Home / Cases / Batch Delivery of 25.8m Large-span QS70 (35+70+35) Triple-trolley Overhead Cranes for Heavy Equipment Workshop
Batch Delivery of 25.8m Large-span QS70 (35+70+35) Triple-trolley Overhead Cranes for Heavy Equipment Workshop
Nation:China
A leading domestic manufacturer of heavy-duty complete equipment built a new general assembly workshop with a span of 25.8 meters, mainly responsible for the assembly of large pressure vessels, heavy construction machinery main units and ultra-long segmented components.
A leading domestic manufacturer of heavy-duty complete equipment built a new general assembly workshop with a span of 25.8 meters, mainly responsible for the assembly of large pressure vessels, heavy construction machinery main units and ultra-long segmented components. Workpieces feature a wide weight range, including 70-ton heavy main structures and 35-ton auxiliary components on both sides. Single-trolley overhead cranes cannot realize synchronous alignment and assembly, while the coordinated operation of multiple independent cranes easily causes equipment collision, unbalanced stress and substandard assembly accuracy. After multiple rounds of technical demonstration and on-site workshop investigation, the enterprise selected Henan Dafang Heavy Machinery for batch customization of QS70 synchronous triple-trolley overhead cranes. Equipped with three independent lifting trolleys (35t+70t+35t), the crane supports single-trolley operation, dual-trolley linkage and triple-trolley synchronous hoisting, perfectly adapting to the assembly conditions of ultra-long and asymmetric heavy components. Dafang’s technical team specially optimized the structural rigidity of the 25.8m large-span main beam, multi-trolley synchronous variable-frequency control system and high-frequency heavy-duty performance. The whole batch of non-standard triple-trolley lifting equipment was manufactured within 75 days. All cranes were delivered to the factory in batches, passed full-load joint commissioning and synchronous precision verification, and completed workshop safety acceptance in one pass before being officially put into operation on the heavy equipment general assembly production line.
Project Execution & Solution Overview
Dafang provided customized batch QS70 triple-trolley synchronous overhead cranes for the heavy equipment workshop. Key project solutions are as follows:
Working Condition Survey & Customized Equipment Selection
After multiple rounds of technical demonstration and on-site workshop investigation, the enterprise selected Dafang Heavy Machinery for batch customization of QS70 synchronous overhead cranes. The 35t+70t+35t triple-trolley configuration supports single-trolley, dual-trolley and triple-trolley synchronous hoisting, perfectly adapting to the assembly of ultra-long and asymmetric heavy components.
Optimization for Large-span & Multi-trolley System
Targeting the 25.8m large-span beam rigidity, multi-trolley variable-frequency synchronous control and high-frequency heavy-duty operation, Dafang implemented targeted structural and electrical optimization to eliminate span deflection, asynchronous operation and low assembly accuracy.
75-day Efficient Batch Production of Non-standard Equipment
The whole batch of non-standard multi-trolley cranes was completed within a 75-day manufacturing cycle. Modular production and unified non-destructive testing ensure consistent performance and high stability of all batch equipment.
One-time Commissioning & Formal Production
All equipment was delivered in batches and passed full-load joint debugging and synchronous precision calibration. The cranes successfully completed workshop safety acceptance in one pass and were officially put into the heavy equipment general assembly production line.
The crane adopts a widened and thickened box-type double-girder structure. Main girders and end carriages are made of Q355NL high-toughness low-alloy steel plates with optimized camber design for the 25.8m large span. The main beam deflection is strictly controlled within national standard limits during synchronous full-load operation of three trolleys. All load-bearing welds pass 100% ultrasonic non-destructive testing. Designed with A7 high working class, the crane supports 24-hour uninterrupted heavy-duty assembly operation. The whole machine adopts Dafang’s industrial yellow heavy-duty anti-corrosion finish and three-layer epoxy zinc-rich coating for long-term rust prevention in dusty and welding fume workshop environments. Full-length maintenance walkways and protective guardrails on the main beam facilitate synchronous maintenance of multiple trolleys.
