What about just building ramps or wedges to "fill in" the lowest portion of the angled ramp for the loading dock? Something that would allow you to back the trailer in at the proper height and level instead of at an angle? Drag them out of the way, or load them up when they're not needed? Seems far easier to me than designing an articulating trailer.
So your loading dock would become something like this:
Edit: Looks like it was already suggested and addressed.
dculberson said:A rental truck is so, so cheap that I can't imagine ever actually saving money with this. It might be more convenient but that's a totally different calculation!
Not sure where you're renting, but a 26' box truck for two days of load-in and two days of load-out is usually over $700 per show, and that's with a steep discount for running a full-page ad in the program for the rental company.
$700 x 6 shows per year is $4200. Contrast that with free trailer to start with, (donation) free steel leftover from other theater projects, (already budgeted to a different production) a free 5hp motor, (donation of a pressure washer with a bum pump) and I'm looking at just the cost of the welding wire and the electric and the hydraulic parts. Total investment will likely be $1500 or less, so this will pay for itself in two shows.
STM317 said:What about just building ramps or wedges to "fill in" the lowest portion of the angled ramp for the loading dock? Something that would allow you to back the trailer in at the proper height and level instead of at an angle? Drag them out of the way, or load them up when they're not needed? Seems far easier to me than designing an articulating trailer.
Edit: Looks like it was already suggested and addressed.
Yeah, and there is far more material and construction involved with the ramps than there would be adding a subframe to my trailer.
I really started this thread for ideas on how to do the lifting part, but I also did say "critique my idea." 
How about this.... I am building a trailer that will lift from about 32" to 48". Here is the most likely design (see first post). How would you lift it? Hydraulics and a bellcrank? Screw drive? Semiconductor magnet levitation? Criss Angel magic?
Not to scale, but if the trailer frame is strong enough for the loads:
I like that idea. Just basically ram up the ass end.
(edit: I need to work on my phrasing.)
My original thought with lifting from the axles was that I could move fore/aft after it's up. Instead of guessing where the deck will be once it's up, I could rough the up/down, back in, and fine tune the up/down.
But your option sure makes it an easy modification. Something like that could be done like a scissor jack, or even a reverse lift gate type idea.
OR... that's where streetwiseguy's suggestion would come in handy... Take one side of that scissor lift and mount it sideways under the tail with an articulating foot (to account for different terrains). Power the ram with a gas motor and hydraulic pump.
Just looked at your picture again.
Is that passive? As in, you set the foot down and use reverse to lift the trailer? That's pretty berkeleying genius.
The trailer started as a section of mobile home frame, so it's plenty beefy.
Streetwiseguy said:
Here is the basic idea. Remove the parts you don't need.
This; but make the front pair of rams operate independently from the rear.
iansane said:Streetwiseguy said:
Here is the basic idea. Remove the parts you don't need.
This; but make the front pair of rams operate independently from the rear.
that would be great, but I don't plan on unhitching.... at least I don't see the need for unhitching.
In reply to Curtis73 :
It is passive. the bottom section would contact the base of the dock as a stop, and if you go over-center gravity can help keep it secured in the up position (although I would pin it to be sure)
The loading docks should be close enough that if you use wood blocks between the foot and the base of the dock you could fine tune the position. Once you get the right blocks for each dock you should be able to repeat it on the first shot.
Unhitch? I didn't think you'd unhitch unless you were lifting the whole trailer an appreciable amount. With independently operated rams the front would only have to raise a few inches while the back could come up a few feet, as long as the slides were long enough.
In reply to iansane :
Oh... I thought you meant put one scissor/ram at the front of the trailer and one at the rear. I was thinking just one at the back and let it articulate on the hitch ball.
No Time said:In reply to Curtis73 :
It is passive. the bottom section would contact the base of the dock as a stop, and if you go over-center gravity can help keep it secured in the up position (although I would pin it to be sure)
The loading docks should be close enough that if you use wood blocks between the foot and the base of the dock you could fine tune the position. Once you get the right blocks for each dock you should be able to repeat it on the first shot.
Could also mount the "stilts" on a heavy duty tongue jack. Once up and over-centered you could fine tune with a few turns of the jack handle. Or, get really fancy and weld on a dock plate. Stilts up until the tail hits the bumpers on the dock, then lower the jacks until the plate rests on the dock. This would not only provide vertical support, but much needed lateral support. Like this awful, terrible drawing:
No Time said:Not to scale, but if the trailer frame is strong enough for the loads:
As long as this can tuck up, that's awesomely simple.
Film crews (which are completely mobile) use box trucks with lift gates.
I know you are considering the budget, but what do you do when you have to load out a show in the pouring rain? Hauling scenery on an open trailer could mean damaging the scenery.
Could you purchase a box truck? They seem pretty cheap.
I know. That’s not the question you asked...
iansane said:No Time said:Not to scale, but if the trailer frame is strong enough for the loads:
As long as this can tuck up, that's awesomely simple.
I would likely do it as two separate posts tied together that could flip up as a tailgate/ramp.
I will have to look at/measure the trailer. It's possible that the approach angle might be unfavorable. If the 4' legs can go down and be at a 45 degree angle, it might work. I'm just thinking with a 5k load on there, will the truck effectively be able to safely provide the linear force necessary to overcome the lifting action.... and provide enough braking to lower the same load.
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