EP4646730A1

EP4646730A1 - Circuit breaker lever

Info

Publication number: EP4646730A1
Application number: EP24706275.5A
Authority: EP
Inventors: Thomas Chyla; Gunnar Lutzke; Friedrich Löbner; Olaf Rehme; Evelyn Luna Fiona REICHE
Original assignee: Siemens Energy Global GmbH and Co KG
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2023-02-20
Filing date: 2024-01-11
Publication date: 2025-11-12
Also published as: WO2024177739A1; GB2627291A; CN120660164A; GB202302358D0

Abstract

A trip lever for a circuit breaker includes a hub, a cam arm extending in a first radial direction away from the hub; and a release arm extending in a second radial direction away from the hub and extending longitudinally along an axial direction of the hub. The cam arm may include comprises a hardened portion at a distal end and the release arm may include an open lattice structure.

Description

CIRCUIT BREAKER LEVER

BACKGROUND

[0001] Circuit breakers are used as switching and safety elements in electrical power supply networks. Circuit breakers guarantee safe shutdown in the event of a short circuit and protect consumers and systems from overload. For example, they protect cables from damage due to excessive heating as a result of too high an electrical current and are designed to automatically switch off the circuit to be monitored in the event of a short circuit or when an overload occurs and thus disconnect it from the line network.

[0002] For circuit breakers there is a requirement that a short-circuit current must be switched off in a given period of time. A typical requirement is that the opening time should be less than twice the frequency of the current. In a 50 Hz network, a target opening time of 40 milliseconds (ms) is needed, must then be made possible, in s 60 Hz network, a target opening time of 33 ms is needed. Accordingly, minimizing a circuit breaker opening is desired.

BRIEF SUMMARY

[0003] In one aspect, a trip lever for a circuit breaker includes a hub, a cam arm extending in a first radial direction away from the hub and a release arm extending in a second radial direction away from the hub and extending longitudinally along an axial direction of the hub.

[0004] The foregoing has outlined the technical features of the present disclosure so that those skilled in the art may better understand the detailed description that follows. Additional features and advantages of the disclosure will be described hereinafter that form the subject of the claims. Those skilled in the art will appreciate that they may readily use the conception and the specific embodiments disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Those skilled in the art will also realize that such equivalent constructions do not depart from the spirit and scope of the disclosure in its broadest form.

[0005] Also, before undertaking the Detailed Description below, it should be understood that various definitions for certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases. While some terms may include a wide variety of embodiments, the appended claims may expressly limit these terms to specific embodiments.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0006] To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

[0007] FIG. 1 illustrates an aspect of the subject matter in accordance with one embodiment. [0008] FIG. 2 illustrates an aspect of the subject matter in accordance with one embodiment.

DETAILED DESCRIPTION

[0009] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in this description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0010] Various technologies that pertain to systems and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout. The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus. It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multiple elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

[0011] Also, it should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms “including,” “having,” and “comprising,” as well as derivatives thereof, mean inclusion without limitation. The singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term “or” is inclusive, meaning and/or, unless the context clearly indicates otherwise. The phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Furthermore, while multiple embodiments or constructions may be described herein, any features, methods, steps, components, etc., described with regard to one embodiment are equally applicable to other embodiments absent a specific statement to the contrary.

[0012] Also, although the terms "first", "second", "third" and so forth may be used herein to refer to various elements, information, functions, or acts, these elements, information, functions, or acts should not be limited by these terms. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act may be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act may be termed a first element, information, function, or act, without departing from the scope of the present disclosure.

[0013] In addition, the term "adjacent to" may mean that an element is relatively near to but not in contact with a further element or that the element is in contact with the further portion, unless the context clearly indicates otherwise. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Terms “about” or “substantially” or like terms are intended to cover variations in a value that are within normal industry manufacturing tolerances for that dimension. If no industry standard is available, a variation of twenty percent would fall within the meaning of these terms unless otherwise stated.

