Quick Summary
L5 Cordless Spring Mechanism
The L5 spring box is an in-headrail lift module designed for faux wood venetian blinds. Using a POM engineering housing,a 301 stainless-steel spiral spring, and a low-backlash polymer gear train,
the mechanism delivers a cordless front view, smooth lifting, stable hold at any position,
low operating noise, and minimal maintenance. It drops into common steel or aluminum
headrails, supports both ladder tape and cord ladder layouts, and suits residential plus
light-commercial new builds or retrofit programs.
Materials Inside the Cordless Spring Mechanism
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POM Housing — The Cordless Spring Mechanism Backbone
- High stiffness and dimensional stability keep gear centers and shafts aligned under load, protecting usable torque.
- Wear and aging resistance supports frequent daily lifting cycles without brittle cracking under normal indoor humidity and temperature changes.
- Low-friction contact surfaces cooperate with tapes and guides to give a smoother, lighter operating feel.
- Injection-molding friendly geometry enables ribs, clips, and mounting holes to be formed in one shot for stable, repeatable volume production.
301 Stainless-Steel Spiral Spring — The Cordless Spring Mechanism Power Core
- High elastic limit delivers a near-linear restoring force over the working stroke, well matched to faux-wood slat weight ranges.
- Low relaxation and good corrosion resistance maintain torque levels in normal indoor moisture and airflow environments.
- Fatigue-optimized winding and heat treatment extend cycle life and keep torque output stable over long-term service.
Polymer Gear Train — The Cordless Spring Mechanism Transmission
- Refined tooth profile and module selection reduce mesh noise and improve mechanical efficiency.
- Reinforced hub and boss design strengthens shaft interfaces and limits wobble growth over years of use.
- Dry-film lubrication path tolerates dust ingress and eliminates the need for oil re-lubrication.
How the Cordless Spring Mechanism Works
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Energy Storage & Release in a Cordless Spring Mechanism
- Lowering: The weight of the slats turns the gear train; the spiral spring is wound tighter, accumulating stored energy.
- Raising: The spring releases stored energy back through the reduction gears to drive the take-up shaft, counteracting gravity so the blind lifts with low effort.
Hold-At-Any-Height Principle in a Cordless Spring Mechanism
Within the rated load range, spring torque plus controlled friction create a balanced condition that lets the blind
remain at any chosen height.
Installers fine-tune using pre-tension turns to stabilize mid-drop behavior and to keep both upper and lower travel limits under control.
Path Consistency in a Cordless Spring Mechanism
- Equal cord path length on both sides of the blind maintains left-right synchronization and stable hovering.
- Compatible with both ladder tapes and cord ladders, enabling cost-effective migration from corded to cordless within existing headrail families.
Compatibility & Scenarios
Window Type & Headrail Fit
- Window type: Faux wood venetian sets (PVC or composite) using ladder tape or cord ladder layouts.
- Headrail: Standard rectangular steel or aluminum headrails; inner channels allow the cartridge to slide in and be fixed at multiple screw points.
Rooms & Projects

- Residential: Living rooms, bedrooms, studies, and children’s rooms.

