EP0573471B1 - Electromechanical connecting device - Google Patents

Abstract

An electromechanical connecting device (1) comprises a switch device (2), which has a magnetic switch (4) and can be connected to a voltage source, and at least one trigger device (3), which has a trigger magnet (14 or 15) and can be connected to a consumer. The electromechanical connecting device (1) can bring the magnetic switch (4) from a rest position into a working position, thereby establishing the contact between at least one pair of contacts and the electrical connection between the switch device (2) and the trigger device (3). To produce a precisely defined switching point, the magnetic switch (4) has two magnets (5 and 6) which slide in the switch device (2) and close the contact between two pairs of contacts. The two magnets (5 and 6) are arranged on a magnet carriage (7) which, in the rest position, is urged by magnetic forces against a limit stop (9).

Description

The invention relates to an electromechanical connecting device with a switching device that can be connected to a voltage source and has a bistable magnetic switch and a triggering device that has at least one release magnet and that can be electrically connected to a consumer, by means of which the magnetic switch can be brought from a rest position against a restraining force into a working position and thereby the contact at least one contact pair and the electrical connection between the switching device and the triggering device can be established.

Connecting devices in which the switching device is designed as a bistable magnetic switch are known. For example, a magnetically operated electrical switch is described in DE 29 09 448, which has a switching device, the magnetic switch of which is actuated via a pivotably fixed magnet. In the open position, the switching magnet which actuates the magnetic switch is pivoted out of the area of the contact pair by two further magnets which have an oppositely polarized field to such an extent that the switch is open. This closes the switch achieved that the pivoted-out magnet is approximated in a release device provided trigger magnet which attracts the magnet and where it is pivoted far towards the contact pair until the magnet abuts the contact pair and closes it. The electrical connection from the voltage source to the consumer is finally established by placing the triggering device on the switching device. It has been found to be disadvantageous in this known arrangement that, due to the pivotable fixing of the magnet actuating the magnet switch in the switching device, a not inconsiderable overall depth and width is required, since the magnet has to pivot back a certain distance. In addition, it has been found to be disadvantageous that the switching point at which the contact pair is closed can only be set inaccurately, since this is dependent on the magnetic force of the magnet to be pivoted, on the magnetic force of the magnets deflecting, laterally arranged, and finally on the magnetic force of the Trigger magnet depends. This results in difficult to reproduce power relationships, which requires a generous geometric design of all elements. In particular, to avoid accidental switch-on in the event of vibrations. Due to the inaccurately adjustable switching point, there is the possibility that the contact pair is brought into mutual contact by the magnet and the contact surface lying on the surface of the switching device is connected to the voltage source before this contact surface the approximate triggering device has been completely covered. Even when the trigger device is lifted off, there is a risk, in particular due to the hysteresis, that one can accidentally come into contact with the contact surface and receive an electric shock if the device is operated carelessly. This is avoided in the known device in that the contact surface of the switching device is surrounded by a large-sized edge into which the triggering device must be inserted. Child safety is only guaranteed to a limited extent. The principle of the protective contact plug common in the Federal Republic of Germany is therefore used. Although this prevents the contact surface and thus a live pole from being touched, it must be accepted that the depth of the device is increased even further by this measure and that the device is difficult to clean due to the protruding edge. In addition, with a protruding edge, the risk of damage to the edge is increased, which can lead to a safety impairment. Furthermore, the aesthetics of this device are only moderately attractive.

With the US-A-3,816,679 a connector has become known which is switchable via a trigger device having a magnet. It has been found to be disadvantageous that the interior of the switching device of the connector is not secure against unauthorized access and that the switching device is equipped with commercially available magnets is switchable. Such connectors are a source of danger.

On the basis of this prior art, the object of the invention is to provide an electromechanical connecting device of the type mentioned at the outset with a lower overall depth, which corresponds to high safety requirements.

This object is achieved in that the switching device is designed as a closed unit that the contacts of two pairs of contacts are closed or opened in the magnetic switch by at least one switching magnet guided displaceably in the switching device, each switching magnet of the switching device by specially coded in the release device realized magnetic fields can be switched into the working position and in particular the switching device is pushed against a stop with a certain threshold force in the rest position.

