| 摘要 |
<p>A circuit breaker (301) for interrupting the flow of current upon the detection of excess current or temperature is provided that has a current conducting blade mounted on a blade cross bar (333), which has a blade biasing spring (329) for urging the blade to a first pivotal position on the blade cross bar during the open, closed, and tripped operation of the breaker, and for latching the blade in a second pivotal position on the blade cross bar upon the occurrence of a blown-open action of the breaker. The spring (329) is a torsion spring that is coiled around a spring mounting pin (341), having a first end leg extending outwardly and formed into a hook (335) anchored in a hook accommodating opening, and having a second end leg extending outwardly and cantilevered in contact with a spring follower pin (345). The second end of this leg is bent away from the spring follower pin to reduce the spring force exerted between the blade cross bar and the blade upon the occurrence of a blow-open action of the circuit breaker. Attached to the blade is a blade pivot pin that is generally cylindrical and that has a center section of reduced diameter establishing shoulders on the pin on both sides of a hole in the blade, so that upon application of force on the blade by the spring, the blade pivot pin is locked against displacement from the hole. On the blade cross bar a barrier is provided so positioned that upon pivoting movement of the blade cross bar to a tripped, open, or blown-open position, the barrier is interposed between the spring and the fixed contact, thereby protecting the spring from debris generated in the vicinity of the fixed contact. <IMAGE></p> |
