active magnetic dipoles 68, 70 are aligned. An air gap g remains between the active magnetic pole and the associated repelling magnetic pole.

[0155] In the first stable equilibrium limit position P1 , the active magnetic dipole 68 is arranged above its unstable equilibrium position P0 , and in the second stable equilibrium limit position P2 , the active magnetic dipole 68 is arranged below its unstable equilibrium position P0 .

[0156] With this configuration, it is easier to properly orient the movable member 66 about the sliding axis C so that each repelling pole of the movable magnetic dipoles 68A, 68B, 68C, 68D faces an associated active pole of the fixed magnetic dipoles 70A, 70B, 70C, 70D.

[0157] Figures 16 to 18 2 shows a third embodiment of the present invention, which is applied to the molding unit 18 described in the first embodiment. Only the differences from the first embodiment will be described below.

[0158] Here, the fixed member 64 has a plurality of magnetic dipoles, here sixteen magnetic dipoles 70, which are evenly distributed in a ring around the sliding axis C of the movable member 66. The polar axis M1 of each fixed magnetic dipole 70 is arranged radially relative to the sliding axis C of the movable member 66. In this way, each fixed magnetic dipole 70 has an active magnetic pole facing the sliding axis C. The active magnetic poles all have the same polarity.

[0159] Here, the mobile component 66 has a single magnetic dipole 68. The mobile magnetic dipole 68 has a polar axis M2 which is parallel to its path, here oriented vertically. Here, the mobile magnetic dipole 68 is implemented in the same way as already described in the first embodiment.

[0160] The movable magnetic dipole 68 is used to pass between the active magnetic poles of the fixed magnetic dipole 70. One of the magnetic poles of the movable magnetic dipole 68, hereinafter referred to as the "repulsive magnetic pole", has the same polarity as the active magnetic pole of the fixed magnetic dipole 70. Here, the active magnetic pole and the repulsive magnetic pole are the south pole S. When the movable member 66 is in an intermediate position between its two stable extreme positions P1 and P2, the repulsive magnetic pole of the movable magnetic dipole 68 faces the active magnetic pole of the fixed magnetic dipole 70. In a non-limiting manner, here, the repulsive magnetic pole is arranged at the lower part of the movable magnetic dipole 68.

[0161] As in the other embodiments, an air gap g remains radially between the movable magnetic dipole 68 and each active magnetic pole of the fixed magnetic dipole 70 .

[0162] When the molding unit 18 is working, Figure 6 Starting from the locked position shown, the movable member 66 is in Fig.16 The movable member 66 is shown in its first stable limit position P1, in which the fixed magnetic dipole 70 exerts an upward magnetic force Fm, which is here equal to its local extreme value Max1. More precisely, the lower repelling magnetic pole of the movable magnetic dipole 68, here the north pole S, is pushed upward by the active magnetic pole of the fixed magnetic dipole 70 with the same polarity. Therefore, the movable member 66 is pushed against the first mechanical stop 74 with a force sufficient to keep the locking member 52 in its locked position. In this first stable limit position P1, the movable magnetic dipole 68 is clearly arranged above the fixed magnetic dipole 70.

[0163] When the roller 56 rolls on the descending slope of the unlocking cam track 60, the roller applies a control force directed vertically downward to the movable member 66, which exceeds the magnetic force Fm of the bistable device 62. Therefore, the movable member 66 slides vertically downward against the effect of the magnetic force Fm until it reaches its unstable equilibrium position P0. In this way, the strength of the magnetic force Fm decreases uniformly.

[0164] When the movable member 66 exceeds its unstable equilibrium position P0 and approaches its second equilibrium position P2 , the force Fm increases and is directed downward to push the movable member 66 toward its second stable limit position P2 , where it is stopped by the second mechanical stopper 76 .

[0165] When the movable member 66 reaches its second stable limit position P2, the movable member is pushed against the second mechanical stopper 76 by the magnetic force Fm with a strength sufficient to keep the locking member 52 in its unlocked position. Here, the magnetic force Fm is composed of the repulsive force exerted by the active magnetic pole of the fixed magnetic dipole 70 on the repulsive magnetic pole of the movable magnetic dipole 68 plus the attractive force exerted by the active magnetic pole of the fixed magnetic dipole 70 on the magnetic pole with the opposite polarity of the movable magnetic dipole 68, here, the north pole N. In this second stable limit position P2, the magnetic pole of the movable magnetic dipole 68 opposite to the repulsive magnetic pole is arranged substantially at the same height as the fixed magnetic dipole 70.

[0166] In order to control the locking member 52 to move to its locking position again, the roller 56 rolls on the upward slope of the locking cam track 58, exerting a vertically upward control force on the movable member 66, which exceeds the magnetic force Fm of the bistable device 62. Therefore, the movable member 66 resists the action of the magnetic force Fm and slides vertically upward until it reaches its unstable equilibrium position P0, as shown in FIG. Fig. 9 As shown. In this way, the strength of the magnetic force Fm decreases evenly.

