Trip gear for miniature circuit breaker

Abstract

The invention discloses a trip gear for a miniature circuit breaker. The trip gear for the miniature circuit breaker comprises a sealing pipe (4), a movable piece, a supporting frame (10) and a torsional spring (12), wherein the upper end of the sealing pipe (4) is sealed through a pole block (6), a limiting piece 13 is embedded in the upper portion of the pole block, the movable piece and the sealing pipe (4) are arranged in parallel, the movable piece comprises a horizontal movable head (7) and a movable arm (8) which is perpendicular to the movable head (7), the movable head (7) is located below one end of the limiting piece (13), a hanging hole (9) is formed in the middle of the movable arm (8), a tripping rod is arranged in the hanging hole (9), the upper end of the supporting frame (10) is tightly attached to the movable arm (8) to play a role in supporting, and the torsional spring (12) comprises a first stretching-out end and a second stretching-out end; overcurrent passes through a loading coil (5), flux is generated by the pole block (6), the movable piece overcomes the torsion of the torsional spring (12) to move close to the pole block (6), the tripping rod comes out of the hanging hole (9), and then a circuit is opened; the movable piece restores under the torsion of the torsional spring (12).

Description

technical field [0001] The invention relates to a circuit breaker, in particular to a tripping device for a small circuit breaker. Background technique [0002] Usually a miniature circuit breaker (Miniature Circuit Breaker, MCB) is installed on the circuit to protect the home or industrial switchboard system. It is a device that blocks overload, overcurrent or short-circuit current and dangerous currents that appear on simple lines, and protects the lower end or load. . [0003] The tripping device is the main accessory of the miniature circuit breaker. When dangerous currents such as overcurrent are connected, the contacts can be opened to block the inflow of current. The existing tripping devices are usually divided into two types: heat-sensitive type and completely electromagnetic type: heat-sensitive type The circuit breaker is moved by an armature composed of bimetallic strips heated by overcurrent. At this time, the tripping mechanism is activated to trip the circuit...

AI Technical Summary

Problems solved by technology

The disadvantage of this thermal tripping device is that it takes a certain amount of time for the thermal deformation of the bimetal strip to occur. When the overcurrent or short circuit blocking capacity exceeds the set capacity, the contact will be overheated and welded or the tripping device will be damaged.

This structure has the advantage of reducing the volume of the circuit breaker, but in order to prevent the movable piece from deviating from its position, a leaf spring structure is used, which makes the restoring force of the movable piece back to its original position relatively weak, so the movable piece will fall from the original position. If the trip position sucked by the pole piece cannot be restored to the original retracted position, a fault occurs that the trip bar cannot be fixed

In this patent, the structure connecting the bottom of the movable piece and the lower end of the leaf spring is used to prevent the movable piece from changing its position upwards, but the leaf spring alone cannot completely prevent the position of the movable piece from changing. The movable head at the upper end of the moving piece will be detached from the side of the pole piece, and tripping will not occur, so there is a problem of low reliability in blocking abnormal current

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