Sany Heavy Industry has officially launched an upgraded "Single-Cylinder Interlock" telescopic system for its SAC series all-terrain cranes. Unlike traditional cranes that use rope or hydraulic cylinder telescoping, high-end all-terrain cranes use a single telescoping cylinder to extend boom sections one by one. A critical safety risk in this design is "false interlocking," where the locking pin sends a signal that it is engaged, but mechanically it is not fully seated, risking boom section sliding during a lift.
The new system introduces a "Double-Redundant Detection" mechanism. In addition to the standard "Proximity Sensor" (inductive sensor) that detects the pin position, Sany has added a "Mechanical Position Switch" inside the pin bore. The ECU compares the signals from both sensors. If the inductive sensor shows "Locked" but the mechanical switch shows "Unlocked," the system triggers an immediate "System Fault" and locks out the telescoping function, preventing operation under false pretenses.
The core engineering innovation is the "Pressure-Dependent Unlock Logic." To unlock a boom section, the telescoping cylinder must align perfectly with the pin hole. The system monitors the "Cylinder Bypass Pressure." If the pressure required to retract the locking pin exceeds the set threshold (indicating the boom is under load and the pin is binding), the system refuses to unlock and automatically adjusts the telescoping cylinder position by millimeters to relieve the binding force. This intelligent logic prevents damage to the locking mechanism and ensures that sections can only be extended or retracted in the correct sequence, significantly enhancing safety in complex lifting scenarios.
