Low-voltage contact group

Abstract

An embodiment of the present disclosure relates to a low-voltage contact set comprising: a fixed contact adapted to be electrically connected to an electrical terminal of a circuit breaker; and a movable contact assembly comprising: a rotary support shaft adapted to be operably connected to an actuation mechanism of the circuit breaker and having a body provided with a first seat; and rotating the moving contact assembly. The rotating moving contact assembly comprises: a support structure positioned on the first seat and rigidly fixed to the rotating support shaft; -a rotating moving contact connected to the support structure by a first pivot and free to rotate relative to the support structure in a plane of rotation substantially perpendicular to the axis of rotation of the rotating support shaft; wherein the rotary moving contact comprises a slender body with a movable surface; -an elastic element adapted to ensure sufficient contact pressure when the movable surface of the moving contact is coupled to the fixed contact, the elastic element having a first operating end and a second operating end; and a mechanical link comprising a first lever and a second lever.

Description

Technical Field

[0001] The present invention relates to a low-voltage contact assembly for a low-voltage switchgear, in particular a low-voltage circuit breaker. More specifically, the present invention relates to a low-voltage contact assembly provided with a rotatable movable contact having optimized performance in the event of contact opening due to repulsive forces, such as under a short-circuit condition. Background Art

[0002] As is known in the low-voltage field, switchgear, in particular circuit breakers, are generally provided with a contact assembly comprising a movable contact and a fixed contact that can be coupled and separated from each other. Low-voltage switchgear of known technology also includes an actuating device that causes relative movement of the movable contact with respect to the fixed contact, so that they can assume at least a first coupled position (closed position - circuit closed) and a second separated position (disconnected position - circuit open).

[0003] It is known in the low-voltage field that for certain applications it is desirable to have sufficient contact pressure between the movable contact and the fixed contact when the movable contact and the fixed contact are in the closed position. To this end, the contact assembly can usually be provided with a system, usually consisting of one or more springs, which act on the movable contact and keep it pressed against the fixed contact.

[0004] It is also known that, under short-circuit conditions, electrodynamic repulsive forces occur between the contacts. These repulsive forces generate a useful thrust that helps increase the separation speed of the movable contact relative to the fixed contact, thereby reducing the intervention time and preventing the presumed short-circuit current from reaching its maximum value.

[0005] A critical aspect in this case is due to the fact that the electrodynamic repulsion force - although actively contributing to contact separation - provides the moving contact with high speed and a lot of energy at the end of its stroke, which may cause a severe impact of the movable contact assembly against the housing of the circuit breaker and may cause the moving contact to bounce towards the fixed contacts.

[0006] In order to properly control the contact pressure in the closed position and the opening speed and energy of the movable contact during repulsion, such as under a short-circuit condition, several solutions have been proposed. For example, relatively complex latching systems have been proposed to prevent the movable contact from bouncing and latch it in the open position; or movable contact assemblies have been proposed in which the movable contact body is specifically contoured so that the torque generated by the compression spring during the rotation of the movable contact can be varied in magnitude and direction, and similar solutions have been proposed.

[0007] However, the known solutions are not entirely satisfactory for many reasons, including for example the mechanical complexity and / or the number of components required, the presence of friction phenomena which may cause wear of the movable contact body, and similar problems. Summary of the Invention

[0008] Based on the above considerations, it is clear that there is a need for available alternative technical solutions that can overcome the above limitations and problems. Therefore, the present disclosure aims to provide a low-voltage contact group, in particular for a low-voltage circuit breaker, which allows to overcome at least some of the above disadvantages.

[0009] In particular, the present invention aims to provide a low voltage contact set, in particular for a low voltage circuit breaker, having improved performance in the event of contact opening due to repulsive forces, for example under short circuit conditions.

[0010] Furthermore, the invention aims to provide a low-voltage contact set, in particular for a low-voltage circuit breaker, which allows avoiding or at least minimizing friction problems caused by electrodynamic repulsion forces between fixed and movable contacts during disconnection.

[0011] Furthermore, the present invention aims to provide a low-voltage contact assembly, in particular for a low-voltage circuit breaker, which has a compact structure.

[0012] Furthermore, the object of the present invention is to provide a low-voltage contact group, in particular for a low-voltage circuit breaker, which is able to ensure sufficient contact pressure between the fixed contact and the movable contact in the closed position without hindering the movement of the movable contact during disconnection due to electrodynamic repulsion forces between the fixed contact and the movable contact, for example under short-circuit conditions.

[0013] Furthermore, the present invention aims to provide a low voltage contact set, in particular for a low voltage circuit breaker, wherein the possibility of a movable contact bouncing towards a fixed contact under a short circuit condition is avoided or at least minimized.

[0014] Furthermore, it is an object of the present invention to provide a low-voltage contact set in which the number of components is minimized.

[0015] Furthermore, an object of the present invention is to provide a low-voltage contact set that is reliable and relatively easy to manufacture at a competitive cost.

