EP0568755B1 - Contact device - Google Patents

Abstract

In the case of a contact device (4) for switching an electrical connection (1) between two live cable elements which overlap in a flat manner, especially in the form of busbars and flat plates, which contact device (4) is arranged between the cable elements and is subjected to pressure, and contains at least one contact-making element (which can be compressed in a resilient manner) as well as at least one supporting element (which is arranged alongside the contact-making element) for limiting the compression of the at least one contact-making element, in order to achieve flexible matching to different connecting geometries, the at least one contact-making element and the at least one supporting element are in each case constructed as a separate contact-making module (5a-d) and supporting module (6a-d) respectively, which can be combined with one another as desired. <IMAGE>

Description

TECHNICAL AREA

The present invention relates to the field of electrical connection technology. It relates to a contact device for arranging an electrical connection between two overlapping, current-carrying line elements according to the preamble of claim 1.

Such a contact device is e.g. known from FR-A-2 339 259.

STATE OF THE ART

In electrical engineering, it is generally known that larger, flat contact surfaces, for example two overlapped busbars, do not ensure a safe current transfer. There are only relatively few contact points on the contact surfaces of such contact rails. In the case of larger currents, these contact points are then specifically overloaded and heat up. Under the elevated temperature there is an accelerated oxidation and thus further deterioration and warming the contact points. Often accidents, especially fires, have to be traced back to such phenomena.

Because of the disadvantages described, various approaches have been taken in practice to eliminate the described uncertainty when combining electrical contact rails. For example, it is known to roughen the contact surfaces on the contact rails or to dissolve them into segments, or to interpose close-meshed grids made of copper sheet or the like or foils. However, even with additional amalgamation of the contact surfaces, this does not lead to satisfactory solutions if mechanical stresses, in particular in the form of vibrations, occur at the same time, which could loosen the screw connections. In addition, intermediate layers made of copper sheet or the like tend to creep, which leads to further loosening of the screws. In the case of arrangements for combining electrical contact connections by means of screw connections, it is known to also interpose spring washers, but the electrical disadvantages mentioned at the beginning occur again.

It has therefore already been proposed to interpose spring washers specially formed when screwing busbars together by means of a screw connection, which have contact elements in the form of contact lamellae connected on both sides to edge strips of the disk body and bent out of the plane of the disk body by inclination around the longitudinal axis and compressed resiliently can be and in their edge contour are preferably designed so that they make a line contact with the power rails.

Problems arise with the use of these known spring washers, however, in that when the connection is assembled, ie when the screws are tightened, the spring travel of the spring washers cannot be set in a defined manner, but only the washer body itself serves as a stop, namely when the contact blades are completely compressed . In DE-OS 25 01 003 to solve these problems it is proposed that on the inner and outer edge of the (circular) spring washers, which have the contact lamellas already described as contacting elements, collars are formed as supporting elements and their height is such that they Limit the mutual distance of the busbars when screwed together to a predetermined value that is greater than the thickness of the spring body.

Such an integrated formation of contacting and supporting elements in a single spring washer has the consequence, however, that the individual contacting device cannot be flexibly adapted to different connection geometries, but rather special washer sizes have to be produced and kept in stock for each application. In addition, the contacting elements are exposed to the ambient conditions to a large extent without protection, so that the actual contacts may continue to be oxidized or otherwise deteriorated. The (known per se) sealing of the contacting elements is, however, made considerably more difficult by the integrated supporting elements.

Similar problems also arise if, as disclosed in FR-A-2 339 259, the contacting elements are designed as straight elements. Although such elements can be flexibly adjusted in length, sealing to the outside is also difficult here because of the integrated, beam-like supporting devices.

PRESENTATION OF THE INVENTION

It is therefore an object of the present invention to provide a contact device which can be flexibly adapted to different connection geometries using support elements and which can also be easily equipped with an additional seal.

