Circuit breaker

Abstract

A circuit breaker comprising a containment body containing an actuation mechanism operatively associated with electrical protection components; the actuation mechanism is a self-supporting mechanism comprising a thermal assembly having a movable contact, a plaited band, a bimetal, a terminal and a sliding electrode; the self-supporting mechanism further comprises a kinematic assembly with which the movable contact is associated; an actuation handle is connected to the kinematic assembly by means of a crossbar; two side walls provide the containment of all the components of the self-supporting mechanism.

Description

[0001] The present invention relates to a circuit breaker.

[0002] More particularly, the invention relates to a magnetothermal circuit breaker with a self-supporting mechanism with pre-calibration of the thermal assembly and of the magnetic assembly.

[0003] Magnetothermal electrical circuit breakers use mechanisms that allow to open and close the movable contact both by means of the actuation of an external handle that can be accessed by the user and by means of the automatic tripping of the protection devices provided inside.

[0004] US6750743B1 discloses an integrated thermal and magnetic circuit breaker that includes a cassette associated with each pole in a multi-pole electrical distribution circuit. Each cassette has a housing, a pair of electrical contacts disposed in the housing, and a thermal and magnetic trip unit supported by the housing. The housing has a first compartment having the electrical contacts disposed therein and a second compartment having a portion of the thermal and magnetic trip unit. A wall separates the first and second compartments for isolating the second compartment from gasses generated by separation of the first and second contacts. A duct adjacent to the second compartment allows the gasses to pass to an exterior portion of the housing. The housing has a pair of opposing slots for receiving edges of a load terminal. A lever has a first end disposed proximate an end of a bimetallic element and a second end disposed proximate an armature in the magnetic assembly of the trip unit. The lever is rotated by one of the bimetallic element and the armature to unlatch an operating mechanism.

[0005] GB2286486A discloses a circuit breaker that comprises first and second breaker contacts disposed in a main current path extending between a line terminal and a load terminal. An electromagnetic release device forcibly disengages the second contact from the first contact upon detection of an excess current flowing through the main current path. The release device comprises a coil inserted in the main current path and a plunger magnetically connected to the coil through a yoke which is of a generally U-shaped configuration having a base member and a pair of side members. A pair of opposed first and second arc runners guide an arc, which develops between the breaker contacts upon separation thereof, in a direction away from the breaker contacts. The first arc runner is electrically connected to the first contact and extends away therefrom to give an extension, while the second arc runner is defined by the base member of the yoke. The yoke is electrically connected to the second contact at the side member adjacent to the second contact. The arc runners are confined within a space between opposed side walls of the circuit breaker housing, the width of the space increasing towards the advancing direction of the arc.

[0006] Two constant problems in the design of circuit breakers are the complexity of the mechanisms and the dimensions.

[0007] The need is constantly felt to simplify the mechanisms from the constructive standpoint, in order to render production economical, and in this field it is also very important to achieve an assembly that is simple and can be automated.

[0008] A further fundamental problem is to improve the performance of circuit breakers while maintaining limited dimensions and in any case within standard regulations.

[0009] The aim of the present invention is to provide an electrical device that can be manufactured more economically with respect to traditional ones and at the same time has an improved performance.

[0010] Within the scope of this aim, a particular object of the invention is to provide a modular magnetothermal circuit breaker.

[0011] A further object of the invention is to provide a circuit breaker that can be manufactured with preassembled and pre-calibrated components, by means of automated systems or dedicated production lines.

[0012] A further object of the invention is to provide a circuit breaker that is more reliable in use.

[0013] A further object of the present invention is to provide a structure which, by virtue of its particular constructive characteristics, is capable of giving the greatest assurances of reliability and safety in use.

[0014] This aim and these and other objects which will become better apparent hereinafter are achieved by a circuit breaker as claimed in the appended claims.

[0015] Further characteristics and advantages will become better apparent from the description of preferred but not exclusive embodiments of the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein: Figure 1 is an exploded perspective view of the circuit breaker according to the invention; Figure 2 is a cutout perspective view of the circuit breaker; Figure 3 is a perspective view of the self-supporting mechanism including a thermal relay; Figure 4 is a sectional side view of the circuit breaker, shown after a first assembly; Figure 5 is an enlarged-scale view of the positioning region for post-calibration verification of the bimetal; Figure 6 is a perspective view of the actuation mechanism; Figure 7 is a perspective view of the handle with a crossbar; Figure 8 is a perspective view of the welded thermal assembly.

[0016] With reference to the cited figures, the automatic circuit breaker with self-supporting mechanism, according to an embodiment of the present invention, generally designated by the reference numeral 100, comprises a magnetothermal circuit breaker which includes essentially a containment body 103, which has the classic standardized shape, and forms, at a face 105, means 20 for coupling to an omega-shaped guide (not shown), according to DIN standards.

[0017] The containment body 103 has a protrusion 109 in which the actuation member or actuation handle 9 is positioned.

[0018] The containment body 103 includes a self-supporting mechanism 1, according to the invention, operatively associated with electrical protection components constituted, for example, by a magnetic assembly, which includes a magnetic relay 17, and by a thermal assembly 2 associated with a Dejon cell 18.

