DE2304744B2 - Manually operated bistable electric magnetic switch - Google Patents

Description

5 °

The invention relates to a manually operable, bistable electrical magnetic switch with two one Permanent magnets located in a housing, designed as bridge magnets, between which there are A hermetically sealed, electrically and magnetically non-conductive capsule is located in the electrical Contacts are accommodated which are connected to electrical conductors carried out from the capsule, and with an armature or shunt that can be moved between the one permanent magnet and the capsule.

Such switches, also known as protective tube contacts, are used in particular in areas where there is a risk of explosion Environments required.

In a known switch of the type described above (see US-PS 30 09 033) there are two firmly clamped, resilient metal lamellae, which are brought into contact either by magnetic force depending on the position of the armature or bypass and thus close a circuit , or are not in contact with each other so that the circuit is broken. The disadvantage of such protective tube _{contacts with firmly clamped B} ei erne, in US-PS 2142 680 Beschnebenen floating apparatus for measuring liquid levels, a piston is attached to a floating body, which is moved depending on the liquid level in or out of the area of a permanent magnet to close or interrupt a magnetic circuit and thereby operate any switch, such as a mercury switch. This switch can be disregarded in further consideration due to its constituent differences.

The invention is based on the object of a «; to create a bistable electric magnetic switch that allows fast switching sequence, in which the switching movement -un not oppose any mechanical forces, so that there can be no heat generation and material openings that lead to failure or failure of the switch.

To solve this problem, the switch according to the invention is characterized in that the permanent magnets with their poles of the same name opposite each other by far, that inside the capsule there is a freely seductive Switching element made of electrically conductive, ferromagnetic material that electrically connects the contacts able to connect, is arranged. that in the room between the bridge magnet and the capsule the armature or shunt in the form of a circular arc section is rotatably mounted around the capsule, and that with the armature or shunt a knob or similar actuator is firmly connected.

Since the permanent magnets face each other with their poles of the same name, two separate magnetic field loops are created educated. The switch is operated by turning the anchor or shunt, whereby either one of the two magnetic field slides are closed over the armature, so that the corresponding permanent magnet then remains without any influence on the freely movable switching element. As a result of not being mechanical clamped, but freely movable switching element, a very fast switching sequence is possible, since the switching movement is not counteracted by mechanical forces.

Further features of the invention emerge from the subclaims.

An embodiment of the invention is in Drawing shown and is described in more detail below. It shows

F i g. 1 is a schematic sectional view of the inventive Switch and

2 shows a sectional view along the line H-II in

Fig. 1.

As shown in FIG. 1, the switch consists of a housing 7 in which two permanent magnets in the form of bridge magnets 1, Γ are housed. These magnets are spaced so that their poles of the same name are opposite each other. In the middle between the bridge magnets there is a hermetically

60

Table-closed contact capsule 2 made of a magnetism and electricity non-conductive material, in which a pair of electrical contacts 4 are attached near the lateral ends Housing 7 connected. In the hermetically sealed contact capsule 2 there is also a freely movable switching element 3 made of electrically conductive, ferromagnetic material, e.g. B. copper-plated soft iron that is able to electrically connect the contacts 4. In the free space between the bridge magnet 1 and the hermetically sealed contact capsule 2 is an arcuate armature 5 made of ferromagnetic material, for. As soft iron, provided for $ s hen which is mechanically fixedly connected to a mounted on the outside of the housing 7 turning knob 9, a rotatable leaf switch or a similar actuating device.

The permanent magnets are preferably made of a cobalt-rare earth alloy, for example a cobalt-samarium alloy. These alloys contain intermetallic compounds as their main constituent of type RC05, where R is a rare earth metal. These magnetic fabrics are about five times stronger than most alnico alloys and about twice stronger than platinum-cobalt magnets. they draw are characterized by a high energy product (BH) in the range of 16-20.10 * Gauss-Oerstedt (Ferrite 3, Alnico 5, Pt-Co 10.10 * Gauss-Oerstedt) and also show good high temperature resistance. Your curie point is higher than that of platinum-cobalt magnets. The use of cobalt samarium magnets makes it possible to keep the size of the magnets and thus that of the switch small.