[0016] According to the present invention, the above objects and other objects which will become apparent from the following description and accompanying drawings are provided by a low voltage contact set for a low voltage circuit breaker according to the following claim 1 and related dependent claims.

[0017] In another aspect, the present invention also relates to a low voltage circuit breaker, in particular a molded case circuit breaker, comprising a low voltage contact set as described herein.

[0018] In the general definition of the present invention, a low-voltage contact group for a low-voltage circuit breaker is characterized in that the low-voltage contact group comprises:

[0019] - fixed contacts adapted to be electrically connected to electrical terminals of the circuit breaker;

[0020] - A movable contact assembly comprising:

[0021] - a rotary support shaft adapted to be operatively connected to an actuating mechanism of the circuit breaker and having a body provided with a first seat;

[0022] -Rotary moving contact subassembly, including:

[0023] - a support structure positioned at the first seat and rigidly fixed to the rotary support shaft;

[0024] - a rotating movable contact connected to the support structure by a first pivot and freely rotatable relative to the support structure in a rotation plane substantially perpendicular to the rotation axis of the rotating support shaft; wherein the rotating movable contact comprises an elongated body provided with a movable surface, the movable surface being capable of being coupled to / decoupled from the fixed contact by rotation of the movable contact in the rotation plane; wherein the movable surface is positioned at a first operating end of the elongated body and at least partially protrudes from the support structure and from the first seat; wherein the elongated body is connected to the first pivot at an intermediate point between the first operating end and the second operating end of the elongated body;

[0025] - an elastic element adapted to ensure sufficient contact pressure when the movable surface of the movable contact is coupled to the fixed contact, the elastic element having a first operating end and a second operating end, the first operating end of which is connected to the support structure via a second pivot;

[0026] - A mechanical linkage comprising a first lever and a second lever, wherein the first lever has a first operating end and a second operating end, the first operating end of which is connected to the support structure via a third pivot; wherein the second lever has a first operating end and a second operating end, the first operating end of which is connected to the second operating end of the elongated body via a fourth pivot; wherein the second operating ends of the first lever and the second lever are connected to each other via a fifth pivot; and wherein the second operating end of the elastic element is also connected to the fifth pivot.

[0027] For the purposes of the present invention, the terms "first end" and "second end" of a particular component (e.g., the elongated body of a rotating movable contact, a resilient element, a lever of a mechanical linkage) are not meant to designate the physical limits of the associated component, but rather the operating points of the component where a designated function is performed.

[0028] As better explained in the following description, the low-voltage contact set as disclosed herein allows to avoid or at least greatly reduce the above-mentioned problems.

[0029] In practice, as better described below, it has been found that the specific design and structure of the rotary movable contact subassembly provides an effective system for controlling the torque exerted by the elastic element during operation, in particular during the opening movement of the rotary movable contact from the closed and pressed positions to the fully repelled position. At the same time, the elastic element ensures sufficient contact pressure between the movable surface of the rotary movable contact and the fixed contact when the circuit is closed.

[0030] Furthermore, in this way (as better described in the detailed description below), the friction phenomena and the attendant wear problems of certain known solutions can be substantially avoided, since the lever forming the mechanical connection between the elastic element, the support structure and the elongated body of the rotating movable contact is substantially frictionless.

[0031] It must also be noted that, by appropriately designing the lever of the mechanical linkage, it is possible to optimize the distribution of the torque exerted by the elastic element on the rotating movable contact during the disconnection operation under repulsion. In particular, when necessary, the direction of the torque exerted by the elastic element on the rotating movable contact can be reversed at a certain point in the disconnection operation, so that, in the fully repulsive position, the movable contact remains in the disconnected position, preventing it from bouncing towards the fixed contact and possible restriking of the arc.

[0032] At the same time, the relatively simple design of the mechanical linkage allows a very compact overall design of the movable contact assembly to be obtained, thereby reducing the space required to accommodate the contact set in the housing of the low-voltage circuit breaker.

[0033] In typical embodiments of the low-voltage contact set according to the invention, the support structure of the rotary movable contact subassembly may advantageously comprise a first side wall and a second side wall which are substantially parallel to each other and to the rotation plane of the rotary movable contact.

[0034] In this case, in certain embodiments of the presently disclosed low-voltage contact set, the elongated body of the rotary movable contact and the elastic element may advantageously be at least partially housed in the inner volume defined by the first and second side walls.

[0035] Furthermore, in a typical embodiment of the low-voltage contact group, which will be better described in the detailed description below, the first operating end of the first lever can be connected to the first side surface via a third pivot. The mechanical linkage of the rotating movable contact subassembly can then include a third lever and a fourth lever. The third lever can advantageously be provided with a first operating end connected to the second lateral surface via a third pivot and provided with a second operating end; at the same time, the fourth lever can advantageously be provided with a first operating end and a second operating end, the first operating end being connected to the second operating end of the elongated body via a fourth pivot; furthermore, in this embodiment of the invention, the second operating ends of the third and fourth levers can advantageously be connected to each other and to the second operating ends of the first and second levers via a fifth pivot, while the second and fourth levers can advantageously be connected to the second operating ends of the elongated body on opposite sides of the elongated body.

