EP3046132A1

EP3046132A1 - Circuit breaker

Info

Publication number: EP3046132A1
Application number: EP15151253.0A
Authority: EP
Inventors: Felipe de Jesus Chavarria Gonzalez
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2015-01-15
Filing date: 2015-01-15
Publication date: 2016-07-20

Abstract

The present invention relates to a circuit breaker (10), comprising an upper housing element (30), a lower housing element (40) and a trip unit (20) located between the upper housing element (30) and the lower housing element (40), wherein the trip unit (20) comprises a frame element (21), and at least part of an external wall (32) of the upper housing element (30) and at least part of an external wall (42) of the lower housing element (40) are flush with at least part of an external wall (22) of the frame element (21).

Description

The present invention relates to a circuit breaker comprising an upper housing element, a lower housing element and a trip unit located between the upper housing element and the lower housing element.
Existing circuit breakers, for example molded case circuit breakers with an adjustable thermal-magnetic or electronic trip unit, are known as automatically operated electrical switches for protecting an electrical circuit from damage caused by overload or short circuit. In such circuit breakers there is always the challenge of how to provide all the components from different systems like thermal, magnetic and/or latching parts in the housing of said circuit breakers.
In prior art, a circuit breaker is known having a trip unit received in a housing. For example, WO 2007/087762 A1 discloses a thermal-magnetic trip unit for a circuit breaker, in particular a power circuit breaker, having a housing, in which a busbar having at least one bar end passed out of the housing, a current sensor for detecting a current flowing via the busbar, evaluation electronics for identifying an overcurrent and/or short-circuit current, an actuator, which can be controlled by the evaluation electronics, and a transmission lever, which interacts mechanically with the actuator, are arranged together.
In such a circuit breaker, the different components of the trip unit are arranged as compact as possible in order to optimally use the available space therein. Increasing the space in the trip unit by simply increasing the trip unit itself is hardly possible, because it is encompassed or encircled by the housing. Increasing the trip unit and the housing would lead to an enlarged circuit breaker, which is not desired either. Reducing the wall thickness of the trip unit would result in negative dielectric issues and gasses and/or pollution easily leaving the trip unit.
It is an object of the present invention to solve at least part of the above problems. Specifically, it is an object of the present invention to provide a circuit breaker with increased space for internal components while ensuring a minimum wall thickness of the trip unit.
According to one aspect of the present invention a circuit breaker is provided, comprising an upper housing element, a lower housing element and a trip unit located between the upper housing element and the lower housing element, wherein the trip unit comprises a frame element, and at least part of an external wall of the upper housing element and at least part of an external wall of the lower housing element are flush with at least part of an external wall of the frame element.
By providing at least part of an external wall of the frame element flush with at least part of the external wall of the upper housing element and at least part of the external wall of the lower housing element, the space and/or volume in the trip unit can be increased while assuring a required minimum wall thickness to avoid dielectric issues and prevent gasses and/or pollution to leave the circuit breaker during operation.
The trip unit of the present invention is, for example, a thermal-magnetic or electronic trip unit and can be supported by the upper housing element and the lower housing element. In contrast to the known trip units, which are completely inside a housing and/or covered by an upper housing element and a lower housing element, at least part of an external wall of the upper housing element and at least part of an external wall of the lower housing element are flush with at least part of an external wall of the frame element. That is, the external surface of the at least part of the external wall of the upper housing element and the external surface of the at least part of the external wall of the lower housing element are flush with, i.e., on the same level or plane or basically on the same level or plane as the at least part of the external wall of the frame element.
The upper housing element and the lower housing element are preferably two separate elements, but can also be provided as an integral element in one piece. The upper housing element can form an upper part, an upper cover or a part of the upper cover of the circuit breaker. The lower housing element can be designed as a lower part, a bottom or a part of the bottom of the circuit breaker.
According to the present invention, it is preferred that the trip unit is located between the upper housing element and the lower housing element in such a way that the upper housing element and the lower housing element are in direct contact with the trip unit or the frame element thereof. Nevertheless, it is also possible that there are intermediate elements between the upper housing element, the lower housing element and/or the trip unit.
It is further possible in accordance with the present invention that part of the external wall of the frame element is part of at least one protrusion from at least one side face of the frame element. By means of such a protrusion of the frame element the trip unit can be securely arranged between the upper housing element and the lower housing element while the protrusion functions as a latching and/or fitting element. Besides, the required minimum wall thickness of the trip unit can be achieved while also increasing the space and/or volume inside the trip unit. In the present invention it is preferred that the frame element has two protrusions, one each on two opposing side faces in longitudinal direction. The longitudinal direction is, for example, the direction in which the circuit breaker has the greatest length. Alternatively, it is also possible that the frame element has two protrusions on each of two opposing side faces in width direction. Moreover, it is possible that there are more than two protrusions from more than two side faces. For example, it is possible that there is a plurality of protrusions like two, three, four or more on each one of two, three or four side faces of the frame element. While at least part of an external wall of the upper housing element and at least part of an external wall of the lower housing element are flush with at least part of an external wall of the frame element and/or the at least one protrusion, the other part of the external wall of the frame element is preferred to be adjacent or in contact to at least part of the internal wall of the upper housing element and/or at least part of the internal wall of the lower housing element.
