EP1360709B1 - Switching contact arrangement - Google Patents

Description

The present invention relates to a switching contact arrangement comprising a contact carrier and a contact lever pivotable about a pivot point on the contact carrier and a leaf spring designed as a contact force spring for pressing the contact lever to a mating contact.

A switch contact arrangement of this type has become known as part of a low-voltage circuit breaker by US Patent 5,517,164.

The force acting on the switching contacts of circuit breakers contact force is applied by the fact that the mentioned contact force springs are tensioned during switching. This is done by a belonging to the circuit breaker drive device whose switching path over the intended life of the circuit breaker is substantially constant. In contrast, increases by burning the switch contacts the way the contact lever, whereby the contact force decreases according to the burnup. If it is to be ensured that a sufficient contact force is achieved even towards the end of the service life of a switching contact arrangement, a suitable dimensioning of the contact force springs can lead to an undesirably high contact force in the new state of the switching contact arrangement. This results in a correspondingly high energy requirement of the drive device.

The present invention has for its object to provide a circuit breaker in which the contact force is less dependent on the burning of the contacts.

With the invention, this object is achieved in a switch contact arrangement of the type mentioned in that the contact force spring is pivotally arranged like a rocker, such that the ends of the contact force spring abut the contact lever and a pivot bearing of the contact force spring between the pivot point of the contact lever and its contact-forming end portion is arranged ,

The contact force of the switching contact arrangement according to the invention does not follow the known characteristics of a helical compression spring or a one-armed leaf spring according to the above US 5,517,164 , Rather, the dependence on the contact erosion is largely reduced and can be largely eliminated by optimized design of the geometry. The determination of the contact force is essentially by a suitable choice of bias. This eliminates the need for oversizing the contact force spring and the drive device, which affects the life of the circuit breaker low.

Preferably, the pivot bearing of the contact force spring without fixed connection with the contact carrier in response to the respective spring force along a sliding surface located on the contact carrier is movable. Due to the non-stationary storage, the bearing point of the leaf spring assembly changes depending on the position of the contact lever.

It proves to be advantageous if the pivot bearing of the contact force spring is formed by a voltage applied to the substantially flat sliding surface on the contact carrier kink of the contact force spring.

In order to ensure a defined force effect in spite of the relative to the contact carrier displaceable pivot bearing of the contact force spring, it is advisable to restrict the relative movement of the contact force spring to the contact lever or to refer to a specific point. This can be achieved that is provided as an abutment of the contact force spring sitting on a contact carrier Gleitbutzen. Likewise, it proves to be well, if one end of the same is bent to form an abutment of the contact force spring and a recess is arranged for receiving the bent end on the contact lever.

As mentioned in the introduction, it is the concern of the invention to keep the energy consumption for the actuation of the switching contact arrangement of a circuit breaker low. For this purpose, it may be contributed by the fact that offset protrusions are provided on the contact carrier and the contact lever in such an arrangement that the spring force increases when switching contact arrangement against the end of the switch-on. This has the consequence that the driving force to be supplied by a drive device increases less sharply when touching the contact lever with its mating contact and already existing kinetic energy can be used to achieve the required voltage of the contact force springs in the on state of the switch contact arrangement.

The inventive design of a switching contact arrangement is particularly suitable for circuit breakers with high rated current, which have several contact levers in each pole. The manufacture and assembly of the corresponding number of contact force springs can be simplified in that the contact force springs of all contact levers are part of a one-piece leaf spring.

In the following the invention will be explained in more detail with reference to embodiments illustrated in the figures.

FIG. 1 shows a switching contact arrangement with a plurality of contact levers partially in a section II-II in FIG. 2 ,

FIG. 2 shows the switch contact arrangement according to the FIG. 1 overlooking the parallel contact lever.

FIG. 3 is a detail shown on an enlarged scale of the switch contact arrangement according to the Figures 1 and 2 ,

The FIGS. 4, 5 and 6 show a further embodiment in illustrations showing the FIGS. 1, 2 and 3 correspond.

FIG. 7 shows a leaf spring having contact force springs for a plurality of contact lever in a perspective view.

The in the FIGS. 1, 2 and 3 illustrated switching contact arrangement comprises a contact carrier 1 which is mounted in a pivot bearing, not shown, by means of bearing journals 12. Contact lever 2 are pivotally connected to the contact carrier 1 about a pivot point 11. The contact lever 2 have a contact-making end portion 18 and are connected at the opposite end by merely indicated flexible conductor 13 electrically conductive with a lower connecting rail 4. Between the contact carrier 1 and the contact levers 2 there are rocker-like contact force springs 8, which are for ensure that the contact-making end parts 18 of the contact lever 2 in the switched-on state of the switching contact arrangement abut with sufficient contact force against a mating contact 5 which carries an arcing horn 3. In known manner, the mating contact 5 may be formed by one end of an upper connecting rail arranged parallel to the lower connecting rail 4.

In the FIG. 1 is also shown schematically a known drive device 6, which acts by means of a lever chain 7 on the contact carrier 1 and brings this in the on or off position. Together with protective and control devices not shown, said assemblies form a low-voltage circuit breaker 22, as indicated by a dot-dashed frame.

Although the contact force springs 8 of the individual contact lever 2 may be individual, designed as a leaf spring parts, but are part of a contiguous, ie one-piece leaf spring. How closer the FIGS. 1 and 3 can be seen, the contact force springs 8 have an approximately centrally disposed bend 20, which forms a pivot bearing 10 together with a formed on the contact carrier 1 sliding surface 19. Essential to the desired function of the switching contact arrangement is the position of the pivot bearing 10 between the pivot point 11 of the contact lever 2 and an upper end leg 14 of the contact force spring 8. This end leg 14 is located on the contact-making end portion 18 of the contact lever 2, while an approximately equally shaped end leg 14 on opposite end of the contact force spring 8 abuts on the contact lever 2 approximately where the pivot point 11 is located. This arrangement has the property that the contact force between the contact-making end portion 18 and the mating contact 5 is largely independent from the relative position of the contact lever 2 to the contact carrier 1 is. Accordingly, the influence of the burnup of the co-operating pads on the magnitude of the contact force is small.

