Electrical contactless switch

Abstract

To provide a simple, low-cost electrical contactless switch that is easy to manufacture.SOLUTION: A moveable element 3 is made of a ferromagnetic material and is slidably attached into a housing 2. The moveable element 3 is adapted to move relative to the housing 2 between a resting position and an engaged position, the moveable element 3 is elastically biased towards the resting position. The moveable element 3 includes a plurality of spaced magnetized legs 4, 6, and at least part of the magnetized legs 4, 6 is slidably guided in the housing 2. The magnetic field sensor 7 is secured to the housing 2 and positioned to face the plurality of magnetized legs 4, 6. The magnetic sensor 7 is configured to detect a magnetic field generated by the magnetized legs 4, 6 as the moveable element 3 is in the engaged position. The moveable element 3 is closer to the magnetic field sensor 7 in the engaged position than in the resting position.SELECTED DRAWING: Figure 1

Description

Technical Field

[0006] , ,

[0001] <0​​​​​​​​​​​​​​​​​​​​​​​​​​​​​One aspect of the present disclosure relates to an electrical non-contact switch. The electrical non-contact switch comprises a housing, a magnetic field sensor, and a movable element. The movable element is formed of a ferromagnetic material and is slidably mounted within the housing. The movable element is adapted to move relative to the housing between a stationary position and an engaged position. The movable element is elastically biased toward the stationary position. The movable element comprises a plurality of magnetized legs spaced apart from each other, at least a portion of which are slidably guided within the housing.

[0007] The magnetic field sensor is fixed to the housing and positioned to face multiple magnetization legs. The magnetic field sensor is configured to detect the magnetic field generated by the magnetization legs when the movable element is in the engaged position. The movable element is closer to the magnetic field sensor when in the engaged position than when in the stationary position.

[0008] Furthermore, the legs of multiple magnetized legs may protrude parallel to one side of the movable element.

[0009] Furthermore, the multiple magnetization legs may be magnetized such that at least one of the multiple magnetization legs is magnetized in the opposite direction to the other multiple magnetization legs.

[0010] Furthermore, the magnetization legs may comprise two side legs and a central leg between the two side legs, with the central leg being magnetized in the opposite direction to the two side legs.

[0011] Furthermore, each of the two side legs may be terminated by a hook that protrudes laterally outward.

[0012] The housing may also have slots that allow movable elements to slide, and the side legs may be snapped into the slots and held in place within the slots by hooks that cooperate with contact portions belonging to the slots.

[0013] The switch may also further include an elastic element at least partially positioned between the multiple magnetized legs and the magnetic field sensor, the elastic element being configured to elastically bias the movable element toward the stationary position and to suppress the movement of the movable element from the stationary position to the engagement position.

[0014] Furthermore, the elastic element may be a compression coil spring.

[0015] Furthermore, the movable elements may be formed from an annealed semi-hard ferromagnetic metal or a hard ferromagnetic metal.

[0016] Furthermore, the annealed ferromagnetic metal may be a cobalt-based metal.

[0017] Furthermore, the movable element may have a plate shape with a thickness of 1 mm to 3 mm.

[0018] Furthermore, the magnetic field sensor may include a Hall effect sensor or a magnetoresistive sensor.

[0019] A further embodiment relates to a method for manufacturing a movable element for an electrically non-contact switch and / or a substitute thereof as defined above. The method includes providing a movable element having a plurality of spaced-apart legs formed of a ferromagnetic material, and magnetizing one of the legs by bringing a permanent magnet into contact with it.

[0020] Multiple magnetized legs may include two side legs and a central leg between the two side legs, and the magnetization of the legs may be carried out by bringing the magnet into contact only with the central leg.

[0021] Furthermore, the magnet may be a permanent magnet, and the movable element may be formed from an annealed semi-hard ferromagnetic metal or a hard ferromagnetic metal.

[0022] Further applicable areas will become apparent from the description in this specification. The descriptions in the summary of the invention and the specific examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure.

