EP2634788A1 - Circuit breaker with a latching mechanism - Google Patents

Abstract

The circuit breaker has a latch (1) including a switching mechanism (2) for opening and closing a switching contact. An unlatching mechanism (3) changes a tensioning element from a tensioned state to a largely untensioned state based on a tripping signal to open the switching contact. The tensioning element is linked to a tensioning lever (5) including a locating surface on which a locking pawl (8) of the unlatching mechanism bears in the tensioned state of the tensioning element. The locating surface is curved in a direction of the locking pawl and movably arranged relative to the lever.

Description

The invention relates to a circuit breaker with a switching mechanism. A generic switch lock comprises a switching device for opening and closing a contact element which is in effect with a clamping element and a unlatching mechanism, by means of which the clamping element can be converted from a stressed state into an at least largely unrestrained state on the basis of a triggering signal.

Circuit breakers are special switches that are usually designed for high currents. These switches can not only switch operating currents and low overload currents, but also switch on high overload currents and short-circuit currents if faults occur, hold these fault currents for a predetermined time and then switch them off again. Depending on the embodiment, circuit breakers are single-pole or multi-pole.

Such circuit breakers regularly have so-called switching locks, which cause the switching off of a circuit when unwanted operating conditions, in particular short circuits, occur.

A switch lock represents a mechanical device, which preferably enables the switching off of a circuit. For this purpose, the force of a tensioned spring is usually released to open the switch contact, which has been stretched when switching on a clamping mechanism. The typical trigger criterion is a current of a predetermined current, through which the lock is released by means of an electromagnet or a heating bimetallic strip.

The circuit breaker of a circuit breaker has two main areas. On the one hand is a switching mechanism provided, acted upon by the spring force, the opening and closing of an electrical switching contact is realized. On the other hand, such a switching mechanism has a Entklinkungsmechanismus that releases the energy stored in a spring of the switching mechanism upon reaching a triggering criterion, whereby the switching mechanism is triggered and the electrical switching contact is opened.

The problem with the known from the prior art switch locks is often that provided within the Entklinkungsmechanismus pawl in the locked state with a flat surface of the outer contour of the spring operatively connected to the clamping lever is brought into contact. Since the pawl during operation of the circuit breaker in this way repeatedly touches the same area of the stop surface of the clamping lever, it comes here with increasing operating time to wear. Due to this abrasion on the stop surface, the direction of the normal force and thus also the torque introduced via the pawl into the stop face of the clamping lever change. An increase in torque in this area in turn has the consequence that increases the force required for triggering the switching mechanism. Although it is conceivable to reduce wear by using materials of higher hardness or by using surface treatment methods, this would increase the manufacturing costs of a corresponding component. Another way to reduce the abrasion on the stop surface, is to realize a full-surface contact between pawl and stop surface of the clamping lever. However, this has the disadvantage that the lever arm of the normal force, so the distance between the normal force vector and the force-introducing portion of the pawl, may vary, which would lead to variations in the force required for triggering the switching mechanism.

Based on the known from the prior art switch locks for circuit breakers and the described The problem of the invention is the object of developing a Entklinkungsmechanismus a switching mechanism such that within a limited space, the force of the switching mechanism is minimized by the largest possible factor. Here, the decoupling mechanism to be specified should be characterized by a high release safety, which should be ensured, above all, by a low degree of friction within the unlatching mechanism. Essential for a high release safety on the one hand, that the release force is not too large and on the other hand, the release force remains approximately constant even after prolonged operation of the switch lock. In particular, it should be ensured that the triggering of the switching mechanism is possible regardless of the force in the switching mechanism. Furthermore, the unlatching mechanism should be designed such that the switch lock can be used both for single-pole switches, in which only small forces in the switching mechanism, as well as multi-pole switches with high forces in the switching mechanism.

The above object is achieved with a circuit breaker with switching mechanism according to claim 1. Advantageous embodiments of the invention are the subject of the dependent claims and will be explained in more detail in the following description with partial reference to the figures.

