EP4623459A1 - Protective electric switch with improved interrupting mechanism - Google Patents

Abstract

The purpose of the invention is to create a protective switch, which should be conceptually simplified in view of feasibility and assembling of components thereof by simultaneously improving reliability in its operation, in particular when the differences among the electric currents through the switch would occur. To this aim, the invention among other provides that a pivot point (57) of an arresting lever (7) on an transmission lever (5) in such switch is arranged in such manner that a rolling member (75) is placed on a cylindrical axle (570), which extends substantially rectangular with respect to the transmission lever (5) and is rigidly connected there-with, wherein said rolling member (75) is loosely and freely rotatably placed on said axle (570) and is secured against undesired removal therefrom, and wherein the arresting lever (7) is loosely and freely rotatably placed on the external circumferential surface of said rolling member (75).

Description

Protective electric switch with improved interrupting mechanism

The invention belongs to electricity, namely to basic electric components i.e. to switches, which are controlled by means of suitable levers, and to construction details of such switches, in particular to switches which are suitable for protection against electric overloads. In accordance to the International Patent Classification (IPC⁹) such inventions belong to the class H OI H 71/52.

In this, the invention is rest on a problem how to improve reliability of operation of such a protective switch, in particular in order to avoiding irregularities by activation, as well as to improve its reacting speed and reliability of interruption of the electric circuit, when the electric circuit, into which such switch is integrated, would operate irregularly, by which simultaneously also the friction and other losses should be minimized in order to avoid decreasing of forces, which are required for acting to those components of the switch, which are crucial for efficient and reliable functioning of the switch. A further aspect of the invention is also a need on establishing a possibility of indication of the reason, why an electric circuit, furnished with such switch, has been interrupted at all, or at least on providing information, if the circuit has been interrupted intentionally or due to a failure. Such a protective switch is generally suitable for protection of appliances integrated into an electric circuit against false current or differential current. This may occur when an electric current, which is connected to a voltage source, would come in contact with the earth, e.g. when a person would be in contact with a part of appliance, which is exposed to voltage, so that the electric current would flow through its body towards the earth. In such cases, all conductors in the circuit need to be interrupted quickly and efficiently, which is in the practice usually achieved by means of known Fl-relays or so-called RCD-switches (Residual Current Protective Device), namely by means of relays, which are adjusted for monitoring the sum of all incoming currents and the sum of all outgoing currents within all disposable electric conductors. If in certain situation a part of said currents would flow directly to the earth, then the difference between them would not equal zero, which would lead to reaction and triggering of such relay.

One of such protective switches is disclosed in EP 2 485 237 Al and comprises a casing, which consists of electric insulating material and is furnished with connectors for connecting of input and output electric conductors, which are within the interior of the casing either interconnectable or interruptible by means of interrupting members, which are mounted on a contactor shaft, so that each one of said interrupting members belongs to one of said electric conductors. By rotating said contactor shaft, said interrupting members are simultaneously displaceable from their first position, in which the electric circuit there-through is connected, into their second position, in which the electric circuit there-through is interrupted, or vice versa. Moreover, a Fl-relay is also integrated within said casing and is intended for detecting of potential difference among the currents. Said Fl-relay is both from mechanical aspects and also from the electrical aspect a pretty sensible appliance, which includes a triggering means, which is by detecting said current difference displaced outwardly from the relay casing and is able to generate only a relatively small force in amount of several dN. However, said displacement of the triggering means and the force generated therewith are the basis for achievement of rotation of said interrupting shaft, which need to be realized at a sufficient extent and in a shortest possible time in order to assure a sufficient and simultaneous movement of all contact members apart from all disposable electric conductors. To this aim, an interrupting mechanism is foreseen between said triggering means and said contactor shaft, the purpose of which is generating a sufficient force or torque for rotation of said contactor shaft on the basis of said weak impulse produced by said Fl-relay on the basis of potentially detected current difference. Such interrupting mechanism, among others, includes a control lever, which protrudes outwardly from the casing and is as such also connected with said contactor shaft, so that the contactor shaft may also be rotated by means of said control lever in order to either activate the switch due to establishing the electric circuit there-through, or in the need also to deactivate the switch in order to interrupt the electric circuit there-through manually. Such interrupting mechanism according to EP 2 485 237 Bl further comprises a two-arm triggering lever, which is pivotally embedded in a suitably arranged pivot point, and the first arm of which is longer and is adjusted for cooperation with said triggering means of the Fl-relay, while its other arm is shorter and is furnished with a preciously curved surface, on which said lever is rest when it is in placed on a protrusion on the contactor shaft and which is also preciously curved in a re-determined manner. A torsional spring is mounted within the interior of said two-arm lever, by means of which, as mentioned in said document, said first arm of the lever is pressed towards the triggering means of the Fl-relay with a constant force, by which undesired triggering due to mechanical vibrations may be avoided. As soon as such protective switch is activated, said triggering means is displaced towards the interior of the Fl-relay, while the other arm is supported by said protrusion on the contactor shaft, so that both of them are thanks to said preciously curved surfaces mutually jammed and by means of friction maintained in such position, while the first arm is held at a distance apart from the triggering means of the Fl-relay. When the current difference occurs, said triggering means is displaced outwardly from the casing of the Fl-relay and abuts the first arm of the triggering lever, which is then pivoted for at least such extent that said protrusion on the contactor shaft starts sliding and moving along the surface of the second arm of the lever, which leads to rotation of the contactor shaft with interrupting members for certain angle, by which then the electric circuit is interrupted. Such concept obviously requires application of extremely complicated and precious components, manufacturing of which is quite difficult, and in addition to that, also the functioning appears to be pretty complicated and not quite reliable. Starting from sensibility of the Fl-relay and a relatively weak force, which is generated as an output signal, there is a doubt, whether a mechanism, in which the complete cinematic effects rely on sliding, friction and even jamming between the components, in various situations and circumstances, in various conditions and environments during a long-term use really enables a quick and reliable mutual interaction of components, which could lead to prompt reaction of the contactor shaft in the sense of its rotation and interruption of the electric circuit. Moreover, as mentioned in said document, the force of the spring within said lever should act in a direction towards the triggering means of the Fl-relay, so that there is also a possibility that in certain circumstances, despite to triggering of the Fl-relay, said force on the triggering means of the Fl-relay might even be insufficient for generating a sufficient displacement of the triggering lever, which could terminate the interaction between the second arm of the triggering lever and the protrusion of the contactor shaft in order to allow rotation of the contactor shaft. In addition to that, whenever such switch is in use and the user would detect that the switch has been switched-off, it is quite impossible to find out at the first glance, if disabling of the switch results from the current difference, or the appliance has been switched-off intentionally due to temporarily interruption of the electric circuit by means of pivoting a control lever, e.g. by another user.

