PROTECTIVE SWITCH

The invention relates to a circuit breaker which contains both a line protection system (LS section) and a fault current protection system (FI section).

More particularly, the switch lock of the LS section has a catch that can be locked with a pawl body which is pivotably mounted, and a bimetal release and a magnetic release associated with the pawl body for tripping. Similarly the switch lock of the FI section has a pivotable catch, a pawl body, and a permanent magnet release being associated with the pawl body and both the LS section and FI section have contact arms mounted in the housing of the circuit breaker to pivot about a common axis.

Circuit breakers which contain a FI section and a LS section and which therefore ensure, in addition to overload protection, personal protection, are known in various forms. Various proposals have already been made to make the tripping process of the two sections of the circuit breaker dependent on each other. In hitherto known designs,, safety elements operating independently of each other (bimetal tripping devices and magnetic tripping devices for the LS section, and totalizing current transformers and permanent magnet tripping devices for the FI section) are associated with thO LS section and the FI section.

In order to transmit the tripping from the FI section into the US section and vice versa, transmission elements were already proposed previously which penetrate the separating wall between the two parts of the circuit breaker.

Methods are also known of connecting a plurality of line protection switches, during the monitoring of polyphase lines, mechanically to each other by means of operating handles protruding from the housings of the switches, the tripping mechanisms also being connected together. If at least one of the line protection switches, owing to the response of its magnetic tripping device or its bimetal tripping device, operates, the other line protection switches are then also opened. Since only the outer conductors have to be monitored, it is not necessary to associate a complete line protection section (including a switch with mechanical system, magnetic tripping device and bimetal tripping device) with the middle conductor. Hence, it has already been proposed to couple the contact apparatus of a switch associated with the middle conductor mechanically with the contact apparatus of the line protection switch of at least one outer conductor.

A circuit breaker which disconnects all poles is known from DE-B-1 563 919. In this known circuit breaker a transmission member is provided in the form of a slide which is guided in grooves in the side walls of adjacent shell halves.

A disadvantage in this known circuit breaker lies in the fact that the actuating parts of the circuit breaker must be made with extensions which actuate the slide.

A line-protection section, in which the coupling of the contact apparatus of the line-protection switch, with that of the switch for the middle conductor without any modification of the construction of the line protection section is possible, as disclosed in AT-B-378 283. In this circuit breaker with a switch for the middle conductor, which is also known from EPA1-149 441, the moving contact arm of the circuit breaker is coupled by means of a slide guided on the side wall of the housing of the circuit breaker with the movable contact of the switch for the middle conductor. The slide has at least one projection engaging with the movable contact of the switch for the middle conductor, and a shoulder in the form of a pin which is at the same time the bearing pin for the articulation between the contact arm and its actuating member.

A fault-current and line-protection switch with a switch for the middle conductor is known from AT-B-384 120, in which the movable contact arm of the line-protection switch disposed in one part of the housing is coupled with the movable contact arm of the switch for the middle conductor, which is located in another part of the housing, by means of a slide which is guided on a partition wall of the housing. In this known circuit breaker a lever pivotably mounted in the housing is associated with the permanent magnet tripping device of the fault current protection, the release pin of the permanent magnet tripping device lying adjacent to one end of the lever and the other end of the lever, in the ON position of the switch, being locked with a spring-loaded actuating member which has a catch associated with the pawl body of the line-protection switch. In addition, a catch which pivots against the force of the spring associated with it, on the pivoting of the contact arm of the switch for the middle conductor into its closed position, into the correct position for a locking with the lever associated with the permanent magnet tripping device is provided on the slide.

