The invention belongs to electricity, namely to basic electric components, in particular to switches and details of protective electric switches, which are actuated by means of appropriate handle.

The purpose of the invention is to create such protective electric switch, which should upon integration thereof into each desired electric circuit interrupt such circuit either in the case of thermal overloading or also in the case, when a short circuit current would occur, wherein in particular in the presence of short circuit current interruption of the circuit should be executed essentially quicker and more reliable as by currently known switches.

An electric switch is described in EP 1 488 438 Bl, which comprises a contacting assembly consisting of a fixed contact as well as a pivotally movable contact, which is tensioned by means of a spring and maintained in its connected position, and moreover of an actuating handle, which is via a pivotable actuating lever allowed to impact said movable contact, as well as of a trigger, which is furnished with a needle and which impacts said actuating lever by releasing an engaging clasp as soon as an irregularity is detected within the circuit. In such switch, the first and the second contact assembly, each comprising one movable and one fixed contact, are pivotally around the same axis embedded on the housing an d are by means of a spring maintained in the connecting position. Moreover, an actuating handle is pivotally embedded on said housing and is by means of said spring of a movable contact allowed to be shifted into an interrupting position, in which the movable contact are maintained in disengaged i.e. deactivated position. The actuating lever is via the engaging clasp interconnected with the actuating handle, so that the actuating handle is then allowed to be pivoted against the force of the said spring from the interrupting into the connecting position, in which it then remains until the actuating lever is connected with the actuating handle.

In such switch, said trigger comprises a coil and a bimetallic washer, and moreover also a needle, which is allowed to be ejected towards the pivotable actuating lever, or the disconnecting lever respectively, by means of said bimetallic washer or by means of said coil. Whenever the electric circuit is thermally overloaded, the needle is ejected along its longitudinal axis by means of the bimetallic washer towards the pivotable actuating lever, by which the disconnecting lever is released and is then rotated around its pivot axis by means of spring, by which the movable contact is displaced apart from the fixed contact, by which the circuit is interrupted, while by rotating said disconnecting lever also the actuating handle, which is via the engaging clasp connected thereto, is simultaneously rotated. As soon as the reason for said thermal overloading of the electric circuit is then removed, the actuating handle can be pivoted in the opposite direction, by which also the disconnecting lever is pivoted in the opposite direction with respect to the previously mentioned one, by which the movable contact is rest onto the fixed contact and the disconnecting lever is brought into such position, where the actuating lever can be arrested thereon, upon which the disconnecting lever is thanks to the spring no more allowed to be pivoted in the opposite direction and the movable contact is maintained in its resting position on the fixed contact. As soon as a short circuit current appears suddenly in such circuit, appropriate magnetic field is generated within said coil, by which the needle is promptly ejected in a direction towards the actuating lever, which takes essentially less time than e.g. heating the bimetallic washer up to its activation temperature. Due to impact into said actuating lever, the last is displaced, upon which the disconnecting lever starts pivoting due to the spring, by which on the one hand also the actuating handle is pivoted and on the other hand the movable contact is displaced apart from the fixed contact. By considering the need on really prompt interruption of each circuit, when said short circuit current occurs, the time period, during which all these steps are performed, is still much too long. In order to assure a sufficient distance between said contacts, an additional protrusion is foreseen on the disconnecting lever, which is then abutted by the needle upon displacement of the actuating lever, by which a desired pivoting of the actuating lever should be accelerated due to a kinetic energy. Despite to such measure the practical experience shows that displacing of the movable contact apart from the fixed contact is still performed much too slow, and that damages due to appearance of said short circuit current, including generation of arc between said contacts, could be completely avoided. As soon as the needle of the trigger hits said protrusion on the actuating lever, due to such concept of arrangement of the spring between the pivot point of the actuating lever and the trigger, in the early stage the spring is even hindering the actuating lever from being pivoted, which on the one hand results in a time consumption by displacing the movable contact apart from the fixed contact, and on the other hand in possible vibrations of the movable contact with respect to the fixed contact. Consequently, the arc may be generated between the movable contact and the fixed contact, which makes interruption of the electric circuit in the area between said contacts difficult or even quite impossible. The invention relates to a protective electric switch, in which a casing consisting of electric insulating material is furnished with at least two electric contacts for attaching at least two wires, by means of which the switch can be integrated into each desired electric circuit, while inside of said casing a movable contact and a fixed contact are foreseen for the purposes of interconnecting or interrupting said electric circuit, which each per se consist of electric conductive material and are each per se connected to said contacts used for integration into each electric circuit. Said movable contact is adapted to cooperate with a disconnecting mechanism, which is joined with an actuating handle adapted for controlling the switch and indicating errors, and can be activated by means of a trigger, which comprises at least an electric coil, a bimetallic washer and a needle, which may impact said disconnecting mechanism either due to thermal dilatation of said bimetallic washer or due to magnetic field generated by said coil. Said actuating handle is pivotally embedded within the casing and comprises an outside from the casing protruding portion and an inside of the casing located portion, to which an engaging clasp is attached, which serves for connecting the handle with said disconnecting mechanism, Said disconnecting mechanism comprises a disconnecting lever and an actuating lever. The disconnecting lever is in its pivot point pivotally embedded within the casing and comprises a second seat, which is located adjacent to the needle of the trigger, and a first seat, which is located adjacent to the actuating handle and adapted to cooperate with the engaging clasp, and moreover also a tooth, which is located between said seats and to which a tension spring is attached, which is on the other hand attached to the movable contact. On the other hand, the actuating lever is pivotally embedded in its pivot point on the disconnecting lever, comprises a first arm, which is located just in front of the needle of the trigger, and a second arm, which is located opposite with respect to said pivot point and adjacent to said seat of the disconnecting lever, so that the engaging clasp, which is on the one hand linked to the actuating handle, is insertable between the second arm of the actuating lever and the seat of the disconnecting lever.

