Snap-action disc and snap-action disc arrangement

Abstract

The invention relates to a snap-action disc (10) for separately electrically contacting a plurality of contacts (20) which lie in a first plane and are insulated with respect to one another, wherein the snap-action disc (10) has a support body (11) for providing support on a surface lying in the first plane, a deformation body (12) connected thereto and a plurality of contact bridges (13) arranged spaced apart from the support body (11) on the deformation body (12) and insulated with respect to one another, wherein the deformation body (12) is designed to hold the contact bridges (13) in a non-deformed, stable state in a second plane spaced apart from the first plane and to be deformed resiliently in the direction of the first plane, by way of a force (K) acting from the second plane in the direction of the first plane, into a deformed, unstable or metastable state in which the contact bridges (13) lie in or on the first plane, wherein the contact bridges (13) are each designed, in the deformed state, to electrically connect at least two of the contacts (20) insulated with respect to one another.

Description

[0001] Snap dome and snap dome arrangement

[0002] Description:

[0003] The invention relates to a snap-action disc for the separate electrical contacting of a plurality of contacts and to a snap-action disc arrangement comprising such a snap-action disc.

[0004] Basically, snap domes have been known in the art for a long time, for example from document US 11,127,543 B2. A snap dome is usually understood to be a component for pushbutton switches which are intended to have a noticeable pressure point. For this purpose, these components are often made of spring steel or a similar material, whereby in the case of conventional snap domes it is important that their material and shape are such that they have a stable and a metastable state. The application of force can then bend the component and suddenly change from the stable to the metastable state, with the sudden state transition creating the aforementioned noticeable pressure point and usually an acoustic feedback that is perceptible as a "crack".

[0005] According to the prior art, it is provided that a snap disk is arranged in the push button switch on or above two contacts which are insulated from one another and which are electrically separated, i.e. insulated, in the stable state and contacted by the electrically conductive snap disk in the metastable state and are thus connected to one another.

[0006] The disadvantage here is that a snap-on disc can only represent one switch, meaning it can only establish a connection between exactly two contacts. Therefore, if several separately switchable connections are required, a pushbutton switch or snap-on disc must be provided for each, which is correspondingly space-intensive and costly.

[0007] Furthermore, in the state of the art it is usually not possible to detect whether an unintentional short circuit has occurred, so that it is not possible to distinguish whether the connection was established via the snap disk or by a faulty short circuit.

[0008] The invention is therefore based on the object of overcoming the aforementioned disadvantages and of providing a snap disk and an associated arrangement with which several separate switching signals can be generated in a fail-safe manner.

[0009] This problem is solved by the combination of features according to patent claim 1.

[0010] According to the invention, a snap-action disk is therefore proposed for separately electrically contacting a plurality of mutually insulated contacts located in a first plane. In the context of the present application, "insulated" is understood to mean electrically insulated. With regard to the contacts, it should be clarified that these are designed to be electrically insulated from one another, but can be electrically connected to one another by means of the contact bridges mentioned below. With regard to the contacts, the plurality of contacts preferably comprises at least three contacts, of which preferably exactly one contact is the collective contact explained below, and of which at least two contacts are the switching contacts explained below.According to the invention, the snap-action disc comprises a support body for support on a surface lying in the first plane, a deformation body connected thereto, and a plurality of contact bridges arranged on the deformation body at a distance from the support body and insulated from one another. The deformation body is designed to hold the contact bridges in an undeformed, stable state in a second plane spaced from the first plane and preferably correspondingly electrically separated from the contacts, and to be deformed resiliently in the direction of the first plane by a force acting from the second plane in the direction of the first plane into a deformed, unstable, or metastable state, in which the contact bridges lie in the first plane or border the first plane.Furthermore, the contact bridges are each designed to electrically connect at least two of the mutually insulated contacts in the deformed state of the deformed body, i.e., the unstable or metastable state, so that an electrical contact is established between at least two of the contacts by each contact bridge. This means that at least two of the contacts, together with the associated contact bridge, form a switch, and the one snap disk for each contact bridge can form a switch or serve as a switching element of a switch. With regard to the aforementioned collective contact and the aforementioned switching contacts, the collective contact preferably forms a switch with each switching contact, so that the number of switches or switching elements corresponds to the number of switching contacts.

