Low-voltage protective circuit breaker with a forked locking lever

A low-voltage circuit breaker comprising a drive lever, an operating handle to move the drive lever, a drive spring connected to the drive lever to be operated thereby, a toggle system including two toggle levers and a toggle joint connecting the levers together, a control shaft connected by the toggle lever system and the drive spring to the drive lever, a movable contact connected to the control shaft to be moved thereby, and a fixed contact in the path of movement of the movable contact to be engaged thereby, the invention comprising:

• a locking lever pivotally mounted on the control shaft and movable between an "on" position and an "off" position;
• and
• a working surface on the drive lever, the locking lever comprising a first portion to be engaged by the working surface, whereby the working surface moves the locking lever toward its "off" position when the handle moves towards its "off" position, the locking lever comprising a second portion to be moved toward engagement with the toggle joint when the locking lever is moved by the working surface, the second portion of the locking lever being spaced from the toggle joint pin when the working surface of the drive lever first moves the locking lever, whereby there is play between the second portion of the locking lever and the toggle joint pin such that the locking lever can only be pivoted part way and allows only partial movement of the drive lever and the handle attached thereto unless the toggle joint pin moves out of the way of the second portion of the locking lever.