[0036] In a general embodiment of the low-voltage contact set according to the invention, the first, second, third, fourth and fifth pivot axes are preferably substantially perpendicular to the rotation plane of the rotary movable contact.

[0037] In a preferred embodiment of the low-voltage contact set according to the present invention, the first lever and the second lever have a curved profile.

[0038] For example, in an exemplary embodiment of the low-voltage contact set of the present invention, the first lever and the second lever may advantageously have a concavity directed toward the first operating end of the elastic element.

[0039] In an embodiment of the low-voltage contact set according to the present invention, the elastic element of the rotating movable contact subassembly may include, for example, a spring. However, other elastic components that perform the function of a spring may be used.

[0040] In an embodiment of the low-voltage contact set according to the invention, the elongated body of the rotary movable contact is typically movable relative to the support structure between a contact position and a repelling position.

[0041] In this case, as better described below, the torque generated by the elastic element of the rotating movable contact subassembly advantageously opposes the rotation of the elongated body from the contact position to the repulsive position, at least during the initial phase of rotation.

[0042] In particular, the torque generated by the elastic element during rotation of the elongated body from the contact position to the repulsion position may preferably be reduced.

[0043] In a particular embodiment of the low voltage contact set according to the invention, the fourth pivot axis preferably does not intersect the axis between the first and fifth pivot axes during rotation of the elongated body of the rotary movable contact from the contact position to the repulsive position.

[0044] In another specific embodiment of the low-voltage contact group according to the present invention, the torque generated by the elastic element of the rotating moving contact subassembly can counteract the rotation of the slender body of the rotating moving contact from the contact position to the repulsion position at least during the initial stage of rotation, and can assist the rotation of the slender body from the contact position to the repulsion position during the final stage of rotation.

[0045] In fact, according to this embodiment, in the fully repelled position, the movable contact is held in the open position, preventing it from bouncing towards the fixed contact and preventing a reclosing of the contacts that could restrike the arc.

[0046] In particular, in an embodiment of the low voltage contact set of the present invention, the fourth pivot axis preferably intersects the axis between the first and fifth pivot axes during rotation of the elongated body from the contact position to the repulsive position.

[0047] In another aspect, the present invention also relates to a low voltage circuit breaker, in particular a molded case circuit breaker, comprising the low voltage contact set as disclosed herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Other features and advantages of the present invention will become more apparent from the following description of a preferred but not exclusive embodiment of a low-voltage contact group according to the present invention, illustrated by way of example in the accompanying drawings, in which:

[0049] Figure 1 is a perspective view of a low voltage circuit breaker according to the present invention, particularly a molded case circuit breaker;

[0050] Figure 2 yes Figure 1 Exploded view of a molded case circuit breaker shown;

[0051] Figure 3 yes Figure 1 An exploded view of some details of a molded case circuit breaker is shown, illustrating a low voltage contact set according to the present invention;

[0052] Figure 4 is an exploded view of a movable contact assembly of a low-voltage contact group according to the present invention;

[0053] Figure 5 is a perspective view of a rotary movable contact subassembly of a movable contact assembly of a low-voltage contact group according to the present invention;

[0054] Figure 6 yes Figure 5 An exploded view of the rotary moving contact subassembly is shown;

[0055] Figure 7 yes Figure 5 A cross-sectional view of the rotary moving contact subassembly shown in ;

[0056] Figure 8ais a cross-sectional view of a first embodiment of a low-voltage contact group according to the present invention, showing the contact group in an open position;

[0057] Figure 8b is a cross-sectional view of a first embodiment of a low-voltage contact group according to the present invention, showing the contacts first approaching a closed position;

[0058] Figure 8c is a cross-sectional view of a first embodiment of a low-voltage contact group according to the present invention, showing contact and pressed positions (closed and pressed positions);

[0059] Figure 8d is a cross-sectional view of a first embodiment of a low-voltage contact set according to the present invention, showing a fully repelled position;

[0060] Figure 9a is a cross-sectional view of a second embodiment of a low-voltage contact group according to the present invention, showing an open position;

[0061] Figure 9b is a cross-sectional view of a second embodiment of a low-voltage contact group according to the present invention, showing the contacts first approaching a closed position;

[0062] Figure 9c is a cross-sectional view of a second embodiment of a low-voltage contact group according to the present invention, showing contact and pressed positions (closed and pressed positions);

[0063] - Figure 9d is a cross-sectional view of a second embodiment of a low-voltage contact set according to the present invention, showing a fully repelled position;

[0064] Figure 10 is a graph of the torque acting on the movable contact assembly as a function of rotation angle during movement from the closed position to the fully repelled position. DETAILED DESCRIPTION

[0065] With reference to the accompanying drawings, Figure 1 and 2 , an example of a low-voltage circuit breaker 100 is shown, in this case a three-pole molded case circuit breaker 100. According to a general embodiment and according to known solutions, the molded case circuit breaker 100 comprises a housing 104 divided into two parts 105 and 106 that are coupled together. The molded case circuit breaker 100 also comprises a front plate 103 and an operating handle 107.