[0023] Other features and advantages of the present invention will become apparent from the following detailed description of some of its embodiments given as non-limiting examples and from reference to the accompanying drawings.

Brief Description of the Drawings

[0024] [Figure 1] It is a diagram showing a first embodiment of an electrically non-contact switch. [Figure 2] It is a diagram showing a second embodiment of an electrically non-contact switch in an engaged position. [Figure 3] It is a diagram showing a second embodiment of an electrically non-contact switch in a stationary position. [Figure 4] It is an exemplary diagram showing a movable element before magnetization. [Figure 5] It is an exemplary diagram showing a movable element during magnetization. [Figure 6] It is an exemplary diagram showing a movable element after magnetization near a magnetic field sensor. [Figure 7] It is an exemplary perspective view of a movable element. [Figure 8] It is a flowchart showing an embodiment of a method for manufacturing a movable element for an electrically non-contact switch.

Modes for Carrying Out the Invention

[0025] The above summary and the following detailed descriptions of specific embodiments will be better understood when read in conjunction with the accompanying drawings. Where used herein, elements or steps following the singular form of the word "a" or "an" should be understood as not making such exclusions unless explicitly stated otherwise. Furthermore, references to "one embodiment" are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the described functionality. Moreover, unless explicitly stated otherwise, embodiments "equipping" or "having" one or more elements having a particular characteristic may include additional elements that do not possess that characteristic.

[0026] In the figures, the same reference numerals indicate identical or similar elements unless otherwise specified. For the sake of clarity and ease of explanation, the sizes of elements or specific parts of elements are exaggerated, omitted, or shown schematically in the drawings. Therefore, the sizes of the components may not reflect their actual sizes at all. Detailed descriptions of related known configurations or functions are omitted if it is deemed that such descriptions would obscure the essence of the invention. Figure 1 shows a first embodiment of an electrical non-contact switch 1. The first embodiment comprises a housing 2, a movable element 3, and a magnetic field sensor 7. The movable element can move relative to the housing between a stationary position and an engaged position, as indicated by arrow 12. The movable element can slide within slots 11 and 10 in the housing 2. The movable element 3 may have a plurality of magnetized protrusions that can form a plurality of magnetized legs 4 and 6 spaced apart from each other by having a gap 5 between them. Figure 1 shows two legs, which are a plurality of magnetized legs, but the movable element 3 may have three or more legs. The magnetized legs 4 and 6 may protrude parallel to each other from one side of the movable element 3. The magnetic field sensor 7 may be fixed to the housing and positioned to face the plurality of magnetized legs 4 and 6. The magnetic field sensor 7 may be coupled to a printed circuit board 8 that can be mounted (not shown) in the housing 2. The magnetic field sensor 7 detects the magnetic field generated by the plurality of magnetized legs 4 and 6 when the movable element 3 is in the engaged position. The movable element 3 is closer to the magnetic field sensor 7 when it is in the engaged position than when it is in the stationary position. The magnetic field sensor 14 may include a Hall effect sensor or a magnetoresistive sensor. The magnetic field sensor 14 may also be a Hall effect switch. The movable element is elastically biased toward the stationary position via an elastic element 9 which may be at least partially positioned between the multiple magnetized legs 4 and 6 and the magnetic field sensor 7. The elastic element 9 may restrict the movement of the movable element from the stationary position to the engaged position. The elastic element 9 may be made of elastomer and may have various shapes.

