{"product_id":"up-down-folding-window-hardware","title":"Vertical Bi-Fold Window Hardware Kit – Counterbalance Free-Stop Servery Mechanism for Pass-Through Windows \u0026 Bars","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\n\u003cp\u003eThe 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.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFree-Stop Hover Counterbalance:\u003c\/strong\u003e 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).\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eComplete Integrated Mechanism:\u003c\/strong\u003e 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.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMultiple Weight Adaptations:\u003c\/strong\u003e Available in calibrated spring ratings to accommodate various sash sizes and weights:\n    \u003cul\u003e\n      \u003cli\u003e8 kg – 16 kg (Recommended sash weight ~11 kg)\u003c\/li\u003e\n      \u003cli\u003e10.5 kg – 29 kg (Recommended sash weight ~21 kg)\u003c\/li\u003e\n      \u003cli\u003eHeavy-Duty up to 30 kg \/ 66 lbs\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSpace-Saving Bi-Fold Canopy Design:\u003c\/strong\u003e 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.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDurable Engineering Materials:\u003c\/strong\u003e 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.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Vertical Bi-Fold Pass-Through \/ Servery Window Hardware System\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTrack Material:\u003c\/strong\u003e Heavy-Duty Extruded Aluminum Alloy (Anodized Finish)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTrack Length Options:\u003c\/strong\u003e 1.0 m (39.4\") and 1.5 m (59.1\") track sets\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCounterbalance Mechanism:\u003c\/strong\u003e Stainless Steel Constant-Force Spiral Coil Springs\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLoad Capacities:\u003c\/strong\u003e 8KG, 21KG, and 30KG rated spring assemblies (up to 30 kg \/ 66 lbs total window weight)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHinge \u0026amp; Hardware Material:\u003c\/strong\u003e 304 Stainless Steel \u0026amp; Reinforced Engineering Nylon\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaximum Opening Angle:\u003c\/strong\u003e Up to 80° - 90° overhead hover\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFrame Compatibility:\u003c\/strong\u003e Solid wood frames, aluminum alloy profiles, and composite window sashes\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Kitchen pass-through bars, restaurant servery counters, cafe order windows, patio entertainment bars, and interior partition windows\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWholesale \u0026amp; OEM Capabilities\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCustom Track Extrusions:\u003c\/strong\u003e Custom cut lengths and matching surface finishes (matte black, champagne, silver anodized) for window and door fabricators.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSpring Calibration Engineering:\u003c\/strong\u003e Custom spring tension matching for non-standard glass thicknesses and acoustic double-glazed units.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eComplete Hardware Sets:\u003c\/strong\u003e Bulk contractor packaging with full component sets, fasteners, and installation schematics.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFactory-Direct B2B Supply:\u003c\/strong\u003e Direct manufacturing from Ningbo Dimon, strict quality inspection, flexible wholesale tiers, and global ocean freight logistics.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Ningbo Dimon Metal Products Co.,Ltd","offers":[{"title":"1-meter track (one set)","offer_id":47956561559691,"sku":null,"price":155.0,"currency_code":"USD","in_stock":true},{"title":"Folding hover window accessories (30KG)","offer_id":47956561592459,"sku":null,"price":211.0,"currency_code":"USD","in_stock":true},{"title":"1.5-meter track (one set)","offer_id":47956561625227,"sku":null,"price":192.0,"currency_code":"USD","in_stock":true},{"title":"Folding hover window accessories (21KG)","offer_id":47956561657995,"sku":null,"price":189.0,"currency_code":"USD","in_stock":true},{"title":"Folding hover window accessories (8KG)","offer_id":47956561690763,"sku":null,"price":178.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0575\/0295\/7707\/files\/09844f370e32c5abb97ebe6429cadfa9.jpg?v=1790062146","url":"https:\/\/nbdimon.myshopify.com\/products\/up-down-folding-window-hardware","provider":"Ningbo Dimon Metal Products Co.,Ltd","version":"1.0","type":"link"}