Still further, a protective switch with improved interrupting mechanism is disclosed in SI 26113 A, and generally comprises

- a casing, which consists of electric insulating material and is furnished with connectors which are suitable for establishing a connection with electric conductors within the casing with conductors in each disposable electric circuit and thus integration of said switch into said disposable electric circuit;

- a contactor shaft, which is pivotally in one or another direction embedded in a pivot point within said casing and is furnished with radially outward, with respect to said pivot point, and apart from each other protruding arms, which are firmly interconnected with said contactor shaft and are therefore also rotatable together with it, namely an interrupting arm, which is adjusted to cooperate with interrupting members suitable for interconnecting or interrupting of electric conductors, as well as a control arm, which is adjusted for rotation of the contactor shaft in one or another direction around its pivot point, so that said electric conductors within the casing of the switch are, each per se, either simultaneously interrupted or simultaneously interconnected by means of simultaneous displacement of the belonging interrupting members due to rotation of the connector shaft around its pivot point within the casing;

- a control lever, by which said contactor shaft is mechanically interconnected and which is pivotally between its both terminal positions embedded in its own pivot point within said casing of the switch, wherein said control lever comprises a control button, which is arranged outside of the casing and at certain distance apart from said pivot point of the control lever, so that said control button is either an integral part of the control lever or is firmly interconnected there-with, and wherein said control lever is pivotal by means of said control button from the outside of the casing and without reaching the interior of the casing, so that by pivoting said control lever also said contactor shaft is rotated in one or another direction around its pivot point, since it is mechanically interconnected there-with; as well as

- a Fl-relay, which is mounted within said casing and is adjusted for monitoring of operation, in particular for detecting of potential current difference within the electric conductors, and which comprises a triggering means, which is displaceable i.e. extendable at a pre-determined distance in a desired direction due to triggering of a suitable interrupting mechanism of the switch, which is adjusted to cooperate with it.

In such a switch, a triggering lever is pivotally embedded within said casing in the adjacency of said Fl-relay and within the reach of the triggering means thereof, wherein said triggering lever is in the area of its pivot point furnished with a suitable seat, which is adjusted for resting of a transmission lever of the interrupting mechanism, wherein said interrupting mechanism, via which on the one hand by pivoting of the control lever and consequently also by rotating the contactor shaft said electric conductors are connectable, or via which on the other hand on the basis of an impulse from the side of the triggering means on the FI- relay and rotation of the contactor shaft in the opposite direction electric conductors are interruptible, is conceived in such a manner i) that said control lever and said contactor shaft are mechanically connected with each other in such a manner, that a further pivot point is arranged on said control handle at a distance apart from said pivot point of the control lever as such in a direction away from the control button, namely within the interior of the casing, and a rigid primary arm is attached with its first terminal portion to the control handle in this further pivot point, the second terminal portion of which is in a pivot point pivotally connected with the first terminal portion of the secondary arm, which is in a pivot point arranged in the area of its second terminal portion pivotally attached to said control arm of the contactor shaft; ii) that a two-arm transmission lever is pivotally embedded in its pivot point within the casing, the primary arm of which is on its terminal area furnished with a seat, which is adjusted for resting on said seat on the triggering lever as long as the triggering lever is maintained in its nonpivoted position prior to activation of the Fl-relay, while upon activation of the Fl-relay and pivoting the triggering lever at a sufficient angle by simultaneously changing position of said seat, said primary arm of the transmission lever is disengaged from resting on said seat on the triggering lever and is during pivoting around its pivot point freely displaceable across the pivot point of the triggering lever, and the secondary arm of which is adjusted to be rest on the control arm of the contactor shaft; iii) that the first attachment point of a transmission spring is arranged on said primary arm in the area between said seat in the terminal area thereof and said pivot point of the transmission lever, while the second attachment point of said spring is arranged on the control arm of the contactor shaft; iv) that a two-arm arresting lever is pivotally attached to said transmission lever in a further pivot point arranged in the central region thereof and adjacent to the pivot point of the transmission lever as such, wherein the primary arm of the arresting lever extends in a direction towards the pivot point between the primary arm and secondary arm of the control lever, while the secondary arm of the arresting lever protrudes in a direction substantially towards the triggering lever, wherein an arresting recess is arranged on the primary arm, into which said pivot point between the arms of the control lever is insertable, so that the primary arm is permanently maintained in contact with said pivot point between both control lever arms, and said arresting lever as such permanently follows each changes of position of said pivot point by pivoting of the control lever and by displacing of the primary arm and the secondary arm, and wherein an attachment point of a retaining spring is arranged on the secondary arm of the arresting lever, while said spring is on the other hand also attached to the other attachment point on the triggering lever.

