Spring Design û Change in Diameter with Compression 5

[Jalipa]

Hi Guys,

A handbook I’ve got states that a spring has a 3-4% change in diameter when compressed.

I want to fit this spring in a fairly tight hole.

Does anyone know how the change in diameter is calculated?

I seem to recall that there was nifty little formula but I cannot find it.

Can any one help?

Thank you,

J

 

[israelkk]

Jalipa!

The best way to go with a constant force spring is with a Bellevile spring. When the spring height divided by the thickness of the material is 1.41 than you have a region of constant force. More data such as:

1. Inside diameter of spring
2. Outside diameter of spring
3. The spring displacement during work (where you want the constant force
4. The force of the spring

is needed.

With this type of spring the variations in the outside diameter might be smaller.

In the past I have designed and built Bellevile Snap (Bi- stable) springs which have two stable positioned. Some were for 2 to 10 kg force and some were for 250 kg force.

I can check if a constant force spring can be done if you can provide the info.

israelkk2001@yahoo.com

http://www.webspawner.com/users/israelkk/