Think tank advice

[ctjstr]

You'll need some pretty healthy gear reduction to turn the tube with the ramps hanging on it. We use large diesel truck starters running on 36 volts and unless we reduce the gearing, they won't even turn over the engine in our motorcycles.

 

[chickenman]

heres a lowtech approach

jack the trailer up 4-6 feet

hang wooden boxex from the ramps as on a trebuchet

fill the boxes with stones till the weight raises the ramps and secure ramps

empty boxes and remove

lower trailer to ground

voila

 

[speedy67]

If you're considering using hydraulics, how about taking a cue from the linkage used on an excavator or back-hoe bucket? You know, the two-peice linkage connected to the main stick and a point equi-distant from the pivot point and the cylinder on the stick and the point at which the two linkages connect with each other. I've attached a link to a patent, but the hydraulic cylinder is connected at a point not common to the two linkages, like I was describing....but I bet it'll still work.

 

[3RRL]

Steve,
Do you have any update or pictures of your progress? What are you up to?

 

[bones1]

Thanks Speedy but I have to rule out hydraulics and go with a 12 volt solution such as a winch or the linear motors from Northern Tools. Rob, still pondering this..what about using something like this Northern Industrial Linear Actuator 12 Volt, 11 13/16in. stroke | Trailer Jacks | Northern Tool + Equipment
Perfect for raising and lowering lawn and garden tractor and ATV attachments, along with hoods, trunks, tonneau covers, tailgates, truck cover and more! CE/UL-approved motor. Where would you mount it(or them) keeping in mind that the ramps have to be adjustable width wise to load a car or something smaller.

 

[3RRL]

I didn't realize those linear actuators were so powerful. They must be sorta like an electronic hydraulic cylinder, huh?

Well, you could use the same principal with the tube protruding out the side of the trailer. Fasten/weld/bolt a bar to the protruding tube and attach one end of the linear actuator to it and the other end of the actuator to the trailer frame or on a mount if needed. Only thing I see is the travel you need to get the ramps to go fully up and down. So the bar should be about 6" to 10" long (the protrusion) and should have some extra holes drilled in it so you can reduce the "radius" to give you more or less travel for the ramps. You may only need to rotate the tube 1/4 turn or so. I would clamp it first to find a relatively good position. The closer you connect it to the rotating tube, the harder it will be to rotate but it will rotate faster. The farther out you connect it, the easier it will be on the actuator and it will rotate slower.
(Assuming a constant linear actuator speed)

In fact, you could make a connector which will slide up and down on that protrusion...to increase or decrease the rotating radius. The connector would have a clamping bolt in it to fasten it's position to the protrusion bar when you find the right spot where the actuator will work best. The other end of the connector would be connected to the end of the linear actuator. You might be able to use only one linear actuator that way, if the correct radius allows enough travel and has enough power. If not, you can always add another one on the other side.

As far as being able to adjust your ramps, I would make the ramps so that they can be fastened to the rotating tube in various positions. That is, they should be able to slide on the rotating tube much like a fork lift's forks. Then pin them to the rotating tube which has holes in it for adjustment.

 

[bones1]

Thanks Rob, just what I needed to hear.This is exactly how I will do it.Trailer is in the barn now getting a winch installed so I really have no excuse to try it.

 

[3RRL]

When you get started on this project, be sure to take some pictures to share with us.

 

[bones1]

After much pondering and checking user reviews on these Northern Industrial Linear Actuator 12 Volt, 11 13/16in. stroke | Trailer Jacks | Northern Tool + Equipment
I have decided to use hydraulics to operate the ramps.I will design something along the lines of this truck mounted bale spear,although mounted underneath the trailer. Looks like it will move a 200 lb ramp up and down. Washburn Company and hayspear.com Pickup truck electric hydraulic hay bale spear fork unit T
What do you think?.

 

[bones1]

I think hydraulics might work.I started a mock up yesterday and got this far.
http://i24.photobucket.com/albums/c29/shenders/trailer026.jpg
http://i24.photobucket.com/albums/c29/shenders/trailer025.jpg
http://i24.photobucket.com/albums/c29/shenders/trailer022.jpg
http://i24.photobucket.com/albums/c29/shenders/trailer020.jpg
http://i24.photobucket.com/albums/c29/shenders/trailer031.jpg
Using shop air for testing the cylinder needs a little help in lifting them, a pinky will do .
I need about 3 inches more of throw so I can lock the ramps up in their original locked position but moving the mounting of the cylinder won't get me any more. Still scratching my head on that one. If I move the cylinder further out towards the ramps I can get a little more but then the ramps don't touch the ground when dropped.
Maybe a curved arm where the extended cylinder meets the box tubing??.Any thoughts much appreciated.

 

[jimmer2880]

Can you give us a pic from a side angle so we can see the angle of the cylinder? I'm not sure I can help, but without side views, i'm really stumped

 

[jimmer2880]

If you were to raise the attach point of the rod side, closer to the ramps, that should give you what you need. You may have to adjust the cylinder side towards, or away from the rod then to get the positions you want. Of course, that will lessen the lifting power of your hydraulics. But, I don't think what will be a problem once you get hydraulics hooked up.

something like this:

 

[bones1]

Jimmer, you are the man.After 2 days of messing with it I had come to the conclusion that I could have all the way up or all the way down but not both.After your post I gave it one more try as you suggested but I moved the whole square cross tube up about 4 inches.It worked perfect.I have complete up and down travel and never moved the cylinder.Thanks a lot.
Now for making them adjust for different width vehicles.

 

[jimmer2880]

Good. I'm glad you were able to get it working. Also glad that my very crude drawing was enough to get my idea across

So, let's see some action shots!

 

[bones1]

The hydraulic ramps are finally finished thanks to Jimmer, 3RRL and others. I dropped the pressure down on the pump until they operate nice and smooth.
Thanks you guys for the inspriation.
Video of RAMPS - Photobucket - Video and Image Hosting and some more pics.

 

[jimmer2880]

Very cool video. I am definitely envious of your ramps. Nice work. Care to come make a set for me?

 

[rtdiggr]

I will take a set too please.

Shane

 

[3RRL]

Wow Steve,
Great job on those ramps!
You sure did some clean work there. No more back pains either. Thanks for sharing that cool video, I'm sure there are a bunch of us guys who could use a set like that.

 

[Kendrick]

I skimmed through and think some one else had kinda suggested this. I think this would be the cheepest and quite simple of a solution.

In the pic i added 2 red lines reprasenting square post that would be detachable from the ramps. the kinda purple lines would be where you could run the cables. probably having a pully like device welded at the wheelwell area would be best.

you could go with 1 or 2 winches and adjust the lenghts to make the lifting force of appropriate level. another thought would be to use a block & tackle system that would lift both gates with 1 winch. It would just require a long cable to do it.

 

[bones1]

Kendrick, your idea was very good but because of the wooden rails and a possible clearance problem when loading cars I had to go underneath with hydraulics to make it work. Would have been easier to do though.Thanks again for the advice.