CONTACT UNIT FOR AN IMPEDANCE LIMIT SWITCH

Description

[0001] This application claims priority from German patent application No. 10 2021 201 661.8, filed on February 22, 2021. Field of the invention

[0002] The invention generally relates to the field of electrical contacting in a measuring device. In particular, the invention relates to a contacting unit for an impedance limit switch, an impedance limit switch with such a contacting unit, and the use of such a contacting unit. background

[0003] Numerous electrical contacts are required inside or outside a field device or sensor, serving a variety of purposes. Electrical contact can be established using plugs and sockets. Furthermore, flexible cables, for example, can be used in laser technology and / or measurement technology, usually in conjunction with ribbon cables.

[0004] DE 10 2011 004 807 A1 relates to a probe unit with a coaxial design, at least in sections. In particular, the invention relates to a probe unit for a device for the capacitive or conductive determination of at least one process variable of a medium in a container. The process variable is, for example, the fill level and / or the electrical conductivity and / or the permittivity of the medium. Summary of the invention

[0005] It is an object of the present invention to provide a contacting unit for an impedance limit switch which enables high electrical contact reliability.

[0006] This object is achieved by the features of the independent patent claims. Further developments of the invention emerge from the subclaims and the following description of embodiments.

[0007] A first aspect of the present disclosure relates to a contacting unit for an impedance limit switch, which is configured to establish electrical contact between at least one contact surface of a printed circuit board and at least one electrode of the impedance limit switch. The contacting unit comprises a printed circuit board with an electrically conductive contact surface, a radially arranged annular spring for establishing electrical contact between the contact surface of the printed circuit board and the electrode of the impedance limit switch, and a non-conductive housing element.

[0008] The circuit board can be an electronic contacting board, an electronic assembly, or any carrier of electronic components. It should be noted that the contacting unit can have multiple circuit boards. The circuit board can, for example, further have a socket unit and / or a pin unit so that the circuit board can be connected to an electronic unit via them. The circuit board can have electronic components. Apart from the contact surface, the circuit board can be made of plastic. The contact surface can generally be any surface that can be conductive in contact or in contact with the annular spring. By establishing an electrical contact, an electrical circuit can thus be created.

[0009] The annular spring can be a donut-shaped and / or a solid torus-shaped spring. However, other geometries are also possible. The annular spring can be arranged radially or axially. It should be noted that multiple annular springs are also conceivable.

[0010] The impedance limit switch can be designed or configured to measure a limit level and / or a fill level of a container and / or a body of water and / or a storage facility. The impedance limit switch can measure any medium in any container. The impedance limit switch can be equipped with the necessary electronics to perform such measurements. The impedance limit switch can also be designed to be attached to a container.

[0011] Sensors such as impedance limit switches can be exposed to vibrations, so it can be advantageous to use a vibration-resistant electrical contact in such a sensor. A vibration-resistant electrical contact can, for example, prevent interruptions in the circuit. In this case, the circuit can be closed and / or guaranteed using the annular spring. By contacting multiple turns or windings and / or by using an annular spring to establish the electrical contact, greater contact reliability between the contact surface of the circuit board and the electrode can be achieved. The annular spring can offer radial and axial tolerance compensation. Thus, such a contact unit can, for example, reduce the sensitivity of an impedance limit switch to vibrations.

[0012] According to the invention, the contact surface of the circuit board is arranged at one of two opposing notches of the circuit board. Alternatively, the contact surface of the circuit board can be arranged at multiple notches of the circuit board. In other words, the contact surface of the circuit board can be arranged in such a way that the contact between the contact surface and the annular spring can be optimized.

[0013] According to one embodiment, the notches are arranged opposite one another in the radial direction of the circuit board and have a notch radius that corresponds to the cylinder radius of the annular spring. In other words, the notches can be designed such that they fit the outer contour of the annular spring as closely as possible, whereby the term "as closely as possible" is to be understood broadly in the context of the present application. This can increase the contact between the contact surface of the corresponding notch and the annular spring. The notches can also have other notch radii or geometries.

[0014] According to one embodiment, the housing element is configured to clamp the annular spring to the circuit board via its notch. For example, it is conceivable for the housing element to have a void or recess provided for this purpose. Such a void or recess can be arranged, for example, such that it or it can be opposite the contact surface of the circuit board. Thus, for example, the annular spring can be received in the void of the housing element or in a recess of the housing element, so that the annular spring can be held in optimal contact with the contact surface of the circuit board.

