Patent Description:
Conventionally, switching devices utilize a mechanically controlled contacts that wear out after a given number of operations and limit a longevity of the switching devices. Furthermore, such switching devices are not suitable for an operation in a humid environment because the mechanically controlled contacts would be exposed to the entry of humidity and degrade prematurely.

With a progress of technology, the mechanical controlled contacts of the switching devices have been gradually replaced by contactless solid-state switches controlled by a magnetic or an electrical field. An example of contactless solid-state switches controlled by a magnetic field can be found for instance in <CIT> or <CIT>. In some cases, such contactless solid-state switches utilize a permanent magnet to provide a source of a magnetic field for switching control. An utilization of traditional permanent magnets as a source of a magnetic field in mid to high volume production of switching devices bears manufacturing disadvantages caused by challenges in handling and assembly of permanent magnets that drives overall product cost.

Therefore, it would be advantageous to have a simple, low-cost contactless switching device that is easy to manufacture.

One aspect of the present disclosure is directed to an electrical contactless switch as defined in claim <NUM>.

A further aspect of the present disclosure is directed to a method of manufacturing a moveable element for the electrical contactless switch as defined in claim <NUM>.

Further areas of applicability will become apparent from the description herein. The description and specific examples in the summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

Other features and advantages of the invention appear from the following detailed description of some of its embodiments, given by way of non-limiting example, and with reference to the accompanying drawings, in which:.

As used herein, an element or step recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural of the elements or steps, unless such exclusion is explicitly stated. Further, references to "one embodiment" are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments "comprising" or "having" an element or a plurality of elements having a particular property may include additional elements not having that property.

In the figures, the same references denote identical or similar elements, unless stated otherwise. In the drawings, the size of each element or a specific portion constituting the element is exaggerated, omitted, or schematically shown for convenience and clarity of description. Thus, the size of each component may not entirely reflect the actual size. In the case where it is judged that the detailed description of the related known functions or constructions may unnecessarily obscure the gist of the present disclosure, such explanation will be omitted.

In <FIG> is depicted a first embodiment of an electrical contactless switch <NUM>. The first embodiment comprises a housing <NUM>, a moveable element <NUM> and a magnetic field sensor <NUM>. The moveable element moves relative to the housing between a resting position and an engaged position as depicted by an arrow <NUM>. The moveable element may slidably move in a slot <NUM>, <NUM> within the housing <NUM>. The moveable element <NUM> may have a plurality of magnetized protrusions that may form a plurality of magnetized legs <NUM> and <NUM> spaced from each other by having a gap <NUM> therebetween. Whilst there are two legs of the plurality of magnetized legs depicted in <FIG>, the moveable element <NUM> may have three or more legs. The magnetized legs <NUM> and <NUM> may protrude in parallel from one side of the moveable element <NUM>. The magnetic field sensor <NUM> is secured to the housing and positioned to face the plurality of magnetized legs <NUM> and <NUM>. The magnetic field sensor <NUM> may be coupled to a printed circuit board <NUM> that may be attached (not shown) to the housing <NUM>. The magnetic field sensor <NUM> detects a magnetic field generated by the plurality of magnetized legs <NUM>, <NUM> as the moveable element <NUM> is in the engaged position. The moveable element <NUM> is closer to the magnetic field sensor <NUM> in the engaged position than in the resting position. The magnetic field sensor <NUM> may comprise a Hall-effect or a magneto resistive sensor. The magnetic field sensor <NUM> may be a Hall-effect switch. The moveable element is elastically biased towards the resting position via a resilient element <NUM> that may be positioned at least partially between the plurality of magnetized legs <NUM> and <NUM> and the magnetic field sensor <NUM>. The resilient element <NUM> counteracts a movement of the moveable element from the resting position to the engaged position. The resilient element <NUM> may be made of an elastomer and have variety of shapes.

