Pressure switch with electrical switch

Abstract

The present invention relates to a pressure switch (1) comprising: - a first electrical conductor (3a) and a second electrical conductor (3b) at a distance from the first electrical conductor (3a), - a pushbutton (5) comprising a third electrical conductor (3c), the pushbutton (5) being movable translationally relative to the first electrical conductor and to the second electrical conductor (3a, 3b) between: - a first position in which the third electrical conductor (3c) does not electrically join the first electrical conductor (3a) to the second electrical conductor (3b), and - a second position in which the third electrical conductor (3c) electrically joins the first electrical conductor (3a) to the second electrical conductor (3b), - a deformable diaphragm (6) configured to move the pushbutton (5) between the first position and the second position under the effect of a variation in pressure exerted by a fluid.

Description

[0001] DESCRIPTION

[0002] TITLE: Pressure switch with electric switch

[0003] FIELD OF INVENTION

[0004] The invention relates generally to the field of sensors, more particularly to sensors for crossing a predetermined pressure threshold, also called pressure switches, pressure switches, vacuum switches or pressure contacts.

[0005] STATE OF THE ART

[0006] The prior art includes numerous fluidic systems incorporating one or more pressure switches used to detect when a pressure threshold is crossed by a change in electrical conductor, both in rising and falling pressure. For example, aircraft air, oil, or fuel circuits are controlled in real time using these switches, which are integrated into a control circuit. A pressure switch comprises a cylindrical body containing a sealing diaphragm in contact with the fluid and supported by an elastic diaphragm. The elastic diaphragm is shaped to flex once the hydraulic stress on the fluid reaches the target operating value.This buckling generates a rapid movement of the pressure switch's moving parts, including, for example, a diaphragm known as a "fork" or a hermetic crosshead, which come into contact with a microswitch (also called a quick-acting switch or "microswitch" in English terminology). The microswitch is thus actuated and changes the electrical connections of the control circuit. Document EP1619701 B1 describes such a microswitch, which includes a bistable spring; each stable position of this spring defines a switching position of the microswitch.

[0007] However, these moving parts, combined with the microswitch, make the pressure switch complex and increase its size.

[0008] Therefore, there is a need for a simpler and more compact pressure switch. DESCRIPTION OF THE INVENTION

[0009] One aim of the present invention is to remedy the aforementioned drawbacks by proposing a pressure switch comprising a pusher that translates between different positions under the effect of a deformable diaphragm.

[0010] To this end, the invention proposes a pressure switch comprising:

[0011] - a first electrical conductor and a second electrical conductor located at a distance from the first electrical conductor,

[0012] - a push button comprising a third electrical conductor, the push button being movable in translation relative to the first conductor and the second electrical conductor between:

[0013] - a first position in which the third electrical conductor does not electrically connect the first electrical conductor to the second electrical conductor,

[0014] - a second position in which the third electrical conductor electrically connects the first electrical conductor to the second electrical conductor,

[0015] - a deformable membrane configured to move the pusher between the first position and the second position under the effect of a pressure variation exerted by a fluid.

[0016] The pusher further comprises an electrical insulator having a first face and a second face opposite the first face, the first and second faces extending parallel to an axis of translation of the pusher relative to the first and second electrical conductors. The electrical insulator also defines a channel containing the third electrical conductor, the third electrical conductor having two opposite ends opening into the first and second faces, respectively.

[0017] The pressure switch according to the invention is advantageously complemented by the following features, taken individually or in one of their technically possible combinations:

[0018] - a fourth electrical conductor located at a distance from the first and second electrical conductors, and in which:

[0019] - the push button is movable relative to the fourth electrical conductor,

[0020] - The push button includes a fifth electrical conductor; - when the push button is in the first position, the fifth electrical conductor electrically connects the fourth electrical conductor to the first electrical conductor.

