Actuator with secure trigger

Abstract

The invention relates to an actuator (1) comprising first (2) and second (3) magnetic members spaced apart from each other by a fixed distance (d') along an axis X, the first member (2) comprising two magnets (14) of opposite polarity and the second member comprising a magnet (17), one of the magnets (14) of the first member (2) interacting magnetically with the magnet (17) of the second member (3), the second member (3) being translatably movable along an axis Y perpendicular to the axis X between a stable equilibrium configuration in which the force of attraction between the members is maximum and at least one unstable configuration in which the repulsive force between the members is maximum, the second member (3) being driven towards the stable equilibrium configuration when subjected to an external force (F) applied, an action being triggered when the second member (3) reaches the stable equilibrium configuration after having passed the unstable configuration.

Description

[0001] Description

[0002] Title: Safety-Triggered Actuator

[0003] The present invention relates to securing the triggering of an actuator.

[0004] Actuators are known to trigger an action when subjected to an external force, which can be mechanical, thermal, or electromagnetic in origin. A flow restrictor, a valve, or an electrical circuit switch can be examples of such actuators. However, these actuators generally do not perform a driving action when the external force applied to them exceeds the threshold value for triggering the action. In other words, they do not guarantee that the action they are supposed to perform will actually be carried out.

[0005] Therefore, there is a need to overcome this drawback.

[0006] The invention relates to an actuator comprising first and second magnetic elements spaced apart by a fixed distance along an axis X, the first magnetic element comprising at least two permanent magnets of opposite polarity along axis X and the second magnetic element comprising at least one permanent magnet, at least one of the magnets of the first magnetic element interacting magnetically with the magnet of the second magnetic element in at least one actuator configuration, the second magnetic element being movable in translation relative to the first magnetic element along a translation axis Y perpendicular to axis X between at least one stable equilibrium configuration where the magnetic attraction force between the first and second magnetic elements is maximum and at least one unstable configuration where the magnetic repulsion force between the first and second magnetic elements is maximum.

[0007] The actuator T is configured so that the second magnetic element is driven in translation along the translation axis Y towards the stable equilibrium configuration under the effect of an external force applied to the actuator T, and to trigger an action when the second magnetic element reaches the stable equilibrium configuration after passing through the unstable configuration in its movement. It also relates to a method for triggering an action, comprising:

[0008] - the application of an external force on the actuator according to the invention to drive the second magnetic element in translation along the Y axis relative to the first magnetic element and to transmit, the intensity of the external force being sufficient for the second magnetic element to reach the stable equilibrium configuration after having passed through the unstable configuration in its movement, and

[0009] - triggering an action when the second magnetic element is in the stable equilibrium configuration.

[0010] When an external force is applied to the actuator, for example, due to acceleration or impact, the second magnetic element is displaced towards a stable equilibrium configuration. It is then subjected to a repulsive force that increases as it approaches the magnet of the first magnetic element of the same polarity along the Y-axis. If the energy imparted to it by the external force is insufficient to reach the unstable configuration, the second magnetic element returns to its original position. This ensures that action can only be applied once the unstable configuration is reached. Furthermore, when the energy imparted by the external force is sufficient, the magnet of the second magnetic element interacts with the magnet of the first magnetic element of opposite polarity.The second component is then moved, driven by the attraction of magnets of opposite polarity, until it reaches a stable equilibrium position. This also ensures that the intended action is performed. Advantageously, the actuator according to the invention combines, in a single device, the functions of detecting a physical phenomenon and executing an action triggered after the detection of said phenomenon.

[0011] The constant distance along the X axis, between the magnets of the first magnetic element and the magnets of the second magnetic element, predetermines the maximum repulsive force, which is proportional to said distance.

[0012] As will be explained in more detail later, by maintaining a small distance between the first and second magnetic elements, a small movement of the second magnetic element along the Y-axis allows the actuator to store a large amount of magnetic energy, thus exerting a strong force that enables the second magnetic element to overcome its unstable configuration and reach a stable equilibrium. Two magnets with "reversed polarity" along the X-axis are such that, when traversing said X-axis in one direction, one magnet first presents a south pole and then a north pole, while the other magnet first presents a north pole and then a south pole.