[0066] For each pole, according to known solutions, a first electrical terminal 101 connected to the fixed contact 2 and a second electrical terminal 110 connected to the moving contact 3 protrude from the housing 104 for connection of the circuit breaker with eg lines and loads.

[0067] For details, see also Figure 3-7The molded case circuit breaker 100 includes a contact set 1 which, in the illustrated embodiment, is formed of a fixed contact 2 and a movable contact assembly 3 electrically connected to an electrical terminal 101 of the molded case circuit breaker 100 .

[0068] In turn, the movable contact assembly 3 includes a rotationally supported shaft 4 operatively connected to an actuating mechanism 102 of a molded case circuit breaker 100, which is housed in a housing 106 and operatively connected to an operating handle 107. The design and operating principle of the actuating mechanism 102 may be those typically used in such circuit breakers, and therefore will not be described in further detail.

[0069] The rotary support shaft 4 has a body 41 provided with a first seat 42 in which the rotary movable contact subassembly 5 is positioned.

[0070] In the illustrated embodiment, the rotary movable contact subassembly 5 comprises a support structure 6 , a rotary movable contact 7 , an elastic element 8 and a mechanical link 9 .

[0071] In particular, the support structure 6 is positioned in the first seat 42 and rigidly fixed to the rotary support shaft 4 so as to follow it in its rotational movement between the different operating positions. The fixing of the support structure 6 in the first seat 42 can be achieved, for example, by using pins 47 positioned transversely relative to the support structure 6 and the side walls of the first seat 42.

[0072] The rotary movable contact subassembly 5 further comprises a rotary movable contact 7 connected to the support structure 6 by a first pivot 51 and freely rotatable relative to the support structure 6 in a rotation plane substantially perpendicular to the rotation axis 43 of the rotary support shaft 4 .

[0073] As shown in the accompanying drawings, the rotating moving contact 7 includes a slender body 71 provided with a movable (contact) surface 72, which is positioned at the first operating end 711 of the slender body 71 and at least partially protrudes from the support structure 6 and the first seat 42, so that the moving contact 7 can be connected to / separated from the fixed contact 2 by rotating the moving contact 7 in the above-mentioned rotation plane.

[0074] The elongated body 71 of the rotary movable contact 7 is electrically connected to a second electrical terminal 110 of the circuit breaker 100 by conventional means, such as a conductive braid 79 .

[0075] Furthermore, the elongated body 71 of the rotary movable contact 7 is mechanically connected to the support structure 6 at a point midway between its first 711 and second 712 operating ends by means of the aforementioned first pivot 51 , as better defined below.

[0076] The rotating movable contact subassembly 5 further comprises an elastic element 8, the purpose of which is to ensure sufficient contact pressure when the movable (contact) surface 72 of the movable contact 7 is coupled to the corresponding fixed contact 2. From a design point of view, the elastic element 8 has a first operating end 81 and a second operating end 82, the first operating end 81 being connected to the support structure 6 via the second pivot 52 and the second operating end 82 being connected to the mechanical link 9 via another pivot, as better described below.

[0077] Furthermore, the rotary movable contact subassembly 5 includes a mechanical link 9 , which in turn includes a first lever 91 and a second lever 92 .

[0078] Specifically, the first lever 91 has a first operating end 911 connected to the support structure 6 via a third pivot 53, and a second operating end 912 operably connected to the second lever 92; the second lever 92 has a first operating end 921 and a second operating end 922, the first operating end 921 is connected to the second operating end 712 of the slender body 71 via a fourth pivot 54, and the second operating end 922 is connected to the second operating end 912 of the first lever 91 via a fifth pivot 55.

[0079] The fifth pivot 55 is also the point at which the elastic element 8 is connected to the moving chain 9. In fact, when the first operating end 81 is fixed to the support structure 6 via the second pivot 52, its second operating end 82 is connected to the moving chain 9 via the fifth pivot 55, thereby achieving an elastic connection between the support structure 6 and the moving chain 9, and therefore an elastic connection with the rotating movable contact 7.

[0080] The present invention Figures 8a-8d 9a-9d describe the functions of the low-voltage contact group 1 of the present invention.

[0081] from Figure 8a and 9a Starting from the open position, the contact system is brought into the closed position by rotating the support shaft 4 counterclockwise. During the first phase of the movement ( Figures 8a-8b and 9a-9b), the entire rotating moving contact subassembly 5 follows the rotation of the rotating support shaft 4 until it reaches Figure 8b and 9b closed position.