Whenever said control lever is shifted to its first terminal position, which corresponds to rotation of the control shaft into a position, in which the electric contacts are uninterrupted, the pivot point of the primary arm on the control lever and also the pivot point between the primary arm and the secondary arm of the control lever, with which said arresting lever is engaged, are both arranged on the same side of a line, which extends through the pivot point of said control lever and the pivot point of the secondary arm on the control arm of the contactor shaft.

Whenever said control lever is shifted to its second terminal position, which corresponds to rotation of the control shaft into a position, in which the electric contacts are interrupted, said coupling of control lever arms is collapsed in such a manner, that, relative to said line through the pivot point of the control lever and the pivot point of the secondary arm of the control lever on the control arm of contactor shaft, said pivot point between the arms is still positioned on the same side of the previously mentioned line, while the pivot point of the primary arm of the control lever is displaced to the other side of said line, wherein however such position is despite to said collapsing still stable, since the transmission lever is rest on the control arm of the contactor shaft.

However, a problem might occur during a long-term operation, since the arresting lever and the transmission lever are arranged adjacent to each other, which might lead to reduced reliability of such switch due to hindered pivoting capability of the arresting lever relatively to the transmission lever, which could essentially decrease sensibility of such switch in particular in detecting of current differences.

I order to avoid such deficiencies, the invention proposes that the pivot point of the arresting lever on the transmission lever is arranged in such manner that a rolling member is placed on a cylindrical axle, which extends substantially rectangular with respect to the transmission lever and is rigidly connected there-with, wherein said rolling member is loosely and freely rotatably placed on said axle and is secured against undesired removal there-from, and wherein the arresting lever is loosely and freely rotatably placed on the external circumferential surface of said rolling member.

In a preferred embodiment of the invention said rolling member is uniformly conceived and is on the one of its terminal portions ended by a disc-shaped area, the outer diameter of which is larger than the outer diameter of the longitudinal section of the rolling member, on which the arresting lever is rest. In addition to that, said disc-shaped area on the rolling member is, when observed in the longitudinal direction of said cylindrical axle, located in the area between the arresting lever and the transmission lever. Said axle may optionally consist of a metallic material and may comprise a smooth circumferential surface, while the rolling member may consist of a wear-resistant thermoplastic material with lowest possible friction coefficient by sliding along a smooth metallic surface.

Said transmission spring is preferably a tension helical spring, which is extended by manually pivoting of the control handle and consequently pivoting of the transmission lever and rotation of the contactor shaft toward so its first terminal position, in which the electric conductors are uninterrupted, and is in its extended position capable of accumulating of at least such amount of energy, which is sufficient for pivoting of the control lever by simultaneously rotating the contactor shaft into its second terminal position, in which the electric conductors are interrupted.

Said retaining spring is preferably a tension helical spring, which is adapted for accumulating of essentially less energy than the transmission spring, and which is in its initial position, when the switch has not yet been activated i.e. prior to triggering of the Fl-relay, minimally tensioned, namely only in such extent that the triggering lever is retained in its initial position, which allows the transmission lever to be supported by resting of its seat onto the seat of the triggering lever, and the tension in the retaining spring is intensified upon triggering of the Fl-relay and pivoting of the triggering lever during pivoting of the transmission lever with simultaneously pivoting of the control lever, so that said intensified tensioning of the retaining spring efficiently supports the arresting lever during its following to changes of position of the control lever, namely position of the pivot point between the primary arm and the secondary arm of the control lever. In a further embodiment of the invention, which additionally enables identification of the reason, why the electric circuit through the protective switch is interrupted, said arresting lever is furnished with a further spring, which is a torsion spring, the first arm of which is rest on a limiting member on the secondary arm of the arresting lever adjacent to the attachment point of the retaining spring, while the second arm of which is rest on the limiting member on the transmission lever. Said torsion spring is adjusted in such a manner that the control lever, which is pivoted by means of energy, which is released from the transmission spring, is by means of said torsion spring stopped in its intermediate position between its both terminal positions and regardless to any further rotation of the contactor shaft, upon which the control handle is via the control button thereon manually displaceable into each desired terminal position.

The invention still further provides that the pivot point between the primary arm and the secondary arm of the control lever is furnished with a rolling member, and that simultaneously the arresting recess on the arresting lever is adjusted for cooperation with said rolling member.

The invention will be explained in more detail on the basis of embodiments, which are presented in the attached drawings, wherein

Fig. 1 is an isometric view of a symbolically presented protective electric switch according to the invention with partially removed casing;

Fig. 2 is a schematically presented interrupting mechanism of an activated switch according to Fig. 1, in front view;

Fig. 3 is a schematically presented interrupting mechanism of the switch according to Fig. 1, in position upon triggering of a Fl-relay and engagement of a triggering lever, again in front view; Fig. 4 is a schematically presented interrupting mechanism of the activated switch according to Fig. 1, in position upon triggering of a Fl-relay and establishing of its deactivated state, again in front view;

Fig. 5 is a schematically presented interrupting mechanism of the activated switch according to Fig. 2, however upon removal of several components, when observed from opposite direction i.e. in rear view;

Fig. 6 is a schematically presented interrupting mechanism of the activated switch according to Fig. 4, however upon removal of several components, when observed from opposite direction i.e. in rear view;

Fig. 7 is a further embodiment of said switch, which allows indication of a reason for deactivation of the switch and interruption of an electric circuit, in which the switch is integrated;

Fig. 8 is one of further possible aspects of the switch, namely resting of the arresting lever on the pivot point between the control lever arms, namely a detail A;

Fig. 9 is an isometric presentation of the switch according to the invention without the casing;

Fig. 10 is separately and symbolically presented arresting lever with the belonging rolling member and a cylindrical axle of the pivot point on the transmission lever, in isometric view;

Fig. 11 is, similarly like in Fig. 10, an arresting lever of the switch, but in front view; and

Fig. 12 is an arresting lever in longitudinal cross-section along the plane X - X according to Fig. 10.