The invention provides that the movable contact is conceived as an uniform lever, which is pivotally around its pivot point embedded within the casing and is allowed to be pivoted from its first stable position, in which it is rest onto the fixed contact, into its second stable position at certain distance apart from said fixed contact, and which is adapted to cooperate with the disconnecting mechanism, namely either with the disconnecting lever or with the actuating lever thereof. In this, said movable contact is adapted to be pressed towards the fixed contact by means of the spring, which is preferably a tension helical spring and is tensioned between the tooth on the disconnecting lever and the seat, which is located on the movable contact apart from the pivot point and at an appropriate angle with respect to a direction, in which said arm is extending, and wherein said arm of the movable contact is furnished with a resting surface, which is intended for cooperation either with a seat of the disconnecting lever, which is located adjacent to the needle of the trigger, or with a protrusion on the first arm of the actuating lever, which is located adjacent to said needle of the trigger. With respect to said needle of the trigger, the pivot point of the movable contact is located at least approximately in the line of displacing said needle and in front of it, wherein the first arm of the actuating lever and the seat of the disconnecting lever are located within the area between the movable contact and the needle. The movable contact is optionally maintained apart from the fixed contact by means of resting the seat of the disconnecting lever onto the resting surface of the first arm. Besides, said movable contact may optionally also be maintained apart from the fixed contact by means of resting the seat of the actuating lever onto the resting surface of the first arm. Consequently, in the arrested state of the actuating handle, which corresponds to position of the actuating handle when the electric circuit throughout the switch is established, the movable contact is allowed to be pivoted from its resting position on the fixed contact into another position apart from said fixed contact independently with regard to position of the disconnecting lever and the actuating handle. Accordingly, the movable contact is allowed independently with regard to position of the disconnecting lever and the actuating handle to be pivoted from its resting position on the fixed contact, in which the longitudinal axis of the spring extends apart from the pivot point of said movable contact on the closely to the needle of the trigger located side, into another position apart from the fixed contact, in which the longitudinal axis of the spring extends apart from the pivot point of said movable contact on the remote side with respect to the needle of the trigger.

