PURPOSE: To improve operability by working the action of a lever and gravity, an irregular notch section at 45°, a wire, etc., together and releasing locking by remote control.

CONSTITUTION: A locking fulcrum 3 at the center of a lever-shaped locking arm 2 is used as a fixed fulcrum while the front end of the arm 2 on the cutting side is employed as a cutting-side 45° fulcrum 4, and the front end of the arm 2 on the load side is used as a load-side sliding fulcrum 5. The fulcrum 4 and a shaft-shaped cutting-side sleeper 6 are engaged by a projecting section at 45° and a recessed groove 7, and the cutting side is locked. A dropping-in groove 9 at the time of a pull for dropping in the fulcrum 5 and a dropping-in groove 10 at the time of a pusher are formed to a shaft-shaped load-side sliding sleeper 8. When the sleeper 6 is moved by tension on the cutting side and the fulcrum 4 is pushed up by the groove 7, the fulcrum 5 falls into the groove 9 or the groove 10. The arm 2 loses a balance, and the locking of the sleeper 6 is released. Accordingly, a power supply, etc., are not required at the time of a disaster, and locking can be released instantaneously by remote control.