Patent Application
20070290777
The invention relates to an electrical switch device according to the preamble of claim 1.
A switch device of this type is described in DE 101 03 814 A1. The switch device serves in particular for switching off a current line for a high frequency reference line via various damping elements. For this purpose, it has an oblong switch element which is movable transversely relative to its longitudinal direction by means of a displacement element and, with a contact surface at its one end, is thereby optionally brought out of contact or in contact with a counter-contact surface. In the contact position, the line of the electrical current to the contact surfaces is dependent inter alia upon the mutual abutment of the contact surface and counter-contact surface. Contaminants or particles can substantially damage the current line, in particular when the contaminants or particles comprise electrically non-conducting material.
An interference-free current line is particularly important with reference lines which serve for damping adjustment, e.g. of signal generators or network analysers. Reference lines have for example a plurality of serially arranged, four-pole switch devices with, on the input and output side, the same and constant characteristic wave impedance and also respectively adjustable calibrated damping.
In the case of known electrical high frequency switch devices, as are used for example typically in high frequency reference lines, the lateral switch movement of a switch element is achieved by means of an external mechanical force effect by means of tappets which strike laterally against the switch element and thereby move it. On the basis of the lateral pivot movement which the switch element performs and the linear thrust movements of the tappets which are present on both sides of the switch element, sliding movements which lead to abrasion material on the basis of the resulting friction are produced in the contact region of the tappets and the switch element. In particular when the switch device has a closed switching space, the danger of contact interference due to abrasion material produced by the friction is particularly high because the abrasion material remains in the switching space. However even in the case of an open switching space, the danger exists that the abrasion material enters between the contact surfaces and impairs the electrical contact.
The object underlying the invention is to eliminate or at least to reduce friction processes in the case of an electrical switch device of the initially indicated type and the danger resulting therefrom of damage to the electrical contact due to abrasion material. In particular, the occurrence of abrasion material in the surroundings of the contact surfaces is intended to be avoided or at least reduced. In addition, a simple and also compact construction is intended to be produced, which can be integrated well and also in a simple and economical manner not only in the switch device but also in or on a protective housing which receives the switch device.
This object is achieved by the features of claim 1. Further developments of the invention are described in the sub-claims.
The knowledge underlying the invention is that, in the case of a switch movement drive of the switch element with magnetic forces, there is no requirement for a mechanical movement contact between the switch element and the displacement elements and therefore, in the case of switch movements of the switch element which are produced with magnetic forces, in this respect no sliding friction takes place nor is abrasion material resulting therefrom produced.
In the case of the switch device according to the invention, the switch element comprises at least partially magnetic material and the displacement elements are formed by two magnet arrangements, of which the magnetic force of the one magnet arrangement or also the magnetic force of the other magnet arrangement is or are respectively optionally reducible or increasable. As a result, the switch device can be switched by reducing or increasing the magnetic force such that the laterally movable switch element is moved either towards the counter-contact element which is disposed on the one side and is retained thereon or is moved towards the counter-contact element disposed on the other side and is retained. This movement drive is effected without contact and without friction so that abrasion material, as occurs in the state of the art, is avoided and therefore any impairment resulting therefrom to the electrical contact is avoided and a good electrical contact is ensured. The invention is therefore characterised by a simple and compact construction which can be produced also economically and can be readily integrated not only in the switch device itself but also in a protective housing which surrounds the switch device.
In the case of the invention, a magnetic force difference between the magnet arrangements is produced by reducing or increasing the magnetic force of a lateral magnet arrangement or both magnet arrangements, said difference being so large that respectively the magnet arrangement with the greater magnetic force is able to draw the switch element towards itself and towards the counter-contact element situated on the same side and to retain it thereon. Release from the counter-contact element can then be effected in that the magnetic force of the magnet arrangement which retains the switch element on the adjacent counter-contact element is reduced so far that the magnetic force of the oppositely situated magnet arrangement predominates and releases the switch element and draws it towards this magnet arrangement and makes contact with the counter-contact element situated on this side, or the magnetic force of this oppositely situated magnet arrangement is increased so far that this magnetic force releases the switch element and moves it to this side and makes contact with the counter-contact element situated on this side.
Within the scope of the invention, it is thereby unnecessary that magnet arrangements with reducible or increasable magnetic forces need be present on both sides. Within the scope of the invention, it suffices if a magnet arrangement is present on one side, the magnetic force of which is reducible or increasable in order to release the switch element from the oppositely situated counter-contact element and to draw it towards the counter-contact element which is disposed on its side or vice versa.
