A flat spring for roller blind mechanisms, supplying the retraction force that pulls the fabric back onto the tube. Because the force must stay even from fully down to fully up, this is a constant force application rather than a conventional spring one.
A helical spring would make the blind heavy at the bottom and snap it shut at the top. A flat constant force design avoids both.
Force and stored length are calculated from the blind's actual weight and travel.
Blinds sit in the wettest part of a room. Stainless removes the corrosion risk entirely.
Keep the spring retained until it is mounted on the tube. A loose coiled constant force spring carries stored energy and will unroll unpredictably if released.
Blinds that retract violently at the top of the travel and creep at the bottom
Spring mechanisms corroding in window condensation
Dimensional and load figures are set per order against your drawing or sample, so they are marked TBC rather than filled with catalogue numbers.
| Product Type | Flat Springs |
|---|---|
| Raw Material Options | Stainless steel, Spring steel, Carbon steel, 65Mn, Music wire |
| Wire Diameter Range | 0.1-8 mm |
| Surface Treatment Options | Zinc plating, Nickel plating, Silver plating, Gold plating, Tin plating, Galvanizing in various colours, Dacromet, Black oxide, Phosphating |
| Standard | ISO, non-standard and OEM drawings |
| Processing Route | Material sourcing → Coiling and forming → Heat treatment → Surface treatment → Quality inspection → Packing → Shipping |
| Inspection Equipment | Grinding and shot peening machinery; Precision tensile strength testers; Magnetic powder flaw detectors |
| Packing | Plastic bags, cartons or pallets, or packing to your own specification |
| Payment Terms | L/C, T/T, D/A, D/P, Western Union, 30% deposit before production, 70% balance before shipment |
| Lead Time | 7-15 days after the order is confirmed |
| Minimum Order Quantity | Quoted per part — tell us your requirement (TBC) |
| Dimensions and Load Rating | Made to your drawing or sample (TBC per part) |
Every batch follows the same seven step route, with tensile testing and magnetic powder flaw detection carried out before packing.
Available in Stainless steel, Spring steel, Carbon steel, 65Mn, Music wire, in wire from 0.1-8 mm, with any of our nine surface finishing routes. Geometry, end treatment and finish are all specified per order.
ISO 9001, SGS certificate and RoHS report (stated on the legacy site, certificates pending re-confirmation). Certificate copies are sent on request once re-confirmed.
Against a torsion spring blind mechanism, a flat constant force spring gives far more even operation across the drop, at a higher component cost.
Fabric weight, the full drop, the tube diameter and how the spring is mounted.
Within a band, yes. Tell us the range you want to cover and we will say where it has to be split.
301 is typical for constant force springs because it work hardens to a high spring temper.
Send your drawing, dimensions or a sample. We will confirm the specification and come back with a price and a lead time.