The invention relates to a circuit breaker with a switch lock, on the one hand has a switching device for opening and closing a standing with a clamping element operatively connected switch contact and on the other hand a Entklinkungsmechanismus, on the basis of a trigger signal, the clamping element from a tensioned in an at least substantially unstressed state can be converted, that the switching contact is thereby opened. The tensioning element is coupled to a tensioning lever, which is locked by a detent pawl of Entklinkungsmechanismus abuts against a stop surface of the tensioning lever and prevents it from moving, so that the spring element in tensioned Condition is maintained. According to the switching mechanism has been developed such that the stop surface is curved and arranged to be movable relative to the clamping lever.

The execution of the abutment surface with a curved in the direction of the pawl outer contour at the same time movable mounting of the stop surface has the advantage that no flat contact surface between the pawl and the clamping lever exists, the pawl when triggering the switching mechanism relatively low friction moves over the stop surface and so Wear phenomena are minimized. In particular, it is ensured in this way that the pawl with different areas of the stop surface can be brought into contact and preferably only rolling friction between pawl and stop surface is formed.

In a specific embodiment of the invention, the outer circumferential surface of a roller forms the stop surface. The roller is preferably rotatably mounted on the clamping lever. In the locked state of the switching mechanism, the end of the pawl contacts the abutment surface, ie the outer peripheral surface of the roller. Once the switch lock triggers, the pawl is moved so that the force introduced via the pawl in the role of the clamping lever decreases, so that finally sets the clamping lever in motion and rolls the end of the pawl over the outer peripheral surface of the roller. The resulting friction is minimal.

The storage of the above-described role of a unlatching mechanism can preferably be done in two different ways. In a first specific embodiment of the invention, the clamping lever is made in one piece and the roller rotatably mounted in a suitable recess by means of a bearing pin. In contrast, an alternative design provides that the clamping lever is designed in several parts, wherein in particular two planar-parallel plates, which are contoured in a suitable manner, are provided, and between these sheets, the roller is rotatably mounted about a bearing pin.

According to another specific embodiment of the invention, it is conceivable that the stop surface and / or the free end of the pawl is provided with a surface coating. Preferably, such a coating has a high wear resistance or ensures that the friction between the end of the pawl and the stop surface is at least minimized. If a roller whose outer peripheral surface forms the abutment surface is provided, it can be designed either as a sheet metal or as a plastic roller (ceramic materials, etc.). In a preferred manner, the roller is manufactured as a turned part.

The switching mechanism embodied according to the invention is therefore characterized in particular by the fact that in the unlatching mechanism, a stop surface curved in the direction of the free end of the pawl and movably arranged relative to the tensioning lever is provided. Preferably, in the locked state of the lock, a roller whose outer peripheral surface forms the abutment surface is engaged with the end of the pawl. The solution according to the invention is characterized in that, despite the comparatively small size, the release force required for triggering the lock is minimized. The switching mechanism designed according to the invention can thus be used in the same way for both single-pole and three-pole or four-pole switches. This is primarily due to the fact that the function of the unlatching mechanism is at least largely independent of the force in the switching mechanism.

Due to the movable stop surface on the clamping lever, preferably a roller, the friction that arises when slipping the pawl from the clamping lever, compared to the known solutions is reduced. On the basis of a simplified consideration, it can be assumed in this case that the influence of the friction is by a factor R / r, where R is the outer roll radius and r represents the roller bearing radius is reduced. For example, if a roller with an outer radius of 5.4 cm and a roller bearing radius of 1.7 cm used, this results in a factor of 3.8, so a significant reduction in the frictional resistance. By this strong minimization of the influence of friction on the one hand, the release safety of the switching mechanism is increased and on the other hand, the lever ratios in Entklinkungsmechanismus be adjusted so that the reduction of the force from the switching mechanism to the trigger shaft of Entklinkungsmechanismus is very large and thus to trigger the switching mechanism only a very small force is needed.

