What is a construction elevator?

Definition of construction elevator: construction elevator, also known as construction hoist, outdoor elevator, passenger and cargo elevator, is the construction machinery often used for carrying people and goods in buildings, mainly used for the construction of internal and external decoration, bridge, chimney and other buildings of high-rise buildings.

Model identification of construction elevator:

For example, "SC200 / 200" means: the ordinary construction elevator with rack and pinion as transmission mode, the rated load of each cage is 2000kg. This paper takes SC200 / 200 as an example.

Construction elevator is composed of five parts: foundation, steel structure, driving device, safety device and electrical system.

Components of construction elevator:

1、 Buffer device

Function: the buffer spring is installed on the spring seat connected with the base frame, so as to reduce the impact of the cage in case of falling accident, and ensure the flexible contact between the cage and the counterweight when it lands, so as to slow down the impact of the cage and counterweight when landing on the ground.

Standard practice: there are two or three conical coil springs or four cylindrical spiral springs on the corresponding underframe of each cage.

2、 Electrical safety switch

1. Electrical interlock limit switch

Function: travel switch, also known as limit switch, is used to control the travel and limit protection of mechanical equipment. It is an electrical appliance that switches circuits according to the travel position of moving parts.

Principle: one group is normally open, one group is normally closed.

Inspection method: open the door and power off.

2. Limit switch

Function: cut off the main power supply.

Principle: the power can be cut off when the connecting rod is moved up and down. When the upper and lower limits fail, one end acts on the limit iron on the standard section to cut off the power supply. It is an emergency stop switch and cannot be reset automatically.

Inspection standard: switch up and down, power off and stop operation.

3、 Mechanical interlock

Mechanical lock hook of safety door of peripheral fence;

Electrical interlock switch of safety door of peripheral fence;

Standard practice: under normal circumstances, the fence door of construction elevator shall be equipped with mechanical lock hook and electrical interlocking limit switch.

Inspection method:

1. Observe whether there is a mechanical lock hook on the fence door. If there is no mechanical lock hook, the safety device is missing.

2. When the fence door is opened during the operation of construction elevator, if the fence door can be opened, the mechanical lock hook will be invalid; if the cage cannot stop running when opening, the mechanical lock hook and electrical interlock limit switch will be invalid.

Mechanical interlock switch of cage door;

Mechanical lock hook of double door inside the cage door;

Electric interlocking limit switch of cage door;

Standard practice: under normal conditions, the cage door of construction elevator shall be equipped with mechanical lock hook and electrical interlocking limit switch.

Inspection method:

1. Observe whether there is a mechanical lock hook on the cage door. If there is no mechanical lock hook, the safety device is missing.

2. If the cage door (the side close to the fence door) can be opened during the operation of the construction elevator, the mechanical lock hook will be invalid; if the cage door and cage double door can not be opened, the mechanical lock hook and electrical interlocking limit switch will be invalid.
 

4、 Falling safety device

Definition: also known as speed limiter, refers to non electrical, pneumatic and manual control of mechanical safety devices to prevent cage falling.

Function: anti falling safety device is the most important safety device of construction elevator, which is installed inside the cage. Its function is to limit the over speed running of the cage. When the cage falls down due to the fault, the anti falling device will start to work and increase the torque. It will brake the cage stably within a certain distance to prevent the cage from falling and ensure the safety of personnel and equipment.

Standard practice: service life of anti falling safety device: 5 years, compulsory scrapping; must be tested and calibrated once a year.

Inspection method: the fall prevention test must be conducted once a quarter to check whether the detection date of the falling protector has expired.
 

5、 Overload protector for construction elevator

Definition: the shaft pin sensor is installed at the connection between the cage and the driving plate (connecting the pin shaft). The weight of the shaft pin sensor is slightly deformed by the weight of the cage to measure the weight, and the weight signal is transmitted to the weight limiter after conversion.

Function: when the elevator is overloaded, it can give an alarm to the driver of the lift. When the limit weight is reached, the circuit will be cut off and cannot be started.

Standard practice: generally, the display screen can display the corresponding readings according to the load capacity.

Inspection standard: overload start.

There are two general types of safety hooks: cast steel plate and integral steel plate. The structure is divided into two parts: the bottom plate and the hook body. The bottom plate is fixed on the column of the construction elevator cage by bolts.

Function: it can make the cage hook on the guide rail frame safely when it goes up to the top of the rail frame safety protection facilities, so as to prevent the cage from breaking away from the guide rail frame or the output gear of the anti falling safety device from the rack, so as to ensure that the cage will not overturn and fall.

Inspection standard: check whether the construction elevator is equipped with safety hook, and it is required to set at least one pair, and check whether the safety hook is stable and reliable.

7、 Other safety measures

1. Emergency stop switch

Definition: in case of emergency due to various reasons during the operation of the cage, the driver can press the emergency stop switch at any time to stop the operation of the cage.

Function: emergency brake.

Inspection method: press the emergency stop button and observe whether the elevator stops running.

2. Floor pager

Definition: a closed-circuit two-way electrical communication device is installed to enable the driver in the cage of the construction elevator to receive the call information from each floor.

Function: floor call information transmission.

Inspection method: press the pager button on the floor to observe whether the driver in the cage can receive information.

3. Floor protective door

Definition: the floor access door set at the joint of the passageway for transporting materials and people and the construction elevator.

Function: during the operation of the construction elevator, the personnel in the floor cannot open the door.

Standard practice: the height of the landing door should not be less than 1.8m, the width difference between the width and the cage door should not be greater than 120mm, the horizontal distance between the landing door and the closed cage door should not be more than 200mm, and the distance from the lower edge of the landing door to the passage should be less than 50mm (see safety regulations for construction hoist gb10055-2007 for details).

Inspection method: check whether the size and position of the floor protective door meet the requirements.
 

Construction elevator is an important vertical transportation lifting equipment in the construction of medium and high-rise buildings. It is usually used in the middle and late stages of construction. It undertakes the work of construction personnel and material transportation, and plays a vital role in reducing labor intensity and improving construction efficiency.