In a further example, at least one segment of the protrusion has a z-shape or basically a z-shape in cross-section. With such a shape the protrusion is particularly advantageous in terms of its latching, fitting and/or plugging function. The z-shape is not limited to the shape of the classical letter "Z" having kind of an undercut with two sharp angles. Rather, the shape of the protrusion in cross-section may also comprise a z-shape having two right angles or basically right angles or even two obtuse angles. It is preferred, that the protrusion has not only one z-shape or basically z-shape in cross-section but a plurality, for example two.
According to the present invention it is also of advantage when the upper housing element and the lower housing element are designed and arrangeable such that they form at least one opening between them, wherein the at least one opening has the same shape or basically the same shape as one side, i.e., one end side of the at least one protrusion. This results in the advantageous effect that the trip unit can be arranged easily and securely between the upper housing element and the lower housing element. It is preferred that the upper housing element and the lower housing element are designed and arrangeable such that they form at least one rectangular opening. In another example, however, the upper housing element and the lower housing element can also be designed and arrangeable such that they form a trapezoidal or diamond-shaped opening. According to the present invention it is preferred that the upper housing element forms one half or basically one half of the circumference or contour of the opening and the lower housing element forms the other half or basically the other half of the circumference or contour of the opening. In such an example, the trip unit is advantageously supported between the upper housing element and the lower housing element, because forces can be applied evenly from the trip unit onto the upper housing element and the lower housing element during operation of the circuit breaker.
In another example of the present invention the upper housing element and the lower housing element encircle and/or support the at least one protrusion. This results in a good form fit between the upper housing element, the lower housing element and the trip unit and such to an advantageous torsion resistance between these parts during operation. Further, the at least one protrusion can function as a guiding element when putting the upper housing element, the lower housing element and the trip unit together. The upper housing element and the lower housing element encircling or encompassing the at least one protrusion means that the upper housing element and the lower housing element contact or adjoin the at least one protrusion over its whole or basically whole circumference and/or over at least a certain width of its circumference.
Moreover, it is preferred according to the present invention that the at least part of the external wall of the upper housing element, the at least part of the external wall of the lower housing element and the at least part of the external wall of the frame element form a gapless external wall segment of the circuit breaker. With such a configuration it can be ensured that dielectric issues and/or effects, gasses and/or pollution may easily leave the trip unit and/or the circuit breaker. Gapless means that there is no visible hole or passage through which certain substances or particles may pass from the inside of the trip unit to the outside thereof.
In addition, it is preferred in the present invention that the frame element has the same length or basically the same length as the upper housing element and/or the lower housing element. With such a configuration it is possible to easily and securely assemble the upper housing element, the lower housing element and the trip unit together. There is no need to align the at least part of the external wall of the frame element, i.e., the external wall of the at least one protrusion for example, and the at least part of the external walls of the upper housing element and the lower housing element separately. When putting the trip unit, the upper housing element and the lower housing element together, the respective parts of the external walls will be automatically flush with each other. The frame element having the same length or basically the same length as the upper housing element and/or the lower housing element also means that the upper housing element and/or the lower housing element have the same length or basically the same length as the trip unit.
According to the present invention it is of further advantage when the upper housing element, the lower housing element and the frame element are made of the same material. In case of expansion, compression and/or other deformation of the upper housing element, the lower housing element and the frame element during operation of the circuit breaker, there is a reduced risk of stress between these parts. Therefore, the durability of the circuit breaker can be increased. Further, manufacturing these parts can be provided in an easy and inexpensive manner.
Further, it is preferred in accordance with the present invention that the upper housing element, the lower housing element and the frame element are designed such that they can be plug-connected with each other. By means of this connection the upper housing element, the lower housing element and the frame element can be put together and/or separated from each other in an easy and quick manner. For the plug-connection, the upper housing element, the lower housing element and the frame element may have plugs and/or reception holes and/or grooves. Such plugs and/or reception holes and/or grooves may be realized by respectively shaping at least part of the external walls of the upper housing element, the lower housing element and the frame element. Further, it is possible to provide separate plugs and/or reception holes and/or grooves in at least part of the external walls of the upper housing element, the lower housing element and/or the frame element. The reception holes and/or grooves may be formed inside said external walls and the plugs may be formed perpendicular and/or parallel to the external walls on at least one end side and/or edge of the external walls.
Further features can be derived from the following description of certain embodiments of the present invention, which are schematically shown in the drawings. Every feature of the claims, the description and the drawings can be essential considered alone or in combination with one or a plurality of other features.
In the drawings:

Figure 1: shows perspective illustration of a frame element of a trip unit according to the present invention,
Figure 2: shows an exploded side-view of a circuit breaker according to the present invention,
Figure 3: shows a cross sectional top-view of the circuit breaker according to the present invention, and
Figure 4: shows a sectional perspective illustration of an external wall segment of a circuit breaker according to the present invention.

