Linear Actuators?

[riposte_18]

Ahoy all,

For those that don't know, Linear Actuators are generally electro-mechanical devices that will either push or pull an inbuilt rod a certain distance. Larger versions are generally used in Hospital beds in order to prop up patients, for example.

I'm looking to integrate some linear actuators into my machine, in order to solve some logistical problems I've been trying to solve. I've done a search, and seen that other people have had the same idea as me in using Linear Actuators in order to automate certain activities in their Arcade Machine. But unfortunately, I haven't seen any completed examples, only hypotheticals ...

In context, my machine is a coffee table arcade machine, with a monitor built into the surface that can be angled up vertically, and a control panel that will flip out of the side, and hence I'm looking at linear actuators to help support these moving parts. Doing it manually poses some issues around  controlling the degree of rotation and stablity (ie, Control Panel needs to be locked into place when I'm hammering it doing a super on Xmen vs SF). Linear actuators would automate the monitor flipping up and control panel coming out when I turn on the machine, adding a significant awesome factor, but my main drive is to have a mechanism strong enough support the Control Panel during play. I'm trying to avoid as many manual activities as possible, and so automated actuators look might impressive behind the scenes.

Extensions will need to cover approximately 15cm for the CP, and 30cm for the monitor, so most basic smaller solenoids are out of the question.


My questions are threefold
- Anybody used them with any success previously? I've searched through threads, but couldn't find any completed machines with linear actuators that automated manual tasks. I've seen people say they brought some, but threads just kind of drop off from there ...
- Does anybody have any recommendations? Specifically, I'd need one some sort of control mechanism over how far the rod extends, since I'd need it to go specific distances. Anybody got anything to say about how they hook them up?
- Anybody got any idea where to find relatively cheaper ones? I called up linak today, cos they have a subsidary in Australia, and they were asking about 200 for a tiny one (ie, 2 inch stroke length), and medium sized ones for 300-500 bucks! that's nearly as much as I've spent on my machine since its inception! Ebay doesn't seem that much cheaper, unfortunately.

I have some pneumatic struts that I was considering for my monitor, but they require a manual start to get them going, and they will fully extend where possible ... warped some hinges I was testing them against, that's how strongly they extert force, so was hoping to use them as a last resort.

I've nearly completed the frame work of my machine, and the individual control panel and monitor bezel, and just need to finalize this before I assemble it.

Anybody have any experience they could drop in with?

[BobA]

Don't know what they are using but it is the only one that I have seen working.

Project Morph

[huygens]

Saw some really big ones at a surplus store:
http://www.apexelectronic.com/actuator.htm

Probably a bit much though as they have a 16.5 inch throw

[EightBySix]

don't loose faith with eBay yet They come up sometimes used and recycled from things like, as you say, hospital beds. I picked one up for around £40 for my project, which is probably one of those stalled threads you were  referring to. I'm still looking actually as the one I bought was way too powerful (can lift 600 kg!) and a bit too slow. A quicker and less powerful one would be nice, and they seem to go hand in hand. some have limiting switches built in, but they tend not to come up so often for auction, I guess the controllers get left with bed, chair, etc. I suspect some electronics will be needed such as sensors to control them.

[DaOld Man]

A motorized actuator's stroke distance could be fairly easily controlled with a limit switch.

[riposte_18]

Hey all,

Thanks for your feedback. I think buying a linear actuator might become my backup plan, since I found a website (http://www.xrobots.co.uk/linearactuator.htm) which shows how to make a fairly low cost actuator of your own. I already have some of the parts lying around, and looks fairly straightforward to engineer.

Just picked up a 9v dc motor which I plan to run off the pc power supply, which should *hopefully* provide enough torque to turn the driving thread, and grabbed a couple of microswitches that I plan to use to limit the extension and retraction stroke.

Most of the woodworking for my machine is done, and only requires assembly and painting and wiring (boring bits for me:P), so attempting to create the linear actuator might let me keep fiddling with my tools.

EightBySix Ebay does seem to come up with decent stuff, but as an Aussie, shipping gets a bit pricy when stuff has to travel halfway around the world to me