Specially encoded magnetic fields are understood to mean magnetic fields that are not available in normal, everyday surroundings, in particular cannot be generated by common household magnets, which increases the child safety of the connecting device. These special magnetic fields can be realized, for example, by using particularly strong high-energy magnets, or they are realized by magnetic coding. The closed structural unit of the switching device ensures a further increase in safety. This prevents unauthorized intervention and touching of the contacts. Finally, the swelling force which pushes the switching device against a stop in the rest position prevents switching of the device with conventional magnets.

Characterized in that the magnetic switch has at least one magnet slidably guided in the switching device, which is pushed against a stop in the rest position, the contact of the two contact pairs is only closed when the magnet leaves the rest position and assumes the working position, whereby it is linear Movement. In addition, the linear movement of the magnet is much easier to control than swivel movements or the like. In the case of linear movement, the contact between the two contact pairs is advantageously only closed when the magnet has completely passed through the displacement path and accordingly assumes its working position. The at least one magnet is advantageously arranged on a magnetic carriage. The rest position of the magnetic carriage is defined in that it is pushed against a stop by magnetic forces. If the one or two release magnets of the release device are moved in the direction of the switching device, then the magnetic forces of the release magnets act on the magnetic slide. Because the magnetic carriage due to the interaction of the magnetic forces the magnet of the switching device is pressed against a stop with a ferromagnetic plate or a permanent magnet, the latter does not leave its rest position as long as the magnetic forces of the release magnet do not outweigh the magnetic forces of the magnets of the switching device. From a certain position of the release magnet in relation to the switching device, however, its magnetic forces become so great that they cancel out the magnetic forces of the magnets of the switching device: the magnetic carriage changes its position in the direction of the working position and closes the contacts of the two contact pairs. In contrast to the prior art, where the magnet gradually moves towards the contact pair as the triggering device approaches, the contact pair is closed spontaneously in the invention. This not only results in a precisely definable switching point, but also a spark-proof switching is guaranteed. The tripping magnets therefore have a tripping and a holding function.

In addition, the arrangement of the magnet or the magnets of the switching device on a magnetic slide has the advantage that both contacts are either switched on or off at the same time, that there is a faster switch-off behavior, in particular when the trigger element is lifted at an angle, and that a switching process only is triggered when the release magnets interact with the magnetic slide in the geometrically intended position. The simultaneous switching of both contact pairs also increases the safety of the Connecting device, whereby the possibility is excluded that, for example, when the triggering element is turned off, no contact, for example via the consumer, is under voltage and can possibly be touched.

Since the magnetic force of the magnets of the switching device and the magnets of the triggering device are also reversibly temperature-dependent, a further safety aspect is created with the connecting device according to the invention in that the contacting is interrupted from a certain temperature. If, for example, there is a liquid film on the contact surface and this represents a resistance, its temperature is gradually increased by the current flowing through it. However, the housing of the switching device and the housing of the triggering device are also heated, which is harmless below a certain temperature limit. Above a certain temperature, however, this can damage the device. The magnets can now be selected so that their attraction is no longer sufficient for mutual attraction from a certain temperature that is below the critical temperature. If the device according to the invention heats up until this temperature is reached, the magnetic switch drops and returns to its rest position. Since there is no longer any current flowing, there is no further heating and the entire device gradually cools down again. If it has reached a temperature at which the magnets have regained their original attraction, the connection between the two devices is restored. Total failure due to thermal damage is therefore excluded by the connecting device according to the invention.

In a further development it is provided that the switching device has a conventional plug and / or the triggering device of a conventional socket. Due to this configuration, a child safety device is created in that the switching device can be plugged into a conventional socket and thus this socket can be converted for the system of the connecting device according to the invention. The plug of the consumer can also be converted in that the release device has a conventional socket, so that it can be connected to the conventional plug. The devices designed in this way can be handled like adapters. In order to avoid unintentional detachment from the conventional plugs or sockets, they have screw or snap devices with which only a controlled removal is possible.

Figur 1

einen Längsschnit durch eine erste Ausführungsform der erfindungsgemäßen Vorrichtung mit von der Schalteinrichtung abgehobener Auslöseeinrichtung und in der Ruhelage sich befindendem Magnetschalter;

Figur 2

ein Kraft-Wege-Diagramm, die Schaltcharakteristik einer Ausführungsform der erfindungsgemäßen Vorrichtung zeigend;

Figur 3

ein weiteres Kraft- Wege-Diagramm, die Schaltcharakteristik der in Figur 1 dargestellten Ausführungsform der Vorrichtung zeigend;

Figur 4

einen Schnitt IV-IV gemäß Figur 1;

Figur 5

eine Draufsicht auf eine Ausführungsform des Magnetschlittens;

Figur 6

eine Draufsicht auf die Kontaktseite einer weiteren Ausführungsform der Auslöseeinrichtung.