A mechanism for a FI switch combined with a LS switch is known from EP-A-271 669. In this known switch (cf. the last paragraph in column 3 of EP-A-271 669) the FI contact arm is not rigidly coupled with the LS contact arm for common action. In the switch proposed in EP-A-271 669 no contact apparatus is provided in the FI section (cf. column 3, lines 20 to 23 of EP-A271 Furthermore, in the switch of EP-A-271 669 two separate closing levers are provided. In the FI section of the switch in accordance with EP-A-271 669 a disconnection shackle is provided, which is intended to be in an active connection with the tripping lever of the line protection switch, in order, in the case of fault current, to attract the "movement" of the tripping device to actuate the switch lock of the LS section in the sense of a release. Details as to how this intended to take place are not given in EP-A-271 669.

The object of the invention is to provide a circuit breaker of the aforementioned type, in which both overcurrent tripping and fault current tripping take place.

This object is achieved in accordance with the invention in a circuit breaker of the aforementioned type through the fact that the contact arm of the section is rigidly coupled with the contact arm of the FI section for joint movement, and that the catch of the FI section, in the course of its pivotal movement in the case of a fault current tripping, runs up on the pawl body of the section and pivots this in the direction of a tripping of the switch lock of the section.

Through the design of the circuit breaker in accordance with the invention the contact arm of the FI section is also pivoted in the case of a fault current tripping and released from the contact fixed on the housing which is associated with without the switch lock of the FI section having to be tripped.

On the other hand, in the case of a fault current tripping by coupling the catch of the FI section with the pawl body of the LS section, the switch lock of the section is tripped by pivoting the pawl body of the switch lock of the LS section, whereupon the contact arm of the LS section carries with it, i.e. opens, the contact arm of the FI section of the circuit breaker in accordance with the invention. In the circuit breaker in accordance with the invention the situation that the switch lock of the LS section is pivotable under the action of the catch of the FI section. The pawl body of the LS section is pivoted by the pivoting of the catch of the FI section in the case of a fault current tripping so that the switch lock of the LS section releases. This design in accordance with the invention has the advantage that only slight forces act on the switch lock that is accommodated in the FI section of the circuit breaker in accordance with the invention, since the switch lock does not have to absorb the force needed for the closing of the movable contact arm of the FI section. A further advantage is derived from the fact that in both cases of tripping (overcurrent tripping on the one hand and fault current tripping on the other) a reliable release including the switch lock of the section takes place.

In one simple embodiment of the circuit breaker in accordance with the invention provision is made for the contact arm of the LS section to be coupled with the contact arm of the FI section by a pin.

A reliably operating embodiment of the circuit breaker in accordance with the invention is characterized by the fact that a bolt with which the catch of the FI section is associated is inserted in the pawl body of the switch lock of the section, and that the catch of the FI section runs up on the bolt during pivoting, and the pawl body of the LS section is pivoted in a direction such as to bring about a tripping of the switch lock of the LS section.

In this embodiment the pivoting of the pawl body of the switch lock of the section takes place practically without delay and the construction particularly simple.

In a practical embodiment of the circuit breaker in accordance with the invention provision may be made for the pin to be inserted in a contact arm carrier for the contact arm of the FI section and into a carrier shackle of the contact arm of the LS section and for the contact arm carrier and the carrier lug be mounted for pivoting about the axis.

The relockirlg of the switch lock of the FI section is effected particularly simply and reliably, if provision is made for the catch of the switch lock of the FI section to be under the action of a pre-loaded spring which forces the catch about a fixed switch lock axis towards the locking point with the pawl body.

A spatially convenient arrangement is obtained if, in accordance with one proposal of the invention, provision is made for the pawl body to have a preferably finger-shaped extension which is associated with the release pin of the permanent magnet tripping device.

The relocking of the switch lock of the FI section of the circuit breaker in accordance with the invention is effected reliably and without damage, if provision is made for a catch return device in the form of a two-armed lever which is pivotable about a fixed switch lock axis to be installed in the switch lock of the FI section, one arm of which cooperates with an attachment on the contact arm support and the other with a lug on the catch for resetting the catch after a fault current tripping, In this embodiment the catch is raised by the catch-resetting device from the locking point and the pawl body, so that this, under the action of the spring associated with it, can pivot back into the position ready for locking.

