Patent ID: 7557683

Claim:
A switching device for a transfer switch comprising: a pivotal body having a pivotal axis being defined as an axis along which the pivotal body is pivotally connected to a base; a first recess defined in the pivotal body; a second recess defined in the pivotal body adjacent to the first recess; and a connecting axis defined between the first and second recesses; a solenoid connected to the pivotal body with a lever and having a driving shaft with a center line; a resilient pushing device mounted in the pivotal body; and a main spring having a connecting end being connected to the pivotal body at a point on the connecting axis, wherein the lever has a first end pivotally connected to the driving shaft of the solenoid and having a pivoting center; a second end provided with a positioning stub selectively held in one of the first and second recesses in the pivotal body and abutting with the resilient pushing device, and the positioning stub having a positioning center; and a center line defined between the pivoting center of the first end of the lever and the positioning center of the positioning stub; and the connecting end of the main spring connected to the connecting axis of the pivotal body is offset to the center line of the lever when the center line of the lever aligns with the center line of the driving shaft.