[0011] The presently proposed snap-action disc, or its deformation body, is preferably designed such that the transition from the stable to the unstable or metastable state is sudden, i.e., the snap-action disc "snaps" from the stable to the metastable or unstable state as soon as the applied force reaches a limit. Depending on the selected material and the shape and embossing of the deformation body, this sudden transition can produce haptic feedback as a pressure point and acoustic feedback perceivable as a "crack."

[0012] Since the snap-in disc is intended to electrically connect several contacts, it is undesirable for an unintentional electrical connection to be established via the support body or the deformation body. Accordingly, various variants are provided to prevent such an unintentional electrical connection via the support and deformation bodies.

[0013] In a first variant, the support body and the deformation body are made of an electrically non-conductive material. Accordingly, an electrical connection can only be established via the contact bridges.

[0014] According to a second variant, the support body is made of an electrically conductive material and the deformation body is made of an electrically non-conductive material. Accordingly, the deformation body insulates the contact bridges from the support body. To prevent the support body from inadvertently electrically connecting the contacts already mentioned and explained in more detail below, an insulating separating body or an insulating layer can be provided between the support body and the contacts. Furthermore, the support body does not necessarily have to be supported on the contacts. The support body and / or contacts can be designed such that the support body has support points outside the contacts.It would also be possible for the support body to be designed to be supported on the contacts, but to have a segment for each support point, wherein the segments of the support body are in turn insulated from one another so that the contacts are not electrically connected via the support body.

[0015] A third variant provides that the support body is made of an electrically non-conductive material and the deformation body is made of an electrically conductive material, wherein the deformation body is insulated from the contact bridges, for example, by an intermediate separating body or an insulating layer, or the deformation body has a segment for each contact bridge, which are insulated from each other. In this variant, it can be provided that the deformation body and the contact bridges are formed integrally with each other, and each segment of the deformation body forms a contact bridge, wherein the segments are insulated from each other, for example, by a respective separating body or a respective insulating layer.

[0016] Furthermore, a fourth variant provides that the support body and the deformation body are made of an electrically conductive material, wherein the deformation body is insulated from the contact bridges, for example, by a separating body or an insulating layer, or the deformation body has a segment for each contact bridge, which are insulated from each other. As explained with regard to the second and third variants, the support body and / or the deformation body can be segmented, and the contact bridges can be formed, for example, integrally with the deformation body. Furthermore, it is also possible for a separating body or an insulating layer to be provided between the support body or its support points and the contacts.

[0017] The deformation body is preferably designed as a dome-shaped or frustoconical element, which is connected to the support body at its base. Accordingly, the support body can be arranged radially outward and the contact bridges radially inward on the deformation body, whereby the support body can extend around the deformation element.

[0018] The deformation body can also have an opening in the center, allowing the arrangement of a light source, such as an LED, centered in the snap-in disk. The light source can be electrically connected to one or even multiple contacts. In particular, the light source can be connected to the common contact, which preferably serves as a connection to GND.

[0019] The snap-action disc has connection sections on the support body, designed in particular as solder contacts, for attachment to a surface located in the first plane. The connection sections are preferably the aforementioned support or support points, by which the snap-action disc can be supported relative to the first plane or the surface located in the first plane.

[0020] A further aspect of the invention relates to a snap-action dome assembly comprising a snap-action dome according to the invention and a circuit carrier, which may be, for example, a printed circuit board. The circuit carrier has a surface defining the first plane, in or on which the plurality of mutually insulated contacts are arranged.

[0021] The plurality of contacts preferably consists of at least one collective contact and at least two switching contacts, so that the plurality of contacts comprises at least three contacts. The contact bridges are each designed to connect the collective contact to a switching contact. The number of switching contacts corresponds to the possible number of separately switchable connections.