[0082] In the second phase of the movement ( Figures 8b-8c and 9b-9c), the rotating support shaft 4 continues its counterclockwise movement, followed by the support structure 6 rigidly fixed thereto, while the elongated body 71 of the rotating movable contact 7 remains stationary, while the active (contact) surface 72 rests on the corresponding fixed contact 2. Due to the action of the elastic means 8, Figure 8c and 9cThe movable contact 7 is brought into its final closed and pressed position, thereby ensuring the required contact pressure between the movable (contact) surface 72 of the rotary movable contact 7 and the corresponding fixed contact 2.

[0083] When the electrodynamic repulsive force appears between the fixed contact 2 and the movable contact 3, the elongated body 71 of the rotating movable contact 7 moves clockwise until it reaches Figure 8d and 9d During this movement, the torque applied by the elastic element 8 on the rotating movable contact 7 follows Figure 10 The path shown leads to the mobile chain 9, where line 200 indicates Figures 8a-8d In the embodiment, line 300 represents Figures 9a-9d Example of .

[0084] In other words, as clearly shown in the accompanying drawings, in the disconnected position ( Figure 8a and 9a ) and closed position ( Figure 8b and 9b ), the elongated body 71 of the rotating movable contact 7 follows the movement of the support structure 6 and the rotating support shaft 4, remaining fixed against the fixed contact 2, while the rotating support shaft 4 and the support structure 6 continue their movement to the closed and pressed position ( Figure 8c and 9c ), and in the contact position and the completely repelled position ( Figure 8d and 9d ) is movable relative to the support structure 6 and the rotating support shaft 4.

[0085] Typically, the mechanical connection between the rotating moving contact 7 and the supporting structure can be schematically represented by segments 930, 940 and 710, which are sequentially hinged and freely rotate relative to each other corresponding to pivots 54 and 55, and the sequential ends of segments 930, 940 and 710 are fixed freely rotating around pivots 51 and 53.

[0086] The intermediate pivot 55 is also the intermediate point of the sequence of segments 930, 940 and 710, where the second operating end 82 of the elastic element 8 is connected to the moving chain 9, thereby providing the required contact pressure in the closed and pressed positions (e.g. Figure 10 0° of the rotating moving contact 7) and during the movement from the contact position to the fully repelling position (as shown in FIG. Figure 10 A torque is generated on the elongated body 71 between a rotation angle of 0° and approximately 55° of the rotating moving contact 7 as shown in the figures.

[0087] In fact, in the embodiment shown, the force exerted by the elastic element 8 is applied linearly on the mobile chain 9 corresponding to the fifth pivot 55 in the direction defined by the second pivot 52 and the fifth pivot 55 so as to provide the required contact pressure and torque.

[0088] One of the advantages of the low-voltage contact set 1 of the present invention is that it is substantially free from the friction problems that affect some known embodiments.

[0089] Furthermore, the combination of the elastic element 8 and the mechanical linkage 9 based on a lever system allows the performance of the low-voltage contact set 1 to be easily adjusted according to operational needs.

[0090] In fact, by appropriately selecting the shape and length of the first lever 91 and the second lever 92, the strength of the elastic element 8, and the relative positioning of the various pivots 51, 52, 53, 54 and 55, such a low-voltage contact group 1 can be designed, in which the torque applied around the rotating movable contact 3 follows the desired behavior.

[0091] Usually, such as Figure 10 As shown in the figure, at least during the initial stage of the above-mentioned rotation, the torque generated by the elastic element 8 around the rotating movable contact 3 counteracts the rotation of the slender body 71 of the rotating movable contact 7 from the contact position (0° rotation angle in the embodiment shown) to the fully repelling position (about 55° rotation angle in the embodiment shown).

[0092] In particular, Figure 10 As shown, in a general embodiment of the presently disclosed low-voltage contact set 1 , the torque generated by the elastic element 8 decreases during the rotation of the elongated body 71 from the contact position at a rotation angle of 0° to the repulsive position at a rotation angle of approximately 55°.

[0093] As mentioned above, the shape and length of the levers 91 and 92, the strength of the elastic element 8 and the relative positioning of the various pivots 51, 52, 53, 54 and 55 in the full exclusion position can adjust the torque value and its direction in the full exclusion position as needed.

[0094] Therefore, in Figures 8a-8d In the embodiment of the invention shown, during the rotation of the elongated body 71 from the contact position at a rotation angle of 0° to the repulsion position at a rotation angle of about 55°, the torque generated by the elastic element 8 decreases in value and maintains the same sign, as shown in FIG. Figure 10 As shown in the curve 200 in the graph of FIG.

[0095] In other words, in this type of embodiment, the torque generated by the elastic element 8 decreases throughout the rotation of the elongated body 71 of the rotary movable contact 7 and tends to be always in the same direction (in Figures 8a-8dThe elongated body 71 is rotated in the embodiment shown in the counterclockwise direction), ie the torque generated by the elastic element 8 opposes the rotation of the elongated body 71 during the entire rotational movement from the contact position to the fully repelling position.