[0015] According to one embodiment, the contacting unit is designed to be plugged onto an electronics housing of the impedance limit switch. For this purpose, the housing element can, for example, have mechanical connecting devices and / or a plug-in mechanism. The term "plug-in" is to be understood broadly in the context of the present application. This can mean, for example, connecting, coupling, or clamping.

[0016] According to one embodiment, the electrode is a measuring probe, a shielding electrode, and / or a process connection. In other words, the contacted area can be part of a measuring electrode, a shielding electrode, and / or a process connection. This can also be a shielding element, which can, for example, protrude beyond the annular spring.

[0017] According to one embodiment, the shield electrode encloses, covers and / or encloses one or more ring springs.

[0018] According to one embodiment, the housing element is constructed in two parts and comprises a holder and an insert. The holder and insert are geometrically matched to one another, so that the insert can be snapped into the holder to accommodate and secure the annular spring. In other words, the housing element can be constructed as an assembly. A two-part housing element can be advantageous, for example, during assembly or disassembly of the contacting unit. For example, one or more annular springs can be attached to the holder and only subsequently secured by attaching or snapping the insert into the holder.

[0019] According to one embodiment, the housing element is rotationally symmetrical. A rotationally symmetrical housing can prove advantageous, for example, if the contact unit is attached to the impedance limit switch via a thread. It is also possible for the circuit board to be rotationally symmetrical as well.

[0020] According to one embodiment, the contact surface of the circuit board is coated with an electrically conductive material. Alternatively or additionally, the annular spring is coated with an electrically conductive material. The electrically conductive material can be ceramic, silver, copper, gold, and / or graphene. It can also be an alloy.

[0021] According to one embodiment, the housing element is made of plastic by means of an injection molding process.

[0022] According to one embodiment, the contacting unit comprises two or three concentrically arranged annular springs. Each of the two or three annular springs can be in electrical contact with different electrodes, measuring probes, and / or process connections.

[0023] According to one embodiment, the circuit board has two notches for each annular spring. The corresponding two notches are designed to provide electrical contact between the corresponding annular spring and the circuit board. Thus, for example, each annular spring can form a different circuit. It is conceivable, for example, that one annular spring is in contact with a contact surface of the circuit board and simultaneously in contact with a measuring probe. The second annular spring can, for example, be in contact with a contact surface of the circuit board and simultaneously in contact with a process connection.

[0024] According to one embodiment, the two or three concentrically arranged annular springs have different cylinder radii and / or different annular diameters. It should be noted that any number of annular springs is also conceivable. Thus, the different annular springs can be arranged at different locations on the circuit board and / or the contacting unit. The term "locations" can refer to an axial and / or radial position.

[0025] Another aspect of the present disclosure relates to an impedance limit switch. The impedance switch comprises a contacting unit, as described above and below, an electronics container, and a measuring head configured to perform a conductive and / or capacitive measurement and to acquire measurement data. The contacting unit is configured to forward the measurement data from the measuring head to the electronics container via the contacting unit.

[0026] Another aspect of the present disclosure relates to the use of a contacting unit, as described above and below, for forwarding measurement data from a measuring head via the contacting unit to an electronics can of a measuring device.

[0027] Embodiments of the present disclosure are described below with reference to the figures. Where the same reference numerals are used in the following description of the figures, they denote identical or similar elements. The representations in the figures are schematic and not to scale. Short description of the characters

[0028] Fig. 1 shows a contacting unit according to one embodiment. Fig. 2 shows a contacting unit according to a further embodiment. Fig. 3a and 3b show an impedance limit switch according to one embodiment. Fig. 4shows a contacting unit according to a further embodiment. Fig. 5a to 5e show a contacting unit according to a further embodiment. Fig. 6 shows an impedance limit switch according to another embodiment. Detailed description of embodiments

