External operation handle device for a circuit breaker

Abstract

An external operation handle device is used for a circuit breaker for switching a locker handle to ON and OFF positions. The handle device includes a main body casing for the circuit breaker, a mount base held on the main body casing, a rotary handle grip mounted on the mount base for turning the locker handle to the ON and OFF positions and having a connecting shaft, and an assist mechanism for moving the handle grip to a TRIP indication position upon tripping operation of the circuit breaker. The assist mechanism is interposed between the mount base and the handle grip, and includes a cam with a cam face, fixed on the mount base, a cam follower linking with the handle grip slidably along an axial direction and opposing the cam face of the cam, and an urging spring for pushing the cam follower against the cam face.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical sectional view of an external operation handle device of an embodiment according to the preset invention, the handle device being mounted on a circuit breaker;

FIG. 2 is an exploded perspective view of the external operation handle device in FIG. 1;

FIG. 3 illustrates an operational status of the external operation handle device corresponding to ON position in FIG. 1;

FIG. 4 illustrates an operational status of the external operation handle device in a trip operation of the circuit breaker;

FIG. 5 is a side sectional view of an external operation handle device of a prior art in combination with a circuit breaker;

FIG. 6 is a perspective view of FIG. 5;

FIG. 7 is a plan view of the external operation handle device in FIG. 5; and

FIG. 8 is a view from a back surface around a slide base illustrating an assist structure provided in the external operation handle device of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment, according to the present invention, will be described in the following with reference to FIGS. 1 through 4. In the Figures, parts corresponding to the parts shown in FIGS. 5 through 8 are designated by the same reference numerals, and their description is omitted.

In the external operation handle device 2 of the embodiment shown in the Figures, a handle grip 4 and a turn base 5 are connected by a connecting shaft 9 with a hollow structure. In the hollow connecting shaft 9 between the handle grip 4 and the turn base 5, an assisting mechanism 14 is provided, which comprises a cam 10, a cam follower 11a, an urging spring 12, and a spring cover 13.

As shown in the disassembled drawing of FIG. 2, a square rod portion 9a at the top of the hollow connecting shaft 9 is press-fitted into a hole opened on the bottom surface of the handle grip 4, and the engaging protrusions 9b formed around the periphery of the bottom of the connecting shaft are fitted to engage holes opened on the plate face of the turn base 5, thereby connecting the handle grip 4 and the turn base 5.

The cam 10 of the assisting mechanism 14 is a cylindrical end face cam with a cam face 10a having peaks and valleys extending in an axial symmetry and formed on the end face of the cam. The cam 10 is engaged with a cross-shaped protrusion 3d provided on the center of the upper surface of the mount base 3 and fixed at this position. The cam follower 11a, disposed above and opposing the cam 10, is assembled with an urging spring (a compression spring) 12 and a cover 13 that are inserted to a square stud 11b, and fitted to a square pit formed at the top portion of the hollow connection shaft 9 in a fit drive connection manner. The cam follower 11a has, at the lower end thereof, a contact 11a with a protruding wall shape such that it radially crosses by the cam face 10a of the cam 10.

In the mount base 3 in FIG. 2, the reference numeral 3a designates legs for fixing on a main body casing 1a of the circuit breaker 1 (FIG. 5), the numeral 3b designates rails for sliding to guide and support the slide base 6, and the numeral 3c designates a guide for engaging and supporting the handle cover 7. A ring-shaped guide rail 7a is formed on the handle cover 7 for rotating to guide and support the handle grip 4.

The operation of the assisting mechanism, having the above-described structure, is described in the following. In the closed state of the circuit breaker in which the handle grip 4 of the external operation handle device 2 has been moved to the ON position, the contact of the cam follower 11a connected to the handle grip 4 sits on the peaks of the cam face formed at the end face of the cam 10, and stops to be held at this position as shown in FIG. 3. When the circuit breaker trips and the handle grip 4 of the external operation handle device 2 starts to rotate towards the TRIP indication position following the movement of the locker handle 1e of the circuit breaker 1 as described previously referring to FIG. 5, the contact of the cam follower 11a connected to the handle grip 4 acceleratedly slips down along the slanted face from peaks towards valleys of the cam face formed on the end face of the cam 10 receiving a spring force from the urging spring 12, and at the same time, the spring force of the urging spring 12 gives a torque in the counterclockwise to the cam follower 11a.

As a result, the handle grip 4 is acceleratedly moved from the ON position to the TRIP indication position overcoming the frictional force acting against sliding of the movable parts (turn base 5, slide base 6 and others) of the external operation handle device 2. Therefore, correct indication of trip operation of the circuit breaker is ensured.

Furthermore, the assisting mechanism 14 comprises the cam 10, the cam follower 11a, the square stud 11b, the urging spring 12, and the spring cover 13. The assisting mechanism 14 is disposed concentrically in the hollow connecting shaft 9 that connects the handle grip 4 and the turn base 5, and covered by the handle cover 7 around the assist mechanism. Therefore, the external operation handle device 2 is smaller than the conventional one with the structure as shown in FIG. 8.

The disclosure of Japanese Patent Application No. 2006-147718 filed on May 29, 2006 is incorporated as a reference.

While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.

Claims

1. An external operation handle device for a circuit breaker with a locker handle for switching the locker handle to ON and OFF positions, comprising: a main body casing for the circuit breaker,a mount base held on the main body casing,a rotary handle grip mounted on the mount base for turning the locker handle to the ON and OFF positions and having a connecting shaft, andan assist mechanism for moving the handle grip to a TRIP indication position upon tripping operation of the circuit breaker, the assist mechanism being interposed between the mount base and the handle grip, and including a cam with a cam face, fixed on the mount base, a cam follower linking with the handle grip slidably along an axial direction and opposing the cam face of the cam, and an urging spring for pushing the cam follower against the cam face.

2. An external operation handle device according to claim 1, wherein the cam has a cylindrical shape having cam faces of peaks and valleys formed symmetrically at an end face of the cam, and the cam follower has a protruding contact transversely crossing the end face of the cam.

3. An external operation handle device according to claim 2, wherein the cam follower is disposed inside the connecting shaft, and the urging spring is a coil spring disposed around the cam follower.

4. An external operation handle device according to claim 1, wherein the assist mechanism is disposed concentrically in a hollow shaft connecting the handle grip and a turn base.

5. An external operation handle device according to claim 1, further comprising a turn base connected to the handle grip through the connecting shaft, and a slide base linked to the turn base and slidably guided and supported by rails provided on the mount base.

6. An external operation handle device according to claim 1, further comprising a distribution board or a control board to which the external operation handle device is attached.