[0096] In particular, refer to Figure 8d From a schematic point of view, the mechanical connection between the rotary movable contact 7 and the supporting structure (represented by the aforementioned segments 930, 940 and 710) is designed so that, during the rotation of the elongated body 71 from the contact position to the fully repelled position, the fourth pivot 54 (connecting the segment 710 with the segment 940) does not intersect the axis 150 between the fifth pivot 55 (connecting the segment 940 with the segment 950) and the first pivot 51 (at the end of the segment 710). In other words, during the rotation of the rotary movable contact 7, the elongated body 71 does not “pass” the axis represented by the segment 150 joining the pivot 51 (the center of rotation of the elongated body 71) and the pivot 55 (the point to which the force of the elastic element is applied), and the torque maintains the same sign (i.e., the torque is constant) even if its absolute value decreases. Figure 8d In the embodiment shown, a counterclockwise rotation is imparted to the elongated body 71).

[0097] exist Figures 9a-9d In the alternative embodiment of the invention shown, the torque generated by the elastic element 8 still decreases during the rotation of the elongated body 71 from the contact position (at a rotation angle of 0°) to the repulsive position (at a rotation angle of approximately 55°), but changes sign when the elongated body 71 approaches the fully repulsive position, as shown in FIG. Figure 10 As shown by curve 300 in the figure.

[0098] As in the previous case, in this type of embodiment, the torque generated by the elastic element 8 decreases throughout the rotation of the elongated body 71 of the rotating movable contact 7. However, unlike the previous case, the torque generated by the elastic element 8 opposes the rotation of the elongated body 71 from the contact position to the repulsive position only during the first stage of the above-mentioned rotation (for example, until when the elongated body 71 rotates a few degrees from the fully repulsive position) and then assists the rotation of the elongated body 71 during the final stage of the above-mentioned rotation.

[0099] In other words, in Figures 9a-9d In the embodiment shown, the torque generated by the elastic element 8 tends to rotate the slender body 71 in one direction (i.e., counterclockwise in the embodiment shown), and in the final stage of rotation, rotates the slender body 71 in the opposite direction (i.e., clockwise in the embodiment shown), thereby keeping the slender body 71 of the rotating movable contact 7 latched in the fully repelled position and avoiding reclosing of the contacts.

[0100] In particular, refer to Figure 9dFrom a schematic point of view, the mechanical connection between the rotary movable contact 7 and the supporting structure (represented by the aforementioned segments 930, 940 and 710) is designed so that during the rotation of the elongated body 71 from the contact position to the fully repelled position, the axis 150 between the fourth pivot 54 (connecting the segment 710 with the segment 940) and the fifth pivot 55 (connecting the segment 940 with the segment 950) and the first pivot 51 (at the end of the segment 710) intersects. In other words, during the rotation of the rotary movable contact 7, the elongated body 71 “passes” the axis represented by the segment 150 joining the pivot 51 (the center of rotation of the elongated body 71) and the pivot 55 (the point to which the force of the elastic element is applied), and the torque changes its sign (i.e., in Figure 9d In the embodiment shown, a clockwise rotation is imparted to the elongated body 71 ), thereby preventing reclosing of the contacts.

[0101] Special References Figure 5 and 6 From a structural point of view, in a preferred embodiment of the low-voltage contact group 1 of the present invention, the support structure 6 of the rotating movable contact subassembly 5 advantageously includes a first side wall 61 and a second side wall 62, which are substantially parallel to each other and parallel to the rotation plane of the above-mentioned rotating movable contact 7.

[0102] The first side wall 61 and the second side wall 62 of the support structure 6 are positioned in the first seat 42 of the body 41 of the rotating support shaft 4 and are rigidly fixed thereto by using a pin 47 which is positioned laterally relative to the first side wall 61 and the second side wall 62 of the support structure 6 and the side walls of the first seat 42 of the rotating support shaft 4.

[0103] Especially Figure 4-7 As shown, in this type of embodiment, the elongated body 71 of the rotary movable contact 7 and the elastic element 8 are at least partially housed in an internal volume defined between the first side wall 61 and the second side wall 62 of the support structure 6 .

[0104] refer to Figure 5 and 6 In a particular embodiment of the low-voltage contact set 1 of the present invention, the mechanical linkage 9 comprises two pairs of levers positioned on opposite sides of the elongated body 71 of the rotary movable contact 7 .

[0105] In fact, in addition to the first and second levers 91 , 92 as previously described, the mechanical linkage 9 also comprises a third lever 93 and a fourth lever 94 , which are positioned on opposite sides of the elongated body 71 of the rotary movable contact 7 , mirroring the positions of the first and second levers 91 , 92 .

[0106] In these embodiments, the first operating end 911 of the first lever 91 is connected to the first side surface 61 of the support structure 6 via the third pivot 53, while the third lever 93 has a first operating end 931 connected to the second side surface 62 of the support structure 6 via the same third pivot 53. In other words, by using the same third pivot 53, the first lever 91 and the second lever 92 are connected to the first side surface 61 and the second side surface 62 of the support structure 6, respectively, on opposite sides of the elongated body 71 of the rotary movable contact 7.

