The present invention belongs to electricity, particularly to basic electric elements, namely to electric switches and details of protective switches, which are actuated by means of a combination of an electro-thermal and magnetic mechanism and controlled by means of appropriate lever. On the other hand, such invention can also belong to physics, namely to measuring of electric variables.

The purpose of the invention is to create a device for protecting electric circuits against electric overloading, which would be able to indicate each reason for interruption, so that it should be visible from outside, if each interruption of the electric circuit was initiated by overloading of the electric circuit, in particular excessive current.

A device for protection of an electric circuit against electric overloading as such is disclosed in an earlier application EP 2 545 576 Bl of the same applicant, to which the applicant refers by reference. Before that, a bipolar electric switch has been disclosed in EP 1 488 438 Al, which comprises a fixed contact member as well as a further pivotally movable contact member, which is biased by means of a spring and such maintained in its connected position, as well as an actuating unit, which via an actuating lever affects said movable contact member, and moreover a corresponding trigger with a needle, which in the case of irregularities affects said actuating lever by releasing an engaging clasp, by which then each electric circuit with integrated switch is interrupted.

The present invention refers to a device for protecting electric circuits against electric overloading, said device comprising

- an actuating unit, which consists of an electric insulating material and is within a casing, which also consists of an electric insulating material, pivotally embedded in a pivot point and comprises an actuating handle, which protrudes outside from said casing;

- an engaging clasp, which is pivotally attached to said actuating unit, and is adapted for supporting said actuating unit and resting on a disconnecting lever;

- a disconnecting lever, which is within said casing pivotally embedded in a pivot point and supported by a spring, which is adapted for pressing said disconnecting lever towards the actuating unit, wherein said disconnecting lever is on the one hand furnished with an arm, which is adapted for resting on a movable contact member, and is on the other hand pivotally connected with an actuating lever in a pivot joint;

- a movable contact member, which is embedded within said casing in a pivot point and supported with a spring, which is adapted for pressing the movable the last in a direction apart from the fixed contact member and opposite to the force of said spring, and wherein said movable contact member and said fixed contact member each per se consist of electric conducting material and are each per se via corresponding connectors on the casing connectable into each electric circuit, which is established, when said contact members are in contact with each other, and interrupted when they are spaced apart from each other;

- a trigger, which includes a needle, a bimetallic washer connected thereto, as well as a coil, which is similarly like the previously mentioned contact members connectable into each electric circuit and adapted to cooperate with a magnet, which is also connected with said needle; and

- an actuating lever, which comprises an arm, which is located in front of said needle of the trigger, wherein the opposite arm of the actuating lever is adapted to cooperate with the engaging clasp, and wherein between said first arm and the actuating unit a tension spring is tensioned.

The invention proposes that such device further comprises two sensors, which are integrated within said casing and are suitable for measuring of velocity, wherein the first sensor is located adjacent to the actuating lever and is adapted to cooperate with a protrusion on the actuating lever for the purpose of measuring of the velocity of the actuating lever when being displaced, while the second sensor is located adjacent to the actuating unit and is adapted to cooperate with a protrusion on the actuating unit for the purpose of measuring of the velocity of the actuating unit when being pivoted around the pivot point. Said sensors are connected with a control unit, which is on the other hand connected with at least two indicators, which are located on the casing and are visible from outside, wherein said control In this, at least one of said indicators is adapted to signalize manual interruption of the electric circuit, when the velocity of the actuating lever is lower than the velocity of the actuating unit. On the other hand, at least one of said indicators is adapted to signalize interruption of the electric circuit due to electric overloading thereof, wherein the velocity of the actuating lever is higher than the velocity of the actuating unit. Optionally, at least one indicator is foreseen, which is activated when the electric circuit is established and operates regularly i.e. without any overloading. Each of said indicators is generally suitable for indicating its active or inactive state, wherein in a preferred embodiment of the invention at least one of said indicators is available as a light emitting diode (LED).

The invention will be described in more detail on the basis of an embodiment, which is presented in the attached drawings, wherein

Fig. 1 is a schematically presented device according to the invention, when switched-on during a regular operation of the electric circuit;

Fig. 2 is a schematically presented device according to the invention, when manually switched-off;

Fig. 3 is a schematically presented device according to the invention, when switched-off due to electric overloading; and

Fig. 4 is a schematic presentation of arrangement of sensors with corresponding control unit and indicators.

