AU2003214137B2

AU2003214137B2 - Circuit breaker having double pole interruption

Info

Publication number: AU2003214137B2
Application number: AU2003214137A
Authority: AU
Inventors: Miran Dolinsek
Original assignee: ETI Elektroelement dd
Current assignee: ETI Elektroelement dd
Priority date: 2002-03-18
Filing date: 2003-03-18
Publication date: 2006-03-16
Anticipated expiration: 2023-03-18
Also published as: DE50306378D1; ATE352857T1; CN1653573A; ES2279099T3; WO2003079389A1; EP1488438B1; AU2003214137B9; DE10211905A1; CN100356494C; EP1488438A1; AU2003214137A1

Abstract

The invention relates to a circuit breaker having double pole interruption, comprising a first and second contact device, each of which having a stationary contact (26) and a moving contact (23), whereby both moving contacts (23) are mounted on a supporting body (11) in a manner that enables them to pivot about a common pivot axis (24) while each being pretensioned in their closed position by a contact spring (28). The circuit breaker also comprises a switching lever (21), which is pivotally mounted on the supporting body (11) and is pretensioned by the contact springs (28) of the moving contacts (23) in an interrupt position, in which the switching lever (21) holds the moving contacts (23) in their breaking position. The circuit breaker additionally has a switch actuating element (31) that can be coupled to the switching lever (21) via a coupling device (32, 20), whereby the switch actuating element (31) enables the switching lever (21) to pivot out of its interrupt position and into an enable position against the force of the contact springs (28) and to be held in this enable position as long as the switch actuating element (31) is coupled to the switching lever (21). The coupling device has a coupling element (32), which is coupled to the switch actuating element, and a detent (20), which is pivotally mounted on the switching lever (21) and holds the coupling element (32) in contact therewith or releases it depending on the position relative to the switching lever. Finally, the circuit breaker comprises a trip element (16), which acts upon the detent (20) in the event of a fault whereby causing the detent to release the coupling element (32).

Description

_1 VERIFICATION OF TRANSLATION I Bernhard P. Wagner of ter Meer Steinmeister Partners GbR. Mauerkircherstrasse D-81679 Munich. Germany state that the attached document is a true and complete translation of the patent application for the invention entitled "Automatic Circuit Breaker for the Automatic Interruption", the subject of International Patent Application PCT/EP03/02817 filed on March 18, 2003, to the best of my knowledge.

Signature of translator or other signator Bernhard P. Wagner European Patent Attorne Dated: October 8, 2004 WO 03/079389 Al The invention concerns an automatic circuit breaker with double-pole interruption for the protection of lines against fault currents, in particular against thermal overloading and short circuiting.

Up to now, automatic circuit breakers for alternating current which break the circuit at a single pole have usually been used, at least in central Europe. Since such automatic circuit breakers are usually used in so-called neutralised networks, that is, in network systems in which the neutral conductor is earthed by the energy supply company, interruption of the neutral conductor in household wiring in case of a fault is not necessary.

In the course of globalisation, however, it is becoming more and more difficult to ensure these neutralisation conditions, that is, earthing of the neutral conductor by the energy supplier, across Europe, so that double-pole breaking of the circuits to be protected is already required today for safety reasons in some European countries.

From DE 39 15 127 Cl is known an automatic circuit breaker with single-pole interruption, which has a contact device with a fixed contact and a movable contact which is biassed by a contact spring into its closed position. To switch the switch on and off, there is provided a hand switch which is connected by a coupling device to a switching lever which is biassed by a switching spring into its position separating the two contacts. A latch which is pivotable about the same axis as the switching lever serves to keep the coupling device operatively engaged with the switching lever, so that the switch can be opened and closed manually. An overcurrent tripping device cooperates with the latch to actuate the latch in case of a fault in such a way that the switching lever is released to be pivoted by the switching spring into its position interrupting the contacts. Here, the switching lever must move the movable contact against the force of the contact spring into its interrupt position.

If an automatic circuit breaker of this kind is to be tripped so as to interrupt both poles of a line, then it is not simply possible to double the components of the known automatic circuit breaker, as the functional components of the double-pole automatic circuit breaker are to be accommodated in the volume of a previous single-pole automatic circuit breaker so that no extra changes to the respective switch cabinets or systems are necessary. The main problem here is the overcurrent tripping device, which most of all takes up space and therefore cannot be doubled.

Hence the problem lies in that this overcurrent tripping device does apply the tripping forces for unlatching a single-pole automatic circuit breaker, but does not control the double forces such as are necessary for a double-pole switch.

