raise and lower flatscreens(or other stuff)

[endover]

I'm between projects at work right now and had a little time to bounce around on the web yesterday. I came across a guy that has his 53 inch flat screen on some type of stepper motor or linear slide mechanism that miraculously makes it pop up into view and lower down (completely protected) and out of view.

Without opening up a bag of worms on a plethora of recommended products you can buy from some high dollar specialty store..... Does anyone have any cool and farily inexpesive ideas that they've done to this effect(that's not cheesy!...vibrates....rattles.....tips over.....etc....).

I'm a mechanical engineer and think that kind of stuff is pretty cool if it can done without spending a jillion bucks! I don't even have a flat screen TV but who's got some creative ideas out there that they built from stuff they found at Radio Shack(or wherever)?

[ironwoods]

A linear actuator?

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=329-300

[michaelstano]

http://www.televisionlifts.com/pages/813387/index.htm

Not exactly cheap, but perhaps you can get some ideas.

[Tom Adams]

A guy who did a custom built-in A/V wall unit for me several years back showed me a motorized TV lift cabinet that he built from scratch for a client. At the heart of the lift system was a scissor type automobile jack (it was small and light weight. Probably from a foreign car or summat) and an electric motor that drove the jack via reduction gears. He used heavy duty draw slides and a couple of micro switches for travel limit. The cabinet didn't have the decorative sides on it so you could see it in action. He had a 250lb weight on the shelf and the unit worked flawlessly and was very smooth. He never said how much he charged for it though.

Tom

[endover]

Aha! That's the kind of ingenuitive crap I'm talkin about! That's some good stuff there! hmmmm.....I'll have to go think that one over!

[dkp]

How about a projector with a motorized screen?

[thebes]

How this for simple. Should work.

Two channel rails with small wheels like you see on mechanical conveyor belts, two sprockets from a junked motorcycle, one motorcycle chain and a hand crank. Actually you might need four channels with cross=bracing for stability.

Instead of the hand crank you could drive it with a slow revolving electric motor. You could go belt driven but with the weight of some of these tv's you'd have no problems with slippage using the motorcycle gears.

[Tom Adams]

Not to knock your idea thebes, but you'd be hard pressed to get an electric motor to turn that slow. I guess you could play around with sprocket sizes though. The other trick would be getting both sides of the TV shelf to raise/lower at the exact same rate. If they don't, then you'll get some binding on the slides/tracks/whatever.

Tom

[Tom Adams]

This will obviously tell you I have too much time on my hands today.

A fancy system would be a linear servo motor with electronic feedback such that you could program the motor to slow down towards the end of it's lift.

Another method would be 3 or 4 small hydraulic jacks whose hydraulics are tied together via manifold. The hydraulic pressure would come from a small pump. Lowering would involve a solenoid operated check valve.

Or how about a counterweight system? Whereby you have a counterweight that is equal to the TV & shelf weight. A slight pull on the top of the cabinet brings the TV up.

I'd also suggest a variation on the ejection seat, but that one is gonna take a bit more tweaking before I give out any details. And before I can tweak the design, I've got a few (ahem) holes in the ceiling to repair.

Tom

[Champagne taste beer budget]

I've been trying to think of ana/c motor that would have the slow speed and high torque required, but to no avail. If you wanted to get a 110 to 12/13 volt convertor with sufficient amperage, an electric window motor from a car would probably work. You can lean on them pretty hard when going up and not stop the window from raising. I love coming up with cheap alternatives to expensive stuff using automotive parts, a little ingenuity goes a long way sometimes, and can end up looking just as good, if not better, than the store bought items. (Of course, sometimes they look like crap but work wonderfully, but who cares if it's in a fish-house or out in the garage.)

Tom, I like the hydraulic jack idea, but I think travel could end up being an issue. You could, however, make a lever/fulcrum setup where 1 inch of travel at the jack post equals 4,6,8 or whatever at the other end of the lever.

[thebes]

You're right Tom I didn't think it through. But how about a couple of those, not sure if this is right, worm gears. You know steel tubes with the big thread like things machined into them. Add you stops like an elevator and you're on your way.

Now that I think of it, ask the elevator repair guy in the bulding you work in, I bet you he'd come up with something really simple that would do the job.

[michael hurd]

You don't necessarily need a low speed ac motor to do the work, a 1728 rpm motor will work fine, provided you give it ample reduction. At the place where I worked years ago, we had a 3hp motor coupled to a 4 speed truck transmission, with an additional planetary reduction unit in a home-built freight elevator. It worked fine, as long as you didn't overload it (400 lbs max), or you tried running the tranny in 2nd gear.

A linear actuator would also do the job, and they are quiet. A power window motor will work wonders, especially if you have two in tandem, one for each side. The only additional cost would be for a 12 volt power supply or a battery charger.

[michael hurd]

Beer budget: the type of jack he was referring to is a mechanical scissor type jack with a screw that you turn to raise the vehicle. The girlfriend has one in her honda that is factory, and will lift about 10" from it's flat 2 1/2" height.

[Champagne taste beer budget]

I guessed that was the type. In act, my wife had one in her Honda that she owned when we met. The jack got taken out for one reason or another and floated around the garage till a couple months ago, I wanted to keep it for some unknown future project, but unfortunatly it, and a lot of other great "JUNK", as my lovely wife referred to it, got taken to the dump when we took down the old house.

[michael hurd]

A trip to a self-serve wrecking yard should yield all sorts of goodies. We have one here, where I tend to overload my toolbox every trip out. You never know when you need blade type fuses, metric and standard body bolts with speed clips, trim fasteners, plastic fasteners, and wiring pigtails.