Movable contact configured to be integrated into a circuit breaker

Abstract

The subject of the present invention relates to a movable contact configured to be integrated in a circuit breaker and to be supported on a fixed contact in the vicinity of an arc chamber, said movable contact having the form of a plurality of fingers (2) juxtaposed in a substantially parallel manner and aligned with each other and connected by one of their ends (2a) to a common stem, characterized in that the interdigitated space separating the respective surfaces of two juxtaposed fingers (2) of the movable contact has a separation width having a value less than or equal to 1.3 millimeters.

Description

Technical Field

[0001] This invention relates to the field of contact interfaces in the circuit breaking mechanism inside a circuit breaker, and more specifically, to the field of the arrangement of these contact interfaces. Background Technology

[0002] A circuit breaker includes a mechanism for triggering power disconnection in the event of an overload or overvoltage in the circuit on which the circuit breaker is housed. This mechanism uses a pair of contact elements arranged in an arc chamber, which ensures current flow when the elements are connected and prevents electrical continuity between the two contact elements when they are separated. Mechanically, these contact elements comprise, on the one hand, a contact that is stationary relative to the support structure of the circuit breaker, and on the other hand, a contact that is movable relative to the stationary contact. Both the stationary and movable contacts have their own surfaces designed to support each other to ensure current flow. However, it should be remembered that the surface of the movable contact, supported on the surface of the stationary contact, must be large enough to optimize the current passing through the circuit breaker's disconnecting mechanism.

[0003] Typically, a connection between a movable contact and a stationary contact is formed in a structure made of conductive material. This structure has multiple fingers arranged parallel to each other, such that the surface of each finger has a surface designed to support the stationary contact. Unlike a movable contact with a single finger of similar width to the stationary contact, a movable contact with several fingers spaced apart from each other ensures optimal contact surface between the plane of each movable finger and the flat surface of the stationary contact. This eliminates the risk of tilting between the plane of the movable contact formed by a single finger and the plane of the stationary contact, resulting in a support surface smaller than the surfaces of both the stationary and movable contacts. However, if there are too many fingers, the support surface of each finger supporting the stationary contact becomes particularly small, and the pressure applied by the movable contact may cause the ends of these fingers to degrade the surface quality of the stationary contact.

[0004] Furthermore, the movable contact includes separating elements in its interdigital space. These elements are necessary to maintain the parallel orientation of the different fingers of the movable contact relative to each other, thereby ensuring optimal distribution of the support surfaces of the movable contact's fingers supporting the stationary contact. Additionally, the dimensions of the arc chamber forming the volume occupied by the movable contact are also subject to dimensional constraints. These constraints impose maximum values ​​on the length of the movable contact, and in particular on the width of the surface of the movable contact supporting the stationary contact.

[0005] Considering these different constraints—firstly, concerning the dimensions imposed by the arc chamber and the separation element, and secondly, the optimization of the current through the support surface between the moving and stationary contacts—the disconnecting mechanisms developed to date for three-stage circuit breakers are based on a technical compromise: the moving contact comprises up to five fingers with a corresponding width of approximately 6 mm, arranged in parallel and spaced apart from each other by the separation element by a few millimeters. Under these conditions, existing circuit breakers for industrial applications can withstand currents with ICW (short-time withstand current) values ​​up to 50 kA while enduring heating amplitudes of approximately 70 K. However, this level of technical performance of circuit breaker disconnecting mechanisms is often insufficient for the safety requirements and conditions suitable for industrial applications. Summary of the Invention

[0006] The present invention aims to overcome these different drawbacks by proposing a solution that can improve the current that the circuit breaker can withstand while reducing the heating amplitude of its contacts, and at the same time complying with the size constraints of the arc chamber solved by existing devices.