<FIG> depict a second embodiment of the electrical contactless switch <NUM>, <NUM>. <FIG> depicts the second embodiment of the electrical contactless switch <NUM> in an engaged position and <FIG> depicts the second embodiment of the electrical contactless switch <NUM> in a resting position. The second embodiment comprises a housing <NUM>, a moveable element <NUM> and a magnetic field sensor <NUM>. The moveable element moves relative to the housing between a resting position and an engaged position as depicted by an arrow <NUM>. The moveable element <NUM> may have a plurality of magnetized protrusions that may form plurality of magnetized legs <NUM>, <NUM> and <NUM> spaced from each other by having a gap therebetween. The moveable element <NUM> as depicted in <FIG> has three legs, however, the moveable element may have other number of legs than three. The magnetized legs <NUM>, <NUM> and <NUM> may protrude in parallel from one side of the moveable element <NUM>. The moveable element <NUM> may have two side legs <NUM>, <NUM> and a middle leg <NUM> located between the two side legs. Each of the two side legs <NUM>, <NUM> may be terminated by a hook <NUM> and <NUM> protruding laterally outwards as depicted in <FIG>. The housing <NUM> may have a slot <NUM>, <NUM> in which the moveable element <NUM> is slidably guided. The side legs <NUM> and <NUM> may be snap-fitted in the slot and maintained in the slot by the hooks <NUM>, <NUM> cooperating with an abutment <NUM>, <NUM> belonging to the slot.

The magnetic field sensor <NUM> is secured to the housing and positioned to face the plurality of magnetized legs <NUM>, <NUM> and <NUM>. The magnetic field sensor <NUM> may be coupled to a printed circuit board <NUM> that may be attached (not shown) to the housing <NUM>. The magnetic field sensor <NUM> may detect a magnetic field generated by the plurality of magnetized legs <NUM>, <NUM> and <NUM> as the moveable element <NUM> is in the engaged position <NUM>. The moveable element <NUM> may be closer to the magnetic field sensor <NUM> in the engaged position which is depicted as a gap <NUM> than in the resting position. The magnetic field sensor <NUM> may comprise a Hall-effect or a magneto resistive sensor. The magnetic field sensor <NUM> may be a Hall-effect switch.

There may more than one magnetic sensor secured to the housing to provide redundancy in sensing of the magnetic field generated by the plurality of magnetized legs <NUM>, <NUM> and <NUM> as the moveable element <NUM> is in the engaged position <NUM>. For instance, an additional magnetic sensor <NUM> may be coupled to the same printed circuit board <NUM>. The printed circuit board <NUM> may be a single or a double-sided printed circuit board <NUM> and the magnetic sensor <NUM> may be soldered to a one side of the printed circuit board <NUM>. The additional magnetic sensor <NUM> may be advantageously coupled to the opposite side of the printed circuit board <NUM> than a first magnetic sensor <NUM>. The both magnetic sensors <NUM>, <NUM> may be placed at substantially same location having only the printed circuit board in between so that they both detect a magnetic field generated by the plurality of magnetized legs <NUM>, <NUM> and <NUM> as the moveable element <NUM> moves to the engaged position <NUM>. The both magnetic sensors may comprised of identical sensors or they may be comprised of different types of sensors for instance a Hall effect and a magneto resistive sensor.

The printed circuit board <NUM> may bear other electronic components <NUM> such as without limitation processing and or protecting circuitry, communication and/or connecting circuitry and so forth.

The moveable element <NUM> is elastically biased towards the resting position via a resilient element <NUM> that may be positioned at least partially between the plurality of magnetized legs <NUM>, <NUM> and <NUM> and the magnetic field sensor <NUM>. The resilient element <NUM> may counteract a movement of the moveable element from the resting position to the engaged position. The resilient element <NUM> as depicted in <FIG> may be a compression type coil spring. However, other types of resilient elements may be used. A non-limiting example of such resilient element may be an elastomer having variety of shapes, leaf spring, volute spring, extension spring and so forth.

The moveable element <NUM> is made from a ferromagnetic material. The ferromagnetic material is a metal. The metal is a semi-hard or hard ferromagnetic metal. The metal may be made from a cobalt based metal. The moveable element <NUM> may be initially not magnetized. The semi-hard or hard ferromagnetic metal may be selected from materials having a coercivity Hc e.g. between <NUM> to <NUM> A/m. The ferromagnetic material may be in the shape of a metal sheet or metal plate. The ferromagnetic material may be ductile and suitable for producing the moveable element by a stamping or punching from the metal sheet or the metal plate. One benefit of such type of production is a low-cost production of the moveable element. Another benefit of such production is that the moveable element when punched from not magnetized metal sheet which simplifies its transport and handling. In general, ductile relates to a material property expressing a capacity to sustain and/or withstand plastic deformation.

When made of the metal sheet or the metal plate the moveable element <NUM> forms a plate shape with a thickness comprised between of <NUM> to <NUM> as depicted in <FIG> that shows an exemplary perspective view of such a plate shape <NUM> moveable element <NUM>. Stamping or punching method enables a production of features such as for instance protrusions <NUM> terminating legs of the moveable element <NUM>. The moveable element may also be made by an alternative method for instance from powder pressed metal via for instance metal injection molding or other methods involving different types of metal additive or metal subtractive manufacturing.

