What are the safety devices for construction lifts?

- Feb 27, 2019 -

Speed limiter

A safety device is provided to prevent the cage of the construction elevator from overspeeding or falling. It is divided into two types: one-way type and two-way type. The one-way speed limiter can only act as a speed limit in the downward direction of the cage, and the two-way speed limiter The speed limit can be applied in the upper and lower directions of the cage. The speed limiter shall perform performance testing according to the specified period.

2. Buffer spring

The buffer spring is mounted on the spring seat connected to the base frame to reduce the impact of the cage when the cage is in a fall accident, and to ensure flexible contact when the cage and the counterweight are lowered to the ground, thereby slowing down the cage and the counterweight when landing The impact. The buffer spring has two types of conical springs and cylindrical coil springs. Typically, each cage has two or three conical springs or four cylindrical coil springs on the corresponding chassis.

3. Upper and lower limiters

In order to prevent the cage from exceeding the required stop position when it is up and down, or the device that is caused by the driver's misoperation and electrical failure, etc., the device is installed on the cage and the rail frame, and the limit device is touched by the limit position. The block and the limit switch are formed, and the highest limit device at the top of the cage can prevent the roof from falling; the lowest limit device at the bottom of the cage can accurately stop the layer, and belongs to the automatic reset type.

4. Upper and lower limit limiters

The upper and lower limit limiters are when the upper and lower limiters are inoperative. When the cage runs beyond the limit switch and the overtravel, the power can be cut off in time to stop the cage. The limit limit is non-automatic reset type. After the action, only manual reset can be performed to restart the cage. The limit limiter is mounted on the cage and rail frame. (Overtravel is the specified safety distance between the limit opening and the limit switch)

5. Safety hook

The safety hook is to prevent the cage from reaching the preset position. The upper limiter and the upper limit stopper cannot be operated in time due to various reasons, and the cage continues to run upward, which will cause the cage to impact the top surface of the rail frame to fall over and fall. The hook shape is also the last safety device. It can make the cage ascend to the top of the rail safety protection facilities, safely ditch on the rail frame, prevent the cage from derailing, and ensure that the cage does not fall over and fall.

6. Emergency stop switch

When the cage is in an emergency for various reasons during operation, the driver can press the emergency stop switch at any time to stop the cage. The emergency stop must be a non-self-resetting safety device, usually installed on the top of the cage.

7. Cage door and protective fence door interlocking device

The cage door and the protective fence door of the construction elevator are equipped with electrical interlock switches, which can effectively prevent the material falling of the personnel caused by the cage or the protective fence door not being closed, only when the cage door and the protective fence are completely It can be started after it is closed.

8. Floor access door

A transportation channel and a passage for people to enter and exit are arranged between the construction elevator and the floor, and a floor access door must be provided at the junction of the passage opening and the construction elevator. The height of the floor access door is not less than 1.8m, and the lower edge of the door is not more than 50mm away from the passage surface. This door is normally closed when the cage is running up and down, and can only be opened by the personnel inside the cage when the cage is docked. Personnel on the floor should not be able to open the door to ensure that the access opening is not dangerous under closed conditions.

9. Communication device

Since the driver's operating room is located in the cage, it is impossible to know the demand situation of each floor and to distinguish which floor is signaled, so a closed-circuit two-way electrical communication device must be installed. The driver should be able to hear the demand signal on each floor.

10. Shelter at the ground entrance

When the construction elevator is safely completed, the protective shed of the ground entrance and exit should be set up in time. The material of the protective shed is made of ordinary scaffolding steel pipe. The length of the protective shed should not be less than 5m. It can be connected with the ground access protection shed. The width should not be less than the outermost dimensions of the elevator bottom cage. The top material can be 50mm thick wood or two layers of bamboo rafts, and the spacing between the upper and lower bamboo rafts should be no less than 600mm.

11. Broken rope protection device

When the wire rope of the cage and the counterweight breaks the rope, the broken rope protection switch cuts off the control circuit and the brake brake stops.