[0014] FIG. 1 shows a graphical representation of a circuit breaker 102 having a tripping mechanism 104 according to an embodiment of the invention. The triggering of a switch-off, or opening, movement of the circuit breaker 102 is carried out in FIG. 1 by an actuator 106. The actuator 106 may include an electromagnetic trigger, such as a solenoid, for outwardly moving an actuator rod 108 when the actuator 106 is energized. The tripping mechanism 104 may include a support element, for example, a trip lever 110, a shift lever 112, an opening spring 114, and a return spring 116. The actuator 106 moves the trip lever 110. A force of the opening spring 114 is supported by the trip lever 110. By rotating the trip lever 110, the force of the tensioned opening spring 114 is released and the opening action is carried out by separating contacts 118. After switching, the actuator 106 and the trip lever 110 may be moved back to their initial position to reliably maintain the force of the opening spring 114 after the next switch-on or resetting of the circuit breaker 102. For the reset of the moving parts of the actuator 106 and the trip lever 110, return spring 116 may be used, which may be preloaded during the release process by the force of the opening spring 114.

[0015] According to the invention, at least one of the moving parts of the circuit breaker 102 is manufactured by means of an additive manufacturing process. In this case, it is particularly advantageous if the moving parts produced by means of the additive manufacturing process are as light as possible and / or have a low moment of inertia, whereby the return spring 116 force may be reduced. This ensures that the moving parts of the actuator 106 and the trip lever 110 can be accelerated strongly in the shortest possible time and that the return spring 116 is also tensioned in front. Advantageously, lighter weight components allow a reduction of the power consumption of the electromagnetic actuator 106. The reduction of the power requirement on the actuator 106 with simultaneously high requirements for the acceleration of the moving parts and preload of the return spring 116 is achieved, for example, by the fact that the tripping stroke can be kept small by means of the moving parts are as light as possible or have a low moment of inertia, such as, by using additively manufactured components.

[0016] In one embodiment of the invention, for example, the force of opening spring 114 may act directly on the switching lever 112 and is held and triggered by the trip lever 110 but is reduced by a lever gear 120 many times over. The full force of the opening spring 114 is then held by trip lever 110 within the lever gear 120. The trip lever 110 must be accelerated by the actuator 106, but the force of the return spring 116 might be lower when the force of the opening spring 114 to the trip lever 110 is reduced by the lever gear 120. In this case the acceleration by the actuator 106 is faster or the power consumption is lower.

[0017] By means, for example, of an additively manufactured movable component of the lever gear 120, it is achieved that the force needed by the opening spring 114 to accelerate the movable component of the lever gear 120 and therefore the force to the trip lever 110 can be lower and the force needed by the return spring 116 is advantageously lessened. The functions of the trip lever 110 and the return spring 116 are nevertheless safely fulfilled and can be greatly accelerated by the actuator 106 with little power. The actuator 106 must force the trip lever 110 against the force of the return spring 116. Therefore, it is advantageous to design this trip lever 110 and the moving parts of the actuator 106 in such a way that they are particularly light or with the smallest possible moment of inertia. This is achieved by components produced using an additive manufacturing process.

[0018] With additive manufacturing processes such as three-dimensional, or 3D, printing, it is possible to provide several methods of optimizing the moving parts in the circuit breaker 102 and in the lever gear 120. As a result, the shortest possible switching times are achieved by the circuit breaker 102 when using the lowest possible tripping power. Due to the use of the previous manufacturing processes, these advantages could not be achieved in some cases. By means of additive manufacturing processes, such as powder bed-based 3D printing using selective laser melting, it is possible to design the components in such a way that the strength properties of the material are used as well as possible at every point. It is no longer necessary to take into account, e.g., the demoldability of castings and forgings, the maximum degree of forming of forgings and the accessibility of the tools for mechanical processing.

[0019] In an embodiment of the invention, the components produced by additive manufacturing process may have structures. By means of structures, for example, the weight of the component can be reduced without the component losing stability. As structures, for example, honeycomb or lattice structures may be provided. But other structural forms can also be provided, whereby the structures are already created during the production of the component.

