EP2208261B1 - Device for the sparkless disconnection of a solenoid - Google Patents

Description

The invention relates to a device for spark-free unplugging a via two electrical connector elements of a connector assembly with two DC voltage contacts electrically connectable solenoid.

In the separation of live magnetic coils, such as valve solenoid coils of their electrical connections due to the induction voltage generated sparks, which may not occur in explosion-proof environment. This problem also occurs, for example, in explosion protection in categories 2 and 3. In order to avoid such sparks, it is known to connect a protective diode in parallel with the magnetic coil. About this diode when unplugging the polarity of the terminals oppositely directed induction voltage is reduced or short-circuited, so that no energy for sparking remains. The disadvantage of this known arrangement is that the Schuztdiode is firmly connected to the solenoid or integrated in the magnetic coil containing device, for example in a solenoid valve. Since you usually do not know in particular in mass production, in which environment the device should work later, considerable costs and considerable effort would be necessary to prophylactically integrate a protective diode in all devices. Since only very few devices will be used later in an explosion-proof environment, such would be one Expenditure also not to represent. On the other hand, it also means no small effort to produce small series of devices especially for explosion-proof environments. Another problem is that when replacing a device in an explosion-proof environment it is sometimes impossible to determine with certainty whether the new device also contains a protection diode.

With regard to this prior art is on US Pat. No. 7,063,570 B1 which shows the features of the preamble of claim 1.

In addition, with magnetic coils provided with a protective diode, it must be ensured that the terminal polarity is correct, otherwise the protective diode would be destroyed.

An object of the present invention is to provide a device of the type mentioned, by the use of non-provided with protective diodes magnetic coils or devices provided with magnetic coils is also possible in explosion-proof environment and it is ensured that when unplugging nevertheless no sparking.

This object is achieved by a device having the features of claim 1.

Advantageously, the protective diode is not arranged on the magnetic coil or on the device provided with the magnetic coil but in the plug-in receptacle for the connector elements of the magnetic coil. It is ensured that the separation of the connection of one of the connector elements with the associated DC voltage contact, the protective diode still connects the two connector elements of the magnetic coil, so that the negative voltage pulse is short-circuited by induction, without a sparking can occur. The diode also acts as an overvoltage limit during the regular shutdown process. It can thus magnetic coils be plugged with and without protection diode, so that appropriate considerations, which solenoid can be used, are not required. It can be used simple and inexpensive magnetic coils or devices provided with magnetic coils without protective circuit, so standard magnetic coils, especially in environments where explosion protection is required or mandatory.

The measures listed in the dependent claims advantageous refinements and improvements of claim 1 device are possible.

In an advantageous first embodiment, the second portion of the first spring assembly is electrically fixed to the first DC voltage contact and lies in the Aussteckrichtung behind the second portion elastically on the first connector element. The two subregions of the first spring arrangement are expediently designed as spring tongues, which also applies in particular to the second spring arrangement. Here, simple and inexpensive spring arrangements can be used.

In an advantageous second embodiment variant, the first spring arrangement is formed as a two-stage, compressible by the first connector element when inserting pressure spring assembly, wherein the first portion rests as a first stage on the first connector element and the second portion as a second stage for electrical connection to the first portion and the first DC voltage contact is formed from a predetermined spring pressure. By optimizing the spring characteristics, it is possible to determine how long the diode has time for the short-circuiting of the negative voltage pulse, for which only a few μsec is needed.

The first portion is suitably designed as a helical spring and the second portion as a leaf or plate spring. In principle, it is also possible to form both partial areas as a helical spring or both partial areas as leaf or plate springs.

The second spring arrangement is expediently designed in the second embodiment as compressible by the second connector element when inserting compression spring assembly and has spring properties that ensure release of the system on the second connector element when unplugging the electrical connection of the first spring assembly from the first DC voltage contact.

The two plug-in connection elements are expediently arranged on the housing of a magnetic valve in which the magnetic coil is located. In principle, a cable connection is possible.

A plug-in receptacle of the plug connection arrangement for receiving the plug connection elements can be arranged on a housing or on an electrical, connectable with a cable coupling element.

Figur 1

ein mit einer Magnetspule versehenes Gerät, dessen Steckverbindungselemente in eine Steckaufnahme einer Steckverbindungsanordnung eingesteckt sind als erstes Ausführungsbeispiel der Erfindung,

Figur 2

dieselbe Anordnung während des Aussteckvorgangs bei dem die Verbindung zum negativen Pol einer Versorgungsspannungsquelle bereits unterbrochen ist,

Figur 3

dieselbe Anordnung im ausgesteckten Zustand und

Figur 4

eine ähnliche Anordnung im eingesteckten Zustand als zweites Ausführungsbeispiel der Erfindung.

Two embodiments of the invention are illustrated in the drawing and explained in more detail in the following description. Show it:

FIG. 1

a device provided with a magnet coil whose plug connection elements are plugged into a plug receptacle of a plug connection arrangement as a first exemplary embodiment of the invention,

FIG. 2

the same arrangement during the Aussteckvorgangs in which the connection to the negative pole of a supply voltage source is already interrupted,

FIG. 3

the same arrangement in the unplugged state and

FIG. 4

a similar arrangement in the inserted state as a second embodiment of the invention.