Provision is made in a preferred embodiment of the present invention, for the fitting on the contact arm support for the contact arm of the FI section, of a lug which holds a resetting device for the permanent magnet tripping mechanism, in the ON position of the switch lock of the FI section, at & distance from the tripping push-rod of the permanent magnet tripping device. This embodiment may also be characterized by the fact that the resetting device is an angle lever pivotable about a fixed switch lock axis, that the lug on the contact arm carrier engages between the two arms of the angle lever and that a spring is provided which forces the resetting device in the direction of pivoting towards the rod of the permanent magnet tripping device.

The pivoting of the pawl body into the locking position is effected simply and reliably if provision is made for the pawl body to be under the action of a spring, which forces the pawl body so as to pivot it into its locking position.

A preferred embodiment of the circuit breaker in accordance with the present invention is characterized by the fact that a tripping indicator unit with two indicators is mounted for pivoting about a fixed switch lock axis, wherein the tripping indicator unit is subjected to the action of a spring, and that the indicators can be locked with an indicator lock which is coupled with the catch by means of an indicator shackle and that the indicator lock releases the indicators when the catch, in the case of a fault current tripping, pivots under the action of the pre-loaded spring associated with it. In this embodiment it can be seen on the basis of the position of the indicators of the tripping indicator unit whether the combined LS/FI switch has been triggered on account of an overcurrent or of a fault current. In the latter case the indicators of the tripping indicator unit are in fact actuated. In a practical embodiment of the tripping indicator unit provision may be made in accordance with the invention for the indicator lock to be pivotable about a fixed switch lock axis, and is subject to the action of a spring which stresses it so as to produce a locking with the indicators.

in one embodiment of the circuit breaker in accordance with the present invention, provision may also be made for a lug to be fitted on the contact arm carrier, which, on the pivoting of the contact arm into a setting corresponding to the ON position, pivots the indicators until they are locked with the indicator lock.

A simplified design is obtained if provision is made for one arm of the spring stressing the pawl body to engage with the pawl body and the other arm to engage with the indicators and to act on these so as to pivot them into their position indicating a fault current tripping. This spring, associated with both the pawl body and the indicators of the tripping indicator unit, acts as a combined spring and fulfils two duties.

The circuit breaker in accordance with the invention may also be fitted with a testing device for the FI section, which is a test key, test contacts and a test contact spring, one arm of which is associated with the test key, as has often been described previously. In accordance with the invention, provision may be made, in the case of such a circuit breaker fitted with a testing device, for the other end of the test contact spring to be pressed by the contact arm carrier, which is in its setting corresponding to the ON position against the test contact of the testing device associated with it. In this embodiment it is found to be satisfactory if a lug on the contact arm carrier is associated with the end of the test spring and the end, when the contact arm is in the OFF position, adjoins a fixed stop at a distance from the testing contact associated with it.

This preferred embodiment of the testing device of the circuit breaker in accordance with the invention ensures that the testing device can be actuated only when the contact arm has been pivoted into its ON position, since one end of the testing contact spring does not adjoin the contact associated with it when the contact arm is in its setting corresponding to the OFF position.

A particularly favourable kinematics is obtained on switching on, if provision is made for the contact arm to be mounted by means of a longitudinal slot on the fixed pivotal axis in the housing and for the contact arm carrier, which is also mounted for pivoting about the axis, to be supported pivotably about the axis on the contact arm. Here it has been found to be convenient for the axis to be disposed between the pivotal axis and the end of the contact arm associated with the fixed contact on the housing.

A favourable movement and a reliable adjoining of the contact fixed on the housing is also obtained for the LS section, if provision is made for the contact arm of the LS section to be mounted pivotably on the axis by means of a slot and for the carrier shackle, which is also mounted for pivoting about the axis, to be supported for pivoting about an axis on the contact arm. Here an embodiment has proved to be satisfactory in which provision is made for the axis, for pivoting about which the carrier shackle is supported on the contact arm, to be located between the slot of the contact arm and the end of it associated with the contact fixed or. the housing.

