upside down cam with spring

[david181]

Hi, im creating a mechanism that needs to be able to lift a plank of wood up and down arpund a pivot. However, there isn't enough space below the wood to enable me to place a cam. So i thought I might be able to place a cam above the wood - although this would mean the follower would have no gravity to keep in contact with the cam, if I placed a spring under the wood it should spring back up meaning it is always in contact with the cam.

I'd like to know if this idea is any good and if its been used before, or if there are any mechanisms that would make much more sense in this case.

 

[desertfox]

Hello david181

Overhead cams in car engines have a spring on engine valve stems (followers)to keep them in contact with the cam.
You haven't given enough information regarding your device
for anyone really to help you further. Could you provide
more info like sizes,materials,spped,masses,more application
info etc.

regards

desertfox

 

[Cheddarcaveman]

The mind boggles! What exactly is this device going to do? Is it a new type of see-saw?
If it is so near to the ground that you cannot get a cam in there, then your overall movement is going to be very restricted!

 

[zekeman]

Unless you need a specific periodic motion, you are better off using a quadric mechanism that can be easily implemented and if you are not familiar can be viewed in any book on mechanisms.

 

[JStephen]

Note that on any cam-type assembly that requires parts to accelerate faster than gravity, some type of spring will be required even if upright.