Weird Project, need mechanical advice...

[markus shaffer]

Hello all,

I've got a pretty simple project in mind that has a mechanical componant to it that I've no idea how to go about making work. Basically, I want to build a small box, about 1 foot square that will have a mechanical lift of some sort inside. It doesn't need to be anything super strong as it only needs to lift a couple pounds.

The idea of a scissor lift would be great, but on a small scale. However, if there is something better, I am open to any ideas. It will need to lift up about 8-10 inches high. Also this needs to be motorized so that It can be activated from a foot switch of some sort. Basically, the idea of a guitar foot pedal. Step on it once and it goes up and stops. Step on it again and it goes down and stops. Slow and dramatic is the key here. This will be housing a light, so the idea is for it to rise at a pretty slow rate.

Any advice on this would be greatly appreciated.


-Markus

[Hoa Dinh]

2 TON, 12V SCISSOR JACK (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94491)


http://www.harborfreight.com/cpi/photos/94400-94499/94491.gif

[markus shaffer]

Hoa,

Thanks for the reply. I guess I should also have mentioned that this should be lightweight. A 50 pound jack would certainly do the job, but this is going to be something that gets hauled around some. Thus the lighter the better.

-Markus

[Greg Sznajdruk]

Markus:

On occasion I watch Monster Garage ( not much wood working takes place in this show) they on occasion need to open doors or the like. I notice they use what they call electric actuators. They appear to be a 12 volt dc motor with a screw, the screw seems to come in various lengths. Don't know if this would serve for your project. Also have no idea where you could get same.

Greg

[Robert E Lee]

Markus, have you looked at surplus center? They have linear actuators that might do the job. Just put a www and a com
Bob

[Ian Barley]

Markus

Available power sources?? If compressed air is an option then the job would be a cinch for any suitable pnuematic actuator with a 5/2 foot pedal switch as the control? Cost can be kept low as well as weight.

[markus shaffer]

Thank you guys for the ideas.

The linear actuator idea I think will work. Surplus center seems to have something along the lines that I will be able to rig up. I'll have to research it more.

Ian, power will be electric. Ideally AC power as I want to plug this in and have it work. I might run an in-line transformer inside the box if necessary. The more simple I can keep this, the better.

Any other ideas would still be appreciated.


-Markus

[Doug Shepard]

An electronic trailer leveling jack, or at least the innards might be worth checking out. These usually go under RV's and work as a system to auto-level the unit once parked. I don't have a clue how much these cost though, but you might be able to find a used one on eBay.
Do I sense a 60's Austin Powers swinger pad in the works? Maybe a bed that raises up out of the floor too?:D

[tod evans]

markus, the old satelite actuaters that all the larger dishes used run on 24v dc and generally offer 6-18" of travel if you`re looking for cheap(free)
if you`re looking for reliable look to pneumatics or hydraulics...02 tod

[Alex Shanku]

An air bag / bladder connected to a compressor of some sort?

[Ben Grunow]

I think those linear actuators (telescoping deals seen on monster garage) are noisy? I know there are lift mechanisms for projectors and plasma TVs that are small, quiet and electric but not cheap. A homemade linkage between the pedal and box would not cut it (you want to stand back and watch the magic)? That would be cheap and easy to work from a pedal. Let us know what you come up with.

[Bruce Shiverdecker]

I have seen pen boxs that have a "hidden" lift built into them.

You could incorperate an X bracket,with the far side legs tied to the lid, so that when you open the box, it causes a false bottom to rise.

Bruce

[Larry Crim]

Marcus if that does not work for you you may want to look into some wrecking yards there are several different types of window actuators for autos that will auto stop and will run off a 12 volt supply some are very small and the actuators vary so you should be able to find something that will work.
Pat

[Lou Morrissette]

Marcus,

If your application is lightweight, you might consider a laboratory jack stand used in chem labs to elevate lab equipment. Boston Scientific maybe?

Lou

[Mike Cutler]

Markus.

How much weight will it be lifting?
I like the idea of pneumatics, but the leveling air bags for an RV/trailer are about 6"-8" empty. The cost would be fairly high. My leveling system I just put on the truck was about 600.00.

One more option, along the lines of pneumatics, would be to get a muffin fan and mount it in the bottom of the box. Have it inflate a light weight plastivc bag with a thin piece of wood on the to to keep everything level. Fan on, and something rises, fan off and it sinks down. A 12vdc battery and a remote, and there would be no wires.

[markus shaffer]

Thank you everyone for your replies. All great ideas. I think Lou has hit upon the right idea with the lab jack (photo below).

The concept and size are both exactly what I was looking for. All I need to do is figure out how to motorize it now. There is a guy here in my neighborhood who build robots and other assorted wonders. I'm going to pay him a visit with this idea also.