35+70+35 Independent Trolleys for Multi-mode Synchronous Lifting
The crane is equipped with three independent lifting trolleys (35t on both sides and 70t in the middle), supporting four flexible operation modes: ① single-trolley independent lifting for small workpieces; ② synchronous lifting of symmetric components by two 35t trolleys; ③ independent lifting of heavy main workpieces by the 70t middle trolley; ④ linkage hoisting of ultra-long asymmetric segmented components by three trolleys. Adopting high-precision variable-frequency synchronous algorithm, the lifting and travelling synchronous error of multiple trolleys is controlled within 2mm, ensuring no workpiece distortion or offset during ultra-long equipment assembly. It greatly improves the assembly accuracy of large pressure vessels and engineering machinery assemblies and eliminates manual auxiliary positioning procedures.
Multi-trolley Linkage Safety Electric Control System
The integrated IP65-grade variable-frequency control cabinet is dust-proof and welding-fume-proof with built-in heat dissipation and dehumidification modules. The three trolleys adopt independent driving and share a unified linkage control system, equipped with complete interlock protection including infrared anti-collision limit, travel limit, overload limit, height limit and emergency stop. The system realizes automatic deceleration and locking in case of trolley overload or excessive proximity, completely avoiding multi-trolley collision accidents. Supporting dual operation modes of cab centralized control and ground wireless remote control, the central control panel enables intuitive switching of single/dual/triple synchronous modes with simple logic, adapting to the operating habits of workshop assembly teams.
Batch Modular Design for Efficient Delivery and Maintenance
The batch-supplied triple-trolley overhead cranes adopt a standardized modular structure with interchangeable main beams, trolleys and electrical control units, reducing later spare parts reserve costs. Multiple independent cable trolleys are adopted with separate cable layout for the three trolleys, ensuring synchronous movement without cable pulling or winding. High-strength wear-resistant pulley blocks and steel wire ropes are configured to adapt to long-term alternating stress of multi-trolley operation and extend the overall service life of the equipment.
On-Site Delivery & After-Sales
The batch of QS70 triple-trolley overhead cranes are transported to the heavy equipment factory in separate modules including main beams, three sets of lifting trolleys and electrical control assemblies. Our professional installation teams conduct synchronous assembly, track calibration, synchronous program joint commissioning and triple-trolley full-load synchronous testing for multiple devices. Complete inspection documents including steel material reports, non-destructive testing certificates, multi-trolley synchronous precision test reports and full-load acceptance certificates are delivered to support special equipment filing.
Special training is provided for workshop operation and maintenance teams, covering multi-trolley synchronous lifting procedures, regular detection standards for large-span main beams and maintenance key points of multi-group variable-frequency systems. 7×24-hour full-cycle remote technical support and sufficient original core accessories such as trolley reducers, frequency converters and synchronous controllers ensure uninterrupted assembly production of the heavy equipment workshop.
Summary
The batch-delivered QS70 (35+70+35) 25.8m large-span triple-trolley overhead crane is a special synchronous lifting equipment developed by Dafang Heavy Machinery for the general assembly workshops of heavy equipment, pressure vessels and construction machinery. With three core advantages of large-span high-rigidity main beam, multi-mode synchronous trolleys and multi-layer anti-collision safety electric control, it perfectly solves the industry pain points of difficult assembly alignment and insufficient single-trolley load for ultra-long asymmetric heavy components.
Dafang Heavy Machinery can customize multi-tonnage and multi-trolley synchronous overhead cranes for heavy equipment, pressure vessel and steel structure manufacturing enterprises, supporting non-standard span and multi-group trolley load customization. We provide one-stop services including on-site workshop survey, synchronous lifting scheme design, batch production, on-site batch installation & commissioning and professional operator training. Customized solutions and quotations are available for all collaborative lifting equipment demands in heavy assembly industries.
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