Further details and characteristics, as well as advantages, can be seen from the following description of embodiments of circuit breakers in accordance with the invention shown in the attached drawings.

Fig. 1 shows the line-protection section (LS section) of the circuit breaker when the upper shell is removed; Fig. 2 shows the switch lock of the LS section in the ON position; Fig. 3 shows the switch lock of the. LS section in the OFF position; Fig. 4 shows the switch lock of the Lb section with contact position indication; Fig, 5 shows the switch lock of the LS section with contact position indication in the OFF position; Fig. 6 shows the fault current protection section (FI section) of the circuit breaker with the additional shell removed, the insulating plate, insulation foil and permanent magnet tripping device being shown only with broken lines; Fig. 7 shows the switch lock of the FI section with the lock cover plate removed; Fig. 8 shows the switch lock with the associated contact support in the OFF position; Fig. 9 shows the switch lock of the FI section with contact support in the ON position; Fig. 10 shows the switch lock from fig. 9 at the time of fault current tripping; Fig. 1 1 shows an embodiment of the switch lock of the FI section without contact position indication; and Fig. 12 shows the FI section contact arm assembly.

All components of the combined FI/LS switch are installed in a housing which comprises an intermediate shell 44 and two outer shells (not shown in the drawings).

The LS section shown in figs. 1 to 5 has an operating handle 1 pivotably mounted in the housing.

In addition, the LS section contains a bimetal tripping device 27 and a magnetic tripping device 17, the bimetal tripping device 27 acting on a pawl body 6 by way of a tension bracket 13 slidably mounted in the intermediate shell 44 and the magnetic tripping device 17 by means of its anchor Furthermore, an arc extinction chamber 18 with deionisation plates accommodated in the LS section and terminals accessible from the exterior are provided for the connection of lines. The current is carried in such a way that the terminal elbow of the right-hand terminal in fig 1 is connected electrically conductively with the bimetal tripping device 27. The bimetal tripping device is for its part electrically conductively connected by means of a cable to the movable contact arm 5 and, when the contacts are closed, with the magnetic tripping device 17. From the magnetic tripping device a further round cable leads into the FI section, is passed in this with at least one winding over the transducer 43 and finally connected electrically conductively with the terminal elbow of the other (in fig. 1 the left-hand) terminal of the LS section of the switch in accordance with the invention.

The operating handle 1 pivotably mounted in the part of the housing receiving the LS section is stressed by a spring T into the pivoting position shown in figs. 1 and 3 corresponding to the OFF position.

The operating handle 1 is coupled by means of the shackle 2 with a catch 3 of the switch lock of the LS section. The catch 3 is pivotably mounted on a support shackle 4, mounting being by means of a pin 7. The catch U-shaped, the openings for receiving the pin 7 being provided in both arms of the catch 3. A projection 9 is provided on the cross-piece of the catch 3, this, as will be described later, being able to engage behind a shoulder 10 on the pawl body 6 in order to lock the catch 3 with the pawl body 6.

The pawl body 6 is pivotably mounted on the support shackle 4, both the support shackle 4 and the pawl body 6 being placed over a pivotal axis 1 1 fixed in the housing and being pivotable about this. The support shackle 4 is for part connected to the contact arm 5, for example by means of a tubular rivet The axis (tubular rivet 12) about which the support shackle 4 is pivotable in relation to the contact arm 5 is located between the pivotal axis 1 1 fixed in the housing for the pawl body 6, the contact arm 5 and the support shackle and the free end of the contact arm 5 which, in the ON position, lies adjacent the LS section contact fixed in the housing.