FIG 1

Perspektivische Darstellung des Schaltschlosses eines Leistungsschalters;

FIG 2 bis 5

Schaltschloss eines Leistungsschalters in EIN-Position in vier verschiedenen Ansichten;

FIG 6

Seitenansicht des Schaltschlosses eines Leistungsschalters während des Auslösevorgangs;

FIG 7 und 8

Seitenansicht des Schaltschlosses eines Leistungsschalters in ausgelöstem Zustand (Trip-Position);

FIG 9 bis 11

Vergleich des aus dem Stand der Technik bekannten Verklinkungsmechanismus mit der erfindungsgemäß ausgeführten Verklinkung in Detailansichten;

FIG 12

Perspektivansicht des Spannhebels mit Rolle; sowie

FIG 13

Perspektivansicht einer Rolle.

In the following the invention without further restriction of the general inventive concept will be explained in more detail by means of embodiments with reference to the figures. Showing:

FIG. 1

Perspective view of the switching mechanism of a circuit breaker;

FIGS. 2 to 5

Switch lock of a circuit breaker in ON position in four different views;

FIG. 6

Side view of the circuit breaker of a circuit breaker during the tripping process;

FIGS. 7 and 8

Side view of the switching mechanism of a circuit breaker in tripped state (trip position);

FIGS. 9 to 11

Comparison of the known from the prior art latching mechanism with the present invention executed latching in detail views;

FIG. 12

Perspective view of the clamping lever with roller; such as

FIG. 13

Perspective view of a roll.

FIG. 1 shows in a perspective view of the switching mechanism 1 of a circuit breaker. The switching mechanism 1 shown here has two main components, namely the switching mechanism 2 on the one hand and the Entklinkungsmechanismus 3 on the other. About the switching mechanism 2 is the electrical switching contact of the circuit breaker in such a way with a spring used as an energy storage 4 in operative connection that when the contact is closed, the spring 4 is tensioned and when the switching mechanism 1, the energy stored in the spring 4 is released, so that the contact is opened by acting on him spring force.

To keep the spring 4 on the one hand reliably in the tensioned state and on the other hand to ensure reliable and rapid release of the switching mechanism, the Entklinkungsmechanismus 3 is provided.

The connection between the switching mechanism 2 with tension spring 4 and the Entklinkungsmechanismus 3 is made via a clamping lever 5, which can be locked or released by the Entklinkungsmechanismus 3 as needed. As soon as the tensioning lever 5 is released by the unlatching mechanism 3, the spring 4 relaxes and the electrical switching contact is opened.

An essential component of Entklinkungsmechanismus 3 is the pawl spring 10, which acts on the pawl 8 so that the end of the pawl 8 is moved against a designated stop surface of the clamping lever 5 for locking the clamping lever 5. Furthermore, in the unlatching mechanism 3, a triggering shaft 9 is provided which, upon reaching a triggering criterion, in particular as soon as the current in the switch reaches a predetermined current, is put into a rotary or pivoting movement. By the movement of the trip shaft 9, this device so in contact with the pawl 8, that also the pawl 8 is pivoted and so the force acting from the end of the pawl 8 on the stop surface of the clamping lever 5 force is reduced. The reduction of the force acting on the stop surface of the clamping lever 5 by the pawl 8 further leads to the fact that the locking of the clamping lever 5 is released, the spring 4 relaxed and the switching contact to be opened. In the following, the various switching states of the switching mechanism 1 will be explained in detail.

In the FIGS. 2 to 5 is the switching mechanism 1, whose components are already in FIG. 1 has been explained in more detail, shown in an on position. The FIGS. 2 and 3 show the switch lock in a side view, the 4 and 5 in a perspective view, wherein the FIG. 3 and 5 show the switch lock each in a cutaway view. In these sectional views, the switching mechanism 1 is divided along the plane of symmetry and in each case only the components provided in the rear part are shown. This way, in the FIG. 3 and 5 the rear side part 14 of the clamping lever 5, the roller 7 mounted thereon and the end 12 of the pawl 8 visible.