[0013] Preferably, the first magnetic element comprises two magnets of the same polarity along the X-axis and a magnet of opposite polarity along the X-axis positioned between the two magnets of the same polarity. Thus, the second magnetic element can be arranged in a stable initial configuration in which it can be subjected to the action of the external force. Advantageously, this secures the actuator, as the second magnetic element is stabilized in its initial configuration by the presence of the additional magnet of the same polarity.

[0014] Preferably, in the stable equilibrium configuration, the magnet of the second magnetic element faces, along the X-axis, one of the magnets of the first magnetic element of opposite polarity. One of the magnets of the first magnetic element is then positioned with opposite poles to the magnet of the second magnetic element. These magnets then attract each other. Thus, the first and second magnetic elements tend to return to the stable equilibrium configuration when they are displaced relative to each other towards the unstable configuration. Therefore, once this action is performed, the freedom of movement of the second magnetic element is reduced.

[0015] Preferably in the stable equilibrium configuration, the magnet of the second magnetic element is, preferably in its entirety, superimposed on one of the magnets of the first magnetic element of opposite polarity in the stable equilibrium configuration, and vice versa.

[0016] In the unstable configuration, particularly when the relative motion of the first and second magnetic elements is unconstrained, the first and second magnetic elements are stationary relative to each other. However, any infinitesimal relative displacement of the first and second magnetic elements with respect to each other then results in the release of stored magnetic energy as mechanical energy by setting the first and second magnetic elements in motion relative to each other.

[0017] Preferably, in the unstable configuration, the magnet of the second magnetic element faces, along the X-axis, and preferably is fully superimposed on, one of the magnets of the first magnetic element of the same polarity. The first and second magnetic elements are preferably identical. This simplifies the actuator design.

[0018] Preferably, the opposite faces of the magnets of the first magnetic element and the magnet of the second magnetic element are of identical shape and area.

[0019] Preferably, the magnets of the first magnetic element and the magnet of the second magnetic element have the same length measured along the Y axis of translation.

[0020] The first magnetic element and / or the second magnetic element preferably comprise a support bearing the magnets, the support being diamagnetic, for example made of copper or brass, or paramagnetic, for example made of an aluminum or tungsten alloy. The support is preferably made of a material having a magnetic susceptibility which, in absolute value, is less than 10⁻¹⁰ m / s². 5 , in order to disturb as little as possible the magnetic interactions between the magnets of the first magnetic organ and the magnet of the second magnetic organ.

[0021] The support may include at least one recess, each housing at least one magnet. Alternatively, the magnets may cover one face of the support. In yet another variation, some magnets may be arranged in recesses, and other magnets may cover one face of the support.

[0022] Preferably, the support has as many slots as there are magnets, with each magnet placed in one of the corresponding slots.

[0023] The magnets of the first magnetic element and the magnet of the second magnetic element are permanent magnets. The magnets of the first magnetic element and the magnet of the second magnetic element may be neodymium magnets, specifically made of a material with the formula Nd2Fe4B, the grade of which can be determined according to the desired maximum repulsion force.

[0024] The magnets of the first magnetic element and the magnet of the second magnetic element are preferably identical. For example, they have the shape of a plate.

[0025] When viewed along the X-axis, at least 50% of the surface area of ​​the first magnetic element and / or at least 50% of the surface area of ​​the second magnetic element can be covered by the magnets. Preferably, the actuator comprises a first magnetic mechanism including several first magnetic elements, in particular rigidly connected to each other, with the second magnetic element being positioned between the first magnetic mechanisms.

[0026] The actuator may also include a second magnetic mechanism comprising several second magnetic elements, in particular rigidly connected to each other, the first magnetic mechanism and the second magnetic mechanism being interdigitated.

[0027] Preferably, the support for the second magnetic element has at least one housing that passes completely through the support along the X-axis. The magnet is located in the housing, having a north pole that interacts with at least one of the magnets of a first magnetic element facing said magnet, and the north pole of said magnet interacts with at least one of the magnets of another first magnetic element facing it along the X-axis. In this way, the magnet of the second magnetic element interacts with the adjacent first magnetic elements, separating them along the X-axis. The actuator is thus particularly compact.