[0021] - when the push button is in the second position, the fifth electrical conductor does not electrically connect the fourth electrical conductor to the first or second electrical conductor;

[0022] - a guide delimiting a passage, the pusher being movable in translation within the passage relative to the guide;

[0023] - the pusher has a first face and a second face opposite to the first face, the first face and the second face extending parallel to an axis of translation of the pusher with respect to the first electrical conductor and the second electrical conductor, and the third electrical conductor having two opposite ends opening respectively into the first face and into the second face;

[0024] - the two opposite ends of the third electrical conductor are flush with the first face and the second face respectively; - the pusher has a third face perpendicular to the first face and the second face, the third face extending parallel to the axis of translation, and the fifth electrical conductor has two opposite ends opening into the first face and the third face respectively;

[0025] - the electrical insulator delimits the third face;

[0026] - the two opposite ends of the fifth electrical conductor are flush with the first face and the third face respectively;

[0027] - the electrical insulator delimits another channel in which the fifth electrical conductor is contained;

[0028] - a stop to limit a translational stroke of the pusher relative to the first electrical conductor and the second electrical conductor, in which in the first position the pusher is in contact with the stop and in the second position the pusher is not in contact with the stop;

[0029] - a housing containing the guide, the housing having a first thread, and the guide having a second thread, the first thread and the second thread being adapted to allow the guide to be screwed to the housing and unscrewed from the housing;

[0030] - at least one of the electrical conductors is arranged in a plane perpendicular to an axis of translation of the pusher; - at least one of the first electrical conductor, the second electrical conductor and the fourth electrical conductor includes an electrically conductive strip, each strip comprising a first portion arranged on a surface of the guide and a second portion configured to be electrically joined with one of the third and fifth electrical conductors, depending on the position of the pusher.

[0031] The pressure switch according to the invention solves the problem by replacing currently used moving parts, such as microswitches, with a push button that, depending on its position, establishes the electrical connections for the desired pressure values ​​directly under the action of the deformable diaphragm. The pressure switch according to the invention thus comprises fewer parts and is consequently simpler. Furthermore, thanks to this simplification, the pressure switch according to the invention is more compact, as the push button requires less space than current moving parts.

[0032] DESCRIPTION OF THE FIGURES

[0033] Other features, purposes and advantages of the invention will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which:

[0034] Figure 1 illustrates a schematic cross-sectional view of a pressure switch according to one embodiment;

[0035] Figure 2 illustrates a schematic cross-sectional view of a pressure switch according to another embodiment;

[0036] Figure 3 illustrates a schematic profile view of a guide for a pressure switch from Figure 2;

[0037] Figure 4 illustrates a schematic cross-sectional view of the guide in Figure 3, including a pusher in a first position;

[0038] Figure 5 illustrates a schematic cross-sectional view of the guide in Figure 4, including a pusher in a second position;

[0039] Figure 6 illustrates a schematic profile view of a pressure switch guide in which a push button is in a first position, according to another embodiment of the invention;

[0040] Figure 7 illustrates a schematic profile view of the guide in Figure 6, in which the pusher is in a second position. Throughout the figures, similar elements are identified by identical reference numerals.

[0041] DETAILED DESCRIPTION OF THE INVENTION

[0042] With reference to Figure 1, a pressure switch 1 according to a first embodiment comprises a housing 2, first electrical conductor 3a, second electrical conductor 3b, a guide 4, a push button 5 and an elastic diaphragm 6.

[0043] Housing 2 defines an internal volume configured to receive the other elements of the pressure switch 1 mentioned above, and housing 2 includes a first end, configured to receive a fluid, and a second end configured to receive the first and second electrical conductors 3a, 3b. The first and second electrical conductors 3a, 3b are arranged at a distance from each other in order to isolate them electrically, so that an electrical contact between the two cannot be established spontaneously.

[0044] The guide 4 is arranged in the housing 2, advantageously in a removable manner to facilitate the mounting of the pressure switch 1. Preferably, the housing 2 has a first thread and the guide 4 has a second thread, so that the guide 4 can be screwed into and unscrewed from the housing 2. The guide 4 includes a passage 41 extending through the guide 4 from a first proximal surface 4a of the first and second electrical conductors 3a, 3b and from a second proximal surface 4b of the deformable diaphragm 6. The passage 41 preferably extends along an axis passing through the first and second ends. The passage 41 is configured to receive a pusher 5 such that the pusher is free to translate within the passage 41 along a translational axis A.

[0045] The pusher 5 can therefore adopt several positions on the axis A, that is to say that the pusher 5 is mobile relative to the first and second electrical conductors 3a, 3b.

