Arc extinguishing device having a focused field

An electrical distribution device comprising:

• a housing;
• a pair of electrical contacts positioned within the housing, at least one contact being moveable in and out of engagement with the other along a pre-determined path;
• an arc extinguishing device disposed along the pre-determined path of movement, the device having a generally U-shaped member having a bight portion defined by a bottom wall with two upstanding side walls, the bight portion having sufficient width to allow the movement of the electrical contacts between the two side walls;
• a pair of magnetic poles having a magnetic field therebetween, one of the poles being formed with and located near the top edge of each side wall;
• and
• means for focusing the magnetic field along the longitudinal center axis through the length of the U-shaped member and in the plane overlapping the path of movement of the electrical contacts so as to increase the magnetic flux density encountered by the arc created by interrupting the electrical contacts the focusing means having a focusing member integrally formed with each side wall near the top edge and extending perpendicularly inward therefrom.

A method of assembling an arc extinguishing device, the method including the step of:

• interlocking a plurality of magnetic material plates into the shape of a yoke, the yoke including:
• a generally U-shaped member having a bight portion defined by a bottom wall with two upstanding side walls, the bight portion having sufficient width to allow the movement of the electrical contacts between the two side walls;
• a pair of magnetic poles having a magnetic field therebetween, one of the poles formed with and located near the top edge of each side wall;
• and
• means for focusing the magnetic field along the longitudinal center axis through the length of the U-shaped member and in the plane overlapping the path of movement of the electrical contacts so as to increase the magnetic flux density encountered by the arc created by interrupting the electrical contacts, the focusing means having a focusing member integrally formed with each side wall near the top edge and extending perpendicularly inward therefrom.