In a contact device of the type mentioned at the outset, the object is achieved in that the contacting module (5, 5a-d) and the supporting module (6, 6a-d) each have an outer, closed module frame (7a or 7b).

The essence of the invention is therefore to construct the entire contact device from individual (standardized) contacting modules and support modules, from which large-area contact devices can be assembled in any desired manner by combining or stringing them together. The division into modules with different functions enables both the contacting element and the supporting element to be surrounded separately with a seal in a simple manner.

A first preferred embodiment of the invention is characterized in that the contacting module and support module are designed to be interconnectable. This makes it possible to easily assemble the individual modules into preassembled mats in accordance with the respective connection geometry.

• (a) beim Kontaktiermodul in dem Modulrahmen ein Kontaktblech mit einer Mehrzahl von aus der Ebene des Kontaktbleches beidseitig herausragenden Kontaktlamellen befestigt ist;
• (b) beim Abstützmodul in dem Modulrahmen eine Abstützplatte befestigt ist, deren Dicke kleiner ist als die maximale Dicke über den beidseitig herausragenden Kontaktlamellen, und deren Dicke grösser ist als die Dicke des Kontaktbleches.

A second preferred embodiment of the invention is characterized in that

• (a) in the contacting module, a contact plate with a plurality of contact lamellae protruding from the plane of the contact plate is fastened in the module frame;
• (b) a support plate is attached to the support module in the module frame, the thickness of which is smaller than the maximum thickness above the contact lamellae projecting on both sides, and the thickness of which is greater than the thickness of the contact plate.

The module frames can be designed as a circumferential seal on the inside and have module connecting elements on the outside, in particular in the form of snap-type snap-in elements.

Further preferred embodiments of the device according to the invention result from the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

in perspektivischer Darstellung eine beispielhafte geschraubte elektrische Verbindung zwischen zwei Stromschienen mit dazwischenliegender Kontaktiervorrichtung, auf welche die Erfindung angewendet werden kann;

Fig. 2a

in der Draufsicht eine beispielhafte Anordnung von Kontaktier- und Abstützmodulen für die elektrische Verbindung aus Fig. 1 gemäss einer bevorzugten Ausführungsform der Erfindung;

Fig. 2b

den Querschnitt durch eine mittels Modulverbindungselementen verbundene Kombination aus einem zentralen Abstützmodul und zwei aussenliegenden Kontaktiermodulen gemäss einer bevorzugten Ausführungsform der Erfindung;

Fig. 3a

in der Draufsicht ein einzelnes Kontaktiermodul gemäss Fig. 2a;

Fig. 3b

in der Draufsicht ein einzelnes Abstützmodul gemäss Fig. 2a;

Fig. 4a-c

verschiedene Ansichten und Schnitte eines Kontaktbleches mit herausgebogenen Kontaktlamellen, wie es bevorzugt in den Kontaktiermodulen nach der Erfindung Verwendung findet; und

Fig. 5

die perspektivische Ansicht eines Kontaktbleches nach Fig. 4.

The invention will be explained in more detail below on the basis of exemplary embodiments in connection with the figures. Show it

Fig. 1

a perspective view of an exemplary screwed electrical connection between two busbars with an intermediate contacting device, to which the invention can be applied;

Fig. 2a

in plan view an exemplary arrangement of contacting and support modules for the electrical connection from FIG. 1 according to a preferred embodiment of the invention;

Fig. 2b

the cross section through a combination of a central support module and two external contact modules connected by means of module connecting elements according to a preferred embodiment of the invention;

Fig. 3a

in plan view a single contacting module according to FIG. 2a;

Fig. 3b

in plan view a single support module according to FIG. 2a;

4a-c

different views and sections of a contact plate with bent contact blades, as is preferably used in the contacting modules according to the invention; and

Fig. 5

the perspective view of a contact plate according to FIG. 4th

WAYS OF CARRYING OUT THE INVENTION

The invention will be explained below using the example of a screwed electrical connection between two busbars, as shown in Fig. 1. The electrical connection 1 between the two busbars 2a and 2b is established in that the two busbars 2a and 2b overlap flatly and are screwed together by means of connecting screws 3a and 3b. The connecting screws 3a, b can either be screwed into corresponding threaded bores in the lower busbar 2b or screwed onto the underside of the lower busbar 2b with corresponding nuts.

