Adjustable Twin Sash Open-in Casement Window System

Kingbo, as a professional manufacturer of the Adjustable Twin Sash Open-in Casement Window System from China, delivers the only hardware solution on the market that actively solves structural sagging rather than just compensating for it. This system is specifically engineered for French casement (flying mullion) windows, where two sashes open inward without a central post.

Why Standard Hardware Fails on Inward-Opening Double Sash Windows

Most standard hinges cannot maintain precise alignment over time when supporting two independent sashes (glass + screen) within a single frame. The result: jamming, air leakage, and mid-seam misalignment. Kingbo's engineering directly addresses these failures.

The “100% Unobstructed Panoramic French Casement” Advantage

Zero-Mullion Design: Our system enables both sashes to open inward simultaneously with no central vertical post. This creates a complete, uninterrupted glass opening for maximum light and panoramic views.

Precision Dual-Sash Coordination: It ensures the glass sash and screen sash operate independently without friction, even in limited frame space.

Application: Ideal for French window fabricators and European-standard system houses demanding wide, clear sightlines.

Solving the Mid-Seam Alignment & Air Leakage Problem

Industry Pain Point: Over time, gravity causes the active sash to sag, misaligning the center lock seam.

Kingbo Solution: True “adjustable” functionality. The heavy-duty inward-opening hinges allow fine-tuning of the sash position vertically and laterally after installation. This compensates for frame settling or thermal expansion.

Multi-Point Compression Sealing: The main and auxiliary sashes feature a specialized locking interface. When closed with the multi-point cam lock, compression increases, achieving typhoon-resistant air tightness and high acoustic attenuation (tested for noise reduction).

Product Specifications Table

Customization Service (OEM)

Free OEM Design: We adjust hinge specifications and lock styles based on your profile drawings.

Small MOQ Flexibility: Lead time within 15 days.

Packaging: 1 pc/poly bag; 2 sets/inner box; 10 boxes/carton.

For the ultimate French casement window that does not leak, sag, or block the view, the Adjustable Twin Sash Open-in Casement Window System is the only hardware solution that aligns with European engineering standards and Kingbo’s 15-year manufacturing expertise.

How to Avoid Jamming Issues?

Even the best hardware fails if installation is incorrect. If jamming occurs after installation, follow this Kingbo protocol.

Step-by-Step Resolution Guide

Verify Installation Alignment: Check the heavy-duty inward-opening hinges (glass sash) and screen sash hinges for correct mounting angles. Ensure lock boxes and square shaft handles are deviation-free.

Inspect Transmission Components: Confirm no looseness in it’s linkage.

Re-check Profile Compatibility (Most Critical): If jamming persists, the core issue is likely insufficient adaptability between accessories and your profile structure. Re-submit profile drawings to Kingbo’s after-sales team for a re-evaluation of the adaptation plan.

Proactive Engineering by Kingbo

Before Shipping: Kingbo engineers verify that screen sash hinges match the limited space of your profile.

During Installation: Standard procedures require no major frame modification; assembly is clear and fast.

Long-term Reliability: The Adjustable Twin Sash Open-in Casement Window System has passed tens of thousands of opening and closing tests in our lab (certified data). Each accessory’s service life far exceeds ordinary hardware.

Why Global Fabricators Choose Kingbo

Let our engineers configure the precise Adjustable Twin Sash Open-in Casement Window System for your next French window or European-standard project. Since 2009, Kingbo has operated under the founder’s principle: “keeping the faith and firming its commitments.” We are not a trading company; we are a comprehensive manufacturer with 100+ patents, strategic partnerships with real estate enterprises, and trademarks in 36 countries.