Views: 4 Author: Site Editor Publish Time: 2025-04-22 Origin: Site
In the realm of construction engineering, construction hoists play an indispensable role as vertical transportation equipment, facilitating the efficient movement of personnel and materials in high-rise building construction, bridge construction, and other large-scale projects. This article delves into the structure and working principle of construction hoists to provide a comprehensive understanding of this vital machinery.
The cage is the core component of the construction hoist, serving as the carrying structure for personnel and materials. Traditional cages often had high material and welding requirements, which not only increased production costs but also raised the risk of errors during manufacturing. To address these issues, modern construction hoists have adopted new cage designs. For instance, based on the technical defects of the traditional SC200 cage, a new cage design scheme was proposed. Through finite element analysis under uniform and partial load conditions, the safety of the new cage was verified. This new cage not only reduces welding difficulty but also saves materials while ensuring operational safety.
The guide rail frame provides the vertical running track for the cage. It is composed of top sections, bottom frames, and standard sections. The top section is equipped with guide pulleys, and the bottom frame is connected to the foundation. Standard sections, installed with racks, are bolted together to form the guide rail frame, which is fixed to the building through wall-attached frames. Taking a 70m high construction hoist as an example, finite element analysis and optimization of the guide rail frame were conducted. By optimizing the rail frame under more dangerous conditions to minimize mass, the safety of the optimized rail frame was verified, and the quality was reduced by 14.1%, effectively saving manufacturing costs.
The transmission system is the power source of the construction hoist, typically consisting of a motor, reducer, brake, gear, and other components. In gear-rack-driven construction hoists, the motor generates driving torque, which is transmitted through the coupling, worm gear, worm wheel, and gear to the rack. Since the rack is bolted to the guide rail frame, which is fixed to the bottom frame and foundation of the construction hoist, the rack cannot move up or down. The rotating gear moves up or down along the pitch circle tangent direction of the gear-rack meshing transmission, causing the cage to move up or down. Due to the small size and space-saving nature of the worm gear reducer, it is often arranged inside the cage for easy maintenance. The brake in the transmission system is usually a friction plate brake installed at the tail of the motor, and some construction hoists also use electromagnetic brakes.
The safety protection system is crucial for ensuring the safe operation of the construction hoist. It includes various safety devices such as anti-fall safety devices, rope-breaking protection devices, interlocking control switches, travel and limit control switches, buffers, and emergency stop switches. The anti-fall safety device is the most important safety device in the construction hoist, limiting the running speed of the cage to prevent it from falling and ensuring the safety of personnel and equipment. The rope-breaking protection device is a safety device that instantly brakes when the lifting wire rope breaks. The interlocking control switches ensure that the cage can only start when the doors are fully closed, and the travel and limit control switches automatically cut off the control circuit or power circuit when the cage reaches the travel end or exceeds the limit.
When the operator presses the start button on the control system, the motor starts to run. The reducer converts the high-speed rotation of the motor into a speed suitable for lifting movement and transmits the signal to the lifting system through the controller. Under the action of the driving system, the wire rope starts to tighten or loosen, driving the lifting platform to move vertically up or down. Sensors continuously detect the position of the lifting platform and feed the signal back to the controller to ensure the accuracy and stability of the lifting movement.
During operation, the cage moves along the guide rail frame under the driving force of the transmission system. The guide wheels on the cage ensure that it does not deviate from the guide rail and moves smoothly. The load on the cage, including personnel and materials, is balanced by the counterweight in gear-rack-driven construction hoists, reducing the output power of the main motor and saving energy.
When the lifting movement reaches the predetermined position, the operator can press the stop button on the control system to stop the lifting movement. In emergency situations, the brake will quickly stop the construction hoist to prevent accidents.
Construction hoists have a series of safety measures to ensure the safety of operators and passengers. For example, the safety door can only be opened when the cage is at the bottom position, and the limit switch monitors the lifting height of the cage to prevent it from exceeding the rated height. The overload protection device monitors the load of the construction hoist to ensure it operates within the rated load.
In conclusion, the construction hoist is a complex and important vertical transportation equipment in construction engineering. Its well-designed structure and reliable working principle ensure the safe and efficient transportation of personnel and materials, greatly improving the construction efficiency and quality of high-rise buildings and other large-scale projects. With the continuous development of technology, construction hoists will continue to evolve and innovate to meet the increasing demands of modern construction.