[0020] In an embodiment of the invention, the component manufactured by means of the additive manufacturing process comprises at least sections of different materials. It is particularly advantageous to use several materials within one component and thus optimally adapt the individual areas of the component to the mechanical requirements. As materials, in particular plastics, synthetic resins, ceramics, carbon materials, graphite materials and / or metal can be used. Depending on the material used, different additive manufacturing processes can be advantageous. The most important techniques are laser beam melting and electron beam melting for metals and laser sintering for polymers, ceramics and metals, stereolithography and digital light processing for liquid synthetic resins and polyjet modeling as well as fused layer modeling for plastics and partly synthetic resins.

[0021] By means of the different materials and the additive manufacturing process, it is possible to produce areas of a component with lower strength requirements and a high influence on the moment of inertia, e.g., a large distance from the axis of rotation, from materials with a low density. In addition, areas with high strength requirements can be specifically limited locally and, for example, made of high-strength metallic materials. For example, these high-strength metallic materials have a high hardness, so that they can also be used for mechanical contact points of the circuit breaker. It is also possible to apply a layer of hard or curable materials at these mechanical contact points, where e.g., rolling elements roll off, which is then subsequently hardened if necessary. Auch it may be provided that the materials are mechanically reworked in order to achieve a high shape accuracy.

[0022] When using different materials, it is particularly advantageous if the areas with the different materials are connected with each other in a form-fitting manner. This can be in an embodiment of the invention, for example, by a toothing, by wedge molds or cones, etc. Depending on the manufacturing technology used, it may also be envisaged that the areas with different materials will merge with each other during production. Both methods can be used to realize structures that cannot be produced with conventional manufacturing processes.

[0023] FIG. 2 illustrates a circuit breaker tripping mechanism 104 that includes a trip lever 110 comprising a hub 202, a cam arm 122 extending in a radial direction away from the hub 202, and a release arm 204 extending in an axial direction away from the hub 202. A longitudinal axis 216 of the release arm 204 may be offset from the hub axis of rotation 206. In an aspect, the release arm 204 may include an open lattice structure 208. As shown in FIG. 1, the actuator 106 may selectively apply a force to the release arm 204 to rotate the hub 202 around a hub axis of rotation 206. The lever gear 120 may be selectively restrained by the cam arm 122 and releasable from the cam arm 122 when the hub 202 is rotated by the force applied to the release arm 204 by the actuator 106.

[0024] In one aspect, the cam arm 122 includes a hardened portion 212 at a distal end 214 configured for resisting a contact stress applied thereto, such as a Hertzian force from a cam portion 124 of shift lever 112. The hardened portion 212 portion may include an end hardness value greater than a cam arm 122 hardness value. The cam arm 122 may also include an intermediate portion beneath the hardened portion 212 having an intermediate hardness value between that of the end hardness value and the cam hardness value. In another aspect, the cam arm 122 hardened portion 212 may include a cold spray coating. In an embodiment, the cold spray coating may include tungsten carbide. In yet another embodiment, the cam arm 122 may include an aluminum alloy, wherein the hardened portion 212 includes an anodization. [0025] In another aspect, the open lattice structure 208 may be configured to define openings e.g., 210, in portions of the release arm 204 away from a hub axis of rotation 206 so as to keep a center of gravity of the lever close to the hub axis of rotation 206. The open lattice structure 208 may further include a plurality of beams 218 interconnected at vertices, e.g., 202a. In another aspect, at least one of the beams 218 may extend diagonally away from the hub 202. Such beam 218 may include an end vertex 220c disposed at its respective end. In yet another aspect, at least one of the vertices may include a surface 226 configured for receiving an end of the actuator rod 108 thereon for transmitting a force applied by the actuator rod 108 at the surface 226 into a rotational force being applied to the hub 202 around its hub axis of rotation 206 to rotate the cam arm 122 away from the cam portion 124 of the shift lever to trigger disconnecting the contact 118.