[0029] Figure 1 shows a contacting unit 100 according to an embodiment. In particular, Figure 1 a sectional view of a contact unit. The contact unit of the Figure 1 comprises a printed circuit board 102 with an electrically conductive contact surface 103, an electrically non-conductive housing element 110 and an annular spring 108. The annular spring 108 is arranged and designed such that it is used for electrical contact between the printed circuit board and an electrode 202 of an impedance limit switch (in Fig. 1not shown). For this purpose, the annular spring 108 can be coated with an electrically conductive material or even made of an electrically conductive material. For example, the annular spring 108 is gold-plated. The contact surface 103 of the circuit board 102 can also be coated with an electrically conductive material. Electrical contact thus takes place between the annular spring 108 and the contact surface 103 and between the annular spring 108 and the electrode 202. The annular spring 108 can be arranged in the contacting unit such that it surrounds the electrode 202. The housing element 110 can be made of plastic, for example, using an injection molding process. The housing element 110 is also designed such that it holds or clamps the annular spring 108 against the contact surface 103 of the circuit board 102. The contacting unit of the Figure 1enables a compact installation space, with simultaneous radial and axial tolerance compensation and electrical shielding.

[0030] Figure 2 shows a contacting unit 100 according to a further embodiment. Unless otherwise described, the contacting unit 100 of the Figure 2 the same elements and / or components as the contacting unit 100 of the Figure 1 The contacting unit 100 of the Figure 2 has three ring springs 108, 108', 108", each having a different cylinder radius and ring radius. The housing element 110 is in the embodiment of the Figure 2It is constructed in two parts and has a holder 104 and an insert 106. A two-part housing element 110 can, for example, simplify the attachment of the annular springs 108, 108', 108" during assembly of the contacting unit 100. Each annular spring 108, 108, 108' is in electrically conductive contact or in contact with a contact surface of the circuit board 102 (not visible here). As soon as the respective annular spring 108, 108', 108" is also in contact with an electrode 202 or with a process connection, an electrical circuit can be created. Thus, three electrical circuits can be formed with three annular springs.

[0031] Figures 3a and 3b show an impedance limit switch 200 according to an embodiment. In particular, Figures 3a and 3b two different sectional views of a part of an impedance limit switch 200. It should be noted that the electronics cup as well as the measuring head of the impedance limit switch 200 are in the Figures 3a and 3bare not shown. Unless otherwise described, the contacting unit 100 of the impedance limit switch of the Figures 3a and 3b the same elements and / or components as the contacting unit 100 of the Figures 1 and 2 The impedance limit switch 200 has a contacting unit 100, as described above and below. In addition, the impedance limit switch 200 can have a process connection 202", a shield electrode 202' and a measuring probe 202. The circuit board 102 has, in this embodiment, as shown in Figure 3b shown, a plurality of contact surfaces 103, 103', 103". The insert 106 of the housing element 110 is designed such that it fastens, clamps or holds the two annular springs 108', 108". The annular springs 108, 108', 108" are fastened, clamped or held such that a secure electrical contact is established and maintained between the respective contact surface 103, 103', 103" and the electrode 202, 202', 202".

[0032] Figure 4 shows a contacting unit according to an embodiment. In particular, Figure 4 a sectional view of a contacting unit. Unless otherwise described, the contacting unit 100 of the Figure 4 the same elements and / or components as the contacting unit 100 of the Figures 1 to 3 The circuit board 102 of the contacting unit 100 of the Figure 4also has a plurality of notches 402, 402'. Such notches 402, 402' can serve to better clamp the annular springs 108, 108', 108" onto the circuit board 102, in particular onto their contact surface 103, 103', 103". The notches 402, 402' are arranged opposite one another in the radial direction of the circuit board 102. The notches 402, 402' can also have a notch radius that corresponds to the cylinder radius of the corresponding annular spring 108, 108', 108'. In other words, the notches can have an outer contour that more or less corresponds to the outer geometry of the cylinder of the annular spring 108, so that the area of ​​the contact surface 103, 103', 103" that is in contact with the annular spring can be increased.

[0033] Figures 5a to 5e show a contacting unit 100 according to an embodiment. In particular, Figure 5aan exploded 3D view of the contact unit 100. Unless otherwise described, the contact unit 100 of the Figure 5 the same elements and / or components as the contacting unit 100 of the Figures 1 to 4The circuit board 102 may further include a socket unit 502, which may be configured to establish one or more electrical contacts between the contacting unit 100 and an electronics can of an impedance limit switch 200. The three ring springs 108, 108', 108", which are donut-shaped, have different cylinder radii and different ring radii. The housing 110 may include a void or recess such that one or more ring springs 108, 108', 108' can be received in such a void or recess. The housing element 110 may further include a connector device 506, which may be configured to unplug the contacting unit 100 from an electronics can of an impedance limit switch 200.Furthermore, the housing element 110, in particular the insert 106, can have an opening 504, which can be configured to receive a measuring probe 202 or an electrode 202.