[0022] The contacts, i.e., possibly both the collective contact and the switching contacts, are each web-shaped or formed with at least one and preferably a plurality of web-shaped sections and are arranged such that the web of a second contact, preferably one of the switching contacts, is arranged directly adjacent to a web of a first contact, preferably the collective contact. The contact bridges are each designed to connect the webs of two contacts, or at least one web of the collective contact to at least one web of a switching contact.

[0023] If corresponding collective contacts and switching contacts are provided and designed as webs or with web-shaped sections, it is further preferably provided that the collective contact is arranged centrally to an imaginary central axis and the switching contacts are distributed in the circumferential direction around the collective contact. The collective contact has at least one web per switching contact, with the webs of the collective contact extending radially outwards in a beam-like manner. In addition, it is provided that the webs of the switching contacts extend radially inwards, so that an annular overlap region is formed in the circumferential direction, in which at least one web of a switching contact is arranged directly adjacent to a web of the collective contact.

[0024] It is further provided that a snap-disk arrangement can further comprise a circuit for detecting an electrical connection between two contacts connectable by a contact bridge. Such a circuit comprises a voltage divider comprising a shunt resistor and a measuring resistor connected in series with one of the two contacts, as well as a voltage measuring device designed to measure the voltage across the measuring resistor, so that when contacts are contacted by the contact bridge, the voltage measuring device can measure a known voltage dependent on the measuring resistor, which indicates, i.e., indicates, an electrical connection between the contacts via the contact bridge.

[0025] With regard to a variant comprising a collective contact and a plurality of switching contacts, it is preferably provided that the snap disk arrangement has a circuit for detecting a respective electrical connection through a contact bridge between the collective contact and a switching contact. In this case, one measuring strand is provided for each switching contact. Alternatively, one measuring strand is provided for each switching contact group, wherein a switching contact group comprises at least one switching contact and wherein the switching contacts of a group are connected in parallel to one another or electrically conductively connected to one another. For each measuring strand, the circuit has a voltage divider comprising a shunt resistor and a measuring resistor, connected in series with the respective switching contact.In order to be able to detect an electrically conductive connection between the collective contact and a respective switching contact and preferably a short circuit intentionally created thereby, the circuit has at least one voltage measuring device with at least one measuring input, which is designed to measure the voltage across a measuring resistor at a respective measuring input, so that when the switching contact is electrically connected to the collective contact by the contact bridge, the voltage measuring device can measure a previously known voltage at the respective measuring input, which voltage is dependent on the respective measuring resistor and indicates an electrical connection between the collective contact and the respective switching contact via the contact bridge. Preferably, one voltage measuring device with one measuring input is provided for each measuring strand, although alternatively one voltage measuring device could also be provided for each measuring strand.

[0026] The voltage dividers can have measuring resistors and shunt resistors of identical size, so that when the respective switching contact is connected to the collective contact, an identical voltage is produced.

[0027] However, it is advantageous if the measuring resistors and the shunt resistors of the voltage divider have different values ​​from each other, so that an individual voltage is generated across each of the measuring resistors when the contacts are connected, each of which is assigned to a specific switching contact or switching contact group. Since this voltage is known in advance, the measured voltage can be compared as the actual voltage with the stored, known voltage as the target voltage, thus determining whether a faulty short circuit or an intended connection is present.

[0028] For the evaluation of the measured voltages, the voltmeter device can further be designed as a control unit or connected to a control unit. If multiple voltage measuring devices are provided, each of them can be connected to the control unit. The control unit is designed to compare the voltages measured across the measuring resistors as actual voltages with the voltages assigned to the respective measuring strands as target voltages.

[0029] Furthermore, one aspect of the invention relates to a pushbutton switch with a snap-action disk according to the invention and / or a snap-action disk arrangement according to the invention, wherein the pushbutton switch further comprises a pushbutton body for transmitting the force to the snap-action disk. The pushbutton body is designed to transmit a force to the snap-action disk in such a way that the contact bridges can be brought from the second plane to the first plane and the deformation body can be deformed accordingly. Furthermore, the pushbutton body is preferably also designed such that the transmitted force can be varied with regard to its point of action at which the force is applied to the snap-action disk, so that, for example, the contact bridges can be brought into contact with the contacts individually and independently of one another.