Further advantages, features and details of the invention emerge from the following description, in which particularly preferred exemplary embodiments are described in detail with reference to the drawing. Here The features mentioned in the description and reproduced in the drawing can each be implemented individually or in any combination in the invention. The drawing shows:

Figure 1

a longitudinal section through a first embodiment of the device according to the invention with the triggering device lifted off the switching device and the magnetic switch located in the rest position;

Figure 2

a force-path diagram showing the switching characteristic of an embodiment of the device according to the invention;

Figure 3

another force-displacement diagram, showing the switching characteristic of the embodiment of the device shown in Figure 1;

Figure 4

a section IV-IV of Figure 1;

Figure 5

a plan view of an embodiment of the magnetic carriage;

Figure 6

a plan view of the contact side of a further embodiment of the triggering device.

FIG. 1 shows a longitudinal section through a first embodiment of a connecting device, generally designated 1, which has a switching device, designated 2, and a triggering device, designated 3. A magnetic switch 4 is arranged in the switching device 2 and consists of two magnets 5 and 6 and a magnetic slide 7 connecting the magnets 5 and 6. The magnetic carriage 7 is essentially plate-shaped and carries the two magents 5 and 6 on one flat side, high-energy magnets from the rare earth group, such as samarium-cobalt or neodymium-iron-boron, preferably being used. On the opposite flat side, the magnetic carriage 7 bears against a ferromagnetic plate 8 fixed to the housing, which serves as a stop 9. The position of the magnetic switch 4 shown in FIG. 1 or the position of the magnetic carriage 7 with the magnets 5 and 6 represents the rest position. This rest position is stable since the magnetic carriage 7 is attracted to the ferromagnetic plate 8 by the attraction force of the magnets 5 and 6 is pushed to this. This attractive force depends on the magnetic force of the magnets 5 and 6 and on the distance of these magnets from the ferromagnetic plate 8. This distance is determined by the thickness 10 of the magnetic carriage 7 and possibly by a galvanizing layer 11 or another electrically conductive connection between the ferromagnetic plate 8 and the magnets 5 and 6 is applied on one flat side of the magnetic carriage 7. Furthermore, in FIG. 1 recognizable that spring elements 12, shown schematically, rest against the magnetic carriage 7 without pretensioning.

The tripping device 3 consists essentially of a housing 13 and two tripping magnets 14 and 15 fixed in the housing 13, of which in this embodiment one pole is flush with the flat side facing the switching device 2.

If this triggering device 3 is brought closer to the switching device 2, the two triggering magnets 14 and 15 exert magnetic forces on the magnets 5 and 6. If the attraction force of the two release magnets 14 and 15 is so great that it outweighs the holding force of the magnets 5 and 6 with respect to the ferromagnetic plate 8, the magnetic slide 7 is linearly displaced in the direction of the release element 3, ie vertically upwards in FIG . The end of the displacement path 22 is reached when the magnets 5 and 6 rest on the inside of contact caps 17 and 18 let into the housing 16 of the switching device 2. In this position, the electroplating layers 11 of the magnetic carriage 7 also rest on contact points 19 and 20, which in turn are connected to a voltage source, not shown. The magnetic carriage 7 is now in the working position and connects the contact points 19 and 20 to the contact caps 17 and 18. These contact caps 17 and 18 are located on the Triggers 14 and 15, which in turn are connected to a consumer, also not shown.

A good electrical contact between the contact points 19 and 20 and the consumer is ensured in that the magnets 5 and 6 or 14 and 15 have a low electrical resistance, the electrical conductivity possibly being further reduced by galvanizing with copper. The magnets 5 and 6 are soldered onto the magnetic carriage 7, the electrical connection between the magnets 5 and 6 being interrupted by at least the surge-proof air gap 21. The thin, low-resistance and non-ferromagnetic contact caps 17 and 18 are located at a distance 22 from the magnets 5 and 6, the distance 22 corresponding to the working path of the magnetic carriage 7 from the rest position into the working position. This distance 22 also corresponds to the distance 23 of the contact points 19 and 20 from the electroplating layer 11 of the magnetic carriage 7. The sum of the two distances 22 and 23 correspond at least to the surge-proof air gap 21. Finally, the housing has an earthing ring 56 in the region of its edge.

