Safety-triggered actuator

Abstract

Actuator (1) comprising first (2) and second (3) magnetic elements spaced apart by a fixed distance (d') along an axis X, the first element (2) comprising two magnets (14) of opposite polarity and the second element comprising one magnet (17), one of the magnets (14) of the first element (2) interacting magnetically with the magnet (17) of the second element (3), the second element (3) being movable in translation along an axis Y perpendicular to the axis X between a stable equilibrium configuration where the attractive force between the elements is maximum and at least one unstable configuration where the repulsive force between the elements is maximum, the second element (3) being driven towards the stable equilibrium configuration by an applied external force (F) and triggering an action when the second element (3) reaches the stable equilibrium configuration after passing through the unstable configuration. Figure for the abbreviation: Fig. 1

Description

Title of the invention: Safety-triggered actuator

[0001] The present invention relates to securing the triggering of an actuator.

[0002] Actuators are known that trigger an action when subjected to an external force, which may 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 triggering threshold. In other words, they do not guarantee that the action they are supposed to perform has actually been carried out.

[0003] There is therefore a need to overcome this drawback.

[0004] The invention relates to an actuator comprising first and second magnetic elements spaced a fixed distance apart along an axis X, the first magnetic element comprising at least two permanent magnets of opposite polarity along the 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 configuration of the actuator, the second magnetic element being movable in translation relative to the first magnetic element 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 actuator being configured so that the second magnetic element is driven in translation along the Y-axis towards the stable equilibrium configuration under the effect of an external force applied to the actuator, and to trigger an action when the second magnetic element reaches the stable equilibrium configuration after having passed through the unstable configuration in its movement.

[0005] It also relates to a method for triggering an action, comprising: - 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 - triggering an action when the second magnetic element is in the stable equilibrium configuration.

[0006] When an external force is applied to the actuator, for example, by 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 application of the external force is insufficient to reach the unstable configuration, the second magnetic element returns to its original position. This ensures that the action can only be applied once the unstable configuration is reached. Furthermore, when the energy imparted by the application of the external force is sufficient, the magnet of the second magnetic element then 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.

[0007] The constant distance along the X axis, between the magnets of the first magnetic element and the magnets of the second magnetic element, fixes in a predetermined manner the maximum repulsion force, which is proportional to said distance.

[0008] As will be shown in more detail later, by imposing a small distance between the first magnetic element and the second magnetic element, a small movement of the second magnetic element along the Y axis allows the actuator to store a high amount of magnetic energy, and thus to impose a high force so that the second magnetic element can overcome the unstable configuration to reach the stable equilibrium configuration.

[0009] Two magnets of "reversed polarity" along the X axis are such that when traversing said X axis in one direction, one of the magnets presents first a south pole and then a north pole while the other of the magnets presents first a north pole and then a south pole.

[0010] 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, which is 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 the initial configuration by the presence of the additional magnet of the same polarity.

[0011] 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 in opposite polarity 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.

[0012] 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.

[0013] 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 the stored magnetic energy in the form of mechanical energy by setting the first and second magnetic elements in motion relative to each other.

[0014] Preferably, in the unstable configuration, the magnet of the second magnetic element faces along the X axis, preferably is fully superimposed, on one of the magnets of the first magnetic element of the same polarity.

[0015] The first magnetic element and the second magnetic element are preferably identical. This simplifies the design of the actuator.

[0016] 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.

[0017] Preferably, the magnets of the first magnetic element and the magnet of the second magnetic element have an identical length measured along the Y axis of translation.

[0018] The first magnetic element and / or the second magnetic element preferably comprise a support for 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 10⁵, in order to minimize disturbance to the magnetic interactions between the magnets of the first magnetic element and the magnet of the second magnetic element.

[0019] The support may include at least one housing, each housing at least one of the magnets. Alternatively, the magnets may cover one face of the support. According to yet another alternative, some magnets may be arranged in housings and other magnets may cover one face of the support.

[0020] Preferably, the support has as many housings as there are magnets, each magnet being disposed in one of the corresponding housings.

[0021] 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, in particular made of a material of formula Nd2Fe4B, the grade of which may be determined according to the maximum desired repulsion force.

[0022] 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.

[0023] When viewed along the X axis, at least 50% of the surface of the first magnetic element and / or at least 50% of the surface of the second magnetic element can be covered by the magnets.

[0024] Preferably, the actuator comprises a first magnetic mechanism comprising several first magnetic elements, in particular rigidly connected to each other, the second magnetic element being disposed between the first magnetic mechanisms.

[0025] The actuator may further 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.

[0026] Preferably, the support for the second magnetic element comprises at least one housing which passes completely through said support along the X-axis, the magnet being disposed in the housing having a north pole interacting with at least one of the magnets of a first magnetic element facing said magnet and the north pole of said magnet interacting 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 first adjacent magnetic elements which it separates along the X-axis. The actuator is thus particularly compact.

[0027] The external force can be an inertial force, a force resulting from a pressure of a gas, in particular a depression or an overpressure.