The support shackle 4 is U-shaped and is pivotably mounted in the region of its arm on the contact arm 5 by means of the tubular rivet 12. The pin also engages in openings in the arms of the support shackle 4, so that the pin pivotably mounting the catch 3 on the support shackle 4 and the tubular rivet are inserted respectively in two mounting openings of the support shackle that a symmetrical loading is obtained.

A torsion spring 16 is inserted by means of a projection 14 surrounding the mounting opening for the axle 11 in the pawl body 6. One end 16' of the torsion spring 16 is suspended from a hook 41 on the support shackle 4 and the other end 16" of the torsion spring 16 from a hook 6' on the pawl body The torsion spring 1 6 loads the pawl body 6 so that the end of it adjacent to the catch and having the shoulder 10 is moved towards the catch 3.

In the contact arm 5 a mounting opening in the form of a slot 20 (figs.

and 5) is provided, through which passes the pivoting axle 11 fixed in the housing, and by way of which the support shackle 4 and the pawl body with their mounting openings are also inserted.

The anchor 17 of the magnetic tripping device 17 is associated with the end 22 (below, in fig. 2) opposite to the catch 3, and the bimetal strip associated by way of the tension bracket 13, which engages with a squaring of the pawl body 6.

If the pawl body 6 is pivoted under the action of the anchor 17' of the magnetic tripping device 17 or of the tension bracket 13 displaced by the bimetal tripping device 27 opposite to the action of the torsion spring i.e.

counter-clockwise in fig. 2, the projection 9 of the catch 3 comes free of the shoulder 10 on the pawl body 6 and pivots the catch 3 counter-clockwise (in fig.

2), so that the arrangement consisting of the catch 3 and shackle 2 bends. At the same time a tension spring 15 suspended in a hole in the contact arm pulls the contact arm 5 away from the contact fixed to the housing with a pivotal motion about the axle 1 1 fixed in the housing. Thus the switch finally moves into the OFF position shown in fig. 1 and 3.

When the contact arm 5 is pivoted into the OFF position shown in fig.

the catch 3 is again locked on the pawl body 6, since, firstly, the pawl body again pivoted by the torsion spring 16 towards the catch 3 and, secondly, the catch 3 is pivoted by the shackle 2 under the action of the operating handle which is stressed clockwise by the torsion spring incorporated in it, until the projection 9 of the catch 3 engages behind the shoulder 10 on the pawl body Through renewed pivoting of the operating handle 1 counter-clockwise the contact arm 5 is pivoted and the switch again connected.

Through the fact that the support shackle 4 is pivotable in relation the contact arm 5. the support shackle 4 and the pawl body 6 Can be pivoted about a common axis formed by the pivotal axle 1 1 fixed in the housing). At the end of the closing process, when the end of the contact arm 5 associated with the fixed housing contact lies adjacent to it, the contact arm 5 can be pivoted even further about the contact point between the end of it and the fixed housing contact, since the fixed housing pivotal axle 1 1 is received in the slot 20 of the contact arm 5, and hence the contact arm 5 can move in relation to the pivotal axle 1 1.

The pivotal axle 1 1 no longer lies in the ON position at the end of the slot 20 in the contact arm 5 adjoining the pawl body 6, but is located at a distance from this end. The reciprocal association of the parts decisive for tripping, namely the catch 3 and the pawl body 6, is rot altered, since these two parts are mounted not directly on the contact arm 5, but on the support shackle 4, which does not move in relation to the catch 3 and the pawl body 6 on the movement, mentioned above, of the contact arm 5 at the end of the closing process. The position of the end 22 and the squaring 21 of the pawl body 6, which are associated with the anchor of the impact anchor tripping device or the tension bracket 13 of the bimetal tripping device, is then also unchanged.