In the Figures, elements with the same functions and effects are each marked by the same reference signs.
Fig. 1 shows a perspective illustration of a frame element 21 of a trip unit 20 according to an embodiment of the present invention. The frame element 21 of Fig. 1 has two protrusions 24 from two side faces of the frame element 21, wherein said protrusions 24 form part of the external wall 22 of the frame element 21. Further, according to the embodiment shown in Fig. 1, the frame element 21 comprises four z-shaped segments 26, two at each protrusion 24.
Fig. 2 shows an exploded side-view of an upper housing element 30, a trip unit 20 and a lower housing element 40 according to an embodiment of the present invention. As shown in Fig. 2, the trip unit 20 comprises the frame element 21, wherein part of an external wall 32 of the upper housing element 30 and part of an external wall 42 of the lower housing element 40 are flush in line F with part of an external wall 22 of the frame element 21. As can also be drawn from Fig. 2, the frame element 21 has the same length and/or width or basically the same length and/or width as the upper housing element 30 and the lower housing element 40. The upper housing element 30, the trip unit 20 and the lower housing element 40 are, of course, also flush with each other when being assembled. Fig. 3 shows such an assembled state of the upper housing element 30, the trip unit 20 and the lower housing element 40 in a cross-sectional top-view of the circuit breaker.
As shown in Fig. 4, the upper housing element 30 and the lower housing element 40 each have a side wall 32, 42 with a stepped shape at a front and/or end side. These stepped shapes are arranged such that they form a rectangular opening 50 between them, wherein the rectangular opening 50 has the same shape or basically the same shape as the end side of the protrusion 24 of the frame element. Even though there is shown only one side of the circuit breaker 10 in Fig. 4, in a preferred embodiment there are formed two openings 50 on two opposing sides of the circuit breaker 10 as suggested in Fig. 2. As further shown in Fig. 4, the upper housing element 30 and the lower housing element 40 encircle and/or support the at least one protrusion 24, wherein part of the external wall 32 of the upper housing element 30, part of the external wall 42 of the lower housing element 40 and part of the external wall 22 of the frame element 21 form a gapless external wall segment 12 of the circuit breaker 10. By means of the shapes of the frame element 21, the upper housing element 30 and the lower housing element 40 disclosed in Figures 1 to 4, there can be provided a plug-connection and/or a form fit and/or form lock connection between these parts.

Reference signs

10: circuit breaker
12: external wall segment
20: trip unit
21: frame element
22: external wall of the frame element
24: protrusion
26: z-shaped segment
30: upper housing element
32: external wall of the upper housing element
40: lower housing element
42: external wall of the lower housing element
50: opening

Claims

A circuit breaker (10), comprising:
an upper housing element (30), a lower housing element (40) and a trip unit (20) located between the upper housing element (30) and the lower housing element (40),

characterized in that

the trip unit (20) comprises a frame element (21), and at least part of an external wall (32) of the upper housing element (30) and at least part of an external wall (42) of the lower housing element (40) are flush with at least part of an external wall (22) of the frame element (21).
A circuit breaker (10) according to claim 1,
characterized in that
part of the external wall (22) of the frame element (21) is part of at least one protrusion (24) from at least one side face of the frame element (21).
A circuit breaker (10) according to claim 2,
characterized in that
at least one segment (26) of the protrusion (24) has a z-shape or basically a z-shape in cross-section.
A circuit breaker (10) according to claim 2 or 3, characterized in that
the upper housing element (30) and the lower housing element (40) are designed and arrangeable such that they form at least one opening (50) between them, wherein the at least one opening (50) has the same shape or basically the same shape as one side of the at least one protrusion (24).
A circuit breaker (10) according to any one of claims 2 to 4,
characterized in that
the upper housing element (30) and the lower housing element (40) encircle and/or support the at least one protrusion (24).
A circuit breaker (10) according to any one of the foregoing claims,
characterized in that
the at least part of the external wall (32) of the upper housing element (30), the at least part of the external wall (42) of the lower housing element (40) and the at least part of the external wall (22) of the frame element (21) form a gapless external wall segment (12) of the circuit breaker (10).
A circuit breaker (10) according to any one of the foregoing claims,
characterized in that
the frame element (21) has the same length or basically the same length as the upper housing element (30) and/or the lower housing element (40).
A circuit breaker (10) according to any one of the foregoing claims,
characterized in that
the upper housing element (30), the lower housing element (40) and the frame element (21) are made of the same material.
A circuit breaker (10) according to any one of the foregoing claims,
characterized in that
the upper housing element (30), the lower housing element (40) and the frame element (21) are designed such that they can be plug-connected with each other.