Low-voltage protective circuit breaker with locking lever

In a circuit breaker comprising a housing, at least one stationary contact and one movable contact, a control shaft, a carrier mounted on the control shaft and connected to the movable contact to move the same relative to the fixed contact, a handle, an actuating lever connected to the handle to be controlled thereby, a pressure spring connected to the carrier and to the movable contact to exert pressure on the movable contact to force it toward the fixed contact, a drive spring connected to the actuating lever, and a toggle lever system engaging the carrier, and including a toggle joint pin, the invention comprising:

• a locking lever, one end of the locking lever engaging the handle;
• pivotal support means for the locking lever;
• a first working surface of the locking lever;
• an abutting surface on the carrier opposite the working surface and spaced therefrom by a distance less than the distance the working surface moves when the operating handle moves from its "on" position to its "off" position:
• and
• a second working surface on the locking lever opposite the toggle joint pin of the toggle lever system to engage the toggle joint pin at an intermediate position in the path of movement of the locking lever.