The QTZ315 tower crane is a reinforced tower crane designed to meet standards such as GB/T50311 “Tower Cranes” and GB5144 “Safety Regulations for Tower Cranes.” It features a rated lifting moment of 315 t·m and a lifting capacity up to 16 tons, with models including TC7020, TC6524, TC6028, and TC5236. with a maximum lifting capacity of 16 tons. Available models include TC7020, TC6524, TC6028, and TC5236. The hoisting mechanism, slewing mechanism, and luffing mechanism all utilize variable frequency speed control. The electrical control system employs imported components, while safety protection devices are either mechanical or mechatronic products, ensuring comprehensive reliability. This crane supports fixed, traveling, attached, and internal climbing configurations, meeting diverse construction needs for urban mid-to-high-rise buildings, industrial plants, power station dams, bridges, and other structures.

QTZ315 Technical Specifications  

【Hoisting Mechanism】:

    The hoisting mechanism (2200 kg) employs a YZP280M-6-65KW variable frequency motor. The motor drives the reduction gearbox via a splined coupling, which in turn drives the drum. Speed is adjusted via frequency settings on the inverter. Speed control is stepless from 0 to all gear positions, ensuring smooth starts and stops with minimal impact. When using 2 ropes, speeds reach 0~102 m/min and 0~51 m/min; with 4 ropes, speeds reach 0~51 m/min and 0~25.5 m/min.

A normally closed hydraulic push-rod brake (YWZ3H315/90) (850-900Nm) is installed at the input shaft end of the reduction gearbox (see Figure 4-13). A height limiter is mounted on one side of the drum, adjustable to the required height. It offers reliable control, simple operation, and convenient maintenance.

【Rotary Mechanism】】:

     The slewing mechanism is the transmission device that provides power for the upper slewing of the tower crane. This device consists of a motor, planetary reducer, pinion gear, slewing limiter, and other components. This tower crane employs two such devices, symmetrically distributed on both sides of the slewing bearing and mounted on the upper support. Their pinion gears mesh with the large ring gear of the slewing bearing, and the mechanism is driven by a torque motor equipped with a brake.

   The motor tail features a normally closed disc brake, which can be used for tower crane jacking operations and boom braking/positioning during fixed-point work. The slewing limiter restricts the tower crane's rotation to 540° in any single direction to prevent cable breakage. 

【Variable-Angle Mechanism】:

The boom hoist mechanism (470 kg) utilizes a YLEF112L-95Nm torque motor. This motor drives the drum via a planetary gear reducer, enabling the load trolley to traverse the boom at speeds ranging from 0 to 80 m/min through wire rope operation. A disc brake is integrated at the motor tail, providing delayed braking when the trolley motor power is cut off. The boom limit switch prevents misoperation by halting the trolley before it contacts the buffer at the base of the boom.

【Lifting Boom】: The lifting boom consists of 11 sections, with a tie rod lifting point installed on the upper chord of the third, seventh, and eighth sections. Each section is connected via pins. A trolley traction mechanism is mounted on the first section, and a wire rope anti-twist device is installed at the boom tip. The maximum boom length is 70 meters, and it can be assembled into five different lengths: 65 meters, 60 meters, 52.5 meters, and 45 meters, to meet various rotation space requirements. A trolley luffing mechanism is installed on the base section of the boom, along with a walkway frame for convenient installation and maintenance.

【Balancing Arm】: The balancing arm consists of three sections—two 7.5-meter sections and one 4-meter section—connected by pins. Using these pins, the balancing arm and its tie rods form an integrated structure with the rotating tower body and tower top. Guardrails and walkways are installed on both sides of the balancing arm.

【Rotary Limit Switch】:

 【Tower Top】

     The top of the tower is a truncated cone, its upper end connected to the lifting arm and counterweight arm via tie rods to maintain the horizontal alignment of both arms, while its lower end is secured with four pins to

     The rotating tower body connection features a work platform and pulley system at the top of the tower to facilitate the installation of the boom tie rods and counterweight boom tie rods.

【Driver's Cab】    The cab serves as the operator's workstation for controlling the tower crane, fixed to the right side of the rotating tower body. The indicator lights and control handles of the integrated control console are positioned on both sides of the operator's seat, offering convenient operation and a wide field of view.

    The cab electrical control box is located at the rear of the cab, housing the main circuit breaker, lighting circuit breakers, auxiliary circuit breakers, and other devices.

【Electrical Control System and Safety Devices】: 

   The QTZ315 electronic control system employs a state-of-the-art PLC + variable frequency drive control approach, enhancing system reliability.

Significant improvements have been achieved in maneuverability, stability, and machine efficiency. The adoption of variable frequency drives enables each mechanism to achieve

Stepless speed regulation significantly enhances the overall stability of the equipment. The electrical components of this control system are globally sourced: the PLC is from Japan's OMRON, the inverter from Japan's Yaskawa, and the complete low-voltage system from Schneider Electric. This global sourcing substantially reduces the failure rate of the electrical control system while also facilitating fault diagnosis, localization, and troubleshooting. Additionally, the system incorporates electrical safety devices such as anemometers and obstruction lights, alongside mechanical safety features including trolley shaft break protection and traction rope break prevention to prevent runaway vehicles.