To ensure that the required contact force is formed, the position of the upper angled end portion 14 of the contact force spring 8 is essential given dimensions and properties of the cooperating parts. For this purpose, a mounted on the contact carrier 2 Gleitbutzen 9 is provided. The pivot bearing 10 of the leaf spring assembly 8 is freely movable without firm connection with the contact carrier 1 along the sliding surface 19 and depending on the voltage of the contact force spring 8 only limited by serving as an abutment Gleitbutzen. 9

It should also be mentioned that the illustrated arrangement of the rocker-like contact force spring 8 is located in the space between the abge5 contacts the contacts of the contact lever 2 and the contact carrier 1 and is thereby protected against the effects of switching arcs.

The in the FIGS. 4 to 7 shown further embodiment of a switching contact arrangement with a plurality of contact levers 2 (multi-contact system) differs in the features described below from those of the in the FIGS. 1 to 3 from the example shown. With regard to the remaining embodiment is based on the description of the embodiment of the FIGS. 1 to 3 directed.

While in the first embodiment of the invention, the Gleitbutzen 9 serves as a means for positioning the rocker-like contact force spring 8 is in the in the FIGS. 4 to 7 illustrated second embodiment of the invention, the upper end leg 14 angled in the direction of the contact lever. The contact lever 2 are provided with a recess 15, in which the end leg 14 engages. As a result, the contact force springs 8 are aligned with respect to the associated contact levers. As in the embodiment according to the FIGS. 1, 2 and 3 the desired contact force is achieved by the installation of the contact force springs 8 in the switch contact arrangement with a certain bias.

The formation of several contact force springs 8 as a one-piece leaf spring 23 is closer from the FIGS. 5 and 7 seen. It leaves the FIG. 5 recognize that the leaf spring 23 is behind the contact levers. The assembly is simple and can for example be such that the leaf spring 23 is pressed into the gap after the assembly of contact carrier 1 and contact levers 2 until the angled end portions 14 engage in the recesses 25.

To reduce the energy requirement when switching on a circuit breaker, it may be desirable that the contact force is increased to a desired value shortly before the end position of the contact lever when switching. To achieve this goal are as clear in the 4 and FIG. 6 recognizable, provided on the contact carrier 1 and the contact lever 2 projections 16 and 17, which are offset from each other and are arranged such that the spring force is increased towards the end of the switch-on.

LIST OF REFERENCE NUMBERS

1

contact support

2

contact lever

3

Arc horn on the mating contact 5

4

lower connecting rail

5

countercontact

6

driving device

7

lever chain

8th

rocker-like contact force spring

9

sliding core

10

Swivel bearing of the contact force spring

11

Pivot of the contact lever. 2

12

Spigot for pivot bearing

13

flexible current bands

14

Angled end leg of the contact force spring. 8

15

Recess on the contact lever. 2

16

Projection on the contact carrier 1

17

Projection on the contact lever 2

18

contacting end part of the contact lever 2

19

Sliding surface on the contact carrier 1

20

Kink of the contact force spring 8

21

Switching contact arrangement

22

breakers

23

Leaf spring with several contact force springs 8

Claims (7)

1. Switching contact arrangement having a contact mount (1) and a contact lever (2) which can move in an articulated manner about a rotation point (11) on the contact mount (1), as well as having a contact force spring (8), which is in the form of a leaf spring, for pressing the contact lever (2) against an opposing contact (5),
   characterized
   in that the contact force spring (8) is arranged such that it can pivot like a rocker, such that the ends (14) of the contact force spring (8) rest on the contact lever (2), and a pivoting bearing (10) of the contact force spring (8) is arranged between the rotation point (11) of the contact lever (2) and its contact-making end part (18).
2. Switching contact arrangement according to patent claim 1,
   characterized
   in that the pivoting bearing (10) of the contact force spring (8) can move along a sliding surface (19), which is located on the contact mount (1), as a function of the respective spring force, without any fixed connection to the contact mount (1).
3. Switching contact arrangement according to one of the preceding claims,
   characterized
   in that the pivoting bearing (10) of the contact force spring (8) is formed by a kink (20), which rests on the essentially planar sliding surface (19) on the contact mount (1), in the contact force spring (8).
4. Switching contact arrangement according to one of the preceding claims,
   characterized
   in that a sliding core (9) which is seated on the contact mount (2) is provided as an opposing bearing for the contact force spring (8). (Figure 2 and Figure 3).
5. Switching contact arrangement according to one or more of claims 1-4,
   characterized
   in that, in order to form an opposing bearing for the contact force spring (8), one end (14) of it is bent, and a recess (15) is arranged on the contact lever (2) in order to hold the bent end (14). (Figures 4, 6, 7).
6. Switching contact arrangement according to one of claims 1-5,
   characterized
   in that projections (16, 17) which are opposite one another with an offset on the contact mount (1) and on the contact lever (2) are provided, arranged in such a way that the spring force during connection of the switching contact arrangement rises toward the end of the connection movement. (Figure 4 and Figure 5).
7. Switching contact arrangement according to one of the preceding claims,
   characterized
   in that, if the switching contact arrangement (20) is in the form of a multiple contact arrangement, the contact force springs (8) of all the contact levers (2) are a component of an integral leaf spring (23).

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