Overview

The Ningbo Dimon Vertical Bi-Fold Window Hardware Kit (Counterbalance Servery Window System) is an engineered architectural hardware set designed for vertical folding pass-through windows in residential kitchen bars, commercial cafes, patio service counters, and restaurant servery openings. Utilizing constant-force stainless steel spiral coil springs, this system provides effortless, finger-touch vertical folding with an arbitrary free-stop hover function—allowing the window sashes to remain stably suspended at any desired opening angle without slipping down or requiring manual prop rods.

Key Features

• Free-Stop Hover Counterbalance: Heavy-duty stainless steel constant-force power springs offset the sash weight, enabling smooth, feather-light opening and arbitrary positioning (stays open at any height up to 80°–90° wide-angle opening).
• Complete Integrated Mechanism: Includes precision-extruded aluminum guide tracks, heavy-duty stainless steel folding hinges, spring-loaded safety latches, hook swivel pivot bars, and nylon slider spring holders.
• Multiple Weight Adaptations: Available in calibrated spring ratings to accommodate various sash sizes and weights:
  • 8 kg – 16 kg (Recommended sash weight ~11 kg)
  • 10.5 kg – 29 kg (Recommended sash weight ~21 kg)
  • Heavy-Duty up to 30 kg / 66 lbs
• Space-Saving Bi-Fold Canopy Design: As the window opens, the dual sashes fold upward to create a sleek overhead awning/canopy that maximizes counter pass-through clearance and unobstructed views.
• Durable Engineering Materials: High-lubricity wear-resistant POM/nylon mounting blocks combined with high-grade stainless steel springs ensure silent glide, zero binding, and long-term cycle durability.

Technical Specifications

• Product Type: Vertical Bi-Fold Pass-Through / Servery Window Hardware System
• Track Material: Heavy-Duty Extruded Aluminum Alloy (Anodized Finish)
• Track Length Options: 1.0 m (39.4") and 1.5 m (59.1") track sets
• Counterbalance Mechanism: Stainless Steel Constant-Force Spiral Coil Springs
• Load Capacities: 8KG, 21KG, and 30KG rated spring assemblies (up to 30 kg / 66 lbs total window weight)
• Hinge & Hardware Material: 304 Stainless Steel & Reinforced Engineering Nylon
• Maximum Opening Angle: Up to 80° - 90° overhead hover
• Frame Compatibility: Solid wood frames, aluminum alloy profiles, and composite window sashes
• Application: Kitchen pass-through bars, restaurant servery counters, cafe order windows, patio entertainment bars, and interior partition windows

Wholesale & OEM Capabilities

• Custom Track Extrusions: Custom cut lengths and matching surface finishes (matte black, champagne, silver anodized) for window and door fabricators.
• Spring Calibration Engineering: Custom spring tension matching for non-standard glass thicknesses and acoustic double-glazed units.
• Complete Hardware Sets: Bulk contractor packaging with full component sets, fasteners, and installation schematics.
• Factory-Direct B2B Supply: Direct manufacturing from Ningbo Dimon, strict quality inspection, flexible wholesale tiers, and global ocean freight logistics.