Torsion Spring Coilers

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Torsion Spring Coilers

 

 

Our CNC Torsion spring machines are precise and durable with high speed which makes them so popular among our customers. Wide wire range from 0.15 to 4.00 mm, easy to set up, Optical sensors, powerful computer program and complete set of tooling, makes this machine able to produce any demanded shape of torsion spring with high speed.

 

All About Torsion Springs

 

Perhaps the easiest example of a torsion spring in action is a clothespin. As you can see in the image at the bottom, the spring holding the two wooden clamps together is a torsion spring. The spring allows clothespins to clamp tightly on drying socks, chip bags or whatever other applications you might find for them.

You’ll also find torsion springs in ATV suspension systems, clipboards, hinges and ratchet tools–and the list doesn’t end there. Torsion springs work in a different way than compression and extension springs, but they’re still one of the world’s most common springs.

How Torsion Springs Work

Torsion springs are closed loop, so that each coil touches the next. Their ends are configured in different ways. Like extension springs, torsion springs must attach to other parts at both ends in order to work. When forces act on the spring ends, they tighten the coils of the torsion spring. As the spring returns to its resting coil diameter, it brings the attached parts with it.

To hold them in place, torsion springs are often placed on a mandrel, a small rod or peg, that fits inside the coils. The fixture must be snug enough to avoid excessive play, but loose enough to allow full motion. Alternatively, the entire spring can be placed in a blind hole to keep it in place. In other cases, as in the clothespin example, the spring ends are configured in such a way that they connect the spring securely to its adjacent parts.

Depending on the application, torsion springs can be left hand, right hand or double. The latter configuration is like two springs (left and and right hand) coiled from the same wire. 

Manufacturing Torsion Springs

 As with any spring, a variety of parameters must be taken into account in order to properly calibrate a spring coiling machine to produce torsion springs. In addition to general size and shape, designers of torsion springs must take the following into account:

•             Spring rate: a measure of the force necessary to act on the spring

•             Maximum deflection: the farthest a spring can be pushed before damage occurs

•             Pitch: while most torsion springs are close wound, some are wound with pitch to reduce friction

•             Ends: the wire forms at the ends of the coil that attach to external parts

CNC spring coiling machines are usually able to produce torsion springs. In order to produce finished springs, coiling machines must be able to handle a variety of end configurations. The plain ends of a compression spring, for example, would not allow torsion springs to function.

The American standard for spring coiling is to use a single-point coiling system. Single-point coilers are more versatile in terms of the work they can perform. Altinkuralmetal offers a range of CNC spring coilers that are capable of producing torsion springs to nearly any specification.

 

 

2.5.2- Torsion Spring Calculations

Torsion Spring Calculations

Definition of Torsion Spring Calculations:

The process of calculating several torsion springs dimensions such as the computing of shear modulus of a spring wire, Youngs modulus of spring wire, Poisson’s ratio for spring wire along with a springs wire diameter, outer diameter and number of active coils to obtain a torsion spring calculation.

Here is an easier and faster way to calculate your torsion spring calculations by using a free online spring calculator; which provides you with a full spring analysis of your spring. Just enter a few of your torsion spring's dimensions, and you'll have all the information you need to make sure your spring will function correctly in your application.

Get Spring Creator App for Android Devices

 

 

Basic Torsion Spring Calculation Formulas:

Sometimes, you might only have a couple of your torsion spring's dimensions but in order to calculate other things such as rate and travel, you'll need to know a bit more. Here you will see a couple examples of different scenarios where a certain spring dimension is needed.


To Calculate Wire Diameter:

If you only have your Outer Diameter (OD) and Inner Diameter (ID) but need Wire Diameter (WD), you must subtract your Inner Diameter (ID) from your Outer Diameter (OD) and then divide the result by two as shown in the formula below:

(Outer Diameter – Inner Diameter) ÷ 2 = Wire Diameter
(OD - ID) ÷ 2 = WD

 

 

 

To Calculate Outer Diameter from Inner Diameter:

Multiply your Wire Diameter by two and then add it to your Inner Diameter; as shown in the formula below.

2 * Wire Diameter + Inner Diameter = Outer Diameter
2WD + ID = OD

 

 

 

To Calculate Inner Diameter from Outer Diameter:

Multiply your wire diameter by two and then subtract the result from your Outer Diameter; as shown in the following formula.

Outer Diameter – 2 * Wire Diameter = Inner Diameter
OD – 2WD = ID

 

 

To Calculate Mean Diameter:

The mean diameter is calculated by taking one wire diameter and subtracting it from your torsion spring's outer diameter or adding it to the inner diameter as shown below.

Outer Diameter – Wire Diameter = Mean Diameter
OD – WD = MD Inner Diameter + Wire Diameter = Mean Diameter
ID + WD = MD

 

 

 

 

To Calculate Your Spring's Index:

This spring calculation is needed to make sure that the torsion spring you require is manufacturable. To calculate index, you must divide your mean diameter by your wire diameter as displayed in the following spring index formula.

Mean Diameter ÷ Wire Diameter = Index
MD ÷ WD = I

 

 

 


 

Advanced Torsion Spring Calculations

You'll need a spring rate that will work with the loads you plan to apply to your torsion spring as well as the degrees you plan to travel. Below you will find the torsion spring calculation for rate as well as load.

Formula to Calculate Torsion Spring Rate:

Rate Per 360 Degrees
(R) = Ed^4 / 10.8 DN

Explanation of Symbols:

  • d = wire size (inches)
  • D = Mean Diameter (inches)
  • N = Number of active coils
  • R = Rate per 360 degrees
  • S = Stress (lbs / square in)
  • P = Load (lbs)
  • M = Moment (inch-lbs)
  • D / d = Index correction
  • E = Modulus of Elasticity
Modulus of Elasticity "E" for common spring wires.
  • PSI x 10^6
  • Music Wire = 30 psi
  • Stainless Steel = 28 psi
  • Chrome Vanadium = 30 psi
  • Chrome Silicon = 30 psi
  • Phosphor Bronze = 15 psi

 

Formula To Calculate Torsion Spring Load / Force:

Multiply your spring's rate per degree by the distance traveled in degrees as shown in the following formula. Load = Rate Per Degree * Distanced Traveled
L = RpD * DT

How to Calculate Your Torsion Spring's Rate From Load and Travel:

Divide the load by the degrees of travel to calculate the rate of your torsion spring as displayed on the formula below.

Load ÷ Distance Traveled (in degrees) = Rate
L ÷ DT = R