Cordless Spring System Overview for 38ZB Zebra Blinds

The 38ZB spring box is a dedicated in-tube spring module for cordless zebra blinds using 38 mm aluminum tubes.
It belongs to the R38 Cordless Spring System family, where 38RB modules are optimized for roller blinds and
38ZB modules are optimized for zebra (day & night) fabrics. Within this Cordless Spring System, each 38ZB module combines a low-friction POM outer shell with an internal 301 stainless-steel spiral spring that provides near constant lifting force across the stroke.

Internal Architecture: Shaft, Spring Boxes, Brake and Circlips

• Shaft – the “bamboo skewer” core: A precision R38 shaft runs through the center, but with a mechanical profile rather than a bamboo look. It defines the positions for each 38ZB spring box and the brake inside the Cordless Spring System.
• 38ZB spring boxes – the “hawthorns” on the stick: One or more 38ZB modules are threaded onto the shaft in series. Each module adds lifting capacity in the Cordless Spring System, just like adding another hawthorn on the skewer.
• Brake – the tail piece of the skewer: The Brake is central to the shade’s safe and graceful operation. It ensures the shade descends at a steady, elegant pace, preventing rapid falls and guaranteeing reliable performance.
• Circlips – the invisible stoppers: Once the spring boxes and brake are positioned, circlips are locked into the shaft grooves above and below the stack, fixing the positions and preventing movement during operation.
• Aluminum tube – the outer shell: The fully assembled spring set (shaft + 38ZB modules + brake + circlips) is then pushed into a Ø38 mm aluminum tube like a plug, creating a compact, sealed cordless lift core for zebra blinds within the Cordless Spring System.

There are two shaft versions in the R38 system: one designed to hold up to 2 pcs of 38ZB spring boxes, and one that can hold up to 5 pcs. The actual number of spring boxes used is selected according to the zebra fabric weight and bottom rail mass for each blind size.

Key Features & Benefits of the Cordless Spring System

Fabric Length
Fabric Length (Unit: ” /CM)		A	B	C	D	E	F	G	H	I	G	L
		36″	36″	48″	54″	60	64	72	84	86	96	Top 40CM rebound force	Unit
		91.44CM	91.44CM	121.92CM	137.16	152.4	162.56	182.88	213.36	218.44	243.84
ITEM	Spring Spec.	Spring Force
1	0.07*19*4000mm	154	175	200	213	225	234	251	276	280	301	50	g
2	0.08*19*3500mm	212	236	264	279	293	303	322	350			75	g
3	0.09*19*3500mm	272	300	333	350	367	378	400				100	g
4	0.10*19*3500mm	331	362	400	418	437	449					125	g
5	0.11*19*3000mm	436	470	509	529	549						175	g
6	0.12*19*2600mm	570	616	671	698							225	g

Engineered for Zebra Fabrics

• Zebra-specific tuning: The 38ZB module is calibrated for the layered double fabric and typical weight distribution of zebra blinds, improving balance and hold at any position within the Cordless Spring System.
• Modular lift capacity: By combining 1–5 38ZB spring boxes on a single shaft, OEMs can cover a wide range of blind widths and drops without redesigning the mechanism.
• Consistent feel: The constant-force 301 stainless-steel spring delivers nearly uniform lift force, so the blind feels similar at the first pull and at full extension.

Quiet, Cordless Spring System User Experience

• No external cords or chains: The R38 38ZB Cordless Spring System supports fully cordless zebra blinds, reducing entanglement risks and eliminating bead-chain rattling.
• Low-friction POM housing: The POM shell provides self-lubricating contact surfaces, reducing internal friction and helping to keep the lift motion smooth and quiet.
• Brake and damping integration: The R38 brake and controlled spring release help avoid “snap-up” behavior.

OEM-Friendly Platform

• Standardized R38 platform: Share the same shaft, brake and circlip logic between 38RB and 38ZB variants; only the spring box type changes between roller and zebra programs in the Cordless Spring System.
• Inventory simplification: Two shaft types (2-spring and 5-spring) plus a defined set of 38ZB modules allow you to cover most zebra blind SKUs with fewer mechanism SKUs.
• Ready for automation and volume: The sealed module design and clear assembly steps are suitable for high-volume production lines and automated pressing equipment.

Application Scenarios

• Premium living rooms and bedrooms: Smooth, quiet Cordless Spring System zebra blinds that match modern interior design.
• Nursery and family spaces: No exposed cords; compliant, child-friendly hardware when paired with suitable headrails and components.
• Offices and hospitality: Unified R38 platform for large projects that require consistent operation across many windows.
• Smart-ready programs: The same R38 mechanical core can be combined with suitable tubular motors in hybrid designs, sharing the load and improving motor life.

Installation & Fabrication Notes for Cordless Spring System Zebra Blind Manufacturers

• Step 1 – Confirm tube and blind specs: Use Ø38 mm tubes and calculate total load (fabric + bottom rail) for the target zebra blind size.
• Step 2 – Select shaft type: Choose the 2-spring shaft for lighter, smaller blinds or the 5-spring shaft for wider, heavier blinds or denser fabrics.
• Step 3 – Decide the number of 38ZB modules: Based on load charts and your key SKUs, configure the shaft with the appropriate number of 38ZB spring boxes to balance the blind without over-pulling.
• Step 4 – Assemble the spring pack: Thread the 38ZB modules onto the shaft “in series”, add the R38 brake at the tail, then lock their positions using the specified circlip grooves.
• Step 5 – Insert into the tube: Push the assembled spring shaft into the aluminum tube like a plug, mount the corresponding end caps, and integrate into your zebra blind headrail.
• Step 6 – Pre-tension and test: Apply the recommended number of pre-tension turns, cycle the blind several times, and fine-tune pre-tension to achieve stable stop at any height.

FAQ

Q1: Can the 38ZB Cordless Spring System be used for roller blinds?
A1: No. The 38ZB spring box in the Cordless Spring System is tuned for zebra (day & night) fabrics. For roller blinds, DOSRON provides the matching 38RB spring box within the same R38 platform.

Q2: How do I decide how many 38ZB spring boxes to use?
A2: Selection is based on zebra fabric weight, bottom rail mass and blind size. The R38 Cordless Spring System offers shafts for up to 2 or 5 spring boxes; your final configuration should follow DOSRON’s load chart and your key SKUs.

Q3: Is the Cordless Spring System child-safe?
A3: The R38 Cordless Spring System eliminates external lift cords and chains at the user interface, helping brands design child-safe cordless zebra blinds. Final compliance still depends on the complete blind design and local regulations.

Q4: Can DOSRON customize the Cordless Spring System for my zebra blind range?
A4: Yes. DOSRON can adjust spring specification, pre-tension range and shaft configuration within the Cordless Spring System to match your target fabric weights, sizes and market requirements for OEM/ODM projects.

Q5: Can I combine the Cordless Spring System with a tubular motor?
A5: The 38ZB Cordless Spring System can be used in hybrid spring + motor architectures, where the spring shares the lifting load with a tubular motor to reduce torque demand and improve motor life.

Q6: What maintenance does the 38ZB Cordless Spring System require?
A6: The 38ZB spring box is a sealed POM module and normally does not require lubrication in use. Routine checks should focus on the overall blind: tube connection, end caps, brackets and correct pre-tension settings.