[0007] Therefore, the present invention relates to a movable contact configured to be constructed in a circuit breaker, the movable contact being supported on a stationary contact near an arc chamber, the movable contact having the form of a plurality of substantially parallel juxtaposed fingers, wherein the plurality of fingers are aligned with each other and connected to a common trunk at one end thereof, characterized in that the interdigitated space separating the respective surfaces of two juxtaposed fingers of the movable contact has a gap width of less than or equal to 1.3 mm. Attached Figure Description

[0008] The invention can be better understood from the following description of various preferred embodiments provided as non-limiting examples and explained with reference to the accompanying schematic diagrams, wherein:

[0009] Figure 1 This is a schematic diagram of an exemplary arrangement of the movable contact according to the present invention.

[0010] Figure 2 This is a schematic exploded view of an exemplary arrangement of the movable contacts according to the present invention.

[0011] Figure 3 This is a schematic diagram of an exemplary finger-like structure including a movable contact with a separating element according to the present invention.

[0012] Figure 4 This is a schematic diagram of an exemplary finger-separating element of a movable contact according to the present invention. Detailed Implementation

[0013] The present invention relates to a movable contact 1 configured to be constructed in a circuit breaker, the movable contact being supported on a stationary contact near an arc chamber, the movable contact having the form of a plurality of substantially parallel juxtaposed fingers 2, wherein the plurality of fingers 2 are aligned with each other and connected to a common trunk 2b at one end 2a, characterized in that the interdigitated space 3 separating the respective surfaces of two juxtaposed fingers 2 of the movable contact 1 has a gap width of less than or equal to 1.3 mm.

[0014] The construction of this movable contact 1 according to the invention incorporates the arrangement of its various fingers 2, such that their respective positioning close to each other frees up sufficient space in the width of the arc chamber, allowing for additional fingers 2 compared to movable contacts in the prior art. The presence of these additional fingers 2 optimizes the surface of the movable contact 1 supported on the surface of the stationary contact. Furthermore, while movable contacts known in the prior art include five fingers 2 supported on the surface of the stationary contact, the presence of a sixth finger 2 in the movable contact according to the invention increases the total exchange cross-section between the movable and stationary contacts. This approach first increases the ICW value of the circuit breaker and secondly reduces the heat experienced by the circuit breaker without affecting the size of the arc chamber.

[0015] According to a construction variation associated with a specific example of the movable contact according to the invention, the movable contact 1 includes at least six contact fingers 2, each of which is associated with at least one separating element 4 positioned in an interdigital space 3. The at least one separating element separates two juxtaposed fingers 2, and the separating element 4 has a size greater than or equal to 70 × 10⁻⁶. -8 The resistivity is measured in Ω·m (ohm-meter). According to an exemplary embodiment, the separating element 4 is made of stainless steel. This arrangement with the separating element 4 provides rigidity to the pair of fingers 2 arranged on either side of the interdigital space 3, limiting the risk of deformation of the fingers 2 and the risk of contact between the two juxtaposed fingers 2 if at least one of the fingers deforms.

[0016] According to a specific exemplary configuration, each of the six fingers 2 of the movable contact 1 has a width of approximately 6 mm, wherein the intervals separated by the interdigitated spaces 3 are approximately 1.2 mm. Therefore, this configuration allows the movable contact 1, including the six fingers 2, to be positioned within an arc chamber having a width of approximately 46 mm. Thus, this particular arrangement of the movable contact 1 with six fingers 2 is a preferred embodiment in which, within a 46 mm wide arc chamber—that is, in a circuit breaker allocating a volume of 70 mm to position a pair of movable and stationary contacts—the number of contact fingers 2 of said size optimizes a combination of two aspects: on the one hand, resistance to the current applied to the circuit breaker; on the other hand, limiting the heating of its contacts.

