Maintenance of safety clamp for elevator speed limiter

Core Tip: Speed limiter safety clamp linkage over-speed protection device, including speed limiter, safety clamp action of electrical protection device and speed limiter rope break or relaxation protection device. Speed limiter safety clamp system is essential for elevators

The safety clamp linkage overspeed protection device of the speed limiter includes the speed limiter, the electric protection device for the action of the safety clamp and the protection device for the breakage or relaxation of the speed limiter rope.

Speed limiter safety clamp system is an indispensable safety device for elevator, when the elevator overspeed, runs out of control or suspension device breaks. When the speed of the car reaches the limit value (generally more than 115% of the rated speed), the speed limiter can send out electrical signals and produce mechanical action to cause safety pliers to work, quickly stop the elevator car on the guide rail, and maintain a static state, so as to avoid casualties and equipment damage accidents.

The following problems may exist in the speed limiter safety clamp device:

(1) Because the speed limiter spring is in the state of repeated expansion for a long time, its setting speed is changed;

(2) The rotating parts are short of oil for a long time, and the resistance increases, which makes the centrifugal swing part not flexible.

(3) Because of the change and extension of the wire rope itself, the tension device touches the ground, which makes the tension of the wire rope insufficient and slips.

(4) Oil shortage and rust in the transmission part of the connecting rod pull arm of safety pliers, which results in the lifting force exceeding 300N.

(5) The distance between the end of the active lever and the safety clamp linkage switch is too large, and when the arm is lifted, the switch can not operate at the same time.

(6) The gap between the wedge and the working face on the side of the guide rail is too large. When the wedge is lifted into the connecting rod, the guide rail cannot be jammed by the wedge.

(7) There is too much oil in the wedge, and the wedge can not be reset after loosening the arm, resulting in damage to the guide rail. The existence of these problems not only makes the system a decoration, but also easily causes psychological paralysis, and the potential harm is greater.

To strengthen the maintenance of speed limiters and safety pliers, the following two points should be done well:

(1) Speed limiters should be inspected regularly. Rotating pin, tensioning device axle and sleeve should be squeezed with calcium-based lubricant once a week. The tension of the tensioning device should be the same. The rotating shaft pin should be oiled once a week and cleaned once a year. The lead seal should not be disassembled. The centrifugal swing device should regularly clean up the oiling and keep its movement flexible. When the length of the speed limiter's rope exceeds the specified range, the rope should be truncated. The speed limiter shall be checked once every two years to ensure that its speed is within the range prescribed by the national standards.

(2) The safety forceps and connecting rods should be lubricated once a month and tightened to ensure that the lifting force is transferred quickly to the safety forceps and rods, and not more than 300N. Adjust loose spring, screw, pin and other parts. Wedge and pliers are coated with a small amount of Vaseline once a month. Regularly clean and adjust the safety clamp wedge, remove the oil deposited in it, and ensure the flexibility of clamp movement.

Car Speed Limiter-Safety Clamp Linkage Test:

(1) Construction supervision and inspection: the car is equipped with the following loads to go down at the maintenance speed and carry out the speed limiter-safety pliers linkage test. The speed limiter and safety pliers shall operate reliably:

(1) Instantaneous safety forceps, the rated load of the car, for the elevator whose car area exceeds the prescribed load, the actual area of the car according to the prescribed rated load as the test load;

(2) Gradual safety forceps, the car loads 1.25 times rated load. For the elevator with the car area exceeding the prescribed load, the larger value of 1.25 times rated load and the actual area of the car according to the prescribed rated load is taken as the test load.

(3) For non-commercial car elevators whose car area exceeds the corresponding stipulations, the car is loaded with 150% rated load.

(2) Periodic inspection: the car is empty and goes down at the speed of overhaul. The speed limiter-safety clamp linkage test should be carried out. The action of speed limiter and safety clamp should be reliable.