Patent ID: 7297885

Claim:
A pressure switch comprising: a box having a space therein and including a close end and an open end; an outer cover connected to the open end of the box and an inlet defined through the outer cover; an inner cover engaged with the open end and having a central hole; a film located between the outer cover and the inner cover, a push portion extending from the film and extending through the central hole of the inner cover; an initializing device located in the space of the box and having a rod and a first spring mounted to the rod, the rod having one end extending through the close end of the box and the other end of the rod connected with the inner cover; a first plate received in the box and having a pivot end pivotably connected to the inner cover, a mounting hole defined through the other end opposite to the pivot end of the first plate and the rod extending through the mounting hole, the first spring contacting the rod, a through hole defined through the first plate; a second plate extending through the through hole of the first plate and having a lug, the second plate connected to the inner cover, the second plate connected to the first plate by a fourth spring, and an activation device located between the space of the box and the second plate, the activation device including a pull rod which has one end connected to a frame guided by rails, the other end of the pull rod connected to the lug of the second plate, the frame connected to a first contact unit and a second contact unit located on the two sides of the pull rod, the first contact unit including a first upper contact portion and a first lower contact portion, the second contact unit including a second upper contact portion and a second lower contact portion, the first and second contact units moved with the pull rod so that the first upper and lower contact portions and the second upper and lower contact portions are in contact with each other or separated from each other.