[0026] In another aspect, the open lattice structure 208 may include a first lattice portion 222 having a pair of crossed beams 218. In yet another aspect, the open lattice structure 208 may include a second lattice portion 224 having a triangular arrangement of beams 218 extending in a longitudinal direction away from an end of the hub 202. In yet another aspect, the beams 218 may include one or more cross section configurations for reduce a weight of one of more of the beam 218 while maintaining a desired stiffness of the release arm 204. For example, the beam 218 may include at least one of an "I"-shaped cross section, a double "T" shaped cross section, a “C” shaped cross section, or an hourglass-shaped cross section.

[0027] To reduce a weight of the trip lever 110, it may include a different material in a lever portion 228 subject to primarily a tension stress, such as along a side of the release arm 204 subject to actuator 106 force, than in a portion subject to primarily compression stress. Advantageously, such different material portions may be manufactured using an additive manufacturing process.

[0028] Although an exemplary embodiment of the present disclosure has been described in detail, those skilled in the art will understand that various changes, substitutions, variations, and improvements disclosed herein may be made without departing from the spirit and scope of the disclosure in its broadest form.

[0029] None of the description in the present application should be read as implying that any particular element, step, act, or function is an essential element, which must be included in the claim scope: the scope of patented subject matter is defined only by the allowed claims. Moreover, none of these claims are intended to invoke a means plus function claim construction unless the exact words "means for" are followed by a participle.

LISTING OF DRAWING ELEMENTS

102 circuit breaker

104 tripping mechanism

106 actuator

108 actuator rod

110 trip lever

112 shift lever

114 opening spring

116 return spring

118 contact

120 lever gear

122 cam arm

124 cam portion

202 hub

204 release arm

206 hub axis of rotation

208 open lattice structure

210a opening b opening c opening hardened portion distal end longitudinal axis beam a vertex b vertex c vertex first lattice portion second lattice portion surface lever portion first radial direction second radial direction axial direction

Claims

CLAIMS What is claimed is:

1. A trip lever for a circuit breaker comprising: a hub; a cam arm extending in a first radial direction away from the hub; and a release arm extending in a second radial direction away from the hub and extending longitudinally along an axial direction of the hub.

2. The lever of claim 1, wherein the cam arm comprises a hardened portion at a distal end having an end hardness value greater than a cam arm hardness value configured for resisting a contact stress applied thereto.

3. The lever of claim 2, further comprising an intermediate portion beneath the hardened portion having an intermediate hardness value between that of the end hardness value and the cam hardness value.

4. The lever of claim 2, wherein the hardened portion comprises a cold spray coating.

5. The lever of claim 4, wherein the cold spray coating comprises tungsten carbide.

6. The lever of claim 2, wherein the cam arm comprises an aluminum alloy wherein the hardened portion comprises an anodization.

7. The lever of claim 1, wherein the release arm comprises a lattice structure comprising a plurality of beams interconnected at vertices, the lattice structure comprising openings in portions of the arm away from a hub axis of rotation to keep a center of gravity of the lever close to the hub axis.

8. The lever of claim 7, where at least two of the vertices are longitudinally aligned relative to the hub axis of rotation.

9. The lever of claim 7, wherein at least one of the vertices comprises a surface configured for receiving an actuator plunger thereon for transmitting a lateral force applied by the actuator at the surface to a rotational force being applied to the hub around its hub axis of rotation.

10. The lever of claim 7, wherein at least one of the beams comprises at least one of an T- shaped cross section, a double "T" shaped cross section, a “C” shaped cross section, or an hourglass-shaped cross section.

11. The lever of claim 7, wherein at least one of the beams extends diagonally away from the hub.

12. The lever of claim 11, wherein at least one of the beams extending diagonally away from the hub comprises an end vertex disposed at its respective end.

13. The lever of claim 9, wherein the open lattice structure comprises a first lattice portion having a pair of crossed beams and a second lattice portion having a triangular arrangement of beams extending in a longitudinal direction away from an end of the hub.

14. The lever of claim 1 , wherein a longitudinal axis of the release arm is offset from the hub axis of rotation.

15. The lever of claim 1 , wherein the lever comprises a different material in a lever portion subject to a tension stress.