阅读说明：本技术 用于微型断路器的瞬时跳闸装置和包括该跳闸装置的微型断路器 (Instantaneous trip device for miniature circuit breaker and miniature circuit breaker including the same ) 是由 阿卜杜勒·萨拉姆·阿勒穆特拉克 于 2018-04-02 设计创作，主要内容包括：提供一种具有瞬时跳闸装置的微型断路器,该瞬时跳闸装置具有L形柱塞和阶梯式跳闸杠杆。该构造能够将线性力有效地转换成旋转力,从而提供电触点的快速打开。(A miniature circuit breaker is provided with an instantaneous trip device having an L-shaped plunger and a stepped trip lever. This configuration can efficiently convert a linear force into a rotational force, thereby providing rapid opening of the electrical contacts.)

1. An instantaneous trip device for a miniature circuit breaker includes a solenoid having an L-shaped plunger.

2. A miniature circuit breaker comprising:

a. a solenoid having an L-shaped plunger, and

b. a trip bar configured to rotate when activated by the L-shaped plunger.

3. The miniature circuit breaker of claim 2, wherein the trip bar is stepped.

4. The miniature circuit breaker of claim 2 or 3, wherein the trip lever is configured to rotate counterclockwise into a contact arm of the moving contact, thereby separating the moving contact from a fixed contact.

5. The miniature circuit breaker of claim 4, wherein the trip bar and the contact arm have the same pivot point.

6. The miniature circuit breaker of any one of claims 1-5, wherein the trip bar is configured when activated to lift the moving contact.

7. The miniature circuit breaker of claim 4, wherein the trip bar comprises a moving contact support.

8. The miniature circuit breaker of claim 7, wherein the trip bar includes a circular opening through which the trip bar is rotatably mounted to the housing by a pin.

9. The miniature circuit breaker of claim 8, wherein the circular opening has a lip.

10. The miniature circuit breaker of claim 9, comprising a contact pressure spring configured to maintain contact between said moving contact and said stationary contact when said miniature circuit is completed.

11. Combining the unique stepped profile of the plunger of claim 2 and the trip bar of claim 3 provides for efficient transfer of the gasket force and motion to the rotational force and motion, thereby achieving contact separation in a minimum amount of time.

Technical Field

The present invention relates to the field of miniature circuit breakers, and in particular, to an instantaneous trip device having a stepped lever for a miniature circuit breaker.

Background

Circuit breakers protect electrical circuits from damage caused by current surges by interrupting or breaking the current path between the input and output terminals. A conventional miniature circuit breaker comprises a pair of contacts in a main current path between a line side for connection to a power source and a load side for connection to a load to be powered by the power source. Conventional miniature circuit breakers also include an instantaneous trip mechanism to sense short circuit conditions in which overcurrent surges through the main current path are large. The trip mechanism provides a command to the mechanism for opening the contacts. The contacts include a fixed contact and a movable contact. The movable contact is attached to a pivotable contact arm.

The instantaneous trip mechanism typically includes an electromagnet and an armature that, when a short circuit occurs, pushes a plunger into a contact arm of the movable contact, pivoting the contact arm, thereby opening the circuit.

The plunger is linear and the trip mechanism requires rotational movement to pivot the arm, resulting in energy loss during this change in the conventional mechanism.

The applicant provides well-known information believed to be of possible relevance to the present invention. Applicants do not intend for any information above to be admitted or constitute prior art against the present invention.

Disclosure of Invention

The invention aims to provide an instantaneous trip device for a miniature circuit breaker and the miniature circuit breaker comprising the same. According to one aspect of the present invention, an instantaneous trip device for a miniature circuit breaker is provided, which includes a solenoid having an L-shaped plunger.

According to another aspect of the present invention, there is provided a miniature circuit breaker including a solenoid having an L-shaped plunger and a trip bar configured to rotate when activated by the L-shaped plunger. In one embodiment, the trip lever is stepped.

The invention provides a miniature circuit breaker (1) having an instantaneous trip device (21), the instantaneous trip device (21) effectively converting a linear force into a rotational force to rotate a moving contact to rapidly open an electrical contact. In particular, the unique structure of the trip lever and plunger effectively converts linear motion of the plunger into rotational motion via the trip lever to facilitate rapid separation of the fixed and moving contacts. Miniature circuit breakers that open contacts quickly minimize the amount of energy within the circuit breaker during fault clearing.

With reference to the figures, the miniature circuit breaker (1) is provided with an instantaneous trip device (21) for opening the contacts in the event of a current. The miniature circuit breaker (1) comprises a housing or casing, optionally arranged in two connectable halves, the circuit breaker assembly providing a main current path between an input and an output. Suitable housings or shells are known in the art. The housing or shell is typically plastic and includes suitable mounting and insulating elements. The circuit breaker assembly includes an instantaneous trip device (21) operatively connected to the handle assembly, the fixed contacts and the moving contacts. The handle assembly is movable between a normal position and an abnormal or fault position (indicating a tripped circuit) and includes an operator or handle (3) and an associated handle spring (2). The handle assembly is connected to the trip bar by a link (4).