[0028] The action to be performed can be chosen from: - the opening or closing of an electrical circuit, - the opening or closing of a fluid circulation circuit, - the locking or unlocking of a kinematic mechanism.

[0029] The action to be performed can be any action requiring force and / or displacement.

[0030] The invention will be better understood upon reading the detailed description and The following examples, presented for illustrative and non-exhaustive purposes, and the attached drawing, in which:

[0031] [Fig-1] is a perspective view of an example of an actuator according to the invention;

[0032] [Fig.2] is an exploded view of the example actuator;

[0033] [Fig.3] is a perspective and longitudinal sectional view of the example of actuator in a stable initial configuration;

[0034] [Fig.4] is a perspective and longitudinal sectional view of the example actuator in an unstable configuration;

[0035] [Fig.5] schematically illustrates the operation of the example actuator;

[0036] 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 in the drawing. Furthermore, some elements have not necessarily been shown in contact with each other, whereas they are in practice.

[0037] Figures 1 to 5 show an example of actuator 1 according to the invention.

[0038] The actuator 1 extends along a Y-axis and has a generally cylindrical shape of revolution.

[0039] It comprises a first magnetic element 2 and a second magnetic element 3 movable in translation along the Y axis relative to the first magnetic element.

[0040] 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.

[0041] 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.

[0042] It also includes two flats 10 extending along the Y axis from the bottom wall 7 to the longitudinal face 9.

[0043] 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.

[0044] 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 embodiment not shown, only one of the side walls 11, 12 may carry the magnets.

[0045] The recesses 13 can be of identical shape and size. They are aligned along the Y axis and are preferably spaced two by two at a constant distance.

[0046] The recesses are separated from the groove 6 by a partition 15 whose thickness e is constant along the Y axis.

[0047] 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 [Fig. 5], in each wall 11, 12, the magnet placed in the central recess on the floor 5b has poles oriented in a first direction along the X axis and the magnets placed in the recesses on the lower floor 5c and upper floor 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".

[0048] The second magnetic element 3 is shaped to slide in the groove 6 along the Y axis.

[0049] In particular, it includes a support 16 and a magnet 17 housed in the support.

[0050] 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 the two opposite longitudinal faces 19, 20 of the latter.

[0051] 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.

[0052] The thickness e' and the width d are respectively measured transversely to the Y axis.

[0053] 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.

[0054] In this way, the lateral 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.

[0055] The central wall further comprises a slot 23 with axis Y and rectangular cross-section, in which a permanent magnet "NS" is disposed. It comprises In addition, there are 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.

[0056] 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.

[0057] 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.

[0058] Figure 5 illustrates different configurations of the first example of an actuator. According to a stable initial configuration, illustrated in Figure 5 a), 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.

[0059] When the second magnetic element is moved along the Y axis under the effect of 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 arranged opposite the north and south poles of the magnets 14 of the intermediate stage of the first magnetic element 2, as illustrated in [Fig.5] b). The poles of the magnet 17 of the second magnetic stage 3 then gradually come into contact with the poles of the same polarity of the magnet 14 of the first magnetic organ 2, which increases the repulsion between the first 2 and second 3 magnetic organs, up to an unstable configuration illustrated on [Fig.5] c) where the magnet 17 of the second magnetic organ 3 is fully superimposed on the magnets 14 of the intermediate stage 5b of the first magnetic organ 2 along the X axis.

[0060] Thus, when the energy supplied by the application of the external force F exerted on the second magnetic element 3 was sufficient to bring the latter into the intermediate configuration between the intermediate stage 5b and the upper stage 5a of the first magnetic element 1 illustrated in [Fig. 5] b) but insufficient to bring it into the unstable configuration illustrated in [Fig. 5] c), the attraction between the magnets 14 and 17 of the upper stage 5a of the first magnetic element 2 and of 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 which returns the second magnetic element 3 to the initial stable configuration illustrated in [Fig.5] a), as illustrated in [Fig.5] d). The energy supplied by the application of the external force is then insufficient for an action to be triggered by the actuator.

[0061] If the energy supplied by the application of said external force F has brought the second magnetic element into the unstable configuration illustrated in [Fig.5] c) with a non-zero velocity, an action can then be triggered by the actuator.

[0062] The second magnetic element then continues its course along the Y axis towards the lower face 7 as illustrated in [Fig. 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 to it. The attraction between the magnets 14 of the lower stage 5c of the first magnetic organ 2 and the magnet 17 of the second magnetic organ 3 and the repulsion between the magnets of the intermediate stage 5b of the first magnetic organ and the magnet 17 of the second magnetic organ act 3 as a restoring force which causes, as illustrated in the [Fig.5] e), the second magnetic element 3 in the stable equilibrium configuration illustrated in [Fig.5] f). This ensures that the action to be performed can be carried out.

[0063] 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.

[0064] The second magnetic element cannot move freely from the equilibrium configuration. The actuator thus ensures the safety of the action performed.

Claims

Demands

1. Actuator (1) comprising first (2) and second (3) magnetic elements spaced apart 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 X axis 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 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 member magnetic 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. Method for triggering an action, comprising: - applying an external force to 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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