[0046] The pusher 5 includes an electrical insulator which is preferably of the same shape as the passage 41, for example in the shape of a prism, preferably in the shape of a right prism in order to prevent any rotation of the pusher 5 on the axis A. The pusher 5 includes a third electrical conductor 3c. The third electrical conductor 3c is contained in a channel delimited by the electrical insulator.

[0047] The electrical insulator of the push button 5 is, for example, in the shape of a right prism with a rectangular base and therefore comprises two bases 50 and four faces, in particular a first face 51a and a second face 51b opposite the first face 51a. By opposite, we mean in particular that the first face 51a and the second face 51b are parallel and connected by the bases 50 of the push button 5 without being in direct contact. The first face 51a and the second face 51b each conform respectively to a surface of the passage 41. One base 50 is proximal to the first electrical conductor 3a and the second electrical conductor 3b, while the other base 50 is proximal to the deformable membrane 6.

[0048] The third electrical conductor 3c has two opposite ends opening respectively into the first face 51a and the second face 51b of the electrical insulator of the push button 5. Preferably, these ends are flush with the faces 51a, 51b respectively.

[0049] In a first position, the third electrical conductor 3c is separated from the first and second electrical conductors 3a, 3b, so that no electrical connection is established between the first, second, or third electrical conductors 3a, 3b, 3c. The third electrical conductor 3c extends between the first face 51a and the second face 51b of the push button 5. The third electrical conductor 3c has two ends 31c configured to make electrical contact. The push button 5 includes an electrically insulating material covering the third electrical conductor 3c, except for the two ends 31c. In the first position, the ends 31c are in contact with the surface of the passage 41, which also includes an electrically insulating material, or in contact with air.The first electrical conductor 3a and the second electrical conductor 3b are preferentially arranged on the first surface 4a of the guide 4, so as to fit the passage 41.

[0050] In a second position, the third electrical conductor 3c is configured to establish an electrical connection between the first electrical conductor 3a and the second electrical conductor 3b. The ends 31c of the third electrical conductor 3c are brought into contact with the first and second electrical conductors 3a and 3b, respectively, by the transition from the first to the second position. The pusher 5 is configured to move from one position to the other under the action of the deformable diaphragm 6.

[0051] Advantageously, the pressure switch 1 includes a stop 7 configured to limit the translational stroke of the pusher 5 relative to the guide 4. The stop 7 is, for example, the second surface 4b of the guide 4, a portion of the pusher 5 being configured so as not to be inserted into the passage 41 abutting against the second surface 4b so as to limit the translational stroke of the pusher 5. The position of the pusher 5 in which it is abutted is advantageously selected to be the first or second position of the pusher 5, so as to improve the accuracy of the movement.

[0052] The deformable diaphragm 6 is connected to the plunger 5 and rests against a sealing diaphragm. The sealing diaphragm is in contact with the fluid, preventing it from entering the pressure switch 1. The deformable diaphragm 6 is configured to deform under the effect of a force exerted by the fluid on the sealing diaphragm. The sealing diaphragm transmits the force such that the deformation of the elastic diaphragm 6 causes the plunger 5 to translate. More precisely, the deformation of the deformable diaphragm 6 moves the plunger 5 along axis A by a distance separating two positions of the plunger 5. The deformable diaphragm 6 is preferably an elastic diaphragm configured to buckle when a predetermined value of the applied pressure is reached and to return to its original shape when the applied pressure is less than another predetermined value.Thus, an increase or decrease in the pressure exerted by the fluid on the deformable membrane 6 causes the pusher 5 to change position and therefore the opening or closing of the circuit formed by the first, second and third electrical conductors 3a, 3b, 3c.

[0053] Figures 2 to 5 illustrate a second embodiment in which the pressure switch 1 further includes a fourth electrical conductor 3d located at a distance from the first and second electrical conductors 3a, 3b, so as to electrically isolate them and prevent self-establishment of electrical contact between any two of the first electrical conductor 3a, the second electrical conductor 3b, and the fourth electrical conductor 3d. In addition, the push button 5 includes a fifth electrical conductor 3e configured to electrically connect the fourth electrical conductor 3d to the first electrical conductor 3a in the first position, illustrated in Figure 4. In the second position, illustrated in Figure 5, the fifth electrical conductor 3e is not electrically connected to the fourth electrical conductor 3d, the first electrical conductor 3a, or the second electrical conductor 3b.