[0017] According to another specific example of the movable contact of the present invention, a different construction variation can be combined with the aforementioned variation, in which the juxtaposed different fingers 2 of the movable contact 1 have substantially the same dimensions in a cross-section at least in a plane perpendicular to the principal axis of the fingers 2. These identical cross-sections increase the exchange surface by 20% compared to the total exchange cross-section between the stationary and movable contacts in the prior art, which includes five fingers 2. This arrangement improves the performance between the movable and stationary contacts, enabling the circuit breaker to achieve an ICW value of 55 kA and a heating temperature reduction of 5 K compared to known devices in the prior art.

[0018] According to another construction variation associated with a specific example of the movable contact 1 of the present invention, which can be combined with the aforementioned variation, the juxtaposed different fingers 2 of the movable contact 1 have substantially the same dimensions in cross-section at least in a plane perpendicular to the principal axis of the fingers 2. This similarity in shape and construction between the different fingers 2 allows the current moving through the movable contact 1 to be distributed similarly or identically among the different fingers 2. The stress applied to each finger 2 is also the same, thereby facilitating the optimization of the performance of the movable contact 1.

[0019] In another construction variation of the movable contact 1 according to the invention, which can be combined with the aforementioned variation, in the interdigital space 3, the surface 2a of each of the two juxtaposed contact fingers 2 is associated with a corresponding separating element 4. This arrangement of the pair of separating elements 4 in each interdigital space 3 allows one separating element 4 to move relative to the other by friction between the corresponding surfaces in the interdigital space 3. Furthermore, positioning the pair of separating elements 4 in the interdigital space 3 enables double insulation, including thermal and electrical insulation, between the two juxtaposed fingers.

[0020] According to another construction variation related to a specific example of a construction variation of the separating element 4, each separating element 4 is fixedly mounted to a corresponding finger 2 such that each separating element 4 is able to rub against the surface of its corresponding finger 2. According to this specific variation, the interdigital space 3 includes separating elements 4 associated with the corresponding fingers 2 of the movable contact 1, such that movement of one of the fingers of the movable contact 1 relative to its juxtaposed adjacent finger occurs by sliding between the surfaces of the respective separating elements 4 associated with each of the respective fingers 2 surrounding the interdigital space 3.

[0021] According to another specific example of a construction variation of the separating element 4, which can be combined with the foregoing example, at least one separating element 4, made of stainless steel, has a rider arrangement in a cross-section in a plane perpendicular to the main axis of the finger 2. This rider arrangement is designed to insert against the interdigitated surfaces 2a of the finger 2, such that the legs are located on two opposing surfaces 2a of the finger 2, which share a common edge with the interdigitated surfaces 2a. This rider arrangement of the separating element 4 allows several surfaces of the finger 2 to have thermal and electrical insulation. Furthermore, this rider arrangement of the separating element 4 facilitates the installation and assembly of the separating element 4 with the dedicated fingers 2 of the movable contact 1 by inserting the fingers 2 between the respective legs of the separating element 4. According to a specific variant embodiment, a snap-fit ​​mechanism with a clamping function is used to position the separating element 4 on the finger 2.

[0022] According to another specific example of a construction variation of the separating element 4, which can be combined with the foregoing example, at least one separating element 4 made of stainless steel has a straddle arrangement in a cross-section in a plane perpendicular to the main axis of the finger 2, in which the legs are arranged to at least cover a large portion of the interdigital surfaces 2a located on both sides of a given finger 2. This arrangement of the separating element 4 makes it possible to cover a significant or substantial portion of the side surfaces 2a of the finger 2 positioned to face the respective finger. Furthermore, the characterized separating element 4 enables the provision of thermal and electrical insulation between two juxtaposed fingers along a significant portion of the interdigital space 3.

