DE102008020925B4 - Overcurrent protective device for closing or interrupting a current flow in the event of an overload, as well as methods for interrupting a current flow in the event of an overload - Google Patents

Abstract

Overcurrent protection device, comprising a switch lock for closing or interrupting the flow of current, a release lever (1) for actuating the switch lock, a bimetal element (2) that can be bent by heating and a tension bracket (3) that can be moved through the bimetal element (2), the release lever (1) is not moved by the bimetal element (2), the tension bracket (3) being able to be acted upon by a first energy store (4) with a first force when it moves through the bimetal element (2), the first force opposing the movement of the tension bracket (3 ) acts through the bimetal element (2), and wherein the overcurrent protection device has a second energy storage device (5), via which the tension bracket (3) can be acted upon with a second force, around the tension bracket (3) against the first force of the first energy storage device (4 ) and thus actuate the release lever (1).

Description

The present invention relates to an overcurrent protection device, comprising a switching mechanism for closing or interrupting a current flow, a release lever for actuating the switching mechanism, a bimetallic element which can be bent by heating, and a drawbar which can be moved by the bimetallic element and which is moved by the bimetallic element through a first energy store the first force can be acted upon, wherein the first force acts against the movement of the drawbar by the bimetallic element. Furthermore, the invention relates to a method for actuating a release lever of a switching mechanism of an overcurrent protection device for interrupting a current flow in case of overload or short circuit.

Overcurrent protective devices are electrical switching devices that interrupt a current flow when the current exceeds a predetermined current for a certain period of time. In other words, overcurrent protection devices must open the current path after a certain time in case of overload or short-circuit and interrupt the current flow. Overcurrent protection devices thereby protect cables, loads or consumers connected to the overcurrent protection devices from damage due to overheating, which would result from the overcurrent flowing over a relatively long period of time. An overcurrent can be caused by an overload or a short circuit.

An overcurrent protection device can react differently depending on requirements. That is, the reaction time for triggering the overcurrent protection device is dependent on the current levels occurring. In the event of an overload, the circuit is interrupted delayed. The tripping time is within seconds, but may also be less overloaded in the hourly range. On the other hand, in the event of a short circuit, where a current of several thousand amperes can flow, the flow of current must be interrupted within a few thousandths of a second.

Typical overcurrent protection devices are circuit breakers or circuit breakers. Overcurrent protection devices are generally used in electrical installations.

Overcurrent protective devices, such as circuit breakers or circuit breakers, must unlatch a switch lock in case of overload to open the current path. For this purpose, usually a bimetallic element of the overcurrent protection device is heated by the current flow. When heated, the bimetal element bends and its movement is transmitted to a trigger lever. After appropriate movement of the release lever releases the latch and the switch lock goes into the off position. The bimetallic element works in this case against the so-called Entklinkungskraft the release lever.

Such overcurrent protection device is for example from the DE 21 44 495 A known. The release lever of the overcurrent protection device is triggered by the bimetal release. After triggering of the release lever by the movement of the bimetallic release is additionally ensured by a shared lever that the contacts of the overcurrent protection device are actually disconnected. A disadvantage of such an overcurrent protection device is that when a change in the bimetallic no gleichmaßige release of the release lever can be guaranteed. The lever will not function until after the pressure switch of the overcurrent protection device has been released by the bimetallic release.

Object of the present invention is to provide an overcurrent protection device and a method for interrupting a current flow in an overload case, which allow a particularly secure interruption of the current flow. In particular, the operation of a Auslosehebels a switching mechanism of the overcurrent protection device should be made safer and more constant. That is, the thermal release should scatter less and be more constant.

This object is achieved by an overcurrent protection device with the features according to independent claim 1 and by a method for actuating a trigger lever of a switching mechanism of an overcurrent protection device for interrupting a current flow in a Uberlastfall with the features according to the independent claim 7. Further features and details of the invention will become apparent from the dependent claims, the description and the drawings. Features and details that are described in connection with the overcurrent protection device of course also apply in connection with the process, and vice versa.