Any other ideas, I'm still open.

Thank you agian everyone for your help so far. It is much apreciated.


-Markus

[Rennie Heuer]

Markus,

I'm always thinking frugal (read 'cheap), how about a rotisserie motor from a Bar-B-Q grill? I imagine there is a way to reverse it electronically - or you could just use 1 motor at each end of the shaft - 1 up, 1 down (as they oppose each other, face to face, one would turn opposite of the other). This should meet your 120v requirement.

Like I said…..cheap.

[Ian Barley]

.... All I need to do is figure out how to motorize it now...
-Markus
Markus

Think electric window motors from a car? The other alternative is some sort of stepper motor arrangement. Take a look on Ebay for stepper motors and controllers. I am investigating them myself for some workshop applications. It probably would not be the cheapest option but I suspect that it would be pretty robust.

[Al Willits]

I think window motors might be a bit fast for what he wants, although if you can remove the handle and install a gear on it then link to the motor with a gear, you could vary speed by changing gear ratios?

Surplus DC motors might be an option also, may find a slower motor.

Al

[Dave Richards]

I found a link to a site that sells geared AC motors. You could probably get one geared as needed. I've never had any dealings with them so this is not a reccomendation.
http://www.specializedgm.com/Shaded_Pole_Geared_Motors.html

And here's your lift. Either you can deconstruct it in SU or I can and give you dimensions. The only tough thing would be the threaded rod between the middle cross rods. It needs to have left hand threads on one side. Once you work that out, mount the geared motor in place of the knob and attach the motor housing so it can slide up and down without turning.

[Matt Warfield]

I didn't see if you were trying to lift the entire lid vertically or if it's hinged. I was thinking something along the lines of car lift gate hydraulics to lift the lid and then a small motor/pulley to reel it back down and activate the catch. Have a butterfly type foot pedal where one side activates the motor and the other side pulls a bicycle brake cable to release the latch.

Depending on the thickness of the sides, you may be able to embed the hydraulics into the side and have the motor covered by a false bottom. (not sure if you're looking to put anything in the box)

You may want to consider the effect of someone wanting to close it manually if this is going to be in a public setting. You may want it to either be strong enough to withstand this action or cooperative enough to allow it to be closed.

[David Wilson]

Thank you everyone for your replies. All great ideas. I think Lou has hit upon the right idea with the lab jack (photo below).

The concept and size are both exactly what I was looking for. All I need to do is figure out how to motorize it now. There is a guy here in my neighborhood who build robots and other assorted wonders. I'm going to pay him a visit with this idea also.

Any other ideas, I'm still open.

Thank you agian everyone for your help so far. It is much apreciated.


-Markus

Markus
Why not power this unit with a cheap cordless screw driver. The Ni-Kad battery would give you lots of actuation time on a charge and no other power source needed.

[Dave Richards]

Markus
Why not power this unit with a cheap cordless screw driver. The Ni-Kad battery would give you lots of actuation time on a charge and no other power source needed.


There you go. That's a great idea. You get reversible and variable speed. You could get one of the DeWalt 7.2V screwdrivers and take it apart at the hinge. The lower part has the battery, direction switch and speed control.

[markus shaffer]

Wow, the ideas just keep coming. Thanks again everyone for all the responses.

I think David Wilson's idea of using a cordless drill motor will work great. Basically this lift is going to have a false bottom inside the box and will lift it up. It'll probably be 1/4 inch plywood a little bit smaller than the interior of the box itself. It's going to have a light mounted to it and the idea is for it to rise up slowly and somewhat dramatically.

I'm going to take this idea over to the robotics guy in my neighborhood and see what insight he might have. Not being a metal worker, fabricating brackets and the such for the motor might be a bit beyond my skillset.

I'll keep you all posted.

-Markus

Oh and Dave Richards.. Thank you for the SketchUp diagram. I hope you didn't waste a lot of time working on that.

[Dave Richards]

Markus, it didn't take much time at all. I thought it might come in handy sometime anyway. I expect you could build it for less than buying one.

[Steven J Corpstein]

I would call some of the custom stereo installers in your area. One of the big fads going on right now in car stereo is to have the equipment hidden in the trunk.

At the touch of a button, the lid raises up on hydraulic cylinders by way of an electrical switch. Very subtle, quiet and extremely smooth. You may be able to purchase them online at crutchfield.com. Good luck.

[John Gornall]

Have a look at the motors and drives for electric beds - the ones that lift at the foot or head of the bed by a remote control. They are 110 volt and have a screw drive from a small electric motor and gearbox. They move quite slow - don't want to shoot Grandma into the hallway. They have motion limiters that stops them at the end of their stroke and a 3 way switch for up, down and stop. Don't have to buy the whole bed - spare parts are available.