For the purposes of explaining and understanding this invention the expression “activated” switch means a switch, which is integrated within a disposable electric circuit and is ready for monitoring a situation within the electric circuit. The switch in its activated state is therefore conductive for electric current and enables undisturbed operation of the electric circuit. As soon as however such a switch would indicate pre-defined irregularities in operation of the electric circuit, then the switch would, upon performing of all pre-determined steps, be transformed into its “deactivated” state, in which conduction of current throughout the switch is disabled, so that the electric current is interrupted and is maintained in such a state until the activated status of the switch is re-established.

A switch according to the invention generally comprises a casing 1, which consists of electric insulating material and is furnished with not-shown connectors which are suitable for establishing of connection of electric conductors in a corresponding electric circuit. Electric conductors 101’, 101”, 101”’ within the casing 1, which are connectable with corresponding electric conductors of each disposable electric circuit, are simultaneously connectable or interruptible by means of simultaneously displacing of corresponding interrupting members on a contactor plate 2, which are not separately shown but are simultaneously displaceable by means of an interrupting mechanism, which is presented in Figs. 2 - 8 and with which said contactor shaft 2 is mechanically connected and is consequently rotatable in one or another direction around its pivot point 20, which is available within said casing 1, namely on a rigid plate 10, which is in the shown embodiment mounted within the casing 1. To this aim, said contactor shaft 2 s furnished with at least two radially outward, with respect to said pivot point, and apart from each other protruding arms 21, 22, which are firmly interconnected with said contactor shaft 2 and are therefore also rotatable together with it. An interrupting arm 21 is adjusted to cooperate with interrupting members suitable for interconnecting or interrupting of electric conductors 101 ’, 101 ”, 101 ’”, while a control arm 22 is which is adjusted for rotation of the contactor shaft 2 in one or another direction around its pivot point 20.

Said contactor shaft 2 is mechanically interconnected with a control lever 3, which is pivotally between its both terminal positions embedded in its own pivot point 30 within said casing 1 of the switch. Said control lever 3 comprises a control button 31 , which is arranged outside of the casing 1 and at certain distance apart from said pivot point 30 of the control lever, so that said control button 31 is either an integral part of the control lever 3 or is firmly interconnected there-with, and wherein said control lever 3 is pivotal by means of said control button 31 from the outside of the casing 1 and without reaching the interior of the casing 1 , so that the control lever 3 can be by means of said control button 31 pivoted from its first terminal position to its second terminal position, or vice versa. Moreover, a further pivot point 32 is arranged on said control lever 3 within the casing 1 and at a distance apart from its own pivot point 30 in a direction away from the control button 31, in which pivot point 32 a rigid primary arm 33 is with its first terminal area 33’ pivotally connected to the control arm 3, while its second terminal area 33” is in a pivot point 35 pivotally connected with the first terminal portion 34’ of a secondary arm 34, the second terminal area 34” of which is in a pivot point 24, which is arranged at a distance apart from said pivot point 20 of the contactor shaft 2, pivotally connected with said control arm 22 of the contactor shaft 2. Thanks to such concept, e mechanical interconnection is established between the contactor shaft and the control lever 3, wherein the first i.e. initial terminal position of the control lever 3 upon activation of the switch corresponds to rotation of the contactor shaft 2 into its first terminal position (Fig. 2), in which the electric conductors 101’, 101 ”, 101” are interconnected i.e. uninterrupted, while the second terminal position of the control lever 3 upon deactivation of the switch corresponds to rotation of the contactor shaft 2 into its second terminal position (Fig. 4), in which the electric conductors 101’, 101 ”, 101 ”’ are interrupted. Functioning of said control arm 3 and said contactor shaft 2 is due to said mechanical interconnection between them via said arms 33, 34 and the pivot point 35 synchronized, so that each pivoting of the control handle 3 around its pivot point 30 leads to rotation of the contactor shaft 2 around its pivot point 20, or vice versa, namely that also each rotation of the contactor shaft 2 leads to pivoting of the control arm 3.

Furthermore, a Fl-relay 44, which is as such known to those skilled in the art, is mounted within said casing 1 and is adjusted for monitoring of operation, in particular for detecting of potential current difference within said electric conductors 101’, 101 ”, 101’”, and which, from quite mechanical aspects, comprises a (not-shown) triggering means, which is displaceable i.e. extendable at a pre-determined distance in a desired direction, which is in Figs. 2 and 5 marked with arrows 4’, towards the triggering lever 4 of the switch. Said triggering lever 4 is pivotally around its pivot point 40 embedded within said casing 1 and is in the area of said pivot point 40 furnished with a suitable seat 45. As shown in Figs. 2 and 3, the triggering lever 4 is together with said seat 45 pivotal around its pivot point 40 at a relatively small angle, and pivoting of the triggering lever 4 is initiated by triggering of said Fl-relay 44, namely when said triggering means of the Fl-relays abuts it with a relatively small force.

Still further, a transmission lever 5 is embedded within said casing 1 , and is pivotal around its pivot point 50, wherein a primary arm 51 thereof is at its terminal portion 510 furnished with a seat 515, which is adjusted on the one hand for resting onto said seat 45 of the triggering lever 4, when the last is positioned in a suitable position prior to triggering of the Fl-relay 44, while on the other hand, upon sufficiently pivoting of the triggering lever 4 and changing of position of the seat 45, it is releasable from the engagement with said seat 45 on the triggering lever 4, upon which it is during pivoting of the transmission lever 5 around its pivot point 50 freely displaceable across the pivot point 40 of the triggering lever 4. A secondary arm 52 of the transmission lever 5is adjusted for resting onto the control arm of the contactor shaft 2.

