Abstract: An electric circuit breaker or load switch has at least one fixed contact, a movable contact and a spring system having a rigid arm and a leaf spring. The leaf spring is hinged to the arm to provide an arm-leaf spring assembly in the form of a toggle mechanism, having a first end hinged to a movably supported element bearing the movable contact, and a second end which is hingedly supported at a distance from and opposite the fixed contact. The second end, the first contact and the movable element are positioned such that the arm-leaf spring assembly in both the open and closed position of the contacts assumes a deflected position, by which the connection length of the switch is effectively reduced.

Abstract: An improved trip device for an electric switch comprises a yoke, a permanent magnet immovably positioned with respect to the yoke and a movably supported armature forming a first magnetic circuit, in which the armature is able to assume a first position under the influence of the magnetic field of the permanent magnet. A magnet winding and spring are provided for causing the armature to assume a second position in response to the magnetic field generated by an electric current, flowing during operation in the magnet winding. For adjusting the threshold value at which the armature is moved to its second position, a second magnetic circuit in the form of shunt interacting with the yoke and the permanent magnet is provided. The magnetically effective surface area of the shunt is smaller in the vicinity of the section thereof which interacts with the yoke than in the vicinity of the section which interacts with the permanent magnet.