[0030] The features disclosed above can be combined as desired, as long as this is technically possible and they do not contradict each other.

[0031] Other advantageous developments of the invention are characterized in the subclaims or are presented in more detail below, together with the description of the preferred embodiment of the invention, with reference to the figures. They show:

[0032] Fig. 1 shows a snap disk arranged on contacts of a circuit carrier;

[0033] Fig. 2 contacts of a circuit carrier;

[0034] Fig. 3 shows a first variant of a snap disk arrangement;

[0035] Fig. 4 a second variant of a snap disk arrangement.

[0036] The figures are schematic examples. Identical reference numerals in the figures indicate identical functional and / or structural features. The contacts according to Figure 2 can in particular be the contacts shown in Figure 1. Furthermore, the contacts according to Figures 1 and 2 can correspond to the contacts according to Figures 3 and 4, wherein a snap disk according to Figure 1 can be provided on the snap disk arrangement according to Figures 3 and 4. A main idea of ​​the present invention is to be able to generate several separate switching signals with just one snap disk, so that accordingly several connections between contacts can be established, preferably independently of one another, with just one snap disk.

[0037] For this purpose, a snap-action disc 10 is proposed, as shown by way of example in Figure 1. The snap-action disc 10 is segmented for this purpose, so that an electrically conductive connection is not established simultaneously between all connectable contacts 20, 21, 22, 23, 24, 25. However, the segmentation can be achieved using different variants. Basically, the snap-action disc 10 comprises a support body 11, a deformation body 12, and several contact bridges 13, the latter being designed to establish the electrically conductive connection between the respective contacts 20, 21, 22, 23, 24, 25 to be connected.

[0038] From the stable state of the snap-action disc 10 shown in Figure 1, if an applied force K exceeds a limit force, the disc can be brought into a metastable or unstable state in which the contact bridges 13 are deflected towards the contacts 20, 21, 22, 23, 24, 25. Depending on the area or segment of the snap-action disc 10 to which the force K is applied, only one or only certain contact bridges 13 are in contact with the respective associated contacts 20, 21, 22, 23, 24, 25. In the present example, five contacts 20 are provided, which are designed as a collective contact 25 and four switching contacts 21, 22, 23, 24. The collective contact 25 can be connected to the switching contacts 21, 22, 23, 24 by means of a switching bridge 13, so that four separate switches or connections can be realized.Depending on the position and / or the area of ​​the applied force K, either only one connection or several connections can be established.

[0039] To support the snap-action disc 10 on the surface defined by the contacts 20, 21, 22, 23, 24, 25, the latter also forms a plurality of connection sections 14 on the support body 11, evenly distributed in the circumferential direction. If the snap-action disc is supported directly on the contacts 20, 21, 22, 23, 24, 25, as shown in Figure 1, and if at least the support body 11 is made of an electrically conductive material, it is important that the connection sections 14 are insulated from one another or that the snap-action disc 10 as a whole is insulated from the contacts 20, 21, 22, 23, 24, 25. For this purpose, for example, an insulating layer can be applied to the side of the support body 11 facing the contacts 20, 21, 22, 23, 24, 25 or the support body 11 can be divided into insulated segments.

[0040] As shown in detail in Figure 2, the collective contact 25 is arranged centrally and the switching contacts 21, 22, 23, 24 are distributed around it, wherein both the collective contact 25 and the switching contacts 21, 22, 23, 24 form web-shaped sections 26 or webs 26. The webs 26 of the collective contact 25 extend radially outwards in a beam shape and the webs 26 of the switching contacts 21, 22, 23, 24 extend radially inwards, wherein between each two webs 26 of the collective contact 25 there is a web 26 of a switching contact 21, 22, 23, 24 so that they overlap in the circumferential direction in an annular contact area. If a contact bridge 13 or several contact bridges 13 are pressed against the surface, the electrical contact between the collective contact 25 and the respectively assigned switching contact 21, 22, 23, 24 is established accordingly in the annular contact area via the webs 26.If it is now to be detected whether and which connection is closed, a snap disk arrangement according to Figures 3 and 4 provides a circuit 30 each.

