Calling all you engineers...

[Itsallicanafford]

I was wondering if I could have some advice. I am designing a new range of height adjusting tables, which roughly speaking are a 1500x750mm top powered by 4 no. Electronic actuators, one in each corner. The specification calls for a total even loading on 350kg on the table. Each actuators are rated at 1200n force, weight of top frame and various accessories could be as much as 100kg.

My question is, with an evenly spaced load, is it as simple as saying 4 no. Actuators with a total combined loading rating of 4800n therefore the total loading of max 450kg is ok or is there any drop off with the actuators combined total loading.

Many thanks in advance for any advice.

[V8LM]

IF the mass was evenly distributed then yes, the force in each actuator is equal and 1/4 of the total.

[anonymous-user]

Check your actuators for their "holding" rating. ie when un-powered! Some types of linear actuator can not "Hold" the same force they can apply unless you keep them powered (stalled) which generally you don't want to do

[Itsallicanafford]

Thanks for the responses, much appreciated. We are using Linak actuators and they assure me that they fix their position when unpowered or defective and our prototype bench is performing well. Good to hear about the weight loading. just wanted to check that I was not missing something obvious.

Thanks again

[annodomini2]

If you want it to move with load you need to account for extra force purely for the acceleration plus friction.

[annodomini2]

If you want it to move with load you need to account for extra force purely for the acceleration plus friction.

[Otispunkmeyer]

Sounds complicated... How do you keep the table from raising or lowering unevenly? Im not sure you can assume that each actuator will move at the same pace. You'd need some level information and a feedback loop to keep it flat.

Is there are reason you cant use just one actuator and gear system? ( I realise it could be heavy this table, but surely worth a few fag packet calcs?)

[Fishtigua]

You could use hatch lifters, used on motorcruisers to open the engine hatch. I've fitted them as pairs but never as a 4.

http://www.aquafax.co.uk/html/products.asp?ID=303

[Marty63]

Motorcycle lift me thinks ??