An attachment point 56 of a transmission spring 6 is arranged on the primary arm 51 of the transmission lever 5 in the area between the seat 515 on its terminal area 510 and its pivot point 50, while the other attachment point 26 of said spring 6 is arranged on the control arm 22 of the contactor shaft 2. Said transmission spring 6 is a relatively strong tension spring, in the shown embodiment a helical tension spring, which is capable of accumulating sufficient amount of energy, which should enable pivoting of the transmission lever 5 around its pivot point 50 by simultaneously displacing the control arm 22 of the contactor shaft 2 and consequently rotation of the shaft 22, which consequently via the levers 33, 34 leads also to pivoting of the control lever 3. In this, said transmission spring 6 is maximally tensioned in such position, in which the transmission lever 5 (Fig. 2) is by means of the seat 515 on the primary arm 51 of the transmission lever 5 rest onto the seat 45 of the triggering lever 4. As soon as the Fl-relay 44 is activated, position of the seat 45 is changed by pivoting of the triggering lever 4, by which the seat 515 on the primary arm 51 of the transmission lever 5 is not supported anymore and the transmission lever 5 is (Figs. 2 - 4) due to action of the force of the transmission spring 6 pivoted around its pivot point 50 at certain angle, by which also the contactor shaft 2 is rotated around its pivot point 20, which results in a prompt and simultaneous interruption of the electric current through all disposable electric conductors 101’, 101”, 101’”. As explained later-on, at the same time also the control lever 3 is pivoted.

Namely, a two-arm arresting lever 7 is pivotally attached to said transmission lever 5 in a further pivot point 57 arranged in the central region thereof and adjacent to the pivot point 50 of the transmission lever 5 as such, wherein the primary arm 71 of the arresting lever 7 extends in a direction towards the pivot point 35 between the primary arm 33 and the secondary arm 34 of the control lever 3, while the secondary arm 72 of the arresting lever 7 protrudes in a direction substantially towards the triggering lever 4. An arresting recess 710 is arranged on said primary arm 71, into which said pivot point 35 between the arms 33, 34 of the control lever 3 is insertable, so that said primary arm 71 is permanently maintained in physical contact with said pivot point 35 between both control lever arms 33, 34, and said arresting lever 7 as such is permanently forced to follow any change of position of said pivot point 35 by pivoting of the control lever 3 and by displacing of the primary arm 33 and the secondary arm 34. An attachment point 78 of a retaining spring 8 is arranged on the secondary arm 72 of the arresting lever 7, while said retaining spring 8 is on the other hand in the other attachment point 48 also attached on the triggering lever 4 (Figs. 5 and 6). Said retaining spring 8 is a tension spring, preferably a helical tension spring, which is however adapted for generating of essentially smaller force than the transmission spring 6. Moreover, said retaining spring 8 is in its initial position, when the switch has not yet been activated i.e. prior to triggering of the Fl-relay 44, just minimally tensioned, namely only in such extent that the triggering lever prior to activation of the FI- relay 44 maintained in its initial position, which allows the transmission lever 5 to be stable and reliably supported by resting of its seat 515 onto the seat 45 of the triggering lever 4. Consequently, the impact of the retaining spring 8 to mov ability of the triggering lever 4 is therefore minimized by such a concept, so that the triggering lever 4 is easily displaceable in sufficient extend despite to said relatively weak force, which can be generated by means of said Fl-relay 44. Namely, extension of the retaining spring (5) and increasing of forces therein occurs after triggering of the Fl-relay 44 and pivoting of the triggering lever 4, by pivoting of the transmission lever 5 with simultaneously rotating the contactor shaft 2 and pivoting of the control lever 3, wherein said intensified tensioning of the retaining spring 8 is quite useful, since in such circumstances the arresting lever 7 can then easily follow every change of position of the control lever 3, namely changes of position of the pivot point 35 between the primary arm 33 and the secondary arm 34 of the control lever 3.

In the activated position of the switch according to Fig. 1, the triggering lever 4 is maintained in its initial position adjacent to the Fl-relay 44, in which corresponding position of the seat 45 on the triggering lever 4 allows supporting of the transmission lever 5 in the area of the seat 515. The triggering lever 4 is maintained in such position by means of a force, which is generated by means of minimally tensioned retaining spring 8. The control lever 3 is maintained in its terminal position, in which the pivot point 32 of the primary arm 33 on the control lever 3 and the pivot point 35 between the primary and secondary arm 33, 34, with which the arresting lever 7 is engaged, are both arranged on the same side of the line, which extends through the pivot point of the control lever 3 and the pivot point 24 of the secondary arm 34 on the control arm 22 of the contactor shaft 2. Thus, due to the force, which is produced by the transmission spring 6, which has been tensioned by means of pivoting the control handle 3, and due to arresting of the arresting lever 7 in the pivot point 35 between the arms 33, 34 of the control lever 3, said transmission lever 5 is maintained in its position of resting on the seat 45 of the triggering lever 4, while the contactor shaft 2 is rotated into its position, in which the electric conductors 101 ’, 101 ”, 101 ’” are uninterrupted.