In order to produce a reliable electrical contact between the busbars 2a, b, a contacting device 4 is arranged between their contact surfaces, which contact device is compressed by the screw connection. According to the invention, the contacting device 4, which preferably extends over the entire contact area, is composed - as shown by way of example in FIG. 2a - of separate contacting modules 5a to 5d and support modules 6a to 6d. The individual modules are available in standardized form and dimensions. They are alternately combined with one another in such a way that the available contact area is covered on the one hand with as many contacting modules 5a-d as possible and on the other hand sufficient support modules 6a-d are distributed over the contact area so that a uniform pressure distribution and support of the screw connection is guaranteed.

In the exemplary connection from Fig. 2a, in which two through holes 14a and 14b are provided for the connecting screws 3a and 3b, a combination of two elongated, rectangular contacting modules 5a, b and 5c, d and two interposed square support modules 6a, b and 6c, d placed. The dimensions of the contacting modules 5a-d are preferably chosen so that that they have an aspect ratio of 3: 1, and the length of the short side corresponds to the side length of the square support modules 6a-d.

The module size itself is determined in such a way that screw connections of busbars with a rectangular cross section according to DIN 43673, part 1 and flat connections for electrical equipment according to DIN 46206, part 2, with a width equal to or greater than 40 mm, are included rated currents mentioned in DIN 43670 and DIN 43671 can be realized. Have proven themselves in practice e.g. Side lengths of 13.33 mm (for the square sides or the short rectangular side) and 40 mm (for the long rectangular side). In addition to the square support modules 6a-d (the so-called 1/3 modules), to increase the flexibility of the system, rectangular "1/1 modules" can also be provided, which have the same outer dimensions as the contacting modules 5a-d. For example, in the arrangement according to FIG. 2a it is conceivable to replace one or more of the contacting modules 5a-d by a corresponding 1/1 support module. Other dimension variants are also conceivable, provided that large-area mats can be built up systematically from them.

The individual modules, the rectangular contact module 5 and the square support module 6, are shown separately in FIGS. 3a and 3b. Each module comprises a rectangular or square, closed module frame 7a or 7b which runs around the outside and in which (in a groove) a contact plate 10 with contact blades 11 is attached in the contacting module 5, and a support plate 12 is fastened in the support module 6. The module frames 7a and 7b are designed to protect the internal elements from the effects of the environment (for example, an aggressive atmosphere) on the inside as a circumferential seal 8 which, when the electrical connection 1 is screwed together, lies closely against the inner surfaces of the busbars 2a, b and thus forms a sealed interior for the contact plate 10 or the support plate 12.

On the outside, i.e. outside the circumferential seal 8, the module frames 7a and 7b preferably have module connecting elements 9 for connecting the individual modules to one another. A preferred exemplary embodiment for such module connecting elements 9 is shown in FIG. 2b, which figure shows a cross section of a combination of an internal support module and two external contacting modules (corresponding to the combination 5a, 6a and 5b from FIG. 2a). The module connecting elements 9 here have the form of snap-button-like snap-in elements 13a or 13b, which allow the individual modules to be snapped together to form a mat. It goes without saying that other types of connecting elements are also conceivable for the fulfillment of the same purpose.

