Quick Summary
The Cordless Spring Drive is a 38mm internal spring mechanism engineered for
manual cordless zebra blinds. Built around a constant-force Spring Box and a controlled
Brake, it replaces cord lifting with a pre-tensioned force-balance architecture that
improves safety, delivers stable positioning, and scales across OEM SKUs by combining multiple Spring Boxes on one
Shaft.
- Child-safe, minimalist cordless design (no exposed cords)
- Modular build: up to 5 Spring Boxes per Shaft
- Pre-winding with Pin for controlled stored energy
- Selection by load + drop using a spring selection table
Cordless Spring Drive Product Overview
A Cordless Spring Drive is not a “cord-removed” zebra blind. Once cords are eliminated, the blind becomes a
hidden force-balance system inside the tube. This 38mm platform is designed for OEM production where
consistent hand feel, controlled stopping, and predictable configuration matter more than showroom-only smoothness.
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Target customers
Zebra blind manufacturers, OEM fabricators, and system integrators.
Application
Manual cordless zebra blinds (day & night blinds).
Cordless Spring Drive System Architecture
The 38mm internal assembly uses five functional modules with clear responsibilities—so performance is engineered, not guessed.
| Component | Role in the system |
|---|---|
| Spring Box | Core energy module with internal 301 stainless steel constant-force spring output. |
| Brake | Provides controlled holding and prevents sudden drop (anti-free-fall protection). |
| Shaft | Structural carrier and alignment backbone; supports multiple Spring Boxes in one tube. |
| Circlip | Fixes the Spring Box and Brake position to maintain consistent geometry and stability. |
| Pin | Locks the system after pre-winding, securing stored energy before insertion into the tube. |
The Pin locks the pre-tension state, which is essential for consistent lift and hold behavior.
Spring Box Engineering Inside the Cordless Spring Drive
The Spring Box defines the force band of the entire mechanism. The Brake governs motion
inside that band—but it cannot “fix” an incorrect band. That’s why proper spring selection is the foundation of stability.
Materials & Construction
- POM housing: self-lubricating, dimensionally stable, and low-noise during long-term cycling.
- 301 stainless steel spring strip: rolled constant-force architecture for near-flat output.
Modular Scaling: Cordless Spring Drive Configuration for OEM SKUs
One Shaft supports up to five Spring Boxes, enabling a scalable platform across different
zebra fabrics, bottom rails, and size ranges. OEM teams can standardize the tube architecture while tuning performance by
adjusting Spring Box model and quantity.
Why modular matters
Fewer unique parts, broader SKU coverage, and faster engineering iteration.
What changes per SKU
Spring Box model + quantity, based on measured load and required drop.
Cordless Spring Drive Model Logic & Selection Principles
The 38mm series includes six Spring Box variants, most visibly differentiated by spring strip thickness. Thicker strips
deliver more force, but allow fewer windable turns in a fixed volume—reducing maximum supported drop.
Model Example
38ZB-08-350-84″
| Code | Meaning |
|---|---|
| 08 | Spring strip thickness: 0.08 mm |
| 350 | Load capacity per Spring Box: 350 g |
| 84″ | Maximum supported blind drop: 84 inches |
Selection Logic (Engineering Rule of Thumb)
- Thicker spring strip → higher force, fewer turns → shorter drop range
- Thinner spring strip → lower force, more turns → longer drop range
Overpowered setups can increase stress on the Brake and raise noise risk.
Cordless Spring Drive Selection Table Placeholder
Use measured fabric + bottom rail weight and required drop to choose the Spring Box model and quantity per Shaft.
Final values are typically confirmed by sample build testing.
| Drop length | Spring Spec. | Spring Force | Rebound Force | |
| 162.56cm | 64″inch | 0.07*19*4000mm | 165g | 50g |
| 0.08*19*3500mm | 260g | 75g | ||
| 0.09*19*3500mm | 330g | 100g | ||
| 0.10*19*3500mm | 430g | 125g | ||
| 182.88cm | 72″inch | 0.07*19*4000mm | 175g | 50g |
| 0.08*19*3500mm | 280g | 75g | ||
| 0.09*19*3500mm | 350g | 100g | ||
| 213.36cm | 84″inch | 0.07*19*4000mm | 185g | 50g |
| 0.08*19*3500mm | 300g | 75g | ||
| 218.44cm | 86″inch | 0.07*19*4000mm | 190g | 50g |
| 243.84cm | 96″inch | 0.07*19*4000mm | 200g | 50g |
Advantages of the Cordless Spring Drive Platform
- Purpose-built for zebra blinds (manual cordless application)
- Safety-driven design: no exposed cords, reduced free-fall risk
- Modular scalability: up to 5 Spring Boxes per Shaft
- Stable force output across travel when correctly selected
- Controlled stopping through Brake authority within the force band
- OEM-friendly configuration by load-based selection
Applications
- Residential manual cordless zebra blinds
- Child-safe window covering product lines
- OEM private-label zebra blind platforms
FAQ – Cordless Spring Drive (OEM Focus)
Q1: Is this Cordless Spring Drive suitable for motorized zebra blinds?
No. This system is engineered for manual cordless zebra blinds. Hybrid motor-spring platforms use different control logic.
Q2: How many Spring Boxes should I use?
It depends on measured fabric + bottom rail weight and required drop. Use the selection table to choose model and quantity per Shaft.
Q3: Why is pre-winding required before installation?
Pre-winding stores initial energy so the system enters the intended force band immediately. The Pin locks the pre-tension state.
Q4: Can a stronger Brake solve drift if the spring is mismatched?
Not reliably. The Spring Box defines the force band; the Brake only governs motion within it. Correct selection comes first.
Q5: Can different Spring Box models be mixed on one Shaft?
Yes, but only with proper load calculations to keep force distribution stable across the full travel.
Q6: Why use POM for the Spring Box housing?
POM offers low friction, dimensional stability, and lower noise potential during long-term cycling versus common plastics.
Q7: What is the role of the Circlip?
The Circlip fixes geometry between the Spring Box and Brake to prevent shifting that can cause instability or inconsistent feel.
Q8: Is this platform suitable for larger / heavier zebra blinds?
Yes—within the boundaries of correct spring model and quantity selection. Modular scaling supports heavier builds when properly configured.
Final Note / Practical Takeaway:
A zebra blind without cords is not a simplified product—it becomes a force-balance mechanism. A well-built
Cordless Spring Drive is engineered so the force band stays stable and the Brake can govern motion predictably.
- Spring Box sets the force band (energy output)
- Brake controls motion and anti-drop behavior within the band
- Shaft maintains alignment and supports modular scaling (up to 5 Spring Boxes)
- Pre-winding + Pin establishes stored energy before tube insertion
- Correct selection (load + drop) drives long-term stability more than friction tuning