In the ON position, the switch is closed, the spring 4 is tensioned and the switch lock 1 is in the locked state.

Furthermore, the Entklinkungsmechanismus 3 and thus also the switching mechanism 1 is in a stretched state, wherein the end 12 of the pawl 8 touches the outer periphery of a rotatably mounted on the clamping lever 5 roller 7 in the region of the stop surface 13. With the help of the pawl 8 of the clamping lever 5 is thus locked in the position shown, so that the spring 4 is tensioned and the electrical switching contact is closed.

FIG. 6 shows a side view of the switching mechanism 1 in an operating state in which this is triggered. The tripping shaft 9 is operated on the basis of a trigger signal, so that the pawl 8 counterclockwise from the Roller 7 is moved away. Then, the force with which the pawl 8 acts on the stop surface 13 of the roller 7 is reduced, the pawl 8 loses contact with the roller 7 and finally slips off the roller 7. By releasing the pawl 8, the tensioning lever 5 finally also performs a pivoting or pivoting movement in the counterclockwise direction, whereby the spring 4 is transferred to a relaxed state and thereby the electrical switching contact is opened.

FIGS. 7 and 8 now show the switching mechanism 1 of a circuit breaker in tripped position. This position of a switching mechanism 1 is also referred to as a trip position. The tensioning lever 5 with the roller 7 rotatably mounted thereon has been transferred to its end position upwards. In this case, he is on a clamping bolt 11 which is mounted in the shift lever 6, on. If the switching mechanism 1 is to be transferred from the trip position back to the on position, with respect to the switching mechanism 1, in particular the Entklinkungsmechanismus 3 a reset must be performed so that the Entklinkungsmechanismus 3 and here in particular the pawl spring 10 tensioned and the trip shaft 9 is reset to its original position.

In the FIGS. 9 to 11 is a known from the prior art latch compared with an inventively executed. To illustrate, first of all, the already in FIG. 3 shown side view of the arranged in the rear part of the switching mechanism 1 components. The invention is characterized in particular by an advantageous design of the clamping lever side provided stop surface 13. In the FIGS. 9 to 11 is a section of the switching mechanism 1 is shown in detail. This show the FIGS. 9 to 11 in each case the lying in the region of the Entklinkungsmechanismus 3 end of the clamping lever 5 with its stop surface 13 and the pawl 8. The hereby in contact FIGS. 9 and 10 show in this context known from the prior art support the Pawl 8 on the stop surface 13 of the clamping lever 5. In comparison, is in FIG. 11 an inventively executed latch, which is realized by the use of a movably arranged curved stop surface 13, which is realized in this case by using the outer peripheral surface of a rotatably mounted on the clamping lever 5 roller 7.

In FIG. 9 is a latch, as known from the prior art, shown in new condition. Between the end 12 of the pawl 8 and the stop surface 13, a flat contact surface is provided in this case. Furthermore, the vector of the release force F _NVar , in the normal direction, that is perpendicular to the stop surface 13, and the lever arm h between the normal vector and a point K, by which the pawl 8 is rotated or pivoted, shown.

In addition to this shows FIG. 10 the well-known support after a certain period of operation. It is essential that a certain wear has occurred due to the friction between the end 12 of the pawl 8 and the stop surface 13 on the stop surface 13 and the clamping lever 8. Due to the abrasion, the contour of the clamping lever 8 is slightly flattened in the region of the stop surface 13 with respect to the initial state. By this friction-related flattening of the contour of the clamping lever, the direction of the normal force F _{Nvarr changes,} which in turn increases the release force of the switching _mechanism 1 relative to the initial state.

The effect described above can hitherto only be reduced by the use of materials of higher hardness of special surface treatment or by the use of lubricants. However, this would increase the costs while at the same time limiting functional reliability and area of application. Another way to reduce abrasion is the full-surface support of the components. However, this technical solution has the disadvantage that the lever arm the normal force and thus the force required to trigger the switching mechanism 1 can vary.