In the embodiment shown in figs. I, 4 and 5 a contact position indicator 8 is also provided. This contact position indicator 8 is mounted in the housing to pivot about an axis 23 and has a curved part 24 which is associated with an opening in the housing wall and can be seen from the exterior through this opening. The contact position indicator 8 also has a lever arm 8', in which a curved, slot-like recess 28 is provided. The pin 7 which mounts the catch 3 pivotably on the support shackle 4 engages 7 in the recess 28 in the lever arm 8' of the contact position indicator 8. so that this is entrained on the opening and closing of the contact arm 5 and indicates the positions of the contact arm 5, i.e.

the ON position and the OFF position.

The pin 7 which connects the catch 3 to the support shackle 4 protrudes through a slot in the intermediate shell 44 from the part of the housing in which the LS section is received and into an adjacent part of the housing in wMch the FI section of the circuit breaker is accommodated.

The FI section of the switch in accordance with the invention shown in two embodiments in figs. 6 to 1 1 (one with and one without tripping indicators) consists of a contact arm assembly (fig. 12) with a contact arm 36, which is pivotably mounted in the housing by means of a contact arm support and a transformer assembly, comprising a transformer 43, a circuit with a yoke assembly, two terminal elbows 67 and 68 of the terminals of the FI section, a contact support firmly inserted in the intermediate shell 44 with a contact and cables 26 and 38. The cable 26, which connects the terminal elbow of one terminal with the contact support 41, is passed through the (totalizing current) transformer 43 in at least one winding, like the cable from the section. The windings that lead to the circuit 42 and the winding that belongs the permanent magnet tripping device 64, which is shown only with broken lines) are also passed through the transformer.

A testing device is provided in the FI section of the switch in accordance with the invention. The testing device has a testing key 80, through the pressing of which one end 83 of a testing spring 82 can be moved to lie adjacent the testing contact 81. The other contact 85, connected to the testing line associated with the other end 84 of the testing spring 82, which pivoted in a manner still to be described on the pivoting of the contact arm of the FI section by the contact arm support 35 adjoining the testing contact By pressing the testing key the testing spring 82 switches the testing resistor 86 between the outer conductor and the neutral conductor.

By means of the pin 7, which engages in the support shackle of the switch lock and is pressed into the contact arm support 35 of the FI section, the switching movement of the LS section is carried out by means of the operating handle 1, shackle 2, catch 3 and support shackle 4 on the contact arm the contact arm support 35 and thus transmitted to the N contact arm supported by this. The N contact arm 36 is connected by means of the cable the stop 39 and the terminal elbow 68, The test contact 85 is also connected by means of the testing resistor 86 to the terminal elbow 68.

The FI switch lock, which is installed at the top on the left in the FI section and which co-operates with the LS switch lock in a manner yet be described, comprises two plates, namely a lock installation plate 29 and a lock covering plate 30 not shown in figs. 7 to 1 1.

The N contact arm 36 is secured on the contact arm support pivot about an axis formed by a bolt 66, the N contact arm 36 and thus the contact arm support 35 being drawn into the open position shown in fig. 6 (OFF position, fig.

by a switch spring 37.

The contact arm support 35 is mounted to pivot about an axis fixed in the housing (bolt 70 which is integrally formed with the bolt forming the pivotal axis of the contact arm 5 of the LS section and may be fixed in the intermediate shell 44) and is located, in the direction of viewing as shown in fig. 6, below the lock mounting plate 29, i.e. between this plate 29 and the partition wall of the intermediate shell 44 which separates the LS section from the FI section. The bolt 60 passes through a slot in the contact arm 36.

The following components are accommodated between the plates 29 and of the switch lock of the FI section: a catch 31 which can pivot about the axis fixed in the housing, about which the contact arm support 35 is also able to pivot, a pawl body 32, which is subject to the action of one arm 56' of a pawl body spring 56 ("combination spring") which actuates by means of its other arm the indicators 33 and 34 of a tripping indicator unit which are mounted to pivot about an axis in the switch lock. The pawl body 32 is stressed counter-clockwise by the arm 56' of the spring 56 associated with it and the indicators 33 and 34 by the arm 56".

