Arc extinguishing unit, interruption unit, and air circuit breaker comprising same

A circuit breaking unit, comprising:

• a fixed contact terminal having a fixed contact disposed at a first end thereof and extending in a first direction;
• a movable contact terminal comprising a movable contact and configured such that the movable contact is formed to move toward the fixed contact or away from the fixed contact;
• a low runner disposed extending in the first direction from the fixed contact, a first end of the low runner coupled to the fixed contact terminal, and a second end of the low runner spaced apart from the fixed contact terminal;
• a protruding contact disposed to extend in the first direction from the movable contact and formed to be in contact with the low runner or spaced apart from the low runner, wherein the protruding contact is arranged to be surrounded by a grid leg that extends in a second direction, opposite to the first direction, from both sides of a grid of an arc extinguishing unit;
• and
• a U assembly disposed between the low runner and the fixed contact terminal, extending away from the fixed contact terminal and toward the movable contact, and formed to surround a side of the grid leg.

An arc extinguishing unit, comprising:

• two side plates spaced apart from each other and disposed to face each other;
• a grid cover disposed between and coupled to the two side plates on a first end of the two side plates;
• a plurality of grids disposed between the two side plates, wherein each grid of the plurality of grids is spaced apart from each other grid of the plurality of grids and is coupled to the two side plates,
• wherein each grid of the plurality of grids comprises a grid leg extending in a first direction towards a second end of the two side plates, opposite to the first end, to surround a protruding contact disposed to extend in a second direction, opposite to the first direction, from a movable contact;
• a first protective part formed to surround at least a first portion of the grid leg of each grid the plurality of grids, and
• a second protective part formed to surround at least a portion of an area where the first protective part is exposed to an outside of the arc extinguishing unit,
• wherein the grid leg of an outermost grid of the plurality of grids closest to a fixed contact among the plurality of grids has a width narrower than widths of other grid legs associated with other grids of the plurality of grids;
• wherein an outermost insertion groove for accommodating the grid leg of the outermost grid of the first protective part is formed to correspond to the width of the grid leg of the outermost grid, and
• wherein a concave region is formed in the first protective part by being recessed in a direction toward the protruding contact of the outermost insertion groove disposed in a direction toward the fixed contact.

An arc extinguishing unit, comprising:

• two side plates spaced apart from each other and disposed to face each other;
• a grid cover disposed between and coupled to the two side plates on a first end of the two side plates;
• a plurality of grids disposed between the two side plates, wherein each grid of the plurality of grids is spaced apart from each other grid of the plurality of grids and is coupled to the two side plates,
• wherein each grid of the plurality of grids comprises a grid leg extending in a first direction towards a second end of the two side plates, opposite to the first end, to surround a protruding contact disposed to extend in a second direction, opposite to the first direction, from a movable contact;
• a first protective part formed to surround at least a first portion of the grid leg of each grid the plurality of grids and coupled to a first plate of the two side plates,
• a second protective part formed to surround at least a portion of an area where the first protective part is exposed to an outside of the arc extinguishing unit, and
• a third protective part formed to surround at least a second portion of the grid leg of each grid the plurality of grids,
• wherein the first protective part is coupled to a first side plate of the two side plates and the third protective part is coupled to a second side plate of the two side plates so that the first protective part and the third protective part face each other,
• wherein the first protective part and the third protective part each comprise:
• a first surface surrounding a first surface of the grid leg of each grid of the plurality of grids;
• and
• a second surface extending at a predetermined angle with respect to the first surface and surrounding a second surface of the grid leg of each grid of the plurality of grids that faces an opposing side plate of the two side plates, and wherein the second protective part comprises:
• a first portion formed to cover the first surface of the first protective part;
• a second portion formed to cover the second surface of the first protective part and extending by being bent with respect to the first portion;
• a third portion that is bent with respect to the first portion, extends between the first protective part and a first side plate of the two side plates to be coupled to the first protective part and the first side plate;
• a fourth portion that is bent with respect to the second portion and extends, and is formed to surround a direction away from a fixed contact of the first protective part;
• and
• a fifth portion that is bent with respect to the fourth portion and extends between the first protective part and the first side plate to be coupled to the first protective part and the first side plate.