Thread: Good with math?

circumference is twice the radius times pi.

2 pi r.

Which is about 25.46mm

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Edit:

Whilst the above is true,
if you need 40mm stroke length on both cables, then:
when the pivoting arm upright, one cable is at 40, the other 0;
and when it's turned 90 degrees, then the first cable needs to be at 0, the second at 40.
Remember that the cables won't follow the nice arc of a circle by themselves, so the measurement you want is the stroke length, 40mm!

Originally Posted by thethink

circumference is twice the radius times pi.

2 pi r.

Which is about 25.46mm

Thanks, couldn't remember the formula Been a 8 years since I needed it

oops, 'second thoughts' (above)

Got through then realised that the cable isn't going to follow round a circle - well, not without a design modification it isn't.

But just be aware that the above design gives a sinusoidal response to the linear action, which should be ok for what you're doing.

Originally Posted by thethink

oops, 'second thoughts' (above)

Got through then realised that the cable isn't going to follow round a circle - well, not without a design modification it isn't.

But just be aware that the above design gives a sinusoidal response to the linear action, which should be ok for what you're doing.

Yep, fully aware, it'll actually work out better than my crappy picta

Thanks

...................and it's MATHS - shortform of mathematics

Unless of course you are an American

If I understand correctly

You want this to pull the left cable 20mm, to rotate the lever 45* anti clockwise (from the neutral position as sketched). And pull the right cable 20mm to rotate the lever 45* clockwise. Total 40mm travel and 90* rotation.

If this is the case.

Your lever length is 20mm / sin 45* ~ 20mm / 0.707 ~ 28.3mm

Originally Posted by Bush65

If I understand correctly

You want this to pull the left cable 20mm, to rotate the lever 45* anti clockwise (from the neutral position as sketched). And pull the right cable 20mm to rotate the lever 45* clockwise. Total 40mm travel and 90* rotation.

If this is the case.

Your lever length is 20mm / sin 45* ~ 20mm / 0.707 ~ 28.3mm

90 degrees, one cable pull, one to push(well get dragged), the actuator lever will actually be on a 45 to the right and pull through to 45 on the left.....Now I think about it

But its the same thing as you thought

Originally Posted by ladas

...................and it's MATHS - shortform of mathematics

Unless of course you are an American

Thanks, a highly important part to actually getting out in the shed AND doing some work, sorry to have missed it