The pawl body 32 has a finger-shaped end 32' which is associated with the push-rod 51 of the permanent magnet tripping device 64.

In addition, a resetting device 49 for the push-rod 51 of the permanent magnet tripping device 64 is provided pivotably and subject to the action of a spring 50 in the switch lock of the FI section. The resetting device 49 (shown in fig. 7 in its position assumed before incorporation of the FI switch lock assembly) has a sleeve 62 extending over an axle 61 and two arms 70, 71, between which a lug 72 of the contact arm support 35 engages, so that the resetting device 49 is raised by the push-rod 51 in the ON position shown in fig.

9. The resetting device 49, in the event of tripping, is pivoted under the action of the resetting spring 50 into the position shown in fig. 8, so that the permanent magnet tripping device 64 is reset by the arm 71 associated with its push-rod 51.

Between the plates 29 and 30 of the switch lock of the FI section a further catch resetting device 48 with two arms 76, 77 is mounted to pivot about an axle 74. The arm 76 co-operates with a lug 75 on the contact arm support The other arm 77 is associated with a lug 78 of the catch 31.

A lug 31' pointing towards the intermediate shell 44 and which associated with a bolt 69 which is inserted in the pawl body 6 of the switch lock of the LS section and protrudes through an arc-shaped slot in the intermediate shell 44 is provided on the catch 31.

In order to actuate the indicators 33 and 34 of the tripping indication device together with the catch 31, an indicator shackle 54 is provided which coupled with a pivotable indicator lock 55. The indicator lock 55 acts together with the indicators 33 and 34. In the OFF position the indicator 34, which engaged in the indicator lock 55 coupled by means of the indicator shackle with the catch 31 is before the observation window in the housing. In this case one arm 56“ of the pawl body spring 56 acts on the indicator combination and 34. During the switching-on process the contact arm support 35 moves the indicators 33, 34 by means of a lug 90 provided on it, if the indicator was visible, back into the position in which the indicator 34 is visible, this indicator setting being secured by the indicator lock 55 and the indicator combination 34 is held by the pawl body spring 56 against the lug on the indicator lock In the OFF position shown in fig. 8 (see also fig. 6) the catch 31, coupled by means of the catch resetting device 48 is pivoted beyond the locking point. In this case the force acting in the opposite direction (FS in figs. 8 to 10) of the preloaded spring 46 (fig. 6) is overcome and the latter thus pre-tensioned. The arm 71 of the resetting device 49 for the permanent magnet tripping device forced by the resetting spring 50 towards the push-rod 51 of the permanent magnet tripping device 64 and shifts this into its initial position. The tripping indicating device shows the indicator 34 which is locked with the indicator lock coupled by means of the indicator shackle 54 with the catch 31. The pawl body spring 56 acts on the pawl body 32 and the indicator combination In this position the contact arms 36 (FI section) and 6 (LS section) are held in the OFF position by the contact springs 37 and 15 respectively.

On switching on (pivoting of the contact arms 36 and 6 from the OFF position into the ON position as in figs. 9 and 2 or 4) the switching movement of the LS section is transmitted by way of the pin 7 to the contact arm support The catch resetting device 48 releases the catch 31, so that the catch pivoted under the action of the pre-loaded spring 46 into the position in which is locked with the pawl body 32. The contact arm support 35 pivots the resetting device 49 by the action of its lug 72 on one arm 70 of the resetting device that its other arm 71 is raised by the push-rod 51 of the permanent magnet tripping device 64. If the indicator 33 was visible, the indicator combination and 34 of the tripping indicating device is pivoted by the lug 90 of the contact arm support 35 back into the locked position in which the indicator 34 is visible through the window in the housing.

