Telescopic Linear Actuator Experts

Jacques de la Croix · Post by **Jacques de la Croix** » Mon Apr 12, 2010 2:04 pm

I'm putting together an art piece that requires an electrical lift that can
extend more than double it's retracted length. I'm having difficulty locating
a telescopic jackscrew that would do the job. Google has not been my friend.
Hoping some astute burner gearhead in the aviation industry knows where
I can get my hands on a few of these. More details can be discussed later
if someone has knows what I'm talking about.

Peace,
Jacques

Snow · Post by **Snow** » Mon Apr 12, 2010 2:11 pm

that is easier to accomplish hydraulically, than electrically. Have you considered hydraulics or even pnumatics? I'm not sure what kind of capacity you're talking about.

Dork · Post by **Dork** » Mon Apr 12, 2010 2:15 pm

I did some tinkering with electrical actuators back in my robot days and don't think I've ever seen a telescoping actuator like you describe. Hydraulic or pneumatic I can understand but I'm not sure how it would work with electric.

I would think there would be a way to accomplish what you need with a different mechanism of some sort. There should be a way to translate the small stroke of the actuator into a larger movement of the art piece. Maybe you could describe what you're doing in greater detail?

dragonfly Jafe · Post by **dragonfly Jafe** » Mon Apr 12, 2010 3:25 pm

how about looking at construction lifts? I have seen some 1-man lifts with several nested metal slides, that get lifted by a chain and electric motor. These have multiple sections - might be want you are looking for.

Good Luck!

Jacques de la Croix · Post by **Jacques de la Croix** » Mon Apr 12, 2010 3:26 pm

Thanks Snow & Dork for your replies!

Here's the basic idea:
http://i43.tinypic.com/2nlbi2q.jpg

I'm looking at reduction/servo drive to power the screw:
http://www.nookindustries.com/jack/JackHome.cfm

I haven't been able to find the screw off-the-shelf, but I have seen them
while cycling through the UAL maintenance plant @ SFO.
Also haven't had much luck finding commercial airplane salvage yards in
SoCal. But I've been told about one in Mojave. Again, Google has not been
my friend. May have to take a drive out there.

Anyway if these links happen to jog your brain as to a source for a screw
such as this, I'd GREATLY appreciate your feedback!

Jacques

Jacques de la Croix · Post by **Jacques de la Croix** » Mon Apr 12, 2010 3:28 pm

I guess I should also add that I'm only looking at a retracted length of 15"
and extending to 32".

Also, max weight is 100lbs.

motskyroonmatick · Post by **motskyroonmatick** » Mon Apr 12, 2010 5:57 pm

Looks like you need a small multiple stage hydraulic cylinder. Ive only seen them large and on dump trucks or 4 story elevators.

You could do the cable and sleeve method with a winch. I just can't find the words to describe it right now. Sort of like a retractable antenna.

Jacques de la Croix · Post by **Jacques de la Croix** » Tue Apr 13, 2010 12:33 pm

"You could do the cable and sleeve method with a winch. I just can't find the words to describe it right now. Sort of like a retractable antenna."

Anything that could leak, I'm ruling out.

The cable/sleeve/winch idea is interesting.
I have an idea how that could work.
Basically a top internally mounted pulley that pulls/links to 2 or 3 sleeved tubes.
I'll have to take this to the drawing board.

BTW, you're going to have a TIG welder on the playa?
Nice!

motskyroonmatick · Post by **motskyroonmatick** » Tue Apr 13, 2010 5:37 pm

Jacques de la Croix wrote: BTW, you're going to have a TIG welder on the playa?
Nice!

It is a small one but handles nearly all the welding projects that come my way. It converts to stick welding for the larger stuff.

gyre · Post by **gyre** » Tue Apr 13, 2010 7:20 pm

Scissor jack with a stepper motor?

I think the screw you're talking about is an acme thread?

Post by **mdmf007** » Tue Apr 13, 2010 11:43 pm

gyre wrote:Scissor jack with a stepper motor?

I think the screw you're talking about is an acme thread?

The only way this is getting done is with three stages. The physics are not possible for a cylinder to extend longer than the first stage. You cant even double it with hydraulics because you need some retention for the cylinder.

If you go with hydraulics or pneumatics, remember that cylinders are not side load rated in most cases. They are linear, they push and they pull. From what I have seen you would be best off making a scissor lift, cheap and easy to do. then you could turn a small single stage cylinder loose on it and extend it a long ways.

Ugly Dougly · Post by **Ugly Dougly** » Wed Apr 14, 2010 9:18 am

Jacques de la Croix wrote:Anything that could leak, I'm ruling out.

You're driving something out there, Jack?

Dork · Post by **Dork** » Wed Apr 14, 2010 9:55 pm

Scissor lift for sure. Much more stable and easier to source parts.