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JJ21
Oct21-09, 10:53 AM
Hi,

I need to get a precise linear oscillatory motion from a rotary input? Its for a compact carving tool. Any ideas on how to control the displacement? Thnks

Integral
Oct21-09, 12:51 PM
Hi,

I need to get a precise linear oscillatory motion from a rotary input? Its for a compact carving tool. Any ideas on how to control the displacement? Thnks

Strictly speaking the bolded words are mutually exclusive. You simply cannot have linear oscillatory motion. You need to place some constraints on your needs. For example over what range do you need approximately linear motion.

JJ21
Oct21-09, 12:57 PM
Sorry, by linear oscillatory motion i meant reciprocating motion. It would be over several fixed ranges from 1mm to 3mm for example.

minger
Oct21-09, 12:59 PM
Something like this:
http://en.wikipedia.org/wiki/Multibody_system#Example

FredGarvin
Oct21-09, 01:03 PM
Something like this:
http://en.wikipedia.org/wiki/Multibody_system#Example
That was the first thing I thought of. You can have multiple holes to adjust the linear travel distance.

Mech_Engineer
Oct21-09, 01:09 PM
It would also be possible to use some form of a camshaft which has varibly sized lobes for adjutsing the travel. This would also make it possible to have the motor located parallel to the reciprocacting point, rather than perpandicular to it.

JJ21
Oct24-09, 10:43 AM
Thanks for the ideas! I've been researching how to vary the stroke length of a slider-crank mechanism and have found a few methods but no "practical" solution of how the slider-crank could be adjusted in real life for example the slider-crank mechanism attached below.

Any ideas?

Thanks

minger
Oct26-09, 08:02 AM
As Fred mentioned, you can have various holes drilled on the crank (i.e. the radius of the rotating arm). That will change the stroke.

If you need this updated in real-time, then a more complex solution might be needed.