On the other hand, in the second end position of the actuating handle, which corresponds to position of said handle by the interrupted electric circuit throughout the switch, in which the free end of the engaging clasp is located between the second arm of the actuating lever and the seat of the disconnecting lever, the movable contact is maintained apart from the fixed contact, wherein in the longitudinal axis of the spring extends apart from the pivot point of said movable contact on the closely to the needle of the trigger located side of said pivot point. Accordingly, in the intermediate position of the actuating handle, which corresponds to the position of said handle by the interrupted circuit throughout the switch due to the presence of the short circuit current, the movable contact is by means of the seat on the disconnecting lever maintained apart from the fixed contact, wherein in the longitudinal axis of the spring extends apart from the pivot point of said movable contact on the closely to the needle of the trigger located side of said pivot point.

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

Fig. 1 is a schematically presented protective electric switch according to the invention;

Fig. 2 is a switch according to Fig. 1 , by which for the purposes of some better presentation certain parts of the switch mechanism are removed;

Fig. 3 is a switch according to Fig. 2 during actuation i.e. switching-off due to thermal overload of electric circuit;

Fig. 4 is a switch according to Fig. 2 during actuation due to short circuit current;

Fig. 5 is a switch according to Fig. 2 by shifting a movable contact due to a short circuit current;

Fig. 6 is a position of the actuating lever after switch-off due to excess current in a switch, presented in accordance with Fig. 1 ; and

Fig. 7 is a switch as shown in Fig. 2 upon disconnection thereof.

Generally, at least when taking into consideration a shape and dimensions of the casing 1 as well as integration thereof into each desired electric installation including introduction thereof into each desired electric circuit, a protective electric switch can be created similarly or even identically like a known switch according to prior art, e.g. according to EP 1 488 438 Bl.

Said casing may be identical to those described in EP 1 488 438 Bl and consists of an electric insulating material and is furnished with two electric connectors, which are not separately shown in the drawing but are intended for connecting of electricity supplying wires. A fixed contact 2 and a movable contact 3 (Fig. 3) and are foreseen within said casing 1, which both consist of an electric conductive material are adapted to cooperate with each other and are each per se electrically interconnected with a corresponding connector on the casing 1. Moreover, a trigger 4 is foreseen within the casing 1 , which may also correspond to those known in the prior art and which consists of an electric coil 41, a bimetallic washer 42 as well as of a needle 43, which is movable in its axial direction either by means of a magnetic force generated by said coil 41 or by means of compression force generated by said bimetallic washer 42. At a pre-determined temperature, which may in the practice result from a thermal overload of an electric circuit, said needle 43 is moved in a desired direction by means of said bimetallic washer 42. Quite similar, the needle 43 is moved in a desired direction by means of the electric coil 41, whenever an appropriate magnetic force is generated due to the presence of a short circuit current within the electric circuit in the area of the coil 41. The intensity of said magnetic force is proportional to current, so that in the presence of the short circuit current the force of pushing the needle 43 is then essentially higher than the force of pushing said needle 43 by means of e.g. the bimetallic washer 41.

Still further, a disconnecting mechanism 5 is foreseen within said casing 1 , which will be disclosed in more detail later-on and which is on the one hand adapted to cooperate with the movable contact 3 and on the other hand connected with an actuating handle 6, which is pivotally embedded within the casing 1, although an actuating portion 66 thereof protrudes outside from said casing l .Said handle 6 is pivotally embedded within the casing 1 in the pivot point 60 and on the first end portion 61 on the one side of said pivot point 60 comprises said actuating portion 66, while on the opposite end portion 62 located within the casing 1 the handle 6 is interconnected with an engaging clasp 53, by means of which said handle 6 is linked to a disconnecting mechanism 5 and by means of this last also connected with the movable contact 3, which will be described later.

Said disconnecting mechanism 5 is merely intended for displacing the movable contact 3 depending on each impulse received from the trigger 4 either into its first position, in which it is rest on the fixed contact 2, or into its second position apart from said fixed contact 2, in which it is rest on a not-shown seat.