Once the moveable element <NUM> is shaped a heat treatment may be performed. The heat treatment may be an annealing. One benefit of annealing may be is that it makes the ferromagnetic material of the moveable element <NUM> harder than before annealing and in annealed state the ferromagnetic material of the moveable element <NUM> may exhibit well defined, robust and repeatable magnetic properties.

<FIG> and <FIG> depict an exemplary magnetization process of the moveable element <NUM> as described in either of the two embodiments. <FIG> depict the moveable element <NUM> being initially in an unmagnetized condition and a source of magnetic field <NUM> that may be formed by a permeant magnet <NUM>. Alternatively, the source of magnetic field may be an electromagnet (not shown). The permanent magnet <NUM> may have a magnetic South pole on its first end <NUM> and magnetic North pole on its second end opposite to the first end <NUM>.

The first end <NUM> of the permanent magnet <NUM> may be set to face an end <NUM> of the middle leg <NUM> of the moveable element <NUM>. As depicted in <FIG> the first end <NUM> of the permanent magnet may be moved in the direction of arrow <NUM> in <FIG> towards the end <NUM> of the middle leg <NUM> of the moveable element <NUM> until the first end <NUM> of the permanent magnet <NUM> becomes abutted against the end <NUM> of the middle leg of the moveable element <NUM>. The moveable element <NUM> consequently may become magnetized by the permanent magnet magnetic field <NUM> generated by the permanent magnet <NUM>. One benefit of such magnetizing operation is in its simplicity and ability to be turned into an automatic industrial process.

The magnetizing of the legs may be performed by abutting <NUM> the magnet against the middle leg only. Then the magnetic lines may travel through the side legs <NUM>, <NUM> of the moveable element <NUM> and close the magnetic circuit through the middle leg <NUM> of the moveable element <NUM>. Hence, the middle leg <NUM> of the magnetized moveable element <NUM> may become magnetized in an opposite direction than the side legs <NUM>, <NUM> of the magnetized moveable element <NUM>. Provided the first end <NUM> of the permanent magnet bears a South magnetic pole as depicted in <FIG> then the middle leg <NUM> of the magnetized moveable element <NUM> may become magnetized as a North magnetic pole and the side legs as having a South magnetic pole.

<FIG> depicts magnetic field lines that may be produced when the moveable element <NUM> is magnetized, as described above, by abutting <NUM> the permanent magnet <NUM> against the middle leg <NUM> of the moveable element <NUM> only. The magnetic field lines <NUM> may then flow from the middle leg <NUM> of the magnetized moveable element <NUM> to the side legs <NUM> and <NUM>. The magnetic force lines flowing through the gaps <NUM>, <NUM> between the middle leg <NUM> and each of the side legs <NUM>, <NUM> of the moveable element <NUM> may be denser than the magnetic field lines <NUM> that close between middle leg <NUM> and each of the side leg <NUM>, <NUM> through the magnetic field sensor <NUM>.

One benefit of such flat and focused shape of the movable element 48is that it enables to design a compact size yet robust electrical contactless switch.

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the various embodiments of the disclosure without departing from their scope. While the dimensions and types of materials described herein are intended to define the parameters of the various embodiments of the disclosure, the embodiments are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the various embodiments of the disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein. " Moreover, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

Claim 1:
Electrical contactless switch (<NUM>, <NUM>, <NUM>) comprising:
a housing (<NUM>, <NUM>);
a resilient element (<NUM>, <NUM>);
a moveable element (<NUM>, <NUM>) made of a semi-hard or a hard ferromagnetic metal material and slidably mounted in the housing, wherein the moveable element has a plate shape with a thickness of <NUM> to <NUM> and is adapted to move relative to the housing between a resting position and an engaged position, the moveable element being elastically biased towards the resting position, wherein the moveable element comprises a plurality of magnetized legs (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) spaced from each other and at least part of the magnetized legs is slidably guided in the housing;
a magnetic field sensor (<NUM>, <NUM>) secured to the housing and positioned to face the plurality of magnetized legs, the magnetic sensor is configured to detect a magnetic field generated by the magnetized legs as the moveable element is in the engaged position, wherein the moveable element is closer to the magnetic field sensor in the engaged position than in the resting position, wherein the resilient element is positioned at least partially between the plurality of magnetized legs and the magnetic field sensor, wherein the resilient element is configured to elastically bias the moveable element towards the resting position and counteract a movement of the moveable element from the resting position to the engaged position.