[0054] The fifth electrical conductor 3e is contained in a channel delimited by the electrical insulation of the push button 5. This channel is distinct and separate from the one containing the third electrical conductor 3c. In other words, the conductors 3c and 3e forming part of the push button 5 are electrically insulated from each other by the electrical insulation.

[0055] Advantageously, the shape of the push button 5 prevents its rotation within the passage 41, thus preventing each electrical conductor connected to the push button 5 from connecting to a conductor other than the one in its assigned position. Furthermore, for the same position of the push button 5, additional connections can be made beyond those previously described, as both the push button 5 and the housing 2 can each contain as many conductors as necessary to establish these connections.

[0056] Advantageously, all or part of the first, second, third, fourth, and fifth electrical conductors 3a, 3b, 3c, 3d, 3e are arranged perpendicular to the translational axis A of the pusher 5, so that the electrical connections are established precisely, i.e., over a short stroke distance of the pusher 5. For example, the first, second, and fourth electrical conductors 3a, 3b, 3d are arranged on the surface of the guide 4, which facilitates their installation. The third and fifth electrical conductors 3c, 3e are placed inside the pusher 5, so that each of their ends makes contact with the first, second, and fourth electrical conductors 3a, 3b, 3d in the respective position where contact is desired.More precisely, the fifth electrical conductor 3e passes through the pusher 5 between the first face 51a or the second face 51b and a third face 50c of the pusher 5, the third face 51c being perpendicular to the first face 51a and the second face 51b. The fifth electrical conductor 3e has two opposite ends 31e opening respectively into the first face 51a and the third face 51c of the electrical insulation of the pusher 5. Preferably, these ends 31e are flush with the faces 51a and 51c, respectively. The two ends 31e are configured to establish electrical contact. In the first position, the ends 31c are in contact with the surface of the passage 41, which comprises an electrically insulating material, or with air.The first electrical conductor 3a and the second electrical conductor 3b are preferentially arranged on the first surface 4a of the guide 4, so as to fit the passage 41 so that the electrical contact is established in the desired positions.

[0057] The first, second, and fourth electrical conductors 3a, 3b, 3d may each comprise an electrically conductive strip 42, as illustrated in Figures 3 to 5. The strips 42 may be gold-plated. Each strip 42 comprises a first portion 42a, preferably arranged perpendicular to the axis of translation A of the pusher 5, and a second portion 42b configured to be electrically connected to one of the third and fifth electrical conductors 3c, 3e, depending on the position of the pusher 5. The first portions 42a preferably extend over the first surface 4a of the guide 4, to simplify the assembly of the first electrical conductor 3a, the second electrical conductor 3b, and the fourth electrical conductor 3d. The second portions 42b preferably extend into the passage 41, in contact with the pusher 5, to facilitate the re-establishment of electrical connections between the electrical conductors.Advantageously, each second portion 42b forms a spring configured to exert a force on the pusher 5 and ensure contact between the slat 42 and the respective electrical conductor during the translation of the pusher 5.

[0058] With reference to Figure 6, the installation of the third and / or fifth electrical conductor 3c, 3e is facilitated by a central hole 52 which passes through the pusher 5 along the axis A, the central hole 52 allowing visual access and control of the third electrical conductor 3c and / or the fifth electrical conductor 3e.

[0059] The pressure switch 1, according to the embodiments described above, is simpler and more reliable than prior art pressure switches because it comprises fewer components. In particular, the plunger 5 combines the mechanical translation function of the moving elements with the electrical state-changing function of the prior art microswitch, establishing the electrical connections for the desired pressure values ​​directly under the action of the deformable diaphragm 6. Furthermore, thanks to this simplification, the described pressure switch 1 is more compact, as the plunger 5 requires less space than current moving elements. The described pressure switch 1 is particularly well-suited for controlling pressure variations in all types of systems, especially air, oil, or fuel circuits used in hydraulic or pneumatic systems in the aeronautical field.