The contact capsule 2 consists, as already mentioned, of a magnetism and electricity non-conductive material, expediently made of plastic or glass, and is z. B. in the area of the front ends with a Synthetic resin in the switch housing 7, which can also consist of pressed or injection-molded plastic, attached. If higher voltages are applied to the contacts 4 and stronger currents flow through them the interior of the contact capsule is expediently filled with a spark extinguishing agent, which is indicated by the reference number 6 and, for example, made of mineral oil, sulfur hexafluoride or the like. Can exist. It is then also recommended that the contacts be trough-shaped and the ends of the switching element 3 to be spherical. To accelerate the contact interruptions when switching off, the Contacts 4 can also be spring-loaded.

The armature 5 is expediently made of soft iron and is z. B. firmly connected to the rotary knob 9 by a welded arm (revenge shown). So that the armature 5 can only be rotated in rest positions in which it completely counteracts the switching element 3 shields one or the other of the two bridge magnets, the push button 9 or wing switch expediently equipped with a known spring-loaded latching device that ensures that at proper actuation of the switch is always carried out half an armature turn. On the The switching time itself has no influence on the speed of the armature rotation, as will be shown below.

From the F i g. 1 and 2 it is easy to see that in the illustrated position of the armature 5, the magnetic The flux of the lower bridge magnet 1 runs through the armature 5 and therefore that of ferromagnetic material existing switching element 3 not affected The switching element 3 is solely the force field of the upper bridge magnet 1 and is therefore attracted to this magnet, thereby connecting the circuit to the Contacts 4 is opened. If the armature 5 is now rotated by half a turn with the aid of the rotary knob 9, so the magnetic flux of the upper bridge magnet 1 is passed through the armature 5 and the switching element 3 shielded against the force field of the upper magnet. As a result, the switching element 3 comes into play of the force field emanating from the lower bridge magnet 1 is attracted by this magnet and bridges the contacts 4, whereby the circuit is closed. The speed with which the armature 5 is rotated has no effect on the switching time when making or breaking contact Influence. Even if the armature 5 is rotated only slowly, the contact is made or the contact is interrupted in a fraction of a second, as soon as the field of one magnet is sufficiently weakened and that of the other magnets is reinforced accordingly in order to cause any movement of the switching member 3. Due to the high switching speed, the formation of breakaway arcs at high currents is largely avoided or reduced and so an undesirable heating of the switch with frequent switching prevented.

From the above description it can be seen that the switch also with prolonged use and high Switching frequency remains absolutely explosion-proof, as there are no parts that could be used when operated frequently leak and then allow an ignitable gas / air mixture access to the contacts.

1 sheet of drawings

Claims (5)

Patent claims: 1. Manually operated, bistable electric magnetic switch with two permanent magnets located in a housing, designed as bridge magnets, between which there is a hermetically sealed, electrically and magnetically non-conductive capsule, in which electrical contacts are housed that lead out of the capsule electrical conductors are connected, and with a movable armature or shunt between the one permanent magnet and the capsule, characterized in that the permanent magnets (1, V) are located at a distance with their poles of the same name that a free one inside the capsule (2) Movable switching element (3) made of electrically conductive, ferromagnetic material, which is able to electrically connect the contacts (4), is arranged that in the space between the bridge magnet (1, V) and the capsule (2) the armature or Shunt (5) is rotatably mounted in the form of a circular arc section around the capsule (2), and that with the armature bz w. shunt (5) a rotary knob (9) or a similar actuator is firmly connected. 2. Electrical bistable magnetic switch according to claim 1, characterized in that the contact capsule (2) is filled with a spark extinguishing agent (6) such as mineral oil, sulfur hexafluoride or the like. 3. Electrical bistable magnetic switch according to claim 1 or 2, characterized in that the Contacts (4) are cushioned. 4. Electrical bistable magnetic switch according to one of claims 1 to 3, characterized in that that the ends of the switching element (3) are spherical and the contacts (4) are trough-shaped are. 5. Electrical bistable magnetic switch according to one of claims 1 to 4, characterized. that the switching element (3) consists of copper-plated soft iron. resilient metal lamellae consists in the fact that these Meailamellen on the basis of their material properties or spring constant, oppose the switching movement with a force, whereby, with increased switching sequence, heat is developed at the bending points, which leads to a honing Material mouth with changed switching characteristics and can lead to a breakdown or failure of the switch. Further comparable protective tube contacts can be found in FRPS ₁₄₂ 4 936 and DT-Gbm 18 05 188