According to the first aspect of the invention, the object is achieved by an overcurrent protection device, comprising a switching mechanism for closing or interrupting a current flow, a release lever for actuating the switching mechanism, a bimetallic element which can be bent by heating, and a drawbar which can be moved by the bimetallic element can be acted upon by a first energy storage with a first force, wherein the first force acts against the movement of the drawbar by the bimetallic element, and in which the overcurrent protection device has a second energy storage, via which the clamping yoke can be acted upon by a second force to move the clamping yoke against the first force of the first energy storage and thus to actuate the trigger lever, solved.

The core of the invention is that the overcurrent protection device has a second energy storage, via which the Zugbugel can be acted upon by a second force to move the clamping yoke against the first force of the first energy storage and thus to actuate the release lever. As a result, the actuation of the release lever can be independent of the force of the bimetallic element. D. h., That bimetallic element is indeed the impetus to actuate the release lever, but exerts itself no force on the release lever to effect the unlatching of the switch lock.

An energy store according to the invention represents a device which can exert a force on the clamping yoke of the overcurrent protection device. In this case, the respective energy store can be attached directly to the clamping yoke to move it. But it is also conceivable that an energy storage is not directly connected to the clamping yoke to move it. In the further embodiments, various energy stores are described by way of example.

The overcurrent protection device has a switching mechanism for closing or interrupting a current flow. The switch lock can be actuated by the release lever. Furthermore, the overcurrent protection device has a bimetal element, which can be bent by heating due to an increased current flow. D. h., The bimetallic element is arranged in the overcurrent protection device that this moves at a distortion due to heating the drawbar. During a movement of the drawbar this is moved by the bimetal against a force of a first energy storage. D. h., The force of the first energy storage counteracts the force that is exerted by the bimetallic element on the Zugbugel. The bimetallic element moves the yoke only up to a certain point against the defined force of the first energy storage. The release lever is not moved by the bimetal and thus the bimetal does not have to do the so-called Entklinkungsarbeit for actuating the Auslosehebels. At a certain point another, second energy storage takes over the movement of the drawbar and thus also the operation of the release lever, which in turn allows the unlatching of the switching mechanism.

The first energy storage on the one hand has the function of holding the drawbar in an initial position, so that it is not movable without the force of the bimetal element. On the other hand, the power of the first energy storage ensures that the clamping yoke is moved back to a release latch of the switching mechanism to its original position, so as to allow further latching of the switching mechanism.

The second energy storage does not attack by itself on the clamping yoke to move it, but only after the bimetallic a certain predetermined deflection, d. H. Displacement and / or pivoting, has performed the drawbar. When the clamping yoke reaches the predetermined position, the second energy store exerts a force on the clamping yoke, which counteracts the first force of the first energy store. By the force of the second energy storage of the drawbar is further moved in the direction in which the bimetallic element has already moved the drawbar. In this case, the second energy storage initially supports the movement of the Zugbugels by the bimetallic element until it is solely responsible for its movement from a certain position of the drawbar to actuate the release lever of the switching mechanism.

As a result, the bimetallic element does not additionally overcome the Entklinkungskraft that is required for the operation of the release lever. This takes over the second energy storage from a certain time or a specific position of Zugbugels. The advantage of such a trained overcurrent protection device is the most secure interruption of the current flow in the event of an overload. In particular, the operation of the release lever of the switching mechanism of the overcurrent protection device can be made safer and more constant. The thermal release scatters less and is more constant.

From a certain deflection of the drawbar, the second force of the second energy storage exceeds the first force of the first energy storage. The clamping yoke is thereby moved further in the direction of movement through the bimetallic element and only by the induced by the second energy storage movement of the trigger lever is actuated and unlatches the switching mechanism.

The unlatching of the switching mechanism is thus not so much dependent on the curvature of the bimetallic element. This gives only the impetus for unlatching the switch lock. The force for unlatching, d. H. for actuating the release lever, takes over the second energy storage.

The energy storage of the overcurrent protection device can be designed in various ways. Particularly preferred is an overcurrent protection device in which the first energy store is a resilient element and in which the second energy store is a permanent magnet. The bimetal moves the yoke only up to a certain point against the spring force of the first energy storage, such as a Zugbügelfeder.