[0107] The fourth lever 94 has a first operating end 941, which is connected to the second operating end 712 of the elongated body 71 via the same fourth pivot 54 that connects the first operating end 921 of the second lever 92 to the second operating end 712 of the elongated body 71. In practice, the second lever 92 and the fourth lever 94 are connected to the second operating end 712 of the elongated body 71 of the rotary movable contact 7 on opposite sides of the elongated body 71 using the same fourth pivot 54.

[0108] The third lever 93 has a second operating end 932, and the fourth lever 94 has a second operating end 942, and the second operating end 942 is operatively connected to the second operating end 932 of the third lever 93. In particular, the second operating ends 932 and 942 of the third lever 93 and the fourth lever 94 are connected to each other and to the second operating ends 912 and 922 of the first lever 91 and the second lever 92 via the same fifth pivot 55.

[0109] The fifth pivot 55 is also the point at which the second operating end 82 of the elastic element 8 is connected to the mobile chain 9 , thereby transmitting the required forces to the two pairs of lever systems 91 ; 92 and 93 ; 94 .

[0110] Typically, the first pivot 51 , the second pivot 52 , the third pivot 53 , the fourth pivot 54 and the fifth pivot 55 may be formed by pins of appropriate shapes, which are substantially perpendicular to the rotation plane of the rotary movable contact 7 .

[0111] According to the simple but effective design of the low-voltage contact assembly 1 of the present invention, the elastic element 8 can include a spring. For example, the elastic element 8 can be a linear spring having a first end 81 and a second end 82, the first end 81 being fixed to the support structure 6 via the second pivot 52, for example, to the first side surface 61 and the second side surface 62 of the support structure 6, and the second end 82 being fixed to the moving chain 9 via the fifth pivot 55. In practice, in an embodiment of the general type, the elastic element 8 rotates about the second pivot 52 and acts linearly in the direction defined by the axis connecting the second pivot 52 with the fifth pivot 55, thereby applying the required force at the midpoint of the hinge system schematically represented by the sequence of segments 930, 940 and 710.

[0112] Thus, the value and direction of the torque generated on the rotating movable contact subassembly 5 can be designed by appropriately choosing the length and shape of the levers forming the moving chain 9 , the positions of the pivot points 51 - 55 and the strength of the elastic element 8 .

[0113] For example, in the embodiment of the low-voltage contact set 1 shown in the figures, the first lever 91 and the second lever 92 (and also the third lever 93 and the fourth lever 94 when present) have a curved profile.

[0114] In particular, the aforementioned lever advantageously has a curved profile with a concavity directed towards the first operating end 81 of the elastic element 8 (for example the pivot point 52 ).

[0115] However, other types of designs are possible and can be easily determined by considering a schematic single-line diagram of the hinge system represented by a sequence of segments 930, 940 and 710, to which the force of the elastic element 8 is applied at its midpoint.

[0116] exist Figure 5 and 6 In the embodiment of FIG. 1 , a rotary movable contact subassembly 5 having a single rotary movable contact 7 is shown, while in FIG. Figure 2-4 In FIG, a contact system is shown having a pair of rotary movable contact subassemblies 5 and a corresponding pair of rotary movable contacts 7 for each pole electrically connected in parallel. In practice, the system of the present invention can be used for different types of circuit breakers designed based on different types of interruptions.

[0117] In general, a low-voltage circuit breaker 100 , in particular a molded case circuit breaker, comprising a low-voltage contact set 1 as described herein is also part of the present invention.

[0118] As can be clearly seen from the above, the low-voltage contact group of the present invention allows solving the technical problems previously highlighted.

[0119] Several variations are possible on the low-voltage contact set thus conceived, all falling within the scope of the appended claims. In practice, the materials used and the possible dimensions and shapes may be any, according to requirements and the state of the art.