[0019] The magnetic relay 17 is associated with a terminal 177 and includes an adjustment spring which is mounted inside the spool, allowing to define the tripping threshold.

[0020] The magnetic assembly does not require adjustments, since the threshold is defined by means of an adjustment spring mounted inside the spool.

[0021] The self-supporting mechanism 1, according to the invention, includes the thermal assembly 2, welded and provided with a movable contact 3, a copper braid 4, a bimetal 5, a terminal or clamp 6, and a sliding electrode 7.

[0022] The self-supporting mechanism also includes a kinematic assembly 8, to which the movable contact 3 is integrally locked.

[0023] The actuation handle 9 is connected to the kinematic assembly 8 by means of a crossbar 10.

[0024] Two side walls 11 and 12 contain all the components of the self-supporting mechanism.

[0025] The self-supporting mechanism includes a pair of arc guide plates 14 and 19 accommodated in the side walls 11 and 12.

[0026] The self-supporting mechanism includes an adjustment grub 13 for the calibration of the thermal relay.

[0027] The upper part of the side wall 12 has a triangular slot 15 for a visual verification of the position of the bimetal 5 for the mechanical calibration of the self-supporting mechanism.

[0028] The automatic circuit breaker according to the invention is assembled and finished by associating the self-supporting mechanism 1 with a base 16 with the components that include, in the specific case, the magnetic relay 17, the Dejon cell 18, the arc guide plate 19, the DIN hook 20, closed by the lid 21 and with trims 22.

[0029] It should be noted that, in addition to the terminal 6 and the screw, other components can already be fitted to the thermal assembly 2; due to their shape, the components can remain assembled without the aid of additional supports.

[0030] In order to reduce the number of components to be assembled at a later time, such as the crossbar 10, the handle 9 with spring and lever for engagement, there are advantageously provided two side walls 11 and 12, which allow to have clearly defined centers in order to reduce both the possibility of error in the subsequent assembly in the base 16 and plays among the various components, improving conveyance and making it impossible for components to be lost.

[0031] The final thermal assembly, with two loadbearing side walls 11 and 12, allows a better rigidity of the thermal assembly and the possibility of a pre-calibration.

[0032] Figure 1 shows the reduced number of components for the final assembly.

[0033] In practice it has been found that the invention achieves the intended aim and objects, providing an automatic circuit breaker which has a self-supporting mechanism that allows a reduced number of components for the final assembly.

[0034] The automatic circuit breaker according to the present invention allows a simple and economical production process by means of preassembled and calibrated components, thus reducing production times and facilitating the management of the production departments.

[0035] The self-supporting mechanism according to the present invention, which can be calibrated and tested prior to the testing of the full product, ensures optimum quality and an increase in the efficiency of the production process.

[0036] The number of the components for the final assembly of the product is considerably reduced, and the same happens to the assembly time and to the risk of error.

[0037] The automation of the assemblies and in particular of the self-supporting mechanism further improves the process.

[0038] The system according to the present invention allows to significantly reduce the number of preassembled components in order to be able to manage the assembly of the product rapidly and stably from the operative point of view and from the point of view of transport.

[0039] The materials used, as well as the dimensions, may be any according to the requirements and the state of the art.

Claims

1. A circuit breaker comprising a containment body (103) containing an actuation mechanism (1) operatively associated with electrical protection components; said containment body (103) comprising a base (16) and a cover; said circuit breaker being characterized in that said actuation mechanism (1) is a self-supporting mechanism comprising a thermal assembly (2) having a movable contact (3), a plaited band (4), a bimetal (5), a terminal (6) and a sliding electrode (7); said self-supporting mechanism (1) further comprising a kinematic assembly (8) associated with said movable contact (3); an actuation handle (9) being connected to said kinematic assembly (8) by means of a crossbar (10); two side walls (11, 12) providing the containment of all the components of said self-supporting mechanism (1), characterised by at least one of said side walls having a slot (15) for visually checking the position of said bimetal (5) for a mechanical calibration of said self-supporting mechanism (1).

2. The circuit breaker according to claim 1, characterized in that said self-supporting mechanism (1) comprises a pair of arc guide plates (14, 19) accommodated in said side walls (11, 12).

3. The circuit breaker according to one or more of the preceding claims, characterized in that said self-supporting mechanism (1) is operatively associated with electrical protection components which comprise a magnetic assembly having a magnetic relay (17), and in that said thermal assembly (2) is associated with a deionization cell (18).

4. The circuit breaker according to claim 3, characterized in that said magnetic relay (17) is associated with a terminal (117) and comprises an adjustable spring fitted inside a spool, allowing to define the action threshold.

5. The circuit breaker according to one or more of the preceding claims, characterized in that said self-supporting mechanism (1) comprises a grub screw (13) for a calibration of the thermal assembly (2).

6. The circuit breaker according to one or more of the preceding claims, characterized in that said containment body (103) forms, at one face (105), means (20) for coupling to an Omega guide according to DIN standards; said containment body (103) having a protrusion (109) in which said actuation handle (9) is arranged.

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