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Constant Torque Spring (Type A) – Precision Flat Spiral Spring
Constant Torque Spring (Type A) – Precision Flat Spiral Spring for Reliable Torque Control
Need Consistent Torque in a Compact Space?
Constant torque springs (Type A) deliver uniform restraining force, smooth operation, and high torque output within a small footprint. Whether you need reliable counterbalancing, smooth retraction, or consistent tension, these springs are the solution.
What is a Constant Torque Spring (Type A)?
A Constant Torque Spring (Type A) is a precision-engineered flat spiral spring made from pre-stressed strip material. It is tightly wound and mounted between two drums. When the spring is unwound from the output drum, it naturally attempts to return to its original curvature on the storage drum. This action generates a consistent torque load when the outer end is attached to another drum.
Key Characteristics | Feature Benefit |
Constant torque output (zero gradient) | Stable, predictable performance |
Low output torque option | Suitable for sensitive mechanisms |
No friction between coils | Smooth operation with low hysteresis loss |
Long service life | Reliable performance for thousands of cycles |
Large rotation angle | Ideal for multi-turn applications |
Service Life & Performance
Maximum torque is achieved at approximately 2,500 cycles
Increasing the output drum diameter extends service life
Long service life – engineered for reliable, long-term operation
Why Choose Constant Torque Springs?
Constant torque springs apply a nearly uniform restraining force against unwinding while delivering high torque within a compact space. These characteristics make them ideal for applications requiring smooth return, recovery, and counterbalancing.
| Typical applications include: | Industry Applications |
Cable & Hose Reels | Automatic retraction systems |
Aerospace | Counterbalancing, deployment mechanisms |
Medical Devices | Surgical instruments, patient positioning |
Windows & Blinds | Cordless window covering systems |
Automotive | Seat belt retractors, pedal mechanisms |
Industrial Equipment | Feeders, conveyors, spring motors |
Engineering & Custom Design Support
At SEME Hardware, we specialize in custom constant torque springs. Our experienced engineering team can help you from the initial design phase through to full production.
We use our own engineering formulas to find the best solution for your specific application requirements.
Key design parameters we consider:
Hole / shaft diameter (ID / OD)
Required torque (load)
Working height / deflection
Material selection
Strip thickness and width
Number of active coils
Operating environment
Custom Spring Design Input & Output
When you send us your requirements, we provide:
Input Parameters
Calculation Results
| Input Parameters | Calculation Results |
Hole / shaft diameter | Spring rate (stiffness) |
Required torque / load | Working load (±10%) |
Working height | Solid height / outer diameter |
Material type | Working curve / performance chart |
Strip thickness & width | Life cycle prediction |
Whether you need a standard constant torque spring or a fully customized solution, send your application requirements to our team. We will personally review your needs and recommend the best solution for your project.
Why Partner with SEME Hardware?
✅ 10+ years of experience in precision spring manufacturing
✅ Full OEM & custom solutions – tailored to your specifications
✅ Free engineering support – we help you find the right design
✅ Fast sample turnaround – prototypes available for testing
✅ Global shipping – to North America, Europe, Asia, and beyond
What Our Customers Say
"SEME Hardware provided excellent engineering support and delivered exactly what we needed. Their constant torque springs perform flawlessly in our medical devices."
— Medical Equipment Manufacturer, Germany
"Fast response, professional service, and great quality. We have been using SEME springs for our cable reels for over 2 years."
— Industrial Cable Reel Supplier, United States
Frequently Asked Questions
1. What is the difference between constant torque spring and constant force spring?
A constant force spring provides linear force for retraction/tension, while a constant torque spring provides rotational torque for counterbalancing and multi-turn applications.
2. What is the typical service life?
Our constant torque springs are engineered for long service life, typically achieving optimal torque at around 2,500 cycles and continuing reliable operation beyond that.
3. Can you customize the torque output?
Yes. We can customize torque output based on your specific application requirements – from low torque for sensitive instruments to high torque for industrial equipment.
4. What materials are available?
Stainless steel (SUS301, SUS304), high carbon steel, and other materials upon request.
5. Do you provide samples before mass production?
Yes. Prototype samples are available for testing and validation.
6. What is the lead time for custom springs?
Samples: 7–10 days. Mass production: 15-20 days depending on quantity.
Contact Us
📧 Email: [email protected]
📞 WhatsApp / WeChat: +86 186 6511 1545
Send us your requirements – we'll reply within 24 hours.
