Hi, I want to create a scissor lift mechanism to raise and lower a box for a desk I'm making. The L & W of the box is 15.5". The height difference that needs to be achieved (from fully collapsed (with acceptable angles) to fully extended) needs to be 15.5". I basically need it to go from completely flush with the desk to fully risen. I've looked around a lot to find the formulas that would be needed for this but all I've found is functions for the max load/force required to lift that load. I basically need to know the lengths the arms need to be and at what angles. I would like to try and keep the stroke length required to be, at or under 4". The linear actuator will at the bottom of the lift as opposed to the middle. If anyone could find the measurements for me or give me any more explanation that would be greatly appreciated.

-Alex katz

 

Hello Alex,
I did this many years ago, and the easiest way to do it is to apply your loads at different angles of the scissor members starting from rest to max height, that is a static analysis at these angles so you might have to make some logical and robust assumptions. If you can, build a prototype and test it to verify your design calculations (it was built right) - depending on how you test it you might also be able to validate your design purpose (built the right thing) - if it passes the test(s) then you have your production rum model.
Good luck
John N.