[0041] In addition to the connection of the circuit 30 to the contacts 21, 22, 23, 24, 25 according to Figures 1 and 2, a partial equivalent circuit diagram (40) is also shown.

[0042] The circuit 30 according to Figure 3 provides that a measuring branch, each with a voltage divider consisting of a shunt resistor R1-R4 and a measuring resistor R5-R6, is provided for each switching contact 21, 22, 23, 24. The voltage present at the measuring resistor R5-R6 is determined by means of the voltage measuring device. The voltage measuring device 35, which is designed as a control unit in this case, has an input 31-34 for each measuring branch, so that the respective voltage present at the measuring resistor R5-R6 can be detected.

[0043] Different sizes or resistance values ​​are provided for the shunt resistors R1 - R4 and the measuring resistors R5 - R6, so that when a connection is closed between the respective switching contact 21 - 24 and the common contact 25, an individual voltage is generated that can be assigned to the connection. By measuring the voltage as the actual voltage by the voltage measuring device 35 and comparing it with the assigned voltage stored for this purpose, it can be determined whether the connection is closed by the contact bridge. If a voltage is measured that is not or cannot be assigned to a connection, a faulty short circuit is present.

[0044] The variant according to Figure 4 essentially corresponds to the embodiment of Figure 3. However, if fewer possible or producible connections are required, the switching contacts 21 - 24 can be combined into switching contact groups, in which case an evaluation of the switching contact groups is sufficient. Accordingly, two switching contact groups are provided in Figure 4, with each switching contact group having two interconnected switching contacts 21 - 24. A first switching contact group therefore comprises the switching contacts 21, 23 that are in contact with one another, and a second switching contact group comprises the switching contacts 22, 24 that are in contact with one another. A measuring strand is each assigned to each switching contact group, whereby a voltage measuring device 35 with two inputs 31, 32 is sufficient.If a connection is established between the collective contact 25 and one of the switching contacts 21, 23 via the respective contact bridge 13, this can be detected via the first input 31. If a connection is established between the collective contact 25 and one of the switching contacts 22, 24, this can be detected via the second input 32.

[0045] The invention is not limited to the preferred embodiments described above. Rather, a number of variants are conceivable that utilize the presented solution even in fundamentally different embodiments.

Claims

Patent claims 1. Snap-action disc (10) for separately electrically contacting a plurality of contacts (20) located in a first plane and insulated from one another, wherein the snap-action disc (10) has a support body (11) for support on a surface located in the first plane, a deformation body (12) connected thereto, and a plurality of contact bridges (13) arranged on the deformation body (12) at a distance from the support body (11) and insulated from one another, wherein the deformation body (12) is designed to hold the contact bridges (13) in an undeformed, stable state in a second plane spaced from the first plane and to be deformed elastically in the direction of the first plane by a force (K) acting from the second plane in the direction of the first plane into a deformed, unstable, or metastable state, in which the contact bridges (13) lie in or on the first plane, wherein the contact bridges (13) are each designed,to electrically connect at least two of the mutually insulated contacts (20) in the deformed state., 2. Snap-action disc according to claim 1, wherein the support body (11) and the deformation body (12) are made of an electrically non-conductive material or wherein the support body (11) is made of an electrically conductive material and the deformation body (12) is made of an electrically non-conductive material or wherein the support body (11) is made of an electrically non-conductive material and the deformation body (12) is made of an electrically conductive material, wherein the deformation body (12) is insulated from the contact bridges (13) or the deformation body (12) each contact bridge (13) is divided into a segment, which are insulated from each other, or wherein the support body (11) and the deformation body (12) are made of an electrically conductive material, wherein the deformation body (12) is insulated from the contact bridges (13) or the deformation body is divided into one segment per contact bridge (13), which are insulated from one another.

3. Snap-action disc according to claim 1 or 2, wherein the deformation body (12) is designed as a dome-shaped or frusto-conical element which is connected at its base to the support body (11).

4. Snap-action disc according to one of the preceding claims, wherein connecting sections (14) are provided on the support body (11) for fastening to a surface lying in the first plane.