A device for protecting electric circuits against electric overloading comprises an actuating unit 1, which consists of an electric insulating material and is within a not-shown casing, which also consists of an electric insulating material, pivotally An engaging clasp 2 is pivotally attached to said actuating unit 1 , and is during the regular functioning intended for supporting said actuating unit 1 and on the other hand adapted for resting on a disconnecting lever 4, which is in said casing pivotally embedded in a pivot point 40 and supported by a spring 41 , which is intended for pressing said disconnecting lever 4 towards the actuating unit 1. Said disconnecting lever 4 is on the one hand furnished with an arm 42, which is adapted for resting on a movable contact member 71, and is on the other hand connected with an actuating lever 3 in a pivot joint 43 pivotally.

Said movable contact member 71 is embedded within the casing in a pivot point 71 ' and supported with a spring 71 ", which is intended for pressing the movable contact member 71 towards the fixed contact member 72. Said arm 42 of the disconnecting lever 4 is adapted to rest on the movable contact member 71 and to press the last in a direction apart from the fixed contact member 72 and opposite to the force of said spring 71 ". Said movable contact member 71 and said fixed contact member 72 are each per se made of electric conducting material and are each per se via not-shown connectors on the casing connectable into each electric circuit, which is established, when said contact members 71, 72 are in contact with each other, and interrupted when they are spaced apart from each other.

Moreover, said device comprises a trigger 5, which includes a needle 51, with which a bimetallic washer 52 is connected, as well as a coil 53, which is similarly like the previously mentioned contact members 71, 72 connectable into each electric circuit and adapted to cooperate with a not-shown magnet, which is also connected with said needle 51. The needle is movable in its axial direction towards When heat is generated due to excessive current, the needle 51 is axially displaced by means of said bimetallic washer 52, and when the differential current occurs a magnet force is generated within the coil 53, which results in displacement of the needle 51 towards the actuating lever 3.

The actuating lever 3 comprises an arm 31 , which is located in front of the needle 51 and between which and the actuating unit 1 a tension spring 32 is tensioned. The opposite arm 33 of the actuating lever 3 is adapted to cooperate with the engaging clasp 2.

Moreover, two sensors 81, 82 are integrated within said casing, which are suitable for measuring of velocity, wherein the first sensor 81 is located adjacent to the actuating lever 3 and is adapted to cooperate with a protrusion 32 on the actuating lever 3 for the purpose of measuring of the velocity V _v by displacing the actuating lever 3, while the second sensor 82 is located adjacent to the actuating unit 1 and is adapted to cooperate with a protrusion 12 on the actuating unit 1 for the purpose of measuring of the velocity V _g by pivoting the actuating unit 1 around the pivot point 10.

Said sensors 81, 82 are connected with a control unit 9, which is on the other hand connected with at least two indicators 91, 92, 93, which are located on the casing and are visible from outside.

Each of said indicators 91, 92, 93 is suitable for indicating its active or inactive state and is e.g. available as a light emitting diode (LED), by which the control unit The first indicator 91 is adapted to signalize manual interruption (Fig. 2), in which the following condition is fulfilled:

V _v < V _g .

When the device is manually switched-off in order to interrupt each electric circuit, in which it is integrated, then the circumferential velocity V _g of pivoting the actuating unit 1 is higher than the velocity V _v of displacing the actuating member 3.

The first indicator 92 is adapted to signalize interruption due to overloading of the electric circuit (Fig. 3), in which the following condition is fulfilled:

V _v > V _g .

When each disposable electric circuit, into which the device is integrated, is interrupted due to overloading, then the needle 51 abuts the actuating member 3, the velocity V _v of which is higher than the circumferential velocity V _g of the actuating unit 1. Namely, when the needle 51 abuts the arm 31 of the actuating member 3, the last starts moving immediately and passes the corresponding sensor 81 with a relatively high velocity V _v , by which the engaging clasp 2 is displaced, by means of which in its initial position according to Fig. 1 the actuating unit 1 was supported, and upon that the actuating unit 1 is pivoted thanks to the force of the spring 32 with a circumferential velocity V _g relatively to the belonging sensor 82.

A still further indicator is optionally foreseen, which indicates that the electric