Claims

DEMANDS 1. Pressure switch (1) comprising: - a first electrical conductor (3a) and a second electrical conductor (3b) at a distance from the first electrical conductor (3a), - a push button (5) comprising a third electrical conductor (3c), the push button (5) being movable in translation relative to the first conductor and the second electrical conductor (3a, 3b) between: - a first position in which the third electrical conductor (3c) does not electrically connect the first electrical conductor (3a) to the second electrical conductor (3b), - a second position in which the third electrical conductor (3c) electrically joins the first electrical conductor (3a) to the second electrical conductor (3b), in which the pusher (5) further comprises an electrical insulator having a first face (51a) and a second face (51b) opposite the first face (51a), the first face (51a) and the second face (51b) extending parallel to an axis (A) of translation of the pusher (5) with respect to the first electrical conductor (3a) and the second electrical conductor (3b), and in which the electrical insulator delimits a channel in which the third electrical conductor (3c) is contained, the third electrical conductor (3c) having two opposite ends (31c) opening respectively into the first face (51a) and into the second face (51b), - a deformable membrane (6) configured to move the pusher (5) between the first position and the second position under the effect of a pressure variation exerted by a fluid.

2. Pressure switch (1) according to claim 1, comprising a fourth electrical conductor (3d) located at a distance from the first electrical conductor (3a) and the second electrical conductor (3b), and wherein: - the pusher (5) is movable relative to the fourth electrical conductor (3d), - the push button (5) includes a fifth electrical conductor (3e), - when the pusher (5) is in the first position, the fifth electrical conductor (3e) electrically connects the fourth electrical conductor (3d) to the first electrical conductor (3a), - when the pusher (5) is in the second position, the fifth electrical conductor (3e) does not electrically connect the fourth electrical conductor (3d) to the first electrical conductor (3a) or to the second electrical conductor (3b).

3. Pressure switch (1) according to any one of the preceding claims, wherein the two opposite ends (31c) of the third electrical conductor (3c) are flush with the first face (51a) and the second face (51b) respectively.

4. Pressure switch (1) according to any one of the preceding claims, wherein the electrical insulator has a third face (51c) perpendicular to the first face (51a) and the second face (51b), the third face (51c) extending parallel to the axis (A) of translation, and the fifth electrical conductor (3e) having two opposite ends (31e) opening respectively into the first face (51a) and into the third face (51c).

5. Pressure switch (1) according to the preceding claim, wherein the two opposite ends (31c) of the fifth electrical conductor (3e) are flush with the first face (51a) and the third face (51c) respectively.

6. Pressure switch (1) according to any one of claims 4 and 5, wherein the electrical insulator delimits another channel in which the fifth electrical conductor is contained.

7. Pressure switch (1) according to any one of the preceding claims, comprising a stop (7) for limiting a translational stroke of the pusher (5) relative to the first electrical conductor (3a) and the second electrical conductor (3b) and wherein in the first position the pusher (5) is in contact with the stop (7) and in the second position the pusher (5) is not in contact with the stop (7).

8. Pressure switch (1) according to any one of the preceding claims, wherein at least one of the electrical conductors (3a, 3b, 3c, 3d, 3e) is arranged in a plane perpendicular to a translation axis (A) of the pusher (5).

9. Pressure switch (1) according to any one of the preceding claims, comprising a guide (4) defining a passage (41), the pusher (5) being movable in translation within the passage (41) in relation to guide (4).

10. Pressure switch (1) according to the preceding claim, comprising a housing (2) containing the guide (4), the housing (2) having a first thread, and the guide (4) having a second thread, the first thread and the second thread being adapted to allow the guide (4) to be screwed to the housing (2) and to be unscrewed from the housing (2).

11. Pressure switch (1) according to any one of claims 9 and 10 in their dependence on claim 2, wherein at least one of the first electrical conductor (3a), the second electrical conductor (3b) and the fourth electrical conductor (3d) comprises an electrically conductive strip (42), each strip (42) comprising a first portion (42a) disposed on a surface (4a) of the guide (4) and a second portion (42b) configured to be electrically joined with one of the third and fifth electrical conductors (3c, 3e), depending on the position of the pusher (5).

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