[0027] Figures 2 and 3 show a second embodiment of the electrical non-contact switches 13 and 25. Figure 2 shows a second embodiment of the electrical non-contact switch 13 in the engaged position, and Figure 3 shows a second embodiment of the electrical non-contact switch 13 in the stationary position. The second embodiment comprises a housing 24, a movable element 18, and a magnetic field sensor 14. The movable element can move relative to the housing between the stationary position and the engaged position, as indicated by arrow 30. The movable element 18 may have a plurality of magnetized protrusions that can form a plurality of magnetized legs 16, 19, and 21 that are spaced apart from each other by having a gap between them. The movable element 18 shown in Figures 2 and 3 has three legs, but the movable element may have a number of legs other than three. The magnetized legs 16, 19, and 21 may protrude parallel to each other from one side of the movable element 18. The movable element 18 may have two side legs 16, 21 and a central leg 19 located between the two side legs. Each of the two side legs 16, 21 may be terminated by hooks 29, 26 projecting laterally outward, as shown in Figure 3. The housing 24 may have slots 28, 27 through which the movable element 18 is slidably guided. The side legs 16 and 21 may be snap-fitted into the slots and held within the slots by hooks 26, 29 cooperating with contact portions 20, 17 belonging to the slots.

[0028] The magnetic field sensor 14 may be fixed to the housing and positioned to face a plurality of magnetization legs 16, 19, and 21. The magnetic field sensor 14 may be coupled to a printed circuit board 15 which can be mounted (not shown) on the housing 24. The magnetic field sensor 14 detects the magnetic field generated by the plurality of magnetization legs 16, 19, and 21 when the movable element 18 is in the engagement position 23. The movable element 18 may be closer to the magnetic field sensor 14 when in the engagement position 23, which is shown as a gap, than when in the stationary position. The magnetic field sensor 14 may include a Hall effect sensor or a magnetoresistive sensor. The magnetic field sensor 14 may also be a Hall effect switch.

[0029] When the movable element 18 is in the engagement position 23, there may be multiple magnetic field sensors fixed to the housing to provide redundancy in sensing the magnetic field generated by the multiple magnetization legs 16, 19, and 21. For example, an additional magnetic field sensor 31 may be coupled to the same printed circuit board 15. The printed circuit board 15 may be a single-sided or double-sided printed circuit board 15, and the magnetic field sensor 14 may be soldered to one side of the printed circuit board 15. The additional magnetic field sensor 32 may, advantageously, be coupled to the side of the printed circuit board 15 opposite to the first magnetic field sensor 14. Both magnetic field sensors 14, 32 may be positioned in substantially the same location with only a printed circuit board between them so that both magnetic field sensors detect the magnetic field generated by the multiple magnetization legs 16, 19, and 21 when the movable element 18 moves to the engagement position 23. Both magnetic field sensors may consist of the same sensor or of different types, such as a Hall effect sensor and a magnetoresistive sensor.

[0030] The printed circuit board 15 may, but is not limited to, support other electronic components 13 such as processing and / or protection circuits, communication and / or connection circuits.

[0031] The movable element 18 may be elastically biased toward a stationary position via an elastic element 22 that can be at least partially positioned between the multiple magnetized legs 16, 19, and 21 and the magnetic field sensor 7. The elastic element 22 may restrict the movement of the movable element from the stationary position to the engaged position. The elastic element 22 shown in Figures 2 and 3 may be a compression coil spring. However, other types of elastic elements may be used. Non-limiting examples of such elastic elements may be elastomers of various shapes, leaf springs, spiral springs, tension springs, etc.

[0032] The movable element 18 may be made of a ferromagnetic material. The ferromagnetic material may be a metal. The metal may be a semi-hard or hard ferromagnetic metal. The metal may be made of a cobalt-based metal. The movable element 18 may not be magnetized initially. The semi-hard or hard ferromagnetic metal may be selected from materials having a coercivity Hc of, for example, 25 to 700 A / m. The ferromagnetic material may be in the form of a metal sheet or metal plate. The ferromagnetic material may be ductile and suitable for manufacturing the movable element by stamping or punching. One advantage of such a type of production is the low cost of production of the movable element. Another advantage of such manufacturing is that the movable element, when punched from an unmagnetized metal sheet, simplifies its transport and handling. In general, ductility relates to a material property that represents the ability to not yield to and / or withstand plastic deformation.