5. Snap-on disk arrangement with a snap-on disk (10) according to one of the preceding claims and a circuit carrier, wherein the circuit carrier has a surface defining the first plane, in or on which the plurality of mutually insulated contacts (20) are arranged.

6. Snap disk arrangement according to the preceding claim, wherein the plurality of contacts consists of at least one collective contact (25) and at least two switching contacts (21, 22, 23, 24) and wherein the contact bridges (13) are each designed to connect the collective contact (25) to a respective switching contact (21, 22, 23, 24).

7. Snap-action disk arrangement according to one of the two preceding claims, wherein the contacts (20) are each web-shaped or have web-shaped sections (26) and are arranged such that the web (26) of a second contact is arranged immediately adjacent to a web (26) of a first contact, wherein the contact bridges (13) are each designed to connect webs (26) of two contacts (20) to one another.

8. Snap-action disk arrangement according to the two preceding claims, wherein the collective contact (25) is arranged centrally to an imaginary central axis and the switching contacts (21, 22, 23, 24) are arranged distributed in the circumferential direction around the collective contact (25), wherein the collective contact (25) has at least one web (26) for each switching contact (21, 22, 23, 24) and the webs (26) of the collective contact (25) extend radially outwards in a beam-like manner, wherein the webs (26) of the switching contacts (21, 22, 23, 24) extend radially inwards, so that an annular overlap region is formed in the circumferential direction, in which a web (26) of a switching contact (21, 22, 23, 24) is arranged directly adjacent to a web (26) of the collective contact (25).

9. Snap-action disk arrangement according to one of claims 5 to 8, further comprising a circuit (30) for detecting an electrical connection between two contacts (20, 21, 22, 23, 24, 25) connectable by a contact bridge (13), wherein the circuit comprises a voltage divider connected in series with one of the two contacts (20, 21, 22, 23, 24, 25) comprising a shunt resistor (R1, R2, R3, R4) and a measuring resistor (R5, R6, R7, R8) as well as a voltage measuring device (35), which is designed to measure the voltage across the respective measuring resistor (R5, R6, R7, R8), so that when contacts (20, 21, 22, 23, 24, 25) are contacted by the contact bridge (13), the voltage measuring device (35) can measure a previously known voltage which is dependent on the measuring resistor (R5, R6, R7, R8), and which indicates an electrical connection between the contacts (20, 21, 22, 23, 24, 25) via the contact bridge (13).

10. Snap-action disk arrangement according to one of claims 6 to 8, further comprising a circuit (30) for detecting a respective electrical connection through a contact bridge (13) between the collective contact (25) and a switching contact (21, 22, 23, 24), wherein one measuring strand is provided for each switching contact (21, 22, 23, 24) or one measuring strand is provided for each switching contact group, which has at least one switching contact (21, 22, 23, 24), wherein the switching contacts (21, 22, 23, 24) of a switching contact group are electrically connected to one another, wherein the circuit (30) for each measuring strand has a voltage divider connected in series with the respective switching contact (21, 22, 23, 24) comprising a shunt resistor (R1, R2, R3, R4) and a measuring resistor (R5, R6, R7, R8), and wherein the circuit (30) has at least one voltage measuring device (35) with at least one measuring input (31, 32, 33, 34), which is designed to measure the voltage via a measuring resistor (R5, R6, R7,R8) at a respective measuring input (31, 32, 33, 34), so that when the switching contact (21, 22, 23, 24) is electrically connected to the collective contact (25) by the contact bridge (13), a previously known voltage dependent on the respective measuring resistor (R5, R6, R7, R8) can be measured by the voltage measuring device (35) at the respective measuring input (31, 32, 33, 34), which voltage creates an electrical connection between the collective contact, (25) and the respective switching contact (21, 22, 23, 24) via the contact bridge (13).

11. Snap-action disk arrangement according to the preceding claim, wherein the voltmeter device (35) is designed as a control unit or is connected to a control unit and wherein the control unit is designed to compare the voltages measured via the measuring resistors (R5, R6, R7, R8) with voltages respectively assigned to the measuring strands.

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