Overcurrent tripping devices which cause interruption of the line, that is, opening of the contacts both in a short circuit and in case of thermal overload, are known from DE 199 42 694 Al and EP 0 917 173 A2, for example.

It is the object of the present invention to design an automatic circuit breaker with double-pole interruption in such a way that the tripping forces for two contacts to be interrupted can be applied by a single tripping device, so that all functional components of the automatic circuit breaker can be accommodated in the volume of an ordinary single-pole automatic circuit breaker.

This object is achieved by the automatic circuit breaker according to claim 1. Advantageous developments and embodiments of the invention are described in the subsidiary claims.

According to the invention, therefore, an automatic circuit breaker with double-pole interruption includes a first and a second contact device, each of which includes a fixed contact and a movable contact, wherein the two movable contacts are mounted on a supporting body so as to be pivotable about a common pivot axis and are in each case biassed by a contact spring into their closed position, a switching lever which is mounted pivotably on the supporting body and spring-biassed by the contact springs of the movable contacts into an interrupt position in which it keeps the movable contacts in their switched-off position, a switch actuating element which can be coupled by a coupling device to the switching lever so that the switching lever is pivotable by means of the switch actuating element out of its interrupt position against the force of the contact springs into a release position and can be held fast in this position as long as the switch actuating element is coupled to the switching lever, wherein the coupling device includes a coupling element linked to the switch actuating element and a latch which is mounted pivotably on the switching lever and which keeps the coupling element engaged with the switching lever or releases it, depending on the position relative to the switching lever, and a tripping device which in case of a fault acts on the latch in such a way that it releases the coupling element.

According to the invention, therefore, a single spring for each contact point is cleverly used simultaneously as a switching spring, so that the demands for sufficient contact force, opening force and unlatching force for a double-pole switching device are met.

According to an advantageous embodiment of the invention, in this case it is provided that the contact springs are each supported by one end on the movable contact and by the other end on the switching lever.

To achieve particularly suitable adaptation of the individual components to the required volume, it is provided that the switching lever is designed symmetrically to a plane perpendicular to its pivot axis, and that the movable contacts in relation to this plane are arranged symmetrically to each other in the region of the axial outer surfaces of the switching lever, wherein the switching lever in the region of its plane of symmetry has a notch parallel thereto, in which the latch is mounted pivotably.

A particularly appropriate development of the invention is distinguished in that the switching lever, which is substantially sector-shaped about its pivot bearing, has a recess partially extending substantially arcuately about its pivot bearing, and that the pivot axis of the movable contacts is arranged at such a distance from the pivot bearing of the switching lever that it lies within the outer contour of the switching lever in the arcuate recess, wherein in the outer circumferential region of the switching lever for each movable contact is provided a driver element for entraining the movable contacts in case of a fault in their switched-off position.

Here it is particularly appropriate if the contact springs are in each case supported by one end in the region of the outer circumference of the switching lever and by the other end on the movable contact in such a way that the contact springs lie with their end regions facing towards the movable contacts in each case between one of the driver elements and the pivot axis of the movable contacts.

As a result, in the event that the movable contact abuts against the fixed contact while the switching lever is fixed in its release position, the force of the contact spring causes the closing force while at the same time the whole force is also available as an opening force.

To obtain an indication of an automatic circuit breaker which is open on account of a fault current, in another advantageous development of the invention it is provided that on the switching lever is provided a driver spring for the switch actuating element, for moving the switch actuating element into a middle position after tripping in case of a fault, the driver spring being made in one piece with a contact spring.

To obtain particularly good utilisation of the module width of nowadays 18 mm, in a particularly preferred development of the invention it is provided that the tripping device, the contact devices with associated explosion chambers and the switching lever with the associated latch are arranged on the common, T-shaped supporting body symmetrically thereto.

As a result, not only can all the mechanics and electrics of the automatic circuit breaker be made in the conventional module width, but it is also made possible for the complete system to be possible in the open state, that is, without the aid of housing covers.

Further, by using the common supporting body as the base for all functional parts, both a largely toleranceindependent manner of operation and a favourable condition for fully automatic manufacture in mass production are ensured.

The invention is described in more detail below by way of example with the aid of the drawings. They show: Figure 1 a simplified schematic side view of an automatic circuit breaker according to the invention, a side cover being partly broken off to show the functional elements inside, Figure 2 a plan view from below of the automatic circuit breaker according to the invention as in Figure 1, Figures 3a to 3c a side view of the switching and tripping mechanism in different functional positions, and Figures 4a to 4c side views partly in section, corresponding to Figures 3a to 3c, to illustrate switch operation.