The handle spring (2) is configured to bring the handle (3) to the OFF position when the miniature circuit breaker (1) trips.

As shown, the fixed contact is attached to a side edge of the yoke (14) by a fixed contact arm (24). The moving contact (22) is configured to rotate into and out of contact with the fixed contact and is supported by the contact support arm (10) and the trip lever.

A contact pressure spring (19) is flexibly associated with the moving contact and the trip lever and is configured to maintain a desired value of a contact pressure with the fixed contact in an ON state.

Referring to fig. 2, the instantaneous trip device (21) includes an electromagnetic mechanism including a yoke (14) having a first end and a second end, a yoke brush (3), a solenoid having a coil (17), a hollow stationary core (16), a moving core or armature (12), a retaining spring (18), and a plunger (15). Specifically, the yoke (14) surrounds a solenoid (17), and the solenoid (17) is connected to the circuit. A hollow stationary core (16) is riveted to the yoke at a second end and extends axially into the coil. The plunger is an "L" shaped plunger (15) axially passing through the hollow central axis of the stationary core (16) and selectively securable in position in the moving core (12) by interference fit. And provides a retained compression spring (18) as shown in figure 2.

In the normal operating condition shown in fig. 3, i.e. the ON condition, the fixed spring (18) holds the moving core (12) and the associated plunger (15) in position. The plunger (15) abuts the trip bar (7). The fixed contact and the movable contact (22) are in contact and the circuit is open. The moving contact (22) is attached to the rest of the circuit by a metal braid (61).

Referring to fig. 5, when a large surge (i.e., a short circuit in current) occurs through the main current path, the instantaneous trip device (21) generates a magnetic field that acts on the moving core (12) with a force that overcomes the holding force of the holding spring (18) such that the moving core (12) and associated plunger (15) move laterally in the direction of the stationary core (16). The plunger (15) activates the trip bar (7) to rotate.

Referring to fig. 4A and 4B, the trip lever (7) includes a first wall (71) and a second wall (72) and a floor (73) therebetween. The base plate is stepped and configured to be engaged by a plunger (15) such that when a short circuit occurs in the current, the plunger engagement causes the trip bar to rotate counterclockwise. The trip bar includes a circular opening (74) and is rotatably mounted to the housing by a contact support and a mechanism pin (75). The trip bar comprises a rotatable contact support arm (10) and two spring contact points. The first spring contact point is a raised lip (76) surrounding a circular opening (74) sized to fit within the coils of the spring, and the second contact point is a raised boss (77) having a recess (78), the recess (78) configured to receive the free end of the spring. The second free end of the spring hook is on the moving contact.

The trip bar is configured to convert a linear force moving the plunger (15) into a rotational force by acting on the stepped trip bar (7). When the opening mechanism is activated, the trip lever (7) rotates counterclockwise into the arm of the moving contact (22), thereby transferring a rotational force to the arm of the moving contact (22) and forcing the moving contact (22) apart from the fixed contact. The opening spring (20) facilitates separation of the contacts by providing the opening speed required to rotate the moving contact (22) during the OFF operation. The instantaneous trip device (21) is structured to rapidly open the circuit by separating the two contacts so that when the opening mechanism is first activated, the handle (3) remains in the "ON" position due to inertia. When the moving contact (22) continues its counterclockwise movement, the handle spring (2) moves the handle (3) to the OFF position through the operable connection of the trip lever (7) via the link (4). The contact brackets and the cam profiles in the trip bar together lock the connecting bar (4) from sliding off during normal switching operation.

When an excessive short circuit occurs, a large magnetic field is generated by the coil of the solenoid (17), and a large force is generated to act on the moving core (12). This causes the plunger (15) to move at high speed into contact with the trip bar (7), thereby triggering the contact opening mechanism in a very short period of time.

Furthermore, since the moving core (12) moves at high speed, the plunger (15) hits the trip bar (7) with a large amount of force, which causes the trip bar (7) to rotate rapidly into contact with the moving contact (22), mechanically assisting the opening of the contacts, i.e. triggering the contact opening mechanism in addition thereto. This mechanical assistance helps prevent the contacts from being soldered together due to the very large current flowing between them. This welding of contacts is called "stick" welding and is a risk at very high short circuit currents (e.g., 1000A to 2000A).

While the invention has been described with reference to certain specific examples, various modifications thereof will be apparent to those skilled in the art without departing from the spirit and scope of the invention. All modifications in this area of art that are obvious to the skilled person are intended to be included within the scope of the appended claims.