Claims

1. A low-voltage contact assembly (1) for a low-voltage circuit breaker (100), characterized in that: The low-voltage contact group includes: a fixed contact (2) adapted to be electrically connected to an electrical terminal (101) of the circuit breaker (100); A movable contact assembly (3) comprising: A rotary support shaft (4) adapted to be operatively connected to an actuating mechanism (102) of the circuit breaker (100), wherein the rotary support shaft (4) has a body (41) provided with a first seat (42); The rotating moving contact subassembly (5) comprises: a support structure (6) positioned in the first seat (42) and rigidly fixed to the rotary support shaft (4); a rotating movable contact (7) connected to the support structure (6) via a first pivot (51) and freely rotatable relative to the support structure (6) in a rotation plane substantially perpendicular to the rotation axis (43) of the rotating support shaft (4); wherein the rotating movable contact (7) comprises an elongated body (71) provided with an active surface (72), the active surface (72) being capable of being coupled to / decoupled from the fixed contact (2) by rotation of the movable contact (7) in the rotation plane; wherein the active surface (72) is positioned at a first operating end (711) of the elongated body (71) and at least partially protrudes from the support structure (6) and from the first seat (42); wherein the elongated body (71) is connected to the first pivot (51) at an intermediate point between the first operating end (711) and the second operating end (712) of the elongated body (71); an elastic element (8) adapted to ensure sufficient contact pressure when the movable surface (72) of the movable contact (7) is coupled to the fixed contact (2), the elastic element (8) having a first operating end (81) and a second operating end (82), the first operating end (81) of the elastic element (8) being connected to the support structure (6) via a second pivot (52); A mechanical link (9), comprising a first lever (91) and a second lever (92), wherein the first lever (91) has a first operating end (911) and a second operating end (912), the first operating end (911) of the first lever (91) being connected to the support structure (6) via a third pivot (53); wherein the second lever (92) has a first operating end (921) and a second operating end (922), the first operating end (921) of the second lever (92) being connected to the second operating end (712) of the elongated body (71) via a fourth pivot (54); wherein the second operating end (912) of the first lever (91) and the second operating end (922) of the second lever (92) are connected to each other via a fifth pivot (55); and The second operating end (82) of the elastic element (8) is also connected to the fifth pivot (55).

2. The low-voltage contact group (1) according to claim 1, wherein the support structure (6) includes a first side wall (61) and a second side wall (62), and the first side wall (61) and the second side wall (62) are substantially parallel to each other and parallel to the rotation plane of the rotating movable contact (7).

3. The low-voltage contact group (1) according to claim 2, wherein the slender body (71) of the rotating movable contact (7) and the elastic element (8) are at least partially accommodated in an internal volume defined by the first side wall (61) and the second side wall (62).

4. The low-voltage contact group (1) according to claim 2 or 3, wherein the first operating end (911) of the first lever (91) is connected to the first side surface (61) through the third pivot (53); and the mechanical link (9) includes a third lever (93) and a fourth lever (94); wherein the third lever (93) has a first operating end (931) and a second operating end (932), and the first operating end (931) of the third lever (93) is connected to the second side surface (62) through the third pivot (53); wherein the fourth lever (94) has a first operating end (941) and a second operating end (942), The first operating end (941) of the fourth lever (94) is connected to the second operating end (712) of the elongated body (71) through the fourth pivot (54); wherein the second operating end (932) of the third lever (93) and the second operating end (942) of the fourth lever (94) are connected to each other and to the second operating end (912) of the first lever (91) and the second operating end (922) of the second lever (92) through the fifth pivot (55); and wherein the second lever (92) and the fourth lever (94) are connected to the second operating end (712) of the elongated body (71) on opposite sides of the elongated body (71).

5. A low-voltage contact group (1) according to one or more of the preceding claims, wherein the first pivot (51), the second pivot (52), the third pivot (53), the fourth pivot (54) and the fifth pivot (55) are substantially perpendicular to the rotation plane of the rotating moving contact (7).

6. Low-voltage contact set (1) according to one or more of the preceding claims, wherein said first lever (91) and said second lever (92) have a curved profile.

7. The low-voltage contact assembly (1) according to claim 6, wherein the first lever (91) and the second lever (92) have a concavity directed toward the first operating end (81) of the elastic element (8).

8. Low-voltage contact set (1) according to one or more of the preceding claims, wherein said elastic element (8) comprises a spring.

9. Low-voltage contact set (1) according to one or more of the preceding claims, wherein said elongated body (71) is movable relative to said support structure (6) between a contact position and a repulsive position.

10. The low-voltage contact set (1) according to claim 9, wherein the torque generated by the elastic element (8) opposes the rotation of the elongated body (71) from the contact position to the repelling position at least during an initial stage of the rotation.

11. The low-voltage contact set (1) according to claim 9 or 10, wherein the torque generated by the elastic element (8) decreases during the rotation of the elongated body (71) from the contact position to the repelling position.

12. A low-voltage contact group (1) according to one or more of claims 9 to 11, wherein the torque generated by the elastic element (8) counteracts the rotation of the slender body (71) from the contact position to the repulsion position at least during the initial stage of the rotation, and assists the rotation of the slender body (71) from the contact position to the repulsion position during the final stage of the rotation.

13. A low-voltage contact group (1) according to one or more of claims 9 to 11, wherein during the rotation of the slender body (71) from the contact position to the repulsive position, the fourth pivot (54) does not intersect the axis (150) between the first pivot (51) and the fifth pivot (55).

14. The low voltage contact group (1) according to claim 12, wherein during the rotation of the slender body (71) from the contact position to the repulsive position, the fourth pivot (54) intersects the axis (150) between the first pivot (51) and the fifth pivot (55).

15. A low voltage circuit breaker (100), in particular a molded case circuit breaker, comprising a low voltage contact set (1) according to one or more of the preceding claims.

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