In the different figures of the drawings, components corresponding to each other are given the same reference numbers.

As can be seen in Figures 1 and 2, a supporting body with the functional parts located thereon is closed by left and right shell-like covers 11, 12. Here, the supporting body 10 and the two covers 11, 12 are joined together by means of integrally formed rivet pins in a manner not shown in more detail. After installation of the automatic circuit breaker according to the invention in a distributor box or switch cabinet, the part of the housing which is then visible is substantially formed only by the two covers 11, 12.

The automatic circuit breaker according to the invention is equipped with two terminals 13 on the input side and two terminals 14 on the output side (only one of which is shown), which can be designed as either screw or plug-in terminals. In particular in the case of plug-in terminals it is advantageous if, as with the terminal 14 on the output side shown in Figure 1, connection can take place from the front, that is, within view of the fitter, after fixing the automatic circuit breaker to a supporting rail, not shown, in the distributor box or switch cabinet.

For this purpose these terminals 14 designed as plug-in terminals are set back, so that sufficient space is available for connection between a cover plate, not shown, of the distributor box and the terminal 14.

In a recess 15 of the supporting body 10 is arranged, substantially symmetrically to the latter, a tripping device 16 which is preferably designed for thermal and magnetic tripping in case of a fault. For this purpose the tripping device 16 has a bimetal plate 17 for thermal tripping and a coil 18 for magnetic tripping. A tripping plunger 19 cooperates, as can be seen particularly clearly in Figures 4a to 4c, with a latch 20 which is mounted pivotably on a switching lever 21.

The switching lever 21, which, as can be seen particularly well in Figures 3a to 4c, has a substantially sector-shaped outer contour, is mounted pivotably on a journal 22 provided on the supporting body 10, and is designed symmetrically to a plane extending perpendicularly to its pivot axis. The pivot lever therefore has on its side shown as the rear side in Figure 1 the same components as on its front side shown in Figure 1. Furthermore, in Figures 4a to .4c, which show the switching lever 21 in section, it can be seen that it has a notch which is located substantially in the plane of symmetry and in which the latch 20 is held pivotably, and in which the tripping plunger 19 of the tripping device 16 can engage for actuating the latch On both sides of the switching lever 21 a movable contact 23 is mounted pivotably on a pivot pin 24 on the supporting body 10. The switching lever 21 has an arcuate recess 21' which is arranged in such a way that the pivot pin or pins 24 lie or lies in this recess 21', so that a pivot movement of the switching lever is not hindered.

The movable contacts 23 are connected by stranded wires 25 to the respective terminal 13. In its closed position, the movable contact 23 abuts against a fixed contact 26, one of which is connected by the coil 18 to its terminal 14. The other fixed contact, which is arranged on the side of the supporting body 10 to be regarded as the rear side in Figure 1, is directly connected to the associated terminal 14.

Associated with the contact devices consisting of movable contact 23 and fixed contact 26 are in each case explosion chambers 27, of which again only one is shown, arranged on the left or right side of the supporting body I0.

The expert recognises that the functional components described with the aid of Figure 1 are provided in a corresponding manner in inversely symmetrical form on the other side, the right or rear side, of the supporting body Below, only the operation and structure of the components shown in the drawings are therefore described.

A contact spring 28 which simultaneously also serves as an opening spring is supported by one end on a pin 29 provided on the outer circumference of the switching lever 21 and by its other end on the movable contact 23. In order to pull the movable contact 23 away from the fixed contact 26 during a movement of the switching lever 21, to be described in more detail, out of its release position shown in Figure 1 into an interrupt position, an arcuate stop web is provided as the driver element. The driver element may, however, also have any other suitable shape which allows reliable transmission of force from the switching lever 21 to the movable contact 23.

In order to be able to move the switching lever out of its interrupt position into a release position and back by means of a switching handle 31 which serves as the switch actuating element, a coupling element 32 is pivotably linked to the switching handle 31, which is kept in coupling engagement with the switching lever 21 by means of the latch In order to move the movable contact out of the interrupt position shown in Figures 3a and 4a into its closed position, the switching handle 31 is moved anticlockwise. in Figures 3a and 4a so as to move the switching lever 21 clockwise via the coupling element 32 which is kept in coupling engagement with the switching lever 21 by the latch 20. On account of the contact spring 28, the movable contact 23 is entrained until it abuts against the fixed contact 26. During further movement of the switching lever 21 into its locked release position, which is shown in Figures 3b and 4b, the stop web 30 comes away from the movable contact 23, so that the contact spring 28, which is supported by one end on the movable contact 23 and by its other end via the switching lever 21, the coupling element 32 and the switching handle 31 on the supporting body, delivers the full closing force.