The diagram reproduced in FIG. 2, which can only be understood qualitatively, shows the switching characteristics of the embodiment of FIG. 1, the spring elements 12 being disregarded, ie the spring elements 12 have a spring force of zero. Along the abscissa is the Distance s between the magnets 5 and 6 and the release magnets 14 and 15 is plotted in mm, whereas the ordinate indicates the force F acting on the magnetic slide 7. The switch-on and switch-off points 24 and 25 are reached when the magnets 5 and 6 are in contact with the contact caps 17 and 18 or are detaching from them. When the triggering device 3 approaches, the force curve follows the curve 26. From the line of intersection with the abscissa, the magnetic carriage 7 begins to move freely over the working path 22 (dashed line) until the magnets 5 and 6 on the inner surfaces of the contact caps 17 and 18 concerns. When the triggering device 3 is lifted, the force curve follows the curve 27 until the magnetic slide 7 is pulled back into the rest position at the switch-off point 25. From the switch-off point 25, the magnetic carriage 7 moves along the dashed line there to the curve 26. The switching characteristic shows a pronounced hysteresis behavior. The triggering device 3 must be lifted a few mm (in the drawing approx. 9 mm) before switching off. In order to avoid a geometrical safety precaution in the form of a depression, the restoring force is supplemented by the spring elements 12 with a linear characteristic. This allows the hysteresis to be narrowed to approx. 0.1 to 0.5 mm. Such a switching characteristic is shown in the force-displacement diagram of FIG. 3, which is also only to be understood qualitatively. The switch-on and switch-off points 24 and 25 can be set close above the surface of the switching device 2.

As already mentioned, the spring element 12 shown in FIG. 1 is only shown schematically. An embodiment of this spring element 12 is shown in FIG. 4, which shows a section IV-IV of FIG. 1. In this embodiment, the spring element 12 is designed as a leaf spring 28, which is clamped on both sides in the housing 16 and extends centrally over the entire contact surface of the electroplating layer 11 of the magnetic carriage 7 and is fastened to the latter. The magnetic carriage 7 is therefore no longer freely movable, but is guided in a defined manner by the leaf spring 28. This avoids frictional forces and losses. In order to ensure safe, resilient contacts, the contact point 20 is also designed as a leaf spring and has a small spring travel 29. The leaf spring 28 is not biased in the rest position.

FIG. 5 shows a top view of an embodiment of the magnetic carriage 7, which essentially has the shape of a rectangle, in which contact tongues 30 project on both sides in the longitudinal axis. These contact tongues 30 are used to fasten the leaf springs 28. A magnetic slide 7 designed in this way, which carries the magnets 5 and 6, has the advantages over independently switchable individual magnets that both contacts are either switched on or off at the same time, so that they are switched on Faster switch-off behavior, in particular when the trigger device 3 is lifted at an angle have, and that a switching operation is only triggered when both triggering magnets 14 and 15 interact in the geometrically intended position with the magnetic carriage 7. The force of a single magnet is not sufficient to move the magnetic carriage 7 from the rest position into the working position or to hold it there.

In order to prevent the magnetic carriage 7 from being switched with any sufficiently strong magnets, in particular potential household magnets, the magnets 5 and 6 or 14 and 15 used are coded in a preferred embodiment. This is done e.g. in that the magnets 5 and 6 or 14 and 15 are composed of a plurality of alternately polarized magnets. The most useful is the coding shown in FIGS. 5 and 6, in which a cylindrical inner magnet 31 is inserted with opposite polarity into a ring magnet 32 of approximately the same volume. Other encodings are conceivable as long as they meet the requirement of rotational symmetry around point 33.

Another advantage of alternately polarized fields is the increased adhesive force, which is significantly improved especially against lateral displacement. With the proposed coding, this improvement in adhesive force is easily achieved in all directions of the surface plane. Another advantage of magnetic fields with opposite polarity is finally a faster switch-off behavior of the bistable magnetic switch 4, in particular when turning off.