[0167] When the movable member 66 exceeds its unstable equilibrium position P0 and approaches its first equilibrium position P1, the magnetic force Fm increases and is oriented upward to push the movable member 66 to its first stable limit position P1 corresponding to the locking position of the locking member 52, and it is stopped at this position by the first mechanical stopper 74.

[0168] according to Figures 19 to 22 In the fourth embodiment of the invention shown, the mobile member 66 is mounted on the right mold base 24 so as to be able to pivot about the pivot axis X between its two stable positions.

[0169] In the example of the drawings, the locking member 52 is also mounted on the right mold base 24 to pivot between its locking position and its unlocking position. The locking member 52 and the movable member 66 are rotatably connected by a connecting rod 94, which has the same function as the control rod 54 of the first embodiment of the present invention.

[0170] Here, the movable magnetic dipole 68 is fixed to the movable member 66 eccentrically with respect to the pivot axis X, while the fixed magnetic dipole 70 is fixed to the right mold base 24 .

[0171] The fixed magnetic dipole 70 has a polar axis M1 oriented parallel to the pivot axis X of the movable member 66 . Here the active magnetic pole of the north pole N is directed towards the path of the movable magnetic dipole 68 .

[0172] The active magnetic dipole 68 has a polar axis M2 also oriented parallel to the pivot axis X of the active member 66. When the active member 66 is in its unstable equilibrium position P0, a repelling magnetic pole having the same polarity as the active magnetic pole of the fixed magnetic dipole 70 is arranged facing the active magnetic pole.

[0173] Therefore, if Fig.21 and 22 As shown, the fixed magnetic dipole 70 exerts a repulsive magnetic force Fm on the movable magnetic dipole 68 to push the movable member 66 toward the positions shown in FIG. Fig.21 and 22 Each of its stable limit positions P1 or P2.

[0174] The operation of the bistable device 62 implemented according to this fourth embodiment is similar to the operation of the bistable device 62 implemented according to the first embodiment of the present invention.

[0175] The bistable device 62 implemented according to the teachings of the present invention allows the movable member 66 to interact with the fixed member 64 without contact. This avoids wear on the movable parts of the device and reduces maintenance operations of the bistable device 62.

[0176] In addition, the design, manufacturing and maintenance costs of the bistable device 62 designed in this way are not high.

[0177] It is understood that the bistable device 62 implemented according to any of the first three embodiments may be adapted to the bistable device 62 as described in the fourth embodiment and Fig.19 and 20 The molding unit 18 is shown.

Claims

1. A thermoplastic material container forming station (10), comprising: - a container molding unit (18) for molding a container by blowing a preform; - a bracket (20); a blowing device (21) movable in translation relative to the support (20) between two stable extreme positions: a blowing position in which the blowing device is in contact with the upper surface of the mold to blow the preform; and a stowed position allowing the introduction of a preform or the removal of a container; - a bistable device (62) having: a first fixing member (64) fixed relative to the support (20), a second movable member (66) movable between two stable limit positions P1, P2 located on both sides of the unstable equilibrium intermediate position P0, connected to the blowing device (21), the second movable member being movably connected to the blowing device (21), the second movable member (66) interacting with the first fixed member (64) to force the blowing device (21) to move to a blowing position or a stowed position corresponding to each stable limit position P1, P2; It is characterized in that The second movable member (66) has a first magnetic dipole called a movable magnetic dipole (68), and the first fixed member (64) has at least one second magnetic dipole called a fixed magnetic dipole (70), and the fixed magnetic dipole (70) remotely applies a repulsive magnetic force Fm to the movable magnetic dipole (68) to force the second movable member (66) to move to one or the other of the two stable limit positions P1, P2, regardless of the position of the second movable member between the two stable limit positions P1, P2.

2. A thermoplastic material container forming station (10), comprising: - a container molding unit (18) for molding a container by blowing a preform; - a first mold base (22) and a second mold base (24), each for supporting a portion of the mold, the first mold base (22) and the second mold base (24) being mounted to be movable relative to each other between a mutually separated open position and a joined closed position; - a locking device (42) for locking the first mold base (22) and the second mold base (24) in a closed position, the locking device having at least one locking member (52) mounted on the second mold base (24) so ​​as to be movable between a locked position and an unlocked position, wherein in the locked position, the locking member cooperates with at least one locking surface (45) of the first mold base (22) to prevent the first mold base (22) and the second mold base (24) from opening, and in the unlocked position, the locking member (52) is retracted relative to the locking surface (45) to allow the first mold base (22) and the second mold base (24) to open; - a bistable device (62) having: a first fixing member (64) fixed relative to the second mold base (24), - a second movable member (66) mounted on the second mold base (24) so ​​as to be movable between two stable limit positions P1, P2 located on both sides of the unstable equilibrium intermediate position P0, the second movable member being movably connected to the locking member (52), the second movable member (66) interacting with the first fixed member (64) to force the locking device (42) to move to a locking position or an unlocking position corresponding to each stable limit position P1, P2; It is characterized in that The second movable member (66) has a first magnetic dipole called a movable magnetic dipole (68), and the first fixed member (64) has at least one second magnetic dipole called a fixed magnetic dipole (70), and the fixed magnetic dipole (70) remotely applies a repulsive magnetic force Fm to the movable magnetic dipole (68) to force the second movable member (66) to move to one or the other of the two stable limit positions P1, P2, regardless of the position of the second movable member between the two stable limit positions P1, P2.

