Extension springs
Shuangyuan can produce various sizes and shapes of tension spring with different shapes of hooks, such as long loop, German hook, British hook and side hook.
Tension spring aslo called extension spring.
With wire diameter range from 0.15-60mm.
All the tension spring are manufactured by fully automatic spring making machines.
These tension spring are widely used in computer, electron, home appliances, camera, instrument, motorcycle, automobile and other industry.
Main material: Carbon spring steel, alloy spring steel,
Refractory steel, stainless steel, high temperature
Resisting alloy, corrosion-resistant alloy and bronze etc.
Pls provide us the drawing or sample,we can make as per your request.
Description of parameters for extension springs
Physical parameters of extension springs
d (wire diameter): This parameter describes the diameter of wire used as material for spring.
De (external diameter): External diameter of a spring concerns both hooks and coils. Tolerance for this parameter is (+-)2%(indicative).
H (Hole): This is minimum diameter of hole in which spring can work. Tolerance for this parameter is (+-)2%(indicative).
Ln (Maximum length): Maximum acceptable extension length for a spring. It is also the maximum extension for static applications. Tolerance for this parameter is (+-)15%(indicative).
Fn (Maximal force): Maximal acceptable force which can operate on a spring. It is also the maximum force for static applications. Tolerance for this parameter is (+-)15%(indicative).
L0 (free length): Free length is measured in spring's free state. Tolerance for this parameter is (+-)2%(indicative).
Nr of coils: This is a total number of coils in a spring - in the picture above it is equal to six.
R (Spring rate): This parameter determines spring's resistance, while it is working. It is measured in 1 DaN/mm = 10 N/mm. Tolerance for this parameter is (+-)15%(indicative).
L1 & F1 (length under charge F): The charge F1 at length L1 can be calculated using the equation : F1 = Fn - R(Ln-L1). Equation derived from the previous for calculating L1 = Ln - (Fn-F1)/R.
Hooks: Extension springs with german hooks are produced in two versions: with hook positions of 0 degrees and 90 degrees as shown in the picture above.
Materials of Extension spring
A (Music Wire): Steel that conforms to the DIN 172233 class C1 standard.
I (Inox steel): Inox 18/8 mark Z10 CN 18.09.
Tolerances of Extension spring
maximal force: Tolerance for the maximal force is (+-)15%(indicative).
maximal length: Tolerance for the maximal length is (+-)15%(indicative).
Spring rate: Tolerance for the spring rate is (+-)15%(indicative).
>>Tension springs
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