In the in the FIGS. 1 to 3 illustrated first embodiment, a schematically illustrated solenoid valve 10 includes a magnetic coil 11, the electrical connections with two connector elements 12, 13 of a connector assembly 14 are connected. The two plug connection elements 12, 13 can be arranged either on the housing of the solenoid valve 10 or on a plug which is connected via lines to the solenoid valve 10. Instead of a solenoid valve 10, the solenoid coil 11 may also be arranged or integrated in another electrical device, for example in an electromagnet, a relay or the like.

The plug-in connection elements 12, 13 together with an electrical plug-in receptacle 15, the plug connection arrangement 14. The plug receptacle 15 may be arranged on or in an electrical device or formed as an electrical counter-coupling element or mating connector, which is mounted on an electrical cable 16. In the case of the arrangement on or in an electrical device, the electrical cable 16 extends within the same and is connected in each case to an unillustrated electrical DC power source.

Opposite the two insertion openings 17, 18 for receiving the two plug connection elements 12, 13, two DC voltage contacts 19, 20 are arranged in the plug receptacle 15, wherein the DC voltage contact 19 is connected to the negative pole and the DC voltage contact 20 to the positive pole of the DC voltage source. About the negative DC voltage contact 19, a two-stage compression spring assembly 21 is arranged, the first portion 22 is formed as a first step as a helical spring and the first insertion 17 faces, while the second portion 23 is formed as a second stage as a leaf or plate spring and the negative DC voltage contact 19th bridged.

At the positive DC voltage contact 20, a second, designed as a helical spring compression spring arrangement 24 is arranged, which faces the second insertion opening 18.

The first two-stage compression spring assembly 21 and its second portion 23 is connected via a protective diode serving as a diode 25 to the positive DC voltage contact 20 and poled so that it locks when applying the DC voltage. Instead of a diode 25, a plurality of diodes may also be connected in parallel and / or series connection.

In FIG. 1 a state is shown in which the plug connection elements 12, 13 are inserted into the plug receptacle 15. In this case, the first compression spring assembly 21 is compressed by the first connector element 12, that the second portion 23 comes into contact with the negative DC voltage contact 19, which mechanically bridged in the unloaded state, that is not electrically connected to the second portion 23 of the first compression spring assembly 21. The installation of the two plug-in connection elements 12, 13 on the two compression spring arrangements 21, 24 thus leads to that the magnetic coil 11 is acted upon by the DC voltage.

In FIG. 2 is a state shown in which the connector elements 12, 13 are already partially pulled out, that occupy a position during the Aussteckvorgangs. In this state, the two compression spring assemblies 21, 24 are still at the two connector elements 12, 13, but the spring force has already been reduced so that the second portion 23 of the first compression spring assembly 21 has lifted from the first DC voltage contact 19 and no longer connected to this consists. However, the diode 25 continues to connect the two connector elements 12, 13 via the two compression spring assemblies 21, 24. By the separation from the circuit an oppositely directed induction voltage in the solenoid 11 is formed, which can now be degraded via the diode 25, so that no Abschaltfunken arise and so an operation in explosion-proof environment is possible.

In FIG. 3 is the fully unplugged state shown in which the two connector elements 12, 13 have no contact with the compression spring assemblies 21, 24 more.

The spring force, in particular of the first compression spring arrangement 21, must be adjusted such that the first partial region 23 of the first compression spring arrangement 21 designed as a leaf or plate spring is pressed down in such a way that it comes into contact with the negative direct voltage contact 19. If the first subregion 22 of the compression spring arrangement 21 has a harder spring characteristic than the second subregion 23, a relatively early contact takes place when the plug connection elements 12, 13 are plugged in, and a relatively late detachment occurs during disengagement From the first DC voltage contact 19, while this is the case in reverse properties in the reverse manner, ie at a first portion 22 with softer spring characteristic over the second portion 23 is a relatively late contact during insertion and a relatively early contact separation during unplugging.

In a modification of the illustrated embodiment may be used instead of a combined two-stage compression spring assembly 21, one in which the two portions are formed by two coil springs or by two leaf or disc springs in a stepped arrangement, ie in a row. The second compression spring assembly 24 is then each formed with appropriate dimensioning and spring characteristics, that is, in the illustrated embodiment, the second compression spring assembly 24 has the same or similar spring characteristics as the first portion 22 of the first compression spring assembly 21.

Of course, the first compression spring arrangement 21 and the second compression spring arrangement 24 can also be arranged reversed with respect to the two poles, wherein two-stage compression spring arrangements can in principle also be provided at both poles. The essential thing is merely that when unplugging the connector elements 12, 13 is still a contact with the two terminals of the diode 25 after the connection with one of the DC voltage contacts 19, 20 has been disconnected.