Accordingly, the disconnecting mechanism 5 comprises a disconnecting lever 51 (Fig. 1), which can be pivoted around its pivot point 510 on the casing 1, as well as an actuating lever 52, which can be pivoted around its pivot point 520 on said disconnecting lever 51 (Fig. 2 - 4), as well as said engaging clasp 53, by means of which the actuating lever 52 is interconnected with the actuating handle 6, namely with the second end portion 62 thereof.

As evident in Figs.l - 7, the pivot point 60 of the lever 6 is located within the casing 1 above the trigger 4 and approximately about the needle 43 and the bimetallic washer 42. By taking into consideration a direction of actuating the needle 43 either by means of bimetallic washer 42 or by means of the coil 41, both the disconnecting mechanism 5 and the movable contact 3 are located in front of the trigger 4, while the movable contact 2 is located below said trigger 4 and the movable contact 3 may be rest thereon in front of the trigger 4.

The movable contact 3 is generally created in the form of a lever, which may be pivoted in its pivot point 30 on the casing 1, and comprises an arm 31, which protrudes apart from said pivot point 30 in a direction towards the fixed contact 2 and is adapted to be rest onto said fixed contact 2, and moreover a seat 32, which is inclined with respect to said arm 31 around the pivot point 30 and id adapted for attachment of a tension spring 7, which is preferably a tension helical spring and is tensioned between said seat 32 on the movable contact 3 and a corresponding tooth 515 located on the circumference of the disconnecting lever 51 adjacent to the actuating handle 6 and at a corresponding distance apart from the pivot point 510 of the actuating lever 51.

A resting surface 310 is foreseen on that side of said arm 31 of the movable contact 31, which is faced towards the trigger 4, and is intended to cooperate with the disconnecting lever 51. by taking into consideration a line 300 between the tooth 515, where the spring 7 is attached to the disconnecting lever 51, and the pivot point 30 of the movable contact 3, the invention provides that the movable contact 30 is able to be pivoted around said pivot point 30 in one or another direction in at least such extent that said seat 32 of the spring 7 may be optionally located either on the one or on the other side of said line 300, so that the longitudinal axis of said spring 7 is located either on the towards the trigger 4 facing side of the pivot point 30 when the movable contact 3 is rest onto the fixed contact 2, or on the opposite side of said pivot point 30 of the movable contact 3 when the movable contact 3 is located apart from said fixed contact 2 and rest on a corresponding seat.

The disconnecting lever 51 of the disconnecting mechanism 5 is designed similarly like in a previously cited switch according to the prior art, and is allowed to be pivoted around its pivot point 510 on the casing 1 of the switch. In view of previously defined location of the pivot point 30 if the movable contact 3 and the trigger 4, the pivot point 510 of this rigid and uniform disconnecting lever 51 is located above the axis of the needle 43 of the trigger 4, and at the same time, the pivot point 30 of the movable contact 3 is located between the pivot point 510 of the disconnecting lever 51 and the trigger 4.

The disconnecting lever 51 is furnished with a first seat 511, which is located adjacent to the actuating handle 6 and apart from the needle 43 of the trigger 4 and is adapted to cooperate with the engaging clasp 53, and moreover with a second seat 512, which is located just in front of the needle 43 and is adapted to cooperate with a resting surface 310 on the first arm 31 of the movable contact 3. A pivot point 520 is arranged on the disconnecting lever 51 between said first and second seat 51 1, 512, where a rigid and uniform double-armed actuating lever 52 is pivotally embedded, the first arm 521 of which protrudes downwardly into the area just in front of the needle 43 of the trigger 4, namely between the needle 43 and the second seat 512 on the disconnecting lever 51, while its second arm 522 extends in the opposite direction upwardly towards the first seat 511 on the disconnecting lever 51. A protrusion 523 is arranged in the arm 521 for the purposes of cooperation with the movable contact 3.