[0028] The external force can be an inertial force, a force resulting from the pressure of a gas, in particular a depression or an overpressure.

[0029] The action to be performed can be chosen from:

[0030] - the opening or closing of an electrical circuit,

[0031] - the opening or closing of a fluid circulation circuit,

[0032] - the locking or unlocking of a kinematic mechanism.

[0033] The action to be performed can be any action requiring force and / or movement.

[0034] The invention will be better understood upon reading the detailed description and examples that follow, presented by way of illustration and not limitation, and the attached drawing, in which:

[0035] [Fig. 1] is a perspective view of an example of an actuator according to the invention;

[0036] [Fig. 2] is an exploded view of the example actuator;

[0037] [Fig. 3] is a perspective and longitudinal section view of the example actuator in a stable initial configuration;

[0038] [Fig. 4] is a perspective and longitudinal sectional view of the example actuator in an unstable configuration; [Fig. 5] schematically illustrates the operation of the example actuator;

[0039] In the figures, the dimensions and scales of the various constituent elements of the actuator according to the invention have not always been strictly adhered to, for the sake of clarity. Furthermore, some elements have not necessarily been shown in contact with each other, even though they are in practice.

[0040] Figures 1 to 5 show an example of actuator 1 according to the invention.

[0041] The actuator 1 extends along a Y axis and has a general cylindrical shape of revolution.

[0042] It comprises a first magnetic element 2 and a second magnetic element 3 which is movable in translation along the Y axis relative to the first magnetic element.

[0043] The first magnetic element 2 comprises a support 4 having a general shape of a cylinder of revolution with axis Y, and three upper 5a, intermediate 5b and lower 5c stages of permanent magnets.

[0044] The support 4 has a straight groove 6 which extends along the Y axis and crosses it diametrically from a bottom wall 7 to a longitudinal opening 8 on a longitudinal face 9 opposite to the bottom wall.

[0045] It also includes two flat surfaces 10 extending along the Y axis from the bottom wall 7 to the longitudinal face 9.

[0046] The flats 10 and the groove 6 define two lateral walls 11, 12 which each extend parallel to the Y axis and which are spaced from each other by a constant distance d by the groove 6.

[0047] Each side wall 11, 12 is hollow and provided with three parallelepiped-shaped recesses 13 arranged in tiers. A permanent magnet 14 is housed in a recess 13 at each tier. In an alternative variant not shown, only one of the side walls 11, 12 may carry the magnets.

[0048] The recesses 13 can be of identical shape and size. They are aligned along the Y axis and are preferably spaced in pairs at a constant distance.

[0049] The recesses are separated from the groove 6 by a partition 15 whose thickness e is constant along the Y axis.

[0050] Within each side wall 11,12, the magnets are arranged along the Y axis with reversed polarities along an X axis perpendicular to the Y axis and to the inner side face of the wall. Thus, as schematically illustrated in Figure 5, in each wall 11,12, the magnet placed in the central recess at level 5b has poles oriented in a first direction along the X axis and the magnets placed in the recesses at the lower level 5c and upper level 5a have poles oriented in a second direction along the X axis. In other words, by traversing the Y axis from the bottom wall 7 towards the opening 8, designating as magnets "NS" and "SN" magnets whose poles are oriented from north to south and from south to north respectively while traversing the X axis, one encounters successively in each side wall a stack formed by a magnet "NS", a magnet "SN" and a magnet "NS".

[0051] The second magnetic element 3 is shaped to slide in the groove 6 along the Y axis.

[0052] In particular, it includes a support 16 and a magnet 17 housed in the support.

[0053] The support 16 of the second magnetic element 3 has the shape of a cylinder of revolution having the same diameter as the first magnetic element, in which two symmetrical lateral recesses 18 are formed. These lateral recesses 18 are symmetrical to each other with respect to a longitudinal plane containing the Y-axis. They each extend along the entire height of the second magnetic element 3 between its two opposite longitudinal faces 19, 20.