As described above, the operating handle 1 locks in the ON position after passing beyond the dead centre position (knickle joint-knob-shackle). The two contact arms 6 and 36 are pressed by means of the contact springs 15 and (the force of the spring 37 is represented in fig. 8 to 10 by "FK") with the necessary contact pressure against the fixed contacts on the housing (here the mounting of the contact arms 6 and 36 by mean of their slots is, as described above, of importance).

Fig. 1 1 shows an embodiment of the FI section without a tripping indicator. In this embodiment the combined pawl body spring 56, which acts on the pawl body 32 and the indicator combination 33, 34, is replaced by a single pawl body spring 57. This support spring 57 is placed with at least one winding on the lock plate 29 by way of a pin 6T and supported on a further pin 61" Two examples of tripping processes of the switch in accordance with the invention are described below.

Overcurrent tripping The bimetal tripping device 27 or the magnetic tripping device 17 of the section act on the pawl body 6 of the switch lock of the LS section and pivot this so that the catch 3 is released and the contact spring 15 pivots the movable contact arm 5 of the LS section and, by means of the pin 7, also the contact arm support 35 and thus the N-contact arm 36, supported by the contact spring into the OFF position. The contact arm support 35 pivots so that the permanent magnet resetting device 49 can pivot counter-clockwise under the action of its resetting spring 50 and, in doing so, is brought into the position corresponding to the OFF position (see fig. 8).

The catch 31 and the pre-loaded spring 46 are also brought into the OFF position in the last third of the disconnection movement by the contact arm support 35 and the catch resetting device 48. In the case of overcurrent tripping the catch 31 remains locked with the pawl body 32 and the indicator lock holds the indicator combination 33, 34 firmly, so that they are not pivoted by the spring 56. It can thus be seen from the position of the indicators 33/34 and 24 that an overcurrent tripping (or a manual switching off by operating the operating handle 1) has taken place.

Fault current tripping In the case of fault current the pawl body 32 is pivoted under the action of the push-rod 51 of the permanent magnet tripping device 64 moving to the left in fig.

which acts on the finger-shaped arm 32' of the pawl body 32. Through this the catch 31 is released (see fig. 10) and pivots under the action of the preloaded spring 46 and, actuated by the pre-loaded spring 46, transmitting the tripping action to the bolt 69 pressed into the pawl body 6 of the LS section (i.e.

the pawl body 6 is pivoted) and thus to the switch lock of the LS section. This now trips and the pin 7 also moves the N contact arm into the OFF position.

In this case the indicator lock 55 is also pivoted by means of the indicator shackle 54 and releases the indicators 33, 34, whereupon the pawl body spring 56 can pivot the indicators 33, 34 so that the indicator 33 becomes visible and shows that a fault current tripping has taken place. The other movements during the switching-off process correspond to the procedures in the case of overcurrent tripping given above.

The ionized gases formed by the arc light on switching off in the FI section of the switch are deflected by the attachment 100 of the lug 39 acting as an arc conductor into a channel 101 at the lower edge of the intermediate shell 44 and emerge from this channel 101, substantially cooled, through the openings 102, on the right in fig. 6, of the channel 101 into the open.

To summarize, the invention may be represented, for example as follows.

A circuit breaker has a LS section and a FI section. The switch lock of the section has a pawl body which can be locked with the catch and which cooperates with a bimetal tripping device and a magnetic tripping device for tripping (the overcurrent case). The switch lock of the FI section has a catch and a pawl body 32, with which is associated a permanent magnet tripping device with a tripping push-rod 51. The contact arm of the LS section and the contact arm 36 of the FI section are mounted for pivoting about a common axis in the housing of the circuit breaker. The contact arm of the LS section coupled with the contact arm 36 of the FI section for common movement by a pin which is inserted in a contact arm support 35 for the contact arm 36 of the FI section. A bolt 69 is inserted into the pawl body of the switch lock of the section, said bolt being associated with the catch 31 of the FI section so that this runs on the bolt 69 when it is pivoted in the case of a fault current. Through this the pawl body of the LS section is pivoted so as to trip the switch lock of the section.