In the switched-on state, the flow of current is therefore from the terminal 13 via the flexible stranded wire 23 to the contact device consisting of movable contact 23 and fixed contact 26, and further via the coil 18 of the tripping device 16 to the terminal 7. In case of a fault, either the bimetal plate 18 located in the tripping device 16 or the magnet armature will respond and move the tripping plunger 19 downwards in Figure 1 or to the right in Figures 3a to 4c. As a result, the latch 20 is turned anti-clockwise about its pivot point 20', releasing the coupling element 32. Hence locking of the switching lever 21 in its release position is undone, so that the contact spring 28 now serves as the opening spring which is supported via the movable contact 23, its bearing pin 24 and the fixed contact 26 on the supporting body 10 in order to deliver the opening force, until the stop web 30 strikes the movable contact 23 and pulls it away from the fixed contact 26. Thus the switching lever 21 and with it the movable contact 23 are moved by the contact spring 28, which during tripping serves as the opening spring, into the position shown in Figures 3c and 4c until the switching lever 21 and the latch 20 abut against stops 10a and 10b on the supporting body 10 (not shown in Figures 3a to 4c).

A driver spring 33, which is mounted on the pin.29 on the switching lever 21 and cooperates with a projection 34 on the switching handle 31, turns the switching handle 31 into an intermediate position indicating that the automatic circuit breaker has interrupted the lines as a result of a fault.

In case of a short circuit, that is, higher exciting currents, the tripping plunger 19 of the tripping device 16 is driven so hard by the magnet armature that not only is unlatching performed, as described above, but via a connecting web 35 against which the latch 21 is pushed by the tripping plunger 19 the plunger force is transmitted to the switching lever 21 and hence to the movable contacts 23. In case of a short circuit this results in additional acceleration of the movable contacts 23.

To switch back on, the switching handle 31 must first be turned clockwise to pull the coupling element 32 between the latch 20 and the switching lever 21 until it is latched to the latch 20, as shown in Figures 3a and 4a. Then switching back on takes place as described above.

By using commercial components, for example, the tripping device and the explosion chamber, due to their arrangement on the common supporting body 10 in combination with the switching lever with the latch and the terminals, the result is a transportable unit for mass production.

Since only different magnet coils are necessary for the different nominal current intensities of the automatic circuit breaker, but the rest of the components remain the same, considerable advantages arise for stock-keeping and production.

The combination of the tripping device 16 with the switching lever fitted with a latch and other functional parts forms a largely tolerance-independent arrangement which does not necessitate any adjustments for operation.

On account of the same dimensions of the double-pole automatic circuit breaker compared with the single-pole devices, it is easy in existing switch or distributor boxes in case of system changes to replace single-pole automatic devices with the double-pole automatic circuit breaker according to the invention, without other changes to the switch or distributor boxes being necessary.

A second embodiment of the present invention is described in more detail below with the aid of Figures Sa, 6a, 6b and 7a, 7b. Here, components which are identical with those of the first embodiment are not described again.

In order to move the movable contacts 23 in their interrupt position (see Figures 6b and 7b) in the automatic circuit breaker according to the invention in the second embodiment of the invention, instead of or in addition to the stop web 30 there is provided a striker lever 40 which, as Figures Sa and 5b show, has two striker webs 42 and two guide plates 43 with a holding space 44 formed between them for a guide wall formed on the supporting body 10. The central section 45 of the striker lever 40, which carries the guide plates 43 at one end, has at its other end an extension or lug 46 which with the central section 46 forms a shoulder or step 47. The lug 46 of the striker lever is, like the latch 20, guided in the notch in the switching lever 21.

As can be seen in Figures 6a and 7a, the striker lever is mounted between switching lever 21, supporting body and movable contacts 23 in such a way that with its central section 45 and the extended lug 46 it extends partially round.the bearing pin 24 of the movable contacts 23, while the striker webs 42 abut against a projection 23' of the movable contacts 23.