[0033] When formed from a metal sheet or metal plate, the movable element 18 may have a plate shape with a thickness ranging from 1 mm to 3 mm, as shown in Figure 7, which illustrates an exemplary perspective view of a movable element 62 of such a plate shape 63. Stamping or punching can be used to create features such as projections 61 that terminate the legs of the movable element 62. The movable element may also be formed by other means, for example, from powder-pressed metal via metal injection molding, or by other methods including different types of metal additive or metal subtractive processes.

[0034] Once the movable element 18 is formed, a heat treatment may be performed. The heat treatment may be annealing. One advantage of annealing is that it hardens the ferromagnetic material of the movable element 18 compared to before annealing, and in the annealed state, the ferromagnetic material of the movable element 18 may exhibit clear, robust, and reproducible magnetic properties.

[0035] Figures 4, 5, and 8 illustrate an exemplary magnetization process of the movable element 18 as described in one of the two embodiments. Figure 4 shows the movable element 18 in an initially unmagnetized state and a source of a magnetic field 36, which may be composed of a permanent magnet 37. Alternatively, the magnetic field source may be an electromagnet (not shown). The permanent magnet 37 may have a south pole at its first end 38 and a north pole at its second end opposite the first end 38.

[0036] The first end 38 of the permanent magnet 37 may be set to face the end 39 of the central leg 19 of the movable element 18. As shown in Figure 5, the first end 38 of the permanent magnet may be moved toward the end 39 of the central leg 45 of the movable element 18 in the direction of arrow 40 in Figure 4 until the first end 38 of the permanent magnet 37 contacts the end 39 of the central leg 45 of the movable element 48. As a result, the movable element 48 may be magnetized by the magnetic field 36 of the permanent magnet generated by the permanent magnet 37. One of the advantages of such a magnetization operation is its simplicity and the ability to be automated into an industrial process.

[0037] The magnetization of the legs may be performed by bringing the magnet into contact with only the central leg 67. Then, the magnetic field lines can pass through the side legs 46, 47 of the movable element 48 and through the central leg 45 of the movable element 48 to close the magnetic circuit. Thus, the central leg 45 of the magnetized movable element 48 can be magnetized in the opposite direction to the side legs 46, 47 of the magnetized movable element 48. As shown in Figures 4 and 5, if the first end 38 of the permanent magnet has a south pole, the central leg 45 of the magnetized movable element 48 can be magnetized as having a north pole, and the side legs can be magnetized to have a south pole.

[0038] Figure 6 shows the magnetic field lines that can be generated when the movable element 48 is magnetized by bringing the permanent magnet 37 into contact only with the central leg 45 of the movable element 48, as described above. The magnetic field lines 51 can then flow from the central leg 45 of the magnetized movable element 48 to the side legs 46 and 47. The magnetic field lines flowing through the gaps 52 and 53 between the central leg 45 and the side legs 46 and 47 of the movable element 48 may be denser than the magnetic field lines 51 that close the gap between the central leg 45 and the side legs 46 and 47 via the magnetic field sensor 14.

[0039] One advantage of the flat, focused shape of the movable element 48 is that it allows for the design of a robust, compact, and contactless electrical switch.

[0040] It should be understood that the above description is intended to be illustrative and not limiting. For example, the embodiments (and / or aspects thereof) described above may be used in combination with each other. Furthermore, many modifications can be made to adapt the teachings of the various embodiments of this disclosure to specific circumstances or materials without departing from the scope of this disclosure. The dimensions and types of materials described herein are intended to specify the parameters of the various embodiments of this disclosure, but these embodiments are not limiting and are illustrative embodiments only. By examining the above description, many other embodiments will be obvious to those skilled in the art. Therefore, the scope of the various embodiments of this disclosure should be determined by referring to the entire scope of equivalents to which those claims are entitled, together with the appended claims. In the appended claims, the words “including” and “in which” are used as plain English equivalents to “comprising” and “wherein,” respectively. Furthermore, terms such as “first,” “second,” and “third” are used merely as symbols and are not intended to impose numerical requirements on their subjects.

