Circuit breaker

Abstract

A circuit breaker is comprised of a make-and-break mechanism part disposed between frame plates opposite to each other; a base in which a breaking portion including cross bar, moving contact, fixed contact and arc-extinguishing device, and an over-current trip device are contained; a middle base, in which a partition wall separating the breaking portion from the make-and-break mechanism part, and the breaking portion from the over-current trip device, is provided; and a cover for covering the base and middle base. A frame of the make-and-break mechanism part is secured to the base through the middle base, and the secured part of the frame and the inner bottom face of the base are disposed in the proximity.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a circuit breaker according to a first preferred embodiment of the present invention.

FIG. 2 is cross sectional view taken along the line A-A in FIG. 1.

FIG. 3 is a view taken in a direction indicated-by the arrow B of a middle base in FIG. 1.

FIG. 4 is a view taken in a direction indicated by the arrow C of the middle base in FIG. 1.

FIGS. 5( a) and (b) are cross sectional views taken along the line D-D and the line E-E in FIG. 3 respectively.

FIG. 6 is an exploded perspective view of a circuit breaker when the middle base is detached.

FIG. 7 is a perspective view showing a circuit breaker after assembly.

FIG. 8 is an external perspective view of a base and a middle base according to a second embodiment of the invention.

Claims

1. A circuit breaker comprising: a make-and-break mechanism part that includes an operating handle, and is disposed between frame plates opposite to each other;a base in which a cross bar that turns in cooperation with said make-and-break mechanism part, a moving contact that cooperates with said cross bar, a fixed contact that repeats the contact and separation from said moving contact, a breaking portion including an arc-extinguishing device functioning to extinguish arc generated between both of said contacts; and an over-current trip device are contained;a middle base in which a partition wall serving to separate said breaking portion from said make-and-break mechanism part, and said breaking portion from said over-current trip device, is provided; and in which said make-and-break mechanism part is contained; anda cover with which said base, middle base and each of parts contained in said base and middle base are covered;wherein a frame of said make-and-break mechanism part is secured to said base through said middle base; and the secured part of said frame and the inner bottom face of said base are disposed in the proximity.

2. The circuit breaker according to claim 1, wherein said frame plate is provided with pairs of threaded parts to be secured by means of screws through the middle base from the underside of said base respectively; and a base part- of said middle base is in contact with the inner bottom face of the base.

3. The circuit breaker according to claim 1, wherein said middle base is provided with a first hole through which a lower link of said make-and-break mechanism part goes to be coupled to the cross bar, and a second hole formed in a base part; and said first hole is slot-shaped conforming to the turning range of said lower link when make-and-break of said both of the contacts is made with said operating handle being turned.

4. The circuit breaker according to claim 3, wherein said middle base is further provided with a hole, which is formed generally between phases of the middle base, and through which a protrusion that is formed at said cross bar goes; and said hole is slot-shaped conforming to the turning range of the cross bar.

5. The circuit breaker according to claim 1, wherein a partition wall of said middle base consists of a horizontal part to separate said breaking portion from the make-and-break mechanism part, and a vertical part to separate said breaking portion from the over-current trip device.

6. The circuit breaker according to claim 1, wherein side plates that are provided at two side faces of the middle base in parallel with an electric circuit direction of said circuit breaker are fit into concave portions formed in the base, whereby said middle base forms a part of an insulating housing of said circuit breaker.

7. The circuit breaker according to claim 1, wherein an arc-extinguishing device holding part is-provided at a position opposite to said arc-extinguishing device of the middle base.

8. The circuit breaker according to claim 1, wherein a stopper is provided at a position opposite to said moving contact of the middle base.

9. The circuit breaker according to claim 1, wherein a threaded part of said frame plate and a bottom of said base are directly secured with screws via a spacer when said middle base is removed.

10. The circuit breaker according to claim 1, wherein in case of forming a four-pole circuit breaker having three voltage poles and one neutral poles said middle base is mounted onto said voltage poles.