[0023] According to another specific example of a construction variation of the separating element 4, which can be combined with the foregoing example, at least one edge of one of the legs of the straddle of the separating element 4 has a retaining device 41 positioned against one of the faces of the fingers 2, which shares a common edge with the interdigital surface 2a covered by the legs of the separating element 4. According to the exemplary configuration, the retaining device 41 is arranged to engage with one of the faces of each finger 2 to limit or prevent the surface of the legs of the separating element 4 from sliding relative to the interdigital surface of the fingers 2 supported by the separating element 4. The retaining device 41 may be a lug formed as a material extension of the legs of the separating element 4 and curved into a plane substantially parallel to the portion of the straddle connecting the two legs. According to a specific exemplary configuration, the relative flexibility of the legs of the straddle member relative to the connecting portion allows the straddle member of the separating element 4 to be inserted onto the finger 2 until the lug of the retaining device 41 engages with the surface of the finger 2, which is opposite to the surface of the finger 2 that interacts with the portion of the straddle member that forms a connection between the two legs of the separating element 4. Then, using the legs of the separating element 4, the insertion of the straddle member of the separating element 4 onto the finger 2 clamps the finger 2.

[0024] According to another specific example of the construction variation of the separating element 4, which can be combined with the foregoing example, at least a portion of the interdigitated surface of the separating element 4 positioned against the fingers has a thickness of less than or equal to 0.7 mm, preferably about 0.6 mm.

[0025] According to another specific example of a construction variation of the separating element 4, which can be combined with the foregoing example, at least one separating element 4 includes a spring device designed to separate two juxtaposed separating elements. According to a first exemplary construction of this spring device, the spring device includes at least one relief on one of the surfaces of the separating element 4 for positioning against or within the interdigital space of the fingers. The relief may be a boss that causes a moderate variation in the flatness of the surface of the separating element 4 relative to the plane of the interdigital surface, such that the curvature of the boss separates a portion of the surface of the separating element 4 from the remainder of the surface of the separating element supported on the interdigital surface of the fingers 2. Due to the elasticity of the material of the separating element 4, the curvature of the boss allows for a degree of deformability, thereby forming a spring device similar to a Belleville washer constructed in a portion of the separating element 4. According to a second exemplary embodiment, the spring device is provided by a Belleville washer associated with the surface portion of the separating element 4 located in the interdigital space.

[0026] According to another specific example of a construction variation of the separating element 4, which can be combined with the foregoing example, at least one surface of the separating element 4 supporting the interdigital surface of the finger 2 has substantially the same shape and size as the surface of the interdigital surface of the finger 2 against which the separating element 4 rests. This surface similarity enables optimized support contact between the separating element 4 and the interdigital surface of the finger 2, thereby keeping the finger 2 of the movable contact 1 oriented along its axis for as long a portion as possible.

[0027] According to a specific example of the movable contact 1 of the invention, another construction variation, which can be combined with the above-described variation, involves the movable contact 1 being associated with a straight pivot through-pin 5, wherein the straight pivot through-pin 5 is mounted in through-holes 10, 14 in each finger 2 of the movable contact 1 and the associated separating element 4. The straight pivot through-pin 5 defines the pivot axis of each finger 2 of the movable contact 1 and, in operation, serves to separate the movable contact 1 from the stationary contact in the event of an electrical overload or overvoltage in a circuit comprising a circuit breaker having movable and stationary contacts. According to an exemplary arrangement, each finger of the movable contact 1 is associated with a separating element 4 comprising one or more spring devices, the through-holes 14 being centered within these spring devices. For example, when the spring assembly takes the form of a curved boss, the through hole 14 is centered on the boss, making the arrangement of the boss look similar to a Bellwell spring washer, which is constructed in a part of the separating element 4 and passed through by a straight pivot pin 5.

[0028] According to another construction variation related to a specific example of the movable contact 1 according to the invention, the movable contact 1 further includes at least one separator 40 made of stainless steel, which is positioned against a surface opposite the interdigitated surface of the finger 2 at the end of the movable contact 1. The separator 40 is intended to be located at one of the side ends of the movable contact 1, against the side surfaces of the finger 2 of the movable contact 1 that are at the end and are not interdigitated. Therefore, by separating the side surfaces of the finger 2 of the movable contact 1 at the end from the surface of the bearing structure including the circuit-breaking mechanism of the movable contact 1 according to the invention, these separators 40 at the end perform a function similar to the interdigitated separating element 4. It should be noted that the separator 40 located at the side end of the movable contact 1 can be formed by the leg of a straddle member of a separating element 4 mounted on the finger at the end of the movable contact 1.