By triggering of the Fl-relay, when e.g. an irregularity in operation of the electric circuit would occur, the triggering means of the Fl-relay 44 abuts the triggering lever 4, which is due to this impact just temporarily pivoted at a pre-determined angle, wherein by such a pivoting of the triggering lever 4 position of the seat 45 on the triggering lever 4 is changed to such extent that resting of the seat 515 of the transmission lever 5 on the seat 45 of the triggering lever 4 is dismissed, so that due to tensioning force of the transmission spring 6 on the one hand the transmission lever 5 is pivoted around its pivot point 50, by which the position of the arresting lever 7, which is attached thereto, also changes, while simultaneously due to said action of the transmission spring 6 also the contactor shaft 2 is rotated, which leads to prompt and simultaneous interruption of the electric conductors 101’, 101”, 101 ’”. Such release of energy in said transmission spring 6 and rotation of the contactor shaft 2 also leads to displacement of the secondary arm 34 and the primary arm 33 of the control lever 3, wherein the arresting lever 7, which is all the time loaded by the increasing force of the retaining spring 8, which simultaneously returns the triggering lever 4 back to its initial position, is still maintained in engagement with the pivot point 35, which leads to pivoting of the control lever 3 around its pivot point 30 and displacement of the control button 31 in its another terminal position, by which said coupling of said arms 33, 34 of the control lever 3 is collapsed in such manner that with respect to the previously mentioned line between the pivot point 30 of the control lever 3 and the pivot point 24 of the secondary arm 34 of the control lever 3 on the control lever 222 of the contactor shaft 2 the pivot point 35 is still located on the same side of the said line, while the pivot point 32 of the primary arm 33 is displaced on the another side of the said line, wherein also in such position and despite to said collapsing, situation is in fact still stable due to resting of the transmission lever 5 on the control arm 22 of the contactor shaft 2.

As soon as the reason for interruption of the electric circuit is eliminated, the electric circuit through the electric conductors 101 ’, 101”, 101 ”’ can be reestablished by means of pivoting of the control button 31 and the control lever 3 around the pivot point 30, wherein on the one hand the contactor shaft 2 is rotated, and on the other hand during tensioning of the transmission spring 6 and releasing of the retaining spring 8 the transmission lever 5, which is connected with the arresting lever is due to cooperation between the last and the pivot point 35 returned back to its initial position, in which it is rest on the seat 45 of the triggering lever 4, wherein also the arms 33, 34 are displaced so that the pivot points 32, 35 are located in their initial position on the first side of the line between the pivot point 30 of the control lever and the pivot point 24 of the secondary arm 34 on the contactor shaft 2. Upon that, the switch is capable again for regular operation and protecting the electric circuit against potential irregularities, which are then detected by the said Fl-relay, which is adjusted to react with appropriate impact in a direction towards the triggering lever 4.

In another embodiment of the switch according to Fig. 7, said arresting lever 7 is furnished with a further spring 77, which is a torsion spring, the first arm 771 of which is rest on a limiting member 771’ on the secondary arm 72 of the arresting lever 7 adjacent to the attachment point 720 of the retaining spring 8, while the second arm 722 of thereof is rest on the limiting member 772’ on the transmission lever 5. The presence of said torsion spring 77 within the switch enables an additional possibility of detection of the reason, why the electric circuit throughout the switch has been interrupted. An automatic switch-off, e.g. due to current difference within the electric circuit, in which the switch is integrated, also in such an embodiment leads to triggering of the Fl-relay 44, pivoting of the triggering lever 4 and to pivoting of the transmission lever 5 and rotation of the contactor shaft 2 as a consequence of releasing of the transmission spring 6, wherein however during the rotation of the contactor shaft 2 pivoting of the control lever 3 is interrupted due to action of said torsion spring 77, and the control lever 3 is stopped in its intermediate position between its both terminal positions. Displacing of the control lever 3 from said intermediate position into anyone of its terminal positions is possible by manually displacing the control button 31. As a consequence, during the use of the switch according to the invention, each user can always get an information just from the position of the control lever, which s the reason for interruption of the electric circuit, namely if the interruption results from a failure within the electric circuit, other the electric circuit has been interrupted intentionally by another person.

In accordance with a still further aspect of the invention, in order to minimize friction and mechanical losses, the invention proposes that the pivot point 35 between the primary arm 33 and the secondary arm 34 of the control lever 3 is furnished with a rolling member 350, and that simultaneously the arresting recess 710 on the arresting lever 7 is adjusted for cooperation with said rolling member 350. Such a measure may on the one hand lead to essential reduction of friction between the pivot point 35 and the recess 710 on the arresting lever 7, while on the other hand a rotatable roller member 350 with a larger outer diameter allows still better mutual engagement with the recess 710, which may increase reliability of engagement between the arresting lever 7 and the control lever 3 during pivoting of the primary arm 33 and the secondary arm 34. In the context of resolving of the initially mentioned technical problem, the switch according to the invention is conceived in such a way that said pivot point 57 of the arresting lever 7 on the transmission lever 5 is arranged in such manner that a rolling member 75 is placed on a cylindrical axle 570, which extends substantially rectangular with respect to the transmission lever 5 and is rigidly connected therewith, wherein said rolling member 75 is loosely and freely rotatably placed on said axle 570 and is secured against undesired removal there-from, and wherein the arresting lever 7 is loosely and freely rotatably placed on the external circumferential surface of said rolling member 75. This means that on the one hand the rolling member 75 as such is freely rotatable relatively to said axle 570 in the pivot point 57, while on the other hand the arresting lever 7 is pivotal relatively to the axle 570 and the transmission lever 5 either together with the roller member 75 or alone around said roller member 75. Such, even if the friction between the axle 570 and the roller member 75 would increase due to any reason, an unhindered alternative displacement of the arresting means 7 relatively to the transmission lever 5 would always still persist. In this, said rolling member 75 can be uniformly conceived and is on the one of its terminal portions ended by a disc-shaped area 750, the outer diameter of which is larger than the outer diameter of the longitudinal section of the rolling member 75 on which the arresting lever 7 is rest. In this, said disc-shaped area 750 on the rolling member 75 is, when observed in the longitudinal direction of said cylindrical axle 570, located in the area between the arresting lever 7 and the transmission lever 5. By placing said area 750 into the area between the transmission lever 5 and the arresting lever 7, each potential increasing of friction between these relatively to each other sliding levers 5, 7, which could jeopardize efficient and reliable functioning of the switch, is a priori eliminated. In addition to that, said friction in the area of pivot point 57 between the arresting lever 7 and the transmission lever 5 can be additionally reduced by means of reasonable selection of materials, wherein said axle 570 should consist of a metallic material and should comprises a smooth circumferential surface, while the rolling member 75 should consists of a wear-resistant thermoplastic material with lowest possible friction coefficient by sliding along a smooth metallic surface.

