Reverse double four bar lift

Hi all,

Can anyone done a reverse double four bar lift using 2 linear electric actuator ?

If so can I have a photo of location to read up some more…


Why is this “VEXCode V5 Tech Support?”

Anyways though I do not believe linear electric actuators exist in VEX. There’s linear air powered pneumatics or electric motors that provide rotational motion.

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if you’re looking to build a dr4b from vex components, this is an excellent guide:


Why would you use linear actuators to make a DR4B? the whole point of it (in the context of vex) is to lift upwards. you don’t need a DR4B for this if you are using something that already allows for linear translation lol

Maybe it is not in the context of VRC?
But maybe he is just trying to use vex parts to do a dr4b ?

Anyway @Gerard - you might want to consider using lots of pneumatic actuators for it.

Long time ago, 599D did it… using pneumatic actuation instead of the usual motors.

Edit: 599D did it for a 6-bar lift. But i would imagine you can do the same approach for dr4b as well


This video shows a DR4B (at about 0:25) that’s actuated by both motors and pneumatics, kind of an interesting idea:

Probably doesn’t make sense in VRC nowadays though, since using pneumatics reduces the number of motors you can use – that wasn’t the case back in Skyrise.


Hi All, thanks for the help and the pneumatic actuators are cool…

Im currently making an 8 meter DR4B communication mast arrangement. and need it to be electric actuated with a minimum of two actuators at the joints., any help is greatly appreciated…

Thanks heaps. Gerard

What sort of motion profile are you looking for? is it meant to go straight up? what other design constraints (budget, tools available, etc) do you have

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Hi Ethan straight up.

This is the motion, is you can help that would be awesome.

what is the weight of the object you are lifting and how accurate does it need to be?

If you need high precision I would consider using electric servos for this project. you can buy some from mcmaster-carr (McMaster-Carr ) or hobby king (i still have no idea what the budget or loading conditions are for this) and make a simple parallel 4 bar with a short gear train to get the torque you need

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