wind up timer device

hi all

can someone help me find out a way to make a wind up timer? - all it needs to do is manually wind up by hand, unwind through a series of gears slowly.....but needs to have a strength of about 2kg/cm torque. something to unwind for about 30 minutes would be perfect

is there anything out there which can be used..or a simple way to make using spur gears and a coil spring?

many thanks

lemonie8 years ago
2Kg per cm?! Have you thought about gravity and weights?

oem_odm (author)  lemonie8 years ago
Hi Lemonie,

Not sure why you keep mentioning that.

Gracvity _ weight would provide a 1 time action - I need a repeated rotation action which provides said output torque.

I could use a motor but prefer to use a wind up timer meachanism as doesn't use batteries....

lemonie oem_odm8 years ago
The wind up mechanism is also a 1 time action: you'd have to wind both up. I find the torque to be quite high, for that much force I was thinking clock-weights might be a good option. E.g. 100Kg on a cable on a 20cm diameter drum would give you 10Kg per cm, which you could gear to the 2 you need?
Circumference of the drum would be 63cm, 5 wraps gives 5 revolutions for ~3 m of cable (~10 feet). Gearing this down you'd get 25 revolutions output?
You'd need a big spring otherwise wouldn't you?


oem_odm (author) 8 years ago
hi lemonie - 2kg/cm is motor torque measurement. i would need the output of a wind up timer module to produce similar torque... :-)