The release lever is not moved by the bimetallic element and thus the bimetallic element does not have to perform the unlatching work. From a certain point, d. H. a certain position of the drawbar, takes over the second energy storage, preferably designed as a permanent magnet, the movement of the drawbar to the actuation of the Auslosehebels. The clamping yoke is at least partially ferromagnetic. The permanent magnet moves in case of overload, the clamping yoke against the force of the resilient element, in particular the Zugbügelfeder. From a certain deflection, the attractive force of the permanent magnet exceeds the restoring force of the resilient element. The clamping yoke is attracted to the permanent magnet and only by the movement induced by the permanent magnet movement of the trigger is then actuated and unlocks the switch lock. D. h., The drawbar actuated solely by the force of attraction of the permanent magnet, the release lever, so that the switch lock is unlatched.

In the switched-off state, the second energy store, in particular in the form of a permanent magnet, is moved away into its off position by the switching mechanism, so that the clamping yoke is moved away from the first energy store, i. H. the spring-elastic element, can be moved back to its original position and thus allows further latching of the switch lock. When switching on the permanent magnet is then moved back to its on position.

The resilient element may be formed depending on the position of the clamping yoke as a pressure or tension element. Preferably, the resilient element of the overcurrent protection device is arranged between the yoke and the second energy storage. Here, the elastic element is designed as a pressure element, in particular as a compression spring. The spring-elastic element can furthermore be arranged directly on the second energy store, in particular if it is designed in the form of a permanent magnet.

Preferably, the clamping yoke of the overcurrent protection device is kept pivotable and / or displaceable. In general, the clamping yoke is slidably mounted within the overcurrent protection device.

The overcurrent protection device is advantageously designed as a circuit breaker or a circuit breaker. The overcurrent protection device may have, in addition to the overload or short-circuit functionality, a device for protection against a fault current.

• – ein durch Erwärmung krümmbares Bimetallelement der Überstromschutzeinrichtung wird bei einem Überstrom erwarmt und dadurch verkrümmt;
• – aufgrund der Verkrümmung bewegt das Bimetallelement einen bewegbaren Zugbügel der Überstromschutzeinrichtung entgegen einer ersten Kraft eines ersten Energiespeichers der Uberstromschutzeinrichtung;
• – nach einer bestimmten vorgebbaren Verschiebung des Zugbügels durch das Bimetallelement ubt ein zweiter Energiespeicher der Überstromschutzeinrichtung eine zweite Kraft auf den Zugbügel aus, wobei die zweite Kraft entgegen der ersten Kraft des ersten Energiespeichers wirkt, so dass der Zugbügel weiter entgegen der Richtung der ersten Kraft bewegt wird,
• – nach einer bestimmten weiteren Verschiebung des Zugbügels durch die Kraft des zweiten Energiespeichers betätigt der Zugbügel den Auslösehebel, so dass dieser das Schaltschloss zur Unterbrechung des Stromflusses öffnet.

According to the second aspect of the invention, the object is achieved by a method for actuating a tripping lever of a switch lock of an overcurrent protection device for interrupting a current flow in the event of an overload, the method being characterized by the following step:

• - A bimetallic element of the overcurrent protection device which can be bent by heating is heated in an overcurrent and thereby bent;
• - Due to the distortion, the bimetal moves a movable clamping yoke of the overcurrent protection device against a first force of a first energy storage of the overcurrent protection device;
• After a certain predeterminable displacement of the drawbar by the bimetallic element, a second energy storage of the overcurrent protection device exhausts a second force on the drawbar, the second force counteracting the first force of the first energy storage, so that the drawbar continues to move counter to the direction of the first force becomes,
• - After a certain further displacement of the drawbar by the force of the second energy storage of the clamping lever actuates the release lever so that it opens the switch lock to interrupt the flow of current.

The core of the method is that after a certain predetermined displacement of the drawbar by the bimetallic element, a second energy storage of the overcurrent protection device exerts a second force on the drawbar. This second force takes over the deflection of the drawbar in the direction in which the drawbar has already been moved by the force of the bimetallic element.