[0054] The two lateral recesses 18 each have a width 1' which is equal to the width of the groove 6 and delimit a central wall 21 whose thickness e' is equal to the thickness d of the groove.

[0055] The thickness e' and the width d are respectively measured transversely to the Y axis.

[0056] The lateral recesses 18 are arranged on either side of the central wall 21 and each separates two lateral blocks 22. The lateral blocks have inner faces opposite the side of each recess which are spaced at a distance equal to the thickness of a lateral wall of the first magnetic element.

[0057] In this way, the side blocks 22 are guided by the flats 10 and the central wall 21 by the groove so that the second magnetic element 3 is mobile only in translation along the Y axis relative to the first magnetic element 2.

[0058] The central wall further comprises a slot 23 with axis Y and rectangular cross-section, in which a permanent magnet "NS" is disposed. It also comprises two partitions 24, each defining an outer face of the wall and, opposite it along the X-axis, a face of the slot. At least one of the partitions may have a hole 25 passing through its thickness, in order to ensure the correct positioning of the magnet of the second magnetic element.

[0059] Since the partitions 24 of the central wall and the partitions 15 of the side walls are of constant thickness, the distance d', measured along the X axis, between a magnet of the first magnetic element 2 and a magnet of the second magnetic element 3, is also constant.

[0060] Furthermore, the actuator includes a cover 26, rigidly fixed to the support of the first magnetic element, which is superimposed on the longitudinal opening of said support. Thus, the cover and the bottom wall of the support of the first magnetic element define stops between which the second magnetic element is movable along the Y-axis.

[0061] Figure 5 illustrates different configurations of the first example of an actuator. According to a stable initial configuration, illustrated in Figure 5a), the magnet 17 of the second magnetic element 3 is arranged in the upper position along the Y axis. Its north and south poles are opposite the south and north poles respectively of the magnets 13 of the upper stage 5a of the first magnetic element 2. In this configuration, the magnets 13 of the upper stages 5a of the first magnetic element and the magnet of the second magnetic element attract each other, being of reversed polarity.

[0062] When the second magnetic element is displaced along the Y-axis by an external force F towards the intermediate stage 5b of magnets 13 of the first magnetic element 2, the north and south poles of the magnet 17 of the second magnetic element 3 are then progressively positioned opposite the north and south poles of the magnets 14 of the intermediate stage of the first magnetic element 2, as illustrated in Figure 5b). The poles of the magnet 17 of the second magnetic stage 3 then gradually come opposite the poles of the same polarity of the magnet 14 of the first magnetic element 2, which increases the repulsion between the first 2 and second 3 magnetic elements, until an unstable configuration is illustrated in Figure 5c) where the magnet 17 of the second magnetic element 3 is completely superimposed on the magnets 14 of the intermediate stage 5b of the first magnetic element 2 along the X-axis.

[0063] Thus, when the energy supplied by the application of the external force F exerted on the second magnetic element 3 was sufficient to bring it into the intermediate configuration between the intermediate stage 5b and the upper stage 5a of the first magnetic element 1 (illustrated in Figure 5b), but insufficient to bring it into the unstable configuration illustrated in Figure 5c, the attraction between the magnets 14 and 17 of the upper stage 5a of the first magnetic element 2 and the second magnetic element 3, and the repulsion between the magnets of the intermediate stage 5b of the first magnetic element 2 and the second magnetic element 3, act as a restoring force that returns the second magnetic element 3 to the initial stable configuration illustrated in Figure 5a, as illustrated in Figure 5d). The energy supplied by the application of the external force is then insufficient to trigger an action by the actuator.

[0064] If the energy supplied by the application of said external force F has brought the second magnetic element into the unstable configuration illustrated in Figure 5 c) with a non-zero velocity, an action can then be triggered by the actuator.