[0041] This specification uses examples to disclose various embodiments of the disclosure, including the best mode, and to enable any person skilled in the art to fabricate and use any device or system, and to carry out any of the embodiments of the disclosure, including any methods included. The patentable scope of the various embodiments of the disclosure is defined by the claims and may include other examples that a person skilled in the art may conceive. Such other examples are intended to be included in the claims if they have structural elements that are not different from the language of the claims, or if they include equivalent structural elements that differ only slightly from the language of the claims.

Claims

1. A housing (2, 24); a movable element (3, 18) made of ferromagnetic material and slidably mounted in said housing, adapted to move relative to said housing between a rest position and an engaged position, said movable element being resiliently biased towards said rest position and comprising a plurality of spaced apart magnetized legs (4, 5, 6, 16, 19, 21), at least some of said magnetized legs being slidably guided within said housing; a magnetic field sensor (7, 14) fixed to the housing and arranged facing the magnetized legs, the magnetic field sensor being configured to detect a magnetic field generated by the magnetized legs when the movable element is in the engaged position, the movable element being closer to the magnetic field sensor when in the engaged position than when in the rest position; An electrical contactless switch (1, 13, 25).

2. 2. The electrical contactless switch of claim 1, wherein the legs (4, 5, 6, 16, 19, 21) of the plurality of magnetized legs project in parallel from one side of the movable element.

3. 2. The electrical contactless switch of claim 1, wherein the plurality of magnetized legs are magnetized such that at least one of the plurality of magnetized legs is magnetized in an opposite direction to other of the plurality of magnetized legs.

4. 3. The electrical contactless switch of claim 2, wherein the plurality of magnetized legs comprises two side legs (47, 46) and a central leg (45) between the two side legs, the central leg being magnetized in an opposite direction to the two side legs.

5. 5. An electrical contactless switch according to claim 4, wherein each of said two lateral legs is terminated by a laterally outwardly projecting hook (26, 29).

6. 6. An electrical contactless switch according to claim 5, wherein the housing comprises a slot (27, 28) for slidably guiding the movable element, the side legs being snap-fitted into the slot and held therein by the hooks cooperating with abutments (17, 20) belonging to the slot.

7. 2. The electrical contactless switch of claim 1, further comprising a resilient element (9, 22) disposed at least partially between the plurality of magnetized legs and the magnetic field sensor, the resilient element being configured to resiliently bias the movable element towards the rest position and to inhibit movement of the movable element from the rest position to the engaged position.

8. 8. The electrical non-contact switch according to claim 7, wherein the elastic element is a compression type coil spring (22).

9. 2. The electrical contactless switch of claim 1, wherein the movable element is formed of an annealed semi-hard ferromagnetic metal or a hard ferromagnetic metal.

10. 10. The electrical contactless switch of claim 9, wherein the annealed ferromagnetic metal is a cobalt-based metal.

11. The electrical contactless switch of claim 1 , wherein the magnetic field sensor comprises a Hall effect sensor or a magnetoresistive sensor.

12. 12. The non-contact electrical switch of claim 11, wherein the magnetic field sensor is a Hall effect switch.

13. A method (65) for manufacturing a movable element (3, 62, 66) for an electrical contactless switch (1, 13, 25) according to claim 1, comprising the steps of: Providing (66) said movable element comprising a plurality of spaced apart legs (16, 19, 21) made of ferromagnetic material; Magnetizing (67) the movable element by applying a magnet (37) to one of said legs; The method includes:

14. 14. The method for manufacturing a movable element according to claim 13, wherein the magnetized legs include two side legs (46, 47) and a central leg (45) between the two side legs, and magnetizing the legs is performed by applying the magnet only to the central leg.

15. 14. The method of manufacturing a movable element according to claim 13, wherein the magnet is a permanent magnet and the movable element is made of an annealed semi-hard ferromagnetic metal or a hard ferromagnetic metal.

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