- Light commercial: Hotels, serviced apartments, meeting rooms, show flats.
Key Benefits
- Cordless safety and clean façade to match contemporary interiors and child-safe preferences.
- Stable torque profile from the 301 stainless spiral spring, giving predictable, repeatable lift characteristics.
- Low-noise drive train thanks to tuned polymer gears and inherent material damping.
- Rigid POM chassis to resist twisting or deflection and protect torque delivery.
- Low maintenance via a sealed cavity and dry-film lubricant, with no routine service needed.
- Fast assembly supported by universal mounting patterns and modular interfaces.
- Batch consistency backed by torque-curve sampling and checks on critical clearances.
L5 Cordless Spring Mechanism Specifications
| No | Loading capacity | Spring spec. | Resistor inside | System | Cords | |
| KG | Part Number | Spring Thickness | Set | |||
| 1 | 4.0-4.49 | L5 | 0.11+0.12 | 1.5 | 1 | 2 |
| 2 | 4.5-4.99 | L5 | 0.12 | 1.5 | 1 | 2 |
| 3 | 5.0-5.49 | L5 | 0.12 | 2 | 1 | 2 |
| 4 | 5.5-5.99 | L5 | 0.13 | 1.5 | 1 | 2 |
| 5 | 6.0-6.49 | L5 | 0.13 | 2 | 1 | 2 |
| 6 | 6.5-6.99 | L5 | 0.14 | 1.5 | 1 | 2 |
| 7 | 7.0-7.49 | L5 | 0.14 | 2 | 1 | 2 |
| 8 | 7.5-7.99 | L5 | 0.15 | 2 | 1 | 2 |
| 9 | 8.0-8.49 | L5*2 | 0.11 | 2 | 2 | 4 |
| 10 | 8.5-8.99 | L5*2 | 0.11+0.12 | 1.5 | 2 | 4 |
| 11 | 9.0-9.49 | L5*2 | 0.12 | 1.5 | 2 | 4 |
| 12 | 9.5-9.99 | L5*2 | 0.12 | 1.5 | 2 | 4 |
| 13 | 10.0-11 | L5*2 | 0.12+0.13 | 1.5 | 2 | 4 |
| 14 | 12 | L5*2 | 0.13 | 1.5 | 2 | 4 |
Durability Strategy of the Cordless Spring Mechanism
- Service life engineered for intensive everyday opening and closing.
- In-process torque-curve sampling, assembly-gap checks, and validation in the target headrail platform.
Why Choose a Cordless Spring Mechanism
- Safer, cleaner façade: No exposed cord loops on the window face, lowering entanglement risk and tidying the visual.
- Retail-friendly: Cordless architecture lines up with modern channel safety policies, helping products pass compliance reviews.
- Low upkeep: Fully mechanical, passive design—no batteries, motors, or controllers that require replacement.
- Predictable user feel: A tuned spring curve and managed friction make operation light, repeatable, and easy to specify.
Cordless Spring Mechanism Sizing Guide
Matching Targets
- Low lift effort, secure holding, and controlled lowering across the specified usage envelope.
Pre-Tension Strategy
- Validate performance at the mid-span holding position.
- For heavier or wider assemblies, select a higher-torque variant or use dual spring modules in parallel.
Cordless Spring Mechanism Installation
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Prepare & Insert
- Confirm headrail bay dimensions and hole pattern; remove burrs and metal chips.
- Slide the L5 cartridge into the allotted bay and align the primary screw holes.
Lock & Align
- Secure the two main screws; check gear mesh quality and freedom of the take-up shaft.
- Ensure equal cord path length on both sides to prevent skew during travel.
Pre-Tension & Test
- Apply the specified number of pre-tension turns and perform the mid-span hold check.
- Fine-tune if necessary, close end caps, and re-verify all fasteners.
A visual installation guide and a pre-tension reference sheet are available to standardize workshop procedures.
Durability & User Feel
Noise Controls
- Optimized tooth layout plus material damping helps suppress high-frequency gear noise.
- The sealed housing limits dust ingress and foreign particles that could cause squeaks.
User Feel
- Target experience: “light to start, even travel, hands-off hold.”
- Suitable for night-time residential use and quiet conference environments.
OEM/ODM
Custom Options
- Housing color and branding (laser marking or foil options).
- Multiple torque bands with selectable reduction ratios.
- Headrail interfaces, holes, and guides tailored to your platform.
- Full kit supply: cartridge, brackets, end caps, take-up shaft, fasteners, and documentation.
Engineering Collaboration
- Provide torque–displacement curves, assembly guidelines, and structured field-feedback loops.
- Clear scale-up path from pilot → pre-production → full mass production.
Use Cases

Residential Upgrades
Converting from corded to cordless delivers an immediate surface refresh and significantly reduces tether-related service calls.
Hotels & Multifamily Projects
Higher-torque setups suit frequent cycling; the sealed module helps extend maintenance intervals.
Channel Acceptance
Cordless styling lines up with safety-focused markets, improving listing acceptance and on-shelf presentation.
FAQ
Q1: Does a cordless spring mechanism require an additional brake?
A1: Within the rated load window, spring torque plus guided friction are sufficient for stable holding. For particularly heavy or wide blinds, specify a higher-torque configuration or twin modules in parallel.
Q2: How should I select the torque band for a cordless spring mechanism?
A2: Share the width × drop, slat density, and ladder layout; we’ll return recommended spec plus pre-tension settings for your build.
Q3: Can this cordless spring mechanism be adapted to other shade types?
A3: The L5 module is tuned for faux wood venetians. For roller, honeycomb, or zebra shades, we recommend dedicated spring architectures for best performance.
Q4: How should we think about life and warranty for a cordless spring mechanism?
A4: Lifetime depends on load matching, installation quality, usage intensity, and environment. Start with prototype field tests; we co-optimize based on real-world data.
Q5: Can you deliver a complete kit together with the cordless spring mechanism?
A5: Yes. We can ship cartridge, brackets, end caps, take-up shaft, fasteners, and manuals in a single carton, ready for line assembly.
Field Insight — Cordless Spring Mechanism in Real Projects
The DOSRON Cordless Spring Mechanism for faux wood venetian blinds combines a POM engineering shell,
a 301 stainless-steel spiral spring, and low-backlash polymer gears to provide cordless lift with smooth motion and
stable hold at any height. Beyond supplying the hardware, DOSRON works as an engineering partner—helping you size
the mechanism correctly, set pre-tension on the line, and move from prototypes to volume production with traceable
quality control.
- Engineering support: Load and sizing calculations, torque-band selection, and pre-tension reference sheets.
- OEM/ODM ready: One-stop customization of interfaces, colors, branding, and kit contents to suit your headrail system.
- Easy to start: Send width × drop, slat material/density/weight, and ladder configuration; we reply with torque-band and pre-tension suggestions and can prepare sample sets.

















