What Is a Cordless Spring Unit Device for Child Safe Window Coverings?

The DOSRON cordless spring unit device is a compact, sealed module that hides the lifting
mechanism inside the tube or headrail of the blind. Instead of a cord lock and hanging cord set,
a constant-force stainless-steel spring delivers the lifting force and holds the bottom rail in place.
Users simply pull the rail to the desired height and let go; the spring and brake manage the motion.

By moving the force generation inside the headrail and removing exposed cords, the system helps
OEM brands upgrade traditional products into child safe window coverings with minimal changes to
their existing fabrication processes. The same core can be tuned for:

• Blackout and light-filtering roller shades
• Honeycomb / cellular shades (bottom-up or special configurations)
• Roman shades with guided lift tapes or cords hidden at the back
• Faux-wood or aluminum Venetian blinds with cordless lift functions

Key Features & Benefits

1. Cordless Interface for Child-Safe Rooms

• No front lift cords or bead chains at the window, reducing strangulation risks in nurseries, kids’ rooms and family spaces.
• Supports retailers and brands aiming to meet or exceed ANSI/WCMA A100.1 and EN 13120-style safety expectations.
• Clean visual line without cord clutter, preferred by designers and end users.

2. Constant-Force Spring Balance

• 301 stainless-steel constant-force spring keeps force nearly flat over the full stroke.
• Balanced feel from fully open to fully closed; the blind does not feel “too heavy at the start, too strong at the end”.
• Reduces bounce and impact at the headrail, supporting quiet operation.

3. Sealed, Low-Friction Housing

• POM engineering plastic housing for low friction and stable dimensional accuracy.
• Sealed design keeps dust and debris away from the spring, improving cycle life in real projects.
• Compact footprint suitable for narrow headrails and standard roller tubes.

4. Adjustable Pre-Tension & Weight Ranges

• Module families cover small, medium and heavy shade weights with targeted load windows.
• Installers can add or remove turns of pre-tension to fine-tune balance on site.
• Allows one mechanism family to serve multiple fabrics, tube diameters and bottom rail designs.

5. Quiet, Controlled Movement

• Guided spring path and optional internal braking lower noise levels compared with chain-operated systems.
• Soft approach to top and bottom reduces hard impacts inside the tube or headrail.
• Helps premium programs promote “quiet, child-safe blinds” as a visible upgrade over legacy products.

6. OEM-Friendly Integration

• Adapters for typical tube diameters and headrail profiles (e.g. Ø25 / Ø28 / Ø32 / Ø38 mm).
• Works with standard end caps, brackets and bottom rails used in existing collections.
• Suitable for both stand-alone cordless blinds and hybrid spring + motor concepts.

Technical Specifications (Typical Values)

Values below represent typical design targets for a standard DOSRON cordless spring unit device family.
Final specifications can be customized for specific OEM projects.

System Integration & Hybrid Options

The DOSRON cordless spring unit device can be used either as a stand-alone lift core or as
part of a hybrid spring + motor architecture:

• Stand-alone cordless blinds: Manual lift only, optimized for cost-effective safety upgrades in retail and project markets.
• Hybrid spring + motor rollers: The spring shares the load with a tubular motor, reducing motor torque demand and helping extend motor life.
• Motor-ready headrails: Spring unit positioned in-line with drive tubes or gear sets for future motorization options.

For OEMs already using DOSRON motors, the same lift logic can be aligned with battery-powered tubular motors in 25–28 mm classes, allowing a unified platform for both cordless and motorized window coverings across product lines.

OEM / ODM Support for Cordless Spring Unit Programs

DOSRON works with blind manufacturers, fabricators and brand owners to turn the
cordless spring unit device for child safe window coverings into a complete product program:

• Load charts & selection guidance: Tables and tools that map module models to fabric type, tube size, blind height and bottom-rail weight.
• Custom spring curves: Adjustment of spring thickness, width and number of turns for your key selling sizes.
• Headrail & tube interface design: Drawings and recommendations for brackets, end caps and drive adaptors.
• Child-safety documentation: Engineering statements, drawings and support materials to help with retailer and third-party audits.
• Training & installation support: Installation notes, adjustment guides and troubleshooting tips for field technicians.

FAQs: Cordless Spring Unit Device for Child Safe Window Coverings

Q1. Is the cordless spring unit device certified for child safety?

The mechanism is engineered to support child-safe product designs by removing accessible
front cords and chains. Final certification (e.g. ANSI/WCMA, EN) depends on the complete blind
assembly and local test program, which DOSRON can support with engineering data.

Q2. What blind types can use the same spring unit family?

The same platform can be adapted for roller shades, honeycomb shades, Roman shades and
Venetian blinds, using different interfaces to the tube or headrail while keeping the core
spring logic.

Q3. How do installers adjust the balance on site?

Installers typically adjust pre-tension by rotating the tube or internal arbor a set number of
turns before locking the end cap. More pre-tension supports heavier fabrics; less is used for
lighter blinds. DOSRON provides target turns and procedures for each module size.

Q4. Does the system work with both blackout and light-filtering fabrics?

Yes. As long as total blind weight stays within the recommended load window, the cordless
spring unit device can be tuned for blackout, dim-out and sheer fabrics in the same program.

Q5. How should OEMs get started with sampling?

OEM customers usually begin with a sample kit covering small, medium and heavy modules,
plus suggested adapters for their current tubes and headrails. After initial trials, DOSRON
can refine spring specs and accessories for your main SKUs and markets.