Unique Two-Stage Anti-Side-Load Design
A “fixed inner rod, telescoping outer sleeve” dual-tube configuration is employed. The small-diameter inner cylinder handles axial thrust and pull, while the large-diameter outer sleeve absorbs the off-center lateral loads from the segment. This effectively separates bending moment from thrust force, greatly reducing bending stress on the inner rod. Even when the segment is grasped off-center, the cylinder lifts smoothly without binding or plastic deformation.
High-Rigidity Long-Stroke Guiding System
An extended guide bushing with wear-resistant guide bands is fitted on the large piston rod exterior, and multi-point support with precision fit is maintained between the two stages. At full extension of up to 3000 mm, excellent buckling stiffness and straightness are preserved, ensuring accurate segment placement and tight, flush ring joints.
Integrated Counterbalance Valve for Safe Holding
A standard high-flow counterbalance valve or dual pilot-operated check valve allows the segment to be safely stopped and locked at any height. Even if a hose bursts or the system is depressurized, the segment will not free-fall, guaranteeing the safety of assembly personnel and equipment below.
Ultra-Low Breakaway for Precision Placement
The main seal uses a filled PTFE and polyurethane low-friction combination with specialized guide rings, achieving breakaway pressure of only 0.25 MPa. Segment lifting micro-motion is sensitive, stick-slip free, and judder-free, allowing operators to finely adjust segment position and attitude for high-quality ring assembly.
Specialized Waterproof Sealing System
To cope with high humidity, dripping water, and slurry in the tunnel, the guide bushing exterior is fitted with multiple wipers, a stainless steel retainer ring, and a drainage groove. The piston rod features a dense hard chrome layer (HV900–1100), thoroughly blocking moisture and dust ingress to prevent seal failure and guide bushing corrosion.
Full Anti-Corrosion Protection
External surfaces are coated with moisture-resistant epoxy. The piston rod is available with hard chrome, Ni/Cr alloy plating, laser cladding, or ceramic thermal spray. All fasteners are stainless steel, adapting to the humid, weakly acidic groundwater environment of long tunnels.
Flexible Mounting & Maintenance-Free Pivots
Clevis, flange, and other connection options are available, with port sizes and positions customized to the erector arm structure of any shield brand. Pivot points are equipped with standard self-lubricating composite bushings, eliminating daily greasing while providing long wear life.