Reducing or increasing the magnetic force can be achieved in that an electromagnet is provided, which can optionally be switched on and switched off or the magnetic force of which is reducible or again increasable. The sought magnetic force change can however also be achieved in that an electromagnet and a permanent magnet are combined in an essentially coaxial arrangement, the permanent magnet being able to form an extension of the core of the electromagnet or being able to form the core of the electromagnet. This embodiment leads not only to a compact construction but also makes it possible to superimpose the magnetic force of the permanent magnet in the sense of an addition or subtraction of the magnetic forces due to a homopolar or antipolar arrangement of the electromagnet and of the permanent magnet. It is thereby particularly advantageous to configure the electromagnet to be pole-changing so that the magnetic force change can be altered by addition and subtraction of the magnetic forces. If the electromagnet is in addition also still configured able to be switched off, a threefold change in the respective magnetic force can be achieved.
It is furthermore advantageous to provide respectively one permanent magnet with a magnetic force which is so great that the electromagnet can be switched off directly after contact of the switch element with the associated counter-contact element and the switch element is retained on the counter-contact element by the magnetic force of the permanent magnet.
A particularly advantageous development of the invention resides in the fact that, with respect to a transverse plane of the switch device which intersects the magnet arrangements preferably centrally, two switch elements are disposed situated one opposite the other and are movable with their contact ends which are orientated towards each other transversely towards counter-contact elements which are disposed on both sides. This embodiment makes it possible to actuate both oppositely situated switch elements respectively with one magnet arrangement. As a result, a four-pole switch arrangement which is suitable in particular for a reference line can be achieved in a simple manner.
Within the scope of the invention, a switch element which can be moved in any way to one and the other side is basically suitable. Particularly advantageously, a switch element which is formed by a spring tongue is suitable, said switch element being able to be bent laterally in opposition to its elastic restoring forces based on intrinsic elasticity and returning in the inoperative state automatically into a central position from which it can be switched optionally to the one or other side.
In construction cases in which the switch device according to the invention is disposed in a protective housing, the electromagnet can be attached or incorporated in a lateral arrangement on the protective housing or by integration into the base region of the protective housing whilst ensuring a simple and compact construction.
Further development features of the invention lead to simple and compact constructions which can be produced economically and also enable reliable functioning and contacting.
Advantageous embodiments of the invention are subsequently explained in more detail with reference to several embodiments and drawings. There are shown:
The four switch devices of the two switch device pairs, which are designated in their entirety with 1, have respectively an electrical line 2 to a switch 3 and to a switch element 4 which is movable to and fro transversely relative to the electrical line 2 and serves to open or to close the line 2. The switch element 4 is an oblong element which is connected permanently at its base end 5 to the line 2 and, at its other end, has a contact end 6 with which it abuts, after a transverse movement, in its contact position on one of two counter-contact elements 7a, 7b which are disposed transversely at a spacing from each other. An open position can be produced in the illustrated central position in which the contact end 6 has a lateral spacing from the counter-contact elements 7a, 7b.
In the embodiment, the switch device 1 is part of a so-called reference line with switchable reference line portions 2a, 2b which are disposed in parallel and can be switched optionally by the switch element 4, at least one reference line portion being damped and forming a damped line. In
The switch element 4 is preferably laterally elastically flexible, its base end 5 being retained on a holder 9 which is mounted on a base 11. A spring tongue in the form of a flat strip is particularly suitable as flexible switch element, said spring tongue being illustrated in
In order to implement a switching procedure, in which the switch element 4 is moved laterally towards the one or the other counter-contact element 7a, 7b, a magnet arrangement 12a, 12b for lateral movement of the contact end 6 in the direction of and towards the one or the other counter-contact element 7a, 7b is provided on each side of the switch element 4.
In the embodiment according to
In the embodiment according to
The permanent magnets 13a, 13b can be disposed in a homopolar or non-homopolar manner. In the present embodiment, the permanent magnets 13a, 13b are orientated towards each other and towards the switch element 4 with their north poles N.
The permanent magnets 13a, 13b are thereby disposed on the sides of the reference line portions 2a, 2b which are orientated away from the switch element 4, a fixed connection being able to be present respectively therebetween, e.g. by gluing or soldering.
The magnetic force produced by the electromagnet 14a is superimposed on the magnetic force of the permanent magnet 13a as a function of the polarity. If the permanent magnet 13a and the electromagnet 14a have a homopolar configuration, the magnetic forces thereof are added so that the magnetic force of the permanent magnet 13a or of the magnet arrangement 12a is a low value when the electromagnet 14a is switched off. In the switched-on state, the magnetic forces are added to form a high value.
If the electromagnet 14a and the permanent magnet 13a are disposed in a non-homopolar manner, the magnetic forces are subtracted, in the switched-on state, to form a low value which can go as far as zero for example. In the switched-off state of the electromagnet 12a, the magnetic force of the permanent magnet 13a is a low value.
