Principles of application of instantaneous and progressive safety tongs for elevators
If the rated speed is greater than 1m/s, the counterweight (or counterweight) safety clamp shall be gradual and, in other cases, instantaneous. 4. The release of the safety tongs should be done by competent personnel.
If the car is fitted with a number of safety guards, they shall be all progressive.
If the elevator rated speed is greater than 0.63 m/s, the car should adopt progressive safety tongs. If the rated speed of the elevator is less than or equal to 0.63m/s, the car can use instantaneous safety tongs