When the switch is disconnected (Fig. 7), the movable contact 3 is rest onto the seat 512 of the disconnecting lever 51 and maintained apart from the fixed contact 2 by means of the force of the spring 7, the central axis of which extends on that side of the pivot point 30 of the movable contact 3, which is faced towards the trigger 4. The handle 6 is located in its first end position according to Fig. 7 corresponding to switch-off position of the switch. The engaging clasp 53, by means of which the handle 6 is interconnected with the disconnecting mechanism 5, is located between the disconnecting lever 51 and the actuating lever 52. A switch-on position of the switch is achieved by means of pivoting said handle 6 into its second end position corresponding to Fig. 5. During said pivoting of the handle 6, the engaging clasp 53 is rest onto the seat 512 of the disconnecting lever 51, which of that reason rotated clockwise around its pivot point 510, by which also the tooth 515 is pivoted, on which the sprig 7 is attached. Consequently, the spring 7 is tensioned, by which also the movable contact 3 is pivoted around its pivot point 30 and pivoting of the seat 512 is followed by pivoting said contact 30 together with the resting surface 310 available thereon. Just prior to arresting of the handle 6, the engaging clasp is passing through its neutral position, upon which it is arrested on the disconnecting lever 51, by which also each movement of the handle in the opposite direction is prevented, and by which a still further pivoting of the disconnecting lever 51 is obtained, in which the seat 512 of the disconnecting lever 51 is positioned apart from the resting surface 310 of the movable contact 3 at least in such extent that by means of the spring 7 the movable contact 3 abuts the fixed contact 2, by which the seat 512 of the disconnecting lever 51 is maintained at a distance apart from the resting surface 310 of the movable contact 3. Upon that the movable contact 3 is by means of the spring 7 maintained in its resting position on the fixed contact 2, by which the circuit throughout the switch is established, while the actuating handle 6 is located in its second end position corresponding to Fig. 5.

When the electric circuit through the switch is established and the movable contact 3 is rest on the fixed contact 2, by thermal overloading of such circuit (Fig. 3) the needle 43 is by means of the bimetallic washer 42 displaced towards the actuating lever 52. As soon as said needle 43 is pressed towards the first arm 521 of the actuating lever 51, which is then rotated around its pivot point 520, by which the second arm 522 abuts the engaging clasp 53, which is then moved beyond its neutral position, by which on the one hand the handle 6 is pivoted into its position according to Fig. 7 by means of the pre-tensioned spring 7, and on the other hand the disconnecting lever 51 is pivoted counterclockwise and initiates the movable contact 3 to pivot around its pivot point 30, by which the movable contact 3 is displaced apart from the fixed contact 2, by which the circuit through the switch is interrupted, while the handle 6 remains located in its position according to Fig. 7.

When the electric circuit through the switch is established and the movable contact 3 is rest on the fixed contact 2, and a short circuit current occurs within such circuit (Fig. 4), a magnet field is generated in the inductive coil 41 of the trigger 4, upon which the needle 43 is promptly ejected towards the actuating lever 52 by means of a sufficient force, wherein by means of such released kinetic energy the actuating lever 52 and thanks to the protrusion 523 the movable contact 3 is then promptly pivoted counterclockwise into its position according to Fig. 3 quite independently with regard to pivoting the disconnecting lever 51 and the handle 6 and prior to performing the lastly mentioned pivoting as such. In such position, the longitudinal axis of the spring 7 is located on that side of the pivot point 30 of the movable contact 3, which is faced away from the trigger 4, where the movable contact 3 is maintained at its utmost distance apart from the fixed contact 2 by means a torque generated by means of said spring 7. Said pivoting of the movable contact is executed within an essential shorter time period than the pivoting of the disconnecting lever 51 and the lever 6. As soon as the disconnecting lever 51 is then pivoted similarly like by the thermal overloading and the engaging clasp 53 is pushed by means of the actuating lever 52 outside from the area between the disconnecting lever 51 and the actuating lever 52, the handle 6 is shifter into its intermediate position according to Fig. 6, which indicates the presence of a short circuit current, and the movable contact 3 is rest onto the seat 512, where it is then maintained at a sufficient distance apart from the fixed contact 2.