DE1005149B - Detachable contact connection for rooms at risk of explosion - Google Patents

Description

GERMAN

For electrical communications equipment that is used in potentially explosive areas find, there is the problem of designing power plugs or battery plugs for battery-powered devices in such a way that that the contact point and thus the contact spark when connecting to the power supply is in accordance with the guidelines and regulations for rooms at risk of explosion is shielded from the outside area. This problem occurs especially with battery-powered mine radios, where the battery is changed in the mine must become.

The invention relates to a detachable contact connection for rooms at risk of explosion, ins-1 > Special battery connector for mine radios, in which the contact points are protected against the Outside space must be closed before they come into contact with each other. The invention is characterized in that the device contact is also designed as a pin, preferably resilient in the longitudinal direction and also by an insulating annular protective sheath extending beyond the contact is surrounded and that both protective covers when plugged together over the required creepage distance be positively pushed over one another before the mating contacts for contact contact come.

In pursuit of the inventive concept, there is a metal nut in the protective cover for the device contact greater linear expansion (creepage distance requirement) attached, which has a hole for the introduction of the Has plug contact, and is a metallic lock nut in the protective cover of the plug contact attached, whereby to establish the contact metal nut and lock nut up to a stop with each other be screwed. In a further development of the inventive concept, the plug contact can be used against a compression spring to be longitudinally displaceable in its socket in order to always ensure the same contact pressure.

Detachable contact connections for potentially explosive areas, where the contact points through Protective covers are sealed against the outside space before they come into contact with one another, are known per se. Known arrangements have, for example, labyrinth seals or several interlocking rings and indentations, the length of which is greater than the real length of the Connector pin. However, they have a relatively long contact path due to the existing contact sleeves, so that when you pull out the plug, the protective covers are no longer locked approach when the actual arc or spark occurs. In contrast, the invention creates a long crawl path. It also has a

Detachable contact connection
for areas at risk of explosion

Applicant:

C. Lorenz Aktiengesellschaft,
Stuttgart-Zuffenhausen,
Hellmuth-Hirth-Str. 42

Helmut Wilde and Leopold Pracharz, Pforzheim,
have been named as inventors

Wear, slight damage or provision of the contact points as a result of the arc on the Contact pressure itself has practically no effect.

The invention is explained in more detail with reference to the drawing, which shows an exemplary embodiment:

A metal screw 1 is, for example, firmly connected to the device battery. At the head of the metal screw a contact piece 2 is attached to the contact point 3. About the contact piece 2 is a tubular insulating sleeve 4 screwed on or otherwise attached, with a collar 6 against the supports the front end of the insulating sleeve. The metal nut 5 has no contact with the contact part 2. The metal nut 5 has a considerable linear expansion and has a bore for receiving it of the mating contact 10. Parts 1 to 5 form a unitary component and are integral with it connected to the device battery. In the case of power supply units, these parts 1 to 5 would be the socket contact, for example represent.

The connector part connected to the communication device consists of the cable clamp 7, which extends over the jacket of the cable 8 is attached. 9 is the cable core that is soldered into a hole in the cable clamp 7. the Extension 10 of the cable clamp forms the mating contact with contact point 11. On the contact 10 a stop ring 12 is firmly attached. A compression spring 13 rests against the stop ring 12, which on the other side in the flange 14 of a metal part 15 has its abutment. With the metal part 15 an insulating sleeve 16 is firmly connected, which extends a considerable distance to the front beyond the contact 10.

609 866/310

protrudes and covers the cable clamp to the rear. The metal part 15 carries on its front. Side an internal thread which is screwed onto the external thread of the metal nut 5 to establish the contact connection. Part 15 is therefore the lock nut for metal nut 5. When the two parts 5 and 15 are screwed together, the insulating sleeves 4 and 16 interlock positively and shield the contact points 3 and 11, where the contact spark occurs, with long creepage distances from the outside . The creepage distances are marked with K , and their minimum length is determined by the legal requirements. The creepage distance is understood here (e.g. according to VDE 170/71) to be the air gap or the air gap length within which the spark or the arc extinguishes. According to the invention, the sliding path is considerably larger than the extinguishing path. A re-ignition through the air gap of the metal nut 5 is also effectively and reliably avoided, as can be seen from the large creepage path length K (length of the nut) belonging to the nut 5. Only in the last part of the screwing movement, when the lock nut 15 rests against the flange 6 of the metal nut 5, the contact points 3 and 11 touch Springs 13 are arranged longitudinally displaceably within the parts 15 and 16. When loosening the connection, ie unscrewing the screw connection between 5 and 15, the contact is opened first, although the connection itself is still tight, and the plug connection can only be loosened when the counter nut 15 is completely unscrewed. In this way, a contact connection is created that meets all requirements for areas at risk of explosion.

It goes without saying that various changes can be made without affecting yourself to remove from the inventive idea as it is laid down in the claims.

Claims (3)

PATENT CLAIMS: 1. Detachable contact connection for areas at risk of explosion, especially battery connectors for mine radios, in which the contact points are closed off from the outside by protective covers before they come to touch contact themselves, characterized in that the device contact is also preferably a pin is formed resilient in the longitudinal direction and also from one extending beyond the contact insulating annular protective cover is surrounded and that both protective covers when plugged together are pushed over one another in a form-fitting manner over the required creepage distance, before the mating contacts come into contact. 2. Contact connection according to claim 1, characterized in that in the protective cover for a metal nut of greater length (creepage distance requirement) is attached to the device contact is, which has a hole for the introduction of the plug contact, and that in the Protective cover of the plug contact a metallic lock nut is attached and that for the production of the contact metal nut and lock nut are screwed together up to a stop. 3. Contact connection according to claims 1 and 2, characterized in that the plug contact against a compression spring is longitudinally displaceable in its socket to always keep the same contact pressure to ensure Considered publications:
German patent specification No. 446 178. 1 sheet of drawings © 509 866/310 3. 57