The magnetic forces are thereby designed such that the magnetic force of the permanent magnet 13b and the high value of the magnetic force of the magnet arrangement 12a are respectively able to draw the switch element 4 towards them and to bring and retain it in contact with the associated counter-contact element 7a, 7b. This applies to the high value of the magnetic force of the magnet arrangement 12a even when the effectiveness of the magnetic force of the permanent magnet 13 is available and to the magnetic force of the permanent magnet 13b and also when the effectiveness of the low value of the magnet arrangement 12a is available which can go as far as zero according to the design. Switching from the switching effectiveness of the magnet arrangement 12 to the switching effectiveness of the permanent magnet 13b or vice versa can be effected respectively by a current impulse which effects the pole switch of the electromagnet 12a.
If the poles N1, S1 of the electromagnet 14a are intended to be switchable, a pole switching mechanism 10 which is illustrated in a simplified manner is provided.
The embodiment on the right according to
In addition, the configuration and function of the embodiment according to
The embodiments according to
In the embodiments according to
It is furthermore advantageous to provide respectively one permanent magnet 12a or 12b with a magnetic force which is so great that the electromagnet 14a or 14b can be switched off directly after contact of the switch element 4 with the associated counter-contact element 7a or 7b and the switch element 4 is retained on the counter-contact element 7a or 7b by the magnetic force of the permanent magnet 13a or 13b.
The permanent magnets 13a and 13b which are situated opposite each other with respect to the line 2 can be respectively identical on the left and on the right in the embodiment according to
In all the embodiments, the switch element 4 is hence displaced magnetically into the respective contact position and retained in this position. Hence mechanically acting displacement elements which could produce abrasion material on the basis of pressure and frictional contact are dispensed with, which abrasion material could enter between the electrical contact surfaces and could damage the electrical contact.
In order to protect the electrical contact surfaces which cooperate with each other from contamination from outside, it is advantageous to dispose the switch device 1, at least with respect to the parts which have contact surfaces, in the protective space 21 of a preferably sealed housing 22.
The embodiments according to
In these constructions, the base 11 is formed by a housing base 22b and two oppositely situated lateral walls 22c, the cover 22a which can be placed thereon and two oppositely situated end walls 22d which are placed at the end side against the housing base 22b and the lateral walls 22c and are screwed thereon. Preferably, the end walls 22d project beyond the lateral walls 22c so that they receive also the cover 22a between themselves and can likewise be screwed thereon. In order to improve the seal of the internally flat adjacent end walls 22d, they are respectively sealed by a sealing ring 23 comprising elastically compressible material, such as rubber or plastic material, which preferably sits in an annular groove 24 in the abutment surface of the end walls 22d and projects slightly beyond the abutment surface.
In the central region of the end walls 22d, respectively one lead-through 25 for the electrical line 2 is disposed with respectively one bush-like cable screw connection 26 which protrudes outwards, and through which the electrical line 2 extends into the protective space 21 and is sealed, e.g. screwed in.
In the protective space 21 there are preferably located the holders 9 for the switch elements 4 in the end regions of said protective space. The holders 9 can be formed respectively by a clamping device with clamping jaws between which the associated switch element 4 can be clamped.
In addition, the embodiments according to FIGS. 3 to 6 have the following particular features. In the construction according to
The permanent magnets 13a, 13b are preferably disposed countersunk in upper-side transverse grooves 22e, the depth of the transverse grooves 22e being smaller than the height of the permanent magnets 13a, 13b so that the latter can project from the housing 22 at the top. In this case, transverse grooves 22f which fit in the underside of the cover 23 are disposed, into which transverse grooves the protruding portions of the permanent magnets 13a, 13b project. The length of the permanent magnets can thereby be adapted to the width of the housing 22 such that their laterally outer ends terminate substantially with the outsides of the housing 22, as is represented in
In the embodiment according to
In this embodiment, lateral and e.g. U-shaped core parts 16b are provided, which connect the cores of the permanent magnets 13a, 13b to the core of the electromagnet 14a which is designated with 16a or 16b in order to form an annularly closed common core up to the region of the switch device 1.
Within the scope of the invention, at least one of the permanent magnets 13a, 13b can be disposed not in the housing 22 but in the cover 22a.
Instead of a permanent magnet in the cover 22a, also a plurality of permanent magnets can be disposed therein, as
Within the scope of the invention, a plurality of switch devices 1 can be disposed in the protective space 21 of the housing 22 in the longitudinal direction of the line 2, situated one behind the other.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 052 591.9 | Oct 2004 | DE | national |
| 10 2005 025 403.9 | Jun 2005 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP05/11350 | 10/21/2005 | WO | 8/7/2007 |