[0065] The second magnetic element then continues its path along the Y axis towards the lower face 7 as illustrated in Figure 5 e). The repulsive force between the second magnetic element 3 and the magnet 14 of the intermediate stage 5b of the first magnetic element 2 decreases with increasing distance between the magnet 17 of the second magnetic element 3 and the magnet 14 of the intermediate stage 5b of the first magnetic element 2. Furthermore, the magnet 17 of the second magnetic element 3 enters into magnetic interaction with the magnets 14 of the lower stage 5c of the first magnetic element 2, which are of opposite polarity.The attraction between the magnets 14 of the lower stage 5c of the first magnetic element 2 and the magnet 17 of the second magnetic element 3 and the repulsion between the magnets of the intermediate stage 5b of the first magnetic element and the magnet 17 of the second magnetic element act as a restoring force which, as illustrated in Figure 5 e), brings the second magnetic element 3 into the stable equilibrium configuration illustrated in Figure 5 f). This ensures that the action to be performed can be carried out.

[0066] For example, in the stable equilibrium configuration, the action to be performed can be carried out by bringing the lower face 25 of the second magnetic element into contact with the inner face 7, this contact being able to close an electrical circuit.

[0067] The second magnetic element cannot move freely from its equilibrium position. The actuator thus ensures the safety of the action performed.

Claims

Demands 1. Actuator (1) comprising a first magnetic mechanism having several first magnetic elements (2), the first (2) and second (3) magnetic elements spaced apart from each other by a fixed distance (d') along an axis X, the first magnetic element (2) comprising at least two permanent magnets (14) of reversed polarity along the axis X and the second magnetic element comprising at least one permanent magnet (17), at least one of the magnets (14) of the first magnetic element (2) interacting magnetically with the magnet (17) of the second magnetic element (3) in at least one configuration of the actuator,the second magnetic element (3) being movable in translation relative to the first magnetic element (2) along a translation axis Y perpendicular to the axis X between at least one stable equilibrium configuration where the magnetic attraction force between the first and second magnetic elements is maximum and at least one unstable configuration where the magnetic repulsion force between the first and second magnetic elements is maximum, the second magnetic element being disposed between the first magnetic mechanisms and comprising a support which includes at least one housing which passes through said support along the axis X, the magnet being disposed in the housing having a north pole interacting with at least one of the magnets of a first magnetic element which faces said magnet and the north pole of said magnet interacting with at least one of the magnets of another first magnetic element which faces it along the axis X,the actuator being configured so that the second magnetic element (3) is driven in translation along the translation axis Y towards the stable equilibrium configuration under the effect of an external force (F) applied to the actuator and to trigger an action when the second magnetic element (3) reaches the stable equilibrium configuration after having passed through the unstable configuration in its movement.

2. Actuator according to claim 1, the first (2) and second (3) magnetic members being identical.

3. Actuator according to any one of claims 1 and 2, the facing faces of the magnets of the first magnetic element and of the magnet of the second magnetic element being of identical shape and area.

4. Actuator according to any one of the preceding claims, the first magnetic member (2) comprising two magnets of the same polarity along the X axis and a magnet of reversed polarity along the X axis which is disposed between the two magnets of the same polarity.

5. Actuator according to any one of the preceding claims, in the stable equilibrium configuration, the magnet of the second magnetic element facing along the X axis one of the magnets of the first magnetic element of opposite polarity.

6. Actuator according to any one of the preceding claims, the first magnetic member and the second magnetic member being stationary relative to each other.

7. Actuator according to any one of the preceding claims, the first magnetic member (2) and / or the second magnetic member (3) comprising a support (4,16) carrying the magnets (14,17), the support being diamagnetic, for example in copper or brass, or paramagnetic, for example in an alloy of aluminium or tungsten.

8. A method for triggering an action, comprising: - the application of an external force on the actuator according to any one of the preceding claims to drive the second magnetic element in translation along the Y-axis relative to the first magnetic element and transmit, the intensity of the external force being sufficient for the second magnetic element to reach the stable equilibrium configuration after passing through the unstable configuration in its movement, and - triggering an action when the second magnetic element is in the stable equilibrium configuration.

9. A method according to the preceding claim, the action to be performed being chosen from: - the opening or closing of an electrical circuit, - the opening or closing of a fluid circulation circuit, and - the locking or unlocking of a kinematic mechanism.

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