[0029] Of course, the present invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications can be made to the present invention, particularly in terms of the configuration of different elements or by substitution with technical equivalents, without departing from the scope of protection of the present invention.

Claims

1. A movable contact (1) configured to be constructed in a circuit breaker, the movable contact being supported on a stationary contact near an arc chamber, the movable contact having the form of a plurality of substantially parallel juxtaposed fingers (2) aligned with each other and connected at one end to a common trunk (2b), characterized in that, The interdigitated space (3) separating the respective surfaces of the two juxtaposed fingers (2) of the movable contact (1) has a gap width of less than or equal to 1.3 mm, and on the one hand, in the interdigitated space (3), the surface of each of the two juxtaposed fingers (2) is associated with a corresponding separating element (4), and on the other hand, each of the separating elements (4) is fixedly mounted to the corresponding finger (2) such that each of the separating elements (4) can generate friction with the surface of its corresponding finger.

2. The movable contact (1) according to claim 1, characterized in that, The movable contact (1) includes at least six contact fingers (2), each of which is associated with at least one separating element (4) located in the interdigitated space (3). The at least one separating element separates two juxtaposed fingers (2), and the separating element (4) has a size greater than or equal to 70 × 10⁻⁶. -8 Resistivity in Ω•m (ohm-meter).

3. The movable contact (1) according to claim 1, characterized in that, The juxtaposed different fingers (2) of the movable contact (1) have substantially the same size in a cross section in a plane perpendicular to the principal axis of the fingers (2).

4. The movable contact (1) according to claim 1, characterized in that, At least one separating element (4) made of stainless steel has a straddle arrangement in a cross section in a plane perpendicular to the main axis of the finger (2), the straddle arrangement being designed to be inserted against the interdigital surface of the finger (2) such that the legs are located on two opposing surfaces of the finger (2) having a common edge with the interdigital surface.

5. The movable contact (1) according to claim 1, characterized in that, At least one separating element (4) made of stainless steel has a straddle arrangement in a cross section in a plane perpendicular to the main axis of the finger (2), wherein the legs are arranged to at least cover most of the interdigital surfaces located on both sides of the given finger (2).

6. The movable contact (1) according to claim 4, characterized in that, At least one edge of one of the legs of the straddle of the separating element (4) has a retaining device (41) positioned against one of the surfaces of the finger (2), the surface having a common edge with the interdigital surface covered by the leg of the separating element (4).

7. The movable contact (1) according to claim 1, characterized in that, At least a portion of the separating element (4) positioned against the interdigitated surface of the finger has a thickness of less than or equal to 0.7 mm.

8. The movable contact (1) according to claim 1, characterized in that, At least one separating element (4) includes a spring device designed to separate two juxtaposed separating elements (4).

9. The movable contact (1) according to claim 1, characterized in that, The surface of at least one separating element (4) supported on the interdigital surface of the finger (2) has substantially the same shape and size as the surface of the interdigital surface of the finger (2) to which the separating element (4) is positioned.

10. The movable contact (1) according to claim 1, characterized in that, The movable contact (1) is associated with a straight pivot pin (5), wherein the straight pivot pin (5) is mounted in a through hole (10, 14) in each finger (2) of the movable contact (1) and the associated separating element (4).

11. The movable contact (1) according to claim 1, characterized in that, The movable contact (1) also includes at least one separator (40) made of stainless steel, the at least one separator being positioned against a surface opposite the interdigitated surface of the fingers at the end of the movable contact (1).

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