At the in FIG. 4 illustrated second embodiment are the same or equivalent components or assemblies provided with the same reference numerals and not described again. Instead of pressure or coil springs occur in the second embodiment, spring tongues 26 to 28, which in inserted state of the two connector elements 12, 13 abut resiliently laterally thereto and thereby establish the electrical connection with the two DC voltage contacts 19, 20 and the diode 25.

The two spring tongues 26, 27 form a first spring assembly 29, wherein the spring tongue 26 is connected as a first portion of the first spring assembly 29 with a terminal of the diode 25 and the spring tongue 27 as the second portion of the first spring assembly 29 with the negative DC voltage contact 19. These two spring tongues 26, 27 are in the insertion direction one behind the other laterally on the first connector element 12, wherein the system of the spring tongue 26 is further removed from the negative DC voltage contact 19, as the system of the second spring tongue 27th

The spring tongue 28 forms the second spring arrangement 30, which rests in the inserted state of the connector elements 12, 13 on the second connector element 13 in height corresponding to the spring tongue 26.

As a result of this step-like arrangement of the spring tongues 26, 27 on the first connector 12 loses when unplugged first connected to the negative DC contact 19 spring tongue 27 makes contact with the connector element 12, so that the circuit is separated to the solenoid 11. About the then still in contact with the two connector elements 12, 13 located spring tongues 26 and 28 which are connected to the diode 25, this diode 25 bridges the two terminals of the solenoid 11 and closes the induction voltage spark-free short. Only then is a release of the remaining spring tongues 26, 28 of the connector elements 12, 13th

For the distance of the system of the spring tongue 28 on the second connector element 13, it is essential that this system still exists when the spring tongue 27 detaches from the connector element 12.

When in FIG. 4 shown second embodiment, instead of the connector assembly 14 of the first embodiment, a modified connector assembly 14 'and instead of the socket 15 of the first embodiment, a modified socket 15'.

Claims (12)

1. Device for the spark-free unplugging of a magnet coil (11) which may be connected via two electrical plug-in connection elements (12, 13) of a plug-in connection assembly (14; 14') to two DC voltage contacts (19, 20), characterised in that the first and the second of these plug-in connection elements (12, 13) is electrically connected in the plugged-in state, via a first and a second spring assembly (21, 24; 29, 30) to the first and second DC voltage contact (19, 20) and at least one diode (25) polarised in the inhibiting direction connects the two spring assemblies(21, 24; 29, 30) to one another, and that at least the first spring assembly (21; 29) consists of two sections (22, 23; 26, 27), of which the first section (22; 26) is connected constantly to the diode (25) and flexibly contacts the first plug-in connection element (12) in the plugged-in state, and of which the second section (23; 27) of this plug-in connection element (12) in the plugged-in state makes electrical contact with the first DC voltage contact (19), wherein the second section (23; 27) is designed, during unplugging, to break this electrical connection before the release of the contact of the first section (22; 26) of this spring assembly (21; 29) at the first plug-in connection element (12) and before the release of the contact of the second spring assembly (24; 30) at the second plug-in connection element (13).
2. Device according to claim 1, characterised in that the second section (27) of the first spring assembly (29) is electrically connected securely to the first DC voltage contact (19) and in the direction of unplugging makes flexible contact with the first plug-in connection element (12) behind the second section (27).
3. Device according to claim 2, characterised in that the two sections (26, 27) of the first spring assembly (29) are in the form of spring tongues.
4. Device according to claim 2 or 3, characterised in that the second spring assembly (30) is in the form of a spring tongue (28).
5. Device according to claim 1, characterised in that the first spring assembly (21) is in the form of a two-stage compression spring assembly which may be pressed together by the first plug-in connection element (12) during plugging-in, wherein the first section (22) contacts the first plug-in connection element (12) as the first stage, and the second section (23) as the second stage is designed to make electrical connection between the first section (22) and the first DC voltage contact (19) from a presettable spring pressure onwards.
6. Device according to claim 5, characterised in that the first section (22) is in the form of a coil spring and the second section (23) is in the form of a leaf or cup spring.
7. Device according to claim 5, characterised in that both sections are in the form of coil springs.
8. Device according to claim 5, characterised in that both sections are in the form of leaf or cup springs.
9. Device according to any of claims 5 to 8, characterised in that the second spring assembly (24) is in the form of a compression spring assembly which may be pressed together by the plug-in connection assembly (14) and has spring properties which ensure breaking of the contact at the plug-in connection assembly (14) during unplugging after breaking the electrical connection of the first spring assembly (21) with the first DC voltage contact (19).
10. Device according to any of the preceding claims, characterised in that the magnet coil (11) is in the form of a solenoid of a solenoid valve (10).
11. Device according to claim 10, characterised in that the two plug-in connection elements (14) are located on the casing of the solenoid valve (10).
12. Device according to any of the preceding claims, characterised in that a socket (15; 15') of the plug-in connection assembly (14; 14') is provided on a casing or on an electrical coupling element connected or connectable to a cable.

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