If the tripping plunger 19 of the tripping device 16 is displaced out of the position shown in Figures 6a and 7a, to the right into the position shown in Figure 7b, first the latch 20 as described in connection with the first embodiment is pivoted so that the coupling element 32 is released. At the same time the latch 20 strikes the striker lever 40 and displaces it in such a way that the movement of the striker lever 40, which is transmitted by means of the striker webs 42 to the movable contacts 23, moves the latter into their interrupt position, as can be seen particularly well in Figure 7b. To ensure during the pivot movement of the movable contacts 23 that the striker webs 42 of the striker lever 40 remain in engagement with the stops 23' of the movable contacts 23, a guide wall held between the guide plates 43 of the striker lever 40 can have a corresponding guide or cam surface.

After the opening movement of the movable contacts 23 has been initiated by tripping plunger 19 and striker lever the switching lever 21 too is moved into its interrupt position, wherein it encounters the striker lever 40 in the central region 45 thereof laterally of the latch 20 and, at the end of the opening movement, fixes the movable contacts 23 in their interrupt position via the striker lever.

According to the second embodiment of the invention, a striker lever 40 via which the tripping plunger 19 of the tripping device 16 acts on the movable contacts 23 is therefore provided as an additional separate element of the switching mechanism. In this way faster opening of the movable contacts can be achieved, so that switching off of the automatic circuit breaker reliably and in time in the case of a short circuit or the like is ensured. To act uniformly on the two movable contacts, the striker lever is designed symmetrically to the centre plane of the automatic circuit breaker.

Claims

1. Automatic circuit breaker with double-pole interruption, with: a first and a second contact device, each of which includes a fixed contact (26) and a movable contact (23), wherein the two movable contacts (23) are mounted on a supporting body (11) so as to be pivotable about a common pivot axis (24) and are in each case biassed by a contact spring (28) into their closed position, a switching lever (21) which is mounted pivotably on the supporting body (11) and spring-biassed by the contact springs (28) of the movable contacts (23) into an interrupt position in which it keeps the movable contacts (23) in their switched-off position, a switch actuating element (31) which can be coupled by a coupling device (32, 20) to the switching lever (21) so that the switching lever (21) is pivotable by means of the switch actuating element (31) out of its interrupt position against the force of the contact springs (28) into a release position and can be held fast in this position as long as the switch actuating element (31) is coupled to the switching lever (21), wherein the coupling device includes a coupling element (32) linked to the switch actuating element and a latch which is mounted pivotably on the switching lever (21) and which keeps the coupling element (32) engaged with the switching lever or releases it, depending on the position relative to the switching lever, and a tripping device (16) which in case of a fault acts on the latch (20) in such a way that it releases the coupling element (32).

2. Automatic circuit breaker according to claim 1, characterised in that the contact springs (28) are each supported by one end on the movable contact (23) and by the other end on the switching lever (21).

3. Automatic circuit breaker according to claim 1 or 2, characterised in that the switching lever (21) is designed symmetrically to a plane perpendicular to its pivot axis, and in that the movable contacts (23) in relation to this plane are arranged symmetrically to each other in the region of the axial outer surfaces of the switching lever (21).

4. Automatic circuit breaker according to claim 3, characterised in that the switching lever (21) in the region of its plane of symmetry has a notch parallel thereto, in which the latch (20) is mounted pivotably.

Automatic circuit breaker according to any of claims 1 to 4, characterised in that the switching lever which is substantially sector-shaped about its pivot bearing has a recess partially extending substantially arcuately about its pivot bearing, and in that the pivot axis (22) of the movable contacts (23) is arranged at such a distance from the pivot bearing (22) of the switching lever (21) that it lies within the outer contour of the switching lever (21) in the arcuate recess (21')

6. Automatic circuit breaker according to. claim characterised in that in the outer circumferential region of the switching lever (21) for each movable contact is provided a driver element (30) for entraining the movable contacts (23) in case of a fault in their switched-off position.

7. Automatic circuit breaker according to claim 6, characterised in that the contact springs (28) are in each case supported by one end in the region of the outer circumference of the switching lever (21) and by the other end on the movable contact (23) in such a way that the contact springs (28) lie with their end regions facing towards the movable contacts in each case between one of the driver elements (30) and the pivot axis (24) of the movable contacts (23).

8. Automatic circuit breaker according to any of the preceding claims, characterised in that on the switching lever (21) is provided a driver spring (33) for the switch actuating element for moving the switch actuating element (31) into a middle position after tripping in case of a fault.

9. Automatic circuit breaker according to claim 6, characterised in that the driver spring (33) is made in one piece with a contact spring (28). Automatic circuit breaker according to any of the preceding claims, characterised in that the tripping device the contact devices (23, 26) with associated explosion chambers (27) and the switching lever (21) with the associated latch (20) are arranged on the common, T- shaped supporting body (10) symmetrically thereto.