FIG. 6 shows a top view of the contact surface of the release device 3, in which the release magnets 14 and 15 are firmly connected to the non-magnetic and insulating housing 13. The connection cables, not shown, are e.g. soldered directly to the trigger magnets 14 and 15. It can also be seen in FIG. 6 that the two magnets 14 and 15 are surrounded by an earthing ring 34 which is flush with the electrically insulating housing 13 and has at least one surge-proof air gap 35 from the magnets 14 and 15. If, in the case of a triggering device 3 designed in this way, a flat metal object is pushed between the triggering device 3 and the switching device 2 and a live pole is touched, the risk of an electric shock is avoided by the grounding ring 34.

Claims (15)

1. Electromechanical connecting device (1) comprising a switch device (2) which can be connected to a voltage source and which is provided with a magnetic switch (4), and a trigger device (3) which is provided with at least one trigger magnet (14,15) and is electrically connectable to a consumer, with which the magnetic switch (4) can be brought, against a restraining force, from a rest position to a working position, thereby establishing contact between at least one pair of contacts and electrical connection between the switch device (2) and the trigger device (3), characterized in that the switch device (2) is formed as an enclosed unit, and in that in the magnetic switch (4) the contacts of at least two pairs of contacts are closed or opened by switching magnets (5,6) displaceably guided in the switch device (2), each of the switching magnets (5,6) of the switch device (2) being switchable into the working position by means of specially coded magnetic fields generated in the trigger device (3) and in particular the switch device (2) in the rest position being urged with a predetermined threshold force against a limit stop (9).
2. Connecting device as claimed in Claim 1, characterised in that the switching magnets (5,6) and the trigger magnets (14,15) of the switch device are formed as high energy magnets, and in particular comprise members of the rare earth group, such as samarium-cobalt or neodymium-iron-boron.
3. Connecting device as claimed in one of the preceding claims, characterised in that the switching magnet (5,6) of the switch device (2) and the trigger magnets (14,15) of the trigger device (3) have corresponding magnetic coding, in particular fulfilling the requirement of rotational symmetry, and in particular are formed as ring magnets inserted into each other.
4. Connecting device as claimed in one of the preceding claims, characterised in that the contacts of the pair of contacts are closed and opened by means of at least one switching magnet (5,6), which is in particular arranged on a magnet carriage (7), where there are several such switching magnets the switching magnets (5,6) being moved simultaneously.
5. Connecting device as claimed in claim 4, characterised in that the magnet carriage (7) is urged into the rest position by the switching magnets (5,6) acting on a ferromagnetic plate (8) or permanent magnet.
6. Connecting device as claimed in one of claims 4 or 5, characterised in that the displacement direction of the switching magnets (5,6) from their rest position into the working position corresponds to the direction of approach of the trigger device (3) onto the switch device (2).
7. Connecting device as claimed in one of claims 4 to 6, characterised in that the switching magnets (5,6) and or the magnet carriage (7) are urged into the rest position by additional mechanical elements, such as springs (12,28) or the like.
8. Connecting device as claimed in one of claims 4 to 7, characterised in that the magnet carriage (7) is permanently connected with the voltage source or in the working position bridges the contacts of the pair of contacts.
9. Connecting device as claimed in one of the preceding claims, characterised in that the switching magnets (5,6) and/or the trigger magnets (14,15) are formed as current carrying elements and in particular are connected via a connecting cable with a voltage source or a consumer.
10. Connecting device as claimed in one of the preceding claims, characterised in that the switch device (2) has a flat upper surface and the contacts accessible from the exterior comprise a low resistance, non-ferromagnetic material.
11. Connecting device as claimed in one of the preceding claims, characterised in that the switch device (2) and the trigger device (3) are each provided with an earthing ring (34) which surrounds one of the contacts.
12. Connecting device as claimed in one of the preceding claims, characterised in that the trigger magnets (14,15) are connected to a current conductor (50).
13. Connecting device as claimed in one of the preceding claims, characterised in that it has a unitary construction including not only the switch device (2) but also the trigger device (3).
14. Connecting device as claimed in one of the preceding claims, characterised in that it is formed as an adaptor and the switch device (2) is provided with a conventional plug and/or the trigger unit (3) with a conventional socket.
15. Connecting device as claimed in one of the preceding claims, characterised in that the base of the housing (16) is provided with contact plates in the form of contact springs which are each connected with one pole of the voltage source.

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