[0034] Figure 6 shows an impedance limit switch 200 according to an embodiment. In particular, Figure 6 a 3D sectional view of an impedance limit switch 200 with a contacting unit 100. Unless otherwise described, the contacting unit 100 of the impedance limit switch of the Figure 6 the same elements and / or components as the contacting unit 100 of the Figures 1 to 5 Unless otherwise described, the impedance limit switch 200 of the Figure 6 the same elements and / or components as the impedance limit switch 200 of the Figure 4The shield electrode 202', also referred to as electrode, has, like the insert 106, an opening 504 which is configured to receive the measuring probe 202 in the contacting unit.

[0035] Additionally, it should be noted that "comprising" and "having" do not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. Furthermore, it should be noted that features or steps described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference signs in the claims are not to be considered limitations.

Claims

1. A contacting unit (100) for an impedance limit switch (200), arranged to establish an electrical contact between at least one contact surface (103) of a printed circuit board (102) and at least one electrode (202) of the impedance limit switch (200), comprising a printed circuit board (102) with at least one electrically conductive contact surface (103), and a non-conductive housing element (110), characterised in that a radially arranged annular spring (108) is provided for producing an electrical contact between the contact surface (103) of the printed circuit board (102) and the electrode (202) of the impedance limit switch (200), wherein the printed circuit board has two opposing notches, and wherein the contact surface (103) of the printed circuit board (102) is arranged on one of the two opposing notches (402) of the printed circuit board (102).

2. The contacting unit (100) according to claim 1, wherein the notches (402) are arranged opposite one another in the radial direction of the printed circuit board (102) and have a notch radius which corresponds to the cylindrical radius of the annular spring (108).

3. The contacting unit (100) according to any one of claims 1 or 2, wherein the housing element (110) is arranged to clamp the annular spring to the printed circuit board (102) via its notch.

4. The contacting unit (100) according to any one of the preceding claims, wherein the contacting unit (100) is designed to be plugged onto an electronic cup of the impedance limit switch (200).

5. The contacting unit (100) according to any one of the preceding claims, wherein the electrode is a measuring probe (202), a shield electrode (202') and / or a process connection (202").

6. The contacting unit (100) according to claim 5, wherein the shield electrode (202') encloses, covers and / or encases the one or more annular springs (108).

7. The contacting unit (100) according to any one of the preceding claims, wherein the housing element (110) is designed in two parts and has a holder (104) and an insert (106); wherein the holder (104) and the insert (106) are geometrically matched to one another, so that the insert (106) can be latched into the holder (104) in order to receive and fix the annular spring (108).

8. The contacting unit (100) according to any one of the preceding claims, wherein the housing element (110) is rotationally symmetrical.

9. The contacting unit (100) according to any one of the preceding claims, wherein the contact surface (103) of the printed circuit board (102) is coated with an electrically conductive material; and / or wherein the annular spring (108) is coated with an electrically conductive material.

10. The contacting unit (100) according to any one of the preceding claims, wherein the housing element (110) is of plastic by means of an injection moulding process.

11. The contacting unit (100) according to any one of the preceding claims, wherein the contacting unit (100) has two or three concentrically arranged annular springs (108, 108', 108").

12. The contacting unit (100) according to claim 11, wherein the printed circuit board has two notches (402, 402') for each annular spring (108, 108', 108"), and wherein the corresponding two notches (402, 402') are arranged to provide the electrical contact between the corresponding annular spring (108, 108', 108") and the printed circuit board (102).

13. The contacting unit (100) according to one of claims 11 and 12, wherein the two or three concentrically arranged annular springs (108, 108', 108") have different or identical cylinder radii and / or different ring diameters.

14. An impedance limit switch (200) comprising: a contacting unit (100) according to any one of claims 1 to 13; an electronic cup; and a measuring head which is configured to perform a conductive and / or capacitive measurement and to record measurement data; wherein the contacting unit (100) is configured to forward the measurement data from the measuring head to the electronic cup via the contacting unit (100).

15. Use of a contacting unit (100) according to any one of claims 1 to 13 for forwarding measurement data from a measuring head via the contacting unit (100) to an electronic cup of a measuring device.