Claims

1. Protective switch with improved interrupting mechanism, said switch comprising

- a casing (1), which consists of electric insulating material and is furnished with connectors suitable for establishing of connection of electric conductors (101’, 101”, 101”’) within the casing (1) with electric conductors of each disposable electric circuit and consequently integration of said switch into said disposable electric circuit;

- a contactor shaft (2), which is pivotally in one or another direction embedded in a pivot point (20) within said casing (1) and is furnished with radially outward, with respect to said pivot point, and apart from each other protruding arms (21, 22), which are firmly interconnected with said contactor shaft (2) and are therefore also rotatable together with it, namely an interrupting arm (21), which is adjusted to cooperate with interrupting members suitable for interconnecting or interrupting of electric conductors (101’, 101”, 101’”), as well as a control arm (22), which is adjusted for rotation of the contactor shaft (2) in one or another direction around its pivot point (20), so that said electric conductors (101 ’, 101”, 101’”) within the casing (1) of the switch are, each per se, either simultaneously interrupted or simultaneously interconnected by means of simultaneous displacement of the belonging interrupting members due to rotation of the connector shaft (2) around its pivot point (20) within the casing (1);

- a control lever (3), by which said contactor shaft (2) is mechanically interconnected and which is pivotally between its both terminal positions embedded in its own pivot point (30) within said casing (1) of the switch, wherein said control lever (3) comprises a control button (31), which is arranged outside of the casing (1) and at certain distance apart from said pivot point (30) of the control lever, so that said control button (31) is either an integral part of the control lever (3) or is firmly interconnected there-with, and wherein said control lever (3) is pivotal by means of said control button (31) from the outside of the casing (1) and without reaching the interior of the casing (1), so that by pivoting said control lever (3) also said contactor shaft (2) is rotated in one or another direction around its pivot point (20), since it is mechanically interconnected there-with; as well as

- a Fl-relay (44), which is mounted within said casing (1) and is adjusted for monitoring of operation, in particular for detecting of potential current difference within said electric conductors (101 ’, 101”, 101 ”’), and which comprises a triggering means, which is displaceable i.e. extendable at a pre-determined distance in a desired direction (4’) due to triggering of a suitable interrupting mechanism of the switch, which is adjusted to cooperate with it, wherein a triggering lever (4) is pivotally embedded within said casing (1) in the adjacency of said Fl-relay (44) and within the reach of the triggering means thereof, wherein said triggering lever (4) is in the area of its pivot point (40) furnished with a suitable seat (45), which is adjusted for resting of a transmission lever (5) of the interrupting mechanism, and wherein said interrupting mechanism, via which on the one hand by pivoting of the control lever (3) and consequently also by rotating the contactor shaft (2) said electric conductors (101’, 101 ”, 101”’) are connectable, or via which on the other hand on the basis of an impulse from the side of the triggering means on the Fl-relay (44) and rotation of the contactor shaft in the opposite direction electric conductors (101’, 101”, 101’”) are interruptible, is conceived in such a manner i) that said control lever (3) and said contactor shaft (2) are mechanically connected with each other in such a manner, that a further pivot point (32) is arranged on said control handle (3) at a distance apart from said pivot point (30) of the control lever (3) as such in a direction away from the control button (31), namely within the interior of the casing (1), and a rigid primary arm (33) is attached with its first terminal portion (33’) to the control handle (3) in this further pivot point (32), the second terminal portion (33”) of which is in a pivot point (35) pivotally connected with the first terminal portion (34’) of the secondary arm (34), which is in a pivot point (24) arranged in the area of its second terminal portion (34”) pivotally attached to said control arm (22) of the contactor shaft (2); ii) that a two-arm transmission lever (5) is pivotally embedded in its pivot point (50) within the casing (1), the primary arm (51) of which is on its terminal area (510) furnished with a seat (515), which is adjusted for resting on said seat (45) on the triggering lever (4) as long as the triggering lever (4) is maintained in its non-pivoted position prior to activation of the Fl-relay (44), while upon activation of the Fl-relay (44) and pivoting the triggering lever (4) at a sufficient angle by simultaneously changing position of said seat (45), said primary arm (51) of the transmission lever (4) is disengaged from resting on said seat (45) on the triggering lever (4) and is during pivoting around its pivot point (50) freely displaceable across the pivot point (40) of the triggering lever (4), while the secondary arm (52) of the transmission lever (5) which is adjusted to be rest on the control arm (22) of the contactor shaft (2); iii) that the first attachment point (56) of a transmission spring (6) is arranged on said primary arm (51) of the transmission lever (5) in the area between said seat (515) on the terminal area (510) and said pivot point thereof, while the second attachment point (26) of said spring (6) is arranged on the control arm (22) of the contactor shaft (2); iv) that a two-arm arresting lever (7) is pivotally attached to said transmission lever (5) in a further pivot point (57) arranged in the central region thereof and adjacent to the pivot point (50) of the transmission lever (5) as such, wherein the primary arm (71) of the arresting lever (7) extends in a direction towards the pivot point (35) between the primary arm (33) and the secondary arm (34) of the control lever (3), while the secondary arm (72) of the arresting lever (7) protrudes in a direction substantially towards the triggering lever (4), wherein an arresting recess (710) is arranged on said primary arm (71), into which said pivot point (35) between the arms (33, 34) of the control lever (3) is insertable, so that said primary arm (71) is permanently maintained in contact with said pivot point (35) between both control lever arms (33, 34), and said arresting lever (7) as such permanently follows each changes of position of said pivot point (35) by pivoting of the control lever (3) and by displacing of the primary arm (33) and the secondary arm (34) thereof, and wherein an attachment point (78) of a retaining spring (8) is arranged on the secondary arm (72) of the arresting lever (7), while said retaining spring (8) is on the other hand in the other attachment point (48) also attached on the triggering lever (4), so that, whenever said control lever (3) is shifted to its first terminal position, which corresponds to rotation of the control shaft (2) into a position, in which the electric contacts (101 ’, 101”, 101’”) are uninterrupted, the pivot point (32) of the primary arm (33) on the control lever (3) and also the pivot point (35) between the primary and secondary arm (33, 34) of the control lever (3), with which said arresting lever (7) is engaged, are both arranged on the same side of a line, which extends through the pivot point (30) of the control lever (3) and the pivot point (34) of the secondary arm (34) on the control arm (22) of the contactor shaft (2), while on the other hand, whenever said control lever (3) is shifted to its second terminal position, which corresponds to rotation of the control shaft (2) into a position, in which the electric contacts (101’, 101”, 101’”) are interrupted, said coupling of control lever arms (33, 34) is collapsed in such a manner, that, relative to said line through the pivot point (30) of the control lever (3) and the pivot point (24) of the secondary arm (34) of the control lever (3) on the control arm (22) of the contactor shaft (2), said pivot point (35) between the control lever arms (33, 34) is still positioned on the same side of the previously mentioned line, but the pivot point (32) of the primary arm (33) of the control lever (3) is displaced to the other side of said line, wherein such position is despite to said collapsing still stable, since the transmission lever (5) is rest on the control arm (22) of the contactor shaft (2), characterized in that said pivot point (57) of the arresting lever (7) on the transmission lever (5) is arranged in such manner that a rolling member (75) is placed on a cylindrical axle (570), which extends substantially rectangular with respect to the transmission lever (5) and is rigidly connected there-with, wherein said rolling member (75) is loosely and freely rotatably placed on said axle (570) and is secured against undesired removal there-from, and wherein the arresting lever (7) is loosely and freely rotatably placed on the external circumferential surface of said rolling member (75).

