Cangzhou Yunxinda’s electric retractable grandstand seating adopts standardized modular integrated structure. Every component is independently produced and assembled, featuring stable operation, high bearing capacity and long service life. The whole set can be divided into five core structural parts: load-bearing steel frame, synchronous electric drive system, walking wheel assembly, step platform & flip spectator seats, and full safety protection structure.

1. Heavy-Duty Load-Bearing Steel Frame (Main Skeleton)

The steel frame supports all weight of spectators and other accessories, which determines the overall stability of the grandstand.

Raw material: National standard Q235 rectangular steel tube with uniform wall thickness. Main column: 100×50×3mm; main cross beam: 50×40×2.5mm; auxiliary support beam: 60×40×2mm.

Structural design: Double-layer triangular diagonal bracing structure for uniform force dispersion. Static bearing capacity reaches 500kg per square meter, no shaking or sinking under full load.

Anti-corrosion treatment: Indoor frames go through sand blasting + electrostatic high-temperature plastic spraying; outdoor grandstands add hot-dip galvanized base layer to resist moisture and rust.

Modular design: Each section is connected by high-strength bolts without on-site welding. It is convenient for container transportation, field assembly and later disassembly maintenance. Wall-mounted grandstands are equipped with wall anchor supports to prevent tipping.

2. Synchronous Electric Drive System (Power Core)

This is the unique core structure of electric retractable grandstands, responsible for automatic stretching and retracting of all tiers.

Low-speed high-torque reduction motor

Installed on the first base tier. It converts high rotation speed into strong torsion force to push the whole bleacher. Built-in overload, overheat and short-circuit protection to avoid burnout. Standard input: 220V single-phase power.

Bilateral synchronous chain transmission

A through transmission shaft connects left and right sprocket groups to ensure fully consistent chain speed and displacement on both sides. Sliding blocks connect each frame tier to chains, pulling all tiers to move parallel without skew or jamming. Guide limit grooves restrict lateral deviation.

Intelligent control unit

Dual control modes: wired wall panel + wireless remote controller. The control box reaches IP54 dustproof & waterproof grade, with independent emergency stop button for sudden accidents.

Limit sensor module

Photoelectric sensors are installed at fully-extended and fully-retracted positions. The system automatically cuts off motor power when reaching preset positions to avoid over-stretching or squeezing damage.

Eccentric self-locking mechanical hook

Linked with the transmission chain. The hook automatically locks the whole frame tightly once fully stretched, maintaining stable bearing without continuous motor power supply. It unlocks automatically before retraction.

3. Silent Walking Wheel Base Structure

Every bottom frame tier is fitted with independent walking components to reduce friction during movement.

Large-size PU silent load-bearing casters with built-in bearings, no scratch on PVC, epoxy and wooden gym floors.

Matching brake locking blocks: wheels are locked after full extension to eliminate sliding displacement during matches.

Independent shock absorption brackets reduce running noise when the grandstand stretches or folds.

4. Step Platform & Automatic Flip Seat Assembly

Anti-slip Step Platform

Panel material: 17mm thick wear-resistant multi-layer plywood or patterned aluminum alloy plate with anti-slip melamine surface.

Aluminum anti-collision edging strips on the front of each step to prevent impact damage.

Closed side baffles block sundries from falling into the drive structure and causing jamming.

Standard step size: height 300mm, depth 700mm; customizable dimensions for special venues.

Two Types of Flip Seating Structure

Front-mounted four-linkage flip seats (for basketball gyms)

Four-link mechanical support ensures automatic downward folding when vacant. Folded thickness is only 135mm to save storage space. Seats are one-piece blow-molded virgin UV-resistant PP plastic with honeycomb reinforcement, anti-crack and anti-fade.

Rear-mounted padded spectator seats (for multi-purpose arenas)

Equipped with independent backrest, optional soft cushions and aluminum alloy armrests. Armrests flip synchronously without interference between tiers, providing higher comfort for long-time events. Custom color and logo printing are supported.

5. Full Surrounding Safety Protection Structure

All safety components comply with international sports venue safety standards EN 13200:

Heightened side guardrails and standard fire evacuation aisles (width ≥900mm).

Front anti-drop baffles on each tier to stop people or articles from falling.

Bottom anti-pinch isolation plates to prevent clamping hazards during retraction.

Warning labels pasted on control box and frame surface, marking load limit and emergency operation prompts.

Yunxinda Structural Optimization Advantages

Double triangular reinforced frame greatly improves anti-shake performance compared with ordinary single-layer frames.

Bilateral full synchronous drive avoids common offset and jamming defects of single-side drive bleachers.

Independent mechanical self-locking structure guarantees safety even under power failure.

All core components are self-produced in our Hebei factory, easy to supply matching spare parts for overseas after-sales maintenance.