As a result, the bimetallic element does not have to expend so much force, since it only has to move the drawbar to the position at which the second energy store assumes the movement of the tensile bow. As a result, even weak bimetallic elements can still apply a sufficiently large force to initialize the release of the latch. In this method, the bimetallic element does not have to apply any force for actuating the release lever, since this is taken over by the second energy store, in particular in the form of a permanent magnet. The second force of the second Energy storage, in particular of the permanent magnet, counteracts the first force of the first energy storage, so that the drawbar can be further moved against the direction of the first force. The bimetallic element which warps due to heating gives rise to the movement of the drawbar and thus to the actuation of the release lever or the interruption of the flow of current through the switching mechanism.

A method is preferred in which the overcurrent protection device according to the first aspect of the invention is designed to carry out the method.

Preferably, the bimetallic element moves the movable clamping yoke against a spring force of a spring-elastic element, in particular a Zugbügelfeder, the overcurrent protection device After the specific predetermined displacement of the drawbar by the bimetallic element, a permanent magnet of the overcurrent protection device exerts the second force on the clamping yoke. Due to the force of the permanent magnet, the clamping yoke is guided against the release lever in order to actuate it.

The length of the displacement of the drawbar, from which the second energy storage exerts a force on the clamping yoke, can be variably determined via an input unit of the overcurrent protection device. As a result, the overcurrent protection device can be set to changed conditions. In particular, a fluctuation in the curvature of the bimetallic element can be bleached thereby.

The particular advantage of the above-described overcurrent protection device or the previously described method is that not the bimetal must solve the latch. This has the particular advantage that weak bimetals move the Zugbugel only against a defined spring force of Zugbügelfeder and do not have to work against the sometimes quite high Verklinkungskraft the Verklinkungsfeder. The thermal release no longer depends on the latching force, which can change over time. Thus, thermal tripping will be less scattered and more consistent.

The invention will now be explained in more detail with reference to a non-exclusive embodiment, with reference to the accompanying drawings. Show it:

1 - 4 schematically the movement of the drawbar of an overcurrent protection device.

In the 1 to 4 is each a trigger 1 , a bimetallic element 2 , a drawbar 3 and a first and a second energy storage 4 . 5 an overcurrent protection device shown.

In 1 is still no operation of the release lever 1 through the drawbar 3 he follows. The bimetal element 2 moves or warps when heated in the direction of the projection 7 of the drawbar 3 , This movement or curvature is indicated by the arrow.

Reaching the bimetal element 2 the lead 7 of the drawbar 3 moves the bimetallic element 2 the drawbar 3 in the direction of the first energy store 4 , which in this embodiment represents a tension bow spring. This drawbar spring 4 exerts a first force on the drawbar 3 off, the movement of the drawbar 3 through the bimetallic element 2 counteracts. The drawbar spring 4 is through the drawbar 3 or that of the bimetallic element 2 on the drawbar 3 applied force compressed, see 2 , In the in 2 shown position has the bimetallic element 2 the drawbar 3 deflected so far that this from the second energy storage 5 , here in the form of a permanent magnet, attracted and solely by the permanent magnet 5 is moved against the Zugbugelfederkraft. Part of the Zugbugelfeder 4 is for fixing the Zugbügelfeder 4 on a stationary wall element 6 the overcurrent protection device attached. In this case, the magnetic field of the permanent magnet 5 through the wall of the wall element 6 on the drawbar 3 Act. Advantageously, the wall element 6 However, a recess on which the permanent magnet 5 is arranged in alignment. This is at least partially no element between the yoke 3 and the permanent magnet 5 arranged so that the magnetic force undisturbed on the drawbar 3 can work.

The train ball 3 actuated solely by the attraction of the permanent magnet 5 the tripping lever 1 so that the switch lock is unlatched. This is in 3 shown. The power of the second energy store 5 is greater than the power of the first energy store 4 , so that the Zugbugel further in the direction of the second energy storage 5 is shifted, thereby the release lever 1 to operate and accordingly the switch lock to interrupt the flow of current unlatched.

In the off state, the permanent magnet 5 moved away by the switch lock in its off position, which is indicated by the arrow in 4 is hinted, so that the drawbar 3 from the drawbar spring 4 can be moved back to its original position and a further latching of the switch lock is possible. When switched on, the permanent magnet 5 then moved back to its on position.

The bimetal element 2 moves the drawbar 3 only up to a certain point against the defined force of the Zugbügelfeder 4 , The release lever 1 is through the bimetallic element 2 not moved and thus makes the bimetallic element 2 not even the unlatching work. At a certain point, the permanent magnet takes over 5 the movement of the release lever 1 and thus the operation of the tripping lever 1 and the unlatching of the switch lock.

