Constant Force Spring

Constant Force Spring is a specially designed spring that delivers near-constant output force during extension or retraction, unlike the variable force characteristics of traditional springs. Below is a comprehensive analysis of constant force springs:

1. Core Principle & Structure

• Unique Design:

Consists of a pre-stressed spiral steel strip (typically high-carbon stainless steel) tightly wound into a coil. When extended, the strip unwinds from the spool and recoils when retracted.

• Constant Force Mechanism:

The change in bending radius cancels out the material’s elasticity, maintaining stable force output throughout (Hooke’s Law does not apply).

3.  Application:
   
   • Office Equipment:
     ✦ Printer paper auto-rewind mechanisms
     ✦ Monitor screen（lift systems)

   ✦ Electric Fan

       Industrial Use:
   ✦ Automatic cable/hose retractors (e.g., CNC machine cable management)
   ✦ Constant-pressure control in safety valves

   • Medical Devices:
     ✦ Electric hospital bed height adjustment
     ✦ Force feedback systems in surgical instruments
   • Automotive Industry:
     ✦ Seatbelt pretensioners
     ✦ Anti-pinch mechanisms for power windows
   • Shuangyuan produce this kind of spring with  thickness 0.2mm~0.4mm, width 10mm~30mm, length according to customer requirements.
   • Various kind of ends for your to choose.

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