Distribution arrangement for telecommunication apparatus

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BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a distribution arrangement for telecommunication apparatus with a safety plug for a contact component part which is provided with a terminal connecting components for incoming and outgoing electrical leads.

2. Description of the Prior Art

A safety plug of the type as referred to herein is generally known, for example, in German Patent Application DE-OS No. 30 14 796. This safety plug has plug-in blades that can be plugged into a terminal strip, as is shown, for example, in German Patent Application DE-OS No. 27 25 551. A terminal strip of this type has corresponding spring contacts that are connected to the electrical leads. The safety plug is provided with surge arresters that are connected with the plug-in blades. A pole of the surge arresters is coupled to a grounding bar which has lateral contact blades that resemble the plug-in blades in kind and in size. The ground potential is conducted to the grounding bar via these contact blades.

It is further known from German Patent Application DE-OS No. 27 20 220 to set the grounding bar directly into the contact component part. The safety plug, in this case, becomes merely a holder for the surge arresters, that are inserted in the contact component part. The grounding bar is connected with a grounded bearing rail for the contact component part, via a bow-type leaf spring. However, a safety plug of this kind has the drawback that, in case a surge arrester must be changed, the entire plug must be removed, so that the leads are not protected during that time.

It is therefore a primary object of the present invention to conduct the ground potential to the safety plug in the simplest and safest possible manner.

A contact arrangement such as is known from German Patent Application DE-OS 36 25 476 includes, with reference to FIG. 1, a flat safety plug with surge protection components to protect subscriber lines that are connected frontally to terminal connecting components of a layer distributor. The terminal connecting components, for their part, are connected with the surge protection components, via plug-in contacts. A curved bearing plate has stamped-out spring legs 21, between which the safety plug is inserted with a contact zone 22. The contact zone is coupled electrically with the protective components that are designed as, eg. surge arresters, so that surges that may occur can be diverted to the grounded bearing plate. The contact points of the spring legs are designed in spherical form, so that a relatively small, point-like contact surface will result.

It is also known from German Patent Application DE-OS No. 23 15 838, to provide the safety plug with a grounding plate on its backside, that rests via contact fingers at any given time against one pole of the surge arresters, and that is contacted on the longitudinal edge on its backside by means of spring fingers of the spring plate carrying the potential, which is held fast to the component-bearing part. This, too, results in a relatively small contact area between the safety plug and the curved spring finger of the grounded component-bearing part.

SUMMARY OF THE INVENTION

In accordance with the present invention, the ground potential is transmitted directly from the component-bearing part to the safety plug. This eliminates the current path via the contact component part, thus eliminating extra sources of trouble. There is therefore no need to provide component parts of any kind in the contact component part for the transmission of the ground potential.

Component parts of this type are provided with or without safety plugs, depending on geographic location. The saving therefore extends to contact component parts that are supplied without safety plugs, as well.

The grounding contact can rest directly against corresponding contact surfaces of the component-bearing part. However, it is also within the scope of the invention for the component-bearing part to be provided with, a contact film of superior contact grade and to contact it with the grounding contact of the safety plug. The safety plug can also be contacted with a bearing rail that is arranged on the other side of the contact component part. The finger-like protruding grounding contact is carried in a guiding channel, which serves simultaneously for the exact positioning of the safety plug relative to the contact component part.

The outside lines of a telecommunication installation can unintentionally come in contact with variably high overvoltages. Modern electronic switching installations are sensitive to even mild surges, which must be diverted as reliably as very strong ones. It is thus important that the contact can not only withstand strong surges, but also has a negligible contact resistance for negligible surges.

Both high and low excess voltages can be repeatedly and reliably deflected with modest construction expenditure. The grounding contact designed as a double contact has a small-area and a large-area contact point. The small-area contact point by reason of the high surface pressure has a negligible contact resistance even with surfaces of low precious-metal content. At the large-area contact point, greater surges are distributed over a larger surface. The greater specific contact resistance in that case does not impair the diversion of strong surges.

A simple form of the spring contact, described in which inner edge of the punched-out opening is free of impurities or oxide film. Because of the high surface pressure, a reliable grounding contact results here, with low contact resistance. The opposite contact is part of a grounded bearing rail for distributor component parts. It is bent into an L-shaped profile. The opening extends substantially to one side of the bent edge, but also to a small extent into the other leg of the bearing rail. The other leg of the spring contact rests flat against said other leg. This results in a large contact area over which the especially high voltage peaks can be diverted quite simply.

The foregoing and other objects and advantages of the invention will become apparent with reference to the description of a preferred embodiment and to the drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a safety plug for a distribution component part.

FIG. 2 a frontal view of the safety plug according to FIG. 1, with a distribution component part and a component-bearing part for the distribution component part, prior to their being assembled.

FIG. 3 is a side view of the parts according to FIG. 2 after being assembled, all in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In accordance with FIGS. 1, 2 and 3, a contact component part 1 is provided with covered terminal connecting components 2 for incoming and outgoing lines of a telephone switching center. The contact component part 1 has contact springs 3 connected to the terminal connecting components 2, which contact springs serve as opposite contacts for the plug-in contacts in the form of plug-in blades of a safety plug 5. However, the plug-in blades 4 are contact parts, which are not illustrated herein in greater detail, but which are connected at any given time with one pole of a surge arrester 6, whose other pole rests against a grounding plate 7 of the safety plug 4.

The grounding plate 7 is bent substantially at a right angle to both surfaces of the safety plug 5 and in the plug-in direction and projects substantially beyond the plug-in blades 4. With its free end, it forms a grounding contact 8 which is electrically coupled with a grounded bearing part 9 for the contact component part 1. The end of the grounding plate 7, which is finger-shaped and designed as a grounding contact 8, is bent at an acute angle, bent back on itself and forms two spring legs, 13, 14, that are flexibly braced against each other within a rectangular opening 10 of the bar-like bearing part 9, as can be seen with reference to FIG. 3.

The bearing part 9 is bent into an L-shaped bar one of whose legs 16 extends in the plug-in direction of the grounding contact 8. The opening 10 is within the bent area. The punched-out opening 10 extends from the bent edge substantially into the other leg 15. The grounding contact 8 projects substantially through the opening 10 and rests with one leg, over a large surface, against the spring leg 14 extending in the plug-in direction, of the bearing part 9. The other spring leg 13 of the grounding contact 8 rests, over a small surface, against the oppositely located inner edge of the opening 10. By means of this double contact, occuring voltage surges can be transmitted in great bandwidth to the grounded bearing part 9 and diverted.

The contact component part 1 has a groove-like guiding channel 11 for the grounding contact 8, so that the latter is protected from touching and kinking. The housing of the safety plug 5 has a projection 12 covering the foot of the grounding contact 8, that can be inserted with little play in the guiding channel 11 of the contact component part 1. The projection 12 and the guiding channel 11 are slanted at an acute angle relative to the plug-in direction, which facilitates the assembly of the two parts.

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