In FIG. 11 is now an embodiment of the invention Verklinkung a switching mechanism 1 shown. In the locked state of Entklinkungsmechanismus 3, the end 12 of the pawl 8 with the outer peripheral surface of a rotatably mounted on the clamping lever 5 roller 7 is engaged. The use of a roller, by which a movable, outwardly curved stop surface 13 is realized, has the particular advantage that the wear on the supporting components is significantly reduced. Furthermore, the angle of the resulting normal force F _{N is held} approximately constant by the support on the roller 7, so that the release force range is relatively small and does not increase with increasing life of the components. Due to the resulting minimization of the influence of friction on the one hand, the release safety of the pawl 8 is increased and on the other hand, the lever ratios in Entklinkungsmechanismus 3 can be adjusted so that the reduction of the power of switching mechanism 2 to trip shaft 9 is very large and thus to trigger the switch latch 1 only one comparatively low power is needed.

FIG. 12 shows in a perspective detail view of an inventively designed clamping lever 5, which creates a connection between the spring element 4 of the switching mechanism 2 and the Entklinkungsmechanismus 3. Here, the tensioning lever 5 is designed substantially in two parts and has two plane-parallel clamping lever, in particular, this is 2 identical components, between which further components are arranged. In the region of the clamping lever 5, which faces in the installed position the Entklinkungsmechanismus 3, a roller 7 is provided which is rotatably supported in the clamping lever 5 via two bearing pins 16.

In addition is in FIG. 13 the role 7 shown. The roller 7 designed as a rotating part has an outer circumferential surface, which is used as a stop surface 13 for the pawl 8. With regard to the execution of the roller 7, it can be simplified to illustrate that the influence of the friction is reduced by the factor R / r, where R represents the roller outer radius and the roller bearing radius. With an outer radius of the roller of R = 5.4 cm and a roller bearing radius of r = 1.7 cm, this results in a factor of 3.18, which corresponds to a reduction of friction by more than three times.

By providing a roller 7 whose outer peripheral surface forms the abutment surface 13 for the pawl 8 of the unlatching mechanism 3, in particular the release safety of the pawl and a minimization and a limitation of the range of the release force can be achieved in a relatively simple manner.

Claims (8)

Circuit breaker comprising a switching mechanism (1) having a switching mechanism (2) for opening and closing a switching contact operatively connected to a tensioning element (4), and a unlatching mechanism (3) for actuating the tensioning element (4) on the basis of a triggering signal in such a way from a tensioned in an at least largely untensioned state can be converted, that the switching contact is thereby opened, wherein the clamping element (4) is coupled to a clamping lever (5), which has a stop surface (13) on which in the tensioned state of Clamping element (4) bears a pawl (8) of the Entklinkungsmechanismus (3),
characterized in that the stop surface (13) in the direction of the pawl (8) is curved and is arranged to be movable relative to the clamping lever (5). Circuit breaker according to Claim 1,
characterized in that the abutment surface (13) is disposed on an outer peripheral surface of a roller (7). Circuit breaker according to claim 2,
characterized in that the roller (7) is designed as a sheet metal component. Circuit breaker according to one of claims 1 to 3,
characterized in that the stop surface (13) comprises a plastic. Circuit breaker according to Claim 2 or 3,
characterized in that the roller (7) comprises a plastic. Circuit breaker according to one of Claims 1 to 5,
characterized in that the tensioning lever (5) has two side parts (14, 15), between which a roller (7), on the stop surface (13) is arranged, is rotatably mounted. Circuit breaker according to one of Claims 1 to 5,
characterized in that the clamping lever (5) is designed in one piece and has a recess, within which a roller (7) is provided with stop surface. Circuit breaker according to one of claims 1 to 7,
characterized in that the roller (7) by means of a bearing pin or two bearing pins (16) is mounted on the clamping lever (8) and a quotient of roller radius and bearing pin radius assumes a value> 1.0.

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