2. Switch according to Claim 1, characterized in that said rolling member (75) is uniformly conceived and is on the one of its terminal portions ended by a disc-shaped area (750), the outer diameter of which is larger than the outer diameter of the longitudinal section of the rolling member (75) on which the arresting lever (7) is rest.

3. Switch according to Claim 2, characterized in that said disc-shaped area (750) on the rolling member (75) is, when observed in the longitudinal direction of said cylindrical axle (570), located in the area between the arresting lever (7) and the transmission lever (5).

4. Switch according to anyone of Claims 1 - 3, characterized in that said axle (570) consists of a metallic material and comprises a smooth circumferential surface, and that the rolling member (75) consists of a wear-resistant thermoplastic material with lowest possible friction coefficient by sliding along a smooth metallic surface.

5. Switch according to anyone of Claims 1 - 4, characterized in that said transmission spring (6) is preferably a tension helical spring, which is extendable by manually pivoting of the control handle (3) and consequently pivoting of the transmission lever (5) by simultaneously rotating the contactor shaft (2) towards its first terminal position, in which the electric conductors (101’, 101”, 101”’) are uninterrupted, and is in its extended position capable of accumulating at least such amount of energy, which is sufficient for pivoting of the control lever (3) by simultaneously rotating the contactor shaft (2) into its second terminal position, in which the electric conductors (101 ’, 101 ”, 101 ’”) are interrupted.

6. Switch according to anyone of Claims 1 - 5, characterized in that said retaining spring (8) is preferably a tension helical spring, which is adapted for accumulating of essentially less energy than the transmission spring (6), and which is in its initial position, when the switch has not yet been activated i.e. prior to triggering of the Fl-relay (44), minimally tensioned, namely only in such extent that the triggering lever (4) is maintained in its initial position, which allows the transmission lever (5) to be supported by resting of its seat (515) onto the seat (45) of the triggering lever (4), and the tension in the retaining spring (5) is intensified upon triggering of the Fl-relay (44) and pivoting of the triggering lever (4) during pivoting of the transmission lever (5) with simultaneously pivoting of the control lever (3), so that said intensified tensioning of the retaining spring (8) efficiently supports the arresting lever (7) during its following to changes of position of the control lever (3), namely changes of position of the pivot point (35) between the primary arm (33) and the secondary arm (34) of the control lever (3).

7. Switch according to anyone of Claims 1 - 6, characterized in that said arresting lever (7) is furnished with a further spring (77), which is a torsion spring, the first arm (771) of which is rest on a limiting member (771’) on the secondary arm (72) of the arresting lever (7) adjacent to the attachment point (720) of the retaining spring (8), while the second arm (722) of thereof is rest on the limiting member (772’) on the transmission lever (5).

8. Switch according to anyone of Claim 7, characterized in that said torsion spring (77) is adjusted in such a manner that the control lever (3), which is pivoted by means of energy, which is released from the transmission spring (6), is by means of said torsion spring (77) stopped in its intermediate position between its both terminal positions and regardless to any further rotation of the contactor shaft (2), upon which the control handle (3) is via the control button (31) thereon manually displaceable into each desired terminal position.

9. Switch according to anyone of Claims 1 - 8, characterized in that the pivot point (35) between the primary arm (33) and the secondary arm (34) of the control lever (3) is furnished with a rolling member (350), and that simultaneously the arresting recess (710) on the arresting lever (7) is adjusted for cooperation with said rolling member (350).