Large-fracture circuit breaker

Abstract

The invention discloses a large-fracture circuit breaker, and belongs to the technical field of low-voltage electric appliances. The large-fracture circuit breaker comprises a pair of bases, a movable contact, a fixed contact, an operating mechanism and a movable contact transmission. The operating mechanism comprises a handle knob assembly, a middle connecting rod, a movable contact support, a latch and an unlocking part, the movable contact transmission comprises a movable contact arm and a spring, and the movable contact support is provided with a driving surface. The large-fracture circuit breaker is characterized in that the movable contact transmission further comprises a first pivot arranged on the bases, a first opening with a first acting surface is arranged between a supporting point and a third acting surface, a second opening with a second acting surface is arranged between the first opening and the supporting point, and when the movable contact and the fixed contact which are in contact with each other are driven by the movable contact to be separated from the each other, a mode that the movable contact arm rotates under the condition of contact between the second acting surface and a second pivot is changed into a mode that the movable contact arm rotates under the condition of contact between the first acting surface and the first pivot. The large-fracture circuit breaker has the advantages that the insulating strength is improved, the stability of contact pressure between the movable contact and the fixed contact is guaranteed, and a perfect self-cleaning effect is realized.

Description

technical field [0001] The invention belongs to the technical field of low-voltage electrical appliances, and in particular relates to a large-fracture circuit breaker. Background technique [0002] China Invention Patent Authorization Announcement No. C201083611C (Publication No. C2097104909A) discloses an operating mechanism for a circuit breaker with a wide opening angle. (Axis of rotation) staggered setting, the pivot is located between the mandrel and the movable contact. Compared with the prior art of this patent, in which the mandrel of the moving contact arm and the pivot of the moving contact support are arranged coaxially, it has the technical effect of a large transmission ratio, and the moving contact arm can obtain a larger opening angle Displacement, so that the circuit breaker can obtain a larger electrical isolation gap without changing the transmission ratio of the operating mechanism. In addition, in the movable contact transmission device of this patent ...

AI Technical Summary

Problems solved by technology

Although such a design achieves a larger electrical isolation gap, it has the following disadvantages: the offset arrangement of the moving contact support and the moving contact arm (not using coaxial arrangement) can play a role in a large transmission ratio, but, Since the spring used to provide the contact pressure between the dynamic and static contacts when the circuit breaker is closed must be installed on the mandrel of the movable contact arm, however, starting from the principle of torque balance, the contact pressure between the dynamic and static contacts The greater the force arm of the spring, the greater the actual output torque of the spring, which is the only way to ensure the contact pressure of the dynamic and static contacts.

Therefore, if the actual output torque of the spring is to be increased, it becomes more difficult to arrange the spring in a limited space.

In particular, there are inevitable manufacturing errors in the spring itself, and manufacturing errors will cause contact pressure errors between the dynamic and static contacts. The laborious lever design of the above patent will further increase the contact pressure between the dynamic and static contacts of the circuit breaker. In the case of industrial mass production, it is difficult to control the consistency or stability of the contact pressure

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