The invention relates to a switch mechanism for an electrical installation switch device comprising a switch toggle for manually operating the switch device, at least one contact point with a stationary and a movable contact element, said contact point possibly being a double contact point, a toggle mechanism located between the switch toggle and the at least one movable contact element, said toggle mechanism maintaining the contact point closed in a first stable position, and a tripping lever operated by a tripping device that influences the toggle mechanism in such a way that the toggle mechanism is moved from its first stable position (switch-on position) to a second position (switch-off position) via a dead point position. The toggle mechanism includes a link (26) that is hingedly connected to the movable contact element (28) and a bracket (24) having two limbs (23, 25), one of which (25) is connected to the other end of the link (26) while the other (23) is connected to the toggle lever (18). When tripping occurs, the tripping lever (33) impinges upon the toggle mechanism approximately perpendicular to said toggle mechanism in the area of knee point in the direction of the second stable position. |