Constant tension

[mariusov]

I'm constructing a contraption in which I need to simulate a weight-based force without the use of the weight (e.g. with gears and springs etc.). I need to be able to move the wheels in the drawing, but keep the force constant. Any suggestions?

Thanks

 

[BobM3]

How much movement?

 

[mariusov]

The left wheel must be able to move a distant in each horizontal direction equal to half the space between the wheels. The length of the wire is not an issue.

 

[imcjoek]

1) Pneumatic cylinder
2) Reel spring (like in a tape measure)
3) Some kind of electric motor setup

The list goes on. You need to provide more information.

Are you doing a dancer for a winding machine per chance?

 

[SincoTC]

I think what you need is pretty much spelt out in your OP, namely, "contstant force spring". look at this UK site or google that term for a nearer source.

http://www.emmottsprings.co.uk/

 

[mariusov]

SincoTC: You are right, a constant-force spring would cover my needs, except that I can't find one strong enough. I need a spring that can hold at least 2 kN.

 

[mariusov]

I'm building a model of a production oil-pipe by the way.

 

[FeX32]

Pneumatic is the simplest and easiest.

Fe

 

[SincoTC]

I didn't realise it was that heavy! The largest contant force spring I've seen was 2" wide x 1/32" thick and had a load rating of about 40lb, if you have the room, multiple units could be mounted in parallel to get the required rating.

Have you considered Gas Springs, they are simple, self contained and have a fairly flat force curve?