3. The thermoplastic material container forming station (10) according to claim 2, characterized in that The movement of the second movable member (66) is stopped at two stable limit positions P1, P2 by the relevant mechanical stops (74, 76), and the repulsive magnetic force Fm applied by each fixed magnetic dipole (70) to each movable magnetic dipole (68) is sufficient to keep the locking member (52) in a locked position or an unlocked position corresponding to one or the other of the two stable limit positions P1, P2 of the second movable member (66).

4. Thermoplastic material container forming station (10) according to claim 2 or 3, characterized in that The second movable member (66) is mounted on the second mold base (24) so ​​as to be able to slide along a linear path between two stable limit positions P1 and P2.

5. The thermoplastic material container forming station (10) according to claim 2, characterized in that The second movable member (66) is mounted on the second mold base (24) so ​​as to be pivotable about a pivot axis X between two stable limit positions P1 and P2, and the movable magnetic dipole (68) is eccentrically fixed to the second movable member (66) relative to the pivot axis X.

6. Thermoplastic material container forming station (10) according to claim 1 or 2, characterized in that The fixed magnetic dipole (70) acts on the movable magnetic dipole (68) by magnetic repulsion by applying a repulsive magnetic force Fm to the movable magnetic dipole, so as to push the second movable member (66) to one or the other of the two stable limit positions P1, P2.

7. Thermoplastic material container forming station (10) according to claim 1 or 2, characterized in that Each of the movable magnetic dipole (68) and the fixed magnetic dipole (70) is a permanent magnet that always emits a magnetic field.

8. Thermoplastic material container forming station (10) according to claim 1 or 2, characterized in that The repulsive magnetic force Fm has a slope connecting two extreme values ​​Max1 and Max2 of opposite signs as the position of the second movable member (66) changes, and the at least one fixed magnetic dipole (70) is designed so that at each of the two stable extreme positions P1 and P2, the norm of the repulsive magnetic force Fm applied to the at least one movable magnetic dipole (68) is between 30 Newtons and 100 Newtons.

9. Thermoplastic material container forming station (10) according to claim 1 or 2, characterized in that The movable magnetic dipole (68) and the fixed magnetic dipole (70) are designed so that at each of the two stable extreme positions P1, P2, the norm of the repulsive magnetic force Fm applied to at least one movable magnetic dipole (68) is equal to the local extreme value Max1, Max2.

10. Thermoplastic material container forming station (10) according to claim 1 or 2, characterized in that Each fixed magnetic dipole (70) has a polar axis M1 oriented orthogonal to the path of the first fixed member (64), and a magnetic pole of each fixed magnetic dipole (70), called an active magnetic pole, is arranged to face the path of the active magnetic dipole (68).

11. Thermoplastic material container forming station (10) according to claim 1 or 2, characterized in that The first fixed member (64) has a plurality of fixed magnetic dipoles (70), all of which have active magnetic poles with the same polarity.

12. Thermoplastic material container forming station (10) according to claim 1 or 2, characterized in that Each active magnetic dipole (68) has a polar axis M2 oriented along the path direction, each active magnetic dipole (68) has a magnetic pole called a "repulsive magnetic pole", the polarity of the repulsive magnetic pole is the same as the polarity of the active magnetic pole of the fixed magnetic dipole (70), and when the second active member (66) is in an intermediate position between the two stable extreme positions P1, P2, the repulsive magnetic pole faces the active magnetic pole.

13. Thermoplastic material container forming station (10) according to claim 1 or 2, characterized in that Each fixed magnetic dipole (70) has a polar axis M1 oriented parallel to the path of the second movable member (66).

14. Thermoplastic material container forming station (10) according to claim 1 or 2, characterized in that Each active magnetic dipole (68) has a polar axis M2 oriented orthogonally to the path so that when the second movable member (66) moves between two stable extreme positions P1, P2, at least the repelling magnetic pole of each active magnetic dipole (68) is arranged opposite to the active magnetic pole of the fixed magnetic dipole (70) having the same polarity.

15. Thermoplastic material container forming station (10) according to claim 14, characterized in that Each movable magnetic dipole (68) has a polar axis M2 oriented parallel to the path, and the polarity of the movable magnetic dipole (68) is reversed relative to the polarity of the fixed magnetic dipole (70).

16. Thermoplastic material container forming station (10) according to claim 15, characterized in that At least one of the movable magnetic dipole (68) and the fixed magnetic dipole (70) is in a tubular shape with a main axis coinciding with a corresponding polar axis, so that when the second movable member (66) is in an unstable equilibrium intermediate position, the one magnetic dipole concentrically receives the other of the movable magnetic dipole (68) and the fixed magnetic dipole (70).

17. Thermoplastic material container forming station (10) according to claim 8, characterized in that The at least one fixed magnetic dipole (70) is designed so that, in each of the two stable extreme positions P1, P2, the norm of the repulsive magnetic force Fm exerted on the at least one movable magnetic dipole (68) is equal to 60 Newtons.

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