- #1

pete

- 72

- 5

https://www.ondrives.com/sr119

They come in many sizes but to take this one as an example it's listed as 6.18N (63kg) at the top of the page. At a glance considering the size of the spring, this seems like a very small number in N and a very large one in Kg.

My maths is not too good so I spent some time looking up how to get this from the specifications and this is my attempt.

This is the bit I’m hoping someone can look at and tell me if I’m doing this right. I took the diameter of the Torque output drum-D3 and divided it to get R - 87mm so 8.7cm. Changed it to meters so .087m then divided by the Torque 6.18 to get 71 N force.

So a barrel with a cable wound around it of the same diameter as D3 will give me roughly 7Kg counterbalance over the specified range of the spring (Dimension L) 12.8 meters.

This still seems low but then I have calculated for a barrel of 17cm diameter. Once you get down to an output shaft of around 15-20mm diameter it would be around the 63kg point.

How did I do?