US 7,518,482 B2 · Trip unit having a plurality of stacked bimetal elements

Abstract

A trip unit in a miniature circuit breaker having a plurality of stacked bimetal elements welded front-to-back at one end and attached to a load terminal. The bimetal elements are made of similar compositions and have the same thickness. The free ends are connected to a yoke and to a pigtail that is optionally wound around the yoke in which the bimetals are received. The pigtail is connected to the conductive blade of the trip unit. To attach the pigtail from one direction, a notch is formed in the free end of one of the bimetals, exposing part of the other bimetal behind it. Or, two notches are formed in a staggered relationship such that the pigtail connections can be made from either direction. The stacked relationship of the bimetal elements allows the overall width of the circuit breaker to be reduced without sacrificing its rating requirements with one bimetal.

Claims20

Dependent claims

A trip unit for a circuit breaker, comprising:

a first bimetal having a load end and a free end;
a second bimetal having a free end and attached front-to-back to said first bimetal at said load end;
a load terminal attached to an exposed surface of said first bimetal at the load end thereof;
a pigtail conductor, for electrical connection to a conductive blade of said trip unit, attached to exposed surfaces of said first and second bimetals at the respective free ends thereof;
and
a yoke at least partially receiving said first and second bimetals, said yoke being attached to the free end of said first bimetal or said second bimetal.

3 more elements

Dependencies are inferred from the claim text.

Trip unit having a plurality of stacked bimetal elements

Life of this patent

Trip unit having a plurality of stacked bimetal elements

Life of this patent

Abstract

Claims20