Abstract: In a locking arrangement of an electric circuit breaker which includes a latch and a locking strap which cooperates with the latter and is supported by means of two pivots in support openings of stationary parts, the pivots having a rectangular cross-section and arranged so that the force exerted by the latch on the locking strap is transmitted to one of the small surfaces of the pivots, the support openings have a convex surface which cooperates with the one small surface of the pivot and the long surfaces of the pivots are opposite similarly convex surfaces of the support openings. For the other small surface of the pivots, a concave surface or a surface which consists of two subsurfaces which are at an angle to each other and are connected by a transition arc is provided. The pivots cooperate with the support openings by rolling and sliding motions which insure low stress on the contact surfaces.

Abstract: An actuating device for attachment to a toggle actuated low-voltage circuit breaker having an insulating housing has a housing and a guide mechanism supported therein including a fork-shaped lever which can be turned and which transforms the rotary motion into the rectilinear motion needed to actuating the toggle lever. A slider, movably guided radial to the axis of rotation by the fork arms of the lever, has a circular cylindrical opening which receives a substantially spherical head piece. The head piece contains an opening for receiving the end of the toggle lever. The housing of the actuating device contains a slideway which serves as a guide surface for the head piece. An operating handle can be placed on a shaft end of the fork-shaped lever.