The contacting plates 10 already mentioned, which have a multiplicity of contact lamellae 11, are preferably used as contacting elements within the contacting modules 5 and 5a-d. As can be seen from the illustrations of such a contact plate 10 in FIGS. 4a-c (FIG. 4b: top view; FIG. 4a: longitudinal section; FIG. 4c: cross section) and FIG. 5 (perspective view), the contact lamellae 11 are shown on both sides in Edge strips of the contact plate 10 transitional elements and bent out of the plane of the contact plate 10 by setting about the longitudinal axis. The edges of the contact lamellae 11 are preferably curved in order to achieve line contact. For example, 14 such contact blades 11 can be provided per contact module. A spring alloy can be used as the material for the contact plate 10, and the surfaces of the contact lamella 11 can be silver-plated.

With an exemplary thickness of the contact plate 10 of 0.5 mm and a maximum thickness above the contact lamella 11 projecting on both sides of, for example, 1.6 mm, a brass or copper plate with an intermediate plate is used for the support plate 12 in the support modules 6 or 6a-d Thickness of 1.2 mm selected, so that when screwing the electrical Connection of the contact lamellae 11 can only be compressed by a defined fraction or can be prestressed with a defined spring force.

An elastic, temperature-resistant plastic is preferably used for the module frames 7a, b with their integrated seal 8, so that the seal 8 and module connecting elements 9 can be formed as integral components of the frame.

LIST OF DESIGNATIONS

1

electrical connection

2a, b

Track

3a, b

Connecting screw

4th

Contact device

5.5a-d

Contact module

6.6a-d

Support module

7a, b

Module frame

8th

poetry

9

Module connector

10th

Contact plate

11

Contact lamella

12th

Support plate

13a, b

Snap-in element

14a, b

Through hole

Claims (9)

1. Contact device (4) for providing an electrical connection (1) between two flat-overlapping, current-carrying line elements, particularly in the form of bus-bars (2a,b) and flat plates, said contact device (4) being located between the line elements and subject to pressure action and contains at least one resiliently compressible contacting element and at least one support element, positioned alongside the contacting element, for limiting the compression of the at least one contacting element, the at least one contacting element and the at least one support element being in each case constructed as separate contact modules (5, 5a-d) or support modules (6, 6a-d) from which can be assembled by combination or lining up larger surface contact devices, characterized in that the contacting modules (5, 5a-d) and support modules (6, 6a-d) in each case have an externally all-round, closed module frame (7a or 7b).
2. Device according to claim 1, characterized in that the contacting module (5, 5a-d) and support module (6, 6a-d) are interconnectable.
3. Device according to claim 2, characterized in that

   (a) in the case of the contacting module (5, 5a-d), in the module frame (7a) is fixed a contact plate (10) with a plurality of contact laminations (11) projecting on either side from the plane of the contact plate (10) and

   (b) in the case of the support module (6, 6a-d), in the module frame (7b) is fixed a support plate (12), whose thickness is smaller than the maximum thickness over the contact laminations (11) projecting on either side and whose thickness is greater than the thickness of the contact plate (10).
4. Device according to claim 1, characterized in that the module frames (7a,b) are constructed on the inside as an all-round seal and on the outside have module connecting elements (9), particularly in the form of pushbutton-like locking elements (13a,b).
5. Device according to claim 4, characterized in that the module frames (7a,b) are made from an elastic, heat-resistant plastic.
6. Device according to one of the claims 3 to 5, characterized in that

   (a) the contact laminations (11) are constructed as elements bent out of the plane of the contact plate (10) by setting about the longitudinal axis and passing on either side into marginal strips of the contact plate (10) and

   (b) the edges of the contact laminations (11) are curved for obtaining a linear contact.
7. Device according to one of the claims 3 to 6, characterized in that the module frames (7a,b) have a substantially rectangular shape.
8. Device according to claim 7, characterized in that in the case of the support modules (6, 6a-d), there are module frames (7b) with a square shape and in the case of the contacting module (5, 5a-d) module frames (7a) with an aspect ratio of 3:1.
9. Device according to claim 8, characterized in that module frames (7b) with an aspect ratio of 3:1 are also provided for the support modules (6, 6a-d).

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