Faulty safety gear
- Causes
- Falling speed did not reach the designated speed level in order to activate the overspeed governor and safety gears
- Failure of overspeed governor to operate although the activation speed was reached
- Jammed due to inadequate clearance (poor installation) or dirty
- Missing / worn off parts
Scratch marks found on the safety gears [20]
- Description of defect
Safety gears that unable to grip the guide rails and hold the car in static position will cause the lift car plunge into the lift pit. Faulty safety gears can be detected if the there is a sign of scratch marks on the safety gears
- Diagnostic/testing method
Safety gears shall be inspected to ensure it is properly installed The safety gears shall be tested out with full load and tripping the governor by hand at rated speed in the down direction (SS550)
- Good practices
Safety gear shall be provided for the lift car and counterweight for the purpose to stop and sustain the car with its rated load in the downward direction, for when the case tripping speed of the overspeed governor.
If the suspension devices break, the safety gears shall grip the guide rails and hold the car in position (SS550).
- Corrections
For elevator car with a speed of 0.75 m/s, instantaneous safety gears may be used, while for elevator above 0.75 m/s, progressive guide clamp type may be used. Instantaneous safety gears may be used for counterweight in the case of elevator with a rated speed below than 1 m/s
Instantaneous safety gears [22]
Progressive elevator safety gear clamp [23]