The bimetal element 2 moved in case of overload the at least partially ferromagnetic clamping yoke 3 against the defined force of the drawbar spring 4 , From a certain displacement or a certain deflection exceeds the attraction of the permanent magnet 5 the restoring force of the tension bow spring 4 , The release lever 1 is then only by the permanent magnet 5 induced movement of the drawbar 3 pressed and unlocks the switch lock.

By an overcurrent protection device with such components does not need the bimetallic element 2 release the latch of the switch lock. This has the particular advantage that weak bimetallic elements 2 the drawbar 3 only against a defined spring force of the Zugbügelfeder 4 and do not have to work against the sometimes quite high latching power and the latching spring.

LIST OF REFERENCE NUMBERS

1

Release lever of the switch lock

2

bimetallic

3

Bail

4

first energy store

5

second energy store

6

Wall element of the overcurrent protection device

7

Projection of the drawbar

Claims (9)

Overcurrent protection device, comprising a switching mechanism for closing or interrupting a current flow, a release lever ( 1 ) for actuating the switching mechanism, a bimetal element which can be bent by heating ( 2 ) as well as a through the bimetallic element ( 2 ) movable clamping yoke ( 3 ), whereby the release lever ( 1 ) by the bimetallic element ( 2 ) is not moved, wherein the drawbar ( 3 ) during a movement through the bimetallic element ( 2 ) by a first energy store ( 4 ) can be acted upon with a first force, wherein the first force against the movement of the drawbar ( 3 ) by the bimetallic element ( 2 ), and wherein the overcurrent protection device a second energy storage ( 5 ), over which the drawbar ( 3 ) is acted upon by a second force to the drawbar ( 3 ) against the first force of the first energy store ( 4 ) and thus the release lever ( 1 ). Overcurrent protection device according to claim 1, characterized in that the first energy store ( 4 ) a resilient element and that the second energy storage ( 5 ) is a permanent magnet. Overcurrent protection device according to claim 2, characterized in that the spring-elastic element ( 4 ) between the drawbar ( 3 ) and the second energy store ( 5 ) is arranged. Overcurrent protection device according to one of Claims 2 to 3, characterized in that the spring-elastic element ( 4 ) is a tension bow spring. Overcurrent protection device according to one of claims 1 to 4, characterized in that the drawbar ( 3 ) is held pivotable and / or displaceable. Overcurrent protection device according to one of claims 1 to 5, characterized in that the overcurrent protection device is a circuit breaker or a circuit breaker. Method for actuating a trigger lever ( 1 ) of a switching mechanism of an overcurrent protection device for interrupting a current flow in the event of an overload, characterized by the following steps: - a bimetallic element which can be bent by heating ( 2 ) of the overcurrent protection device is heated in an overcurrent and thereby curved; Due to the distortion, the bimetallic element ( 2 ) a movable drawbar ( 3 ) of the overcurrent protection device against a first force of a first energy store ( 4 ) of the overcurrent protection device, wherein the release lever ( 1 ) by the bimetallic element ( 2 ) is not moved; - after a certain predeterminable displacement of the drawbar ( 3 ) by the bimetallic element ( 2 ) exercises a second energy store ( 5 ) of the overcurrent protection device a second force on the clamping yoke ( 3 ), wherein the second force counter to the first force of the first energy store ( 4 ) acts, so that the drawbar ( 3 ) is moved further counter to the direction of the first force, - after a certain further displacement of the drawbar ( 3 ) by the force of the second energy store ( 5 ) the clamping yoke ( 3 ) the release lever ( 1 ), so that this opens the switch lock to interrupt the flow of current. A method according to claim 7, characterized in that for carrying out the method, the overcurrent protection device is designed according to one of claims 1 to 6. A method according to claim 7, characterized in that for carrying out the method, the overcurrent protection device is designed according to one of claims 2 to 6 and that the length of the displacement of the drawbar ( 3 ), from which the permanent magnet ( 5 ) a force on the clamping yoke ( 3 ), is variably determinable via an input unit of the overcurrent protection device.

Images